arXiv · cs.LGConceptual★ flagship
A stress-tested toolkit to check whether medical AI quietly fails some patient groups.
Medical risk-prediction models can look great overall while making far more mistakes for certain groups of patients — say, by income, geography, or disability. People have built 'audit' pipelines to catch this bias, but the auditing tools themselves are rarely tested to see when they break or mislead. KAISEN is a five-stage audit — find subgroups, measure the gaps, diagnose why they happen, try to fix them, and watch for drift over time — deliberately pushed until it fails on a large synthetic testbed of 16 diseases and 15 social-factor dimensions. A key lesson: whether a disparity shows up as 'statistically significant' depends heavily on how big a gap that particular subgroup axis is even capable of detecting, not just on how unfair the model actually is. The point is to tell practitioners which parts of an audit to trust, and under what conditions.
Technical view
KAISEN is a reproducible five-phase fairness-audit pipeline — subgroup stratification, disparity measurement, mechanism diagnostics, post-hoc mitigation, and drift monitoring — evaluated to failure on a synthetic benchmark of 16 disease tasks, 15 social-determinant axes (from Healthy People 2030), and three prespecified intersections. A headline result: significance counts track each axis's gap relative to its own minimum detectable effect, with rank correlation ρ=0.56 between significance count and raw equalized-odds difference (EOD), rising further under stated conditions — i.e., detected 'significance' is confounded by per-axis statistical power. Practitioners can use the framework to distinguish genuine subgroup disparity from artifacts of detectability, and to sanity-check which audit components remain reliable under stress.
arXiv · cs.MAConceptual
Your brain does cost-benefit math before deciding whether to copy someone or figure it out yourself.
This paper asks a simple question: when do people learn by watching others versus by trying things themselves? The researchers built a model where an agent thinks about what another person is trying to do and how useful watching them would actually be, then compares that against the cost of just exploring on your own. They tested this with a game where players choose to either observe others or explore the environment themselves, and found the model correctly predicted people's real choices. The big idea is that copying others isn't automatic — it's a calculated decision guided by 'Theory of Mind,' our ability to reason about what's going on in someone else's head.
Technical view
The authors formalize a 'Rational Mentalizing' model that computes the expected utility of social learning by inverse-planning over another agent's goals to estimate the informativeness of their likely future actions, then compares this against the utility of independent exploration under a shared cost structure. Validated on a novel game requiring players to choose between observation and exploration, the model quantitatively fits human behavioral trade-offs, outperforming presumably simpler heuristics. This connects Bayesian Theory-of-Mind inference (used elsewhere for goal/intent inference) to the explore-exploit and social-learning literatures, offering a computational account that could be extended to multi-agent or robotic social learning systems.
arXiv · q-bio.QMBuildable
A new math tool tracks how a disease spreads hour-by-hour as people commute, not just city to city.
Epidemiologists usually estimate how fast a disease is spreading using a single number, R(t), that assumes everyone mixes together evenly all day — but real people commute, cluster at work, and disperse at night, which changes how infections actually pass around. This research builds a new mathematical framework that factors in these daily movement patterns between locations, creating several versions of R(t): one for how many infections a place sends out, one for how many it receives, and others for specific commuting routes or meeting spots. The method is built on 'renewal equations,' a standard epidemic-modeling tool, but reworked to plug in real mobility data. This matters because public health responses — like where to focus testing or restrictions — could be much sharper if they account for how people actually move rather than treating populations as uniformly mixed blobs.
Technical view
The paper derives mechanism-led renewal equations on a network-based mobility model, decomposing the classical instantaneous reproduction number R(t) into a family of location- and route-specific indicators: inward and outward R(t) per location, pairwise R(t) between locations, R(t) at shared meeting sites, and an aggregate network-level R(t), all incorporating within-day (not just day-to-day) movement heterogeneity. This generalizes standard homogeneous-mixing renewal-equation estimators (e.g., Cori et al.-style methods) to explicitly encode commuting-driven contact structure. Practitioners with mobility datasets (transit, mobile phone, or census commuting matrices) could use these formulas as drop-in replacements for real-time surveillance to identify which locations or routes are driving transmission, enabling targeted rather than uniform interventions.
bioRxiv · bioinformaticsBuildable
Mapping gene activity along the natural curved paths of tissue, not a flat grid.
Spatial transcriptomics is a technology that measures which genes are active at each location across a slice of tissue, like a detailed activity map layered onto a photo. Scientists often want to find genes whose activity changes meaningfully across a specific region, say a strip of tissue like a blood vessel wall or intestinal lining, but that region isn't really flat, it's more like a curved one-dimensional path. Standard methods that just use x-y coordinates miss this natural shape and give messy or misleading results. This paper's approach first mathematically finds the best-fitting curve that traces the tissue's true structure, re-maps every measurement onto that curve, and then uses a flexible statistical model to detect which genes vary meaningfully along it, giving biologists a more accurate way to spot genes tied to a tissue's real anatomical organization.
Technical view
The method addresses spatially variable gene (SVG) detection within tissue regions that are effectively 1D manifolds, such as epithelial layers, where standard 2D coordinate-based SVG methods underperform because they ignore the region's intrinsic geometry. It uses spectral graph theory to extract a principal curve approximating the spatial coordinates of the region, establishing a morphology-aware 1D coordinate system, then fits a GAM (generalized additive model) over this coordinate to detect genes with significant spatial patterns. This provides a more statistically powered and biologically interpretable alternative to 2D spatial smoothing methods for structurally constrained tissue regions. Practitioners working with spatial transcriptomics data, such as Visium or Slide-seq, could adopt this as a preprocessing coordinate-transform step ahead of existing SVG detection pipelines.
bioRxiv · neuroscienceConceptual
One gene keeps human brain development from rushing, and losing it may cause autism-linked delays.
Human brains take an unusually long time to develop compared to other animals, and scientists think that slow pace is part of what makes advanced thinking possible. This study looks at a gene called RAI1, which normally helps package and control DNA in developing brain cells, and which is missing a working copy in people with Smith-Magenis Syndrome, a condition involving intellectual disability and autism-like traits. The researchers built stem cell lines missing one or both copies of RAI1 and grew them into brain tissue in a dish, tracking gene activity over time as the cells matured. They found that without enough RAI1, the developmental gene program runs on fast-forward instead of unfolding at its normal careful pace, and single-cell analysis showed how this speed-up plays out across different developing brain cell types. The findings suggest that RAI1's job is essentially to act as a pacesetter, protecting the accuracy and tempo of brain development, and that rushing this timeline may be part of what goes wrong in Smith-Magenis Syndrome.
Technical view
Using isogenic RAI1 heterozygous and homozygous loss-of-function hESC lines differentiated via an in vitro cortical protocol, the authors performed longitudinal bulk transcriptomics and found that RAI1 deficiency accelerates progression through the normal developmental gene expression trajectory. Single-cell RNA-seq further resolved how this temporal acceleration manifests across distinct neural cell populations during differentiation. RAI1 encodes a nucleosome-binding protein, so the phenotype implicates chromatin-level regulation of developmental gene timing, linking RAI1 haploinsufficiency (the cause of Smith-Magenis Syndrome) to disrupted pacing rather than simple loss of gene expression. This isogenic hESC system provides a tractable platform for dissecting how chromatin regulators set neurodevelopmental tempo and could be extended to test other SMS-linked mechanisms or candidate therapeutics that restore normal timing.
bioRxiv · cell biologyBuildable
Scientists filmed individual mRNA molecules moving inside living stem cells as they choose their fate.
Inside a cell, messenger RNA (mRNA) molecules carry instructions from DNA to the machinery that builds proteins, and where those instructions end up inside the cell can matter as much as what they say. This study built a way to tag specific mRNAs in living human stem cells with a glowing marker so researchers could watch individual molecules move in real time under a microscope, using computational tools to classify their movement patterns. They applied this to cells becoming neurons or blood vessel tissue and tracked mRNAs that encode building blocks of the cell's internal skeleton. As cells committed to a final identity, these mRNA molecules consistently shifted from moving freely to being locked into specific zones of the cell, and disrupting the cell's internal scaffolding changed this pattern. This shows that controlling exactly where mRNA sits, not just how much of it exists, is a conserved part of how a cell settles into its identity.
Technical view
The authors developed an MS2-tagging pipeline for endogenous transcripts in human iPSCs, combined with single-particle tracking and Hidden Markov Modelling to classify mRNA diffusive states and construct mobility landscapes during differentiation. Applied to beta-actin and beta2b-tubulin transcripts across neural organoids, directly programmed neurons, and vascular organoids, particle tracking revealed a conserved shift from free diffusion toward constrained, compartmentalized mobility states as cells acquire terminal identity. Cytoskeletal perturbation experiments (implicating microtubule-dependent transport) causally link this mobility shift to the underlying transport machinery rather than passive diffusion changes. The tagging and HMM-based analysis pipeline is generalizable to other endogenous transcripts and cell systems, offering a route to quantitatively map RNA localization dynamics genome-wide during any live cell-state transition.
bioRxiv · cell biologyConceptual
Two DNA-organizing proteins fight for control at chromosome loop boundaries to flip cells between dividing and resting.
Our DNA is folded into loops inside the nucleus, and the anchor points of these loops help decide which genes turn on or off. This study looks at how cells switch between actively dividing and resting quietly, a switch that happens without the loop anchors themselves moving. The researchers found that two players compete for control at these anchor points: a protein called CTCF that favors active, dividing cells, and a chemical tag on DNA-packaging proteins called H4K20me3 that favors resting cells by physically pushing CTCF out of the way. When they experimentally boosted H4K20me3, cells compacted their DNA, changed the shape of their nucleus, and switched on resting-state genes, and removing the enzyme that makes this tag broke the resting program. In short, a tug-of-war between one protein and one chemical mark, rather than any big rearrangement of the DNA's overall folding, appears to control whether a cell divides or rests.
Technical view
The study identifies a reciprocal antagonism between CTCF occupancy and the histone mark H4K20me3 at TAD (topologically associating domain) boundaries as a mechanism controlling the proliferation-quiescence switch independent of large-scale TAD repositioning. Genome-wide profiling and functional perturbation show elevated H4K20me3 in quiescent fibroblasts displaces CTCF at specific boundaries, driving compact chromatin, altered nuclear morphology, and quiescence-associated transcription, while CTCF binding dominates in proliferating cells and sustains open chromatin and pro-proliferative gene expression even under quiescence cues. Fibroblasts lacking the H4K20me3 methyltransferase KMT5C/Suv4-20h2 show a hyperproliferative phenotype, functionally validating the mark's necessity for the quiescent state. This establishes a boundary-level, mark-versus-factor competition model that practitioners could test at other TAD boundaries or in other cell-state transitions using ChIP-seq/Hi-C plus KMT5C perturbation.
bioRxiv · ecologyConceptual
A horse's genes and its friends both help shape the gut microbes that decide whether it thrives.
Scientists have long known that the trillions of microbes living in an animal's gut can affect its health and survival, but it's been unclear whether this microbiome can actually evolve the way genes do, and whether it's just inherited genetically or also passed along socially, like from a mother or from friends. This study used nearly a decade of data from wild horses living on Sable Island, including genetic records and stool-based microbiome sequencing from almost 800 individually tracked horses, to figure out how much of the variation in gut microbes linked to survival and reproduction comes from genes, from mothers, or from social relationships. They used statistical models borrowed from animal breeding science to tease apart these different sources of inheritance, applied to microbiome traits that were mathematically linked to fitness outcomes. The approach lets them ask, for the first time in one study, both whether these fitness-relevant microbiome traits are heritable and whether natural selection is acting on them. This matters because it suggests an animal's gut community isn't just a personal, one-off trait, but something that can be inherited and evolve across generations through multiple channels at once.
Technical view
Using quantitative genetic 'animal models' applied to shotgun metagenomic data from 2,394 samples across 794 known-fate feral Sable Island horses, the authors partition variance in fitness-associated microbiome dimensions (derived via canonical analysis of principal coordinates) into additive genetic, maternal, and social-transmission components. This is the first study to jointly estimate microbiome heritability and detect natural selection acting on microbiome traits within the same population, while also testing non-genetic inheritance pathways (maternal and social) as contributors to microbiome-mediated fitness variation. The long-term, individual-based pedigree and metagenomic dataset allows disentangling genetic versus environmentally/socially transmitted microbiome effects at a scale rarely available outside model organisms or humans. The animal-model framework applied here is replicable in other wild or captive populations with pedigree and longitudinal metagenomic data to test whether microbiome-mediated adaptation is a general evolutionary phenomenon.
bioRxiv · ecologyConceptual
Diamondback moth caterpillars need different diets to grow fast, fight infection, or survive stress.
This study looks at diamondback moth caterpillars, a major crop pest, and asks a simple question: does the 'perfect diet' look the same no matter what the body is trying to do? Using a method called the Geometric Framework for Nutrition, researchers fed caterpillars many different mixes of protein and carbohydrate and tracked growth, immune strength, and stress resistance separately. They found that growth mainly needs plenty of protein, but the immune system (measured by immune cells and a defense enzyme) peaked at a middle-ground protein-to-carb ratio, while surviving a bacterial infection depended almost entirely on protein again. In short, there's no single 'best' diet — the ideal balance shifts depending on whether the body is building itself, defending itself, or coping with stress, which matters for understanding animal health and even for designing pest control strategies.
Technical view
Applying the Geometric Framework for Nutrition, the authors mapped Plutella xylostella performance across a protein:carbohydrate (P:C) nutrient space, showing growth (biomass) is protein-limited while immune traits (hemocyte counts, phenoloxidase activity) peak at intermediate P:C ratios distinct from the growth optimum. Survival after Bacillus thuringiensis challenge tracked protein intake specifically, and antioxidant/detoxification enzyme responses varied non-linearly and non-uniformly across the nutrient landscape. This demonstrates trait-specific rather than universal nutritional optima, a finding replicable via response-surface/GF designs in other insect systems and relevant to integrated pest management (e.g., optimizing host-plant nutrient content to suppress pest immunity or stress tolerance).
bioRxiv · ecologyConceptual
Diseases that spread two different ways don't automatically become more common — it depends on the trade-offs.
Parasites and pathogens spread between hosts in different ways: some depend on crowding (density-dependent, like a cold spreading faster in a packed room), others spread at a steady rate no matter how many hosts are around (frequency-dependent, like an STI). Many real diseases actually use both routes at once, so this study built a model to ask whether combining transmission modes makes outbreaks worse. Using a mathematical model with a built-in trade-off (getting better at one transmission route means getting worse at the other), the researchers simulated infection spread under single versus mixed strategies. Surprisingly, mixing modes only boosts how common a disease becomes when the two routes also affect the host's health or reproduction differently — otherwise mixing transmission strategies gives no special advantage, which reshapes how epidemiologists should think about multi-route diseases like some sexually transmitted or environmentally persistent infections.
Technical view
The authors build an epidemiological model comparing single-mode (purely density- or frequency-dependent) versus mixed-mode transmission under an imposed linear trade-off between infection probabilities via each route, then compare equilibrium prevalence. Key result: mixed-mode transmission only exceeds single-mode prevalence when the two transmission routes differentially affect host fitness (e.g., differing virulence or fecundity costs per route); absent that fitness asymmetry, mixing modes confers no prevalence advantage over the best single mode. This is a useful null result for modelers of STIs, vector-borne, or environmentally transmitted pathogens — it suggests searching for route-specific fitness costs before attributing high prevalence to transmission-mode diversity per se.
bioRxiv · ecologyRunnable
Fungal 'bio-pesticides' protect date palms from a deadly weevil for six months without wrecking soil life.
The red palm weevil is a devastating pest of date palms, and instead of chemical pesticides, researchers tested two natural fungi that infect and kill insects (entomopathogenic fungi) as a preventive treatment. They applied the fungi to palm soil, then tracked how long the fungi survived, how well they protected the trees, and — crucially — whether they disrupted the broader community of microbes living in the soil, using genetic sequencing and lab culturing. Both fungal species stuck around in the soil for a full 180 days and meaningfully reduced weevil damage, though one (Beauveria bassiana) gave longer-lasting protection than the other. Reassuringly, the overall soil microbial community stayed largely intact, suggesting these fungi can be used as an environmentally friendly pest control tool without collateral damage to soil ecosystems.
Technical view
Researchers applied Metarhizium brunneum and Beauveria bassiana as preventive soil treatments against Rhynchophorus ferrugineus on date palms, quantifying fungal persistence via culture-based isolation and high-throughput metagenomic sequencing of soil microbiota over 180 days, alongside continuous palm health monitoring. Both EPF species persisted for the full 180-day window and significantly reduced weevil damage, with B. bassiana outperforming M. brunneum in duration of protection despite comparable persistence; critically, metagenomic community-level analysis showed no major shifts in overall soil microbiome composition post-application. This supports EPF as a non-disruptive biocontrol option for palm plantations and provides a persistence/efficacy benchmark (180-day window) and a metagenomic protocol for assessing off-target microbiome effects in future biocontrol deployments.
bioRxiv · geneticsConceptual
A popular gene-hunting method for 'flexible' traits is mathematically blind to the very flexibility it claims to find.
Plants and animals often show plasticity — the ability to change their traits depending on the environment — and scientists want to find the genes behind that flexibility using a statistical method called CERIS-JGRA, which builds a climate-based 'environmental index' to compare against average performance. This paper is a critique: it shows mathematically that the way the index is constructed forces it to closely track the environmental average, which is exactly the wrong thing if you want to isolate plasticity (the part of the response that's independent of the average). The authors prove that the more correlated the index is with the mean, the less room is left for it to capture true plasticity signal, and they confirm this shortfall with simulations. The takeaway is a cautionary one for genetics: a widely used tool for finding 'flexibility genes' may be systematically weak at its core job, so scientists need to rethink how they build these environmental indices.
Technical view
The paper formally analyzes CERIS-JGRA, a reaction-norm GWAS method that substitutes a climate-derived environmental index for the Finlay-Wilkinson environmental mean. It proves that an index with correlation ρ to the true environmental mean decomposes as ρ·(mean) + residual, meaning its loading τ on mean-orthogonal (plasticity-relevant) variation is bounded by √(1−ρ²) — and since the algorithm is constructed to maximize ρ, it necessarily minimizes τ, and thus the non-centrality of any plasticity-specific association test (which scales as τ²). Simulations across 189 conditions confirm this predicted power loss with a parameter-free closed-form expression matching observed results. Practically, this implies GWAS practitioners using CERIS-JGRA-style indices should decouple index construction from mean-correlation maximization if they want statistical power to detect genotype-by-environment/plasticity loci rather than just mean-performance loci.
bioRxiv · biochemistryBuildable
AI redesigns a fish toxin into a smarter antibiotic-resistant bacteria killer.
Antibiotics are losing their power because bacteria keep evolving resistance to them, so scientists are hunting for entirely new kinds of weapons. One promising class is antimicrobial peptides — short chains of amino acids that punch into bacterial membranes rather than working like traditional drugs. Here researchers started with pardaxin, a peptide from fish that already damages bacterial membranes, and used an AI protein-language model (like a spellchecker trained on millions of proteins) to suggest small swaps in its sequence that might make it even better at killing germs like E. coli and Staph. Combining the AI's suggestions with established peptide-design rules let them narrow down which tweaked versions are worth testing in the lab, speeding up the search for the next generation of infection fighters.
Technical view
The team performed in silico point-mutation scans on the antimicrobial peptide pardaxin, using embeddings from ESM Cambrian (ESMC), a protein language model, to score candidate substitutions alongside conventional AMP design heuristics (e.g., amphipathicity, net charge, hydrophobic moment). Principal component analysis on the ESMC embedding space was used to identify single- and likely multi-substitution variants clustering toward regions associated with improved membrane-disruptive activity. This embedding-plus-rules pipeline offers a template other groups could reuse to triage AMP variant libraries computationally before committing to synthesis and MIC assays against pathogens like S. aureus and E. coli.
bioRxiv · biochemistryRunnable
A glowing protein flashes 55x brighter in red light whenever calcium surges in cells.
Scientists studying brain and cell activity often want to watch calcium ions flowing in and out of cells, since that flow signals things like neurons firing. Normally this requires shining light on the tissue to make a fluorescent marker glow, but that light can damage tissue and doesn't penetrate deep. This team built a molecule called HyBRIC that instead makes its own light — bioluminescence, like a firefly — and combined two tricks: an enzyme (luciferase) that switches on with calcium, and an energy-transfer relay that shifts the glow into red light, which passes through tissue much better than other colors. The result is a calcium sensor that lights up roughly 55 times brighter when calcium rises, giving researchers a clearer, deeper, excitation-free window into living cells.
Technical view
HyBRIC and HyBRIC2 are genetically encoded bioluminescent Ca2+ indicators that couple Ca2+-dependent luciferase activation with bioluminescence resonance energy transfer (BRET) to shift emission into the red optical window, where tissue absorption/scattering is minimized. Using the luciferin substrate pyCTZ, the sensors achieve ~55-fold Ca2+-dependent signal increases in vitro, with HyBRIC2 offering improved brightness and response kinetics over HyBRIC in mammalian cells. This addresses the historically low dynamic range of bioluminescent indicators relative to fluorescent GCaMP-type sensors, and the modular BRET/luciferase-activation architecture is a design a lab could adapt to other analytes or luciferin variants for deeper, excitation-free in vivo imaging.
bioRxiv · bioengineeringConceptual
Old thymus tissue gets ten times stiffer — and that clue could guide lab-grown immune organs.
The thymus is the organ that trains your immune system's T-cells, but it shrinks and weakens dramatically as we age, a process called involution. Rather than just looking at which cells disappear, this study treated the thymus like a material — measuring its stiffness, its chemical makeup, and the arrangement of fats and minerals inside it — by comparing young and old cow thymus tissue with lab techniques like rheology (squishiness testing) and mass spectrometry imaging (a chemical map). They found aged thymus tissue becomes dramatically stiffer and more brittle, and its fat composition shifts, especially toward fat-storage molecules called triacylglycerols. Understanding these physical and chemical changes gives engineers a blueprint for building artificial thymus-like materials that could one day help restore immune function in older or immunocompromised people.
Technical view
The authors characterized young versus aged bovine thymus using histology, oscillatory rheology, untargeted lipidomics, ICP-MS, and AP-MALDI mass spectrometry imaging to build an integrated mechanical-compositional-spatial profile of thymic involution. Aging increased both storage and loss moduli by over an order of magnitude while narrowing the linear viscoelastic region ~5-fold, indicating a much stiffer, more strain-sensitive tissue state, accompanied by lipidomic remodeling (notably a doubling of triacylglycerol contribution to the lipid pool). These quantitative benchmarks — stiffness ranges, viscoelastic limits, lipid ratios — provide target design parameters for engineers building thymus-mimetic scaffolds or hydrogels intended for immune tissue regeneration.
bioRxiv · bioengineeringBuildable
A living-synthetic hybrid 'skin' lets scientists test sunscreens without animals or guesswork.
Testing sunscreens, cosmetics, and medical light-based devices usually means either using synthetic fake skin, which behaves predictably but isn't truly biological, or lab-grown living skin, which is realistic but varies too much between batches to trust for precise measurements — and increasingly, companies want to avoid animal testing altogether. This paper builds a middle-ground: a modular 'bio-hybrid' skin made of an engineered artificial top layer — using color-changing nanoparticles to mimic different skin tones — layered with real living human skin cells (keratinocytes) underneath. In one demonstration, they shine UV-B light on it and measure the resulting cell death, mimicking sunburn damage, to show the model can quantitatively capture real biological injury from light exposure. This gives researchers a tunable, reproducible, animal-free platform to test how light-based technologies affect real human skin.
Technical view
The bio-hybrid skin model combines an optically engineered synthetic epidermal layer — polydopamine nanoparticles tune melanin-like optical absorption to represent different skin tones — with living primary human keratinocytes cultured in 2D and 3D configurations, aiming to merge the reproducibility of synthetic optical phantoms with the biological authenticity of tissue-engineered skin. In their 'Optical Protection Model,' the team quantified UV-B-induced apoptosis in the keratinocyte layer, demonstrating that the construct can serve as a dose-response readout for phototoxicity and photoprotection testing. This modular architecture is positioned as an animal-free validation platform for optical biomedical devices (e.g., sunscreens, phototherapy, diagnostic optical sensors), and the polydopamine-tone-tuning approach could be extended to model diverse skin pigmentation in device safety testing.
bioRxiv · bioengineeringRunnable
Fake AI-generated brain scans help teach tumor-finding software with less real patient data.
Training AI to spot brain tumors in MRI scans normally needs thousands of scans that a doctor has painstakingly outlined by hand, which is expensive and slow to produce. This study tests a shortcut: using a generative AI model (a DCGAN, a type of network that learns to produce realistic fake images by having two networks compete against each other) to manufacture extra synthetic brain MRI images. They then auto-generate approximate tumor outlines for these fake images and mix them into the training set for a tumor-segmentation AI called U-Net, comparing performance against a version trained only on real data. The question they're answering is whether 'padding' a small real dataset with AI-generated synthetic examples meaningfully improves how well the segmentation model finds tumors on new, unseen scans.
Technical view
The authors trained a DCGAN on the LGG-MRI dataset (3,929 image-mask pairs) to generate synthetic brain MRI slices, then produced pseudo-segmentation masks for these synthetic images via thresholding, creating an augmented training corpus for a U-Net tumor-segmentation baseline. They compare segmentation performance (presumably Dice/IoU) between a U-Net trained on the original dataset alone versus one trained on the GAN-augmented set, evaluated on a held-out real test split. This is a data-centric AI study — the contribution is empirical evidence on whether GAN-synthesized images with heuristic pseudo-labels are a viable low-cost substitute for expert-annotated data in low-resource medical segmentation pipelines.
bioRxiv · bioengineeringBuildable
Bioprinted living tissue folds and morphs into shape on its own, powered only by its own cells.
When your body builds tissues during development, cells don't just sit still — they physically pull and push on their surroundings to sculpt complex 3D shapes, a process called morphogenesis. Standard 3D bioprinting produces static structures, but this work creates a '4D' bioprinting platform, meaning the printed structure keeps changing shape over time after printing, entirely on its own. The trick is printing dense strands of living cells inside a temporary scaffold material that quickly dissolves; as it dissolves, the cells connect into networks and use their own natural contracting force — the same kind of pulling cells do inside real tissue — to bend and reshape the surrounding soft gel into a programmed final form, with no external triggers like heat or light needed. By controlling where the cell strands are placed, researchers can essentially program the tissue's contraction to fold into custom-designed shapes, opening a path to building more lifelike, self-organizing tissue structures for research or transplantation.
Technical view
The platform prints high-density cell strands using a fast-degrading sacrificial carrier bioink embedded within a mechanically compliant, self-softening base hydrogel. As the carrier degrades during culture, cells proliferate and form interconnected networks whose endogenous cellular contractile force (CCF) drives autonomous, spatially programmable shape morphing of the surrounding hydrogel — a genuinely self-actuating 4D system requiring no external stimuli (light/heat/pH) to trigger shape change, unlike most existing 4D bioprinting approaches. Spatial patterning of the embedded cell-strand geometry acts as the design parameter for the final morphed architecture, suggesting a generalizable strategy for engineering tissues that recapitulate developmental folding/morphogenesis for regenerative or disease-modeling applications.
bioRxiv · bioengineeringBuildable
Four tiny cameras team up on one head-mounted chip to film a mouse's whole brain surface at once.
Neuroscientists want to watch individual brain cells firing across a large area of the brain's surface at once, ideally with a lightweight camera small enough for a moving animal to wear. The problem is that miniature microscopes force a tradeoff: you can see a wide area or you can see fine cellular detail, but existing optics struggle to do both without becoming bulky and complicated. This team's solution splits the job across four separate small optical 'modules,' each capturing a piece of the field of view, and then uses computation to digitally stitch their measurements back together into one sharp, wide image on a shared sensor — essentially trading some optical complexity for computing power. The result, called Bio-CM2, aims to let scientists image cellular activity across a much larger swath of the brain's cortex than typical miniature microscopes allow, without sacrificing sharpness.
Technical view
Bio-CM2 implements 'distributed computational optics,' partitioning the imaging field-of-view across four coordinated miniature optical modules that each capture a sub-FOV onto a shared image sensor, with computational reconstruction integrating the multi-module measurements into a single cellular-resolution, millimeter-scale image. This architecture sidesteps the aberration-scaling problem that limits conventional single-lens miniature microscopes as FOV grows, while avoiding the bulk/complexity of multi-sensor or scanning-based wide-FOV systems. The approach is relevant to anyone building head-mounted or wearable mesoscopes for freely behaving animal imaging, offering a modular hardware+computational-reconstruction template for scaling FOV without proportionally scaling optical complexity or device weight.
bioRxiv · bioinformaticsRunnable
A new tool maps exactly how RNA and DNA physically touch proteins, even in AI-predicted structures.
Many crucial cell processes depend on RNA or DNA physically interacting with proteins, but figuring out the precise 3D shape of these interactions has been historically hard, even though AI tools like AlphaFold3 now predict more of these structures than ever. The problem is that once you have a structure — whether solved by experiment or predicted by AI — there hasn't been a good, unified tool to actually analyze and make sense of how the pieces are touching. ProNA3D fills that gap: it's a software platform that takes these protein-nucleic acid structures and measures the distances and contacts at their interface, scores how trustworthy AlphaFold3's predictions are, and produces visual maps (both 2D diagrams and secondary-structure diagrams) so researchers can interpret exactly where and how the molecules interact, including inside blurry cryo-EM density maps.
Technical view
ProNA3D is an analysis platform for protein–nucleic acid and nucleic-acid-only complex interfaces that accepts both experimentally solved and computationally predicted (including AlphaFold3) structures, incorporating AF3-specific confidence/scoring metrics into its interface analysis. It performs distance-based interface characterization with interactive 2D interface maps and RNA/DNA secondary-structure topology plots, plus an interface-based density-zoning feature for evaluating dynamic or ambiguous regions directly within cryo-EM maps. For structural biologists, it functions as a post-prediction/post-solving analysis layer — bridging AlphaFold3-era structure generation with functional interface interpretation that previously required stitching together multiple disparate tools.
bioRxiv · cancer biologyConceptual
A cellular "off switch" halts error-prone DNA repair once it's no longer needed, blocking extra mutations.
When DNA gets damaged, cells have a backup copying system called translesion synthesis (TLS) that lets them push through the damage instead of stalling — but this backup system is sloppy and makes mistakes. Researchers found a protein pair, FBXO44 and RAD18, that acts like a brake: once the danger has passed, FBXO44 tags RAD18 for disposal, shutting the risky repair pathway back down. This shutdown is controlled by p53, the well-known "guardian of the genome" protein, which activates FBXO44 later in the stress response. Without this brake, cells accumulate more mutations, which can fuel cancer — so understanding it could reveal new ways to exploit this vulnerability in tumors.
Technical view
Using transcriptional profiling, genome-wide CRISPR/Cas9 screens for replication-stress sensitivity, and proteomics, the authors identify FBXO44 as a late p53 target gene that terminates translesion DNA synthesis (TLS). FBXO44 acts as an F-box substrate receptor that ubiquitinates RAD18, the E3 ligase responsible for PCNA monoubiquitination that licenses TLS polymerase recruitment, triggering RAD18 turnover during recovery from replication stress. This creates a temporally restrained circuit: p53 activation induces FBXO44 to shut down RAD18-PCNA-Ub signaling once lesion bypass is complete, limiting persistent error-prone synthesis. Loss of this axis is predicted to raise mutagenesis and could be probed as a synthetic-lethal vulnerability in p53-proficient, TLS-dependent tumors.
bioRxiv · physiologyRunnable
A seminal fluid protein throttles sperm's turbo-swim mode by plugging a calcium channel, piece by piece.
After ejaculation, sperm are temporarily "put to sleep" by a seminal fluid protein called semenogelin-1 (SEMG1), which stops them from developing the vigorous whip-like swimming (hyperactivation) needed to fertilize an egg — until later processing frees them up. This study asked how SEMG1 pulls this off, and found it directly blocks a calcium channel called CatSper on the sperm's tail that's essential for that power-swimming behavior. By testing the full protein versus fragments of it, the researchers pinpointed two separate regions of SEMG1 that each help shut the channel down. Understanding this molecular brake could explain natural fertility control and inspire new non-hormonal contraceptive approaches.
Technical view
The authors used recombinant full-length mouse SEMG1 (Q32-G375) and truncated fragments with patch-clamp electrophysiology to show SEMG1 directly inhibits CatSper, the sperm-specific principal calcium channel required for hyperactivated motility, at physiologically relevant concentrations. Because NH4Cl-induced alkalinization failed to rescue hyperactivation, the inhibitory mechanism acts downstream of the pH-dependent CatSper activation step rather than blocking capacitation-associated alkalinization itself. Domain-mapping with truncated constructs identified two distinct functional regions each contributing to CatSper current suppression, suggesting a multi-site inhibitory mechanism. This establishes CatSper as a direct pharmacological target of seminal plasma regulation, offering a template for CatSper-modulating non-hormonal contraceptives or fertility diagnostics.
bioRxiv · plant biologyConceptual
Doubling a plant's chromosomes makes it much easier to break its "no self-fertilizing" rule.
Many flowering plants have a genetic self-incompatibility system that stops them from fertilizing themselves, which keeps genetic diversity high — but scientists have noticed that plants with doubled chromosome sets (tetraploids, versus normal diploids) tend to self-fertilize more often. This study used mathematical models and computer simulations to test how easily a new "self-compatible" mutation can invade and spread in populations with one versus two chromosome copies. They found the self-incompatibility system is inherently more fragile in tetraploids, and that the pecking order of which genetic variants dominate over others strongly affects how fast the system collapses. This helps explain plant evolution and crop breeding patterns, including why genome duplication (common in plant history) so often coincides with a shift toward self-fertilization.
Technical view
Using analytical population-genetic models and individual-based simulations, the authors compare invasion dynamics of a self-compatible (SC) allele into sporophytic self-incompatibility (SSI) systems in diploid versus tetraploid populations, under both codominant and hierarchically-dominant SI allele architectures. The core result: SSI breakdown is systematically easier in tetraploids than diploids, and increasing the dominance rank of the invading SC allele further accelerates its fixation. The dominance-class scenario shows that segregation and expression patterns unique to autotetraploid genetics (more allele combinations per genotype) weaken effective self-recognition. This provides a quantitative framework linking ploidy-driven dominance/segregation changes to the empirically observed correlation between polyploidy and elevated selfing rates in angiosperms.
bioRxiv · plant biologyConceptual
Leaf pores meant to release water double as bacterial front doors — and as flood barriers against infection.
Plant leaves have tiny water-releasing structures at their edges called hydathodes, which ooze out excess water (guttation) — but they're also a favorite entry point for certain leaf-attacking bacteria. Researchers engineered Arabidopsis plants with fewer hydathodes and found something surprising: instead of being protected, these plants got internally waterlogged and let bacteria multiply out of control by sneaking in through other pores called stomata. Physically clogging hydathodes caused the same waterlogging and infection boost in both Arabidopsis and cauliflower. The takeaway: hydathodes aren't just infection risks, they're essential drainage valves that prevent leaf tissue from flooding, and that flooding is what lets bacteria run rampant — showing a plant's internal plumbing is a core part of its immune defense.
Technical view
Hydathodes are xylem-connected structures at Arabidopsis leaf margins that mediate guttation and serve as known infection portals for vascular pathogens like Xanthomonas campestris. The authors show Arabidopsis mutants with reduced hydathode numbers develop spontaneous mesophyll water-soaking upon infection and support unexpectedly large bacterial populations, driven by pathogen entry through stomata and proliferation directly in the water-soaked mesophyll niche rather than the vasculature. Physical occlusion of hydathodes reproduced both water-soaking and enhanced bacterial growth in Arabidopsis and cauliflower, causally linking hydraulic dysfunction to loss of nonvascular tissue resistance. This establishes leaf hydraulic regulation as an active component of "water immunity," suggesting hydathode function or water-soaking resistance as a novel breeding target for bacterial disease resistance.
bioRxiv · systems biologyBuildable
A fat-cell "burn switch" that turns fat into heat also seems to shield the heart from a fatty diet.
Obesity-related heart disease is a huge health problem, and one hope for treatment lies in brown and "beige" fat — special fat tissue that burns calories as heat instead of storing them, activated through a receptor called beta3AR. This study genetically removed beta3AR specifically from fat cells in mice, then fed them a high-fat, high-sugar diet, with some treated with a drug that normally activates this receptor, to test whether the receptor is truly necessary for fat-burning's heart-protective benefits. Proving the fat cells themselves (not some other organ) are responsible for protecting the heart opens the door to drugs that specifically target fat tissue to prevent obesity-related heart damage. This matters because current treatments for obesity-linked heart problems aren't very effective, and this points to a specific druggable pathway.
Technical view
The authors used adipocyte-specific beta3-adrenergic receptor (beta3AR) knockout mice challenged with a high-fat-sucrose (HF-S) diet, with and without the selective beta3AR agonist CL316,243, to test whether adipocyte beta3AR is required for beige/brown fat-mediated cardiometabolic protection. Beta3AR normally drives adipose tissue lipolysis and BAT thermogenesis, and pharmacological activation induces beiging of white adipose depots — a pathway of therapeutic interest given BAT's limited abundance in aged/obese humans. The genetic deletion isolates adipocyte-autonomous beta3AR signaling from systemic or cardiac-intrinsic drug effects, directly testing whether cardiac metabolic/structural protection depends on this receptor in fat cells specifically. Results should clarify whether beta3AR agonists' cardioprotective effects in obesity are mediated via adipose remodeling, informing whether adipose-targeted versus cardiac-targeted agonism is the better drug strategy.
bioRxiv · systems biologyBuildable
Scientists dunked cells carrying mystery transporter proteins into human blood to catch what they actually shuttle around.
Solute carrier proteins (SLCs) are a huge family of "doorways" in cell membranes that shuttle nutrients, drugs, and waste in and out of cells, but for many of them we don't know what molecules they actually carry — unidentified locks without known keys. Researchers put frog egg cells (a classic tool for testing one protein at a time) engineered to make a single human SLC transporter each into human blood serum, packed with thousands of real biological molecules, then used a sensitive chemical detection method (mass spectrometry) to see which molecules vanished from outside and appeared inside the cell, or vice versa. This let them match five specific transporters to the substances they actually move, "deorphanizing" proteins whose job was previously unknown. Since these proteins govern nutrient absorption, drug delivery, and disease, mapping what each one moves could reveal new drug targets or explain unwanted drug interactions.
Technical view
The authors developed a Xenopus oocyte-based screening platform in which oocytes heterologously expressing individual human SLC transporters are incubated in human serum — a complex, physiologically relevant metabolite library — followed by paired untargeted LC-MS/MS profiling of both intracellular extracts and surrounding medium to detect metabolite depletion/accumulation signatures indicative of transport activity. Applied to five transporters (SLC10A2, SLC10A6, SLC13A2, SLC16A10, SLC46A1), the method detected characteristic exchange signatures, with automated feature annotation refined by manual chromatographic/spectral review to assign putative substrates. This sidesteps the need for pre-selected candidate substrate panels, enabling unbiased deorphanization against physiological metabolite complexity rather than synthetic buffers. The platform is generalizable to any cloneable SLC and could scale to map substrate spectra across the ~400-member human SLC superfamily, informing drug-transporter interaction and nutrient biology studies.
bioRxiv · systems biologyBuildable
A two-gene injection eased arthritis pain and joint damage in both mice and full-size horses.
Osteoarthritis causes chronic joint pain and disability, and there's currently no treatment that actually slows the disease rather than just masking symptoms. Because the disease involves multiple problems at once — inflammation and breakdown of cartilage-protecting cells — researchers built a gene therapy delivering two therapeutic genes at once (one to calm inflammation, one to support joint-cushioning cells) via a viral carrier injected directly into the joint. They tested this in both mice and horses, which is notable because horse joints are much closer in size and mechanics to human joints, making it a far stronger real-world test than mice alone. The treatment improved joint structure, movement, and pain, and even calmed inflammation-related pain signaling in the nerve clusters carrying pain messages from the joint — suggesting it could become a long-lasting, disease-modifying treatment for arthritis pain in humans.
Technical view
The therapy uses a high-capacity (helper-dependent) adenoviral vector co-expressing two transgenes — IL-1Ra (an interleukin-1 receptor antagonist targeting inflammation) and PRG4/lubricin (supporting chondrocyte health and cartilage lubrication) — delivered via intra-articular injection. Efficacy was demonstrated across both murine and equine osteoarthritis models, with the equine model providing large-animal, biomechanically human-relevant validation uncommon in OA gene therapy studies. Beyond local joint outcomes (functional, structural, pain metrics), treatment normalized inflammatory gene/protein signatures in joint tissue and in the dorsal root ganglia (DRG) housing joint-innervating sensory neurons, indicating a peripheral neuro-immune mechanism for pain reversal rather than purely local anti-inflammatory action. The dual-transgene, single-vector, intra-articular design and cross-species efficacy data position this as a translatable disease-modifying OA candidate ready for further large-animal/clinical-stage development.
bioRxiv · systems biologyBuildable
Breeding genetically mixed mice and scanning their liver proteins maps the hidden circuitry behind fatty liver disease.
Metabolic dysfunction-associated steatotic liver disease (MASLD, commonly called fatty liver disease) affects an enormous share of adults worldwide, but treatments are limited because scientists don't fully understand the tangled web of genes and proteins driving it. To untangle this, researchers cross-bred four mouse strains that vary in liver disease susceptibility, producing hundreds of genetically diverse offspring, then measured thousands of liver proteins in each mouse alongside its genetic makeup and disease symptoms. By statistically linking specific genetic variants to specific protein levels (quantitative trait loci, or QTLs), they built a map of which genes directly control which proteins, and which of those connections ripple out to affect disease-related traits. This gene-protein-phenotype network gives researchers a roadmap of candidate genes and proteins to test as potential drug targets for fatty liver disease.
Technical view
The authors generated a four-way founder cross of 444 F2 mice with genetically diverse liver disease susceptibility, then performed deep quantitative proteomic profiling of livers paired with genotyping to map protein quantitative trait loci (pQTLs). They identified QTLs for 2,652 proteins across more than 4,000 unique genomic loci, distinguishing cis-acting (local, likely direct genetic control) from trans-acting (distal, likely network-mediated) regulatory loci. Integration of proteomic, genomic, and phenotypic data enabled construction of gene-protein-phenotype networks, nominating candidate regulatory genes and proteins underlying MASLD trait variation. This resource-scale pQTL dataset provides a systems-genetics framework and candidate gene list other researchers can mine for causal driver validation, functional follow-up, or cross-referencing against human MASLD GWAS/proteomics data.
bioRxiv · zoologyConceptual
A frog's liver keeps a seasonal diary, and its cells write the first draft.
This study follows a small Brazilian treefrog through a full year to see how its liver changes with the seasons. Researchers looked at four levels of the liver at once: tiny chemical stores inside cells, the shape of individual cells, how the tissue as a whole is arranged, and the size of the whole organ relative to the body. The idea they're testing is whether change ripples outward in order — starting at the smallest, fastest-reacting level (inside cells) and only later showing up at the whole-body level. Understanding this hierarchy matters because it tells biologists how animals sense and buffer environmental swings like wet and dry seasons, which is increasingly relevant as climates shift unpredictably.
Technical view
The authors sampled 40-68 wild adult male Dendropsophus minutus across an annual cycle and quantified four hepatic phenotypic modules — intracellular histochemistry (pigment/glycogen stores), cellular morphometry, tissue-level volumetric composition (hepatocytes, sinusoids, melanomacrophage centres, portal structures), and organismal indices (liver mass, body condition) — to test for a predictable temporal response hierarchy across organizational levels. The core hypothesis is that lower organizational levels (intracellular/cellular) exhibit faster, more immediate seasonal responses than higher levels (tissue/organismal), which would lag or integrate cumulative change. This design offers a replicable multi-level framework for other ectotherm field studies aiming to disentangle rate-dependent physiological plasticity from mere seasonal correlation.
bioRxiv · neuroscienceConceptual
Your brain seems to read the 'grammar' of a scene, not just list the objects in it.
When you look at a photo, you don't just notice a dog and a ball separately — you understand the dog is chasing the ball. This study asks whether the brain's visual areas actually encode that kind of relationship, not just a checklist of objects and words. Researchers fed the brain (via detailed brain scans while people viewed images) either full descriptive sentences about scenes or the same words scrambled into a meaningless jumble, then checked which one better matched brain activity. The full, structured sentences predicted brain responses better, especially for busy, relationship-rich scenes — and an AI model trained on both language and images did a better job explaining this than a vision-only AI. It matters because it suggests our sense of a coherent scene is built into visual perception itself, not bolted on afterward by language.
Technical view
Using 7T fMRI from the Natural Scenes Dataset, the authors built encoding models relating cortical responses to narrative scene descriptions versus word-order-scrambled lexical controls that preserve content words but destroy compositional syntax. Intact narratives predicted high-level visual cortex responses better than scrambled controls, with the advantage scaling with a scene's compositional richness, indicating the region encodes relational/compositional structure beyond a bag-of-words object list. A language-aligned vision model (trained with both visual and linguistic supervision) outperformed a self-supervised vision-only model at capturing this structure, suggesting language-alignment during training instills representations closer to how visual cortex organizes scene relations — a testable target for future multimodal model-brain alignment work.
bioRxiv · immunologyConceptual
A stressed-out cell factory inside immune cells may be secretly fueling psoriasis flare-ups.
Psoriasis is a skin condition where immune cells and skin cells send inflammatory signals back and forth in a vicious cycle. This research shows that a common psoriasis-triggering chemical stresses out a cell's internal protein-folding factory (the endoplasmic reticulum, or ER) inside immune cells called dendritic cells, causing contact points to form between the ER and the cell's energy-producing mitochondria. That stress response boosts production of an inflammatory signal (IL-23) and also leaks out mitochondrial DNA and calcium, which further rev up inflammation through a separate alarm system. Meanwhile skin cells under the same stress make an antimicrobial protein that, together with the leaked DNA, activates yet another set of immune cells — building a self-reinforcing inflammatory loop. Mapping this loop matters because it reveals new points, beyond current psoriasis drugs, where treatment could interrupt the cycle.
Technical view
In a murine imiquimod (IMQ)-induced psoriasis-like dermatitis model, IMQ drives ER-mitochondria contact site (MAM) formation and UPR activation in dendritic cells, which enhances IL-23 expression independently of but convergent with TLR7/MyD88 signaling; concurrently, elevated cytosolic Ca2+ activates the NLRP3 inflammasome, releasing mitochondrial DNA. Keratinocytes exposed to IMQ upregulate UPR-dependent genes including the antimicrobial peptide Defb14/mBD14, and extracellular mtDNA plus mBD14 cooperatively engage plasmacytoid dendritic cells via TLR9, closing an amplification loop. This positions ER stress/UPR and MAM signaling as a mechanistic node upstream of IL-23 and TLR9 activation, offering candidate targets (e.g., UPR inhibitors, MAM disruptors) for combination therapy alongside existing IL-23-axis biologics like the gene mentioned Gelsolin counteracting this circuit.
bioRxiv · immunologyConceptual
Deliberately messy vaccines might out-evolve fast-mutating viruses like COVID.
Viruses like the one causing COVID keep changing shape to dodge our immune defenses, so vaccines built for one version can lose effectiveness. This project tries a counterintuitive fix: instead of targeting the virus's usual weak spots, build an mRNA vaccine (the same technology behind many COVID shots) that deliberately mixes in many different, less-common versions of the virus's surface protein. The goal is to nudge the immune system toward attacking parts of the virus that are less likely to mutate away, a strategy the researchers call 'rare epitope suppression.' They analyzed two years of public COVID genetic sequencing data to find the sites on the virus that vary the most, then designed their 'wobble vaccine' around that diversity. If it works, it could mean vaccines that stay effective longer against a shape-shifting virus, cutting down the need for constant reformulation.
Technical view
The authors mined public SARS-CoV-2 sequence data from the pandemic's first two years to identify high-diversity epitope sites, then designed mRNA-based 'wobble vaccines' — complex antigen pools incorporating multiple variant sequences at those sites — to apply 'rare epitope suppression' (RES), redirecting humoral immunity away from hypervariable immunodominant epitopes toward more conserved regions. The claim is that this pool-based antigen design broadens antibody targeting and improves cross-strain neutralization compared to single-strain vaccines. This is a platform-level approach that could be replicated for other rapidly evolving pathogens (e.g., influenza) by substituting pathogen-specific diversity-mapped antigen sets into the same mRNA delivery framework.
bioRxiv · molecular biologyConceptual
Cells caught rewriting DNA damage also relabel it with the same chemical tags it had before.
Our DNA carries not just the genetic code but also chemical 'sticky notes' called methylation marks that tell cells which genes to use — and these marks need to be faithfully copied every time DNA is repaired or replicated, or cells can lose track of their identity. This study looks at what happens to those marks when DNA gets damaged by UV light (like sunburn-causing rays) and then repaired. The researchers found that cells actually preserve most of the original marks during repair, and they identified the specific molecular crew responsible: two 'marking' enzymes get recruited to damage sites, guided by a helper protein and the repair machinery itself. They also found that fresh copies of a structural protein called a histone, deposited right at the damage site, help recruit this whole marking crew. This matters because losing methylation marks incorrectly is linked to cancer and other diseases, so understanding how cells protect this memory during repair could reveal new angles on disease risk.
Technical view
Using sequencing, imaging, and proteomics in mammalian cells subjected to UV damage, the authors show that DNA methylation is largely preserved during nucleotide excision repair-associated synthesis, and they identify recruitment of DNMT1 and DNMT3A to repair sites, driven by the DNMT1 cofactor UHRF1 together with UV damage repair endonucleases. They further demonstrate a mechanistic link to chromatin dynamics: newly deposited H3.3 histones at damage sites help recruit this methylation-maintenance machinery, extending the known replication-fork paradigm (where UHRF1/DNMT1 maintain methylation) to a DNA-damage-repair context. This establishes damage-repair synthesis as a second genomic context requiring active methylation maintenance, suggesting UHRF1/DNMT1/H3.3 dynamics as candidate targets for probing epigenetic instability in damage-prone or repair-deficient tissues.
bioRxiv · molecular biologyBuildable
One shot of gene therapy calms an arthritic knee for a while — then needs a disguised sequel.
Osteoarthritis, the wear-and-tear joint disease, has no treatments that actually slow its progression — only ones that manage pain. This study tests a gene-therapy approach in mice with injury-induced knee arthritis: injecting a modified virus directly into the joint that delivers instructions for cells to make an anti-inflammatory protein (IL-1Ra) which blocks a key driver of joint damage. A single injection helps early on, protecting cartilage and joint function, but as the disease progresses further, that protection fades. The problem is that the body's immune system learns to recognize and block the virus, so a second dose of the same type doesn't work well — but the researchers show that switching to a different 'disguise' (viral serotype) for the repeat dose restores its effectiveness. This points toward a practical strategy for giving repeated joint gene therapy over the long course of a chronic disease.
Technical view
In the murine ACL-transection model of post-traumatic osteoarthritis, single intra-articular injection of high-capacity adenovirus (HCAd5) delivering NFkB-responsive IL-1Ra provides structural and functional benefit in early-stage disease but fails to sustain cartilage protection as OA progresses, and repeat dosing with the same HCAd5 serotype is blunted by pre-existing anti-vector immunity. The authors demonstrate that serotype-switching for the repeat injection restores effective transduction and therapeutic benefit, establishing a sequential heterologous-serotype dosing strategy to overcome anti-adenoviral immunity in a chronic, progressive disease context. This has direct translational relevance for gene therapy dosing regimens in OA and other conditions requiring repeated local adenoviral delivery, where serotype rotation could be built into treatment protocols.
bioRxiv · molecular biologyBuildable
DNA's traffic-control proteins hold hands across distance, not just at close range.
Inside every cell, DNA is folded into loops and neighborhoods, and special 'insulator' proteins act like fence posts marking where one neighborhood ends and another begins. This study looks at a fence-post protein called BEAF in fruit flies and asks how it teams up with three helper proteins to do its job. Using lab techniques that detect when two proteins physically touch or work together in living cells, the researchers found that two of the three helpers (Pzg and Chro) can interact with BEAF even when not directly touching — suggesting they connect through a longer-range mechanism — while the third helper (CP190) does not behave this way. Pinpointing exactly which parts of each protein are responsible for these interactions helps explain how the genome's 3D organization is built and maintained, which matters because that folding affects which genes get switched on or off.
Technical view
Using yeast two-hybrid assays, in vitro pull-downs with bacterially expressed proteins, and bimolecular fluorescence complementation (BiFC) in Drosophila S2 cells, the authors mapped the minimal interacting domains between the insulator protein BEAF and three co-insulator proteins (CP190, Pzg, Chro). They find that Pzg and Chro, unlike CP190, can engage BEAF via interactions detectable at a distance (consistent with BiFC signal indicating proximity without requiring direct stable binding captured by pull-down), and functional assays in transfected S2 cells reveal distinct roles for each co-insulator in BEAF-dependent chromatin organization/transcriptional regulation. This domain-mapping data provides concrete interaction interfaces that could be mutated or disrupted in follow-up studies to dissect BEAF-dependent TAD boundary formation and its transcriptional consequences.
bioRxiv · molecular biologyBuildable
Mapping which proteins rush to a DNA break reveals a hidden repair 'org chart' with switchboard operators.
When DNA breaks, several 'sensor' proteins rush to the damage site to kickstart repair, but how they coordinate the many other cellular jobs that need to pause or adjust hasn't been clear. This study uses a labeling technique that tags every protein sitting near three key sensors as repair unfolds over time, essentially taking repeated snapshots of the neighborhood around the break from the moment of damage through recovery. The three sensors share a common core repair crew but also each attract their own specialized partners — one leans toward RNA and chromatin tasks, another toward the chromosome tips and protein-building machinery, and the third toward the actual DNA-copying and recombination work. The researchers also found 'connector' proteins that link these otherwise separate work crews together, and removing one such connector, Nucleolin, disrupted the coordination. This matters because it reveals how a cell's damage response is wired into a larger network rather than being an isolated repair job.
Technical view
SPARK-ID is a proximity-labeling method used with SIRT6, Ku80, and MRE11 as baits to capture time-resolved, chromatin-associated interactomes from DSB formation through recovery. The three sensors share an enriched core repair interactome while diverging in temporally specialized partners: SIRT6 toward RNA/chromatin regulation, Ku80 toward telomere-associated and translational programs, and MRE11 toward recombination and DNA synthesis. Modularity analysis identified functional modules linked by 'connector' proteins, with Nucleolin bridging DNA repair, RNA-metabolism, and nucleolar modules; Nucleolin depletion perturbs this cross-module coordination, implicating it as a hub for integrating repair with broader nuclear processes. The dataset and proximity-labeling framework offer a template for mapping temporally dynamic interactomes around other DNA damage response factors or other transient chromatin events.
bioRxiv · molecular biologyConceptual
Mapping where a newly approved lung-scarring drug's target actually sits in scleroderma tissue.
Systemic sclerosis (SSc) is an autoimmune disease that causes hardening and scarring of skin, lungs, and blood vessels. A drug called nerandomilast, just approved for a related lung-scarring disease, works by blocking a protein called PDE4B, which is thought to calm immune cells, reduce scarring, and protect blood vessel linings. But nobody had carefully checked where PDE4B is actually turned up or down in the different tissues and cell types affected by scleroderma. The researchers used gene-reading techniques (single-cell RNA sequencing) and antibody-based staining to map PDE4B across lung, blood immune cells, and skin from SSc patients. This groundwork helps predict which patients or tissues might actually respond if doctors try repurposing this drug for scleroderma.
Technical view
The study systematically profiles PDE4B expression in SSc using single-cell RNA-seq (transcript level) alongside immunohistochemistry, immunofluorescence, and multiplexed immunofluorescence (protein level) across lung, PBMCs, and skin. PDE4B was consistently dysregulated in immune cell populations, but direction and magnitude of dysregulation varied by tissue compartment, suggesting cell-type- and organ-specific regulation rather than uniform pathway activation. This compartmental map provides a mechanistic rationale and biomarker framework for trialing PDE4B inhibitors like nerandomilast in SSc, and could guide patient stratification by matching target expression to tissue involvement.
bioRxiv · molecular biologyConceptual
A cellular protein-sorting machine quietly edits how a virus builds its outer shell.
Viruses like Sindbis virus (a relative of viruses causing diseases like chikungunya) build their outer envelope proteins using the host cell's own protein-folding machinery, a channel in the cell's membrane called a translocon. The virus has a trick called 'ribosomal frameshifting,' where the cell's protein-building machinery briefly shifts reading frame mid-gene, producing two different versions of a protein from one piece of genetic code. This study finds that a specific segment of the viral protein interacts with a recently discovered version of the translocon (the 'multipass translocon'), and that removing pieces of this multipass machine changes how often the frameshifting trick happens. In short, the virus is hijacking a subtle detail of the cell's assembly line to fine-tune how its own building-block proteins turn out, revealing a new angle on how viruses exploit host cell machinery.
Technical view
Sindbis virus's structural polyprotein uses a hydrophobic segment corresponding to E2's second transmembrane domain to engage translocon components cotranslationally, modulating -1 programmed ribosomal frameshifting (-1PRF) that controls polyprotein stoichiometry. Building on prior work linking this segment to translocon interactions, the authors knock out components of the recently characterized multipass translocon (MPT) and show this increases -1PRF efficiency, implicating MPT recruitment as a regulatory checkpoint for viral protein biogenesis. This links host ER quality-control machinery directly to viral gene expression control, suggesting MPT components as potential targets for antiviral strategies aimed at disrupting alphavirus structural protein maturation.
bioRxiv · cell biologyBuildable
Hunting for a drug that could jam a cell-migration 'motor' linked to cancer and kidney disease.
Cells move around the body by activating internal machinery, and a protein pairing called ELMO1 and DOCK2 acts like a switch that turns on this movement machinery (via a protein called Rac1). This pairing matters in kidney disease, cancer spread, gut infections, and inflammation, but no drug has ever been made to block it, partly because scientists only recently figured out its 3D shape. This paper uses computer simulations, essentially virtual test-tubes, to search through databases of small molecules and predict which ones might wedge into the ELMO1/DOCK2 interface and break up the pair. It's an early, purely computational first step toward a drug that doesn't exist yet, checking whether the target is even 'druggable' before anyone synthesizes or tests a real compound.
Technical view
Leveraging the newly solved ELMO1/DOCK2 complex structure, the authors perform structure-based virtual screening to identify small molecules predicted to disrupt this protein-protein interaction interface that activates Rac1 GTPase signaling. They apply molecular dynamics (MD) simulations and free energy landscape (FEL) analysis to assess binding stability and druggability of candidate hits at the interface. This establishes a computational pipeline and starting hit list that could be handed off for experimental validation (binding assays, cellular Rac1 activity assays) as a first-in-class ELMO1/DOCK2 inhibitor program.
bioRxiv · cell biologyBuildable
Tracking a cancer-causing virus's hideouts inside the throat and gut of infected baboons.
HTLV-1 is a virus spread through blood and breastfeeding that can cause leukemia and nerve inflammation in people, but scientists don't fully know where in the body it hides and replicates, especially along the mouth-to-gut route it may use to spread, because human tissue samples are hard to get. This study instead uses baboons naturally infected with STLV-1, a very close relative of the human virus, and examines tissues like tonsils, stomach, and other parts of the mouth and gut using different PCR methods (lab techniques that detect and count tiny amounts of viral genetic material). By comparing how well different PCR approaches measure a viral gene called Tax across these tissues, the researchers build a more complete map of where the virus lives in the body, filling in a gap that's nearly impossible to study directly in humans.
Technical view
The study quantifies STLV-1 Tax expression across oropharyngeal and gastrointestinal tissues (tonsils, stomach, and others) from naturally infected olive baboons (Papio anubis), a validated animal model for HTLV-1, using and comparing multiple PCR-based quantification methods. This addresses the scarcity of human tissue data on HTLV-1 distribution along suspected oral transmission routes. The methodological comparison of PCR approaches for Tax detection provides a benchmarked protocol other researchers could adopt for tissue-level retroviral quantification in NHP models, informing future studies of HTLV-1/STLV-1 tissue tropism and transmission biology.
bioRxiv · cell biologyConceptual
Human lungs may heal a different way than mouse lungs, using cells mice don't even have.
The tiny air sacs in your lungs where oxygen exchange happens are lined by a workhorse cell type (AT1) that can't repair itself, so it normally relies on a helper cell type (AT2) to regenerate it after injury, at least in mice. But humans and other large mammals have extra airway structures and cell types near the air sacs that mice simply lack. Using lung tissue grown from human stem cells in a dish (organoids) and comparing it computationally to real tissue, the researchers found that in humans, a different set of airway cells can directly regenerate the oxygen-exchanging cells, skipping the mouse-style AT2 pathway. They also found that cells resembling a harmful, scar-associated cell type seen in pulmonary fibrosis patients show up as a normal, faster step in this human repair process rather than always being a sign of disease. This challenges assumptions drawn from mouse research and could reshape how scientists think about fibrotic lung disease.
Technical view
Using human pluripotent stem cell-derived lung organoids combined with comparative computational analysis (likely single-cell transcriptomics and trajectory inference), the authors show that terminal and respiratory bronchiole epithelial cells, structures present in humans but absent in mice, can directly regenerate AT1 alveolar cells without transiting through the AT2-derived KRT8+ intermediate state established in mouse injury models. They further find that cells resembling profibrotic 'aberrant basaloid cells,' previously associated with pathological fibrosis, arise as a faster, physiological intermediate in this human-specific regenerative trajectory. This reframes aberrant basaloid-like states as a normal repair checkpoint rather than purely a disease marker, with implications for interpreting single-cell data from IPF/pulmonary fibrosis patient lungs and for building more human-relevant organoid injury-repair models.
bioRxiv · cell biologyConceptual
A pomegranate-derived compound may shield nerve cells from sugar-driven mitochondrial damage.
Diabetic neuropathy is nerve damage caused by long-term high blood sugar, and most current treatments just try to control blood sugar rather than directly protecting the nerves themselves from damage. Corilagin is a natural antioxidant compound (found in plants like pomegranate) that hasn't previously been tested against this kind of sugar-induced nerve injury. Researchers exposed human nerve-like cells in a dish to very high glucose levels to mimic diabetes, which damaged the cells' energy-producing mitochondria and triggered cell death, then tested whether Corilagin could prevent this damage. They found it restored a key cellular energy-and-stress-response pathway (AMPK-SIRT1-PGC1α-TFAM), essentially helping the cell's power plants function and repair themselves again, protecting the cells from dying under high-sugar stress.
Technical view
In an in vitro model, SH-SY5Y human neuroblastoma cells exposed to high glucose (50 mM, 24h) exhibited reduced viability, elevated intracellular and mitochondrial ROS, depleted glutathione, and increased apoptosis, hallmark features of diabetic neuropathy-associated mitochondrial dysfunction. Corilagin treatment reversed these effects, with mechanistic data pointing to restoration of the AMPK-SIRT1-PGC1α-TFAM axis, a core regulatory pathway for mitochondrial biogenesis and antioxidant defense. This positions Corilagin as a candidate neuroprotective compound acting via mitochondrial biogenesis pathways rather than glycemic control, providing a mechanistic starting point for in vivo diabetic neuropathy models and structure-activity studies of ellagitannin derivatives.
bioRxiv · cell biologyConceptual
A moss 'feels' injury through flickering calcium sparks that kickstart its self-healing.
When plants get physically wounded, it can trigger cells nearby to reprogram themselves and regenerate new tissue, but how a mechanical injury gets translated into that cellular decision has been unclear. Using live video microscopy on the moss Physcomitrium patens, researchers tracked calcium ions (Ca2+), which cells use as rapid internal signals, and found that wounding triggers an initial wave of calcium followed by a strange, long-lasting 'flashing' pattern of random calcium sparks that specifically occurs in cells right next to the wound and persists for hours. They showed this is triggered by physical deformation of the cell's outer membrane opening calcium channels, and that even just stretching the membrane with osmotic stress (without actual injury) can trigger a similar rapid spike. This builds a timeline connecting physical force on a cell to the calcium signals that seem to set regeneration in motion.
Technical view
Using live-cell calcium imaging in Physcomitrium patens, the authors map a spatiotemporal Ca2+ signaling framework following mechanical wounding: an initial propagating Ca2+ wave, followed by two distinct secondary response modes, including a novel stochastic 'flashing' Ca2+ signature confined to wound-adjacent cells that persists for hours. They show membrane deformation from wounding activates plasma membrane Ca2+ influx, and that osmotic stress-induced membrane tension alone can trigger rapid Ca2+ spikes without the spatially restricted flashing pattern, and pharmacological channel blockade experiments further dissect the mechanosensitive Ca2+ influx pathway. This establishes a testable model linking mechanosensation to regenerative cell fate reprogramming, providing specific Ca2+ dynamic signatures and channel targets that could be probed in other regenerating plant or even animal wound-response systems.
bioRxiv · cell biologyConceptual
Sperm cells have a built-in 'delete' button for DNA damage that mice use during their final transformation.
Sperm cells go through a dramatic makeover in their final stage of development, called spermatids, reshaping themselves over roughly a week in flies or two weeks in humans, and by this point they've already lost the backup chromosome copies most cells use to repair DNA damage. That makes this a risky window for passing on genetic damage to offspring, yet how the body safeguards genome quality during this stage wasn't well understood. Using fruit flies zapped with radiation to damage DNA, researchers found that the sperm-maturation process itself gets specifically disrupted to eliminate spermatids with damaged genomes, essentially a built-in quality-control checkpoint that culls bad cells rather than trying to fix them. They also identified a new role for a specific DNA-packaging protein variant (histone H2Av) in carrying out this elimination process, revealing a dedicated genome-surveillance system unique to this vulnerable stage of sperm development.
Technical view
Post-meiotic spermatids lack sister chromatids or homologous chromosomes, precluding homology-directed repair, yet must maintain genome integrity over an extended maturation period. Using γ-irradiation of Drosophila to induce DNA damage, the authors show that spermiogenesis is actively rerouted to eliminate damaged haploid nuclei rather than repair them, and identify a non-canonical role for the histone variant H2Av in mediating this elimination pathway. This describes a haploid-stage-specific genome quality-control checkpoint distinct from canonical DNA damage response pathways, suggesting H2Av-dependent nuclear elimination machinery as a target for future studies of male germline mutation load and fertility, with likely conservation given the extended haploid phase in human spermatid maturation.
bioRxiv · developmental biologyConceptual
Two ancient genes may explain why human brains grew bigger and more complex than other primates'.
Scientists compared brain stem cells from humans and rhesus monkeys to find genes uniquely active in human neural progenitor cells — the cells that build the brain's outer layer during development. They found human cells lean on programs that keep them dividing and acting like versatile 'radial glia' scaffolding cells, plus genes that carefully manage cell division itself. Two gene-regulating proteins stood out: ZNF90, found only in apes, and OVOL2, which is ancient and shared across many species. By testing what these two proteins actually control inside lab-grown mini-brains (organoids), the researchers could see how they shape the number and behavior of brain-building cells — a clue to what makes human brain development distinct.
Technical view
The study profiles NPC transcriptomes across humans and rhesus macaques, an outgroup for hominoid comparisons, and identifies genes enriched in human NPCs tied to radial glial identity, proliferative capacity, and sister chromatid segregation. Two zinc-finger transcription factors emerge from this comparison: ape-restricted ZNF90 and deeply conserved OVOL2. The authors map genome-wide binding sites and transcriptional targets of both factors and perturb them in cerebral organoids to assay downstream effects on NPC dynamics. This establishes a testable regulatory axis for comparative work on human-specific features of cortical progenitor expansion.
bioRxiv · developmental biologyConceptual
A brain region that builds specialized 'relay' neurons works almost the same way in mice and humans.
Deep in the developing cerebellum sits a strip of tissue called the rhombic lip, which produces several types of brain cells including unipolar brush cells (UBCs) — neurons that relay and amplify signals. When UBC development goes wrong, it's linked to a birth condition called Dandy-Walker Syndrome and to a childhood brain tumor, but mice haven't been great stand-ins for studying this. Researchers tracked where these cells form and how they mature in both mice and humans, using fluorescent tagging and gene-by-gene sequencing of individual cells, while also switching off a key gene called Eomes to see what breaks. They found the mouse rhombic lip is organized into the same distinct zones as the human one, with a persistent pool of dividing precursor cells, and that Eomes directs the genetic programs guiding these cells to mature and migrate — validating mice as a workable model for these diseases.
Technical view
The authors characterize UBC development in the rhombic lip (RL) using multiplex immunofluorescence and single-cell RNA-seq in wild-type and conditional Eomes-knockout mice, benchmarking against human RL architecture. They find the murine RL is molecularly compartmentalized like the human RL, with an abundant, persistent population of cycling EOMES+ UBC progenitors extending postnatally. Eomes loss disrupts the transcriptional networks driving UBC differentiation and migration, though some processes appear Eomes-independent. This establishes cross-species conservation of RL/UBC biology, supporting mouse conditional-knockout models for studying Dandy-Walker Syndrome and medulloblastoma origins.
bioRxiv · ecologyConceptual
Plants don't just trade off 'fast growth vs. tough survival' leaf-by-leaf — they commit to it whole-body.
Botanists have long noticed that plant traits — like leaf thickness or root density — tend to fall along a spectrum from 'acquisitive' (grow fast, live cheap) to 'conservative' (grow slow, built to last), and this pattern shows up separately in leaves and in roots. This paper asks whether that pattern is real or just a statistical illusion caused by other hidden factors, like plant size or habitat, sneaking into the data. Using a more careful math technique that strips out those confounding influences, the researchers show the fast-vs-tough tradeoff isn't a separate story for leaves and another for roots — it's really one strategy that governs the whole plant at once. This reshapes how ecologists think about classifying and predicting plant strategies across the globe.
Technical view
Prior work using dimension-reduction (e.g., PCA) on trait matrices reported organ-specific acquisitive-conservative axes in leaves and roots, but such analyses are vulnerable to third-variable confounds (e.g., plant size, phylogeny) inflating apparent independent structure. The authors apply a dimension-reduction method that explicitly controls for these confounders across a broad trait dataset. The controlled analysis collapses the ostensibly separate leaf and root spectra into a single acquisitive-conservative axis operating at the whole-plant level. This challenges the organ-modular framing common in plant economics spectrum literature and suggests trait-based ecological models should integrate above- and below-ground traits jointly rather than treating them as independent axes.
bioRxiv · evolutionary biologyConceptual
Bee-flowers and bird-flowers keep interbreeding for 85+ years, yet somehow stay genetically distinct species.
Two wildflowers in the Sierra Nevada mountains — one pollinated by bees, one by hummingbirds — look and behave very differently, and biologists have long assumed that difference is what keeps them from merging into one species where they overlap. This study tests that assumption in a spot where the two flowers have been crossbreeding for at least 85 years. The team measured flower traits, mapped genes, and modeled how bees and birds actually perceive flower color to see whether the color difference (controlled by a couple of pigment genes) is really what pollinators use to stay loyal to one species over the other. Surprisingly, the genetic barrier that keeps the species separate doesn't line up neatly with the flower differences pollinators can see — suggesting something other than simple pollinator preference is keeping these species apart.
Technical view
The study examines a long-standing hybrid zone between Penstemon davidsonii (bee-pollination syndrome) and P. newberryi (bird-pollination syndrome) to test classic pollinator-driven ecological speciation models. Despite persistent hybridization over 85+ years, the parent taxa retain strong multivariate trait divergence and genomic differentiation. Floral hue maps to a single genomic locus containing two candidate anthocyanin-pathway genes with large phenotypic effects, and pollinator visual modeling assesses whether bees/birds can discriminate this variation. The key finding — that genomic signatures of reproductive isolation are decoupled from floral trait divergence — implies barriers other than pollinator-mediated assortative mating maintain species boundaries here, complicating simple pollination-syndrome speciation narratives.