Biology subjects

Ma, M.

Publications and source records attributed to Ma, M..

At least 37 records · Page 2Linked to original sources

bioRxiv2026

Multicopper oxidase mediated single-carbon insertion for skeletal remodeling

Modern drug discovery demands efficient strategies for generating structurally diverse compound libraries. Skeletal editing--a transformative paradigm enabling precise atom-level modifications within molecular frameworks, offers a sustainable alternative to traditional synthetic routes. While carbene insertion-mediated approaches have dominated single-carbon insertion strategies, current methodologies are limited by their reliance on hazardous, unstable carbene precursors and harsh reaction conditions. Herein, we report a multicopper oxidase (MCO)-catalyzed skeletal editing that enables the direct, one-step transformation of phenolic and indole derivatives into functionalized tropones and quinoline analogues through exogenous single-carbon insertion. This platform employs stable and safe nitroalkanes as carbon sources and O2 as the sole terminal oxidant. It accommodates a broad substrate scope and yields products with superior antibacterial activity against to multidrug-resistant strains relative to their parent compounds. This work introduces the first biocatalytic platform for exogenous single-carbon insertion skeletal editing. This sustainable and scalable strategy overcomes key limitations of synthetic approaches, offering efficient skeletal remolding and rapid expansion of bioactive compound libraries. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/714988v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1f1d09borg.highwire.dtl.DTLVardef@b67c65org.highwire.dtl.DTLVardef@a0cd4dorg.highwire.dtl.DTLVardef@106afe5_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2026

An oxytocin-gated circuit from the hypothalamus silences olfactory tubercle neurons to drive prosocial grooming

Spontaneous helping behaviors such as allogrooming are vital for survival in social species, yet their underlying neural mechanisms remain largely unknown. Although oxytocin (OXT) is known to modulate allogrooming, the precise neural circuits, molecular pathways, and sensory drivers remain unclear. Here, using a social emergency paradigm in mice, we show that observer mice selectively allogroom distressed, anesthetized conspecifics, a behavior that is guided by main olfactory system cues and mitigates the demonstrators anxiety. We identify an oxytocinergic circuit from the paraventricular hypothalamus to the medial olfactory tubercle (PVNOXT[->]mOT) that is necessary and sufficient for this helping behavior. In vivo fiber photometry reveals that PVNOXT[->]mOT activity and OXT release are temporally locked to allogrooming initiation. This behavioral effect requires oxytocin receptor (OXTR) signaling specifically on mOT dopamine D1 receptor-expressing neurons, where OXTRs suppress neuronal excitability via G protein-gated inwardly rectifying K+ (GIRK) channels. Disruption of this inhibitory mechanism induces neuronal hyperexcitability and impairs allogrooming, a deficit rescued by restoring GIRK function. These findings define a PVNOXT-mOT circuit for prosocial helping, revealing an oxytocinergic pathway with potential therapeutic relevance for neuropsychiatric disorders characterized by social deficits.

neuroscience↗

bioRxiv2026

Gradient Multinozzle 3D Printing

Direct ink writing is compatible with an expansive materials palette. While enabling diverse applications, this materials versatility brings significant bottlenecks in ink formulation, often requiring the mixing, printing, and testing of dozens to hundreds of ink compositions over the course of a project. To accelerate ink-space exploration, we introduce gradient embedded multinozzle (GEM) printheads that combine the high-throughput parallelized printing of multinozzles with combinatorial ink mixing. These printheads allow simultaneous mixing of two-, three-, and four-input inks which are distributed to printer nozzles to create complex 3D structures with graded compositions of inks. Using a two-way GEM printhead, we vali-date cell compatibility by printing scaffolds containing various concentrations of fibroblasts and observing non-linear compaction behaviours. We next test a three-way GEM multinozzle to print ten compositions of di- and multi-functionalized poly(ethylene-glycol) diacrylate hydrogel tri-leaflet valves, optimizing for stiffness, swelling ratio, and toughness. Our GEM multinozzles are compatible with open-source printers and either pressure- or volume-driven extrusion systems and promise to accelerate iterative ink design and testing.

bioengineering↗

bioRxiv2026

Estimating chronological and brain age using risk-taking behavior under uncertainty

Risky decision-making under uncertainty reflects complex cognitive processes supported by distributed brain networks that are vulnerable to aging. However, it remains unclear whether risk-taking behavior can serve as a behavioral marker of brain aging. In the present study, we combined behavioral tasks, computational modeling, and structural magnetic resonance imaging to investigate the relationship between risky decision-making, chronological age, and brain age. A total of 55 young adults and 112 healthy older adults completed the Iowa Gambling Task (IGT) and the Balloon Analogue Risk Task (BART), along with neuropsychological assessments and neuroimaging scanning. Decision processes were quantified using computational models, including the Value-Plus-Perseveration model and Exponential-Weight Mean-Variance. Brain age was estimated from gray matter volume. The results showed significant age-related alterations in parameters reflecting feedback sensitivity, learning rate, and loss aversion in both tasks. Within older adults, several decision parameters were significantly associated with both chronological age and brain age. Regression analyses further showed that computational parameters significantly predicted chronological age and brain age, whereas traditional cognitive screening measures did not show significant predictive effect. Structural brain analyses indicated that IGT-related parameters were primarily associated with the basal ganglia, while BART-related parameters were linked to a broader network including prefrontal, cingulate, and temporal regions. These findings suggest that computational markers of risk-taking behavior capture subtle age-related changes in cognitive processes and brain deterioration. Therefore, risk-taking parameters may serve as reliable functional markers of brain aging, providing critical insights into the mechanisms underlying successful aging.

neuroscience↗

bioRxiv2026

Transcranial direct current stimulation combined cognitive training modulates risk-taking behavior in older adults

Risk-taking behavior is a complex cognitive function that often declines with aging, contributing to impaired decision-making and reduced quality of life. While transcranial direct current stimulation (tDCS) has shown promising effects in modulating cognitive function, its influence on ecologically valid, complex behaviors like risky decision-making in older adults remains poorly understood. We investigated whether a single-session stimulation over the medial orbitofrontal cortex (MOFC) combined with cognitive training could enhance decision-making in healthy older adults. In a randomized, sham-controlled study, bilateral MOFC stimulation (left/anode, right/cathode) was applied during a training task based on the Iowa Gambling Task. Pre- and post-intervention assessments utilized conventional behavioral measures and the Values-Plus-Perseveration computational model, alongside task-related fMRI to examine MOFC network changes. Compared to sham, tDCS significantly enhanced the ability to distinguish advantageous from disadvantageous options. Modeling analysis revealed stimulation-induced changes in multiple latent components, such as learning rate, loss aversion, and perseveration decay. Generalized Psychophysiological Interaction analysis showed that tDCS reconfigured the MOFC network by reducing fronto-frontal hyper-connectivity and enhancing fronto-striatal connectivity. These behavioral improvements were specifically associated with the left MOFC network targeted by anodal stimulation. Our results provide causal evidence that tDCS can mitigate age-related impairments in risk-taking by reconfiguring MOFC-related networks. These findings advance the mechanistic understanding of tDCS in aging and highlight its potential as an intervention to prevent age-related decline in decision making.

neuroscience↗

bioRxiv2026

Complement Factor H (Y402H) polymorphism for age-related macular degeneration alters retinal lipids

Age-related macular degeneration (AMD), the leading cause of blindness in the elderly, is associated with multiple risk factors and involves death of the retinal pigment epithelium (RPE). We investigated how the Y402H polymorphism of Complement Factor H (CFH) and cigarette smoke extract (CSE), major AMD genetic and environmental risks, affect lipid metabolism in RPE differentiated from induced pluripotent stem cells (iPSC-RPE) that were derived from human donors genotyped for low-risk (LR) or high-risk (HR) CFH. Results from discovery-based (lipidomics, proteomics) and targeted (mitochondrial fatty acid oxidation (FAO)) assays found significant genotype-dependent differences under basal conditions include higher free fatty acids and cholesterol esters in HR cells. CSE induced differences in proteins regulating lipid handling, lipolysis, and inflammation. Lower FAO in HR cells was observed in multiple donors and pairs of parent/isogenic edited lines compared with LR lines. CSE induced lipid accumulation, lipid composition remodeling, and upregulation of proteins involved in lipid synthesis/hydrolysis, production of bioactive lipid mediators, and metabolism of ceramide and cholesterol. These results elucidate putative mechanisms driving pathology in RPE harboring CFH Y402H.

systems biology↗

bioRxiv2025

Chart Builder: An Interactive Tool for User Driven Data Visualization in the Electron Microscopy Data Bank

The cryogenic sample-electron microscopy (cryoEM) field has generated significant amounts of 3D Electron Microscopy (3DEM) volumetric data and associated metadata, now comprehensively archived in the Electron Microscopy Data Bank (EMDB - www.emdatabank.org) and the Electron Microscopy Public Image Archive (EMPIAR - www.empiar.org). Harnessing the full potential of these resources requires robust, flexible, and publicly accessible tools for data exploration, analysis and retrieval. Here, we present Chart Builder, an interactive web-based platform that enables researchers to create customizable, publication-quality visualizations directly from archival metadata, validation assessments, and cross-reference annotations. Chart Builder integrates the same query-driven and flexible Solr search system as EMDB search, into a user interface with tools to assist users to filter, group, and compare data without programming expertise. It supports multiple chart types (including line, bar, area, scatter (2D and 3D), histogram, bubble, pie, geographic and Venn diagrams) with customizable axes, data series, and statistical operators. Users can apply global filters, define temporal, categorical, or custom query-based axes, and explore multi-dimensional relationships interactively. Chart data-points are linked to their underlying datasets, such that visualisation interaction opens entry-level or archive-level search results for inspection and datasets from charts may be exported in several ways. Findability, accessibility, interoperability and reusability of data are facilitated by these direct access and export mechanisms, including HTML embedding, persistent URL sharing and chart/data download options. By combining interactivity and ease of use with up-to-date access to the EMDB and EMPIAR archive metadata, both computational and experimental communities may explore and visualize current metadata and export to formats for further analysis or as publication-ready figures. Chart Builder promotes community-driven data analysis and empowers users to evaluate trends in the biological 3DEM field. Chart Builder is freely accessible and fully integrated into the EMDB website at https://www.ebi.ac.uk/emdb/statistics/builder/.

biophysics↗

bioRxiv2025

Epitope and functional classification of human neutralizing antibodies against SFTSV Gn

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a lethal bunyavirus lacking approved countermeasures. From SFTS survivors, we isolate 84 human monoclonal antibodies (mAbs) against the viral glycoproteins Gn and Gc. Gn-specific mAbs demonstrate superior neutralization breadth and potency compared to the restricted neutralizing activity observed with Gc. Using a high-throughput yeast display deep mutational scanning (DMS) platform, we classify Gn-head mAbs into eight epitope groups, among which four groups (IA, ID, IIIA, IIIB) conferring neutralization. Notably, mAbs BD70-4003 (group IA) and BD70-4017 (group IIIA) exhibit broad neutralization and provide 100% protection in a lethal mouse model. Cryo-EM structural analysis of these mAbs in complex with the Gn-head reveal their binding interfaces, directly validating the epitope residues identified by DMS. Our study delineates the antigenic landscape of SFTSV Gn, identifies potent therapeutic candidates, and establishes DMS coupled with structural validation as a powerful framework for antibody discovery against bunyavirus.

immunology↗

bioRxiv2025

A BCG toxic effector induces mitochondrial DNA compaction to refrain protective immunity

Innate immune memory typically emphasizes nuclear chromatin remodeling that determines transcriptional memory in monocytes and macrophages. Here, we show that compaction of mitochondrial DNA (mtDNA), governed by mitochondrial transcription factor A (TFAM) abundance and mtATP-dependent remodeling, defines the transcriptional and functional state of trained macrophages. While typical pathogen-associated molecular pattern (PAMPs) triggered mtDNA accessibility, Bacillus Calmette-Guerin (BCG) effector PE18 directly interacted with and activated SLC25A5 to reduce mtATP levels, thereby inhibiting TFAM degradation by AFG3L2. Accumulated TFAM restricts mtDNA accessibility, suppressing the transcription of the mtNd1 and thereby reducing mtNd1-mediated mtROS production, which diminishes the trained capacity of macrophages against secondary infections. Notably, BCG{Delta}pe18 maintains macrophages cytokine transcriptional capacity independent of classical nuclear histone modifications. Moreover, BCG{Delta}pe18 provides robust and lifelong protective immunity against Mycobacterium tuberculosis (Mtb) infection. These findings reveal mitochondrial genome as a regulatory entity in trained immunity, and suggest a potential strategy for improving vaccine performance.

immunology↗

bioRxiv2025

Activation of IRF7/ISG15 axis in microglia inhibits NLRP3 Expression and Improves the Prognosis of Ischemia/Reperfusion in Mice

Ischemic stroke is a leading cause of disability and mortality, with neuroinflammation playing a key role in post-stroke injury. The molecular mechanisms remain incompletely defined. This study explored the functions of IRF7 and its downstream target ISG15 in stroke-associated neuroinflammation and prognosis of ischemic stroke. Bioinformatic analysis of transcriptomic datasets from microglia and ischemic brain tissues identified both molecules as hub genes. Their expression was validated in a mouse transient middle cerebral artery occlusion (tMCAO) model and in microglial cultures exposed to oxygen-glucose deprivation/reoxygenation (OGD/R). The effects of these molecules were assessed using siRNA knockdown, conditioned media assays with SY5Y neuronal cells, in vivo overexpression of ISG15, histological and functional assessments. Both IRF7 and ISG15 were significantly upregulated after stroke. IRF7 knockdown reduced ISG15 expression, whereas ISG15 knockdown did not affect IRF7, suggesting a unidirectional regulatory relationship. Conditioned media from microglia treated with siIRF7 or siISG15 increased SY5Y cell mortality, with a stronger effect in the siISG15 group, highlighting neuroprotective role of ISG15. ISG15 knockdown also enhanced microglial migration. Conversely, microglial ISG15 overexpression in vivo promoted a shift toward reduced neuroinflammation, improved neuronal survival, and enhanced functional recovery. Mechanistically, ISG15 stabilized NLRP3 protein but more strongly decreased its mRNA stability through accelerated degradation. These findings demonstrate that the activation of IRF7/ISG15 axis in microglia inhibits NLRP3 Expression and improve the prognosis of ischemia/reperfusion in mice, with ISG15 exerting stronger neuroprotective effects. Targeting microglial ISG15 may offer a promising therapeutic strategy for ischemic stroke. MAIN POINTSO_LIISG15 shows a stronger neuroprotective effect than IRF7 in ischemic stroke. C_LIO_LIISG15 stabilizes NLRP3 protein but more strongly decreases its mRNA stability. C_LIO_LIMicroglial ISG15 overexpression in vivo improves the prognosis of ischemic stroke in mice. C_LI

neuroscience↗

bioRxiv2025

Mutational scanning reveals substrate-assisted autoregulation of the WNT destruction complex

The {beta}-catenin destruction complex (BDC) is a central node in WNT/{beta}-catenin signaling, governing embryonic development and adult tissue homeostasis. Although recognized as a prime therapeutic target in colorectal cancer (CRC) for three decades, its dynamic architecture and biochemical complexity have hindered mechanistic understanding. Here, we systematically mapped the sequence-function landscape of the BDC using tiled base editor screens across four endogenous components--CTNNB1, AXIN1, APC, and GSK3B. Validation studies identified [~]150 previously unreported mutations across these genes that affected WNT/{beta}-catenin signaling. In addition to known cancer-associated mutations, we discovered rare gain-of-function and separation-of-function alleles of AXIN1 and CTNNB1 that provide mechanistic insights into complex assembly and regulation. We describe a region in {beta}-catenin that regulates its binding to TCF/LEF transcription factors and demonstrate that the AXIN1-{beta}-catenin interface is critical for controlling signaling flux through the oncogenic BDC. Mechanistic studies revealed that assembly of the oncogenic BDC is scaffolded by its own substrate {beta}-catenin, establishing an autoregulatory mechanism that represents an unexploited vulnerability in cancers harboring common APC truncations. Our comprehensive mutational resource provides a foundation for understanding WNT/{beta}-catenin signaling mechanisms in health and disease, while revealing strategies for therapeutic intervention in WNT-driven cancers.

biochemistry↗

bioRxiv2025

DART: Deep learning for the Analysis and Reconstruction of Transcriptional dynamics from live-cell imaging data

Transcriptional bursting, characterized by stochastic switching between promoter states, underlies cell-to-cell variability in gene expression. Accurately inferring promoter activity from live-cell imaging data remains challenging because the fluorescence signal at any given point is influenced by the history of promoter states. Here, we present DART (Deep learning for the Analysis and Reconstruction of Transcriptional dynamics), a deep learning framework that infers promoter onand off-states from fluorescence intensity traces, enabling the estimation of activation and inactivation rates and the selection of the most appropriate promoter-switching model. DART utilizes a neural network architecture that combines convolutional neural networks and long short-term memory layers to binarize fluorescence traces. Using extensive synthetic datasets spanning a wide range of transcriptional bursting levels, we demonstrate that DART outperforms current binarization methods, including conventional and augmented hidden Markov models, in both accuracy and robustness. Furthermore, a reanalysis of published experimental data using DART reveals a strong linear coupling between activation and inactivation rates, contradicting previous claims of independence. Our approach provides a powerful and generalizable tool for quantitative analysis of transcriptional kinetics from live-cell imaging data.

bioinformatics↗

bioRxiv2025

Contrasting genomic trajectories of Bartonellaceae symbionts of planthoppers

Symbioses with microorganisms have shaped the nutritional biology and evolution of many insects. For example, several ant clades have adapted to nutrient-poor diets through symbiosis with a specific clade of bacteria in the family Bartonellaceae (Hyphomicrobiales), notorious for also including virulent vertebrate pathogens. Here we show that Bartonellaceae phylogenetically placed within the clade that has only encompassed ant symbionts to date - Candidatus genus Tokpelaia - have established as symbionts in four different clades of planthoppers (Insecta: Hemiptera: Fulgoromorpha). Genome size and contents indicate different levels of integration of these strains into the planthopper host biology and their diverse roles. Symbionts infecting one of the clades have some of the largest genomes among Bartonellaceae, at ca. 2 Mb, two others are under 700 kb, and the fourth is reduced to barely 158 kb. The planthopper-associated Tokpelaia strains with larger genomes, similarly to ant symbionts, encode multiple amino acid and vitamin biosynthesis genes, complementing the degraded nutritional capabilities of their hosts ancient heritable endosymbionts. Strikingly, the smallest Tokpelaia genome lacks any genes linked to essential amino acid biosynthesis, in contrast to all other known insect-associated bacteria with genomes of comparable size. We identified a single vitamin biosynthesis gene and iron-sulfur cluster assembly genes as its only putative contributions to the host biology. Our results broaden the host spectrum of non-pathogenic Bartonellaceae, indicating that they have contributed to nutrition and symbiotic consortium function in diverse diet-restricted host clades. They also highlight an unexpectedly broad range of evolutionary outcomes for this important bacterial group. SignificanceMany insects rely on bacterial partners to overcome nutrient-poor diets, yet the diversity and evolutionary trajectories and outcomes for these associations remain unclear. Our discovery of Bartonellaceae bacteria in planthoppers improves the understanding of the host range of these broadly relevant bacteria best-known as vertebrate pathogens. The finding that these planthopper symbionts generally have the capacity to produce essential amino acids and vitamins relevant to hosts and likely form long-term symbiotic associations agree with the expectations for sap-sucking hemipteran symbionts. However, the breadth of sizes and functions of the newly assembled genomes substantially expand the known range of states for Bartonellaceae, and their evolutionary trajectories. In particular, the identification of a strain with an ultra-reduced genome of only 158kb with no amino acid biosynthetic functions contrasts with all other known insect-symbiotic bacteria with genomes in a similar size range. This study also indicates how symbionts may enable the degeneration, functional loss, and evolution of other bacteria residing in the same host.

ecology↗

bioRxiv2025

Combinatorial action of regulatory systems generates colistin heteroresistance

Heteroresistance is a form of antibiotic resistance in which a minor subpopulation of resistant cells coexists with a majority susceptible population. Colistin heteroresistance is common among Enterobacter cloacae clinical isolates, threatens its utility as a last-line therapeutic, and has become a model with which to understand the fundamental bases of heteroresistance. Despite numerous insights, the mechanism by which phenotypic heterogeneity is generated within the population and leads to colistin heteroresistance has been unclear. Here, using a transposon-based mutagenesis screen, we identify the sigma factor {sigma}E as the source of heterogeneity in population-wide colistin resistance levels. Single-cell tracking experiments revealed that {sigma}E is active in only one percent of the population at baseline, and only those cells with active {sigma}E survive colistin exposure. However, {sigma}E expression and population heterogeneity are insufficient for survival, as a mutant lacking the PhoPQ two-component system controlling lipid A modifications necessary for colistin resistance retains heterogeneity but loses colistin resistance. These findings lead to a new paradigm in heteroresistance, where the combinatorial action of multiple regulatory systems, encompassing a heterogeneity generator and a distinct resistance generator, are required to give rise to colistin heteroresistance.

microbiology↗

bioRxiv2025

High-Resolution Detection of Hidden Antibiotic Resistance with the Dilution-and-Delay (DnD) Susceptibility Assay

Rising rates of antibiotic treatment failure highlight the complexity of resistance mechanisms. While conventional, genetically encoded resistance is well established, recent studies have uncovered widespread non-canonical mechanisms driven by phenotypically insensitive subpopulations hiding in seemingly susceptible populations, such as heteroresistance, persistence or adaptive resistance. These variants are not only clinically significant but also act as evolutionary precursors to fully resistant populations, rendering infections increasingly difficult to control. Yet standard antibiotic susceptibility tests lack the resolution and dynamic range needed to detect this wide spectrum of resistance mechanisms and their evolutionary progression, often misguiding clinical decisions, obscuring mechanisms of failure, and underestimating the true epidemiology of antibiotic resistance. To address these limitations, we introduce the Dilution-and-Delay (DnD) assay--a practical, high-resolution approach that implements two basic principles of bacterial growth in the antibiotic susceptibility testing format. Using well-defined synthetic communities and strains, we demonstrate that the DnD assay quantifies viable cells over more than eight orders of magnitude and detects rare antibiotic-insensitive cells at frequencies as low as 1 in 100 million. It additionally reports the standardized MIC as a secondary output, thereby capturing the average antibiotic response of the majority population and heterogeneity of minority subpopulations within a single assay. We scaled this approach for high-throughput application, classifying [~]120 previously uncharacterized clinical isolates of Klebsiella pneumoniae, Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii--across five antibiotics. This robust, quantitative, and scalable platform opens the door to next-generation antibiotic susceptibility testing, with broad utility in basic research, clinical diagnostics, and epidemiological surveillance. This improved testing will guide evidence-based clinical decisions and prevent the rapid evolution of antibiotic resistance, thereby counteracting the rising rate of treatment failure. SignificanceAntibiotic treatment failure due to inappropriate prescription remains a critical threat to global health. It also accelerates the evolution of resistance, making infection increasingly difficult to control. A key underlying issue is that current antibiotic susceptibility testing lacks the resolution and dynamic range needed to detect a wide range of resistance mechanisms and their evolutionary progression, leading to misinformed clinical decisions. While population analysis profiling (PAP) offers sufficient accuracy, it is too labor-intensive for routine use. Single-cell approaches are technically demanding and resource-intensive. Here, we present a susceptibility testing strategy that preserves the operational efficiency and compatibility of conventional workflows, while dramatically extending their resolution and dynamic range. Our approach is scalable, quantitative, and well-suited for high-throughput applications in both research and clinical settings--closing a critical diagnostic gap in the fight against antibiotic treatment failure.

microbiology↗

bioRxiv2025

Deficiency of Mesencephalic Astrocyte-derived Neurotrophic Factor Aggravates Acute Pancreatitis in Mice

Acute pancreatitis (AP) is a complex and potentially severe inflammatory disorder of the pancreas and is one of the most common causes of gastrointestinal hospitalization. Although environmental risk factors such as alcohol and gallstones are well recognized, only a subset of exposed individuals develop AP, suggesting that intrinsic factors, including genetic susceptibility, influence disease onset and progression. Endoplasmic reticulum (ER) stress has emerged as a key mechanism in AP pathogenesis, because ER is essential for protein synthesis, folding, degradation and secretion (proteostasis). Mesencephalic astrocyte-derived neurotrophic factor (MANF), an ER stress-inducible protein highly expressed in the pancreas, plays a critical role in maintaining proteostasis, yet its involvement in AP remains unclear. To investigate the functional role of MANF in AP, we generated pancreas-specific MANF knockout (MANF-KO) mice using the Cre/loxP system and subjected them to moderate experimental AP, that is caerulein- or alcohol-induced AP in mice. In the caerulein model, MANF deficiency exacerbated pancreatic injury in both sexes, as indicated by increased apoptosis (cleaved caspase-3, caspase-12), ER stress markers (eIF2, p-eIF2, GRP78), inflammation (IL-6, TNF), regenerative activity (Ki67), and pancreatic lipase levels. Notably, male MANF-KO mice exhibited enhanced inflammation (HMGB1), macrophage infiltration (CD68), and oxidative stress (DNP, HNE), which were not observed in females. In the alcoholic AP model, both male and female MANF-KO mice showed increased ER stress (p-IRE1, p-eIF2, GRP78), apoptosis, inflammation, macrophage infiltration, regeneration, and lipase levels, whereas elevated HMGB1 expression and oxidative stress again predominantly occurred in male MANF-KO mice. Together, these findings reveal a critical and sex-specific role for MANF in regulating pancreatic stress responses and inflammatory injury, supporting its potential contribution as a genetic factor in AP pathogenesis.

pathology↗

bioRxiv2025

The Winners Take It All? Evolutionary Success ofH5Nx Reassortants in the 2020-2024 Panzootic

Avian influenza viruses undergo frequent genetic reassortment, which can coincide with phenotypic changes in transmission, pathogenicity, and host species niche. Since 2020, clade 2.3.4.4b H5 high pathogenicity avian influenza viruses (HPAIVs) have driven a global panzootic, causing mass mortality in wild birds, poultry, and, for the first time, repeated spillover infections in a variety of mammalian species. This worldwide resurgence of H5 HPAIV has coincided with a dramatic increase in the number of circulating reassortant strains; however, the scale, impact and drivers of these reassortants remain unclear. Here, we combined statistical and phylodynamic modelling to reconstruct the global evolutionary dynamics of H5Nx viruses across four epizootic seasons (2020-2024). We identified 209 genetically distinct reassortants, stratified into three transmission categories based on their phylogenetic and epidemiological profiles. Accounting for sampling depth and HPAIV incidence, we estimated that reassortants emerged most frequently from Asia, but major reassortants associated with increased host range, inter-seasonal persistence, and long-range dissemination, more frequently emerged from Europe. Altogether, reassortant emergence followed an episodic pattern in which most reassortants were transient, but 2% seeded large clusters of secondary reassortants soon after their own emergence. Statistical modelling revealed that reassortant success was strongly shaped by ecological factors, including sustained circulation in specific wild bird orders and detection across a wider range of host niches. Collectively, our findings uncover global reassortment dynamics in H5 HPAIVs and identify key virological and ecological drivers underpinning the emergence and spread of successful reassortants. These insights support the importance of enhanced surveillance to track evolution of H5 HPAIV and identify traits relevant for consideration in pandemic risk assessment.

evolutionary biology↗

bioRxiv2025

A Continuously Oxygenated Macroencapsulation System Enables High-Density Packing and Delivery of Insulin-Secreting Cells

The encapsulation of insulin-secreting cells within immuno-protective systems holds significant promise for curative treatment of type 1 diabetes without immunosuppression. A major challenge, however, remains the inadequate oxygen tension within the encapsulation systems, which compromises the survival and function of encapsulated cells and necessitates low packing density and impractically large systems to deliver a curative cell mass. In this study, we present a novel cell encapsulation system capable of generating oxygen via the electrolysis of tissue moisture to provide a continuous oxygen supply to densely packed insulin-secreting cells. Our system comprises a miniaturized implantable electrochemical oxygen generator (iEOG) and a scalable cylindrical cell encapsulation pouch, designed in a linear configuration to facilitate minimally invasive implantation and retrieval. The oxygen generation from the system was shown to be precisely controlled, stable, and capable of supporting clinically relevant doses of pancreatic islets. In vitro studies demonstrated that the oxygenated system effectively maintained the viability and function of insulinoma cell aggregates and human pancreatic islets at densities of 60,000 islet equivalents per mL (IEQ/mL) or 4,200 IEQ/cm{superscript 2} under a hypoxic cell culture condition (1% O ). In an allogeneic rat model, the oxygenated systems containing pancreatic islets implanted into the poorly vascularized but clinically attractive subcutaneous space at a density of 60,000 IEQ/mL successfully reversed diabetes for up to about 3 months without the need for immunosuppression, while animals implanted with non-oxygenated systems remained diabetic. Most ([~] 90%) of the pancreatic islets encapsulated in the continuously oxygenated systems were found viable and functional upon retrieval. These findings suggest the feasibility of using continuous oxygenation to support insulin-secreting cells at high loading densities in subcutaneous space, enabling the development of an encapsulation system with clinically practical dimensions.

bioengineering↗