Biology subjects

Fang, Y.

Publications and source records attributed to Fang, Y..

At least 55 records · Page 3Linked to original sources

bioRxiv2025

An extensive forward genetic screen identifies the HWS-AGO1 axis as pivotal for target mimicry-mediated miRNA degradation in Arabidopsis

Target RNAs have emerged as key regulators of miRNA stability, thereby influencing development and physiological processes in both plants and animals. The F-box protein HAWAIIAN SKIRT (HWS) has been characterized as a crucial factor in targeted miRNA degradation in plants (pTMD), a process triggered by a specific type of target RNA called target mimicry. However, the precise mechanism by which HWS functions is still poorly understood. We previously established a genetic reporter system based on Short Tandem Target Mimicry of miR160 (STTM160) triggered miR160 degradation, resulting in pleiotropic developmental defects that are easy to monitor. Here, through an extensive forward genetic screen, we identified fourteen additional hws alleles that near-completely restored STTM160-induced developmental defects, highlighting a central role for HWS in pTMD. Intriguingly, we discovered two adjacent amino acid substitutions (R421K and G422D) in the PAZ domain of AGO1 that significantly suppressed the STTM160 phenotype. Similar to HWS dysfunction, the AGO1 R421K substitution caused a significant retention of target mimicry RNAs in AGO1 immunoprecipitates, suggesting that the R421 residue of AGO1 may cooperate with HWS for the clearance of AGO1-miRNA-target mimicry complexes. Although the R/G mutations only impacted a small set of endogenous miRNA levels, they were sufficient to rescue the developmental defects caused by HWS overexpression (HWS-OE), suggesting that the developmental abnormalities caused by HWS-OE largely depend on the AGO1-miRNA pathway. Taken together, our findings provide a solid genetic evidence for the coordination of HWS and AGO1 in pTMD.

plant biology↗

bioRxiv2025

HGS+ enlarged vesicular compartment serves as site for coronavirus assembly at later infection stage

The precise site of coronavirus assembly remains poorly characterized. In this study, we observed that coronavirus infection induces the host factor hepatocyte growth factor-regulated tyrosine kinase substrate (HGS) to form distinct HGS enlarged vesicular compartments at later infection stage. Confocal and live-cell super-resolution microscopy showed that viral structural proteins colocalize with these HGS enlarged vesicular compartments. Correspondingly, APEX2-based electron microscopy (APEX2-EM) and immuno-EM analyses confirmed the presence of assembled virions within these unique HGS compartments, identifying them as sites of virion assembly. This was further supported by cryogenic correlated light and electron microscopy (cryo-CLEM), which captured ongoing virion formation occurring within HGS enlarged vesicles. Crucially, whole cell volume EM revealed that HGS deficiency abolishes these vesicular compartments and markedly reduces assembled virions. Lastly, we demonstrated that HGS vesicular compartments are rearranged from Golgi and endosome/lysosome by coronavirus infection. Together, these findings establish that coronavirus-induced HGS vesicular compartments function as essential platforms for virion assembly at later infection stage.

microbiology↗

bioRxiv2025

Genomic insights into adaptation strategies and microevolutionary forces of novel non-AOA Nitrososphaeria in acid mine drainage ecosystems

The class Nitrososphaeria is best known for ammonia-oxidizing archaea (AOA), yet deeply branching non-AOA lineages remain poorly characterized, leaving a critical gap in our understanding of the groups early evolution and ecological diversification. Herein, we recovered 44 non-AOA Nitrososphaeria metagenome-assembled genomes (MAGs) from acid mine drainage (AMD) sediments in diverse metal mines, representing two novel genera within the family UBA164, Acidarchaeum and Thermosulfuris. A meta-analysis of 251 AMD-associated metagenomes showed that these potentially thermophilic lineages are globally distributed but typically rare, with local peaks ([~]6.6%) at sites such as Fankou. Metabolic reconstruction suggested a facultatively anaerobic, mixotrophic lifestyle capable of CO oxidation and sulfur reduction, and extensive acid- and heavy-metal resistance mediated primarily by ether-linked archaeal lipids, ion efflux systems, and enzymatic reduction. Genus-specific traits include dissimilatory sulfate reduction in Thermosulfuris and urea utilization in Acidarchaeum, illuminating distinct ecological niches for them. Population-genomic analyses reveal low homologous recombination and pervasive purifying selection in these non-AOA populations, together with local relaxation of selection and elevated diversity, the former being correlated with geochemical stressors (notably copper), pointing to long-term, geochemically driven adaptation. Overall, these findings provide insights into the biodiversity, ecophysiology, and evolutionary dynamics of non-AOA Nitrososphaeria. IMPORTANCEMembers of the class Nitrososphaeria that oxidize ammonia are central to the global nitrogen cycle, yet deep-branching lineages that lack this metabolism remain poorly explored, obscuring their early evolutionary trajectory. Here, we identify two new genera of non-ammonia-oxidizing Nitrososphaeria from acid mine drainage ecosystems and show that they recur globally in these acidic, metal-rich, oligotrophic habitats. Genomic analyses reveal adaptations for survival in harsh environments and genus-specific metabolic traits, suggesting distinct ecological strategies. Evolutionary analyses further indicate that these lineages are highly specialized, with population-genomic patterns consistent with long-term adaptation to geochemical conditions. This work sheds light on the biodiversity and evolutionary constraints of early-diverging lineages of Nitrososphaeria.

microbiology↗

bioRxiv2025

Repressed expression of nucleoporins and importins impairs plant defense against an infectious noncoding RNA

Plant pathogens threaten global food security and cause substantial annual economic losses. Of particular concern are host jumps, in which pathogens expand their host range to new species, often resulting in sudden and difficult-to-control disease outbreaks. However, the ability to anticipate such events remains limited by an incomplete understanding of pathogen adaptability and the mechanisms governing nonhost resistance. Here, we show that temperature modulates the infectivity and host range of potato spindle tuber viroid (PSTVd), a pathogenic noncoding RNA that severely impacts solanaceous crops such as potato and tomato. Using in vivo single-molecule RNA structure probing, we found that higher temperatures drive PSTVd into a more uniform RNA conformation associated with enhanced infectivity in tomato. Concurrently, elevated temperature suppresses key host defense pathways, including RNA silencing and NPR1-mediated immunity. Notably, these conditions enable PSTVd to overcome nonhost resistance and establish infection in Arabidopsis thaliana. Our findings reveal that elevated temperature promotes PSTVd host expansion through multiple coordinated mechanisms, linking changes in pathogen behavior with increased host susceptibility, and suggest that ongoing climate warming may heighten the risk of viroid host jumps.

plant biology↗

bioRxiv2025

Fast Multi-objective RNA Optimization with Autoregressive Reinforcement Learning

Codon optimization is essential in mRNA vaccine development, while existing tools face limitations in the computational efficiency, sequence diversity and universality. To address these challenges, we develop RNAJog (RNA Joint Optimization with autoregressive Generative model), a framework integrating autoregressive generation with reinforcement learning to optimize codon sequences for minimum free energy (MFE), codon adaptation index (CAI) and GC content, even enabling sequence design without requiring annotated training data. Evaluations in both in silico and wet-lab experiments have confirmed RNAJogs effectiveness and efficiency, with two orders of magnitude faster than traditional algorithm (LinearDesign) for long RNA sequence and about a 10-fold increase in antibody titer compared to the wild-type mRNA for Influenza virus hemagglutinin (HA) mRNA vaccine design in mouse. RNAJog also supports biological constraints for sequence optimization. Using this feature, we minimized m6A modification motifs in Bmp2 coding sequence for enhancing the translational efficiency and RNA stability, which are validated in cell-based experiments.

bioinformatics↗

bioRxiv2025

Surgical Removal of Visceral Adipose Tissue has Therapeutic Benefit in Male APPNL-F Mice

PurposeVisceral white adipose tissue (vWAT) accumulation causes systemic inflammation, insulin resistance, metabolic syndrome, and senescent cell accumulation that are risk factors for Alzheimers disease (AD). Visceral fat removal (VFR) improves metabolism and reduces pro-inflammatory cytokines. We hypothesized that VFR removal in AD mice would improve metabolism and cognition. MethodsMale and female APPNL-F mice underwent sham or vWAT surgical resection (periovarian or epididymal and perirenal) at 4 (pre-symptomatic) and 16 (symptomatic) months of age to understand interventional and therapeutic effects, respectively. At 18 months of age, glucose metabolism and novel object recognition (NOR) memory were assayed followed by assessment of body composition and tissue-specific markers of metabolism, cell senescence, inflammation, or amyloid accumulation. ResultsMale and female APPNL-F mice showed distinct VFR responses. In pre-symptomatic males, increased vWAT lipolysis and hepatic lipogenesis led to ectopic liver lipid accumulation, with reduced adiponectin and leptin, elevated visfatin, and impaired glucose metabolism. Symptomatic males showed reduced vWAT lipogenesis, enhanced hepatic lipolysis, glycolysis, and glycogenesis, lowering liver lipids and improving insulin sensitivity. Only symptomatic males improved NOR, linked to elevated hippocampal learning and memory markers. Female vWAT reaccumulation was due to increased lipogenesis and lower lipolysis. Pre-symptomatic females had lower hepatic lipogenesis, while glycolysis and glycogenesis declined with disease progression. Hippocampal senescence and inflammation were elevated early in the disease that persisted symptomatically. ConclusionsSex-specific differences in glucose and lipid metabolism and lipid accumulation underlie the divergent responses to VFR in APPNL-F mice, with symptomatic males showing the only beneficial outcomes in metabolism and cognition. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/669175v2_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@6ec644org.highwire.dtl.DTLVardef@9ad821org.highwire.dtl.DTLVardef@1e37775org.highwire.dtl.DTLVardef@b7a558_HPS_FORMAT_FIGEXP M_FIG C_FIG Male and female APPNL-F mice exhibited distinct VFR responses to AD progression. In males, early disease stages were marked by vWAT lipolysis and hepatic lipid accumulation with metabolic dysfunction, while symptomatic stages showed a metabolic shift that improved insulin sensitivity and NOR performance. In contrast, females displayed progressive vWAT reaccumulation, reduced hepatic metabolism, and persistent hippocampal senescence and inflammation from early stages onward.

neuroscience↗

bioRxiv2025

Spatiotemporal lineage mapping of tumor immune escape with eTRACER

The plasticity-first hypothesis posits that phenotypic plasticity emerges first in novel environments, followed by (epi)genetic changes that stabilize adaptive phenotypes. Whether tumor evolution follows this model, and how non-genetic mechanisms sustain long-term therapeutic resistance, remain unclear. Here, we develop eTRACER, an endogenously targeted, high-resolution and spatially-resolved CRISPR-Cas9 lineage-tracing system, to study tumor adaptation during longitudinal CD8+ T cell-mediated immunotherapy. Integrated clonal and single-cell transcriptomic analyses show that tumor immune evasion is governed by clonal state composition rather than clonal identity, arguing against selection from pre-existing genetic heterogeneity. Spatiotemporal lineage tracing reveals highly reversible state transitions prior to therapy, followed by consolidated epithelial-mesenchymal transition (EMT) during therapy. Single-cell multiomics identifies AP-1 as a key regulator of EMT stabilization and its inhibition enhances tumor sensitivity to immune killing. Together, these findings show that tumor plasticity precedes stable immune evasion, revealing an AP-1-centered mechanism underlying plasticity-first tumor evolution.

cancer biology↗

bioRxiv2025

Bottlebrush Polymer Conjugates for Enhanced Antisense Oligonucleotide Therapy in Myotonic Dystrophy Type 1

Oligonucleotides are a promising genetic medicine for myotonic dystrophy type 1 (DM1), the most common adult-onset muscular dystrophy. However, poor muscle distribution of nucleic acid drugs after systemic administration has hindered drug development, and no curative treatment exists. Additionally, DM1 pathology requires drug localization to the nucleus, where pathogenic mutant RNA is trapped, posing challenges after endocytosis and endosomal escape. Here, we show that a locked nucleic acid oligonucleotide targeting mutant CUGexp RNA tracts, conjugated to a bottlebrush polymer, exhibited improved muscle distribution and potent correction of DM1-associated splicing at low nanomolar doses in a DM1 mouse model. Significant improvements in myotonia, body weight, and grip strength were observed. The conjugates were well tolerated after 12 weeks of weekly intravenous dosing. These results suggest that bottlebrush polymer bioconjugates may overcome key limitations of traditional antisense drugs for muscular dystrophies, with the potential as potent, durable, and cost-efficient DM1 therapies. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/668589v1_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@e3961corg.highwire.dtl.DTLVardef@194225dorg.highwire.dtl.DTLVardef@5c470dorg.highwire.dtl.DTLVardef@3cc46a_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2025

Hybrid peptide DNA nanomaterials enable potent and broad-spectrum virus neutralization

The continued emergence of antigenic drift and drug-resistant viral strains highlights the need for antiviral strategies that deliver robust efficacy, broad subtype coverage, and minimal off-target toxicity. We demonstrate a potent and broad-spectrum strategy that employs hybrid biomaterials of Urumin (a host defense peptide) and a honeycomb (HC) DNA origami through spatially organized multivalent presentation for enhanced antiviral efficacy. Molecular dynamics simulations reveal that Urumin penetrates and destabilizes the hemagglutinin (HA) trimer core, disrupting influenza A viral (IAV) entry. Arranging Urumin in trimeric clusters on the HC enables potent multivalent binding to trimeric HAs on IAV, enhancing antiviral efficacy at nanomolar concentrations, [~]1,000-fold more effective than free Urumin. In vitro assays confirm HC-Urumin outperforms free Urumin in blocking viral entry and preserving cell viability in more IAV subtypes. In vivo studies show that compared to free Urumin, HC-Urumin treatment reduces disease severity, preserves physiological behavior, and decreases mortality in infected mice, while maintaining virus-specific adaptive immune responses without altering humoral immunity. Our study offers an advanced and effective materials platform and strategy for broad-spectrum, low-dose intervention against human and animal IAVs, which can be adapted to combat other viruses by patterning corresponding host defense peptides on custom designed DNA nanostructures.

bioengineering↗

bioRxiv2025

Human induced pluripotent stem cell-derived microglia with a CX3CR1-V249I genetic variant exhibit dysfunctional phenotypes and modulate neuronal growth and function

The involvement of microglia in neurodegenerative diseases has drawn increasing attention, as many genetic risk factors are preferentially expressed in microglia. Microglial fractalkine receptor (CX3CR1) signaling regulates many key microglial functions, and the CX3CR1-V249I single nucleotide polymorphism (SNP) has been associated with increased risk for multiple neurodegenerative conditions, including Alzheimers disease, yet its functional consequences in human microglia remain unexplored. In this study, we generated iPSC-derived human microglia-like cells (hMGLs) and found that the CX3CR1-V249I variant increased susceptibility to starvation-induced cell death, reduced amyloid-beta uptake, altered microglial morphology, and impaired migration, with more pronounced effects in homozygous cells. Co-culture with neurons demonstrated that hMGLs with the CX3CR1-V249I variant misregulated neuronal properties, including abnormal neuronal growth as well as an induction of neuronal hyperexcitability. These findings highlight the critical role of CX3CR1 in regulating microglial function and implicate the V249I variant in driving pathogenic microglial states relevant to neurodegeneration.

neuroscience↗

bioRxiv2025

The anaerobic WOR-3 Bacteria: Hydrogenotrophic metabolism and unique carbon fixation via Archaeal form III RuBisCO

The uncultured WOR-3 phylum is widely distributed in anaerobic environments, including hot springs, marine ecosystems, and hydrothermal vents, yet its ecological roles and metabolic capabilities remain poorly understood. In this study, we analyzed 180 medium- to high-quality metagenome-assembled genomes (MAGs), including 59 newly reconstructed from environmental samples and 121 retrieved from the Genome Taxonomy Database (GTDB). Phylogenetic analyses resolved the WOR-3 lineage into four subgroups (subgroup 1-4). Metabolic reconstruction revealed significant divergence of the carbon, sulfur, nitrogen and hydrogen metabolism pathways among the different subgroups. Subgroup 1 was characterized by fermentative metabolism involving formate and ethanol, and uniquely exhibited potential for carbon fixation via Calvin cycle, as indicated by the presence of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) gene. Notably, WOR-3 RuBisCO is phylogenetically affiliated with archaeal form III, although the carbon fixation pathway follows the canonical bacterial Calvin cycle--a feature of potential evolutionary significance. Subgroup 3 exhibits metabolic versatility, including genes for dissimilatory sulfate reduction, sulfur oxidation, partial denitrification, and fatty acid degradation. In addition, all subgroups harbored key components of hydrogen metabolism, including widespread NiFe hydrogenases and Rnf complexes, supporting H2-dependent electron transfer and energy conservation under anaerobic conditions. Featuring near-universal presence of complexes I and II and frequent occurrence of terminal oxidases (cydAB and coxABC)--suggests a facultative anaerobic lifestyle. Collectively, this study expands the genomic framework for the WOR-3 phylum and provides novel insights into the metabolic versatility and ecological functions of this previously uncharacterized lineage in biogeochemical cycles of carbon, nitrogen, and sulfur. IMPORTANCEThe WOR-3 phylum represents a widespread but poorly understood bacterial lineage inhabiting diverse anaerobic/microaerobic environments. By integrating 180 metagenome-assembled genomes, including 59 newly reconstructed, this study provides the most comprehensive genomic framework to date for WOR-3. Phylogenomic and metabolic analyses revealed four distinct subgroups with divergent capacities for carbon, sulfur, and nitrogen metabolism. Notably, subgroup 1 encodes a complete Calvin-Benson-Bassham (CBB) cycle featuring an archaeal-type form III RuBisCO, suggesting an unusual evolutionary trajectory for carbon fixation in this lineage. Subgroup 3 exhibits versatile metabolic potential, including dissimilatory sulfur metabolism, partial denitrification, and fatty acid degradation, highlighting its possible roles in multiple biogeochemical processes. The widespread presence of hydrogenases and respiratory complexes across all subgroups supports energy conservation under anaerobic or microaerobic conditions. These findings not only expand the taxonomic and functional landscape of the WOR-3 phylum but also offer key insights into its ecological roles in global element cycling.

microbiology↗

bioRxiv2025

Synthetic essentiality of TRAIL/TNFSF10 in VHL-deficient renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive subtype of kidney cancer. Loss of von Hippel-Lindau (VHL) and the consequent activation of hypoxia-inducible factor- (HIF, especially HIF2) plays an essential role in ccRCC initiation and progression. The approved HIF2 inhibitor belzutifan faces the challenge of resistance, presenting an opportunity of co-targeting HIF2 and another vulnerability. This study elucidates the synthetic essentiality of TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) in VHL-deficient ccRCC, uncovering a novel reciprocal regulation between HIF2 and TRAIL. TRAIL was identified as a direct transcriptional target of HIF2 and paradoxically found to be crucial for cell proliferation, primarily by activating the p38 MAPK pathway and facilitating G1/S phase transition. Depletion of endogenous TRAIL or inhibition of HIF2 with belzutifan sensitizes ccRCC cells to recombinant TRAIL, presenting a promising avenue for combination therapy to overcome both TRAIL resistance and belzutifan resistance in treating ccRCC. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=162 SRC="FIGDIR/small/621197v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1d603b9org.highwire.dtl.DTLVardef@18e6dc7org.highwire.dtl.DTLVardef@1c953cdorg.highwire.dtl.DTLVardef@9cd144_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2025

Mechanosensitive Endothelial METTL7A Regulates Internal m7G mRNA Methylation and Protects Against Atherosclerosis

BACKGROUNDInternal N7-methylguanosine (m7G) is a recently identified chemical modification of mammalian mRNA and a component of the epitranscriptome. While the epitranscriptome plays a key role in regulating RNA metabolism and cellular function, the specific contribution of internal m7G to cardiovascular health and disease remains unknown. Atherosclerosis preferentially develops at sites where disturbed blood flow activates endothelial cells, but whether internal m7G and its regulatory machinery influence endothelial mechanotransduction and atherogenesis is unclear. METHODSWe integrated epitranscriptomic profiling, human tissue analysis, genetically modified mouse models, and targeted nanomedicine approaches to investigate the role of Methyltransferase-like protein 7A (METTL7A), a putative internal m7G methyltransferase, in regulating the flow-sensitive endothelial transcriptome and atherosclerosis. Vascular endothelial cells were subjected to well-defined athero-protective and athero-prone flow waveforms in vitro and in vivo. METTL7A function was assessed using RNA sequencing (RNA-seq), liquid chromatography-tandem mass spectrometry (LC-MS/MS), crosslinking immunoprecipitation sequencing (CLIP-seq), RNA stability assays, and a CRISPR-Cas-inspired RNA targeting system (CIRTS). METTL7A expression in human coronary arteries with and without atherosclerosis was evaluated by RNA-seq and immunostaining. In vivo atherosclerosis studies were conducted in both global and endothelial-specific Mettl7a1 knockout mice. Endothelial METTL7A expression was restored using cationic polymer-based nanoparticles delivering CDH5 promoter-driven METTL7A plasmids or VCAM1-targeted lipid nanoparticles delivering N1-methylpseudouridine (m{superscript 1}{Psi})-modified METTL7A mRNA. RESULTSAthero-protective unidirectional flow significantly induced METTL7A expression, which promoted internal m7G methylation of endothelial transcripts, while other major epitranscriptomic marks and cap-associated m7G were not affected by METTL7A. METTL7A preferentially binds to AG-enriched motifs in protein-coding mRNAs and plays a key role in regulating KLF4 and NFKBIA transcripts, enhancing their internal m7G and stability and supporting vascular homeostasis. In contrast, endothelial METTL7A expression was significantly reduced by disturbed blood flow and in human atherosclerotic lesions. Global or endothelial-specific loss of METTL7A exacerbated disturbed flow-induced atherosclerosis in mice, independent of serum lipid levels. Restoration of endothelial METTL7A, via nanoparticle-mediated plasmid or m1{Psi} mRNA delivery, markedly reduced lesion formation in Mettl7a1-/- and ApoE-/- mice. CONCLUSIONSThese findings establish METTL7A as a previously unrecognized mechanosensitive methyltransferase that maintains endothelial homeostasis by stabilizing key anti-inflammatory transcripts, KLF4 and NFKBIA, through internal m7G methylation. Loss of METTL7A disrupts endothelial function and accelerates atherogenesis in response to disturbed flow. Therapeutic restoration of endothelial METTL7A, via targeted nanoparticle-mediated gene or m1{Psi} mRNA delivery, significantly lessens atherosclerosis. Collectively, these results uncover a novel epitranscriptomic mechanism governing vascular health and position METTL7A as a promising target for precision nanomedicine in atherosclerotic cardiovascular disease.

molecular biology↗

bioRxiv2025

Modeling human retinal ganglion cell axonal outgrowth, development, and pathology using pluripotent stem cell-based microfluidic platforms

Retinal ganglion cells (RGCs) are highly compartmentalized cells, with long axons serving as the sole connection between the eye and the brain. RGC degeneration in injury and/or disease also occurs in a compartmentalized manner, with distinct injury responses in axonal and somatodendritic compartments. Thus, the goal of this study was to establish a novel microfluidic-based platform for the analysis of RGC compartmentalization in health and disease states. Human pluripotent stem cell (hPSC)-derived RGCs were seeded into microfluidics, enabling the recruitment and isolation of axons apart from the somatodendritic compartment. Initial studies explored axonal outgrowth and compartmentalization of axons and dendrites. We then compared the differential response of RGCs differentiated from hPSCs carrying the OPTN(E50K) glaucoma mutation with isogenic control RGCs in their respective axonal and somatodendritic compartments, followed by analysis of axonal transport. Further, we explored the axonal transcriptome via RNA-seq, focusing on disease-related axonal differences. Finally, we established models to uniquely orient astrocytes along the axonal compartment combined with modulation of astrocyte reactivity as a pathological feature of neurodegeneration. Overall, RGC culture within microfluidic chips allowed enhanced cell growth and maturation, including long-distance axonal projections and proper compartmentalization, while patient-specific RGCs exhibited axonal outgrowth deficits as well as decreased rate of axonal transport. Finally, the induction of astrocyte reactivity uniquely along the proximal region of RGC axons led to the onset of neurodegenerative phenotypes in RGCs. These results represent the first study to effectively recapitulate the highly compartmentalized properties of hPSC-derived RGCs in healthy and disease states, providing a more physiologically relevant in vitro model for neuronal development and degeneration.

neuroscience↗

bioRxiv2025

Adaptive Asymmetric Adjustment in Affective Evaluation and Reciprocity for Altruistic Behaviors from Exogenous Uncertainty to Certainty

In direct reciprocity, environmentally imposed exogenous uncertainty frequently decouples benefactors altruistic intentions from final outcomes. How do cooperative bonds remain resilient against this inevitable "noise"? Adopting a comprehensive levels-of-analysis framework across eight experiments, we integrate interpersonal paradigms, computational modeling, multivariate fMRI decoding, and third-party social evaluations to uncover a robust "asymmetric adjustment" in beneficiarys affective evaluation and reciprocity under exogenous uncertainty, systematically delineating its cognitive algorithmic rules, neural representations, and adaptive functions in sustaining human cooperation. Specifically, beneficiarys reciprocity amplifies for positive deviations from expectations while buffering against reciprocal reductions from unintended shortfalls. Modeling reveals this computational resilience is governed by an asymmetric intrinsic prosocial bias, extending beyond traditional frameworks of outcome/intention-based evaluation, prediction-error-based social learning, or loss aversion. Supported by theory-of-mind system, this "asymmetric adjustment" is perceived as morally superior to other calculations, thereby serving a critical adaptive function to sustain cooperation amidst the volatility of an uncertain world.

animal behavior and cognition↗

bioRxiv2025

Control of leaflet movement pattern by a novel PP2C phosphatase DLM1 in Medicago truncatula

Sessile plants exhibit diverse movement behaviors that have long intrigued the scientists. The legume plants display a rhythmic leaflet movement pattern characterized by horizontal opening during the day and vertical closure at night. However, the underlying mechanisms remain largely enigmatic. Here, we isolated a mutant designated as dlm1 (downward leaflet movement1) from Medicago truncatula that displays leaflets downward opening during daytime while upward closure at night. Cellular analyses reveal that this aberrant phenotype correlates with abnormal volume changes of motor cells within the pulvinus. DLM1 exhibits high expression level in the motor organ pulvinus and encodes an unreported nuclear-localized PP2C phosphatase. Notably, phylogenetic analysis demonstrates that species exhibiting rhythmic leaflet movements consistently retain DLM1 homologs, suggesting the possibility of its functionally conserved role in regulating leaflets movement pattern. Structural characterization reveals that DLM1 possesses both phosphatase and kinase domains. Functional complementation assays demonstrate that the phosphatase domain is necessary and sufficient for maintaining the leaflet movement pattern. Collectively, our work uncovers a novel PP2C protein that governs the leaflet movement, providing mechanistic insights into this intriguing plant behavior.

plant biology↗

bioRxiv2025

The ORF6 accessory protein contributes to SARS-CoV-2 virulence and pathogenicity in the naturally susceptible feline model of infection

Here the infection dynamics, replication, and pathogenicity of a recombinant virus containing a deletion of ORF6 (rWA1{Delta}ORF6) on the backbone of the highly virulent SARS-CoV-2 WA1 virus (rWA1) were investigated and compared to the parental rWA1 virus. While both rWA1 and rWA1{Delta}ORF6 viruses replicated efficiently in cultured cells, the rWA1{Delta}ORF6 virus produced smaller plaques, suggesting reduced cell-to-cell spread. Luciferase reporter assays revealed immune suppressing effects of ORF6 on interferon and nuclear factor kappa B (NF-{kappa}B) signaling pathways. Pathogenesis assessment in cats revealed that animals inoculated with rWA1 were lethargic and presented with fever on days 2 and 4 post-infection (pi), whereas rWA1{Delta}ORF6-inoculated animals developed subclinical infection. Additionally, animals inoculated with rWA1{Delta}ORF6 presented reduced infectious virus shedding in nasal and oral secretions and broncho-alveolar lavage fluid when compared with the rWA1-inoculated cats. Similarly, the rWA1{Delta}ORF6-inoculated cats presented reduced virus replication in the respiratory tract as evidenced by lower viral loads and reduced lung inflammation on day 3 and 5 pi when compared to rWA1-inoculated animals. Host gene transcriptomic analysis revealed marked differences in differentially expressed genes (DEG) in the nasal turbinate of animals infected with rWA1 when compared to rWA1{Delta}ORF6. Importantly, type I interferon signaling was significantly upregulated in rWA1{Delta}ORF6 infected cats when compared to rWA1-inoculated animals, which is correlated to the reduced replication of rWA1{Delta}ORF6 in the upper and lower respiratory tracts of infected animals. Collectively, these results demonstrate that the SARS-CoV-2 ORF6 is an important virulence determinant of the virus contributing to the modulation of host antiviral immune responses. IMPORTANCESARS-CoV-2 encodes several proteins that inhibit host interferon responses. The accessory protein ORF6 antagonizes interferon signaling by blocking the nucleocytoplasmic trafficking of key transcription factors. In this study, we showed that ORF6 plays an important role in SARS-CoV-2 pathogenesis. While both rWA1 and rWA1{Delta}ORF6 viruses replicated efficiently in cell culture, the rWA1{Delta}ORF6 presented impaired cell-to-spread and reduced innate immune inhibition as compared to the parental rWA1. Pathogenicity study in the feline model revealed an attenuated phenotype of the rWA1{Delta}ORF6 indicating that the ORF6 is a major virulence determinant of SARS-CoV-2. These results also demonstrate that ORF6 contributed to the feline host range of SARS-CoV-2.

microbiology↗

bioRxiv2025

The lysine side chain's swing motion in AapA1 toxin promotes water transport through transmembrane pores

The rising antibiotic resistance of Helicobacter pylori and the emergence of multi-drug-resistant strains pose significant challenges to its eradication. Understanding the molecular mechanisms driving this resistance is critical. This study investigates how AapA1, a toxin protein, may inhibit H. pylori growth and cause morphological changes by forming transmembrane pores in its inner membrane. Using experimental data and molecular dynamics simulations, we analyzed the pore structure and its formation mechanism. Results show that AapA1 forms pores on liposomes and exists stably in the membrane as -helices through different multimers, creating hydrophilic pores of varying sizes. Dynamic oscillation of K16/23 side chains in the membrane affects water transport through these pores, and restricting their movement significantly reduces transport. AapA1 monomers adopt three distinct conformations, with the K16/23 residues showing an up-down swing motion, potentially facilitating accelerated transport of substances. This study provides a new perspective on the dynamic structure-function relationship of AapA1-membrane interaction and highlights the role of positively charged residues in AapA1. Understanding the multimeric AapA1-membrane structure and the mechanism underlying AapA1-induced transmembrane pores is particularly crucial to develop new drugs and treatment options to reduce drug resistance emergence and combat any new emergence development.

biophysics↗