Biology subjects

Mao, Y.

Publications and source records attributed to Mao, Y..

At least 73 records · Page 4Linked to original sources

bioRxiv2025

AdapToR: Adaptive Topological Regression for quantitative structure-activity relationship modeling

Quantitative structure-activity relationship (QSAR) modeling has become a critical tool in drug design. Recently proposed Topological Regression (TR), a computationally efficient and highly interpretable QSAR model that maps distances in the chemical domain to distances in the activity domain, has shown predictive performance comparable to state-of-the-art deep learning-based models. However, TRs dependence on simple random sampling-based anchor selection and utilization of radial basis function for response reconstruction constrain its interpretability and predictive capacity. To address these limitations, we propose Adaptive Topological Regression (AdapToR) with adaptive anchor selection and optimization-based reconstruction. We evaluated AdapToR on the NCI60 GI50 dataset, which consists of over 50,000 drug responses across 60 human cancer cell lines, and compared its performance to Transformer CNN, Graph Transformer, TR, and other baseline models. The results demonstrate that AdapToR outperforms competing QSAR models for drug response prediction with significantly lower computational cost and greater interpretability as compared to deep learning-based models.

bioinformatics↗

bioRxiv2025

ZBP1 Senses Splicing Aberration through Z-RNA to promote Cell Death

RNA splicing, a highly regulated process performed by the spliceosome, is crucial for eukaryotic gene expression and cellular function. Numerous cellular stresses including oncogenic insults dysregulate RNA splicing, often provoking inflammatory responses and cell death. However, the molecular signal produced by spliceosome aberration and how cell sensed and respond to it remain elusive. Here we show that spliceosome inhibition induces the widespread formation of unique, left-handed nucleic acids, Z-form nucleic acids (Z-NAs) from the nucleus. These Z-NAs were double-stranded RNA (dsRNA), rather than DNA-RNA hybrids, that were predominantly derived from transcripts of mis-spliced intronic RNA. Spliceosome inhibition induced the egress of these Z-RNA from the nucleus to the cytoplasm in an active manner. Sensing of the accumulation of Z-RNA in the cytosol by the host sensor ZBP1 triggered cell death, mainly for RIPK3-MLKL dependent necroptosis. Collectively, these findings delineate a previously uncharacterized mechanism in which Z-NA sensing by ZBP1 responds to global aberrations of RNA splicing to trigger inflammatory cell death.

cell biology↗

bioRxiv2025

Pioneering New Breeding Pathways with 3PaTec: Unlocking the Power of Polyspermy-Induced Triparentage for Sustainable Crop Development

Over the last few centuries, advancements in plant breeding have revolutionized agriculture, driving significant increases in global food production. Polyploidy, the increase in chromosome copies, can positively affect plant performance and is assumed to have played a critical role in the domestication of crop plants. Polyploidy is thought to be primarily caused by sperm that, due to meiotic aberrations, deliver unreduced chromosome sets. We have recently identified an alternative pathway to polyploidization by demonstrating that polyspermy, the fertilization of an egg cell by more than one sperm, occurs in planta and results in viable triploid plants. Capitalizing on a novel high-throughput polyspermy detection tool, we have shown that polyspermy involving two pollen donors can generate plants with three parents, one mother and two fathers. This 3PaTec technology not only speeds up breeding processes through an instant combination of beneficial traits from three parents; it also allows selective polyploidization of the egg cell, thereby bypassing the central cell-derived embryo-nourishing endosperm, a major hybridization barrier. Here, we further explore the genetic and developmental factors influencing polyspermy and show that the frequency of polyspermy and triparental plant formation varies among ecotypes and depends on pollen availability, suggesting that polyspermy is an adaptive trait. Additionally, we extend the application of 3PaTec to crops by successfully generating triparental sugar beet in-field using a wind pollination strategy. Our findings highlight the potential of 3PaTec for major crop plants. This innovative breeding technology does not rely on genetic engineering, requiring minimal technical expertise and infrastructure. As a result, it is highly accessible to a wide range of users, contributing to the democratization of plant breeding by empowering individuals from all backgrounds to collaborate and contribute to developing resilient and sustainable crops.

plant biology↗

bioRxiv2025

RamEx: An R package for high-throughput microbial ramanome analyses with accurate quality assessment

Microbial single-cell Raman spectroscopy (SCRS) has emerged as a powerful tool for label-free phenotyping, enabling rapid characterization of microbial diversity, metabolic states, and functional interactions within complex communities. However, high-throughput SCRS datasets often contain spectral anomalies from noise and fluorescence interference, which obscure microbial signatures and hinder accurate classification. Robust algorithms for outlier detection and microbial ramanome analysis remain underdeveloped. Here, we introduce RamEx, an R package specifically designed for high-throughput microbial ramanome analyses with robust quality control and phenotypic classification. At the core of RamEx is the Iterative Convolutional Outlier Detection (ICOD) algorithm, which dynamically detects spectral anomalies without requiring predefined thresholds. Benchmarking on both simulated and real microbial datasets--including pathogenic bacteria, probiotic strains, and yeast fermentation populations--demonstrated that ICOD achieves an F1 score of 0.97 on simulated datasets and 0.74 on real datasets, outperforming existing approaches by at least 19.8%. Beyond anomaly detection, RamEx provides a modular and scalable workflow for microbial phenotype differentiation, taxonomic marker identification, metabolic fingerprinting, and intra-population heterogeneity analysis. It integrates Raman-based species-specific biomarkers, enabling precise classification of microbial communities and facilitating functional trait mapping at the single-cell level. To support large-scale studies, RamEx incorporates C++ acceleration, GPU parallelization, and optimized memory management, enabling the rapid processing of over one million microbial spectra within an hour. By bridging the gap between high-throughput Raman-based microbial phenotyping and computational analysis, RamEx provides a comprehensive toolkit for exploring microbial ecology, metabolic interactions, and antibiotic susceptibility at the single-cell resolution. RamEx is freely available under the MIT license at https://github.com/qibebt-bioinfo/RamEx.

bioinformatics↗

bioRxiv2025

Rapaprotin is Activated by an Endopeptidase to Disassemble 26S Proteasome

The 19S regulatory particle (RP) associates with the 20S core particle (CP) to form the 26S proteasome, an evolutionarily conserved holoenzyme that plays key roles in both physiological and pathological processes. Proteasome inhibitors that target the catalytic subunits within the 20S have proven to be valuable research tools and therapeutics for various cancers. Herein we report the discovery of rapaprotin, a 26S proteasome assembly inhibitor from our natural product-inspired hybrid macrocycle rapafucin library. Rapaprotin induces apoptosis in both myeloma and leukemia cell lines. Genome-wide CRISPR-Cas9 screen identified a cytosolic enzyme, prolyl endopeptidase (PREP) that is required for the pro-apoptotic activity of rapaprotin. Further mechanistic studies revealed that rapaprotin acts as a molecular transformer, changing from an inactive cyclic form into an active linear form, rapaprotin-L, upon PREP cleavage, to block 26S proteasome activity. Time-resolved cryogenic electron microscopy (cryo-EM) revealed that rapaprotin-L induces dissociation of the 19S RP from the 26S holoenzyme, which was verified in cells. Furthermore, rapaprotin exhibits a marked synergistic effect with FDA-approved proteasome inhibitors and resensitizes drug-resistant multiple myeloma cells from patients to bortezomib. Taken together, these results suggest that rapaprotin is a new chemical tool to probe the dynamics of the 26S proteasome assembly and a promising anticancer drug lead.

pharmacology and toxicology↗

bioRxiv2025

mTOR regulates Wnt signaling to promote tension-mediated lens vesicle closure

Lens vesicle closure is a pivotal event in ocular morphogenesis, and its disruption underlies Peters anomaly, a leading congenital cause of corneal opacity. Here, we elucidate a mechanistic hierarchy in which mTOR-Wnt signaling orchestrates cytoskeletal tension to drive this process. Conditional ablation of mTOR in the lens ectoderm induces aberrant corneal-lenticular stalk formation and transdifferentiation of the ciliary margin into neural retina. mTOR inhibition suppresses Wnt3 expression, and Wnt3 displayed a similar lens stalk phenotype, positioning mTOR as an upstream regulator of Wnt ligand production. Complete ablation of lens-derived Wnt ligands via deletion of the Wnt transporter Wls exacerbates developmental defects, triggering anterior lens herniation and ciliary margin development failure. Disruption of {beta}-catenin-mediated Wnt signaling or dual deletion of Wnt co-receptors Lrp5/6 in lens ectoderm similarly prevents vesicle closure, recapitulating lens herniation. Strikingly, Rac1 deletion rescues corneal-lenticular stalk phenotypes in mTOR, Wls, and {beta}-catenin mutants, directly linking Wnt effectors to cytoskeletal remodeling. Our findings establish an mTOR-Wnt-Rac1 signaling axis as the core regulator of cytoskeletal tension required for lens vesicle closure.

developmental biology↗

bioRxiv2025

Centromeres in the thermotolerant yeast K. marxianusmediate attachment to a single microtubule

Eukaryotic chromosome segregation requires spindle microtubules to attach to chromosomes through kinetochores. The chromosomal locus that mediates kinetochore assembly is the centromere and is epigenetically specified in most organisms by a centromeric histone H3 variant called CENP-A. An exception to this is budding yeast which have short, sequenced-defined point centromeres. In S. cerevisiae, a single CENP-A nucleosome is formed at the centromere and is sufficient for kinetochore assembly. The thermophilic budding yeast Kluyveromyces marxianus also has a point centromere but its length is nearly double the S. cerevisiae centromere and the number of centromeric nucleosomes and kinetochore attachment sites is unknown. Purification of native kinetochores from K. marxianus yielded a mixed population, with one subpopulation that appeared to consist of doublets, making it unclear whether K. marxianus shares the same attachment architecture as S. cerevisiae. Here, we demonstrate that though the doublet kinetochores have a functional impact on kinetochore strength, kinetochore localization throughout the cell cycle appears conserved between these two yeasts. In addition, whole spindle electron tomography demonstrates that a single microtubule binds to each chromosome. Single-molecule nucleosome mapping analysis suggests the presence of a single centromeric nucleosome. Taken together, we propose that the K. marxianus point centromere assembles a single centromeric nucleosome that mediates attachment to one microtubule.

cell biology↗

bioRxiv2025

Action mechanism of a novel agrichemical quinofumelin against Fusarium graminearum

Modern fungicides have made significant contributions to crop disease management, but the development of resistant fungal strains has caused their failure in disease control. Therefore, developing fungicides with novel action mechanisms is the most effective measure to manage resistance. Quinofumelin, a novel quinoline fungicide, exhibits exceptional antifungal activity against phytopathogens. However, there is currently no available information on its mechanism of action. Here, we used transcriptome and metabolome analysis to observe a co-enrichment pattern of differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) within pyrimidine biosynthesis pathway (PBP), identifying down-regulation of dihydroorotate dehydrogenase (DHODH). Exogenous uridine monophosphate (UMP), uridine or uracil (metabolites in PBP) successfully restored quinofumelin-induced inhibition of mycelial growth in Fusarium graminearum and Fusarium asiaticum. Additionally, the deletion of FgDHODHII was determined to be lethal; however, mycelial growth of {Delta}FgDHODHII mutants could be restored by adding UMP, uridine or uracil. These findings indicate that the deficiencies in FgDHODHII are functionally equivalent to complete inhibition of its activity by quinofumelin. Finally, molecular docking, surface plasmon resonance (SPR) and microscale thermophoresis (MST) results strongly support the precise interaction between quinofumelin and FgDHODHII. Collectively, these findings provide compelling evidence for the involvement of de novo uracil biosynthesis as mechanism of action for quinofumelin while identifying FgDHODHII as its specific target.

pathology↗

bioRxiv2025

Rational Design and Optimization of a Potent IDO1 Proteolysis Targeting Chimera (PROTAC)

Indoleamine 2,3-dioxygenase 1 (IDO1) is a potently immunosuppressive protein that inhibits antitumor immunity through both tryptophan metabolism and non-enzymatic functions. Pharmacological therapies targeting IDO1 enzyme activity have generally failed to improve the overall survival of patients with cancer. Developing new therapeutic agents that are capable of neutralizing both enzyme-and non-enzyme-derived immunosuppressive IDO1 effects is therefore of high interest. We previously described the development of a novel Proteolysis Targeting Chimera (PROTAC), NU223612, that degrades IDO1 in cultured human glioblastoma (GBM) cells, as well as in well-established brain tumors, in vivo. In this study, we rationally optimized the composition, rigidity, and linker orientation of the PROTAC structure to create NU227326, which degrades IDO1 with a DC50 of 5 nM in human GBM cells. Mechanistic studies showed that IDO1 degradation occurred through the ubiquitin-proteasome system and was sustained for at least 2 days, supporting NU227326 as a highly potent IDO1 PROTAC suitable for further studies in GBM and other human cancers.

biochemistry↗

bioRxiv2025

A kinetic model for USP14 regulated substrate degradation in 26S proteasome

Despite high-resolution structural studies on the USP14-proteasome-substrate complexes, time-resolved cryo-electron microscopy (cryo-EM) results on USP14-regulated allostery of the 26S proteasome are still very limited and a quantitative understanding of substrate degradation dynamics remains elusive. In this study, we propose a mean field model of ordinary differential equations (ODEs) for USP14 regulated substrate degradation in 26S proteasome. The kinetic model incorporates recent cryo-EM findings on the allostery of 26S proteasome and generates results in good agreement with time-resolved experimental observations. The model elucidates that USP14 typically reduces the substrate degradation rate and reveals the functional dependence of this rate on the concentrations of substrate and adenosine triphosphate (ATP). The half-maximal effective concentration (EC50) of the substrate for different ATP concentrations is predicted. When multiple substrates are present, the model suggests that substrates that are easier to insert into the OB-ring and disengage from the proteasome, or less likely to undergo deubiquitination would be more favored to be degraded by the USP14-bound proteasome. Author SummaryThe proteasome is a crucial protein complex involved in the degradation of damaged or unnecessary proteins within cells, requiring ATP and ubiquitin for its functioning. It is regulated by cellular factors that transiently associate with it, often referred to as proteasome-associated proteins. USP14 is such a protein that activates its deubiquitination activity through reversible binding to the proteasome, thereby decreasing the substrate degradation activity of the proteasome. In this study, we developed a kinetic model to describe how USP14 regulates substrate degradation in proteasome based on recent experimental findings. The model yields result consistent with experimental observations, demonstrating that the mean-field description of mass action law for chemical reactions also applies to complex biomolecular machineries.

biophysics↗

bioRxiv2024

Spatial-DC: a robust deep learning-based method for deconvolution of spatial proteomics

Spatial proteomics studies the spatial distribution of proteins within cells or tissues, providing a new perspective for comprehending cellular processes and disease mechanisms. One important challenge of current spatial proteomics technologies is low resolution, resulting in multiple cells in each spatial proteomics spot. While methods have been proposed to infer the composition of potential cell types in such spots for spatial transcriptomics, the depressed correlation and divergent quantification between transcriptome and proteome limits their capability in spatial proteomics. To enhance the utility of spatial proteomics data, we propose Spatial-DC (Spatial Digital Cytometry), a deep learning-based framework that infers cell-type composition in each spot and reconstructs spatially and cell-type resolved proteomic profiles. We achieve this by utilizing transfer learning and self-supervised learning with graph convolutional networks (GCN), which enables the incorporation of target spatial proteomics with reference single-cell or single-cell-type proteomics data. Through extensive simulations of spatial proteomics data, we demonstrate that Spatial-DC outperforms eight state-of-the-art methods in estimating cell-type composition and provides meaningful reconstructions of proteomic profiles for individual cell types. We apply Spatial-DC to different tissues measured using both multiplexed antibody-based and mass spectrometry (MS)-based spatial proteomics technologies. The results showcase Spatial-DCs superior sensitivity in providing more refined cell-type distribution maps compared to cell-type-specific marker-based distributions and its feasibility in reconstructing spatially and cell-type resolved proteomic profiles from real-world spatial proteomics data. Moreover, we validate Spatial-DC with a newly self-collected pancreatic cancer spatial proteomics data characterized by complex tumor microenvironment (TME) and identify the signaling direction and strength at both spatial and cell-type levels within the TME, suggesting cell-type-specific and spatially-resolved interactions linked to tumor outcomes. Our results highlight Spatial-DC as a versatile tool for the deconvolution of spatial proteomics data across various tissue slices, providing a reliable foundation for downstream analysis.

bioinformatics↗

bioRxiv2024

Incomplete lineage sorting of segmental duplications defines the human chromosome 2 fusion site early during African great ape speciation

All great apes differ karyotypically from humans due to the fusion of chromosomes 2a and 2b, resulting in human chromosome 2. Yet, the structure, function, and evolutionary history of the genomic regions associated with this fusion remain poorly understood. Here, we analyze finished telomere-to-telomere chromosomes in great apes and macaques to show that the fusion was associated with multiple pericentric inversions, segmental duplications (SDs), and the rapid turnover of subterminal repetitive DNA. We characterized the fusion site at single-base-pair resolution and identified three distinct SDs that originated more than 5 million years ago. These three distinct SDs were differentially distributed among African great apes as a result of incomplete lineage sorting (ILS) and lineage-specific duplication. Most conspicuously, one of these SDs shares homology to a hypomethylated SD spacer sequence present in hundreds of copies in the subterminal heterochromatin of chimpanzees and bonobos. The fusion in human was accompanied by a systematic degradation of the three divergent -satellite arrays representing the ancestral centromere creating five distinct structural haplotypes in humans. CRISPR/Cas9-mediated depletion of the fusion site in human cell lines significantly alters the expression of 108 genes, indicating a potential regulatory consequence to this human-specific karyotypic change.

evolutionary biology↗

bioRxiv2024

Salt-dependent non-catalytic allostery of human USP14-regulated 26S proteasome

USP14, a deubiquitylating enzyme, regulates 26S proteasome function both catalytically and non-catalytically through multiple checkpoints. How USP14 non-catalytically regulates the proteasome activity remains elusive. Here, we combined genetic engineering and cryo-EM to disentangle how USP14 non-catalytically regulates proteasome activity in a salt-dependent manner. By solving 16 high-resolution cryo-EM structures of substrate-engaged human 26S proteasome complexed with a catalytically deficient mutant USP14, we demonstrate that USP14s non-catalytic activity alone can induce parallel pathways of proteasome state transitions, leading to opposing substrate fates. The USP14 mutant allosterically reprograms the AAA-ATPase motor, inducing novel substrate-engaged conformations and filling major gaps in understanding asymmetric ATP-hydrolysis cycling around the ATPase ring. Time-resolved cryo-EM and functional analysis reveal that sodium or potassium promotes substrate-engaged pathways and suppresses USP14 activity for enhanced degradation, uncovering another layer of complexity in proteasome regulation.

biochemistry↗

bioRxiv2024

Deaminase-assisted single-molecule and single-cell chromatin fiber sequencing

Gene regulation is mediated by the co-occupancy of numerous proteins along individual chromatin fibers. However, our tools for deeply profiling how proteins co-occupy individual fibers, especially at the single-cell level, remain limited. We present Deaminase-Assisted single-molecule chromatin Fiber sequencing (DAF-seq), which leverages a non-specific double-stranded DNA deaminase toxin A (SsDddA) to efficiently stencil protein occupancy along DNA molecules via selective deamination of accessible cytidines, which are preserved via C-to-T transitions upon DNA amplification. We demonstrate that DAF-seq enables [~]200,000-fold enrichment of target loci for single-molecule footprinting at near single-nucleotide resolution, enabling the precise delineation of the regulatory logic guiding neighboring proteins to cooperatively occupy chromatin fibers. Furthermore, DAF-seq enables the synchronous identification of single-molecule chromatin and genetic architectures - resolving the functional impact of rare somatic variants, as well as transitional chromatin states guiding haplotype-selective promoter actuation. Finally, we demonstrate that single-cell DAF-seq enables the accurate reconstruction of the diploid genome and epigenome from a single cell, revealing that a cells accessible regulatory landscape can diverge by as much as 63% while still retaining the cells identity. Overall, DAF-seq enables the comprehensive characterization of protein occupancy and chromatin accessibility across entire chromosomes with single-nucleotide, single-molecule, single-haplotype, and single-cell precision.

genomics↗

bioRxiv2024

Abl kinases regulate FGF signaling independent of Crk phosphorylation to prevent Peters anomaly

Peters anomaly, the most common cause of congenital corneal opacity, stems from corneal-lenticular adhesion. Despite numerous identified mutations, a cohesive molecular framework of the diseases etiology remains elusive. Here, we identified Abl kinases as pivotal regulators of FGF signaling, as genetic ablation of Abl kinases restores lens induction even in the absence of FGF signaling. Intriguingly, both Abl kinase deficiency and increased FGF-Ras activity result in Peters anomaly independent of ERK signaling, which can be rescued by allelic deletion of Abl substrate, Crk. However, contrary to the prevailing belief that Abl kinases regulate Crk proteins by direct phosphorylation, mutations at Abl kinase phosphorylation sites on Crk and CrkL did not yield any observable effects. Instead, our findings reveal that Abl kinases phosphorylate Ptpn12, which in turn inhibits p130Cas phosphorylation and Crk recruitment, crucial for Rho GTPases activation and cytoskeletal dynamics. Consequently, Abl kinase deficiency reduces actomyosin contractility within the lens vesicle and genetically interacts with RhoA inhibition. Conversely, Rac1 deletion mitigates Peters anomaly in models with aberrant FGF, Abl kinase and RhoA signaling. Our results demonstrate that Abl kinases regulate FGF signaling to balance RhoA and Rac1 activity via the Ptpn12-p130Cas pathway, suggesting that targeting tension-mediated lens vesicle separation could be a therapeutic strategy for Peters anomaly.

developmental biology↗

bioRxiv2024

Shc1 cooperates with Frs2 and Shp2 to recruit Grb2 in FGF-induced lens development

Fibroblast growth factor (FGF) signaling elicits multiple downstream pathways, most notably the Ras/MAPK cascade facilitated by the adaptor protein Grb2. However, the mechanism by which Grb2 is recruited to the FGF signaling complex remains unresolved. Here we showed that genetic ablation of FGF signaling prevented lens induction by disrupting transcriptional regulation and actin cytoskeletal arrangements, which could be reproduced by deleting the juxtamembrane region of the FGF receptor and rescued by Kras activation. Conversely, mutations affecting the Frs2-binding site on the FGF receptor or the deletion of Frs2 and Shp2 primarily impact later stages of lens vesicle development involving lens fiber cell differentiation. Our study further revealed that the loss of Grb2 abolished MAPK signaling, resulting in a profound arrest of lens development. However, removing Grb2s putative Shp2 dephosphorylation site (Y209) neither produced a detectable phenotype nor impaired MAPK signaling during lens development. Furthermore, the catalytically inactive Shp2 mutation (C459S) only modestly impaired FGF signaling, whereas replacing Shp2s C-terminal phosphorylation sites (Y542/Y580) previously implicated in Grb2 binding only caused placental defects, perinatal lethality, and reduced lacrimal gland branching without impacting lens development, suggesting that Shp2 only partially mediates Grb2 recruitment. In contrast, we observed that FGF signaling is required for the phosphorylation of the Grb2-binding sites on Shc1 and the deletion of Shc1 exacerbates the lens vesicle defect caused by Frs2 and Shp2 deletion. These findings establish Shc1 as a critical collaborator with Frs2 and Shp2 in targeting Grb2 during FGF signaling.

developmental biology↗

bioRxiv2024

Integrated temporal profiling of iPSCs-derived motor neurons from ALS patients carrying C9orf72, FUS, TARDBP, and SOD1 mutations

Amyotrophic Lateral Sclerosis (ALS) is a lethal neurodegenerative disease that damages motor neurons in the central nervous system, causing progressive muscle weakness that ultimately leads to death. However, its underlying mechanisms still need to be fully understood, particularly the heterogeneity and similarity between various gene mutants during disease progression. In this study, we conducted temporal RNA-seq profiling in human induced pluripotent stem cells (hiPSCs) and iPSC-derived motor neurons (iMNs) carrying the C9orf72, FUS, TARDBP, and SOD1 mutations from both ALS patients and healthy individuals. We discovered dysregulated gene expression and alternative splicing (AS) throughout iMN development and maturation, and ALS iMNs display enrichment of cytoskeletal defects and synaptic alterations from premature stage to mature iMNs. Our findings indicate that synaptic gene dysfunction is the common molecular hallmark of fALS, which might result in neuronal susceptibility and progressive motor neuron degeneration. Analysis of upstream splicing factors revealed that differentially expressed RNA-binding proteins (RBPs) in ALS iMNs may cause abnormal AS events, suggesting the importance of studying RBP defects in ALS research. Overall, our research provides a comprehensive and valuable resource for gaining insights into the shared mechanisms of ALS pathogenesis during motor neuron development and maturation in iMN models.

neuroscience↗

bioRxiv2024

Non-equilibrium remodelling of collagen-IV networks in silico

Collagen IV is one of the main components of the basement membrane, a layer of material that lines the majority of tissues in multicellular organisms. Collagen-IV molecules assemble into networks, providing stiffness and elasticity to tissues and informing cell and organ shape, especially during development. In this work, we develop two coarse grained models for collagen-IV molecules that retain biochemical bond specificity and coarse-grain at different length scales. Through molecular dynamics simulations, we test the assembly and mechanics of the resulting networks and measure their response to strain in terms of stress, microscopic alignment, and bond dynamics. Within the basement membrane, collagen-IV networks rearrange by molecule turnover, which affects tissue organisation and can be linked with enzyme activity. Here we explore network rearrangements via bond remodelling -- the process of dynamical breaking and remaking of bonds between network molecules. We then investigate the effects of active (enzymatic) bond remodelling. We find that this non-equilibrium remodelling allows a network to keep its integrity under strain, while relaxing fully over a variety of timescales - a dynamic response that is unavailable to networks undergoing equilibrium remodelling.

biophysics↗