Biology subjects

Dutta, S.

Publications and source records attributed to Dutta, S..

At least 73 records · Page 4Linked to original sources

bioRxiv2025

Persistent dopamine-dependent remodeling of the neural transcriptome in response to pregnancy and postpartum

Pregnancy and postpartum experiences represent transformative physiological states that impose lasting demands on the maternal body and brain, resulting in lifelong neural adaptations1-6. However, the precise molecular mechanisms driving these persistent alterations remain poorly understood. Here, we used brain-wide transcriptomic profiling to define the molecular landscape of parity-induced neural plasticity, identifying the dorsal hippocampal formation (dHF) as a key site of transcriptional remodeling. Combining single-cell RNA sequencing with a maternal-pup separation paradigm, we additionally demonstrated that chronic postpartum stress significantly disrupts dHF adaptations by altering dopamine dynamics, leading to changes in the dopamine-dependent histone post-translational modification - H3 dopaminylation, with further alterations in transcription, cellular plasticity, and behavior. In human dorsal subiculum, a brain structure within the dHF, we uncovered conserved patterns of parity-dependent alterations in H3 dopaminylation and transcription. We further established the sufficiency of dopamine modulation in regulating these parity-induced adaptations via chemogenetic suppression of dopamine release into the dHF, which recapitulated key epigenomic and behavioral features of parity in virgin female mice. In sum, our findings establish dopamine as a central regulator of parity-induced neuroadaptations in humans and mice, revealing a fundamental transcriptional mechanism by which female reproductive experiences remodel the brain to sustain long-term behavioral adaptations.

neuroscience↗

bioRxiv2025

Molecularly-guided spatial proteomics captures single-cell identity and heterogeneity of the nervous system

Single-cell spatial proteomics (scSP) holds substantial potential for profiling healthy and diseased tissues. The emerging method of molecularly-guided unbiased scSP has mostly been applied to peripheral somatic tissues. Here, we optimize and apply scSP to the healthy and diseased mammalian brain, using molecularly-guided laser capture microdissection and unbiased mass spectrometry. We systematically evaluate the effects of tissue fixation, marker staining, and sample input size on proteome coverage and quantitative accuracy. We benchmark this workflow by profiling region-specific neuronal proteomes and describing the response of non-neuronal cells to acute brain injury. Across these applications, we integrate complementary transcriptomic resources to evaluate cross-modality trends and refine neuronal proteomic results by filtering out protein signals likely arising from non-neuronal cells, an essential consideration in heterogeneous tissues such as the brain. Finally, we leverage this approach to resolve proteomic differences between dopaminergic neuron subpopulations with differential vulnerability to Parkinsons disease and to uncover disease-specific disruptions in -synuclein-aggregate-bearing single dopaminergic neurons. Together, these data demonstrate the utility of scSP in neuroscience research for understanding fundamental biology and the molecular drivers of neurological conditions.

neuroscience↗

bioRxiv2025

Distinct filament morphology and membrane tethering features of the dual FtsZs in Odinarchaeota

The deep-branching Asgard archaea have emerged as a model to study Eukaryogenesis as they harbor homologs of many of the major eukaryotic protein families. In this study, we use Candidatus Odinarchaeota FtsZs as representatives to understand the probable origin, evolution, and assembly of the FtsZ-Tubulin protein superfamily in Asgard archaea. We have performed a comparative analysis of the biochemical properties and cytoskeletal assembly of FtsZ1 and FtsZ2, the two FtsZ isoforms in the Odinarchaeota metagenome. Our electron microscopy analysis reveals that OdinFtsZ1 assembles into curved single protofilaments, while OdinFtsZ2 forms stacked spiral ring-like structures. Upon sequence analysis, we identified an N-terminal amphipathic helix in OdinFtsZ1, which mediates direct membrane tethering. In contrast, OdinFtsZ2 is recruited to the membrane by the membrane-anchor OdinSepF via OdinFtsZ2s C-terminal tail. Overall, we report the presence of two distant evolutionary paralogs of FtsZ in Odinarchaeota, with distinct filament assemblies and differing modes of membrane targeting mechanisms, namely direct vs SepF-mediated membrane binding. Our findings highlight the diversity of FtsZ proteins in the transitional archaeal phylum Odinarchaeota, providing valuable insights into the evolution and differentiation of tubulin family proteins.

biochemistry↗

bioRxiv2025

Synaptic phosphoproteome modifications and cortical circuit dysfunction are linked to the early-stage progression of alpha-synuclein aggregation

Cortical dysfunction is increasingly recognized as a major contributor to the non-motor symptoms associated with Parkinsons disease (PD) and other synucleinopathies. Although functional alterations in cortical circuits have been observed in preclinical PD models, the underlying molecular mechanisms are unclear. To bridge this knowledge gap, we investigated tissue-level changes in the cortex of rats and mice treated with alpha-synuclein (aSyn) seeds using a multi-omics approach. Our study revealed significant phosphoproteomic changes, but not global proteomic or lipid profiling changes, in the rat sensorimotor cortex 3 months after intra-striatal injection with aSyn preformed fibrils (PFFs). Gene ontology analysis of the phosphoproteomic data revealed that PFF administration impacted pathways related to synaptic transmission and cytoskeletal organization. Similar phosphoproteomic perturbations were observed in the sensorimotor cortex of mice injected intrastriatally or intracortically with aSyn PFFs. Functional analyses demonstrated increased neuronal firing rates and enhanced spike-spike coherence in the sensorimotor cortex of PFF-treated mice, suggesting that aSyn seeds induced cortical circuit dysfunction. Bioinformatics analysis of the altered phosphosites indicated the involvement of several kinases, including casein kinase-2 (CK2) and Protein Kinase A (PKA). Enrichment of kinase-activating pT/pY MAPK (ERK) phosphosites revealed apparent engagement of the ERK signaling cascade and led to the identification of pERK1/2-positive intraneuronal granulovacuolar body (GVB)-like structures specifically in aggregate-bearing neurons. Collectively, these findings highlight the importance of phosphorylation-mediated signaling pathways in the cortical response to aSyn pathology spread in PD and related synucleinopathies, setting the stage for developing new therapeutic strategies.

neuroscience↗

bioRxiv2025

Clonality, specificity, and HLA restriction of human T cell receptors against Plasmodium falciparum CSP

Plasmodium falciparum malaria remains a significant global health challenge. Current vaccines elicit antibody responses against circumsporozoite protein (PfCSP) that prevent the infection of hepatocytes but offer only moderate protection. Cellular immunity has emerged as a critical component of pre-erythrocytic protection that might be leveraged to develop improved PfCSP vaccines. Here, we characterized the clonality, molecular features, epitope specificity, and HLA-restrictions of the human PfCSP-specific CD4+ and CD8+ T cell response to vaccination with an adjuvanted PfCSP vaccine, FMP013/ALFQ. Using TCR expression cloning, we identified novel conserved CD4+ T cell epitopes in the PfCSP N terminus and show that the C-terminal CS.T3 epitope was targeted by CD4+ and rare CD8+ T cells, which recognized this epitope co-receptor-independently presented on a class II HLA. Our findings provide insights into the utility of these epitopes as targets for strain-transcending immunity compared to the immunodominant but highly polymorphic epitopes in the PfCSP C terminus, offering guidance for the design of improved malaria vaccines.

immunology↗

bioRxiv2024

Resolving the design principles that control postnatal vascular growth and scaling

After birth, tissues grow continuously until reaching adult size, with each organ exhibiting unique cellular dynamics, growth patterns, and (stem or non-stem) cell sources. Using a suite of experimental and computational multiscale approaches, we found that aortic expansion is guided by specific biological principles and scales with the vertebral column rather than animal body weight. Expansion proceeds via two distinct waves of arterial cell proliferation along blood flow that are spatially stochastic, yet temporally coordinated. Each wave exhibits unique cell cycle kinetics and properties, with the first wave exhibiting cell cycle durations as fast as 6 hours. Single-cell RNA sequencing showed changes in fatty acid metabolism concomitant with an increase in cell size. Mathematical modeling and experiments indicated endothelial cell extrusion is essential for homeostatic aortic growth and balancing excess proliferation. In a genetic model of achondroplasia, the aorta achieves proper scaling through enhanced cell extrusion while maintaining normal proliferation dynamics. Collectively, these results provide a blueprint of the principles that orchestrate aortic growth which depends entirely on differentiated cell proliferation rather than resident stem cells.

developmental biology↗

bioRxiv2024

Perilipin 5 Phosphorylation is Dispensable for Upregulation of Hepatic Lipid Metabolism Genes upon Fasting but Required for Insulin Receptor Substrate 2 Expression in Male Mice

ObjectivePerilipin 5 (PLIN5) is a lipid droplet protein highly expressed in cells that actively oxidize fatty acids. Previous in vitro studies have revealed that PLIN5 phosphorylation (p-PLIN5) at serine 155 by PKA is critical for transcriptional regulation of PPARa target genes by which PLIN5 adapt cells for fatty acid oxidation. We aim to determine the extent of p-PLIN5 in vivo and the consequence of impaired PLIN5 phosphorylation in the liver by using a whole-body knock-in of phosphorylation resistant PLIN5 (SA/SA) in mice. MethodsWe measured PLIN5 and p-PLIN5 with mass spectrometry and Phos-tag gels. We assessed serum chemistry in WT and SA/SA mice upon fasting. RNA sequencing and qPCR compared the gene expression in the liver of SA/SA and WT mice after overnight fast. ResultsPlin5 phosphorylation at S155 was increased in the liver LD fraction of fasted mice compared with that of fed mice by mass spectrometry (p<0.05). qPCR of key lipid metabolism genes did not differ between WT and SA/SA liver upon fasting. Male SA/SA mice had a higher fasting blood glucose (p<0.05) without a difference in body weight, serum insulin, or serum lipids. IRS2 was reduced in the liver of fasted male SA/SA mice (p<0.05). ConclusionPLIN5 S155 phosphorylation is dispensable for the upregulation of lipid metabolism genes important for fasting response in vivo. Impaired phosphorylation also had little effect on serum lipids or liver TG. However, SA/SA mice showed decreased IRS2 expression in the liver, which may contribute to glucose intolerance in SA/SA male mice.

molecular biology↗

bioRxiv2024

Dynamic Mechanism for Subtype Selectivity of Endocannabinoids

Endocannabinoids are naturally occurring lipid-like molecules that bind to cannabinoid receptors (CB1 and CB2) and regulate many of human bodily functions via the endocannabinoid system. There is a tremendous interest in developing selective drugs that target the CB receptors. However, the biophysical mechanisms responsible for the subtype selectivity for endocannbinoids have not been established. Recent experimental structures of CB receptors show that endocannbinoids potentially bind via membrane using the lipid access channel in the transmembrane region of the receptors. Furthermore, the N-terminus of the receptor could move in and out of the binding pocket thereby modulating both the pocket volume and its residue composition. On the basis of these observations, we propose two hypothesis to explain the selectivity of the endocannabinoid, anandamide for CB1 receptor. First, the selectivity arises from distinct enthalpic ligand-protein interactions along the ligand binding pathway formed due to the movement of N-terminus and subsequent shifts in the binding pocket composition. Second, selectivity arises from the volumetric differences in the binding pocket allowing for differences in ligand conformational entropy. To quantitatively test these hypothesis, we perform extensive molecular dynamics simulations ([~]0.9 milliseconds) along with Markov state modeling and deep learning-based VAMPnets to provide an interpretable characterization of the anandamide binding process to cannabinoid receptors and explain its selectivity for CB1. Our findings reveal that the distinct N-terminus positions along lipid access channels between TM1 and TM7 lead to different binding mechanisms and interactions between anandamide and the binding pocket residues. To validate the critical stabilizing interactions along the binding pathway, relative free energy calculations of anandamide analogs are used. Moreover, the larger CB2 pocket volume increases the entropic effects of ligand binding by allowing higher ligand fluctuations but reduced stable interactions. Therefore, the opposing enthalpy and entropy effects between the receptors shape the endocannabinoid selectivity. Overall, the CB1 selectivity of anandamide is explained by the dominant enthalpy contributions due to ligand-protein interactions in stable binding poses. This study shed lights on potential selectivity mechanisms for endocannabinoids that would aid in the discovery of CB selective drugs.

biophysics↗

bioRxiv2024

Cardiomyopathic mutations of lamin A perturb mutual interactions of lamin, nuclear membrane, and chromatin leading to LLPS

Lamins are nuclear intermediate filaments constituting the nuclear lamina which maintains the structural integrity of the nucleus and play a key role in the spatial organisation of the genome. Mutations in the lamin protein have been associated with diverse diseases collectively known as laminopathies. In this study, we focused on two lamin A mutants - E161K and K97E - associated with dilated cardiomyopathy (DCM). Through confocal imaging, we established that these mutations cause large scale disruption of the peripheral lamin and consequent heterochromatin organisation, along with the formation of lamin aggregates inside the nucleoplasm. Using coarse-grained polymer simulations, we uncovered the role of lamin-lamin, lamin-membrane and lamin-chromatin interactions in maintaining wild-type lamin and chromatin organisation and showed that disruptions in these interactions can reproduce the experimental observations in the lamin mutants. These predictions were verified using 3D-FISH experiments to quantify the reorganisation of chromosome territories in these mutants. Using advanced imaging methods, we characterised the dynamical properties of the lamin aggregates in the mutants to show for the first time a liquid-like state of the lamin aggregates through a liquid-liquid phase separation. The altered lamin and chromatin interactions in the mutants thus manifest as liquid-like aggregates in the nucleoplasm leading to disruption of the spatial organisation of the genome in these laminopathy-associated mutants.

biophysics↗

bioRxiv2024

State of India's Birds 2023: A framework to leverage semi-structured citizen science for bird conservation

Birds and their habitats are threatened with extinction around the world. Regional assessments of the State of Birds are a vital means to prioritize data-driven conservation action by informing national and global policy. Such evaluations have traditionally relied on data derived from extensive, long-term, systematic surveys that require significant resources, limiting their feasibility to a few regions in the world. In the absence of such structured long-term datasets, semi-structured datasets have recently emerged as a promising alternative in other regions around the world. Semi-structured data are generated and uploaded by birdwatchers to citizen science platforms like eBird. Such data contain inherent biases because birdwatchers are not required to adhere to a fixed protocol. An evaluation of the status of birds from semi-structured data is therefore a difficult task that requires careful curation of data and the use of robust statistical methods to reduce errors and biases. In this paper, we present a methodology that was developed for this purpose, and was applied to produce the comprehensive State of Indias Birds (SoIB) 2023 report. SoIB 2023 assessed the status of 942 bird species in India by evaluating each species based on three metrics: 1) long-term change: change in abundance between the year 2022 and the year-interval pre-2000; 2) current annual trend: mean annual change in abundance from 2015 to 2022; and 3) distribution range size. We found evidence that 204 species have declined in the long term, and 142 species are currently declining. We present and discuss important insights about Indias birds that can guide research and conservation action in the region. We hope that the detailed methodology described here can act as a blueprint to produce State of Birds assessments from semi-structured citizen science datasets and springboard conservation action in many other regions where structured data is lacking but strong communities of birders exist. Open Research StatementThe primary data are already publicly available on eBird (Sullivan et al. 2014), and other data are already published in a GitHub repository (stateofindiasbirds 2024).

ecology↗

bioRxiv2024

Male and female mice respectively form stronger social aversive memories with same and different sex conspecifics

Mice offer a wealth of opportunities for investigating brain circuits regulating multiple behaviors, largely due to their genetic tractability. Social behaviors are translationally relevant, considering both mice and humans are highly social mammals, and human social behavior disruptions are key symptoms of myriad neuropsychiatric disorders. Stresses related to social experiences are particularly influential in the severity and maintenance of neuropsychiatric disorders like anxiety disorders, and trauma and stressor-related disorders. Yet, induction and study of social stress in mice has disproportionately focused on males, influenced heavily by their inherent territorial nature. Social target-instigated stress (i.e., defeat), while ethologically relevant, is quite variable and predominantly specific to males, making rigorous and sex-inclusive studies challenging. In pursuit of a controllable, consistent, high throughput, and sex-inclusive method for social stress elicitation, we modified a paradigm to train male and female F1 129S1/SvlmJ x C57BL/6J mice to associate (via classical conditioning) same or different sex C57BL/6J targets with a mild, aversive stimulus. While further paradigm optimization is required, social interaction testing 24 h after conditioning indicates males socially conditioned better to male targets by exhibiting reduced social interaction, whereas females appeared not to form social stimulus associations. Serum corticosterone levels inversely corresponded to social avoidance after different sex, but not same sex, conditioning, suggesting corticosterone-mediated arousal influences cross-sex interactions. These rigorously controlled null outcomes align with past pursuits limited success in creating a sex-inclusive social stress paradigm. Significance StatementValidated paradigms to study social stress in female mice, and across sexes, are needed. We modified a published male mouse protocol by using classical conditioning to pair an aversive stressor with a target. Our goal was to create a uniform, cross-sex, high-throughput social stress technique to advance future research. Though our modified paradigm requires future improvements, we did acquire evidence that males can be socially conditioned in this way, and female same sex social engagement can be attenuated by a preceding non-social aversive experience. These null findings, while not achieving our goal, provide useful information to advance future sex-inclusive social stress investigations.

neuroscience↗

bioRxiv2024

Faster amylin aggregation on fibrillar collagen hastens diabetic progression through β cell death and loss of function

Amyloid deposition of the neuroendocrine peptide amylin in islet tissues is a hallmark of type 2 diabetes (T2DM), leading to {beta}-cell toxicity through nutrient deprivation, membrane rupture and apoptosis. Though accumulation of toxic amylin aggregates in islet matrices is well documented, the role of the islet extracellular matrix in mediating amylin aggregation and its pathological consequences remains elusive. Here, we address this question by probing amylin interaction with collagen I (Col I)--whose expression in the islet tissue increases during diabetes progression. By combining multiple biophysical techniques, we show that hydrophobic, hydrophilic & cation-{pi} interactions regulate amylin binding to Col I, with fibrillar collagen driving faster amylin aggregation. Amylin-entangled Col I matrices containing high amounts of amylin induce death and loss of function of INS1E {beta}-cells. Together, our results illustrate how amylin incorporation in islet matrices through amylin-Col interactions drives T2DM progression by impacting {beta}-cell viability and insulin secretion.

biophysics↗

bioRxiv2024

Pigment-dispersing factor neuropeptides act as multifunctional hormones and modulators in tardigrades

Pigment-dispersing factors (PDFs) are neuropeptides that play key roles in controlling the circadian rhythms in various insects, whereas their function remains elusive in other protostomes including tardigrades (water bears). Here we show that the three PDFs of the tardigrade Hypsibius exemplaris are co-localized in two pairs of inner lobe cells in the brain, whereas only one PDF occurs in four additional cerebral and two extracerebral cells. The axons of the inner lobe cells pass through the contralateral brain hemisphere, descend to the ventral nerve cord and terminate in two pairs of potential release sites in the posteriormost trunk ganglion. Using in vitro assays, we demonstrate that all three PDFs and their deorphanized receptor (PDFR) are functional. Widespread localization of PDFR suggests that tardigrade PDFs may act as multifunctional hormones and neuromodulators that control major functions including light detection, neural processing, locomotion, feeding, digestion, osmoregulation, growth, embryonic development, and oogenesis/reproduction.

zoology↗

bioRxiv2024

CD44/Integrin β1 association drives fast motility on HA substrates

In addition to proteins such as collagen (Col) and fibronectin, the extracellular matrix (ECM) is enriched with bulky proteoglycan molecules such as hyaluronic acid (HA). However, how ECM proteins and proteoglycans collectively regulate cellular processes has not been adequately explored. Here, we address this question by studying cytoskeletal and focal adhesion organization and dynamics on cells cultured on polyacrylamide hydrogels functionalized with Col, HA and a combination of Col and HA (Col/HA). We show that fastest migration on HA substrates is attributed to the presence of smaller and weaker focal adhesions. Integrin {beta}1 co-localization and its association with CD44--which is the receptor for HA, and insensitivity of cell spreading to RGD on HA substrates suggests that focal adhesions on HA substrates are formed via integrin association with HA bound CD44. Consistent with this, adhesion formation and cell motility were inhibited when CD44 was knocked out. Collectively, our results suggest that association of integrin {beta}1 with CD44 drives fast motility on HA substrates.

cell biology↗

bioRxiv2024

Crosstalk between plasma membrane and Staphylococcus α-hemolysin during oligomerization

The infectious microbe Staphylococcus aureus releases an array of cytotoxic pore-forming toxins (PFTs) that severely damage the cell membrane during bacterial infection. However, the interaction interfaces between the host cell and toxin were merely explored. Herein, we monitored the active oligomeric states facilitated membrane disruption processes such as lysis, and protrusion in the plasma membrane and lipid membrane. Furthermore, necrosis was triggered in the neutrophil-like cells upon synergistic binding and oligomerization of the monomeric -HL. Additionally, we solved RBC membrane stabilized structure of different conformational states of this {beta}-PFT using a single-particle cryo-EM. We further confirmed that internal membrane fluidity was the deterministic factor associated with the formation of intermediate pre-pores, heptameric pore-like, and complete pore species. Together, this is the first study to unveil the structure-function analysis of pre-pore to pore transition of any small {beta}-PFT during its crosstalk with the cell. HighlightsO_LI-HL promotes necrosis in HL60 cells and lysis of shorter lipid bilayer region. C_LIO_LICryo-EM of small PFT in the cellular environment. C_LIO_LIStructural characterization of heptameric pore, pore-like, and pre-pore complex in the presence of RBCs. C_LIO_LIBilayer phase behavior (Ld/Lo) governs different conformational and geometrical variants of -HL. C_LI

biophysics↗

bioRxiv2024

Co-existence of plasmid-mediated blaNDM-1 and blaNDM-5 in Escherichia coli sequence type 167 and ST101 and their discrimination through restriction digestion

The concurrent presence of multiple New Delhi metallo-{beta}-lactamase (blaNDM) variants within an isolate often goes undetected without the use of next-generation sequencing. This study detects and characterizes dual blaNDM-variants in Escherichia coli through Sanger and whole-genome sequencing. Additionally, a rapid identification method utilizing restriction digestion was designed for detecting variants carrying M154L mutation. Antibiotic susceptibility, minimal inhibitory concentration for meropenem and ertapenem, PCR and Sanger sequencing of blaNDM along with genome sequencing using Ilumina and Nanopore technology were conducted. Transmissibility and replicon types of blaNDM-harbouring plasmids were evaluated. Restriction digestion using restriction enzyme, BtsCI was developed to distinguish between blaNDM-1 and variants possessing M154L mutations. Two isolates belonging to phylogroups A; ST167 and B1; ST101 and resistant to meropenem and ertapenem ([≥]16mg/L) were recovered from the blood of a neonate and the rectal swab of a pregnant woman respectively. blaNDM was detected by PCR, and Sanger sequences of blaNDM showed two peaks at 262 (G & T) and 460 (A & C) nucleotide positions indicative of more than one blaNDM variant. Hybrid assembly confirmed co-existence of blaNDM-1 and blaNDM-5 in each isolate. blaNDM-1 was located on IncY (ST167) and IncHI1A/HI1B (ST101), while blaNDM-5 was on a IncFIA/FII (ST167) and IncC (ST101) plasmids. Digestion with BtsC1 could discriminate blaNDM-1 and blaNDM-5. Co-existence of multiple blaNDMS, blaNDM-1 and blaNDM-5 in epidemic clones of E. coli is concerning. Restriction digestion method and Sanger sequencing can facilitate quick identification of dual blaNDM variants in single isolate. ImportanceThe global dissemination of antimicrobial resistance genes is a serious concern. One such gene, blaNDM, has spread all across the globe via plasmids. blaNDM confers resistance against all {beta}-lactam antibiotics except monobactams. Most of the earlier literature reported presence of single blaNDM variants. However, this study reports the prevalence of dual blaNDM variants (blaNDM-1 and blaNDM-5) located on two separate plasmids identified in two distinct E. coli epidemic clones ST167 and ST101; isolated from a septicaemic neonate and a pregnant mother respectively. blaNDM-5 differs from blaNDM-1 due to presence of two point mutations i.e., V88L and M154L. This study detected dual blaNDM-variants through Sanger sequences and further validated through hybrid-genome assembly. Detection of multiple blaNDM-variants in a single isolate remains difficult until genome sequencing or southern blotting are carried out. Hence, a simple restriction digestion method was devised for rapid screening of dual blaNDM-variants containing M154L mutation.

microbiology↗

bioRxiv2024

Interplay of geometry and mechanics in epithelial wound healing

Wound healing is a complex biological process critical for maintaining an organisms structural integrity and tissue repair following an infection or injury. Recent studies have unveiled the mechanisms involving the coordination of biochemical and mechanical responses in the tissue in wound healing. In this article, we focus on the healing property of an epithelial tissue as a material while the effects of biological mechanisms such as cell crawling and tissue proliferation is minimal. We present a mathematical framework that predicts the fate of a wounded tissue based on the wounds geometrical features and the tissues mechanical properties. Precisely, adapting the vertex model of tissue mechanics, we predict whether a wound of a specific size in an epithelial monolayer characterized by certain levels of acto-myosin contractility and cell-cell adhesion will heal (i.e., close), shrink in size, or rupture the tissue further. Moreover, we show how tissue-mediated mechanisms such as purse-string tension at the wound boundary facilitate wound healing. Finally, we validate the predictions of our model by designing an experimental setup that enables us to create wounds of specific sizes in MDCK monolayers. Altogether, this work sets up a basis for interpreting the interplay of mechanical and geometrical features of a tissue in the process of wound healing.

biophysics↗

bioRxiv2024

Two distinct integrin binding sites on MMP9 drive cancer invasion by mediating integrin membrane trafficking & stabilization

Matrix stiffening has been established to drive cancer progression through increased activity of matrix metalloproteases (MMPs) which degrade the matrix creating paths for migration. However, the non-proteolytic functions of MMPs in cancer invasion remain relatively less understood. Here we have probed the importance of proteolytic and non-proteolytic functions of MMP9, which exhibits robust stiffness dependent expression and secretion in highly invasive cancer cells. We show that while MMP9 sustains spreading and 2D migration non-proteolytically by stabilizing focal adhesions, MMP9 proteolytic activity is essential for 3D invasion. We then establish the function of two distinct integrin {beta}1 (ITG {beta}1) binding sites on MMP9, with the hemopexin domain mediating co-packaging and co-transport of ITG {beta}1/MMP9 to the cell periphery, and the RGD domain stabilizing ITG {beta}1 on the cell membrane prior to matrix degradation. Together, our results illustrate how MMP9 optimizes cancer invasion by spatiotemporally integrating matrix remodeling with adhesion formation.

cell biology↗