Biology subjects

Zhang, S.

Publications and source records attributed to Zhang, S..

At least 253 records · Page 14Linked to original sources

bioRxiv2025

Cell size modulates ferroptosis susceptibility

Size is a fundamental property of cells that influences many aspects of their physiology. This is because cell size sets the scale for all subcellular components and drives changes in the composition of the proteome. Given that large and small cells differ in their biochemical composition, we hypothesize that they should also differ in how they respond to signals and make decisions. Here, we investigated how cell size affects susceptibility to cell death. We found that large cells are more resistant to ferroptosis caused by system xc- inhibition. Ferroptosis is a type of cell death characterized by the iron-dependent accumulation of toxic lipid peroxides. This process is opposed by cysteine-dependent lipid peroxide detoxification mechanisms. We found that larger cells exhibit higher concentrations of the cysteine-containing metabolite glutathione and lower concentrations of membrane lipid peroxides. Mechanistically, this can be explained by the fact that larger cells had lower concentrations of an enzyme that enriches cellular membranes with peroxidation-prone polyunsaturated fatty acids, ACSL4, and increased concentrations of the iron-chelating protein ferritin, the glutathione-producing enzymes glutamate-cysteine ligase and glutathione synthetase, and the lysosomal protease cathepsin B, which can catabolize cysteine-rich extracellular proteins to produce additional cystine for fueling the synthesis of glutathione. Taken together, our results highlight the significant impact of cell size on cellular function and survival, revealing a size-dependent vulnerability to ferroptosis that could influence therapeutic strategies based on this cell death pathway.

cell biology↗

bioRxiv2025

ATG gene duplication in vertebrates: evolutionary divergence and its functional implications

Macroautophagy (hereafter referred to as autophagy) requires the coordinated action of approximately 20 autophagy-related (ATG) genes. Duplication of ATG genes has had a major impact on the evolution of the autophagy pathway among major lineages. One duplication hotspot is in vertebrates. However, the exact duplication timing, post-duplication evolutionary divergence patterns, and its relation to functional differences among paralogs have not been investigated in detail. Here, we demonstrate that most ATG genes were likely duplicated by whole-genome duplication events near the root of vertebrates. We compared the sequence and gene expression divergence between paralogs and categorized the evolutionary fates (i.e., how ancestral function is divided between paralogs). Within the paralog pairs that evolved most asymmetrically, namely BECN, WIPI (WIPI1 and WIPI2), and ATG16, one paralog likely retained the ancestral function, allowing the other to evolve under less constraint. While no obvious asymmetry was observed between ATG9A and ATG9B in non-mammalian vertebrates, ATG9B experienced marked sequence divergence and expression level reduction in mammals, suggesting a shift in balance. Expression patterns among the ULK-1 (ULK1 and ULK2), GABARAP (GABARAP and GABARAPL1), and LC3 (LC3A and LC3B) pairs were more consistent with hypofunctionalization/dosage sharing, such that ancestral function depends on both paralogs. We also demonstrate that both ULK1 and ULK2 can support autophagy, whereas only BECN1, but not BECN2, has autophagic function and discuss the relationship between autophagic function and evolutionary divergence between paralogs. The present detailed analysis of ATG gene duplication in vertebrates provides a critical time-line for interpreting functional differentiation between homologs.

evolutionary biology↗

bioRxiv2025

Pan-cancer analysis reveals that tumor microbiomes generate specific epitopes through transcriptional reprogramming

The therapeutic promise of tumor microbial peptides faces a critical safety paradox: tumors and peritumor tissues harbor compositionally similar microbiomes, yet safe immunotherapy demands tumor-specific targeting. We performed comprehensive transcriptomic analysis of microbial communities from 1,868 tumor and peritumor samples across 11 cancer types. Although 88.5% of microbial species are present in both tissue types, tumor and peritumor tissues exhibit profound transcriptional divergence: only 34.1% of microbial genes are expressed in both tissue types, and merely 18.2% of predicted HLA-binding peptides overlap. This transcriptional divergence represents microbial transcriptional reprogramming (MTR) in tumor tissues, through which microbes activate distinct genomic regions while adapting to tumor microenvironmental pressures, thereby generating tumor-specific peptide repertoires. Using Microbial Transcriptional Reprogramming Index (MiTRI) to quantify MTR, we found that higher MiTRI values correlate with expanded immunogenic peptide repertoires. Mass spectrometry-based immunopeptidomics confirmed that 25% of naturally presented microbial peptides originate from MTR regions. Crucially, in microsatellite-stable colorectal cancer, neo-adjuvant therapy responders exhibited significantly higher MiTRI values. T cell receptors (TCRs) recognized MTR-derived epitopes at 2.10-fold higher rates than genome-wide epitopes, accounting for 79.1% of clonally expanded TCRs. These findings establish MTR as the principle that ensures the tumor-specificity and safety of micorbiome-directed immunotherapy.

cancer biology↗

bioRxiv2025

Neutrophil extracellular traps-mediated thrombosis drive pyrrolizidine alkaloid-induced hepatic sinusoidal obstruction syndrome

Hepatic sinusoidal obstruction syndrome (HSOS) caused by pyrrolizidine alkaloid (PA) is a life-threatening disease with limited treatments, yet the initiating vascular event remains undefined. Neutrophil extracellular traps (NETs), as key driver of immunothrombosis in various thromboinflammatory diseases, may represent a critical yet uncharacterized component in the pathogenesis of PA-HSOS. Rats and mice were separately administered monocrotaline (MCT) or senecionine (SEN) via gavage to induce HSOS. Human hepatic sinusoidal endothelial cell (HHSEC) and primary human neutrophil treated with MCT, SEN, or corresponding metabolites were used as in vitro models. In separate experiments, animals received a neutrophil elastase (NE) inhibitor or neutrophil-depleting antibody to evaluate the contribution of NETs. We detected NETs within the sinusoids of necrotic liver lobes, as evidenced by robust immunostaining for NETs markers, accompanied with elevated level of circulating cell-free DNA, and hepatic citrullinated histone H3. Sinusoidal microthrombi containing VWF, CD41, and fibrin(ogen) were also stained positive for neutrophils in PA-HSOS models. Treatment with NE inhibitor or neutrophil depletion markedly attenuated PA-induced liver injury by concomitantly suppressing NETs formation and intrahepatic thrombogenesis. In vitro, conditioned medium from HHSEC exposed to MCT or SEN metabolites potently induced NETs formation. HHSEC injured by PA metabolites released CXCL8. Furthermore, hepatic mRNA and protein levels of CXCL1 and CXCL2 (murine homologous to human CXCL8) were up-regulated in PA-HSOS models, accompanied by a parallel elevation of their high-affinity receptors, CXCR1 and CXCR2. Our study identifies NETs-mediated immunothrombosis as a key driver in HSOS, which provides a promising target for PA-HSOS treatment.

pharmacology and toxicology↗

bioRxiv2025

Sulcal landmarks reveal lineage-specific trajectories and multi-scale specialization of the mammalian cortex

An important topic of evolutionary neuroscience is to understand how brain function and structure across evolutionary time. In the absence of functional data for ancestral species, studies often rely on structural features such as cortical volume or surface area. However, atlas-based metrics derived from human or a few model organisms lack biological interpretability across species with divergent cortical architectures. Here, we investigate sulcal pits--the locally deepest points of cortical folds--as conserved, atlas-independent landmarks that provide a robust basis for cross-species comparison. Using cortical surface reconstructions from 90 mammalian species, we show that sulcal pit distribution patterns partly recapitulate phylogenetic relationships, independent of overall brain size (volume and surface area), and vary systematically with ecology and lifestyle. By tracing pit-based evolutionary trajectories from 80 million years ago to the present, we found pronounced differences across ecological and behavioral categories, indicating that cortical folding has diversified in close association with species habitats, lifestyles, and social structures. Using sulcal pits, we identified Homo sapiens-specific regions and species-shared regions. The Homo-specific areas were functionally associated with higher cognitive and emotional processes, distinguished by unique histological features, enriched for gene sets related to neural regulation, and exhibited markedly different cell-type abundance profiles compared to shared regions. Together, these results establish sulcal pits as a robust, evolutionarily informative feature for cross-species cortical alignment, offering new insights into the structural innovations underlying brain evolution study.

evolutionary biology↗

bioRxiv2025

RNA viruses in water shape the viromes of shrimp and fish in aquaculture systems

Aquatic environments host immense RNA viral diversity, yet the extent to which waterborne viruses influence the virome of aquatic animals remains unclear. Here, we conducted a comprehensive longitudinal metatranscriptomic analysis of water, shrimp, and fish across multiple culture stages in aquaculture systems. We identified 3,211 RNA viruses spanning 21 viral supergroups, with 97.4% representing novel species. Water exhibited the greatest viral diversity (3,093 species), followed by shrimp (1,280) and fish (398), with most viruses detected in shrimp and fish also detected in water. Diversity analyses revealed increasing richness and significant compositional shifts in 92 high-abundance viruses (>1,000 RPM) across culture stages. Viral abundance in aquatic animals was strongly correlated with that in water, and the temporal trajectories of the 16 most abundant viruses were closely synchronized between water and shrimp. Furthermore, 337 virus species were shared among shrimp and two fish species, of which 309 were present in water. These findings demonstrated that RNA viruses in water shape the composition and dynamics of aquatic animal viromes, underscoring the importance of water virome surveillance and management for disease prevention in shrimp aquaculture.

microbiology↗

bioRxiv2025

Targeted α-Synuclein mRNA Degradation by PMO-Based RNA-Degrading Chimeras

-Synucleinopathies are devastating neurodegenerative diseases characterized by pathological accumulation of a neuronal protein, -synuclein (Syn). Lowering soluble Syn levels is a promising therapeutic strategy to limit aggregation and neurotoxicity, but directly targeting this protein is hindered by its intrinsically disordered structure and other factors, such as its conformational heterogeneity and intracellular drug delivery barriers. Consequently, increasing attention has been directed toward targeting the SNCA transcript, which encodes Syn. Here, we developed phosphorodiamidate morpholino oligonucleotide (PMO)-based RNA-degrading chimeras (RDCs) that selectively bind the 5' untranslated region of SNCA mRNA and recruit RNase L for targeted RNA degradation. Through the systematic evaluation of 10 RDCs, we identified and optimized 4-D1, which effectively reduced SNCA mRNA and Syn protein expression in HEK293T cells in an RNase L-dependent manner. 4-D1 lowered SNCA transcript and Syn protein levels in both primary cortical neurons from humanized SNCA mice and in human induced pluripotent stem cell-derived cortical neurons. This reduction prevented prion-like seeding induced by patient-derived Syn fibrils and protected neurons from fibril-induced cytotoxicity. Finally, in vivo studies confirmed the efficacy of 4-D1 in reducing Syn mRNA expression in humanized SNCA mice. These findings indicate that PMO-based RDCs may represent a promising therapeutic modality for -synucleinopathies. Significance StatementAbnormal aggregation of the neuronal protein -synuclein is central to Parkinsons disease and related disorders, yet therapeutic candidates that directly target this protein have yet to demonstrate efficacy. in clinical trials. We developed a new strategy that lowers -synuclein production at the RNA level using phosphorodiamidate morpholino oligonucleotide (PMO)-based RNA-degrading chimeras (RDCs). These molecules recruit a natural RNA-degrading enzyme to selectively destroy the RNA transcript encoding -synuclein. Our lead RDC reduced -synuclein levels in cultured cells, humanized mouse and human neurons, blocked -synuclein pathological aggregation, and protected neurons from toxicity. This study establishes RDCs as a promising therapeutic platform for Parkinsons disease and other neurodegenerative diseases driven by -synuclein.

biochemistry↗

bioRxiv2025

An ultra-long acting insulin enables glucose-synchronised release

Delayed and weak glucose-responsive kinetics, coupled with short plasma exposure and complicated formulation, remain major obstacles to the clinical translation of glucose-responsive insulin formulations. Here we report a rapidly absorbable, ultra-long acting, and glucose-responsive insulin analogue via engineering recombinant human insulin with two phenylboronic acids. The insulin analogue has a long circulating half-life (t1/2{beta} [~]150 h) due to its unique, unprecedented, glucose-responsive binding to blood circulation-associated proteins. This interaction drives the formation of a unique systemic reservoir that allows synchronised dynamic response in insulin levels to glucose fluctuations. In type 1 diabetic mice and minipigs, a single subcutaneous dose can maintain normoglycaemia for over one week (47.5-fold compared to insulin glargine). After the last injection of four consecutive weekly administrations in mice, the glucose-lowering effect can last 800 hours. Administering this glucose-responsive insulin analogue with a fully automated insulin delivery system can leverage dual closed loops and achieve a glucose time in range of over 85% and a coefficient of variation of approximately 30%, better than the recommended targets for human therapy. Importantly, no toxicity was identified in the study.

bioengineering↗

bioRxiv2025

Leptin-Associated Sex Difference in TMJ OA Induced by Metabolic Endotoxemia

Background: Temporomandibular joint (TMJ) osteoarthritis (OA) is a degenerative disease affecting the whole synovial joint, with a higher prevalence in women. Obesity is recognised as a risk factor for knee OA, but its association with TMJ degeneration remains controversial. Lipopolysaccharide (LPS), or endotoxin, has increasingly been proposed as a mediator of obesity-related knee OA. In parallel, adipose-derived leptin played a role in the development of metabolic OA. This study investigated whether chronic LPS exposure induces TMJ OA and whether leptin is involved in this process. Methods: Six-month-old female and male Wistar rats received continuous subcutaneous LPS infusion to induce TMJ OA. At 10 weeks, peripheral blood, white adipose tissue, and TMJs were harvested for biochemical, histological, micro-computed tomography and gene expression analyses. Primary TMJ chondrocytes isolated from healthy rats were used to investigate sex-specific cellular responses to leptin and LPS in vitro. Results: Chronic LPS exposure induced mild, sex-divergent TMJ changes. Compared to same-sex healthy controls, LPS-treated females showed a marginally worse Mankin score (P = 0.053) with greater cartilage glycosaminoglycan loss (P = 0.032), synovitis and subchondral bone deterioration, whereas LPS-treated males only showed worse cartilage surface fibrillation. Both sexes showed subcutaneous adipocyte hypertrophy in response to LPS. Only females progressed to adipose inflammation and plasma leptin elevation (P = 0.018), which correlated strongly with total Mankin score (Spearman rho=+0.773, P = 0.024). Leptin was detected in the joint on chondrocytes co-expressing leptin receptor (OB-R) and inducible nitric oxide synthase (iNOS). The percentage of cells positive for leptin, OB-R and iNOS was differentially abundant in LPS-treated females than in sex-matched controls and LPS-treated males. In vitro, at the same leptin dose, female chondrocytes exhibited lower metabolic activity and greater oxidative stress than male chondrocytes. Notably, leptin upregulated matrix metallopeptidase (MMP)-13 expression only in LPS-primed female chondrocytes. Conclusion: Chronic systemic LPS exposure induced sex-divergent TMJ osteoarthritic pathology, adipose dysfunction and altered leptin signalling. The tissue-level changes were associated with leptin-linked inflammatory cascades amplified in female chondrocytes. These findings suggest that leptin is involved in the pathogenesis of systemic endotoxin-triggered TMJ OA and may partly explain sex differences in OA development.

pathology↗

bioRxiv2025

Dopamine and its receptor DcDop2 are involved in the mutualistic interaction between 'Candidatus Liberibacter asiaticus and Diaphorina citri

Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus huanglongbing, is transmitted by the Asian citrus psyllid Diaphorina citri. While CLas-positive (CLas+) females exhibit increased fecundity and metabolic demands, their neuroendocrine regulation mechanisms remain unclear. We propose CLas manipulates dopamine (DA) signaling to enhance psyllid fecundity and CLas proliferation. Metabolomics revealed elevated DA in CLas+ females. Silencing DA synthesis genes and receptor DcDop2 via RNAi reduced lipid reserves, fecundity, and ovarian CLas titers. Through combined in vivo and in vitro experiments, we demonstrated that the microRNA miR-31a suppresses DcDop2 expression by binding to its 3 untranslated region. Overexpression of miR-31a resulted in decreased DcDop2 expression and CLas titers in the ovaries, eliciting phenotypic defects akin to DcDop2 knockdown. Furthermore, DcDop2 knockdown and miR-31a overexpression reduced juvenile hormone (JH) levels and adipokinetic hormone (AKH) signaling in fat bodies and ovaries. Consequently, CLas regulates the DA-DcDop2 signaling axis to improve D. citri lipid metabolism and fecundity, while simultaneously promoting its replication. These findings reveal a coevolution between CLas proliferation and ovarian development in the insect host. This discovery enhances our understanding of the molecular interplay between plant pathogens and vector insects and offers novel targets and strategies for HLB field management.

ecology↗

bioRxiv2025

Quinolinic acid metabolism may mitigate AKI to CKD transition

The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) remains a significant clinical problem with unclear underlying mechanisms. Emerging evidence suggests that alterations in tryptophan metabolism, particularly in the production of downstream metabolites such as quinolinic acid (QA), play a role in renal pathophysiology. QA is a NAD biosynthesis intermediate metabolized by the enzyme quinolinate phosphoribosyltransferase (QPRT). In this study, we investigated the role of QA in the AKI-to-CKD transition using experimental mouse models and clinical observations and leveraging multiple omics approaches. Systematic metabolomic profiling identified endogenous QA as one of the most significantly elevated metabolites following folic acid-(FA) induced injury. Exogenous QA exacerbated FA-induced kidney dysfunction. Conversely, aged mice deficient in QPRT showed worsened expression of kidney fibrosis markers even in absence of kidney injury, while younger littermates exhibited worsened induced kidney injury. Mice lacking QA-producing enzymes resisted experimental AKI and AKI-to-CKD progression. Multimodal spatial metabolomics analysis of human AKI kidney biopsies revealed QA accumulation in regions of inflammatory infiltration. Finally, children with CKD exhibited higher urinary QA levels compared to healthy controls. These findings underscore QA as a potential mediator of kidney injury and a therapeutic target for preventing the progression from AKI to CKD. One Sentence SummaryQuinolinic acid promotes kidney damage and fibrosis, suggesting it as a contributor of AKI-to-CKD progression and a potential therapeutic target.

pathology↗

bioRxiv2025

Multiple protein-protein interactions drive the assembly and budding of the Chikungunya virion

The assembly of enveloped viruses is a highly orchestrated process that depends on the coupling of multiple protein-protein interactions within a membrane environment. To gain mechanistic insight into this process, we use Chikungunya virus as a model system to study Alphavirus assembly, focusing on the interplay between core-spike and spike-spike interactions. We begin with coarse-grained molecular dynamics simulations to systematically explore how the symmetry of the nucleocapsid core, together with the relative strengths of spike-core and spike- spike interactions, influences budding efficiency and the emergence of icosahedral particle symmetry. Building on these computational predictions, we perform site-directed mutagenesis on Chikungunya virus 181/25 and examine the consequences for particle assembly and budding in cultured cells, as well as the impact of these mutations during in-cellulo assembly. Our results reveal that canonical core-spike interactions, while necessary, are not sufficient for successful assembly. Instead, lateral interactions among glycoproteins emerge as critical determinants of efficient budding, particle stability, and the maintenance of icosahedral symmetry. Together, these findings provide an integrated computational and experimental framework for understanding the molecular principles governing Alphavirus assembly.

biophysics↗

bioRxiv2025

In vivo colonic epithelial cell editing attenuates intestinal inflammation in mice

Engineered epithelial cells with enhanced efferocytosis capacity promote inflammation resolution and restore tissue homeostasis. Here, we developed a therapeutic approach to generate efferocytosis boosting epithelial cells in vivo by delivering mRNA in lipid nanoparticles (LNPs). We demonstrate that LNP-mediated delivery of mRNA enables efficient in vitro and in vivo functional editing of epithelial cells. In murine models of colitis, intraperitoneal administration of mRNA-loaded nanoparticles designed to boost efferocytosis markedly attenuated intestinal inflammation and halted disease progression. This strategy provides a proof of concept that epithelial cells can be functional engineered in situ and represents a promising therapeutic avenue for mitigating inflammatory tissue damage. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/678706v2_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@874991org.highwire.dtl.DTLVardef@1eefbfforg.highwire.dtl.DTLVardef@e22fa6org.highwire.dtl.DTLVardef@1a6480d_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

Synthetic pectin-cellulose nanofiber capsule provides minimal model capturing mechanics of a regenerating plant cell wall

Plant primary cell walls are dynamic supramolecular assemblies composed of layered cellulose, hemicellulose and pectin, progressively built through synthesis and secretion. However, the specific architectural features and structural components sufficient to endow the mechanical properties of the wall remain unclear. Here, we construct a minimal synthetic spherical shell and compare its structural and mechanical properties to those of a plant single-cell system. To eliminate complexities from intercellular connectivity and developmental history, we exploit the ability of plant protoplasts to regenerate cell walls de novo. Compression tests of regenerating protoplasts between parallel plates reveal that wall stiffness increases with wall thickening over time. Despite differences in assembly pathways, architecture, and composition, the synthetic shell exhibits a similar thickness-dependent modulus and similar material stiffness. The synthetic shell, composed of pectin and cellulose layers, mirrors the mechanical behavior of regenerating primary cell walls, suggesting that these components are sufficient to confer key viscoelastic properties in the limit of small deformations. Given the complexity of natural plant cell walls, the synthetic analogue offers a controllable platform to dissect the mechanical contributions of individual wall components.

plant biology↗

bioRxiv2025

Archetype analysis of lung adenocarcinoma premalignancy links heterogeneity in premalignant lesions to diverging features of invasive disease

ABSTRACTLung adenocarcinoma (LUAD), the most common form of lung cancer, is a heterogeneous disease with highly variable histopathologic features and clinical outcomes. LUAD premalignant lesions (PMLs) are localized proliferative lesions of atypical pneumocytes that proliferate along the alveolar walls. In this study, we characterized the molecular heterogeneity across PMLs, regardless of histologic designation, and identified four unique groups or "archetypes" of PMLs using bulk RNA and exome sequencing data from laser captured microdissected PMLs, normal, and tumor tissue from LUAD resection cases. The archetypes were defined based on expression of recurrent gene co-expression modules discovered using the LUAD PMLs we profiled and three publicly available datasets. One PML archetype, termed "proliferation", was associated with increased expression of genes involved in cell proliferation, a pro-tumor immune environment, and enrichment for EGFR driver mutations. Another archetype, termed "normal-like", was associated with similar features to normal tissue, an anti-tumor immune response, and lacked enrichment for driver mutations compared to other archetypes. We projected the PML archetypes into independent gene expression datasets profiling LUAD and found that tumors closest to the proliferation archetype were enriched for multiple features of aggressive LUAD, including high tumor grade and lymph node invasion, and had significantly lower disease-free survival. Proliferation archetype PMLs may represent a subset of lesions with more aggressive features that could improve patient stratification and suggest novel targets for lung cancer interception.

cancer biology↗

bioRxiv2025

Base-editing a single missense mutation in A20 enhances CAR-T cell efficacy

T cell exhaustion limits the efficacy of cancer immunotherapies. Here, we performed genome-wide loss-of-function screening in repetitively stimulated human T cells and identified the mulitfunctional ubiquitin-modifying protein A20/TNFAIP3 as a major negative regulator of exhausted T cell persistence. Protein large language modeling, deep base-editing mutagenesis, and studies in immunocompetent mice with domain-specific inactivating mutations revealed A20s non-enzymatic M1 ubiquitin-binding zinc finger 7 (A20ZF7) motif as critical to suppression of anti-tumor immunity. A20ZF7-deficient CD8+ tumor-infiltrating lymphocytes (TILs) resisted terminal exhaustion and circumvented an unappreciated mechanism restraining perforin degranulation in terminally exhausted cells. Human chimeric antigen receptor (CAR)-T cells engineered via base-editing to inactivate A20ZF7 via a single missense mutation also resisted exhaustion, secreted more perforin and robustly suppressed cancer in vivo. These studies pinpoint A20ZF7 as a novel T cell checkpoint and reveal precision base-editing of missense mutations as an effective approach to enhance CAR-T cell therapy.

immunology↗

bioRxiv2025

ETV2 mediated differentiation of human pluripotent stem cells results in functional endothelial cells for engineering advanced vascularized microphysiological models

Patient-specific microphysiological models, exemplified by organs-on-a-chip and organoids, have become a valuable tool for broad applications, revolutionizing biomedical research. However, limitations persist, with functional vasculature being a significant challenge. Generating functional human induced pluripotent stem cell (h-iPSC) derived endothelial cells (h-iECs) represent an urgent need. With the discovery of ETV2s determinant role in specifying EC lineages during differentiation, researchers have adopted techniques involving ETV2 overexpression to produce h-iECs more efficiently and consistently. However, the capacity of these cells to form functional vasculatures has not yet been thoroughly investigated. Here, we generated multiple h-iPSC lines with inducible ETV2 expression, and subsequently differentiated them into h-iECs, which were validated functionally and by key endothelial markers and RNA-seq analysis. These cells are capable of self-organizing into stable microvascular networks (MVNs) in a microfluidic chip reproducibly, forming lumenized and functional vessels that mimic the in vivo capillary bed in both morphology and function - a result not achieved using h-iECs differentiated with conventional two-step methods using the same h-iPSC lines. Furthermore, complex microphysiological models featuring perfusable vasculature were also successfully developed using ETV2 activated h-iECs, demonstrated with vascularized tumor and blood-brain barrier (BBB) models. Additionally, by pooling genetically engineered h-iPSCs with inducible ETV2, we effectively employed an orthogonally induced differentiation approach to enhance vascularization of an organoid model. Our methodology opens avenues in precision medicine, leading to personalized microphysiological models with perfusable vasculature for various applications.

bioengineering↗

bioRxiv2025

Reward-reset interval timing drives patch foraging decisions through neural state transitions in dorsomedial striatum

Activities with temporally distributed returns require deciding not only what to do, but when to stop. Although optimal foraging theory predicts that patch departure should depend on the total time invested in a patch, behavior across species often reflects sensitivity to recent rewards. The dorsomedial striatum (DMS) mediates both goal-directed decision-making and interval timing, two functions that converge during patch foraging, where animals must decide when to exit patches to maximize reward rates. We recorded extracellular activity from neurons in DMS while freely moving mice performed a patch-foraging task. Mice employed a reward-reset strategy, primarily basing their exit decisions on the time since the last reward, with systematic adjustments for patch residence time and environmental reward-rate context. Individual neurons in DMS underwent discrete firing rate transitions at characteristic delays following each reward. These transition times tiled the post-reward interval across the population, producing an accumulation-to-threshold signal that reset with each reward and whose rate was sensitive to the cost of time, increasing with higher environmental reward rates and as rewards occurred later in the patch. This accumulation reached a consistent threshold at the moment of patch exit, encoding the animals intended stopping time. Together, these results identify a time-cost-variable, reward-reset, accumulation-to-threshold computation in DMS that integrates environmental reward rate, elapsed time from pursuit engagement, and elapsed time from reward occurrence to determine when to abandon a depleting pursuit.

neuroscience↗