Biology subjects

Chen, Y.

Publications and source records attributed to Chen, Y..

At least 253 records · Page 14Linked to original sources

bioRxiv2026

Mid-superior temporal sulcus encodes spatial context and behavioral state in freely moving macaques

Primate neuroscience has traditionally studied the brain under highly constrained conditions, limiting our understanding of neural function during real-world behavior. The mid-superior temporal sulcus (mSTS) is implicated in social perception, but its role during unconstrained behavior has not been tested. Here we performed wireless depth-electrode recordings from both banks of mSTS in macaques freely exploring a large three-dimensional arena, combined with 3D pose tracking and behavioral segmentation. Neural encoding models revealed mSTS firing rates were jointly modulated by spatial position, body kinematics, and geometric visual proxies, preferentially encoded in allocentric coordinates but with a shift toward body-centric encoding during vertical exploration. Neural populations carried decodable information about discrete behavioral syllables, with broad temporal generalization and neural similarity that tracked the sequential structure of behavior. Population manifold analysis revealed that the same behavior occupied different regions of population space at different spatial locations, and population dynamics showed structured organization around behavioral transitions. Together, these results suggest that mSTS populations carry joint information about spatial context and behavioral state during natural behavior.

neuroscience↗

bioRxiv2026

N-3 Polyunsaturated Fatty Acids Ameliorate Post-infarction Cardiac Dysfunction Through Modulation Of Adiponectin-Ceramide Metabolism

BackgroundIt has been shown that n-3 polyunsaturated fatty acids (n-3 PUFA) of marine origin exert significant beneficial effects on myocardial infarction (MI); however, the underlying mechanisms remained unclear. Ceramides play a vital role in the regulation of energy metabolism, mitochondrial function, and apoptosis. Through the integration of clincial studies and animal experiments, this study aimed to determine whether n-3 PUFA improved myocardial function by modulating ceramide metabolism. MethodsIn a case-control study, 100 patients with AMI and 100 healthy pariticipants were enrolled to measure serum ceramide concentrations. Meanwhile, mice were randomly allocated into 4 groups and administrated to a 3-week intervention with n-3 PUFA in triglyceride and phospholipid forms. A mouse model of MI was then established, followed by an additional 4 weeks of continuous intervention. Subsequent comprehensive assessments of cardiac function were performed in the mice. Finally, the mice were euthanized to conduct targeted ceramide lipidomic analysis and other relevant assays. ResultsThe levels of serum C16:0-, C18:0-, C20:0-, C24:1-ceramides and total ceramides in patients with acute myocardial infarction (AMI) were significantly higher compared with the healthy controls. In the murine model of myocardial infarction, pathological analysis via TTC staining demonstrated that interventions with fish oil (triglyceride form) and krill oil (phospholipid form) both significantly reduced myocardial infarct size. Concomitant echocardiographic assessment confirmed that both treatments markedly elevated left ventricular ejection fraction (LVEF), with the magnitude of improvement being significantly superior to that of the model control group. Concurrently, compared with the model group, the concentrations of ceramides in cardiac tissue and serum were significantly lower in the groups with fish oil and krill oil intervention. Western blot analysis further confirmed that n-3 PUFA intervention upregulated adiponectin expression, reduced ceramide accumulation in myocardial tissue, and inhibited mitochondria-mediated cardiomyocyte apoptosis, thereby improving cardiac function and prognosis following myocardial infarction. ConclusionsThis work demonstrates that n-3 PUFA exert cardioprotective effects following MI mediated by adiponectin-ceramide axis. However, there is no significant difference regarding therapeutic efficacy of n-3 PUFA in triglyceride or phospholipid forms.

pharmacology and toxicology↗

bioRxiv2026

Regression-based Modeling of Spearman's Rho for Longitudinal Metabolomics and Mental Wellness in Breast Cancer Patients

SO_SCPLOWUMMARYC_SCPLOWChemotherapy in breast cancer (BC) can substantially affect mental wellness. Advances in metabolomics enable comprehensive profiling of metabolic changes over time during and after treatment, offering insights into biological mechanisms linking chemotherapy to mental health outcomes. To study the association between metabolite profiles and mental wellness, correlation-based analyses are particularly useful. Spearmans rho is a widely used correlation measure and popular alternative to Pearsons correlation, since it also applies to non-linear association between variables. However, existing methods are not designed for longitudinal data and do not allow for covariate adjustments. In this paper, we propose a novel regression-based framework grounded in a class of semiparametric models, the functional response models, to extend this popular correlation measure to longitudinal settings with missing data under the missing at random assumption. This framework facilitates inferences about temporal changes in correlations over time and association of explanatory variables for such changes. We use simulation studies to evaluate performance of the approach with moderate sample sizes. We apply the approach to a one-year longitudinal substudy of the EPIGEN study to examine the longitudinal association between metabolite profiles and mental wellness in BC patients undergoing chemotherapy. The identified metabolites may serve as candidates for future in-depth bioinformatics analyses and translational investigations.

cancer biology↗

bioRxiv2026

U-Probe: universal agentic probe design for imaging-based spatial-omics

Probe design for fluorescence in situ hybridization (FISH) underpins spatial transcriptomics, three-dimensional genome studies, and clinical diagnostics, yet remains constrained by two challenges: dependence on expert knowledge for parameter selection and quality evaluation, and the inability of existing tools to accommodate the diverse probe architectures introduced by rapidly emerging methods. Here we present U-Probe, a universal and agentic probe design platform. U-Probe employs a declarative configuration system with a directed acyclic graph (DAG)-based assembly engine that supports arbitrary probe structures from established protocols such as MERFISH, seqFISH, and MiP-seq to entirely novel architectures without code modifications. Integrated LLM-based AI agents enable conversational design workflows, allowing users to specify experimental goals in natural language and receive synthesis-ready probe sequences. We validated U-Probe in three scenarios: agent-driven MiP-seq panel design for influenza-infected mouse lung tissue, genome-tiling DNA-FISH for herpesvirus detection, and a novel RCA-based ligation probe for single-nucleotide mutation discrimination. U-Probe is available as an open-source tool with CLI, Web, and agent interfaces.

bioinformatics↗

bioRxiv2026

An orthogonal near-infrared optical switch for wireless neuromodulation in freely behaving mice

Modulating neuronal activity with light is a powerful tool for neuroscience research. However, currently available technologies often require invasive fibers for delivery of visible light, causing tissue damage and limiting behavioral studies. Although near-infrared (NIR) neuronal modulation improves tissue penetration depth, sustained NIR illumination during neuromodulation raises significant concerns about photothermal effects. Here, we introduce a dual-wavelength near-infrared switch (Dual-NIR Switch) that uses two transcranial NIR inputs to initiate and terminate neuronal activation, enabling tether-free neuromodulation in freely moving mice. Dual-NIR Switch employs orthogonal dichromatic upconversion nanoparticles that emit blue and green light under 980 nm and 808 nm excitation, respectively, to activate and inactivate the step-function opsin SOUL. Therefore, transient 980 nm NIR illumination initiates neuronal excitation, which will remain excited without further stimulation but will be rapidly terminated on demand by a subsequent 808 nm illumination. Upon transcranial 980 nm and 808 nm NIR illuminations in freely moving mice, we achieve on-demand control of behavioral paradigms across tunable timescales, ranging from seconds to minutes and even extending to sub-hour durations. By eliminating the need for sustained NIR irradiation, Dual-NIR Switch offers an on-demand, duration-tunable neuromodulation tool for both basic neuroscience and potential therapeutic applications in treating brain diseases.

neuroscience↗

bioRxiv2026

A Brain-wide Neuronal Spiking and Behavior Dataset for Working Memory-Specific Activation and Reactivation in Mice

AbstractHow do millisecond-scale neural activities mediate multi-second behaviors such as working memory? This dataset provides brain-wide, high-spatiotemporal-resolution single-unit spiking activity recorded from 40 head-fixed mice performing an olfactory delayed paired-association (ODPA) task, encompassing 33,028 neurons across 62 anatomically defined brain regions. Utilizing this dataset enables the extraction of millisecond-scale within- and cross-region spike couplings enriched among memory-content-selective neurons. These couplings may be used to identify higher-order, hierarchically structured activity motifs. Because these multi-neuron patterns are captured both during active task performance and spontaneous inter-trial intervals, this dataset provides a resource for studying replay-related activity and for testing hypotheses about circuit-level processes associated with perceptual working memory. The dataset supports broad investigations into cross-regional spike organization, functional coupling, and temporal coding in working memory circuits.

neuroscience↗

bioRxiv2026

An EEG-fMRI Jointly Constrained Digital Twin Brain and Its Application in Alzheime's Disease

Current digital twin brain (DTB) models are typically optimized using single-modality functional neuroimaging data, which restricts their ability to simulate brain dynamics across multiple spatiotemporal scales. Here, we bridged this gap by developing a two-stage DTB (TS-DTB) modeling framework jointly constrained by functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) data. Validation in both the healthy young and Alzheimers disease (AD) cohorts demonstrated that the TS-DTB model simultaneously captures subject-specific features of multi-scale brain dynamics. In particular, the TS-DTB models of AD patients successfully recapitulated spectral-temporal signatures of cognitive decline, mechanistically linking these deficits to excitation-inhibition (E-I) imbalances. By simulating responses to repetitive transcranial magnetic stimulation (rTMS), we further revealed that cognitive recovery in AD patients can be driven by E-I rebalancing via synaptic reconfiguration and background suppression. Overall, these findings underscore the potential of the TS-DTB to advance the mechanistic understanding of the brain and inform personalized digital therapeutics.

neuroscience↗

bioRxiv2026

Cellular hydraulics ensures robust endothelial-to-haematopoietic transition

Haematopoietic stem and progenitor cells (HSPCs) emerge from specialised haemogenic endothelial cells (HECs) in the ventral wall of the dorsal aorta (VDA) through a process known as endothelial-to-haematopoietic transition (EHT). During EHT, elongated HECs undergo actomyosin-driven rounding and extrusion, a mechanically demanding transformation that requires cell integrity to be maintained. Here, we identify an osmo-hydraulic volume-regulation mechanism that enables HECs to adapt to and withstand this mechanical challenge. Haemodynamic forces increase Piezo-dependent calcium ion activity in ventral endothelial cells, while Piezo activation promotes HEC swelling. Combined genetic and pharmacological analyses support a pathway in which Piezo-mediated swelling triggers VRAC-dependent osmolyte efflux and Aqp1a.1-mediated water efflux to reduce HEC volume. Disrupting either osmolyte or water efflux causes excessive HEC swelling, compromises HEC integrity and reduces HSPC production. Together, our findings establish osmo-hydraulic volume regulation as a mechanism that preserves cellular robustness during EHT and support a model in which aquaporins act as pressure-relief valves, dissipating intracellular hydrostatic pressure to sustain HEC survival and definitive haematopoiesis.

cell biology↗

bioRxiv2026

Single-cell lineage tracing maps clonal and transcriptional dynamics in melanoma metastasis

Melanoma metastasis is driven by extensive intratumoral heterogeneity and phenotypic plasticity, yet how clonal identity relates to transcriptional programs during metastasis remains unclear. Here, we applied MeRLin, a single-cell lineage tracing platform, to dissect the clonal and transcriptional heterogeneity of metastatic melanoma in a patient-derived spontaneous metastasis model. Clonal analyses revealed hierarchical structures during tumor progression, with a subset of lineages from primary tumors consistently enriched across metastatic sites, supporting a model of polyclonal seeding followed by selective expansion of pre-existing highly metastatic subpopulations. Single-cell transcriptomic profiling identified two major metastatic subpopulations of distinct transcriptional programs, characterized by neural crest stem cell-like and lipid metabolism signatures. Both programs were enriched for invasion-associated genes and maintained across organs through distinct regulatory networks. Spatial mapping by barcode RNA-FISH linked these transcriptional states to their tissue context and showed that OLFML3 expression partially co-localized with a dominant subpopulation at the tumor-liver interface, marking the invasive fronts of metastatic growth. Together, these findings establish a framework in which clonal identity, transcriptional state, and spatial organization jointly shape metastatic melanoma progression.

cancer biology↗

bioRxiv2026

Introducing the digital PCR data essentials standard to harmonize data structure for clinical and research use

Digital PCR (dPCR) is a powerful technology for absolute quantification of nucleic acids, valued for its accuracy, sensitivity, and repeatability. Yet, the commercialization of different instruments with proprietary software has introduced challenges to data analysis, interoperability, and comparability. Therefore, we present the Digital PCR Data Essentials Standard (DDES) - a lightweight, human- and machine-readable, and cross-platform data standard developed in collaboration with the dPCR community. The standard consists of three file types designed to enable both manual inspection and automated analysis: (i) a main file summarizing experiment and reaction-level (meta-)data; (ii) an assay file describing targets and detection chemistry, and (iii) intensity files capturing partition-level raw fluorescence data per reaction. DDES supports a wide range of current dPCR applications, including singleplex and multiplex assays, endpoint and real-time readouts, and will be curated to implement future dPCR developments. By harmonizing the data structure, DDES lays out the foundation for FAIR dPCR data practices and supports improved software compatibility, collaborative and reproducible research, and future dPCR data repositories.

bioinformatics↗

bioRxiv2026

A Fungal Natural Product that Targets Cellulose Synthase Complex and Inhibits Plant Cellulose Biosynthesis

Cellulose, a primary component of plant cell walls, is synthesized by cellulose synthase complexes (CSCs) at the plasma membrane. Targeting this process with cellulose biosynthesis inhibitors (CBIs) has significantly advanced our understanding of plant cell wall formation and provided valuable compounds for herbicide development. Here, we identified a fungal natural product, 8-methyldichlorodiaporthin (MDD), as a broad-spectrum plant CBI. Structure-activity relationship analyses demonstrate that methylation modifications on the isocoumarin ring and chlorination of side chain are crucial for MDD-induced growth inhibition. A chemical forward genetic screen in Arabidopsis thaliana revealed two semi-dominant CESA1 mutations, causing A903T and H1024Y substitutions, that confer insensitivity to MDD. Both mutations locate to transmembrane domains of CESA1, and we show that MDD depletes CSCs from the plasma membrane and reduces cellulose content. Further genetic analyses indicate that the cesa1mddi1-1 A903T mutant also confers resistance to CBIs quinoxyphen and C17, but not to CBIs isoxaben, indaziflam, or ES20. Stacking additional point mutations conferring resistance to other CBIs, cesa3ixr1-1 G998D, and cesa6es20-r3 G935E into the cesa1mddi1-1 A903T background yields multiple-drugs resistant lines that maintain normal growth. These findings establish MDD, as a novel, natural CBI that likely targets CESA1, thereby extending our understanding of CSC regulation and abilities to develop multi-drugs resistant crop varieties. These findings offer new perspectives for weed management and plant biotechnology. Significance StatementCellulose, a fundamental structural component of plant cell walls, is synthesized by cellulose synthase complexes (CSCs) and represents a critical herbicide target. While synthetic cellulose biosynthesis inhibitors (CBIs) like isoxaben and quinoxyphen have helped in the elucidation of CSC function and aided in weed control, natural CBIs remain largely undiscovered. Here, we identify 8-methyldichlorodiaporthin (MDD), a fungal-derived isocoumarin natural product, as a CBI that inhibits plant growth by depleting CSCs from the plasma membrane. Genetic screens reveal MDD-resistant cesa1 mutations, and combining these with other CBI-resistant alleles yields multi-herbicide resistant plants that can grow normally. This research enhances our understanding of cellulose biosynthesis and paves the way for multi-herbicide resistant crops with agricultural benefits.

plant biology↗

bioRxiv2026

Continental-scale multi-omics reveals a distinct microbial-viral biome in sandy beach ecosystems structured by tidal zonation

Sandy beaches are dynamic coastal interfaces shaped by strong physical forcing and intense exchange between marine and terrestrial environments, yet their microbiomes remain poorly resolved at the genomic scale. Here we present a genome-resolved survey of microbial and viral communities across sandy beaches spanning a continental-scale latitudinal gradient along the Chinese coastline. By integrating cross-shore sampling, coastal geochemistry and large-scale multi-omics, we generated 978 metagenomes, 63 viromes and 72 metatranscriptomes, reconstructing 13,337 metagenome-assembled genomes and 38,255 viral populations. Sandy beach microbiomes exhibit exceptionally high genomic novelty, with more than 90% of species-level genomes representing previously undescribed taxa, suggesting that permeable coastal sediments constitute a distinct microbial and viral reservoir. Tidal zonation emerged as a dominant ecological driver structuring microbial diversity, metabolic strategies and virus-host interactions across cross-shore gradients. Genome-resolved analyses revealed systematic metabolic shifts from oxic heterotrophy in supratidal sediments toward increasingly chemolithotrophic and autotrophic pathways toward the low-intertidal and subtidal zone. Sandy beach microbiomes further encode broad potential for hydrocarbon and plastic transformation, together with diverse biosynthetic and antibiotic resistance repertoires that may mediate microbial chemical interactions. Together, these findings identify sandy beaches as a previously under-recognized microbial-viral biome shaped by tidal forcing, providing insight into microbiome evolution and coastal ecosystem resilience under increasing anthropogenic pressure.

microbiology↗

bioRxiv2026

A Nonlinear Biomechanical Model for Prognostic Analysis of Clavicle Fractures

Clavicle fractures often exhibit markedly different clinical outcomes: some patients recover acceptable function despite shortening or displacement, whereas others with apparently similar deformity develop persistent pain, functional loss, or poor healing. To explain this distinction, we propose a minimal nonlinear mechanical model for prognostic analysis of clavicle fractures. The model describes the interaction between fracture-related shortening and compensatory shoulder-girdle posture through a reduced equilibrium equation incorporating stiffness, geometric nonlinearity, and shortening-posture coupling. Within this framework, we analyze equilibrium branches, local stability, and the emergence of critical thresholds. We show that post-fracture destabilization can be interpreted as a fold bifurcation, while more complex parameter dependence gives rise to cusp-type structures and multistability. These bifurcation mechanisms provide a mathematical explanation for sudden deterioration after injury or treatment, as well as for strong inter-individual variability. We further introduce an optimization principle based on a utility functional to guide treatment planning. The analysis predicts that the optimal safe correction should lie strictly below the bifurcation threshold, thereby generating a natural safety margin. Although the model is simplified and has not yet been calibrated against patient data, it nevertheless provides a theoretical framework for understanding why fracture prognosis may deteriorate abruptly near critical mechanical conditions and offers a dynamical-systems interpretation of empirical treatment thresholds used in clinical practice.

bioengineering↗

bioRxiv2026

Visual Emotion Perception in a Deep Neural Network Model with Both Bottom-Up and Top-Down Connections

Emotion reshapes perception by modulating sensory processing through top-down feedback--a process referred to as emotional perception. The computational mechanisms by which distinct affective signals influence visual representations however remain poorly understood. Here, we use a deep neural network to simulate this process and test mechanistic hypotheses about how top-down feedback guides emotional peception. Most existing models treat the perception of emotional content as a static, feedforward task, overlooking the dynamic interplay between internal states, external goals, and sensory input that characterizes affective perception in the brain. We introduce EmoFB, a biologically inspired model that integrates an affective system with a visual processing hierarchy through two functionally distinct feedback signals: intrinsic feedback, arising from the models own affective appraisal of perceptual input, and external steering, conveying contextual priors such as task expectations or target categories. We evaluated EmoFB on three tasks varying in perceptual ambiguity (Single Image, Side-by-Side, and Overlay). External steering exerted the strongest influence, not only improving recognition under challenging conditions but also restructuring internal representations by sharpening category-specific clustering in feature space. Crucially, top-down feedback increased brain-model representational similarity, strengthening alignment with human fMRI responses across early visual cortex, ventral visual areas, and the amygdala. EmoFB provides a computational framework for testing neurocognitive theories of emotion appraisal and top-down feedback modulation. It bridges affective neuroscience and artificial intelligence, offering mechanistic insight into how emotional signals shape perception in both brains and machines.

neuroscience↗

bioRxiv2026

Looplook: An integrative suite for target assignment and functional annotation of chromatin interactions empowered by expression-aware refinement and connected components clustering

Deciphering target genes regulated by cis-regulatory elements (CREs) is critical for translating genetic and epigenomic findings into clinically actionable insights. However, linking distal CREs to their cognate target genes remains a fundamental challenge due to the limited availability of computational tools for spatial annotation and the oversimplified assignments inherent to conventional topology-only strategies. A flexible framework that integrates 3D proximity with transcriptional output is urgently needed. To address these limitations, we develop looplook, an integrated computational framework that bridges 3D chromatin topology with functional genomics to enable accurate, flexible, and user-driven CRE-target gene assignment. Looplook provides four core capabilities: (1) robust consensus building for denoising and consolidating replicated or multi-source chromatin loops by employing connected component clustering; (2) bidirectional spatial annotation between 3D chromatin loops and diverse linear genomic features, offering optional graph-based high-order discovery and a linear fallback for gapless network resolution; (3) an expression- or chromatin-aware refinement algorithm that selectively retains functional loops; and (4) automated downstream functional profiling seamlessly integrated with customizable multi-track visualization. Through case studies of the FOSL2 and BRD4 cistromes in liposarcoma cells, we demonstrate that looplook outperforms conventional linear annotation methods by integrating chromatin interactions with expression data and chromatin profiles, offering a powerful and valuable framework for distilling experimental omics data into functionally interpretable high-order gene regulation networks. looplook is freely available as an open-source R package, with source code and documentation hosted on GitHub, and will be distributed via the Bioconductor repository.

bioinformatics↗

bioRxiv2026

Structural Mechanism of TRPC3 Channel Activation by the Moonwalker Mutation

TRPC3 is a calcium-permeable, non-selective cation channel that is activated by DAG. It is expressed in several tissues, especially in the cerebellum, and has been implicated in various human diseases. Despite recent progress in understanding the structural mechanism of TRPC3, how the channel opens remains elusive. Here, we present structures of hTRPC3 in an agonist-free resting state, determined using a DAG-binding site mutant. We also present the structure of hTRPC3 in a DAG-bound open state, determined using a constitutively active "moonwalker" (T561A) mutant. These structures, together with electrophysiological results, reveal that the T561A mutation activates hTRPC3 by disrupting a polar interaction with N652. A newly formed {pi}-bulge in S6 leads to rotation and outward tilting of the lower half of S6, resulting in dilation of the pore and thus channel opening. Agonist DAG stabilizes hTRPC3 in the open conformation. BTDM exerts its inhibitory effect by pushing S5 and S6 back to the center to close the pore, while preserving the {pi}-bulge. These results shed light on the opening mechanism of hTRPC3.

biophysics↗

bioRxiv2026

Expanding the scope of redox-balance growth coupling techniques with a carbon cofeeding strategy

Metabolic engineering to produce molecules not naturally synthesized by the host often requires directed evolution to improve pathway enzyme performance. Growth-coupled selection can dramatically increase directed-evolution throughput, and manipulation of redox balance has proven effective for tying reductase fitness to microbial growth. However, most redox-balance selections require feeding the reductase substrate because of stoichiometric constraints. This is impractical for many biosynthetic pathways either due to practical limitations on cost or complexity of bulk substrate synthesis, or the lack of an ability to transport substrate into cells, for example intracellular acyl-CoA/ACP intermediates. Here we define stoichiometric constraints that make substrate feeding necessary for many acetyl-CoA-derived reduction pathways in NADPH-imbalanced hosts. We overcome these constraints with a dual-feedstock strategy in which glucose provides reducing power while acetate supplies additional acetyl-CoA without directly perturbing redox balance. In an engineered E. coli selection strain, acetate co-feeding enabled growth coupling of acetaldehyde, 3-hydroxybutyrate, and mevalonate production and produced a linear correlation between product formation and growth. We then used this selection to evolve a class II HMG-CoA reductase (HMGR) from Delftia acidovorans toward NADPH utilization, enriching variants with improved NADPH-dependent activity. Finally, propionate co-feeding enabled growth coupling of propionyl-CoA reduction, supporting the generality of carbon co-feeding for selecting enzymes in pathways involving acyl-chain elongation and reduction. HighlightsO_LIStoichiometric limits of redox-balance growth coupling are defined C_LIO_LIAcetate co-feeding supplies acetyl-CoA without perturbing redox balance C_LIO_LICo-feeding enables growth coupling of acetaldehyde, 3-HB, and mevalonate C_LIO_LIGrowth coupling enables evolution of HMGR toward NADPH specificity C_LIO_LIPropionate co-feeding extends growth coupling to additional acyl-CoA substrates C_LI

bioengineering↗

bioRxiv2026

Activation of DMH GABAergic neurons, but not local GABAergic AgRP neurons, attenuates chronic stress-induced POMC neuron hyperactivity

Identifying the neural circuits engaged and reshaped by chronic stress is critical for understanding how adaptive responses shift to maladaptive behaviors that contribute to stress-related disorders. Our previous work demonstrates that chronic unpredictable stress (CUS) induces a persistent increase in the firing activity of proopiomelanocortin (POMC) neurons in the arcuate nucleus (ARC). This hyperactivity is due, in part, to a reduction in GABAergic synaptic transmission onto POMC neurons, indicating a disruption in inhibitory control. However, the sources of GABAergic inputs responsible for this effect of chronic stress are unknown. Although AgRP neurons provide local GABAergic input onto POMC neurons and are suppressed by chronic stress, chemogenetic activation of AgRP neurons during stress exposure failed to reduce POMC neuron hyperactivity. GABAergic projections originating from the dorsomedial hypothalamus (DMH) represent another source of inhibitory input to POMC neurons. We found that CUS decreased the firing activity of DMH GABAergic neurons with sex differences, with females exhibiting greater vulnerability to stress-induced suppression. Chemogenetic activation of these neurons during chronic stress markedly attenuated POMC neuron hyperactivity in both sexes, indicating that DMH GABAergic neurons function as a critical upstream regulator of POMC neuron activity under chronic stress. These findings suggest that reduced inhibitory input from DMH GABAergic neurons, rather than local GABAergic AgRP neurons, drives POMC neuron hyperactivity. The weakening of the DMHGABA[->]ARCPOMC circuit activity may represent a novel mechanism underlying maladaptive stress responses and a potential therapeutic target for stress-related disorders.

neuroscience↗