Search bioRxiv⌕ Search

Biology subjects

Wang, D.

Publications and source records attributed to Wang, D..

At least 163 records · Page 9Linked to original sources

scRGP: Prediction of Single-cell Genetic Perturbation Transcriptional Responses based on Rank in Multiple Scenarios

Single-cell perturbation sequencing technologies (e.g., Perturb-seq, CROP-seq), which integrate CRISPR-based gene editing with single-cell transcriptome profiling, have revolutionized the analysis of transcriptomic changes induced by genetic perturbations at single-cell resolution. These technologies serve as a powerful tool for identifying key genes that inhibit tumor growth or reverse cancer cell phenotypes. However, they face two major challenges: data explosion with high experimental costs, and data complexity characterized by high dimensionality, noise, sparsity, and heterogeneity. To address these challenges, we developed the single-cell Rank-based Genetic Perturbation predictor (scRGP), the first deep learning framework leveraging gene expression rank-order information for this task. scRGP demonstrates superior performance in terms of robustness, cross-cell-line perturbation prediction, and high-throughput screening. Specifically, scRGP achieves an approximately 10-16 percentage points improvement in Pearson correlation coefficient (PCC) over state-of-the-art methods (e.g., GEARS and scFoundation) for single- and double-gene perturbation predictions, while also extending prediction capability to triple-gene perturbations. Furthermore, it outperforms these methods by approximately 5-9 percentage points in cross-cell-line predictions. These advancements promise to shift the paradigm of single-cell perturbation studies from experiment-driven to computation-driven approaches, providing new support for functional genomics and precision medicine.

bioinformatics↗

BEST4/CA7+ and goblet cells are interdependent regulators of intestinal mucus homeostasis

The intestinal mucus layer is essential for the integrity of the intestinal barrier. It is produced by goblet cells, whose depletion is common in colonic inflammation but remains poorly understood. Here, we show that goblet cell survival relies on a reciprocal dependence with newly discovered BEST4/CA7+ cells. We developed a method to follow BEST4/CA7+ and goblet cells in time from birth to death in human colon organoids. Notably, goblet cells induce BEST4/CA7+ fates in sister cells and other neighbors, using DLL1-mediated lateral activation of Notch-signaling. BEST4/CA7+ cells in turn promote goblet survival, with the latter depleting rapidly after differentiation in absence of BEST4/CA7+ cells. This apoptosis inhibition does not require direct cell-cell contact and instead depends on their shared lumen. Such differentiation and survival interdependencies may be relevant beyond the maintenance of mucosal homeostasis.

cell biology↗

Prediction of TdP Arrhythmia Risk Through Molecular Simulations of Conformation-specific Drug Interactions with the hERG K+, NaV1.5, and CaV1.2 Channels

Unintended block of cardiac ion channels, particularly hERG (KV11.1), remains a key concern in drug development as disruption of ion channel function can lead to deadly arrhythmia. To assess proarrhythmic risk, we investigated how drugs interact with hERG in its open and inactivated states and whether drug interactions with other cardiac channels like NaV1.5 and CaV1.2 mitigate that risk. Using cryo-EM structures, we modeled open and inactivated conformations of these channels with Rosetta and AlphaFold. We then applied Site Identification by Ligand Competitive Saturation (SILCS), a physics-based pre-computed ensemble docking method, to predict drug binding affinities. SILCS leverages molecular simulation-generated free energy maps for high-throughput docking against hydrated lipid bilayer-embedded ion channel models. Bayesian machine learning was used to refine SILCS scoring using experimental IC50 values from 69 known hERG blockers outperforming Schrodinger Glide, AutoDock Vina, and OpenEye FRED drug docking predictions. Computed drug binding affinities for hERG and CaV1.2 channels were used to train machine learning models that successfully classified around 300 drugs from the CredibleMeds database. Cationic nitrogen SILCS fragment free energy scores were found to be top physical properties that are predictive of drug-induced Torsades de Pointes (TdP) arrhythmia risk. This approach, which relies on the predicted binding free energies and predicted physical properties of drugs rather than the chemical structure of the drugs themselves as features could be extended to facilitate the design of new drugs where rapid assessment of arrhythmia risk can be performed prior to experimental testing.

biophysics↗

The Hypothalamic-Pituitary-Adrenal Axis Orchestrates Energy Homeostasis during Cold Exposure

Cold exposure stimulates the sympathetic nervous system (SNS) to activate brown fat thermogenesis and maintain optimal body temperature, while simultaneously triggering compensatory hyperphagia to restore energy balance. The mechanisms coordinating energy expenditure and intake, however, remain unclear. Here, we reveal that the hypothalamic-pituitary-adrenal (HPA) axis plays a dual role in this process: endogenous adrenocorticotropic hormone (ACTH) directly stimulates the melanocortin-2 receptor (MC2R) in brown adipocytes to promote thermogenesis, whereas glucocorticoids drive cold-induced hyperphagia and act permissively to enhance ACTH-mediated energy expenditure. These findings uncover previously unrecognized functions of the HPA axis and a delicate hormonal interplay that orchestrates energy homeostasis during cold stress. Targeting these pathways may offer novel strategies to mitigate hyperphagic responses associated with increased energy expenditure, with potential implications for obesity treatment. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=184 HEIGHT=200 SRC="FIGDIR/small/677113v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@1ac072forg.highwire.dtl.DTLVardef@10bc88corg.highwire.dtl.DTLVardef@9b9b5corg.highwire.dtl.DTLVardef@1f4e276_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIThe HPA axis orchestrates cold adaptation. C_LIO_LIACTH activates brown fat thermogenesis in vitro and in vivo via activating MC2R. C_LIO_LIGlucocorticoids drive cold-induced hyperphagia. C_LIO_LIGlucocorticoids have a permissive effect on ACTH function in brown adipocytes. C_LI

physiology↗

Perinatal Lead (Pb) Exposure Increases Mouse Embryonic Weight and Alters Neuronal Gene Expression

Acute and chronic exposure to lead (Pb) during pregnancy is linked to adverse health outcomes, including delayed neurodevelopment in offspring. However, the pathways by which Pb exposure influences long-term health remain poorly understood. To address this, we measured the effects of perinatal Pb exposure on gene expression including imprinted genes, X-linked genes, and sexually dimorphic genes. Female mice were given control or Pb acetate dosed (32 ppm) drinking water two weeks prior to timed mating until embryonic day (E)10-12, upon which whole embryos were collected, weighed, and sexed at E13-15. From a subset of embryo heads (n[&ge;]9 per sex per group), we extracted and sequenced RNA. We used linear regression to assess Pb impacts on embryonic weight and gene expression across all mice and stratified by sex. Among the differentially expressed genes, we identified significantly enriched pathways. Pb-exposed embryos weighed more than controls (p=0.007), across both sexes. Collectively, we identified 2,920 differentially expressed genes (FDR<0.05), including 31 imprinted genes and 120 X-linked genes upon Pb exposure. Pb exposure altered expression in gene pathways related to neuronal structure and function as well as sexually dimorphic genes (44 for females; 76 for males). These findings highlight perinatal Pb-linked alterations that may drive later-life health outcomes.

genetics↗

A ratio-based framework using Quartet reference materials for integrating long- and short-read RNA-seq

Long-read RNA sequencing (lrRNA-seq) enables full-length transcript profiling but is confounded by technical batch effects that compromise quantification and prevent data integration across platforms, protocols, and laboratories. The lack of a transcriptome-wide biological ground truth has hindered objective benchmarking. To address these dual challenges, we leveraged certified Quartet reference materials to generate one of the largest multi-center lrRNA-seq resources to date: over one billion long reads from 144 libraries across four PacBio and Nanopore protocols in four independent laboratories. We first establish that ratio-based quantification against built-in reference samples effectively removes technical noise, revealing underlying biological signals. We then constructed the first ratio-based reference datasets for full-length transcripts-- comprising 10,218 isoforms and 6,032 alternative splicing (AS) events--and orthogonally validated them with RT-qPCR. Finally, a comprehensive benchmark using these ground truths reveals that a hybrid strategy integrating long- and short-read data (hybrid-seq) achieves the highest quantification accuracy for both isoforms and AS events. Our work provides a foundational framework and resource for evaluating lrRNA-seq technologies and accelerating the standardization of full-length transcriptomics for research and clinical applications.

genomics↗

Epigenomic Heterogeneity of Non-Functional Pancreatic Neuroendocrine Tumors Uncovered by Single nucleus and Spatial ATAC Profiling

Non-functional pancreatic neuroendocrine tumors (NF-PanNETs) account for the majority of neuroendocrine neoplasms arising in the pancreas and exhibit substantial clinical and biological heterogeneity, yet their epigenetic regulation and spatial architecture remain poorly understood. Here, we present an integrative study of NF-PanNETs across multiple tumor grades using single-nucleus ATAC-seq (snATAC-seq) and spatial ATAC-seq. snATAC-seq delineates the chromatin accessibility landscapes of distinct tumor subtypes, immune cells, and cancer-associated fibroblasts (CAFs), revealing key transcription factor (TF) programs that drive tumor progression and shape microenvironmental interactions. Spatial ATAC-seq further identifies two distinct tumor-stroma ecological niches: a proliferative niche marked by MYC and FOX family, and an invasive niche enriched for Snail family TFs and KRAS pathway activity. These findings demonstrate that cellular behavior in NF-PanNETs is governed not only by intrinsic epigenetic states but also by spatial context. Together, our study provides a spatially resolved epigenomic framework for dissecting NF-PanNET heterogeneity and evolution, offering new biomarkers and regulatory axes for molecular stratification and precision therapy.

cancer biology↗

Genetic inhibition of IL-12β suppresses systolic overload-induced cardiac inflammation and heart failure development

Inflammation promotes heart failure (HF) development, and inhibition of IL-12{beta} simultaneously attenuates interleukin-12 (IL-12) and interleukin-23 (IL-23), two important proinflammatory cytokines. In this study, we used IL-12{beta} knockout (KO) mice to test the hypothesis that genetic inhibition of IL-12{beta} would attenuate transverse aortic constriction (TAC)-induced cardiac inflammation, hypertrophy, and dysfunction, as well as the consequent lung remodeling. IL-12{beta} KO in male and female mice significantly attenuated TAC-induced cardiac dysfunction as evidenced by improved left ventricular (LV) ejection fraction and fractional shortening. IL-12{beta} KO also significantly ameliorated the TAC-induced increase of LV weight, left atrial weight, lung weight, right ventricular (RV) weight, and their ratios to body weight or tibial length in male and female mice. In addition, IL-12{beta} KO significantly attenuated TAC-induced LV leukocyte infiltration, cardiomyocyte hypertrophy, fibrosis, and the consequent lung inflammation and remodeling. Moreover, IL-12{beta} KO reduced TAC-induced alterations of LV gene profile associated with inflammation and fibrosis, as shown by bulk LV RNA sequencing. Furthermore, we found that IL-12{beta} KO significantly attenuated TAC-induced LV accumulation of multiple immune cell subsets, activation of CD4+ and CD8+ T cells, and the percentage of central memory CD4+ and CD8+ T cells in the cardiac drainage lymph nodes. Finally, IL-12{beta} KO mice showed significantly reduced IFN{gamma}+CD8+ and CXCR3+CD8+ T cells in the drainage lymph nodes as compared with WT after TAC. These findings collectively demonstrate that IL-12{beta} plays a critical role in systolic overload-induced LV inflammation, remodeling, and dysfunction, likely through cardiac immune cell infiltration.

physiology↗

Enteric ChAT-expressing neurons as new target for Lactobacillus plantarum ameliorates inflammatory bowel diseases

The gut microbiota plays a crucial role in inflammatory bowel diseases (IBD), yet how specific microbial components influence disease progression remains incompletely understood. Our study reveals that decreased abundance of Lactobacillus species correlates with ulcerative colitis severity in patients. Among tested strains, L. plantarum A736, isolated from traditional fermented foods, demonstrated remarkable efficacy in ameliorating dextran sulfate sodium (DSS)-induced colitis in a mouse model. Strikingly, multi-omics analysis revealed that L. plantarum A736 uniquely enhances choline acetyltransferase-expressing (ChAT+) neurons in the enteric nervous system and elevates acetylcholine (ACh) levels. Further analysis identified that L. plantarum A736 metabolizes tryptophan to produce indole-3-lactic acid (ILA), and supplementation with ILA significantly mimics this strains anti-inflammatory effects by activating ChAT+ neurons. Crucially, selective ablation of colonic ChAT+ neurons completely abolished the therapeutic benefits of both L. plantarum A736 and ILA, establishing their essential role in mediating these effects. These findings demonstrate for the first time that microbial metabolites can directly modulate enteric neuronal circuits to regulate gut immunity. The identified ILA-ChAT+ neuron axis represents a novel neuro-immune pathway that could be targeted for IBD treatment. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/673902v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@1e0d3c5org.highwire.dtl.DTLVardef@16f5481org.highwire.dtl.DTLVardef@152283org.highwire.dtl.DTLVardef@18cfad0_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

The impact of carotenoid energy levels on the exciton dynamics and singlet-triplet annihilation in the bacterial Light-Harvesting 2 complex

The light-harvesting 2 (LH2) complex of purple phototrophic bacteria plays a critical role in absorbing solar energy and distributing excitation energy. Exciton dynamics within LH2 complexes are controlled by the structural arrangement and energy levels of the bacteriochlorophyll (BChl) and carotenoid (Car) pigments. However, there is still debate over the competing light-harvesting versus energy-dissipation pathways. In this work, we compared five variants of the LH2 complex from genetically modified strains of Rhodobacter sphaeroides, all containing the same BChls but different Cars with increasing conjugation: zeta-carotene (N=7; LH2Zeta), neurosporene (N=9; LH2Neu), spheroidene (N=10; LH2Spher), lycopene (N=11; LH2Lyco), and spirilloxanthin (N=13; LH2Spir). Absorption measurements confirmed that Car excited state energy decreased with increasing conjugation. Similarly, fluorescence spectra showed that the B850 BChl emission peak had an increasing red shift from LH2Zeta[->](LH2Neu/LH2Spher)[->]LH2Lyco[->]LH2Spir. In contrast, time-resolved fluorescence and ultrafast transient absorption (fs-TA) revealed similar excited state lifetimes ([~]1 ns) for all complexes except LH2Spir ([~]0.7 ns). From fs-TA analysis, an additional [~]7 ps non-radiative dissipation step from B850 BChl was observed for LH2Zeta. Further, singlet-singlet and singlet-triplet annihilation studies showed a [~]50% average fluorescence lifetime reduction in LH2Zeta at high laser power and high repetition rate, compared to [~]10-15% reductions in LH2Neu/LH2Spher/LH2Lyco and minimal lifetime change in LH2Spir. In LH2Zeta, the fastest decay component (<50 ps) became prominent at high repetition rates, consistent with strong singlet-triplet annihilation. Nanosecond TA measurements revealed long-lived (>40 s) BChl triplet states in LH2Zeta and signs of damage caused by singlet oxygen, whereas other LH2s showed faster triplet quenching ([~]18 ns) by Cars. These findings highlight a key design principle of LH2 complexes: the Car triplet energy must be significantly lower than the BChl triplet energy to efficiently quench BChl triplets that otherwise act as potent "trap states" causing exciton annihilation in laser-based experiments or photo-damage in native membranes.

biophysics↗

VAMP8 function reveals tight linkage between endocytic recycling and endocytosis

Clathrin-mediated endocytosis (CME) is a multistage process that involves the initiation and stabilization of clathrin-coated pits (CCPs) that invaginate and finally detach from the plasma membrane to form clathrin-coated vesicles (CCVs). Given that SNARE proteins are essential for downstream vesicle targeting and fusion events, their recruitment into nascent CCVs has been suggested to be a prerequisite for CME progression. However, which and how SNARE proteins regulate CME remains to be explored. Here, we showed that siRNA-mediated knockdown of the R-SNARE, VAMP8 impairs CCP initiation, stabilization and invagination and strongly inhibits CME. Mechanistically, recruitment of VAMP8 to CCVs is not required for CME. Instead, depletion of VAMP8 inhibits recycling of endocytic cargoes and as exemplified here by transferrin receptor, skews their trafficking toward lysosomal degradation. VAMP8 depletion therefore indirectly impairs CCV formation and inhibits CME by depleting endocytic cargo. Overall, our study provides new insights into the crosstalk between endocytosis and endocytic recycling of CME cargo and demonstrates the critical role for cargo recruitment in stabilizing nascent CCPs to regulate CME. Significance StatementWe demonstrate that VAMP8 depletion inhibits recycling of endocytic cargo and reroutes transferrin receptors toward lysosomal degradation, thereby impairing endocytic vesicle formation and inhibiting clathrin-mediated endocytosis. Thus, the work uncovers a critical link between endocytic recycling and endocytosis, highlighting the importance of recycling pathways in maintaining membrane dynamics. However, the recruitment of VAMP8 into nascent clathrin-coated pits by CALM is not required for CME. While SNARE recruitment is essential for formation of COPI and COPII vesicles, our findings suggest that this requirement is not generalizable to endocytic CCVs.

cell biology↗

Dynamic competition between bottom-up saliency and top-down goals in early visual cortex

Task-irrelevant yet salient stimuli can elicit automatic, bottom-up attentional capture and compete with top-down, goal-directed processes for neural representation. However, the temporal dynamics underlying this competition, and how they influence early visual processing, remain poorly understood. Here, we combined electroencephalography (EEG) with Rapid Invisible Frequency Tagging (RIFT) to non-invasively and simultaneously track early visual cortex responses to target and distractor. Both target and distractor evoked stronger initial RIFT responses than nontargets, reflecting top-down and bottom-up attentional effects on early visual processing. Importantly, the presence of a distractor attenuated the initial RIFT response to the target, reflecting competition during the initial stages of visual processing and predicting subsequent behavioral performance. RIFT responses to the distractor eventually even decreased below responses to the target and nontarget, representing active suppression of task-irrelevant but salient stimuli. We show that the dynamic interplay between top-down control and bottom-up saliency directly impacts early visual responses, thereby illuminating a complete timeline of attentional competition in visual cortex.

neuroscience↗

Global diversity of integrating conjugative elements (ICEs) in Helicobacter pylori and their influence on genome architecture

Integrating conjugative elements (ICEs) are mobile genetic elements conferring a wide range of beneficial functions upon their bacterial hosts. Generally, they can be activated from their integrated states to undergo horizontal gene transfer via conjugation. In the case of the human gastric pathogen Helicobacter pylori, a paradigm for extensive genetic diversity, highly efficient natural transformation and recombination processes may superimpose canonical transfer of its two ICEs termed ICEHptfs3 and ICEHptfs4, and thus shape their composition substantially. Here, as a part of the Helicobacter pylori Genome Project (HpGP) initiative, we have analyzed high-quality genome sequences from 1011 clinical strains with respect to their ICE content and variability. We show that both elements are highly prevalent in all H. pylori populations, but have a strong tendency for gene erosion. ICE sequence variations reflect the population structure and show a clear signature of increased horizontal transfer. A detailed map of ICE integration sites revealed local preferences, but also how recombination processes result in hybrid elements or genome rearrangements. Population-specific differences in ICE cargo genes might reflect distinct requirements in the biological functions provided by these mobile elements.

microbiology↗

Plasticity and adaptation to high light intensity amplify the advantage of amphistomatous leaves

The presence of stomata on both leaf surfaces (amphistomy) increases photosynthesis by reducing the distance for CO2 diffusion between stomata and chloroplasts. Paradoxically, most leaves are hypos-tomatous (stomata on lower surface), despite the photosynthetic advantage of amphistomy. Across 29 diverse populations of "wild tomatoes", leaves developed under high light intensity benefit more from amphistomy in terms of CO2 assimilated for a given stomatal conductance than plants developed under low light. Furthermore, populations native to open habitats benefit more from amphistomy than those from more closed habitats. Thus, plasticity and adaptation together may explain why amphistomatous leaves are prevalent in sunny, open habitats, including many crops. Contrary to common assumptions, amphistomy can save water because hypostomatous leaves evaporate 10-65% more to achieve the same photosynthetic rate.

plant biology↗

A prognostic signature for lung adenocarcinoma in people who have never smoked

Knowledge of tumor cell dynamics can inform prognosis and treatment yet is largely lacking for lung adenocarcinoma in people who have never smoked (NS-LUAD). With RNA-seq data from 684 NS-LUAD and validation in an independent dataset, we identified three subtypes with distinct phenotypic traits and cell compositions. Additional genomic and histological data further characterized the subtypes. Steady, marked by low proliferation, high alveolar cell fraction, moderate-to-well differentiation, and fewer driver genes alterations, is linked to prolonged survival and low immune evasion. Proliferative shows high proliferation markers, TP53 mutations, and gene fusions. Chaotic, with high epithelial-to-mesenchymal transition markers, has the worst prognosis even within stage I tumors. Lacking known molecular or histological characteristics, this aggressive subtype is solely identified by transcriptomic data. A 60-gene signature recapitulates the overall classification and strongly predicts survival even within subgroups based on tumor stage or known genomic features, emphasizing its potential for improving NS-LUAD prognostication in clinical settings. SignificanceThe transcriptome of 684 lung adenocarcinomas in people who have never smoked (NS-LUAD) identifies three subtypes with different cellular dynamics, and genomic and morphologic features. A 60-gene signature accurately stratifies subjects for mortality risk, even in stage I, offering a clinically applicable tool for treatment decision making in NS-LUAD patients.

genomics↗

Novel Predictive Spatial Biomarker in Non-Small Cell Lung Carcinoma: The Diversity of Niches Unlocking Treatment Sensitivity (DONUTS)

Probabilistic spatial modelling techniques developed on large-scale tumor-immune Atlases ([~]35M individually mapped cells; 50,000 high power fields) were used to characterize predictive features of treatment-responsive lung cancer. We identified CD8+FoxP3+ cell density as a robust pre-treatment biomarker for outcomes across disease stages and therapy types. In parallel, single-cell RNAseq studies of CD8+FoxP3+ T-cells revealed an activated, early effector phenotype, substantiating an anti-tumor role, and contrasting with CD4+FoxP3+ T-regulatory cells. A spatial biomarker was developed using an empirical probabilistic model to define the immediate cell neighbors or niche surrounding CD8+FoxP3+ cells and proximity to the tumor-stromal boundary. The resultant Diversity of Niches Unlocking Treatment Sensitivity (DONUTS) are more prevalent than the CD8+FoxP3+ cells themselves, mitigating sampling error in small biopsies. Further, the DONUTS only require four markers, are additive to PD-L1, and associate with tertiary lymphoid structure counts. Taken together, the DONUTS represent a next-generation predictive biomarker poised for clinical implementation. HIGHLIGHTSO_LILarge-scale tumor-immune Atlases drive robust computational biomarker development C_LIO_LICD8+FoxP3+ cells are anti-tumor T-cells and predict response to therapy C_LIO_LIThe niches or spatial donuts around CD8+FoxP3+ cells boost biomarker performance C_LIO_LICD8+FoxP3+ donuts are hallmarks of a larger immune organization that includes TLS C_LI

pathology↗

EGFR-targeted antisense oligonucleotides modified with boron clusters offer an innovative approach to cancer chemo-radiotherapy

Suppression of cancer-associated EGFR expression by antisense oligonucleotides is an attractive strategy to augment the efficacy of radiotherapy in cancer treatment. Boron clusters act as selective ligands for the epidermal growth factor receptor (EGFR) and provide an innovative platform for the delivery of naked boron cluster-conjugated therapeutic nucleic acids to cancer cells. Here, we demonstrate that the novel inhibitor B-ASOLNA-CHOL can also enhance efficient and cancer cell-selective uptake via the low-density lipoprotein receptor (LDLR). This conjugate exhibit strong cytotoxic effects on skin and liver cancer cells in combination with BNCT or XRT. We confirmed that intratumoral injections of B-ASOLNA-CHOL combined with local XRT significantly reduced tumor size and EGFR expression in human A431 xenografts implanted in immunodeficient mice. Our findings suggest that B-ASO-CHOL containing a CpG ODN motif exhibits immune adjuvant properties. The results underscore the potential of B-ASOLNA-CHOL technology for therapeutic applications in radiation immuno-oncology. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=119 SRC="FIGDIR/small/668562v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@a275edorg.highwire.dtl.DTLVardef@1ec2c5eorg.highwire.dtl.DTLVardef@54fc6aorg.highwire.dtl.DTLVardef@187bd60_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO C_FIG

biochemistry↗

Serotonin shapes the temporal window for associative fear learning

Fear learning is a critical adaptive mechanism that enables the association of an environmental cue (the conditioned stimulus, CS) with a potential threat (the unconditioned stimulus, US), even when these events are temporally discontiguous. When associations are instead formed between unrelated cues and threats, the maladaptive learning process can give rise to neurological disorders. Therefore, maintaining accurate temporal boundaries for forming such associations is crucial for distinguishing real threats from irrelevant stimuli. Despite its importance, the mechanisms defining this precise time window remain poorly understood. Here, we report that serotonin plays a crucial role in modulating the associable interval in trace fear conditioning. Specifically, we show that serotonergic projections from the dorsal raphe nuclei (DRN) to the CA1 region of the ventral hippocampus (vCA1) dynamically regulate the association of discontiguous CS and US. Mechanistically, we demonstrate that sustained serotonin release in the vCA1 maintains the ensemble activity of 5-HT2C receptor-expressing pyramidal neurons, facilitating the association between temporally separated events. In contrast, when the trace interval exceeds the associable window, transient serotonin release fails to drive vCA1 neuronal ensemble activity, thus preventing maladaptive learning. These findings highlight a key role for serotonin in regulating the temporal precision of fear learning and reveal the DRN-vCA1 serotonergic pathway as a potential therapeutic target for related disorders.

neuroscience↗