Biology subjects

Zhou, H.

Publications and source records attributed to Zhou, H..

At least 145 records · Page 8Linked to original sources

bioRxiv2025

MsyB-HU Interaction Modulates a Two-Tiered Bacterial Stress Response by Regulating DNA Supercoiling

Bacteria respond to stressful conditions through multiple pathways, including changes in gene expression patterns and mutations for adaptation. DNA supercoiling is a fundamental regulatory principle of bacterial gene expression, controlled antagonistically by DNA gyrase and topoisomerase I. Nucleoid-associated proteins, such as HU, also regulate supercoiling through interactions with DNA. Here, we identify Escherichia coli protein MsyB as a HU inhibitor and a {beta}-clamp binder. MsyB is fine-tuned under various stressful conditions, where it modulates the population of DNA-bound HU by forming a HU-MsyB complex. Consequently, the balance between DNA-bound HU and MsyB-bound HU adjusts the DNA supercoiling state, thereby influencing transcription for adaptation. Additionally, under prolonged starvation during the stationary phase, sustained high level of MsyB increases DNA exposure to damaging factors, acting as a damage inducer. The HU/MsyB/{beta}-clamp interaction suggests a model in which MsyB coordinates with HU and the {beta}-clamp to facilitate damage acquisition and error-prone DNA repair. Thus, MsyB-dependent supercoiling regulation represents a novel two-tiered bacterial stress response mechanism in gene expression and adaptive mutation. Our findings reveal a previously unrecognized regulatory mechanism of bacterial supercoiling, positioning HU as a promising antibiotic target.

microbiology↗

bioRxiv2025

Lymph nodes link sex-biased immune aging to compromised antigen recognition

The numerical abundance of diverse naive CD8 T cell clones is essential to provide broad protection against infection and cancer. Here, we uncover a sex-biased mechanism of immune aging in which an early, male-biased depletion of naive CD8 T cells driven by accelerated, antigen-agnostic differentiation into virtual memory cells is combined with age-related thymic involution that limits naive CD8 T cell replenishment. These mechanisms lead to contraction of lymph nodes and reduced local naive T cell clone availability, limiting cancer antigen recognition capacity. Therapeutic thymus regeneration via androgen ablation repopulates naive CD8 T cells in lymph nodes, which reinvigorates cancer-specific T cell responses and enhances responsiveness to immune checkpoint blockade. These findings reveal the crucial impact of sex and age on naive T cell clone abundance in lymph nodes and suggest strategies to restore immune competence in middle-aged males.

immunology↗

bioRxiv2025

Circulating Exosomal PCNA: A Biomarker for Early and Pan-Cancer Detection

Detecting multiple cancers with a single, non-invasive liquid biopsy test remains a challenge, as no universally shared cancer biomarker with clinical significance has been identified in bodily fluids. In this study, we identified proliferating cell nuclear antigen (PCNA), a well-established pathological cancer biomarker in tissue biopsies, as being secreted into peripheral bodily fluids within exosomes. Our research demonstrated that cultured cancer cells continuously release large quantities of exosomal PCNA into their surrounding media. Furthermore, we confirmed its presence in human serum. Most importantly, cancer patients exhibited significantly higher levels of exosomal PCNA in their sera compared to healthy individuals. To assess its diagnostic potential, we evaluated the sensitivity and specificity of exosomal PCNA in a cohort of cancer patients and healthy controls. Receiver operating characteristic (ROC) analysis revealed a sensitivity of 77.2% and a specificity of 94.4%. These findings establish exosomal PCNA in peripheral bodily fluids as a promising universal biomarker for the early detection, diagnosis, and monitoring of multiple cancers through liquid biopsy.

cancer biology↗

bioRxiv2025

How Does Sampling Affect the AI Prediction Accuracy of Peptides' Physicochemical Properties?

Accurate AI prediction of peptide physicochemical properties is essential for advancing peptide-based biomedicine, biotechnology, and bioengineering. However, the performance of predictive AI models is significantly affected by the representativeness of the training data, which depends on the sample size and sampling methods employed. This study addresses the challenge of determining the optimal sample size and sampling methods to enhance the predictive accuracy and generalization capacity of AI models for estimating the aggregation propensity, hydrophilicity, and isoelectric point of tetrapeptides. Four sampling methods were evaluated: Latin Hypercube Sampling (LHS), Uniform Design Sampling (UDS), Simple Random Sampling (SRS), and Probability-Proportional-to-Size Sampling (PPS), across sample sizes ranging from 100 to 20,000. A sample size of approximately 12,000 (7.5% of the total tetrapeptide dataset) marks a key threshold for stable and consistent model performance. This study provides valuable insights into the interplay between sample size, sampling strategies, and model performance, offering a foundational framework for optimizing data collection and AI model training for the prediction of peptides physicochemical properties, especially for prediction in the complete sequence space of longer peptides with more than four amino acids.

bioinformatics↗

bioRxiv2025

Fluorescence Lifetime Imaging Microscopy (FLIM) visualizes internalization and biological impact of nanoplastics in live intestinal organoids

The increasing micro- and nanoplastic (MNP) pollution poses significant risks to human and animal health, yet the mechanisms of their accumulation and effects on absorptive tissues such as the gastrointestinal tract remain poorly understood. Addressing these knowledge gaps requires tractable models coupled to dynamic live cell imaging methods, to enable multi-parameter analysis at single cell resolution. Here we report a new method combining adult stem cell-derived small intestinal organoid cultures with multi-parameter live Fluorescence Lifetime Imaging Microscopy (FLIM) to study MNP interactions with gut epithelium. To facilitate this, we optimized live imaging of porcine and mouse small intestinal organoids with an apical-out topology. Subsequently, we produced a set of pristine MNPs based on PMMA and PS (<200 nm, doped with deep-red fluorescent dye) exhibiting different surface charges, and evaluated their interaction with organoids displaying controlled epithelial polarity. We found that nanoparticles differently interacted with apical and basal membranes of the organoids and even showed a species-specific pattern of cellular uptake. Using a phasor-FLIM approach, we demonstrate better sensitivity of FLIM over conventional intensity-based microscopy. The fluorescence lifetime barcoding enabled distinguishing different types of MNP and their interaction sites within organoids. Finally, we studied short (1 day)- and long (3 days)-term exposure effects of PMMA and PS-based MNPs on mitochondrial function, total energy budget and epithelial inflammation and found that even pristine MNPs could disrupt chemokine production and mitochondrial membrane potential in intestinal epithelial cells. The presented FLIM approach will advance the study of MNP toxicity, their biological impacts on gastrointestinal tissue and help tracing other types of fluorescent nanoparticles in live organoid and 3D ex vivo systems.

pharmacology and toxicology↗

bioRxiv2025

Depicting pathogenesis of osteomyelitis by single cell RNA-sequencing and an involvement of Morrbid in the autoinflammatory disease

Autoinflammatory diseases (AIDs) are defined as abnormal activation of the innate immune system leading to spontaneous and uncontrolled inflammation. The AIDs affect bone tissue and lead to chronic recurrent multifocal osteomyelitis (CRMO). However, the etiology and treatment of CRMO remain elusive. A mouse strain, Pstpip2cmo/cmo (cmo: chronic multifocal osteomyelitis), exhibits phenotypic characteristics similar to human CRMO. Morrbid is a long non-coding RNA gene and has been indicated in leukemogenesis in our previous studies. In this study, we demonstrated that Morrbid and Pstpip2 are co-expressed in mature myeloid cells and hypothesized a role of Morrbid in osteomyelitis. The Pstpip2-/- mice have the same phenotype as Pstpip2cmo/cmo, mimicking CRMO, while loss of Morrbid in Pstpip2-/-mice significantly inhibited the initiation and progression of CRMO symptoms, as well as the dysregulated activation of myeloid cells and the excessive release of inflammatory cytokines. Furthermore, single-cell RNA-sequencing (scRNA-seq) analysis from the Pstpip2-/- mice and the compound mutant mice supports that reduction of osteoclasts and inflammatory cells caused by Morrbid loss. The study systematically profiles the etiology of CRMO by scRNA-seq and warrants that inhibiting the lifespan of inflammatory myeloid cells by targeting Morrbid is an effective therapeutic strategy for osteomyelitis. HighlightsO_LIWe generated a frameshift mutant mouse strain Pstpip2-/-, which have a classic CRMO-like phenotype as same as Pstpip2cmo/cmo and could be used for testing various anti-inflammation perturbations. C_LIO_LILoss of Morrbid significantly inhibited the autoinflammatory symptoms in Pstpip2-/- mice, suggesting that Morrbid is a novel target for mitigating CRMO. C_LIO_LIscRNA-seq analysis of the affected bone marrow cells in Pstpip2-/-revealed the abnormalities of osteoclasts (OC), neutrophils (NE) and granulocyte macrophage progenitors (GMP) in both their fractions and inflammatory activities. C_LIO_LIUpon loss of Morrbid, we observed reduced composition and proliferation of OC and decreased activity of Nfkb2 and Rela in the compound mutants. C_LI

immunology↗

bioRxiv2025

Lipid nanoparticle delivery of siRNA to dorsal root ganglion neurons to treat pain

Sensory neurons within the dorsal root ganglion (DRG) are the primary trigger of pain, relaying activity about noxious stimuli from the periphery to the central nervous system; however, targeting DRG neurons for pain management has remained a clinical challenge. Here, we demonstrate the use of lipid nanoparticles (LNPs) for effective intrathecal delivery of small interfering RNA (siRNA) to DRG neurons, achieving potent silencing of the transient receptor potential vanilloid 1 (TRPV1) ion channel that is predominantly expressed in nociceptor sensory neurons. This leads to a reversible interruption of heat-, capsaicin-, and inflammation-induced nociceptive conduction, as observed by behavioral outputs. Our work provides a proof-of-concept for intrathecal siRNA therapy as a novel and selective analgesic modality.

neuroscience↗

bioRxiv2025

Multi-scale structure of chromatin condensates rationalizes phase separation and material properties

Biomolecular condensates, compartments that concentrate molecules without surrounding membranes, are integral to numerous cellular processes. The structure and interaction networks of molecules within condensates remain poorly understood. Using cryo-electron tomography and molecular dynamics simulations we elucidated the structure of phase separated chromatin condensates across scales, from individual amino acids to network architecture. We found that internucleosomal DNA linker length controls nucleosome arrangement and histone tail interactions, shaping the structure of individual chromatin molecules both within and outside condensates. This structural modulation determines the balance between intra- and intermolecular interactions, which in turn governs the molecular network, thermodynamic stability, and material properties of chromatin condensates. Mammalian nuclei contain dense clusters of nucleosomes whose non-random organization is mirrored by the reconstituted condensates. Our work explains how the structure of individual chromatin molecules ultimately determines physical properties of chromatin condensates, with implications for cellular chromatin organization.

biophysics↗

bioRxiv2025

Epidermal Cell Dynamics Regulates Rice Lamina Joint Morphogenesis and Leaf Angle Formation through OsZHD1 and OsZHD2 Regulation

The lamina joint is a critical determinant of leaf angle and crop architecture. While epidermal cells play a fundamental role in organ morphogenesis, influencing the overall shape and function of plants, their impact on lamina joint morphology has been largely overlooked. Here, we tracked the cellular dynamics of the rice lamina joint epidermis during leaf angle formation. We found that the asymmetric elongation between the lateral and medial edges, determined by spatial differences in the longitudinal elongation and number of epidermal cells, was a key factor in leaf angle formation. Mutations in the homeobox genes OsZHD1 and OsZHD2 disrupted the growth patterns of epidermal cells in the lamina joint, resulting in a decreased leaf angle. Restoring OsZHD1 expression in the epidermis reverted the reduced leaf angle phenotype of oszhd1 oszhd2, highlighting the importance of epidermis development for lamina joint morphogenesis. Transcriptome data suggested that OsZHD1 and OsZHD2 were involved in auxin synthesis, which modulates leaf angle by inhibiting the growth of lamina joint epidermal cells. This study underscores the significance of epidermal cells in shaping the lamina joint and elucidates the critical role of OsZHD1 and OsZHD2 in regulating epidermal cell behavior and leaf angle formation.

plant biology↗

bioRxiv2025

Variational Autoencoder-based Model Improves Polygenic Prediction in Blood Cell Traits

Genetic prediction of complex traits, enabled by large-scale genomic studies, has created new measures to understand individual genetic predisposition. Polygenic Risk Scores (PRS) offer a way to aggregate information across the genome, enabling personalized risk prediction for complex traits and diseases. However, conventional PRS calculation methods that rely on linear models are limited in their ability to capture complex patterns and interaction effects in high-dimensional genomic data. In this study, we seek to improve the predictive power of PRS through applying advanced deep learning techniques. We show that the Variational AutoEncoder-based model for PRS construction (VAE-PRS) outperforms currently state-of-the-art methods for biobank-level data in 14 out of 16 blood cell traits, while being computationally efficient. Through comprehensive experiments, we found that the VAE-PRS model offers the ability to capture interaction effects in high-dimensional data and shows robust performance across different pre-screened variant sets. Furthermore, VAE-PRS is easily interpretable via assessing the contribution of each individual marker to the final prediction score through the SHapley Additive exPlanations (SHAP) method, providing potential new insights in identifying trait-associated genetic variants. In summary, VAE-PRS presents a novel measure to genetic risk prediction by harnessing the power of deep learning methods, which could further facilitate the development of personalized medicine and genetic research.

bioinformatics↗

bioRxiv2025

A multilamellar organelle for chemosymbiosis in an aplacophoran mollusc adapted to anoxic cold seep sediment

Symbiosis with chemoautotrophic bacteria has evolved in many animal lineages inhabiting reducing habitats such as hydrothermal vents, allowing these holobionts to thrive in dark biospheres1. In certain instances, the symbionts have become intracellular, residing within specialised bacteriocytes2. The integration of microbial symbionts with eukaryotic cells vary across known animals; however, no specialised organelle dedicated to chemosynthesis has been identified yet2. Here, we report a mode of symbiosis where sulphur-oxidising bacteria cultured within spherical multilamellar compartments (~12 m) in the cold-seep aplacophoran mollusc Chaetoderma shenloong. This organelle, which we name dracosphera, is ubiquitous within the hypertrophied and intricately reticulate digestive gland of C. shenloong, which has otherwise lost most of its gut. Given that the symbionts are strictly anaerobic and the host resides in anoxic sediments tens of centimetres below the surface, the dracosphera may serve to minimise oxygen diffusion to the bacteria, akin to mechanisms observed in microbial diazotrophs3 or termite hindguts4, as supported by our genomic and spatial transcriptomic analyses. Hypoxic conditions have been known to induce radical adaptations in meiofauna, exemplified by the acquisition of hydrogenosomes5. Our discovery of similarly exceptional adaptations in C. shenloong provides new insights into the evolution of such organelles also in larger animals.

microbiology↗

bioRxiv2025

Food pairing independently associated with cardiometabolic traits beyond dietary patterns across western and eastern populations

Cardiometabolic health is closely linked to diet. Both specific food choices and dietary indices are commonly used to guide cardiometabolic protection strategies. However, the balance between foods may also significantly impact cardiometabolic health. Here, we explore the balance and imbalance in long-term dietary food intake to quantify food pairing patterns (FPs), providing insights beyond conventional dietary indices and single-food intake frequencies. Using data from our GGMP (n = 6,994) and the NHANES (n = 7,350) cohorts, we observed that long-term food pairing patterns are independent of single food intake frequency and dietary indices. We identified 1,759 and 306 cardiometabolic-related long-term food pairing patterns from two cohorts (FDR < 0.05), respectively. Notably, around 80% of these pairing foods not individually associated with cardiometabolic traits, and food pairing pattern associations with cardiometabolic traits at hyper food group level were consistent across Eastern and Western populations. Besides, mediation analysis revealed that 72.7% of long-term food pairing patterns affected cardiometabolic traits through 31 microbial genera, with Clostridiumsensustricto1 playing a predominant role. Moreover, multi-step mediation analysis found that microbes mediated the impact of long-term food pairing patterns on cardiometabolic traits primarily through their metabolic pathways, such as pyruvate fermentation to propanoate and ergothioneine biosynthesis pathways. Our data suggest that balance between dietary foods is broadly associated with cardiometabolic traits by modulating gut microbial functionalities, in contrast to the lower occurrence when considering individual foods in isolation. These results offer a novel perspective for designing personalized dietary strategies beyond present dietary indices to enhance cardiometabolic health.

microbiology↗

bioRxiv2024

Prediction of Cell States and Key Transcription Factors of the Human Cornea through Integrated Single-Cell Omics Analyses

The cornea, a transparent tissue composed of multiple layers, allows light to enter the eye. Several single-cell RNA-seq analyses have been performed to explore the cell states and to understand the cellular composition of the human cornea. However, the inconsistences in cell state annotations between these studies complicate the application of these findings in corneal studies. To address this, we integrated single-cell RNA-seq data from four published studies and created a human corneal cell state meta-atlas. This meta-atlas was subsequently evaluated in two applications. First, we developed a machine learning pipeline cPredictor, using the human corneal cell state meta-atlas as input, to annotate corneal cell states. We demonstrated the accuracy of cPredictor and its ability to identify novel marker genes and rare cell states in the human cornea. Furthermore, cPredictor revealed the differences of the cell states between pluripotent stem cell-derived corneal organoids and the human cornea. Second, we integrated the single-cell RNA-seq based cell state meta-atlas with chromatin accessibility data, conducting motif-focused and gene regulatory network analyses. These approaches identified distinct transcription factors driving cell states of the human cornea. The novel marker genes and transcription factors were validated by immunohistochemistry. Overall, this study offers a reliable and accessible reference for profiling corneal cell states, which facilitates future research in cornea development, disease and regeneration. Significance statementThis study creates a human corneal cell state meta-atlas that provides a common nomenclature of cells in the human cornea, through integrating multiple single-cell RNA-seq analyses. Using this meta-atlas, we developed a machine learning pipeline, cPredictor, to accurately annotate cell states in corneal studies using single-cell RNA-seq. Additionally, we identified distinct transcription factors driving cell states through integrating the atlas with chromatin accessibility data. This meta-atlas and the computational tool cPredictor enable future research in cornea development, disease, and regeneration.

cell biology↗

bioRxiv2024

Clathrins are involved in the endocytosis of host cytosol in the malaria parasite

In eukaryotic cells, clathrins interact with adaptor protein complexes to regulate key intracellular trafficking events. Specifically, they are associated with the adaptor protein (AP) complex-2 (AP2) to facilitate endocytosis and AP1 to mediate secretion and trafficking between endosome and Golgi. In Plasmodium falciparum, recent studies revealed that the Kelch domain-containing protein 13 and AP2 participate in hemoglobin uptake via cytostomes. However, clathrins appear not to be involved in this process because they primarily associate with AP1. To investigate the roles of clathrins in P. falciparum, we characterized the clathrin heavy chain (PfCHC), the clathrin light chain (PfCLC), and the AP1 {gamma} subunit (PfAP1 {gamma}). Extensive interactome analyses confirmed the major association of clathrins with AP1 components alongside proteins involved in cytostome formation. Live-cell imaging and protein colocalization studies showed that PfCHC, PfCLC, and PfAP1 {gamma} are localized in the parasite cytoplasm, predominantly at the parasite periphery and near the cis-Golgi. Ultrastructural studies using ascorbate peroxidase 2- based electron microscopy confirmed their presence at coated vesicle-like structures at the parasite periphery and, unexpectedly, at the collars of cytostomes. Consistent with these observations, the knockdown of PfCHC led to the formation of abnormally long cytostome tubes and impaired hemoglobin digestion. This study demonstrates that clathrins are essential for proper cytostome formation in P. falciparum, highlighting their critical role in the parasites hemoglobin uptake and digestion processes. IMPORTANCEMalaria is still one of the most severe public health problems worldwide and understanding how malaria parasites obtain hemoglobin from their host cells, red blood cells (RBCs), is critical for identifying targets for antimalarials. In this study, affinity purification revealed that clathrins (PfCHC and PfCLC) were not only mainly associated with AP1 complex but also marginally interacted with proteins that participated in hemoglobin uptake. Localization analysis demonstrated that clathrins and AP1 coated the clusters of vesicles at the parasite periphery and at the neck of the cytostome, an organelle for hemoglobin uptake. Consistently, the knockdown of PfCHC caused the formation of abnormally long cytostome tubes and reduced hemoglobin digestion. Collectively, this study demonstrates that clathrins play a critical role in the parasites hemoglobin uptake.

microbiology↗

bioRxiv2024

Mechanical force regulates the inhibitory function of PD-1

The immune checkpoint molecule, programmed cell death 1 (PD-1), plays a pivotal role in regulating T-cell function. Upon binding to its ligands, PD-L1 or PD-L2, PD-1 suppresses T-cell receptor signaling, thereby preventing T-cell activation, making it a critical target in cancer immunotherapy. Although extensively studied, the molecular mechanism of PD-1s inhibitory function is still not fully understood, especially at the atomic level. Using the biomembrane force probe (BFP), we discovered that interactions between PD-1 and PD-L1/PD-L2 exhibit catch-slip bond behavior under force. At lower forces, catch bonds are observed, transitioning to slip bond as the force increases. Steered molecular dynamics (SMD) simulations revealed a force-induced bond state between PD-1 and its ligands, distinct from the force-free state observed in solved complex structures. Disrupting interactions that stabilize either state weakens the catch bond and diminishes PD-1s inhibitory function. Interestingly, soluble forms of PD-L1 and PD-L2 compete with their surface-bond counterparts, attenuating PD-1s suppression of T-cell activation. This suggests that soluble PD-1 ligands could potentially serve as anti-PD-1 drugs. Tumor growth studies in mice confirmed the anti-cancer activity of soluble PD-L1. Our findings highlight the critical role of mechanical force in PD-1s inhibitory function, suggesting that PD-1 may act as a mechanical sensor in suppressing T-cell activation. These insights indicate that mechanical regulation should be considered when designing PD-1 blocking inhibitors and other PD-1 related cancer immunotherapies. TeaserThis study shows that the interaction between PD-1 and its ligands is force-dependent, and soluble forms of PD-1 ligands can potentially serve as PD-1 blockers in cancer immunotherapy.

biophysics↗

bioRxiv2024

Systems biology-enabled targeting of NF-κB and BCL2 overcomes microenvironment-mediated BH3-mimetic resistance in DLBCL.

In Diffuse Large B-cell Lymphoma (DLBCL), elevated anti-apoptotic BCL2-family proteins (e.g., MCL1, BCL2, BCLXL) and NF-{kappa}B subunits (RelA, RelB, cRel) confer poor prognosis. Heterogeneous expression, regulatory complexity, and redundancy offsetting the inhibition of individual proteins, complicate the assignment of targeted therapy. We combined flow cytometry fingerprinting, immunofluorescence imaging, and computational modeling to identify therapeutic vulnerabilities in DLBCL. The combined workflow predicted selective responses to BCL2 inhibition (venetoclax) and non-canonical NF-{kappa}B inhibition (Amgen16). Within the U2932 cell line we identified distinct resistance mechanisms to BCL2 inhibition in cellular sub-populations recapitulating intratumoral heterogeneity. Co-cultures with CD40L-expressing stromal cells, mimicking the tumor microenvironment (TME), induced resistance to BCL2 and BCLXL targeting BH3-mimetics via cell-type specific upregulation of BCLXL or MCL1. Computational models, validated experimentally, showed that basal NF-{kappa}B activation determined whether CD40 activation drove BH3-mimetic resistance through upregulation of RelB and BCLXL, or cRel and MCL1. High basal NF-{kappa}B activity could be overcome by inhibiting BTK to resensitize cells to BH3-mimetics in CD40L co-culture. Importantly, non-canonical NF-{kappa}B inhibition overcame heterogeneous compensatory BCL2 upregulation, restoring sensitivity to both BCL2- and BCLXL-targeting BH3-mimetics. Combined molecular fingerprinting and computational modelling provides a strategy for the precision use of BH3-mimetics and NF-{kappa}B inhibitors in DLBCL.

cancer biology↗

bioRxiv2024

Human stem cell-derived GABAergic interneuron development reveals early emergence of subtype diversity followed by gradual electrochemical maturation

Medial ganglionic eminence-derived inhibitory GABAergic pallial interneurons (MGE-pINs) are essential regulators of cortical circuits; their dysfunction is associated with numerous neurological disorders. We developed human (h) MGE-pINs from pluripotent stem cells for the treatment of drug-resistant epilepsy. Here, we analyzed xenografted hMGE-pINs over the lifespan of host mice using single nuclei RNA sequencing. Comparative transcriptomics against endogenous human brain datasets revealed that 97% of grafted cells developed into somatostatin (SST) and parvalbumin (PVALB) subtypes, including populations that exhibit selective vulnerability in Alzheimers disease. Transplanted hMGE-pINs demonstrated rapid emergence of subclass features, progressing through distinct transcriptional states sequentially involving neuronal migration, synapse organization, and membrane maturation. We present molecular, electrophysiological, and morphological data that collectively confirm the derivation of diverse bona-fide human SST and PVALB subtypes, providing a high-fidelity model to study human MGE-pIN development and functional maturation as well as a compositional atlas for regenerative cell therapy applications.

neuroscience↗

bioRxiv2024

Quantitative Spatial Analysis of Chromatin Biomolecular Condensates using Cryo-Electron Tomography

Phase separation is an important mechanism to generate certain biomolecular condensates and organize the cell interior. Condensate formation and function remain incompletely understood due to difficulties in visualizing the condensate interior at high resolution. Here we analyzed the structure of biochemically reconstituted chromatin condensates through cryo-electron tomography. We found that traditional blotting methods of sample preparation were inadequate, and high-pressure freezing plus focused ion beam milling was essential to maintain condensate integrity. To identify densely packed molecules within the condensate, we integrated deep learning-based segmentation with novel context-aware template matching. Our approaches were developed on chromatin condensates, and were also effective on condensed regions of in situ native chromatin. Using these methods, we determined the average structure of nucleosomes to 6.1 and 12 [A] resolution in reconstituted and native systems, respectively, and found that nucleosomes form heterogeneous interaction networks in both cases. Our methods should be applicable to diverse biochemically reconstituted biomolecular condensates and to some condensates in cells.

biophysics↗