Biology subjects

Warren, S.

Publications and source records attributed to Warren, S..

12 recordsLinked to original sources

bioRxiv2026

Histone H3K9 Methyltransferases Regulate Cortical Growth by Coordinating Heterochromatin Formation and Neural Progenitor Dynamics

DNA packaging into heterochromatin is a fundamental mechanism of transcriptional silencing. However, how heterochromatin regulates neurogenesis in the developing cerebral cortex remains poorly understood. A defining feature of heterochromatin is trimethylation of histone H3 lysine 9 (H3K9me3), catalyzed by the H3K9 methyltransferases SETDB1, SUV39H1, and SUV39H2. Here, we generate a cortex-specific triple knockout mouse model lacking Setdb1, Suv39h1, and Suv39h2 to interrogate the collective functions of H3K9 methyltransferases and H3K9me3 during corticogenesis. Loss of H3K9 methyltransferases disrupts cell-cycle dynamics and cortical neurogenesis, resulting in microcephaly. We show that H3K9me3 is associated with the silencing of distinct gene families, lineage-inappropriate genes, and transposable elements, and that its loss is accompanied by local chromatin opening and enhanced transcription factor occupancy. Our findings suggest that H3K9me3 regulates neurogenesis in part by silencing the growth-inhibitory gene Cdkn1c in intermediate progenitors. These results underscore the critical role of heterochromatin in the temporal control of neurogenesis.

developmental biology↗

bioRxiv2025

Scalable prediction of symmetric protein complex structures

All life relies on proteins to function, yet accurately modeling protein structures that exceed {approx} 10, 000 amino acids or have higher-order geometries remains difficult. Existing solutions are limited to specific scenarios, require considerable computational resources, or are otherwise unscalable. Consequently, many large, disease-relevant protein complexes in the human proteome, as well as nearly all viruses and numerous other classes, are impractical to model with high fidelity for drug development. To modulate these protein complexes and viruses, structural information is eminently valuable, and often essential. In the last two years, machine learning based-tools that can generate binders to a given target structure with high hit rates have emerged. Combined with high-throughput screening, these technologies can far outpace traditional drug discovery. However, they cannot function well without accurate models of their target structures. Thus, to unlock the full power of AI-driven drug discovery, a scalable method must be developed to predict large protein complex structures. To overcome this bottleneck, we introduce Plica-1, a physics-based method to rapidly and accurately predict the structure of arbitrarily large, symmetric protein complexes. Validated across 4 major symmetry classes (icosahedral, tetrahedral, octahedral, and cyclic), the method consistently achieves near-experimental levels of accuracy, i.e., RMSD < 5[A]. In test cases, the method runs in < 5 minutes on consumer hardware, 103-105 times faster than the closest comparable software. The largest structure currently built, at {approx}40,000 amino acids, is > 8 times the limit of existing machine learning methods. The results demonstrate that protein complexes can be modeled at significantly improved speeds and scales, making Plica-1 a promising tool for protein engineering and drug development.

bioengineering↗

bioRxiv2024

A PRDM16-CtBP1/2 Complex Interacts with HDAC1/2 to Regulate Transcriptional Programs of Neurogenesis and Guide Cortical Neuron Migration

Chromatin regulation of transcriptional enhancers plays a central role in cell fate specification and differentiation. However, how the coordinated activity of transcription factors and chromatin-modifying enzymes regulates enhancers in neural stem cells (NSCs) and dictates subsequent stages of neuronal differentiation and migration is not well understood. The histone methyltransferase PRDM16 is expressed in NSCs of the developing mouse and human cerebral cortex and is essential for determining the position of upper-layer cortical neurons. Here, we report that PRDM16 interacts with C-terminal binding protein 1 (CtBP1) and CtBP2 to control the transcriptional programs of cortical neurogenesis and regulate upper-layer neuron migration. PRDM16 and CtBP1/2 co-regulate enhancers by interacting with histone deacetylase 1 (HDAC1) and HDAC2, and lysine-specific demethylase 1 (LSD1). In addition, our results suggest that the CCCTC-binding factor CTCF plays a key role in recruiting CtBP1/2 to cortical enhancers. These findings underscore that reduced interactions between PRDM16 and ubiquitous chromatin regulators may contribute to neurodevelopmental deficits in patients with PRDM16 haploinsufficiency.

developmental biology↗

bioRxiv2024

Computational Modeling of Proactive, Reactive, and Attentional Dynamics in Cognitive Control

We developed a novel Proactive Reactive and Attentional Dynamics (PRAD) computational model designed to dissect the latent mechanisms of inhibitory control in human cognition. Leveraging data from over 7,500 participants in the NIH Adolescent Brain Cognitive Development study, we demonstrate that PRAD surpasses traditional models by integrating proactive, reactive, and attentional components of inhibitory control. Employing a hierarchical Bayesian framework, PRAD offers a granular view of the dynamics underpinning action execution and inhibition, provides debiased estimates of stop-signal reaction times, and elucidates individual and temporal variability in cognitive control processes. Our findings reveal significant intra-individual variability, challenging conventional assumptions of random variability across trials. By addressing nonergodicity and systematically accounting for the multicomponential nature of cognitive control, PRAD advances our understanding of the cognitive mechanisms driving individual differences in cognitive control and provides a sophisticated computational framework for dissecting dynamic cognitive processes across diverse populations. Our integrative approach significantly advances psychological theory about the multiple neurocognitive processes underlying cognitive control. We also demonstrate the relevance of our theoretical and modeling framework to understand the cognitive, neural, clinical, and exposomic factors related to cognitive control.

neuroscience↗

bioRxiv2024

The Impact of a Natural Ingredients based Intervention Targeting the Nine Hallmarks of Aging on DNA methylation

Aging interventions have progressed in recent years due to the growing curiosity about how lifestyle impacts longevity. This study assessed the effects of SRW Laboratories Cel System nutraceutical range on epigenetic methylation patterns, inflammation, physical performance, body composition, and epigenetic biomarkers of aging. A 1-year study was conducted with 51 individuals, collecting data at baseline, 3 months, 6 months, and 12 months. Participants were encouraged to walk 10 minutes and practice 5 minutes of mindfulness daily. Significant improvements in muscle strength, body function, and body composition metrics were observed. Epigenetic clock analysis showed a decrease in biological age with significant reductions in stem cell division rates. Immune cell subset analysis indicated significant changes, with increases in eosinophils and CD8T cells and decreases in B memory, CD4T memory, and T-regulatory cells. Predicted epigenetic biomarker proxies (EBPs) showed significant changes in retinol/TTHY, a regulator of cell growth, proliferation, and differentiation, and deoxycholic acid glucuronide levels, a metabolite of deoxycholic acid generated in the liver. Gene ontology analysis revealed significant CpG methylation changes in genes involved in critical biological processes related to aging, such as oxidative stress-induced premature senescence, pyrimidine deoxyribonucleotide metabolic process, TRAIL binding, hyaluronan biosynthetic process, neurotransmitter loading into synaptic vesicles, pore complex assembly, collagen biosynthetic process, protein phosphatase 2A binding activity, and activation of transcription factor binding. Our findings suggest that the Cel System supplement range may effectively reduce biological age and improve health metrics, warranting further investigation into its mechanistic pathways and long-term efficacy.

genomics↗

bioRxiv2024

Reduced temporal and spatial stability of neural activity patterns predict cognitive control deficits in children with ADHD

This study explores the neural underpinnings of cognitive control deficits in ADHD, focusing on overlooked aspects of trial-level variability of neural coding. We employed a novel computational approach to neural decoding on a single-trial basis alongside a cued stop-signal task which allowed us to distinctly probe both proactive and reactive cognitive control. Typically developing (TD) children exhibited stable neural response patterns for efficient proactive and reactive dual control mechanisms. However, neural coding was compromised in children with ADHD. Children with ADHD showed increased temporal variability and diminished spatial stability in neural responses in salience and frontal-parietal network regions, indicating disrupted neural coding during both proactive and reactive control. Moreover, this variability correlated with fluctuating task performance and with more severe symptoms of ADHD. These findings underscore the significance of modeling single-trial variability and representational similarity in understanding distinct components of cognitive control in ADHD, highlighting new perspectives on neurocognitive dysfunction in psychiatric disorders.

neuroscience↗

bioRxiv2024

A Vector System Encoding Histone H3 Mutants Facilitates Manipulations of the Neuronal Epigenome

The differentiation of developmental cell lineages is associated with genome-wide modifications in histone H3 methylation. However, the causal role of histone H3 methylation in transcriptional regulation and cell differentiation has been difficult to test in mammals. The experimental overexpression of histone H3 mutants carrying lysine-to-methionine (K-to-M) substitutions has emerged as an alternative tool for inhibiting the endogenous levels of histone H3 methylation at specific lysine residues. Here, we leverage the use of histone K-to-M mutants by creating Enhanced Episomal Vectors that enable the simultaneous depletion of multiple levels of histone H3 lysine 4 (H3K4) or lysine 9 (H3K9) methylation in projection neurons of the mouse cerebral cortex. Our approach also facilitates the simultaneous depletion of H3K9 and H3K27 trimethylation (H3K9me3 and H3K27me3, respectively) in cortical neurons. In addition, we report a tamoxifen-inducible Cre-FLEX system that allows the activation of mutant histones at specific developmental time points or in the adult cortex, leading to the depletion of specific histone marks. The tools presented here can be implemented in other experimental systems, such as human in vitro models, to test the combinatorial role of histone methylations in developmental fate decisions and the maintenance of cell identity.

neuroscience↗

bioRxiv2022

A single-nucleus and spatial transcriptomic atlas of the COVID-19 liver reveals topological, functional, and regenerative organ disruption in patients

The molecular underpinnings of organ dysfunction in acute COVID-19 and its potential long-term sequelae are under intense investigation. To shed light on these in the context of liver function, we performed single-nucleus RNA-seq and spatial transcriptomic profiling of livers from 17 COVID-19 decedents. We identified hepatocytes positive for SARS-CoV-2 RNA with an expression phenotype resembling infected lung epithelial cells. Integrated analysis and comparisons with healthy controls revealed extensive changes in the cellular composition and expression states in COVID-19 liver, reflecting hepatocellular injury, ductular reaction, pathologic vascular expansion, and fibrogenesis. We also observed Kupffer cell proliferation and erythrocyte progenitors for the first time in a human liver single-cell atlas, resembling similar responses in liver injury in mice and in sepsis, respectively. Despite the absence of a clinical acute liver injury phenotype, endothelial cell composition was dramatically impacted in COVID-19, concomitantly with extensive alterations and profibrogenic activation of reactive cholangiocytes and mesenchymal cells. Our atlas provides novel insights into liver physiology and pathology in COVID-19 and forms a foundational resource for its investigation and understanding.

genomics↗

bioRxiv2021

Fragile X syndrome patient-derived neurons developing in the mouse brain show FMR1 -dependent phenotypes

Abnormal neuronal development in Fragile X syndrome (FXS) is poorly understood. Data on FXS patients remain scarce and FXS animal models have failed to yield successful therapies. In vitro models do not fully recapitulate the morphology and function of human neurons. Here, we co-injected neural precursor cells (NPCs) from FXS patient-derived and corrected isogenic control induced pluripotent stem cells into the brain of neonatal immune-deprived mice. The transplanted cells populated the brain and a proportion differentiated into neurons and glial cells. Single-cell RNA sequencing of transplanted cells revealed upregulated excitatory synaptic transmission and neuronal differentiation pathways in FXS neurons. Immunofluorescence analyses showed accelerated maturation of FXS neurons after an initial delay. Additionally, increased percentages of Arc- and Egr1-positive FXS neurons and wider dendritic protrusions of mature FXS striatal medium spiny neurons pointed to an increase in synaptic activity and synaptic strength as compared to control. This transplantation approach provides new insights into the alterations of neuronal development in FXS by facilitating physiological development of cells in a 3D context, and could be used to test new therapeutic compounds correcting neuronal development defects in FXS.

neuroscience↗

bioRxiv2021

Systemic Tissue and Cellular Disruption from SARS-CoV-2 Infection revealed in COVID-19 Autopsies and Spatial Omics Tissue Maps

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus has infected over 115 million people and caused over 2.5 million deaths worldwide. Yet, the molecular mechanisms underlying the clinical manifestations of COVID-19, as well as what distinguishes them from common seasonal influenza virus and other lung injury states such as Acute Respiratory Distress Syndrome (ARDS), remains poorly understood. To address these challenges, we combined transcriptional profiling of 646 clinical nasopharyngeal swabs and 39 patient autopsy tissues, matched with spatial protein and expression profiling (GeoMx) across 357 tissue sections. These results define both body-wide and tissue-specific (heart, liver, lung, kidney, and lymph nodes) damage wrought by the SARS-CoV-2 infection, evident as a function of varying viral load (high vs. low) during the course of infection and specific, transcriptional dysregulation in splicing isoforms, T cell receptor expression, and cellular expression states. In particular, cardiac and lung tissues revealed the largest degree of splicing isoform switching and cell expression state loss. Overall, these findings reveal a systemic disruption of cellular and transcriptional pathways from COVID-19 across all tissues, which can inform subsequent studies to combat the mortality of COVID-19, as well to better understand the molecular dynamics of lethal SARS-CoV-2 infection and other viruses.

microbiology↗

bioRxiv2019

Partial FMRP expression is sufficient to normalize neuronal hyperactivity in Fragile X neurons

Fragile X Syndrome (FXS) is the most common genetic form of intellectual disability caused by a CGG repeat expansion in the 5-UTR of the Fragile X mental retardation gene FMR1, triggering epigenetic silencing and the subsequent absence of the protein, FMRP. Reactivation of FMR1 represents an attractive therapeutic strategy targeting the genetic root cause of FXS. However, largely missing in the FXS field is an understanding of how much FMR1 reactivation is required to rescue FMRP-dependent mutant phenotypes. Here, we utilize FXS patient derived excitatory neurons to model FXS in vitro and confirm that the absence of FMRP leads to neuronal hyperactivity. We further determined the levels of FMRP and the percentage of FMRP positive cells necessary to correct this phenotype utilizing a mixed and mosaic neuronal culture system and a combination of CRISPR, antisense and expression technologies to titrate FMRP in FXS and WT neurons. Our data demonstrate that restoration of greater than 5% of overall FMRP expression levels or greater than 20% FMRP expressing neurons in a mosaic pattern is sufficient to normalize a FMRP-dependent, hyperactive phenotype in FXS iPSC-derived neurons.\n\nHighlightsO_LICRISPR gene editing to generate FMRP KO and CGG-deleted isogenic iPSCs\nC_LIO_LIMEA as an approach to identify FMR1 dependent phenotype in NGN2 neurons derived from FXS and FMRP KO iPSCs\nC_LIO_LICell mixing paradigm as mosaicism in a dish to rescue phenotype\nC_LIO_LIMinimal level of FMRP determined by FMR1 mRNA and targeted demethylation of CGG repeats to correct the hyperactive phenotype in FXS neurons\nC_LIO_LIASO titration-validated partial expression of FMRP is sufficient to normalize increased neuronal activity\nC_LI

neuroscience↗

bioRxiv2019

High multiplex, digital spatial profiling of proteins and RNA in fixed tissue using genomic detection methods

We have developed Digital Spatial Profiling (DSP), a non-destructive method for high-plex spatial profiling of proteins and RNA, using oligonucleotide detection technologies with unlimited multiplexing capability. The key breakthroughs underlying DSP are threefold: (1) multiplexed readout of proteins/RNA using oligo-tags; (2) oligo-tags attached to affinity reagents (antibodies/RNA probes) through a photocleavable (PC) linker; (3) photocleaving light projected onto the tissue sample to release PC-oligos in any spatial pattern. Here we show precise analyte reproducibility, validation, and cellular resolution using DSP. We also demonstrate biological proof-of-concept using lymphoid, colorectal tumor, and autoimmune tissue as models to profile immune cell populations, stroma, and cancer cells to identify factors specific for the diseased microenvironment. DSP utilizes the unlimited multiplexing capability of modern genomic approaches, while simultaneously providing spatial context of protein and RNA to examine biological questions based on analyte location and distribution.

pathology↗