Biology subjects

Tanwar, V. S.

Publications and source records attributed to Tanwar, V. S..

4 recordsLinked to original sources

bioRxiv2026

Epigenome Alterations and 3D Chromatin Architecture Remodeling in Inflammatory Macrophage Activation under Diabetic Conditions

Aberrant monocyte/macrophage activation in diabetes drives chronic inflammation and complications. While epigenetic mechanisms are implicated, the role of 3D-chromatin reorganization remains unclear. Using integrated multi-Omics, we profiled gene expression and 3D-chromatin architecture in human CD14+ monocyte-differentiated macrophages treated with high glucose + TNF- (HT) mimicking the diabetic milieu. HT induced inflammatory programs resembling those in diabetes, and dynamically altered chromatin accessibility, enhancer-promoter loops, transcriptionally active/inactive (A/B) compartments, and topologically associated domains. Inflammatory genes exhibited increased, whereas cell-cycle and metabolic genes showed reduced chromatin accessibility and enhancer-promoter interactions. These architectural changes facilitated the convergence of lineage-specific and signal-dependent transcription factors at enhancer-promoter loops, forming network hubs orchestrating pro-inflammatory responses. Similar enhancer-promoter interactions were observed in monocytes from individuals with diabetes. Perturbing chromatin interactions via CRISPR-interference targeting HT-induced enhancers suppressed inflammatory gene expression. Results from this first comprehensive enhancer connectome maps in macrophages under diabetic conditions reveal disease-associated rewiring of the 3D epigenome, highlighting epigenetic mechanisms as potential therapeutic targets. TeaserDiabetic conditions rewire 3D chromatin organization and enhancer-promoter interactions in human macrophages, promoting chronic inflammation.

genomics↗

bioRxiv2025

Single-Cell Multimodal Profiling Highlights Persistent Aortic Smooth Muscle Cell Changes in Diabetic Mice Despite Glycemic Control

BackgroundType 2 diabetes (T2D) is associated with accelerated vascular complications like hypertension and atherosclerosis. "Phenotypic switching" of vascular smooth muscle cells (SMC), a major driver of these complications, is enhanced in diabetes. Despite adequate glycemic control, SMC dysfunction can persist due to "metabolic memory" of prior hyperglycemia. However, the mechanisms of hyperglycemic memory associated with persistent SMC dysfunction are unclear. Here, leveraging single-cell (sc) multi-omics, we examined the effect of glucose normalization on transcriptomic and epigenomic changes associated with SMC phenotypic transition in T2D mice. MethodsWe treated T2D db/db mice with the antidiabetic drug dapagliflozin (DAPA) (db/dbDAPA) or vehicle (db/db), and non-diabetic control db/+ mice with vehicle for 6 weeks. Dissected aortas were subjected to scRNA-seq, scATAC-seq, and spatial transcriptomics (Xenium) to determine single-cell changes in gene expression and chromatin accessibility. ResultsDAPA treatment conferred effective glycemic control in db/db mice, with significant reductions in blood glucose/hemoglobin A1c. scRNA and scATAC-seq analysis of aortas identified major cell populations, including SMC, fibroblasts, endothelial and immune cells. SMC were further clustered into 9 subtypes, including contractile and fibromyocyte-like cells. Cell composition analysis revealed decreases in contractile SMC and increases in vascular remodeling associated fibromyocyte-like SMC in db/db versus db/+ mice. Interestingly, DAPA did not reverse diabetes-induced decreases in contractile markers but reversed changes in several fibromyocyte markers in db/db mice. Pseudotime trajectory analysis revealed increased activities of fibromyocyte enriched transcription factors (TFs) during contractile to fibromyocyte transition. Furthermore, increased expression of TFs regulating fibromyocyte phenotype (e.g. Atf4, Bach1, Hand2, Fosl2) in db/db were partially reversed by DAPA, whereas reduced contractile TF (Mef2c) expression was unchanged. Spatial transcriptomics analysis further mapped aortic cell types within intact aortas and confirmed that DAPA reversed alterations in key fibromyocyte but not contractile genes in db/db mouse aortas. ConclusionsPersistent epigenetic changes may contribute to sustained vascular remodeling and dysfunction in T2D. T2D reduced contractile SMC gene expression and related chromatin accessibility and promoted phenotypic transition to fibromyocytes. These changes are only partially reversed by a widely used antidiabetic drug like DAPA, underscoring the need for more effective therapies that target hyperglycemic memory.

biochemistry↗

bioRxiv2019

Nickel induced transcriptional changes persist post exposure through epigenetic reprograming

Nickel is an occupational and environmental toxicant associated with a number of diseases in humans including pulmonary fibrosis, bronchitis and lung and nasal cancers. Our earlier studies showed that the nickel-exposure-induced genome-wide transcriptional changes, which persist even after the termination of exposure may underlie nickel pathogenesis. However, the mechanisms that drive nickel-induced persistent changes to the transcriptome remain elusive. To elucidate the mechanisms that underlie nickel induced long-term transcriptional changes, in this study, we examined the transcriptome and the epigenome of human lung epithelial cells during nickel exposure and after the termination of exposure. We identified two categories of persistently differentially expressed genes based on the timing of expression changes: i) the genes that were differentially expressed during nickel exposure; and ii) the genes that were differentially expressed only after the termination of nickel exposure. Interestingly, the majority of nickel-induced transcriptional changes occurred only after the termination of exposure. We found robust genome-wide alterations to the activating histone modification, H3K4me3, after the termination of nickel exposure, which coincided with the post-exposure gene expression changes. In addition, we found significant post-exposure alterations to the repressive histone modification, H3K27me3. By uncovering a new category of transcriptional and epigenetic changes, which occur only after the termination of exposure, this study sheds new light on the post-exposure effects of nickel and provides a novel understanding of the long-term deleterious consequences of nickel exposure on human health.

systems biology↗

bioRxiv2019

Investigating Coronary Artery Disease methylome through targeted bisulfite sequencing

BackgroundGene environment interactions leading to epigenetic alterations play pivotal role in the pathogenesis of Coronary Artery Disease (CAD). Altered DNA methylation is one such epigenetic factor that could lead to altered disease etiology. In this study, we comprehensively identified methylation sites in several genes that have been previously associated with young CAD patients.\n\nMethodsThe study population consisted of 42 healthy controls and 33 young CAD patients (age group < 50 years). We performed targeted bisulfite sequencing of promoter as well as genic regions of several genes in various pathways like cholesterol synthesis and metabolism, endothelial dysfunction, apoptosis, which are implicated in the development of CAD.\n\nResultsWe observed that the genes like GALNT2, HMGCR were hypermethylated in the promoter whereas LDLR gene promoter was hypomethylated indicating that intracellular LDL uptake was higher in CAD patients. Although APOA1 did not show significant change in methylation but APOC3 and APOA5 showed variation in methylation in promoter and exonic regions. Glucokinase (GCK) and endothelial nitric oxide synthase 3 (NOS3) were hyper methylated in the promoter. Genes involved in apoptosis (BAX/BCL2/AKT2) and inflammation (PHACTR1/LCK) also showed differential methylation between controls and CAD patients.\n\nConclusionsThis study is unique because it highlights important gene methylation alterations which might predict the risk of young CAD in Indian population. Large scale studies in different populations would be important for validating our findings and understanding the epigenetic events associated with CAD.

genomics↗