Biology subjects

Arumugam, T.

Publications and source records attributed to Arumugam, T..

4 recordsLinked to original sources

bioRxiv2025

Intermittent Fasting Reprograms Chromatin Accessibility to Modulate Gene Expression in Brain and Muscle

Intermittent fasting (IF), a dietary regimen that mimics the natural feeding patterns observed across diverse organisms--from single-celled life to mammals--is thought to activate systemic survival responses and confer health benefits. However, the molecular mechanisms underlying these effects remain poorly understood. In this study, we utilized ATAC-Seq and RNA-Seq to investigate how IF influences chromatin accessibility and gene expression in brain and muscle tissues of mice, compared to ad libitum feeding. Our results reveal that IF induces significant changes in chromatin accessibility, modulating pathways related to metabolism, ribosome function, HIF-1 signaling, and glycolysis. Motif analysis identified tissue-specific transcription factors enriched in IF-regulated regions, including Sp1, Mef2a, NeuroD2, Banp, and NFIA in the brain, and SMAD4, TCF4, STAT5B, NKX3-1, and ZEB2 in muscle. Integrative analysis of ATAC-Seq and RNA-Seq data demonstrated that IF upregulates 50 genes and downregulates 15 in the cortex, while upregulating 31 genes and downregulating 10 in muscle. These gene expression changes are linked to pathways associated with neuroprotection and enhanced muscle function, offering mechanistic insights into the health benefits of IF. Our findings underscore the role of IF-induced chromatin remodeling in driving adaptive gene regulation.

bioinformatics↗

bioRxiv2024

Spatial Transcriptomic Analysis Reveals HDAC Inhibition Modulates Microglial Dynamics to Protect Against Ischemic Stroke in Mice

Ischemic stroke significantly contributes to global morbidity and disability through a cascade of neurological responses. Microglia, the immune modulators within the brain, exhibit dual roles in exacerbating and ameliorating ischemic injury through neuroinflammatory and neuroprotective roles, respectively. Despite emerging insights into microglias role in neuronal support, the potential of epigenetic intervention to modulate microglial activity remains largely unexplored. We have previously shown that sodium butyrate, a histone deacetylase inhibitor (HDACi) epigenetically regulates inflammatory response of microglia after ischemic stroke and this study was aimed to characterize the transcriptomic profiles of microglia and their spatial distribution in the stroke brain followed by HDACi administration. We hypothesized that the administration of HDACi epigenetically modulates microglial activation and a region-specific microglial phenotype in the stroke brain, shifting their phenotype from neurotoxic to neuroprotective and facilitating neuronal repair and recovery in the ischemic penumbra. Utilizing a rodent model of middle cerebral artery occlusion (MCAo), spatial transcriptomics and 3D morphometric reconstruction techniques were employed to investigate microglial responses in critical penumbral regions, such as the hippocampus, thalamus, cortex and striatum following HDACi administration. We found that HDACi significantly altered the microglial transcriptomic landscape involving biological pathways of neuroinflammation, neuroprotection and phagocytosis as well as morphological phenotype, promoting a shift towards reparative, neurotrophic profiles within the ischemic penumbra. These changes were also associated with enhanced neuronal survival and reduced neuroinflammation in specific regions in the ischemic brain. By elucidating the mechanisms through which HDAC inhibition influences microglial function, our findings propose therapeutic avenues for neuroprotection and rehabilitation in ischemic stroke, and possibly other neurodegenerative conditions that involve microglia-mediated neuroinflammation.

neuroscience↗

bioRxiv2020

Hippocampal Transcriptome Profiling Reveals Common Disease Pathways in Chronic Hypoperfusion and Ageing

Vascular dementia (VaD) is a progressive cognitive impairment of vascular etiology. VaD is characterized by cerebral hypoperfusion, increased blood-brain barrier permeability and white matter lesions. An increased burden of VaD is expected due to rapidly aging populations. The hippocampus is particularly susceptible to hypoperfusion, and the resulting memory impairment may play a crucial role in VaD. Here we have investigated the hippocampal gene expression profile of young and old mice subjected to chronic cerebral hypoperfusion by bilateral common carotid artery stenosis (BCAS). Our data in sham-operated young and aged mice show the normal age-associated decline in cerebral blood flow and differential gene expression. BCAS and ageing caused broadly similar effects, however, BCAS-induced changes in hippocampal gene expression differed between young and aged mice. Specifically, transcriptomic analysis indicated that in comparison to young sham mice, many pathways altered by BCAS in young mice resembled those present in sham aged mice. Immunoblot analyses confirmed these findings. Finally, relative to young sham mice the cell type-specific profile of genes in both young BCAS and old sham animals further revealed common cell-specific genes. Our data provide a genetic-based molecular framework for chronic hypoperfusion-induced hippocampal damage and reveal common cellular signaling pathways likely to be important in the pathophysiology of VaD.

neuroscience↗

bioRxiv2020

Integrative Epigenomic and Transcriptomic Analysis Reveals Robust Metabolic Switching in the Brain During Intermittent Fasting

Intermittent fasting (IF) is a lifestyle intervention comprising a dietary regimen in which energy intake is restricted via alternating periods of fasting and ad libitum food consumption, without compromising nutritional composition. While epigenetic modifications can mediate effects of environmental factors on gene expression, no information is yet available on potential effects of IF on the epigenome. In this study, we found that IF causes modulation of histone H3 lysine 9 trimethylation (H3K9me3) epigenetic mark in the cerebellum of male C57/BL6 mice, which in turn orchestrates a plethora of transcriptomic changes involved in the robust metabolic switching processes commonly observed during IF. Interestingly, both epigenomic and transcriptomic modulation continued to be observed after refeeding, suggesting that memory of the IF-induced epigenetic change is maintained at the locus. Notably though, we found that termination of IF results in a loss of H3K9me3 regulation of the transcriptome. Collectively, our study characterizes a novel mechanism of IF in the epigenetic-transcriptomic axis, which controls myriad metabolic process changes. In addition to providing a valuable and innovative resource, our systemic analyses reveal molecular framework for understanding how IF impacts the metaboloepigenetics axis of the brain. Highlights{circ} Intermittent fasting (IF) and refeeding modifies epigenome in the cerebellum {circ}Integrative epigenomic and transcriptomic analyses revealed metabolic switching {circ}IF affects the metaboloepigenetics axis in regulating metabolic processes {circ}Integrative analyses revealed a loss of epigenetic reprogramme following refeeding

neuroscience↗