Biology subjects

Chadha, R. S.

Publications and source records attributed to Chadha, R. S..

5 recordsLinked to original sources

bioRxiv2026

MetaboRamics: Highly multiplexed metabolic imaging by stimulated Raman for spatial metabolomics in live cells

Cellular metabolism is highly dynamic, intertwined and spatially heterogenous, yet methods that can simultaneously visualize multiple metabolic pathways in living systems remain largely limited. Here, we present MetaboRamics: highly multiplexed metabolic imaging by stimulated Raman for spatial metabolomics in live cells. Through rational probe selection and careful optimization, isotope editing, and robust spectral unmixing, we establish a metabolic palette of 16-colors spanning glucose uptake and utilization, lipid uptake and synthesis, choline metabolism, DNA synthesis, and amino acid incorporation in addition to endogenous proteins, lipids and redox signals. Incorporation of organelle-targeted Raman probes further enables spatial interactomics and assessment of organelle activities. Applying MetaboRamics to epithelial-mesenchymal transition (EMT), we observe metabolic rewiring in mesenchymal cells, reflected by reduced glucose-derived biomass, lipid turnover, protein synthesis, and altered redox balance. Finally, we perform optical phenotyping of cellular states under metabolic stress of serum deprivation, nutrient overload (fructose, and saturated fatty acid), inflammation, and pharmacological perturbations to reveal subcellular metabolic changes. This work fully realizes the potential of stimulated Raman scattering (SRS) microscopy for super-multiplexed metabolic imaging by establishing, for the first time, a 16-plex platform for live-cell spatial metabolomics.

cell biology↗

bioRxiv2026

Optical metabolic imaging of the tricarboxylic acid cycle

The tricarboxylic acid (TCA) cycle lies at the core of cellular metabolism, integrating energy production, biosynthesis and redox homeostasis, yet direct quantitative imaging of its activity in living systems remains challenging. Here we introduce MATRIX-SRS (Metabolic Activity TRacing of the trIcarboXylic acid cycle by Stimulated Raman Scattering microscopy), a platform enabling spatially resolved quantification of TCA-linked metabolism in live cells. Using emerging deuterium-labeled probes, MATRIX-SRS visualizes subcellular TCA-associated carbon-deuterium bonds in live cancer cells and neurons. We then integrate density functional theory, reaction network mapping, and hyperspectral MATRIX-SRS to construct a robust in situ metabolic quantification pipeline. Integrating MATRIX-SRS with isotope-tracing mass spectrometry, we reveal a global attenuation of TCA activity during epithelial-to-mesenchymal transition, providing deep molecular insights. Applying this framework, we further quantify changes in deuterium-labeled biomass in absolute concentrations for the first time, under native and drug-treated conditions, establishing a generalizable foundation for live quantitative spatial metabolomics.

biochemistry↗

bioRxiv2025

Single-Cell Metabolic Imaging Reveals Glycogen Driven-Adaptations in Endothelial Cells

Endothelial dysfunction (ED) is a defining feature of diabetes mellitus (DM) and a key contributor to many metabolic and cardiovascular diseases. Endothelial cells (ECs) are known to be highly glycolytic and primarily rely on glucose to meet their energy demands. However, the role of glycogen metabolism in ECs remains poorly characterized due to a lack of suitable tools. Here, we utilize stimulated Raman scattering (SRS) microscopy to investigate subcellular glycogen metabolism in live ECs under stress conditions associated with highly prevalent diabetes and diabetic complications. We demonstrate that ECs exposed to a diabetes-mimicking milieu- high glucose and tumor necrosis factor (TNF-)- divert excess glucose toward subcellular glycogen storage, and that this storage capacity is significantly enhanced by the inhibition of glycogen synthase kinase 3 (GSK3). Pulse-chase experiments uncover glycogen dynamics and reveal that glycogen is rapidly mobilized under glucose starvation, highlighting its role as an immediate energy reserve in ECs. We further extend the capabilities of SRS metabolic imaging to visualize glutamine and lactate metabolism for the first time, directly showcasing the reliance of ECs on these alternative carbon substrates during glucose deprivation. Our results indicate that ECs containing glycogen exhibit a reduced immediate metabolic demand for these gluconeogenic substrates in the absence of extracellular glucose. These findings suggest that glycogen may play a broader role beyond energy reserves in ECs by modulating stress-responsive metabolic adaptations and may offer potential therapeutic opportunities to address diabetes-induced ED and related cardiometabolic diseases.

cell biology↗

bioRxiv2025

Endothelial AGO1 Drives Vascular Inflammation and Atherosclerosis via a Non-Canonical Nuclear Mechanism

BACKGROUNDEndothelial cell (EC) dysfunction is a cause and consequence of vascular inflammation and lipid dysregulation in atherosclerosis, yet the molecular drivers linking EC dysfunction to systemic metabolic derangements remain incompletely understood. Moreover, whether inhibiting an endogenous gene in ECs can impact liver function, lipid profile, and the vascular inflammation in the context of atherosclerosis has not been demonstrated. We previously identified Argonaute 1 (AGO1), a component of the RNA-induced silencing complex, as a regulator of EC function in angiogenesis and obesity. However, the role of endothelial AGO1 in vascular inflammation and liver function in the context of hyperlipidemia and atherosclerosis is unknown. METHODSEC-conditional AGO1 knockout (EC-AGO1-KO) and wildtype mice were subjected to pro-atherosclerotic models induced by AAV9-PCSK9 coupled with a Western diet or partial carotid ligation. Metabolic and vascular phenotype and gene expression were analyzed. In human liver sinusoidal and aortic ECs, AGO1 was knocked down using antisense oligonucleotides (ASO), followed by assessment of inflammatory responses (qPCR, RNA-seq, ELISA, and monocyte adhesion assays). To identify the molecular mechanisms linking AGO1 and EC inflammation, Cut&Tag sequencing, chromatin immunoprecipitation, immunofluorescence, proximal ligation assay, and co-immunoprecipitation were performed. The therapeutic effect of AGO1 inhibition was assessed using ASO-delivered via lipid nanoparticle (LNP) for systemic distribution and monocyte membrane-coated nanoparticles (MoNP) to target the inflamed endothelium. RESULTSEC-AGO1-KO mice exhibited improved plasma lipid profiles, reduced hepatic steatosis, inflammation, and fibrosis, and decreased aortic atherosclerotic burden. AGO1 knockdown in ECs attenuated inflammatory responses. Mechanistically, AGO1 interacted with NF-{kappa}B p65 and promoted p65 nuclear translocation and the transcriptional activation of pro-inflammatory genes, including ICAM1 and THBS1. AGO1-ASO delivered through LNP or MoNP achieved the anti-inflammatory, anti-hyperlipidemic, and anti-atherosclerotic effects, recapitulating the phenotypes observed with EC-AGO1-KO. CONCLUSIONSEndothelial AGO1 promotes vascular inflammation and liver dysfunction in the context of hyperlipidemia and atherosclerosis, in part through a non-canonical nuclear action of AGO1 as an NF-{kappa}B coactivator. Inhibition of endothelial AGO1 provides the dual benefits of ameliorating lipid dysregulation and suppressing vascular inflammation. These results highlight EC-AGO1 as a possible therapeutic target for atherosclerosis and cardiometabolic diseases.

pathology↗

bioRxiv2024

Mapping Endothelial-Macrophage Interactions in Diabetic Vasculature: Role of TREM2 in Vascular Inflammation and Ischemic Response

Diabetes mellitus (DM) significantly accelerates vascular diseases like peripheral arterial disease (PAD). Endothelial cells (ECs) and macrophages (M{Phi}s) singularly and synergistically are important contributors to DM-associated vascular dysfunction. Single-cell (sc) profiling technologies are revealing the true heterogeneity of ECs and M{Phi}s, but how this cellular diversity translates to cell-cell interactions, and consequentially vascular function, remains unknown. We leveraged scRNA sequencing and spatial transcriptome (ST) profiling to analyze human mesenteric arteries from non-diabetic (ND) and type 2 diabetic (T2D) donors. We generated a transcriptome and interactome map encompassing the major arterial cells and highlighted Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) as a top T2D-induced gene in mononuclear phagocytes (MPs), with concomitant increases of TREM2 ligands in ECs. We verified DM-associated TREM2 induction in cell and mouse models, and found that TREM2 inhibition decreases pro-inflammatory responses in MPs and ECs, as well as increases EC migration in vitro. Furthermore, TREM2 inhibition using a neutralizing antibody enhanced ischemic recovery and flow reperfusion in DM mice subjected to hindlimb ischemia, suggesting that TREM2 promotes ischemic injury in DM. Finally, in human PAD, co-existing DM was associated with greater expression of TREM2 and its interaction with ECs, with a further increase in ischemic tissue compared to patient-matched non-ischemic tissue. Collectively, our study presents the first atlas of human diabetic vessels with single cell and spatial resolution, and identifies TREM2-EC interaction as a key driver of diabetic vasculopathies, the targeting of which may offer an opportunity to ameliorate vascular dysfunction associated with DM-PAD.

cell biology↗