Biology subjects

Ganesh, S. K.

Publications and source records attributed to Ganesh, S. K..

6 recordsLinked to original sources

bioRxiv2025

VGLL3-centered network connects placental, vascular, and immune defects in preeclampsia

Preeclampsia affects approximately 1 in 10 pregnancies, leading to severe complications and long-term health risks for both mother and offspring. While the etiology remains unclear, preeclampsia has been linked to both autoimmunity and the timing of menarche. Through human single-cell and spatial analyses, coupled with in vitro, in vivo, and ex vivo models, we demonstrate that VGLL3, a transcription co-regulator in the Hippo pathway, is upregulated in preeclamptic placentas. VGLL3 promotes immune activation, impairs trophoblast differentiation, and induces endothelial dysfunction, all of which contribute to pregnancy-related hypertension, fetal growth restriction, and offspring mortality. Our data reveal that VGLL3 acts upstream of preeclampsia-associated processes, including the production of sFLT1, a key biomarker of the disease. Notably, targeting VGLL3--either by genetic deletion in mouse placentas or through therapeutic inhibition in human placentas--protects against preeclampsia and alleviates disease pathology. These findings position VGLL3 as a promising novel therapeutic target for preeclampsia.

immunology↗

bioRxiv2024

Coordination between cytoskeletal organization, cell contraction and extracellular matrix development, is depended on LOX for aneurysm prevention

Distinct, seemingly independent, cellular pathways affecting intracellular machineries or extracellular matrix (ECM) deposition and organization, have been implicated in aneurysm formation. One of the key genes associated with the pathology in both humans and mice is Lysyl oxidase (LOX), a secreted ECM-modifying enzyme, highly expressed in medial vascular smooth muscle cells. To dissect the mechanisms leading to aneurysm development, we conditionally deleted Lox in smooth muscle cells. We find that cytoskeletal organization is lost following Lox deletion. Cell culture assays and in vivo analyses demonstrate a cell-autonomous role for LOX affecting myosin light chain phosphorylation and cytoskeletal assembly resulting in irregular smooth muscle contraction. These results not only highlight new intracellular roles for LOX, but notably they link between multiple processes leading to aneurysm formation suggesting LOX coordinates ECM development, cytoskeletal organization and cell contraction required for media development and function.

cell biology↗

bioRxiv2022

Tissue-specific and tissue-agnostic effects of genome sequence variation modulating blood pressure

Genome-wide association studies (GWAS) have mapped thousands of variants for numerous polygenic traits and diseases. However, with some exceptions, mechanistic understanding of which precise variants affect which genes in which tissues to modulate trait variation is still lacking. To this end, we introduce a novel class of genomic analyses applicable to any complex trait using GWAS together with gene expression and chromatin accessibility data from multiple tissues. Here we identify the transcription factors (TFs) and regulatory variants within active enhancers regulating specific genes in individual tissues to explain trait heritability of blood pressure (BP), a classical polygenic trait. We show that kidney-, adrenal-, heart-, and arterial-specific regulatory variants contribute to 2.5%, 5.3%, 7.7%, and 11.8% of variant heritability, respectively. Collectively, [~]500,000 predicted regulatory variants across these four tissues explain 33.4% of variant heritability. We demonstrate that these variants are enriched in enhancers binding specific TFs in each tissue. Our findings suggest that gene regulatory networks perturbed by common regulatory variants in a tissue relevant to a phenotype are the primary source of interindividual variation of BP. These studies provide an approach to scan each human tissue for its physiological contribution to a trait.

genetics↗

bioRxiv2020

A system for phenotype harmonization in the NHLBI Trans-Omics for Precision Medicine (TOPMed) Program

Genotype-phenotype association studies often combine phenotype data from multiple studies to increase power. Harmonization of the data usually requires substantial effort due to heterogeneity in phenotype definitions, study design, data collection procedures, and data set organization. Here we describe a centralized system for phenotype harmonization that includes input from phenotype domain and study experts, quality control, documentation, reproducible results, and data sharing mechanisms. This system was developed for the National Heart, Lung and Blood Institutes Trans-Omics for Precision Medicine (TOPMed) program, which is generating genomic and other omics data for >80 studies with extensive phenotype data. To date, 63 phenotypes have been harmonized across thousands of participants from up to 17 TOPMed studies per phenotype. We discuss the challenges faced in this undertaking and how they were addressed. The harmonized phenotype data and associated documentation have been submitted to National Institutes of Health data repositories for controlled-access by the scientific community. We also provide materials to facilitate future harmonization efforts by the community, which include (1) the code used to generate the 63 harmonized phenotypes, enabling others to reproduce, modify or extend these harmonizations to additional studies; and (2) results of labeling thousands of phenotype variables with controlled vocabulary terms.

genetics↗

bioRxiv2019

The in vivo endothelial cell translatome is highly heterogeneous across vascular beds

Endothelial cells (ECs) are highly specialized across vascular beds. However, given their interspersed anatomic distribution, comprehensive characterization of the molecular basis for this heterogeneity in vivo has been limited. By applying endothelial-specific translating ribosome affinity purification (EC-TRAP) combined with high-throughput RNA sequencing analysis, we identified pan EC-enriched genes and tissue-specific EC transcripts, which include both established markers and genes previously unappreciated for their presence in ECs. In addition, EC-TRAP limits changes in gene expression following EC isolation and in vitro expansion, as well as rapid vascular bed-specific shifts in EC gene expression profiles as a result of the enzymatic tissue dissociation required to generate single cell suspensions for fluorescence-activated cell sorting (FACS) or single cell RNA sequencing analysis. Comparison of our EC-TRAP to published single cell RNA sequencing data further demonstrates considerably greater sensitivity of EC-TRAP for the detection of low abundant transcripts. Application of EC-TRAP to examine the in vivo host response to lipopolysaccharide (LPS) revealed the induction of gene expression programs associated with a native defense response, with marked differences across vascular beds. Furthermore, comparative analysis of whole tissue and TRAP-selected mRNAs identified LPS-induced differences that would not have been detected by whole tissue analysis alone. Together, these data provide a resource for the analysis of EC-specific gene expression programs across heterogeneous vascular beds under both physiologic and pathologic conditions.\n\nSignificanceEndothelial cells (ECs), which line all vertebrate blood vessels, are highly heterogeneous across different tissues. The present study uses a genetic approach to specifically tag mRNAs within ECs of the mouse, thereby allowing recovery and sequence analysis to evaluate the EC-specific gene expression program directly from intact organs. Our findings demonstrate marked heterogeneity in EC gene expression across different vascular beds under both normal and disease conditions, with a more accurate picture than can be achieved using other methods. The data generated in these studies advance our understanding of EC function in different blood vessels and provide a valuable resource for future studies.

genomics↗

bioRxiv2018

Clinical implications of identifying pathogenic variants in aortic dissection patients with whole exome sequencing

BackgroundThoracic aortic dissection is an emergent life-threatening condition. Routine screening for genetic variants causing thoracic aortic dissection is not currently performed for patients or their family members.\n\nMethodsWe performed whole exome sequencing of 240 patients with thoracic aortic dissection (n=235) or rupture (n=5) and 258 controls matched for age, sex, and ancestry. Blinded to case-control status, we annotated variants in 11 genes for pathogenicity.\n\nResultsTwenty-four pathogenic variants in 6 genes (COL3A1, FBN1, LOX, PRKG1, SMAD3, TGFBR2) were identified in 26 individuals, representing 10.8% of aortic cases and 0% of controls. Among dissection cases, we compared those with pathogenic variants to those without and found that pathogenic variant carriers had significantly earlier onset of dissection (41 vs. 57 years), higher rates of root aneurysm (54% vs. 30%), less hypertension (15% vs. 57%), lower rates of smoking (19% vs. 45%), and greater incidence of aortic disease in family members. Multivariable logistic regression showed significant risk factors associated with pathogenic variants are age <50 [odds ratio (OR) = 5.5; 95% CI: 1.6-19.7], no history of hypertension (OR=5.6; 95% CI: 1.4-22.3) and family history of aortic disease (mother: OR=5.7; 95% CI: 1.4-22.3, siblings: OR=5.1; 95% CI 1.1-23.9, children: OR=6.0; 95% CI: 1.4-26.7).\n\nConclusionsClinical genetic testing of known hereditary thoracic aortic dissection genes should be considered in patients with aortic dissection, followed by cascade screening of family members, especially in patients with age-of-onset of aortic dissection <50 years old, family history of aortic disease, and no history of hypertension.

genetics↗