Biology subjects

Cohen, C. D.

Publications and source records attributed to Cohen, C. D..

11 recordsLinked to original sources

bioRxiv2025

Metabolic and Redox Pathway Dysregulation in HIV-Associated Coronary Endothelial Dysfunction

BackgroundPeople with HIV (PWH), even with sustained viral suppression on antiretroviral therapy (ART), remain at increased risk for cardiovascular disease. Coronary endothelial dysfunction, a sensitive marker of early vascular injury and a potential target for intervention is common in this population, but its biological basis remains unknown. MethodsWe performed a cross-sectional study combining in vivo coronary MRI and high-throughput serum proteomics to investigate mechanisms of coronary endothelial dysfunction in treated HIV. Forty-five virally suppressed PWH and twenty-nine age- and sex-matched healthy controls underwent coronary MRI during isometric handgrip exercise to quantify coronary endothelial function, defined as the percentage change in coronary cross-sectional area (%CSA) from rest to stress. An increase in coronary CSA <2% indicated endothelial dysfunction. Parallel serum proteomic profiling was performed using the SomaScan 7K platform, and differential protein expression between groups was analyzed using linear modeling (LIMMA). ResultsCoronary endothelial dysfunction was more prevalent in PWH with suppressed viral load compared to controls (67% vs 10%, p<0.001). Pathway analysis of differentially expressed proteins between participants with and without endothelial dysfunction highlighted significant dysregulation of glutathione dependent detoxification, oxidative metabolism and fatty acid {beta}-oxidation pathways in individuals with endothelial dysfunction (adjusted p value <0.05). ConclusionsEndothelial dysfunction in PWH on ART is associated with metabolic and redox imbalance. These findings highlight glutathione and fatty acid oxidation related pathways as potential therapeutic targets for reducing cardiovascular risk in this patient population.

immunology↗

bioRxiv2025

GSNOR deletion differentially alters age-related cardiac function in a sex-dependent manner.

S-nitrosoglutathione reductase (GSNOR), a regulator of protein S-nitrosylation (SNO), has been proposed as a longevity protein. GSNOR signaling has been implicated in both the alleviation and exacerbation of aging. In the context of ischemia reperfusion injury, we previously showed a sex-dependent response to GSNOR inhibition; cardiac damage was alleviated in males and exacerbated in females. Considering sex differences in the incidence of cardiovascular disease with age, we investigated the effect of GSNOR deletion (-/-) on age-related changes in cardiac function. We performed longitudinal 2D-echocardiography measurements in M-Mode on male and female, wildtype (WT) and GSNOR-/- mice at young (3-4 months), middle (13-15 months) and old age (18-20 months). Left ventricular wall thickness and ejection fraction decreased with age in WT mice but was maintained in GSNOR-/-. Western blot and GSNOR-activity assay showed GSNOR activity and expression decreased with age in WT females alone. Isolated cardiomyocyte force-coupling analysis showed increasing age was inversely correlated with sarcomere shortening and Ca2+ release kinetics in WT males, but not GSNOR-/-. WT females showed slower Ca2+ re-uptake after contraction and time to peak sarcomere shortening, but all other parameters were maintained. GSNOR-/- females exhibited slower Ca2+ re-uptake and decreased sarcomere shortening. Proteomic analysis of SNO from females showed upregulation of Pyruvate Dehydrogenase, E1 Beta and Dihydrolipoamide dehydrogenase in young WT females relative to middle-age mice. Together our data suggest that GSNOR deletion is cardioprotective by maintaining cardiac function in males; while in females the absence of GSNOR removes an age-essential SNO-imbalance, which may exacerbate pathologies.

physiology↗

bioRxiv2025

Tissue transcriptomics of endomyocardial biopsies reveals widespread molecular perturbations independent of leukocyte-rich foci in human myocarditis

BackgroundMyocarditis is an inflammatory disease of the myocardium, classically defined and graded by histologic criteria that emphasize immune infiltrates and focal cardiomyocyte injury. The broader transcriptional landscape and intercellular signaling networks underlying human myocarditis, particularly among non-immune cells, remain poorly understood. MethodsWe performed integrated spatial transcriptomic profiling of 38 endomyocardial biopsy (EMBx) specimens using two complementary platforms: 10X Visium FFPE and GeoMx Digital Spatial Profiling (DSP). The cohort included cases of histologically confirmed myocarditis, borderline myocarditis, and controls. For 10X Visium, data was refined by excluding leukocyte-enriched spots and enriching for cardiomyocyte-specific regions based on canonical marker expression. For GeoMx, immunohistochemistry-guided segmentation enabled targeted transcriptomic analysis of disparate cardiac cellular compartments. Differential gene expression was analyzed independently for each platform and subsequently integrated. These results were further leveraged to infer molecular interaction networks and ligand-receptor relationships in myocarditis relative to controls. ResultsBoth platforms revealed widespread gene expression changes consistent with immune activation in myocarditis and borderline myocarditis, particularly within cardiomyocyte-enriched regions. These included upregulation of HLA-A, HLA-DQA1, B2M, and CD74 in myocarditis, consistent with activation of major histocompatibility complex (MHC) class I and II related pathways. Molecular interaction analysis identified STAT1 and ISG15 as likely central immune signaling nodes. Ligand-receptor inference highlighted HLA-A, HLA-E, and HLA-DQA1 as key receptor hubs interacting with immune ligands such as IFNG, CD8A, and several members of the (NK) killer-cell immunoglobulin-like receptor (KIR) family. ConclusionsOur findings demonstrate that human myocarditis is characterized by widespread transcriptional dysregulation beyond immune cell foci, including upregulation of genes typically associated with professional antigen-presenting cells in cardiomyocytes. These insights extend our current understanding of myocarditis pathophysiology and suggest new opportunities for its diagnosis and therapeutic targeting.

immunology↗

bioRxiv2024

Single-cell transcriptional and epigenetic mapping reveals cellular and molecular mechanisms driving non-ischemic cardiac fibrosis

Cardiac fibrosis is a major cause of cardiac dysfunction. Recently, single-cell genomic approaches have revealed in unprecedented resolution the orchestrated cellular responses driving cardiac fibrosis. Yet, the fibrosis-causing phenotypes that emerge in the heart following non-ischemic cardiac stress, and the transcriptional circuits that govern cell identity and drive fibrosis, are not well understood. Applying a paired multiomic approach, we reveal key transcriptional circuits, in mouse and human hearts, which are associated with fibrosis development following non-ischemic cardiac insults, independent of disease model, species or biological sex. Strikingly, we find the key regulatory events driving fibrosis are reversible at the single-cell transcriptional and epigenomic level, further pointing to key factors regulating fibrosis development and resolution. The transcriptional regulators identified in this study represent promising targets to ameliorate the development of fibrosis in the context of chronic stressors such as aging and hypertension.

cell biology↗

bioRxiv2024

B cell-mediated antigen presentation promotes adverse cardiac remodeling in chronic heart failure

The cardio-splenic axis is a promising therapeutic target in ischemic heart failure (HF), but splenic-cardiac interactions after myocardial infarction (MI) are poorly understood. Here, we show that splenic follicular B cells drive ischemic HF via MHC class II-mediated antigen presentation. Transfer of splenic B cells from mice with ischemic HF induced adverse cardiac remodeling and modulated myocardial T-cells in naive recipients. Single-cell RNA sequencing of mouse and human post-MI B cells revealed upregulation of antigen-presentation related pathways. Mass spectrometry of the MHC II peptidome demonstrated enrichment of cardiac-derived peptides in MHC II molecules of splenic B cells from ischemic HF mice. B cell-specific deletion of MHC II suppressed adverse cardiac remodeling after adoptive transfer of post-MI splenic B cells. These results broaden our understanding of B-lymphocyte biology and point towards MHC II-mediated signaling in B-cells as a novel therapeutic target in ischemic HF.

immunology↗

bioRxiv2024

Single-nucleus RNA sequencing reveals cellular and molecular dynamics of white and brown adipose tissue in a mouse model of type-2 diabetes

Excessive adipose tissue expansion is often linked with type-2 diabetes. Despite recent efforts mapping adipose tissue changes in obesity using single-cell omics, an understanding of cellular and gene expression changes in a model of type 2 diabetes, and the transcriptional circuitry controlling it, is still lacking. Here, we use single-nucleus RNA sequencing to analyze the remodeling of gonadal white and interscapular brown adipose tissue from female and male mice with or without diabetes. Analysis of 51,877 nuclei revealed altered phenotypes in every cell population in type 2 diabetes. This included an immunoregulatory response, and changes in extracellular matrix, energy generation, and hormone responses. Key transcription factors were inferred as cell-specific and non-specific nodes controlling diabetes-linked phenotypes. Finally, female-to-male population heterogeneity and gene expression differences were observed. Here we provide a resource detailing how adipose tissue remodeling, and the molecular mechanisms governing it, may contribute to cardiometabolic disease.

cell biology↗

bioRxiv2023

B cells occupy a unique, dynamic, biological niche within the human myocardium

IntroductionGrowing evidence from animal models indicates that the myocardium hosts a population of B cells that play a role in the development of cardiomyopathy. However, there is minimal data on human myocardial B cells in the context of cardiomyopathy. MethodsWe integrated single-cell and single-nuclei datasets from 45 healthy human hearts, 70 hearts with dilated cardiomyopathy (DCM), and 8 hearts with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). Interactions between B cells and other cell types were investigated using the CellChat Package. Differential gene expression analysis comparing B cells across conditions was performed using DESeq2. Pathway analysis was performed using Ingenuity, KEGG, and GO pathways analysis. ResultsWe identified 1,100 B cells, including naive B cells and plasma cells. B cells showed an extensive network of interactions within the healthy myocardium that included outgoing signaling to macrophages, T cells, endothelial cells, and pericytes, and incoming signaling from endothelial cells, pericytes, and fibroblasts. This niche relied on ECM-receptor, contact, and paracrine interaction; and changed significantly in the context of cardiomyopathy, displaying disease-specific features. Differential gene expression analysis showed that in the context of DCM both naive and plasma B cells upregulated several pathways related to immune activation, including upregulation of oxidative phosphorylation, upregulation of leukocyte extravasation, and, in naive B cells, antigen presentation. DiscussionThe human myocardium contains naive B cells and plasma cells, integrated into a diverse and dynamic niche that has distinctive features in healthy myocardium, DCM, and ARVC. Naive myocardial-associated B cells likely contribute to the pathogenesis of human DCM.

immunology↗

bioRxiv2022

Single-cell transcriptomics reveals a mechanosensitive injury signaling pathway in early diabetic nephropathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease and histopathologic glomerular lesions are among the earliest structural alterations of DN. However, the signaling pathways that initiate these glomerular alterations are incompletely understood. To delineate the cellular and molecular basis for DN initiation, we performed single-cell and bulk RNA sequencing of renal cells from type 2 diabetes mice (BTBR ob/ob) at the early stage of DN. Analysis of differentially expressed genes revealed glucose-independent responses in glomerular cell types. The gene regulatory network upstream of glomerular cell programs suggested the activation of mechanosensitive transcriptional pathway MRTF-SRF predominantly taking place in mesangial cells. Importantly, activation of MRTF-SRF transcriptional pathway was also identified in DN glomeruli in independent patient cohort datasets. Furthermore, ex vivo kidney perfusion suggested that the regulation of MRTF-SRF is a common mechanism in response to glomerular hyperfiltration. Overall, our study presents a comprehensive single-cell transcriptomic landscape of early DN, highlighting mechanosensitive signaling pathways as novel targets of diabetic glomerulopathy.

molecular biology↗

bioRxiv2022

Maternal diet and gut microbiota influence predisposition to cardiovascular disease in the offspring

Cardiovascular disease is one of the most significant causes of death globally, especially in regions where unhealthy diets are prevalent and dietary fibre intake is low.1,2 Fibre, particularly prebiotic types that feed gut microbes, is essential for maintaining healthy gut microbial ecosystems.3 One assumption has been that cardiovascular health relates directly to lifestyle choices in adult life. Here, we show in mice that some of these benefits operate from the prenatal stage and relate to the diet and gut microbiome of the mother. Intake of fibre during pregnancy shaped the mothers gut microbiome, which had a lasting founding effect on the offsprings microbial composition and function. Maternal fibre intake during pregnancy significantly changed the cardiac cellular and molecular landscape in the offspring, protecting them against the development of cardiac hypertrophy, remodelling, and inflammation. These suggest a role for foetal exposure to maternal-derived gut microbial metabolites, which are known to cross the placenta and drive epigenetic changes. Maternal fibre intake led to foetal epigenetic reprogramming of the atrial natriuretic peptide gene (Nppa), protective against heart failure. These results underscore the importance of dietary intake and the gut microbiome of the mother during pregnancy for cardiovascular disease in the offspring.

microbiology↗

bioRxiv2019

High-resolution transcriptomic profiling of the heart during chronic stress reveals cellular drivers of cardiac fibrosis and hypertrophy

BackgroundCardiac fibrosis is a key antecedent to many types of cardiac dysfunction including heart failure. Physiological factors leading to cardiac fibrosis have been recognized for decades. However, the specific cellular and molecular mediators that drive cardiac fibrosis, and the relative impact of disparate cell populations on cardiac fibrosis, remain unclear. MethodsWe developed a novel cardiac single-cell transcriptomics strategy to characterize the cardiac cellulome--the network of cells that forms the heart. This method was utilized to profile the cardiac cellular ecosystem in response to two weeks of continuous administration of Angiotensin II, a pro-fibrotic stimulus which drives pathological cardiac remodeling. ResultsThis analysis uncovered multiple cell populations contributing to pathological remodeling of the extracellular matrix of the heart. Two phenotypically distinct fibroblast populations emerged after induction of tissue stress to promote fibrosis in the absence of smooth muscle actin-expressing myofibroblasts, a key pro-fibrotic cell population. Further, the cellular responses to Angiotensin II and the relative abundance of fibrogenic cells were sexually dimorphic. ConclusionsThese results offer a valuable resource for exploring the cardiac cellular landscape in health and after chronic cardiovascular stress. These data provide insights into the cellular and molecular mechanisms that promote pathological remodeling of the mammalian heart, highlighting early transcriptional changes which precede chronic cardiac fibrosis.

cell biology↗

bioRxiv2018

Inflammatory and JAK-STAT Pathways as Shared Molecular Targets for ANCA-Associated Vasculitis and Nephrotic Syndrome

BackgroundGlomerular diseases of the kidney are presently differentiated, diagnosed and treated according to conventional clinical or structural features. While etiologically diverse, these diseases share common clinical features including but not limited to reduced glomerular filtration rate, increased serum creatinine and proteinuria suggesting shared pathogenic mechanisms across diseases. Renal biopsies from patients with nephrotic syndrome (NS) or ANCA-associated vasculitis (AAV) were evaluated for molecular signals cutting across conventional disease categories as candidates for therapeutic targets.\n\nMethodsRenal biopsies were obtained from patients with NS (minimal change disease, focal segmental glomerulosclerosis, or membranous nephropathy) (n=187) or AAV (granulomatosis with polyangiitis or microscopic polyangiitis) (n=80) from the Nephrotic Syndrome Study Network (NEPTUNE) and the European Renal cDNA Bank. Transcriptional profiles were assessed for shared disease mechanisms.\n\nResultsIn the discovery cohort, 10-25% transcripts were differentially regulated versus healthy controls in both NS and AAV, >500 transcripts were shared across diseases. The majority of shared transcripts (60-77%) were validated in independent samples. Therapeutically targetable networks were identified, including inflammatory JAK-STAT signaling. STAT1 eQTLs were identified and STAT1 expression associated with GFR-based outcome. A transcriptional STAT1 activity score was generated from STAT1-regulated target genes which correlated with CXCL10 (p<0.001), a JAK-STAT biomarker, predictors of CKD progression, interstitial fibrosis (r=0.41, p<0.001), and urinary EGF (r=-0.51, p<0.001).\n\nConclusionAAV and NS caused from histopathologically distinct disease categories share common intra-renal molecular pathways cutting across conventional disease classifications. This approach provides a starting point for de novo drug development, and repurposing efforts in rare kidney diseases.

systems biology↗