Stolze, L. | bioRxiv Science

bioRxiv2024

Cytokine and Chemokine Receptor Profiles in Adipose Tissue Vasculature Unravel Endothelial Cell Responses in HIV

Chronic systemic inflammation contributes to a substantially elevated risk of myocardial infarction in people living with HIV (PLWH). Endothelial cell dysfunction disrupts vascular homeostasis regulation, increasing the risk of vasoconstriction, inflammation, and thrombosis that contribute to cardiovascular disease. Our objective was to study the effects of plasma from PLWH on endothelial cell (EC) function, with the hypothesis that cytokines and chemokines are major drivers of EC activation. We first broadly phenotyped chemokine and cytokine receptor expression on arterial ECs, capillary ECs, venous ECs, and vascular smooth muscle cells (VSMCs) in adipose tissue in the subcutaneous adipose tissue of 59 PLWH using single cell transcriptomic analysis. We used CellChat to predict cell-cell interactions between ECs and other cells in the adipose tissue and Spearman correlation to measure the association between ECs and plasma cytokines. Finally, we cultured human arterial ECs (HAECs) in plasma-conditioned media from PLWH and performed bulk sequencing to study the direct effects ex-vivo. We observed that arterial and capillary ECs expressed higher interferon and tumor necrosis factor (TNF) receptors. Venous ECs had more interleukin (IL)-1R1 and ACKR1 receptors, and VSMCs had high significant IL-6R expression. CellChat predicted ligand-receptor interactions between adipose tissue immune cells as senders and capillary ECs as recipients in TNF-TNFRSF1A/B interactions. Chemokines expressed largely by capillary ECs were predicted to bind ACKR1 receptors on venous ECs. Beyond the adipose tissue, the proportion of venous ECs and VSMCs were positively plasma IL-6. In ex-vivo experiments, HAECs cultured with plasma-conditioned media from PLWH expressed transcripts that enriched for the TNF- and reactive oxidative phosphorylation pathways. In conclusion, ECs demonstrate heterogeneity in cytokine and chemokine receptor expression. Further research is needed to fully elucidate the role of cytokines and chemokines in EC dysfunction and to develop effective therapeutic strategies.

cell biology↗

bioRxiv2023

Coronary Artery Disease risk variant dampens the expression of CALCRL by reducing HSF binding to shear stress responsive enhancer in endothelial cells

Coronary artery disease (CAD) is one of the major causes of mortality worldwide. Recent genome-wide association studies have started to unravel the genetic architecture of the disease. Such efforts have identified Calcitonin receptor-like (CALCRL), an important mediator of the endothelial fluid shear stress response, associated with CAD risk variants. In this study we functionally characterized the non-coding regulatory elements carrying CAD risks SNPs and studied their role in the regulation of CALCRL expression in endothelial cells. We demonstrate that rs880890-harboring regulatory element exhibits high enhancer activity and significant allelic bias with A allele showing 40% more activity than G allele. We also observed that the A allele of rs880890 is favored over the G allele under shear stress. CRISPR deletion of rs880890-enhancer resulted in downregulation of CALCRL expression. EMSA further showed that heat shock factors are binding to the enhancer with a preference for A allele over the G allele. In line with this, HSF1 knockdown resulted in a significant decrease in CALCRL expression. CALCRL knockdown as well as variant perturbation experiments confirmed the role of CALCRL in the regulation of eNOS, apelin, angiopoietin, prostaglandins and endothelin-1 signaling pathways while demonstrating a significant decrease in cell proliferation and tube formation. Overall, our results demonstrate the existence of an endothelial-specific heat shock factor regulated transcriptional enhancer carrying a CAD risk SNP rs880890 that regulates CALCRL expression. Better understanding of CALCRL gene regulation and the role of SNPs in modulation of CALCRL expression could provide important steps towards understanding genetic regulation of shear stress signaling responses.

genetics↗