Abstract 015: Hypertensive Stretch On The Regulation Of The Immunological Synapse And Secretomes Of Male And Female Renal Endothelial Cells

Abstract

Immune cells and inflammation contribute to the development of hypertension and renal injury. While endothelial cells are recognized as professional antigen presenting cells, they can express both Major Histocompatibility Complex (MHC) I and II and possess antigen-presenting functions. Endothelial cell activation and inflammation are critical in the development of hypertension. However, the mechanisms by which inflammatory hypertensive stimuli regulate renal endothelial immunological synapse proteins remains unknown. We hypothesize that inflammatory hypertensive mechanical stretch promotes the regulation of MHC I and II and costimulatory molecules on mouse renal endothelial cells (MRECs) in a sex-dependent manner. MRECs derived from both sexes underwent normotensive (5%; 1 Hz), hypertensive (10%, 1 Hz), and supra-hypertensive (15% 1 Hz) uniaxial cyclical stretch for 48 hours. We then assessed CD80, CD86, MHC II, MHC I, CD70, and CD40 by immunoblot analysis. A proteome multiplex assay was used to analyze male and female MREC secretomes during 5%, 10%, and 15% stretch. Hypertensive 10% stretch significantly increased only CD40 expression in males, while it upregulated CD80 and CD70 expression in females (p<0.05). Under 15% stretch, males significantly upregulated MHC I, CD70, and CD40 compared to I-Ab, CD80, CD86, and CD70 in females MRECs (p<0.05). We investigated sex differences and found that females significantly increased CD70 in both 10% and 15% stretch compared to males MRECs (p<0.05). We compared sex differences from our secretome proteomics in male and female MRECs at 10% and 15% stretch. We found that pathways associated with wound healing, Th17 activation, IL-6, and NF-κB signaling were upregulated in male MRECs undergoing 10% stretch. Interestingly, Th17 activation, natural killer cell signaling, and IL-23 signaling were downregulated in female MRECs undergoing 10% stretch. Under 15% stretch, IL-13 signaling, HMBG1 signaling, B cell signaling, and IL-13 signaling were downregulated in MRECs from both sexes. Our data provides novel insights into how inflammatory hypertensive stretch regulates immunological synapse proteins and secretomes in renal endothelial cells by stretch and sex-dependent manner.