#3769 MECHANOSENSITIVE ION CHANNEL PIEZO1 MEDIATES BLOOD PRESSURE HOMEOSTASIS BY REGULATING RENIN EXPRESSION IN MICE

Abstract Background and Aims The renin-angiotensin system (RAS) plays a crucial role in the maintenance of fluid-electrolyte and blood pressure homeostasis. Renin, the step-limiting protease of the RAS, is produced, stored, and secreted by the renal juxtaglomerular (JG) cells, which are closely regulated by the blood pressure. Studies have shown that local blood flow-associated shear stress play an important role in renin expression and secretion. To date, however, the molecular identity through which JG cells respond to the blood pressure remains unclear. Method In this study, we determined the expression and subcellular localization of Piezo1 in JG cells by qPCR, Western blot, Immunofluorescence (IF), and multiplex immunohistochemistry. Then, a Fluo-4 AM-based calcium-imaging system was used to detect the dynamic changes of intracellular calcium in response to Piezo1 specific agonist Yoda1 and mechanical stress (MS)-induced by perfusion. Next, CRISPR/Cas9 technology was used to generate Piezo1 knockout JG cells to further confirm its contribution. Then, we used RNA-seq experiment to investigate the downstream signaling of Piezo1 in JG cells. Finally, we generated adeno-associated virus (AAV)-mediated kidney-specific Piezo1 knockdown mice to investigate the in vivo effect of Piezo1. Results We found that the mechanosensitive ion channel Piezo1 was co-expressed with renin in JG cells in mouse kidney slides as well as As4.1 cells, a commonly used JG cell line. Activation of Piezo1 by its agonist Yoda1 induced an intracellular calcium increase and reduced the expression of renin in these cells, while knockout of Piezo1 in JG cells abolished the effect of Yoda1. Meanwhile, fluid induced mechanical stress also led to an intracellular calcium increase and renin downregulation in wildtype but not Piezo1 knockout JG cells. Mechanistically, we demonstrated that activation of Piezo1 upregulated the Ptgs2 expression via the calcineurin-NFAT pathway and increased the production of Ptgs2 downstream molecule COX-2 and PGE2 in JG cells, which inhibited cAMP production and reduced renin expression in JG cells. In mice, we demonstrated that activation of Piezo1 significantly downregulated the blood pressure in wildtype but not kidney-specific Piezo1 knockdown mice. Conclusion In summary, these results revealed that activation of Piezo1 could lead to downregulation of the renin expression in vitro and in vivo, subsequently reduction of blood pressure, highlighting its therapeutic potential as a drug target of the renin-angiotensin system.