Renal mechanotransduction is an essential regulator of renin

Abstract

The kidneys tightly control the composition of our internal environment to maintain homeostasis in the face of external variability. The regulation of blood volume begins in the kidneys and is essential for vertebrate life in terrestrial environments where salt and water availability are unpredictable1,2. Renin synthesis and release by juxtaglomerular granular cells of the kidney is the rate-limiting step in a hormonal cascade that modulates blood volume, filtration, and salt balance2. Renin is stimulated during hypovolemia and salt deprivation in response to chemical cues released from sympathetic efferent neurons and the macula densa onto the juxtaglomerular granular cells. Renin levels are also proposed to be modulated by mechanical forces elicited by changes in blood volume and/or pressure exerted upon juxtaglomerular cells2-4. However, the identity and significance of the juxtaglomerular mechanotransducer(s) was unknown. We found that the force-gated ion channel PIEZO2 is expressed in juxtaglomerular granular cells and in neighboring mesangial cells. Selective genetic ablation of PIEZO2 dysregulated the renin-angiotensin-aldosterone system by elevating renin, raising systemic blood pressure, inducing glomerular hyperfiltration, and exaggerating the hormonal response to volume depletion. These findings demonstrate that PIEZO2 contributes to renal blood volume sensing and kidney function in vivo.