Renin Cells, From Vascular Development to Blood Pressure Sensing

Abstract

During embryonic and neonatal life, renin cells contribute to the assembly and branching of the intrarenal arterial tree. During kidney arteriolar development renin cells are widely distributed throughout the renal vasculature. As the arterioles mature, renin cells differentiate into smooth muscle cells, pericytes, and mesangial cells. In adult life, renin cells are confined to the tips of the renal arterioles, thus their name juxtaglomerular cells. Juxtaglomerular cells are sensors that release renin to control blood pressure and fluid-electrolyte homeostasis. Three major mechanisms control renin release: (1) β-adrenergic stimulation, (2) macula densa signaling, and (3) the renin baroreceptor, whereby a decrease in arterial pressure leads to increased renin release whereas an increase in pressure results in decrease renin release. Cells from the renin lineage exhibit plasticity in response to hypotension or hypovolemia, whereas relentless, chronic stimulation induces concentric arterial and arteriolar hypertrophy, leading to focal renal ischemia. The renin cell baroreceptor is a nuclear mechanotransducer within the renin cell that transmits external forces to the chromatin to regulate Ren1 gene expression. In addition to mechanotransduction, the pressure sensor of the renin cell may enlist additional molecules and structures including soluble signals and membrane proteins such as gap junctions and ion channels. How these various components integrate their actions to deliver the exact amounts of renin to meet the organism needs is unknown. This review describes the nature and origins of renin cells, their role in kidney vascular development and arteriolar diseases, and the current understanding of the blood pressure sensing mechanism.

Kidney transcriptomics signature of prospective rapid diabetic kidney disease progression

“…For example, the top significant progression-associated transcript in the glomerular subsignature was the kidney-enriched REN which encodes renin and is expressed exclusively by the specialized juxtaglomerular cells. 40 It was strongly down-regulated in the rapid progression cases developing ≥30% UACR increase post-baseline compared to those who did not. The renin-angiotensin-aldosterone system (RAAS) is a well-validated therapeutic target in DKD and CKD, and RAAS inhibitors (RAASi) remain standard of care in DKD and CKD due to their blood pressure and albuminuria lowering effects, thereby preventing eGFR decline.…”