Angiotensin II Regulates the ROMK Channel in the Renal Distal Convoluted Tubule via the MAPK-dependent Pathway

Abstract

Background: Hypertension serves as a significant risk factor for various cardiovascular and renal diseases, necessitating a deeper understanding of its pathogenesis, as well as the identification of potential therapeutic targets. This study aims to investigate the molecular mechanisms underlying hypertension, specifically focusing on the regulation of renal outer medullary potassium (ROMK) channels by the mitogen-activated protein kinase (MAPK) signaling pathway and its impact on water-electrolyte metabolism. Methods: A mouse hypertension model was constructed, and mouse primary renal tubular epithelial cells were stimulated with Angiotensin II (AngII). Differential gene expression, key signaling pathways, and molecules were analyzed utilizing bioinformatics approaches. Furthermore, Western blot and quantitative polymerase chain reaction (qPCR) analyses were used to assess the expression of the ROMK channel both at mRNA and protein levels as well as the signaling molecule MAPK. Additionally, the MAPK inhibitors were applied to further elucidate the involvement of this signaling pathway in hypertension. Results: The contents of sodium, potassium, chloride in mouse blood pressure (BP) and urine were detected. A gradual increase was observed in both mRNA and protein levels of ROMK following AngII stimulation, reaching a peak on day 7. Furthermore, in vitro experiments revealed that following AngII stimulation, ROMK protein and mRNA expression levels were significantly increased compared to the control cells. Similarly, the expression levels of Phospholipase C (PLC), Protein kinase C (PKC), and MAPK proteins were significantly higher. Furthermore, Western blot analysis revealed a significant reduction in the levels of ROMK in renal tubular epithelial cells. Meanwhile, the BP decreased, and the amount of sodium and potassium ions decreased. Conclusion: The study demonstrates the potential significance of AngII regulating the upregulation of ROMK channels through MAPK-dependent pathway to promote potassium excretion and affect water-salt balance, leading to the development of hypertension.