Regulating distal nephron functions and salt sensitivity.

This review highlights the molecular basis of salt sensitivity in hypertension, with a focus on the regulation of sodium transport in the distal nephron. Sodium reabsorption in this region is often linked to the actions of aldosterone, although in recent years numerous findings have been reported on the aldosterone-independent pathway of acquiring salt sensitivity by potassium deficiency or potassium loading. The key to this discussion is the interplay, through extracellular potassium concentration, between the first part of the tubules expressing the Na⁺-Cl^- cotransporter (NCC) and the second part expressing the epithelial Na⁺ channel (ENaC). The molecular pathways such as with-no-lysine 1 (WNK)-STE20/SPS1-related proline-alanine-rich kinase (SPAK)/oxidative stress-responsive kinase 1 (OSR1) signaling, Kelch-like family member 3 (KLHL3)-cullin 3 (CUL3) complex, protein phosphatases, and mechanistic target of rapamycin complex 2 (mTORC2)-Nedd4L pathway are described as the mechanism by which salt sensitivity on blood pressure is acquired in response to changes in physiological conditions including potassium depletion or loading. This review highlights the potential for targeting these molecular pathways to develop novel therapeutic strategies for the treatment of salt-sensitive hypertension, the mechanism of which remains to be elucidated.