Molecular mechanism of p-Coumaric acid in the regulation of AQP2 function through the activation of calcium-sensing receptor signaling
摘要
The hormone vasopressin (AVP) controls renal water reabsorption by modulating the expression and trafficking of the water channel aquaporin-2 (AQP2) through the activation of the cAMP/PKA signal transduction pathway. Previous studies revealed that Olive Leaf Extract (OLE) counteracts the vasopressin-dependent AQP2 functions by stimulating the calcium-sensing receptor (CaSR). Here, the biological activities of p-Coumaric acid, a selective polyphenol in OLE, were investigated. Stimulation of renal collecting duct MCD4 cells with p-Coumaric acid at a concentration of 1 nM caused a significant intracellular calcium release. NPS-2143, a selective CaSR antagonist, abolished this increase. Molecular docking analysis revealed that p-Coumaric acid can form binding interactions with the binding pocket of Tecalcet, a known CaSR activator, likely suggesting that p-Coumaric acid may stimulate the CaSR. Confocal analysis and immunoblotting experiments showed that p-Coumaric acid impaired the DDAVP-dependent membrane expression of AQP2 and the consequent increase of the osmotic water permeability (Pf). Additionally,