Mechanisms underlying the vasorelaxant effects induced by 3-(4-hydroxy-3-methoxyphenyl)propionic acid and its conjugates in HUVECs

Abstract

【Purpose】 This study aims to investigate the potential physiological roles of 3-(4-hydroxy-3-methoxyphenyl) propionic acid (HMPA), and its metabolic forms, focusing on their ability to produce nitric oxide (NO), and their underlying molecular mechanisms in human umbilical vein endothelial cells (HUVECs).

【Methods】 The NO assay was performed by fluorometric NO assay kit ((E_x/E_m: 355/460 nm). Cellular uptake and transport characteristics were investigated by using LC-QTOF/MS. Intracellular Ca²⁺ was detected with Calcium kit II-Fluo 4 by using Flex Station III multimode microplate reader (E_x/E_m: 485/525 nm).

【Results】 HMPA and its conjugates (0.1 µM) stimulated NO production in HUVECs at 1 h. Transporter inhibitors for MCTs and OATPs significantly decreased the cellular uptake of all metabolites, while GLUT inhibitor only significantly reduced those of HMPA-GlcA and HMPA-S. HMPA and its conjugates significantly increased [Ca²⁺]_i, IP₃R inhibitor significantly abolished HMPA-GlcA-induced [Ca²⁺]_i increase indicating glucuronidated HMPA promoted calcium release from the ER via the stimulation of IP₃R receptor in HUVECs.