| Summary: | 碩士 === 高雄醫學大學 === 藥理學研究所 === 97 === Endothelin-1 (ET-1) has been implicated in cardiac pathology, such as the progression from cardiac hypertrophy to failure. KMUP-1 is a unique xanthine and piperazine derivative, combining the sGC stimulation, K+ channels opening and particularly phosphodiesterase type 5（PDE-5）inhibition activities in one molecule.
The purpose of this study was to determine the efficacy and the possible mechanism of action of KMUP-1 on the ET-1-induced cardiac hypertrophy in cardiomyocytes. When cardiac myoblasts (H9c2 cells) were treated with ET-1 (100 nM) for 4 days, hypertrophy was observed, as assessed by the measurement of cell surface area, and this effect was strongly prevented by KMUP-1. Western blot analysis showed that KMUP-1 decreased ET-1-induced phosphorylation of ERK1/2, p38 and Akt/GSK3?? and also decreased calcineurin/NFAT and RhoA/Rock expression. KMUP-1 also enhanced HO-1 protein expression, and previous study have shown that HO-1 can inhibit mitogen-activated protein kinase (MAPK), calcineurin/NFAT signaling and hypertrophy in cardiac myocytes. Electrophoretic mobility shift assay showed that KMUP-1 inhibited ET-1-induced activator protein-1 (AP-1) DNA binding activities. In addition, incubation of H9c2 cells with KMUP-1 significantly decreased the intracellular peroxide level induced by ET-1 according to fluorescent microscopic observation using DCHF-DA as a fluorescent substrate. We further examined the effect of KMUP-1 on ET-1-induced increase oxygen consumption as an index of ROS generation in H9c2 cells.
In conclusion, these findings suggest that KMUP-1 protects ET-1-induced hypertrophy in H9c2 cells by blocking phosphorylation of ERK1/2, p38, Akt/GSK3β, calcineurin/NFAT and RhoA/Rock activation, enhancing HO-1 protein expression and decreasing ROS generation.
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