Platelet-derived growth factor receptor-β in myocyte was upregulated by angiotensin II

Abstract

To observe the regulatioon of platelet-derived growth factor (PDGF) receptor-β in myocyte stimulated by angiotensin II (AngII) at both integrated and cellular levels and reveal the signal transduction mechanism in cell, two kidneys, one clip (2K1C) renal hypertension were performed by placing a sliver clip around the left renal artery. Blood pressure and the ratio of left ventricular weight to body weight were measured at 4 and 8 weeks after operation. The content of AngII in heart was detected by radioimmunology assay; the protein level of PDGF receptor-β in heart was measured by Western blot analysis. The alteration of PDGF receptor-β stimulated by AngII and several inhibitors was observed on cultured neonatal rat ventricular myocyte (NRVM). The content of AngII in heart of 2K1C renal hypertensive rat at 4 and 8 weeks after operation was increased. Compared with sham group, 4 and 8 weeks after operation, PDGF receptor-β in heart of 2K1C group was upregulated by 100.3% and 127.1% (P< 0.05), respectively. This upregulation could be inhibited by captopril. For cultured myocyte, PDGF receptor-β was increased by 47.1% after being stimulated by AngII and this upregulation could be inhibited by losartan which was an inhibitor of AT1 receptor. PLC inhibitor (U73122) and MEK inhibitor (PD98059) could partly inhibit PDGF receptor-β upregulation induced by AngII. These results suggested that AngII could upregulate PDGF receptor-β in myocyte by its AT1 receptor and this effect was at least partly dependent on PLC and extracellular signal-regulated kinase (ERK).