Prorenin induces vascular smooth muscle cell proliferation and hypertrophy via epidermal growth factor receptor-mediated extracellular signal-regulated kinase and Akt activation pathway
2011
BACKGROUND: It is widely acknowledged that the (pro)renin receptor mediates angiotensin (Ang) II-dependent and Ang II-independent effects of prorenin. METHOD: We examined the effect of prorenin on vascular smooth muscle cell (VSMC) signal transduction, proliferation, and hypertrophy. RESULTS: Recombinant rat prorenin dose-dependently increased extracellular signal-regulated kinase (ERK) 1/2 and Akt phosphorylation in rat VSMCs. Prorenin also significantly increased cell number, and [H]-thymidine and [H]-leucine incorporation, which were attenuated by pretreatment with inhibitors for ERK kinase and phosphatidylinositol 3 kinase. Prorenin was also found to stimulate epidermal growth factor (EGF) receptor and Src phosphorylation. Pretreatment of VSMCs with an EGF receptor tyrosine kinase inhibitor and a Src inhibitor significantly attenuated the prorenin-induced increase in ERK 1/2 and Akt phosphorylation, as well as DNA and protein synthesis. Prorenin-induced phosphorylation of the EGF receptor, ERK 1/2, and Akt, as well as DNA and protein synthesis were all blocked by (pro)renin receptor siRNA, but not by an Ang II type 1 receptor blocker, candesartan, nor an Ang-converting enzyme inhibitor, captopril. CONCLUSION: These results reveal that prorenin directly stimulates VSMC proliferative and hypertrophic changes, dependent on the (pro)renin receptor, independent of Ang II. Furthermore, EGF receptor-mediated ERK 1/2 and Akt activation contributes to prorenin-dependent proliferative and hypertrophic effects in VSMCs.
Keywords:
- Internal medicine
- Medicine
- Protein kinase B
- Vascular smooth muscle
- Endocrinology
- Cell growth
- Epidermal growth factor receptor
- Extracellular signal-regulated kinases
- Growth factor receptor inhibitor
- Muscle hypertrophy
- Growth factor receptor
- Proto-oncogene tyrosine-protein kinase Src
- Kinase
- MAPK/ERK pathway
- Epidermal growth factor
- Signal transduction
- Correction
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