Alteration of discoidin domain receptor-2 expression: possible role in peroxynitrite-induced apoptosis in human cerebral vascular smooth muscle cells

Peroxynitrite(ONOO-), a product of nitric oxide and superoxide anion interaction, is a powerful and versatile oxidant. In this work, the human cerebral vascular smooth muscle cells (HCVSMCs) were cultured in vitro and subjected to different concentrations of ONOO-. Cell viability and morphological changes were measured by methylthiazoletetrazolium (MTT) assay and Ho33342/PI double staining respectively. The apoptotic rate was assessed by flow cytometry. The alterations in the expression of DDR2 at both mRNA and protein levels were examined by real-time PCR and Western-blot simultaneously. Direct exposure of HCVSMCs to ONOO- was able to inhibit the cell proliferation, which was further revealed via the apoptotic pathway. ONOO- exerted a dual-effect on DDR2 expression at both mRNA and protein levels that depended on the concentrations of ONOO-. Our results demonstrate for the first time that DDR2 gene may play an important role in ONOO--induced apoptosis in HCVSMCs.