RESUMEN
The present study aimed to investigate the impact of losartan and angiotensin II (AngII) on the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1), secreted by rat vascular smooth muscle cells (VSMCs). Rat VSMCs were isolated and cultured in different concentrations of AngII and losartan for 24 h and western blot analysis and quantitative polymerase chain reaction were performed to observe the subsequent impact on the gene and protein expression of MMP-9 and TIMP-1. AngII was shown to promote the protein and gene expression of MMP-9 in VSMCs in a concentration-dependent manner. No effect was observed on the expression of TIMP-1, therefore, an increase in the MMP-9/TIMP-1 ratio was observed. Losartan was shown to be able to inhibit MMP-9 protein and gene expression in a concentration-dependent manner, whilst promoting an increase in TIMP-1 expression, thus decreasing the ratio of MMP-9/TIMP-1. The combined action of losartan and AngII resulted in the same directional changes in MMP-9 and TIMP-1 expression as observed for losartan alone. The comparison of AngII, losartan and the combinatory effect on the expression of MMP-9 and TIMP-1 in VSMCs indicated that losartan inhibited the effects of AngII, therefore reducing the MMP-9/TIMP-1 ratio, which may contribute to the molecular mechanism of losartan in preventing atherosclerosis. In atherosclerosis, the development of the extracellular matrix of plaque is closely correlated with the evolution of AS. The balance between MMPs and TIMPs is important in maintaining the dynamic equilibrium between the ECM, and the renin-angiotensin-aldosterone system, which is involved in the pathologenesis of AS, and in which AngII has a central role.
Asunto(s)
Angiotensina II/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Losartán/farmacología , Metaloproteinasa 9 de la Matriz/genética , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Inhibidor Tisular de Metaloproteinasa-1/genética , Animales , Células Cultivadas , Metaloproteinasa 9 de la Matriz/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Inhibidor Tisular de Metaloproteinasa-1/metabolismoRESUMEN
OBJECTIVE: To investigate the effects of the potent immunosuppressive agent cyclosporin A (CsA) on the proliferation of human endothelial progenitor cells (EPCs) and endothelial nitric oxide synthase (eNOS) expression in EPCs. METHODS AND RESULTS: The EPCs were obtained from cultured mononuclear cells, which were isolated from the peripheral blood of healthy adults, and stimulated with CsA (10 microg/mL) in the presence or absence of either vascular endothelial growth factor (VEGF; 50 ng/mL) or L-arginine (1 mM). To explore the effect of different concentrations of CsA alone on EPC proliferation, some cells were treated with CsA in a series of final concentrations ranging from 0 to 10 microg/mL. Cell proliferation and apoptosis were determined, respectively, by the Cell Counting Kit-8 assay and terminal deoxynucleotidyl transferase-mediated nick end labeling staining. The expression of eNOS was assayed by reverse transcription-polymerase chain reaction analysis while nitric oxide (NO) generation was detected using the Griess method. The effects of CsA on EPC proliferation, apoptosis, and eNOS/NO production were dose dependent in the concentration ranging from 0.1 microg/mL to 10 microg/mL. Treatment with VEGF (50 ng/mL) significantly promoted EPC proliferation and eNOS/NO production, which were completely abrogated by pre-incubation with CsA (10 microg/mL). The supplement of L-arginine (1 mM) promoted NO production that enhanced EPC proliferation and attenuated the effect of CsA on EPC proliferation and apoptosis. CONCLUSION: CsA significantly inhibited proliferation, eNOS mRNA expression and NO production of human EPCs, in a dose-dependent manner.