Involvement of miR-199a-3p/DDR1 in vascular endothelial cell senescence in diabetes.

Endothelial cell dysfunction is a prominent feature of diabetic cardiovascular complications, and endothelial cell senescence is considered to be an important contributor to endothelial dysfunction. Discoidin domain receptor 1 (DDR1) has been reported to be involved in atherogenesis and cerebral ischemia/reperfusion injury. In this study, we aimed to explore the role of DDR1 in endothelial cell senescence under diabetic conditions and elucidate the underlying mechanisms. A diabetic rat model was established by a single intraperitoneal injection of streptozocin (STZ) (60 mg/kg), which showed an increase in senescence-associated ß-galactosidase (SA-ß-gal) staining signal of thoracic aortic endothelium, impaired vascular structure and function, accompanied by an up-regulation of DDR1. Next, we verified the role of DDR1 in endothelial senescence and the underlying mechanisms in high glucose-treated human umbilical vein endothelial cells (HUVECs). Consistent with the in vivo findings, high glucose induced endothelial senescence, impaired endothelial function and elevated DDR1 expression, accompanied by the elevation of senescence-related genes p53 and p21 expression, and these effects were reversed by DDR1 siRNA. DDR1 has been documented to be a potential target of miR-199a-3p. Here, we found that miR-199a-3p was down-regulated by high glucose in the aorta tissue and HUVECs, while miR-199a-3p mimic significantly suppressed increased endothelial senescence and elevated DDR1 induced by high glucose. In conclusion, our data demonstrated that miR-199a-3p/DDR1/p53/p21 signaling pathway was involved in endothelial senescence under diabetic conditions, and therapeutic targeting DDR1 would be exploited to inhibit endothelial senescence owing to high glucose exposure.

[Effect of lactuside B on the expression of bcl-2 and bax mRNA and their protein in rats' cerebral cortex after cerebral ischemia-reperfusion injury].

This study is to investigate the effect of the major chemical composition in rhizome of Pterocypsela elata, lactuside B, on expression of bcl-2, bax mRNA and their protein in rats' cerebral cortex after cerebral ischemia-reperfusion injury. First, middle cerebral artery ischemia-reperfusion injury model was established, and each group was treated with the corresponding medicines. Animals were separately sacrificed at 24 h and 72 h. The brain infarct volumes were detected by TTC dye, bcl-2 and bax mRNA expression was checked by RT-PCR, and the proteins of bcl-2 and bax were explored by two-step immunohistochemistry in cerebral cortex of rats. Lactuside B can reduce brain infarct volume of cerebral cortex of rats, increase the expression of bcl-2 mRNA and decrease that of bax mRNA. Moreover, the ratio of bcl-2 to bax mRNA is higher in 12.5 and 25 mg kg(-1) dose group, respectively, which is significantly different from that of model group (P < 0.05 or P < 0.01). Generally, either 12.5 or 25 mg kg(-1) dose group is better than positive control medicine nimodipine (P < 0.05 or P < 0.01). In addition, the expression of bcl-2 and bax protein is consistent with their gene expression. Infarct volume and the ratio of bcl-2 to bax mRNA expression are significantly different (P < 0.05 or P < 0.01) between 72 h and 24 h group. The results demonstrated that lactuside B could play a good role in resisting cerebral ischemia by upregulating the expression of bcl-2 mRNA and protein and downregulating that of bax mRNA and protein.