Chronic central miR-29b antagonism alleviates angiotensin II-induced hypertension and vascular endothelial dysfunction

Dysregulation of miR-29 has been revealed in multiple diseases, but its role in the development of hypertension and vascular endothelial dysfunction has not been defined. Here, we found that, compared with the wild-type (WT) Wistar rats, miR-29b was robustly upregulated in spontaneously hypertensive rats (SHRs), while CTRP6 was distinctly downregulated. There were two miRNA-responding-elements (MREs) for miR-29 in the 3′-UTR of CTRP6 mRNA, and the luciferase activity assay revealed that miR-29b directly targeted CTRP6 mRNA. Intraventricular injection was applied to deliver the miR-29b mimic or miR-29b inhibitor (4 mg/kg) into SHRs once two weeks from 10th week. Downregulation of miR-29b could increase serum CTRP6 content in SHRs, decrease the arterial systolic pressure, reduce serum concentrations of Ang II and ET-1, and enhance serum NO content. Meanwhile, we demonstrated that inhibition of miR-29b increased the phosphorylation of ERK1/2 to activate PPARγ, an inducer of Ang II. Finally, miR-29b expression was manipulated in, and CTRP6 recombinant protein was applied to incubate with the primary aortic endothelial cells. Inhibition of miR-29b increased CTRP6 expression, improved cell proliferation and migration, suppressed secretion of Ang II and ET-1, and decreased ROS accumulation and LDH release, displaying a similar effect to the CTRP6 recombinant protein. Moreover, the CTRP6 recombinant protein could antagonize the suppressive effect of miR-29b on activation of the ERK/PPARγ axis and function of aortic endothelial cells. In conclusion, miR-29b antagonism can alleviate Ang II-induced hypertension and vascular endothelial dysfunction through activating the CTRP6/ERK/PPARγ axis.