Inhibition of miR-188-5p Suppresses Progression of Experimental Abdominal Aortic Aneurysms

Abstract

Abdominal aortic aneurysm (AAA) is an aging-related degenerative disease. miR-188-5p was reported to induce cell senescence and play a key role in aging-related disease. Therefore, in this study, we investigated miR-188-5p expression during progression in experimental AAAs. Furthermore, we investigated whether inhibition of miR-188-5p could suppress AAA progression. Experimental AAAs were created in 9-12-week-old male C57BL/6J mice by transient intra-aortic infusion of porcine pancreatic elastase. Expression of miR-188-5p levels were assessed in aneurysmal and control aortae during the progression of aneurysm. For inhibition experiment, miR-188 inhibiting group mice were injected with AAV2-miR188-5p sponge through tail vein and control group mice were injected with AAV2-CMV-GFP. Influences on experimental AAA progression were assessed by measurements of aortic diameter and histopathologic analysis at sacrifice. Meanwhile, immunohistochemistry and fluorescence in situ hybridization were used to determine the inflammatory cells infiltration and colocalization of miR-188-5p in aortic sections. Expression of miR-188-5p is upregulated during progression of AAA. Importantly, miR-188-5p inhibition treatment prevented enlargement of experimental aneurysms. Meanwhile, miR-188-5p inhibition regimens attenuated medial elastin degradation, smooth muscle cell depletion, and mural angiogenesis and the accumulation of macrophages, T cells, and angiogenesis. Furthermore, colocalization of miR188-5p with CD68 and CD3 was observed, which suggest miR-188-5p was expressed mainly in infiltrated macrophages and T cells. Expression of miR-188-5p is increased in experimental AAAs. Treatment with miR-188-5p inhibition limits experimental AAA progression, with histologic evidence of reduced neovessels and attenuated mural leukocyte infiltration. These findings underscore the potential significance of miR-188-5p in aneurysm pathogenesis and as a target for suppression of AAA disease.