Quantification of Target Proteins Regulated by Micrornas in Abdominal Aortic Aneurysm Tissue

Abstract

Introduction: microRNAs (miRNAs) are small non-coding RNA molecules that regulate protein expression. In a previous study we identified a set of miRNAs dysregulated in tissue of Abdominal Aortic Aneurysm (AAA) patients followed by an in silico analysis of their potential targets. In the present study our aim was to confirm if some of these protein targets were also dysregulated in AAA tissue, thus revealing novel insights into the mechanisms of AAA development. Methods: We obtained abdominal aortic tissue from patients undergoing AAA open repair surgery (N=11) and from healthy organ donors (N=7). Proteins were extracted with the miRVANA PARIS® kit (Ambion). Five proteins were selected to be quantified by Western Blot using specific antibodies and their expression was normalized against that of α-tubulin. Expression values were compared between groups with a student t test. Correlation of proteins and miRNAs expression was analyzed with Pearson correlation test. Results: Increased levels of thrombospondin-2 (THBS2) were observed in AAA tissue compared with healthy tissue (10.7±2.7 vs 2.8±0.7, relative expression) (P=0.04). Moreover, the expression levels of THBS2 negatively correlated with one of their potentially regulator miRNAs, miR-195-5p (r2=0.442, ρ=-0.665, P=0.0026). Two other proteins, LIM and SH3 domain protein 1 (LASP1) and Human Integrin alpha V (ITGAV), were also slightly overexpressed in AAA patients but without significant results. No correlation with their potentially regulator miRNAs were found. Conclusion: We have confirmed the overexpression of a potential target of a dysregulated miRNA in AAA tissue. Together with other studies, our results highlight the regulatory role of miR-195-5p in AAA, however further studies need to be done to elucidate its role in the pathology. In that sense we propose THBS2, a potential target of miRNA-195-5p, as a possible mediator in AAA. THBS2 has been previously related to the regulation of angiogenesis (1) and vascular smooth muscle cells proliferation (2) thus its involvement in vascular pathologies is highly plausible. Disclosure: Nothing to disclose