CircCBFB-mediated miR-28-5p facilitates abdominal aortic aneurysm via LYPD3 and GRIA4.

Abdominal aortic aneurysm (AAA) is featured by the growth impediment and apoptosis surge of VSMCs (vascular smooth muscle cells). MicroRNAs (miRNAs) are suggested to affect cellular behaviors including cell growth and apoptosis. This study concentrated on unraveling the emerging role of miR-28-5p in abdominal aortic aneurysm. Previously, miR-28-5p was reported to be highly expressed in AAA. Functional assays were utilized to determine the role of miR-28-5p in VSMC apoptosis. To narrow down the downstream mRNAs, bioinformatics methods were utilized. The interaction between miR-28-5p and GRIA4 (glutamate ionotropic receptor AMPA type subunit 4) or LYPD3 (LY6/PLAUR domain containing 3) was explored. Candidate circRNAs (circular RNAs) of miR-28-5p were identified. Rescue analyses validated function of circCBFB (core-binding factor subunit beta)/miR-28-5p/GRIA4/LYPD3 axis in VSMC apoptosis and growth. MiR-28-5p acted as an apoptosis driver while circCBFB, GRIA4 and LYPD3 exerted anti-apoptosis effects in VSMCs. Mechanically, GRIA4 and LYPD3 were suppressed by miR-28-5p. Moreover, circCBFB served as a sponge of miR-28-5p, releasing GRIA4 and LYPD3 from miR-28-5p suppression. Functionally, GRIA4, LYPD3 and miR-28-5p were required in circCBFB-mediated VSMC apoptosis. This work unveiled an innovative axis of circCBFB/miR-28-5p/GRIA4/LYPD3 in VSMC apoptosis, exerting its potential in providing new thoughts in AAA management.