M1 Macrophage-Derived Exosome LncRNA PVT1 Promotes Inflammation and Pyroptosis of Vascular Smooth Muscle Cells in Abdominal Aortic Aneurysm by Inhibiting miR-186-5p and Regulating HMGB1.

Abdominal aortic aneurysm (AAA) is a chronic vascular degenerative disease. Vascular smooth muscle cells (VSMCs) are essential for maintaining the integrity of healthy blood vessels. Macrophages play an important role in the inflammatory process of AAA. However, the effect of macrophage-derived exosome LncRNA PVT1 on VSMCs is unclear. Exosomes from M1 macrophages (M1φ-exos) were isolated and identified. The expression of LncRNA PVT1 in M1φ-exos was determined. AAA cell model was constructed by treating VSMCs with Ang-II. AAA cell model was treated with M1φ exosomes transfected with si-LncRNA PVT1 (M1φsi-LncRNA PVT1 -exo). VSMCs were transfected with miR-186-5p mimic and oe-HMGB1. Cell viability was detected by CCK-8. The accumulation of LDH was detected by ELISA. Western blot was used to detect the expression of HMGB1, inflammatory factors (IL-6, TNF-α and IL-1β) and pyroptosis-related proteins (GSDMD, N-GSDMD, ASC, NLRP3, Caspase-1 and Cleaved-Capase-1). Cell pyroptosis rate was detected by flow cytometry. At the same time, the targeting relationship between miR-186-5p and LncRNA PVT1 and HMGB1 was verified by double fluorescein experiment. Exosomes from M1φ were successfully extracted. The expression of LncRNA PVT1 in M1φ-exos was significantly increased. M1φ-exo promotes inflammation and pyroptosis of VSMCs. M1φsi-LncRNA PVT1 -exos inhibited the inflammation and pyroptosis of VSMCs. LncRNA PVT1 can sponge miR-186-5p mimic to regulate HMGB1 expression. MiR-186-5p mimic further inhibited inflammation and pyroptosis induced by M1φsi-LncRNA PVT1 -exos. However, oe-HMGB1 could inhibit the reversal effect of miR-186-5p mimic. LncRNA PVT1 in exosomes secreted by M1φ can regulate HMGB1 by acting as ceRNA on sponge miR-186-5p, thereby promoting cell inflammatory and pyroptosis and accelerating AAA progression.