miR-155 activates the NLRP3 inflammasome by regulating the MEK/ERK/NF-κB pathway in carotid atherosclerotic plaques in ApoE-/- mice.

Atherosclerosis is an inflammatory disease. The NLRP3 inflammasome and miR-155 are significant components of inflammation and atherosclerosis. The aim of this research was to explore the possible mechanism by which miR-155 mediates the formation of carotid atherosclerotic plaques via the NLRP3 inflammasome. Fifty 6-week-old male ApoE-/- mice were randomly divided into 5 groups. They are the blank group, the negative control (NC) group, the miR-155 mimic group, the miR-155 inhibitor group, and the miR-155 mimic and ERK inhibitor group. The blood lipid levels were measured by the enzyme method Oil red O, HE, and immunohistochemical staining were used to observe the degree of carotid plaque formation. PCR was used to measure the expression of miR-155. The blood lipid levels were measured by the enzyme method. Western blotting was used to measure the expression of NLRP3 inflammasome-related proteins, interleukin-1β, interleukin-18, and MEK/ERK/NF-κB signaling pathway-related proteins. Compared with those of the NC group, the expression of miR-155 in the miR-155 mimic group increased significantly (P < 0.05), the degree of carotid plaque formation increased, the plasma levels of TC and LDL also increased significantly (P < 0.05); the expression levels of NLRP3 inflammasome-related proteins, interleukin-1β, interleukin-18, and MEK/ERK/NF-κB signaling pathway-related proteins were also significantly increased. Injection of ERK inhibitors into miR-155 mimic mice reduced the expression levels of p-NF-κB, NLRP3 inflammasome-related proteins, and inflammatory cytokines. In conclusion, miR-155 can promote the formation of atherosclerotic plaque in ApoE-/- mice, which may be achieved by regulating the MEK/ERK/NF-κB pathway to activate the NLRP3 inflammasome. HIGHLIGHTS: • In ApoE-/- mice, miR-155 promotes atherosclerotic plaque formation. • The NLRP3 inflammasome has an important role in the inflammatory process of atherosclerosis. • miR-155 activates the NLRP3 inflammasome by regulating the MEK/ERK/NF-κB pathway in carotid atherosclerotic plaques of ApoE-/- mice.