Circ_0008285 regulates macrophage polarization through miR-375/MAPK14 axis in sepsis-induced acute lung injury

Acute lung injury (ALI) induced by sepsis is a serious life-threatening disease, one of its characteristics is the polarization of macrophages. Circ_0008285 has been found to be associated with various diseases. In this study, we detected the regulatory role and mechanism of circ_0008285 in sepsis-induced ALI. RAW264.7 cells treated with LPS and C57BL/6 male mice were used to construct in vitro and in vivo models, respectively. Through A series of experiments such as qRT-PCR, Western blot, CCK-8, flow cytometry, dual-luciferase reporter experiment, HE staining and TUNEL staining, the role of circ_0008285 in sepsis-induced ALI was explored. In LPS-induced RAW264.7 cell, circ_0008285 and MAPK14 were over-expressed, but miR-375 was low-expressed compared with control. The levels of IL-1β, IL-6, TNF-α, iNOS and CD86 were reduced, but CD206 and Arg1 expression were enhanced both in vitro and in vivo after knockdown of circ_0008285. In TC-1 cell co-cultured with LPS+sh-circ_0008285 cells, the viability was increased and the apoptosis level was decreased compared with LPS+sh-NC. Circ_0008285 was the sponge of miR-375, and MAPK14 was the downstream target of miR-375. The injury score, W/D ratio, MPO level and apoptosis level in lung tissue were decreased after knockdown of circ_0008285. Moreover, the total protein, neutrophils and macrophages in BALF were increased. Collectively, this study identified that circ_0008285 could sponge miR-375 to influence MAPK14 expression, and then regulate macrophage polarization of sepsis-induced ALI, which provided new insights for the treatment of sepsis-induced ALI.