MiR-451 ameliorates red blood cell storage damage and macrophage polarization-mediated transfusion immunity by regulating the AMPK/mTOR signalling pathway.

Red blood cells (RBCs) undergo a series of structural and function-al changes during storage, and miR-451 is crucial for maintaining homeostasis of RBCs. Inflammatory factors and miR-451 expression in whole blood at different storage times were detected by ELISA and qRT-PCR. THP-1 cells were induced into M0 macrophages. Subsequently, miR-451 mimics, miR-451 inhibitor, and activat-ing transcription factor 2 (ATF2) were transfected into the cells, followed by the application of compound C. Macrophages were then polarized to the M1 pheno-type. Macrophage markers were discovered through flow cytometry and Western blot. The adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway protein levels were detected using Western blot. Finally, a mouse model of traumatic hemorrhagic shock was constructed, and blood transfusion and tail vein injection of agomir-451 were performed. The levels of M1 macrophage markers and inflammatory factors were detected by flow cytom-etry and ELISA, respectively. When the human whole blood storage time was 21 d and 35 d, the expression of miR-451 decreased, and the proinflammatory factor contents increased. When miR-451 was overexpressed, proinflammatory cytokines and M1 macrophage markers’ expression in THP-1 cells were reduced, p-AMPK level was increased, and p-mTOR level was decreased. After overexpression of ATF2 or compound C, proinflammatory factors and M1 macrophage markers in THP-1 cellsincreased, and p-AMPK and p-mTOR expression reversed. Overexpression of miR-451 also inhibited macrophage M1 polarization and inflammation in shock mice. miR-451 inhibits ATF2-regulated AMPK/mTOR pathway, inhibits macrophage M1 polarization and inflammation, and improves RBC storage damage.