IGF2BP1 Aggravates NLRP3 Inflammasome Activation and Pro-Inflammatory Phenotype in Microglia-like Cells by Promoting...

Cerebral ischemia-reperfusion (I/R) injury is the main cause of early complications and adverse outcomes after treatment such as myocardial infarction and acute ischemic stroke. In this study, we aimed to explore the functions of insulin like growth factor 2 mRNA binding protein 1 (IGF2BP1) and tripartite motif-containing 45 (TRIM45) in neuron injury after cerebral I/R injury. HMC3 cells were exposed to oxygen-glucose deprivation and reoxygenation (OGD/R) to mimic cerebral I/R injury in vitro. Western blot and qRT-PCR were conducted for gene expression. NLR family pyrin domain containing 3 (NLRP3) inflammasome activity was analyzed by western blot. ELISA kits were utilized to determine the concentrations of inflammatory cytokines. Flow cytometry was used to analyze iNOS⁺ cells, CD206⁺ cells and neuron apoptosis. Methylated RNA Immunoprecipitation (meRIP) assay and RIP assay were adopted to analyze the relation between TRIM45 and IGF2BP1. CCK-8 assay and TUNEL assay were adopted for the viability and death of neurons. Mice model of middle cerebral artery occlusion (MCAO) was used to explore the function of IGF2BP2 in cerebral I/R injury. IGF2BP1 level was upregulated in HMC3 cells. IGF2BP1 overexpression promoted NLRP3 inflammasome activation and pro-inflammatory phenotype in OGD/R-stimulated HMC3 cells. Mechanically, IGF2BP1 modulated TRIM45 expression through m6A methylation modification. IGF2BP1 knockdown inhibited NLRP3 inflammasome activation and pro-inflammatory phenotype in OGD/R-stimulated HMC3 cells by m6A methylation modification of TRIM45. Inhibition of IGF2BP1 improved the viability and suppressed the death and apoptosis of neurons in the co-culture system of microglia-like and neurons by regulating TRIM45 expression. Inhibition of IGF2BP1 improved the neurotoxicity of proinflammatory HMC3 cells in co-cultured neurons via reducing the m6A methylation of TRIM45. However, the number of biological replicate samples was relatively small (n = 3) and the results in this study were preliminary study.