Characterization of microglia cells differentiated from induced pluripotent stem cells derived from fibroblasts of alzheimer's disease patients

Alzheimer's disease (AD) is an irreversible and progressive neurodegenerative disease. Besides amyloid beta and tau accumulations, inflammation also contributes to AD pathogenesis. NLRP3 inflammasome activation in microglia is thought to be associated with AD. Animal models of AD do not accurately reflect human pathology. In our study, human induced pluripotent stem cells (iPSCs) were differentiated into microglia, and their potential to be used in NLRP3 pathway related mechanisms in AD was investigated. iPSC cell lines of AD, isogenic (ISO) or control (CTL) genotypes were differentiated into microglia and Flow Cytometry, immunocytochemistry and RT-qPCR were performed. Protein expressions associated with the NLRP3 pathway was investigated by Western Blot. For functional analysis, cytokine release was assessed by ELISA after NLRP3 inflammasome activators (LPS, amyloid beta) and inhibitor (CRID3) treatments. Phagocytosis of pHrodo particles and amyloid beta were evaluated by Flow Cytometry, fluorescence microscopy, and live cell imaging system. iPSCs derived microglia expressed CD43, CD45, CD11b, CD14, TREM2, TMEM119, CX3CR1, P2RY12, IBA1, PU.1, NLRP3, ASC, MyD88 and GSK3beta, detected by immunocytochemistry, Flow Cytometry and Western Blot. IBA1, CD14, CSF1, CX3CR1, TREM2, CCR5, TLR2, TLR4, P2RY12 expressions were shown by RT-qPCR. LPS and amyloid beta stimulation caused IL-1beta and IL-18 release, while CRID3 reversed this effect. Cells were able to phagocytose pHrodo particles and amyloid beta, and AD genotype was slightly more phagocytic than ISO genotype. Our study shows that microglia differentiated from iPSCs are functional and may be an eligible tool to investigate new mechanisms and treatment opportunities in AD