Abstract
Purpose :
Diabetic retinopathy (DR) remains a leading cause of severe visual impairment worldwide, particularly in the working-age population. Dysregulation of microglial activation in DR contributes to neurodegeneration, vascular permeability, and pathological neovascularization. Despite the established involvement of innate immune activation in DR pathogenesis, the polarity changes in retinal microglia under ischemic conditions and their role in disease progression remain inadequately understood. In this investigation, we explored the polarity changes in active microglia under ischemic conditions utilizing human induced pluripotent stem cell (hiPSC)-derived microglial cells (hiMG).
Methods :
hiMGs were differentiated from hiPSCs via embryoid body formation following established protocols. The hiMGs were cultured under conditions relevant to DR, with stimulation using dimethyloxalylglycine (DMOG) to induce hypoxia, lipopolysaccharide (LPS) to activate innate immunity, and co-stimulation with DMOG and LPS. Comprehensive gene expression analyses, including RNAseq analysis, transcriptome analysis, and qPCR, were employed to validate the characterization and polarization of hiMGs.
Results :
Principal component analysis (PCA) plot analysis revealed distinct polarity changes in hiMGs with specific gene expression profiles following DMOG, LPS, and DMOG-LPS stimulations. LPS stimulation upregulated 912 genes, while DMOG stimulation upregulated 216 genes. Gene Ontology (GO) analysis indicated that DMOG stimulation activated hypoxic response, whereas LPS stimulation activated TLR4-mediated innate immune response. DMOG-LPS co-stimulation significantly enhanced the expression of VEGFA and PTGS2 compared to LPS or DMOG stimulation alone. GO analysis of the upregulated genes showed a significant association with angiogenesis, cell migration, and fibroblast proliferation (p < 0.0001).
Conclusions:
Conclusions :
Our findings suggest that the immune response under hypoxic conditions accelerates polarity changes in retinal microglia. These changes may play a pivotal role in pathological conditions such as neovascularization, fibroproliferation, and neurodegeneration.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.