Expression and role of triggering receptor expressed on myeloid cells 2 in high glucose-treated microglia

Objective To explore the expression of triggering receptor expressed on myeloid cells 2 (TREM2) in high-glucose microglia and to investigate the role of TREM2 in the proliferation, migration and phagocytosis of high-glucose microglia. Methods Microglia cells were divided into control group and high-glucose treatment group(67.5 mmol/L glucose, 24 h). The microglia cells were counted and the expression of Iba1 and TREM2 was detected. TREM2 siRNA was transfected to detect the proliferation and migration of microglia. The amyloid β-peptide (Aβ) with a fluorescent tag was added to observe the phagocytosis of Aβ by microglia. Results Compared to normal microglia, the number of microglia significantly decreased after high-glucose treatment (P＜0.001), while the expression of TREM2 and Iba1 markedly increased (P＜0.001). High glucose and TREM2 did not affect the proliferation of microglia. Compared to the normal group, the migration of microglia significantly decreased after high-glucose treatment (P＜0.05) and TREM2 did not affect the migration ability of high-glucose microglia. Compared to the normal group, the phagocytosis of Aβ by microglia significantly decreased in the high-glucose treated group(P＜0.001). Furthermore, TREM2 knockdown further decreased the phagocytosis of Aβ by high-glucose microglia (P＜0.001). Conclusions The expression of TREM2 in microglia significantly increases after high-glucose treatment, which significantly affects phagocytosis of Aβ by microglia.