Regulatory effect of microRNA-126 on macrophage proliferation caused by high glucose stimulation

Abstract

Objective: To explore the effects of microRNA-126 (miR-126) on the proliferation of human myeloid leukemia mononuclear cells (THP-1)-derived macrophages in high glucose environment and the regulatory role of miR-126 in periodontitis with diabetes. Methods: THP-1 cells were cultured in vitro and 5 μg/L phorbol-12-myristate-13-acetate was applied to induce THP-1 cells differentiating into macrophages for 48 h in low glucose culture medium (5.5 mmol/L). THP-1-derived macrophages were then cultured with low glucose, medium glucose (15 mmol/L) or high glucose (25 mmol/L) media respectively. The proliferation of THP-1-derived macrophages was detected by cell counting kit-8 (CCK-8) method and the expressions of miR-126 and proliferation-associated factors were detected by quantitative real time PCR (qRT-PCR). The miR-126 mimic or inhibitor was transfected into THP-1-derived macrophages for 72 h. The proliferation of cells was detected by CCK-8 method and the expressions of miR-126 or proliferation-associated factors were detected by qRT-PCR. Results: Increasing glucose concentration decreased the proliferation of THP-1-derived macrophages (day 7, A values in low, medium and high glucose groups were 0.369±0.014, 0.214±0.009 and 0.200±0.010, respectively, P<0.01) as well as the survival rate (P<0.05), promoted the expression of miR-126, B-cell lymphoma-2 (Bcl-2)-associated X protein (BAX) and caspase-3 (P<0.05), and suppressed Bcl-2, phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2) expression (P<0.05). After the miR-126 mimic was transfected in cells in low glucose medium for 72 h, compared with negative control (1.005±0.118), the expression of miR-126 significantly increased (2 980.227±170.431, P<0.05), and the proliferation of THP-1 derived macrophages decreased (negative control: 1.816±0.013, mimic group: 1.310±0.048, P<0.01), the level of BAX and caspase-3 significantly increased (P<0.01, P<0.05), PIK3R2 and Bcl-2 significantly decreased (P<0.05, P<0.01). After the miR-126 inhibitor was transfected in cells cultured in high glucose medium for 72 h, compared with negative control (0.723±0.133), the proliferation of inhibitor group increased (0.984±0.049, P<0.05), the level of BAX and caspase-3 significantly decreased (P<0.01, P<0.05), PIK3R2 and Bcl-2 significantly increased (P<0.01, P<0.05). Conclusions: High glucose condition can inhibit the proliferation of THP-1-derived macrophages and increase the expression of miR-126. MiR-126 can inhibit the proliferation of THP-1-derived macrophages in high glucose environment through up-regulating the expression of BAX and caspase-3 and down-regulating the expression of PIK3R2 and Bcl-2.