Study on the role of miR-186-5p in GC-1 cell cycle arrest induced by titanium dioxide nanoparticles

Abstract

Titanium dioxide nanoparticles (TiO2 NPs) downregulated the expression of C-X-C motif chemokine ligand 13 (CXCL13) to induce spermatogonium cell cycle arrest at the G0/G1 phase, but the specific upstream regulatory mechanisms are not completely clarified. The purpose of this study was to investigate whether TiO2 NPs induce cycle arrest of spermatogonium through miR-186-5p or miR-122-5p mediated regulation of CXCL13. The mouse spermatogonia cell line (GC-1) cells were treated with different concentrations of TiO2 NPs (0, 10, 20, 30, and 40 μg/mL) for 24 hours to determine miR-186-5p, miR-122-5p and CXCL13 levels, cell cycle and key protein expressions of cell cycle. miR-186-5p and miR-122-5p inhibitors were used to verify the role of miR-186-5p and miR-122-5p in cell cycle arrest induced by TiO2 NPs. TiO2 NPs increased the level of miR-186-5p, decreased the levels of CXCL13. TiO2 NPs also reduced the levels of Cyclin E1, Cyclin D1, CDK2, and CDK4, increased the levels of p21, and elevated the percentage of G0/G1 phase cells. Inhibition of miR-186-5p reversed TiO2 NP-induced reductions in CXCL13 expression, restored the key cell cycle protein levels, and alleviated cell cycle arrest in GC-1 cells. Collectively, TiO2 NPs increased miR-186-5p expression in GC-1 cells, which down-regulated the CXCL13 level, induced aberrant expression of cell cycle-related proteins, ultimately induced the cell cycle arrest in G0/G1 phase, whereas miR-122-5p showed no effect in this process. This mechanistic insight advances our understanding of TiO2 NP reproductive toxicity and identifies potential intervention targets.