BACKGROUND: This study aims to investigate the role of miR-646 in hypoxia conditions in human periodontal ligament cells (hPDLCs), exploring the effect of hypoxia on hPDLCs proliferation and apoptosis. In addition, this study aimed to explore the potential mechanism of miR-646/IGF-1 signaling in hPDLCs in hypoxia conditions.

MATERIAL AND METHODS: hPDLCs (fifth passage) cultured by the tissue culture method were randomly assigned to the severe hypoxia (1% O2) group, the slight hypoxia (5% O2) group or the control (21% O2) group. Then reverse transcription quantitative real-time polymerase chain reaction and western blot analysis were used to detect the mRNA and protein expression of miR-646 and IGF-1. hPDLCs infected with lentivirus (LV)-pre-miR-646 or LV-anti-mR-646, and negative controls were cultured. MTT assay, caspase-3 ELISA assay, and wound healing assay were performed to evaluate how miR-646 was influenced by hypoxia. In addition, the relationship between miR-646 and IGF-1 was explored.

RESULTS: The expression of miR-646 was downregulated and IGF-1 was upregulated in hypoxia conditions. MiR-646 was able to suppress hPDLCs proliferation and promote apoptosis in hypoxia conditions. The mRNA and protein expressions of IGF-1 were downregulated when miR-646 was overexpressed and upregulated when miR-646 was downregulated.

CONCLUSIONS: This finding identified a significant role of miR-646 in hPDLCs in suppressing cell proliferation and promoting apoptosis by inversely regulating IGF-1 expression. Meanwhile, the regulation of hPDLCs in hypoxia may be through the miR-646/IGF-1 signaling pathway, probably serving as a promising therapeutic target for periodontal diseases.

Keywords: Cell Hypoxia, Insulin-Like Growth Factor I