TRPM7 is Involved in the Regulation of Proliferation, Migration and Osteogenic Differentiation of Human Dental Follicle Cells

Background: Dental follicle cells (DFCs) are promising candidates for tissue engineering. However, the molecular mechanisms that regulate the biological characteristics of DFCs are still unclear. Transient receptor potential melastatin 7 (TRPM7) is a Ca2+- and Mg2+-permeable cation channel. The aim of this study was to determine the impact of TRPM7 on the proliferation, migration and osteogenic differentiation of DFCs.

Methods: PCR, Western blotting, Immunocytochemical staining and Patch clamp methods were used to identify the gene and protein expression of TRPM7 in DFCs. DFCs were infected with lentiviruses that expressed either TRPM7 specific shRNA or scrambled non-effective shRNA to investigate its functional role. Cell proliferation and migration were assessed using Cell Counting Kit-8 assays and transwell cell culture chambers separately. Cell osteogenic differentiation were determined by ALP assay kit and Alizarin Red staining.

Results: Gene and protein expression of TRPM7 were detected in DFCs, but not of TRPM6, which is a closely related channel with similar function. In the absence of Mg2+, typical whole cell TRPM7-like currents were recorded by patch clamp. These were inhibited by low concentrations of 2-APB, but activated by high concentrations of 2-APB. Functional studies demonstrated that suppression of TRPM7 expression inhibited the proliferation and migration of DFCs, and promoted their osteogenic differentiation. Furthermore, Mg2+ deficiency mimicked the effects of TRPM7 knockdown in terms of osteogenic differentiation of DFCs.

Conclusions: These results demonstrate that TRPM7 is involved in regulating the proliferation, migration and osteogenic differentiation of DFCs.