Ca_v1.2 of L-type Calcium Channel Is a Key Factor for the Differentiation of Dental Pulp Stem Cells

Introduction L-type calcium channel (LTCC) is a unique and important factor in several cell lineages, whereas its role in the differentiation of dental pulp stem cells (DPSCs) is not well-known. In this study, we examined the function of LTCC α1C subunit (Ca_v1.2) and its distal C-terminus (DCT) during the in vitro differentiation of rat DPSCs (rDPSCs). Methods After fluorescence-activated cell sorting, rDPSCs were differentiated toward dentin sialophosphoprotein-positive odontoblasts and neural cells expressing specific neuronal markers. The inhibition of rDPSC differentiation via LTCC blocker nimodipine and Ca_v1.2 knockdown through short hairpin RNA was evaluated by using quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence staining. Results Nimodipine treatment and Ca_v1.2 knockdown generated similar results. The number of positive calcium nodules and the protein and mRNA levels of dentin sialophosphoprotein were significantly reduced during odontogenic differentiation. The levels of microtubule-associated protein-2 and β-III-tubulin were reduced in neural differentiation. The expression of DCT decreased after odontogenic differentiation but significantly increased after neural differentiation (P <.05, n = 9). Conclusions Our data showed that LTCC blocker nimodipine inhibits the odontogenic and neural differentiation of rDPSCs, and Ca_v1.2 is responsible for the activity of LTCC. The expression of DCT of Ca_v1.2 significantly changes during both odontogenic and neural differentiation. Thus, Ca_v1.2 of LTCC plays an essential role in differentiation of DPSCs, which might be mediated through the regulation of DCT levels in DPSCs.