Cav1.2 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 (Cav1.2) 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 Cav1.2 knockdown through short hairpin RNA was evaluated by using quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence staining.

Results: Nimodipine treatment and Cav1.2 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 Cav1.2 is responsible for the activity of LTCC. The expression of DCT of Cav1.2 significantly changes during both odontogenic and neural differentiation. Thus, Cav1.2 of LTCC plays an essential role in differentiation of DPSCs, which might be mediated through the regulation of DCT levels in DPSCs.