title: Connexin43-containing gap junctions potentiate extracellular Ca²⁺-induced odontoblastic differentiation of human dental pulp stem cells via Erk1/2.
abstract: Extracellular Ca(2+) can promote dentin sialophosphoprotein (DSPP) expression and odontoblastic differentiation of dental pulp stem cells (DPSCs). Gap junctions mediated by connexin43 (Cx43) allow diffusion of small molecules (such as Ca(2+)) among cells to regulate cell-to-cell communications. However, it is unclear whether Cx43 is required for the Ca(2+)-induced cell differentiation. Here, we found that the influx of extracellular Ca(2+) through L-type Ca(2+) channels increases intracellular free Ca(2+) levels to promote DSPP expression. Cx43 overexpression potentiated the extracellular Ca(2+)-induced DSPP expression via Erk1/2. Flow cytometry analyses showed that Cx43 increased the percentage of p-Erk1/2 positive cells in response to Ca(2+), indicating that Cx43 in DPSCs possibly acts as a traditional gap junction channel, which permits the sharing of signals among coupled cells to make more DPSCs respond to Ca(2+). Furthermore, inhibition of Cx43 function and gap junction communication decreased Ca(2+)-induced the expression of DSPP, suggesting that cell-to-cell contacts are required for Cx43 to promote the Ca(2+)-induced cell differentiation. Similarly, the study performed on DPSCs cultured at low-density and high-density revealed that intercellular contacts are required to potentiate Erk1/2 activity and DSPP expression. In total, this study indicates that Cx43 increases Ca(2+)-induced DSPP expression and odontoblastic differentiation of DPSCs via Erk1/2 through gap junction-mediated cell-to-cell contacts.
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: tingtinghigh@sina.com.
authors.forename: Shiting
authors.initials: S
authors.lastname: Li
authors.affiliation: Maxillofacial and Head-Neck and Surgery, Daping Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: 478009847@qq.com.
authors.forename: Haitao
authors.initials: H
authors.lastname: He
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: 535291232@qq.com.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: 374346301@qq.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: 16943843@qq.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: tanyh19621030@outlook.com.
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Tan
mesh_terms: D000328:Adult; D053687:Adult Stem Cells / Q000502:physiology*; D002118:Calcium / Q000502:physiology; D020013:Calcium Signaling; D002454:Cell Differentiation; D018031:Connexin 43 / Q000502:physiology*; D003782:Dental Pulp / Q000166:cytology; D016326:Extracellular Matrix Proteins; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D017629:Gap Junctions / Q000502:physiology*; D006801:Humans; D020935:MAP Kinase Signaling System; D009804:Odontoblasts / Q000502:physiology*; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D055815:Young Adult; D000099311:Dentin Sialophosphoprotein
chemical_list: D002118:Calcium; D018031:Connexin 43; D016326:Extracellular Matrix Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D010750:Phosphoproteins; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C500216:GJA1 protein, human
keywords: Cell differentiation; Connexin43; Dental pulp stem cells (DPSCs); Extracellular Ca(2+); Gap junctions