Purinergic and Store‐Operated Ca2+ Signaling Mechanisms in Mesenchymal Stem Cells and Their Roles in ATP‐Induced Stimulation of Cell Migration

• Published in: Stem cells (Dayton, Ohio) Vol. 34; no. 8; pp. 2102 - 2114
• Main Authors: Peng, Hongsen, Hao, Yunjie, Mousawi, Fatema, Roger, Sebastien, Li, Jing, Sim, Joan A., Ponnambalam, Sreenivasan, Yang, Xuebin, Jiang, Lin‐Hua
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-08-2016
• Subjects: Activation; Adenosine triphosphatase; ATP; Buildings; Calcium channels; Calcium signalling; Cell adhesion & migration; Cell migration; Control; Dental pulp; Homeostasis; Homing; Homing behavior; Interrogation; Mesenchymal stem cells; Mesenchyme; Molecular modelling; Orai1 protein; Pharmacology; Polymerase chain reaction; Purine P2Y receptors; Receptor mechanisms; Receptors; Stem cells; STIM1 protein; Stimulation; Therapeutic applications
• ISSN: 1066-5099; 1549-4918
• DOI: 10.1002/stem.2370

ATP is an extrinsic signal that can induce an increase in the cytosolic Ca2+ level ([Ca2+]c) in mesenchymal stem cells (MSCs). However, the cognate intrinsic mechanisms underlying ATP‐induced Ca2+ signaling in MSCs is still contentious, and their importance in MSC migration remains unknown. In this study, we investigated the molecular mechanisms underlying ATP‐induced Ca2+ signaling and their roles in the regulation of cell migration in human dental pulp MSCs (hDP‐MSCs). RT‐PCR analysis of mRNA transcripts and interrogation of agonist‐induced increases in the [Ca2+]c support that P2X7, P2Y1, and P2Y11 receptors participate in ATP‐induced Ca2+ signaling. In addition, following P2Y receptor activation, Ca2+ release‐activated Ca2+ Orai1/Stim1 channel as a downstream mechanism also plays a significant role in ATP‐induced Ca2+ signaling. ATP concentration‐dependently stimulates hDP‐MSC migration. Pharmacological and genetic interventions of the expression or function of the P2X7, P2Y1 and P2Y11 receptors, and Orai1/Stim1 channel support critical involvement of these Ca2+ signaling mechanisms in ATP‐induced stimulation of hDP‐MSC migration. Taken together, this study provide evidence to show that purinergic P2X7, P2Y1, and P2Y11 receptors and store‐operated Orai1/Stim1 channel represent important molecular mechanisms responsible for ATP‐induced Ca2+ signaling in hDP‐MSCs and activation of these mechanisms stimulates hDP‐MSC migration. Such information is useful in building a mechanistic understanding of MSC homing in tissue homeostasis and developing more efficient MSC‐based therapeutic applications. Stem Cells 2016;34:2102–2114
iATP as an extrinsic signal activates purinergic P2X7, P2Y1 and P2Y11 receptors on mesenchymal stem cell (MSC) derived from human dental pulp. Activation of the P2Y1 and P2Y11 receptors stimulates phospholipase C (PLC) via the Gα,11 protein, leading to production of IP3 from the membrane lipid PIP2, IP3 receptor (IP3R)‐mediated Ca2+ release from the endoplasmic reticulum (ER) and STIM1‐dependent gating of the Orai1 channel. ATP can also activate the P2X7 receptor ion channel. Both Orai1 and P2X7 channels mediate extracellular Ca2+ influx, resulting in an increase in the cytosolic Ca2+ level. Such ATP‐induced Ca2+ signalling mechanisms promote MSC migration.