Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
Neuroscience. 2017 Sep 30;360:61-67. doi: 10.1016/j.neuroscience.2017.07.050. Epub 2017 Jul 27.
Tissue engineering protocols, such as regenerative endodontic procedures (REPs), comprise biologically based procedures designed to restore normal physiologic function. For REPs, the goal is reconstitution of the pulp-dentin complex by delivering mesenchymal stem cells (MSCs), including the stem cells of the apical papilla (SCAP) into a root canal system. Many patients regain cold sensitivity after REPs, but the mechanism is not understood. We hypothesized that SCAP modulate nociceptive function through a paracrine mechanism that activates cold-sensitive ion channels in neurons. We established a co-culture system with human SCAP and rat trigeminal (TG) sensory neurons in order to determine the effect of SCAP co-culture on neuronal responses using whole-cell patch-clamp electrophysiology. TG neurons co-cultured with SCAP demonstrated increased TRPA1-mediated (p<0.01) and TRPM8-mediated inward current densities (p<0.01) at 24h in co-culture. Cold stimulation to SCAP significantly increased ATP release (p<0.01), and supernatant collected after cold stimulation to SCAP was able to activate cultured TG neurons. Co-culture with SCAP significantly increased sustained ATP-evoked inward current density (p<0.05). These data suggest that SCAP release trophic factors that act on afferent neurons to enhance cold-sensitive ion channel activity.
组织工程学方案，如再生牙髓治疗程序（REPs），包括旨在恢复正常生理功能的基于生物学的程序。对于 REPs，目标是通过将间充质干细胞（MSCs），包括根尖乳头干细胞（SCAP）递送至根管系统中来重建牙髓-牙本质复合体。许多患者在 REPs 后恢复了冷敏感性，但机制尚不清楚。我们假设 SCAP 通过旁分泌机制来调节伤害感受功能，该机制激活神经元中的冷敏感离子通道。我们建立了人 SCAP 和大鼠三叉神经（TG）感觉神经元的共培养系统，以便使用全细胞膜片钳电生理学来确定 SCAP 共培养对神经元反应的影响。与 SCAP 共培养的 TG 神经元在共培养 24 小时时显示出 TRPA1 介导的（p<0.01）和 TRPM8 介导的内向电流密度（p<0.01）增加。冷刺激 SCAP 可显著增加 ATP 释放（p<0.01），并且冷刺激 SCAP 后收集的上清液能够激活培养的 TG 神经元。与 SCAP 共培养可显著增加持续的 ATP 诱发的内向电流密度（p<0.05）。这些数据表明，SCAP 释放的营养因子作用于传入神经元，以增强冷敏感离子通道活性。
