High pH-Sensitive TRPA1 Activation in Odontoblasts Regulates Mineralization
High pH-Sensitive TRPA1 Activation in Odontoblasts Regulates Mineralization
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DOI：
10.1177/0022034516644702
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发表时间：
2016-08-01
影响因子：
7.6
通讯作者：
Shibukawa, Y.
中科院分区：
文献类型：
--
作者：
Kimura, M.;Sase, T.;Shibukawa, Y.
氢氧化钙和无机三氧化物聚合体广泛用于间接和直接盖髓和根管充填。它们在牙髓中解离成Ca 2+和OH-，产生碱性环境，激活修复性/反应性牙本质形成。然而，成牙本质细胞检测细胞外环境pH值的机制仍不清楚。我们研究了大鼠成牙本质细胞中碱敏感的细胞内Ca 2+信号通路。在细胞外Ca ~（2+）存在或不存在的情况下，碱性溶液的应用增加了细胞内Ca ~（2+）浓度，或[Ca ~（2+）]i。碱性溶液诱导的[Ca 2 +] i增加依赖于细胞外pH值（8.5至10.5）的情况下和存在的细胞外Ca 2+。在没有细胞外Ca 2+的情况下，振幅小于存在细胞外Ca 2+的情况下。由pH 7.5、8.5或9.5激活的[Ca 2 +] i的每次增加取决于细胞外Ca 2+浓度;细胞外Ca 2+浓度的平衡结合常数随着细胞外pH的增加而降低（pH 7.5时为1.04 mM，pH 9.5时为0.11 mM）。重复应用碱性溶液并没有对碱诱导的[Ca 2 +] i增加和内向电流的脱敏作用。在细胞外Ca 2+的存在下，碱性溶液诱导的[Ca 2 +] i增加被抑制的瞬时受体电位锚蛋白亚家族成员1（TRPA 1）通道的拮抗剂的应用。Na+-Ca 2+交换拮抗剂可降低碱性溶液诱导的[Ca 2 +] i增加过程中的Ca 2+排斥效率。茜素红和von Kossa染色显示，在反复高pH刺激下矿化水平增加，而TRPA 1拮抗剂强烈降低了这种作用。这些发现表明，碱性刺激，如氢氧化钙或矿物三氧化物聚合物处理的牙髓内的碱性环境激活Ca 2+动员通过Ca 2+内流介导的TRPA 1通道和细胞内Ca 2+释放成牙本质细胞。成牙本质细胞的高pH敏感机制对于激活碱性环境诱导的牙本质形成是重要的。
Calcium hydroxide and mineral trioxide aggregate are widely used for indirect and direct pulp capping and root canal filling. Their dissociation into Ca2+ and OH- in dental pulp creates an alkaline environment, which activates reparative/reactionary dentinogenesis. However, the mechanisms by which odontoblasts detect the pH of the extracellular environment remain unclear. We examined the alkali-sensitive intracellular Ca2+ signaling pathway in rat odontoblasts. In the presence or absence of extracellular Ca2+, application of alkaline solution increased intracellular Ca2+ concentration, or [Ca2+]i. Alkaline solution-induced [Ca2+] i increases depended on extracellular pH (8.5 to 10.5) in both the absence and the presence of extracellular Ca2+. The amplitude was smaller in the absence than in the presence of extracellular Ca2+. Each increase in [Ca2+] i, activated by pH 7.5, 8.5, or 9.5, depended on extracellular Ca2+ concentration; the equilibrium binding constant for extracellular Ca2+ concentration decreased as extracellular pH increased (1.04 mM at pH 7.5 to 0.11 mM at pH 9.5). Repeated applications of alkaline solution did not have a desensitizing effect on alkali-induced [Ca2+] i increases and inward currents. In the presence of extracellular Ca2+, alkaline solution-induced [Ca2+] i increases were suppressed by application of an antagonist of transient receptor potential ankyrin subfamily member 1 (TRPA1) channels. Ca2+ exclusion efficiency during alkaline solution-induced [Ca2+] i increases was reduced by a Na+- Ca2+ exchanger antagonist. Alizarin red and von Kossa staining revealed increased mineralization levels under repeated high pH stimulation, whereas the TRPA1 antagonist strongly reduced this effect. These findings indicate that alkaline stimuli-such as the alkaline environment inside dental pulp treated with calcium hydroxide or mineral trioxide aggregate-activate Ca2+ mobilization via Ca2+ influx mediated by TRPA1 channels and intracellular Ca2+ release in odontoblasts. High pH-sensing mechanisms in odontoblasts are important for activating dentinogenesis induced by an alkaline environment.