Microdamage induced calcium efflux from bone matrix activates intracellular calcium signaling in osteoblasts via L-type and T-type voltage-gated calcium channels
Microdamage induced calcium efflux from bone matrix activates intracellular calcium signaling in osteoblasts via L-type and T-type voltage-gated calcium channels
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DOI：
10.1016/j.bone.2015.03.014
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发表时间：
2015-07-01
期刊：
影响因子：
4.1
通讯作者：
Akkus, Ozan
中科院分区：
文献类型：
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作者：
Jung, Hyungjin;Best, Makenzie;Akkus, Ozan
骨微损伤触发修复反应的机制尚不完全清楚。研究表明，钙外流 ([Ca2+](E)) 发生在遭受微损伤的骨骼区域。这种流出还被证明可以触发受损区域局部 MC3T3-E1 细胞中的细胞内钙信号传导 ([Ca2+)(I)]。电压门控钙通道 (VGCC) 参与 [Ca2+](E) 进入细胞质。我们研究了 VGCC 在细胞外钙诱导的细胞内钙反应 (ECIICR) 中的参与。 MC3T3-E1 细胞从其基底受到一维钙流出，导致 [Ca2+](I) 增加。这种增加伴随着膜去极化，并且在非选择性 VGCC 抑制剂 Bepridil 存在下显着减少。为了识别 ECIICR 中 VGCC 的特定类型，用针对不同类型 VGCC 的选择性抑制剂处理细胞。当使用 L 型和 T 型特异性 VGCC 抑制剂（分别为维拉帕米和 NNC55-0396）时，观察到峰强度和 [Ca2+](I) 振荡数量发生显着变化。为了确认 L 型和 T 型 VGCC 在微损伤中的参与，将细胞接种在失活的有缺口的骨样本上，加载这些样本以在维拉帕米和 NNC55-0396 存在和不存在的情况下诱导微损伤。结果显示，当应用 L 型和 T 型阻滞剂时，骨微损伤区域细胞的 [Ca2+](I) 活性显着降低。这项研究表明，与损伤相关的细胞外钙增加会使细胞膜去极化，钙离子通过 L 型和 T 型 VGCC 进入细胞质。 (C) 2015 Elsevier Inc. 保留所有权利。
Mechanisms by which bone microdamage triggers repair response are not completely understood. It has been shown that calcium efflux ([Ca2+](E)) occurs from regions of bone undergoing microdamage. Such efflux has also been shown to trigger intracellular calcium signaling ([Ca2+)(I)] in MC3T3-E1 cells local to damaged regions. Voltage-gated calcium channels (VGCCs) are implicated in the entry of [Ca2+](E) to the cytoplasm. We investigated the involvement of VGCC in the extracellular calcium induced intracellular calcium response (ECIICR). MC3T3-E1 cells were subjected to one dimensional calcium efflux from their basal aspect which results in an increase in [Ca2+](I). This increase was concomitant with membrane depolarization and it was significantly reduced in the presence of Bepridil, a non-selective VGCC inhibitor. To identify specific type(s) of VGCC in ECIICR, the cells were treated with selective inhibitors for different types of VGCC. Significant changes in the peak intensity and the number of [Ca2+](I) oscillations were observed when L-type and T-type specific VGCC inhibitors (Verapamil and NNC55-0396, respectively) were used. So as to confirm the involvement of L- and T-type VGCC in the context of microdamage, cells were seeded on devitalized notched bone specimen, which were loaded to induce microdamage in the presence and absence of Verapamil and NNC55-0396. The results showed significant decrease in [Ca2+](I) activity of cells in the microdamaged regions of bone when L- and T-type blockers were applied. This study demonstrated that extracellular calcium increase in association with damage depolarizes the cell membrane and the calcium ions enter the cell cytoplasm by L- and T-type VGCCs. (C) 2015 Elsevier Inc. All rights reserved.