Contribution of TRPC Channels to Intracellular Ca2+ Dyshomeostasis in Smooth Muscle From mdx Mice
Contribution of TRPC Channels to Intracellular Ca2+ Dyshomeostasis in Smooth Muscle From mdx Mice
复制标题
DOI：
10.3389/fphys.2020.00126
复制
发表时间：
2020-02-20
影响因子：
4
通讯作者：
Adams, Jose A.
中科院分区：
文献类型：
--
作者：
Lopez, Jose R.;Uryash, Arkady;Adams, Jose A.
杜氏肌营养不良症（DMD）是一种不可逆的肌肉疾病，其特征在于肌肉功能的进行性丧失、肌张力降低，并且最终由于心脏或呼吸衰竭而死亡。DMD是由肌营养不良蛋白的缺乏引起的，肌营养不良蛋白是一种对可兴奋细胞中的膜稳定性和信号传导很重要的蛋白质。虽然血管平滑肌细胞（VSMCs）功能障碍发生在许多病理条件下，很少有人知道DMD的血管平滑肌功能。我们先前已经表明，与野生型（Wt）相比，从营养不良（mdx）小鼠分离的横纹肌细胞以及神经元具有较高的细胞内Ca 2+（[Ca 2 +]（i））和Na+（[Na+]（i））浓度和降低的细胞活力。实验在来自mdx（DMD的鼠模型）和同源C57 BL/10 SnJ Wt小鼠的分离的VSMC中进行。我们发现与Wt相比，mdx小鼠的VSMCs中[Ca 2 +]（i）和[Na+]（i）升高。暴露于TRPC 3和TRPC 6通道激活剂1-油酰基-2-乙酰基-sn-甘油（OAG）诱导mdx中[Ca 2 +]（i）和[Na+]（i）的升高大于Wt VSMCs。OAG诱导的[Ca ~（2+）]（i）增加可通过清除细胞外Ca ~（2+）或SAR 7334（两种基因型中TRPC 3和TRPC 6通道的阻断剂）消除。Mdx和Wt VSMCs对牵张诱导的[Ca ~（2+）]（i）和[Na ~+]（i）升高敏感，而GsMTx-4（一种机械敏感性离子通道抑制剂）可完全抑制牵张诱导的[Ca ~（2+）]（i）和[Na ~+]（i）升高。Western印迹显示与年龄匹配的Wt. mdx VSMC中肌营养不良蛋白的缺乏产生了[Ca 2 +]（i）和[Na+]（i）稳态的深刻改变，这似乎是由TRPC通道介导的。此外，我们已经能够证明，mdx VSMC中增强的牵张诱导的细胞内[Ca 2 +]升高和伴随的细胞损伤似乎也是通过TRPC 1，-3和-6通道激活介导的。
Duchenne muscular dystrophy (DMD) is an irreversible muscle disease characterized by a progressive loss of muscle function, decreased ambulation, and ultimately death as a result of cardiac or respiratory failure. DMD is caused by the lack of dystrophin, a protein that is important for membrane stability and signaling in excitable cells. Although vascular smooth muscle cells (VSMCs) dysfunction occurs in many pathological conditions, little is known about vascular smooth muscle function in DMD. We have previously shown that striated muscle cells, as well as neurons isolated from dystrophic (mdx) mice have higher intracellular Ca2+ ([Ca2+](i)) and Na+ ([Na+](i)) concentrations and decreased cell viability in comparison with wild type (Wt). Experiments were carried out in isolated VSMCs from mdx (a murine model of DMD) and congenic C57BL/10SnJ Wt mice. We found elevated [Ca2+](i) and [Na+](i) in VSMCs from mdx mice compared to Wt. Exposure to 1-oleoyl-2-acetyl-sn-glycerol (OAG), a TRPC3 and TRPC6 channel activator, induced a greater elevation of [Ca2+](i) and [Na+](i) in mdx than Wt VSMCs. The OAG induced increases in [Ca2+](i) could be abolished by either removal of extracellular Ca2+ or by SAR7334, a blocker of TRPC3 and TRPC 6 channels in both genotypes. Mdx and Wt VSMCs were susceptible to muscle cell stretch-induced elevations of [Ca2+](i) and [Na+](i) which was completely inhibited by GsMTx-4, a mechanosensitive ion channel inhibitor. Western blots showed a significant upregulation of TRPC1 -3, -6 proteins in mdx VSMCs compare to age-matched Wt. The lack of dystrophin in mdx VSMCs produced a profound alteration of [Ca2+](i) and [Na+](i) homeostasis that appears to be mediated by TRPC channels. Moreover, we have been able to demonstrate pharmacologically that the enhanced stretch-induced elevation of intracellular [Ca2+] and concomitant cell damage in mdx VSMCs also appears to be mediated through TRPC1, -3 and -6 channel activation.