Background Chondrocyte apoptosis is a central feature in the progression of osteoarthritis (OA), and would be triggered by sustained elevation of intracellular calcium ion (Ca2+), also known as a cellular second messenger. Transient receptor potential ankyrin 1 (TRPA1) is a membrane-associated cation channel, and the activation of which causes an influx of cation ions, in particularly Ca2+, into the activated cells. Therefore, we investigate the potential role of TRPA1 in mediating Ca2+ influx to promote chondrocyte apoptosis in OA. Methods The expression of TRPA1 in interleukin (IL)-1β-treated rat chondrocytes was assessed by Polymerase chain reaction (PCR) and Western blot (WB), and the functionality of TRPA1 channel by Ca2+ influx measurements. Meanwhile, the chondrocyte apoptosis in IL-1β-treated cells was measured by TUNEL assay and flow cytometry. The measurement of mitochondrial membrane potential and apoptosis-associated proteins after inhibition of TRPA1 were also performed in IL-1β-treated rat chondrocytes. Results After being induced by IL-1β, the gene and protein expression of TRPA1 was increased in the dose-dependent manner. Meanwhile, Ca2+ influx mediated by TRPA1 in rat chondrocytes was also enhanced. Pharmacological inhibition of TRPA1 downregulated the apoptotic rate in IL-1β-treated rat chondrocytes. In addition, the membrane potential depolarization was improved and significantly increased expression of apoptosis-associated proteins also reduced by the TRPA1 antagonist. Conclusions We found the IL-1β caused the increased functional expression of TRPA1, the activation of which involved IL-1β-induced apoptosis in rat chondrocytes. The potential mechanism may be linked to the intracellular calcium overload mediated by TRPA1 and attendant mitochondrial dysfunction.

中文翻译：

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瞬时受体电位锚蛋白 1 (trpa1) 通过钙超载和线粒体功能障碍介导 il-1β 诱导的大鼠软骨细胞凋亡。

背景 软骨细胞凋亡是骨关节炎 (OA) 进展的核心特征，并且会由细胞内钙离子 (Ca2+) 的持续升高触发，钙离子 (Ca2+) 也称为细胞第二信使。瞬时受体电位锚蛋白 1 (TRPA1) 是一种与膜相关的阳离子通道，其激活会导致阳离子离子，特别是 Ca2+ 流入激活的细胞。因此，我们研究了 TRPA1 在介导 Ca2+ 流入以促进 OA 中软骨细胞凋亡中的潜在作用。方法通过聚合酶链反应（PCR）和蛋白质印迹（WB）评估白细胞介素（IL）-1β处理的大鼠软骨细胞中TRPA1的表达，并通过Ca2+流入测量TRPA1通道的功能。同时，通过 TUNEL 测定和流式细胞术测量 IL-1β 处理的细胞中的软骨细胞凋亡。还在 IL-1β 处理的大鼠软骨细胞中进行了 TRPA1 抑制后线粒体膜电位和凋亡相关蛋白的测量。结果在IL-1β诱导后，TRPA1基因和蛋白表达呈剂量依赖性增加。同时，大鼠软骨细胞中TRPA1介导的Ca2+内流也增强。TRPA1的药理抑制下调IL-1β处理的大鼠软骨细胞的凋亡率。此外，膜电位去极化得到改善，细胞凋亡相关蛋白的表达显着增加，也被 TRPA1 拮抗剂降低。结论 我们发现 IL-1β 导致 TRPA1 的功能表达增加，其激活涉及 IL-1β 诱导的大鼠软骨细胞凋亡。潜在的机制可能与 TRPA1 介导的细胞内钙超载和伴随的线粒体功能障碍有关。