Anhui Key Laboratory of Bioactivity of Natural Products, School of Pharmacy, Anhui Medical University, Hefei 230032, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.
Anhui Key Laboratory of Bioactivity of Natural Products, School of Pharmacy, Anhui Medical University, Hefei 230032, China; The Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Hefei 230032, China.
Biochim Biophys Acta Mol Basis Dis. 2018 Jan;1864(1):162-177. doi: 10.1016/j.bbadis.2017.10.004. Epub 2017 Oct 3.
The acute-phase proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) demonstrate high-level expression and pleiotropic biological effects, and contribute to the progression and persistence of rheumatoid arthritis (RA). Acid hydrarthrosis is also an important pathological characteristic of RA, and the acid-sensing ion channel 1a (ASIC1a) plays a critical role in acidosis-induced chondrocyte cytotoxicity. However, the roles of IL-1β and TNF-α in acid-induced apoptosis of chondrocytes remain unclear. Rat adjuvant arthritis and primary articular chondrocytes were used as in vivo and in vitro model systems, respectively. ASIC1a expression in articular cartilage was increased and highly colocalized with nuclear factor (NF)-κB expression in vivo. IL-1β and TNF-α could upregulate ASIC1a expression. These cytokines activated mitogen-activated protein kinase and NF-κB pathways in chondrocytes, while the respective inhibitors of these signaling pathways could partially reverse the ASIC1a upregulation induced by IL-1β and TNF-α. Dual luciferase and gel-shift assays and chromatin immunoprecipitation-polymerase chain reaction demonstrated that IL-1β and TNF-α enhanced ASIC1a promoter activity in chondrocytes by increasing NF-κB DNA-binding activities, which was in turn prevented by the NF-κB inhibitor ammonium pyrrolidinedithiocarbamate. IL-1β and TNF-α also decreased cell viability but enhanced LDH release, intracellular Ca concentration elevation, loss of mitochondrial membrane potential, cleaved PARP and cleaved caspase-3/9 expression, and apoptosis in acid-stimulated chondrocytes, which effects could be abrogated by the specific ASIC1a inhibitor psalmotoxin-1 (PcTX-1), ASIC1a-short hairpin RNA or calcium chelating agent BAPTA-AM. These results indicate that IL-1β and TNF-α can augment acidosis-induced cytotoxicity through NF-κB-dependent up-regulation of ASIC1a channel expression in primary articular chondrocytes.
急性期促炎细胞因子白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF-α）表现出高水平的表达和多种生物学效应，有助于类风湿关节炎（RA）的进展和持续存在。酸性滑液也是 RA 的一个重要病理特征，酸感应离子通道 1a（ASIC1a）在酸中毒诱导的软骨细胞细胞毒性中发挥关键作用。然而，IL-1β和 TNF-α在酸性诱导的软骨细胞凋亡中的作用尚不清楚。大鼠佐剂关节炎和原代关节软骨细胞分别作为体内和体外模型系统。体内研究发现，关节软骨中 ASIC1a 的表达增加，并与核因子（NF）-κB 的表达高度共定位。IL-1β和 TNF-α可上调 ASIC1a 的表达。这些细胞因子激活了软骨细胞中的丝裂原活化蛋白激酶和 NF-κB 途径，而这些信号通路的抑制剂可部分逆转 IL-1β和 TNF-α诱导的 ASIC1a 上调。双荧光素酶和凝胶阻滞实验以及染色质免疫沉淀-聚合酶链反应表明，IL-1β和 TNF-α通过增加 NF-κB 的 DNA 结合活性增强了软骨细胞中 ASIC1a 启动子的活性，而 NF-κB 抑制剂氨吡咯烷二硫代氨基甲酸盐可阻止这种作用。IL-1β和 TNF-α还降低了细胞活力，但增加了 LDH 释放、细胞内 Ca2+浓度升高、线粒体膜电位丧失、PARP 切割和 caspase-3/9 切割表达以及酸性刺激软骨细胞中的凋亡，这些作用可被特异性 ASIC1a 抑制剂 psalmotoxin-1（PcTX-1）、ASIC1a-short hairpin RNA 或钙螯合剂 BAPTA-AM 所阻断。这些结果表明，IL-1β和 TNF-α可以通过 NF-κB 依赖性上调原代关节软骨细胞中的 ASIC1a 通道表达来增强酸中毒诱导的细胞毒性。
