Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA.
Osteoarthritis Cartilage. 2019 Apr;27(4):703-711. doi: 10.1016/j.joca.2018.12.010. Epub 2018 Dec 24.
To compare key intracellular redox-regulated signaling pathways in chondrocytes derived from knee joint femoral cartilage and ankle joint talar cartilage in order to determine if differences exist that might contribute to the lower prevalence of ankle osteoarthritis (OA).
Femoral and talar chondrocytes were treated with HO generators (menadione or 2-3-dimethoxy-1,4-napthoquinone (DMNQ), fragments of fibronectin (FN-f)) to stimulate MAP kinase signaling (MAPK), or with IGF-1 to stimulate the Akt signaling pathway. Hyperoxidation of the peroxiredoxins, used as a measure of redox status, and phosphorylation of proteins pertinent to MAPK (p38, ERK, JNK, c-Jun) and Akt (Akt, PRAS40) signaling cascades were detected by immunoblotting.
Treatment of femoral and talar chondrocytes with menadione, DMNQ or FN-f led to a time dependent increase in extracellular-regulated kinase (ERK) and p38 phosphorylation. DMNQ and FN-f stimulation enhanced phosphorylation of JNK and its downstream substrate, c-Jun. Menadione treatment did not stimulate JNK activity but hyperoxidized the peroxiredoxins and inhibited IGF-1-induced Akt activation. In all experiments, chondrocytes derived from the femur and talar joints displayed comparable MAP kinase responses after treatment with various catabolic stimuli, as well as similar Akt signaling responses after IGF-1 treatment.
MAP kinase and Akt signaling in response to factors that modulate the intracellular redox status were similar in chondrocytes from knee and ankle joints suggesting that redox signaling differences do not explain differences in OA prevalence. Talar chondrocytes, when isolated from their native matrix, can be used to examine redox-regulated cell signaling events relevant to OA in either joint.
比较膝关节股骨软骨和踝关节距骨软骨来源的软骨细胞中关键的细胞内氧化还原调节信号通路，以确定是否存在差异，这些差异可能导致踝关节骨关节炎（OA）的患病率较低。
用 HO 生成剂（甲萘醌或 2-3-二甲氧基-1,4-萘醌（DMNQ）、纤维连接蛋白（FN-f）片段）处理股骨和距骨软骨细胞，以刺激 MAP 激酶信号通路（MAPK），或用 IGF-1 刺激 Akt 信号通路。过氧化物酶的超氧化作用，用作氧化还原状态的衡量标准，以及与 MAPK（p38、ERK、JNK、c-Jun）和 Akt（Akt、PRAS40）信号级联相关的蛋白质的磷酸化，通过免疫印迹检测。
用甲萘醌、DMNQ 或 FN-f 处理股骨和距骨软骨细胞，导致细胞外调节激酶（ERK）和 p38 磷酸化的时间依赖性增加。DMNQ 和 FN-f 刺激增强了 JNK 的磷酸化及其下游底物 c-Jun。甲萘醌处理不会刺激 JNK 活性，但会超氧化过氧化物酶并抑制 IGF-1 诱导的 Akt 激活。在所有实验中，用各种分解代谢刺激物处理后，来自股骨和距骨关节的软骨细胞显示出相似的 MAP 激酶反应，以及 IGF-1 处理后相似的 Akt 信号反应。
调节细胞内氧化还原状态的因素对 MAP 激酶和 Akt 信号的反应在膝关节和踝关节软骨细胞中相似，表明氧化还原信号差异不能解释 OA 患病率的差异。从其天然基质中分离出来的距骨软骨细胞可用于研究与任何关节 OA 相关的氧化还原调节细胞信号事件。
