Granular corneal dystrophy (GCD) is featured by corneal deposits of transforming growth factor beta-induced gene (TGFBI) mediated by the TGF-β (transforming growth factor-β)/Smad signaling. However, the roles of c-Jun amino-terminal kinase (JNK) pathway in GCD pathogenesis remains unexplored, which was investigated in this study. JNK signaling activation and inhibition in primary corneal fibroblasts were obtained by treatments with anisomycin and SP600125, respectively. Protein abundance and phosphorylation were detected by immunoblotting. Cell viability and apoptosis were analyzed by CCK-8 and flow cytometry respectively. TGFBI deposit and autophagy progression were assessed by immunofluorescence. The results found that JNK1 expression and phosphorylation were greatly increased in corneal tissues from GCD2 patients. JNK signaling activation impaired the viability and promoted apoptosis and autophagy processes in primary corneal fibroblasts, along with Smad2/3 phosphorylation, TGFBI accumulation and Bcl-2 suppression. Autophagy related proteins, such as ATG5 (autophagy related 5), ATG12 (autophagy related 12) and LC3B (microtubule-associated protein 1 light chain 3 beta), were also increased in anisomycin or TGF-β1 treated corneal fibroblasts. However, SP600125 effectively reversed the above effect induced by TGF-β1 treatment in corneal fibroblasts, including the TGF-β-induced autophagy progression. The results suggested that JNK signaling was activated in GCD2 corneal tissues, and it mediated the TGF-β-induced TGFBI protein accumulation and apoptosis of corneal fibroblasts during GCD2 pathogenesis.

中文翻译：

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通过调节TGF-β诱导的TGFBI表达和角膜成纤维细胞凋亡，JNK信号传导参与粒状角膜营养不良。

颗粒状角膜营养不良（GCD）的特征在于由TGF-β（转化生长因子-β）/ Smad信号介导的转化生长因子β诱导基因（TGFBI）的角膜沉积。然而，c-Jun氨基末端激酶（JNK）途径在GCD发病机理中的作用尚待探索，本研究对此进行了研究。通过分别用茴香霉素和SP600125处理获得原代角膜成纤维细胞中JNK信号的激活和抑制。通过免疫印迹检测蛋白质丰度和磷酸化。通过CCK-8和流式细胞术分别分析细胞活力和凋亡。通过免疫荧光评估TGFBI沉积和自噬进程。结果发现，在GCD2患者的角膜组织中，JNK1的表达和磷酸化大大增加。JNK信号激活损害原发性角膜成纤维细胞的活力并促进其凋亡和自噬过程，以及Smad2 / 3磷酸化，TGFBI积累和Bcl-2抑制。自噬相关蛋白，如ATG5（自噬相关5），ATG12（自噬相关12）和LC3B（微管相关蛋白1轻链3 beta）也增加了经霉素或TGF-β1处理的角膜成纤维细胞。但是，SP600125有效逆转了由TGF-β1处理在角膜成纤维细胞中诱导的上述作用，包括TGF-β诱导的自噬进程。结果表明，JNK信号在GCD2角膜组织中被激活，并在GCD2发病过程中介导TGF-β诱导的TGFBI蛋白积累和角膜成纤维细胞凋亡。