Autophagy regulates TNFα-mediated joint destruction in experimental arthritis
Autophagy regulates TNFα-mediated joint destruction in experimental arthritis
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DOI：
10.1136/annrheumdis-2012-201671
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发表时间：
2013-05-01
影响因子：
27.4
通讯作者：
Distler, Joerg H. W.
中科院分区：
文献类型：
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作者：
Lin, Neng-Yu;Beyer, Christian;Distler, Joerg H. W.
目的自噬是一种体内平衡的过程，以回收不必要的和受损的细胞器。近来，自噬途径的失调被认为与多种疾病的发病机制有关。在此，我们探讨了自噬在关节炎关节破坏中的作用。方法用透射电子显微镜、Western blotting和免疫组织化学方法分析体外和体外破骨细胞自噬的Beclin1和ATG7的表达。小分子抑制剂、LysMCre介导的ATG7基因敲除和慢病毒过表达Beclin1在体内外被用来调节自噬。实时荧光定量检测破骨细胞分化标志物。结果人类风湿关节炎(RA)破骨细胞自噬激活，Beclin1和ATG7表达增强。在体内外，肿瘤坏死因子α均能有效地诱导自噬相关基因的表达并激活自噬。通过过表达Beclin1激活自噬，诱导破骨细胞生成，增强培养的破骨细胞的吸收能力，而药物或遗传失活的自噬阻止破骨细胞分化。移植ATG7(fl/fl)xLysMCre(+)骨髓细胞(BMC)的关节炎性hTNFαTG小鼠破骨细胞数量减少，可保护骨侵蚀、蛋白多糖丢失和软骨细胞死亡。结论RA中的自噬是以依赖于TNFα的方式激活的，并调节破骨细胞分化和骨吸收。因此我们提供了证据
Objectives Autophagy is a homeostatic process to recycle dispensable and damaged cell organelles. Dysregulation of autophagic pathways has recently been implicated in the pathogenesis of various diseases. Here, we investigated the role of autophagy during joint destruction in arthritis.Methods Autophagy in osteoclasts was analysed in vitro and ex vivo by transmission electron microscopy, Western blotting and immunohistochemistry for Beclin1 and Atg7. Small molecule inhibitors, LysMCre-mediated knockout of Atg7 and lentiviral overexpression of Beclin1 were used to modulate autophagy in vitro and in vivo. Osteoclast differentiation markers were quantified by real-time PCR. The extent of bone and cartilage destruction was analysed in human tumour necrosis factor alpha transgenic (hTNF alpha tg) mice after adoptive transfer with myeloid specific Atg7-deficient bone marrow.Results Autophagy was activated in osteoclasts of human rheumatoid arthritis (RA) showing increased expression of Beclin1 and Atg7. TNF alpha potently induced the expression of autophagy-related genes and activated autophagy in vitro and in vivo. Activation of autophagy by overexpression of Beclin1-induced osteoclastogenesis and enhanced the resorptive capacity of cultured osteoclasts, whereas pharmacologic or genetic inactivation of autophagy prevented osteoclast differentiation. Arthritic hTNF alpha tg mice transplanted with Atg7(fl/fl)xLysMCre(+) bone marrow cells (BMC) showed reduced numbers of osteoclasts and were protected from TNF alpha-induced bone erosion, proteoglycan loss and chondrocyte death.Conclusions These findings demonstrate that autophagy is activated in RA in a TNF alpha-dependent manner and regulates osteoclast differentiation and bone resorption. We thus provide evidence