肿瘤坏死因子-α(TNF-α)是参与全身性炎症的细胞因子。TNF-α减缓成骨分化,这可能导致炎症微环境中骨骼发育不良。TNF-α通过激活JAK-STAT3通路抑制成骨分化,其中信号转导和转录激活因子3(STAT3)相互作用蛋白1(StIP1,也称为延伸复合物蛋白2,ELP2)是JAK-STAT3途径中的关键蛋白。我们研究了在成骨细胞分化过程中,ELP2激活是否以及如何介导TNF-α诱导的焦亡。使用前成骨细胞MC3T3-E1细胞的体外细胞培养,我们发现,在成骨细胞分化过程中,TNF-α暴露会导致炎症微环境中的细胞焦亡.生物信息学,蛋白质对接模型和免疫共沉淀分析显示ELP2、STAT3和NLRP3之间存在关联。强制ELP2表达促进MC3T3-E1细胞的焦亡,随着STAT3,NLRP3炎性体表达的增加,GSDMD/GSDME,成骨细胞标记基因,和碱性磷酸酶的活性。相比之下,ELP2沉默改善MC3T3-E1细胞的焦亡,和成骨分化,特别是在TNF-α刺激后。因此,在成骨细胞分化过程中TNF-α诱导的细胞焦亡是由ELP2介导的。这些结果表明,ELP2在MC3T3-E1细胞的焦亡中上调,并通过NLRP3-GSDMD/GSDME激活抑制对TNF-α的成骨分化。
Tumour necrosis factor-α (TNF-α) is a cytokine involved in systemic inflammation. TNF-α slows down osteogenic differentiation, which may contribute to poor bone development in the inflammatory microenvironment. TNF-α inhibits osteogenic differentiation by activating the JAK-STAT3 pathway, of which Signal transducer and activator of transcription 3 (STAT3)-interacting protein 1 (StIP1, also known as elongator complex protein 2, ELP2) is a key protein in the JAK-STAT3 pathway. We investigated whether and how ELP2 activation mediates the TNF-α-induced pyroptosis during osteoblastic differentiation. Using in vitro cell cultures of preosteoblastic MC3T3-E1 cells, we found that TNF-α exposure causes cell pyroptosis in an inflammatory microenvironment during osteoblastic differentiation. Bioinformatics, protein docking model and co-immunoprecipitation analysis revealed an association between ELP2, STAT3 and NLRP3. Forced ELP2 expression promoted MC3T3-E1 cells pyroptosis, with an increase in the expression of STAT3, NLRP3 inflammasome, GSDMD/GSDME, osteoblast marker genes, and the activity of alkaline phosphatase. In contrast, ELP2 silencing ameliorated MC3T3-E1 cells pyroptosis, and osteogenic differentiation, especially after TNF-α stimulation. The TNF-α-induced cells pyroptosis during osteoblastic differentiation was therefore mediated by ELP2. These results suggest that ELP2 is upregulated at the pyroptosis of MC3T3-E1 cells and inhibits osteogenic differentiation in response to TNF-α through NLRP3-GSDMD/GSDME activation.