Loss of MBD2 ameliorates LPS-induced alveolar epithelial cell apoptosis and ALI in mice via modulating intracellular zinc homeostasis
Loss of MBD2 ameliorates LPS-induced alveolar epithelial cell apoptosis and ALI in mice via modulating intracellular zinc homeostasis
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MBD2 缺失通过调节细胞内锌稳态改善 LPS 诱导的小鼠肺泡上皮细胞凋亡和 ALI
DOI：
10.1096/fj.202100924rr
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发表时间：
2022-02-01
期刊：
影响因子：
4.8
通讯作者：
Xiao, Bing
中科院分区：
文献类型：
--
作者：
Liu, Jiqiang;Yao, Shuo;Xiao, Bing
肺泡上皮细胞凋亡是急性肺损伤（acute lung injury，ALI）发病的重要起始环节，近年来研究发现甲基化CpG结合域蛋白2（Methyl-CpG binding domain protein 2，MBD 2）参与了肺泡上皮细胞凋亡的发生，但其在ALI中的作用尚不清楚。本研究旨在探讨MBD 2在ALI发病中的作用及其机制。我们发现MBD 2的表达在LPS处理的小鼠肺泡上皮细胞中与凋亡平行地增加，MBD 2的敲除减少凋亡并保护小鼠免受LPS诱导的ALI。在小鼠肺泡上皮细胞系MLE-12细胞中，LPS以剂量和时间依赖性方式诱导MBD 2表达和凋亡。MBD 2的shRNA敲减减轻，而MBD 2的过表达增加LPS诱导的细胞凋亡。机制上，当用LPS处理MLE-12细胞时，细胞内锌水平降低。MBD 2基因敲低可恢复LPS诱导的细胞内锌水平，而MBD 2基因过表达可进一步加重LPS诱导的细胞内锌丢失。金属转录因子1（metaltranscriptionfactor 1，MTF 1）是一种重要的转录因子，负责细胞内锌的外排。LPS处理在体内和体外均诱导MTF 1表达。抑制MTF 1可减少LPS诱导的MLE-12细胞凋亡。MBD 2可与MTF 1的启动子区结合，促进MTF 1的表达。总的来说，这些数据表明，MBD 2的损失通过上调MTF 1调节细胞内锌稳态来改善LPS诱导的小鼠肺泡上皮细胞凋亡和ALI。
Apoptosis of alveolar epithelial cells is a critical initial link in the pathogenesis of acute lung injury (ALI), recent studies have revealed that Methyl-CpG binding domain protein 2 (MBD2) was involved in the execution of apoptosis, yet its role in ALI remained unclear. In the present study, we aim to explore the role and mechanism of MBD2 in the pathogenesis of ALI. We have found that MBD2 expression, in parallel to apoptosis, increased in alveolar epithelial cells of mice treated with LPS, knockout of MBD2 reduced apoptosis and protected mice from LPS-induced ALI. In MLE-12 cells, a cell line of murine alveolar epithelial cells, LPS induced MBD2 expression and apoptosis in a dose- and time-dependent manner. Knockdown of MBD2 with shRNA alleviated, while overexpression of MBD2 increased LPS-induced apoptosis. Mechanistically, intracellular zinc level decreased when MLE-12 cells were treated with LPS. MBD2 knockdown restored intracellular zinc level after LPS treatment, and MBD2 overexpression further aggravated LPS-induced intracellular zinc loss. Metal transcription factor 1 (MTF1) is a critical transcription factor in charge of intracellular zinc efflux. LPS treatment induced MTF1 expression both in vivo and in vitro. Inhibition of MTF1 reduced LPS-induced apoptosis in MLE-12 cells. MBD2 could bind to the promoter region of MTF1 and promote MTF1 expression. Collectively, these data indicated that loss of MBD2-ameliorated LPS-induced alveolar epithelial cell apoptosis and ALI in mice via modulating intracellular zinc homeostasis by upregulating MTF1.