Loss of MBD2 ameliorates LPS-induced alveolar epithelial cell apoptosis and ALI in mice via modulating intracellular zinc homeostasis.

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.

Liu J ，Yao S ，Jia J ，Chen Z ，Yuan Y ，He Y ，Wasti B ，Duan W ，Li D ，Wang G ，Jia A ，Sun W ，Qiu S ，Ma L ，Li J ，Liu Y ，Zheng J ，Xiang X ，Zhang X ，Liu S ，He Z ，Peng Z ，Zhang H ，Zhang D ，Xiao B ... -  《-》

Inhibition of METTL3 alleviated LPS-induced alveolar epithelial cell apoptosis and acute lung injury via restoring neprilysin expression.

To investigate the role and mechanisms of methyltransferase-like 3 (METTL3) in the pathogenesis of lipopolysaccharide (LPS)-induced acute lung injury (ALI). LPS intratracheally instillation was applied in alveolar epithelial cell METTL3 conditional knockout (METTL3-CKO) mice and their wild-type littermates. In addition, METTL3 inhibitor STM2457 was used. LPS treatment on mouse lung epithelial 12 (MLE-12) cell was applied to establish an in vitro model of LPS-induced ALI. H&E staining, lung wet-to-dry ratio, and total broncho-alveolar lavage fluid (BALF) concentrations were used to evaluate lung injury. Overall, the m6A level was determined with the m6A RNA Methylation Quantification Kit and dot blot assay. Expression of METTL3 and neprilysin were measured with immunohistochemistry, immunofluorescence, immunofluorescence-fluorescence in situ hybridization, and western blot. Apoptosis was detected with TUNEL, western blot, and flow cytometry. The interaction of METTL3 and neprilysin was determined with RIP-qPCR and MeRIP. METTL3 expression and apoptosis were increased in alveolar epithelial cells of mice treated with LPS, and METTL3-CKO or METTL3 inhibitor STM2457 could alleviate apoptosis and LPS-induced ALI. In MLE-12 cells, LPS-Induced METTL3 expression and apoptosis. Knockdown of METTL3 alleviated, while overexpression of METTL3 exacerbated LPS-induced apoptosis. LPS treatment reduced neprilysin expression, the intervention of neprilysin expression negatively regulated apoptosis without affecting METTL3 expression, and mitigated the promoting effect of METTL3 on LPS-induced apoptosis. Additionally, METTL3 could bind to the mRNA of neprilysin, and reduce its expression. Our findings revealed that inhibition of METTL3 could exert anti-apoptosis and ALI-protective effects via restoring neprilysin expression.

Jia J ，Yuan Y ，He Y ，Wasti B ，Duan W ，Chen Z ，Li D ，Sun W ，Zeng Q ，Ma L ，Zhang X ，Liu S ，Zhang D ，Liu L ，Liu Q ，Liang H ，Wang G ，Xiang X ，Xiao B ... -  《-》

FTO Deficiency Alleviates LPS-induced Acute Lung Injury by TXNIP/NLRP3-mediated Alveolar Epithelial Cell Pyroptosis.

Xie WM ，Su W ，Liu XY ，Zhou J ，Wang M ，Wang Y ，Wang W ，Bai X ，Li Z ，Li T ... -  《-》

Impairment of Fatty Acid Oxidation in Alveolar Epithelial Cells Mediates Acute Lung Injury.

Cui H ，Xie N ，Banerjee S ，Ge J ，Guo S ，Liu G ... -  《-》

MBD2 upregulates miR-301a-5p to induce kidney cell apoptosis during vancomycin-induced AKI.

Wang J ，Li H ，Qiu S ，Dong Z ，Xiang X ，Zhang D ... -  《Cell Death & Disease》