Chen Yingying, Song Wei, Zhang He, Ji Xinping
Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Shenyang, 110022, China.
Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Shenyang, 110022, China.
Arch Biochem Biophys. 2023 Oct 1;747:109730. doi: 10.1016/j.abb.2023.109730. Epub 2023 Sep 9.
Epithelial-mesenchymal transition (EMT) of alveolar epithelial cells is a vital process in idiopathic pulmonary fibrosis (IPF), which results in the accumulation of fibroblasts and myofibroblasts and excessive extracellular matrix deposition. Based on RNA sequencing analysis and GEO dataset reanalysis, we screened out MICALL2, a gene upregulated in the lungs of IPF mice and alveolar epithelial type II (ATII) cells from IPF patients, and aimed to explore its role in IPF. We validated the expression of MICALL2 in bleomycin (BLM)-induced IPF mice and TGF-β1-stimulated ATII cells (primary murine ATII cells and A549 cells), and explored the role of MICALL2 in IPF by knockdown of MICALL2 in BLM-induced mice and TGF-β1-stimulated ATII cells. We found that MICALL2 was upregulated in the lungs of BLM-induced mice and TGF-β1-stimulated ATII cells. MICALL2-deficient mice had reduced fibrogenesis and restrained EMT upon BLM challenge. Knockdown of MICALL2 restrained the EMT process, in vitro, through impeding β-catenin nuclear translocation. Mechanistically, we demonstrated that NPAS2 is directly bound to the promoter of MICALL2. Altogether, our data revealed transactivation of MICALL2 induced by NPAS2, contributing to activation of the Wnt/β-catenin pathway in ATII cells, thus leading to the EMT process and subsequent pulmonary fibrosis. Interfering with MICALL2 may represent an innovative therapeutic target to mitigate the extent of IPF.
肺泡上皮细胞的上皮-间质转化（EMT）是特发性肺纤维化（IPF）中的一个重要过程，它导致成纤维细胞和肌成纤维细胞的积累以及细胞外基质的过度沉积。基于RNA测序分析和GEO数据集再分析，我们筛选出了MICALL2，这是一个在IPF小鼠肺组织以及IPF患者的II型肺泡上皮（ATII）细胞中上调的基因，并旨在探索其在IPF中的作用。我们验证了MICALL2在博来霉素（BLM）诱导的IPF小鼠和TGF-β1刺激的ATII细胞（原代小鼠ATII细胞和A549细胞）中的表达，并通过在BLM诱导的小鼠和TGF-β1刺激的ATII细胞中敲低MICALL2来探索其在IPF中的作用。我们发现MICALL2在BLM诱导的小鼠肺组织和TGF-β1刺激的ATII细胞中上调。MICALL2缺陷小鼠在受到BLM攻击后纤维化形成减少且EMT受到抑制。在体外，敲低MICALL2通过阻碍β-连环蛋白核转位来抑制EMT过程。从机制上来说，我们证明了NPAS2直接与MICALL2的启动子结合。总之，我们的数据揭示了NPAS2诱导的MICALL2反式激活，促进了ATII细胞中Wnt/β-连环蛋白信号通路的激活，从而导致EMT过程及随后的肺纤维化。干扰MICALL2可能是减轻IPF程度的一个创新性治疗靶点。
