IL-32 通过触发 A549 细胞内质网应激诱导上皮-间充质转化。

IL-32 induces epithelial-mesenchymal transition by triggering endoplasmic reticulum stress in A549 cells.

机构信息

The First Clinical Medical College, Jinan University, 601 W. Huangpu Avenue, Guangzhou, 510630, China.

Department of Respiratory Medicine, The Third Affiliated Hospital of Zunyi Medical University (The First People's Hospital of Zunyi), Zunyi, 563000, Guizhou, China.

出版信息

BMC Pulm Med. 2020 Oct 23;20(1):278. doi: 10.1186/s12890-020-01319-z.

BACKGROUND

Epithelial-mesenchymal transition (EMT) is a key process in the onset and development of idiopathic pulmonary fibrosis (IPF) with unclear mechanisms. Our previous studies found that bleomycin and tunicamycin could induce ER stress and consequently trigger EMT accompanying with IL-32 overexpression. This study was aimed to investigate the effects of IL-32 on EMT and ER stress to elucidate the pathogenesis of IPF.

METHODS

Human lung adenocarcinoma A549 cells were treated with recombinant human (rh)IL-32, IL-32 siRNA and EMT inducer tunicamycin, or 4-phenylbutyric acid (4-PBA), respectively. Then the cell morphology was observed and the expression of ER-related markers and EMT-related markers were detected by RT-qPCR or western blotting.

RESULTS

Stimulation of A549 cells with rhIL-32 led to a morphological change from a pebble-like shape to an elongated shape in a portion of the cells, accompanied by down regulated expression of the epithelial cell marker E-cadherin and up regulated expression of the mesenchymal cell markers N-cadherin, Vimentin, and Zeb-1. However, these rhIL-32 induced changes were inhibited by the ER stress inhibitor 4-PBA. Suppression of IL-32 expression with siRNA inhibited TM-induced EMT. Further stimulation of the A549 cells with rhIL-32 demonstrated an increase in the expression of GRP78, although this increase was also inhibited by 4-PBA.

CONCLUSIONS

These results suggest that IL-32 induces EMT in A549 cells by triggering ER stress, and IL-32 may be a novel marker for IPF.

背景

上皮-间充质转化（EMT）是特发性肺纤维化（IPF）发生和发展的关键过程，其机制尚不清楚。我们之前的研究发现博来霉素和衣霉素可诱导内质网应激，从而触发 EMT 并伴随着 IL-32 的过表达。本研究旨在探讨 IL-32 对 EMT 和内质网应激的影响，以阐明 IPF 的发病机制。

方法

用重组人（rh）IL-32、IL-32 siRNA 和 EMT 诱导剂衣霉素或 4-苯丁酸（4-PBA）分别处理人肺腺癌细胞 A549。然后观察细胞形态，并用 RT-qPCR 或 Western blot 检测 ER 相关标志物和 EMT 相关标志物的表达。

结果

rhIL-32 刺激 A549 细胞可导致部分细胞形态从鹅卵石状变为长形，同时上皮细胞标志物 E-钙黏蛋白表达下调，间充质细胞标志物 N-钙黏蛋白、波形蛋白和 Zeb-1 表达上调。然而，这些 rhIL-32 诱导的变化可被内质网应激抑制剂 4-PBA 抑制。用 siRNA 抑制 IL-32 表达可抑制 TM 诱导的 EMT。进一步用 rhIL-32 刺激 A549 细胞，GRP78 的表达增加，而这一增加也可被 4-PBA 抑制。