CMIT/MIT induce apoptosis and inflammation in alveolar epithelial cells through p38/JNK/ERK1/2 signaling pathway

• DOI: 10.1007/s13273-019-0005-0
• Publication Date: 2018-12-28T03:45:20Z
• Authors: Jooyeon Lee; Hanbyeol Lee; Soojin Jang; Seok-Ho Hong; Woo Jin Kim; Se Min Ryu; Sung-Min Park; Kyung-Hak Lee; Sung-Joon Cho; Se-Ran Yang
• Keywords: 0303 health sciences; 03 medical and health sciences; 3. Good health

The 5-chloro-2-methyl-2h-isothiazolin-3-one and 2-methyl-2h-isothiazol-3-one (CMIT/MIT) are widespread biocides that commonly found in variety of water-soluble consumer products including dentifrice, germicide and shampoo etc. Recently, in Korea, it has been reported that general population was exposed to humidifier sterilizer with CMIT/MIT as disinfectant components, and eventually more than 530 victims had been suffered severe lung disease since they had used. Although it is known to be a certain risk factor threatening public health, it is unknown to be associated with pathological cellular- and molecular-mechanisms. Therefore, in this study, we investigated the cytotoxic effect of CMIT/MIT in mouse alveolar type II epithelial cells, MLE-12 cells. MLE-12 cells were treated with CMIT/MIT (0-50 μM) for 24 hours. In MTT assay, cellular proliferation was significantly decreased in response to CMIT/MIT treatment. In western blot analysis, protein levels of BAX/Bcl-2 and cleaved caspase-3 were significantly increased. Moreover, cell cycle-related gene were also increased. In ELISA, CMIT/MIT increased the release of pro-inflammatory cytokine of TNF-α and IL-1β. Moreover, CMIT/MIT increased the phosphorylated-ERK1/2, phosphorylated-p38, and phosphorylated-JNK1/2 protein levels in MLE-12 cells. These findings suggest that CMIT/MIT exposure induce the injury of alveolar epithelial cells with inflammatory response via the p38-JNK1/2-ERK1/2 signaling pathway.