Cytotoxic effects of cigarette smoke are thought to be causes of cigarette smoking-related diseases such as respiratory infection, chronic obstructive pulmonary disease, and atherosclerosis. Unsaturated carbonyl compounds are major cytotoxic factors in the gas phase of cigarette smoke. Cell death induced by unsaturated carbonyl compounds in cigarette smoke is PKC-dependent ferroptosis. Although the cell sensitivity to unsaturated carbonyl compounds varies by cell types, the molecular mechanisms underlying this sensitivity remain unclear. In this study, we have examined the factors involved in determining sensitivity to unsaturated carbonyl compounds. We found that two mouse macrophage cell lines exhibited different sensitivities; J774.1 macrophages were sensitive to unsaturated carbonyl compounds, whereas RAW264.7 macrophages were resistant. Glutathione synthesis inhibitor increased the sensitivity of RAW264.7 macrophages to unsaturated carbonyl compounds. Quantitative RT-PCR revealed that the expression level of the cystine transporter SLC7A11 was higher in RAW264.7 macrophages than in J774.1 macrophages. Inhibition of SLC7A11 activity increased sensitivity to unsaturated carbonyl compounds, while overexpression of SLC7A11 enhances resistance to these compounds. The current results suggest that the SLC7A11 level is a key factor in determining the macrophage sensitivity to unsaturated carbonyl compounds.
