Epsilon toxin from Clostridium perfringens induces toxic effects on skin tissues and HaCaT and human epidermal keratinocytes

Epsilon toxin (ETX) is a key pathogenic factor of C. perfringens type B and D, causing fatal enterotoxemia in sheep and goats. Excessive production of ETX increases intestinal permeability; its entrance into the bloodstream leads to severe edema in organs such as the brain and kidneys. At present, very few cell lines are known to be sensitive to ETX, with the most sensitive cell model for in vitro research being the MDCK cell line. Recently, more tissue-derived cell lines have been shown to be sensitive to ETX, but the mechanism of cytotoxicity remains unknown. Herein, for the first time, we aimed to evaluate the effects of ETX on HaCaT keratinocytes and human epidermal keratinocytes (HEKa). In addition, the median lethal dose of subcutaneous injection of ETX in mice was 109 ng/kg. At this dose, ETX rapidly entered the blood circulation, causing hemorrhage and edema in the brain and kidneys. ETX also increased the expression of aquaporin 3 in the muscle layer and hair follicles of the skin. We further showed the presence of the MAL protein in HaCaT keratinocytes and HEKa and skin tissues, supporting the hypothesis that it is a key element in the mechanism of cytotoxicity of ETX. In conclusion, skin cell lines were used for the first time as a model for studying the toxic effects of ETX, which will help elucidate the cytotoxicity induced by ETX and the related molecular mechanisms.