Lung endothelial cells are sensitive to epsilon toxin from Clostridium perfringens

The pore-forming protein epsilon toxin (Etx) from Clostridium perfringens produces acute perivascular edema affecting several organs, especially the brain and lungs. Despite the toxin evident effect on microvasculature and endothelial cells, the underlying molecular and cellular mechanisms remain obscure. Moreover, no Etx-sensitive endothelial cell model has been identified to date. Here, we characterize the mouse lung endothelial cell line 1G11 as an Etx-sensitive cell line and compare it with the well-characterized Etx-sensitive Madin-Darby canine kidney epithelial cell line. Several experimental approaches, including morphological and cytotoxic assays, clearly demonstrate that the 1G11 cell line is highly sensitive to Etx and show the specific binding, oligomerization, and pore-forming activity of the toxin in these cells. Recently, the myelin and lymphocyte (MAL) protein has been postulated as a putative receptor for Etx. Here, we show the presence of Mal mRNA in the 1G11 cell line and the presence of the MAL protein in the endothelium of some mouse lung vessels, supporting the hypothesis that this protein is a key element in the Etx intoxication pathway. The existence of an Etx-sensitive cell line of endothelial origin would help shed light on the cellular and molecular mechanisms underlying Etx-induced edema and its consequences.