Lung endothelial cells are sensitive to epsilon toxin from Clostridium perfringens

Abstract

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.

The MAL Protein, an Integral Component of Specialized Membranes, in Normal Cells and Cancer

“…However, a humanized zebrafish model expressing human MAL in endothelial cells binds to ETX and responds by producing blood–brain barrier leakage, blood vessel stenosis, perivascular edema and blood stasis [ 157 ]. In mice, MAL expression was found in the endothelium of some lung vessels, supporting the hypothesis that MAL is a key element in the ETX-induced perivascular edema in the lungs [ 158 ]. ETX binding is clearly observed in the microvasculature of the central nervous system but not in the vasculature of peripheral organs in the mouse, indicating that ETX specifically targets the endothelial cells of the CNS.…”

Bifidobacterium animalis subsp. lactis BL-99 ameliorates colitis-related lung injury in mice by modulating short-chain fatty acid production and inflammatory monocytes/macrophages

“…38 This bacterial species was equipped to produce the pore-forming protein epsilon toxin, which therefore alters intestinal permeability and enters the intestinal vascular system. 39,40 Herein, we also found that these three bacteria were significantly increased in colitis mice with lung injury, whereas BL-99 inhibited their growth in the intestine.…”

CNS endothelial derived extracellular vesicles are biomarkers of active disease in multiple sclerosis

“…Several publications have demonstrated that knock out of MAL expression in pETX sensitive organisms or cell lines totally abolishes pETX binding and/or toxicity while exogenous expression of MAL confers pETX binding in normally resistant cells or organisms [ 62 , 97 , 98 , 126 – 129 ]. In addition, the specificity of pETX for MAL is supported by descriptive studies that strongly correlate pETX binding to MAL expression in multiple sensitive cell lines [ 130 – 132 ]. Finally, direct protein–protein interaction between pETX and MAL have been published by two independent groups via immunoprecipitation and affinity purification column [ 126 , 129 ].…”

“…To detect EV MAL expression, we utilized binding of the MAL-specific ligand, pETX [ 98 , 126 ], as there is no currently available anti-MAL antibody suitable for flow cytometry. This ligand was selected based on numerous, independent studies that strongly indicate MAL is the receptor for pETX [ 62 , 97 , 98 , 126 – 132 ]. MAL has been repeatedly demonstrated by independent groups to be both necessary and sufficient for pETX binding [ 62 , 97 , 98 , 126 – 129 ].…”