The Myelin and Lymphocyte Protein MAL Is Required for Binding and Activity of Clostridium perfringens ε-Toxin.

TitleThe Myelin and Lymphocyte Protein MAL Is Required for Binding and Activity of Clostridium perfringens ε-Toxin.
Publication TypeJournal Article
Year of Publication2015
AuthorsRumah KRashid, Ma Y, Linden JR, Oo MLin, Anrather J, Schaeren-Wiemers N, Alonso MA, Fischetti VA, McClain MS, Vartanian T
JournalPLoS Pathog
Date Published2015 May
KeywordsAnimals, Bacterial Toxins, Binding Sites, Cell Death, CHO Cells, Clostridium perfringens, Cricetulus, Humans, Injections, Intravenous, Ligands, Mice, Inbred C57BL, Mice, Knockout, Mutagenesis, Insertional, Myelin and Lymphocyte-Associated Proteolipid Proteins, Protein Interaction Domains and Motifs, Protein Precursors, Rats, Recombinant Fusion Proteins, Recombinant Proteins, Tissue Distribution, Toxicokinetics

Clostridium perfringens ε-toxin (ETX) is a potent pore-forming toxin responsible for a central nervous system (CNS) disease in ruminant animals with characteristics of blood-brain barrier (BBB) dysfunction and white matter injury. ETX has been proposed as a potential causative agent for Multiple Sclerosis (MS), a human disease that begins with BBB breakdown and injury to myelin forming cells of the CNS. The receptor for ETX is unknown. Here we show that both binding of ETX to mammalian cells and cytotoxicity requires the tetraspan proteolipid Myelin and Lymphocyte protein (MAL). While native Chinese Hamster Ovary (CHO) cells are resistant to ETX, exogenous expression of MAL in CHO cells confers both ETX binding and susceptibility to ETX-mediated cell death. Cells expressing rat MAL are ~100 times more sensitive to ETX than cells expressing similar levels of human MAL. Insertion of the FLAG sequence into the second extracellular loop of MAL abolishes ETX binding and cytotoxicity. ETX is known to bind specifically and with high affinity to intestinal epithelium, renal tubules, brain endothelial cells and myelin. We identify specific binding of ETX to these structures and additionally show binding to retinal microvasculature and the squamous epithelial cells of the sclera in wild-type mice. In contrast, there is a complete absence of ETX binding to tissues from MAL knockout (MAL-/-) mice. Furthermore, MAL-/- mice exhibit complete resistance to ETX at doses in excess of 1000 times the symptomatic dose for wild-type mice. We conclude that MAL is required for both ETX binding and cytotoxicity.

Alternate JournalPLoS Pathog.
PubMed ID25993478
PubMed Central IDPMC4439126
Grant ListT32 GM007739 / GM / NIGMS NIH HHS / United States