Epsilon Toxin-Producing Clostridium perfringens within the MS Gut Microbiome and Epsilon Toxin Function on Immune Privilege

Multiple Sclerosis (MS) is a complex disease of the CNS believed to require one or more environmental triggers and is characterized by episodic formation of inflammatory demyelinating lesions in the brain and spinal cord. Gut dysbiosis is a common feature in MS and here, using enhanced and quantitative PCR detection, we show that people with MS are more likely to harbor and have higher abundance of epsilon toxin (ETX)-producing strains of Clostridium perfringens within their gut microbiome compared to healthy controls (HC). MS patient-derived isolates produce functional ETX and have a genetic architecture typical of highly conjugative plasmids. In the active immunization model of experimental autoimmune encephalomyelitis (EAE), where pertussis toxin (PTX) is used to overcome CNS immune privilege, we find that ETX can substitute for PTX in disease induction. In contrast to PTX-induced EAE, where inflammatory demyelination is largely restricted to the spinal cord, ETX-induced EAE results in multifocal demyelination in the corpus callosum, thalamus, cerebellum, brainstem, and spinal cord, more akin to the lesion distribution observed in MS. Transcriptional profiles from CNS endothelial cells reveal ETX-induced genes that are known to play a role in overcoming CNS immune privilege. Together, these findings support ETX-producing strains of C. perfringens as biologically plausible pathogens in MS to trigger inflammatory demyelination in the context of circulating myelin autoreactive lymphocytes. Overall design: Comparative gene expression profiling analysis of RNA-seq data of CNS endothelial cells treated with PBS, ETX (0.5 µg/kg b.w.), or PTX (5 µg/kg b.w).