Genetic analysis of CNS autoimmunity using the diversity of the Collaborative Cross reveals unique phenotypes and mechanisms

Abstract

Multiple Sclerosis (MS) is a complex disease with remarkable heterogeneity in disease course and progression, the genetic basis of which remains obscure. Here we leveraged the Collaborative Cross (CC) - a highly genetically diverse mouse strain panel - and myelin oligodendrocyte glycoprotein peptide 35–55 (MOG35–55) induced experimental autoimmune encephalomyelitis (EAE), to model genetics of MS disease course. 33 CC strains were selected based on compatible MHC haplotypes (H2b and H2g7), which captured a wide spectrum of distinct EAE phenotypes, compared with typical chronic EAE in C57BL/6 mice. CC028 mice exhibited severe and rapidly progressing disease. In contrast, several strains, including CC011 and CC040, were highly resistant to EAE. Sex differences in EAE course were observed in 4 strains, including CC042. Remitting-relapsing EAE was observed in 4 strains, including CC002. In addition to classical EAE clinical signs (ascending paralysis), we identified two strains, CC004 and CC083 that exhibited high incidence of axial rotary (AR)-EAE, including profound ataxia, head tilt, and axial rotation. Preliminary quantitative trait locus (QTL) analysis revealed a distinct linkage pattern in each sex for classical EAE severity, with several emerging peaks on chromosome (Chr) 2, 8, 12, 18, and X in females, Chr10 in males, and Chr4 in both sexes. QTL analysis of AR-EAE severity revealed a narrow interval on Chr18 (39.2–41.0Mb) passing suggestive linkage significance at the 90% confidence threshold. Experiments are ongoing to determine the immunopathologic basis of distinct genetically controlled EAE phenotypes in CC strains of interest. Supported by grants from NIH (R21 AI145306-01) and the National MS Society (RG-1901-33309)