Multiple sclerosis (MS), also known as disseminated sclerosis or encephalomyelitis disseminate, is an inflammatory disease in which myelin in the spinal cord and brain are damaged. IL-32α is known as a critical molecule in the pathophysiology of immune-mediated chronic inflammatory disease such as rheumatoid arthritis, chronic pulmonary disease, and cancers. However, the role of IL-32α on spinal cord injuries and demyelination is poorly understood. Recently, we reported that the release of proinflammatory cytokines were reduced in IL-32α-overexpressing transgenic mice. In this study, we investigated whether IL-32α plays a role on MS using experimental autoimmune encephalomyelitis (EAE), an experimental mouse model of MS, in human IL-32α Tg mice. The Tg mice were immunized with MOG35-55 suspended in CFA emulsion followed by pertussis toxin, and then EAE paralysis of mice was scored. We observed that the paralytic severity and neuropathology of EAE in IL-32α Tg mice were significantly decreased compared with that of non-Tg mice. The immune cells infiltration, astrocytes/microglials activation, and pro-inflammatory cytokines (IL-1β and IL-6) levels in spinal cord were suppressed in IL-32α Tg mice. Furthermore, NG2 and O4 were decreased in IL-32α Tg mice, indicating that spinal cord damaging was suppressed. In addition, in vitro assay also revealed that IL-32α has a preventive role against Con A stimulation which is evidenced by decrease in T cell proliferation and inflammatory cytokine levels in IL-32α overexpressed Jurkat cell. Taken together, our findings suggested that IL-32α may play a protective role in EAE by suppressing neuroinflammation in spinal cord.
Keywords: IL-32 alpha; Immune response; Immunity; Immunology and Microbiology Section; cytokines; experimental autoimmune encephalomyelitis; inflammation; multiple sclerosis.