The Role of IL-17A in Mediating Inflammatory Responses and Progression of Neurodegenerative Diseases.

IL-17A has been implicated as a critical pro-inflammatory cytokine in the pathogenesis of autoimmune and neurodegenerative disorders. Emerging evidence indicates its capacity to activate microglial cells and astrocytes, subsequently inducing the production of inflammatory mediators that exacerbate neuronal injury and functional impairment. Clinical observations have revealed a demonstrated association between IL-17A concentrations and blood-brain barrier (BBB) dysfunction, creating a pathological feedback loop that amplifies neuro-inflammatory responses. Recent advances highlight the cytokine's critical involvement in neurodegenerative disorders through multiple molecular pathways. Therapeutic interventions utilizing monoclonal antibodies (mAbs) against IL-17A or its cognate receptor (IL-17R) have shown promising clinical potential. This review systematically examines the IL-17A-mediated neuro-inflammatory cascades; the mechanistic contributions to neurodegenerative pathology in the established disease models including multiple sclerosis, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis; and current therapeutic strategies targeting the IL-17A signaling pathways. The analysis provides novel perspectives on optimizing cytokine-directed therapies while identifying the key challenges and research priorities for translational applications in neurodegeneration.