Differential roles of M1 and M2 microglia in Parkinson’s disease: a critical narrative review

Abstract

Parkinson's disease (PD) is marked by the selective loss of dopaminergic neurons, leading to debilitating motor and non-motor symptoms. Central to PD pathogenesis is the intricate involvement of microglia, the resident immune cells of the brain. This narrative review delves into the distinct functions of M1 and M2 microglia in the context of PD. M1 microglia exhibit pro-inflammatory characteristics, releasing cytotoxic factors that exacerbate neuronal damage. In contrast, M2 microglia contribute to neuroprotection by secreting anti-inflammatory cytokines and participating in the clearance of cellular debris. The dynamic interplay between these microglial phenotypes is explored, providing insights into their roles in disease progression. Emerging therapeutic strategies aimed at modulating microglial polarization are discussed, emphasizing their potential in PD intervention. By unraveling the nuanced contributions of M1 and M2 microglia in PD, this review not only advances our understanding of neuroinflammatory mechanisms but also underscores the importance of targeted interventions to alleviate disease-associated pathology and preserve neuronal integrity in Parkinson's disease.