Fig. 2.

Microglia-mediated neuroinflammation and neuroprotective mechanisms in PD pathogenesis. Microglia become an activated M1 phenotype when exposed to PD pathological conditions like misfolded proteins and pro-inflammatory factors. M1 microglia secrete pro-inflammatory factors that further induces neuroinflammatory and neurotoxic mechanisms in the human brain through process such as enhanced phagocytotic activity and increased ROS production. On the other hand, the presence and stimulation by anti-inflammatory factors can lead to an activated M2 phenotype. Neuroprotective mechanisms in PD from M2 microglia include the release of anti-inflammatory cytokines into the brain which inhibits continued neuroinflammation