Fig. 4

Microglia and T cells reciprocally regulate inflammation in PD. Neuroprotective microglia can induce the differentiation of naïve T cells to Th2 and Treg cells by secreting cytokines IL-4 and TGF-β. Meanwhile, chemokines CCL1, CCL17, CCL22, CCL24, and CCL18 released from neuroprotective microglia can bind to CCR4, CCR8, and PITPNM3 on the surface of Th2 and Treg cells, further increasing cell activation, anti-inflammatory cytokine release, and migration. Notably, anti-inflammatory cytokines released by Th2 and Treg cells can increase the number of neuroprotective microglia and inhibit the function of neurotoxic microglia. In conclusion, the interaction between neuroprotective microglia and anti-inflammatory T cell subtypes in PD increases the number and function of anti-inflammatory-type cells. At the same time, cellular interactions reduced the number and function of pro-inflammatory-type cells, thereby regulating the inflammatory state in the microenvironment and further protecting neurons from damage