TH and Parkinson disease: By knocking out the TREM-1 gene we observed a significant increase in TH levels in SNpc (Fig. 5e, f) and striatal dopamine levels (Fig. 5g), this alteration notably alleviated motor dysfunction in PD model mice, as evidenced by their improved performance on behavioral tests including the OFT, pole test, and rotarod test (Fig. 5h–k).