These proteases from mast cells could activate Protease-activated receptor-2 (PAR-2) that is expressed in neuronal and glial cells and is involved in the development and progression of PD and upregulate neuroinflammation (Liu et al., 2014; Kempuraj et al., 2019; Widera et al., 2019). Here, F2RL1 is linked to Parkinson disease.