For example, TGFβ1, which has been shown to inhibit microglial inflammatory responses in a rat model of PD (Chen S. et al., 2017), and matrix metallopeptidase 2 (MMP2), which has been shown to degrade α-synuclein aggregates (Oh et al., 2017), were found to be down-regulated in LRRK2-G2019S astrocytes derived from patient-induced pluripotent stem cells (iPSC) (Booth et al., 2019). Here, MMP2 is linked to Parkinson disease.