Gene expression of CSF1R and its cognate ligands in the brain of PD patients and animal models of PD. Human gene expression of CSF1R (A), and CSF-1 (B) were both increased in the SN of PD patients (n = 22 males and 9 females) compared to age-matched controls (n = 10 males and 7 females), whereas IL-34 gene expression showed no difference (C). GEO numbers were normalized to 1 to generate relative expression values and allow comparison between datasets. D, Mice received LPS treatment (1 mg/kg) once daily for 4 days and sacrificed 1 or 14 days after the last injection. Quantitative PCR measurement of Csf1r, Csf-1, and Il-34 mRNA expression levels in the striatum of LPS-treated mice. E, Mice were treated with an acute MPTP paradigm and sacrificed 2 days or 7 days following the MPTP injections. Quantitative PCR measurements of Csf1r, Csf-1, and Il-34 mRNA expression levels in the striatum of MPTP-treated mice. Data are represented as mean ± SEM, *P < .05, **P < .01, ns = not statistically significant P > .05