Instead, upon binding to peripheral MC1R, it protects dopaminergic neurons via the CREB/Nr4a1/NF-κB pathway (abbreviations: cAMP response element-binding protein/nuclear receptor subfamily 4 group A member 1/nuclear factor kappa B), mitigating PD neuroinflammation, meaning less circulating TNF-α, IL-1β, monocytes and cytotoxic CD8+ T cells [62,66]. The gene discussed is NR4A1; the disease is Parkinson disease.