TLR4 and Parkinson disease: Through cathepsin-D-dependent regulation of the Toll-like receptor 4 (TLR4) signaling pathway, oxymatrine significantly attenuates 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's diseases, and this provides dopamine-based neuroprotection and reduces microglia-mediated neuroinflammation [120].