TLR4 and Parkinson disease: Recently, we have demonstrated that TLR4-deficient mice are less vulnerable to MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) intoxication than wild-type mice and display a decreased number of Iba1+ and MHC II+ activated microglial cells after MPTP application, suggesting that the TLR4 pathway is involved in experimental PD.