TLR4 and Parkinson disease: They found that activation of TLR4 with an agonist in α-synuclein overexpressing mice increased uptake of α-synuclein by microglia, prevented neuronal degeneration and ameliorated motor deficits.306 In addition, gut microbial dysbiosis was suggested to alter TLR2 and TLR4 signaling, promoting α-synuclein aggregation in enteric and vagal neurons, which in turn migrates to the brain via peripheral nerves and contributes to neurodegeneration.307 These results provide a strong evidence for the involvement of gut microbial dysbiosis in PD development.