TLR2 and Parkinson disease: In addition, the results of the comparison between the AAV-A53T and AAV-Cas9-TLR2, and the control group showed that the TLR2 knockdown did not completely reverse the vagus nerve dysfunction induced by α-synuclein, suggesting that the TLR2 inflammatory pathway may be one of the pathological mechanisms underlying AutD in the prodromal PD (Additional file 2: Fig. S5).