TNF and Parkinson disease: Only recently, a direct role for solTNF signaling in mediating the in vivo degeneration of DA neurons in both the 6-OHDA oxidative neurotoxin and chronic LPS models of PD has been demonstrated by the ability of dominant-negative (DN) TNF inhibitors or a lentivirus encoding DN-TNF to attenuate nigral DA neuron loss when delivered intranigrally [162,163].