TLR4 and Parkinson disease: Consistent with increases in both pKr-2 (Fig. 2a–c) and microglial TLR4 (Fig. 1c,d) in the SN of patients with PD, pKr-2 treatment increased microglial TLR4 in cultures of the BV-2 microglial cell line (Fig. 4a) and the SN of rat brains (Fig. 4b,c).