Localization of TLR4 in wild-type and hSOD1G93A mice at end-stage of disease. (A-R) Double immunolabelling of TLR4 (red) with cellular markers (green) for motor neurons (ChAT; (A-C) wild-type (WT) mice, (J-L) hSOD1G93A mice), microglia (Iba-1; (D-F) WT mice, (M-O) hSOD1G93A mice), and astrocytes (GFAP; (G-I) WT mice, (P-R) for hSOD1G93A mice) in the ventral lumbar spinal cord of WT and hSOD1G93A mice at end-stage of disease. TLR4 was mainly co-localised with ChAT-positive motor neurons in the WT mice (A, C, white arrow) with minimal co-localisation with Iba-1-labelled microglia and GFAP-positive astrocytes (F, I). In hSOD1G93A mice, TLR4 immunolabelling was evident on ChAT positive motor neurons and GFAP-positive astrocytes with some localisation with Iba-1-labelled microglia (white arrows in J, L, M, O, P, R). Scale bars for all panels = 10 μm. TLR4 = toll-like receptor 4; ChAT = choline acetyltransferase; Iba-1 = ionised calcium-binding adapter molecule-1; GFAP = glial fibrillary acidic protein.