Expression and localisation of C1q in hSOD1G93Aand wild-type mice during disease progression. (A) mRNA expression profile of C1qB in lumbar spinal cord of hSOD1G93A mice relative to wild-type (WT) mice. Dashed line, baseline expression in WT controls at each time point. (B) Degree of immunolabelling for C1q significantly increased in the lumbar spinal cord of hSOD1G93A mice at end stage when compared with WT mice. (A, B) Data expressed as mean ± standard error of the mean (n = 6 mice/group; *P <0.05, **P <0.01, ***P <0.001, Student t test). (C) to (T) Double immunolabelling of C1q (red) with cellular markers (green) for motor neurons (ChAT; (C) to (E) WT mice, (L) to (N) hSOD1G93A mice), astrocyte (glial fibrillary acidic protein (GFAP); (F) to (H) WT mice, (O) to (Q) hSOD1G93A mice), and microglia (Iba-1; (I) to (K) WT mice, (R) to (T) hSOD1G93A mice) in the ventral lumbar spinal cord of WT and hSOD1G93A mice (end stage). There was minimal expression of C1q in WT (C, F and I) with marked increase in hSOD1G93A mice (L, O and R). In hSOD1G93A mice, C1q was co-localised with ChAT-positive motor neurons (white arrows in (L) and (N) (detailed in U)). There was little to no co-localisation of C1q with GFAP-positive astrocytes (Q (detailed in V)), and minimal co-localisation with Iba-1-labelled microglia (white arrows in R and T (detailed in W)). PS, pre-symptomatic; OS, onset; MS, mid-symptomatic; ES, end-stage. Scale bar for all panels = 20 μm.