Fig. 3

Increased GPNMB protein levels and cerebral expression pattern in 5XFAD mice. (a) Abundant GPNMB staining was detected throughout the whole brain in 12-month-old 5XFAD mice, e.g. in the subiculum. (b) High-power view of GPNMB-positive cells surrounding an amyloid plaque core. (c) Quantitative analysis of GPNMB protein levels in TBS- and SDS-soluble brain fractions of 12-month-old WT, 5XFAD and APP23 mice revealed a highly significant increase in GPNMB levels in 5XFAD mice compared to WT animals, while no elevated levels could be observed in APP23 mice. (d) GPNMB immunoreactivity was also demonstrated in the spinal cord (SC) of 12-month-old 5XFAD mice. GPNMB was abundantly expressed throughout the whole SC tissue and showed co-localization with IBA1-positive microglia cells (parallel sections). (e) As demonstrated by RT-PCR analyses, 5XFAD mice showed a highly significant increase in GPNMB mRNA levels in the SC when compared to WT controls. However, no such differences were observed in peripheral liver samples serving as a non-neuronal control tissue. Enzyme-linked immunosorbent assay revealed highly increased GPNMB protein level in 5XFAD SC tissue compared to WT controls (f). All data are given as mean ± SD. ***P < 0.001. Scale bar: A = 133 μm, B = 25 μm; D = 200 μm (upper panel), 20 μm (lower panel)