Figure 5: Neuronal expression of ILEI is induced by TGF-β and reduced in AD brains.

(a) Double immunostaining for ILEI and cell type-specific markers in mouse brain sections. Neurofilament (NF), glial fibrillary acidic protein (GFAP) and Iba-I are marker proteins for neurons, astrocytes and microglia, respectively. Scale bars, 10 μm. (b) Effects of TGF-β treatment on cultured rat brain slices pretreated with non-targeting control or ILEI-specific siRNA. Forebrain slices containing the hippocampus and cerebral cortex were prepared from three Wistar rats (3-week-old, female). The relative levels of Aβ40 (n=3, mean±s.d.) and immunoblotting for ILEI are shown. Neuron-specific enolase (NSE) was used as a loading control. *P<0.05 versus vehicle or control, and NS, not significant by Student’s t-test. Aβ40 concentrations were as follows: control for TGF-β, 743.68±39.32; TGF-β, 631.23±54.36; control for ILEI-knockdown, 751.77±60.23; ILEI-knockdown, 901.28±12.61; ILEI-knockdown/TGF-β, 902.28±72.57 pmol per g protein (n=3, mean±s.d.). (c) Immunoblots for ILEI in Tris-buffered saline-extracted fractions from temporal cortices of AD patients (n=15, 82.0±4.5 years old, post-mortem interval 7.0±3.5 h), age-matched controls without neurological disease (n=15, 80.1±1.7 years old, post-mortem interval 8.0±5.4 h) and non-AD neurological disease controls (n=10, 79.6±3.7 years old, post-mortem interval 9.3±5.9 h). Non-AD disease controls were Parkinson’s disease (PD), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) or amyotrophic lateral sclerosis (ALS). The graph shows the relative intensity of ILEI normalized to NSE (mean±s.d.). **P<0.01 versus control or non-AD control and NS, not significant by Student’s t-test.