LINGO-1 antibody ameliorates myelin impairment and spatial memory deficits in the early stage of 5XFAD mice.

AIMS: Multiple evidence has indicated that myelin injury is common in Alzheimer's disease (AD). However, whether myelin injury is an early event in AD and the relationship between it and cognitive function is still elusive. METHODS: Spatial memory of 5XFAD mice was determined by Morris water maze at 1 and 3 months old. Meanwhile, the deposition of Aß, the expression of myelin basic protein (MBP), LINGO-1, NgR, and myelin ultrastructure in many memory-associated brain regions were detected in one-month-old and three-month-old mice (before and after LINGO-1 antibody administration) using immunostaining, Western blot (WB), and transmission electron microscopy (TEM), respectively. RESULTS: No abnormal Aß deposition was found in one-month-old 5XFAD mice. However, spatial memory deficits were proved in accordance with an obvious demyelination in memory-associated brain regions in one-month-old mice and both deteriorated with age. Administration of LINGO-1 antibody could obviously restore the myelin impairments in CA1 and DG region and partially ameliorate spatial memory deficits. CONCLUSIONS: Our results demonstrated that myelin injury was an early event in 5XFAD mice even prior to emergence of deposition of Aß. Intervention with the LINGO-1 antibody could attenuate impaired spatial memory deficits by remyelination, which suggested that myelin injury was involved in spatial memory deficits and remyelination may be a potential therapeutic strategy in early stage of AD or mild cognitive impairments.

Spatial learning and memory impairments are associated with increased neuronal activity in 5XFAD mouse as measured by manganese-enhanced magnetic resonance imaging.

Dysfunction of neuronal activity is a major and early contributor to cognitive impairment in Alzheimer's disease (AD). To investigate neuronal activity alterations at early stage of AD, we encompassed behavioral testing and in vivo manganese-enhanced magnetic resonance imaging (MEMRI) in 5XFAD mice at early ages (1-, 2-, 3- and 5-month). The 5XFAD model over-express human amyloid precursor protein (APP) and presenilin 1 (PS1) harboring five familial AD mutations, which have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-ß. In the Morris water maze, 5XFAD mice showed longer escape latency and poorer memory retention. In the MEMRI, 5XFAD mice showed increased signal intensity in the brain regions involved in spatial cognition, including the entorhinal cortex, the hippocampus, the retrosplenial cortex and the caudate putamen. Of note, the observed alterations in spatial cognition were associated with increased MEMRI signal intensity. These findings indicate that aberrant increased basal neuronal activity may contribute to the spatial cognitive function impairment at early stage of AD, and may further suggest the potential use of MEMRI to predict cognitive impairments. Early intervention that targets aberrant neuronal activity may be crucial to prevent cognitive impairment.