Intrahippocampal injection of Aβ1-42 inhibits neurogenesis and down-regulates IFN-γ and NF-κB expression in hippocampus of adult mouse brain

Amyloid. 2013 Mar;20(1):13-20. doi: 10.3109/13506129.2012.755122. Epub 2013 Jan 4.

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by accumulation of amyloid plaques and neurofibrillary tangles. Amyloid-β (Aβ) is widely recognized as a key factor in the pathogenesis of AD. Aβ1-42 a major component of amyloid plaques, has shown synaptotoxicity associated with impaired long-term potentiation and cognitive deficits. Alteration of neurogenesis in AD patients has been reported, while little is known about how Aβ1-42 affects hippocampal neurogenesis in the adult brain. In this study, we injected human Aβ1-42 peptide into hippocampal CA1 area of adult mouse brain bilaterally and evaluated histological change and neurogenesis in the hippocampus. Hematoxylin and eosin (HE) stain showed that Aβ1-42-injection resulted in an extensive neurodegeneration in the Aβ-accumulated area and CA3 in hippocampus. Immunostaining showed that intrahippocampal Aβ1-42-injection dramatically decreased the number of bromodeoxyuridine (BrdU)-positive cells in the dentate gyrus (DG) compared to the vehicle injection. Moreover, a significant decrease in the number of BrdU/double-cortin double-positive cells in Aβ1-42-injected hippocampus was observed, suggesting that Aβ1-42-injection inhibited progenitor cell proliferation and neurogenesis in subgranular zone of the DG in the adult brain. We also found that the Aβ1-42-mediated decline of neurogenesis was associated with decreased protein levels of cytokines interferon-γ (IFN-γ) and transcription factor nuclear factor-kappa B (NF-κB) in the hippocampus. These results suggest that Aβ1-42 inhibits hippocampal neurogenesis in the adult brain possibly through down-regulation of INF-γ and NF-κB signaling pathway. This study provides a new insight into Aβ1-42-mediated decrease in hippocampal neurogenesis in the adult central nervous system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology
  • Amyloid beta-Peptides / pharmacology*
  • Animals
  • Gene Expression / drug effects
  • Hippocampus / drug effects*
  • Hippocampus / pathology
  • Humans
  • Injections, Intraventricular
  • Interferon-gamma / antagonists & inhibitors*
  • Interferon-gamma / biosynthesis
  • Male
  • Mice
  • Mice, Inbred BALB C
  • NF-kappa B / antagonists & inhibitors*
  • NF-kappa B / biosynthesis
  • Neural Stem Cells / drug effects
  • Neural Stem Cells / metabolism
  • Neural Stem Cells / pathology
  • Neurogenesis / drug effects*
  • Peptide Fragments / pharmacology*

Substances

  • Amyloid beta-Peptides
  • NF-kappa B
  • Peptide Fragments
  • amyloid beta-protein (1-42)
  • Interferon-gamma