(-)-Epigallocatechin-3-gallate ameliorates learning and memory deficits by adjusting the balance of TrkA/p75NTR signaling in APP/PS1 transgenic mice

Mol Neurobiol. 2014 Jun;49(3):1350-63. doi: 10.1007/s12035-013-8608-2. Epub 2013 Dec 20.

Abstract

Alzheimer's disease (AD) is pathologically characterized by deposition of β-amyloid (Aβ) peptides, which closely correlates with the balance of nerve growth factor (NGF)-related TrkA/p75NTR signaling. (-)-Epigallocatechin-3-gallate (EGCG) is used for prevention and treatment of many neurodegenerative diseases, including AD. However, whether the neuroprotective effects of EGCG treatment were via modulating the balance of TrkA/p75NTR signaling was still unknown. In this study, we found that EGCG treatment (2 mg·kg(-1)·day(-1)) dramatically ameliorated the cognitive impairments, reduced the overexpressions of Aβ(1-40) and amyloid precursor protein (APP), and inhibited the neuronal apoptosis in the APP/PS1 mice. Interestingly, the EGCG treatment enhanced the relative expression level of NGF by increasing the NGF/proNGF ratio in the APP/PS1 mice. Moreover, after EGCG treatment, TrkA signaling was activated by increasing the phosphorylation of TrkA following the increased phosphorylation of c-Raf, ERK1/2, and cAMP response element-binding protein (CREB), simultaneously the p75NTR signaling was significantly inhibited by decreasing the p75ICD expression, JNK2 phosphorylation, and cleaved-caspase 3 expression, so that the Aβ deposits and neuronal apoptosis in the hippocampus were inhibited.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Protein Precursor* / genetics
  • Animals
  • Avoidance Learning / drug effects
  • Avoidance Learning / physiology*
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Catechin / therapeutic use
  • Male
  • Memory Disorders / drug therapy
  • Memory Disorders / genetics
  • Memory Disorders / metabolism*
  • Mice
  • Mice, Transgenic
  • Presenilin-1* / genetics
  • Receptor, trkA / metabolism*
  • Receptors, Nerve Growth Factor / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology

Substances

  • Amyloid beta-Protein Precursor
  • Presenilin-1
  • Receptors, Nerve Growth Factor
  • Ngfr protein, mouse
  • Catechin
  • epigallocatechin gallate
  • Receptor, trkA