Reduced retinal function in amyloid precursor protein-over-expressing transgenic mice via attenuating glutamate-N-methyl-d-aspartate receptor signaling

J Neurochem. 2008 Oct;107(1):279-90. doi: 10.1111/j.1471-4159.2008.05606.x. Epub 2008 Aug 7.

Abstract

Here, we examined whether amyloid-beta (Abeta) protein participates in cell death and retinal function using three types of transgenic (Tg) mice in vivo [human mutant amyloid precursor protein (APP) Tg (Tg 2576) mice, mutant presenilin-1 (PS-1) knock-in mice, and APP/PS-1 double Tg mice]. ELISA revealed that the insoluble form of Abeta(1-40) was markedly accumulated in the retinas of APP and APP/PS-1, but not PS-1 Tg, mice (vs. wild-type mice). In APP Tg and APP/PS-1 Tg mice, immunostaining revealed accumulations of intracellular Abeta(1-42) in retinal ganglion cells and in the inner and outer nuclear layers. APP Tg and APP/PS-1 Tg, but not PS-1 Tg, mice had less NMDA-induced retinal damage than wild-type mice, and the reduced damage in APP/PS-1 Tg mice was diminished by the pre-treatment of N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, a gamma-secretase inhibitor. Furthermore, the number of TUNEL-positive cells was significantly less in ganglion cell layer of APP/PS-1 Tg mice than PS-1 Tg mice 24 h after NMDA injection. The phosphorylated form of calcium/calmodulin-dependent protein kinase IIalpha (CaMKIIalpha), but not total CaMKIIalpha or total NMDA receptor 1 (NR1) subunit, in total retinal extracts was decreased in non-treated retinas of APP/PS-1 Tg mice (vs. wild-type mice). CaMKIIalpha and NR2B proteins, but not NR1, in retinal membrane fraction were significantly decreased in APP/PS-1 Tg mice as compared with wild-type mice. The NMDA-induced increase in p-CaMKIIalpha in the retina was also lower in APP/PS-1 Tg mice than in wild-type mice. In electroretinogram and visual-evoked potential recordings, the implicit time to each peak from a light stimulus was prolonged in APP/PS-1 mice versus wild-type mice. Hence, Abeta may impair retinal function by reducing activation of NMDA-receptor signaling pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid Precursor Protein Secretases / antagonists & inhibitors
  • Amyloid Precursor Protein Secretases / metabolism
  • Amyloid beta-Peptides / metabolism*
  • Amyloid beta-Protein Precursor / genetics
  • Amyloid beta-Protein Precursor / metabolism*
  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
  • Down-Regulation / drug effects
  • Down-Regulation / physiology
  • Enzyme Inhibitors / pharmacology
  • Evoked Potentials, Visual / drug effects
  • Evoked Potentials, Visual / genetics
  • Glutamic Acid / metabolism*
  • Humans
  • Mice
  • Mice, Transgenic
  • Nerve Degeneration / genetics
  • Nerve Degeneration / metabolism
  • Nerve Degeneration / physiopathology
  • Peptide Fragments / metabolism
  • Presenilin-1 / genetics
  • Presenilin-1 / metabolism
  • Receptors, N-Methyl-D-Aspartate / agonists
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Retinal Diseases / genetics
  • Retinal Diseases / metabolism*
  • Retinal Diseases / physiopathology
  • Retinal Ganglion Cells / metabolism*
  • Retinal Ganglion Cells / pathology
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Vision, Ocular / drug effects
  • Vision, Ocular / genetics

Substances

  • Amyloid beta-Peptides
  • Amyloid beta-Protein Precursor
  • Enzyme Inhibitors
  • NR2B NMDA receptor
  • Peptide Fragments
  • Presenilin-1
  • Receptors, N-Methyl-D-Aspartate
  • amyloid beta-protein (1-40)
  • amyloid beta-protein (1-42)
  • Glutamic Acid
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • Amyloid Precursor Protein Secretases