Quantitative Proteomic Analysis of Mitochondria in Aging PS-1 Transgenic Mice

Abstract

Accumulating evidence suggests mitochondrial alterations are intimately associated with the pathogenesis of Alzheimer's disease (AD). To determine if mutations of presenilin-1 (PS-1) affect levels of mitochondrial proteins at different ages we enriched mitochondrial fractions from 3, 6, 12 month old knock-in mice expressing the M146V PS-1 mutation and identified, and quantified proteins using cleavable Isotope Coded Affinity Tag (ICAT) labeling and two dimensional liquid chromatography/tandem mass spectrometry (2D-LC/MS/MS). Using this approach, 165 nonredundant proteins were identified with 80 of them present in all three age groups. Specifically, at young ages (3 and 6 months), Na + /K + ATPase and several signal transduction proteins exhibited elevated levels, but dropped dramatically at 12 months. In contrast, components of the oxidative phosporylation pathway (OXPHOS), the mitochondrial permeability transition pore (MPTP), and energy metabolism proteins remained unchanged at 3 months but significantly increased with age. We propose that alterations in calcium homeostasis induced by the PS-1 mutation have a major impact in young animals by inhibiting function of relevant proteins and inducing compensatory changes. However, in older mice combination of the PS-1 mutation and accumulated oxidative damage results in functional suppression of OXPHOS and MPTP proteins requiring a compensatory increase in expression levels. In contrast, signal transduction proteins showed decreased levels due to a break down in the compensatory mechanisms. The dysfunction of Na + /K + ATPase and signal transduction proteins may induce impaired cognition and memory before neurodegeneration occurs.

Mitochondrial DNA deletions and differential mitochondrial DNA content in Rhesus monkeys: Implications for aging

“…This phenomenon – that is, the accumulation of defective mitochondria and a corresponding decrease in mitochondrial function with the increase of age – has been observed: 1) in postmortem brains from patients with AD [36] and in transgenic mice with over-expressed amyloid precursor protein [42], and 3) in a presenilin 1 transgenic mouse model [43]. Briefly, Hirai et al [41] found an increase in damaged mitochondria and defective mtDNA, including increased mtDNA deletions in hippocampal and cortical neurons, from postmortem brains from AD patients, compared to the mtDNA in postmortem hippocampal and cortical neurons from healthy control subjects, indicating that mitochondrial abnormalities are evident in AD brains [36].…”

Targeting Mitochondrial Metal Dyshomeostasis for the Treatment of Neurodegeneration

“…Human AD brain displays evidence of decreased mitochondrial number and mitochondrial damage [147,148], decreased complex IV activity [149][150][151] and deletions in mitochondrial DNA correlate with impaired complex IV activity in human AD brain [152]. Transgenic mice modeling AD exhibit impaired mitochondrial function and reactive oxygen species (ROS)-related mitochondrial damage [147,153,154]. Indeed mitochondrial dysfunction is an early feature in transgenic AD mice (reviewed in [155]), as evidenced for example by impaired Ca 2+ uptake [156] and decreased complex IV activity [157] from 2 months of age.…”

Neuroproteomics — LC-MS Quantitative Approaches

“…This isotope-labeling technology has been applied in several neuroscience projects such as the study of the influence of aging in the proteome of CSF (cerebrospinal fluid) [72], the study of differential mitochondrial proteins analysis in the pathophysiology of Parkinson's [73] or Alzheimer's diseases [74], and also to aid the study of the expression of synaptosomal protein in cerebral ischemia [75], migraine mouse models [76], or in the study of addiction [77].…”