Abstract
AbstractBackgroundAPOE4 has been hypothesized to increase Alzheimer’s disease risk by increasing neuroinflammation, though the specific neuroinflammatory pathways involved are unclear.ObjectivesTo characterize CSF proteomic changes as a function of APOE4 copy number.MethodsWe analyzed targeted proteomic data obtained on ADNI CSF samples using a linear regression model adjusting for age, sex, and APOE4 copy number, and a second linear model also adjusting for AD clinical status. False Discovery Rate (FDR) was used to correct for multiple comparisons.ResultsIn the first model, increasing APOE4 copy number was associated with significant expression decreases in a CRP peptide (q=0.006), and significant expression increases in peptides from ALDOA, CH3L1 (YKL-40), and FABPH (q<0.05 for each). In the second model (controlling for age, sex, and AD clinical status), increasing APOE4 copy number was associated with significant expression decreases in a CRP peptide (q=0.009). In both models, increased APOE4 copy number was associated with trends towards lower expression of all 24 peptides from all 8 different complement proteins measured here, although none of these differences were statistically significant. The odds of this happening by chance for 24 unrelated peptides would be less than 1 in 16 million.ConclusionsIncreasing APOE4 copy number was associated with decreased CSF CRP levels and increased CSF ALDOA, CH3L1 and FABH levels; the CRP decrease remained significant after controlling for AD clinical status. Increased APOE4 copy number may also be associated with decreased CSF complement pathway protein levels, a hypothesis for investigation in future studies.
Publisher
Cold Spring Harbor Laboratory