Probing the role of PPARγ in the regulation of late-onset Alzheimer's disease-associated genes

PLoS One. 2018 May 3;13(5):e0196943. doi: 10.1371/journal.pone.0196943. eCollection 2018.

Abstract

Peroxisome proliferator-activated receptor-γ (PPARγ), is a transcription factor that governs pathways, such as lipid metabolism and immune response, that have been implicated in the etiology of LOAD. Previously, we established HepG2-derived cell-lines with stable knockdown of PPARγ gene, and showed an increase in mRNA levels of genes mapped in the APOE linkage disequilibrium (LD) region on chromosome 19q13.32, with the greatest effect observed for APOE-mRNA. Here, we extended the analysis using our PPARγ knockdown model system and investigated the broader effect on expression changes of genes implicated in LOAD via genome wide association studies (GWAS). We applied the nCounter gene expression assay (NanoString) using a panel of twenty-four LOAD-associated genes inferred by proximity to the top significantly associated SNPs. Two independent PPARγ knockdown cell-lines showed changes in mRNA levels of a total of seven genes compared to a control HepG2 cell-line; six of which, ABCA7, APOE, CASS4, CELF1, PTK2B, and ZCWPW1, were upregulated and one, DSG2, was downregulated upon PPARγ knockdown. Our results propose that PPARγ may act as a master regulator of the transcription of several genes involved in LOAD pathogenesis. Our study provided the premise for further analyses including a larger set of genes positioned within a wider range of linkage disequilibrium (LD) regions tagged by all LOAD significantly associated SNPs.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Age of Onset
  • Alzheimer Disease / genetics*
  • Alzheimer Disease / metabolism
  • Alzheimer Disease / physiopathology
  • Apolipoproteins E / genetics
  • Apolipoproteins E / metabolism
  • CELF1 Protein / genetics
  • CELF1 Protein / metabolism
  • Desmoglein 2 / genetics
  • Desmoglein 2 / metabolism
  • Focal Adhesion Kinase 2 / genetics
  • Focal Adhesion Kinase 2 / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation*
  • Gene Knockdown Techniques
  • Genetic Predisposition to Disease*
  • Genome-Wide Association Study
  • Hep G2 Cells
  • Humans
  • Linkage Disequilibrium
  • Models, Biological
  • PPAR gamma / antagonists & inhibitors
  • PPAR gamma / deficiency
  • PPAR gamma / genetics*
  • Polymorphism, Single Nucleotide
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Signal Transduction

Substances

  • ABCA7 protein, human
  • ATP-Binding Cassette Transporters
  • Adaptor Proteins, Signal Transducing
  • Apolipoproteins E
  • CASS4 protein, human
  • CELF1 Protein
  • CELF1 protein, human
  • DSG2 protein, human
  • Desmoglein 2
  • PPAR gamma
  • RNA, Small Interfering
  • Focal Adhesion Kinase 2
  • PTK2B protein, human