Gene expression analysis of frontotemporal lobar degeneration of the motor neuron disease type with ubiquitinated inclusions

Acta Neuropathol. 2007 Jul;114(1):81-94. doi: 10.1007/s00401-007-0240-7. Epub 2007 Jun 14.

Abstract

Neurodegenerative disorders share a process of aggregation of insoluble protein. Frontotemporal lobar degeneration with ubiquitinated inclusions (FTLD-U) is characterized by the presence of ubiquitin and TDP-43 positive aggregates which are likely related to specific gene expression profiles. We carried out gene expression microarray analysis on post-mortem brain tissue from FTLD-U, FTLD-MND, and controls. Using total RNA from carefully dissected frontal cortical layer II, we obtained gene expression profiles showing that FTLD-U and controls differ in over 100 networks, including those involved in synapse formation, the ubiquitin-proteasome system, endosomal sorting, and apoptosis. We performed qRT-PCR validation for three genes, representative of three different networks. Dynein axonemal light intermediate chain 1 (DNALI1) (microtubule/cytoskeleton network associated) expression was 3-fold higher and myeloid differentiation primary response gene 88 (MYD88) (signal transduction network) was 3.3 times higher in FTLD-U than FTLD-MND and controls; annexin A2 (ANXA2) (endosomal sorting) expression was 11.3-fold higher in FTLD-U than FTLD-MND and 2.3-fold higher than controls. The identification of progranulin (PGRN) gene mutations and TDP-43 as the major protein component of the ubiquitinated inclusions, are two recent landmark discoveries in the field of FTLD-U. We found 1.5-fold increase in TDP-43 in both FTLD-MND and FTLD-U while progranulin showed no gene expression differences between controls and FTLD-MND. However, one of the FTLD-U cases tested by Affymetrix microarray showed "absence call" of this transcript, suggesting absent or decreased gene expression. Our findings point to specific gene-linked-pathways which may be influenced by neurodegenerative disease process and may be targeted for further exploration.

Publication types

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

MeSH terms

  • Aged
  • Annexin A2 / genetics
  • Annexin A2 / metabolism
  • Axonemal Dyneins
  • Case-Control Studies
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Dementia / metabolism*
  • Dementia / pathology
  • Dyneins / genetics
  • Dyneins / metabolism
  • Female
  • Gene Expression Profiling*
  • Gene Expression Regulation
  • Humans
  • Inclusion Bodies / metabolism*
  • Inclusion Bodies / pathology
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Male
  • Middle Aged
  • Motor Neuron Disease / metabolism*
  • Motor Neuron Disease / pathology
  • Myeloid Differentiation Factor 88 / genetics
  • Myeloid Differentiation Factor 88 / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Progranulins
  • Ubiquitin / genetics
  • Ubiquitin / metabolism*

Substances

  • Annexin A2
  • DNA-Binding Proteins
  • GRN protein, human
  • Intercellular Signaling Peptides and Proteins
  • MYD88 protein, human
  • Myeloid Differentiation Factor 88
  • Progranulins
  • Ubiquitin
  • Axonemal Dyneins
  • DNAH9 protein, human
  • Dyneins