The gene expression profiles of induced pluripotent stem cells from individuals with childhood cerebral adrenoleukodystrophy are consistent with proposed mechanisms of pathogenesis
Open Access
- 4 October 2012
- journal article
- Published by Springer Science and Business Media LLC in Stem Cell Research & Therapy
- Vol. 3 (5), 39
- https://doi.org/10.1186/scrt130
Abstract
X-linked adrenoleukodystrophy (X-ALD) is a complex disorder with variable expressivity that affects the nervous, adrenocortical and male reproductive systems. Although ABCD1 mutations are known to provide the genetic basis for X-ALD, its pathogenesis is not fully elucidated. While elevated very long chain fatty acid (VLCFA) levels in blood and reduced VLCFA catabolic activity in cultured fibroblasts are biomarkers used to identify ABCD1 mutation carriers, the roles peroxisomal lipid metabolism play in disease etiology are unknown. Primary skin fibroblasts from two male patients with the childhood cerebral form of the disease (CCALD) caused by ABCD1 frameshift or missense mutations and three healthy donors were transduced with retroviral vectors expressing the OCT4, SOX2, KLF4 and c-MYC factors. Candidate induced pluripotent stem cells (iPSCs) were subject to global gene expression, DNA methylation, DNA copy number variation, and genotyping analysis and tested for pluripotency through in vitro differentiation and teratoma formation. Saturated VLCFA (sVLCFA) and plasmalogen levels in primary fibroblasts and iPSCs from healthy donors as well as CCALD patients were determined through mass spectroscopy. Skin fibroblasts from CCALD patients and healthy donors were reprogrammed into validated iPSCs. Unlike fibroblasts, CCALD patient iPSCs show differentially expressed genes (DEGs) relevant to both peroxisome abundance and neuroinflammation. Also, in contrast to fibroblasts, iPSCs from patients showed no significant difference in sVLCFA levels relative to those from controls. In all cell types, the plasmalogen levels tested did not correlate with ABCD1 mutation status. Normal ABCD1 gene function is not required for reprogramming skin fibroblasts into iPSCs or maintaining pluripotency. Relative to DEGs found in fibroblasts, DEGs uncovered in comparisons of CCALD patient and control iPSCs are more consistent with major hypotheses regarding disease pathogenesis. These DEGs were independent of differences in sVLCFA levels, which did not vary according to ABCD1 mutation status. The highlighted genes provide new leads for pathogenic mechanisms that can be explored in animal models and human tissue specimens. We suggest that these iPSC resources will have applications that include assisting efforts to identify genetic and environmental modifiers and screening for therapeutic interventions tailored towards affected cell populations and patient genotypes.Keywords
This publication has 83 references indexed in Scilit:
- Somatic coding mutations in human induced pluripotent stem cellsNature, 2011
- Dynamic Changes in the Copy Number of Pluripotency and Cell Proliferation Genes in Human ESCs and iPSCs during Reprogramming and Time in CultureCell Stem Cell, 2011
- The role of ELOVL1 in very long‐chain fatty acid homeostasis and X‐linked adrenoleukodystrophyEMBO Molecular Medicine, 2010
- Identification and functional relevance of de novo DNA methylation in cancerous B‐cell populationsJournal of Cellular Biochemistry, 2010
- Identification of novel mutations and sequence variation in the Zellweger syndrome spectrum of peroxisome biogenesis disordersHuman Mutation, 2009
- Systematic and integrative analysis of large gene lists using DAVID bioinformatics resourcesNature Protocols, 2008
- Generation of human induced pluripotent stem cells from dermal fibroblastsProceedings of the National Academy of Sciences of the United States of America, 2008
- DNA methylation profiles in diffuse large B-cell lymphoma and their relationship to gene expression statusLeukemia, 2008
- Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined FactorsCell, 2007
- Roles of cPLA2α and arachidonic acid in cancerBiochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 2006