Adipose tissue dysfunction tracks disease progression in two Huntington's disease mouse models.
In addition to the hallmark neurological manifestations of Huntington's disease (HD), weight loss with metabolic dysfunction is often observed in the later stages of disease progression and is associated with poor prognosis. The mechanism for weight loss in HD is unknown. Using two mouse models of HD, the R6/2 transgenic and CAG140 knock-in mouse strains, we demonstrate that adipose tissue dysfunction is detectable at early ages and becomes more pronounced as the disease progresses. Adipocytes acquire a 'de-differentiated' phenotype characterized by impaired expression of fat storage genes. In addition, HD mice exhibit reduced levels of leptin and adiponectin, adipose tissue-derived hormones that regulate food intake and glucose metabolism. Importantly, some of these changes occur prior to weight loss and development of some of the characteristic neurological symptoms. We demonstrate that impaired gene expression and lipid accumulation in adipocytes can be recapitulated by expression of an inducible mutant huntingtin transgene in an adipocyte cell line and that mutant huntingtin inhibits transcriptional activity of the PGC-1alpha co-activator in adipocytes, which may contribute to aberrant gene expression. Thus, our findings indicate that mutant huntingtin has direct detrimental effects in cell types other than neurons. The results also indicate that circulating adipose-tissue-derived hormones may be accessible markers for HD prognosis and progression and suggest that adipose tissue may be a useful therapeutic target to improve standard of life for HD patients.
Phan
Jack
J
Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095, USA.
Hickey
Miriam A
MA
Zhang
Peixiang
P
Chesselet
Marie-Francoise
MF
Reue
Karen
K
D017667:Adipocytes / Q000378:metabolism / Q000473:pathology; D054392:Adipokines / Q000378:metabolism; D000273:Adipose Tissue / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D005786:Gene Expression Regulation; D055879:Gene Knock-In Techniques; D006801:Humans; D006816:Huntington Disease / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D009929:Organ Size; D009928:Organ Specificity; D047495:PPAR gamma / Q000235:genetics; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D020218:Response Elements / Q000235:genetics; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors
D054392:Adipokines; D047495:PPAR gamma; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D050486:Serotonin Plasma Membrane Transport Proteins; C493231:Slc6a4 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors