Adipose tissue dysfunction tracks disease progression in two Huntington's disease mouse models

Area of Science:

• Neuroscience
• Metabolic Disease Research
• Genetics

Background:

• Huntington's disease (HD) is characterized by neurological symptoms, but weight loss and metabolic dysfunction are also common, particularly in later stages.
• The underlying mechanisms driving weight loss in HD remain largely unknown.
• Adipose tissue dysfunction is increasingly recognized as a potential contributor to metabolic disturbances in neurodegenerative diseases.

Purpose of the Study:

• To investigate the role of adipose tissue dysfunction in the pathogenesis of Huntington's disease.
• To determine if mutant huntingtin directly affects adipocytes and their function.
• To explore potential biomarkers and therapeutic targets related to adipose tissue in HD.

Main Methods:

• Utilized two mouse models of Huntington's disease: R6/2 transgenic and CAG140 knock-in strains.
• Analyzed adipose tissue from HD mice at various disease stages to assess adipocyte phenotype and gene expression.
• Measured levels of adipose-derived hormones (leptin, adiponectin) in HD mouse models.
• Expressed inducible mutant huntingtin in an adipocyte cell line to study direct cellular effects.
• Investigated the impact of mutant huntingtin on PGC-1alpha transcriptional activity in adipocytes.

Main Results:

• Adipose tissue dysfunction, including adipocyte de-differentiation and impaired fat storage gene expression, was observed early in HD mouse models.
• Reduced levels of leptin and adiponectin were detected in HD mice, preceding significant weight loss and neurological symptoms.
• Expression of mutant huntingtin in adipocytes recapitulated impaired gene expression and lipid accumulation.
• Mutant huntingtin was found to inhibit the transcriptional activity of the PGC-1alpha co-activator in adipocytes.

Conclusions:

• Mutant huntingtin has direct detrimental effects on adipose tissue, independent of overt neurological symptoms.
• Adipose tissue dysfunction and associated hormonal changes are early events in Huntington's disease progression.
• Adipose-derived hormones may serve as accessible biomarkers for HD prognosis.
• Targeting adipose tissue presents a potential therapeutic strategy to improve the quality of life for individuals with Huntington's disease.