Neuron type-specific increase in lamin B1 contributes to nuclear dysfunction in Huntington's disease

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Lamins are essential nuclear proteins regulating nuclear structure and function.
• Huntington's disease (HD) is a neurodegenerative disorder caused by CAG repeat expansions, leading to mutant huntingtin protein aggregation.
• Altered nuclear function and transport are implicated in HD pathogenesis.

Purpose of the Study:

• To investigate the role of lamin B1 in the pathophysiology of Huntington's disease.
• To explore lamin B1 as a potential therapeutic target for HD.

Main Methods:

• Fluorescence-activated nuclear suspension imaging to quantify lamin B1 levels in neuronal nuclei.
• ChIP-sequencing to analyze lamin-associated chromatin domains and chromatin accessibility.
• Pharmacological intervention with betulinic acid in a mouse model of HD.

Main Results:

• Increased lamin B1 levels were observed in neurons of HD models, correlating with nuclear morphology changes and disrupted nucleocytoplasmic transport.
• ChIP-sequencing revealed altered lamin-associated chromatin domains, changes in chromatin accessibility, and transcriptional dysregulation in HD hippocampi.
• Betulinic acid treatment normalized lamin B1 levels, restored nuclear homeostasis, and ameliorated motor and cognitive deficits in R6/1 HD mice.

Conclusions:

• Elevated lamin B1 is a novel pathogenic mechanism in Huntington's disease.
• Targeting lamin B1 offers a promising therapeutic strategy for HD intervention.
• Restoring nuclear homeostasis via lamin B1 modulation can alleviate HD-related neurological dysfunction.