The role of Twist1 in mutant huntingtin–induced transcriptional alterations and neurotoxicity

• Published in: The Journal of biological chemistry Vol. 293; no. 30; pp. 11850 - 11866
• Main Authors: Pan, Yanchun, Zhu, Ying, Yang, Wei, Tycksen, Eric, Liu, Shaopeng, Palucki, John, Zhu, Linjian, Sasaki, Yo, Sharma, Mukesh K., Kim, Albert H., Zhang, Bo, Yano, Hiroko
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 27-07-2018; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; brain-derived neurotrophic factor (BDNF); Brain-Derived Neurotrophic Factor - genetics; Brain-Derived Neurotrophic Factor - metabolism; Cells, Cultured; DNA Methylation; Epigenesis, Genetic; Female; gene expression; Gene Regulatory Networks; Humans; Huntingtin Protein - genetics; Huntingtin Protein - metabolism; Huntington disease; Huntington Disease - genetics; Huntington Disease - metabolism; Male; Mice; Molecular Bases of Disease; Mutation; neurodegeneration; neurodegenerative disease; Neurons - metabolism; primary neurons; RNA-Seq; transcription factor; Transcriptional Activation; transcriptional dysregulation; Twist-Related Protein 1 - genetics; Twist-Related Protein 1 - metabolism; Twist1; transcription factor; neurodegenerative disease; RNA-Seq; Huntington disease; brain-derived neurotrophic factor (BDNF); neurodegeneration; DNA methylation; primary neurons; transcriptional dysregulation; gene expression; Twist1
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA117.001211

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by an abnormal expansion of polyglutamine repeats in the huntingtin protein (Htt). Transcriptional dysregulation is an early event in the course of HD progression and is thought to contribute to disease pathogenesis, but how mutant Htt causes transcriptional alterations and subsequent cell death in neurons is not well understood. RNA-Seq analysis revealed that expression of a mutant Htt fragment in primary cortical neurons leads to robust gene expression changes before neuronal death. Basic helix-loop-helix transcription factor Twist1, which is essential for embryogenesis and is normally expressed at low levels in mature neurons, was substantially up-regulated in mutant Htt–expressing neurons in culture and in the brains of HD mouse models. Knockdown of Twist1 by RNAi in mutant Htt–expressing primary cortical neurons reversed the altered expression of a subset of genes involved in neuronal function and, importantly, abrogated neurotoxicity. Using brain-derived neurotrophic factor (Bdnf), which is known to be involved in HD pathogenesis, as a model gene, we found that Twist1 knockdown could reverse mutant Htt–induced DNA hypermethylation at the Bdnf regulatory region and reactivate Bdnf expression. Together, these results suggest that Twist1 is an important upstream mediator of mutant Htt–induced neuronal death and may in part operate through epigenetic mechanisms.