Disruption of zinc transporter ZnT3 transcriptional activity and synaptic vesicular zinc in the brain of Huntington’s disease transgenic mouse

Abstract Background Huntington’s disease (HD) is a neurodegenerative disease that involves a complex combination of psychiatric, cognitive and motor impairments. Synaptic dysfunction has been implicated in HD pathogenesis. However, the mechanisms have not been clearly delineated. Synaptic vesicular zinc is closely linked to modulating synaptic transmission and maintaining cognitive ability. It is significant to assess zinc homeostasis for further revealing the pathogenesis of synaptic dysfunction and cognitive impairment in HD. Results Histochemical staining by autometallography indicated that synaptic vesicular zinc was decreased in the hippocampus, cortex and striatum of N171-82Q HD transgenic mice. Analyses by immunohistochemistry, Western blot and RT-PCR found that the expression of zinc transporter 3 (ZnT3) required for transport of zinc into synaptic vesicles was obviously reduced in these three brain regions of the HD mice aged from 14 to 20 weeks and BHK cells expressing mutant huntingtin. Significantly, dual-luciferase reporter gene and chromatin immunoprecipitation assays demonstrated that transcription factor Sp1 could activate ZnT3 transcription via its binding to the GC boxes in ZnT3 promoter. Moreover, mutant huntingtin was found to inhibit the binding of Sp1 to the promoter of ZnT3 and down-regulate ZnT3 expression, and the decline in ZnT3 expression could be ameliorated through overexpression of Sp1. Conclusions This is first study to reveal a significant loss of synaptic vesicular zinc and a decline in ZnT3 transcriptional activity in the HD transgenic mice. Our work sheds a novel mechanistic insight into pathogenesis of HD that mutant huntingtin down-regulates expression of ZnT3 through inhibiting binding of Sp1 to the promoter of ZnT3 gene, causing disruption of synaptic vesicular zinc homeostasis. Disrupted vesicular zinc ultimately leads to early synaptic dysfunction and cognitive deficits in HD. It is also suggested that maintaining normal synaptic vesicular zinc concentration is a potential therapeutic strategy for HD.

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Nuclear-targeting of mutant huntingtin fragments produces Huntington's disease-like phenotypes in transgenic mice

Human Molecular Genetics ◽

10.1093/hmg/ddh175 ◽

2004 ◽

Vol 13 (15) ◽

pp. 1599-1610 ◽

Cited By ~ 69

Author(s):

Gabriele Schilling ◽

Alena V. Savonenko ◽

Alexandra Klevytska ◽

Johanna L. Morton ◽

Stina M. Tucker ◽

...

Keyword(s):

Transgenic Mice ◽

Huntington's Disease ◽

Huntington’S Disease ◽

Mutant Huntingtin ◽

Nuclear Targeting

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The HDAC inhibitor 4b ameliorates the disease phenotype and transcriptional abnormalities in Huntington's disease transgenic mice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0804249105 ◽

2008 ◽

Vol 105 (40) ◽

pp. 15564-15569 ◽

Cited By ~ 205

Author(s):

Elizabeth A. Thomas ◽

Giovanni Coppola ◽

Paula A. Desplats ◽

Bin Tang ◽

Elisabetta Soragni ◽

...

Keyword(s):

Gene Expression ◽

Transgenic Mice ◽

Huntington's Disease ◽

Huntington’S Disease ◽

Hdac Inhibitor ◽

Brain Size ◽

Hdac Inhibitors ◽

Motor Deficits ◽

Therapeutic Effects ◽

Mutant Huntingtin

Transcriptional dysregulation has emerged as a core pathologic feature of Huntington's disease (HD), one of several triplet-repeat disorders characterized by movement deficits and cognitive dysfunction. Although the mechanisms contributing to the gene expression deficits remain unknown, therapeutic strategies have aimed to improve transcriptional output via modulation of chromatin structure. Recent studies have demonstrated therapeutic effects of commercially available histone deacetylase (HDAC) inhibitors in several HD models; however, the therapeutic value of these compounds is limited by their toxic effects. Here, beneficial effects of a novel pimelic diphenylamide HDAC inhibitor, HDACi 4b, in an HD mouse model are reported. Chronic oral administration of HDACi 4b, beginning after the onset of motor deficits, significantly improved motor performance, overall appearance, and body weight of symptomatic R6/2300Q transgenic mice. These effects were associated with significant attenuation of gross brain-size decline and striatal atrophy. Microarray studies revealed that HDACi 4b treatment ameliorated, in part, alterations in gene expression caused by the presence of mutant huntingtin protein in the striatum, cortex, and cerebellum of R6/2300Q transgenic mice. For selected genes, HDACi 4b treatment reversed histone H3 hypoacetylation observed in the presence of mutant huntingtin, in association with correction of mRNA expression levels. These findings suggest that HDACi 4b, and possibly related HDAC inhibitors, may offer clinical benefit for HD patients and provide a novel set of potential biomarkers for clinical assessment.

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Faculty Opinions recommendation of The HDAC inhibitor 4b ameliorates the disease phenotype and transcriptional abnormalities in Huntington's disease transgenic mice.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1124314.581471 ◽

2008 ◽

Author(s):

Karoly Mirnics

Keyword(s):

Transgenic Mice ◽

Huntington's Disease ◽

Huntington’S Disease ◽

Hdac Inhibitor ◽

Disease Phenotype

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Faculty Opinions recommendation of TR-FRET-based duplex immunoassay reveals an inverse correlation of soluble and aggregated mutant huntingtin in huntington's disease.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717951315.793456621 ◽

2012 ◽

Author(s):

Roger Barker ◽

Wei-Li Kuan

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Inverse Correlation ◽

Mutant Huntingtin

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Faculty Opinions recommendation of Mutant huntingtin fragmentation in immune cells tracks Huntington's disease progression.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717960625.793464988 ◽

2012 ◽

Author(s):

Stefano Di Donato

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Disease Progression ◽

Immune Cells ◽

Mutant Huntingtin

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Identification of Full-Length Wild-Type and Mutant Huntingtin Interacting Proteins by Crosslinking Immunoprecipitation in Mice Brain Cortex

Journal of Huntington s Disease ◽

10.3233/jhd-210476 ◽

2021 ◽

pp. 1-13

Author(s):

Karen A. Sap ◽

Arzu Tugce Guler ◽

Aleksandra Bury ◽

Dick Dekkers ◽

Jeroen A.A. Demmers ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Brain Cortex ◽

Full Length ◽

Biological Processes ◽

Interacting Proteins ◽

Mutant Huntingtin ◽

Wild Type ◽

Mutant Huntingtin Protein ◽

Mice Brain

Background: Huntington’s disease is a neurodegenerative disorder caused by a CAG expansion in the huntingtin gene, resulting in a polyglutamine expansion in the ubiquitously expressed mutant huntingtin protein. Objective: Here we set out to identify proteins interacting with the full-length wild-type and mutant huntingtin protein in the mice cortex brain region to understand affected biological processes in Huntington’s disease pathology. Methods: Full-length huntingtin with 20 and 140 polyQ repeats were formaldehyde-crosslinked and isolated via their N-terminal Flag-tag from 2-month-old mice brain cortex. Interacting proteins were identified and quantified by label-free liquid chromatography-mass spectrometry (LC-MS/MS). Results: We identified 30 interactors specific for wild-type huntingtin, 14 interactors specific for mutant huntingtin and 14 shared interactors that interacted with both wild-type and mutant huntingtin, including known interactors such as F8a1/Hap40. Syt1, Ykt6, and Snap47, involved in vesicle transport and exocytosis, were among the proteins that interacted specifically with wild-type huntingtin. Various other proteins involved in energy metabolism and mitochondria were also found to associate predominantly with wild-type huntingtin, whereas mutant huntingtin interacted with proteins involved in translation including Mapk3, Eif3h and Eef1a2. Conclusion: Here we identified both shared and specific interactors of wild-type and mutant huntingtin, which are involved in different biological processes including exocytosis, vesicle transport, translation and metabolism. These findings contribute to the understanding of the roles that wild-type and mutant huntingtin play in a variety of cellular processes both in healthy conditions and Huntington’s disease pathology.

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