Age-dependent decrease in chaperone activity impairs MANF expression, leading to Purkinje cell degeneration in inducible SCA17 mice.
Although protein-misfolding-mediated neurodegenerative diseases have been linked to aging, how aging contributes to selective neurodegeneration remains unclear. We established spinocerebellar ataxia 17 (SCA17) knockin mice that inducibly express one copy of mutant TATA box binding protein (TBP) at different ages by tamoxifen-mediated Cre recombination. We find that more mutant TBP accumulates in older mouse and that this accumulation correlates with age-related decreases in Hsc70 and chaperone activity. Consistently, older SCA17 mice experienced earlier neurological symptom onset and more severe Purkinje cell degeneration. Mutant TBP shows decreased association with XBP1s, resulting in the reduced transcription of mesencephalic astrocyte-derived neurotrophic factor (MANF), which is enriched in Purkinje cells. Expression of Hsc70 improves the TBP-XBP1s interaction and MANF transcription, and overexpression of MANF ameliorates mutant TBP-mediated Purkinje cell degeneration via protein kinase C (PKC)-dependent signaling. These findings suggest that the age-related decline in chaperone activity affects polyglutamine protein function that is important for the viability of specific types of neurons.
Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA.
Su
S
Yang
Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
Shanshan
S
Huang
Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA.
Marta A
MA
Gaertig
Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China. Electronic address: xli2@emory.edu.
Xiao-Jiang
XJ
Li
Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Room 355, Atlanta, GA 30322, USA. Electronic address: sli@emory.edu.
Shihua
S
Li
D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D004195:Disease Models, Animal; D004965:Estrogen Antagonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000235:genetics*; D050883:HSC70 Heat-Shock Proteins / Q000378:metabolism; D047468:Immunoprecipitation; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D009410:Nerve Degeneration / Q000473:pathology*; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011689:Purkinje Cells / Q000473:pathology*; D000071701:Regulatory Factor X Transcription Factors; D035181:TATA-Box Binding Protein / Q000235:genetics*; D013629:Tamoxifen / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D000071717:X-Box Binding Protein 1
D004268:DNA-Binding Proteins; D004965:Estrogen Antagonists; D050883:HSC70 Heat-Shock Proteins; C534671:MANF protein, mouse; D009414:Nerve Growth Factors; D010455:Peptides; D000071701:Regulatory Factor X Transcription Factors; D035181:TATA-Box Binding Protein; C509817:TBP protein, human; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse; D013629:Tamoxifen; C097188:polyglutamine; D011493:Protein Kinase C