Huntington's disease of the endocrine pancreas: insulin deficiency and diabetes mellitus due to impaired insulin gene expression.
In a transgenic mouse model of the neurodegenerative disorder Huntington's disease (HD), age-dependent neurologic defects are accompanied by progressive alterations in glucose tolerance that culminate in the development of diabetes mellitus and insulin deficiency. Pancreatic islets from HD transgenic mice express reduced levels of the pancreatic islet hormones insulin, somatostatin, and glucagon and exhibit intrinsic defects in insulin production. Intranuclear inclusions accumulate with aging in transgenic pancreatic islets, concomitant with the decline in glucose tolerance. HD transgenic mice develop an age-dependent reduction of insulin mRNA expression and diminished expression of key regulators of insulin gene transcription, including the pancreatic homeoprotein PDX-1, E2A proteins, and the coactivators CBP and p300. Disrupted expression of a subset of transcription factors in pancreatic beta cells by a polyglutamine expansion tract in the huntingtin protein selectively impairs insulin gene expression to result in insulin deficiency and diabetes. Selective dysregulation of gene expression in triplet repeat disorders provides a mechanism for pleiotropic cellular dysfunction that restricts the toxicity of ubiquitously expressed proteins to highly specialized subpopulations of cells.
Andreassen
Ole A
OA
Neurochemistry Laboratory, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Dedeoglu
Alpaslan
A
Stanojevic
Violeta
V
Hughes
Duncan B
DB
Browne
Susan E
SE
Leech
Colin A
CA
Ferrante
Robert J
RJ
Habener
Joel F
JF
Beal
M Flint
MF
Thomas
Melissa K
MK
D000375:Aging; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D003920:Diabetes Mellitus / Q000209:etiology* / Q000378:metabolism; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation; D005934:Glucagon / Q000378:metabolism; D018149:Glucose Intolerance / Q000209:etiology; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000150:complications* / Q000378:metabolism; D007150:Immunohistochemistry; D007328:Insulin / Q000097:blood / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013004:Somatostatin / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D001786:Blood Glucose; C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D007328:Insulin; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D013004:Somatostatin; D005934:Glucagon; D002118:Calcium