Decreased expression of hypothalamic neuropeptides in Huntington disease transgenic mice with expanded polyglutamine-EGFP fluorescent aggregates.
Huntington disease is caused by polyglutamine (polyQ) expansion in huntingtin. Selective and progressive neuronal loss is observed in the striatum and cerebral cortex in Huntington disease. We have addressed whether expanded polyQ aggregates appear in regions of the brain apart from the striatum and cortex and whether there is a correlation between expanded polyQ aggregate formation and dysregulated transcription. We generated transgenic mouse lines expressing mutant truncated N-terminal huntingtin (expanded polyQ) fused with enhanced green fluorescent protein (EGFP) and carried out a high-density oligonucleotide array analysis using mRNA extracted from the cerebrum, followed by TaqMan RT-PCR and in situ hybridization. The transgenic mice formed expanded polyQ-EGFP fluorescent aggregates and this system allowed us to directly visualize expanded polyQ aggregates in various regions of the brain without performing immunohistochemical studies. We show here that polyQ-EGFP aggregates were intense in the hypothalamus, where the expression of six hypothalamic neuropeptide mRNAs, such as oxytocin, vasopressin and cocaine-amphetamine-regulated transcript, was down-regulated in the transgenic mouse brain without observing a significant loss of hypothalamic neurons. These results indicate that the hypothalamus is susceptible to aggregate formation in these mice and this may result in the down-regulation of specific genes in this region of the brain.
Kotliarova
Svetlana
S
Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan.
Jana
Nihar R
NR
Sakamoto
Naoaki
N
Kurosawa
Masaru
M
Miyazaki
Haruko
H
Nekooki
Munenori
M
Doi
Hiroshi
H
Machida
Yoko
Y
Wong
Hon Kit
HK
Suzuki
Taishi
T
Uchikawa
Chiharu
C
Kotliarov
Yuri
Y
Uchida
Kazuyo
K
Nagao
Yoshiro
Y
Nagaoka
Utako
U
Tamaoka
Akira
A
Oyanagi
Kiyomitsu
K
Oyama
Fumitaka
F
Nukina
Nobuyuki
N
D000818:Animals; D001923:Brain Chemistry / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics / Q000378:metabolism*; D007031:Hypothalamus / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D009479:Neuropeptides / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D010121:Oxytocin / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D014667:Vasopressins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics
C086055:HTT protein, human; C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D009687:Nuclear Proteins; D010455:Peptides; D012333:RNA, Messenger; C485184:enhanced green fluorescent protein; D014667:Vasopressins; D049452:Green Fluorescent Proteins; C097188:polyglutamine; D010121:Oxytocin