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Yin J, Tuo CM, Yu KY, Hu XH, Fan YY, Wu MN. Diurnal Characteristics of the Orexin System Genes and Its Effects on Pathology at Early Stage in 3xTg-AD Mice. Neuromolecular Med 2023; 25:632-643. [PMID: 37843792 DOI: 10.1007/s12017-023-08767-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/06/2023] [Indexed: 10/17/2023]
Abstract
Orexin and its receptors are closely related to the pathogenesis of Alzheimer's disease (AD). Although the expression of orexin system genes under physiological condition has circadian rhythm, the diurnal characteristics of orexin system genes, and its potential role in the pathogenesis in AD are unknown. In the present study, we hope to elucidate the diurnal characteristics of orexin system genes at the early stage of AD, and to investigate its potential role in the development of AD neuropathology. We firstly detected the mRNA levels of orexin system genes, AD risk genes and core clock genes (CCGs) in hypothalamus and hippocampus in 6-month-old male 3xTg-AD mice and C57BL/6J (wild type, WT) control mice, then analyzed diurnal expression profiles of all genes using JTK_CYCLE algorithm, and did the correlation analysis between expression of orexin system genes and AD risk genes or CCGs. In addition, the expression of β-amyloid protein (Aβ) and phosphorylated tau (p-tau) protein were measured. The results showed that the diurnal mRNA expression profiles of PPO, OX1R, OX2R, Bace2, Bmal1, Per1, Per2 and Cry1 in the hypothalamus, and gene expression of OX1R, OX2R, Bace1, Bmal1, Per1 and Cry2 in the hippocampus in 3xTg-AD mice were different from that in WT mice. Furthermore, there is positive correlation between orexin system genes and AD risk genes or CCGs in the brain in 3xTg-AD mice. In addition, the expression of Aβ and p-tau in hippocampus in 3xTg-AD mice were significantly increased, and the expression of p-tau is higher in night than in day. These results indicate that the abnormal expression profiles of orexin system genes and its interaction with AD risk genes or CCGs might exert important role in the pathogenesis of AD, which will increase the expression of Aβ and p-tau, and accelerate the development of AD.
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Affiliation(s)
- Jing Yin
- Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology in Shanxi Province, Shanxi Medical University, Taiyuan, Shanxi, China
- Department of Pharmacology, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Chun-Mei Tuo
- Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology in Shanxi Province, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Kai-Yue Yu
- Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology in Shanxi Province, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Xiao-Hong Hu
- Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Taiyuan, Shanxi, China
- Key Laboratory of Cellular Physiology in Shanxi Province, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Yan-Ying Fan
- Department of Pharmacology, Shanxi Medical University, Taiyuan, Shanxi, China.
| | - Mei-Na Wu
- Department of Physiology, Shanxi Medical University, Taiyuan, Shanxi, China.
- Key Laboratory of Cellular Physiology, Ministry of Education, Taiyuan, Shanxi, China.
- Key Laboratory of Cellular Physiology in Shanxi Province, Shanxi Medical University, Taiyuan, Shanxi, China.
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Costello A, Linning-Duffy K, Vandenbrook C, Donohue K, O'Hara BF, Kim A, Lonstein JS, Yan L. Effects of light therapy on sleep/wakefulness, daily rhythms, and the central orexin system in a diurnal rodent model of seasonal affective disorder. J Affect Disord 2023; 332:299-308. [PMID: 37060954 PMCID: PMC10161688 DOI: 10.1016/j.jad.2023.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 03/31/2023] [Accepted: 04/07/2023] [Indexed: 04/17/2023]
Abstract
BACKGROUND Bright light therapy (BLT) is the first-line treatment for seasonal affective disorder. However, the neural mechanisms underlying BLT are unclear. To begin filling this gap, the present study examined the impact of BLT on sleep/wakefulness, daily rhythms, and the wakefulness-promoting orexin/hypocretin system in a diurnal rodent, Nile grass rats (Arvicanthis niloticus). METHODS Male and female grass rats were housed under a 12:12 h light/dark cycle with dim light (50 lx) during the day. The experimental group received daily 1-h early morning BLT (full-spectrum white light, 10,000 lx), while the control group received narrowband red light for 4 weeks. Sleep/wakefulness and in-cage locomotor activity were monitored, followed by examination of hypothalamic prepro-orexin and orexin receptors OX1R and OX2R expression in corticolimbic brain regions. RESULTS The BLT group had higher wakefulness during light treatment, better nighttime sleep quality, and improved daily rhythm entrainment compared to controls. The impact of BLT on the orexin system was sex- and brain region-specific, with males showing higher OX1R and OX2R in the CA1, while females showed higher prepro-orexin but lower OX1R and OX2R in the BLA, compared to same-sex controls. LIMITATIONS The present study focused on the orexin system in a limited number of brain regions at a single time point. Sex wasn't a statistical factor, as male and female cohorts were run independently. CONCLUSIONS The diurnal grass rats show similar behavioral responses to BLT as humans, thus could be a good model for further elucidating the neural mechanisms underlying the therapeutic effects of BLT.
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Affiliation(s)
- Allison Costello
- Department of Psychology, Michigan State University, United States of America.
| | | | | | - Kevin Donohue
- Department of Electrical and Computer Engineering, Michigan State University, United States of America
| | - Bruce F O'Hara
- Department of Biology, University of Kentucky, United States of America
| | - Antony Kim
- Department of Architecture, UC Berkeley, United States of America
| | - Joseph S Lonstein
- Department of Psychology, Michigan State University, United States of America; Neuroscience Program, Michigan State University, United States of America
| | - Lily Yan
- Department of Psychology, Michigan State University, United States of America; Neuroscience Program, Michigan State University, United States of America
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Gao WR, Hu XH, Yu KY, Cai HY, Wang ZJ, Wang L, Wu MN. Selective orexin 1 receptor antagonist SB-334867 aggravated cognitive dysfunction in 3xTg-AD mice. Behav Brain Res 2023; 438:114171. [PMID: 36280008 DOI: 10.1016/j.bbr.2022.114171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/09/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022]
Abstract
Cognitive dysfunction is the main clinical manifestation of Alzheimer's disease (AD). Previous research found that elevated orexin level in the cerebrospinal fluid was closely related to the course of AD, and orexin-A treatment could increase amyloid β protein (Aβ) deposition and aggravate spatial memory impairment in APP/PS1 mice. Furthermore, recent research found that dual orexin receptor (OXR) antagonist might affect Aβ level and cognitive dysfunction in AD, but the effects of OX1R or OX2R alone is unreported until now. Considering that OX1R is highly expressed in the hippocampus and plays important roles in learning and memory, the effects of OX1R in AD cognitive dysfunction and its possible mechanism should be investigated. In the present study, selective OX1R antagonist SB-334867 was used to block OX1R. Then, different behavioral tests were performed to observe the effects of OX1R blockade on cognitive function of 3xTg-AD mice exhibited both Aβ and tau pathology, in vivo electrophysiological recording and western blot were used to investigate the potential mechanism. The results showed that chronic OX1R blockade aggravated the impairments of short-term working memory, long-term spatial memory and synaptic plasticity in 9-month-old female 3xTg-AD mice, increased levels of soluble Aβ oligomers and p-tau, and decreased PSD-95 expression in the hippocampus of 3xTg-AD mice. These results indicate that the detrimental effects of SB-334867 on cognitive behaviors in 3xTg-AD mice are closely related to the decrease of PSD-95 and depression of in vivo long-term potentiation (LTP) caused by increased Aβ oligomers and p-tau.
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Affiliation(s)
- Wen-Rui Gao
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Xiao-Hong Hu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Kai-Yue Yu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Hong-Yan Cai
- Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan 030001, China
| | - Zhao-Jun Wang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Lei Wang
- Department of Geriatrics, Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan 030032, China.
| | - Mei-Na Wu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China.
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