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Chen R, Wang Z, Lin Q, Hou X, Jiang Y, Le Q, Liu X, Ma L, Wang F. Destabilization of fear memory by Rac1-driven engram-microglia communication in hippocampus. Brain Behav Immun 2024; 119:621-636. [PMID: 38670239 DOI: 10.1016/j.bbi.2024.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 04/28/2024] Open
Abstract
Rac1 is a key regulator of the cytoskeleton and neuronal plasticity, and is known to play a critical role in psychological and cognitive brain disorders. To elucidate the engram specific Rac1 signaling in fear memory, a doxycycline (Dox)-dependent robust activity marking (RAM) system was used to label dorsal dentate gyrus (DG) engram cells in mice during contextual fear conditioning. Rac1 mRNA and protein levels in DG engram cells were peaked at 24 h (day 1) after fear conditioning and were more abundant in the fear engram cells than in the non-engram cells. Optogenetic activation of Rac1 in a temporal manner in DG engram cells before memory retrieval decreased the freezing level in the fear context. Optogenetic activation of Rac1 increased autophagy protein 7 (ATG7) expression in the DG engram cells and activated DG microglia. Microglia-specific transcriptomics and fluorescence in situ hybridization revealed that overexpression of ATG7 in the fear engram cells upregulated the mRNA of Toll-like receptor TLR2/4 in DG microglia. Knockdown of microglial TLR2/4 rescued fear memory destabilization induced by ATG7 overexpression or Rac1 activation in DG engram cells. These results indicate that Rac1-driven communications between engram cells and microglia contributes to contextual fear memory destabilization, and is mediated by ATG7 and TLR2/4, and suggest a novel mechanistic framework for the cytoskeletal regulator in fear memory interference.
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Affiliation(s)
- Ruyan Chen
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Zhilin Wang
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Qing Lin
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Xutian Hou
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Yan Jiang
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Qiumin Le
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Xing Liu
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Lan Ma
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China
| | - Feifei Wang
- School of Basic Medicine Sciences, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Pharmacology Research Center, Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200032, China; Research Unit of Addition Memory, Chinese Academy of Medical Sciences (2021RU009), Shanghai 200032, China.
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Hsieh TC, Chiang HC. IMD signaling in the gut and the brain modulates Amyloid-beta-induced deficits in Drosophila. Life Sci 2023; 332:122118. [PMID: 37741318 DOI: 10.1016/j.lfs.2023.122118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/12/2023] [Accepted: 09/20/2023] [Indexed: 09/25/2023]
Abstract
AIMS Evidence indicates accumulating Aβ peptides in brain activates immune responses in neuronal and peripheral system, which may collaboratively influence pathogenesis of Alzheimer's disease (AD). We aim to investigate whether regulating intestinal innate immune signaling ameliorates Aβ-induced impairments in Drosophila melanogaster. MAIN METHODS Quantitative polymerase chain reaction (qPCR) was used to observe expression changes of innate immune responses related genes in brain and in gut under the circumstance of Aβ overexpressing in nerve system. Aversive olfactory conditioning and survival assay were used to investigate effects of modulating Attacin-A (AttA) and Dpitercin-A (DptA). Fluorometric assays of respiratory burst activity was introduced to explore whether reducing oxidative stress enables overexpressing intestinal AttA and DptA to reverse Aβ-induced deficits. KEY FINDINGS In vivo genetic analysis revealed that accumulating Aβ42 in neurons modulates innate immune signaling of the IMD pathway both in the brain and in the gut. Increased expression levels of the intestinal AttA and DptA improved learning performance and extended the lifespan of Aβ42 flies. The administration of apramycin led to alleviations of Aβ-induced behavioral changes, indicating that gram-negative bacteria are associated with the development of Aβ-induced pathologies. Further analysis showed that the neural expression of Aβ42 increased oxidative stress in the gut, which disrupted intestinal integrity and decreased learning performance. In addition, increased levels of AMPs targeting gram-negative bacteria and antioxidants reduced oxidative stress in the gut and reversed Aβ-induced behavioral damage. SIGNIFICANCE These findings suggest that innate immune responses in the gut play a pivotal role in modulating Aβ-induced pathologies.
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Affiliation(s)
- Tsung-Chi Hsieh
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hsueh-Cheng Chiang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Pharmacology, National Cheng Kung University, Tainan, Taiwan.
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Wang W, Wang Z, Cao J, Dong Y, Chen Y. Roles of Rac1-Dependent Intrinsic Forgetting in Memory-Related Brain Disorders: Demon or Angel. Int J Mol Sci 2023; 24:10736. [PMID: 37445914 DOI: 10.3390/ijms241310736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Animals are required to handle daily massive amounts of information in an ever-changing environment, and the resulting memories and experiences determine their survival and development, which is critical for adaptive evolution. However, intrinsic forgetting, which actively deletes irrelevant information, is equally important for memory acquisition and consolidation. Recently, it has been shown that Rac1 activity plays a key role in intrinsic forgetting, maintaining the balance of the brain's memory management system in a controlled manner. In addition, dysfunctions of Rac1-dependent intrinsic forgetting may contribute to memory deficits in neurological and neurodegenerative diseases. Here, these new findings will provide insights into the neurobiology of memory and forgetting, pathological mechanisms and potential therapies for brain disorders that alter intrinsic forgetting mechanisms.
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Affiliation(s)
- Wei Wang
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Zixu Wang
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Jing Cao
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yulan Dong
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yaoxing Chen
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, Beijing Laboratory of Food Quality and Safety, Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
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Wu Q, Su S, Cai C, Xu L, Fan X, Ke H, Dai Z, Fang S, Zhuo Y, Wang Q, Pan H, Gu Y, Fang J. Network Proximity-based computational pipeline identifies drug candidates for different pathological stages of Alzheimer's disease. Comput Struct Biotechnol J 2023; 21:1907-1920. [PMID: 36936813 PMCID: PMC10015208 DOI: 10.1016/j.csbj.2023.02.041] [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: 09/15/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 02/26/2023] Open
Abstract
Despite the massive investment in Alzheimer's disease (AD), there are still no disease-modifying treatments (DMTs) for AD. One major reason is attributed to the limitation of clinical "one-size-fits-all" approach, since the same AD treatment solely based on clinical diagnosis was unlikely to achieve good clinical efficacy. In recent years, computational approaches based on multiomics data have provided an unprecedented opportunity for drug discovery since they can substantially lower the costs and boost the efficiency. In this study, we intended to identify potential drug candidates for different pathological stages of AD by computationally repurposing Food and Drug Administration (FDA) approved drugs. First, we assembled gene expression data from three different AD pathological stages, which include mild cognitive impairment (MCI) and early and late stages of AD (EAD, LAD). We next quantified the network distances between drug target networks and AD modules by utilizing a network proximity approach, and identified 193 candidates that possessed significant associations with AD. After searching for previous literature evidence, 63 out of 193 (32.6%) predicted drugs were demonstrated to exert therapeutic effects on AD. We further explored the novel mechanism of action (MOA) for these drug candidates by determining the specific brain cells they might function on based on AD patient single cell transcriptomic data. Additionally, we selected several promising candidates that could cross the blood brain barrier together with confirmed neuroprotective effects, and subsequently determined the antioxidative activity of these compounds. Experimental results showed that azathioprine decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) levels and improved the superoxide dismutase (SOD) activity in APP-SH-SY5Y cells. Finally, we deciphered the potential MOA of azathioprine against AD via network analysis and validated several apoptosis-related proteins (Caspase 3, Cleaved Caspase 3, Bax, Bcl2) through western blotting. In summary, this study presented an effective computational strategy utilizing omics data for AD drug repurposing, which provides a new perspective for drug discovery and development.
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Affiliation(s)
- Qihui Wu
- Clinical Research Center, Hainan Provincial Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, Haikou, China
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
- Hainan Clinical Center for Encephalopathy of Chinese Medicine, Haikou, China
- Hainan Clinical Research Center for Preventive Treatment of Diseases, Haikou, China
| | - Shijie Su
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Chuipu Cai
- Department of Computer Science, Key Laboratory of Intelligent Manufacturing Technology of Ministry of Education, Shantou University, Shantou, China
| | - Lina Xu
- Department of Cardiac Surgery, Qingdao Fuwai Cardiovascular Hospital, Qingdao, China
| | - Xiude Fan
- Department of Infectious Diseases, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Hanzhong Ke
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, United States
| | - Zhao Dai
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shuhuan Fang
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yue Zhuo
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qi Wang
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Huafeng Pan
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yong Gu
- Clinical Research Center, Hainan Provincial Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, Haikou, China
- Hainan Clinical Center for Encephalopathy of Chinese Medicine, Haikou, China
- Hainan Clinical Research Center for Preventive Treatment of Diseases, Haikou, China
- Corresponding author at: Clinical Research Center, Hainan Provincial Hospital of Traditional Chinese Medicine, Guangzhou University of Chinese Medicine, Haikou, China.
| | - Jiansong Fang
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
- Corresponding author.
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Dhamodharan J, Sekhar G, Muthuraman A. Epidermal Growth Factor Receptor Kinase Inhibitor Ameliorates β-Amyloid Oligomer-Induced Alzheimer Disease in Swiss Albino Mice. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27165182. [PMID: 36014421 PMCID: PMC9412386 DOI: 10.3390/molecules27165182] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/04/2022] [Accepted: 08/11/2022] [Indexed: 11/16/2022]
Abstract
Alzheimer's disease (AD) is one of the major neurodegenerative disorders, and its incidence increases globally every year. Currently, available AD drugs symptomatically treat AD with multiple adverse effects. Gefitinib (GE) is an epidermal growth factor receptor (EGFR) kinase inhibitor. EGFR is the preferred target for the treatment of AD, whereas the effect of GE in AD conditions is limited. The present study was designed to explore the ameliorative potential of GE in Aβ1-42 oligomer-induced neurotoxicity in AD mice. AD was induced by intracerebroventricular (i.c.v.) injection of Aβ1-42 oligomer (4 μg/4 μL) into the lateral ventricles of the mouse brain. The test compound, i.e., GE (2 and 4 mg/kg of body weight), was administered orally on days 10, 13, 16, 19, 22, 25, and 28, and the reference drug, i.e., donepezil (DP, 2 mg/kg), was administered orally from the 10th to 28th days. The behavioral changes were screened by the Morris water maze (MWM) test. Furthermore, biomarkers i.e., brain acetylcholinesterase (AChE), thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH) levels were estimated from brain samples. The AD-associated histopathological changes were analyzed by hematoxylin and eosin staining. The administration of GE significantly ameliorated the AD-associated behavioral, biochemical, and histopathological changes. The ameliorative effect of GE against the Aβ1-42 oligomer-associated neurotoxicity was due to its potent inhibition of EGFR kinase activation, as well as its antioxidant and antilipid peroxidative effect.
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Affiliation(s)
- Jagadeesh Dhamodharan
- Unit of Anatomy, Faculty of Medicine, AIMST University, Semeling, Bedong 08100, Kedah, Malaysia
- Department of Pathology, Faculty of Medicine, Saveetha Institute of Medical & Technical Sciences (SIMATS), Saveetha University, Chennai 602105, Tamilnadu, India
| | - Ganthimathy Sekhar
- Department of Pathology, Faculty of Medicine, Saveetha Institute of Medical & Technical Sciences (SIMATS), Saveetha University, Chennai 602105, Tamilnadu, India
| | - Arunachalam Muthuraman
- Unit of Pharmacology, Faculty of Pharmacy, AIMST University, Bedong 08100, Kedah, Malaysia
- Correspondence:
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