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Ullah R, Lee EJ. Advances in Amyloid-β Clearance in the Brain and Periphery: Implications for Neurodegenerative Diseases. Exp Neurobiol 2023; 32:216-246. [PMID: 37749925 PMCID: PMC10569141 DOI: 10.5607/en23014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/25/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023] Open
Abstract
This review examines the role of impaired amyloid-β clearance in the accumulation of amyloid-β in the brain and the periphery, which is closely associated with Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). The molecular mechanism underlying amyloid-β accumulation is largely unknown, but recent evidence suggests that impaired amyloid-β clearance plays a critical role in its accumulation. The review provides an overview of recent research and proposes strategies for efficient amyloid-β clearance in both the brain and periphery. The clearance of amyloid-β can occur through enzymatic or non-enzymatic pathways in the brain, including neuronal and glial cells, blood-brain barrier, interstitial fluid bulk flow, perivascular drainage, and cerebrospinal fluid absorption-mediated pathways. In the periphery, various mechanisms, including peripheral organs, immunomodulation/immune cells, enzymes, amyloid-β-binding proteins, and amyloid-β-binding cells, are involved in amyloid-β clearance. Although recent findings have shed light on amyloid-β clearance in both regions, opportunities remain in areas where limited data is available. Therefore, future strategies that enhance amyloid-β clearance in the brain and/or periphery, either through central or peripheral clearance approaches or in combination, are highly encouraged. These strategies will provide new insight into the disease pathogenesis at the molecular level and explore new targets for inhibiting amyloid-β deposition, which is central to the pathogenesis of sporadic AD (amyloid-β in parenchyma) and CAA (amyloid-β in blood vessels).
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Affiliation(s)
- Rahat Ullah
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Neurology, School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA
| | - Eun Jeong Lee
- Department of Brain Science, Ajou University School of Medicine, Suwon 16499, Korea
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2
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Xu Y, Yang B, Hui J, Zhang C, Bian X, Tao M, Lu Y, Wang W, Qian H, Shang Z. The emerging role of sacubitril/valsartan in pulmonary hypertension with heart failure. Front Cardiovasc Med 2023; 10:1125014. [PMID: 37273885 PMCID: PMC10233066 DOI: 10.3389/fcvm.2023.1125014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 05/04/2023] [Indexed: 06/06/2023] Open
Abstract
Pulmonary hypertension due to left heart disease (PH-LHD) represents approximately 65%-80% of all patients with PH. The progression, prognosis, and mortality of individuals with left heart failure (LHF) are significantly influenced by PH and right ventricular (RV) dysfunction. Consequently, cardiologists should devote ample attention to the interplay between HF and PH. Patients with PH and HF may not receive optimal benefits from the therapeutic effects of prostaglandins, endothelin receptor antagonists, or phosphodiesterase inhibitors, which are specific drugs for pulmonary arterial hypertension (PAH). Sacubitril/valsartan, the angiotensin receptor II blocker-neprilysin inhibitor (ARNI), was recommended as the first-line therapy for patients with heart failure with reduced ejection fraction (HFrEF) by the 2021 European Society of Cardiology Guidelines. Although ARNI is effective in treating left ventricular (LV) enlargement and lower ejection fraction, its efficacy in treating individuals with PH and HF remains underexplored. Considering its vasodilatory effect at the pre-capillary level and a natriuretic drainage role at the post-capillary level, ARNI is believed to have a broad range of potential applications in treating PH-LHD. This review discusses the fundamental pathophysiological connections between PH and HF, emphasizing the latest research and potential benefits of ARNI in PH with various types of LHF and RV dysfunction.
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3
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Guo X, Jiang Q, Li Z, Cheng C, Feng Y, He Y, Zuo L, Ding W, Zhang D, Feng L. Crystal structural analysis and characterization for MlrC enzyme of Sphingomonas sp. ACM-3962 involved in linearized microcystin degradation. CHEMOSPHERE 2023; 317:137866. [PMID: 36642149 DOI: 10.1016/j.chemosphere.2023.137866] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/28/2022] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Microcystinase C (MlrC), one key hydrolase of the microcystinase family, plays an important role in linearized microsystin (L-MC) degradation. However, the three-dimensional structure and structural features of MlrC are still unclear. This study obtained high specific activity and high purity of MlrC by heterologous expression, and revealed that MlrC derived from Sphingomonas sp. ACM-3962 (ACM-MlrC) can degrade linearized products of MC-LR, MC-RR and MC-YR to product 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda), indicating the degradation function and significance in MC-detoxification. More importantly, this study reported the crystal structure of ACM-MlrC at 2.6 Å resolution for the first time, which provides a basis for further understanding the structural characteristics and functions of MlrC. MlrC had a dual-domain feature, namely N and C terminal domain respectively. The N-terminal domain contained a Glutamate-Aspartate-Histidine-Histidine catalytic quadruplex coordinated with zinc ion in each monomer. The importance of zinc ions and their coordinated residues was analyzed by dialysis and site-directed mutagenesis methods. Moreover, the important influence of the N/C-terminal flexible regions of ACM-MlrC was also analyzed by sequence truncation, and then the higher yield and total activity of variants were obtained, which was beneficial to study the better function and application of MlrC.
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Affiliation(s)
- Xiaoliang Guo
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Qinqin Jiang
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Zengru Li
- The Institute of Physics, Chinese Academy of Sciences, P.O.Box 603, Beijing, 100190, China
| | - Cai Cheng
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Yu Feng
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Yanlin He
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Lingzi Zuo
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Wei Ding
- The Institute of Physics, Chinese Academy of Sciences, P.O.Box 603, Beijing, 100190, China
| | - Delin Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Lingling Feng
- Key Laboratory of Pesticide & Chemical Biology (CCNU), Ministry of Education; College of Chemistry, Central China Normal University, Wuhan, 430079, China.
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Chen J, Li SS, Fang SM, Zhang Z, Yu QY. Olfactory dysfunction and potential mechanisms caused by volatile organophosphate dichlorvos in the silkworm as a model animal. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127940. [PMID: 34896704 DOI: 10.1016/j.jhazmat.2021.127940] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/25/2021] [Accepted: 11/25/2021] [Indexed: 06/14/2023]
Abstract
Volatile pesticides impair olfactory function in workers/farmers and insects, but data on molecular responses and mechanisms are poorly understood. This study aims to reveal the mechanisms of olfactory dysfunction in the silkworm after exposure to volatile dichlorvos. Our results demonstrated that acute exposure for 12 h significantly reduced electroantennogram responses, and over 62.50% of the treated male moths cannot locate the pheromone source. Transcriptional and proteomic responses of the antennae and heads were investigated. A total of 101 differentially expressed genes (DEGs) in the antennae, 138 DEGs in the heads, and 43 differentially expressed proteins (DEPs) in the heads including antennae were revealed. We discovered that upregulations of Arrestin1 and nitric oxide synthase1 (NOS1) may inhibit cyclic nucleotide-gated channels and hinder calcium influx in the antennae. In the central nervous systems (CNS), downregulations of tyrosine hydroxylase (TH) and tyrosine decarboxylase (TDC) may inhibit olfactory signal transduction by reducing the second messenger biosynthesis. Meanwhile, an abnormal increase of brain cell apoptosis was revealed by Annexin V-mCherry staining, often leading to persistent neurologic impairment. Taken together, this study highlighted olfactory dysfunction caused by dichlorvos, which may provide a novel perspective for understanding the toxicity mechanism of volatile pesticides in other organisms.
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Affiliation(s)
- Jie Chen
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China
| | - Shu-Shang Li
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China
| | - Shou-Min Fang
- College of Life Science, China West Normal University, Nanchong 637002, Sichuan, China
| | - Ze Zhang
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China
| | - Quan-You Yu
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China.
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Vasilev DS, Dubrovskaya NМ, Tumanova NL, Nalivaeva NN. Analysis of Expression of the Amyloid-Degrading Enzyme Neprilysin in Brain Structures of 5xFAD Transgenic Mice. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022010173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Qian C, Yang C, Lu M, Bao J, Shen H, Deng B, Li S, Li W, Zhang M, Cao C. Activating AhR alleviates cognitive deficits of Alzheimer's disease model mice by upregulating endogenous Aβ catabolic enzyme Neprilysin. Theranostics 2021; 11:8797-8812. [PMID: 34522212 PMCID: PMC8419060 DOI: 10.7150/thno.61601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/02/2021] [Indexed: 02/07/2023] Open
Abstract
Rationale: Neprilysin (NEP) is a major endogenous catabolic enzyme of amyloid β (Aβ). Previous studies have suggested that increasing NEP expression in animal models of Alzheimer's disease had an ameliorative effect. However, the underlying signaling pathway that regulates NEP expression remains unclear. The aryl hydrocarbon receptor (AhR) is a ligand-activated cytoplasmic receptor and transcription factor. Recent studies have shown that AhR plays essential roles in the central nervous system (CNS), but its physiological and pathological roles in regulating NEP are not entirely known. Methods: Western blotting, immunofluorescence, quantitative RT-PCR and enzyme activity assay were used to verify the effects of AhR agonists on NEP in a cell model (N2a) and a mouse model (APP/PS1). Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were conducted to investigate the roles of AhR in regulating NEP transcription. Object recognition test and the Morris water maze task were performed to assess the cognitive capacity of the mice. Results: Activating AhR by the endogenous ligand L-Kynurenine (L-KN) or FICZ, or by the exogenous ligand diosmin or indole-3-carbinol (I3C) significantly increases NEP expression and enzyme activity in N2a cells and APP/PS1 mice. We also found that AhR is a direct transcription factor of NEP. Diosmin treatment effectively ameliorated the cognitive disorder and memory deficit of APP/PS1 transgenic mice. By knocking down AhR or using a small molecular inhibitor targeting AhR or NEP, we found that diosmin enhanced Aβ degradation through activated AhR and increased NEP expression. Conclusions: These results indicate a novel pathway for regulating NEP expression in neurons and that AhR may be a potential therapeutic target for the treatment of Alzheimer's disease.
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Kuang H, Huang X, Zhou Z, Cheng X, Xu G. Sacubitril/valsartan in chronic kidney disease: From pharmacological mechanism to clinical application. Eur J Pharmacol 2021; 907:174288. [PMID: 34216577 DOI: 10.1016/j.ejphar.2021.174288] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/08/2021] [Accepted: 06/25/2021] [Indexed: 02/08/2023]
Abstract
Chronic kidney disease (CKD) is an irreversible, progressive disease characterized by persistent kidney damage, and significantly increased risks of cardiovascular event. However, therapeutic strategies to prevent or slow the progression of CKD remain limited. Sacubitril/valsartan (LCZ696), the representative of the first novel angiotensin receptor-neprilysin inhibitor, has been incorporated into clinical practice guidelines for improving outcomes as a milestone in patients with heart failure. Considering the complex and close relationship between CKD and heart failure, LCZ696 may be beneficial in the treatment of CKD. This review summarizes the pharmacological mechanism and clinical application of LCZ696 in patients with CKD, including its effect on cardiovascular risk and renal outcome, together with potential adverse events. Additionally, due to the influence of serum creatinine and estimated glomerular filtration rate on LCZ696 in patients with heart failure, we also discussed the effects of LCZ696 in patients with advanced CKD and end-stage renal disease. It should be noted that, current clinical studies on LCZ696 are mostly carried out in patients with heart failure, and renal indicators are selected as secondary outcomes. Therefore, more researches should be conducted in patients with CKD alone in the future, to determine the efficacy and safety of LCZ696 in patients with CKD.
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Affiliation(s)
- Huang Kuang
- Renal Division, Peking University First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, 100034, China
| | - Xin Huang
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Zhifeng Zhou
- Department of Nephrology, Kidney Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Xuexin Cheng
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
| | - Gaosi Xu
- Department of Nephrology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
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8
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Meyer H, Buhr A, Callaerts P, Schiemann R, Wolfner MF, Marygold SJ. Identification and bioinformatic analysis of neprilysin and neprilysin-like metalloendopeptidases in Drosophila melanogaster. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000410. [PMID: 34189422 PMCID: PMC8223033 DOI: 10.17912/micropub.biology.000410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The neprilysin (M13) family of metalloendopeptidases comprises highly conserved ectoenzymes that cleave and thereby inactivate many physiologically relevant peptides in the extracellular space. Impaired neprilysin activity is associated with numerous human diseases. Here, we present a comprehensive list and classification of M13 family members in Drosophila melanogaster. Seven Neprilysin (Nep) genes encode active peptidases, while 21 Neprilysin-like (Nepl) genes encode proteins predicted to be catalytically inactive. RNAseq data demonstrate that all 28 genes are expressed during development, often in a tissue-specific pattern. Most Nep proteins possess a transmembrane domain, whereas almost all Nepl proteins are predicted to be secreted.
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Affiliation(s)
- Heiko Meyer
- Department of Zoology & Developmental Biology, Osnabrück University, 49076 Osnabrück, Germany,
Correspondence to: Heiko Meyer (); Steven J. Marygold ()
| | - Annika Buhr
- Department of Zoology & Developmental Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Patrick Callaerts
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KULeuven, University of Leuven, B-3000 Leuven, Belgium
| | - Ronja Schiemann
- Department of Zoology & Developmental Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Mariana F. Wolfner
- Department of Molecular Biology & Genetics, Cornell University, Ithaca NY 14853 USA
| | - Steven J. Marygold
- FlyBase, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3DY, U.K.,
Correspondence to: Heiko Meyer (); Steven J. Marygold ()
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Hernandez AR, Banerjee A, Carter CS, Buford TW. Angiotensin (1-7) Expressing Probiotic as a Potential Treatment for Dementia. FRONTIERS IN AGING 2021; 2:629164. [PMID: 34901930 PMCID: PMC8663799 DOI: 10.3389/fragi.2021.629164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/05/2021] [Indexed: 12/12/2022]
Abstract
Increasing life expectancies are unfortunately accompanied by increased prevalence of Alzheimer's disease (AD). Regrettably, there are no current therapeutic options capable of preventing or treating AD. We review here data indicating that AD is accompanied by gut dysbiosis and impaired renin angiotensin system (RAS) function. Therefore, we propose the potential utility of an intervention targeting both the gut microbiome and RAS as both are heavily involved in proper CNS function. One potential approach which our group is currently exploring is the use of genetically-modified probiotics (GMPs) to deliver therapeutic compounds. In this review, we specifically highlight the potential utility of utilizing a GMP to deliver Angiotensin (1-7), a beneficial component of the renin-angiotensin system with relevant functions in circulation as well as locally in the gut and brain.
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Affiliation(s)
- Abbi R. Hernandez
- Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Anisha Banerjee
- Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christy S. Carter
- Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Integrative Center for Aging Research, University of Alabama at Birmingham, Birmingham, AL, United States
- Nathan Shock Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Thomas W. Buford
- Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Integrative Center for Aging Research, University of Alabama at Birmingham, Birmingham, AL, United States
- Nathan Shock Center, University of Alabama at Birmingham, Birmingham, AL, United States
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10
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Drosophila Middle-Term Memory: Amnesiac is Required for PKA Activation in the Mushroom Bodies, a Function Modulated by Neprilysin 1. J Neurosci 2020; 40:4219-4229. [PMID: 32303647 DOI: 10.1523/jneurosci.2311-19.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 03/30/2020] [Accepted: 04/05/2020] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, the mushroom bodies (MB) constitute the central brain structure for olfactory associative memory. As in mammals, the cAMP/PKA pathway plays a key role in memory formation. In the MB, Rutabaga (Rut) adenylate cyclase acts as a coincidence detector during associative conditioning to integrate calcium influx resulting from acetylcholine stimulation and G-protein activation resulting from dopaminergic stimulation. Amnesiac encodes a secreted neuropeptide required in the MB for two phases of aversive olfactory memory. Previous sequence analysis has revealed strong homology with the mammalian pituitary adenylate cyclase-activating peptide (PACAP). Here, we examined whether amnesiac is involved in cAMP/PKA dynamics in response to dopamine and acetylcholine co-stimulation in living flies. Experiments were conducted with both sexes, or with either sex. Our data show that amnesiac is necessary for the PKA activation process that results from coincidence detection in the MB. Since PACAP peptide is cleaved by the human membrane neprilysin hNEP, we searched for an interaction between Amnesiac and Neprilysin 1 (Nep1), a fly neprilysin involved in memory. We show that when Nep1 expression is acutely knocked down in adult MB, memory deficits displayed by amn hypomorphic mutants are rescued. Consistently, Nep1 inhibition also restores normal PKA activation in amn mutant flies. Taken together, the results suggest that Nep1 targets Amnesiac degradation to terminate its signaling function. Our work thus highlights a key role for Amnesiac in establishing within the MB the PKA dynamics that sustain middle-term memory (MTM) formation, a function modulated by Nep1.SIGNIFICANCE STATEMENT The Drosophila amnesiac gene encodes a secreted neuropeptide whose expression is required for specific memory phases in the mushroom bodies (MB), the olfactory memory center. Here, we show that Amnesiac is required for PKA activation resulting from coincidence detection, a mechanism by which the MB integrate two spatially distinct stimuli to encode associative memory. Furthermore, our results uncover a functional relationship between Amnesiac and Neprilysin 1 (Nep1), a membrane peptidase involved in memory and expressed in the MB. These results suggest that Nep1 modulates Amnesiac levels. We propose that on conditioning, Amnesiac release from the MB allows, via an autocrine process, the sustaining of PKA activation-mediating memory, which subsequently is inactivated by Nep1 degradation.
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Silva B, Niehage C, Maglione M, Hoflack B, Sigrist SJ, Wassmer T, Pavlowsky A, Preat T. Interactions between amyloid precursor protein-like (APPL) and MAGUK scaffolding proteins contribute to appetitive long-term memory in Drosophila melanogaster. J Neurogenet 2020; 34:92-105. [PMID: 31965876 DOI: 10.1080/01677063.2020.1712597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Amyloid precursor protein (APP), the precursor of amyloid beta peptide, plays a central role in Alzheimer's disease (AD), a pathology characterized by memory decline and synaptic loss upon aging. Understanding the physiological role of APP is fundamental in deciphering the progression of AD, and several studies suggest a synaptic function via protein-protein interactions. Nevertheless, it remains unclear whether and how these interactions contribute to memory. In Drosophila, we previously showed that APP-like (APPL), the fly APP homolog, is required for aversive associative memory in the olfactory memory center, the mushroom body (MB). In the present study, we show that APPL is required for appetitive long-term memory (LTM), another form of associative memory, in a specific neuronal subpopulation of the MB, the α'/β' Kenyon cells. Using a biochemical approach, we identify the synaptic MAGUK (membrane-associated guanylate kinase) proteins X11, CASK, Dlgh2 and Dlgh4 as interactants of the APP intracellular domain (AICD). Next, we show that the Drosophila homologs CASK and Dlg are also required for appetitive LTM in the α'/β' neurons. Finally, using a double RNAi approach, we demonstrate that genetic interactions between APPL and CASK, as well as between APPL and Dlg, are critical for appetitive LTM. In summary, our results suggest that APPL contributes to associative long-term memory through its interactions with the main synaptic scaffolding proteins CASK and Dlg. This function should be conserved across species.
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Affiliation(s)
- Bryon Silva
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | | | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | | | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Thomas Wassmer
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Alice Pavlowsky
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Thomas Preat
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
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Quan Q, Qian Y, Li X, Li M. Pioglitazone Reduces β Amyloid Levels via Inhibition of PPARγ Phosphorylation in a Neuronal Model of Alzheimer's Disease. Front Aging Neurosci 2019; 11:178. [PMID: 31379559 PMCID: PMC6650543 DOI: 10.3389/fnagi.2019.00178] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/02/2019] [Indexed: 12/28/2022] Open
Abstract
It has been demonstrated that peroxisome proliferator-activated receptor γ (PPARγ) can regulate the transcription of its target gene, insulin-degrading enzyme (IDE), and thus enhance the expression of the IDE protein. The protein can degrade β amyloid (Aβ), a core pathological product of Alzheimer’s disease (AD). PPARγ can also regulate the transcription of other target gene, β-amyloid cleavage enzyme 1 (BACE1), and thus inhibit the expression of the BACE1 protein. BACE1 can hydrolyze amyloid precursor protein (APP), the precursor of Aβ. In adipose tissue, PPARγ agonists can inhibit the phosphorylation of PPARγ by inhibiting cyclin-dependent kinase 5 (CDK5), which in turn affects the expression of target genes regulated by PPARγ. PPARγ agonists may also exert inhibitory effects on the phosphorylation of PPARγ in the brain, thereby affecting the expression of the aforementioned PPARγ target genes and reducing Aβ levels. The present study confirmed this hypothesis by showing that PPARγ agonist pioglitazone attenuated the neuronal apoptosis of primary rat hippocampal neurons induced by Aβ1–42, downregulated CDK5 expression, weakened the binding of CDK5 to PPARγ, reduced PPARγ phosphorylation, increased the expression of PPARγ and IDE, decreased the expression of BACE1, reduced APP production, and downregulated intraneuronal Aβ1–42 levels. These effects were inhibited by the PPARγ antagonist GW9662. After CDK5 silencing with CDK5 shRNA, the above effect of pioglitazone was not observed, except when upregulating the expression of PPARγ in Aβ1–42 treated neurons. In conclusion, this study demonstrated that pioglitazone could inhibit the phosphorylation of PPARγ in vitro by inhibiting CDK5 expression, which in turn affected the expression of PPARγ target genes Ide and Bace1, thereby promoting Aβ degradation and reducing Aβ production. This reduced Aβ levels in the brain, thereby exerting neuroprotective effects in an AD model.
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Affiliation(s)
- Qiankun Quan
- Department of Geriatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.,Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Yihua Qian
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Xi Li
- Department of Geriatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ming Li
- Department of Geriatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Papanikolopoulou K, Mudher A, Skoulakis E. An assessment of the translational relevance of Drosophila in drug discovery. Expert Opin Drug Discov 2019; 14:303-313. [PMID: 30664368 DOI: 10.1080/17460441.2019.1569624] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Drosophila melanogaster offers a powerful expedient and economical system with facile genetics. Because of the high sequence and functional conservation with human disease-associated genes, it has been cardinal in deciphering disease mechanisms at the genetic and molecular level. Drosophila are amenable to and respond well to pharmaceutical treatment which coupled to their genetic tractability has led to discovery, repositioning, and validation of a number of compounds. Areas covered: This review summarizes the generation of fly models of human diseases, their advantages and use in elucidation of human disease mechanisms. Representative studies provide examples of the utility of this system in modeling diseases and the discovery, repositioning and testing on pharmaceuticals to ameliorate them. Expert opinion: Drosophila offers a facile and economical whole animal system with many homologous organs to humans, high functional conservation and established methods of generating and validating human disease models. Nevertheless, it remains relatively underused as a drug discovery tool probably because its relevance to mammalian systems remains under question. However, recent exciting success stories using Drosophila disease models for drug screening, repositioning and validation strongly suggest that fly models should figure prominently in the drug discovery pipeline from bench to bedside.
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Affiliation(s)
- Katerina Papanikolopoulou
- a Division of Neuroscience , Biomedical Sciences Research Centre "Alexander Fleming" , Vari , Greece
| | - Amrit Mudher
- b Centre for Biological Sciences , University of Southampton , Southampton , UK
| | - Efthimios Skoulakis
- a Division of Neuroscience , Biomedical Sciences Research Centre "Alexander Fleming" , Vari , Greece
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