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Gwin MS, Alexeyev MF, Geurts AM, Lee JY, Zhou C, Yang XM, Cohen MV, Downey JM, Barrington RA, Spadafora D, Audia JP, Frank DW, Voth S, Pastukh VV, Bell J, Ayers L, Tambe DT, Nelson AR, Balczon R, Lin MT, Stevens T. Gamma secretase activating protein promotes end-organ dysfunction after bacterial pneumonia. Am J Physiol Lung Cell Mol Physiol 2023; 325:L174-L189. [PMID: 37366533 PMCID: PMC10396227 DOI: 10.1152/ajplung.00018.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023] Open
Abstract
Pneumonia elicits the production of cytotoxic beta amyloid (Aβ) that contributes to end-organ dysfunction, yet the mechanism(s) linking infection to activation of the amyloidogenic pathway that produces cytotoxic Aβ is unknown. Here, we tested the hypothesis that gamma-secretase activating protein (GSAP), which contributes to the amyloidogenic pathway in the brain, promotes end-organ dysfunction following bacterial pneumonia. First-in-kind Gsap knockout rats were generated. Wild-type and knockout rats possessed similar body weights, organ weights, circulating blood cell counts, arterial blood gases, and cardiac indices at baseline. Intratracheal Pseudomonas aeruginosa infection caused acute lung injury and a hyperdynamic circulatory state. Whereas infection led to arterial hypoxemia in wild-type rats, the alveolar-capillary barrier integrity was preserved in Gsap knockout rats. Infection potentiated myocardial infarction following ischemia-reperfusion injury, and this potentiation was abolished in knockout rats. In the hippocampus, GSAP contributed to both pre- and postsynaptic neurotransmission, increasing the presynaptic action potential recruitment, decreasing neurotransmitter release probability, decreasing the postsynaptic response, and preventing postsynaptic hyperexcitability, resulting in greater early long-term potentiation but reduced late long-term potentiation. Infection abolished early and late long-term potentiation in wild-type rats, whereas the late long-term potentiation was partially preserved in Gsap knockout rats. Furthermore, hippocampi from knockout rats, and both the wild-type and knockout rats following infection, exhibited a GSAP-dependent increase in neurotransmitter release probability and postsynaptic hyperexcitability. These results elucidate an unappreciated role for GSAP in innate immunity and highlight the contribution of GSAP to end-organ dysfunction during infection.NEW & NOTEWORTHY Pneumonia is a common cause of end-organ dysfunction, both during and in the aftermath of infection. In particular, pneumonia is a common cause of lung injury, increased risk of myocardial infarction, and neurocognitive dysfunction, although the mechanisms responsible for such increased risk are unknown. Here, we reveal that gamma-secretase activating protein, which contributes to the amyloidogenic pathway, is important for end-organ dysfunction following infection.
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Affiliation(s)
- Meredith S Gwin
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mikhail F Alexeyev
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Aron M Geurts
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Ji Young Lee
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Chun Zhou
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Xi-Ming Yang
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Michael V Cohen
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - James M Downey
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Robert A Barrington
- Department of Microbiology and Immunology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Domenico Spadafora
- Department of Microbiology and Immunology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jonathon P Audia
- Department of Microbiology and Immunology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Dara W Frank
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Sarah Voth
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Monroe, Louisiana, United States
| | - Viktoriya V Pastukh
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jessica Bell
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Linn Ayers
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Dhananjay T Tambe
- Department of Mechanical, Aerospace, and Biomedical Engineering, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Amy R Nelson
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Ron Balczon
- Department of Biochemistry and Molecular Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mike T Lin
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Troy Stevens
- Department of Physiology and Cell Biology, Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
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VPS35 regulates tau phosphorylation and neuropathology in tauopathy. Mol Psychiatry 2021; 26:6992-7005. [PMID: 31289348 PMCID: PMC6949432 DOI: 10.1038/s41380-019-0453-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/12/2019] [Accepted: 04/11/2019] [Indexed: 01/27/2023]
Abstract
The vacuolar protein sorting 35 (VPS35) is a major component of the retromer recognition core complex which regulates intracellular protein sorting and trafficking. Deficiency in VPS35 by altering APP/Aβ metabolism has been linked to late-onset Alzheimer's disease. Here we report that VPS35 is significantly reduced in Progressive Supra-nuclear Palsy and Picks' disease, two distinct primary tauopathies. In vitro studies show that overexpression of VPS35 leads to a reduction of pathological tau in neuronal cells, whereas genetic silencing of VPS35 results in its accumulation. Mechanistically the availability of active cathepsin D mediates the effect of VPS35 on pathological tau accumulation. Moreover, in a relevant transgenic mouse model of tauopathy, down-regulation of VPS35 results in an exacerbation of motor and learning impairments as well as accumulation of pathological tau and loss of synaptic integrity. Taken together, our data identify VPS35 as a novel critical player in tau metabolism and neuropathology, and a new therapeutic target for human tauopathies.
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Bhute S, Sarmah D, Datta A, Rane P, Shard A, Goswami A, Borah A, Kalia K, Dave KR, Bhattacharya P. Molecular Pathogenesis and Interventional Strategies for Alzheimer's Disease: Promises and Pitfalls. ACS Pharmacol Transl Sci 2020; 3:472-488. [PMID: 32566913 DOI: 10.1021/acsptsci.9b00104] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is a debilitating disorder characterized by age-related dementia, which has no effective treatment to date. β-Amyloid depositions and hyperphosphorylated tau proteins are the main pathological hallmarks, along with oxidative stress, N-methyl-d-aspartate (NMDA) receptor-mediated excitotoxicity, and low levels of acetylcholine. Current pharmacotherapy for AD only provides symptomatic relief and limited improvement in cognitive functions. Many molecules have been explored that show promising outcomes in AD therapy and can regulate cellular survival through different pathways. To have a vivid approach to strategize the treatment regimen, AD physiopathology should be better explained considering diverse etiological factors in conjunction with biochemical disturbances. This Review attempts to discuss different disease modification approaches and address the novel therapeutic targets of AD that might pave the way for new drug discovery using the well-defined targets for therapy of the disease.
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Affiliation(s)
- Shashikala Bhute
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Deepaneeta Sarmah
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Aishika Datta
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Pallavi Rane
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Amit Shard
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Avirag Goswami
- Department of Neurology, Albert Einstein Medical Center, Philadelphia, Pennsylvania 19141, United States
| | - Anupom Borah
- Department of Life Science and Bioinformatics, Assam University, Silchar, Assam-788011, India
| | - Kiran Kalia
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
| | - Kunjan R Dave
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136, United States
| | - Pallab Bhattacharya
- Department of Pharmacology and Toxicology,National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar-382355, Gujarat, India
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Gupta MK, Vadde R. In silico identification of natural product inhibitors for γ‐secretase activating protein, a therapeutic target for Alzheimer's disease. J Cell Biochem 2018; 120:10323-10336. [PMID: 30565717 DOI: 10.1002/jcb.28316] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 11/28/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Manoj Kumar Gupta
- Department of Biotechnology & Bioinformatics Yogi Vemana University, Kadapa Andhra Pradesh India
| | - Ramakrishna Vadde
- Department of Biotechnology & Bioinformatics Yogi Vemana University, Kadapa Andhra Pradesh India
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Pein H, Ville A, Pace S, Temml V, Garscha U, Raasch M, Alsabil K, Viault G, Dinh CP, Guilet D, Troisi F, Neukirch K, König S, Bilancia R, Waltenberger B, Stuppner H, Wallert M, Lorkowski S, Weinigel C, Rummler S, Birringer M, Roviezzo F, Sautebin L, Helesbeux JJ, Séraphin D, Mosig AS, Schuster D, Rossi A, Richomme P, Werz O, Koeberle A. Endogenous metabolites of vitamin E limit inflammation by targeting 5-lipoxygenase. Nat Commun 2018; 9:3834. [PMID: 30237488 PMCID: PMC6148290 DOI: 10.1038/s41467-018-06158-5] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 08/22/2018] [Indexed: 12/19/2022] Open
Abstract
Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological role is unknown. Here we show, by library screening of potential human vitamin E metabolites, that long-chain ω-carboxylates are potent allosteric inhibitors of 5-lipoxygenase, a key enzyme in the biosynthesis of chemoattractant and vasoactive leukotrienes. 13-((2R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)-2,6,10-trimethyltridecanoic acid (α-T-13'-COOH) can be synthesized from α-tocopherol in a human liver-on-chip, and is detected in human and mouse plasma at concentrations (8-49 nM) that inhibit 5-lipoxygenase in human leukocytes. α-T-13'-COOH accumulates in immune cells and inflamed murine exudates, selectively inhibits the biosynthesis of 5-lipoxygenase-derived lipid mediators in vitro and in vivo, and efficiently suppresses inflammation and bronchial hyper-reactivity in mouse models of peritonitis and asthma. Together, our data suggest that the immune regulatory and anti-inflammatory functions of α-tocopherol depend on its endogenous metabolite α-T-13'-COOH, potentially through inhibiting 5-lipoxygenase in immune cells.
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Affiliation(s)
- Helmut Pein
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Alexia Ville
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Simona Pace
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Veronika Temml
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Ulrike Garscha
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Martin Raasch
- Institute of Biochemistry II and Center for Sepsis Control and Care, University Hospital Jena, 07743, Jena, Germany
| | - Khaled Alsabil
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Guillaume Viault
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Chau-Phi Dinh
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - David Guilet
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Fabiana Troisi
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Konstantin Neukirch
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Stefanie König
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Rosella Bilancia
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Birgit Waltenberger
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Hermann Stuppner
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Maria Wallert
- Chair of Nutritional Biochemistry and Physiology, Institute of Nutrition, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Stefan Lorkowski
- Chair of Nutritional Biochemistry and Physiology, Institute of Nutrition, Friedrich-Schiller-University Jena, 07743, Jena, Germany.,Competence Cluster of Nutrition and Cardiovascular Health (nutriCARD), Halle, Jena and Leipzig, Jena, 07743, Germany
| | - Christina Weinigel
- Institute of Transfusion Medicine, University Hospital Jena, 07747, Jena, Germany
| | - Silke Rummler
- Institute of Transfusion Medicine, University Hospital Jena, 07747, Jena, Germany
| | - Marc Birringer
- Department of Nutritional, Food and Consumer Sciences, Fulda University of Applied Sciences, 36037, Fulda, Germany
| | - Fiorentina Roviezzo
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Lidia Sautebin
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Jean-Jacques Helesbeux
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Denis Séraphin
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Alexander S Mosig
- Institute of Biochemistry II and Center for Sepsis Control and Care, University Hospital Jena, 07743, Jena, Germany
| | - Daniela Schuster
- Institute of Pharmacy/Pharmaceutical Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria.,Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University Salzburg, 5020, Salzburg, Austria
| | - Antonietta Rossi
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Pascal Richomme
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Oliver Werz
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany.
| | - Andreas Koeberle
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany.
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Perez SE, Nadeem M, Malek-Ahmadi MH, He B, Mufson EJ. Frontal Cortex and Hippocampal γ-Secretase Activating Protein Levels in Prodromal Alzheimer Disease. NEURODEGENER DIS 2017; 17:235-241. [PMID: 28743126 DOI: 10.1159/000477937] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/01/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND β-Amyloid (Aβ) is the product of concerted cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. However, the molecular mechanisms that regulate this process are not well understood. Recently, evidence was reported that γ-secretase activating protein (GSAP, 16 kDa), derived from a larger precursor protein (98 kDa), plays a role in Aβ metabolism through a mechanism involving its interaction with both γ-secretase and APP. However, a detailed evaluation of GSAP protein levels and their association with clinical and neuropathological variables are lacking during the clinical progression of Alzheimer disease (AD). METHODS We quantified levels of the GSAP precursor (98 kDa) and its active form (16 kDa) in the frontal cortex and hippocampus, areas displaying extensive Aβ and neurofibrillary tangle (NFT) pathology, in subjects who came to autopsy with a premortem clinical diagnosis of noncognitive impairment, mild cognitive impairment, mild to moderate AD, and severe AD using Western blotting. RESULTS Analysis found that 98-kDa GSAP levels were increased, while those of 16 kDa were reduced in the frontal cortex of severe-AD subjects. By contrast, GSAP levels remained stable in the hippocampus. Frontal cortex and hippocampal GSAP 98- and 16-kDa levels were not associated with Aβ, NFT, and neuropathological criteria across clinical groups. Interestingly, only neocortical 98-kDa GSAP values showed a significant correlation with the Mini-Mental State Examination and episodic memory scores. CONCLUSIONS These data demonstrate that GSAP proteins are differentially dysregulated in severe AD, but only the full-length form was associated with cognitive test scores in AD.
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Affiliation(s)
- Sylvia E Perez
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
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Chu J, Praticò D. The 5-Lipoxygenase as modulator of Alzheimer's γ-secretase and therapeutic target. Brain Res Bull 2016; 126:207-212. [PMID: 27005438 DOI: 10.1016/j.brainresbull.2016.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
Abstract
Alzheimer's disease (AD) is an age-related, neurodegenerative disorder characterized by cognitive impairment with memory loss, extracellular amyloid beta (Aβ) peptides aggregation, and intracellular hyper-phosphorylated tau neurofibrillary tangles (NFT) accumulation. Although the 5-lipoxygenase (5LO) protein enzyme is well known as an important modulators of oxidation and inflammation, recent work has highlighted the new hypothesis that this pathway may play a direct role in AD pathogenesis. In this review article, we will discuss how the 5LO via the γ-secretase influences Aβ peptides formation, and other molecular pathologies including neuroinflammation, synaptic integrity, and cognitive functions, and provide an assessment of how targeting this protein could lead to novel therapeutics for AD and other related neurodegenerative disorders.
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Affiliation(s)
- Jin Chu
- Department of Pharmacology and Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Domenico Praticò
- Department of Pharmacology and Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, United States.
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The Lipoxygenases: Their Regulation and Implication in Alzheimer's Disease. Neurochem Res 2015; 41:243-57. [PMID: 26677076 PMCID: PMC4773476 DOI: 10.1007/s11064-015-1776-x] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/06/2015] [Accepted: 11/14/2015] [Indexed: 02/03/2023]
Abstract
Inflammatory processes and alterations of lipid metabolism play a crucial role in Alzheimer’s disease (AD) and other neurodegenerative disorders. Polyunsaturated fatty acids (PUFA) metabolism impaired by cyclooxygenases (COX-1, COX-2), which are responsible for formation of several eicosanoids, and by lipoxygenases (LOXs) that catalyze the addition of oxygen to linolenic, arachidonic (AA), and docosahexaenoic acids (DHA) and other PUFA leading to formation of bioactive lipids, significantly affects the course of neurodegenerative diseases. Among several isoforms, 5-LOX and 12/15-LOX are especially important in neuroinflammation/neurodegeneration. These two LOXs are regulated by substrate concentration and availability, and by phosphorylation/dephosphorylation through protein kinases PKA, PKC and MAP-kinases, including ERK1/ERK2 and p38. The protein/protein interaction also is involved in the mechanism of 5-LOX regulation through FLAP protein and coactosin-like protein. Moreover, non-heme iron and calcium ions are potent regulators of LOXs. The enzyme activity significantly depends on the cell redox state and is differently regulated by various signaling pathways. 5-LOX and 12/15-LOX convert linolenic acid, AA, and DHA into several bioactive compounds e.g. hydroperoxyeicosatetraenoic acids (5-HPETE, 12S-HPETE, 15S-HPETE), which are reduced to corresponding HETE compounds. These enzymes synthesize several bioactive lipids, e.g. leucotrienes, lipoxins, hepoxilins and docosahexaenoids. 15-LOX is responsible for DHA metabolism into neuroprotectin D1 (NPD1) with significant antiapoptotic properties which is down-regulated in AD. In this review, the regulation and impact of 5-LOX and 12/15-LOX in the pathomechanism of AD is discussed. Moreover, we describe the role of several products of LOXs, which may have significant pro- or anti-inflammatory activity in AD, and the cytoprotective effects of LOX inhibitors.
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