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Kang Y, Toyoda H, Saito M. Search for unknown neural link between the masticatory and cognitive brain systems to clarify the involvement of its impairment in the pathogenesis of Alzheimer's disease. Front Cell Neurosci 2024; 18:1425645. [PMID: 38994328 PMCID: PMC11236757 DOI: 10.3389/fncel.2024.1425645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Accepted: 06/12/2024] [Indexed: 07/13/2024] Open
Abstract
Brain degenerations in sporadic Alzheimer's disease (AD) are observed earliest in the locus coeruleus (LC), a population of noradrenergic neurons, in which hyperphosphorylated tau protein expression and β-amyloid (Aβ) accumulation begin. Along with this, similar changes occur in the basal forebrain cholinergic neurons, such as the nucleus basalis of Meynert. Neuronal degeneration of the two neuronal nuclei leads to a decrease in neurotrophic factors such as brain-derived neurotrophic factor (BDNF) in the hippocampus and cerebral cortex, which results in the accumulation of Aβ and hyperphosphorylated tau protein and ultimately causes neuronal cell death in those cortices. On the other hand, a large number of epidemiological studies have shown that tooth loss or masticatory dysfunction is a risk factor for dementia including AD, and numerous studies using experimental animals have also shown that masticatory dysfunction causes brain degeneration in the basal forebrain, hippocampus, and cerebral cortex similar to those observed in human AD, and that learning and memory functions are impaired accordingly. However, it remains unclear how masticatory dysfunction can induce such brain degeneration similar to AD, and the neural mechanism linking the trigeminal nervous system responsible for mastication and the cognitive and memory brain system remains unknown. In this review paper, we provide clues to the search for such "missing link" by discussing the embryological, anatomical, and physiological relationship between LC and its laterally adjoining mesencephalic trigeminal nucleus which plays a central role in the masticatory functions.
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Affiliation(s)
- Youngnam Kang
- Department of Behavioral Physiology, Osaka University Graduate School of Human Sciences, Osaka, Japan
| | - Hiroki Toyoda
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Mitsuru Saito
- Department of Oral Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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2
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Hok L, Rimac H, Mavri J, Vianello R. COVID-19 infection and neurodegeneration: Computational evidence for interactions between the SARS-CoV-2 spike protein and monoamine oxidase enzymes. Comput Struct Biotechnol J 2022; 20:1254-1263. [PMID: 35228857 PMCID: PMC8868002 DOI: 10.1016/j.csbj.2022.02.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 12/12/2022] Open
Abstract
Although COVID-19 has been primarily associated with pneumonia, recent data show that its causative agent, the SARS-CoV-2 coronavirus, can infect many vital organs beyond the lungs, including the heart, kidneys and the brain. The literature agrees that COVID-19 is likely to have long-term mental health effects on infected individuals, which signifies a need to understand the role of the virus in the pathophysiology of brain disorders that is currently unknown and widely debated. Our docking and molecular dynamics simulations show that the affinity of the spike protein from the wild type (WT) and the South African B.1.351 (SA) variant towards MAO enzymes is comparable to that for its ACE2 receptor. This allows for the WT/SA⋅⋅⋅MAO complex formation, which changes MAO affinities for their neurotransmitter substrates, thereby impacting their metabolic conversion and misbalancing their levels. Knowing that this fine regulation is strongly linked with the etiology of various brain pathologies, these results are the first to highlight the possibility that the interference with the brain MAO catalytic activity is responsible for the increased neurodegenerative illnesses following a COVID-19 infection, thus placing a neurobiological link between these two conditions in the spotlight. Since the obtained insight suggests that a more contagious SA variant causes even larger disturbances, and with new and more problematic strains likely emerging in the near future, we firmly advise that the presented prospect of the SARS-CoV-2 induced neurological complications should not be ignored, but rather requires further clinical investigations to achieve an early diagnosis and timely therapeutic interventions.
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Affiliation(s)
- Lucija Hok
- Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Hrvoje Rimac
- Department of Medicinal Chemistry, University of Zagreb Faculty of Pharmacy and Biochemistry, Zagreb, Croatia
| | - Janez Mavri
- National Institute of Chemistry, Ljubljana, Slovenia
| | - Robert Vianello
- Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia
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3
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Metabolic Features of Brain Function with Relevance to Clinical Features of Alzheimer and Parkinson Diseases. Molecules 2022; 27:molecules27030951. [PMID: 35164216 PMCID: PMC8839962 DOI: 10.3390/molecules27030951] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 12/04/2022] Open
Abstract
Brain metabolism is comprised in Alzheimer’s disease (AD) and Parkinson’s disease (PD). Since the brain primarily relies on metabolism of glucose, ketone bodies, and amino acids, aspects of these metabolic processes in these disorders—and particularly how these altered metabolic processes are related to oxidative and/or nitrosative stress and the resulting damaged targets—are reviewed in this paper. Greater understanding of the decreased functions in brain metabolism in AD and PD is posited to lead to potentially important therapeutic strategies to address both of these disorders, which cause relatively long-lasting decreased quality of life in patients.
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Abstract
We have structure, a wealth of kinetic data, thousands of chemical ligands and clinical information for the effects of a range of drugs on monoamine oxidase activity in vivo. We have comparative information from various species and mutations on kinetics and effects of inhibition. Nevertheless, there are what seem like simple questions still to be answered. This article presents a brief summary of existing experimental evidence the background and poses questions that remain intriguing for chemists and biochemists researching the chemical enzymology of and drug design for monoamine oxidases (FAD-containing EC 4.1.3.4).
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5
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Quartey MO, Nyarko JNK, Maley JM, Barnes JR, Bolanos MAC, Heistad RM, Knudsen KJ, Pennington PR, Buttigieg J, De Carvalho CE, Leary SC, Parsons MP, Mousseau DD. The Aβ(1-38) peptide is a negative regulator of the Aβ(1-42) peptide implicated in Alzheimer disease progression. Sci Rep 2021; 11:431. [PMID: 33432101 PMCID: PMC7801637 DOI: 10.1038/s41598-020-80164-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 12/17/2020] [Indexed: 12/14/2022] Open
Abstract
The pool of β-Amyloid (Aβ) length variants detected in preclinical and clinical Alzheimer disease (AD) samples suggests a diversity of roles for Aβ peptides. We examined how a naturally occurring variant, e.g. Aβ(1-38), interacts with the AD-related variant, Aβ(1-42), and the predominant physiological variant, Aβ(1-40). Atomic force microscopy, Thioflavin T fluorescence, circular dichroism, dynamic light scattering, and surface plasmon resonance reveal that Aβ(1-38) interacts differently with Aβ(1-40) and Aβ(1-42) and, in general, Aβ(1-38) interferes with the conversion of Aβ(1-42) to a β-sheet-rich aggregate. Functionally, Aβ(1-38) reverses the negative impact of Aβ(1-42) on long-term potentiation in acute hippocampal slices and on membrane conductance in primary neurons, and mitigates an Aβ(1-42) phenotype in Caenorhabditis elegans. Aβ(1-38) also reverses any loss of MTT conversion induced by Aβ(1-40) and Aβ(1-42) in HT-22 hippocampal neurons and APOE ε4-positive human fibroblasts, although the combination of Aβ(1-38) and Aβ(1-42) inhibits MTT conversion in APOE ε4-negative fibroblasts. A greater ratio of soluble Aβ(1-42)/Aβ(1-38) [and Aβ(1-42)/Aβ(1-40)] in autopsied brain extracts correlates with an earlier age-at-death in males (but not females) with a diagnosis of AD. These results suggest that Aβ(1-38) is capable of physically counteracting, potentially in a sex-dependent manner, the neuropathological effects of the AD-relevant Aβ(1-42).
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Affiliation(s)
- Maa O Quartey
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Jennifer N K Nyarko
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Jason M Maley
- Saskatchewan Structural Sciences Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jocelyn R Barnes
- Division of BioMedical Sciences (Neurosciences), Memorial University of Newfoundland, St. John's, NL, Canada
| | | | - Ryan M Heistad
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Kaeli J Knudsen
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Paul R Pennington
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada
| | - Josef Buttigieg
- Department of Biology, University of Regina, Regina, SK, Canada
| | | | - Scot C Leary
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Matthew P Parsons
- Division of BioMedical Sciences (Neurosciences), Memorial University of Newfoundland, St. John's, NL, Canada
| | - Darrell D Mousseau
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, GB41 HSB, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada.
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Wong KY, Roy J, Fung ML, Heng BC, Zhang C, Lim LW. Relationships between Mitochondrial Dysfunction and Neurotransmission Failure in Alzheimer's Disease. Aging Dis 2020; 11:1291-1316. [PMID: 33014538 PMCID: PMC7505271 DOI: 10.14336/ad.2019.1125] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022] Open
Abstract
Besides extracellular deposition of amyloid beta and formation of phosphorylated tau in the brains of patients with Alzheimer's disease (AD), the pathogenesis of AD is also thought to involve mitochondrial dysfunctions and altered neurotransmission systems. However, none of these components can describe the diverse cognitive, behavioural, and psychiatric symptoms of AD without the pathologies interacting with one another. The purpose of this review is to understand the relationships between mitochondrial and neurotransmission dysfunctions in terms of (1) how mitochondrial alterations affect cholinergic and monoaminergic systems via disruption of energy metabolism, oxidative stress, and apoptosis; and (2) how different neurotransmission systems drive mitochondrial dysfunction via increasing amyloid beta internalisation, oxidative stress, disruption of mitochondrial permeabilisation, and mitochondrial trafficking. All these interactions are separately discussed in terms of neurotransmission systems. The association of mitochondrial dysfunctions with alterations in dopamine, norepinephrine, and histamine is the prospective goal in this research field. By unfolding the complex interactions surrounding mitochondrial dysfunction in AD, we can better develop potential treatments to delay, prevent, or cure this devastating disease.
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Affiliation(s)
- Kan Yin Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Jaydeep Roy
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Man Lung Fung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Boon Chin Heng
- Peking University School of Stomatology, Beijing, China.
| | - Chengfei Zhang
- Endodontology, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
| | - Lee Wei Lim
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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Propargylamine-derived multi-target directed ligands for Alzheimer's disease therapy. Bioorg Med Chem Lett 2019; 30:126880. [PMID: 31864798 DOI: 10.1016/j.bmcl.2019.126880] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/25/2019] [Accepted: 11/30/2019] [Indexed: 12/22/2022]
Abstract
Current options for the treatment of Alzheimeŕs disease have been restricted to prescription of acetylcholinesterase inhibitors or N-methyl-d-aspartate receptor antagonist, memantine. Propargylamine-derived multi-target directed ligands, such as ladostigil, M30, ASS234 and contilisant, involve different pathways. Apart from acting as inhibitors of both cholinesterases and monoamine oxidases, they show improvement of cognitive impairment, antioxidant activities, enhancement of iron-chelating activities, protect against tau hyperphosphorylation, block metal-associated oxidative stress, regulate APP and Aβ expression processing by the non-amyloidogenic α-secretase pathway, suppress mitochondrial permeability transition pore opening, and coordinate protein kinase C signaling and Bcl-2 family proteins. Other hybrid propargylamine derivatives are also reported.
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Di Paolo ML, Cervelli M, Mariottini P, Leonetti A, Polticelli F, Rosini M, Milelli A, Basagni F, Venerando R, Agostinelli E, Minarini A. Exploring the activity of polyamine analogues on polyamine and spermine oxidase: methoctramine, a potent and selective inhibitor of polyamine oxidase. J Enzyme Inhib Med Chem 2019; 34:740-752. [PMID: 30829081 PMCID: PMC6407594 DOI: 10.1080/14756366.2019.1584620] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/06/2019] [Accepted: 02/14/2019] [Indexed: 01/16/2023] Open
Abstract
Fourteen polyamine analogues, asymmetric or symmetric substituted spermine (1-9) or methoctramine (10-14) analogues, were evaluated as potential inhibitors or substrates of two enzymes of the polyamine catabolic pathway, spermine oxidase (SMOX) and acetylpolyamine oxidase (PAOX). Compound 2 turned out to be the best substrate for PAOX, having the highest affinity and catalytic efficiency with respect to its physiological substrates. Methoctramine (10), a well-known muscarinic M2 receptor antagonist, emerged as the most potent competitive PAOX inhibitor known so far (Ki = 10 nM), endowed with very good selectivity compared with SMOX (Ki=1.2 μM vs SMOX). The efficacy of methoctramine in inhibiting PAOX activity was confirmed in the HT22 cell line. Methoctramine is a very promising tool in the design of drugs targeting the polyamine catabolism pathway, both to understand the physio-pathological role of PAOX vs SMOX and for pharmacological applications, being the polyamine pathway involved in various pathologies.
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Affiliation(s)
| | | | | | | | - Fabio Polticelli
- Department of Sciences, University of Roma Tre, Roma, Italy
- Roma Tre Section, National Institute of Nuclear Physics, Roma, Italy
| | - Michela Rosini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Andrea Milelli
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, Rimini, Italy
| | - Filippo Basagni
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Rina Venerando
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Enzo Agostinelli
- Department of Biochemical Science "A. Rossi Fanelli", University of Rome "La Sapienza", Rome, Italy
- International Polyamines Foundation – ONLUS –Via del Forte Tiburtino 98, Rome, Italy
| | - Anna Minarini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
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9
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Gwynne WD, Shakeel MS, Wu J, Hallett RM, Girgis-Gabardo A, Dvorkin-Gheva A, Hassell JA. Monoamine oxidase-A activity is required for clonal tumorsphere formation by human breast tumor cells. Cell Mol Biol Lett 2019; 24:59. [PMID: 31754354 PMCID: PMC6852929 DOI: 10.1186/s11658-019-0183-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/01/2019] [Indexed: 12/15/2022] Open
Abstract
Background Breast tumor growth and recurrence are driven by an infrequent population of breast tumor-initiating cells (BTIC). We and others have reported that the frequency of BTIC is orders of magnitude higher when breast tumor cells are propagated in vitro as clonal spheres, termed tumorspheres, by comparison to adherent cells. We exploited the latter to screen > 35,000 small molecules to identify agents capable of targeting BTIC. We unexpectedly discovered that selective antagonists of serotonin signaling were among the hit compounds. To better understand the relationship between serotonin and BTIC we expanded our analysis to include monoamine oxidase-A (MAO-A), an enzyme that metabolizes serotonin. Methods We used the Nanostring technology and Western blotting to determine whether MAO-A is expressed in human breast tumor cell lines cultured as tumorspheres by comparison to those grown as adherent cells. We then determined whether MAO-A activity is required for tumorsphere formation, a surrogate in vitro assay for BTIC, by assessing whether selective MAO-A inhibitors affect the frequency of tumorsphere-forming cells. To learn whether MAO-A expression in breast tumor cells is associated with other reported properties of BTIC such as anticancer drug resistance or breast tumor recurrence, we performed differential gene expression analyses using publicly available transcriptomic datasets. Results Tumorspheres derived from human breast tumor cell lines representative of every breast cancer clinical subtype displayed increased expression of MAO-A transcripts and protein by comparison to adherent cells. Surprisingly, inhibition of MAO-A activity with selective inhibitors reduced the frequency of tumorsphere-forming cells. We also found that increased MAO-A expression is a common feature of human breast tumor cell lines that have acquired anticancer drug resistance and is associated with poor recurrence-free survival (RFS) in patients that experienced high-grade, ER-negative (ER−) breast tumors. Conclusions Our data suggests that MAO-A activity is required for tumorsphere formation and that its expression in breast tumor cells is associated with BTIC-related properties. The discovery that a selective MAO-A inhibitor targets tumorsphere-forming cells with potencies in the nanomolar range provides the first evidence of this agent’s anticancer property. These data warrant further investigation of the link between MAO-A and BTIC.
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Affiliation(s)
- William D Gwynne
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
| | - Mirza S Shakeel
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
| | - Jianhan Wu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
| | - Robin M Hallett
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
| | - Adele Girgis-Gabardo
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
| | - Anna Dvorkin-Gheva
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
| | - John A Hassell
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario Canada
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Lacidipine attenuates reserpine-induced depression-like behavior and oxido-nitrosative stress in mice. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1265-1275. [DOI: 10.1007/s00210-019-01667-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 05/16/2019] [Indexed: 10/26/2022]
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11
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Nyarko JNK, Quartey MO, Baker GB, Mousseau DD. Can Animal Models Inform on the Relationship between Depression and Alzheimer Disease? CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2019; 64:18-29. [PMID: 29685068 PMCID: PMC6364140 DOI: 10.1177/0706743718772514] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The focus on the β-amyloid (Aβ) peptide in clinical Alzheimer disease (AD) as well as in animal models of AD has perhaps biased our understanding of what contributes to the heterogeneity in disease onset and progression. Part of this heterogeneity could reflect the various neuropsychiatric risk factors that present with common symptomatology and can predispose the brain to AD-like changes. One such risk factor is depression. Animal models, particularly mouse models carrying variants of AD-related gene(s), many of which lead to an accumulation of Aβ, suggest that a fundamental shift in depression-related monoaminergic systems (including serotonin and noradrenaline) is a strong indicator of the altered cellular function associated with the earlier(est) stages of AD-related pathology. These changes in monoaminergic neurochemistry could provide for relevant targets for intervention in clinical AD and/or could support a polypharmacy strategy, which might include the targeting of Aβ, in vulnerable populations. Future studies must also include female mice as well as male mice in animal model studies on the relationship between depression and AD.
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Affiliation(s)
- Jennifer N K Nyarko
- 1 Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Maa O Quartey
- 1 Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Glen B Baker
- 2 Department of Psychiatry, Neuroscience and Mental Health Institute, Neurochemical Research Unit, University of Alberta, Edmonton, Alberta, Canada
| | - Darrell D Mousseau
- 1 Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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12
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Quartey MO, Nyarko JNK, Pennington PR, Heistad RM, Klassen PC, Baker GB, Mousseau DD. Alzheimer Disease and Selected Risk Factors Disrupt a Co-regulation of Monoamine Oxidase-A/B in the Hippocampus, but Not in the Cortex. Front Neurosci 2018; 12:419. [PMID: 29997470 PMCID: PMC6029266 DOI: 10.3389/fnins.2018.00419] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/01/2018] [Indexed: 01/09/2023] Open
Abstract
Monoamine oxidase-A (MAO-A) and MAO-B have both been implicated in the pathology of Alzheimer disease (AD). We examined 60 autopsied control and AD donor brain samples to determine how well MAO function aligned with two major risk factors for AD, namely sex and APOE ε4 status. MAO-A activity was increased in AD cortical, but not hippocampal, samples. In contrast, MAO-B activity was increased in both regions (with a strong input from female donors) whether sample means were compared based on: (a) diagnosis alone; (b) diagnosis-by-APOE ε4 status (i.e., carriers vs. non-carriers of the ε4 allele); or (c) APOE ε4 status alone (i.e., ignoring ‘diagnosis’ as a variable). Sample means strictly based on the donor’s sex did not reveal any difference in either MAO-A or MAO-B activity. Unexpectedly, we found that cortical MAO-A and MAO-B activities were highly correlated in both males and females (if focussing strictly on the donor’s sex), while in the hippocampus, any correlation was lost in female samples. Stratifying for sex-by-APOE ε4 status revealed a strong correlation between cortical MAO-A and MAO-B activities in both non-carriers and carriers of the allele, but any correlation in hippocampal samples was lost in carriers of the allele. A diagnosis of AD disrupted the correlation between MAO-A and MAO-B activities in the hippocampus, but not the cortex. We observed a novel region-dependent co-regulation of MAO-A and MAO-B mRNAs (but not proteins), while a lack of correlation between MAO activities and the respective proteins corroborated previous reports. Overexpression of human APOE4 increased MAO activity (but not mRNA/protein) in C6 and in HT-22 cell cultures. We identified a novel co-regulation of MAO-A and MAO-B activities that is spared from any influence of risk factors for AD or AD itself in the cortex, but vulnerable to these same factors in the hippocampus. Sex- and region-dependent abilities to buffer influences on brain MAO activities could have significant bearing on ambiguous outcomes when monoaminergic systems are targeted in clinical populations.
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Affiliation(s)
- Maa O Quartey
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jennifer N K Nyarko
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Paul R Pennington
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ryan M Heistad
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Paula C Klassen
- The Pharmacology-Physiology Honours Program, University of Saskatchewan, Saskatoon, SK, Canada
| | - Glen B Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Darrell D Mousseau
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada.,The Pharmacology-Physiology Honours Program, University of Saskatchewan, Saskatoon, SK, Canada
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13
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Cobley JN, Fiorello ML, Bailey DM. 13 reasons why the brain is susceptible to oxidative stress. Redox Biol 2018; 15:490-503. [PMID: 29413961 PMCID: PMC5881419 DOI: 10.1016/j.redox.2018.01.008] [Citation(s) in RCA: 668] [Impact Index Per Article: 111.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 12/12/2022] Open
Abstract
The human brain consumes 20% of the total basal oxygen (O2) budget to support ATP intensive neuronal activity. Without sufficient O2 to support ATP demands, neuronal activity fails, such that, even transient ischemia is neurodegenerative. While the essentiality of O2 to brain function is clear, how oxidative stress causes neurodegeneration is ambiguous. Ambiguity exists because many of the reasons why the brain is susceptible to oxidative stress remain obscure. Many are erroneously understood as the deleterious result of adventitious O2 derived free radical and non-radical species generation. To understand how many reasons underpin oxidative stress, one must first re-cast free radical and non-radical species in a positive light because their deliberate generation enables the brain to achieve critical functions (e.g. synaptic plasticity) through redox signalling (i.e. positive functionality). Using free radicals and non-radical derivatives to signal sensitises the brain to oxidative stress when redox signalling goes awry (i.e. negative functionality). To advance mechanistic understanding, we rationalise 13 reasons why the brain is susceptible to oxidative stress. Key reasons include inter alia unsaturated lipid enrichment, mitochondria, calcium, glutamate, modest antioxidant defence, redox active transition metals and neurotransmitter auto-oxidation. We review RNA oxidation as an underappreciated cause of oxidative stress. The complex interplay between each reason dictates neuronal susceptibility to oxidative stress in a dynamic context and neural identity dependent manner. Our discourse sets the stage for investigators to interrogate the biochemical basis of oxidative stress in the brain in health and disease.
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Affiliation(s)
- James Nathan Cobley
- Free Radical Laboratory, Departments of Diabetes and Cardiovascular Sciences, Centre for Health Sciences, University of the Highlands and Islands, Inverness IV2 3HJ, UK.
| | - Maria Luisa Fiorello
- Free Radical Laboratory, Departments of Diabetes and Cardiovascular Sciences, Centre for Health Sciences, University of the Highlands and Islands, Inverness IV2 3HJ, UK
| | - Damian Miles Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, CF37 4AT, UK
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14
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Naoi M, Maruyama W, Shamoto-Nagai M. Type A and B monoamine oxidases distinctly modulate signal transduction pathway and gene expression to regulate brain function and survival of neurons. J Neural Transm (Vienna) 2017; 125:1635-1650. [DOI: 10.1007/s00702-017-1832-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 12/18/2017] [Indexed: 02/01/2023]
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MacKenzie EM, Song MS, Dursun SM, Tomlinson S, Todd KG, Baker GB. Phenelzine: An Old Drug That May Hold Clues to The Development of New Neuroprotective Agents. ACTA ACUST UNITED AC 2016. [DOI: 10.1080/10177833.2010.11790656] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Erin M. MacKenzie
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Mee-Sook Song
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Serdar M. Dursun
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Sara Tomlinson
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Kathryn G. Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Glen B. Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
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Naoi M, Riederer P, Maruyama W. Modulation of monoamine oxidase (MAO) expression in neuropsychiatric disorders: genetic and environmental factors involved in type A MAO expression. J Neural Transm (Vienna) 2015; 123:91-106. [PMID: 25604428 DOI: 10.1007/s00702-014-1362-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 12/27/2014] [Indexed: 12/18/2022]
Abstract
Monoamine oxidase types A and B (MAO-A, MAO-B) regulate the levels of monoamine neurotransmitters in the brain, and their dysfunction may be involved in the pathogenesis and influence the clinical phenotypes of neuropsychiatric disorders. Reversible MAO-A inhibitors, such as moclobemide and befloxatone, are currently employed in the treatment of emotional disorders by inhibiting the enzymatic degradation of dopamine, serotonin and norepinephrine in the central nervous system (CNS). It has been suggested that the irreversible MAO-B inhibitors selegiline and rasagiline exert a neuroprotective effect in Parkinson's and Alzheimer's diseases. This effect, however, is not related to their inhibition of MAO activity; in animal and cellular models, selegiline and rasagiline protect neuronal cells through their anti-apoptotic activity and induction of pro-survival genes. There is increasing evidence that MAO-A activity, but not that of MAO-B, is implicated in the pathophysiology of neurodegenerative disorders, but also in gene induction by MAO-B inhibitors; on the other hand, selegiline and rasagiline increase MAO-A mRNA, protein, and enzyme activity levels. Taken together, these results suggest that each MAO subtype exerts effects that modulate the expression and activity of the other isoenzyme. The roles of MAO-A and -B in the CNS should therefore be re-evaluated with respect to the "type-specificity" of their inhibitors, which may not be unconditional during chronic treatment. Mao-a expression, in particular, may be implicated in pathogenesis and phenotypes in neuropsychiatric disorders. MAO-A expression is modified by mao polymorphisms affecting its transcriptional efficiency, as well as by mutations and polymorphism of parkin, Sirt1, FOXO, microRNA, presenilin-1, and other regulatory proteins. In addition, childhood maltreatment has been shown to have an impact upon adolescent social behavior in children with mao-a polymorphisms of low transcriptional activity. Low MAO-A activity may increase the levels of serotonin and norepinephrine, resulting in disturbed neurotransmitter system development and behavior. This review discusses genetic and environmental factors involved in the regulation of MAO-A expression, in the contexts of neuropsychiatric function and of the regulation of neuronal survival and death.
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Affiliation(s)
- Makoto Naoi
- Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin, Aichi, 470-0195, Japan.
| | - Peter Riederer
- Clinical Neurochemistry, National Parkinson's Foundation Centre of Excellence Laboratories, Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital Würzburg, Würzburg, Germany
| | - Wakako Maruyama
- Department of Cognitive Brain Science, National Research Center for Geriatrics and Gerontology, Obu, Aichi, Japan
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Satram-Maharaj T, Nyarko JN, Kuski K, Fehr K, Pennington PR, Truitt L, Freywald A, Lukong KE, Anderson DH, Mousseau DD. The monoamine oxidase-A inhibitor clorgyline promotes a mesenchymal-to-epithelial transition in the MDA-MB-231 breast cancer cell line. Cell Signal 2014; 26:2621-32. [DOI: 10.1016/j.cellsig.2014.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Revised: 07/29/2014] [Accepted: 08/15/2014] [Indexed: 01/15/2023]
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18
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The protective role of Bax inhibitor-1 against chronic mild stress through the inhibition of monoamine oxidase A. Sci Rep 2013; 3:3398. [PMID: 24292328 PMCID: PMC3844965 DOI: 10.1038/srep03398] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/15/2013] [Indexed: 11/08/2022] Open
Abstract
The anti-apoptotic protein Bax inhibitor-1 (BI-1) is a regulator of apoptosis linked to endoplasmic reticulum (ER) stress. It has been hypothesized that BI-1 protects against neuron degenerative diseases. In this study, BI-1⁻/⁻ mice showed increased vulnerability to chronic mild stress accompanied by alterations in the size and morphology of the hippocampi, enhanced ROS accumulation and an ER stress response compared with BI-1⁺/⁺ mice. BI-1⁻/⁻ mice exposed to chronic mild stress showed significant activation of monoamine oxidase A (MAO-A), but not MAO-B, compared with BI-1⁺/⁺ mice. To examine the involvement of BI-1 in the Ca²⁺-sensitive MAO activity, thapsigargin-induced Ca²⁺ release and MAO activity were analyzed in neuronal cells overexpressing BI-1. The in vitro study showed that BI-1 regulates Ca²⁺ release and related MAO-A activity. This study indicates an endogenous protective role of BI-1 under conditions of chronic mild stress that is primarily mediated through Ca²⁺-associated MAO-A regulation.
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Abstract
Monoamine oxidase inhibitors have been available for more than 50 years, initially developed as antidepressants but currently used in a variety of psychiatric and neurological conditions. There has been a recent surge of interest in monoamine oxidase inhibitors because of their reported neuroprotective and/or neurorescue properties. Interestingly, it seems that often these properties are independent of their ability to inhibit monoamine oxidase. This review article presents an overview of the neuroprotective/neurorescue properties of these multifaceted drugs and focuses on phenelzine, (-)-deprenyl, rasagiline, ladostigil, tranylcypromine, moclobemide, and clorgyline and their possible neuroprotective mechanisms.
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20
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Aspartic acid substitutions in monoamine oxidase-A reveal both catalytic-dependent and -independent influences on cell viability and proliferation. J Neural Transm (Vienna) 2012; 119:1285-94. [DOI: 10.1007/s00702-012-0779-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 02/16/2012] [Indexed: 12/17/2022]
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21
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A review on coumarins as acetylcholinesterase inhibitors for Alzheimer's disease. Bioorg Med Chem 2011; 20:1175-80. [PMID: 22257528 DOI: 10.1016/j.bmc.2011.12.042] [Citation(s) in RCA: 345] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 12/18/2011] [Accepted: 12/19/2011] [Indexed: 11/21/2022]
Abstract
Acetylcholinesterase (AChE) enzyme inhibition is an important target for the management of Alzheimer disease (AD) and AChE inhibitors are the main stay drugs for its management. Coumarins are the phytochemicals with wide range of biological activities including AChE inhibition. The scientists have attempted to explore the coumarin template for synthesizing novel AChE inhibitors with additional pharmacological activities including decrease in beta-amyloid (Aβ) deposition and beta-secretase inhibition that are also important for AD management. Most of the designed schemes have involved incorporation of a catalytic site interacting moiety at 3- and 4-positions of the coumarin ring. The present review describes these differently synthesized coumarin derivatives as AChE inhibitors for management of AD.
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22
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Effect of cerebrolysin on the levels of glutathione and 5-HT in different regions of rat brain in presence of dantrolene. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.biomag.2011.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Alzheimer disease-related presenilin-1 variants exert distinct effects on monoamine oxidase-A activity in vitro. J Neural Transm (Vienna) 2011; 118:987-95. [PMID: 21373759 DOI: 10.1007/s00702-011-0616-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 02/17/2011] [Indexed: 10/18/2022]
Abstract
Monoamine oxidase-A (MAO-A) has been associated with both depression and Alzheimer disease (AD). Recently, carriers of AD-related presenilin-1 (PS-1) alleles have been found to be at higher risk for developing clinical depression. We chose to examine whether PS-1 could influence MAO-A function in vitro. Overexpression of selected AD-related PS-1 variants (wildtype, Y115H, ΔEx9 and M146V) in mouse hippocampal HT-22 cells affects MAO-A catalytic activity in a variant-specific manner. The ability of the PS-1 substrate-competitor DAPT to induce MAO-A activity in cells expressing either PS-1 wildtype or PS-1(M146V) suggests the potential for a direct influence of PS-1 on MAO-A function. In support of this, we were able to co-immunoprecipitate MAO-A with FLAG-tagged PS-1 wildtype and M146V proteins. This potential for a direct protein-protein interaction between PS-1 and MAO-A is not specific for HT-22 cells as we were also able to co-immunoprecipitate MAO-A with FLAG-PS-1 variants in N2a mouse neuroblastoma cells and in HEK293 human embryonic kidney cells. Finally, we demonstrate that the two PS-1 variants reported to be associated with an increased incidence of clinical depression [e.g., A431E and L235V] both induce MAO-A activity in HT-22 cells. A direct influence of PS-1 variants on MAO-A function could provide an explanation for the changes in monoaminergic tone observed in several neurodegenerative processes including AD. The ability to induce MAO-A catalytic activity with a PS-1/γ-secretase inhibitor should also be considered when designing secretase inhibitor-based therapeutics.
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Vadapalli S, Katta S, Sastry BKS, Nallari P. MAO-A promoter polymorphism and idiopathic pulmonary arterial hypertension. J Genet 2010. [DOI: 10.1007/s12041-011-0008-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Adam-Vizi V, Starkov AA. Calcium and mitochondrial reactive oxygen species generation: how to read the facts. J Alzheimers Dis 2010; 20 Suppl 2:S413-26. [PMID: 20421693 DOI: 10.3233/jad-2010-100465] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A number of recent discoveries indicate that abnormal Ca2+ signaling, oxidative stress, and mitochondrial dysfunction are involved in the neuronal damage in Alzheimer's disease. However, the literature on the interactions between these factors is controversial especially in the interpretation of the cause-effect relationship between mitochondrial damage induced by Ca2+ overload and the production of reactive oxygen species (ROS). In this review, we survey the experimental observations on the Ca2+-induced mitochondrial ROS production, explain the sources of controversy in interpreting these results, and discuss the different molecular mechanisms underlying the effect of Ca2+ on the ROS emission by brain mitochondria.
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Affiliation(s)
- Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group of Hungarian Academy of Sciences, Budapest, Hungary.
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26
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Halhali A, Figueras AG, Díaz L, Avila E, Barrera D, Hernández G, Larrea F. Effects of calcitriol on calbindins gene expression and lipid peroxidation in human placenta. J Steroid Biochem Mol Biol 2010; 121:448-51. [PMID: 20214988 DOI: 10.1016/j.jsbmb.2010.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 02/11/2010] [Accepted: 03/01/2010] [Indexed: 11/30/2022]
Abstract
Pregnancy is associated with increased maternal calcitriol levels and placenta is an extrarenal source of this hormone. Calbindin-D9k and calbindin-D28k are vitamin D-dependent. Since calbindin-D28k has been considered as an antioxidant factor, the aim of the present work was to investigate the effects of calcitriol on calbindins gene expression and lipid peroxidation in cultured syncytiotrophoblast cells obtained from healthy human placentas. Gene expression of calbindins was evaluated using RT and real-time PCR techniques. Malondialdehyde (MDA) levels were used as lipid peroxidation marker. The results of the present study showed that cultured syncytiotrophoblast cells expressed the mRNA of calbindin-D9k and calbindin-D28k. In addition, calcitriol stimulated gene expression of both calbindins in a dose-dependent manner. Placental MDA levels were not significantly different at physiological concentrations of calcitriol (10(-11) M and 10(-9) M). However, the use of calcitriol at 10(-7) M resulted in significantly higher MDA levels (P<0.05). In conclusion, the results showed that cultured syncytiotrophoblast cells expressed calbindin-D9k and calbindin-D28k genes, which were stimulated by calcitriol. In addition, the results suggest that calcitriol may be considered as pro-oxidant when used at pharmacological doses.
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Affiliation(s)
- Ali Halhali
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan 14000, México D.F., Mexico
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27
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Ash ES, Alavijeh MS, Palmer AM, Mitchelmore C, Howlett DR, Francis PT, Broadstock M, Richardson JC. Neurochemical changes in a double transgenic mouse model of Alzheimer's disease fed a pro-oxidant diet. Neurochem Int 2010; 57:504-11. [PMID: 20600435 DOI: 10.1016/j.neuint.2010.06.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 06/23/2010] [Accepted: 06/24/2010] [Indexed: 01/18/2023]
Abstract
Oxidative stress is implicated in the pathogenesis of Alzheimer's disease (AD) causing neurodegeneration and decreased monoamine neurotransmitters. We investigated the effect of administration of a pro-oxidant diet on the levels of monoamines and metabolites in the brains of wildtype and transgenic mice expressing mutant APP and PS-1 (TASTPM mice). Three-month-old TASTPM and wildtype (C57BL6/J) mice were fed either normal or pro-oxidant diet for 3 months. The neocortex, cerebellum, hippocampus and striatum were assayed for their monoamine and monoamine metabolite content using HPLC with electrochemical detection. Striatal tyrosine hydroxylase (TOH) levels were analysed by Western blotting. In the striatum, female TASTPM mice had higher levels of DOPAC and male TASTPM mice had higher levels of 5-HIAA compared to wildtype mice. Administration of pro-oxidant diet increased striatal MHPG, turnover of NA and 5-HT levels in female TASTPM mice compared to TASTPM mice fed control diet. The pro-oxidant diet also decreased DOPAC levels in female TASTPM mice compared to those fed control diet. Striatal TOH did not depend on diet, gender or genotype. In the neocortex, the TASTPM genotype increased levels of 5-HIAA in male mice fed control diet compared to wildtype mice. In the cerebellum, the TASTPM genotype led to decreased levels of HVA (male mice only) and also decreased turnover of DA (female mice only) compared to wildtype mice. These data suggest a sparing of monoaminergic neurones in the cortex, striatum and hippocampus of TASTPM mice fed pro-oxidant diet and could be indicative of increased activity in corticostriatal circuits. The decreased cerebellar levels of HVA and turnover of DA in TASTPM mice hint at possible axonal degeneration within this subregion.
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28
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Abstract
AbstractMitochondrial enzyme monoamine oxidase A (MAO-A) generates hydrogen peroxide (H2O2) and is up-regulated by Ca2+ and presumably by ammonia. We hypothesized that MAO-A may be under the control of NMDA receptors in hyperammonemia. In this work, the in vivo effects of single dosing with ammonia and NMDA receptor antagonist MK-801 and the in vitro effect of Ca2+ on MAO-A activity in isolated rat brain mitochondria were studied employing enzymatic procedure. Intraperitoneal injection of rats with ammonia led to an increase in MAO-A activity in mitochondria indicating excessive H2O2 generation. Calcium added to isolated mitochondria stimulated MAO-A activity by as much as 84%. MK-801 prevented the in vivo effect of ammonia, implying that MAO-A activation in hyperammonemia is mediated by NMDA receptors. These data support the conclusion that brain mitochondrial MAO-A is regulated by the function of NMDA receptors. The enzyme can contribute to the oxidative stress associated with hyperammonemic conditions such as encephalopathy and Alzheimer’s disease. The attenuation of the oxidative stress highlights MAO-A inactivation and NMDA receptor antagonists as sources of novel avenues in the treatment of mental disorders.
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29
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Barhwal K, Hota SK, Baitharu I, Prasad D, Singh SB, Ilavazhagan G. Isradipine antagonizes hypobaric hypoxia induced CA1 damage and memory impairment: Complementary roles of L-type calcium channel and NMDA receptors. Neurobiol Dis 2009; 34:230-44. [PMID: 19385055 DOI: 10.1016/j.nbd.2009.01.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Hypobaric hypoxia leads to cognitive dysfunctions due to increase in intracellular calcium through ion channels. The purpose of this study was to examine the temporal contribution of L-type calcium channels and N-methyl-D-aspartate receptors (NMDARs) in mediating neuronal death in male Sprague Dawley rats exposed to hypobaric hypoxia simulating an altitude of 25,000 ft for different durations. Decreasing exogenous calcium loads by blocking voltage-gated calcium influx with isradipine (2.5 mg kg(-1)), and its efficacy in providing neuroprotection and preventing memory impairment following hypoxic exposure was also investigated. Effect of isradipine on calcium-dependent enzymes mediating oxidative stress and apoptotic cell death was also studied. Blocking of L-type calcium channels with isradipine reduced hypoxia-induced activation of calcium dependent xanthine oxidases, monoamine oxidases, cytosolic phospholipase A(2) and cycloxygenases (COX-2) along with concomitant decrease in free radical generation and cytochrome c release. Increased expression of calpain and caspase 3 was also observed following exposure to hypobaric hypoxia along with augmented neurodegeneration and memory impairment which was adequately prevented by isradipine administration. Administration of isradipine during hypoxic exposure protected the hippocampal neurons following 3 and 7 days of exposure to hypobaric hypoxia along with improvement in spatial memory.
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Affiliation(s)
- Kalpana Barhwal
- Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Ministry of Defence, Timarpur, Delhi, India
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Cao X, Rui L, Pennington PR, Chlan-Fourney J, Jiang Z, Wei Z, Li XM, Edmondson DE, Mousseau DD. Serine 209 resides within a putative p38(MAPK) consensus motif and regulates monoamine oxidase-A activity. J Neurochem 2009; 111:101-10. [PMID: 19650872 DOI: 10.1111/j.1471-4159.2009.06300.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The p38 mitogen-activated protein kinase (MAPK) cascade as well as the enzyme monoamine oxidase-A (MAO-A) have both been associated with oxidative stress. We observed that the specific inhibition of the p38(MAPK) protein [using either a chemical inhibitor or a dominant-negative p38(MAPK) clone] selectively induces MAO-A activity and MAO-A-sensitive toxicity in several neuronal cell lines, including primary cortical neurons. Over-expression of a constitutively active p38(MAPK) results in the phosphorylation of the MAO-A protein and inhibition of MAO-A activity. The MAO-A(Ser209Glu) phosphomimic - bearing a targeted substitution within a putative p38(MAPK) consensus motif - is neither active nor neurotoxic. In contrast, the MAO-A(Ser209Ala) variant (mimics dephosphorylation) does not associate with p38(MAPK), and is both very active and very toxic. Substitution of the homologous serine in the MAO-B isoform, i.e. Ser200, with either Glu or Ala does not affect the catalytic activity of the corresponding over-expressed proteins. These combined in vitro data strongly suggest a direct p38(MAPK)-dependent inhibition of MAO-A function. Based on published observations, this endogenous means of selectively regulating MAO-A function could provide for an adaptive response to oxidative stress associated with disorders as diverse as depression, reperfusion/ischemia, and the early stages of Alzheimer's disease.
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Affiliation(s)
- Xia Cao
- Cell Signalling Laboratory, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Calcium alters monoamine oxidase-A parameters in human cerebellar and rat glial C6 cell extracts: possible influence by distinct signalling pathways. Life Sci 2009; 85:262-8. [PMID: 19539632 DOI: 10.1016/j.lfs.2009.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 05/15/2009] [Accepted: 06/09/2009] [Indexed: 01/24/2023]
Abstract
AIMS Calcium (Ca(2+)) is known to augment monoamine oxidase-A (MAO-A) activity in cell cultures as well as in brain extracts from several species. This association between Ca(2+) and MAO-A could contribute to their respective roles in cytotoxicity. However, the effect of Ca(2+) on MAO-A function in human brain has as yet to be examined as does the contribution of specific signalling cascades. MAIN METHODS We examined the effects of Ca(2+) on MAO-A activity and on [(3)H]Ro 41-1049 binding to MAO-A in human cerebellar extracts, and compared this to its effects on MAO-A activity in glial C6 cells following the targeting of signalling pathways using specific chemical inhibitors. KEY FINDINGS Ca(2+) enhances MAO-A activity as well as the association of [(3)H]Ro 41-1049 to MAO-A in human cerebellar extracts. The screening of neuronal and glial cell cultures reveals that MAO-A activity does not always correlate with the expression of either mao-A mRNA or MAO-A protein. Inhibition of the individual PI3K/Akt, ERK and p38(MAPK) signalling pathways in glial C6 cells all augment basal MAO-A activity. Inhibition of the p38(MAPK) pathway also augments Ca(2+)-sensitive MAO-A activity. We also observe the inverse relation between p38(MAPK) activation and MAO-A function in C6 cultures grown to full confluence. SIGNIFICANCE The Ca(2+)-sensitive component to MAO-A activity is present in human brain and in vitro studies link it to the p38(MAPK) pathway. This means of influencing MAO-A function could explain its role in pathologies as diverse as neurodegeneration and cancers.
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