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Brosinsky P, Heger J, Sydykov A, Weiss A, Klatt S, Czech L, Kraut S, Schermuly RT, Schlüter KD, Schulz R. Does Cell-Type-Specific Silencing of Monoamine Oxidase B Interfere with the Development of Right Ventricle (RV) Hypertrophy or Right Ventricle Failure in Pulmonary Hypertension? Int J Mol Sci 2024; 25:6212. [PMID: 38892401 PMCID: PMC11172614 DOI: 10.3390/ijms25116212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
Increased mitochondrial reactive oxygen species (ROS) formation is important for the development of right ventricular (RV) hypertrophy (RVH) and failure (RVF) during pulmonary hypertension (PH). ROS molecules are produced in different compartments within the cell, with mitochondria known to produce the strongest ROS signal. Among ROS-forming mitochondrial proteins, outer-mitochondrial-membrane-located monoamine oxidases (MAOs, type A or B) are capable of degrading neurotransmitters, thereby producing large amounts of ROS. In mice, MAO-B is the dominant isoform, which is present in almost all cell types within the heart. We analyzed the effect of an inducible cardiomyocyte-specific knockout of MAO-B (cmMAO-B KO) for the development of RVH and RVF in mice. Right ventricular hypertrophy was induced by pulmonary artery banding (PAB). RV dimensions and function were measured through echocardiography. ROS production (dihydroethidium staining), protein kinase activity (PamStation device), and systemic hemodynamics (in vivo catheterization) were assessed. A significant decrease in ROS formation was measured in cmMAO-B KO mice during PAB compared to Cre-negative littermates, which was associated with reduced activity of protein kinases involved in hypertrophic growth. In contrast to littermates in which the RV was dilated and hypertrophied following PAB, RV dimensions were unaffected in response to PAB in cmMAO-B KO mice, and no decline in RV systolic function otherwise seen in littermates during PAB was measured in cmMAO-B KO mice. In conclusion, cmMAO-B KO mice are protected against RV dilatation, hypertrophy, and dysfunction following RV pressure overload compared to littermates. These results support the hypothesis that cmMAO-B is a key player in causing RV hypertrophy and failure during PH.
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MESH Headings
- Animals
- Male
- Mice
- Disease Models, Animal
- Heart Failure/metabolism
- Heart Failure/etiology
- Heart Failure/genetics
- Heart Failure/pathology
- Heart Ventricles/pathology
- Heart Ventricles/metabolism
- Hypertension, Pulmonary/genetics
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Hypertrophy, Right Ventricular/metabolism
- Hypertrophy, Right Ventricular/genetics
- Hypertrophy, Right Ventricular/etiology
- Hypertrophy, Right Ventricular/pathology
- Mice, Knockout
- Monoamine Oxidase/genetics
- Monoamine Oxidase/metabolism
- Monoamine Oxidase/deficiency
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Reactive Oxygen Species/metabolism
- Ventricular Dysfunction, Right/metabolism
- Ventricular Dysfunction, Right/genetics
- Ventricular Dysfunction, Right/etiology
- Ventricular Dysfunction, Right/pathology
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Affiliation(s)
- Paulin Brosinsky
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (J.H.); (L.C.); (K.-D.S.); (R.S.)
| | - Jacqueline Heger
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (J.H.); (L.C.); (K.-D.S.); (R.S.)
| | - Akylbek Sydykov
- Excellence Cluster Cardiopulmonary System (ECCPS), Justus-Liebig-Universität, 35392 Gießen, Germany; (A.S.); (A.W.); (S.K.); (R.T.S.)
| | - Astrid Weiss
- Excellence Cluster Cardiopulmonary System (ECCPS), Justus-Liebig-Universität, 35392 Gießen, Germany; (A.S.); (A.W.); (S.K.); (R.T.S.)
| | - Stephan Klatt
- Vascular Research Centre, Goethe Universität, 60590 Frankfurt, Germany;
| | - Laureen Czech
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (J.H.); (L.C.); (K.-D.S.); (R.S.)
| | - Simone Kraut
- Excellence Cluster Cardiopulmonary System (ECCPS), Justus-Liebig-Universität, 35392 Gießen, Germany; (A.S.); (A.W.); (S.K.); (R.T.S.)
| | - Ralph Theo Schermuly
- Excellence Cluster Cardiopulmonary System (ECCPS), Justus-Liebig-Universität, 35392 Gießen, Germany; (A.S.); (A.W.); (S.K.); (R.T.S.)
| | - Klaus-Dieter Schlüter
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (J.H.); (L.C.); (K.-D.S.); (R.S.)
| | - Rainer Schulz
- Physiologisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany; (J.H.); (L.C.); (K.-D.S.); (R.S.)
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Schulz R, Schlüter KD. Importance of Mitochondria in Cardiac Pathologies: Focus on Uncoupling Proteins and Monoamine Oxidases. Int J Mol Sci 2023; 24:ijms24076459. [PMID: 37047436 PMCID: PMC10095304 DOI: 10.3390/ijms24076459] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
On the one hand, reactive oxygen species (ROS) are involved in the onset and progression of a wide array of diseases. On the other hand, these are a part of signaling pathways related to cell metabolism, growth and survival. While ROS are produced at various cellular sites, in cardiomyocytes the largest amount of ROS is generated by mitochondria. Apart from the electron transport chain and various other proteins, uncoupling protein (UCP) and monoamine oxidases (MAO) have been proposed to modify mitochondrial ROS formation. Here, we review the recent information on UCP and MAO in cardiac injuries induced by ischemia-reperfusion (I/R) as well as protection from I/R and heart failure secondary to I/R injury or pressure overload. The current data in the literature suggest that I/R will preferentially upregulate UCP2 in cardiac tissue but not UCP3. Studies addressing the consequences of such induction are currently inconclusive because the precise function of UCP2 in cardiac tissue is not well understood, and tissue- and species-specific aspects complicate the situation. In general, UCP2 may reduce oxidative stress by mild uncoupling and both UCP2 and UCP3 affect substrate utilization in cardiac tissue, thereby modifying post-ischemic remodeling. MAOs are important for the physiological regulation of substrate concentrations. Upon increased expression and or activity of MAOs, however, the increased production of ROS and reactive aldehydes contribute to cardiac alterations such as hypertrophy, inflammation, irreversible cardiomyocyte injury, and failure.
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Carpéné C, Mercader J, Le Gonidec S, Schaak S, Mialet‐Perez J, Zakaroff‐Girard A, Galitzky J. Body fat reduction without cardiovascular changes in mice after oral treatment with the MAO inhibitor phenelzine. Br J Pharmacol 2018; 175:2428-2440. [PMID: 29582416 PMCID: PMC5980542 DOI: 10.1111/bph.14211] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/28/2018] [Accepted: 03/02/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Phenelzine is an antidepressant drug known to increase the risk of hypertensive crisis when dietary tyramine is not restricted. However, this MAO inhibitor inhibits other enzymes not limited to the nervous system. Here we investigated if its antiadipogenic and antilipogenic effects in cultured adipocytes could contribute to decreased body fat in vivo, without unwanted hypertensive or cardiovascular effects. EXPERIMENTAL APPROACH Mice were fed a standard chow and given 0.028% phenelzine in drinking water for 12 weeks. Body composition was determined by NMR. Cardiovascular dysfunction was assessed by heart rate variability analyses and by evaluation of cardiac oxidative stress markers. MAO activity, hydrogen peroxide release and triacylglycerol turnover were assayed in white adipose tissue (WAT), alongside determination of glucose and lipid circulating levels. KEY RESULTS Phenelzine-treated mice exhibited lower body fat content, subcutaneous WAT mass and lipid content in skeletal muscles than control, without decreased body weight gain or food consumption. A modest alteration of cardiac sympathovagal balance occurred without depressed aconitase activity. In WAT, phenelzine impaired the lipogenic but not the antilipolytic actions of insulin, MAO activity and hydrogen peroxide release. Phenelzine treatment lowered non-fasting blood glucose and phosphoenolpyruvate carboxykinase expression. In vitro, high doses of phenelzine decreased both lipolytic and lipogenic responses in mouse adipocytes. CONCLUSION AND IMPLICATIONS As phenelzine reduced body fat content without affecting cardiovascular function in mice, it may be of benefit in the treatment of obesity-associated complications, with the precautions of use recommended for antidepressant therapy.
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Affiliation(s)
- Christian Carpéné
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
| | - Josep Mercader
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
| | - Sophie Le Gonidec
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
| | - Stéphane Schaak
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
| | - Jeanne Mialet‐Perez
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
| | - Alexia Zakaroff‐Girard
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
| | - Jean Galitzky
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Institut National de la Santé et de la Recherche Médicale (INSERM U1048) and Université Paul SabatierToulouse Cedex 4France
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Titova N, Schapira AHV, Chaudhuri KR, Qamar MA, Katunina E, Jenner P. Nonmotor Symptoms in Experimental Models of Parkinson's Disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 133:63-89. [PMID: 28802936 DOI: 10.1016/bs.irn.2017.05.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Nonmotor symptoms of Parkinson's disease (PD) range from neuropsychiatric, cognitive to sleep and sensory disorders and can arise from the disease process as well as from drug treatment. The clinical heterogeneity of nonmotor symptoms of PD is underpinned by a wide range of neuropathological and molecular pathology, affecting almost the entire range of neurotransmitters present in brain and the periphery. Understanding the neurobiology and pathology of nonmotor symptoms is crucial to the effective treatment of PD and currently a key unmet need. This bench-to-bedside translational concept can only be successful if robust animal models of PD charting the genesis and natural history of nonmotor symptoms can be devised. Toxin-based and transgenic rodent and primate models of PD have given us important clues to the underlying basis of motor symptomatology and in addition, can provide a snapshot of some nonmotor aspects of PD, although the data are far from complete. In this chapter, we discuss some of the nonmotor aspects of the available experimental models of PD and how the development of robust animal models to understand and treat nonmotor symptoms needs to become a research priority.
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Affiliation(s)
- Nataliya Titova
- Federal State Budgetary Educational Institution of Higher Education "N.I. Pirogov Russian National Research Medical University" of the Ministry of Healthcare of the Russian Federation, Moscow, Russia.
| | | | - K Ray Chaudhuri
- National Parkinson Foundation International Centre of Excellence, King's College London and King's College Hospital, London, United Kingdom; The Maurice Wohl Clinical Neuroscience Institute, King's College London, National Institute for Health Research (NIHR) South London and Maudsley NHS Foundation Trust and King's College London, London, United Kingdom
| | - Mubasher A Qamar
- National Parkinson Foundation International Centre of Excellence, King's College London and King's College Hospital, London, United Kingdom; The Maurice Wohl Clinical Neuroscience Institute, King's College London, National Institute for Health Research (NIHR) South London and Maudsley NHS Foundation Trust and King's College London, London, United Kingdom
| | | | - Peter Jenner
- Neurodegenerative Diseases Research Group, Institute of Pharmaceutical Science, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
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5
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Chu CP, Cui BR, Kannan H, Qiu DL. Alterations in the baroreceptor-heart rate reflex in conscious inbred polydipsic (STR/N) mice. Physiol Res 2014; 64:173-82. [PMID: 25317689 DOI: 10.33549/physiolres.932820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
STR/N is an inbred strain of mice which is known to exhibit extreme polydipsia and polyuria. We previously found central administration of angiotensin II enhanced cardiovascular responses in STR/N mice than normal mice, suggesting that STR/N mice might exhibit different cardiovascular responses. Therefore, in this study, we investigated daily mean arterial blood pressure and heart rate, and changes in the baroreceptor-heart rate reflex in conscious STR/N mice and control (ICR) mice. We found that variability in daily mean arterial blood pressure and heart rate was significantly larger in STR/N mice than in ICR mice (p<0.05). There was a stronger response to phenylephrine (PE) in STR/N mice than in ICR mice. For baroreceptor reflex sensitivity, in the rapid response period, the slopes of PE and sodium nitroprusside (SNP) were more negative in STR/N mice than in ICR mice. In the later period, the slopes of PE and SNP were negatively correlated between heart rate and blood pressure in ICR mice, but their slopes were positively correlated in STR/N mice. These results indicated that STR/N mice exhibited the different cardiovascular responses than ICR mice, suggesting that the dysfunction of baroreceptor reflex happened in conscious STR/N mice.
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Affiliation(s)
- C P Chu
- Cellular Function Research Center, Yanbian University, Yanji City, Jilin Province, China. ;
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6
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Saito M, Yamagata T, Matsumoto A, Shiba Y, Nagashima M, Taniguchi S, Jimbo E, Momoi MY. MAOA/B deletion syndrome in male siblings with severe developmental delay and sudden loss of muscle tonus. Brain Dev 2014; 36:64-9. [PMID: 23414621 DOI: 10.1016/j.braindev.2013.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 12/25/2012] [Accepted: 01/12/2013] [Indexed: 12/01/2022]
Abstract
Deletion of the monoamine oxidase (MAO)-A and MAO-B was detected in two male siblings and in their mother. The approximately 800-kb deletion, extending from about 43.0MB to 43.8MB, was detected by array comparative genomic hybridization analysis. The MAOA and MAOB genes were included in the deletion, but the adjacent Norrie disease gene, NDP, was not deleted. The boys had short stature, hypotonia, severe developmental delays, episodes of sudden loss of muscle tone, exiting behavior, lip-smacking and autistic features. The serotonin levels in their cerebrospinal fluid were extremely elevated. Another set of siblings with this deletion was reported previously. We propose recognition of MAOA/B deletion syndrome as a distinct disorder.
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Affiliation(s)
- Mari Saito
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Takanori Yamagata
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
| | - Ayumi Matsumoto
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Yusuke Shiba
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Masako Nagashima
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Shuhei Taniguchi
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Eriko Jimbo
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Mariko Y Momoi
- Department of Pediatrics, Jichi Medical Univiversity, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
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Fleming SM, Jordan MC, Mulligan CK, Masliah E, Holden JG, Millard RW, Chesselet MF, Roos KP. Impaired baroreflex function in mice overexpressing alpha-synuclein. Front Neurol 2013; 4:103. [PMID: 23888153 PMCID: PMC3719027 DOI: 10.3389/fneur.2013.00103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/09/2013] [Indexed: 12/21/2022] Open
Abstract
Cardiovascular autonomic dysfunction, such as orthostatic hypotension consequent to baroreflex failure and cardiac sympathetic denervation, is frequently observed in the synucleinopathy Parkinson’s disease (PD). In the present study, the baroreceptor reflex was assessed in mice overexpressing human wildtype alpha-synuclein (Thy1-aSyn), a genetic mouse model of synucleinopathy. The beat-to-beat change in heart rate (HR), computed from R–R interval, in relation to blood pressure was measured in anesthetized and conscious mice equipped with arterial blood pressure telemetry transducers during transient bouts of hypertension and hypotension. Compared to wildtype, tachycardia following nitroprusside-induced hypotension was significantly reduced in Thy1-aSyn mice. Thy1-aSyn mice also showed an abnormal cardiovascular response (i.e., diminished tachycardia) to muscarinic blockade with atropine. We conclude that Thy1-aSyn mice have impaired basal and dynamic range of sympathetic and parasympathetic-mediated changes in HR and will be a useful model for long-term study of cardiovascular autonomic dysfunction associated with PD.
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Affiliation(s)
- Sheila M Fleming
- Department of Psychology, University of Cincinnati , Cincinnati, OH , USA ; Department of Neurology, University of Cincinnati , Cincinnati, OH , USA
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Bar-Am O, Gross A, Friedman R, Finberg JPM. Cardiovascular baroreceptor activity and selective inhibition of monoamine oxidase. Eur J Pharmacol 2012; 683:226-30. [PMID: 22465184 DOI: 10.1016/j.ejphar.2012.03.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 03/07/2012] [Accepted: 03/09/2012] [Indexed: 11/30/2022]
Abstract
Cardiovascular baroreceptor responsiveness of conscious rats treated with selective inhibitors of monoamine oxidase (MAO) types A and B was determined by measurement of blood pressure (BP) and heart rate (HR) responses to intravenous injection of phenylephrine and sodium nitroprusside. Treatment with selegiline (1 or 5 mg/kg p.o. daily for 7 days) did not significantly modify resting levels of BP and HR, lower or upper HR plateau levels, or HR/BP gain. Treatment with clorgyline (2 mg/kg p.o. daily for 7 days) increased HR/BP gain but also did not modify resting BP or HR, or lower and upper plateau levels of HR. The results are compatible with an effect of MAO-A inhibition to modify monoamine levels in medullary areas participating in CNS control of blood pressure.
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Affiliation(s)
- Orit Bar-Am
- Dept of Molecular Pharmacology, Rappaport Faculty of Medicine, Technion, POB 9649, Haifa 31096, Israel
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McNeill EM, Roos KP, Moechars D, Clagett-Dame M. Nav2 is necessary for cranial nerve development and blood pressure regulation. Neural Dev 2010; 5:6. [PMID: 20184720 PMCID: PMC2843687 DOI: 10.1186/1749-8104-5-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 02/25/2010] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND All-trans retinoic acid (atRA) is required for nervous system development, including the developing hindbrain region. Neuron navigator 2 (Nav2) was first identified as an atRA-responsive gene in human neuroblastoma cells (retinoic acid-induced in neuroblastoma 1, Rainb1), and is required for atRA-mediated neurite outgrowth. In this paper, we explore the importance of Nav2 in nervous system development and function in vivo. RESULTS Nav2 hypomorphic homozygous mutants show decreased survival starting at birth. Nav2 mutant embryos show an overall reduction in nerve fiber density, as well as specific defects in cranial nerves IX (glossopharyngeal) and X (vagus). Nav2 hypomorphic mutant adult mice also display a blunted baroreceptor response compared to wild-type controls. CONCLUSIONS Nav2 functions in mammalian nervous system development, and is required for normal cranial nerve development and blood pressure regulation in the adult.
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Affiliation(s)
- Elizabeth M McNeill
- Interdepartmental Graduate Program in Nutritional Sciences, University of Wisconsin, Madison, WI, USA
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Shih JC. Monoamine oxidases: from tissue homogenates to transgenic mice. Neurochem Res 2007; 32:1757-61. [PMID: 17551828 DOI: 10.1007/s11064-007-9384-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Accepted: 05/10/2007] [Indexed: 10/23/2022]
Abstract
The regulation, structure and function of monoamine oxidases (MAO's) have been a subject of my research for many years. Studies of the enzyme have moved from early biochemical experiments, where different forms were biochemically characterized, to the molecular biology revolution where the genes for MAO A and MAO B were cloned and sequenced. Analyses of the signal pathways of gene regulation and specific transcriptional repression of MAO gene expression followed, as did the elucidation of the role of MAO in apoptosis. And importantly, MAO's impact on behavioral states of both mice and human beings was discovered. It is fulfilling and humbling to see how our early experiments with tissue homogenates and MAO A and MAO B gene cloning built a foundation for so much subsequent understanding of the molecular and genetic components underlying certain behaviors.
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Affiliation(s)
- Jean Chen Shih
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90089, USA.
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Chen K, Ou XM, Chen G, Choi SH, Shih JC. R1, a novel repressor of the human monoamine oxidase A. J Biol Chem 2005; 280:11552-9. [PMID: 15654081 PMCID: PMC2861901 DOI: 10.1074/jbc.m410033200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Monoamine oxidase catalyzes the oxidative deamination of a number of neurotransmitters. A deficiency in monoamine oxidase A results in aggressive behavior in both humans and mice. Studies on the regulation of monoamine oxidase A gene expression have shown that the Sp1 family is important for monoamine oxidase A expression. To search for novel transcription factors, the sequences of three Sp1 sites in the monoamine oxidase A core promoter were used in the yeast one-hybrid system to screen a human cDNA library. A novel repressor, R1 (RAM2), has been cloned. The R1 cDNA encodes a protein with 454 amino acids and an open reading frame at the 5'-end. The transfection of R1 in a human neuroblastoma cell line, SK-N-BE (2)-C, inhibited the monoamine oxidase A promoter and enzymatic activity. The degree of inhibition of monoamine oxidase A by R1 correlated with the level of R1 protein expression. R1 was also found to repress monoamine oxidase A promoter activity within a natural chromatin environment. A gel-shift assay indicated that the endogenous R1 protein in SK-N-BE (2)-C cells interacted with the R1 binding sequence. R1 also bound directly to the natural monoamine oxidase A promoter in vivo as shown by chromatin immunoprecipitation assay. Immunocytochemical analysis showed that R1 was expressed in both cytosol and nucleus, which suggested a role for R1 in transcriptional regulation. Northern blot analysis revealed the presence of endogenous R1 mRNA in human brain and peripheral tissues. Taken together, this study shows that R1 is a novel repressor that inhibits monoamine oxidase A gene expression.
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Affiliation(s)
- Kevin Chen
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Xiao-Ming Ou
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Gao Chen
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Si Ho Choi
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90033
| | - Jean C. Shih
- Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90033
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
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