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Žaloudíková M. Mechanisms and Effects of Macrophage Polarization and Its Specifics in Pulmonary Environment. Physiol Res 2023; 72:S137-S156. [PMID: 37565418 PMCID: PMC10660583 DOI: 10.33549/physiolres.935058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 06/09/2023] [Indexed: 12/01/2023] Open
Abstract
Macrophages are a specific group of cells found in all body tissues. They have specific characteristics in each of the tissues that correspond to the functional needs of the specific environment. These cells are involved in a wide range of processes, both pro-inflammatory and anti-inflammatory ("wound healing"). This is due to their specific capacity for so-called polarization, a phenotypic change that is, moreover, partially reversible compared to other differentiated cells of the human body. This promises a wide range of possibilities for its influence and thus therapeutic use. In this article, we therefore review the mechanisms that cause polarization, the basic classification of polarized macrophages, their characteristic markers and the effects that accompany these phenotypic changes. Since the study of pulmonary (and among them mainly alveolar) macrophages is currently the focus of scientific interest of many researchers and these macrophages are found in very specific environments, given mainly by the extremely high partial pressure of oxygen compared to other locations, which specifically affects their behavior, we will focus our review on this group.
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Affiliation(s)
- M Žaloudíková
- Department of Physiology, Second Faculty of Medicine, Charles University, Prague, Czech Republic.
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2
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Canton M, Sánchez-Rodríguez R, Spera I, Venegas FC, Favia M, Viola A, Castegna A. Reactive Oxygen Species in Macrophages: Sources and Targets. Front Immunol 2021; 12:734229. [PMID: 34659222 PMCID: PMC8515906 DOI: 10.3389/fimmu.2021.734229] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/15/2021] [Indexed: 12/30/2022] Open
Abstract
Reactive oxygen species (ROS) are fundamental for macrophages to eliminate invasive microorganisms. However, as observed in nonphagocytic cells, ROS play essential roles in processes that are different from pathogen killing, as signal transduction, differentiation, and gene expression. The different outcomes of these events are likely to depend on the specific subcellular site of ROS formation, as well as the duration and extent of ROS production. While excessive accumulation of ROS has long been appreciated for its detrimental effects, there is now a deeper understanding of their roles as signaling molecules. This could explain the failure of the “all or none” pharmacologic approach with global antioxidants to treat several diseases. NADPH oxidase is the first source of ROS that has been identified in macrophages. However, growing evidence highlights mitochondria as a crucial site of ROS formation in these cells, mainly due to electron leakage of the respiratory chain or to enzymes, such as monoamine oxidases. Their role in redox signaling, together with their exact site of formation is only partially elucidated. Hence, it is essential to identify the specific intracellular sources of ROS and how they influence cellular processes in both physiological and pathological conditions to develop therapies targeting oxidative signaling networks. In this review, we will focus on the different sites of ROS formation in macrophages and how they impact on metabolic processes and inflammatory signaling, highlighting the role of mitochondrial as compared to non-mitochondrial ROS sources.
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Affiliation(s)
- Marcella Canton
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica Città della Speranza - IRP, Padova, Italy
| | - Ricardo Sánchez-Rodríguez
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica Città della Speranza - IRP, Padova, Italy
| | - Iolanda Spera
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Francisca C Venegas
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica Città della Speranza - IRP, Padova, Italy
| | - Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Antonella Viola
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica Città della Speranza - IRP, Padova, Italy
| | - Alessandra Castegna
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza - IRP, Padova, Italy.,Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
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3
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Ostadkarampour M, Putnins EE. Monoamine Oxidase Inhibitors: A Review of Their Anti-Inflammatory Therapeutic Potential and Mechanisms of Action. Front Pharmacol 2021; 12:676239. [PMID: 33995107 PMCID: PMC8120032 DOI: 10.3389/fphar.2021.676239] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/06/2021] [Indexed: 12/18/2022] Open
Abstract
Chronic inflammatory diseases are debilitating, affect patients' quality of life, and are a significant financial burden on health care. Inflammation is regulated by pro-inflammatory cytokines and chemokines that are expressed by immune and non-immune cells, and their expression is highly controlled, both spatially and temporally. Their dysregulation is a hallmark of chronic inflammatory and autoimmune diseases. Significant evidence supports that monoamine oxidase (MAO) inhibitor drugs have anti-inflammatory effects. MAO inhibitors are principally prescribed for the management of a variety of central nervous system (CNS)-associated diseases such as depression, Alzheimer's, and Parkinson's; however, they also have anti-inflammatory effects in the CNS and a variety of non-CNS tissues. To bolster support for their development as anti-inflammatories, it is critical to elucidate their mechanism(s) of action. MAO inhibitors decrease the generation of end products such as hydrogen peroxide, aldehyde, and ammonium. They also inhibit biogenic amine degradation, and this increases cellular and pericellular catecholamines in a variety of immune and some non-immune cells. This decrease in end product metabolites and increase in catecholamines can play a significant role in the anti-inflammatory effects of MAO inhibitors. This review examines MAO inhibitor effects on inflammation in a variety of in vitro and in vivo CNS and non-CNS disease models, as well as their anti-inflammatory mechanism(s) of action.
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Affiliation(s)
- Mahyar Ostadkarampour
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada
| | - Edward E Putnins
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada
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4
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Neshan M, Campbell A, Malakouti SK, Zareii M, Ahangari G. Gene expression of serotonergic markers in peripheral blood mononuclear cells of patients with late-onset Alzheimer's disease. Heliyon 2020; 6:e04716. [PMID: 32904297 PMCID: PMC7452509 DOI: 10.1016/j.heliyon.2020.e04716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 06/06/2020] [Accepted: 08/11/2020] [Indexed: 01/14/2023] Open
Abstract
Serotonin or 5-hydroxytryptamine (5-HT) is primarily involved in the regulation of learning and memory. Pathological changes in metabolism or functional imbalance of 5-HT has been associated with Alzheimer's disease (AD). The hypothesis tested is that in peripheral blood, markers of the serotonergic pathway can be used as a diagnostic tool for AD. The current study measured the relative expression of 5-HT receptors (5-HTR2A and 5-HTR3A) as well as the 5-HT catalytic enzyme, Monoamine oxidase A (MAO-A) mRNA in Peripheral Blood Mononuclear Cells (PBMCs) of patients with late-onset Alzheimer's disease (LOAD) and age-matched controls. 5-HTR2A, 5-HTR3A, and MAO-A mRNA expressions were examined in PBMCs of 30 patients with LOAD and 30 control individuals. Real-time quantitative PCR was used to measure mRNA expression. The dementia status of patients in this study was assessed using a Mini-Mental State Examination (MMSE). Mean data of relative mRNA expression of 5-HTR2A, 5-HTR3A and MAO-A were significantly lower in PBMCs of patients with LOAD compared with controls. Based on the down-regulation of serotonergic markers in PBMCs, our findings may be another claim to the systemic nature of LOAD. The role of peripheral serotonergic downregulation, in the pathogenesis of AD, needs to be further studied. Given the extremely convenient access to PBMCs, these molecular events may represent more complete dimensions of AD neuropathophysiology or possibly lead to a new direction in studies focused on blood-based markers.
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Affiliation(s)
- Masoud Neshan
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Arezoo Campbell
- Department of Pharmaceutical Sciences, Western University of Health Sciences, California, USA
| | - Seyed Kazem Malakouti
- Mental Health Research Center, Tehran Institute of Psychiatry–School of Behavioral Sciences and Mental Health, Iran University of Medical Sciences, Tehran, Iran
| | - Mahsa Zareii
- Mental Health Research Center, Tehran Institute of Psychiatry–School of Behavioral Sciences and Mental Health, Iran University of Medical Sciences, Tehran, Iran
| | - Ghasem Ahangari
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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5
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Wu H, Denna TH, Storkersen JN, Gerriets VA. Beyond a neurotransmitter: The role of serotonin in inflammation and immunity. Pharmacol Res 2019; 140:100-114. [DOI: 10.1016/j.phrs.2018.06.015] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/01/2018] [Accepted: 06/17/2018] [Indexed: 12/16/2022]
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6
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Boura‐Halfon S, Pecht T, Jung S, Rudich A. Obesity and dysregulated central and peripheral macrophage–neuron cross‐talk. Eur J Immunol 2018; 49:19-29. [DOI: 10.1002/eji.201747389] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/13/2018] [Accepted: 11/02/2018] [Indexed: 12/28/2022]
Affiliation(s)
| | - Tal Pecht
- Department of Clinical Biochemistry and Pharmacology Faculty of Health Sciences, and the National Institute of Biotechnology in the Negev Ben‐Gurion University of the Negev Beer Sheva Israel
| | - Steffen Jung
- Department of Immunology Weizmann Institute of Science Rehovot Israel
| | - Assaf Rudich
- Department of Clinical Biochemistry and Pharmacology Faculty of Health Sciences, and the National Institute of Biotechnology in the Negev Ben‐Gurion University of the Negev Beer Sheva Israel
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7
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Dhabal S, Das P, Biswas P, Kumari P, Yakubenko VP, Kundu S, Cathcart MK, Kundu M, Biswas K, Bhattacharjee A. Regulation of monoamine oxidase A (MAO-A) expression, activity, and function in IL-13-stimulated monocytes and A549 lung carcinoma cells. J Biol Chem 2018; 293:14040-14064. [PMID: 30021838 DOI: 10.1074/jbc.ra118.002321] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 07/06/2018] [Indexed: 11/06/2022] Open
Abstract
Monoamine oxidase A (MAO-A) is a mitochondrial flavoenzyme implicated in the pathogenesis of atherosclerosis and inflammation and also in many neurological disorders. MAO-A also has been reported as a potential therapeutic target in prostate cancer. However, the regulatory mechanisms controlling cytokine-induced MAO-A expression in immune or cancer cells remain to be identified. Here, we show that MAO-A expression is co-induced with 15-lipoxygenase (15-LO) in interleukin 13 (IL-13)-activated primary human monocytes and A549 non-small cell lung carcinoma cells. We present evidence that MAO-A gene expression and activity are regulated by signal transducer and activator of transcription 1, 3, and 6 (STAT1, STAT3, and STAT6), early growth response 1 (EGR1), and cAMP-responsive element-binding protein (CREB), the same transcription factors that control IL-13-dependent 15-LO expression. We further established that in both primary monocytes and in A549 cells, IL-13-stimulated MAO-A expression, activity, and function are directly governed by 15-LO. In contrast, IL-13-driven expression and activity of MAO-A was 15-LO-independent in U937 promonocytic cells. Furthermore, we demonstrate that the 15-LO-dependent transcriptional regulation of MAO-A in response to IL-13 stimulation in monocytes and in A549 cells is mediated by peroxisome proliferator-activated receptor γ (PPARγ) and that signal transducer and activator of transcription 6 (STAT6) plays a crucial role in facilitating the transcriptional activity of PPARγ. We further report that the IL-13-STAT6-15-LO-PPARγ axis is critical for MAO-A expression, activity, and function, including migration and reactive oxygen species generation. Altogether, these results have major implications for the resolution of inflammation and indicate that MAO-A may promote metastatic potential in lung cancer cells.
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Affiliation(s)
- Sukhamoy Dhabal
- From the Department of Biotechnology, National Institute of Technology-Durgapur, Mahatma Gandhi Avenue, Durgapur-713209, Burdwan, West Bengal, India
| | - Pradip Das
- From the Department of Biotechnology, National Institute of Technology-Durgapur, Mahatma Gandhi Avenue, Durgapur-713209, Burdwan, West Bengal, India
| | - Pritam Biswas
- From the Department of Biotechnology, National Institute of Technology-Durgapur, Mahatma Gandhi Avenue, Durgapur-713209, Burdwan, West Bengal, India
| | - Priyanka Kumari
- From the Department of Biotechnology, National Institute of Technology-Durgapur, Mahatma Gandhi Avenue, Durgapur-713209, Burdwan, West Bengal, India
| | - Valentin P Yakubenko
- the Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio 44195, and
| | - Suman Kundu
- the Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio 44195, and
| | - Martha K Cathcart
- the Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio 44195, and
| | - Manjari Kundu
- the Division of Molecular Medicine, Bose Institute, Kolkata 700054, West Bengal, India
| | - Kaushik Biswas
- the Division of Molecular Medicine, Bose Institute, Kolkata 700054, West Bengal, India
| | - Ashish Bhattacharjee
- From the Department of Biotechnology, National Institute of Technology-Durgapur, Mahatma Gandhi Avenue, Durgapur-713209, Burdwan, West Bengal, India,
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8
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Li R, Sahu S, Schachner M. Phenelzine, a small organic compound mimicking the functions of cell adhesion molecule L1, promotes functional recovery after mouse spinal cord injury. Restor Neurol Neurosci 2018; 36:469-483. [PMID: 29889084 DOI: 10.3233/rnn-170808] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Neural cell adhesion molecule L1 contributes to nervous system development and maintenance by promoting neuronal survival, neuritogenesis, axonal regrowth/sprouting, myelination, and synapse formation and plasticity. L1 also enhances recovery after spinal cord injury and ameliorates neurodegenerative processes in experimental rodent models. Aiming for clinical translation of L1 into therapy we screened for and functionally characterized in vitro the small organic molecule phenelzine, which mimics characteristic L1 functions. OBJECTIVE The present study was designed to evaluate the potential of this compound in vivo in a mouse model of spinal cord injury. METHODS AND RESULTS In mice, intraperitoneal injection of phenelzine immediately after severe thoracic compression, and thereafter once daily for 6 weeks, improved hind limb function, reduced astrogliosis and promoted axonal regrowth/sprouting at 4 and 5 weeks after spinal cord injury compared to vehicle control-treated mice. Phenelzine application upregulated L1 expression in the spinal cord and stimulated the cognate L1-mediated intracellular signaling cascades in the spinal cord tissue. Phenelzine-treated mice showed decreased levels of pro-inflammatory cytokines, such as interleukin-1β, interleukin-6, and tumor necrosis factor-α in the injured spinal cord during the acute phase of inflammation. CONCLUSIONS This study provides new insights into the role of phenelzine in L1-mediated neural functions and modulation of inflammation. The combined results raise hopes that phenelzine may develop into a therapeutic agent for nervous system injuries.
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Affiliation(s)
- Rong Li
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China
| | - Sudhanshu Sahu
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China
| | - Melitta Schachner
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
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9
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Scanzano A, Cosentino M. Adrenergic regulation of innate immunity: a review. Front Pharmacol 2015; 6:171. [PMID: 26321956 PMCID: PMC4534859 DOI: 10.3389/fphar.2015.00171] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/31/2015] [Indexed: 12/24/2022] Open
Abstract
The sympathetic nervous system has a major role in the brain-immune cross-talk, but few information exist on the sympathoadrenergic regulation of innate immune system. The aim of this review is to summarize available knowledge regarding the sympathetic modulation of the innate immune response, providing a rational background for the possible repurposing of adrenergic drugs as immunomodulating agents. The cells of immune system express adrenoceptors (AR), which represent the target for noradrenaline and adrenaline. In human neutrophils, adrenaline and noradrenaline inhibit migration, CD11b/CD18 expression, and oxidative metabolism, possibly through β-AR, although the role of α1- and α2-AR requires further investigation. Natural Killer express β-AR, which are usually inhibitory. Monocytes express β-AR and their activation is usually antiinflammatory. On murine Dentritic cells (DC), β-AR mediate sympathetic influence on DC-T cells interactions. In human DC β2-AR may affect Th1/2 differentiation of CD4+ T cells. In microglia and in astrocytes, β2-AR dysregulation may contribute to neuroinflammation in autoimmune and neurodegenerative disease. In conclusion, extensive evidence supports a critical role for adrenergic mechanisms in the regulation of innate immunity, in peripheral tissues as well as in the CNS. Sympathoadrenergic pathways in the innate immune system may represent novel antiinflammatory and immunomodulating targets with significant therapeutic potential.
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Affiliation(s)
- Angela Scanzano
- Center for Research in Medical Pharmacology, University of Insubria Varese, Italy
| | - Marco Cosentino
- Center for Research in Medical Pharmacology, University of Insubria Varese, Italy
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10
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Immunomodulatory effects mediated by serotonin. J Immunol Res 2015; 2015:354957. [PMID: 25961058 PMCID: PMC4417587 DOI: 10.1155/2015/354957] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 02/24/2015] [Indexed: 11/17/2022] Open
Abstract
Serotonin (5-HT) induces concentration-dependent metabolic effects in diverse cell types, including neurons, entherochromaffin cells, adipocytes, pancreatic beta-cells, fibroblasts, smooth muscle cells, epithelial cells, and leukocytes. Three classes of genes regulating 5-HT function are constitutively expressed or induced in these cells: (a) membrane proteins that regulate the response to 5-HT, such as SERT, 5HTR-GPCR, and the 5HT3-ion channels; (b) downstream signaling transduction proteins; and (c) enzymes controlling 5-HT metabolism, such as IDO and MAO, which can generate biologically active catabolites, including melatonin, kynurenines, and kynurenamines. This review covers the clinical and experimental mechanisms involved in 5-HT-induced immunomodulation. These mechanisms are cell-specific and depend on the expression of serotonergic components in immune cells. Consequently, 5-HT can modulate several immunological events, such as chemotaxis, leukocyte activation, proliferation, cytokine secretion, anergy, and apoptosis. The effects of 5-HT on immune cells may be relevant in the clinical outcome of pathologies with an inflammatory component. Major depression, fibromyalgia, Alzheimer disease, psoriasis, arthritis, allergies, and asthma are all associated with changes in the serotonergic system associated with leukocytes. Thus, pharmacological regulation of the serotonergic system may modulate immune function and provide therapeutic alternatives for these diseases.
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11
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Cathcart MK, Bhattacharjee A. Monoamine oxidase A (MAO-A): a signature marker of alternatively activated monocytes/macrophages. INFLAMMATION AND CELL SIGNALING 2014; 1. [PMID: 26052543 DOI: 10.14800/ics.161] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Monocytes/macrophages are versatile cells centrally involved in host defense and immunity. Th1 cytokines induce a classical activation program in monocytes/macrophages leading to a proinflammatory M1 macrophage phenotype while Th2 cytokines IL-4 and IL-13 promote monocyte differentiation into an alternatively activated, anti-inflammatory M2 macrophage phenotype. Although monoamine oxidase A (MAO-A) is primarily known for its action in the nervous system, several recent studies have identified MAO-A as a signature marker of alternative activation of monocytes/macrophages. In this brief review we explore the signaling pathways/molecules that regulate MAO-A expression in alternatively activated monocytes/macrophages. We further discuss the contribution of MAO-A to the resolution of inflammation and identify potential therapeutic targets for controlling inflammation. Altogether this review provides deeper insight into the role of MAO-A in alternative activation of monocytes/macrophages and their participation in the inflammatory response.
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Affiliation(s)
- Martha K Cathcart
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Ashish Bhattacharjee
- Department of Biotechnology, National Institute of Technology, Durgapur-713209, West Bengal, India
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12
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MicroRNA-142 reduces monoamine oxidase A expression and activity in neuronal cells by downregulating SIRT1. PLoS One 2013; 8:e79579. [PMID: 24244526 PMCID: PMC3823651 DOI: 10.1371/journal.pone.0079579] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 09/26/2013] [Indexed: 12/15/2022] Open
Abstract
Aberrant expression of microRNAs (miRs) has been implicated in the pathogenesis of several neurodegenerative disorders. In HIV-associated neurocognitive disorders (HAND), miR-142 was found to be upregulated in neurons and myeloid cells in the brain. We investigated the downstream effects of chronic miR-142 upregulation in neuronal cells by comparing gene expression in stable clones of the human neuroblastoma cell line BE(2)M17 expressing miR-142 to controls. Microarray analysis revealed that miR-142 expression led to a reduction in monoamine oxidase (MAO) A mRNA, which was validated by qRT-PCR. In addition to the mRNA, the MAOA protein level and enzyme activity were also reduced. Examination of primary human neurons revealed that miR-142 expression indeed resulted in a downregulation of MAOA protein level. Although MAOA is not a direct target of miR-142, SIRT1, a key transcriptional upregulator of MAOA is, thus miR-142 downregulation of MAOA expression is indirect. MiR-142 induced decrease in MAOA expression and activity may contribute to the changes in dopaminergic neurotransmission reported in HAND.
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13
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Benson CA, Wong G, Tenorio G, Baker GB, Kerr BJ. The MAO inhibitor phenelzine can improve functional outcomes in mice with established clinical signs in experimental autoimmune encephalomyelitis (EAE). Behav Brain Res 2013; 252:302-11. [DOI: 10.1016/j.bbr.2013.06.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/07/2013] [Accepted: 06/11/2013] [Indexed: 12/18/2022]
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14
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Wang CC, Billett E, Borchert A, Kuhn H, Ufer C. Monoamine oxidases in development. Cell Mol Life Sci 2013; 70:599-630. [PMID: 22782111 PMCID: PMC11113580 DOI: 10.1007/s00018-012-1065-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 06/13/2012] [Accepted: 06/19/2012] [Indexed: 12/29/2022]
Abstract
Monoamine oxidases (MAOs) are flavoproteins of the outer mitochondrial membrane that catalyze the oxidative deamination of biogenic and xenobiotic amines. In mammals there are two isoforms (MAO-A and MAO-B) that can be distinguished on the basis of their substrate specificity and their sensitivity towards specific inhibitors. Both isoforms are expressed in most tissues, but their expression in the central nervous system and their ability to metabolize monoaminergic neurotransmitters have focused MAO research on the functionality of the mature brain. MAO activities have been related to neurodegenerative diseases as well as to neurological and psychiatric disorders. More recently evidence has been accumulating indicating that MAO isoforms are expressed not only in adult mammals, but also before birth, and that defective MAO expression induces developmental abnormalities in particular of the brain. This review is aimed at summarizing and critically evaluating the new findings on the developmental functions of MAO isoforms during embryogenesis.
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Affiliation(s)
- Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, Shatin, Hong Kong
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ellen Billett
- School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS UK
| | - Astrid Borchert
- Institute of Biochemistry, University Medicine Berlin-Charité, Oudenarder Str. 16, 13347 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, University Medicine Berlin-Charité, Oudenarder Str. 16, 13347 Berlin, Germany
| | - Christoph Ufer
- Institute of Biochemistry, University Medicine Berlin-Charité, Oudenarder Str. 16, 13347 Berlin, Germany
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15
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Bhattacharjee A, Shukla M, Yakubenko VP, Mulya A, Kundu S, Cathcart MK. IL-4 and IL-13 employ discrete signaling pathways for target gene expression in alternatively activated monocytes/macrophages. Free Radic Biol Med 2013; 54:1-16. [PMID: 23124025 PMCID: PMC3534796 DOI: 10.1016/j.freeradbiomed.2012.10.553] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 10/06/2012] [Accepted: 10/24/2012] [Indexed: 12/12/2022]
Abstract
Monocytes/macrophages are innate immune cells that play a crucial role in the resolution of inflammation. In the presence of the Th2 cytokines interleukin-4 (IL-4) and interleukin-13 (IL-13), they display an anti-inflammatory profile and this activation pathway is known as alternative activation. In this study we compare and differentiate pathways mediated by IL-4 and IL-13 activation of human monocytes/macrophages. Here we report differential regulation of IL-4 and IL-13 signaling in monocytes/macrophages starting from IL-4/IL-13 cytokine receptors to Jak/Stat-mediated signaling pathways that ultimately control expression of several inflammatory genes. Our data demonstrate that although the receptor-associated tyrosine kinases Jak2 and Tyk2 are activated after the recruitment of IL-13 to its receptor (containing IL-4Rα and IL-13Rα1), IL-4 stimulates Jak1 activation. We further show that Jak2 is upstream of Stat3 activation and Tyk2 controls Stat1 and Stat6 activation in response to IL-13 stimulation. In contrast, Jak1 regulates Stat3 and Stat6 activation in IL-4-induced monocytes. Our results further reveal that although IL-13 utilizes both IL-4Rα/Jak2/Stat3 and IL-13Rα1/Tyk2/Stat1/Stat6 signaling pathways, IL-4 can use only the IL-4Rα/Jak1/Stat3/Stat6 cascade to regulate the expression of some critical inflammatory genes, including 15-lipoxygenase, monoamine oxidase A (MAO-A), and the scavenger receptor CD36. Moreover, we demonstrate here that IL-13 and IL-4 can uniquely affect the expression of particular genes such as dual-specificity phosphatase 1 and tissue inhibitor of metalloprotease-3 and do so through different Jaks. As evidence of differential regulation of gene function by IL-4 and IL-13, we further report that MAO-A-mediated reactive oxygen species generation is influenced by different Jaks. Collectively, these results have major implications for understanding the mechanism and function of alternatively activated monocytes/macrophages by IL-4 and IL-13 and add novel insights into the pathogenesis and potential treatment of various inflammatory diseases.
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Affiliation(s)
- Ashish Bhattacharjee
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195
| | - Meenakshi Shukla
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195
| | - Valentin P. Yakubenko
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195
| | - Anny Mulya
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195
| | - Suman Kundu
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195
| | - Martha K. Cathcart
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic and Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195
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Czimmerer Z, Varga T, Poliska S, Nemet I, Szanto A, Nagy L. Identification of novel markers of alternative activation and potential endogenous PPARγ ligand production mechanisms in human IL-4 stimulated differentiating macrophages. Immunobiology 2012; 217:1301-14. [PMID: 22954708 DOI: 10.1016/j.imbio.2012.08.270] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/30/2012] [Accepted: 08/02/2012] [Indexed: 01/28/2023]
Affiliation(s)
- Zsolt Czimmerer
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Life Science Building, Egyetem ter 1, Debrecen H-4012, Hungary
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17
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Aijö T, Edelman SM, Lönnberg T, Larjo A, Kallionpää H, Tuomela S, Engström E, Lahesmaa R, Lähdesmäki H. An integrative computational systems biology approach identifies differentially regulated dynamic transcriptome signatures which drive the initiation of human T helper cell differentiation. BMC Genomics 2012; 13:572. [PMID: 23110343 PMCID: PMC3526425 DOI: 10.1186/1471-2164-13-572] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 10/02/2012] [Indexed: 01/19/2023] Open
Abstract
Background A proper balance between different T helper (Th) cell subsets is necessary for normal functioning of the adaptive immune system. Revealing key genes and pathways driving the differentiation to distinct Th cell lineages provides important insight into underlying molecular mechanisms and new opportunities for modulating the immune response. Previous computational methods to quantify and visualize kinetic differential expression data of three or more lineages to identify reciprocally regulated genes have relied on clustering approaches and regression methods which have time as a factor, but have lacked methods which explicitly model temporal behavior. Results We studied transcriptional dynamics of human umbilical cord blood T helper cells cultured in absence and presence of cytokines promoting Th1 or Th2 differentiation. To identify genes that exhibit distinct lineage commitment dynamics and are specific for initiating differentiation to different Th cell subsets, we developed a novel computational methodology (LIGAP) allowing integrative analysis and visualization of multiple lineages over whole time-course profiles. Applying LIGAP to time-course data from multiple Th cell lineages, we identified and experimentally validated several differentially regulated Th cell subset specific genes as well as reciprocally regulated genes. Combining differentially regulated transcriptional profiles with transcription factor binding site and pathway information, we identified previously known and new putative transcriptional mechanisms involved in Th cell subset differentiation. All differentially regulated genes among the lineages together with an implementation of LIGAP are provided as an open-source resource. Conclusions The LIGAP method is widely applicable to quantify differential time-course dynamics of many types of datasets and generalizes to any number of conditions. It summarizes all the time-course measurements together with the associated uncertainty for visualization and manual assessment purposes. Here we identified novel human Th subset specific transcripts as well as regulatory mechanisms important for the initiation of the Th cell subset differentiation.
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Affiliation(s)
- Tarmo Aijö
- Department of Signal Processing, Tampere University of Technology, Tampere, Finland
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18
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Abstract
The monoamine oxidase A (MAOA) gene has been suggested as a prime candidate in the pathogenesis of panic disorder. In the present study, DNA methylation patterns in the MAOA regulatory and exon 1/intron 1 region were investigated for association with panic disorder with particular attention to possible effects of gender and environmental factors. Sixty-five patients with panic disorder (44 females, 21 males) and 65 healthy controls were analysed for DNA methylation status at 42 MAOA CpG sites via direct sequencing of sodium bisulfate treated DNA extracted from blood cells. The occurrence of recent positive and negative life events was ascertained. Male subjects showed no or only very minor methylation with some evidence for relative hypomethylation at one CpG site in intron 1 in patients compared to controls. Female patients exhibited significantly lower methylation than healthy controls at 10 MAOA CpG sites in the promoter as well as in exon/intron 1, with significance surviving correction for multiple testing at four CpG sites (p≤0.001). Furthermore, in female subjects the occurrence of negative life events was associated with relatively decreased methylation, while positive life events were associated with increased methylation. The present pilot data suggest a potential role of MAOA gene hypomethylation in the pathogenesis of panic disorder particularly in female patients, possibly mediating a detrimental influence of negative life events. Future studies are warranted to replicate the present finding in independent samples, preferably in a longitudinal design.
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19
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Marino F, Cosentino M. Adrenergic modulation of immune cells: an update. Amino Acids 2011; 45:55-71. [PMID: 22160285 DOI: 10.1007/s00726-011-1186-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 11/23/2011] [Indexed: 12/25/2022]
Abstract
Sympathoadrenergic pathways are crucial to the communication between the nervous system and the immune system. The present review addresses emerging issues in the adrenergic modulation of immune cells, including: the specific pattern of adrenoceptor expression on immune cells and their role and changes upon cell differentiation and activation; the production and utilization of noradrenaline and adrenaline by immune cells themselves; the dysregulation of adrenergic immune mechanisms in disease and their potential as novel therapeutic targets. A wide array of sympathoadrenergic therapeutics is currently used for non-immune indications, and could represent an attractive source of non-conventional immunomodulating agents.
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Affiliation(s)
- Franca Marino
- Department of Clinical Medicine, Section of Experimental and Clinical Pharmacology, University of Insubria, Via Ottorino Rossi n. 9, 21100 Varese, VA, Italy
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20
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Bhattacharjee A, Pal S, Feldman GM, Cathcart MK. Hck is a key regulator of gene expression in alternatively activated human monocytes. J Biol Chem 2011; 286:36709-23. [PMID: 21878628 DOI: 10.1074/jbc.m111.291492] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IL-13 is a Th2 cytokine that promotes alternative activation (M2 polarization) in primary human monocytes. Our studies have characterized the functional IL-13 receptor complex and the downstream signaling events in response to IL-13 stimulation in alternatively activated monocytes/macrophages. In this report, we present evidence that IL-13 induces the activation of a Src family tyrosine kinase, which is required for IL-13 induction of M2 gene expression, including 15-lipoxygenase (15-LO). Our data show that Src kinase activity regulates IL-13-induced p38 MAPK tyrosine phosphorylation via the upstream kinases MKK3 or MKK6. Our findings also reveal that the IL-13 receptor-associated tyrosine kinase Jak2 is required for the activation of both Src kinase as well as p38 MAPK. Further, we found that Src tyrosine kinase-mediated activation of p38 MAPK is required for Stat1 and Stat3 serine 727 phosphorylation in alternatively activated monocytes/macrophages. Additional studies identify Hck as the specific Src family member, stimulated by IL-13 and involved in regulating both p38 MAPK activation and p38 MAPK-mediated 15-LO expression. Finally we show that the Hck regulates the expression of other alternative state (M2)-specific genes (Mannose receptor, MAO-A, and CD36) and therefore conclude that Hck acts as a key regulator controlling gene expression in alternatively activated monocytes/macrophages.
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Affiliation(s)
- Ashish Bhattacharjee
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, and Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195, USA.
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21
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IgE mediates killing of intracellular Toxoplasma gondii by human macrophages through CD23-dependent, interleukin-10 sensitive pathway. PLoS One 2011; 6:e18289. [PMID: 21526166 PMCID: PMC3081288 DOI: 10.1371/journal.pone.0018289] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 03/02/2011] [Indexed: 12/24/2022] Open
Abstract
Background In addition to helminthic infections, elevated serum IgE levels were observed in many protozoal infections, while their contribution during immune response to these pathogens remained unclear. As IgE/antigen immune complexes (IgE-IC) bind to human cells through FcεRI or FcεRII/CD23 surface molecules, the present study aimed to identify which functional receptor may be involved in IgE-IC interaction with human macrophages, the major effector cell during parasite infection. Methodology/Principal Findings Human monocyte-derived macrophages were infected with Toxoplasma gondii before being incubated with IgE-IC. IgE receptors were then identified using appropriate blocking antibodies. The activation of cells and parasiticidal activity were evaluated by mediator quantification and direct counting of infected macrophages. RNAs were extracted and cell supernatants were also collected for their content in tumor necrosis factor (TNF)-α, interleukin-10 (IL-10) and nitrites. Sera from symptomatic infected patients were also tested for their content of IgE, IL-10 and nitrites, and compared to values found in healthy donors. Results showed that IgE-IC induced intracellular elimination of parasites by human macrophages. IgE-mediated effect was FcεRI-independent, but required cross-linking of surface FcεRII/CD23, cell activation and the generation of nitric oxide (NO). Although TNF-α was shown to be produced during cell activation, this cytokine had minor contribution in this phenomenon while endogenous and exogenous IL-10 down-regulated parasite killing. Inverse relationship was found between IL-10 and NO expression by infected human macrophages at both mRNA and mediator levels. The relationship between these in vitro data and in vivo levels of various factors in T. gondii infected patients supports the involvement of CD23 antigen and IL-10 expression in disease control. Conclusion Thus, IgE may be considered as immune mediator during antiprotozoal activity of human macrophages through its ability to trigger CD23 signaling. Increased cell activation by IgE-IC may also account for chronic inflammatory diseases observed in some patients.
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22
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Elo LL, Järvenpää H, Tuomela S, Raghav S, Ahlfors H, Laurila K, Gupta B, Lund RJ, Tahvanainen J, Hawkins RD, Oresic M, Lähdesmäki H, Rasool O, Rao KV, Aittokallio T, Lahesmaa R. Genome-wide profiling of interleukin-4 and STAT6 transcription factor regulation of human Th2 cell programming. Immunity 2010; 32:852-62. [PMID: 20620947 DOI: 10.1016/j.immuni.2010.06.011] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 04/20/2010] [Accepted: 05/26/2010] [Indexed: 01/30/2023]
Abstract
Dissecting the molecular mechanisms by which T helper (Th) cells differentiate to effector Th2 cells is important for understanding the pathogenesis of immune-mediated diseases, such as asthma and allergy. Because the STAT6 transcription factor is an upstream mediator required for interleukin-4 (IL-4)-induced Th2 cell differentiation, its targets include genes important for this process. Using primary human CD4(+) T cells, and by blocking STAT6 with RNAi, we identified a number of direct and indirect targets of STAT6 with ChIP sequencing. The integration of these data sets with detailed kinetics of IL-4-driven transcriptional changes showed that STAT6 was predominantly needed for the activation of transcription leading to the Th2 cell phenotype. This integrated genome-wide data on IL-4- and STAT6-mediated transcription provide a unique resource for studies on Th cell differentiation and, in particular, for designing interventions of human Th2 cell responses.
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Affiliation(s)
- Laura L Elo
- Biomathematics Research Group, Department of Mathematics, University of Turku, FI-20014 Turku, Finland
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Kühn H, O'Donnell VB. Inflammation and immune regulation by 12/15-lipoxygenases. Prog Lipid Res 2006; 45:334-56. [PMID: 16678271 DOI: 10.1016/j.plipres.2006.02.003] [Citation(s) in RCA: 289] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 01/19/2006] [Accepted: 02/06/2006] [Indexed: 12/22/2022]
Abstract
12/15-Lipoxygenases (12/15-LOX) are members of the LOX family, which are expressed in mammals by monocytes and macrophages following induction by the T helper type 2 cytokines, interleukins-4 and -13. They oxygenate free polyenoic fatty acids but also ester lipids and even complex lipid-protein assemblies such as biomembranes and lipoproteins. The primary oxidation products are either reduced by glutathione peroxidases to corresponding hydroxy derivatives or metabolized into secondary oxidized lipids including leukotrienes, lipoxins and hepoxilins, which act as lipid mediators. Examination of knockout and transgenic animals revealed important roles for 12/15-LOX in inflammatory diseases, including atherosclerosis, cancer, osteoporosis, angiotension II-dependent hypertension and diabetes. In vitro studies suggested 12/15-LOX products as coactivators of peroxisomal proliferator activating-receptors (PPAR), regulators of cytokine generation, and modulators of gene expression related to inflammation resolution. Despite much work in this area, the biochemical mechanisms by which 12/15-LOX regulates physiological and pathological immune cell function are not fully understood. This review will summarize the biochemistry and tissue expression of 12/15-LOX and will describe the current knowledge regarding its immunobiology and regulation of inflammation.
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Affiliation(s)
- Hartmut Kühn
- Institute of Biochemistry, Monbijoustrasse 2, University Medicine Berlin -- Charité, Germany
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Anderson SL, Rubin BY. Tocotrienols reverse IKAP and monoamine oxidase deficiencies in familial dysautonomia. Biochem Biophys Res Commun 2005; 336:150-6. [PMID: 16125677 DOI: 10.1016/j.bbrc.2005.08.054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 08/08/2005] [Indexed: 10/25/2022]
Abstract
Familial dysautonomia (FD), a recessive neurodegenerative disease, is caused by mutations in the IKBKAP gene that result in the production of nonfunctional IKAP protein. Manifestations of FD include autonomic crises characterized by hypertension, tachycardia, diaphoresis, and vomiting. Elevated plasma levels of norepinephrine (NE) and dopamine observed during autonomic crises and an exaggerated hypertensive response to low doses of NE prompted an examination of monoamine oxidase (MAO) levels, key isoenzymes responsible for degrading biogenic and dietary monoamines, in individuals with FD. Fetal tissue homozygous for the common FD-causing mutation and peripheral blood cells of individuals with FD have reduced MAO A mRNA levels. FD-derived cells, stimulated with tocotrienols or EGCG to produce increased levels of functional IKAP, express increased amounts of MAO A mRNA transcript and protein. Administration of tocotrienol to individuals with FD results in increased expression of both functional IKAP and MAO A transcripts in their peripheral blood cells. These findings provide new insight into the pathophysiology of FD and demonstrate the value of therapeutic approaches designed to elevate cellular levels of functional IKAP and MAO A.
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Affiliation(s)
- Sylvia L Anderson
- Laboratory for Familial Dysautonomia Research, Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA
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25
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Suguro T, Watanabe T, Kanome T, Kodate S, Hirano T, Miyazaki A, Adachi M. Serotonin acts as an up-regulator of acyl-coenzyme A:cholesterol acyltransferase-1 in human monocyte-macrophages. Atherosclerosis 2005; 186:275-81. [PMID: 16157345 DOI: 10.1016/j.atherosclerosis.2005.08.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2005] [Revised: 07/28/2005] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
Acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) converts intracellular free cholesterol into cholesterol ester for storage in lipid droplets and plays an important role in the formation of macrophage-derived foam cells in atherosclerotic lesions. Serotonin (5-HT), a potent vasoconstrictor that is released from activated platelets, increases uptake of oxidized low-density lipoprotein (LDL) by macrophages, leading to foam cell formation, and contributes to the development of atherosclerotic plaque. However, it is not yet known whether 5-HT affects ACAT-1 expression in human monocyte-macrophages as the molecular mechanism of enhanced foam cell formation by 5-HT remains unclear. We examined the effects of 5-HT on ACAT-1 expression during differentiation of cultured human monocytes into macrophages. Expression of ACAT-1 protein but not 5-HT2A receptor increased in a time-dependent manner. 5-HT increased ACAT activity in a concentration-dependent manner after 7 days in primary monocyte culture. Immunoblotting analysis showed that 5-HT at 10 microM increased ACAT-1 protein expression level by two-fold, and this effect was abolished completely by a 5-HT2A receptor antagonist (sarpogrelate), its major metabolite (M-1), a G protein inactivator (GDP-beta-S), a protein kinase C (PKC) inhibitor (rottlerin), a Src family inhibitor (PP2), or a mitogen-activated protein kinase (MAPK) kinase inhibitor (PD98059). Northern blotting analysis indicated that among the four ACAT-1 mRNA transcripts (2.8-, 3.6-, 4.3-, and 7.0-kb), the levels of the 2.8- and 3.6-kb transcripts were selectively up-regulated by approximately 1.7-fold by 5-HT (10 microM). The results of the present study suggested that 5-HT may play a crucial role in macrophage-derived foam cell formation by up-regulating ACAT-1 expression via the 5-HT2A receptor/G protein/c-Src/PKC/MAPK pathway, contributing to the progression of atherosclerotic plaque.
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Affiliation(s)
- Toshiaki Suguro
- First Department of Internal Medicine, Showa University School of Medicine, Tokyo 142-8666, Japan
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Chaitidis P, Kuhn H. Induction of 15-lipoxygenase-1 impairs expression of HIV-1 receptors CD4 and CXCR4 in monocytic cells. FEBS Lett 2005; 579:3691-4. [PMID: 15967444 DOI: 10.1016/j.febslet.2005.05.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 05/04/2005] [Accepted: 05/11/2005] [Indexed: 11/24/2022]
Abstract
The lipoxygenase pathway of immunocompetent cells has been related to HIV infection and interleukins-4 and -13 have been described as major regulators of this metabolic route. To explore whether 15-lipoxygenase1 expression might impact the responsiveness of monocytic cells for HIV we induced expression of this enzyme by two independent ways (stable transfection of U937 cells and culturing of blood monocytes in vitro in the presence of granulocyte/monocyte colony stimulating factor and interleukin 4) and assayed the cellular content of the two HIV-1 receptors CD4 and CXCR4 (CD184) by real time RT-PCR and fluorescence-activated cell sorting. Wild-type U937 cells express CD4 and CXCR4 at high levels and expression was not altered when the cells were transfected with control plasmids. In contrast, expression of these proteins was strongly reduced when the cells were stably transfected with 15-lipoxygenase1. Similar effects were observed when blood monocytes were cultured in the presence of granulocyte/monocyte colony stimulating factor and interleukin-4. Under these conditions strong overexpression of 15-lipoxygenase1 was paralleled by downregulation of CD4 and CXCR4. Since these surface proteins are essential for the binding of T-tropic HIV-1 strains expression of 15-lipoxygenase1 may confer resistance against HIV infection to monocytic cells.
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Affiliation(s)
- Pavlos Chaitidis
- Institute for Biochemistry, University Medicine Berlin-Charité, Monbijoustr. 2, D-10117 Berlin, Germany
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