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Planas AM. Role of microglia in stroke. Glia 2024; 72:1016-1053. [PMID: 38173414 DOI: 10.1002/glia.24501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/07/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
Microglia play key roles in the post-ischemic inflammatory response and damaged tissue removal reacting rapidly to the disturbances caused by ischemia and working to restore the lost homeostasis. However, the modified environment, encompassing ionic imbalances, disruption of crucial neuron-microglia interactions, spreading depolarization, and generation of danger signals from necrotic neurons, induce morphological and phenotypic shifts in microglia. This leads them to adopt a proinflammatory profile and heighten their phagocytic activity. From day three post-ischemia, macrophages infiltrate the necrotic core while microglia amass at the periphery. Further, inflammation prompts a metabolic shift favoring glycolysis, the pentose-phosphate shunt, and lipid synthesis. These shifts, combined with phagocytic lipid intake, drive lipid droplet biogenesis, fuel anabolism, and enable microglia proliferation. Proliferating microglia release trophic factors contributing to protection and repair. However, some microglia accumulate lipids persistently and transform into dysfunctional and potentially harmful foam cells. Studies also showed microglia that either display impaired apoptotic cell clearance, or eliminate synapses, viable neurons, or endothelial cells. Yet, it will be essential to elucidate the viability of engulfed cells, the features of the local environment, the extent of tissue damage, and the temporal sequence. Ischemia provides a rich variety of region- and injury-dependent stimuli for microglia, evolving with time and generating distinct microglia phenotypes including those exhibiting proinflammatory or dysfunctional traits and others showing pro-repair features. Accurate profiling of microglia phenotypes, alongside with a more precise understanding of the associated post-ischemic tissue conditions, is a necessary step to serve as the potential foundation for focused interventions in human stroke.
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Affiliation(s)
- Anna M Planas
- Cerebrovascular Research Laboratory, Department of Neuroscience and Experimental Therapeutics, Instituto de Investigaciones Biomédicas de Barcelona (IIBB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
- Cerebrovascular Diseases, Area of Clinical and Experimental Neuroscience, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)-Hospital Clínic, Barcelona, Spain
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2
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Lana D, Magni G, Landucci E, Wenk GL, Pellegrini-Giampietro DE, Giovannini MG. Phenomic Microglia Diversity as a Druggable Target in the Hippocampus in Neurodegenerative Diseases. Int J Mol Sci 2023; 24:13668. [PMID: 37761971 PMCID: PMC10531074 DOI: 10.3390/ijms241813668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
Phenomics, the complexity of microglia phenotypes and their related functions compels the continuous study of microglia in disease animal models to find druggable targets for neurodegenerative disorders. Activation of microglia was long considered detrimental for neuron survival, but more recently it has become apparent that the real scenario of microglia morphofunctional diversity is far more complex. In this review, we discuss the recent literature on the alterations in microglia phenomics in the hippocampus of animal models of normal brain aging, acute neuroinflammation, ischemia, and neurodegenerative disorders, such as AD. Microglia undergo phenomic changes consisting of transcriptional, functional, and morphological changes that transform them into cells with different properties and functions. The classical subdivision of microglia into M1 and M2, two different, all-or-nothing states is too simplistic, and does not correspond to the variety of phenotypes recently discovered in the brain. We will discuss the phenomic modifications of microglia focusing not only on the differences in microglia reactivity in the diverse models of neurodegenerative disorders, but also among different areas of the brain. For instance, in contiguous and highly interconnected regions of the rat hippocampus, microglia show a differential, finely regulated, and region-specific reactivity, demonstrating that microglia responses are not uniform, but vary significantly from area to area in response to insults. It is of great interest to verify whether the differences in microglia reactivity may explain the differential susceptibility of different brain areas to insults, and particularly the higher sensitivity of CA1 pyramidal neurons to inflammatory stimuli. Understanding the spatiotemporal heterogeneity of microglia phenomics in health and disease is of paramount importance to find new druggable targets for the development of novel microglia-targeted therapies in different CNS disorders. This will allow interventions in three different ways: (i) by suppressing the pro-inflammatory properties of microglia to limit the deleterious effect of their activation; (ii) by modulating microglia phenotypic change to favor anti-inflammatory properties; (iii) by influencing microglia priming early in the disease process.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Giada Magni
- Institute of Applied Physics “Nello Carrara”, National Research Council (IFAC-CNR), Via Madonna del Piano 10, 50019 Florence, Italy;
| | - Elisa Landucci
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Gary L. Wenk
- Department of Psychology, The Ohio State University, Columbus, OH 43210, USA;
| | - Domenico Edoardo Pellegrini-Giampietro
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
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3
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Fuchs AA, Balne PK, Giuliano EA, Sinha NR, Mohan RR. Evaluation of a novel combination of TRAM-34 and ascorbic acid for the treatment of corneal fibrosis in vivo. PLoS One 2022; 17:e0262046. [PMID: 35007294 PMCID: PMC8746773 DOI: 10.1371/journal.pone.0262046] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/15/2021] [Indexed: 01/05/2023] Open
Abstract
Corneal injury and aberrant wound healing commonly result in corneal fibrosis and subsequent vision loss. Intermediate-conductance calmodulin/calcium-activated K+ channels (KCa3.1) have been shown to promote fibrosis in non-ocular and ocular tissues via upregulation of transforming growth factor beta (TGFβ). TRAM-34 is a selective inhibitor of KCa3.1 and reduces fibrosis by downregulation of TGFβ-induced transdifferentiation of stromal fibroblasts to myofibroblasts. Ascorbic acid has been demonstrated to be effective in promoting corneal re-epithelialization and reduction of neovascularization via anti-VEGF and anti-MMP mechanisms. This study evaluates tolerability and efficacy of a novel combination of TRAM-34 (25μM) and ascorbic acid (10%) topical treatment for corneal fibrosis using an established in vivo rabbit model and conducting clinical eye examinations. Markers of corneal fibrosis were evaluated in all corneas at study endpoint via histopathology, immunofluorescence, and quantitative real-time PCR. The eyedrop treated eyes showed significantly improved clinical outcomes based on modified McDonald Shadduck scores, reduction of clinical haze on Fantes scores, and reduction of central corneal thickness (CCT). At cellular and molecular levels, eyedrop treatment also significantly reduced expression of alpha smooth muscle actin (α-SMA) mRNA and protein, collagen III mRNA, and fibronectin mRNA compared to non-treated eyes. Our study suggests that a tested new bimodal eyedrop is well tolerated and effectively reduces corneal fibrosis/haze in rabbits in vivo.
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Affiliation(s)
- Allison A. Fuchs
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Praveen K. Balne
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States of America
| | - Elizabeth A. Giuliano
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Nishant R. Sinha
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States of America
| | - Rajiv R. Mohan
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States of America
- Mason Eye Institute, School of Medicine, University of Missouri, Columbia, Missouri, United States of America
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4
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Daniel NH, Aravind A, Thakur P. Are ion channels potential therapeutic targets for Parkinson's disease? Neurotoxicology 2021; 87:243-257. [PMID: 34699791 DOI: 10.1016/j.neuro.2021.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/15/2021] [Accepted: 10/21/2021] [Indexed: 01/31/2023]
Abstract
Parkinson's disease (PD) is primarily associated with the progressive neurodegeneration of the dopaminergic neurons in the substantia nigra region of the brain. The resulting motor symptoms are managed with the help of dopamine replacement therapies. However, these therapeutics do not prevent the neurodegeneration underlying the disease and therefore lose their effectiveness in managing disease symptoms over time. Thus, there is an urgent need to develop newer therapeutics for the benefit of patients. The release of dopamine and the firing activity of substantia nigra neurons is regulated by several ion channels that act in concert. Dysregulations of these channels cause the aberrant movement of various ions in the intracellular milieu. This eventually leads to disruption of intracellular signalling cascades, alterations in cellular homeostasis, and bioenergetic deficits. Therefore, ion channels play a central role in driving the high vulnerability of dopaminergic neurons to degenerate during PD. Targeting ion channels offers an attractive mechanistic strategy to combat the process of neurodegeneration. In this review, we highlight the evidence pointing to the role of various ion channels in driving the PD processes. In addition, we also discuss the various drugs or compounds that target the ion channels and have shown neuroprotective potential in the in-vitro and in-vivo models of PD. We also discuss the current clinical status of various drugs targeting the ion channels in the context of PD.
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Affiliation(s)
- Neha Hanna Daniel
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Kerala, 695551, India
| | - Ananya Aravind
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Kerala, 695551, India
| | - Poonam Thakur
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Kerala, 695551, India.
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Seo CH, Cui HS, Kim JB. Altered K Ca3.1 expression following burn injury and the therapeutic potential of TRAM-34 in post-burn hypertrophic scar formation. Transl Res 2021; 236:133-146. [PMID: 33905948 DOI: 10.1016/j.trsl.2021.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/09/2021] [Accepted: 04/18/2021] [Indexed: 01/16/2023]
Abstract
Hypertrophic scars are the most common post-burn complications characterized by fibroblast proliferation and excessive extracellular matrix deposition. The intermediate-conductance Ca2+-activated K+ channel (KCa3.1) mediates fibroblast activation, resulting in several fibrotic diseases; however, this channel's role in the formation of post-burn hypertrophic skin scars remains unknown. Herein, we investigated the role of KCa3.1 and the therapeutic potential of TRAM-34, a selective inhibitor of KCa3.1, in hypertrophic skin scar formation following burn injury. Cytosolic Ca2+ levels, the expression of KCa3.1 and hypertrophic markers, and the proliferation of skin fibroblasts obtained directly from patients with third-degree burns who consequently developed post-burn hypertrophic scars were assessed. The anti-fibrotic effect of KCa3.1 inhibition by TRAM-34 was evaluated in vitro (fibroblasts) and in vivo (mouse burn models). Fibroblasts from burn wounds exhibited remarkably higher levels of cytosolic Ca2+ than normal cells. KCa3.1 expression was markedly higher in the membrane fraction but lower in the cytosolic fraction of burn wound fibroblasts than in normal cells. Selective inhibition of KCa3.1 by TRAM-34 markedly reduced not only the proliferation of burn wound fibroblasts but also the expression of hypertrophic markers in these cells. Anti-scarring molecular, histological, and visual effects of TRAM-34 were confirmed in murine burn models. Altered subcellular expression of KCa3.1 is a novel mechanism underlying the cellular response to burn injury. Our results suggest that selective inhibition of KCa3.1 by TRAM-34 has therapeutic potential against post-burn hypertrophic scar formation.
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Affiliation(s)
- Cheong Hoon Seo
- Department of Rehabilitation Medicine, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Hui Song Cui
- Burn Institute, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - June-Bum Kim
- Department of Pediatrics, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
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Lu J, Dou F, Yu Z. The potassium channel KCa3.1 represents a valid pharmacological target for microgliosis-induced neuronal impairment in a mouse model of Parkinson's disease. J Neuroinflammation 2019; 16:273. [PMID: 31878950 PMCID: PMC6931251 DOI: 10.1186/s12974-019-1682-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 12/17/2019] [Indexed: 12/11/2022] Open
Abstract
Background Recent studies described a critical role for microglia in Parkinson’s disease (PD), where these central nerve system resident immune cells participate in the neuroinflammatory microenvironment that contributes to dopaminergic neurons loss in the substantia nigra. Understanding the phenotype switch of microgliosis in PD could help to identify the molecular mechanism which could attenuate or delay the progressive decline in motor function. KCa3.1 has been reported to regulate the “pro-inflammatory” phenotype switch of microglia in neurodegenerative pathological conditions. Methods We here investigated the effects of gene deletion or pharmacological blockade of KCa3.1 activity in wild-type or KCa3.1−/− mice after treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a mouse model of PD. MPTP-induced PD mouse model was subjected to the rotarod test to evaluate the locomotor ability. Glia activation and neuron loss were measured by immunostaining. Fluo-4 AM was used to measure cytosolic Ca2+ level in 1-methyl-4-phenylpyridinium (MPP+)-induced microgliosis in vitro. Results We report that treatment of MPTP-induced PD mouse model with gene deletion or pharmacological blockade of KCa3.1 with senicapoc improves the locomotor ability and the tyrosine hydroxylase (TH)-positive neuron number and attenuates the microgliosis and neuroinflammation in the substantia nigra pars compacta (SNpc). KCa3.1 involves in store-operated Ca2+ entry-induced Ca2+ overload and endoplasmic reticulum stress via the protein kinase B (AKT) signaling pathway during microgliosis. Gene deletion or blockade of KCa3.1 restored AKT/mammalian target of rapamycin (mTOR) signaling both in vivo and in vitro. Conclusions Taken together, these results demonstrate a key role for KCa3.1 in driving a pro-inflammatory microglia phenotype in PD.
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Affiliation(s)
- Jia Lu
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China
| | - Fangfang Dou
- Basic Research Department, Shanghai Geriatric Institute of Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200031, China
| | - Zhihua Yu
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, 200025, China.
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7
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Biber K, Bhattacharya A, Campbell BM, Piro JR, Rohe M, Staal RGW, Talanian RV, Möller T. Microglial Drug Targets in AD: Opportunities and Challenges in Drug Discovery and Development. Front Pharmacol 2019; 10:840. [PMID: 31507408 PMCID: PMC6716448 DOI: 10.3389/fphar.2019.00840] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 07/01/2019] [Indexed: 12/20/2022] Open
Abstract
Alzheimer’s disease (AD) is a large and increasing unmet medical need with no disease-modifying treatment currently available. Genetic evidence from genome-wide association studies (GWASs) and gene network analysis has clearly revealed a key role of the innate immune system in the brain, of which microglia are the most important element. Single-nucleotide polymorphisms (SNPs) in genes predominantly expressed in microglia have been associated with altered risk of developing AD. Furthermore, microglia-specific pathways are affected on the messenger RNA (mRNA) expression level in post-mortem AD tissue and in mouse models of AD. Together these findings have increased the interest in microglia biology, and numerous scientific reports have proposed microglial molecules and pathways as drug targets for AD. Target identification and validation are generally the first steps in drug discovery. Both target validation and drug lead identification for central nervous system (CNS) targets and diseases entail additional significant obstacles compared to peripheral targets and diseases. This makes CNS drug discovery, even with well-validated targets, challenging. In this article, we will illustrate the special challenges of AD drug discovery by discussing the viability/practicality of possible microglia drug targets including cluster of differentiation 33 (CD33), KCa3.1, kynurenines, ionotropic P2 receptor 7 (P2X7), programmed death-1 (PD-1), Toll-like receptors (TLRs), and triggering receptor expressed in myeloid cells 2 (TREM2).
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Affiliation(s)
- Knut Biber
- AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Ludwigshafen, Germany
| | | | | | - Justin R Piro
- AbbVie Foundational Neuroscience Center, Cambridge, MA, United States
| | - Michael Rohe
- AbbVie Deutschland GmbH & Co. KG, Neuroscience Research, Ludwigshafen, Germany
| | | | - Robert V Talanian
- AbbVie Foundational Neuroscience Center, Cambridge, MA, United States
| | - Thomas Möller
- AbbVie Foundational Neuroscience Center, Cambridge, MA, United States
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8
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Brown BM, Shim H, Christophersen P, Wulff H. Pharmacology of Small- and Intermediate-Conductance Calcium-Activated Potassium Channels. Annu Rev Pharmacol Toxicol 2019; 60:219-240. [PMID: 31337271 DOI: 10.1146/annurev-pharmtox-010919-023420] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The three small-conductance calcium-activated potassium (KCa2) channels and the related intermediate-conductance KCa3.1 channel are voltage-independent K+ channels that mediate calcium-induced membrane hyperpolarization. When intracellular calcium increases in the channel vicinity, it calcifies the flexible N lobe of the channel-bound calmodulin, which then swings over to the S4-S5 linker and opens the channel. KCa2 and KCa3.1 channels are highly druggable and offer multiple binding sites for venom peptides and small-molecule blockers as well as for positive- and negative-gating modulators. In this review, we briefly summarize the physiological role of KCa channels and then discuss the pharmacophores and the mechanism of action of the most commonly used peptidic and small-molecule KCa2 and KCa3.1 modulators. Finally, we describe the progress that has been made in advancing KCa3.1 blockers and KCa2.2 negative- and positive-gating modulators toward the clinic for neurological and cardiovascular diseases and discuss the remaining challenges.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | - Heesung Shim
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | | | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California 95616, USA;
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Abstract
The cellular mechanisms governing the expression, regulation, and function of sleep are not entirely understood. The traditional view is that these mechanisms are neuronal. An alternative view is that glial brain cells may play important roles in these processes. Their ubiquity in the central nervous system makes them well positioned to modulate neuronal circuits that gate sleep and wake. Their ability to respond to chemical neuronal signals suggests that they form feedback loops with neurons that may globally regulate neuronal activity. Their potential role in detoxifying the brain, regulating neuronal metabolism, and promoting synaptic plasticity raises the intriguing possibility that glia mediate important functions ascribed to sleep.
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Affiliation(s)
- Marcos G Frank
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University Spokane, Spokane, WA, USA.
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10
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Brown BM, Pressley B, Wulff H. KCa3.1 Channel Modulators as Potential Therapeutic Compounds for Glioblastoma. Curr Neuropharmacol 2018; 16:618-626. [PMID: 28676010 PMCID: PMC5997873 DOI: 10.2174/1570159x15666170630164226] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/31/2022] Open
Abstract
Background The intermediate-conductance Ca2+-activated K+ channel KCa3.1 is widely expressed in cells of the immune system such as T- and B-lymphocytes, mast cells, macrophages and microglia, but also found in dedifferentiated vascular smooth muscle cells, fibroblasts and many cancer cells including pancreatic, prostate, leukemia and glioblastoma. In all these cell types KCa3.1 plays an important role in cellular activation, migration and proliferation by regulating membrane potential and Ca2+ signaling. Methods and Results KCa3.1 therefore constitutes an attractive therapeutic target for diseases involving excessive proliferation or activation of one more of these cell types and researchers both in academia and in the pharmaceutical industry have developed several potent and selective small molecule inhibitors of KCa3.1. This article will briefly review the available compounds (TRAM-34, senicapoc, NS6180), their binding sites and mechanisms of action, and then discuss the potential usefulness of these compounds for the treatment of brain tumors based on their brain penetration and their efficacy in reducing microglia activation in animal models of ischemic stroke and Alzheimer’s disease. Conclusion Senicapoc, which has previously been in Phase III clinical trials, would be available for repurposing, and could be used to quickly translate findings made with other KCa3.1 blocking tool compounds into clinical trials.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Brandon Pressley
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
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11
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Sifat AE, Vaidya B, Villalba H, Albekairi TH, Abbruscato TJ. Neurovascular unit transport responses to ischemia and common coexisting conditions: smoking and diabetes. Am J Physiol Cell Physiol 2018; 316:C2-C15. [PMID: 30207783 DOI: 10.1152/ajpcell.00187.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Transporters at the neurovascular unit (NVU) are vital for the regulation of normal brain physiology via ion, water, and nutrients movement. In ischemic stroke, the reduction of cerebral blood flow causes several complex pathophysiological changes in the brain, one of which includes alterations of the NVU transporters, which can exacerbate stroke outcome by increased brain edema (by altering ion, water, and glutamate transporters), altered energy metabolism (by altering glucose transporters), and enhanced drug toxicity (by altering efflux transporters). Smoking and diabetes are common risk factors as well as coexisting conditions in ischemic stroke that are also reported to change the expression and function of NVU transporters. Coexistence of these conditions could cause an additive effect in terms of the alterations of brain transporters that might lead to worsened ischemic stroke prognosis and recovery. In this review, we have discussed the effects of ischemic stroke, smoking, and diabetes on some essential NVU transporters and how the simultaneous presence of these conditions can affect the clinical outcome after an ischemic episode. Further scientific investigations are required to elucidate changes in NVU transport in cerebral ischemia, which can lead to better, personalized therapeutic interventions tailor-made for these comorbid conditions.
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Affiliation(s)
- Ali E Sifat
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center , Amarillo, Texas
| | - Bhuvaneshwar Vaidya
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center , Amarillo, Texas
| | - Heidi Villalba
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center , Amarillo, Texas
| | - Thamer H Albekairi
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center , Amarillo, Texas
| | - Thomas J Abbruscato
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center , Amarillo, Texas
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12
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Fumagalli M, Lombardi M, Gressens P, Verderio C. How to reprogram microglia toward beneficial functions. Glia 2018; 66:2531-2549. [PMID: 30195261 PMCID: PMC6585737 DOI: 10.1002/glia.23484] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/13/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022]
Abstract
Microglia, brain cells of nonneural origin, orchestrate the inflammatory response to diverse insults, including hypoxia/ischemia or maternal/fetal infection in the perinatal brain. Experimental studies have demonstrated the capacity of microglia to recognize pathogens or damaged cells activating a cytotoxic response that can exacerbate brain damage. However, microglia display an enormous plasticity in their responses to injury and may also promote resolution stages of inflammation and tissue regeneration. Despite the critical role of microglia in brain pathologies, the cellular mechanisms that govern the diverse phenotypes of microglia are just beginning to be defined. Here we review emerging strategies to drive microglia toward beneficial functions, selectively reporting the studies which provide insights into molecular mechanisms underlying the phenotypic switch. A variety of approaches have been proposed which rely on microglia treatment with pharmacological agents, cytokines, lipid messengers, or microRNAs, as well on nutritional approaches or therapies with immunomodulatory cells. Analysis of the molecular mechanisms relevant for microglia reprogramming toward pro‐regenerative functions points to a central role of energy metabolism in shaping microglial functions. Manipulation of metabolic pathways may thus provide new therapeutic opportunities to prevent the deleterious effects of inflammatory microglia and to control excessive inflammation in brain disorders.
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Affiliation(s)
- Marta Fumagalli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, via Balzaretti, 9 -20133, Milan, Italy
| | | | - Pierre Gressens
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 1141 Paris, France.,Centre for the Developing Brain, Department of Perinatal Health and Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, SE1 7EH, United Kingdom
| | - Claudia Verderio
- IRCCS Humanitas, via Manzoni 56, 20089, Rozzano, Italy.,CNR Institute of Neuroscience, via Vanvitelli 32, 20129 Milan, Italy
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13
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Xie H, Lu J, Zhu Y, Meng X, Wang R. The KCa3.1 blocker TRAM-34 inhibits proliferation of fibroblasts in paraquat-induced pulmonary fibrosis. Toxicol Lett 2018; 295:408-415. [PMID: 30036685 DOI: 10.1016/j.toxlet.2018.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 07/15/2018] [Accepted: 07/19/2018] [Indexed: 01/30/2023]
Abstract
KCa3.1, a Ca2+-activated K+ channel, plays an important role in modulating calcium signaling and maintaining membrane potential during cell activation. It has been reported to promote fibroblast function in many fibrotic diseases. However, the role of KCa3.1 in the pathophysiology of pulmonary fibrosis after paraquat (PQ) poisoning has not been studied. A rat model of PQ poisoning was used. After treatment with TRAM-34, which is a highly selective KCa3.1 blocker, the expression of KCa3.1, TGF-β1 and α-SMA were evaluated via Western blot, histology and other assays. Bromodeoxyuridine (BrdU) marking and MTT assay were used to measure primary rat pulmonary fibroblast proliferation. The results showed that KCa3.1 expression was elevated after PQ poisoning. Blockade of KCa3.1 alleviated PQ-induced pulmonary inflammation and fibrosis. Blockade of KCa3.1 also attenuated the level of collagen I and α-SMA and the proliferation of fibroblasts. However, TGF-β1 expression remained unaffected by blockade of KCa3.1 in rat lung tissues after PQ poisoning. The present study suggests that KCa3.1 expression increased and might promote pulmonary fibroblast proliferation in PQ-induced pulmonary fibrosis. In addition, we confirmed that TRAM-34 attenuates proliferation and collagen secretion of fibroblasts. Our findings indicated that TRAM-34 might inhibit PQ-induced proliferation of pulmonary fibroblasts and prevent progression of lung fibrosis.
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Affiliation(s)
- Hui Xie
- Department of Critical Care Medicine, Shanghai General Hospital of Nanjing Medical University, Shanghai 201620, China
| | - Jian Lu
- Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 201620, China
| | - Yong Zhu
- Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 201620, China
| | - Xiaoxiao Meng
- Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 201620, China
| | - Ruilan Wang
- Department of Critical Care Medicine, Shanghai General Hospital of Nanjing Medical University, Shanghai 201620, China.
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14
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Lively S, Lam D, Wong R, Schlichter LC. Comparing Effects of Transforming Growth Factor β1 on Microglia From Rat and Mouse: Transcriptional Profiles and Potassium Channels. Front Cell Neurosci 2018; 12:115. [PMID: 29780305 PMCID: PMC5946019 DOI: 10.3389/fncel.2018.00115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/11/2018] [Indexed: 12/02/2022] Open
Abstract
The cytokine, transforming growth factor β1 (TGFβ1), is up-regulated after central nervous system (CNS) injuries or diseases involving microglial activation, and it has been proposed as a therapeutic agent for treating neuroinflammation. Microglia can produce and respond to TGFβ1. While rats and mice are commonly used for studying neuroinflammation, very few reports directly compare them. Such studies are important for improving pre-clinical studies and furthering translational progress in developing therapeutic interventions. After intracerebral hemorrhage (ICH) in the rat striatum, the TGFβ1 receptor was highly expressed on microglia/macrophages within the hematoma. We recently found species similarities and differences in response to either a pro-inflammatory (interferon-γ, IFN-γ, +tumor necrosis factor, TNF-α) or anti-inflammatory interleukin-4 (IL-4) stimulus. Here, we assessed whether rat and mouse microglia differ in their responses to TGFβ1. Microglia were isolated from Sprague-Dawley rats and C57BL/6 mice and treated with TGFβ1. We quantified changes in expression of >50 genes, in their morphology, proliferation, apoptosis and in three potassium channels that are considered therapeutic targets. Many inflammatory mediators, immune receptors and modulators showed species similarities, but notable differences included that, for some genes, only one species responded (e.g., Il4r, Il10, Tgfbr2, colony-stimulating factor receptor (Csf1r), Itgam, suppressor of cytokine signaling 1 (Socs1), toll-like receptors 4 (Tlr4), P2rx7, P2ry12), and opposite responses were seen for others (Tgfb1, Myc, Ifngr1). In rat only, TGFβ1 affected microglial morphology and proliferation, but there was no apoptosis in either species. In both species, TGFβ1 dramatically increased Kv1.3 channel expression and current (no effects on Kir2.1). KCa3.1 showed opposite species responses: the current was low in unstimulated rat microglia and greatly increased by TGFβ1 but higher in control mouse cells and decreased by TGFβ1. Finally, we compared TGFβ1 and IL10 (often considered similar anti-inflammatory stimuli) and found many different responses in both species. Overall, the numerous species differences should be considered when characterizing neuroinflammation and microglial activation in vitro and in vivo, and when targeting potassium channels.
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Affiliation(s)
- Starlee Lively
- Krembil Research Institute, Genes and Development Division, University Health Network, Toronto, ON, Canada
| | - Doris Lam
- Krembil Research Institute, Genes and Development Division, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Raymond Wong
- Krembil Research Institute, Genes and Development Division, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Lyanne C Schlichter
- Krembil Research Institute, Genes and Development Division, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
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15
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Lu R, Flauaus C, Kennel L, Petersen J, Drees O, Kallenborn-Gerhardt W, Ruth P, Lukowski R, Schmidtko A. K Ca3.1 channels modulate the processing of noxious chemical stimuli in mice. Neuropharmacology 2017; 125:386-395. [PMID: 28823609 DOI: 10.1016/j.neuropharm.2017.08.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/26/2017] [Accepted: 08/16/2017] [Indexed: 12/19/2022]
Abstract
Intermediate conductance calcium-activated potassium channels (KCa3.1) have been recently implicated in pain processing. However, the functional role and localization of KCa3.1 in the nociceptive system are largely unknown. We here characterized the behavior of mice lacking KCa3.1 (KCa3.1-/-) in various pain models and analyzed the expression pattern of KCa3.1 in dorsal root ganglia (DRG) and the spinal cord. KCa3.1-/- mice demonstrated normal behavioral responses in models of acute nociceptive, persistent inflammatory, and persistent neuropathic pain. However, their behavioral responses to noxious chemical stimuli such as formalin and capsaicin were increased. Accordingly, formalin-induced nociceptive behavior was increased in wild-type mice after administration of the KCa3.1 inhibitor TRAM-34. In situ hybridization experiments detected KCa3.1 in most DRG satellite glial cells, in a minority of DRG neurons, and in ependymal cells lining the central canal of the spinal cord. Together, our data point to a specific inhibitory role of KCa3.1 for the processing of noxious chemical stimuli.
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Affiliation(s)
- Ruirui Lu
- Pharmakologisches Institut für Naturwissenschaftler, Goethe-Universität, Fachbereich Biochemie, Chemie und Pharmazie, 60438 Frankfurt am Main, Germany; Institut für Pharmakologie und Toxikologie, Universität Witten/Herdecke, ZBAF, 58453 Witten, Germany.
| | - Cathrin Flauaus
- Pharmakologisches Institut für Naturwissenschaftler, Goethe-Universität, Fachbereich Biochemie, Chemie und Pharmazie, 60438 Frankfurt am Main, Germany
| | - Lea Kennel
- Pharmakologisches Institut für Naturwissenschaftler, Goethe-Universität, Fachbereich Biochemie, Chemie und Pharmazie, 60438 Frankfurt am Main, Germany
| | - Jonas Petersen
- Pharmakologisches Institut für Naturwissenschaftler, Goethe-Universität, Fachbereich Biochemie, Chemie und Pharmazie, 60438 Frankfurt am Main, Germany; Institut für Pharmakologie und Toxikologie, Universität Witten/Herdecke, ZBAF, 58453 Witten, Germany
| | - Oliver Drees
- Institut für Pharmakologie und Toxikologie, Universität Witten/Herdecke, ZBAF, 58453 Witten, Germany
| | - Wiebke Kallenborn-Gerhardt
- Pharmakologisches Institut für Naturwissenschaftler, Goethe-Universität, Fachbereich Biochemie, Chemie und Pharmazie, 60438 Frankfurt am Main, Germany
| | - Peter Ruth
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Universität Tübingen, 72076 Tübingen, Germany
| | - Robert Lukowski
- Pharmakologie, Toxikologie und Klinische Pharmazie, Institut für Pharmazie, Universität Tübingen, 72076 Tübingen, Germany
| | - Achim Schmidtko
- Pharmakologisches Institut für Naturwissenschaftler, Goethe-Universität, Fachbereich Biochemie, Chemie und Pharmazie, 60438 Frankfurt am Main, Germany; Institut für Pharmakologie und Toxikologie, Universität Witten/Herdecke, ZBAF, 58453 Witten, Germany
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16
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Cole KLH, Early JJ, Lyons DA. Drug discovery for remyelination and treatment of MS. Glia 2017; 65:1565-1589. [PMID: 28618073 DOI: 10.1002/glia.23166] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/20/2017] [Accepted: 04/24/2017] [Indexed: 12/19/2022]
Abstract
Glia constitute the majority of the cells in our nervous system, yet there are currently no drugs that target glia for the treatment of disease. Given ongoing discoveries of the many roles of glia in numerous diseases of the nervous system, this is likely to change in years to come. Here we focus on the possibility that targeting the oligodendrocyte lineage to promote regeneration of myelin (remyelination) represents a therapeutic strategy for the treatment of the demyelinating disease multiple sclerosis, MS. We discuss how hypothesis driven studies have identified multiple targets and pathways that can be manipulated to promote remyelination in vivo, and how this work has led to the first ever remyelination clinical trials. We also highlight how recent chemical discovery screens have identified a host of small molecule compounds that promote oligodendrocyte differentiation in vitro. Some of these compounds have also been shown to promote myelin regeneration in vivo, with one already being trialled in humans. Promoting oligodendrocyte differentiation and remyelination represents just one potential strategy for the treatment of MS. The pathology of MS is complex, and its complete amelioration may require targeting multiple biological processes in parallel. Therefore, we present an overview of new technologies and models for phenotypic analyses and screening that can be exploited to study complex cell-cell interactions in in vitro and in vivo systems. Such technological platforms will provide insight into fundamental mechanisms and increase capacities for drug-discovery of relevance to glia and currently intractable disorders of the CNS.
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Affiliation(s)
- Katy L H Cole
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
| | - Jason J Early
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
| | - David A Lyons
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, United Kingdom
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17
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Shibata M, Suzuki N. Exploring the role of microglia in cortical spreading depression in neurological disease. J Cereb Blood Flow Metab 2017; 37:1182-1191. [PMID: 28155572 PMCID: PMC5414895 DOI: 10.1177/0271678x17690537] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Microglia play a pivotal role in innate immunity in the brain. During development, they mature from myeloerythroid progenitor cells in the yolk sac and colonize the brain to establish a resident population of tissue macrophages. In the postnatal brain, they exert phagocytosis and induce inflammatory response against invading pathogens. Microglia also act as guardians of brain homeostasis by surveying the microenvironment using motile processes. Cortical spreading depression (CSD) is a slowly propagating (2-5 mm/min) wave of rapid, near-complete depolarization of neurons and astrocytes followed by a period of electrical suppression of a distinct population of cortical neurons. Not only has CSD been implicated in brain migraine aura, but CSD-like events have also been detected in stroke and traumatic injury. CSD causes a considerable perturbation of the ionic environment in the brain, which may be readily detected by microglia. Although CSD is known to activate microglia, the role of microglial activation in CSD-related neurological disorders remains poorly understood. In this article, we first provide an overview of microglial development and the multiple functions of microglia. Then, we review existing data on the relationship between microglia and CSD and discuss the relevance of CSD-induced microglial activation in neurological disease.
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Affiliation(s)
- Mamoru Shibata
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
| | - Norihiro Suzuki
- Department of Neurology, Keio University School of Medicine, Tokyo, Japan
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18
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Staal RGW, Weinstein JR, Nattini M, Cajina M, Chandresana G, Möller T. Senicapoc: Repurposing a Drug to Target Microglia K Ca3.1 in Stroke. Neurochem Res 2017; 42:2639-2645. [PMID: 28364331 DOI: 10.1007/s11064-017-2223-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
Stroke is the leading cause of serious long-term disability and the fifth leading cause of death in the United States. Treatment options for stroke are few in number and limited in efficacy. Neuroinflammation mediated by microglia and infiltrating peripheral immune cells is a major component of stroke pathophysiology. Interfering with the inflammation cascade after stroke holds the promise to modulate stroke outcome. The calcium activated potassium channel KCa3.1 is expressed selectively in the injured CNS by microglia. KCa3.1 function has been implicated in pro-inflammatory activation of microglia and there is recent literature suggesting that this channel is important in the pathophysiology of ischemia/reperfusion (stroke) related brain injury. Here we describe the potential of repurposing Senicapoc, a KCa3.1 inhibitor, to intervene in the inflammation cascade that follows ischemia/reperfusion.
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Affiliation(s)
- Roland G W Staal
- Alentis Pharma LLC, 72 Hillside Avenue, Metuchen, NJ, 08840, USA
| | - Jonathan R Weinstein
- Department of Neurology, School of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Megan Nattini
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ, 07652, USA
| | - Manuel Cajina
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ, 07652, USA
| | - Gamini Chandresana
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ, 07652, USA
| | - Thomas Möller
- Abbvie, Foundational Neuroscience Center, Cambridge, MA, 02139, USA.
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19
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Bhatia HS, Roelofs N, Muñoz E, Fiebich BL. Alleviation of Microglial Activation Induced by p38 MAPK/MK2/PGE 2 Axis by Capsaicin: Potential Involvement of other than TRPV1 Mechanism/s. Sci Rep 2017; 7:116. [PMID: 28273917 PMCID: PMC5428011 DOI: 10.1038/s41598-017-00225-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/14/2017] [Indexed: 12/13/2022] Open
Abstract
Exaggerated inflammatory responses in microglia represent one of the major risk factors for various central nervous system’s (CNS) associated pathologies. Release of excessive inflammatory mediators such as prostaglandins and cytokines are the hallmark of hyper-activated microglia. Here we have investigated the hitherto unknown effects of capsaicin (cap) - a transient receptor potential vanilloid 1 (TRPV1) agonist- in murine primary microglia, organotypic hippocampal slice cultures (OHSCs) and human primary monocytes. Results demonstrate that cap (0.1–25 µM) significantly (p < 0.05) inhibited the release of prostaglandin E2 (PGE2), 8-iso-PGF2α, and differentially regulated the levels of cytokines (TNF-α, IL-6 & IL-1β). Pharmacological blockade (via capsazepine & SB366791) and genetic deficiency of TRPV1 (TRPV1−/−) did not prevent cap-mediated suppression of PGE2 in activated microglia and OHSCs. Inhibition of PGE2 was partially dependent on the reduced levels of PGE2 synthesising enzymes, COX-2 and mPGES-1. To evaluate potential molecular targets, we discovered that cap significantly suppressed the activation of p38 MAPK and MAPKAPK2 (MK2). Altogether, we demonstrate that cap alleviates excessive inflammatory events by targeting the PGE2 pathway in in vitro and ex vivo immune cell models. These findings have broad relevance in understanding and paving new avenues for ongoing TRPV1 based drug therapies in neuroinflammatory-associated diseases.
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Affiliation(s)
- Harsharan S Bhatia
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, D-79104, Freiburg, Germany. .,VivaCell Biotechnology GmbH, Ferdinand-Porsche-Strasse 5, D-79211, Denzlingen, Germany.
| | - Nora Roelofs
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, D-79104, Freiburg, Germany
| | - Eduardo Muñoz
- Maimonides Biomedical Research Institute of Córdoba, Reina Sofía University Hospital, Department of Cell Biology, Physiology and Immunology, University of Córdoba, Avda Menéndez Pidal s/n., 14004, Córdoba, Spain.,VivaCell Biotechnology España, Parque Científico Tecnológico Rabanales 21, 14014, Córdoba, Spain
| | - Bernd L Fiebich
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, D-79104, Freiburg, Germany.,VivaCell Biotechnology GmbH, Ferdinand-Porsche-Strasse 5, D-79211, Denzlingen, Germany
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20
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Nguyen HM, Blomster LV, Christophersen P, Wulff H. Potassium channel expression and function in microglia: Plasticity and possible species variations. Channels (Austin) 2017; 11:305-315. [PMID: 28277939 DOI: 10.1080/19336950.2017.1300738] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Potassium channels play important roles in microglia functions and thus constitute potential targets for the treatment of neurodegenerative diseases like Alzheimer, Parkinson and stroke. However, uncertainty still prevails as to which potassium channels are expressed and at what levels in different species, how the expression pattern changes upon activation with M1 or M2 polarizing stimuli compared with more complex exposure paradigms, and - most importantly - how these findings relate to the in vivo situation. In this mini-review we discuss the functional potassium channel expression pattern in cultured neonatal mouse microglia in the light of data obtained previously from animal disease models and immunohistochemical studies and compare it with a recent study of adult human microglia isolated from epilepsy patients. Overall, microglial potassium channel expression is very plastic and possibly shows species differences and therefore should be studied carefully in each disease setting and respective animal models.
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Affiliation(s)
- Hai M Nguyen
- a Department of Pharmacology , University of California , Davis, Davis , CA , USA
| | | | | | - Heike Wulff
- a Department of Pharmacology , University of California , Davis, Davis , CA , USA
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21
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Augustynek B, Kunz WS, Szewczyk A. Guide to the Pharmacology of Mitochondrial Potassium Channels. Handb Exp Pharmacol 2017; 240:103-127. [PMID: 27838853 DOI: 10.1007/164_2016_79] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This chapter provides a critical overview of the available literature on the pharmacology of mitochondrial potassium channels. In the first part, the reader is introduced to the topic, and eight known protein contributors to the potassium permeability of the inner mitochondrial membrane are presented. The main part of this chapter describes the basic characteristics of each channel type mentioned in the introduction. However, the most important and valuable information included in this chapter concerns the pharmacology of mitochondrial potassium channels. Several available channel modulators are critically evaluated and rated by suitability for research use. The last figure of this chapter shows the results of this evaluation at a glance. Thus, this chapter can be very useful for beginners in this field. It is intended to be a time- and resource-saving guide for those searching for proper modulators of mitochondrial potassium channels.
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Affiliation(s)
- Bartłomiej Augustynek
- Laboratory of Intracellular Ion Channels, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Wolfram S Kunz
- Department of Epileptology, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093, Warsaw, Poland.
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22
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Staal RGW, Khayrullina T, Zhang H, Davis S, Fallon SM, Cajina M, Nattini ME, Hu A, Zhou H, Poda SB, Zorn S, Chandrasena G, Dale E, Cambpell B, Biilmann Rønn LC, Munro G, Mӧller T. Inhibition of the potassium channel K Ca3.1 by senicapoc reverses tactile allodynia in rats with peripheral nerve injury. Eur J Pharmacol 2016; 795:1-7. [PMID: 27876619 DOI: 10.1016/j.ejphar.2016.11.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 11/18/2016] [Accepted: 11/18/2016] [Indexed: 01/16/2023]
Abstract
Neuropathic pain is a debilitating, chronic condition with a significant unmet need for effective treatment options. Recent studies have demonstrated that in addition to neurons, non-neuronal cells such as microglia contribute to the initiation and maintenance of allodynia in rodent models of neuropathic pain. The Ca2+- activated K+ channel, KCa3.1 is critical for the activation of immune cells, including the CNS-resident microglia. In order to evaluate the role of KCa3.1 in the maintenance of mechanical allodynia following peripheral nerve injury, we used senicapoc, a stable and highly potent KCa3.1 inhibitor. In primary cultured microglia, senicapoc inhibited microglial nitric oxide and IL-1β release. In vivo, senicapoc showed high CNS penetrance and when administered to rats with peripheral nerve injury, it significantly reversed tactile allodynia similar to the standard of care, gabapentin. In contrast to gabapentin, senicapoc achieved efficacy without any overt impact on locomotor activity. Together, the data demonstrate that the KCa3.1 inhibitor senicapoc is effective at reducing mechanical hypersensitivity in a rodent model of peripheral nerve injury.
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Affiliation(s)
- Roland G W Staal
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA.
| | - Tanzilya Khayrullina
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
| | - Hong Zhang
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
| | - Scott Davis
- Psychogenics Inc., 765 Old Saw Mill River Rd #104, Tarrytown, NY 10591, USA
| | - Shaun M Fallon
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
| | - Manuel Cajina
- Molecular Pharmacology, Bioanalysis & Operations, Lundbeck Research USA Inc., 215 College Road, Paramus, NJ 07652, USA
| | - Megan E Nattini
- Molecular Pharmacology, Bioanalysis & Operations, Lundbeck Research USA Inc., 215 College Road, Paramus, NJ 07652, USA
| | - Andrew Hu
- Psychogenics Inc., 765 Old Saw Mill River Rd #104, Tarrytown, NY 10591, USA
| | - Hua Zhou
- Molecular Pharmacology, Bioanalysis & Operations, Lundbeck Research USA Inc., 215 College Road, Paramus, NJ 07652, USA
| | - Suresh Babu Poda
- Molecular Pharmacology, Bioanalysis & Operations, Lundbeck Research USA Inc., 215 College Road, Paramus, NJ 07652, USA
| | - Stevin Zorn
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
| | - Gamini Chandrasena
- Molecular Pharmacology, Bioanalysis & Operations, Lundbeck Research USA Inc., 215 College Road, Paramus, NJ 07652, USA
| | - Elena Dale
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
| | - Brian Cambpell
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
| | | | - Gordon Munro
- Neurodegeneration Disease Biology Unit, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
| | - Thomas Mӧller
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Inc., 215 College Rd, Paramus, NJ 07652, USA
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23
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Nguyen HM, Grössinger EM, Horiuchi M, Davis KW, Jin LW, Maezawa I, Wulff H. Differential Kv1.3, KCa3.1, and Kir2.1 expression in "classically" and "alternatively" activated microglia. Glia 2016; 65:106-121. [PMID: 27696527 PMCID: PMC5113690 DOI: 10.1002/glia.23078] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 09/15/2016] [Indexed: 11/10/2022]
Abstract
Microglia are highly plastic cells that can assume different phenotypes in response to microenvironmental signals. Lipopolysaccharide (LPS) and interferon-γ (IFN-γ) promote differentiation into classically activated M1-like microglia, which produce high levels of pro-inflammatory cytokines and nitric oxide and are thought to contribute to neurological damage in ischemic stroke and Alzheimer's disease. IL-4 in contrast induces a phenotype associated with anti-inflammatory effects and tissue repair. We here investigated whether these microglia subsets vary in their K+ channel expression by differentiating neonatal mouse microglia into M(LPS) and M(IL-4) microglia and studying their K+ channel expression by whole-cell patch-clamp, quantitative PCR and immunohistochemistry. We identified three major types of K+ channels based on their biophysical and pharmacological fingerprints: a use-dependent, outwardly rectifying current sensitive to the KV 1.3 blockers PAP-1 and ShK-186, an inwardly rectifying Ba2+ -sensitive Kir 2.1 current, and a Ca2+ -activated, TRAM-34-sensitive KCa 3.1 current. Both KV 1.3 and KCa 3.1 blockers inhibited pro-inflammatory cytokine production and iNOS and COX2 expression demonstrating that KV 1.3 and KCa 3.1 play important roles in microglia activation. Following differentiation with LPS or a combination of LPS and IFN-γ microglia exhibited high KV 1.3 current densities (∼50 pA/pF at 40 mV) and virtually no KCa 3.1 and Kir currents, while microglia differentiated with IL-4 exhibited large Kir 2.1 currents (∼ 10 pA/pF at -120 mV). KCa 3.1 currents were generally low but moderately increased following stimulation with IFN-γ or ATP (∼10 pS/pF). This differential K+ channel expression pattern suggests that KV 1.3 and KCa 3.1 inhibitors could be used to inhibit detrimental neuroinflammatory microglia functions. GLIA 2016;65:106-121.
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Affiliation(s)
- Hai M Nguyen
- Department of Pharmacology, University of California, Davis, California
| | - Eva M Grössinger
- Department of Pharmacology, University of California, Davis, California
| | - Makoto Horiuchi
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California.,M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, California
| | - Kyle W Davis
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California.,M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, California
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, California.,M.I.N.D. Institute, University of California Davis Medical Center, Davis, Sacramento, California
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California
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24
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Mechanisms Underlying Interferon-γ-Induced Priming of Microglial Reactive Oxygen Species Production. PLoS One 2016; 11:e0162497. [PMID: 27598576 PMCID: PMC5012572 DOI: 10.1371/journal.pone.0162497] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/23/2016] [Indexed: 01/01/2023] Open
Abstract
Microglial priming and enhanced reactivity to secondary insults cause substantial neuronal damage and are hallmarks of brain aging, traumatic brain injury and neurodegenerative diseases. It is, thus, of particular interest to identify mechanisms involved in microglial priming. Here, we demonstrate that priming of microglia with interferon-γ (IFN γ) substantially enhanced production of reactive oxygen species (ROS) following stimulation of microglia with ATP. Priming of microglial ROS production was substantially reduced by inhibition of p38 MAPK activity with SB203580, by increases in intracellular glutathione levels with N-Acetyl-L-cysteine, by blockade of NADPH oxidase subunit NOX2 activity with gp91ds-tat or by inhibition of nitric oxide production with L-NAME. Together, our data indicate that priming of microglial ROS production involves reduction of intracellular glutathione levels, upregulation of NADPH oxidase subunit NOX2 and increases in nitric oxide production, and suggest that these simultaneously occurring processes result in enhanced production of neurotoxic peroxynitrite. Furthermore, IFNγ-induced priming of microglial ROS production was reduced upon blockade of Kir2.1 inward rectifier K+ channels with ML133. Inhibitory effects of ML133 on microglial priming were mediated via regulation of intracellular glutathione levels and nitric oxide production. These data suggest that microglial Kir2.1 channels may represent novel therapeutic targets to inhibit excessive ROS production by primed microglia in brain pathology.
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