1
|
Navarro-Pérez M, Capera J, Benavente-Garcia A, Cassinelli S, Colomer-Molera M, Felipe A. Kv1.3 in the spotlight for treating immune diseases. Expert Opin Ther Targets 2024; 28:67-82. [PMID: 38316438 DOI: 10.1080/14728222.2024.2315021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/02/2024] [Indexed: 02/07/2024]
Abstract
INTRODUCTION Kv1.3 is the main voltage-gated potassium channel of leukocytes from both the innate and adaptive immune systems. Channel function is required for common processes such as Ca2+ signaling but also for cell-specific events. In this context, alterations in Kv1.3 are associated with multiple immune disorders. Excessive channel activity correlates with numerous autoimmune diseases, while reduced currents result in increased cancer prevalence and immunodeficiencies. AREAS COVERED This review offers a general view of the role of Kv1.3 in every type of leukocyte. Moreover, diseases stemming from dysregulations of the channel are detailed, as well as current advances in their therapeutic research. EXPERT OPINION Kv1.3 arises as a potential immune target in a variety of diseases. Several lines of research focused on channel modulation have yielded positive results. However, among the great variety of specific channel blockers, only one has reached clinical trials. Future investigations should focus on developing simpler administration routes for channel inhibitors to facilitate their entrance into clinical trials. Prospective Kv1.3-based treatments will ensure powerful therapies while minimizing undesired side effects.
Collapse
Affiliation(s)
- María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Jesusa Capera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Anna Benavente-Garcia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Silvia Cassinelli
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| |
Collapse
|
2
|
Sesti F, Bortolami A, Kathera-Ibarra EF. Non-conducting functions of potassium channels in cancer and neurological disease. CURRENT TOPICS IN MEMBRANES 2023; 92:199-231. [PMID: 38007268 DOI: 10.1016/bs.ctm.2023.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
Cancer and neurodegenerative disease, albeit fundamental differences, share some common pathogenic mechanisms. Accordingly, both conditions are associated with aberrant cell proliferation and migration. Here, we review the causative role played by potassium (K+) channels, a fundamental class of proteins, in cancer and neurodegenerative disease. The concept that emerges from the review of the literature is that K+ channels can promote the development and progression of cancerous and neurodegenerative pathologies by dysregulating cell proliferation and migration. K+ channels appear to control these cellular functions in ways that not necessarily depend on their conducting properties and that involve the ability to directly or indirectly engage growth and survival signaling pathways. As cancer and neurodegenerative disease represent global health concerns, identifying commonalities may help understand the molecular basis for those devastating conditions and may facilitate the design of new drugs or the repurposing of existing drugs.
Collapse
Affiliation(s)
- Federico Sesti
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Hoes Ln. West, Piscataway, NJ, United States.
| | - Alessandro Bortolami
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Hoes Ln. West, Piscataway, NJ, United States
| | - Elena Forzisi Kathera-Ibarra
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Hoes Ln. West, Piscataway, NJ, United States
| |
Collapse
|
3
|
Primak AL, Orlov NA, Peigneur S, Tytgat J, Ignatova AA, Denisova KR, Yakimov SA, Kirpichnikov MP, Nekrasova OV, Feofanov AV. AgTx2-GFP, Fluorescent Blocker Targeting Pharmacologically Important K v1.x (x = 1, 3, 6) Channels. Toxins (Basel) 2023; 15:toxins15030229. [PMID: 36977120 PMCID: PMC10056440 DOI: 10.3390/toxins15030229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
The growing interest in potassium channels as pharmacological targets has stimulated the development of their fluorescent ligands (including genetically encoded peptide toxins fused with fluorescent proteins) for analytical and imaging applications. We report on the properties of agitoxin 2 C-terminally fused with enhanced GFP (AgTx2-GFP) as one of the most active genetically encoded fluorescent ligands of potassium voltage-gated Kv1.x (x = 1, 3, 6) channels. AgTx2-GFP possesses subnanomolar affinities for hybrid KcsA-Kv1.x (x = 3, 6) channels and a low nanomolar affinity to KcsA-Kv1.1 with moderate dependence on pH in the 7.0-8.0 range. Electrophysiological studies on oocytes showed a pore-blocking activity of AgTx2-GFP at low nanomolar concentrations for Kv1.x (x = 1, 3, 6) channels and at micromolar concentrations for Kv1.2. AgTx2-GFP bound to Kv1.3 at the membranes of mammalian cells with a dissociation constant of 3.4 ± 0.8 nM, providing fluorescent imaging of the channel membranous distribution, and this binding depended weakly on the channel state (open or closed). AgTx2-GFP can be used in combination with hybrid KcsA-Kv1.x (x = 1, 3, 6) channels on the membranes of E. coli spheroplasts or with Kv1.3 channels on the membranes of mammalian cells for the search and study of nonlabeled peptide pore blockers, including measurement of their affinity.
Collapse
Affiliation(s)
- Alexandra L Primak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Nikita A Orlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Steve Peigneur
- Toxicology and Pharmacology, Campus Gasthuisberg O&N2, University of Leuven (KU Leuven), Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, Campus Gasthuisberg O&N2, University of Leuven (KU Leuven), Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Anastasia A Ignatova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Kristina R Denisova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Sergey A Yakimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| |
Collapse
|
4
|
De Felice E, Gonçalves de Andrade E, Golia MT, González Ibáñez F, Khakpour M, Di Castro MA, Garofalo S, Di Pietro E, Benatti C, Brunello N, Tascedda F, Kaminska B, Limatola C, Ragozzino D, Tremblay ME, Alboni S, Maggi L. Microglial diversity along the hippocampal longitudinal axis impacts synaptic plasticity in adult male mice under homeostatic conditions. J Neuroinflammation 2022; 19:292. [PMID: 36482444 PMCID: PMC9730634 DOI: 10.1186/s12974-022-02655-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
The hippocampus is a plastic brain area that shows functional segregation along its longitudinal axis, reflected by a higher level of long-term potentiation (LTP) in the CA1 region of the dorsal hippocampus (DH) compared to the ventral hippocampus (VH), but the mechanisms underlying this difference remain elusive. Numerous studies have highlighted the importance of microglia-neuronal communication in modulating synaptic transmission and hippocampal plasticity, although its role in physiological contexts is still largely unknown. We characterized in depth the features of microglia in the two hippocampal poles and investigated their contribution to CA1 plasticity under physiological conditions. We unveiled the influence of microglia in differentially modulating the amplitude of LTP in the DH and VH, showing that minocycline or PLX5622 treatment reduced LTP amplitude in the DH, while increasing it in the VH. This was recapitulated in Cx3cr1 knockout mice, indicating that microglia have a key role in setting the conditions for plasticity processes in a region-specific manner, and that the CX3CL1-CX3CR1 pathway is a key element in determining the basal level of CA1 LTP in the two regions. The observed LTP differences at the two poles were associated with transcriptional changes in the expression of genes encoding for Il-1, Tnf-α, Il-6, and Bdnf, essential players of neuronal plasticity. Furthermore, microglia in the CA1 SR region showed an increase in soma and a more extensive arborization, an increased prevalence of immature lysosomes accompanied by an elevation in mRNA expression of phagocytic markers Mertk and Cd68 and a surge in the expression of microglial outward K+ currents in the VH compared to DH, suggesting a distinct basal phenotypic state of microglia across the two hippocampal poles. Overall, we characterized the molecular, morphological, ultrastructural, and functional profile of microglia at the two poles, suggesting that modifications in hippocampal subregions related to different microglial statuses can contribute to dissect the phenotypical aspects of many diseases in which microglia are known to be involved.
Collapse
Affiliation(s)
- E. De Felice
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - E. Gonçalves de Andrade
- grid.143640.40000 0004 1936 9465Division of Medical Sciences, University of Victoria, Victoria, Canada
| | - M. T. Golia
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - F. González Ibáñez
- grid.143640.40000 0004 1936 9465Division of Medical Sciences, University of Victoria, Victoria, Canada ,grid.411081.d0000 0000 9471 1794Faculté de Médecine and Centre de Recherche, CHU de Québec-Université Laval, Quebec, Canada
| | - M. Khakpour
- grid.143640.40000 0004 1936 9465Division of Medical Sciences, University of Victoria, Victoria, Canada
| | - M. A. Di Castro
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - S. Garofalo
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - E. Di Pietro
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - C. Benatti
- grid.7548.e0000000121697570Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy ,grid.7548.e0000000121697570Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - N. Brunello
- grid.7548.e0000000121697570Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - F. Tascedda
- grid.7548.e0000000121697570Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy ,grid.7548.e0000000121697570Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - B. Kaminska
- grid.419305.a0000 0001 1943 2944Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - C. Limatola
- grid.419543.e0000 0004 1760 3561IRCCS Neuromed, Pozzilli, Italy ,grid.7841.aDepartment of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur, Sapienza University, Rome, Italy
| | - D. Ragozzino
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy ,grid.417778.a0000 0001 0692 3437Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
| | - M. E. Tremblay
- grid.143640.40000 0004 1936 9465Division of Medical Sciences, University of Victoria, Victoria, Canada ,grid.411081.d0000 0000 9471 1794Faculté de Médecine and Centre de Recherche, CHU de Québec-Université Laval, Quebec, Canada
| | - S. Alboni
- grid.7548.e0000000121697570Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy ,grid.7548.e0000000121697570Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - L. Maggi
- grid.7841.aDepartment of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| |
Collapse
|
5
|
Sarkar S. Microglial ion channels: Key players in non-cell autonomous neurodegeneration. Neurobiol Dis 2022; 174:105861. [PMID: 36115552 PMCID: PMC9617777 DOI: 10.1016/j.nbd.2022.105861] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/26/2022] [Accepted: 09/12/2022] [Indexed: 12/03/2022] Open
Abstract
Neuroinflammation is a critical pathophysiological hallmark of neurodegenerative disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and traumatic brain injury (TBI). Microglia, the first responders of the brain, are the drivers of this neuroinflammation. Microglial activation, leading to induction of pro-inflammatory factors, like Interleukin 1-β (IL-1β), Tumor necrosis factor-α (TNFα), nitrites, and others, have been shown to induce neurodegeneration. Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce the risk of developing PD, but the mechanism underlying the microglial activation is still under active research. Recently, microglial ion channels have come to the forefront as potential drug targets in multiple neurodegenerative disorders, including AD and PD. Microglia expresses a variety of ion channels, including potassium channels, calcium channels, chloride channels, sodium channels, and proton channels. The diversity of channels present on microglia is responsible for the dynamic nature of these immune cells of the brain. These ion channels regulate microglial proliferation, chemotaxis, phagocytosis, antigen recognition and presentation, apoptosis, and cell signaling leading to inflammation, among other critical functions. Understanding the role of these ion channels and the signaling mechanism these channels regulate under pathological conditions is an active area of research. This review will be focusing on the roles of different microglial ion channels, and their potential role in regulating microglial functions in neurodegenerative disorders.
Collapse
Affiliation(s)
- Souvarish Sarkar
- Dept. of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
6
|
Treatment of Radiation-Induced Brain Necrosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2021:4793517. [PMID: 34976300 PMCID: PMC8720020 DOI: 10.1155/2021/4793517] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/25/2021] [Accepted: 12/08/2021] [Indexed: 02/07/2023]
Abstract
Radiation-induced brain necrosis (RBN) is a serious complication of intracranial as well as skull base tumors after radiotherapy. In the past, due to the lack of effective treatment, radiation brain necrosis was considered to be progressive and irreversible. With better understanding in histopathology and neuroimaging, the occurrence and development of RBN have been gradually clarified, and new treatment methods are constantly emerging. In recent years, some scholars have tried to treat RBN with bevacizumab, nerve growth factor, and gangliosides and have achieved similar results. Some cases of brain necrosis can be repairable and reversible. We aimed to summarize the incidence, pathogenesis, and treatment of RBN.
Collapse
|
7
|
Cocozza G, Garofalo S, Capitani R, D’Alessandro G, Limatola C. Microglial Potassium Channels: From Homeostasis to Neurodegeneration. Biomolecules 2021; 11:1774. [PMID: 34944418 PMCID: PMC8698630 DOI: 10.3390/biom11121774] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/21/2022] Open
Abstract
The growing interest in the role of microglia in the progression of many neurodegenerative diseases is developing in an ever-expedited manner, in part thanks to emergent new tools for studying the morphological and functional features of the CNS. The discovery of specific biomarkers of the microglia phenotype could find application in a wide range of human diseases, and creates opportunities for the discovery and development of tailored therapeutic interventions. Among these, recent studies highlight the pivotal role of the potassium channels in regulating microglial functions in physiological and pathological conditions such as Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis. In this review, we summarize the current knowledge of the involvement of the microglial potassium channels in several neurodegenerative diseases and their role as modulators of microglial homeostasis and dysfunction in CNS disorders.
Collapse
Affiliation(s)
- Germana Cocozza
- Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy; (G.C.); (G.D.)
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (S.G.); (R.C.)
| | - Riccardo Capitani
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (S.G.); (R.C.)
| | - Giuseppina D’Alessandro
- Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy; (G.C.); (G.D.)
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (S.G.); (R.C.)
| | - Cristina Limatola
- Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy; (G.C.); (G.D.)
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University of Rome, 00185 Rome, Italy
| |
Collapse
|
8
|
Revealing the Precise Role of Calretinin Neurons in Epilepsy: We Are on the Way. Neurosci Bull 2021; 38:209-222. [PMID: 34324145 PMCID: PMC8821741 DOI: 10.1007/s12264-021-00753-1] [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: 01/21/2021] [Accepted: 04/24/2021] [Indexed: 02/03/2023] Open
Abstract
Epilepsy is a common neurological disorder characterized by hyperexcitability in the brain. Its pathogenesis is classically associated with an imbalance of excitatory and inhibitory neurons. Calretinin (CR) is one of the three major types of calcium-binding proteins present in inhibitory GABAergic neurons. The functions of CR and its role in neural excitability are still unknown. Recent data suggest that CR neurons have diverse neurotransmitters, morphologies, distributions, and functions in different brain regions across various species. Notably, CR neurons in the hippocampus, amygdala, neocortex, and thalamus are extremely susceptible to excitotoxicity in the epileptic brain, but the causal relationship is unknown. In this review, we focus on the heterogeneous functions of CR neurons in different brain regions and their relationship with neural excitability and epilepsy. Importantly, we provide perspectives on future investigations of the role of CR neurons in epilepsy.
Collapse
|
9
|
Liu J, Lv XW, Zhang L, Wang H, Li J, Wu B. Review on Biological Characteristics of Kv1.3 and Its Role in Liver Diseases. Front Pharmacol 2021; 12:652508. [PMID: 34093186 PMCID: PMC8176307 DOI: 10.3389/fphar.2021.652508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/23/2021] [Indexed: 01/30/2023] Open
Abstract
The liver accounts for the largest proportion of macrophages in all solid organs of the human body. Liver macrophages are mainly composed of cytolytic cells inherent in the liver and mononuclear macrophages recruited from the blood. Monocytes recruitment occurs mainly in the context of liver injury and inflammation and can be recruited into the liver and achieve a KC-like phenotype. During the immune response of the liver, macrophages/KC cells release inflammatory cytokines and infiltrate into the liver, which are considered to be the common mechanism of various liver diseases in the early stage. Meanwhile, macrophages/KC cells form an interaction network with other liver cells, which can affect the occurrence and progression of liver diseases. From the perspective of liver disease treatment, knowing the full spectrum of macrophage activation, the underlying molecular mechanisms, and their implication in either promoting liver disease progression or repairing injured liver tissue is highly relevant from a therapeutic point of view. Kv1.3 is a subtype of the voltage-dependent potassium channel, whose function is closely related to the regulation of immune cell function. At present, there are few studies on the relationship between Kv1.3 and liver diseases, and the application of its blockers as a potential treatment for liver diseases has not been reported. This manuscript reviewed the physiological characteristics of Kv1.3, the relationship between Kv1.3 and cell proliferation and apoptosis, and the role of Kv1.3 in a variety of liver diseases, so as to provide new ideas and strategies for the prevention and treatment of liver diseases. In short, by understanding the role of Kv1.3 in regulating the functions of immune cells such as macrophages, selective blockers of Kv1.3 or compounds with similar functions can be applied to alleviate the progression of liver diseases and provide new ideas for the prevention and treatment of liver diseases.
Collapse
Affiliation(s)
- Junda Liu
- First Affiliated Hospital of Anhui Medical University, Hefei, China.,School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Xiong-Wen Lv
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Lei Zhang
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Hua Wang
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| | - Baoming Wu
- School of Pharmacy, Anhui Medical University, Hefei, China.,Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, China
| |
Collapse
|
10
|
Tajti G, Wai DCC, Panyi G, Norton RS. The voltage-gated potassium channel K V1.3 as a therapeutic target for venom-derived peptides. Biochem Pharmacol 2020; 181:114146. [PMID: 32653588 DOI: 10.1016/j.bcp.2020.114146] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 02/07/2023]
Abstract
The voltage-gated potassium channel KV1.3 is a well-established therapeutic target for a range of autoimmune diseases, in addition to being the site of action of many venom-derived peptides. Numerous studies have documented the efficacy of venom peptides that target KV1.3, in particular from sea anemones and scorpions, in animal models of autoimmune diseases such as rheumatoid arthritis, psoriasis and multiple sclerosis. Moreover, an analogue of the sea anemone peptide ShK (known as dalazatide) has successfully completed Phase 1 clinical trials in mild-to-moderate plaque psoriasis. In this article we consider other potential therapeutic applications of inhibitors of KV1.3, including in inflammatory bowel disease and neuroinflammatory conditions such as Alzheimer's and Parkinson's diseases, as well as fibrotic diseases. We also summarise strategies for facilitating the entry of peptides to the central nervous system, given that this will be a pre-requisite for the treatment of most neuroinflammatory diseases. Venom-derived peptides that have been reported recently to target KV1.3 are also described. The increasing number of autoimmune and other conditions in which KV1.3 is upregulated and is therefore a potential therapeutic target, combined with the fact that many venom-derived peptides are potent inhibitors of KV1.3, suggests that venoms are likely to continue to serve as a rich source of new pharmacological tools and therapeutic leads targeting this channel.
Collapse
Affiliation(s)
- Gabor Tajti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC 3052, Australia.
| |
Collapse
|
11
|
Feng L, Murugan M, Bosco DB, Liu Y, Peng J, Worrell GA, Wang HL, Ta LE, Richardson JR, Shen Y, Wu LJ. Microglial proliferation and monocyte infiltration contribute to microgliosis following status epilepticus. Glia 2019; 67:1434-1448. [PMID: 31179602 DOI: 10.1002/glia.23616] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 12/15/2022]
Abstract
Microglial activation has been recognized as a major contributor to inflammation of the epileptic brain. Seizures are commonly accompanied by remarkable microgliosis and loss of neurons. In this study, we utilize the CX3CR1GFP/+ CCR2RFP/+ genetic mouse model, in which CX3CR1+ resident microglia and CCR2+ monocytes are labeled with GFP and RFP, respectively. Using a combination of time-lapse two-photon imaging and whole-cell patch clamp recording, we determined the distinct morphological, dynamic, and electrophysiological characteristics of infiltrated monocytes and resident microglia, and the evolution of their behavior at different time points following kainic acid-induced seizures. Seizure activated microglia presented enlarged somas with less ramified processes, whereas, infiltrated monocytes were smaller, highly motile cells that lacked processes. Moreover, resident microglia, but not infiltrated monocytes, proliferate locally in the hippocampus after seizure. Microglial proliferation was dependent on the colony-stimulating factor 1 receptor (CSF-1R) pathway. Pharmacological inhibition of CSF-1R reduced seizure-induced microglial proliferation, which correlated with attenuation of neuronal death without altering acute seizure behaviors. Taken together, we demonstrated that proliferation of activated resident microglia contributes to neuronal death in the hippocampus via CSF-1R after status epilepticus, providing potential therapeutic targets for neuroprotection in epilepsy.
Collapse
Affiliation(s)
- Lijie Feng
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China.,Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers University, Piscataway, New Jersey
| | - Madhuvika Murugan
- Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers University, Piscataway, New Jersey.,Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Dale B Bosco
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Yong Liu
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Jiyun Peng
- Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers University, Piscataway, New Jersey.,Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | | | - Hai-Long Wang
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Lauren E Ta
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Jason R Richardson
- Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, Florida
| | - Yuxian Shen
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Long-Jun Wu
- Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers University, Piscataway, New Jersey.,Department of Neurology, Mayo Clinic, Rochester, Minnesota.,Department of Neuroscience, Mayo Clinic, Jacksonville, Florida.,Department of Immunology, Mayo Clinic, Rochester, Minnesota
| |
Collapse
|
12
|
Sepulveda-Rodriguez A, Li P, Khan T, Ma JD, Carlone CA, Bozzelli PL, Conant KE, Forcelli PA, Vicini S. Electroconvulsive Shock Enhances Responsive Motility and Purinergic Currents in Microglia in the Mouse Hippocampus. eNeuro 2019; 6:ENEURO.0056-19.2019. [PMID: 31058213 PMCID: PMC6498419 DOI: 10.1523/eneuro.0056-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/09/2019] [Indexed: 12/24/2022] Open
Abstract
Microglia are in a privileged position to both affect and be affected by neuroinflammation, neuronal activity and injury, which are all hallmarks of seizures and the epilepsies. Hippocampal microglia become activated after prolonged, damaging seizures known as status epilepticus (SE). However, since SE causes both hyperactivity and injury of neurons, the mechanisms triggering this activation remain unclear, as does the relevance of the microglial activation to the ensuing epileptogenic processes. In this study, we use electroconvulsive shock (ECS) to study the effect of neuronal hyperactivity without neuronal degeneration on mouse hippocampal microglia. Unlike SE, ECS did not alter hippocampal CA1 microglial density, morphology, or baseline motility. In contrast, both ECS and SE produced a similar increase in ATP-directed microglial process motility in acute slices, and similarly upregulated expression of the chemokine C-C motif chemokine ligand 2 (CCL2). Whole-cell patch-clamp recordings of hippocampal CA1sr microglia showed that ECS enhanced purinergic currents mediated by P2X7 receptors in the absence of changes in passive properties or voltage-gated currents, or changes in receptor expression. This differs from previously described alterations in intrinsic characteristics which coincided with enhanced purinergic currents following SE. These ECS-induced effects point to a "seizure signature" in hippocampal microglia characterized by altered purinergic signaling. These data demonstrate that ictal activity per se can drive alterations in microglial physiology without neuronal injury. These physiological changes, which up until now have been associated with prolonged and damaging seizures, are of added interest as they may be relevant to electroconvulsive therapy (ECT), which remains a gold-standard treatment for depression.
Collapse
Affiliation(s)
- Alberto Sepulveda-Rodriguez
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007
| | - Pinggan Li
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
- Department of Pediatrics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Tahiyana Khan
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007
| | - James D Ma
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
| | - Colby A Carlone
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
| | - P Lorenzo Bozzelli
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007
- Department of Neuroscience, Georgetown University, Washington, DC 20007
| | - Katherine E Conant
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007
- Department of Neuroscience, Georgetown University, Washington, DC 20007
| | - Patrick A Forcelli
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007
| |
Collapse
|
13
|
Lively S, Wong R, Lam D, Schlichter LC. Sex- and Development-Dependent Responses of Rat Microglia to Pro- and Anti-inflammatory Stimulation. Front Cell Neurosci 2018; 12:433. [PMID: 30524242 PMCID: PMC6262307 DOI: 10.3389/fncel.2018.00433] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/31/2018] [Indexed: 11/23/2022] Open
Abstract
Addressing potential sex differences in pre-clinical studies is crucial for developing therapeutic interventions. Although sex differences have been reported in epidemiological studies and from clinical experience, most pre-clinical studies of neuroinflammation use male rodents; however, sexual dimorphisms in microglia might affect the CNS inflammatory response. Developmental changes are also important and, in rodents, there is a critical period of sexual brain differentiation in the first 3 weeks after birth. We compared rat microglia from sex-segregated neonates (P1) and at about the time of weaning (P21). To study transitions from a basal homeostatic state (untreated), microglia were subjected to a pro-inflammatory (IFNγ + TNFα) or anti-inflammatory (IL-4) stimulus. Responses were compared by quantifying changes in nitric oxide production, migration, and expression of nearly 70 genes, including inflammatory mediators and receptors, inflammasome molecules, immune modulators, and genes that regulate microglial physiological functions. No sex differences were seen in transcriptional responses in either age group but the IL-4-evoked migration increase was larger in male cells at both ages. Protein changes for the hallmark molecules, NOS2, COX-2, PYK2 and CD206 correlated with mRNA changes. P1 and P21 microglia showed substantial differences, including expression of genes related to developmental roles. That is, P21 microglia had a more mature phenotype, with higher basal and stimulated levels of many inflammatory genes, while P1 cells had higher expression of phagocytosis-related molecules. Nevertheless, cells of both ages responded to IL-4 and IFNγ + TNFα. We examined the Kv1.3 potassium channel (a potential target for modulating neuroinflammation) and the Kir2.1 channel, which regulate several microglia functions. Kv1.3 mRNA (Kcna3) was higher at P21 under all conditions and male P21 cells had higher mRNA and Kv currents in response to IFNγ + TNFα. Overall, numerous transcriptional and functional responses of microglia changed during the first 3 weeks after birth but few sex-dependent changes were seen.
Collapse
Affiliation(s)
- Starlee Lively
- Division of Genetics & Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Raymond Wong
- Division of Genetics & Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Doris Lam
- Division of Genetics & Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Lyanne C Schlichter
- Division of Genetics & Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
14
|
Thei L, Imm J, Kaisis E, Dallas ML, Kerrigan TL. Microglia in Alzheimer's Disease: A Role for Ion Channels. Front Neurosci 2018; 12:676. [PMID: 30323735 PMCID: PMC6172337 DOI: 10.3389/fnins.2018.00676] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/07/2018] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease is the most common form of dementia, it is estimated to affect over 40 million people worldwide. Classically, the disease has been characterized by the neuropathological hallmarks of aggregated extracellular amyloid-β and intracellular paired helical filaments of hyperphosphorylated tau. A wealth of evidence indicates a pivotal role for the innate immune system, such as microglia, and inflammation in the pathology of Alzheimer's disease. The over production and aggregation of Alzheimer's associated proteins results in chronic inflammation and disrupts microglial clearance of these depositions. Despite being non-excitable, microglia express a diverse array of ion channels which shape their physiological functions. In support of this, there is a growing body of evidence pointing to the involvement of microglial ion channels contributing to neurodegenerative diseases such as Alzheimer's disease. In this review, we discuss the evidence for an array of microglia ion channels and their importance in modulating microglial homeostasis and how this process could be disrupted in Alzheimer's disease. One promising avenue for assessing the role that microglia play in the initiation and progression of Alzheimer's disease is through using induced pluripotent stem cell derived microglia. Here, we examine what is already understood in terms of the molecular underpinnings of inflammation in Alzheimer's disease, and the utility that inducible pluripotent stem cell derived microglia may have to advance this knowledge. We outline the variability that occurs between the use of animal and human models with regards to the importance of microglial ion channels in generating a relevant functional model of brain inflammation. Overcoming these hurdles will be pivotal in order to develop new drug targets and progress our understanding of the pathological mechanisms involved in Alzheimer's disease.
Collapse
Affiliation(s)
- Laura Thei
- Reading School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Jennifer Imm
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Eleni Kaisis
- Reading School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Mark L Dallas
- Reading School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Talitha L Kerrigan
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| |
Collapse
|
15
|
Plescher M, Seifert G, Hansen JN, Bedner P, Steinhäuser C, Halle A. Plaque-dependent morphological and electrophysiological heterogeneity of microglia in an Alzheimer's disease mouse model. Glia 2018; 66:1464-1480. [PMID: 29493017 DOI: 10.1002/glia.23318] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 01/17/2018] [Accepted: 02/12/2018] [Indexed: 12/18/2022]
Abstract
Microglia, the central nervous system resident innate immune cells, cluster around Aβ plaques in Alzheimer's disease (AD). The activation phenotype of these plaque-associated microglial cells, and their differences to microglia distant to Aβ plaques, are incompletely understood. We used novel three-dimensional cell analysis software to comprehensively analyze the morphological properties of microglia in the TgCRND8 mouse model of AD in spatial relation to Aβ plaques. We found strong morphological changes exclusively in plaque-associated microglia, whereas plaque-distant microglia showed only minor changes. In addition, patch-clamp recordings of microglia in acute cerebral slices of TgCRND8 mice revealed increased K+ currents in plaque-associated but not plaque-distant microglia. Within the subgroup of plaque-associated microglia, two different current profiles were detected. One subset of cells displayed only increased inward currents, while a second subset showed both increased inward and outward currents, implicating that the plaque microenvironment differentially impacts microglial ion channel expression. Using pharmacological channel blockers, multiplex single-cell PCR analysis and RNA fluorescence in situ hybridization, we identified Kir and Kv channel types contributing to the in- and outward K+ conductance in plaque-associated microglia. In summary, we have identified a previously unrecognized level of morphological and electrophysiological heterogeneity of microglia in relation to amyloid plaques, suggesting that microglia may display multiple activation states in AD.
Collapse
Affiliation(s)
- Monika Plescher
- German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany.,Center of Advanced European Studies and Research, Bonn, Germany.,Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Jan Niklas Hansen
- German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany.,Center of Advanced European Studies and Research, Bonn, Germany
| | - Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Annett Halle
- German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany.,Center of Advanced European Studies and Research, Bonn, Germany
| |
Collapse
|
16
|
Lam D, Lively S, Schlichter LC. Responses of rat and mouse primary microglia to pro- and anti-inflammatory stimuli: molecular profiles, K + channels and migration. J Neuroinflammation 2017; 14:166. [PMID: 28830445 PMCID: PMC5567442 DOI: 10.1186/s12974-017-0941-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/13/2017] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Acute CNS damage is commonly studied using rat and mouse models, but increasingly, molecular analysis is finding species differences that might affect the ability to translate findings to humans. Microglia can undergo complex molecular and functional changes, often studied by in vitro responses to discrete activating stimuli. There is considerable evidence that pro-inflammatory (M1) activation can exacerbate tissue damage, while anti-inflammatory (M2) states help resolve inflammation and promote tissue repair. However, in assessing potential therapeutic targets for controlling inflammation, it is crucial to determine whether rat and mouse microglia respond the same. METHODS Primary microglia from Sprague-Dawley rats and C57BL/6 mice were cultured, then stimulated with interferon-γ + tumor necrosis factor-α (I + T; M1 activation), interleukin (IL)-4 (M2a, alternative activation), or IL-10 (M2c, acquired deactivation). To profile their activation responses, NanoString was used to monitor messenger RNA (mRNA) expression of numerous pro- and anti-inflammatory mediators, microglial markers, immunomodulators, and other molecules. Western analysis was used to measure selected proteins. Two potential targets for controlling inflammation-inward- and outward-rectifier K+ channels (Kir2.1, Kv1.3)-were examined (mRNA, currents) and specific channel blockers were applied to determine their contributions to microglial migration in the different activation states. RESULTS Pro-inflammatory molecules increased after I + T treatment but there were several qualitative and quantitative differences between the species (e.g., iNOS and nitric oxide, COX-2). Several molecules commonly associated with an M2a state differed between species or they were induced in additional activation states (e.g., CD206, ARG1). Resting levels and/or responses of several microglial markers (Iba1, CD11b, CD68) differed with the activation state, species, or both. Transcripts for several Kir2 and Kv1 family members were detected in both species. However, the current amplitudes (mainly Kir2.1 and Kv1.3) depended on activation state and species. Treatment-induced changes in morphology and migratory capacity were similar between the species (migration reduced by I + T, increased by IL-4 or IL-10). In both species, Kir2.1 block reduced migration and Kv1.3 block increased it, regardless of activation state; thus, these channels might affect microglial migration to damage sites. CONCLUSIONS Caution is recommended in generalizing molecular and functional responses of microglia to activating stimuli between species.
Collapse
Affiliation(s)
- Doris Lam
- Genes and Development Division, Krembil Research Institute, University Health Network, Krembil Discovery Tower, Room 7KD417, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Starlee Lively
- Genes and Development Division, Krembil Research Institute, University Health Network, Krembil Discovery Tower, Room 7KD417, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada
| | - Lyanne C Schlichter
- Genes and Development Division, Krembil Research Institute, University Health Network, Krembil Discovery Tower, Room 7KD417, 60 Leonard Avenue, Toronto, ON, M5T 2S8, Canada. .,Department of Physiology, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
17
|
Rangaraju S, Raza SA, Pennati A, Deng Q, Dammer EB, Duong D, Pennington MW, Tansey MG, Lah JJ, Betarbet R, Seyfried NT, Levey AI. A systems pharmacology-based approach to identify novel Kv1.3 channel-dependent mechanisms in microglial activation. J Neuroinflammation 2017. [PMID: 28651603 PMCID: PMC5485721 DOI: 10.1186/s12974-017-0906-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Kv1.3 potassium channels regulate microglial functions and are overexpressed in neuroinflammatory diseases. Kv1.3 blockade may selectively inhibit pro-inflammatory microglia in neurological diseases but the molecular and cellular mechanisms regulated by Kv1.3 channels are poorly defined. METHODS We performed immunoblotting and flow cytometry to confirm Kv1.3 channel upregulation in lipopolysaccharide (LPS)-activated BV2 microglia and in brain mononuclear phagocytes freshly isolated from LPS-treated mice. Quantitative proteomics was performed on BV2 microglia treated with control, LPS, ShK-223 (highly selective Kv1.3 blocker), and LPS+ShK-223. Gene ontology (GO) analyses of Kv1.3-dependent LPS-regulated proteins were performed, and the most representative proteins and GO terms were validated. Effects of Kv1.3-blockade on LPS-activated BV2 microglia were studied in migration, focal adhesion formation, reactive oxygen species production, and phagocytosis assays. In vivo validation of protein changes and predicted molecular pathways were performed in a model of systemic LPS-induced neuroinflammation, employing antigen presentation and T cell proliferation assays. Informed by pathway analyses of proteomic data, additional mechanistic experiments were performed to identify early Kv1.3-dependent signaling and transcriptional events. RESULTS LPS-upregulated cell surface Kv1.3 channels in BV2 microglia and in microglia and CNS-infiltrating macrophages isolated from LPS-treated mice. Of 144 proteins differentially regulated by LPS (of 3141 proteins), 21 proteins showed rectification by ShK-223. Enriched cellular processes included MHCI-mediated antigen presentation (TAP1, EHD1), cell motility, and focal adhesion formation. In vitro, ShK-223 decreased LPS-induced focal adhesion formation, reversed LPS-induced inhibition of migration, and inhibited LPS-induced upregulation of EHD1, a protein involved in MHCI trafficking. In vivo, intra-peritoneal ShK-223 inhibited LPS-induced MHCI expression by CD11b+CD45low microglia without affecting MHCI expression or trafficking of CD11b+CD45high macrophages. ShK-223 inhibited LPS-induced MHCI-restricted antigen presentation to ovalbumin-specific CD8+ T cells both in vitro and in vivo. Kv1.3 co-localized with the LPS receptor complex and regulated LPS-induced early serine (S727) STAT1 phosphorylation. CONCLUSIONS We have unraveled novel molecular and functional roles for Kv1.3 channels in pro-inflammatory microglial activation, including a Kv1.3 channel-regulated pathway that facilitates MHCI expression and MHCI-dependent antigen presentation by microglia to CD8+ T cells. We also provide evidence for neuro-immunomodulation by systemically administered ShK peptides. Our results further strengthen the therapeutic candidacy of microglial Kv1.3 channels in neurologic diseases.
Collapse
Affiliation(s)
- Srikant Rangaraju
- Department of Neurology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA.
| | - Syed Ali Raza
- Department of Neurology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - Andrea Pennati
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53726, USA
| | - Qiudong Deng
- Department of Biochemistry, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - Eric B Dammer
- Department of Neurology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - Duc Duong
- Department of Biochemistry, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | | | - Malu G Tansey
- Department of Physiology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - James J Lah
- Department of Neurology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - Ranjita Betarbet
- Department of Neurology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| | - Allan I Levey
- Department of Neurology, Emory University, 615 Michael Street, Suite 525, Atlanta, GA, 30322, USA
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Mosser CA, Baptista S, Arnoux I, Audinat E. Microglia in CNS development: Shaping the brain for the future. Prog Neurobiol 2017; 149-150:1-20. [DOI: 10.1016/j.pneurobio.2017.01.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 12/22/2022]
|
20
|
Schwartz AB, Kapur A, Wang W, Huang Z, Fardone E, Palui G, Mattoussi H, Fadool DA. Margatoxin-bound quantum dots as a novel inhibitor of the voltage-gated ion channel Kv1.3. J Neurochem 2016; 140:404-420. [PMID: 27861889 DOI: 10.1111/jnc.13891] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 10/24/2016] [Accepted: 10/31/2016] [Indexed: 01/01/2023]
Abstract
Venom-derived ion channel inhibitors have strong channel selectivity, potency, and stability; however, tracking delivery to their target can be challenging. Herein, we utilized luminescent quantum dots (QDs) conjugated to margatoxin (MgTx) as a traceable vehicle to target a voltage-dependent potassium channel, Kv1.3, which has a select distribution and well-characterized role in immunity, glucose metabolism, and sensory ability. We screened both unconjugated (MgTx) and conjugated MgTx (QD-MgTx) for their ability to inhibit Shaker channels Kv1.1 to Kv1.7 using patch-clamp electrophysiology in HEK293 cells. Our data indicate that MgTx inhibits 79% of the outward current in Kv1.3-transfected cells and that the QD-MgTx conjugate is able to achieve a similar level of block, albeit a slightly reduced efficacy (66%) and at a slower time course (50% block by 10.9 ± 1.1 min, MgTx; vs. 15.3 ± 1.2 min, QD-MgTx). Like the unbound peptide, the QD-MgTx conjugate inhibits both Kv1.3 and Kv1.2 at a 1 nM concentration, whereas it does not inhibit other screened Shaker channels. We tested the ability of QD-MgTx to inhibit native Kv1.3 expressed in the mouse olfactory bulb (OB). In brain slices of the OB, the conjugate acted similarly to MgTx to inhibit Kv1.3, causing an increased action potential firing frequency attributed to decreased intraburst duration rather than interspike interval. Our data demonstrate a retention of known biophysical properties associated with block of the vestibule of Kv1.3 by QD-MgTx conjugate compared to that of MgTx, inferring QDs could provide a useful tool to deliver ion channel inhibitors to targeted tissues in vivo.
Collapse
Affiliation(s)
- Austin B Schwartz
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Anshika Kapur
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Wentao Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Zhenbo Huang
- Program in Neuroscience, Florida State University, Tallahassee, Florida, USA
| | - Erminia Fardone
- Program in Neuroscience, Florida State University, Tallahassee, Florida, USA.,Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Goutam Palui
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Hedi Mattoussi
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Debra Ann Fadool
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA.,Program in Neuroscience, Florida State University, Tallahassee, Florida, USA.,Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| |
Collapse
|
21
|
Reeves TM, Trimmer PA, Colley BS, Phillips LL. Targeting Kv1.3 channels to reduce white matter pathology after traumatic brain injury. Exp Neurol 2016; 283:188-203. [PMID: 27302680 PMCID: PMC4992637 DOI: 10.1016/j.expneurol.2016.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/31/2016] [Accepted: 06/10/2016] [Indexed: 02/07/2023]
Abstract
Axonal injury is present in essentially all clinically significant cases of traumatic brain injury (TBI). While no effective treatment has been identified to date, experimental TBI models have shown promising axonal protection using immunosuppressants FK506 and Cyclosporine-A, with treatment benefits attributed to calcineurin inhibition or protection of mitochondrial function. However, growing evidence suggests neuroprotective efficacy of these compounds may also involve direct modulation of ion channels, and in particular Kv1.3. The present study tested whether blockade of Kv1.3 channels, using Clofazimine (CFZ), would alleviate TBI-induced white matter pathology in rodents. Postinjury CFZ administration prevented suppression of compound action potential (CAP) amplitude in the corpus callosum of adult rats following midline fluid percussion TBI, with injury and treatment effects primarily expressed in unmyelinated CAPs. Kv1.3 protein levels in callosal tissue extracts were significantly reduced postinjury, but this loss was prevented by CFZ treatment. In parallel, CFZ also attenuated the injury-induced elevation in pro-inflammatory cytokine IL1-β. The effects of CFZ on glial function were further studied using mixed microglia/astrocyte cell cultures derived from P3-5 mouse corpus callosum. Cultures of callosal glia challenged with lipopolysaccharide exhibited a dramatic increase in IL1-β levels, accompanied by reactive morphological changes in microglia, both of which were attenuated by CFZ treatment. These results support a cell specific role for Kv1.3 signaling in white matter pathology after TBI, and suggest a treatment approach based on the blockade of these channels. This therapeutic strategy may be especially efficacious for normalizing neuro-glial interactions affecting unmyelinated axons after TBI.
Collapse
Affiliation(s)
- Thomas M Reeves
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Patricia A Trimmer
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Beverly S Colley
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Linda L Phillips
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| |
Collapse
|
22
|
KV1 and KV3 Potassium Channels Identified at Presynaptic Terminals of the Corticostriatal Synapses in Rat. Neural Plast 2016; 2016:8782518. [PMID: 27379187 PMCID: PMC4917754 DOI: 10.1155/2016/8782518] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/12/2016] [Accepted: 05/16/2016] [Indexed: 12/19/2022] Open
Abstract
In the last years it has been increasingly clear that KV-channel activity modulates neurotransmitter release. The subcellular localization and composition of potassium channels are crucial to understanding its influence on neurotransmitter release. To investigate the role of KV in corticostriatal synapses modulation, we combined extracellular recording of population-spike and pharmacological blockage with specific and nonspecific blockers to identify several families of KV channels. We induced paired-pulse facilitation (PPF) and studied the changes in paired-pulse ratio (PPR) before and after the addition of specific KV blockers to determine whether particular KV subtypes were located pre- or postsynaptically. Initially, the presence of KV channels was tested by exposing brain slices to tetraethylammonium or 4-aminopyridine; in both cases we observed a decrease in PPR that was dose dependent. Further experiments with tityustoxin, margatoxin, hongotoxin, agitoxin, dendrotoxin, and BDS-I toxins all rendered a reduction in PPR. In contrast heteropodatoxin and phrixotoxin had no effect. Our results reveal that corticostriatal presynaptic KV channels have a complex stoichiometry, including heterologous combinations KV1.1, KV1.2, KV1.3, and KV1.6 isoforms, as well as KV3.4, but not KV4 channels. The variety of KV channels offers a wide spectrum of possibilities to regulate neurotransmitter release, providing fine-tuning mechanisms to modulate synaptic strength.
Collapse
|
23
|
Kv1.3 potassium channel mediates macrophage migration in atherosclerosis by regulating ERK activity. Arch Biochem Biophys 2016; 591:150-6. [DOI: 10.1016/j.abb.2015.12.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 12/05/2015] [Accepted: 12/29/2015] [Indexed: 12/30/2022]
|
24
|
Pérez-Verdaguer M, Capera J, Serrano-Novillo C, Estadella I, Sastre D, Felipe A. The voltage-gated potassium channel Kv1.3 is a promising multitherapeutic target against human pathologies. Expert Opin Ther Targets 2015; 20:577-91. [DOI: 10.1517/14728222.2016.1112792] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
25
|
Rangaraju S, Gearing M, Jin LW, Levey A. Potassium channel Kv1.3 is highly expressed by microglia in human Alzheimer's disease. J Alzheimers Dis 2015; 44:797-808. [PMID: 25362031 DOI: 10.3233/jad-141704] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Recent genetic studies suggest a central role for innate immunity in Alzheimer's disease (AD) pathogenesis, wherein microglia orchestrate neuroinflammation. Kv1.3, a voltage-gated potassium channel of therapeutic relevance in autoimmunity, is upregulated by activated microglia and mediates amyloid-mediated microglial priming and reactive oxygen species production in vitro. We hypothesized that Kv1.3 channel expression is increased in human AD brain tissue. In a blinded postmortem immunohistochemical semi-quantitative analysis performed on ten AD patients and ten non-disease controls, we observed a significantly higher Kv1.3 staining intensity (p = 0.03) and Kv1.3-positive cell density (p = 0.03) in the frontal cortex of AD brains, compared to controls. This paralleled an increased number of Iba1-positive microglia in AD brains. Kv1.3-positive cells had microglial morphology and were associated with amyloid-β plaques. In immunofluorescence studies, Kv1.3 channels co-localized primarily with Iba1 but not with astrocyte marker GFAP, confirming that elevated Kv1.3 expression is limited to microglia. Higher Kv1.3 expression in AD brains was also confirmed by western blot analysis. Our findings support that Kv1.3 channels are biologically relevant and microglia-specific targets in human AD.
Collapse
Affiliation(s)
| | - Marla Gearing
- Department of Neurology, Emory University, Atlanta, GA, USA
| | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine, Alzheimer's Disease Center, University of California Davis, CA, USA
| | - Allan Levey
- Department of Neurology, Emory University, Atlanta, GA, USA
| |
Collapse
|
26
|
Huchtemann T, Körtvélyessy P, Feistner H, Heinze HJ, Bittner D. Progranulin levels in status epilepticus as a marker of neuronal recovery and neuroprotection. Epilepsy Behav 2015. [PMID: 26211941 DOI: 10.1016/j.yebeh.2015.06.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
INTRODUCTION Recently, a mouse model showed that progranulin, a mediator in neuroinflammation and a neuronal growth factor, was elevated in the hippocampus after status epilepticus (SE). This elevated level might mirror compensating neuronal mechanisms after SE. Studies concerning neuronal recovery and neuroprotective mechanisms after SE in humans are scarce, so we tested for progranulinin the cerebrospinal fluid (CSF) after various types of SE. METHOD We performed a retrospective analysis of progranulin levels in CSF in patients (n = 24) who underwent lumbar puncture as part of diagnostic workup after having SE and in patients after having one single tonic-clonic seizure who comprised the control group (n = 8). RESULTS In our group with SE, progranulin levels in CSF were not significantly elevated compared to our control group. Furthermore, there was no correlation between progranulin levels and the time interval between lumbar puncture and SE. Additionally, in cases of higher CSF progranulin levels, we found no impact on the clinical outcome after SE. CONCLUSION Although our cohort is heterogeneous and not fully sufficient, we conclude that progranulin in CSF is not elevated after SE in our cohort. Therefore, our results do not suggest a change in cerebral progranulin metabolism as a possible neuroregenerative or neuroprotective mechanism in humans after SE in acute and subacute phases. A larger cohort study is needed to further strengthen this result. This article is part of a Special Issue entitled "Status Epilepticus".
Collapse
Affiliation(s)
- T Huchtemann
- Department of Neurology, University Hospital Magdeburg, Germany
| | - P Körtvélyessy
- Department of Neurology, University Hospital Magdeburg, Germany.
| | - H Feistner
- Department of Neurology, University Hospital Magdeburg, Germany
| | - H J Heinze
- Department of Neurology, University Hospital Magdeburg, Germany; Leibniz Institute of Neurobiology, Magdeburg, Germany
| | - D Bittner
- Department of Neurology, University Hospital Magdeburg, Germany
| |
Collapse
|
27
|
Wolfart J, Laker D. Homeostasis or channelopathy? Acquired cell type-specific ion channel changes in temporal lobe epilepsy and their antiepileptic potential. Front Physiol 2015; 6:168. [PMID: 26124723 PMCID: PMC4467176 DOI: 10.3389/fphys.2015.00168] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/19/2015] [Indexed: 01/16/2023] Open
Abstract
Neurons continuously adapt the expression and functionality of their ion channels. For example, exposed to chronic excitotoxicity, neurons homeostatically downscale their intrinsic excitability. In contrast, the “acquired channelopathy” hypothesis suggests that proepileptic channel characteristics develop during epilepsy. We review cell type-specific channel alterations under different epileptic conditions and discuss the potential of channels that undergo homeostatic adaptations, as targets for antiepileptic drugs (AEDs). Most of the relevant studies have been performed on temporal lobe epilepsy (TLE), a widespread AED-refractory, focal epilepsy. The TLE patients, who undergo epilepsy surgery, frequently display hippocampal sclerosis (HS), which is associated with degeneration of cornu ammonis subfield 1 pyramidal cells (CA1 PCs). Although the resected human tissue offers insights, controlled data largely stem from animal models simulating different aspects of TLE and other epilepsies. Most of the cell type-specific information is available for CA1 PCs and dentate gyrus granule cells (DG GCs). Between these two cell types, a dichotomy can be observed: while DG GCs acquire properties decreasing the intrinsic excitability (in TLE models and patients with HS), CA1 PCs develop channel characteristics increasing intrinsic excitability (in TLE models without HS only). However, thorough examination of data on these and other cell types reveals the coexistence of protective and permissive intrinsic plasticity within neurons. These mechanisms appear differentially regulated, depending on the cell type and seizure condition. Interestingly, the same channel molecules that are upregulated in DG GCs during HS-related TLE, appear as promising targets for future AEDs and gene therapies. Hence, GCs provide an example of homeostatic ion channel adaptation which can serve as a primer when designing novel anti-epileptic strategies.
Collapse
Affiliation(s)
- Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Debora Laker
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| |
Collapse
|
28
|
Charolidi N, Schilling T, Eder C. Microglial Kv1.3 Channels and P2Y12 Receptors Differentially Regulate Cytokine and Chemokine Release from Brain Slices of Young Adult and Aged Mice. PLoS One 2015; 10:e0128463. [PMID: 26011191 PMCID: PMC4444306 DOI: 10.1371/journal.pone.0128463] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/27/2015] [Indexed: 01/08/2023] Open
Abstract
Brain tissue damage following stroke or traumatic brain injury is accompanied by neuroinflammatory processes, while microglia play a central role in causing and regulating neuroinflammation via production of proinflammatory substances, including cytokines and chemokines. Here, we used brain slices, an established in situ brain injury model, from young adult and aged mice to investigate cytokine and chemokine production with particular focus on the role of microglia. Twenty four hours after slice preparation, higher concentrations of proinflammatory cytokines, i.e. TNF-α and IL-6, and chemokines, i.e. CCL2 and CXCL1, were released from brain slices of aged mice than from slices of young adult mice. However, maximal microglial stimulation with LPS for 24 h did not reveal age-dependent differences in the amounts of released cytokines and chemokines. Mechanisms underlying microglial cytokine and chemokine production appear to be similar in young adult and aged mice. Inhibition of microglial Kv1.3 channels with margatoxin reduced release of IL-6, but not release of CCL2 and CXCL1. In contrast, blockade of microglial P2Y12 receptors with PSB0739 inhibited release of CCL2 and CXCL1, whereas release of IL-6 remained unaffected. Cytokine and chemokine production was not reduced by inhibitors of Kir2.1 K+ channels or adenosine receptors. In summary, our data suggest that brain tissue damage-induced production of cytokines and chemokines is age-dependent, and differentially regulated by microglial Kv1.3 channels and P2Y12 receptors.
Collapse
Affiliation(s)
- Nicoletta Charolidi
- Institute for Infection and Immunity; St. George’s, University of London; Cranmer Terrace; London SW17 0RE, United Kingdom
| | - Tom Schilling
- Institute for Infection and Immunity; St. George’s, University of London; Cranmer Terrace; London SW17 0RE, United Kingdom
| | - Claudia Eder
- Institute for Infection and Immunity; St. George’s, University of London; Cranmer Terrace; London SW17 0RE, United Kingdom
- * E-mail:
| |
Collapse
|
29
|
Pagani F, Paolicelli RC, Murana E, Cortese B, Di Angelantonio S, Zurolo E, Guiducci E, Ferreira TA, Garofalo S, Catalano M, D'Alessandro G, Porzia A, Peruzzi G, Mainiero F, Limatola C, Gross CT, Ragozzino D. Defective microglial development in the hippocampus of Cx3cr1 deficient mice. Front Cell Neurosci 2015; 9:111. [PMID: 25873863 PMCID: PMC4379915 DOI: 10.3389/fncel.2015.00111] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/11/2015] [Indexed: 11/13/2022] Open
Abstract
Microglial cells participate in brain development and influence neuronal loss and synaptic maturation. Fractalkine is an important neuronal chemokine whose expression increases during development and that can influence microglia function via the fractalkine receptor, CX3CR1. Mice lacking Cx3cr1 show a variety of neuronal defects thought to be the result of deficient microglia function. Activation of CX3CR1 is important for the proper migration of microglia to sites of injury and into the brain during development. However, little is known about how fractalkine modulates microglial properties during development. Here we examined microglial morphology, response to ATP, and K+ current properties in acute brain slices from Cx3cr1 knockout mice across postnatal hippocampal development. We found that fractalkine signaling is necessary for the development of several morphological and physiological features of microglia. Specifically, we found that the occurrence of an outward rectifying K+ current, typical of activated microglia, that peaked during the second and third postnatal week, was reduced in Cx3cr1 knockout mice. Fractalkine signaling also influenced microglial morphology and ability to extend processes in response to ATP following its focal application to the slice. Our results reveal the developmental profile of several morphological and physiological properties of microglia and demonstrate that these processes are modulated by fractalkine signaling.
Collapse
Affiliation(s)
- Francesca Pagani
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy
| | - Rosa C Paolicelli
- Division of Psychiatry Research, University of Zürich, Zürich Switzerland ; Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Emanuele Murana
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Barbara Cortese
- Consiglio Nazionale delle Ricerche - Institute of Inorganic Methodologies and Plasmas, Department of Physics, Sapienza University of Rome, Rome Italy
| | - Silvia Di Angelantonio
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy ; Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Emanuele Zurolo
- Department of Neuropathology, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Eva Guiducci
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Tiago A Ferreira
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Myriam Catalano
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Giuseppina D'Alessandro
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Alessandra Porzia
- Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome Rome, Italy
| | - Giovanna Peruzzi
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy
| | - Fabrizio Mainiero
- Department of Experimental Medicine, Sapienza University of Rome Rome, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Cornelius T Gross
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| |
Collapse
|
30
|
Schilling T, Eder C. Microglial K(+) channel expression in young adult and aged mice. Glia 2014; 63:664-72. [PMID: 25472417 PMCID: PMC4359010 DOI: 10.1002/glia.22776] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/20/2014] [Indexed: 02/02/2023]
Abstract
The K(+) channel expression pattern of microglia strongly depends on the cells' microenvironment and has been recognized as a sensitive marker of the cells' functional state. While numerous studies have been performed on microglia in vitro, our knowledge about microglial K(+) channels and their regulation in vivo is limited. Here, we have investigated K(+) currents of microglia in striatum, neocortex and entorhinal cortex of young adult and aged mice. Although almost all microglial cells exhibited inward rectifier K(+) currents upon membrane hyperpolarization, their mean current density was significantly enhanced in aged mice compared with that determined in young adult mice. Some microglial cells additionally exhibited outward rectifier K(+) currents in response to depolarizing voltage pulses. In aged mice, microglial outward rectifier K(+) current density was significantly larger than in young adult mice due to the increased number of aged microglial cells expressing these channels. Aged dystrophic microglia exhibited outward rectifier K(+) currents more frequently than aged ramified microglia. The majority of microglial cells expressed functional BK-type, but not IK- or SK-type, Ca(2+) -activated K(+) channels, while no differences were found in their expression levels between microglia of young adult and aged mice. Neither microglial K(+) channel pattern nor K(+) channel expression levels differed markedly between the three brain regions investigated. It is concluded that age-related changes in microglial phenotype are accompanied by changes in the expression of microglial voltage-activated, but not Ca(2+) -activated, K(+) channels.
Collapse
Affiliation(s)
- Tom Schilling
- Institute for Infection and Immunity, St. George's, University of London; Cranmer Terrace, London, SW17 0RE, United Kingdom
| | | |
Collapse
|
31
|
Ferreira R, Lively S, Schlichter LC. IL-4 type 1 receptor signaling up-regulates KCNN4 expression, and increases the KCa3.1 current and its contribution to migration of alternative-activated microglia. Front Cell Neurosci 2014; 8:183. [PMID: 25071444 PMCID: PMC4077126 DOI: 10.3389/fncel.2014.00183] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/14/2014] [Indexed: 01/05/2023] Open
Abstract
The Ca2+-activated K+ channel, KCa3.1 (KCNN4/IK1/SK4), contributes to “classical,” pro-inflammatory activation of microglia, and KCa3.1 blockers have improved the outcome in several rodent models of CNS damage. For instance, blocking KCa3.1 with TRAM-34 rescued retinal ganglion neurons after optic nerve damage in vivo and, reduced p38 MAP kinase activation, production of reactive oxygen and nitrogen species, and neurotoxicity by microglia in vitro. In pursuing the therapeutic potential of KCa3.1 blockers, it is crucial to assess KCa3.1 contributions to other microglial functions and activation states, especially the IL-4-induced “alternative” activation state that can counteract pro-inflammatory states. We recently found that IL-4 increases microglia migration – a crucial function in the healthy and damaged CNS – and that KCa3.1 contributes to P2Y2 receptor-stimulated migration. Here, we discovered that KCa3.1 is greatly increased in alternative-activated rat microglia and then contributes to an enhanced migratory capacity. IL-4 up-regulated KCNN4 mRNA (by 6 h) and greatly increased the KCa3.1 current by 1 day, and this required de novo protein synthesis. The increase in current was sustained for at least 6 days. IL-4 increased microglial migration and this was reversed by blocking KCa3.1 with TRAM-34. A panel of inhibitors of signal-transduction mediators was used to analyze contributions of IL-4-related signaling pathways. Induction of KCNN4 mRNA and KCa3.1 current was mediated specifically through IL-4 binding to the type I receptor and, surprisingly, it required JAK3, Ras/MEK/ERK signaling and the transcription factor, activator protein-1, rather than JAK2, STAT6, or phosphatidylinositol 3-kinase.The same receptor subtype and pathway were required for the enhanced KCa3.1-dependent migration. In providing the first direct signaling link between an IL-4 receptor, expression and roles of an ion channel, this study also highlights the potential importance of KCa3.1 in alternative-activated microglia.
Collapse
Affiliation(s)
- Roger Ferreira
- Genes and Development Division, Toronto Western Research Institute, University Health Network Toronto, ON, Canada ; Department of Physiology, University of Toronto Toronto, ON, Canada
| | - Starlee Lively
- Genes and Development Division, Toronto Western Research Institute, University Health Network Toronto, ON, Canada
| | - Lyanne C Schlichter
- Genes and Development Division, Toronto Western Research Institute, University Health Network Toronto, ON, Canada ; Department of Physiology, University of Toronto Toronto, ON, Canada
| |
Collapse
|
32
|
Abstract
Microglia are brain resident immune cells and their functions are implicated in both the normal and diseased brain. Microglia express a plethora of ion channels, including K(+) channels, Na(+) channels, TRP channels, Cl(-) channels, and proton channels. These ion channels play critical roles in microglial proliferation, migration, and production/release of cytokines, chemokines, and neurotoxic or neurotrophic substances. Among microglial ion channels, the voltage-gated proton channel HV1 is a recently cloned ion channel that rapidly removes protons from depolarized cytoplasm and is highly expressed in the immune system. However, the function of microglial HV1 in the brain is poorly understood. Recent studies showed that HV1 is selectively expressed in microglia but not neurons in the brain. At the cellular level, microglial HV1 regulates intracellular pH and aids in NADPH oxidase-dependent generation of reactive oxygen species. In a mouse model of middle cerebral artery occlusion, microglial HV1 contributes to neuronal cell death and ischemic brain damage. This review discusses the discovery, properties, regulation, and pathophysiology of microglial HV1 proton channel in the brain.
Collapse
Affiliation(s)
- Long-Jun Wu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| |
Collapse
|
33
|
Arnoux I, Hoshiko M, Sanz Diez A, Audinat E. Paradoxical effects of minocycline in the developing mouse somatosensory cortex. Glia 2013; 62:399-410. [PMID: 24357027 DOI: 10.1002/glia.22612] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/07/2013] [Accepted: 11/22/2013] [Indexed: 01/09/2023]
Abstract
Minocycline, a tetracycline derivative, is known to exert neuroprotective effects unrelated to its antimicrobial action. In particular, minocycline prevents microglial activation in pathological conditions and consequently reduces the production of proinflammatory factors contributing to the propagation of diseases. Accumulative evidence indicates that microglial cells contribute to the maturation of neuronal and synaptic networks during the normal development of the central nervous system (CNS) and that perinatal inflammation is a known risk factor for brain lesions. Although minocycline has been used to infer microglia functions during development, mechanisms by which this tetracycline derivative affect the immature CNS have not been analyzed in detail. In this study, we demonstrate that minocycline administration during the first postnatal week of development has paradoxical effects on microglia phenotype and on neuronal survival in the mouse somatosensory cortex. Using a combination of immunohistochemistry and electrophysiology, we show that intraperitoneal injections of minocycline between postnatal days 6 and 8 affect distribution, morphology, and functional properties of microglia cells of the whisker-related barrel cortex, leading to the development of a phenotype resembling that of microglia activated in pathological conditions. Minocyline also induced a massive cell death that developed faster than changes in microglia phenotype, suggesting that the latter is a consequence of the former. Finally, cell death and microglial activation were not observed when minocycline treatment was postponed by only 2 days (i.e., between postnatal days 8 and 10). These observations call into question the use of tetracycline derivatives during CNS development to study microglia or to reduce perinatal inflammation.
Collapse
Affiliation(s)
- Isabelle Arnoux
- INSERM U603, Paris, France; CNRS UMR 8154, Paris, France; Paris Descartes University, Paris, France
| | | | | | | |
Collapse
|
34
|
Peng Y, Lu K, Li Z, Zhao Y, Wang Y, Hu B, Xu P, Shi X, Zhou B, Pennington M, Chandy KG, Tang Y. Blockade of Kv1.3 channels ameliorates radiation-induced brain injury. Neuro Oncol 2013; 16:528-39. [PMID: 24305723 DOI: 10.1093/neuonc/not221] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Tumors affecting the head, neck, and brain account for significant morbidity and mortality. The curative efficacy of radiotherapy for these tumors is well established, but radiation carries a significant risk of neurologic injury. So far, neuroprotective therapies for radiation-induced brain injury are still limited. In this study we demonstrate that Stichodactyla helianthus (ShK)-170, a specific inhibitor of the voltage-gated potassium (Kv)1.3 channel, protected mice from radiation-induced brain injury. METHODS Mice were treated with ShK-170 for 3 days immediately after brain irradiation. Radiation-induced brain injury was assessed by MRI scans and a Morris water maze. Pathophysiological change of the brain was measured by immunofluorescence. Gene and protein expressions of Kv1.3 and inflammatory factors were measured by quantitative real-time PCR, reverse transcription PCR, ELISA assay, and western blot analyses. Kv currents were recorded in the whole-cell configuration of the patch-clamp technique. RESULTS Radiation increased Kv1.3 mRNA and protein expression in microglia. Genetic silencing of Kv1.3 by specific short interference RNAs or pharmacological blockade with ShK-170 suppressed radiation-induced production of the proinflammatory factors interleukin-6, cyclooxygenase-2, and tumor necrosis factor-α by microglia. ShK-170 also inhibited neurotoxicity mediated by radiation-activated microglia and promoted neurogenesis by increasing the proliferation of neural progenitor cells. CONCLUSIONS The therapeutic effect of ShK-170 is mediated by suppression of microglial activation and microglia-mediated neurotoxicity and enhanced neurorestoration by promoting proliferation of neural progenitor cells.
Collapse
Affiliation(s)
- Ying Peng
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China (Y.P., K.L., Z.L., Y.W., B.H., P.X., X.S., Y.T.); Department of Neurosurgery, Shanghai 10th People's Hospital, Tongji University, Shanghai, China (Y.Z., B.Z.); Peptides International, Louisville, Kentucky (M.P.); Department of Physiology and Biophysics, University of California, Irvine, Irvine, California (K.G.C.)
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Potent and multiple regulatory actions of microglial glucocorticoid receptors during CNS inflammation. Cell Death Differ 2013; 20:1546-57. [PMID: 24013726 DOI: 10.1038/cdd.2013.108] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 05/18/2013] [Accepted: 06/21/2013] [Indexed: 01/11/2023] Open
Abstract
In CNS, glucocorticoids (GCs) activate both GC receptor (GR) and mineralocorticoid receptor (MR), whereas GR is widely expressed, the expression of MR is restricted. However, both are present in the microglia, the resident macrophages of the brain and their activation can lead to pro- or anti-inflammatory effects. We have therefore addressed the specific functions of GR in microglia. In mice lacking GR in macrophages/microglia and in the absence of modifications in MR expression, intraparenchymal injection of lipopolysaccharide (LPS) activating Toll-like receptor 4 signaling pathway resulted in exacerbated cellular lesion, neuronal and axonal damage. Global inhibition of GR by RU486 pre-treatment revealed that microglial GR is the principal mediator preventing neuronal degeneration triggered by lipopolysaccharide (LPS) and contributes with GRs of other cell types to the protection of non-neuronal cells. In vivo and in vitro data show GR functions in microglial differentiation, proliferation and motility. Interestingly, microglial GR also abolishes the LPS-induced delayed outward rectifier currents by downregulating Kv1.3 expression known to control microglia proliferation and oxygen radical production. Analysis of GR transcriptional function revealed its powerful negative control of pro-inflammatory effectors as well as upstream inflammatory activators. Finally, we analyzed the role of GR in chronic unpredictable mild stress and aging, both known to prime or sensitize microglia in vivo. We found that microglial GR suppresses rather than mediates the deleterious effects of stress or aging on neuronal survival. Overall, the results show that microglial GR acts on several key processes limiting pro-inflammatory actions of activated microglia.
Collapse
|
36
|
Arnoux I, Hoshiko M, Mandavy L, Avignone E, Yamamoto N, Audinat E. Adaptive phenotype of microglial cells during the normal postnatal development of the somatosensory "Barrel" cortex. Glia 2013; 61:1582-94. [PMID: 23893820 DOI: 10.1002/glia.22503] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 03/08/2013] [Indexed: 11/06/2022]
Abstract
Accumulative evidence indicates that microglial cells influence the normal development of central nervous system (CNS) synapses. Yet, the functional properties of microglia in relation with synapse development remain unclear. We recently showed that in layer 4 of the whisker-related barrel field of the mouse somatosensory cortex, microglial cells are recruited only after postnatal day (P)5 in the center of the barrels where thalamo-cortical synapses are concentrated and begin their maturation. In the present study, we analyzed the phenotype of microglia during this developmental process. We show that between P5 and P7 microglial cells acquire a more ramified morphology with a smaller soma, they express classical markers of microglia (Iba1, CD11b, and CD68) but never markers of activation (Mac-2 and MHCII) and rarely the proliferation marker Ki67. Electrophysiological recordings in acute cortical slices showed that at P5 a proportion of layer 4 microglia transiently express voltage-dependant potassium currents of the delayed rectifier family, mostly mediated by Kv1.3 subunits, which are usually expressed by activated microglia under pathological conditions. This proportion of cells with rectifying properties doubles between P5 and P6, in concomitance with the beginning of microglia invasion of the barrel centers. Finally, analysis of the responses mediated by purinergic receptors indicated that a higher percentage of rectifying microglia expressed functional P2Y6 and P2Y12 receptors, as compared with nonrectifying cells, whereas all cells expressed functional P2X7 receptors. Our results indicate that during normal cortical development distinct microglia properties mature differentially, some of them being exquisitely influenced by the local environment of the maturating neuronal network.
Collapse
Affiliation(s)
- Isabelle Arnoux
- Inserm, U603, Paris, France; CNRS UMR, 8154, Paris, France; Paris Descartes University, Paris, France
| | | | | | | | | | | |
Collapse
|
37
|
Ulmann L, Levavasseur F, Avignone E, Peyroutou R, Hirbec H, Audinat E, Rassendren F. Involvement of P2X4 receptors in hippocampal microglial activation after status epilepticus. Glia 2013; 61:1306-19. [PMID: 23828736 DOI: 10.1002/glia.22516] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 04/02/2013] [Accepted: 04/05/2013] [Indexed: 11/09/2022]
Abstract
Within the central nervous system, functions of the ATP-gated receptor-channel P2X4 (P2X4R) are still poorly understood, yet P2X4R activation in neurons and microglia coincides with high or pathological neuronal activities. In this study, we investigated the potential involvement of P2X4R in microglial functions in a model of kainate (KA)-induced status epilepticus (SE). We found that SE was associated with an induction of P2X4R expression in the hippocampus, mostly localized in activated microglial cells. In P2X4R-deficient mice, behavioral responses during KA-induced SE were unaltered. However, 48h post SE specific features of microglial activation, such as cell recruitment and upregulation of voltage-dependent potassium channels were impaired in P2X4R-deficient mice, whereas the expression and function of other microglial purinergic receptors remained unaffected. Consistent with the role of P2X4R in activity-dependent degenerative processes, the CA1 area was partially protected from SE-induced neuronal death in P2X4R-deficient mice compared with wild-type animals. Our findings demonstrate that P2X4Rs are brought into play during neuronal hyperexcitability and that they control specific aspects of microglial activation. Our results also suggest that P2X4Rs contribute to excitotoxic damages by regulating microglial activation.
Collapse
Affiliation(s)
- Lauriane Ulmann
- Institut de Génomique Fonctionnelle, Labex ICST, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Université Montpellier, Montpellier, France.
| | | | | | | | | | | | | |
Collapse
|
38
|
Liu J, Xu P, Collins C, Liu H, Zhang J, Keblesh JP, Xiong H. HIV-1 Tat protein increases microglial outward K(+) current and resultant neurotoxic activity. PLoS One 2013; 8:e64904. [PMID: 23738010 PMCID: PMC3667810 DOI: 10.1371/journal.pone.0064904] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/19/2013] [Indexed: 11/19/2022] Open
Abstract
Microglia plays a crucial role in the pathogenesis of HIV-1-associated neurocognitive disorders. Increasing evidence indicates the voltage-gated potassium (Kv) channels are involved in the regulation of microglia function, prompting us to hypothesize Kv channels may also be involved in microglia-mediated neurotoxic activity in HIV-1-infected brain. To test this hypothesis, we investigated the involvement of Kv channels in the response of microglia to HIV-1 Tat protein. Treatment of rat microglia with HIV-1 Tat protein (200 ng/ml) resulted in pro-inflammatory microglial activation, as indicated by increases in TNF-α, IL-1β, reactive oxygen species, and nitric oxide, which were accompanied by enhanced outward K(+) current and Kv1.3 channel expression. Suppression of microglial Kv1.3 channel activity, either with Kv1.3 channel blockers Margatoxin, 5-(4-Phenoxybutoxy)psoralen, or broad-spectrum K(+) channel blocker 4-Aminopyridine, or by knockdown of Kv1.3 expression via transfection of microglia with Kv1.3 siRNA, was found to abrogate the neurotoxic activity of microglia resulting from HIV-1 Tat exposure. Furthermore, HIV-1 Tat-induced neuronal apoptosis was attenuated with the application of supernatant collected from K(+) channel blocker-treated microglia. Lastly, the intracellular signaling pathways associated with Kv1.3 were investigated and enhancement of microglial Kv1.3 was found to correspond with an increase in Erk1/2 mitogen-activated protein kinase activation. These data suggest targeting microglial Kv1.3 channels may be a potential new avenue of therapy for inflammation-mediated neurological disorders.
Collapse
Affiliation(s)
- Jianuo Liu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail: (JL); (HX)
| | - Peng Xu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Cory Collins
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Han Liu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jingdong Zhang
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - James P. Keblesh
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Huangui Xiong
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail: (JL); (HX)
| |
Collapse
|
39
|
Mast TG, Fadool DA. Mature and precursor brain-derived neurotrophic factor have individual roles in the mouse olfactory bulb. PLoS One 2012; 7:e31978. [PMID: 22363780 PMCID: PMC3283713 DOI: 10.1371/journal.pone.0031978] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 01/16/2012] [Indexed: 11/18/2022] Open
Abstract
Background Sensory deprivation induces dramatic morphological and neurochemical changes in the olfactory bulb (OB) that are largely restricted to glomerular and granule layer interneurons. Mitral cells, pyramidal-like neurons, are resistant to sensory-deprivation-induced changes and are associated with the precursor to brain-derived neurotrophic factor (proBDNF); here, we investigate its unknown function in the adult mouse OB. Principal Findings As determined using brain-slice electrophysiology in a whole-cell configuration, brain-derived neurotrophic factor (BDNF), but not proBDNF, increased mitral cell excitability. BDNF increased mitral cell action potential firing frequency and decreased interspike interval in response to current injection. In a separate set of experiments, intranasal delivery of neurotrophic factors to awake, adult mice was performed to induce sustained interneuron neurochemical changes. ProBDNF, but not BDNF, increased activated-caspase 3 and reduced tyrosine hydroxylase immunoreactivity in OB glomerular interneurons. In a parallel set of experiments, short-term sensory deprivation produced by unilateral naris occlusion generated an identical phenotype. Conclusions Our results indicate that only mature BDNF increases mitral cell excitability whereas proBDNF remains ineffective. Our demonstration that proBDNF activates an apoptotic marker in vivo is the first for any proneurotrophin and establishes a role for proBDNF in a model of neuronal plasticity.
Collapse
Affiliation(s)
- Thomas Gerald Mast
- Department of Biological Science, The Florida State University, Tallahassee, Florida, United States of America.
| | | |
Collapse
|
40
|
Liu J, Xu C, Chen L, Xu P, Xiong H. Involvement of Kv1.3 and p38 MAPK signaling in HIV-1 glycoprotein 120-induced microglia neurotoxicity. Cell Death Dis 2012; 3:e254. [PMID: 22258405 PMCID: PMC3270274 DOI: 10.1038/cddis.2011.140] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Inflammatory responses mediated by activated microglia play a pivotal role in the pathogenesis of human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders. Studies on identification of specific targets to control microglia activation and resultant neurotoxic activity are imperative. Increasing evidence indicate that voltage-gated K+ (Kv) channels are involved in the regulation of microglia functionality. In this study, we investigated Kv1.3 channels in the regulation of neurotoxic activity mediated by HIV-1 glycoprotein 120 (gp120)-stimulated rat microglia. Our results showed treatment of microglia with gp120 increased the expression levels of Kv1.3 mRNA and protein. In parallel, whole-cell patch-clamp studies revealed that gp120 enhanced microglia Kv1.3 current, which was blocked by margatoxin, a Kv1.3 blocker. The association of gp120 enhancement of Kv1.3 current with microglia neurotoxicity was demonstrated by experimental results that blocking microglia Kv1.3 attenuated gp120-associated microglia production of neurotoxins and neurotoxicity. Knockdown of Kv1.3 gene by transfection of microglia with Kv1.3-siRNA abrogated gp120-associated microglia neurotoxic activity. Further investigation unraveled an involvement of p38 MAPK in gp120 enhancement of microglia Kv1.3 expression and resultant neurotoxic activity. These results suggest not only a role Kv1.3 may have in gp120-associated microglia neurotoxic activity, but also a potential target for the development of therapeutic strategies.
Collapse
Affiliation(s)
- J Liu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
| | | | | | | | | |
Collapse
|
41
|
Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
Collapse
|
42
|
Abstract
It is well admitted now that gliosis participates in epileptogenesis, particularly in symptomatic focal epilepsies, like temporal lobe epilepsy. Indeed, astrocytic and microglial activation was shown to release numerous inflammatory factors that modify neuronal excitability or contribute to neuronal loss. These redundant processes maintain chronic epilepsy. However, other sources of inflammation exist. Several studies pointed out the epileptogenicity of blood-brain barrier disruption due to the leakage of leukocytes and serum proteins, triggering inflammatory and immune responses which disturb the neuronal environment. Recently, it was proposed that peripheral inflammation plays a key-role in epilepsy, mainly mediated by circulating cytokines which promote leukocyte extravasation.
Collapse
Affiliation(s)
- Mireille Lerner-Natoli
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U661, UM1, UM2, 141 rue de la Cardonille, 34094 Montpellier Cedex 9, France.
| |
Collapse
|
43
|
Xu C, Liu J, Chen L, Liang S, Fujii N, Tamamura H, Xiong H. HIV-1 gp120 enhances outward potassium current via CXCR4 and cAMP-dependent protein kinase A signaling in cultured rat microglia. Glia 2011; 59:997-1007. [PMID: 21438014 DOI: 10.1002/glia.21171] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 02/23/2011] [Indexed: 11/09/2022]
Abstract
Microglia are critical cells in mediating the pathophysiology of neurodegenerative disorders such as HIV-associated neurocognitive disorders. We hypothesize that HIV-1 glycoprotein 120 (gp120) activates microglia by enhancing outward K(+) currents, resulting in microglia secretion of neurotoxins, consequent neuronal dysfunction, and death. To test this hypothesis, we studied the effects of gp120 on outward K(+) current in cultured rat microglia. Application of gp120 enhanced outward K(+) current in a dose-dependent manner, which was blocked by voltage-gated K(+) (K(v) ) channel blockers. Western blot analysis revealed that gp120 produced an elevated expression of K(v) channel proteins. Examination of activation and inactivation of outward K(+) currents showed that gp120 shifted membrane potentials for activation and steady-state inactivation. The gp120-associated enhancement of outward K(+) current was blocked by either a CXCR4 receptor antagonist T140 or a specific protein kinase A (PKA) inhibitor H89, suggesting the involvement of chemokine receptor CXCR4 and PKA in gp120-mediated enhancement of outward K(+) current. Biological significance of gp120-induced enhancement of microglia outward K(+) current was demonstrated by experimental results showing the neurotoxic activity of gp120-stimulated microglia, evaluated by TUNEL staining and MTT assay, significantly attenuated by K(v) channel blockers. Taken together, these results suggest that gp120 induces microglia neurotoxic activity by enhancing microglia outward K(+) current and that microglia K(v) channels may function as a potential target for the development of therapeutic strategies.
Collapse
Affiliation(s)
- Changshui Xu
- Neurophysiology Laboratory, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
Felipe A, Soler C, Comes N. Kv1.5 in the immune system: the good, the bad, or the ugly? Front Physiol 2010; 1:152. [PMID: 21423392 PMCID: PMC3059964 DOI: 10.3389/fphys.2010.00152] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/28/2010] [Indexed: 11/13/2022] Open
Abstract
For the last 20 years, knowledge of the physiological role of voltage-dependent potassium channels (Kv) in the immune system has grown exponentially. Leukocytes express a limited repertoire of Kv channels, which contribute to the membrane potential. These proteins are involved in the immune response and are therefore considered good pharmacological targets. Although there is a clear consensus about the physiological relevance of Kv1.3, the expression and the role of Kv1.5 are controversial. However, recent reports indicate that certain heteromeric Kv1.3/Kv1.5 associations may provide insight on Kv1.5. Here, we summarize what is known about this issue and highlight the role of Kv1.5 partnership interactions that could be responsible for this debate. The Kv1.3/Kv1.5 heterotetrameric composition of the channel and their possible differential associations with accessory regulatory proteins warrant further investigation.
Collapse
Affiliation(s)
- Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina, Universitat de Barcelona Barcelona, Spain.
| | | | | |
Collapse
|
45
|
Eder C. Ion channels in monocytes and microglia / brain macrophages: Promising therapeutic targets for neurological diseases. J Neuroimmunol 2010; 224:51-5. [DOI: 10.1016/j.jneuroim.2010.05.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 05/04/2010] [Indexed: 10/19/2022]
|