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Obot P, Cibelli A, Pan J, Velíšek L, Velíšková J, Scemes E. Pannexin1 Mediates Early-Life Seizure-Induced Social Behavior Deficits. ASN Neuro 2024; 16:2371164. [PMID: 39024558 DOI: 10.1080/17590914.2024.2371164] [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: 01/11/2024] [Accepted: 04/11/2024] [Indexed: 07/20/2024] Open
Abstract
There is a high co-morbidity between childhood epilepsy and autism spectrum disorder (ASD), with age of seizure onset being a critical determinant of behavioral outcomes. The interplay between these comorbidities has been investigated in animal models with results showing that the induction of seizures at early post-natal ages leads to learning and memory deficits and to autistic-like behavior in adulthood. Modifications of the excitation/inhibition (glutamate/GABA, ATP/adenosine) balance that follows early-life seizures (ELS) are thought to be the physiological events that underlie neuropsychiatric and neurodevelopmental disorders. Although alterations in purinergic/adenosinergic signaling have been implicated in seizures and ASD, it is unknown whether the ATP release channels, Pannexin1 (Panx1), contribute to ELS-induced behavior changes. To tackle this question, we used the ELS-kainic acid model in transgenic mice with global and cell type specific deletion of Panx1 to evaluate whether these channels were involved in behavioral deficits that occur later in life. Our studies show that ELS results in Panx1 dependent social behavior deficits and also in poor performance in a spatial memory test that does not involve Panx1. These findings provide support for a link between ELS and adult behavioral deficits. Moreover, we identify neuronal and not astrocyte Panx1 as a potential target to specifically limit astrogliosis and social behavioral deficits resultant from early-life seizures.
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Affiliation(s)
- Price Obot
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
| | - Antonio Cibelli
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Jian Pan
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
| | - Libor Velíšek
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
- Department of Neurology, New York Medical College, Valhalla, New York, USA
- Department of Pediatrics, New York Medical College, Valhalla, New York, USA
| | - Jana Velíšková
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
- Department of Neurology, New York Medical College, Valhalla, New York, USA
- Department of Obstetrics and Gynecology, New York Medical College, Valhalla, New York, USA
| | - Eliana Scemes
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, USA
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2
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Tichauer JE, Lira M, Cerpa W, Orellana JA, Sáez JC, Rovegno M. Inhibition of astroglial hemichannels prevents synaptic transmission decline during spreading depression. Biol Res 2024; 57:39. [PMID: 38867288 PMCID: PMC11167948 DOI: 10.1186/s40659-024-00519-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/28/2024] [Indexed: 06/14/2024] Open
Abstract
BACKGROUND Spreading depression (SD) is an intriguing phenomenon characterized by massive slow brain depolarizations that affect neurons and glial cells. This phenomenon is repetitive and produces a metabolic overload that increases secondary damage. However, the mechanisms associated with the initiation and propagation of SD are unknown. Multiple lines of evidence indicate that persistent and uncontrolled opening of hemichannels could participate in the pathogenesis and progression of several neurological disorders including acute brain injuries. Here, we explored the contribution of astroglial hemichannels composed of connexin-43 (Cx43) or pannexin-1 (Panx1) to SD evoked by high-K+ stimulation in brain slices. RESULTS Focal high-K+ stimulation rapidly evoked a wave of SD linked to increased activity of the Cx43 and Panx1 hemichannels in the brain cortex, as measured by light transmittance and dye uptake analysis, respectively. The activation of these channels occurs mainly in astrocytes but also in neurons. More importantly, the inhibition of both the Cx43 and Panx1 hemichannels completely prevented high K+-induced SD in the brain cortex. Electrophysiological recordings also revealed that Cx43 and Panx1 hemichannels critically contribute to the SD-induced decrease in synaptic transmission in the brain cortex and hippocampus. CONCLUSIONS Targeting Cx43 and Panx1 hemichannels could serve as a new therapeutic strategy to prevent the initiation and propagation of SD in several acute brain injuries.
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Affiliation(s)
- Juan E Tichauer
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Matías Lira
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Waldo Cerpa
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Juan C Sáez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.
| | - Maximiliano Rovegno
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
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3
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García-Rodríguez C, Duarte Y, Ardiles ÁO, Sáez JC. The antiseizure medication valproate increases hemichannel activity found in brain cells, which could worsen disease outcomes. J Neurochem 2024; 168:1045-1059. [PMID: 38291613 DOI: 10.1111/jnc.16062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 02/01/2024]
Abstract
Glial cells play relevant roles in neuroinflammation caused by epilepsy. Elevated hemichannel (HC) activity formed by connexins (Cxs) or pannexin1 (Panx1) largely explains brain dysfunctions commonly caused by neuroinflammation. Glia express HCs formed by Cxs 43, 30, or 26, while glia and neurons both express HCs formed by Panx1. Cx43 HCs allow for the influx of Ca2+, which promotes glial reactivity, enabling the release of the gliotransmitters that contribute to neuronal over-stimulation. Valproate (VPA), an antiseizure medication, has pleiotropic actions on neuronal molecular targets, and their action on glial cell HCs remains elusive. We used HeLa cells transfected with Cx43, Cx30, Cx26, or Panx1 to determine the effect of VPA on HC activity in the brain. VPA slightly increased HC activity under basal conditions, but significantly enhanced it in cells pre-exposed to conditions that promoted HC activity. Furthermore, VPA increased ATP release through Cx43 HCs. The increased HC activity caused by VPA was resistant to washout, being consistent with in silico studies, which predicted the binding site for VPA and Cx43, as well as for Panx1 HCs on the intracellular side, suggesting that VPA first enters through HCs, after which their activity increases.
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Affiliation(s)
- Claudia García-Rodríguez
- Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Yorley Duarte
- Facultad de Ciencias de la Vida, Center for Bioinformatics and Integrative Biology, Universidad Andrés Bello, Santiago, Chile
| | - Álvaro O Ardiles
- Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Medicina, Escuela de Medicina, Universidad de Valparaíso, Valparaíso, Chile
| | - Juan C Sáez
- Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
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4
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Hussain N, Apotikar A, Pidathala S, Mukherjee S, Burada AP, Sikdar SK, Vinothkumar KR, Penmatsa A. Cryo-EM structures of pannexin 1 and 3 reveal differences among pannexin isoforms. Nat Commun 2024; 15:2942. [PMID: 38580658 PMCID: PMC10997603 DOI: 10.1038/s41467-024-47142-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 03/19/2024] [Indexed: 04/07/2024] Open
Abstract
Pannexins are single-membrane large-pore channels that release ions and ATP upon activation. Three isoforms of pannexins 1, 2, and 3, perform diverse cellular roles and differ in their pore lining residues. In this study, we report the cryo-EM structure of pannexin 3 at 3.9 Å and analyze its structural differences with pannexin isoforms 1 and 2. The pannexin 3 vestibule has two distinct chambers and a wider pore radius in comparison to pannexins 1 and 2. We further report two cryo-EM structures of pannexin 1, with pore substitutions W74R/R75D that mimic the pore lining residues of pannexin 2 and a germline mutant of pannexin 1, R217H at resolutions of 3.2 Å and 3.9 Å, respectively. Substitution of cationic residues in the vestibule of pannexin 1 results in reduced ATP interaction propensities to the channel. The germline mutant R217H in transmembrane helix 3 (TM3), leads to a partially constricted pore, reduced ATP interaction and weakened voltage sensitivity. The study compares the three pannexin isoform structures, the effects of substitutions of pore and vestibule-lining residues and allosteric effects of a pathological substitution on channel structure and function thereby enhancing our understanding of this vital group of ATP-release channels.
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Affiliation(s)
- Nazia Hussain
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Ashish Apotikar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Shabareesh Pidathala
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
- St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sourajit Mukherjee
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
- Department of Chemistry, The University of Chicago, Chicago, USA
| | - Ananth Prasad Burada
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Sujit Kumar Sikdar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Kutti R Vinothkumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, 560065, India
| | - Aravind Penmatsa
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India.
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5
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Sanchez‐Pupo RE, Finch GA, Johnston DE, Craig H, Abdo R, Barr K, Kerfoot S, Dagnino L, Penuela S. Global pannexin 1 deletion increases tumor-infiltrating lymphocytes in the BRAF/Pten mouse melanoma model. Mol Oncol 2024; 18:969-987. [PMID: 38327091 PMCID: PMC10994229 DOI: 10.1002/1878-0261.13596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/20/2023] [Accepted: 01/18/2024] [Indexed: 02/09/2024] Open
Abstract
Immunotherapies for malignant melanoma seek to boost the anti-tumoral response of CD8+ T cells, but have a limited patient response rate, in part due to limited tumoral immune cell infiltration. Genetic or pharmacological inhibition of the pannexin 1 (PANX1) channel-forming protein is known to decrease melanoma cell tumorigenic properties in vitro and ex vivo. Here, we crossed Panx1 knockout (Panx1-/-) mice with the inducible melanoma model BrafCA, PtenloxP, Tyr::CreERT2 (BPC). We found that deleting the Panx1 gene in mice does not reduce BRAF(V600E)/Pten-driven primary tumor formation or improve survival. However, tumors in BPC-Panx1-/- mice exhibited a significant increase in the infiltration of CD8+ T lymphocytes, with no changes in the expression of early T-cell activation marker CD69, lymphocyte activation gene 3 protein (LAG-3) checkpoint receptor, or programmed cell death ligand-1 (PD-L1) in tumors when compared to the BPC-Panx1+/+ genotype. Our results suggest that, although Panx1 deletion does not overturn the aggressive BRAF/Pten-driven melanoma progression in vivo, it does increase the infiltration of effector immune T-cell populations in the tumor microenvironment. We propose that PANX1-targeted therapy could be explored as a strategy to increase tumor-infiltrating lymphocytes to boost anti-tumor immunity.
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Affiliation(s)
| | - Garth A. Finch
- Department of Anatomy and Cell BiologyWestern UniversityLondonCanada
| | | | - Heather Craig
- Department of Microbiology and ImmunologyWestern UniversityLondonCanada
| | - Rober Abdo
- Department of Anatomy and Cell BiologyWestern UniversityLondonCanada
| | - Kevin Barr
- Department of Anatomy and Cell BiologyWestern UniversityLondonCanada
| | - Steven Kerfoot
- Department of Microbiology and ImmunologyWestern UniversityLondonCanada
| | - Lina Dagnino
- Department of Physiology and PharmacologyWestern UniversityLondonCanada
- Division of Experimental Oncology, Department of Oncology, Schulich School of Medicine and DentistryWestern UniversityLondonCanada
| | - Silvia Penuela
- Department of Anatomy and Cell BiologyWestern UniversityLondonCanada
- Division of Experimental Oncology, Department of Oncology, Schulich School of Medicine and DentistryWestern UniversityLondonCanada
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6
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Díaz F, Aguilar F, Wellmann M, Martorell A, González-Arancibia C, Chacana-Véliz L, Negrón-Oyarzo I, Chávez AE, Fuenzalida M, Nualart F, Sotomayor-Zárate R, Bonansco C. Enhanced Astrocyte Activity and Excitatory Synaptic Function in the Hippocampus of Pentylenetetrazole Kindling Model of Epilepsy. Int J Mol Sci 2023; 24:14506. [PMID: 37833953 PMCID: PMC10572460 DOI: 10.3390/ijms241914506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/12/2023] [Accepted: 09/17/2023] [Indexed: 10/15/2023] Open
Abstract
Epilepsy is a chronic condition characterized by recurrent spontaneous seizures. The interaction between astrocytes and neurons has been suggested to play a role in the abnormal neuronal activity observed in epilepsy. However, the exact way astrocytes influence neuronal activity in the epileptogenic brain remains unclear. Here, using the PTZ-induced kindling mouse model, we evaluated the interaction between astrocyte and synaptic function by measuring astrocytic Ca2+ activity, neuronal excitability, and the excitatory/inhibitory balance in the hippocampus. Compared to control mice, hippocampal slices from PTZ-kindled mice displayed an increase in glial fibrillary acidic protein (GFAP) levels and an abnormal pattern of intracellular Ca2+-oscillations, characterized by an increased frequency of prolonged spontaneous transients. PTZ-kindled hippocampal slices also showed an increase in the E/I ratio towards excitation, likely resulting from an augmented release probability of excitatory inputs without affecting inhibitory synapses. Notably, the alterations in the release probability seen in PTZ-kindled slices can be recovered by reducing astrocyte hyperactivity with the reversible toxin fluorocitrate. This suggests that astroglial hyper-reactivity enhances excitatory synaptic transmission, thereby impacting the E/I balance in the hippocampus. Altogether, our findings support the notion that abnormal astrocyte-neuron interactions are pivotal mechanisms in epileptogenesis.
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Affiliation(s)
- Franco Díaz
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
- Escuela de Ciencias de la Salud, Universidad Viña del Mar, Viña del Mar 2580022, Chile
- Programa de Magíster en Ciencias Biológicas mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Freddy Aguilar
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
- Programa de Magíster en Ciencias Biológicas mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Mario Wellmann
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
- Programa de Magíster en Ciencias Biológicas mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Andrés Martorell
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
- Programa de Magíster en Ciencias Biológicas mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Escuela de Fonoaudiología, Facultad de Salud, Universidad Santo Tomás, Viña del Mar 2561780, Chile
| | - Camila González-Arancibia
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
| | - Lorena Chacana-Véliz
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
| | - Ignacio Negrón-Oyarzo
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
| | - Andrés E. Chávez
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile;
| | - Marco Fuenzalida
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
| | - Francisco Nualart
- Laboratory of Neurobiology and Stem Cells, NeuroCellT, Department of Cellular Biology, Faculty of Biological Sciences, University of Concepcion, Concepción 4070386, Chile;
- Center for Advanced Microscopy CMA BIOBIO, Faculty of Biological Sciences, University of Concepcion, Concepción 4070386, Chile
| | - Ramón Sotomayor-Zárate
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
| | - Christian Bonansco
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile; (F.D.); (F.A.); (M.W.); (A.M.); (C.G.-A.); (L.C.-V.); (I.N.-O.); (M.F.)
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7
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García-Rodríguez C, Mujica P, Illanes-González J, López A, Vargas C, Sáez JC, González-Jamett A, Ardiles ÁO. Probenecid, an Old Drug with Potential New Uses for Central Nervous System Disorders and Neuroinflammation. Biomedicines 2023; 11:1516. [PMID: 37371611 DOI: 10.3390/biomedicines11061516] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 06/29/2023] Open
Abstract
Probenecid is an old uricosuric agent used in clinics to treat gout and reduce the renal excretion of antibiotics. In recent years, probenecid has gained attention due to its ability to interact with membrane proteins such as TRPV2 channels, organic anion transporters, and pannexin 1 hemichannels, which suggests new potential therapeutic utilities in medicine. Some current functions of probenecid include their use as an adjuvant to increase the bioavailability of several drugs in the Central Nervous System (CNS). Numerous studies also suggest that this drug has important neuroprotective, antiepileptic, and anti-inflammatory properties, as evidenced by their effect against neurological and neurodegenerative diseases. In these studies, the use of probenecid as a Panx1 hemichannel blocker to reduce neuroinflammation is highlighted since neuroinflammation is a major trigger for diverse CNS alterations. Although the clinical use of probenecid has declined over the years, advances in its use in preclinical research indicate that it may be useful to improve conventional therapies in the psychiatric field where the drugs used have a low bioavailability, either because of a deficient passage through the blood-brain barrier or a high efflux from the CNS or also a high urinary clearance. This review summarizes the history, pharmacological properties, and recent research uses of probenecid and discusses its future projections as a potential pharmacological strategy to intervene in neurodegeneration as an outcome of neuroinflammation.
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Affiliation(s)
- Claudia García-Rodríguez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Paula Mujica
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Javiera Illanes-González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Araceli López
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Camilo Vargas
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Juan C Sáez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Álvaro O Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Escuela de Medicina, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2341386, Chile
- Centro Interdisciplinario de Estudios en Salud, Facultad de Medicina, Universidad de Valparaíso, Viña del Mar 2540064, Chile
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8
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Baracaldo-Santamaría D, Corrales-Hernández MG, Ortiz-Vergara MC, Cormane-Alfaro V, Luque-Bernal RM, Calderon-Ospina CA, Cediel-Becerra JF. Connexins and Pannexins: Important Players in Neurodevelopment, Neurological Diseases, and Potential Therapeutics. Biomedicines 2022; 10:2237. [PMID: 36140338 PMCID: PMC9496069 DOI: 10.3390/biomedicines10092237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
Cell-to-cell communication is essential for proper embryonic development and its dysfunction may lead to disease. Recent research has drawn attention to a new group of molecules called connexins (Cxs) and pannexins (Panxs). Cxs have been described for more than forty years as pivotal regulators of embryogenesis; however, the exact mechanism by which they provide this regulation has not been clearly elucidated. Consequently, Cxs and Panxs have been linked to congenital neurodegenerative diseases such as Charcot-Marie-Tooth disease and, more recently, chronic hemichannel opening has been associated with adult neurodegenerative diseases (e.g., Alzheimer's disease). Cell-to-cell communication via gap junctions formed by hexameric assemblies of Cxs, known as connexons, is believed to be a crucial component in developmental regulation. As for Panxs, despite being topologically similar to Cxs, they predominantly seem to form channels connecting the cytoplasm to the extracellular space and, despite recent research into Panx1 (Pannexin 1) expression in different regions of the brain during the embryonic phase, it has been studied to a lesser degree. When it comes to the nervous system, Cxs and Panxs play an important role in early stages of neuronal development with a wide span of action ranging from cellular migration during early stages to neuronal differentiation and system circuitry formation. In this review, we describe the most recent available evidence regarding the molecular and structural aspects of Cx and Panx channels, their role in neurodevelopment, congenital and adult neurological diseases, and finally propose how pharmacological modulation of these channels could modify the pathogenesis of some diseases.
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Affiliation(s)
- Daniela Baracaldo-Santamaría
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - María Gabriela Corrales-Hernández
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Maria Camila Ortiz-Vergara
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Valeria Cormane-Alfaro
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Ricardo-Miguel Luque-Bernal
- Anatomy and Embriology Units, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Carlos-Alberto Calderon-Ospina
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
- GENIUROS Research Group, Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Juan-Fernando Cediel-Becerra
- Histology and Embryology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
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9
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Whyte-Fagundes P, Taskina D, Safarian N, Zoidl C, Carlen PL, Donaldson LW, Zoidl GR. Panx1 channels promote both anti- and pro-seizure-like activities in the zebrafish via p2rx7 receptors and ATP signaling. Commun Biol 2022; 5:472. [PMID: 35585187 PMCID: PMC9117279 DOI: 10.1038/s42003-022-03356-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
The molecular mechanisms of excitation/inhibition imbalances promoting seizure generation in epilepsy patients are not fully understood. Evidence suggests that Pannexin1 (Panx1), an ATP release channel, modulates the excitability of the brain. In this report, we performed electrophysiological, behavioral, and molecular phenotyping experiments on zebrafish larvae bearing genetic or pharmacological knockouts of Panx1a and Panx1b channels, each homologous to human PANX1. When Panx1a function is lost, or both channels are under pharmacological blockade, seizures with ictal-like events and seizure-like locomotion are reduced in the presence of pentylenetetrazol. Transcriptome profiling by RNA-seq demonstrates a spectrum of distinct metabolic and cell signaling states which correlate with the loss of Panx1a. Furthermore, the pro- and anticonvulsant activities of both Panx1 channels affect ATP release and involve the purinergic receptor P2rx7. Our findings suggest a subfunctionalization of Panx1 enabling dual roles in seizures, providing a unique and comprehensive perspective to understanding seizure mechanisms in the context of this channel.
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Affiliation(s)
- Paige Whyte-Fagundes
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada.
| | - Daria Taskina
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Nickie Safarian
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Christiane Zoidl
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada
- Department of Medicine, Physiology and BME, University of Toronto, 399 Bathurst St., 5w442, Toronto, ON, M5T 2S8, Canada
| | | | - Georg R Zoidl
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada.
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10
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Endogenous pannexin1 channels form functional intercellular cell-cell channels with characteristic voltage-dependent properties. Proc Natl Acad Sci U S A 2022; 119:e2202104119. [PMID: 35486697 PMCID: PMC9171361 DOI: 10.1073/pnas.2202104119] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pannexin1 is a glycoprotein that has been shown to form functional plasma membrane channels and mediate many cellular signaling pathways. However, the formation and function of pannexin1-based intercellular cell–cell channels in mammalian cells and vertebrate tissue is a question of substantial debate. This work provides robust electrophysiological evidence to demonstrate that endogenously expressed human pannexin1 forms cell–cell channels and lays the groundwork for studying a potential new type of electrical synapses between many mammalian cell types that endogenously express pannexin1. The occurrence of intercellular channels formed by pannexin1 has been challenged for more than a decade. Here, we provide an electrophysiological characterization of exogenous human pannexin1 (hPanx1) cell–cell channels expressed in HeLa cells knocked out for connexin45. The observed hPanx1 cell–cell channels show two phenotypes: O-state and S-state. The former displayed low transjunctional voltage (Vj) sensitivity and single-channel conductance of ∼175 pS, with a substate of ∼35 pS; the latter showed a peculiar dynamic asymmetry in Vj dependence and single-channel conductance identical to the substate conductance of the O-state. S-state hPanx1 cell–cell channels were also identified between TC620 cells, a human oligodendroglioma cell line that endogenously expresses hPanx1. In these cells, dye and electrical coupling increased with temperature and were strongly reduced after hPanx1 expression was knocked down by small interfering RNA or inhibited with Panx1 mimetic inhibitory peptide. Moreover, cell–cell coupling was augmented when hPanx1 levels were increased with a doxycycline-inducible expression system. Application of octanol, a connexin gap junction (GJ) channel inhibitor, was not sufficient to block electrical coupling between HeLa KO Cx45-hPanx1 or TC620 cell pairs. In silico studies suggest that several arginine residues inside the channel pore may be neutralized by hydrophobic interactions, allowing the passage of DAPI, consistent with dye coupling observed between TC620 cells. These findings demonstrate that endogenously expressed hPanx1 forms intercellular cell–cell channels and their unique properties resemble those described in innexin-based GJ channels. Since Panx1 is ubiquitously expressed, finding conditions to recognize Panx1 cell–cell channels in different cell types might require special attention.
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11
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Breton VL, Aquilino MS, Repudi S, Saleem A, Mylvaganam S, Abu-Swai S, Bardakjian BL, Aqeilan RI, Carlen PL. Altered neocortical oscillations and cellular excitability in an in vitro Wwox knockout mouse model of epileptic encephalopathy. Neurobiol Dis 2021; 160:105529. [PMID: 34634460 PMCID: PMC8609180 DOI: 10.1016/j.nbd.2021.105529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/24/2021] [Accepted: 10/07/2021] [Indexed: 12/02/2022] Open
Abstract
Loss of function mutations of the WW domain-containing oxidoreductase (WWOX) gene are associated with severe and fatal drug-resistant pediatric epileptic encephalopathy. Epileptic seizures are typically characterized by neuronal hyperexcitability; however, the specific contribution of WWOX to that hyperexcitability has yet to be investigated. Using a mouse model of neuronal Wwox-deletion that exhibit spontaneous seizures, in vitro whole-cell and field potential electrophysiological characterization identified spontaneous bursting activity in the neocortex, a marker of the underlying network hyperexcitability. Spectral analysis of the neocortical bursting events highlighted increased phase-amplitude coupling, and a propagation from layer II/III to layer V. These bursts were NMDAR and gap junction dependent. In layer II/III pyramidal neurons, Wwox knockout mice demonstrated elevated amplitude of excitatory post-synaptic currents, whereas the frequency and amplitude of inhibitory post-synaptic currents were reduced, as compared to heterozygote and wild-type littermate controls. Furthermore, these neurons were depolarized and demonstrated increased action potential frequency, sag current, and post-inhibitory rebound. These findings suggest WWOX plays an essential role in balancing neocortical excitability and provide insight towards developing therapeutics for those suffering from WWOX disorders.
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Affiliation(s)
- Vanessa L Breton
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada.
| | - Mark S Aquilino
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada.
| | - Srinivasarao Repudi
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Afifa Saleem
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Shanthini Mylvaganam
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada
| | - Sara Abu-Swai
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Berj L Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Rami I Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
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12
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Ding Z, Guo S, Luo L, Zheng Y, Gan S, Kang X, Wu X, Zhu S. Emerging Roles of Microglia in Neuro-vascular Unit: Implications of Microglia-Neurons Interactions. Front Cell Neurosci 2021; 15:706025. [PMID: 34712121 PMCID: PMC8546170 DOI: 10.3389/fncel.2021.706025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/10/2021] [Indexed: 12/20/2022] Open
Abstract
Microglia, which serve as the defensive interface of the nervous system, are activated in many neurological diseases. Their role as immune responding cells has been extensively studied in the past few years. Recent studies have demonstrated that neuronal feedback can be shaped by the molecular signals received and sent by microglia. Altered neuronal activity or synaptic plasticity leads to the release of various communication messages from neurons, which in turn exert effects on microglia. Research on microglia-neuron communication has thus expanded from focusing only on neurons to the neurovascular unit (NVU). This approach can be used to explore the potential mechanism of neurovascular coupling across sophisticated receptor systems and signaling cascades in health and disease. However, it remains unclear how microglia-neuron communication happens in the brain. Here, we discuss the functional contribution of microglia to synapses, neuroimmune communication, and neuronal activity. Moreover, the current state of knowledge of bidirectional control mechanisms regarding interactions between neurons and microglia are reviewed, with a focus on purinergic regulatory systems including ATP-P2RY12R signaling, ATP-adenosine-A1Rs/A2ARs, and the ATP-pannexin 1 hemichannel. This review aims to organize recent studies to highlight the multifunctional roles of microglia within the neural communication network in health and disease.
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Affiliation(s)
- Zhe Ding
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shaohui Guo
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lihui Luo
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yueying Zheng
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuyuan Gan
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xianhui Kang
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaomin Wu
- Department of Anesthesiology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Shengmei Zhu
- Department of Anesthesiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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13
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Dossi E, Rouach N. Pannexin 1 channels and ATP release in epilepsy: two sides of the same coin : The contribution of pannexin-1, connexins, and CALHM ATP-release channels to purinergic signaling. Purinergic Signal 2021; 17:533-548. [PMID: 34495463 DOI: 10.1007/s11302-021-09818-2] [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: 04/23/2021] [Accepted: 08/08/2021] [Indexed: 11/29/2022] Open
Abstract
Purinergic signaling mediated by ATP and its metabolites contributes to various brain physiological processes as well as to several pathological conditions, including neurodegenerative and neurological disorders, such as epilepsy. Among the different ATP release pathways, pannexin 1 channels represent one of the major conduits being primarily activated in pathological contexts. Investigations on in vitro and in vivo models of epileptiform activity and seizures in mice and human tissues revealed pannexin 1 involvement in aberrant network activity and epilepsy, and highlighted that pannexin 1 exerts a complex role. Pannexin 1 can indeed either sustain seizures through release of ATP that can directly activate purinergic receptors, or tune down epileptic activity via ATP-derived adenosine that decreases neuronal excitability. Interestingly, in-depth analysis of the literature unveils that this dichotomy is only apparent, as it depends on the model of seizure induction and the type of evoked epileptiform activity, two factors that can differentially activate pannexin 1 channels and trigger distinct intracellular signaling cascades. Here, we review the general properties and ATP permeability of pannexin 1 channels, and discuss their impact on acute epileptiform activity and chronic epilepsy according to the regime of activity and disease state. These data pave the way for the development of new antiepileptic strategies selectively targeting pannexin 1 channels in a context-dependent manner.
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Affiliation(s)
- Elena Dossi
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé Et de la Recherche Médicale U1050, Collège de France, Labex Memolife, Université PSL, Paris, France.
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé Et de la Recherche Médicale U1050, Collège de France, Labex Memolife, Université PSL, Paris, France.
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14
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Seo JH, Dalal MS, Contreras JE. Pannexin-1 Channels as Mediators of Neuroinflammation. Int J Mol Sci 2021; 22:ijms22105189. [PMID: 34068881 PMCID: PMC8156193 DOI: 10.3390/ijms22105189] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 02/06/2023] Open
Abstract
Neuroinflammation is a major component of central nervous system (CNS) injuries and neurological diseases, including Alzheimer’s disease, multiple sclerosis, neuropathic pain, and brain trauma. The activation of innate immune cells at the damage site causes the release of pro-inflammatory cytokines and chemokines, which alter the functionality of nearby tissues and might mediate the recruitment of leukocytes to the injury site. If this process persists or is exacerbated, it prevents the adequate resolution of the inflammation, and ultimately enhances secondary damage. Adenosine 5′ triphosphate (ATP) is among the molecules released that trigger an inflammatory response, and it serves as a chemotactic and endogenous danger signal. Extracellular ATP activates multiple purinergic receptors (P2X and P2Y) that have been shown to promote neuroinflammation in a variety of CNS diseases. Recent studies have shown that Pannexin-1 (Panx1) channels are the principal conduits of ATP release from dying cells and innate immune cells in the brain. Herein, we review the emerging evidence that directly implicates Panx-1 channels in the neuroinflammatory response in the CNS.
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Affiliation(s)
- Joon Ho Seo
- Department of Neurology and Nash Family, Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine, Mount Sinai, New York, NY 10029, USA;
| | - Miloni S. Dalal
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA;
| | - Jorge E. Contreras
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA;
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
- Correspondence: ; Tel.: +1-530-754-2770
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15
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Obot P, Velíšek L, Velíšková J, Scemes E. The Contribution of Astrocyte and Neuronal Panx1 to Seizures Is Model and Brain Region Dependent. ASN Neuro 2021; 13:17590914211007273. [PMID: 33910381 PMCID: PMC8718119 DOI: 10.1177/17590914211007273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pannexin1 (Panx1) is an ATP release channel expressed in neurons and astrocytes that plays important roles in CNS physiology and pathology. Evidence for the involvement of Panx1 in seizures includes the reduction of epileptiform activity and ictal discharges following Panx1 channel blockade or deletion. However, very little is known about the relative contribution of astrocyte and neuronal Panx1 channels to hyperexcitability. To this end, mice with global and cell type specific deletion of Panx1 were used in one in vivo and two in vitro seizure models. In the low-Mg2+ in vitro model, global deletion but not cell-type specific deletion of Panx1 reduced the frequency of epileptiform discharges. This reduced frequency of discharges did not impact the overall power spectra obtained from local field potentials. In the in vitro KA model, in contrast, global or cell type specific deletion of Panx1 did not affect the frequency of discharges, but reduced the overall power spectra. EEG recordings following KA-injection in vivo revealed that although global deletion of Panx1 did not affect the onset of status epilepticus (SE), SE onset was delayed in mice lacking neuronal Panx1 and accelerated in mice lacking astrocyte Panx1. EEG power spectral analysis disclosed a Panx1-dependent cortical region effect; while in the occipital region, overall spectral power was reduced in all three Panx1 genotypes; in the frontal cortex, the overall power was not affected by deletion of Panx1. Together, our results show that the contribution of Panx1 to ictal activity is model, cell-type and brain region dependent.
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Affiliation(s)
- Price Obot
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States
| | - Libor Velíšek
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States.,Department of Neurology, New York Medical College, Valhalla, New York, United States.,Department of Pediatrics, New York Medical College, Valhalla, New York, United States
| | - Jana Velíšková
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States.,Department of Neurology, New York Medical College, Valhalla, New York, United States.,Department of Obstetrics & Gynecology, New York Medical College, Valhalla, New York, United States
| | - Eliana Scemes
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States
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16
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Südkamp N, Shchyglo O, Manahan-Vaughan D. Absence of Pannexin 1 Stabilizes Hippocampal Excitability After Intracerebral Treatment With Aβ (1-42) and Prevents LTP Deficits in Middle-Aged Mice. Front Aging Neurosci 2021; 13:591735. [PMID: 33796018 PMCID: PMC8007872 DOI: 10.3389/fnagi.2021.591735] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 02/18/2021] [Indexed: 01/02/2023] Open
Abstract
Beta-amyloid protein [Aβ(1-42)] plays an important role in the disease progress and pathophysiology of Alzheimer's disease (AD). Membrane properties and neuronal excitability are altered in the hippocampus of transgenic AD mouse models that overexpress amyloid precursor protein. Although gap junction hemichannels have been implicated in the early pathogenesis of AD, to what extent Pannexin channels contribute to Aβ(1-42)-mediated brain changes is not yet known. In this study we, therefore, investigated the involvement of Pannexin1 (Panx1) channels in Aβ-mediated changes of neuronal membrane properties and long-term potentiation (LTP) in an animal model of AD. We conducted whole-cell patch-clamp recordings in CA1 pyramidal neurons 1 week after intracerebroventricular treatments of adult wildtype (wt) and Panx1 knockout (Panx1-ko) mice with either oligomeric Aβ(1-42), or control peptide. Panx1-ko hippocampi treated with control peptide exhibited increased neuronal excitability compared to wt. In addition, action potential (AP) firing frequency was higher in control Panx1-ko slices compared to wt. Aβ-treatment reduced AP firing frequency in both cohorts. But in Aβ-treated wt mice, spike frequency adaptation was significantly enhanced, when compared to control wt and to Aβ-treated Panx1-ko mice. Assessment of hippocampal LTP revealed deficits in Aβ-treated wt compared to control wt. By contrast, Panx1-ko exhibited LTP that was equivalent to LTP in control ko hippocampi. Taken together, our data show that in the absence of Pannexin1, hippocampi are more resistant to the debilitating effects of oligomeric Aβ. Both Aβ-mediated impairments in spike frequency adaptation and in LTP that occur in wt animals, are ameliorated in Panx1-ko mice. These results suggest that Panx1 contributes to early changes in hippocampal neuronal and synaptic function that are triggered by oligomeric Aβ.
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Affiliation(s)
- Nicolina Südkamp
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
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17
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Insights into Potential Targets for Therapeutic Intervention in Epilepsy. Int J Mol Sci 2020; 21:ijms21228573. [PMID: 33202963 PMCID: PMC7697405 DOI: 10.3390/ijms21228573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.
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