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Luo Y, Zheng S, Xiao W, Zhang H, Li Y. Pannexins in the musculoskeletal system: new targets for development and disease progression. Bone Res 2024; 12:26. [PMID: 38705887 PMCID: PMC11070431 DOI: 10.1038/s41413-024-00334-8] [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: 12/08/2023] [Revised: 03/04/2024] [Accepted: 04/01/2024] [Indexed: 05/07/2024] Open
Abstract
During cell differentiation, growth, and development, cells can respond to extracellular stimuli through communication channels. Pannexin (Panx) family and connexin (Cx) family are two important types of channel-forming proteins. Panx family contains three members (Panx1-3) and is expressed widely in bone, cartilage and muscle. Although there is no sequence homology between Panx family and Cx family, they exhibit similar configurations and functions. Similar to Cxs, the key roles of Panxs in the maintenance of physiological functions of the musculoskeletal system and disease progression were gradually revealed later. Here, we seek to elucidate the structure of Panxs and their roles in regulating processes such as osteogenesis, chondrogenesis, and muscle growth. We also focus on the comparison between Cx and Panx. As a new key target, Panxs expression imbalance and dysfunction in muscle and the therapeutic potentials of Panxs in joint diseases are also discussed.
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Affiliation(s)
- Yan Luo
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Department of Clinical Medicine, Xiangya Medicine School, Central South University, Changsha, Hunan, 410008, China
| | - Shengyuan Zheng
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Department of Clinical Medicine, Xiangya Medicine School, Central South University, Changsha, Hunan, 410008, China
| | - Wenfeng Xiao
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Hang Zhang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
| | - Yusheng Li
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
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2
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van Megen WH, van Houtert TJ, Bos C, Peters DJM, de Baaij JHF, Hoenderop JGJ. Inhibition of pannexin-1 does not restore electrolyte balance in precystic Pkd1 knockout mice. Physiol Rep 2024; 12:e15956. [PMID: 38561249 PMCID: PMC10984814 DOI: 10.14814/phy2.15956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/12/2024] [Accepted: 02/13/2024] [Indexed: 04/04/2024] Open
Abstract
Mutations in PKD1 and PKD2 cause autosomal dominant polycystic kidney disease (ADPKD), which is characterized by the formation of fluid-filled cysts in the kidney. In a subset of ADPKD patients, reduced blood calcium (Ca2+) and magnesium (Mg2+) concentrations are observed. As cystic fluid contains increased ATP concentrations and purinergic signaling reduces electrolyte reabsorption, we hypothesized that inhibiting ATP release could normalize blood Ca2+ and Mg2+ levels in ADPKD. Inducible kidney-specific Pkd1 knockout mice (iKsp-Pkd1-/-) exhibit hypocalcemia and hypomagnesemia in a precystic stage and show increased expression of the ATP-release channel pannexin-1. Therefore, we administered the pannexin-1 inhibitor brilliant blue-FCF (BB-FCF) every other day from Day 3 to 28 post-induction of Pkd1 gene inactivation. On Day 29, both serum Ca2+ and Mg2+ concentrations were reduced in iKsp-Pkd1-/- mice, while urinary Ca2+ and Mg2+ excretion was similar between the genotypes. However, serum and urinary levels of Ca2+ and Mg2+ were unaltered by BB-FCF treatment, regardless of genotype. BB-FCF did significantly decrease gene expression of the ion channels Trpm6 and Trpv5 in both control and iKsp-Pkd1-/- mice. Finally, no renoprotective effects of BB-FCF treatment were observed in iKsp-Pkd1-/- mice. Thus, administration of BB-FCF failed to normalize serum Ca2+ and Mg2+ levels.
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Affiliation(s)
- Wouter H. van Megen
- Department of Medical BiosciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Teun J. van Houtert
- Department of Medical BiosciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Caro Bos
- Department of Medical BiosciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Dorien J. M. Peters
- Department of Human GeneticsLeiden University Medical CenterLeidenThe Netherlands
| | - Jeroen H. F. de Baaij
- Department of Medical BiosciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Joost G. J. Hoenderop
- Department of Medical BiosciencesRadboud University Medical CenterNijmegenThe Netherlands
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3
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Wang J, Mim C, Dahll G, Barro-Soria R. A metastasis-associated Pannexin1 mutant (Panx1 1-89 ) forms a minimalist ATP release channel. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584732. [PMID: 38559162 PMCID: PMC10980048 DOI: 10.1101/2024.03.12.584732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
A truncated form of the ATP release channel pannexin 1 (Panx1), Panx1 1-89 , is enriched in metastatic breast cancer cells and has been proposed to mediate metastatic cell survival by increasing ATP release through mechanosensitive Panx1 channels. However, whether Panx1 1-89 on its own (without the presence of wtPanx1) mediates ATP release has not been tested. Here, we show that Panx1 1-89 by itself can form a constitutively active membrane channel, capable of releasing ATP even in the absence of wild type Panx1. Our biophysical characterization reveals that most basic structure-function features of the channel pore are conserved in the truncated Panx1 1-89 peptide. Thus, augmenting extracellular potassium ion concentrations enhances Panx1 1-89 -mediated conductance. Moreover, despite the severe truncation, Panx1 1-89 retains the sensitivity to most of wtPanx1 channel inhibitors and can thus be targeted. Therefore, Panx1 blockers have the potential to be of therapeutic value to combat metastatic cell survival. Our study not only elucidates a mechanism for ATP release from cancer cells, but it also supports that the Panx1 1-89 mutant should facilitate structure-function analysis of Panx1 channels.
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4
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Cibelli A, Dohare P, Spray DC, Scemes E. Differential activation of mouse and human Panx1 channel variants. PLoS One 2023; 18:e0295710. [PMID: 38100403 PMCID: PMC10723736 DOI: 10.1371/journal.pone.0295710] [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: 09/06/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023] Open
Abstract
Pannexins are ubiquitously expressed in human and mouse tissues. Pannexin 1 (Panx1), the most thoroughly characterized member of this family, forms plasmalemmal membrane channels permeable to relatively large molecules, such as ATP. Although human and mouse Panx1 amino acid sequences are conserved in the presently known regulatory sites involved in trafficking and modulation of the channel, differences are reported in the N- and C-termini of the protein, and the mechanisms of channel activation by different stimuli remain controversial. Here we used a neuroblastoma cell line to study the activation properties of endogenous mPanx1 and exogenously expressed hPanx1. Dye uptake and electrophysiological recordings revealed that in contrast to mouse Panx1, the human ortholog is insensitive to stimulation with high extracellular [K+] but responds similarly to activation of the purinergic P2X7 receptor. The two most frequent Panx1 polymorphisms found in the human population, Q5H (rs1138800) and E390D (rs74549886), exogenously expressed in Panx1-null N2a cells revealed that regarding P2X7 receptor mediated Panx1 activation, the Q5H mutant is a gain of function whereas the E390D mutant is a loss of function variant. Collectively, we demonstrate differences in the activation between human and mouse Panx1 orthologs and suggest that these differences may have translational implications for studies where Panx1 has been shown to have significant impact.
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Affiliation(s)
- Antonio Cibelli
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Preeti Dohare
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - David C. Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Eliana Scemes
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
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5
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O'Donnell BL, Penuela S. Skin in the game: pannexin channels in healthy and cancerous skin. Biochem J 2023; 480:1929-1949. [PMID: 38038973 DOI: 10.1042/bcj20230176] [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: 09/29/2023] [Revised: 11/15/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023]
Abstract
The skin is a highly organized tissue composed of multiple layers and cell types that require coordinated cell to cell communication to maintain tissue homeostasis. In skin cancer, this organized structure and communication is disrupted, prompting the malignant transformation of healthy cells into melanoma, basal cell carcinoma or squamous cell carcinoma tumours. One such family of channel proteins critical for cellular communication is pannexins (PANX1, PANX2, PANX3), all of which are present in the skin. These heptameric single-membrane channels act as conduits for small molecules and ions like ATP and Ca2+ but have also been shown to have channel-independent functions through their interacting partners or action in signalling pathways. Pannexins have diverse roles in the skin such as in skin development, aging, barrier function, keratinocyte differentiation, inflammation, and wound healing, which were discovered through work with pannexin knockout mice, organotypic epidermis models, primary cells, and immortalized cell lines. In the context of cutaneous cancer, PANX1 is present at high levels in melanoma tumours and functions in melanoma carcinogenesis, and both PANX1 and PANX3 expression is altered in non-melanoma skin cancer. PANX2 has thus far not been implicated in any skin cancer. This review will discuss pannexin isoforms, structure, trafficking, post-translational modifications, interactome, and channel activity. We will also outline the expression, localization, and function of pannexin channels within the diverse cell types of the epidermis, dermis, hypodermis, and adnexal structures of the skin, and how these properties are exploited or abrogated in instances of skin cancer.
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Affiliation(s)
- Brooke L O'Donnell
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
- Department of Oncology, Division of Experimental Oncology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
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6
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van Megen WH, Canki E, Wagenaar VHA, van Waes CRMM, Peters DJM, Van Asbeck-Van der Wijst J, Hoenderop JGJ. Fluid shear stress stimulates ATP release without regulating purinergic gene expression in the renal inner medullary collecting duct. FASEB J 2023; 37:e23232. [PMID: 37819258 DOI: 10.1096/fj.202301434r] [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: 07/14/2023] [Revised: 09/14/2023] [Accepted: 09/19/2023] [Indexed: 10/13/2023]
Abstract
In the kidney, the flow rate of the pro-urine through the renal tubules is highly variable. The tubular epithelial cells sense these variations in pro-urinary flow rate in order to regulate various physiological processes, including electrolyte reabsorption. One of the mechanosensitive pathways activated by flow is the release of ATP, which can then act as a autocrine or paracrine factor. Increased ATP release is observed in various kidney diseases, among others autosomal dominant polycystic kidney disease (ADPKD). However, the mechanisms underlying flow-induced ATP release in the collecting duct, especially in the inner medullary collecting duct, remain understudied. Using inner medullary collecting duct 3 (IMCD3) cells in a microfluidic setup, we show here that administration of a high flow rate for 1 min results in an increased ATP release compared to a lower flow rate. Although the ATP release channel pannexin-1 contributed to flow-induced ATP release in Pkd1-/- IMCD3 cells, it did not in wildtype IMCD3 cells. In addition, flow application increased the expression of the putative ATP release channel connexin-30.3 (CX30.3) in wildtype and Pkd1-/- IMCD3 cells. However, CX30.3 knockout IMCD3 cells exhibited a similar flow-induced ATP release as wildtype IMCD3 cells, suggesting that CX30.3 does not drive flow-induced ATP release in wildtype IMDC3 cells. Collectively, our results show differential mechanisms underlying flow-induced ATP release in wildtype and Pkd1-/- IMCD3 cells and further strengthen the link between ADPKD and pannexin-1-dependent ATP release.
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Affiliation(s)
- Wouter H van Megen
- Department of Medical Biosciences, Radboudumc, Nijmegen, The Netherlands
| | - Esra Canki
- Department of Medical Biosciences, Radboudumc, Nijmegen, The Netherlands
| | - Vera H A Wagenaar
- Department of Medical Biosciences, Radboudumc, Nijmegen, The Netherlands
| | | | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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7
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Caufriez A, Lamouroux A, Martin C, Iaculli D, Ince Ergüç E, Gozalbes R, Mayan MD, Kwak BR, Tabernilla A, Vinken M, Ballet S. Determination of structural features that underpin the pannexin1 channel inhibitory activity of the peptide 10Panx1. Bioorg Chem 2023; 138:106612. [PMID: 37210827 DOI: 10.1016/j.bioorg.2023.106612] [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: 03/07/2023] [Revised: 04/29/2023] [Accepted: 05/11/2023] [Indexed: 05/23/2023]
Abstract
Pannexin1 channels facilitate paracrine communication and are involved in a broad spectrum of diseases. Attempts to find appropriate pannexin1 channel inhibitors that showcase target-selective properties and in vivo applicability remain nonetheless scarce. However, a promising lead candidate, the ten amino acid long peptide mimetic 10Panx1 (H-Trp1-Arg2-Gln3-Ala4-Ala5-Phe6-Val7-Asp8-Ser9-Tyr10-OH), has shown potential as a pannexin1 channel inhibitor in both in vitro and in vivo studies. Nonetheless, structural optimization is critical for clinical use. One of the main hurdles to overcome along the optimization process consists of subduing the low biological stability (10Panx1 t1/2 = 2.27 ± 0.11 min). To tackle this issue, identification of important structural features within the decapeptide structure is warranted. For this reason, a structure-activity relationship study was performed to proteolytically stabilize the sequence. Through an Alanine scan, this study demonstrated that the side chains of Gln3 and Asp8 are crucial for 10Panx1's channel inhibitory capacity. Guided by plasma stability experiments, scissile amide bonds were identified and stabilized, while extracellular adenosine triphosphate release experiments, indicative of pannexin1 channel functionality, allowed to enhance the in vitro inhibitory capacity of 10Panx1.
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Affiliation(s)
- Anne Caufriez
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Research Group of In Vitro Toxicology and Dermato-cosmetology, Department of Pharmaceutical and Pharmacological sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Arthur Lamouroux
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Charlotte Martin
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Debora Iaculli
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Elif Ince Ergüç
- Research Group of In Vitro Toxicology and Dermato-cosmetology, Department of Pharmaceutical and Pharmacological sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Rafael Gozalbes
- ProtoQSAR SL, Centro Europeo de Empresas Innovadoras, Parque Tecnológico de Valencia, Avda. Benjamin Franklin 12, 46980 Paterna, Spain
| | - Maria D Mayan
- CellCOM Research Group, Instituto de Investigación Biomédica de A Coruña, Servizo Galego de Saúde, Universidade da Coruña, 15071 A Coruña, Spain
| | - Brenda R Kwak
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, 1211 Geneva, Switzerland
| | - Andrés Tabernilla
- Research Group of In Vitro Toxicology and Dermato-cosmetology, Department of Pharmaceutical and Pharmacological sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Mathieu Vinken
- Research Group of In Vitro Toxicology and Dermato-cosmetology, Department of Pharmaceutical and Pharmacological sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Steven Ballet
- Research Group of Organic Chemistry, Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
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8
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Sluyter R, Adriouch S, Fuller SJ, Nicke A, Sophocleous RA, Watson D. Animal Models for the Investigation of P2X7 Receptors. Int J Mol Sci 2023; 24:ijms24098225. [PMID: 37175933 PMCID: PMC10179175 DOI: 10.3390/ijms24098225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
The P2X7 receptor is a trimeric ligand-gated cation channel activated by extracellular adenosine 5'-triphosphate. The study of animals has greatly advanced the investigation of P2X7 and helped to establish the numerous physiological and pathophysiological roles of this receptor in human health and disease. Following a short overview of the P2X7 distribution, roles and functional properties, this article discusses how animal models have contributed to the generation of P2X7-specific antibodies and nanobodies (including biologics), recombinant receptors and radioligands to study P2X7 as well as to the pharmacokinetic testing of P2X7 antagonists. This article then outlines how mouse and rat models have been used to study P2X7. These sections include discussions on preclinical disease models, polymorphic P2X7 variants, P2X7 knockout mice (including bone marrow chimeras and conditional knockouts), P2X7 reporter mice, humanized P2X7 mice and P2X7 knockout rats. Finally, this article reviews the limited number of studies involving guinea pigs, rabbits, monkeys (rhesus macaques), dogs, cats, zebrafish, and other fish species (seabream, ayu sweetfish, rainbow trout and Japanese flounder) to study P2X7.
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Affiliation(s)
- Ronald Sluyter
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Sahil Adriouch
- UniRouen, INSERM, U1234, Pathophysiology, Autoimmunity, and Immunotherapy, (PANTHER), Univ Rouen Normandie, University of Rouen, F-76000 Rouen, France
| | - Stephen J Fuller
- Sydney Medical School Nepean, Faculty of Medicine and Health, The University of Sydney, Nepean Hospital, Kingswood, NSW 2750, Australia
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany
| | - Reece A Sophocleous
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Debbie Watson
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
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Koval M, Schug WJ, Isakson BE. Pharmacology of pannexin channels. Curr Opin Pharmacol 2023; 69:102359. [PMID: 36858833 PMCID: PMC10023479 DOI: 10.1016/j.coph.2023.102359] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/18/2023] [Accepted: 01/29/2023] [Indexed: 03/02/2023]
Abstract
Pannexin channels play fundamental roles in regulating inflammation and have been implicated in many diseases including hypertension, stroke, and neuropathic pain. Thus, the ability to pharmacologically block these channels is a vital component of several therapeutic approaches. Pharmacologic interrogation of model systems also provides a means to discover new roles for pannexins in cell physiology. Here, we review the state of the art for agents that can be used to block pannexin channels, with a focus on chemical pharmaceuticals and peptide mimetics that act on pannexin 1. Guidance on interpreting results obtained with pannexin pharmacologics in experimental systems is discussed, as well as strengths and caveats of different agents, including specificity and feasibility of clinical application.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wyatt J Schug
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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10
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MSCs-derived apoptotic extracellular vesicles promote muscle regeneration by inducing Pannexin 1 channel-dependent creatine release by myoblasts. Int J Oral Sci 2023; 15:7. [PMID: 36646698 PMCID: PMC9842731 DOI: 10.1038/s41368-022-00205-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 10/07/2022] [Accepted: 10/09/2022] [Indexed: 01/18/2023] Open
Abstract
Severe muscle injury is hard to heal and always results in a poor prognosis. Recent studies found that extracellular vesicle-based therapy has promising prospects for regeneration medicine, however, whether extracellular vesicles have therapeutic effects on severe muscle injury is still unknown. Herein, we extracted apoptotic extracellular vesicles derived from mesenchymal stem cells (MSCs-ApoEVs) to treat cardiotoxin induced tibialis anterior (TA) injury and found that MSCs-ApoEVs promoted muscles regeneration and increased the proportion of multinucleated cells. Besides that, we also found that apoptosis was synchronized during myoblasts fusion and MSCs-ApoEVs promoted the apoptosis ratio as well as the fusion index of myoblasts. Furthermore, we revealed that MSCs-ApoEVs increased the relative level of creatine during myoblasts fusion, which was released via activated Pannexin 1 channel. Moreover, we also found that activated Pannexin 1 channel was highly expressed on the membrane of myoblasts-derived ApoEVs (Myo-ApoEVs) instead of apoptotic myoblasts, and creatine was the pivotal metabolite involved in myoblasts fusion. Collectively, our findings firstly revealed that MSCs-ApoEVs can promote muscle regeneration and elucidated that the new function of ApoEVs as passing inter-cell messages through releasing metabolites from activated Pannexin 1 channel, which will provide new evidence for extracellular vesicles-based therapy as well as improving the understanding of new functions of extracellular vesicles.
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11
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Duy-Thanh D, Bich-Ngoc N, Van den Bossche F, Lai-Thanh N, Muller M. Discovering Novel Bioactivities of Controversial Food Additives by Means of Simple Zebrafish Embryotoxicity (ZET) Assays. TOXICS 2022; 11:8. [PMID: 36668734 PMCID: PMC9861749 DOI: 10.3390/toxics11010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/05/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
The rising concerns about controversial food additives' potential hazardous properties require extensive yet animal-minimized testing strategies. Zebrafish embryos are the ideal in vivo model representing both human and environmental health. In this study, we exposed zebrafish embryos to eight controversial food additives. Our results indicate that Sodium Benzoate is a Cat.3 aquatic toxicant, while Quinoline Yellow is a strong teratogen. At high concentrations, non-toxic chemicals induced similar phenotypes, suggesting the impact of ionic strength and the applicability of the darkened yolk phenotype as an indicator of nephrotoxicity. Three food additives showed unpredicted bioactivities on the zebrafish embryos: Brilliant Blue could weaken the embryonic yolk, Quinoline Yellow may interfere with nutrient metabolism, and Azorubine induced precocious zebrafish hatching. In conclusion, the zebrafish embryo is ideal for high throughput chemical safety and toxicity screening, allowing systematic detection of biological effects-especially those unexpected by targeted in vitro and in silico models. Additionally, our data suggest the need to reconsider the safety status of food additives Quinoline Yellow, Brilliant Blue, Sodium Benzoate, and other controversial food additives in further studies, as well as pave the way to further applications based on the newly found properties of Brilliant Blue and Azorubine.
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Affiliation(s)
- Dinh Duy-Thanh
- Laboratory for Organogenesis and Regeneration, GIGA Institute, University of Liège, 4000 Liège, Belgium
| | - Nguyen Bich-Ngoc
- LEMA, Urban and Environmental Engineering Department, University of Liège, 4000 Liège, Belgium
| | - François Van den Bossche
- Laboratory for Organogenesis and Regeneration, GIGA Institute, University of Liège, 4000 Liège, Belgium
- Molecular Physiology Research Unit, Faculty of Medicine, University of Namur, 5000 Namur, Belgium
| | - Nguyen Lai-Thanh
- Department of Cell Biology, Faculty of Biology, VNU University of Science, Hanoi 100000, Vietnam
| | - Marc Muller
- Laboratory for Organogenesis and Regeneration, GIGA Institute, University of Liège, 4000 Liège, Belgium
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12
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Mechanical Disturbance of Osteoclasts Induces ATP Release That Leads to Protein Synthesis in Skeletal Muscle through an Akt-mTOR Signaling Pathway. Int J Mol Sci 2022; 23:ijms23169444. [PMID: 36012713 PMCID: PMC9408906 DOI: 10.3390/ijms23169444] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/10/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
Abstract
Muscle and bone are tightly integrated through mechanical and biochemical signals. Osteoclasts are cells mostly related to pathological bone loss; however, they also start physiological bone remodeling. Therefore, osteoclast signals released during bone remodeling could improve both bone and skeletal muscle mass. Extracellular ATP is an autocrine/paracrine signaling molecule released by bone and muscle cells. Then, in the present work, it was hypothesized that ATP is a paracrine mediator released by osteoclasts and leads to skeletal muscle protein synthesis. RAW264.7-derived osteoclasts were co-cultured in Transwell® chambers with flexor digitorum brevis (FDB) muscle isolated from adult BalbC mice. The osteoclasts at the upper chamber were mechanically stimulated by controlled culture medium perturbation, resulting in a two-fold increase in protein synthesis in FDB muscle at the lower chamber. Osteoclasts released ATP to the extracellular medium in response to mechanical stimulation, proportional to the magnitude of the stimulus and partly dependent on the P2X7 receptor. On the other hand, exogenous ATP promoted Akt phosphorylation (S473) in isolated FDB muscle in a time- and concentration-dependent manner. ATP also induced phosphorylation of proteins downstream Akt: mTOR (S2448), p70S6K (T389) and 4E-BP1 (T37/46). Exogenous ATP increased the protein synthesis rate in FDB muscle 2.2-fold; this effect was blocked by Suramin (general P2X/P2Y antagonist), LY294002 (phosphatidylinositol 3 kinase inhibitor) and Rapamycin (mTOR inhibitor). These blockers, as well as apyrase (ATP metabolizing enzyme), also abolished the induction of FDB protein synthesis evoked by mechanical stimulation of osteoclasts in the co-culture model. Therefore, the present findings suggest that mechanically stimulated osteoclasts release ATP, leading to protein synthesis in isolated FDB muscle, by activating the P2-PI3K-Akt-mTOR pathway. These results open a new area for research and clinical interest in bone-to-muscle crosstalk in adaptive processes related to muscle use/disuse or in musculoskeletal pathologies.
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13
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Omolaoye TS, Jalaleddine N, Cardona Maya WD, du Plessis SS. Mechanisms of SARS-CoV-2 and Male Infertility: Could Connexin and Pannexin Play a Role? Front Physiol 2022; 13:866675. [PMID: 35721552 PMCID: PMC9205395 DOI: 10.3389/fphys.2022.866675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on male infertility has lately received significant attention. SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) in humans, has been shown to impose adverse effects on both the structural components and function of the testis, which potentially impact spermatogenesis. These adverse effects are partially explained by fever, systemic inflammation, oxidative stress, and an increased immune response leading to impaired blood-testis barrier. It has been well established that efficient cellular communication via gap junctions or functional channels is required for tissue homeostasis. Connexins and pannexins are two protein families that mediate autocrine and paracrine signaling between the cells and the extracellular environment. These channel-forming proteins have been shown to play a role in coordinating cellular communication in the testis and epididymis. Despite their role in maintaining a proper male reproductive milieu, their function is disrupted under pathological conditions. The involvement of these channels has been well documented in several physiological and pathological conditions and their designated function in infectious diseases. However, their role in COVID-19 and their meaningful contribution to male infertility remains to be elucidated. Therefore, this review highlights the multivariate pathophysiological mechanisms of SARS-CoV-2 involvement in male reproduction. It also aims to shed light on the role of connexin and pannexin channels in disease progression, emphasizing their unexplored role and regulation of SARS-CoV-2 pathophysiology. Finally, we hypothesize the possible involvement of connexins and pannexins in SARS-CoV-2 inducing male infertility to assist future research ideas targeting therapeutic approaches.
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Affiliation(s)
- Temidayo S. Omolaoye
- Department of Basic Sciences, College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Nour Jalaleddine
- Department of Basic Sciences, College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Walter D. Cardona Maya
- Reproduction Group, Department of Microbiology and Parasitology, Faculty of Medicine, Universidad de Antioquia, Medellin, Colombia
| | - Stefan S. du Plessis
- Department of Basic Sciences, College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
- Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
- *Correspondence: Stefan S. du Plessis,
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14
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Crocetti L, Guerrini G, Giovannoni MP, Melani F, Lamanna S, Di Cesare Mannelli L, Lucarini E, Ghelardini C, Wang J, Dahl G. New Panx-1 Blockers: Synthesis, Biological Evaluation and Molecular Dynamic Studies. Int J Mol Sci 2022; 23:4827. [PMID: 35563213 PMCID: PMC9103715 DOI: 10.3390/ijms23094827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 12/25/2022] Open
Abstract
The channel protein Panx-1 is involved in some pathologies, such as epilepsy, ischemic stroke, cancer and Parkinson's disease, as well as in neuropathic pain. These observations make Panx-1 an interesting biological target. We previously published some potent indole derivatives as Panx-1 blockers, and as continuation of the research in this field we report here the studies on additional chemical scaffolds, naphthalene and pyrazole, appropriately substituted with those functions that gave the best results as in our indole series (sulphonamide functions and one/two carboxylic groups) and in Panx-1 blockers reported in the literature (sulphonic acid). Compounds 4 and 13, the latter being an analogue of the drug Probenecid, are the most potent Panx-1 blockers obtained in this study, with I = 97% and I = 93.7% at 50 µM, respectively. Both compounds, tested in a mouse model of oxaliplatin-induced neuropathic pain, showed a similar anti-hypersensitivity profile and are able to significantly increase the mouse pain threshold 45 min after the injection of the doses of 1 nmol and 3 nmol. Finally, the molecular dynamic studies and the PCA analysis have made it possible to identify a discriminating factor able to separate active compounds from inactive ones.
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Affiliation(s)
- Letizia Crocetti
- NEUROFARBA, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy; (L.C.); (G.G.); (F.M.); (S.L.)
| | - Gabriella Guerrini
- NEUROFARBA, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy; (L.C.); (G.G.); (F.M.); (S.L.)
| | - Maria Paola Giovannoni
- NEUROFARBA, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy; (L.C.); (G.G.); (F.M.); (S.L.)
| | - Fabrizio Melani
- NEUROFARBA, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy; (L.C.); (G.G.); (F.M.); (S.L.)
| | - Silvia Lamanna
- NEUROFARBA, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy; (L.C.); (G.G.); (F.M.); (S.L.)
| | - Lorenzo Di Cesare Mannelli
- NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (L.D.C.M.); (E.L.); (C.G.)
| | - Elena Lucarini
- NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (L.D.C.M.); (E.L.); (C.G.)
| | - Carla Ghelardini
- NEUROFARBA, Pharmacology and Toxicology Section, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (L.D.C.M.); (E.L.); (C.G.)
| | - Junjie Wang
- Department of Physiology and Biophysics, University of Miami School of Medicine, 1600 N.W. 10th Avenue, Miami, FL 33136, USA; (J.W.); (G.D.)
| | - Gerhard Dahl
- Department of Physiology and Biophysics, University of Miami School of Medicine, 1600 N.W. 10th Avenue, Miami, FL 33136, USA; (J.W.); (G.D.)
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15
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Pannexin1 channels regulate mechanically stimulated but not spontaneous adenosine release. Anal Bioanal Chem 2022; 414:3781-3789. [PMID: 35381855 DOI: 10.1007/s00216-022-04047-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/22/2022] [Accepted: 03/25/2022] [Indexed: 11/01/2022]
Abstract
Fast-scan cyclic voltammetry (FSCV) is a rapid technique to measure neuromodulators, and using FSCV, two modes of rapid adenosine have been discovered. Spontaneous transients occur randomly in the brain, while mechanical stimulation also causes a rapid adenosine event. Pannexin1 channels are membrane channels that transport ions, including ATP, out of the cell where it is rapidly broken down into adenosine. Pannexin 1 channels (Panx1) have a flickering mode of rapid opening and are also mechanically stimulated. Here, we test the extent to which pannexin channels, specifically pannexin1 (Panx1) channels, are responsible for rapid adenosine events. Spontaneous adenosine release or mechanosensitive adenosine release were measured using fast-scan cyclic voltammetry in hippocampal (CA1) brain slices. In global Panx1KO mice, there is no significant difference in the frequency or concentration of spontaneous adenosine release, indicating Panx1 is not a release mechanism for spontaneous adenosine. Spontaneous adenosine frequency decreased slightly after administration of a large (100 µM) dose of carbenoxolone, a nonspecific inhibitor of many pannexin and connexin channels, suggesting other hemichannels only play a small role at most. For mechanically stimulated adenosine release, the concentration of each adenosine event significantly decreased 30% in Panx1KO mice and the frequency of stimulations that evoked adenosine also decreased. The response was similar in WT mice with carbenoxolone. Thus, Panx1 is a release mechanism for mechanically stimulated adenosine release, but not the only mechanism. These results demonstrate that pannexin channels differentially regulate rapid adenosine release and could be targeted to differentially affect mechanically stimulated adenosine due to brain damage.
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16
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Yang B, Zhong W, Gu Y, Li Y. Emerging Mechanisms and Targeted Therapy of Pyroptosis in Central Nervous System Trauma. Front Cell Dev Biol 2022; 10:832114. [PMID: 35399534 PMCID: PMC8990238 DOI: 10.3389/fcell.2022.832114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/14/2022] [Indexed: 01/31/2023] Open
Abstract
Cell death can occur in different modes, ferroptosis, pyroptosis, apoptosis, and necroptosis. Recent studies have shown that pyroptosis can be effectively regulated and that like necroptosis, pyroptosis has been regarded as a type of programmed cell death. The mechanism of its occurrence can be divided into canonical inflammasome-induced pyroptosis and noncanonical inflammasome-induced pyroptosis. In the past research, pyroptosis has been shown to be closely related to various diseases, such as tumors, neurodegenerative diseases, and central nervous system trauma, and studies have pointed out that in central nervous system trauma, pyroptosis is activated. Furthermore, these studies have shown that the inhibition of pyroptosis can play a role in protecting nerve function. In this review, we summarized the mechanisms of pyroptosis, introduce treatment strategies for targeted pyroptosis in central nervous system trauma, and proposed some issues of targeted pyroptosis in the treatment of central nervous system injury.
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Affiliation(s)
- Biao Yang
- Department of Neurosurgery, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Weijie Zhong
- Department of Neurosurgery, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Gu
- Department of Neurology, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Yi Li
- Department of Neurosurgery, Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Yi Li,
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17
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Chambers CA, Dadelahi AS, Moley CR, Olson RM, Logue CM, Skyberg JA. Nucleotide receptors mediate protection against neonatal sepsis and meningitis caused by alpha-hemolysin expressing Escherichia coli K1. FASEB J 2022; 36:e22197. [PMID: 35147989 DOI: 10.1096/fj.202101485r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/30/2021] [Accepted: 01/20/2022] [Indexed: 01/15/2023]
Abstract
Neonatal meningitis-associated Escherichia coli (NMEC) is among the leading causes of bacterial meningitis and sepsis in newborn infants. Several virulence factors have been identified as common among NMEC, and have been shown to play an important role in the development of bacteremia and/or meningitis. However, there is significant variability in virulence factor expression between NMEC isolates, and relatively little research has been done to assess the impact of variable virulence factor expression on immune cell activation and the outcome of infection. Here, we investigated the role of NMEC strain-dependent P2X receptor (P2XR) signaling on the outcome of infection in neonatal mice. We found that alpha-hemolysin (HlyA)-expressing NMEC (HlyA+ ) induced robust P2XR-dependent macrophage cell death in vitro, while HlyA- NMEC did not. P2XR-dependent cell death was inflammasome independent, suggesting an uncoupling of P2XR and inflammasome activation in the context of NMEC infection. In vivo inhibition of P2XRs was associated with increased mortality in neonatal mice infected with HlyA+ NMEC, but had no effect on the survival of neonatal mice infected with HlyA- NMEC. Furthermore, we found that P2XR-dependent protection against HlyA+ NMEC in vivo required macrophages, but not neutrophils or NLRP3. Taken together, these data suggest that HlyA+ NMEC activates P2XRs which in turn confers macrophage-dependent protection against infection in neonates. In addition, our findings indicate that strain-dependent virulence factor expression should be taken into account when studying the immune response to NMEC.
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Affiliation(s)
- Catherine A Chambers
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Alexis S Dadelahi
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Charles R Moley
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Rachel M Olson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Catherine M Logue
- Department of Population Heath, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Jerod A Skyberg
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
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18
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Design and synthesis of the first indole-based blockers of Panx-1 channel. Eur J Med Chem 2021; 223:113650. [PMID: 34174741 DOI: 10.1016/j.ejmech.2021.113650] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 06/09/2021] [Accepted: 06/12/2021] [Indexed: 10/21/2022]
Abstract
Panx-1 is a membrane channel protein involved in some pathologies such as ischemic stroke, cancer and neuropathic pain, thus representing a promising therapeutic target. We present here a study aimed at obtaining the first class of selective Panx-1 blockers, a new topic for pharmaceutical chemistry, since all compounds used so far for the study of this channel have different primary targets. Among various scaffolds analyzed, the indole nucleous emerged, whose elaboration yielded interesting Panx-1 blockers, such as the potent 5-sulfamoyl derivatives 14c and 15b (I% = 100 at 50 μM). In vivo tests performed in the mouse model of oxaliplatin-induced neuropathy, demonstrated that the hypersensitivity was completely reverted by treatment with 15b (1 nmol, administered intrathecally), suggesting a relationship between this effect and the channel blocking ability. Finally, we decided to perform a virtual screening study on compounds 5b, 6l and 14c using a recently resolved cryo-EM structure of hPanx-1 channel, to try to relate the potency of our new inhibitors.
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19
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Siu RCF, Kotova A, Timonina K, Zoidl C, Zoidl GR. Convergent NMDA receptor-Pannexin1 signaling pathways regulate the interaction of CaMKII with Connexin-36. Commun Biol 2021; 4:702. [PMID: 34103655 PMCID: PMC8187354 DOI: 10.1038/s42003-021-02230-x] [Citation(s) in RCA: 3] [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: 09/27/2020] [Accepted: 05/12/2021] [Indexed: 12/24/2022] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) binding and phosphorylation of mammalian connexin-36 (Cx36) potentiate electrical coupling. To explain the molecular mechanism of how Cx36 modifies plasticity at gap junctions, we investigated the roles of ionotropic N-methyl-D-aspartate receptors and pannexin1 (Panx1) channels in regulating Cx36 binding to CaMKII. Pharmacological interference and site-directed mutagenesis of protein interaction sites shows that NMDA receptor activation opens Cx36 channels, causing the Cx36- CaMKII binding complex to adopt a compact conformation. Ectopic Panx1 expression in a Panx1 knock-down cell line is required to restore CaMKII mediated opening of Cx36. Furthermore, blocking of Src-family kinase activation of Panx1 is sufficient to prevent the opening of Cx36 channels. Our research demonstrates that the efficacy of Cx36 channels requires convergent calcium-dependent signaling processes in which activation of ionotropic N-methyl-D-aspartate receptor, Src-family kinase, and Pannexin1 open Cx36. Our results add to the best of our knowledge a new twist to mounting evidence for molecular communication between these core components of electrical and chemical synapses.
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Affiliation(s)
- Ryan C F Siu
- Department of Biology, York University, Toronto, ON, Canada
- Center of Vision Research, York University, Toronto, ON, Canada
| | - Anna Kotova
- Department of Biology, York University, Toronto, ON, Canada
- Center of Vision Research, York University, Toronto, ON, Canada
| | - Ksenia Timonina
- Department of Biology, York University, Toronto, ON, Canada
- Center of Vision Research, York University, Toronto, ON, Canada
| | | | - Georg R Zoidl
- Department of Biology, York University, Toronto, ON, Canada.
- Center of Vision Research, York University, Toronto, ON, Canada.
- Department of Psychology, York University, Toronto, ON, Canada.
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20
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Khanna A, Sellegounder D, Kumar J, Chamoli M, Vargas M, Chinta SJ, Rane A, Nelson C, Peiris TH, Brem R, Andersen J, Lithgow G, Kapahi P. Trimethylamine modulates dauer formation, neurodegeneration, and lifespan through tyra-3/daf-11 signaling in Caenorhabditis elegans. Aging Cell 2021; 20:e13351. [PMID: 33819374 PMCID: PMC8135002 DOI: 10.1111/acel.13351] [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: 05/20/2020] [Revised: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 11/27/2022] Open
Abstract
In the nematode Caenorhabditis elegans, signals derived from bacteria in the diet, the animal's major nutrient source, can modulate both behavior and healthspan. Here we describe a dual role for trimethylamine (TMA), a human gut flora metabolite, which acts as a nutrient signal and a neurotoxin. TMA and its associated metabolites are produced by the human gut microbiome and have been suggested to serve as risk biomarkers for diabetes and cardiovascular diseases. We demonstrate that the tyramine receptor TYRA-3, a conserved G protein-coupled receptor (GPCR), is required to sense TMA and mediate its responses. TMA activates guanylyl cyclase DAF-11 signaling through TYRA-3 in amphid neurons (ASK) and ciliated neurons (BAG) to mediate food-sensing behavior. Bacterial mutants deficient in TMA production enhance dauer formation, extend lifespan, and are less preferred as a food source. Increased levels of TMA lead to neural damage in models of Parkinson's disease and shorten lifespan. Our results reveal conserved signaling pathways modulated by TMA in C. elegans that are likely to be relevant for its effects in mammalian systems.
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Affiliation(s)
- Amit Khanna
- Buck Institute for Research on Aging Novato CA USA
- Dovetail Genomics LLC Scotts Valley CA USA
| | | | | | | | | | - Shankar J. Chinta
- Buck Institute for Research on Aging Novato CA USA
- Touro University California Vallejo CA USA
| | - Anand Rane
- Buck Institute for Research on Aging Novato CA USA
| | | | | | - Rachel Brem
- Buck Institute for Research on Aging Novato CA USA
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21
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Mim C, Perkins G, Dahl G. Structure versus function: Are new conformations of pannexin 1 yet to be resolved? J Gen Physiol 2021; 153:211971. [PMID: 33835130 PMCID: PMC8042604 DOI: 10.1085/jgp.202012754] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pannexin 1 (Panx1) plays a decisive role in multiple physiological and pathological settings, including oxygen delivery to tissues, mucociliary clearance in airways, sepsis, neuropathic pain, and epilepsy. It is widely accepted that Panx1 exerts its role in the context of purinergic signaling by providing a transmembrane pathway for ATP. However, under certain conditions, Panx1 can also act as a highly selective membrane channel for chloride ions without ATP permeability. A recent flurry of publications has provided structural information about the Panx1 channel. However, while these structures are consistent with a chloride selective channel, none show a conformation with strong support for the ATP release function of Panx1. In this Viewpoint, we critically assess the existing evidence for the function and structure of the Panx1 channel and conclude that the structure corresponding to the ATP permeation pathway is yet to be determined. We also list a set of additional topics needing attention and propose ways to attain the large-pore, ATP-permeable conformation of the Panx1 channel.
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Affiliation(s)
- Carsten Mim
- Department of Biomedical Engineering and Health Systems Royal Institute of Technology, Huddinge, Sweden
| | - Guy Perkins
- National Center for Microscopy and Imaging Research, University of California, San Diego School of Medicine, La Jolla, CA
| | - Gerhard Dahl
- Department of Physiology, University of Miami School of Medicine, Miami, FL
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22
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Purinergic signaling in nervous system health and disease: Focus on pannexin 1. Pharmacol Ther 2021; 225:107840. [PMID: 33753132 DOI: 10.1016/j.pharmthera.2021.107840] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2021] [Indexed: 02/06/2023]
Abstract
Purinergic signaling encompasses the cycle of adenosine 5' triphosphate (ATP) release and its metabolism into nucleotide and nucleoside derivatives, the direct release of nucleosides, and subsequent receptor-triggered downstream intracellular pathways. Since the discovery of nerve terminal and glial ATP release into the neuropil, purinergic signaling has been implicated in the modulation of nervous system development, function, and disease. In this review, we detail our current understanding of the roles of the pannexin 1 (PANX1) ATP-release channel in neuronal development and plasticity, glial signaling, and neuron-glial-immune interactions. We additionally provide an overview of PANX1 structure, activation, and permeability to orientate readers and highlight recent research developments. We identify areas of convergence between PANX1 and purinergic receptor actions. Additional highlights include data on PANX1's participation in the pathophysiology of nervous system developmental, degenerative, and inflammatory disorders. Our aim in combining this knowledge is to facilitate the movement of our current understanding of PANX1 in the context of other nervous system purinergic signaling mechanisms one step closer to clinical translation.
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23
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Senthivinayagam S, Serbulea V, Upchurch CM, Polanowska-Grabowska R, Mendu SK, Sahu S, Jayaguru P, Aylor KW, Chordia MD, Steinberg L, Oberholtzer N, Uchiyama S, Inada N, Lorenz UM, Harris TE, Keller SR, Meher AK, Kadl A, Desai BN, Kundu BK, Leitinger N. Adaptive thermogenesis in brown adipose tissue involves activation of pannexin-1 channels. Mol Metab 2021; 44:101130. [PMID: 33248294 PMCID: PMC7779784 DOI: 10.1016/j.molmet.2020.101130] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 11/06/2020] [Accepted: 11/21/2020] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Brown adipose tissue (BAT) is specialized in thermogenesis. The conversion of energy into heat in brown adipocytes proceeds via stimulation of β-adrenergic receptor (βAR)-dependent signaling and activation of mitochondrial uncoupling protein 1 (UCP1). We have previously demonstrated a functional role for pannexin-1 (Panx1) channels in white adipose tissue; however, it is not known whether Panx1 channels play a role in the regulation of brown adipocyte function. Here, we tested the hypothesis that Panx1 channels are involved in brown adipocyte activation and thermogenesis. METHODS In an immortalized brown pre-adipocytes cell line, Panx1 currents were measured using patch-clamp electrophysiology. Flow cytometry was used for assessment of dye uptake and luminescence assays for adenosine triphosphate (ATP) release, and cellular temperature measurement was performed using a ratiometric fluorescence thermometer. We used RNA interference and expression plasmids to manipulate expression of wild-type and mutant Panx1. We used previously described adipocyte-specific Panx1 knockout mice (Panx1Adip-/-) and generated brown adipocyte-specific Panx1 knockout mice (Panx1BAT-/-) to study pharmacological or cold-induced thermogenesis. Glucose uptake into brown adipose tissue was quantified by positron emission tomography (PET) analysis of 18F-fluorodeoxyglucose (18F-FDG) content. BAT temperature was measured using an implantable telemetric temperature probe. RESULTS In brown adipocytes, Panx1 channel activity was induced either by apoptosis-dependent caspase activation or by β3AR stimulation via a novel mechanism that involves Gβγ subunit binding to Panx1. Inactivation of Panx1 channels in cultured brown adipocytes resulted in inhibition of β3AR-induced lipolysis, UCP-1 expression, and cellular thermogenesis. In mice, adiponectin-Cre-dependent genetic deletion of Panx1 in all adipose tissue depots resulted in defective β3AR agonist- or cold-induced thermogenesis in BAT and suppressed beigeing of white adipose tissue. UCP1-Cre-dependent Panx1 deletion specifically in brown adipocytes reduced the capacity for adaptive thermogenesis without affecting beigeing of white adipose tissue and aggravated diet-induced obesity and insulin resistance. CONCLUSIONS These data demonstrate that Gβγ-dependent Panx1 channel activation is involved in β3AR-induced thermogenic regulation in brown adipocytes. Identification of Panx1 channels in BAT as novel thermo-regulatory elements downstream of β3AR activation may have therapeutic implications.
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Affiliation(s)
| | - Vlad Serbulea
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Clint M Upchurch
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | | | - Suresh K Mendu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Srabani Sahu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Prathiba Jayaguru
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Kevin W Aylor
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Mahendra D Chordia
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Limor Steinberg
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Nathaniel Oberholtzer
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Seichii Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Noriko Inada
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka, Japan
| | - Ulrike M Lorenz
- Department of Microbiology, Immunology and Cancer Biology, Center for Cell Clearance, the Beirne B. Carter Center for Immunology Research, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Susanna R Keller
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Akshaya K Meher
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Alexandra Kadl
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Bimal N Desai
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Bijoy K Kundu
- Department of Radiology and Medical Imaging, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA; Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Norbert Leitinger
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA; Robert M Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, 22908, USA.
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Aquilino MS, Whyte-Fagundes P, Lukewich MK, Zhang L, Bardakjian BL, Zoidl GR, Carlen PL. Pannexin-1 Deficiency Decreases Epileptic Activity in Mice. Int J Mol Sci 2020; 21:ijms21207510. [PMID: 33053775 PMCID: PMC7589538 DOI: 10.3390/ijms21207510] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023] Open
Abstract
Objective: Pannexin-1 (Panx1) is suspected of having a critical role in modulating neuronal excitability and acute neurological insults. Herein, we assess the changes in behavioral and electrophysiological markers of excitability associated with Panx1 via three distinct models of epilepsy. Methods Control and Panx1 knockout C57Bl/6 mice of both sexes were monitored for their behavioral and electrographic responses to seizure-generating stimuli in three epilepsy models—(1) systemic injection of pentylenetetrazol, (2) acute electrical kindling of the hippocampus and (3) neocortical slice exposure to 4-aminopyridine. Phase-amplitude cross-frequency coupling was used to assess changes in an epileptogenic state resulting from Panx1 deletion. Results: Seizure activity was suppressed in Panx1 knockouts and by application of Panx1 channel blockers, Brilliant Blue-FCF and probenecid, across all epilepsy models. In response to pentylenetetrazol, WT mice spent a greater proportion of time experiencing severe (stage 6) seizures as compared to Panx1-deficient mice. Following electrical stimulation of the hippocampal CA3 region, Panx1 knockouts had significantly shorter evoked afterdischarges and were resistant to kindling. In response to 4-aminopyridine, neocortical field recordings in slices of Panx1 knockout mice showed reduced instances of electrographic seizure-like events. Cross-frequency coupling analysis of these field potentials highlighted a reduced coupling of excitatory delta–gamma and delta-HF rhythms in the Panx1 knockout. Significance: These results suggest that Panx1 plays a pivotal role in maintaining neuronal hyperexcitability in epilepsy models and that genetic or pharmacological targeting of Panx1 has anti-convulsant effects.
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Affiliation(s)
- Mark S. Aquilino
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
- Correspondence:
| | - Paige Whyte-Fagundes
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M5S 3G9, Canada; (P.W.-F.); (G.R.Z.)
| | - Mark K. Lukewich
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
| | - Liang Zhang
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
| | - Berj L. Bardakjian
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
| | - Georg R. Zoidl
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M5S 3G9, Canada; (P.W.-F.); (G.R.Z.)
| | - Peter L. Carlen
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
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25
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Navis KE, Fan CY, Trang T, Thompson RJ, Derksen DJ. Pannexin 1 Channels as a Therapeutic Target: Structure, Inhibition, and Outlook. ACS Chem Neurosci 2020; 11:2163-2172. [PMID: 32639715 DOI: 10.1021/acschemneuro.0c00333] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pannexin 1 (Panx1) channels are transmembrane proteins that release adenosine triphosphate and play an important role in intercellular communication. They are widely expressed in somatic and nervous system tissues, and their activity has been associated with many pathologies such as stroke, epilepsy, inflammation, and chronic pain. While there are a variety of small molecules known to inhibit Panx1, currently little is known about the mechanism of channel inhibition, and there is a dearth of sufficiently potent and selective drugs targeting Panx1. Herein we provide a review of the current literature on Panx1 structural biology and known pharmacological agents that will help provide a basis for rational development of Panx1 chemical modulators.
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Affiliation(s)
- Kathleen E. Navis
- Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Churmy Y. Fan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Tuan Trang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Roger J. Thompson
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Darren J. Derksen
- Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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26
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Giaume C, Naus CC, Sáez JC, Leybaert L. Glial Connexins and Pannexins in the Healthy and Diseased Brain. Physiol Rev 2020; 101:93-145. [PMID: 32326824 DOI: 10.1152/physrev.00043.2018] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the past several decades a large amount of data have established that glial cells, the main cell population in the brain, dynamically interact with neurons and thus impact their activity and survival. One typical feature of glia is their marked expression of several connexins, the membrane proteins forming intercellular gap junction channels and hemichannels. Pannexins, which have a tetraspan membrane topology as connexins, are also detected in glial cells. Here, we review the evidence that connexin and pannexin channels are actively involved in dynamic and metabolic neuroglial interactions in physiological as well as in pathological situations. These features of neuroglial interactions open the way to identify novel non-neuronal aspects that allow for a better understanding of behavior and information processing performed by neurons. This will also complement the "neurocentric" view by facilitating the development of glia-targeted therapeutic strategies in brain disease.
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Affiliation(s)
- Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Juan C Sáez
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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27
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Verschuren EHJ, Rigalli JP, Castenmiller C, Rohrbach MU, Bindels RJM, Peters DJM, Arjona FJ, Hoenderop JGJ. Pannexin-1 mediates fluid shear stress-sensitive purinergic signaling and cyst growth in polycystic kidney disease. FASEB J 2020; 34:6382-6398. [PMID: 32159259 DOI: 10.1096/fj.201902901r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/07/2020] [Accepted: 03/01/2020] [Indexed: 12/16/2022]
Abstract
Tubular ATP release is regulated by mechanosensation of fluid shear stress (FSS). Polycystin-1/polycystin-2 (PC1/PC2) functions as a mechanosensory complex in the kidney. Extracellular ATP is implicated in polycystic kidney disease (PKD), where PC1/PC2 is dysfunctional. This study aims to provide new insights into the ATP signaling under physiological conditions and PKD. Microfluidics, pharmacologic inhibition, and loss-of-function approaches were combined to assess the ATP release in mouse distal convoluted tubule 15 (mDCT15) cells. Kidney-specific Pkd1 knockout mice (iKsp-Pkd1-/- ) and zebrafish pkd2 morphants (pkd2-MO) were as models for PKD. FSS-exposed mDCT15 cells displayed increased ATP release. Pannexin-1 inhibition and knockout decreased FSS-modulated ATP release. In iKsp-Pkd1-/- mice, elevated renal pannexin-1 mRNA expression and urinary ATP were observed. In Pkd1-/- mDCT15 cells, elevated ATP release was observed upon the FSS mechanosensation. In these cells, increased pannexin-1 mRNA expression was observed. Importantly, pannexin-1 inhibition in pkd2-MO decreased the renal cyst growth. Our results demonstrate that pannexin-1 channels mediate ATP release into the tubular lumen due to pro-urinary flow. We present pannexin-1 as novel therapeutic target to prevent the renal cyst growth in PKD.
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Affiliation(s)
- Eric H J Verschuren
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Juan P Rigalli
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Charlotte Castenmiller
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Meike U Rohrbach
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Dorien J M Peters
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Francisco J Arjona
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
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28
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ATP amplifies NADPH-dependent and -independent neutrophil extracellular trap formation. Sci Rep 2019; 9:16556. [PMID: 31719610 PMCID: PMC6851112 DOI: 10.1038/s41598-019-53058-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/24/2019] [Indexed: 01/21/2023] Open
Abstract
Neutrophils are the first immune cells to kill invading microbes at sites of infection using a variety of processes, including the release of proteases, phagocytosis and the production of neutrophil extracellular traps (NETs). NET formation, or NETosis, is a specific and highly efficient process, which is induced by a variety of stimuli leading to expulsion of DNA, proteases and antimicrobial peptides to the extracellular space. However, uncontrolled NETosis may lead to adverse effects and exert tissue damage in pathological conditions. Here, we show that the ATP channel pannexin1 (Panx1) is functionally expressed by bone marrow-derived neutrophils (BMDNs) of wild-type (WT) mice and that ATP contributes to NETosis induced in vitro by the calcium ionophore A23187 or phorbol 12-myristate 13-acetate (PMA). Interestingly, neutrophils isolated from Panx1−/− mice showed reduced and/or delayed induction of NETosis. Brilliant blue FCF dye (BB-FCF), a Panx1 channel inhibitor, decreased NETosis in wild-type neutrophils to the extent observed in Panx1−/− neutrophils. Thus, we demonstrate that ATP and Panx1 channels contribute to NETosis and may represent a therapeutic target.
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29
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Molica F, Meens MJ, Pelli G, Hautefort A, Emre Y, Imhof BA, Fontana P, Scemes E, Morel S, Kwak BR. Selective inhibition of Panx1 channels decreases hemostasis and thrombosis in vivo. Thromb Res 2019; 183:56-62. [PMID: 31669824 DOI: 10.1016/j.thromres.2019.09.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/30/2019] [Accepted: 09/16/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Hemostasis is a tightly regulated physiological process to rapidly induce hemostatic plugs at sites of vascular injury. Inappropriate activation of this process may lead to thrombosis, i.e. pathological blood clot formation in uninjured vessels or on atherosclerotic lesions. ATP release through Pannexin1 (Panx1) membrane channels contributes to collagen-induced platelet aggregation in vitro. OBJECTIVE To investigate the effects of genetic and pharmacological inhibition of Panx1 on hemostasis and thrombosis in vivo. RESULTS Bleeding time after tail clipping was increased by 2.5-fold in Panx1-/- mice compared to wild-type controls, suggesting that Panx1 deficiency impairs primary hemostasis. Wire myography on mesenteric arteries revealed diminished vasoconstriction in response to phenylephrine or U446619 in Panx1-/- mice. Mice with platelet-specific deletion of Panx1 (Panx1PDel) displayed 2-fold longer tail bleeding times than Panx1fl/fl controls. Moreover, venous thromboembolism (VTE) after injection of collagen/epinephrine in the jugular vein was reduced in Panx1-/- and Panx1PDel mice. Panx1PDel mice also showed reduced FeCl3-induced thrombosis in mesenteric arteries. BrilliantBlue-FCF, a Panx1 channel inhibitor, decreased collagen-induced platelet aggregation in vitro, increased tail bleeding time and reduced VTE in wild-type mice. Furthermore, we developed a specific Panx1 blocking antibody targeting a Panx1 extracellular loop, which reduced ATP release from platelets in vitro. Treating wild-type mice with this antibody increased tail bleeding time and decreased VTE compared to control antibody. CONCLUSIONS Panx1 channel deletion or inhibition diminishes clot formation during hemostasis and thrombosis in vivo. Blocking Panx1 channels may be an attractive strategy for modulating platelet aggregation in thrombotic disease.
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Affiliation(s)
- Filippo Molica
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Merlijn J Meens
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Graziano Pelli
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Aurélie Hautefort
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Yalin Emre
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Beat A Imhof
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Pierre Fontana
- Division of Angiology and Haemostasis, Geneva University Hospitals and Geneva Platelet Group, University of Geneva, Geneva, Switzerland
| | - Eliana Scemes
- Dept of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
| | - Sandrine Morel
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Brenda R Kwak
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Dept of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland.
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30
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Johnsen B, Kaschubowski KE, Nader S, Schneider E, Nicola JA, Fliegert R, Wolf IMA, Guse AH, Nikolaev VO, Koch-Nolte F, Haag F. P2X7-mediated ATP secretion is accompanied by depletion of cytosolic ATP. Purinergic Signal 2019; 15:155-166. [PMID: 31016551 PMCID: PMC6635544 DOI: 10.1007/s11302-019-09654-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 03/13/2019] [Indexed: 01/23/2023] Open
Abstract
ATP and its metabolites are important extracellular signal transmitters acting on purinergic P2 and P1 receptors. Most cells can actively secrete ATP in response to a variety of external stimuli such as gating of the P2X7 receptor. We used Yac-1 murine lymphoma cells to study P2X7-mediated ATP release. These cells co-express P2X7 and ADP-ribosyltransferase ARTC2, permitting gating of P2X7 by NAD+-dependent ADP-ribosylation without the need to add exogenous ATP. Yac-1 cells released ATP into the extracellular space within minutes after stimulation with NAD+. This was blocked by pre-incubation with the inhibitory P2X7-specific nanobody 13A7. Gating of P2X7 for 3 h significantly decreased intracellular ATP levels in living cells, but these had returned to normal by 20 h. P2X7-mediated ATP release was dependent on a rise in cytosolic calcium and the depletion of intracellular potassium, but was not blocked by inhibitors of pannexins or connexins. We used genetically encoded FRET-based ATP sensors targeted to the cytosol to image P2X7-mediated changes in the distribution of ATP in 3T3 fibroblasts co-expressing P2X7 and ARTC2 and in Yac-1 cells. In response to NAD+, we observed a marked depletion of ATP in the cytosol. This study demonstrates the potential of ATP sensors as tools to study regulated ATP release by other cell types under other conditions.
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Affiliation(s)
- Bjarne Johnsen
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Klaus Eric Kaschubowski
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Sorush Nader
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Enja Schneider
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Jan-Andrei Nicola
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Ralf Fliegert
- The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Insa M A Wolf
- The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas H Guse
- The Calcium Signalling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany
| | - Friedrich Haag
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.
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31
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Kilic K, Karatas H, Dönmez-Demir B, Eren-Kocak E, Gursoy-Ozdemir Y, Can A, Petit JM, Magistretti PJ, Dalkara T. Inadequate brain glycogen or sleep increases spreading depression susceptibility. Ann Neurol 2019; 83:61-73. [PMID: 29244233 DOI: 10.1002/ana.25122] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/23/2017] [Accepted: 12/12/2017] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Glycogen in astrocyte processes contributes to maintenance of low extracellular glutamate and K+ concentrations around excitatory synapses. Sleep deprivation (SD), a common migraine trigger, induces transcriptional changes in astrocytes, reducing glycogen breakdown. We hypothesize that when glycogen utilization cannot match synaptic energy demand, extracellular K+ can rise to levels that activate neuronal pannexin-1 channels and downstream inflammatory pathway, which might be one of the mechanisms initiating migraine headaches. METHODS We suppressed glycogen breakdown by inhibiting glycogen phosphorylation with 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) and by SD. RESULTS DAB caused neuronal pannexin-1 large pore opening and activation of the downstream inflammatory pathway as shown by procaspase-1 cleavage and HMGB1 release from neurons. Six-hour SD induced pannexin-1 mRNA. DAB and SD also lowered the cortical spreading depression (CSD) induction threshold, which was reversed by glucose or lactate supplement, suggesting that glycogen-derived energy substrates are needed to prevent CSD generation. Supporting this, knocking down the neuronal lactate transporter MCT2 with an antisense oligonucleotide or inhibiting glucose transport from vessels to astrocytes with intracerebroventricularly delivered phloretin reduced the CSD threshold. In vivo recordings with a K+ -sensitive/selective fluoroprobe, Asante Potassium Green-4, revealed that DAB treatment or SD caused a significant rise in extracellular K+ during whisker stimulation, illustrating the critical role of glycogen in extracellular K+ clearance. INTERPRETATION Synaptic metabolic stress caused by insufficient glycogen-derived energy substrate supply can activate neuronal pannexin-1 channels as well as lower the CSD threshold. Therefore, conditions that limit energy supply to synapses (eg, SD) may predispose to migraine attacks, as suggested by genetic studies associating glucose or lactate transporter deficiency with migraine. Ann Neurol 2018;83:61-73.
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Affiliation(s)
- Kivilcim Kilic
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Hulya Karatas
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Buket Dönmez-Demir
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Emine Eren-Kocak
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Yasemin Gursoy-Ozdemir
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey.,Current address for Dr Gursoy-Ozdemir: Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
| | - Alp Can
- Department of Histology and Embryology, School of Medicine, Ankara University, Ankara, Turkey
| | - Jean-Marie Petit
- Center for Psychiatric Neuroscience, Department of Psychiatry, University Hospital of the Canton of Vaud (CHUV), Prilly, Switzerland
| | - Pierre J Magistretti
- King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Brain Mind Institute, Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Turgay Dalkara
- Department of Neurology, Faculty of Medicine and Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
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32
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Wang J, Jackson DG, Dahl G. Cationic control of Panx1 channel function. Am J Physiol Cell Physiol 2018; 315:C279-C289. [PMID: 29719168 DOI: 10.1152/ajpcell.00303.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The sequence and predicted membrane topology of pannexin1 (Panx1) places it in the family of gap junction proteins. However, rather than forming gap junction channels, Panx1 forms channels in the nonjunctional membrane. Panx1 operates in two distinct open states, depending on the mode of stimulation. The exclusively voltage-gated channel has a small conductance (<100 pS) and is highly selective for the flux of chloride ions. The Panx1 channel activated by various physiological stimuli or by increased concentrations of extracellular potassium ions has a large conductance (~500 pS, however, with multiple, long-lasting subconductance states) and is nonselectively permeable to small molecules, including ATP. To test whether the two open conformations also differ pharmacologically, the effects of di-and trivalent cations on the two Panx1 channel conformations were investigated. The rationale for this venture was that, under certain experimental conditions, ATP release from cells can be inhibited by multivalent cations, yet the literature indicates that the ATP release channel Panx1 is not affected by these ions. Consistent with previous reports, the Panx1 channel was not activated by removal of extracellular Ca2+ and the currents through the voltage-activated channel were not altered by Ca2+, Zn2+, Ba2+, or Gd3+. In contrast, the Panx1 channel activated to the large channel conformation by extracellular K+, osmotic stress, or low oxygen was inhibited by the multivalent cations in a dose-dependent way. Thus, monovalent cations activated the Panx1 channel from the closed state to the "large" conformation, while di- and trivalent cations exclusively inhibited this large channel conformation.
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Affiliation(s)
- Junjie Wang
- Department of Physiology and Biophysics, University of Miami School of Medicine , Miami, Florida
| | - David George Jackson
- Department of Physiology and Biophysics, University of Miami School of Medicine , Miami, Florida
| | - Gerhard Dahl
- Department of Physiology and Biophysics, University of Miami School of Medicine , Miami, Florida
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33
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Whyte-Fagundes P, Kurtenbach S, Zoidl C, Shestopalov VI, Carlen PL, Zoidl G. A Potential Compensatory Role of Panx3 in the VNO of a Panx1 Knock Out Mouse Model. Front Mol Neurosci 2018; 11:135. [PMID: 29780304 PMCID: PMC5946002 DOI: 10.3389/fnmol.2018.00135] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 04/03/2018] [Indexed: 12/30/2022] Open
Abstract
Pannexins (Panx) are integral membrane proteins, with Panx1 being the best-characterized member of the protein family. Panx1 is implicated in sensory processing, and knockout (KO) animal models have become the primary tool to investigate the role(s) of Panx1 in sensory systems. Extending previous work from our group on primary olfaction, the expression patterns of Panxs in the vomeronasal organ (VNO), an auxiliary olfactory sense organ with a role in reproduction and social behavior, were compared. Using qRT-PCR and Immunohistochemistry (IHC), we confirmed the loss of Panx1, found similar Panx2 expression levels in both models, and a significant upregulation of Panx3 in mice with a global ablation of Panx1. Specifically, Panx3 showed upregulated expression in nerve fibers of the non-sensory epithelial layer in juvenile and adult KO mice and in the sensory layer of adults, which overlaps with Panx1 expression areas in WT populations. Since both social behavior and evoked ATP release in the VNO was not compromised in KO animals, we hypothesized that Panx3 could compensate for the loss of Panx1. This led us to compare Panx1 and Panx3 channels in vitro, demonstrating similar dye uptake and ATP release properties. Outcomes of this study strongly suggest that Panx3 may functionally compensate for the loss of Panx1 in the VNO of the olfactory system, ensuring sustained chemosensory processing. This finding extends previous reports on the upregulation of Panx3 in arterial walls and the skin of Panx1 KO mice, suggesting that roles of Panx1 warrant uncharacterized safeguarding mechanisms involving Panx3.
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Affiliation(s)
- Paige Whyte-Fagundes
- Department of Biology, York University, Toronto, ON, Canada.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Stefan Kurtenbach
- Department of Biology, York University, Toronto, ON, Canada.,Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | | | - Valery I Shestopalov
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Georg Zoidl
- Department of Biology, York University, Toronto, ON, Canada.,Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Psychology, York University, Toronto, ON, Canada
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Garg C, Seo JH, Ramachandran J, Loh JM, Calderon F, Contreras JE. Trovafloxacin attenuates neuroinflammation and improves outcome after traumatic brain injury in mice. J Neuroinflammation 2018; 15:42. [PMID: 29439712 PMCID: PMC5812039 DOI: 10.1186/s12974-018-1069-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 01/17/2018] [Indexed: 12/20/2022] Open
Abstract
Background Trovafloxacin is a broad-spectrum antibiotic, recently identified as an inhibitor of pannexin-1 (Panx1) channels. Panx1 channels are important conduits for the adenosine triphosphate (ATP) release from live and dying cells that enhances the inflammatory response of immune cells. Elevated extracellular levels ATP released upon injury activate purinergic pathways in inflammatory cells that promote migration, proliferation, phagocytosis, and apoptotic signals. Here, we tested whether trovafloxacin administration attenuates the neuroinflammatory response and improves outcomes after brain trauma. Methods The murine controlled cortical impact (CCI) model was used to determine whether in vivo delivery of trovafloxacin has anti-inflammatory and neuroprotective actions after brain trauma. Locomotor deficit was assessed using the rotarod test. Levels of tissue damage markers and inflammation were measured using western blot, qPCR, and immunofluorescence. In vitro assays were used to evaluate whether trovafloxacin blocks ATP release and cell migration in a chemotactic-stimulated microglia cell line. Results Trovafloxacin treatment of CCI-injured mice significantly reduced tissue damage markers and improved locomotor deficits. In addition, trovafloxacin treatment significantly reduced mRNA levels of several pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), which correlates with an overall reduction in the accumulation of inflammatory cell types (neutrophils, microglia/macrophages, and astroglia) at the injury zone. To determine whether trovafloxacin exerted these effects by direct action on immune cells, we evaluated its effect on ATP release and cell migration using a chemotactic-stimulated microglial cell line. We found that trovafloxacin significantly inhibited both ATP release and migration of these cells. Conclusion Our results show that trovafloxacin administration has pronounced anti-inflammatory and neuroprotective effects following brain injury. These findings lay the foundation for future studies to directly test a role for Panx1 channels in pathological inflammation following brain trauma. Electronic supplementary material The online version of this article (10.1186/s12974-018-1069-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Charu Garg
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Joon Ho Seo
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Jayalakshmi Ramachandran
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Ji Meng Loh
- Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ, 07102, USA
| | - Frances Calderon
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA.
| | - Jorge E Contreras
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers University, 185 South Orange Ave, Newark, NJ, 07103, USA.
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35
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Chiu YH, Schappe MS, Desai BN, Bayliss DA. Revisiting multimodal activation and channel properties of Pannexin 1. J Gen Physiol 2017; 150:19-39. [PMID: 29233884 PMCID: PMC5749114 DOI: 10.1085/jgp.201711888] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022] Open
Abstract
Pannexin 1 (Panx1) forms plasma membrane ion channels that are widely expressed throughout the body. Panx1 activation results in the release of nucleotides such as adenosine triphosphate and uridine triphosphate. Thus, these channels have been implicated in diverse physiological and pathological functions associated with purinergic signaling, such as apoptotic cell clearance, blood pressure regulation, neuropathic pain, and excitotoxicity. In light of this, substantial attention has been directed to understanding the mechanisms that regulate Panx1 channel expression and activation. Here we review accumulated evidence for the various activation mechanisms described for Panx1 channels and, where possible, the unitary channel properties associated with those forms of activation. We also emphasize current limitations in studying Panx1 channel function and propose potential directions to clarify the exciting and expanding roles of Panx1 channels.
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Affiliation(s)
- Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Bimal N Desai
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
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36
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Luo W, Feldman D, McCallister R, Brophy C, Cheung-Flynn J. P2X7R antagonism after subfailure overstretch injury of blood vessels reverses vasomotor dysfunction and prevents apoptosis. Purinergic Signal 2017; 13:579-590. [PMID: 28905300 PMCID: PMC5714848 DOI: 10.1007/s11302-017-9585-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 08/25/2017] [Indexed: 12/13/2022] Open
Abstract
Human saphenous vein (HSV) is harvested and prepared prior to implantation as an arterial bypass graft. Injury and the response to injury from surgical harvest and preparation trigger cascades of molecular events and contribute to graft remodeling and intimal hyperplasia. Apoptosis is an early response after implantation that contributes the development of neointimal lesions. Here, we showed that surgical harvest and preparation of HSV leads to vasomotor dysfunction, increased apoptosis and downregulation of the phosphorylation of the anti-apoptotic protein, Niban. A model of subfailure overstretch injury in rat aorta (RA) was used to demonstrate impaired vasomotor function, increased extracellular ATP (eATP) release, and increased apoptosis following pathological vascular injury. The subfailure overstretch injury was associated with activation of p38 MAPK stress pathway and decreases in the phosphorylation of the anti-apoptotic protein Niban. Treatment of RA after overstretch injury with antagonists to purinergic P2X7 receptor (P2X7R) antagonists or P2X7R/pannexin (PanX1) complex, but not PanX1 alone, restored vasomotor function. Inhibitors to P2X7R and PanX1 reduced stretch-induced eATP release. P2X7R/PanX1 antagonism led to decrease in p38 MAPK phosphorylation, restoration of Niban phosphorylation and increases in the phosphorylation of the anti-apoptotic protein Akt in RA and reduced TNFα-stimulated caspase 3/7 activity in cultured rat vascular smooth muscle cells. In conclusion, inhibition of P2X7R after overstretch injury restored vasomotor function and inhibited apoptosis. Treatment with P2X7R/PanX1 complex inhibitors after harvest and preparation injury of blood vessels used for bypass conduits may prevent the subsequent response to injury that lead to apoptosis and represents a novel therapeutic approach to prevent graft failure.
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Affiliation(s)
- Weifeng Luo
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Daniel Feldman
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Reid McCallister
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Colleen Brophy
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
- VA Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Joyce Cheung-Flynn
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
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37
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Willebrords J, Maes M, Crespo Yanguas S, Vinken M. Inhibitors of connexin and pannexin channels as potential therapeutics. Pharmacol Ther 2017; 180:144-160. [PMID: 28720428 PMCID: PMC5802387 DOI: 10.1016/j.pharmthera.2017.07.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
While gap junctions support the exchange of a number of molecules between neighboring cells, connexin hemichannels provide communication between the cytosol and the extracellular environment of an individual cell. The latter equally holds true for channels composed of pannexin proteins, which display an architecture reminiscent of connexin hemichannels. In physiological conditions, gap junctions are usually open, while connexin hemichannels and, to a lesser extent, pannexin channels are typically closed, yet they can be activated by a number of pathological triggers. Several agents are available to inhibit channels built up by connexin and pannexin proteins, including alcoholic substances, glycyrrhetinic acid, anesthetics and fatty acids. These compounds not always strictly distinguish between gap junctions, connexin hemichannels and pannexin channels, and may have effects on other targets as well. An exception lies with mimetic peptides, which reproduce specific amino acid sequences in connexin or pannexin primary protein structure. In this paper, a state-of-the-art overview is provided on inhibitors of cellular channels consisting of connexins and pannexins with specific focus on their mode-of-action and therapeutic potential.
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Affiliation(s)
- Joost Willebrords
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Michaël Maes
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Sara Crespo Yanguas
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium.
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38
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Chen SP, Qin T, Seidel JL, Zheng Y, Eikermann M, Ferrari MD, van den Maagdenberg AMJM, Moskowitz MA, Ayata C, Eikermann-Haerter K. Inhibition of the P2X7-PANX1 complex suppresses spreading depolarization and neuroinflammation. Brain 2017; 140:1643-1656. [PMID: 28430869 DOI: 10.1093/brain/awx085] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 02/12/2017] [Indexed: 01/09/2023] Open
Abstract
Spreading depolarization is a wave of neuronal and glial depolarization. Within minutes after spreading depolarization, the neuronal hemichannel pannexin 1 (PANX1) opens and forms a pore complex with the ligand-gated cation channel P2X7, allowing the release of excitatory neurotransmitters to sustain spreading depolarization and activate neuroinflammation. Here, we explore the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility with important consequences for neuroinflammation and trigeminovascular activation. We found that genetic loss of function or ablation of the P2x7 gene inhibits spreading depolarization. Moreover, pharmacological suppression of the P2X7-PANX1 pore complex inhibits spreading depolarization in mice carrying the human familial hemiplegic migraine type 1 R192Q missense mutation as well as in wild-type mice and rats. Pore inhibitors elevate the electrical threshold for spreading depolarization, and reduce spreading depolarization frequency and amplitude. Pore inhibitors also suppress downstream consequences of spreading depolarization such as upregulation of interleukin-1 beta, inducible nitric oxide synthase and cyclooxygenase-2 in the cortex after spreading depolarization. In addition, they inhibit surrogates for trigeminovascular activation, including expression of calcitonin gene-related peptide in the trigeminal ganglion and c-Fos in the trigeminal nucleus caudalis. Our results are consistent with the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility and its downstream consequences, of potential relevance to its signature disorders such as migraine.
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Affiliation(s)
- Shih-Pin Chen
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Tao Qin
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jessica L Seidel
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Yi Zheng
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Matthias Eikermann
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA and Universitaet Duisburg Essen, Essen, Germany
| | - Michel D Ferrari
- Department of Neurology, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
| | - Arn M J M van den Maagdenberg
- Department of Neurology, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands.,Department of Human Genetics, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
| | - Michael A Moskowitz
- Stroke and Neurovascular Regulation Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Cenk Ayata
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Katharina Eikermann-Haerter
- Neurovascular Research Lab, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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39
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Ribeiro T, Oliveira JT, Almeida FM, Tomaz MA, Melo PA, Marques SA, de Andrade GM, Martinez AMB. Blockade of ATP P2X7 receptor enhances ischiatic nerve regeneration in mice following a crush injury. Brain Res 2017; 1669:69-78. [PMID: 28554806 DOI: 10.1016/j.brainres.2017.05.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 05/15/2017] [Accepted: 05/22/2017] [Indexed: 12/31/2022]
Abstract
Preventing damage caused by nerve degeneration is a great challenge. There is a growing body of evidence implicating extracellular nucleotides and their P2 receptors in many pathophysiological mechanisms. In this work we aimed to investigate the effects of the administration of Brilliant Blue G (BBG) and Pyridoxalphosphate-6-azophenyl-2', 4'- disulphonic acid (PPADS), P2X7 and P2 non-selective receptor antagonists, respectively, on sciatic nerve regeneration. Four groups of mice that underwent nerve crush lesion were used: two control groups treated with vehicle (saline), a group treated with BBG and a group treated with PPADS during 28days. Gastrocnemius muscle weight was evaluated. For functional evaluation we used the Sciatic Functional Index (SFI) and the horizontal ladder walking test. Nerves, dorsal root ganglia and spinal cords were processed for light and electron microscopy. Antinoceptive effects of BBG and PPADS were evaluated through von Frey E, and the levels of IL-1β and TNF-α were analyzed by ELISA. BBG promoted an increase in the number of myelinated fibers and on axon, fiber and myelin areas. BBG and PPADS led to an increase of TNF-α and IL-1β in the nerve on day 1 and PPADS caused a decrease of IL-1β on day 7. Mechanical allodynia was reversed on day 7 in the groups treated with BBG and PPADS. We concluded that BBG promoted a better morphological regeneration after ischiatic crush injury, but this was not followed by anticipation of functional improvement. In addition, both PPADS and BBG presented anti-inflammatory as well as antinociceptive effects.
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Affiliation(s)
- Tatianne Ribeiro
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, HUCFF, UFRJ, Rio de Janeiro, RJ, Brazil
| | - Júlia Teixeira Oliveira
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, HUCFF, UFRJ, Rio de Janeiro, RJ, Brazil
| | - Fernanda Martins Almeida
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, HUCFF, UFRJ, Rio de Janeiro, RJ, Brazil
| | - Marcelo Amorim Tomaz
- Laboratório de Farmacologia das Toxinas, Programa de Pós-Graduação em Farmacologia e Química Medicinal, ICB, CCS, UFRJ, Brazil
| | - Paulo A Melo
- Laboratório de Farmacologia das Toxinas, Programa de Pós-Graduação em Farmacologia e Química Medicinal, ICB, CCS, UFRJ, Brazil
| | - Suelen Adriani Marques
- Laboratório de Regeneração Neural e Função, Departamento de Neurobiologia, Instituto de Biologia, UFF, Rio de Janeiro, Brazil
| | - Geanne Matos de Andrade
- Laboratório de Neurociências e Comportamento, Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, UFC, Ceará, Brazil.
| | - Ana Maria Blanco Martinez
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, HUCFF, UFRJ, Rio de Janeiro, RJ, Brazil.
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40
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Molica F, Stierlin FB, Fontana P, Kwak BR. Pannexin- and Connexin-Mediated Intercellular Communication in Platelet Function. Int J Mol Sci 2017; 18:E850. [PMID: 28420171 PMCID: PMC5412434 DOI: 10.3390/ijms18040850] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/06/2017] [Accepted: 04/12/2017] [Indexed: 12/11/2022] Open
Abstract
The three major blood cell types, i.e., platelets, erythrocytes and leukocytes, are all produced in the bone marrow. While red blood cells are the most numerous and white cells are the largest, platelets are small fragments and account for a minor part of blood volume. However, platelets display a crucial function by preventing bleeding. Upon vessel wall injury, platelets adhere to exposed extracellular matrix, become activated, and form a platelet plug preventing hemorrhagic events. However, when platelet activation is exacerbated, as in rupture of an atherosclerotic plaque, the same mechanism may lead to acute thrombosis causing major ischemic events such as myocardial infarction or stroke. In the past few years, major progress has been made in understanding of platelet function modulation. In this respect, membrane channels formed by connexins and/or pannexins are of particular interest. While it is still not completely understood whether connexins function as hemichannels or gap junction channels to inhibit platelet aggregation, there is clear-cut evidence for a specific implication of pannexin1 channels in collagen-induced aggregation. The focus of this review is to summarize current knowledge of the role of connexins and pannexins in platelet aggregation and to discuss possible pharmacological approaches along with their limitations and future perspectives for new potential therapies.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
| | - Florian B Stierlin
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
- Geneva Platelet Group, University of Geneva, 1211 Geneva, Switzerland.
| | - Pierre Fontana
- Geneva Platelet Group, University of Geneva, 1211 Geneva, Switzerland.
- Division of Angiology and Haemostasis, Geneva University Hospitals, 1211 Geneva, Switzerland.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
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41
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Molica F, Nolli S, Fontana P, Kwak BR. Turbidimetry on Human Washed Platelets: The Effect of the Pannexin1-inhibitor Brilliant Blue FCF on Collagen-induced Aggregation. J Vis Exp 2017. [PMID: 28448011 DOI: 10.3791/55525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Turbidimetry is a laboratory technique that is applied to measure the aggregation of platelets suspended in either plasma (platelet-rich plasma, PRP) or in buffer (washed platelets), by the use of one or a combination of agonists. The use of washed platelets separated from their plasma environment and in the absence of anticoagulants allows for studying intrinsic platelet properties. Among the large panel of agonists, arachidonic acid (AA), adenosine di-phosphate (ADP), thrombin and collagen are the most frequently used. The aggregation response is quantified by measuring the relative optical density (OD) over time of platelet suspension under continuous stirring. Platelets in homogeneous suspension limit the passage of light after the addition of an agonist, platelet shape change occurs producing a small transitory increase in OD. Following this initial activation step, platelet clots form gradually, allowing the passage of light through the suspension as a result of decreased OD. The aggregation process is ultimately expressed as a percentage, compared to the OD of platelet-poor plasma or buffer. Rigorous calibration is thus essential at the beginning of each experiment. As a general rule: calibration to 0% is set by measuring the OD of a non-stimulated platelet suspension while measuring the OD of the suspension medium containing no platelets represents a value of 100%. Platelet aggregation is generally visualized as a real-time aggregation curve. Turbidimetry is one of the most commonly used laboratory techniques for the investigation of platelet function and is considered as the historical gold standard and used for the development of new pharmaceutical agents aimed at inhibiting platelet aggregation. Here, we describe detailed protocols for 1) preparation of human washed platelets and 2) turbidimetric analysis of collagen-induced aggregation of human washed platelets pretreated with the food dye Brilliant Blue FCF that was recently identified as an inhibitor of Pannexin1 (Panx1) channels.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva;
| | - Séverine Nolli
- Division of Angiology and Haemostasis & Geneva Platelet Group, Geneva University Hospitals
| | - Pierre Fontana
- Division of Angiology and Haemostasis & Geneva Platelet Group, Geneva University Hospitals
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42
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Scemes E, Velíšková J. Exciting and not so exciting roles of pannexins. Neurosci Lett 2017; 695:25-31. [PMID: 28284836 DOI: 10.1016/j.neulet.2017.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/02/2017] [Accepted: 03/06/2017] [Indexed: 01/24/2023]
Abstract
It is the current view that purinergic signaling regulates many physiological functions. Pannexin1 (Panx1), a member of the gap junction family of proteins is an ATP releasing channel that plays important physio-pathological roles in various tissues, including the CNS. Upon binding to purinergic receptors expressed in neural cells, ATP triggers cellular responses including increased cell proliferation, cell morphology changes, release of cytokines, and regulation of neuronal excitability via release of glutamate, GABA and ATP itself. Under pathological conditions such as ischemia, trauma, inflammation, and epilepsy, extracellular ATP concentrations increases drastically but the consequences of this surge is still difficult to characterize due to its rapid metabolism in ADP and adenosine, the latter having inhibitory action on neuronal activity. For seizures, for instance, the excitatory effect of ATP on neuronal activity is mainly related to its action of P2X receptors, while the inhibitory effects are related to activation of P1, adenosine receptors. Here we provide a mini review on the properties of pannexins with a main focus on Panx1 and its involvement in seizure activity. Although there are only few studies implicating Panx1 in seizures, they are illustrative of the dual role that Panx1 has on neuronal excitability.
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Affiliation(s)
- Eliana Scemes
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Jana Velíšková
- Departments of Cell Biology & Anatomy, Obstetrics & Gynecology and Neurology, New York Medical College, Valhalla, NY, 10595, USA.
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43
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Baaske R, Richter M, Möller N, Ziesemer S, Eiffler I, Müller C, Hildebrandt JP. ATP Release from Human Airway Epithelial Cells Exposed to Staphylococcus aureus Alpha-Toxin. Toxins (Basel) 2016; 8:toxins8120365. [PMID: 27929417 PMCID: PMC5198559 DOI: 10.3390/toxins8120365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 11/20/2022] Open
Abstract
Airway epithelial cells reduce cytosolic ATP content in response to treatment with S. aureus alpha-toxin (hemolysin A, Hla). This study was undertaken to investigate whether this is due to attenuated ATP generation or to release of ATP from the cytosol and extracellular ATP degradation by ecto-enzymes. Exposure of cells to rHla did result in mitochondrial calcium uptake and a moderate decline in mitochondrial membrane potential, indicating that ATP regeneration may have been attenuated. In addition, ATP may have left the cells through transmembrane pores formed by the toxin or through endogenous release channels (e.g., pannexins) activated by cellular stress imposed on the cells by toxin exposure. Exposure of cells to an alpha-toxin mutant (H35L), which attaches to the host cell membrane but does not form transmembrane pores, did not induce ATP release from the cells. The Hla-mediated ATP-release was completely blocked by IB201, a cyclodextrin-inhibitor of the alpha-toxin pore, but was not at all affected by inhibitors of pannexin channels. These results indicate that, while exposure of cells to rHla may somewhat reduce ATP production and cellular ATP content, a portion of the remaining ATP is released to the extracellular space and degraded by ecto-enzymes. The release of ATP from the cells may occur directly through the transmembrane pores formed by alpha-toxin.
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Affiliation(s)
- Romina Baaske
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Mandy Richter
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Nils Möller
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Sabine Ziesemer
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Ina Eiffler
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Christian Müller
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
| | - Jan-Peter Hildebrandt
- Animal Physiology and Biochemistry, Ernst Moritz Arndt-University, Felix Hausdorff-Strasse 1, B.10.06, D-17489 Greifswald, Germany.
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Brilliant Blue Dyes in Daily Food: How Could Purinergic System Be Affected? INTERNATIONAL JOURNAL OF FOOD SCIENCE 2016; 2016:7548498. [PMID: 27833914 PMCID: PMC5090090 DOI: 10.1155/2016/7548498] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/28/2016] [Indexed: 11/21/2022]
Abstract
Dyes were first obtained from the extraction of plant sources in the Neolithic period to produce dyed clothes. At the beginning of the 19th century, synthetic dyes were produced to color clothes on a large scale. Other applications for synthetic dyes include the pharmaceutical and food industries, which are important interference factors in our lives and health. Herein, we analyzed the possible implications of some dyes that are already described as antagonists of purinergic receptors, including special Brilliant Blue G and its derivative FD&C Blue No. 1. Purinergic receptor family is widely expressed in the body and is critical to relate to much cellular homeostasis maintenance as well as inflammation and cell death. In this review, we discuss previous studies and show purinergic signaling as an important issue to be aware of in food additives development and their correlations with the physiological functions.
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Dahl G. ATP release through pannexon channels. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0191. [PMID: 26009770 DOI: 10.1098/rstb.2014.0191] [Citation(s) in RCA: 170] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Extracellular adenosine triphosphate (ATP) serves as a signal for diverse physiological functions, including spread of calcium waves between astrocytes, control of vascular oxygen supply and control of ciliary beat in the airways. ATP can be released from cells by various mechanisms. This review focuses on channel-mediated ATP release and its main enabler, Pannexin1 (Panx1). Six subunits of Panx1 form a plasma membrane channel termed 'pannexon'. Depending on the mode of stimulation, the pannexon has large conductance (500 pS) and unselective permeability to molecules less than 1.5 kD or is a small (50 pS), chloride-selective channel. Most physiological and pathological stimuli induce the large channel conformation, whereas the small conformation so far has only been observed with exclusive voltage activation of the channel. The interaction between pannexons and ATP is intimate. The pannexon is not only the conduit for ATP, permitting ATP efflux from cells down its concentration gradient, but the pannexon is also modulated by ATP. The channel can be activated by ATP through both ionotropic P2X as well as metabotropic P2Y purinergic receptors. In the absence of a control mechanism, this positive feedback loop would lead to cell death owing to the linkage of purinergic receptors with apoptotic processes. A control mechanism preventing excessive activation of the purinergic receptors is provided by ATP binding (with low affinity) to the Panx1 protein and gating the channel shut.
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Affiliation(s)
- Gerhard Dahl
- School of Medicine, University of Miami, 1600 NW 10th Avenue, Miami, FL 33136, USA
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P2X7R large pore is partially blocked by pore forming proteins antagonists in astrocytes. J Bioenerg Biomembr 2016; 48:309-24. [DOI: 10.1007/s10863-016-9649-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/20/2016] [Indexed: 01/13/2023]
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Michalski K, Kawate T. Carbenoxolone inhibits Pannexin1 channels through interactions in the first extracellular loop. ACTA ACUST UNITED AC 2016; 147:165-74. [PMID: 26755773 PMCID: PMC4727946 DOI: 10.1085/jgp.201511505] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022]
Abstract
A chimeric approach combined with extensive site-directed mutagenesis reveals new information about the interaction of the toxin carbenoxolone with the ATP release channel Pannexin1 and the role of the first extracellular loop in channel gating. Pannexin1 (Panx1) is an ATP release channel important for controlling immune responses and synaptic strength. Various stimuli including C-terminal cleavage, a high concentration of extracellular potassium, and voltage have been demonstrated to activate Panx1. However, it remains unclear how Panx1 senses and integrates such diverse stimuli to form an open channel. To provide a clue on the mechanism underlying Panx1 channel gating, we investigated the action mechanism of carbenoxolone (CBX), the most commonly used small molecule for attenuating Panx1 function triggered by a wide range of stimuli. Using a chimeric approach, we discovered that CBX reverses its action polarity and potentiates the voltage-gated channel activity of Panx1 when W74 in the first extracellular loop is mutated to a nonaromatic residue. A systematic mutagenesis study revealed that conserved residues in this loop also play important roles in CBX function, potentially by mediating CBX binding. We extended our experiments to other Panx1 inhibitors such as probenecid and ATP, which also potentiate the voltage-gated channel activity of a Panx1 mutant at position 74. Notably, probenecid alone can activate this mutant at a resting membrane potential. These data suggest that CBX and other inhibitors, including probenecid, attenuate Panx1 channel activity through modulation of the first extracellular loop. Our experiments are the first step toward identifying a previously unknown mode of CBX action, which provide insight into the role of the first extracellular loop in Panx1 channel gating.
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Affiliation(s)
- Kevin Michalski
- Department of Molecular Medicine, Field of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY 14853
| | - Toshimitsu Kawate
- Department of Molecular Medicine, Field of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY 14853
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Feng L, Chen Y, Ding R, Fu Z, Yang S, Deng X, Zeng J. P2X7R blockade prevents NLRP3 inflammasome activation and brain injury in a rat model of intracerebral hemorrhage: involvement of peroxynitrite. J Neuroinflammation 2015; 12:190. [PMID: 26475134 PMCID: PMC4609067 DOI: 10.1186/s12974-015-0409-2] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/05/2015] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The NLR family, pyrin domain-containing 3 (NLRP3) inflammasome plays a key role in intracerebral hemorrhage (ICH)-induced inflammatory injury, and the purinergic 2X7 receptor (P2X7R) is upstream of NLRP3 activation. This study aimed to investigate how P2X7R functions in ICH-induced inflammatory injury and how the receptor interacts with the NLRP3 inflammasome. METHODS Rats were treated with P2X7R small interfering RNA (siRNA) 24 h before undergoing collagenase-induced ICH. A selective P2X7R inhibitor (blue brilliant G, BBG) or a peroxynitrite (ONOO(-)) decomposition catalyst (5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron(III) [FeTPPS]) was injected 30 min after ICH. Brain water content, hemorrhagic lesion volume, and neurological deficits were evaluated, and western blot, immunofluorescence, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) were carried out. RESULTS Striatal P2X7R and NLRP3 inflammasomes were activated after ICH. Gene silencing of P2X7R suppressed NLRP3 inflammasome activation and interleukin (IL)-1β/IL-18 release and significantly ameliorated brain edema and neurological deficits. Additionally, enhanced NADPH oxidase 2 (NOX2, gp91(phox)) and inducible nitric oxide synthase (iNOS), as well as their cytotoxic product (ONOO(-)) were markedly attenuated by BBG treatment following ICH. This was accompanied by downregulations of the inflammasome components, IL-1β/IL-18 and myeloperoxidase (MPO, a neutrophil marker). Most importantly, inflammasome activation and IL-1β/IL-18 release were significantly inhibited by ONOO(-) decomposition with FeTPPS. CONCLUSIONS Our findings implicate that P2X7R exacerbated inflammatory progression and brain damage in ICH rats possibly via NLRP3 inflammasome-dependent IL-1β/IL-18 release and neutrophil infiltration. ONOO(-), a potential downstream signaling molecule of P2X7R, may play a critical role in triggering NLRP3 inflammasome activation.
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Affiliation(s)
- Liang Feng
- The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, 510282, China.
| | - Yizhao Chen
- The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, 510282, China.
| | - Rui Ding
- Department of Neurosurgery, Jingmen No. 1 People's Hospital, Jingmen, 448000, Hubei, China.
| | - Zhenghao Fu
- Department of Neurosurgery, The Fifth Affiliated Hospital of Southern Medical University, Guangzhou, 510900, China.
| | - Shuo Yang
- Department of Neurosurgery, Gaoqing Campus of Central Hospital of Zibo, Gaoqing People's Hospital, Gaoqing, Zibo, 256300, Shandong, China.
| | - Xinqing Deng
- Department of Neurosurgery, 999 Brain Hospital, Jinan University, Guangzhou, 510510, Guangdong, China.
| | - Jun Zeng
- The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, 510282, China.
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Pannexin 1 is required for full activation of insulin-stimulated glucose uptake in adipocytes. Mol Metab 2015; 4:610-8. [PMID: 26413467 PMCID: PMC4563021 DOI: 10.1016/j.molmet.2015.06.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 06/27/2015] [Indexed: 02/08/2023] Open
Abstract
Objective Defective glucose uptake in adipocytes leads to impaired metabolic homeostasis and insulin resistance, hallmarks of type 2 diabetes. Extracellular ATP-derived nucleotides and nucleosides are important regulators of adipocyte function, but the pathway for controlled ATP release from adipocytes is unknown. Here, we investigated whether Pannexin 1 (Panx1) channels control ATP release from adipocytes and contribute to metabolic homeostasis. Methods We assessed Panx1 functionality in cultured 3T3-L1 adipocytes and in adipocytes isolated from murine white adipose tissue by measuring ATP release in response to known activators of Panx1 channels. Glucose uptake in cultured 3T3-L1 adipocytes was measured in the presence of Panx1 pharmacologic inhibitors and in adipocytes isolated from white adipose tissue from wildtype (WT) or adipocyte-specific Panx1 knockout (AdipPanx1 KO) mice generated in our laboratory. We performed in vivo glucose uptake studies in chow fed WT and AdipPanx1 KO mice and assessed insulin resistance in WT and AdipPanx1 KO mice fed a high fat diet for 12 weeks. Panx1 channel function was assessed in response to insulin by performing electrophysiologic recordings in a heterologous expression system. Finally, we measured Panx1 mRNA in human visceral adipose tissue samples by qRT-PCR and compared expression levels with glucose levels and HOMA-IR measurements in patients. Results Our data show that adipocytes express functional Pannexin 1 (Panx1) channels that can be activated to release ATP. Pharmacologic inhibition or selective genetic deletion of Panx1 from adipocytes decreased insulin-induced glucose uptake in vitro and in vivo and exacerbated diet-induced insulin resistance in mice. Further, we identify insulin as a novel activator of Panx1 channels. In obese humans Panx1 expression in adipose tissue is increased and correlates with the degree of insulin resistance. Conclusions We show that Panx1 channel activity regulates insulin-stimulated glucose uptake in adipocytes and thus contributes to control of metabolic homeostasis. Adipocytes express Pannexin 1 channels that can be activated to release ATP. Inhibition of Pannexin 1 decreased insulin-induced glucose uptake in adipocytes. Adipocyte Pannexin 1 knockout mice are more insulin resistant on high fat diet. We identify insulin as a novel activator of Pannexin 1 channels. Pannexin 1 expression in human adipose tissue correlates with insulin resistance.
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Di Cesare Mannelli L, Marcoli M, Micheli L, Zanardelli M, Maura G, Ghelardini C, Cervetto C. Oxaliplatin evokes P2X7-dependent glutamate release in the cerebral cortex: A pain mechanism mediated by Pannexin 1. Neuropharmacology 2015; 97:133-41. [PMID: 26071109 DOI: 10.1016/j.neuropharm.2015.05.037] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/11/2015] [Accepted: 05/27/2015] [Indexed: 01/29/2023]
Abstract
Anticancer therapy based on the repeated administration of oxaliplatin is limited by the development of a neuropathic syndrome difficult to treat. Oxaliplatin neurotoxicity is based on complex nervous mechanisms, the comprehension of the role of single neurotransmitters and the knowledge of the signal flow among cells is matter of importance to improve therapeutic chances. In a rat model of oxaliplatin-induced neuropathy, we report increased P2X7-evoked glutamate release from cerebrocortical synaptosomes. The release was abolished by the P2X7 receptor (P2X7R) antagonists Brilliant-Blue-G (BBG) and A-438079, and significantly reduced by Carbenoxolone and the Pannexin 1 (Panx1) selective inhibitors Erioglaucine and (10)Panx suggesting the recruitment of Panx1. Aimed to evaluate the significance of P2X7R-Panx1 system activation in pain generated by oxaliplatin, pharmacological modulators were spinally infused by intrathecal catheter in oxaliplatin-treated animals. BBG, Erioglaucine and (10)Panx reverted oxaliplatin-dependent pain. Finally, the influence of the P2X7R-Panx1 system blockade on oxaliplatin anticancer activity was evaluated on the human colon cancer cell line HT-29. Prevention of HT-29 apoptosis and mortality was dependent by kind and concentration of P2X7R antagonists. On the contrary, the inhibition of Panx1 did not alter oxaliplatin lethality in tumor cells. It is concluded that glutamate release dependent on P2X7R is increased in cerebrocortical nerve terminals from oxaliplatin-treated rats; the increase is mediated by functional recruitment of Panx1; P2X7R antagonists and Panx1 inhibitors revert oxaliplatin-induced neuropathic pain; Panx1 inhibitors do not alter the oxaliplatin-induced mortality of cancer cells HT-29. The inhibition of Panx1 channel is suggested as a new and safe pharmacological target.
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Affiliation(s)
- Lorenzo Di Cesare Mannelli
- Department of Neuroscience, Psychology, Drug Research and Child Health - Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy.
| | - Manuela Marcoli
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genova, Genova, Italy.
| | - Laura Micheli
- Department of Neuroscience, Psychology, Drug Research and Child Health - Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Matteo Zanardelli
- Department of Neuroscience, Psychology, Drug Research and Child Health - Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Guido Maura
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genova, Genova, Italy
| | - Carla Ghelardini
- Department of Neuroscience, Psychology, Drug Research and Child Health - Neurofarba, Pharmacology and Toxicology Section, University of Florence, Florence, Italy
| | - Chiara Cervetto
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genova, Genova, Italy
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