1
|
Alvarez Y, Mancebo C, Alonso S, Montero O, Fernández N, Sánchez Crespo M. Central carbon metabolism exhibits unique characteristics during the handling of fungal patterns by monocyte-derived dendritic cells. Redox Biol 2024; 73:103187. [PMID: 38744190 PMCID: PMC11103932 DOI: 10.1016/j.redox.2024.103187] [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: 03/05/2024] [Revised: 04/26/2024] [Accepted: 05/08/2024] [Indexed: 05/16/2024] Open
Abstract
Monocyte-derived dendritic cells (MDDCs) are key players in the defense against fungal infection because of their outstanding capacity for non-opsonic phagocytosis and phenotypic plasticity. Accordingly, MDDCs rewire metabolism to meet the energetic demands for microbial killing and biomass synthesis required to restore homeostasis. It has been commonplace considering the metabolic reprogramming a mimicry of the Warburg effect observed in tumor cells. However, this may be an oversimplification since the offshoots of glycolysis and the tricarboxylic acid (TCA) cycle are connected in central carbon metabolism. Zymosan, the external wall of Saccharomyces cerevisiae, contains β-glucan and α-mannan chains that engage the C-type lectin receptors dectin-1/2 and Toll-like receptors. This makes it an optimal fungal surrogate for experimental research. Using real-time bioenergetic assays and [U-13C]glucose labeling, central hubs connected to cytokine expression were identified. The pentose phosphate pathway (PPP) exhibited a more relevant capacity to yield ribose-5-phosphate than reducing equivalents of NADPH, as judged from the high levels of isotopologues showing 13C-labeling in the ribose moiety and the limited contribution of the oxidative arm of the PPP to the production of ROS by NADPH oxidases (NOX). The finding of 13C-label in the purine ring and in glutathione unveiled the contribution of serine-derived glycine to purine ring and glutathione synthesis. Serine synthesis also supported the TCA cycle. Zymosan exhausted NAD+ and ATP, consistent with intracellular consumption and/or extracellular export. Poly-ADP-ribosylated proteins detected in the nuclear fractions of MDDCs did not show major changes upon zymosan stimulation, which suggests its dependence on constitutive Fe(II)/2-oxoglutarate-dependent demethylation of 5-methylcytosine by TET translocases and/or demethylation of histone H3 lysine 27 by JMJD demethylases rather than on NOX activities. These results disclose a unique pattern of central carbon metabolism following fungal challenge, characterized by the leverage of glycolysis offshoots and an extensive recycling of NAD+ and poly(ADP-ribose).
Collapse
Affiliation(s)
- Yolanda Alvarez
- Departamento de Bioquímica, Biología Molecular y Fisiología, Universidad de Valladolid, 47003, Valladolid, Spain
| | - Cristina Mancebo
- Departamento de Bioquímica, Biología Molecular y Fisiología, Universidad de Valladolid, 47003, Valladolid, Spain
| | - Sara Alonso
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular, CSIC-Universidad de Valladolid, 47003, Valladolid, Spain
| | - Olimpio Montero
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular, CSIC-Universidad de Valladolid, 47003, Valladolid, Spain
| | - Nieves Fernández
- Departamento de Bioquímica, Biología Molecular y Fisiología, Universidad de Valladolid, 47003, Valladolid, Spain; Unidad de Excelencia Instituto de Biomedicina y Genética Molecular, CSIC-Universidad de Valladolid, 47003, Valladolid, Spain
| | - Mariano Sánchez Crespo
- Unidad de Excelencia Instituto de Biomedicina y Genética Molecular, CSIC-Universidad de Valladolid, 47003, Valladolid, Spain.
| |
Collapse
|
2
|
Lucaciu SA, Leighton SE, Hauser A, Yee R, Laird DW. Diversity in connexin biology. J Biol Chem 2023; 299:105263. [PMID: 37734551 PMCID: PMC10598745 DOI: 10.1016/j.jbc.2023.105263] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/08/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023] Open
Abstract
Over 35 years ago the cell biology community was introduced to connexins as the subunit employed to assemble semicrystalline clusters of intercellular channels that had been well described morphologically as gap junctions. The decade that followed would see knowledge of the unexpectedly large 21-member human connexin family grow to reflect unique and overlapping expression patterns in all organ systems. While connexin biology initially focused on their role in constructing highly regulated intercellular channels, this was destined to change as discoveries revealed that connexin hemichannels at the cell surface had novel roles in many cell types, especially when considering connexin pathologies. Acceptance of connexins as having bifunctional channel properties was initially met with some resistance, which has given way in recent years to the premise that connexins have multifunctional properties. Depending on the connexin isoform and cell of origin, connexins have wide-ranging half-lives that vary from a couple of hours to the life expectancy of the cell. Diversity in connexin channel characteristics and molecular properties were further revealed by X-ray crystallography and single-particle cryo-EM. New avenues have seen connexins or connexin fragments playing roles in cell adhesion, tunneling nanotubes, extracellular vesicles, mitochondrial membranes, transcription regulation, and in other emerging cellular functions. These discoveries were largely linked to Cx43, which is prominent in most human organs. Here, we will review the evolution of knowledge on connexin expression in human adults and more recent evidence linking connexins to a highly diverse array of cellular functions.
Collapse
Affiliation(s)
- Sergiu A Lucaciu
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Stephanie E Leighton
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
| | - Alexandra Hauser
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
| | - Ryan Yee
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
| |
Collapse
|
3
|
Meng JH, Chen CX, Ahmadian MR, Zan H, Luo KJ, Jiang JX. Cross-Activation of Hemichannels/Gap Junctions and Immunoglobulin-Like Domains in Innate–Adaptive Immune Responses. Front Immunol 2022; 13:882706. [PMID: 35911693 PMCID: PMC9334851 DOI: 10.3389/fimmu.2022.882706] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
Hemichannels (HCs)/gap junctions (GJs) and immunoglobulin (Ig)-like domain-containing proteins (IGLDCPs) are involved in the innate–adaptive immune response independently. Despite of available evidence demonstrating the importance of HCs/GJs and IGLDCPs in initiating, implementing, and terminating the entire immune response, our understanding of their mutual interactions in immunological function remains rudimentary. IGLDCPs include immune checkpoint molecules of the immunoglobulin family expressed in T and B lymphocytes, most of which are cluster of differentiation (CD) antigens. They also constitute the principal components of the immunological synapse (IS), which is formed on the cell surface, including the phagocytic synapse, T cell synapse, B cell synapse, and astrocytes–neuronal synapse. During the three stages of the immune response, namely innate immunity, innate–adaptive immunity, and adaptive immunity, HCs/GJs and IGLDCPs are cross-activated during the entire process. The present review summarizes the current understanding of HC-released immune signaling factors that influence IGLDCPs in regulating innate–adaptive immunity. ATP-induced “eat me” signals released by HCs, as well as CD31, CD47, and CD46 “don’t eat me” signaling molecules, trigger initiation of innate immunity, which serves to regulate phagocytosis. Additionally, HC-mediated trogocytosis promotes antigen presentation and amplification. Importantly, HC-mediated CD4+ T lymphocyte activation is critical in the transition of the innate immune response to adaptive immunity. HCs also mediate non-specific transcytosis of antibodies produced by mature B lymphocytes, for instance, IgA transcytosis in ovarian cancer cells, which triggers innate immunity. Further understanding of the interplay between HCs/GJs and IGLDCPs would aid in identifying therapeutic targets that regulate the HC–Ig-like domain immune response, thereby providing a viable treatment strategy for immunological diseases. The present review delineates the clinical immunology-related applications of HC–Ig-like domain cross-activation, which would greatly benefit medical professionals and immunological researchers alike. HCs/GJs and IGLDCPs mediate phagocytosis via ATP; “eat me and don’t eat me” signals trigger innate immunity; HC-mediated trogocytosis promotes antigen presentation and amplification in innate–adaptive immunity; HCs also mediate non-specific transcytosis of antibodies produced by mature B lymphocytes in adaptive immunity.
Collapse
Affiliation(s)
- Jiang-Hui Meng
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, China
| | - Chang-Xu Chen
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, China
| | - Mohammad R. Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Hong Zan
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center, San Antonio, TX, United States
| | - Kai-Jun Luo
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory of the University in Yunnan Province for International Cooperation in Intercellular Communications and Regulations, Yunnan University, Kunming, China
- *Correspondence: Kai-Jun Luo, ; Jean X. Jiang,
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
- *Correspondence: Kai-Jun Luo, ; Jean X. Jiang,
| |
Collapse
|
4
|
Choi C, Saha A, An S, Cho YK, Kim H, Noh M, Lee YH. Macrophage-Specific Connexin 43 Knockout Protects Mice from Obesity-Induced Inflammation and Metabolic Dysfunction. Front Cell Dev Biol 2022; 10:925971. [PMID: 35800892 PMCID: PMC9253378 DOI: 10.3389/fcell.2022.925971] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022] Open
Abstract
Adipose tissue macrophages are a major immune cell type contributing to homeostatic maintenance and pathological adipose tissue remodeling. However, the mechanisms underlying macrophage recruitment and polarization in adipose tissue during obesity remain poorly understood. Previous studies have suggested that the gap junctional protein, connexin 43 (Cx43), plays a critical role in macrophage activation and phagocytosis. Herein, we investigated the macrophage-specific roles of Cx43 in high fat diet (HFD)-induced pathological remodeling of adipose tissue. Expression levels of Cx43 were upregulated in macrophages co-cultured with dying adipocytes in vitro, as well as in macrophages associated with dying adipocytes in the adipose tissue of HFD-fed mice. Cx43 knockdown reduced lipopolysaccharide (LPS)-induced ATP release from macrophages and decreased inflammatory responses of macrophages co-cultured with dying adipocytes. Based on global gene expression profiling, macrophage-specific Cx43-knockout (Cx43-MKO) mice were resistant to HFD-induced inflammatory responses in adipose tissue, potentially via P2X7-mediated signaling pathways. Cx43-MKO mice exhibited reduced HFD-induced macrophage recruitment in adipose tissue. Moreover, Cx43-MKO mice showed reduced inflammasome activation in adipose tissues and improved glucose tolerance. Collectively, these findings demonstrate that Cx43 expression in macrophages facilitates inflammasome activation, which, in turn, contributes to HFD-induced metabolic dysfunction.
Collapse
|
5
|
Gap Junction-Dependent and -Independent Functions of Connexin43 in Biology. BIOLOGY 2022; 11:biology11020283. [PMID: 35205149 PMCID: PMC8869330 DOI: 10.3390/biology11020283] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 12/21/2022]
Abstract
For the first time in animal evolution, the emergence of gap junctions allowed direct exchanges of cellular substances for communication between two cells. Innexin proteins constituted primordial gap junctions until the connexin protein emerged in deuterostomes and took over the gap junction function. After hundreds of millions of years of gene duplication, the connexin gene family now comprises 21 members in the human genome. Notably, GJA1, which encodes the Connexin43 protein, is one of the most widely expressed and commonly studied connexin genes. The loss of Gja1 in mice leads to swelling and a blockage of the right ventricular outflow tract and death of the embryos at birth, suggesting a vital role of Connexin43 gap junction in heart development. Since then, the importance of Connexin43-mediated gap junction function has been constantly expanded to other types of cells. Other than forming gap junctions, Connexin43 can also form hemichannels to release or uptake small molecules from the environment or even mediate many physiological processes in a gap junction-independent manner on plasma membranes. Surprisingly, Connexin43 also localizes to mitochondria in the cell, playing important roles in mitochondrial potassium import and respiration. At the molecular level, Connexin43 mRNA and protein are processed with very distinct mechanisms to yield carboxyl-terminal fragments with different sizes, which have their unique subcellular localization and distinct biological activities. Due to many exciting advancements in Connexin43 research, this review aims to start with a brief introduction of Connexin43 and then focuses on updating our knowledge of its gap junction-independent functions.
Collapse
|
6
|
Tittarelli A. Connexin channels modulation in pathophysiology and treatment of immune and inflammatory disorders. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166258. [PMID: 34450245 DOI: 10.1016/j.bbadis.2021.166258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/28/2021] [Accepted: 08/19/2021] [Indexed: 12/16/2022]
Abstract
Connexin-mediated intercellular communication mechanisms include bidirectional cell-to-cell coupling by gap junctions and release/influx of molecules by hemichannels. These intercellular communications have relevant roles in numerous immune system activities. Here, we review the current knowledge about the function of connexin channels, mainly those formed by connexin-43, on immunity and inflammation. Focusing on those evidence that support the design and development of therapeutic tools to modulate connexin expression and/or channel activities with treatment potential for infections, wounds, cancer, and other inflammatory conditions.
Collapse
Affiliation(s)
- Andrés Tittarelli
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Santiago 8940577, Chile.
| |
Collapse
|
7
|
Structural, functional, and mechanistic insights uncover the fundamental role of orphan connexin-62 in platelets. Blood 2021; 137:830-843. [PMID: 32822477 DOI: 10.1182/blood.2019004575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 08/13/2020] [Indexed: 12/14/2022] Open
Abstract
Connexins oligomerise to form hexameric hemichannels in the plasma membrane that can further dock together on adjacent cells to form gap junctions and facilitate intercellular trafficking of molecules. In this study, we report the expression and function of an orphan connexin, connexin-62 (Cx62), in human and mouse (Cx57, mouse homolog) platelets. A novel mimetic peptide (62Gap27) was developed to target the second extracellular loop of Cx62, and 3-dimensional structural models predicted its interference with gap junction and hemichannel function. The ability of 62Gap27 to regulate both gap junction and hemichannel-mediated intercellular communication was observed using fluorescence recovery after photobleaching analysis and flow cytometry. Cx62 inhibition by 62Gap27 suppressed a range of agonist-stimulated platelet functions and impaired thrombosis and hemostasis. This was associated with elevated protein kinase A-dependent signaling in a cyclic adenosine monophosphate-independent manner and was not observed in Cx57-deficient mouse platelets (in which the selectivity of 62Gap27 for this connexin was also confirmed). Notably, Cx62 hemichannels were observed to function independently of Cx37 and Cx40 hemichannels. Together, our data reveal a fundamental role for a hitherto uncharacterized connexin in regulating the function of circulating cells.
Collapse
|
8
|
Rodjakovic D, Salm L, Beldi G. Function of Connexin-43 in Macrophages. Int J Mol Sci 2021; 22:1412. [PMID: 33573367 PMCID: PMC7866802 DOI: 10.3390/ijms22031412] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 12/14/2022] Open
Abstract
Recent studies have helped to increase the understanding of the function of Connexin-43 (Cx43) in macrophages (Mφ). The various roles of Cx43 in Mφs range from migration, antigen-presentation and some forms of intercellular communication to more delicate processes, such as electrochemical support in the propagation of the heartbeat, immunomodulatory regulation in the lungs and in macrophage-differentiation. Its relevance in pathophysiology becomes evident in inflammatory bowel disease (IBD), tumours and HIV, in which aberrant functioning of Cx43 has been described. However, the involvement of Cx43 in other Mφ functions, such as phagocytosis and polarisation, and its involvement in other types of local and systemic inflammation, are still unclear and need further research.
Collapse
Affiliation(s)
- Daniel Rodjakovic
- Department for Visceral Surgery and Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (D.R.); (L.S.)
- Department for BioMedical Research (DBMR), Bern University Hospital, University of Bern, CH-3008 Bern, Switzerland
| | - Lilian Salm
- Department for Visceral Surgery and Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (D.R.); (L.S.)
- Department for BioMedical Research (DBMR), Bern University Hospital, University of Bern, CH-3008 Bern, Switzerland
| | - Guido Beldi
- Department for Visceral Surgery and Medicine, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; (D.R.); (L.S.)
- Department for BioMedical Research (DBMR), Bern University Hospital, University of Bern, CH-3008 Bern, Switzerland
| |
Collapse
|
9
|
The Role of Connexin 43 in Lung Disease. Life (Basel) 2020; 10:life10120363. [PMID: 33352732 PMCID: PMC7766413 DOI: 10.3390/life10120363] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 01/10/2023] Open
Abstract
The term lung disease describes a broad category of disorders that impair lung function. More than 35 million Americans have a preventable chronic lung disease with high mortality rates due to limited treatment efficacy. The recent increase in patients with lung disease highlights the need to increase our understanding of mechanisms driving lung inflammation. Connexins, gap junction proteins, and more specifically connexin 43 (Cx43), are abundantly expressed in the lung and are known to play a role in lung diseases. This review focuses on the role of Cx43 in pathology associated with acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD) and asthma. Additionally, we discuss the role of Cx43 in preventing disease through the transfer of mitochondria between cells. We aim to highlight the need to better understand what cell types are expressing Cx43 and how this expression influences lung disease.
Collapse
|
10
|
Guo Y, Chen H, Wang QJ, Qi X, Li Q, Fu W, Huang J, Yao CY, Liu ZY, Wang MZ, An L, Tian JH, Wu ZH. Prolonged melatonin treatment promote testicular recovery by enhancing RAC1-mediated apoptotic cell clearance and cell junction-dependent spermatogensis after heat stress. Theriogenology 2020; 162:22-31. [PMID: 33418161 DOI: 10.1016/j.theriogenology.2020.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 12/08/2020] [Accepted: 12/12/2020] [Indexed: 12/13/2022]
Abstract
INTRODUCTION A decline in semen quality caused by global warming and torrid working conditions is a major cause of human male infertility, and heat stress-induced decreases in male reproductive ability results in economic losses in livestock husbandry. Increasing evidence suggests that melatonin exerts protective effects on stress-induced DNA damage and apoptosis in germ cells. However, few studies have assessed the effects of melatonin on testicular recovery during post-heat stress and the underlying mechanisms. METHODS AND RESULTS In vivo studies using 8-week-old male CD-1 mice revealed that melatonin pretreatment (50 mg/kg for 5 days) did not alleviate heat stress-induced germ cell loss and disrupted testicular histomorphology, however, long-term melatonin administration after heat stress accelerated germ cell apoptosis, spermatogenic cell regeneration, and testicular weight recovery. In vitro studies demonstrated that melatonin enhanced RAC1 activity, resulting in increased phagocytosis of apoptotic germ cells by Sertoli cells. In addition, melatonin restored gap junctions and tight junctions after heat stress, thereby promoting hollow seminiferous tubule filling. DISCUSSION Long-term melatonin administration accelerated testicular recovery after heat stress by enhancing the phagocytotic activity of Sertoli cells and the regeneration of spermatogenic cells. This finding suggests that melatonin is a potential therapeutic for heat stress-induced male infertility.
Collapse
Affiliation(s)
- Yao Guo
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Hui Chen
- College of Animal Science and Technology, Hebei Agricultural University, Baoding, 071000, China
| | - Qiang-Jun Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Xin Qi
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Qin Li
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Wei Fu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Jie Huang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Chun-Yan Yao
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Zhong-Ying Liu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Mei-Zhi Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Lei An
- National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Jian-Hui Tian
- National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Zhong-Hong Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
| |
Collapse
|
11
|
Li X, Nagy JI, Li D, Acott TS, Kelley MJ. Gap junction connexin43 is a key element in mediating phagocytosis activity in human trabecular meshwork cells. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2020; 12:25-31. [PMID: 32211119 PMCID: PMC7076328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
Human trabecular meshwork (TM) cells play pivotal roles in maintaining homeostasis of intraocular pressure via regulation of aqueous humor outflow. These cells are capable of phagocytosis, which is considered to be essential for their regulatory function. In addition, there is a strong expression of the gap junction protein connexin43 (Cx43) in the TM. Here, we investigated functional relationships between phagocytosis activity of TM cells and their expression of Cx43. Phagocytosis was measured by showing the ability of TM cells to engulf inert fluorescent particles consisting of pHrodo. We found that internalized pHrodo was partially co-localized with Cx43 and that the phagocytic activity was dramatically reduced after knockdown of Cx43 using lentiviral Cx43 shRNA. These results suggest that Cx43 is involved in the regulation of phagocytosis by TM cells.
Collapse
Affiliation(s)
- Xinbo Li
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science UniversityPortland, Oregon, USA
| | - James I Nagy
- Department of Physiology and Pathophysiology, University of ManitobaWinnipeg, MB, Canada
| | - Davey Li
- University of WaterlooWaterloo, ON, Canada
| | - Ted S Acott
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science UniversityPortland, Oregon, USA
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science UniversityPortland, Oregon, USA
| | - Mary J Kelley
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science UniversityPortland, Oregon, USA
- Department of Integrative Biosciences, Oregon Health & Science UniversityPortland, Oregon, USA
| |
Collapse
|
12
|
Dosch M, Zindel J, Jebbawi F, Melin N, Sanchez-Taltavull D, Stroka D, Candinas D, Beldi G. Connexin-43-dependent ATP release mediates macrophage activation during sepsis. eLife 2019; 8:42670. [PMID: 30735126 PMCID: PMC6415938 DOI: 10.7554/elife.42670] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/05/2019] [Indexed: 12/11/2022] Open
Abstract
Bacterial spillage into a sterile environment following intestinal hollow-organ perforation leads to peritonitis and fulminant sepsis. Outcome of sepsis critically depends on macrophage activation by extracellular ATP-release and associated autocrine signalling via purinergic receptors. ATP-release mechanisms, however, are poorly understood. Here, we show that TLR-2 and −4 agonists trigger ATP-release via Connexin-43 hemichannels in macrophages leading to poor sepsis survival. In humans, Connexin-43 was upregulated on macrophages isolated from the peritoneal cavity in patients with peritonitis but not in healthy controls. Using a murine peritonitis/sepsis model, we identified increased Connexin-43 expression in peritoneal and hepatic macrophages. Conditional Lyz2cre/creGja1flox/flox mice were developed to specifically assess Connexin-43 impact in macrophages. Both macrophage-specific Connexin-43 deletion and pharmacological Connexin-43 blockade were associated with reduced cytokine secretion by macrophages in response to LPS and CLP, ultimately resulting in increased survival. In conclusion, inhibition of autocrine Connexin-43-dependent ATP signalling on macrophages improves sepsis outcome.
Collapse
Affiliation(s)
- Michel Dosch
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Joël Zindel
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Fadi Jebbawi
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Nicolas Melin
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | | | - Deborah Stroka
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Daniel Candinas
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Guido Beldi
- Department for BioMedical Research, University of Bern, Bern, Switzerland
| |
Collapse
|
13
|
Shen C, Chen JH, Lee Y, Hassan MM, Kim SJ, Choi EY, Hong ST, Park BH, Park JH. mTOR- and SGK-Mediated Connexin 43 Expression Participates in Lipopolysaccharide-Stimulated Macrophage Migration through the iNOS/Src/FAK Axis. THE JOURNAL OF IMMUNOLOGY 2018; 201:2986-2997. [DOI: 10.4049/jimmunol.1700954] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/12/2018] [Indexed: 01/08/2023]
|
14
|
Johnson RD, Camelliti P. Role of Non-Myocyte Gap Junctions and Connexin Hemichannels in Cardiovascular Health and Disease: Novel Therapeutic Targets? Int J Mol Sci 2018; 19:ijms19030866. [PMID: 29543751 PMCID: PMC5877727 DOI: 10.3390/ijms19030866] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 03/10/2018] [Accepted: 03/12/2018] [Indexed: 12/24/2022] Open
Abstract
The heart is a complex organ composed of multiple cell types, including cardiomyocytes and different non-myocyte populations, all working closely together to determine the hearts properties and maintain normal cardiac function. Connexins are abundantly expressed proteins that form plasma membrane hemichannels and gap junctions between cells. Gap junctions are intracellular channels that allow for communication between cells, and in the heart they play a crucial role in cardiac conduction by coupling adjacent cardiomyocytes. Connexins are expressed in both cardiomyocytes and non-myocytes, including cardiac fibroblasts, endothelial cells, and macrophages. Non-myocytes are the largest population of cells in the heart, and therefore it is important to consider what roles connexins, hemichannels, and gap junctions play in these cell types. The aim of this review is to provide insight into connexin-based signalling in non-myocytes during health and disease, and highlight how targeting these proteins could lead to the development of novel therapies. We conclude that connexins in non-myocytes contribute to arrhythmias and adverse ventricular remodelling following myocardial infarction, and are associated with the initiation and development of atherosclerosis. Therefore, therapeutic interventions targeting these connexins represent an exciting new research avenue with great potential.
Collapse
Affiliation(s)
- Robert D Johnson
- School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK.
| | - Patrizia Camelliti
- School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, UK.
| |
Collapse
|
15
|
Gleisner MA, Navarrete M, Hofmann F, Salazar-Onfray F, Tittarelli A. Mind the Gaps in Tumor Immunity: Impact of Connexin-Mediated Intercellular Connections. Front Immunol 2017; 8:1067. [PMID: 28919895 PMCID: PMC5585150 DOI: 10.3389/fimmu.2017.01067] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 08/16/2017] [Indexed: 12/22/2022] Open
Abstract
Gap junctions (GJs)-mediated intercellular communications (GJICs) are connexin (Cx)-formed plasma membrane channels that allow for the passage of small molecules between adjacent cells, and are involved in several physiopathological processes, including immune responses against cancer. In general, tumor cells are poorly coupled through GJs, mainly due to low Cx expression or reduced channel activity, suggesting that Cxs may have tumor suppressor roles. However, more recent data indicate that Cxs and/or GJICs may also in some cases promote tumor progression. This dual role of Cx channels in tumor outcome may be due, at least partially, to the fact that GJs not only interconnect cells from the same type, such as cancer cells, but also promote the intercellular communication of tumor cells with different types of cells from their microenvironment, and such diverse intercellular interactions have distinctive impact on tumor development. For example, whereas GJ-mediated interactions among tumor cells and microglia have been implicated in promotion of tumor growth, tumor cells delivery to dendritic cells of antigenic peptides through GJs have been associated with enhanced immune-mediated tumor elimination. In this review, we provide an updated overview on the role of GJICs in tumor immunity, focusing on the pro-tumor and antitumor effect of GJs occurring among tumor and immune cells. Accumulated data suggest that GJICs may act as tumor suppressors or enhancers depending on whether tumor cells interact predominantly with antitumor immune cells or with stromal cells. The complex modulation of immune-tumor cell GJICs should be taken into consideration in order to potentiate current cancer immunotherapies.
Collapse
Affiliation(s)
- María Alejandra Gleisner
- Disciplinary Program of Immunology, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Faculty of Medicine, Millennium Institute on Immunology and Immunotherapy, Universidad de Chile, Santiago, Chile
| | - Mariela Navarrete
- Disciplinary Program of Immunology, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Faculty of Medicine, Millennium Institute on Immunology and Immunotherapy, Universidad de Chile, Santiago, Chile
| | - Francisca Hofmann
- Disciplinary Program of Immunology, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Faculty of Medicine, Millennium Institute on Immunology and Immunotherapy, Universidad de Chile, Santiago, Chile
| | - Flavio Salazar-Onfray
- Disciplinary Program of Immunology, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Faculty of Medicine, Millennium Institute on Immunology and Immunotherapy, Universidad de Chile, Santiago, Chile
| | - Andrés Tittarelli
- Disciplinary Program of Immunology, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Faculty of Medicine, Millennium Institute on Immunology and Immunotherapy, Universidad de Chile, Santiago, Chile
| |
Collapse
|
16
|
Kou Y, Ji L, Wang H, Wang W, Zheng H, Zou J, Liu L, Qi X, Liu Z, Du B, Lu L. Connexin 43 upregulation by dioscin inhibits melanoma progression via suppressing malignancy and inducing M1 polarization. Int J Cancer 2017; 141:1690-1703. [DOI: 10.1002/ijc.30872] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/21/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Yu Kou
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
- Department of Pathology; School of Basic Medical Sciences, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Liyan Ji
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Haojia Wang
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Wensheng Wang
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Hongming Zheng
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Juan Zou
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Linxin Liu
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Xiaoxiao Qi
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Zhongqiu Liu
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Biaoyan Du
- Department of Pathology; School of Basic Medical Sciences, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| | - Linlin Lu
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine; Guangzhou 510006 China
| |
Collapse
|
17
|
Li S, Peng W, Chen X, Geng X, Zhan W, Sun J. Expression and role of gap junction protein connexin43 in immune challenge-induced extracellular ATP release in Japanese flounder (Paralichthys olivaceus). FISH & SHELLFISH IMMUNOLOGY 2016; 55:348-357. [PMID: 27291350 DOI: 10.1016/j.fsi.2016.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 06/02/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
Connexin43 (Cx43) is the best characterized gap junction protein that allows the direct exchange of signaling molecules during cell-to-cell communications. The immunological functions and ATP permeable properties of Cx43 have been insensitively examined in mammals. The similar biological significance of Cx43 in lower vertebrates, however, is not yet understood. In the present study we identified and characterized a Cx43 ortholog (termed PoCx43) from Japanese flounder (Paralichthys olivaceus) and investigated its role in immune challenge-induced extracellular ATP release. PoCx43 mRNA transcripts are widely distributed in all tested normal tissues and cells with predominant expression in the brain, and are significantly up-regulated by LPS, poly(I:C) and zymosan challenges and Edwardsiella tarda infections as well, suggesting that PoCx43 expression was modulated by the inflammatory stresses. In addition, cyclic AMP (cAMP), an essential second messenger, also plays an important role in regulating PoCx43 gene expression, by which the PoCx43-mediated gap junctional communication may be regulated. Furthermore, overexpression of PoCx43 in Japanese flounder FG-9307 cells significantly potentiates the LPS- and poly(I:C)-induced extracellular ATP release and this enhanced ATP release was attenuated by pre-incubation with Cx43 inhibitor carbenoxolone. In a complementary experiment, down-regulation of PoCx43 endogenous expression in FG-9307 cells with small interfering RNA also significantly reduced the PAMP-induced extracellular ATP release, suggesting that PoCx43 is an important ATP release conduit under the immune challenge conditions. Finally, we showed that extracellular ATP stimulation led to an increased PoCx43 expression which probably provides a feedback mechanism in regulating PoCx43 expression at the transcriptional level. These findings suggest that PoCx43 is an inducible immune response gene and an important conduit for immune challenge-induced extracellular ATP release in fish.
Collapse
Affiliation(s)
- Shuo Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China.
| | - Weijiao Peng
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China
| | - Xiaoli Chen
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China
| | - Xuyun Geng
- Tianjin Center for Control and Prevention of Aquatic Animal Infectious Disease, 442 South Jiefang Road, Hexi District, Tianjin 300221, China
| | - Wenbin Zhan
- Laboratory of Pathology and Immunology of Aquatic Animals, LMMEC, Ocean University of China, Qingdao 266003, China
| | - Jinsheng Sun
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China.
| |
Collapse
|
18
|
Fu PC, Tang RH, Wan Y, Xie MJ, Wang W, Luo X, Yu ZY. ROCK inhibition with fasudil promotes early functional recovery of spinal cord injury in rats by enhancing microglia phagocytosis. ACTA ACUST UNITED AC 2016; 36:31-36. [DOI: 10.1007/s11596-016-1537-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 10/13/2015] [Indexed: 02/06/2023]
|
19
|
Rho-Associated Kinase Inhibitors Promote Microglial Uptake Via the ERK Signaling Pathway. Neurosci Bull 2016; 32:83-91. [PMID: 26779919 DOI: 10.1007/s12264-016-0013-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/26/2015] [Indexed: 12/17/2022] Open
Abstract
Microglia are immunocompetent cells in the central nervous system that take up tissue debris and pathogens. Rho-associated kinase (ROCK) has been identified as an important regulator of uptake, proliferation, secretion, and differentiation in a number of cell types. Although ROCK plays critical roles in the microglial secretion of inflammatory factors, migration, and morphology, its effects on microglial uptake activity have not been well characterized. In the present study, we found that treatment of BV2 microglia and primary microglia with the ROCK inhibitors Y27632 and fasudil increased uptake activity and was associated with morphological changes. Furthermore, western blots showed that this increase in uptake activity was mediated through the extracellular-signal-regulated kinase (ERK) signaling cascade, indicating the importance of ROCK in regulating microglial uptake activity.
Collapse
|
20
|
Glass AM, Snyder EG, Taffet SM. Connexins and pannexins in the immune system and lymphatic organs. Cell Mol Life Sci 2015; 72:2899-910. [PMID: 26100515 PMCID: PMC11113820 DOI: 10.1007/s00018-015-1966-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 06/11/2015] [Indexed: 12/11/2022]
Abstract
Connexin43 and pannexin1 are found in immune cells. While gap junctional communication has been demonstrated between immune cells, hemichannels have been implicated in many cellular functions. Among the functions involved as being connexin dependent and pannexin dependent are cell migration, phagocytosis, antigen presentation, T-cell reactivity and B-cell responses. Surprisingly, many of these connexin-related and pannexin-related functions are not recapitulated in in vivo models. This is leading to a reevaluation of the role of these proteins in immune function.
Collapse
Affiliation(s)
- Aaron M. Glass
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 750 E Adams Street, Syracuse, NY 13210 USA
| | - Elizabeth G. Snyder
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 750 E Adams Street, Syracuse, NY 13210 USA
| | - Steven M. Taffet
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 750 E Adams Street, Syracuse, NY 13210 USA
| |
Collapse
|
21
|
Sáez PJ, Shoji KF, Aguirre A, Sáez JC. Regulation of hemichannels and gap junction channels by cytokines in antigen-presenting cells. Mediators Inflamm 2014; 2014:742734. [PMID: 25301274 PMCID: PMC4180397 DOI: 10.1155/2014/742734] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 06/19/2014] [Indexed: 12/13/2022] Open
Abstract
Autocrine and paracrine signals coordinate responses of several cell types of the immune system that provide efficient protection against different challenges. Antigen-presenting cells (APCs) coordinate activation of this system via homocellular and heterocellular interactions. Cytokines constitute chemical intercellular signals among immune cells and might promote pro- or anti-inflammatory effects. During the last two decades, two membrane pathways for intercellular communication have been demonstrated in cells of the immune system. They are called hemichannels (HCs) and gap junction channels (GJCs) and provide new insights into the mechanisms of the orchestrated response of immune cells. GJCs and HCs are permeable to ions and small molecules, including signaling molecules. The direct intercellular transfer between contacting cells can be mediated by GJCs, whereas the release to or uptake from the extracellular milieu can be mediated by HCs. GJCs and HCs can be constituted by two protein families: connexins (Cxs) or pannexins (Panxs), which are present in almost all APCs, being Cx43 and Panx1 the most ubiquitous members of each protein family. In this review, we focus on the effects of different cytokines on the intercellular communication mediated by HCs and GJCs in APCs and their impact on purinergic signaling.
Collapse
Affiliation(s)
- Pablo J. Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Alameda 340, 6513677 Santiago, Chile
| | - Kenji F. Shoji
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Alameda 340, 6513677 Santiago, Chile
| | - Adam Aguirre
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Alameda 340, 6513677 Santiago, Chile
| | - Juan C. Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Alameda 340, 6513677 Santiago, Chile
- Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso, Pasaje Harrington 287, Playa Ancha, 2360103 Valparaíso, Chile
| |
Collapse
|
22
|
Guo CX, Tran H, Green CR, Danesh-Meyer HV, Acosta ML. Gap junction proteins in the light-damaged albino rat. Mol Vis 2014; 20:670-82. [PMID: 24883012 PMCID: PMC4037536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Accepted: 05/24/2014] [Indexed: 12/01/2022] Open
Abstract
PURPOSE Changes in connexin expression are associated with many pathological conditions seen in animal models and in humans. We hypothesized that gap junctions are important mediators in tissue dysfunction and injury processes in the retina, and therefore, we investigated the pattern of connexin protein expression in the light-damaged albino rat eye. METHODS Adult Sprague-Dawley rats were exposed to intense light for 24 h. The animals were euthanized, and ocular tissue was harvested at 0 h, 6 h, 24 h, 48 h, and 7 days after light damage. The tissues were processed for immunohistochemistry and western blotting to analyze the expression of the gap junction proteins in the light-damaged condition compared to the non-light-damaged condition. Cell death was detected using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) technique. RESULTS Intense light exposure caused increased TUNEL labeling of photoreceptor cells. Immunocytochemistry revealed that connexin 36 (Cx36) was significantly increased in the inner plexiform layer and Cx45 was significantly decreased in the light-damaged retina. The pattern of Cx36 and Cx45 labeling returned to normal 7 days after light damage. Cx43 significantly increased in the RPE and the choroid in the light-damaged tissue, and decreased but not significantly in the retina. This elevated Cx43 expression in the choroid colocalized with markers of nitration-related oxidative stress (nitrotyrosine) and inflammation (CD45 and ionized calcium-binding adaptor molecule-1) in the choroid. CONCLUSIONS The results suggest that connexins are regulated differently in the retina than in the choroid in response to photoreceptor damage. Changes in connexins, including Cx36, Cx43, and Cx45, may contribute to the damage process. Specifically, Cx43 was associated with inflammatory damage. Therefore, connexins may be candidate targets for treatment for ameliorating disease progression.
Collapse
Affiliation(s)
- Cindy X Guo
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand ; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Henry Tran
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand ; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Helen V Danesh-Meyer
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand ; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Monica L Acosta
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand ; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| |
Collapse
|
23
|
Castellano P, Eugenin EA. Regulation of gap junction channels by infectious agents and inflammation in the CNS. Front Cell Neurosci 2014; 8:122. [PMID: 24847208 PMCID: PMC4023065 DOI: 10.3389/fncel.2014.00122] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 04/17/2014] [Indexed: 01/04/2023] Open
Abstract
Gap junctions (GJs) are conglomerates of intercellular channels that connect the cytoplasm of two or more cells, and facilitate the transfer of ions and small molecules, including second messengers, resulting in metabolic and electrical coordination. In general, loss of gap junctional communication (GJC) has been associated with cellular damage and inflammation resulting in compromise of physiological functions. Recently, it has become evident that GJ channels also play a critical role in the pathogenesis of infectious diseases and associated inflammation. Several pathogens use the transfer of intracellular signals through GJ channels to spread infection and toxic signals that amplify inflammation to neighboring cells. Thus, identification of the mechanisms by which several infectious agents alter GJC could result in new potential therapeutic approaches to reduce inflammation and their pathogenesis.
Collapse
Affiliation(s)
- Paul Castellano
- Public Health Research Institute (PHRI), New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA ; Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA
| | - Eliseo A Eugenin
- Public Health Research Institute (PHRI), New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA ; Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA
| |
Collapse
|
24
|
Inhibition of GSK-3β rescues the impairments in bone formation and mechanical properties associated with fracture healing in osteoblast selective connexin 43 deficient mice. PLoS One 2013; 8:e81399. [PMID: 24260576 PMCID: PMC3832658 DOI: 10.1371/journal.pone.0081399] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/22/2013] [Indexed: 12/12/2022] Open
Abstract
Connexin 43 (Cx43) is the most abundant gap junction protein in bone and is required for osteoblastic differentiation and bone homeostasis. During fracture healing, Cx43 is abundantly expressed in osteoblasts and osteocytes, while Cx43 deficiency impairs bone formation and healing. In the present study we selectively deleted Cx43 in the osteoblastic lineage from immature osteoblasts through osteocytes and tested the hypothesis that Cx43 deficiency results in delayed osteoblastic differentiation and impaired restoration of biomechanical properties due to attenuated β-catenin expression relative to wild type littermates. Here we show that Cx43 deficiency results in alterations in the mineralization and remodeling phases of healing. In Cx43 deficient fractures the mineralization phase is marked by delayed expression of osteogenic genes. Additionally, the decrease in the RankL/ Opg ratio, osteoclast number and osteoclast size suggest decreased osteoclast bone resorption and remodeling. These changes in healing result in functional deficits as shown by a decrease in ultimate torque at failure. Consistent with these impairments in healing, β-catenin expression is attenuated in Cx43 deficient fractures at 14 and 21 days, while Sclerostin (Sost) expression, a negative regulator of bone formation is increased in Cx43cKO fractures at 21 days, as is GSK-3β, a key component of the β-catenin proteasomal degradation complex. Furthermore, we show that alterations in healing in Cx43 deficient fractures can be rescued by inhibiting GSK-3β activity using Lithium Chloride (LiCl). Treatment of Cx43 deficient mice with LiCl restores both normal bone formation and mechanical properties relative to LiCl treated WT fractures. This study suggests that Cx43 is a potential therapeutic target to enhance fracture healing and identifies a previously unknown role for Cx43 in regulating β-catenin expression and thus bone formation during fracture repair.
Collapse
|
25
|
Suram S, Silveira LJ, Mahaffey S, Brown GD, Bonventre JV, Williams DL, Gow NAR, Bratton DL, Murphy RC, Leslie CC. Cytosolic phospholipase A(2)α and eicosanoids regulate expression of genes in macrophages involved in host defense and inflammation. PLoS One 2013; 8:e69002. [PMID: 23950842 PMCID: PMC3742295 DOI: 10.1371/journal.pone.0069002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 06/03/2013] [Indexed: 12/20/2022] Open
Abstract
The role of Group IVA cytosolic phospholipase A2 (cPLA2α)
activation in regulating macrophage transcriptional responses to
Candida
albicans infection was investigated.
cPLA2α releases arachidonic acid for the production of
eicosanoids. In mouse resident peritoneal macrophages, prostacyclin,
prostaglandin E2 and leukotriene C4 were produced within
minutes of C.
albicans addition before cyclooxygenase 2
expression. The production of TNFα was lower in C.
albicans-stimulated cPLA2α+/+
than cPLA2α-/- macrophages due to an autocrine effect of
prostaglandins that increased cAMP to a greater extent in
cPLA2α+/+ than cPLA2α-/-
macrophages. For global insight, differential gene expression in
C.
albicans-stimulated
cPLA2α+/+ and cPLA2α-/-
macrophages (3 h) was compared by microarray. cPLA2α+/+
macrophages expressed 86 genes at lower levels and 181 genes at higher levels
than cPLA2α-/- macrophages (≥2-fold, p<0.05). Several
pro-inflammatory genes were expressed at lower levels (Tnfα,
Cx3cl1, Cd40, Ccl5,
Csf1, Edn1, CxCr7, Irf1,
Irf4, Akna, Ifnγ, several IFNγ-inducible
GTPases). Genes that dampen inflammation (Socs3,
Il10, Crem, Stat3,
Thbd, Thbs1, Abca1) and
genes involved in host defense (Gja1, Csf3,
Trem1, Hdc) were expressed at higher
levels in cPLA2α+/+ macrophages. Representative genes
expressed lower in cPLA2α+/+ macrophages (Tnfα,
Csf1) were increased by treatment with a prostacyclin receptor
antagonist and protein kinase A inhibitor, whereas genes expressed at higher
levels (Crem, Nr4a2, Il10,
Csf3) were suppressed. The results suggest that
C.
albicans stimulates an autocrine loop in
macrophages involving cPLA2α, cyclooxygenase 1-derived prostaglandins
and increased cAMP that globally effects expression of genes involved in host
defense and inflammation.
Collapse
Affiliation(s)
- Saritha Suram
- Department of Pediatrics, National Jewish Health, Denver, Colorado,
United States of America
| | - Lori J. Silveira
- Division of Biostatistics and Bioinformatics, National Jewish Health,
Denver, Colorado, United States of America
| | - Spencer Mahaffey
- Department of Pediatrics, National Jewish Health, Denver, Colorado,
United States of America
| | - Gordon D. Brown
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United
Kingdom
| | - Joseph V. Bonventre
- Renal Division, Brigham and Women’s Hospital, Boston, Massachusetts,
United States of America
| | - David L. Williams
- Department of Surgery, James H. Quillen College of Medicine, Johnson
City, Tennessee, United States of America
| | - Neil A. R. Gow
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United
Kingdom
| | - Donna L. Bratton
- Department of Pediatrics, National Jewish Health, Denver, Colorado,
United States of America
| | - Robert C. Murphy
- Department of Pharmacology, University of Colorado Denver, Aurora,
Colorado, United States of America
| | - Christina C. Leslie
- Department of Pediatrics, National Jewish Health, Denver, Colorado,
United States of America
- Department of Pharmacology, University of Colorado Denver, Aurora,
Colorado, United States of America
- Department of Pathology, University of Colorado Denver, Aurora, Colorado,
United States of America
- * E-mail:
| |
Collapse
|
26
|
Glass AM, Wolf BJ, Schneider KM, Princiotta MF, Taffet SM. Connexin43 is dispensable for phagocytosis. THE JOURNAL OF IMMUNOLOGY 2013; 190:4830-5. [PMID: 23554311 DOI: 10.4049/jimmunol.1202884] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Macrophages that lack connexin43 (Cx43), a gap junction protein, have been reported to exhibit dramatic deficiencies in phagocytosis. In this study, we revisit these findings using well-characterized macrophage populations. Cx43 knockout (Cx43(-/-)) mice die soon after birth, making the harvest of macrophages from adult Cx43(-/-) mice problematic. To overcome this obstacle, we used several strategies: mice heterozygous for the deletion of Cx43 were crossed to produce Cx43(+/+) (wild type [WT]) and Cx43(-/-) fetuses. Cells isolated from 12- to 14-d fetal livers were used to reconstitute irradiated recipient animals. After reconstitution, thioglycollate-elicited macrophages were collected by peritoneal lavage and bone marrow was harvested. Bone marrow cells and, alternatively, fetal liver cells were cultured in media containing M-CSF for 7-10 d, resulting in populations of cells that were >95% macrophages based on flow cytometry. Phagocytic uptake was detected using flow cytometric and microscopic techniques. Quantification of phagocytic uptake of IgG-opsonized sheep erythrocytes, zymosan particles, and Listeria monocytogenes failed to show any significant difference between WT and Cx43(-/-) macrophages. Furthermore, the use of particles labeled with pH-sensitive dyes showed equivalent acidification of phagosomes in both WT and Cx43(-/-) macrophages. Our findings suggest that modulation of Cx43 levels in cultured macrophages does not have a significant impact on phagocytosis.
Collapse
Affiliation(s)
- Aaron M Glass
- Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | | | | | | | | |
Collapse
|
27
|
The Wingless homolog Wnt5a stimulates phagocytosis but not bacterial killing. Proc Natl Acad Sci U S A 2012; 109:16600-5. [PMID: 23012420 DOI: 10.1073/pnas.1207789109] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Phagocytosis is a primary defense program orchestrated by monocytes/macrophages. Unregulated phagocytosis can lead to pathological conditions. In the current study we have demonstrated that Wnt5a stimulates phagocytosis through PI3 kinase-Rac1 and lipid-raft-dependent processes. Wnt5a-mediated augmentation in phagocytosis is suppressed by blocking expression of the putative Wnt5a receptor Frizzled 5. Enhanced phagocytosis of bacteria by Wnt5a-Fz5 signaling increases the secretion of proinflammatory cytokines, but not the bacterial killing rate. Furthermore, a small molecule inhibitor of Wnt production, IWP-2, which reduces secretion of functionally active Wnt5a, not only suppresses both phagocytosis and the secretion of proinflammatory cytokines but also accelerates the bacterial killing rate.
Collapse
|
28
|
Galindo RC, Ayllón N, Smrdel KS, Boadella M, Beltrán-Beck B, Mazariegos M, García N, de la Lastra JMP, Avsic-Zupanc T, Kocan KM, Gortazar C, de la Fuente J. Gene expression profile suggests that pigs (Sus scrofa) are susceptible to Anaplasma phagocytophilum but control infection. Parasit Vectors 2012; 5:181. [PMID: 22935149 PMCID: PMC3453518 DOI: 10.1186/1756-3305-5-181] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 08/12/2012] [Indexed: 11/26/2022] Open
Abstract
Background Anaplasma phagocytophilum infects a wide variety of hosts and causes granulocytic anaplasmosis in humans, horses and dogs and tick-borne fever in ruminants. Infection with A. phagocytophilum results in the modification of host gene expression and immune response. The objective of this research was to characterize gene expression in pigs (Sus scrofa) naturally and experimentally infected with A. phagocytophilum trying to identify mechanisms that help to explain low infection prevalence in this species. Results For gene expression analysis in naturally infected pigs, microarray hybridization was used. The expression of differentially expressed immune response genes was analyzed by real-time RT-PCR in naturally and experimentally infected pigs. Results suggested that A. phagocytophilum infection affected cytoskeleton rearrangement and increased both innate and adaptive immune responses by up regulation of interleukin 1 receptor accessory protein-like 1 (IL1RAPL1), T-cell receptor alpha chain (TCR-alpha), thrombospondin 4 (TSP-4) and Gap junction protein alpha 1 (GJA1) genes. Higher serum levels of IL-1 beta, IL-8 and TNF-alpha in infected pigs when compared to controls supported data obtained at the mRNA level. Conclusions These results suggested that pigs are susceptible to A. phagocytophilum but control infection, particularly through activation of innate immune responses, phagocytosis and autophagy. This fact may account for the low infection prevalence detected in pigs in some regions and thus their low or no impact as a reservoir host for this pathogen. These results advanced our understanding of the molecular mechanisms at the host-pathogen interface and suggested a role for newly reported genes in the protection of pigs against A. phagocytophilum.
Collapse
Affiliation(s)
- Ruth C Galindo
- Instituto de Investigación en Recursos Cinegéticos IREC-CSIC-UCLM-JCCM, Ronda de Toledo s/n, Ciudad Real 13005, Spain
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Connexins in atherosclerosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:157-66. [PMID: 22609170 DOI: 10.1016/j.bbamem.2012.05.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 04/26/2012] [Accepted: 05/04/2012] [Indexed: 11/20/2022]
Abstract
Atherosclerosis, a chronic inflammatory disease of the vessel wall, involves multiple cell types of different origins, and complex interactions and signaling pathways between them. Autocrine and paracrine communication pathways provided by cytokines, chemokines, growth factors and lipid mediators are central to atherogenesis. However, it is becoming increasingly recognized that a more direct communication through both hemichannels and gap junction channels formed by connexins also plays an important role in atherosclerosis development. Three main connexins are expressed in cells involved in atherosclerosis: Cx37, Cx40 and Cx43. Cx37 is found in endothelial cells, monocytes/macrophages and platelets, Cx40 is predominantly an endothelial connexin, and Cx43 is found in a large variety of cells such as smooth muscle cells, resident and circulating leukocytes (neutrophils, dendritic cells, lymphocytes, activated macrophages, mast cells) and some endothelial cells. Here, we will systematically review the expression and function of connexins in cells and processes underlying atherosclerosis. This article is part of a Special Issue entitled: The Communicating junctions, roles and dysfunctions.
Collapse
|
30
|
Parthasarathi K. Endothelial connexin43 mediates acid-induced increases in pulmonary microvascular permeability. Am J Physiol Lung Cell Mol Physiol 2012; 303:L33-42. [PMID: 22561459 DOI: 10.1152/ajplung.00219.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Acid aspiration, a common cause of acute lung injury, leads to alveolar edema. Increase in lung vascular permeability underlies this pathology. To define mechanisms, isolated rat lungs were perfused with autologous blood. Hydrochloric acid and rhodamine-dextran 70 kDa (RDx70) were coinstilled into an alveolus by micropuncture. RDx70 fluorescence was used to establish the spatial distribution of acid. Subsequently, FITC-dextran 20 kDa (FDx20) was infused into microvessels for 60 min followed by a 10-min HEPES-buffered saline wash. During the infusion, FITC fluorescence changes were recorded to quantify the ratio of peak to postwash fluorescence. The ratio, termed normalized fluorescence, was low for acid compared with buffer instillation both in microvessels abutting acid-treated alveoli and those located more than 700 μm away. In contrast, the normalized fluorescence was similar to buffer controls when a higher molecular weight tracer (FITC-dextran 70 kDa) was infused instead of FDx20, suggesting that normalized FDx20 fluorescence faithfully represented microvascular permeability. Inhibiting endothelial connexin43 (Cx43) gap junction communication with Gap27 blunted the acid-induced reduction in normalized fluorescence, although scrambled Gap27 did not have any effect. The blunting was evident not only in microvessels away from the site of injury, but also in those abutting directly injured alveoli. Thus the new fluorescence-based method reveals that acid increases microvascular permeability both at acid-instilled and away sites. Inhibiting endothelial Cx43 blocked the permeability increase even at the direct injury sites. These data indicate for the first time that Cx43-dependent mechanisms mediate acid-induced increases in microvascular permeability. Cx43 may be a therapeutic target in acid injury.
Collapse
|
31
|
Vishniakova KS, Kireev II, Dunina-Barkovskaya AY. Effects of cell culture density on phagocytosis parameters in IC-21 macrophages. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2011. [DOI: 10.1134/s1990747811050138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|