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Cardouat G, Douard M, Bouchet C, Roubenne L, Kmecová Z, Esteves P, Brette F, Guignabert C, Tu L, Campagnac M, Robillard P, Coste F, Delcambre F, Thumerel M, Begueret H, Maurac A, Belaroussi Y, Klimas J, Ducret T, Quignard JF, Vacher P, Baudrimont I, Marthan R, Berger P, Guibert C, Freund-Michel V. NGF increases Connexin-43 expression and function in pulmonary arterial smooth muscle cells to induce pulmonary artery hyperreactivity. Biomed Pharmacother 2024; 174:116552. [PMID: 38599061 DOI: 10.1016/j.biopha.2024.116552] [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: 11/26/2023] [Revised: 03/30/2024] [Accepted: 04/04/2024] [Indexed: 04/12/2024] Open
Abstract
AIMS Pulmonary hypertension (PH) is characterised by an increase in pulmonary arterial pressure, ultimately leading to right ventricular failure and death. We have previously shown that nerve growth factor (NGF) plays a critical role in PH. Our objectives here were to determine whether NGF controls Connexin-43 (Cx43) expression and function in the pulmonary arterial smooth muscle, and whether this mechanism contributes to NGF-induced pulmonary artery hyperreactivity. METHODS AND RESULTS NGF activates its TrkA receptor to increase Cx43 expression, phosphorylation, and localization at the plasma membrane in human pulmonary arterial smooth muscle cells, thus leading to enhanced activity of Cx43-dependent GAP junctions as shown by Lucifer Yellow dye assay transfer and fluorescence recovery after photobleaching -FRAP- experiments. Using both in vitro pharmacological and in vivo SiRNA approaches, we demonstrate that NGF-dependent increase in Cx43 expression and activity in the rat pulmonary circulation causes pulmonary artery hyperreactivity. We also show that, in a rat model of PH induced by chronic hypoxia, in vivo blockade of NGF or of its TrkA receptor significantly reduces Cx43 increased pulmonary arterial expression induced by chronic hypoxia and displays preventive effects on pulmonary arterial pressure increase and right heart hypertrophy. CONCLUSIONS Modulation of Cx43 by NGF in pulmonary arterial smooth muscle cells contributes to NGF-induced alterations of pulmonary artery reactivity. Since NGF and its TrkA receptor play a role in vivo in Cx43 increased expression in PH induced by chronic hypoxia, these NGF/Cx43-dependent mechanisms may therefore play a significant role in human PH pathophysiology.
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MESH Headings
- Animals
- Humans
- Male
- Rats
- Cells, Cultured
- Connexin 43/metabolism
- Gap Junctions/metabolism
- Gap Junctions/drug effects
- Hypertension, Pulmonary/metabolism
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/drug effects
- Nerve Growth Factor/metabolism
- Phosphorylation
- Pulmonary Artery/drug effects
- Pulmonary Artery/metabolism
- Pulmonary Artery/pathology
- Rats, Sprague-Dawley
- Rats, Wistar
- Receptor, trkA/metabolism
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Affiliation(s)
| | - Matthieu Douard
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France; Univ. Bordeaux, INSERM, CRCTB, U 1045, IHU Liryc, Bordeaux F-33000, France
| | - Clément Bouchet
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France
| | - Lukas Roubenne
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France
| | - Zuzana Kmecová
- Department of Pharmacology and Toxicology, Comenius University, Bratislava, Slovakia
| | - Pauline Esteves
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France
| | - Fabien Brette
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France; Univ. Bordeaux, INSERM, CRCTB, U 1045, IHU Liryc, Bordeaux F-33000, France
| | - Christophe Guignabert
- INSERM UMR_S 999, « Pulmonary Hypertension: Pathophysiology and Novel Therapies », Hôpital Marie Lannelongue, Le Plessis-Robinson 92350, France; Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre 94270, France
| | - Ly Tu
- INSERM UMR_S 999, « Pulmonary Hypertension: Pathophysiology and Novel Therapies », Hôpital Marie Lannelongue, Le Plessis-Robinson 92350, France; Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre 94270, France
| | | | - Paul Robillard
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France
| | - Florence Coste
- Laboratoire de Pharm-écologie Cardiovasculaire (LaPEC-EA 4278), Université d'Avignon et des Pays du Vaucluse, Avignon 84000, France
| | | | - Matthieu Thumerel
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France; CHU de Bordeaux, Bordeaux 33000, France
| | | | | | | | - Jan Klimas
- Department of Pharmacology and Toxicology, Comenius University, Bratislava, Slovakia
| | - Thomas Ducret
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France
| | | | - Pierre Vacher
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France
| | | | - Roger Marthan
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France; CHU de Bordeaux, Bordeaux 33000, France
| | - Patrick Berger
- Univ. Bordeaux, INSERM, CRCTB, U 1045, Bordeaux F-33000, France; CHU de Bordeaux, Bordeaux 33000, France
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Xu S, Wei J, Liu Y, Zhang L, Duan M, Li J, Niu Z, Pu X, Huang M, Chen H, Zhou X, Xie J. PDGF-AA guides cell crosstalk between human dental pulp stem cells in vitro via the PDGFR-α/PI3K/Akt axis. Int Endod J 2024; 57:549-565. [PMID: 38332717 DOI: 10.1111/iej.14038] [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: 09/26/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024]
Abstract
AIM To explore the influence of PDGF-AA on cell communication between human dental pulp stem cells (DPSCs) by characterizing gap junction intercellular communication (GJIC) and its potential biomechanical mechanism. METHODOLOGY Quantitative real-time PCR was used to measure connexin family member expression in DPSCs. Cell migration and CCK-8 assays were utilized to examine the influence of PDGF-AA on DPSC migration and proliferation. A scrape loading/dye transfer assay was applied to evaluate GJIC triggered by PDGF-AA, a PI3K/Akt signalling pathway blocker (LY294002) and a PDGFR-α blocker (AG1296). Western blotting and immunofluorescence were used to test the expression and distribution of the Cx43 and p-Akt proteins in DPSCs. Scanning electron microscopy (SEM) and immunofluorescence were used to observe the morphology of GJIC in DPSCs. RESULTS PDGF-AA promoted gap junction formation and intercellular communication between human dental pulp stem cells. PDGF-AA upregulates the expression of Cx43 to enhance gap junction formation and intercellular communication. PDGF-AA binds to PDGFR-α and activates PI3K/Akt signalling to regulate cell communication. CONCLUSIONS This research demonstrated that PDGF-AA can enhance Cx43-mediated GJIC in DPSCs via the PDGFR-α/PI3K/Akt axis, which provides new cues for dental pulp regeneration from the perspective of intercellular communication.
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Affiliation(s)
- Siqun Xu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Jieya Wei
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Li Zhang
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Mengmeng Duan
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Jiazhou Li
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Zhixing Niu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xiaohua Pu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Minglei Huang
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Hao Chen
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Shuyuan L, Haoyu C. Mechanism of Nardostachyos Radix et Rhizoma-Salidroside in the treatment of premature ventricular beats based on network pharmacology and molecular docking. Sci Rep 2023; 13:20741. [PMID: 38007574 PMCID: PMC10676380 DOI: 10.1038/s41598-023-48277-0] [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: 09/12/2023] [Accepted: 11/24/2023] [Indexed: 11/27/2023] Open
Abstract
To analyse the mechanism of Nardostachyos Radix et Rhizoma-Salidroside in the treatment of Premature Ventricular Brats by using network pharmacology and molecular docking and to provide the basis for developing the use of experimental and clinical traditional Chinese medicine. The chemical compositions of Nardostachyos Radix et Rhizoma and Salidroside were determined, and their related targets were predicted. The disease-related targets were obtained by searching the common disease databases Genecards, OMIM, Drugbank and DisGeNET, and the intersection between the predicted targets and the disease targets was determined. Then using the STRING database to set up the protein‒protein interactions (PPIs) network between Nardostachyos Radix et Rhizoma-Salidroside and the common targets of PVB. An "herb-ingredient-target" network was constructed and analyzed by Cytoscape3.7.2 software. Using the metascape database to analysis the predicted therapeutic targets based on the GO and KEGG. Finally, molecular docking technology was used toconfirm the capacity of the primary active ingredients of the 2 herbs to bind to central targets using the online CB-Dock2 database. 41 active components of Nardostachyos Radix et Rhizoma-Salidroside were detected, with 420 potential targets of action, with a total of 1688 PVB targets, and the top 10 core targets of herb-disease degree values were AKT1, TNF, GAPDH, SRC, PPARG, EGFR, PTGS2, ESR1, MMP9, and STAT3. KEGG analysis indicated that its mechanism may be related to the calcium signalling pathway, cancer signalling pathway, AGE-RAGE signalling pathway and other pathways. Molecular docking suggested that main of the active ingredients of the Nardostachyos Radix et Rhizoma-Salidroside pairs were well bound to the core targets. Based on novel network pharmacology and molecular docking validation research methods, we revealed for the first time the potential mechanism of Nardostachyos Radix et Rhizoma-Salidroside in PVB therapy.
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Affiliation(s)
- Liu Shuyuan
- The First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, ShanDong, People's Republic of China, 250013
| | - Chen Haoyu
- Cardiology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, ShanDong, People's Republic of China, 250011.
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Zhang M, Wang ZZ, Chen NH. Connexin 43 Phosphorylation: Implications in Multiple Diseases. Molecules 2023; 28:4914. [PMID: 37446576 DOI: 10.3390/molecules28134914] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Connexin 43 (Cx43) is most widely distributed in mammals, especially in the cardiovascular and nervous systems. Its phosphorylation state has been found to be regulated by the action of more than ten kinases and phosphatases, including mitogen-activated protein kinase/extracellular signaling and regulating kinase signaling. In addition, the phosphorylation status of different phosphorylation sites affects its own synthesis and assembly and the function of the gap junctions (GJs) to varying degrees. The phosphorylation of Cx43 can affect the permeability, electrical conductivity, and gating properties of GJs, thereby having various effects on intercellular communication and affecting physiological or pathological processes in vitro and in vivo. Therefore, clarifying the relationship between Cx43 phosphorylation and specific disease processes will help us better understand the disease. Based on the above clinical and preclinical findings, we present in this review the functional significance of Cx43 phosphorylation in multiple diseases and discuss the potential of Cx43 as a drug target in Cx43-related disease pathophysiology, with an emphasis on the importance of connexin 43 as an emerging therapeutic target in cardiac and neuroprotection.
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Affiliation(s)
- Meng Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
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Zhao D, Wu J, Acosta FM, Xu H, Jiang JX. Connexin 43 hemichannels and prostaglandin E 2 release in anabolic function of the skeletal tissue to mechanical stimulation. Front Cell Dev Biol 2023; 11:1151838. [PMID: 37123401 PMCID: PMC10133519 DOI: 10.3389/fcell.2023.1151838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/05/2023] [Indexed: 05/02/2023] Open
Abstract
Bone adapts to changes in the physical environment by modulating remodeling through bone resorption and formation to maintain optimal bone mass. As the most abundant connexin subtype in bone tissue, connexin 43 (Cx43)-forming hemichannels are highly responsive to mechanical stimulation by permitting the exchange of small molecules (<1.2 kDa) between bone cells and the extracellular environment. Upon mechanical stimulation, Cx43 hemichannels facilitate the release of prostaglandins E2 (PGE2), a vital bone anabolic factor from osteocytes. Although most bone cells are involved in mechanosensing, osteocytes are the principal mechanosensitive cells, and PGE2 biosynthesis is greatly enhanced by mechanical stimulation. Mechanical stimulation-induced PGE2 released from osteocytic Cx43 hemichannels acts as autocrine effects that promote β-catenin nuclear accumulation, Cx43 expression, gap junction function, and protects osteocytes against glucocorticoid-induced osteoporosis in cultured osteocytes. In vivo, Cx43 hemichannels with PGE2 release promote bone formation and anabolism in response to mechanical loading. This review summarizes current in vitro and in vivo understanding of Cx43 hemichannels and extracellular PGE2 release, and their roles in bone function and mechanical responses. Cx43 hemichannels could be a significant potential new therapeutic target for treating bone loss and osteoporosis.
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Affiliation(s)
- Dezhi Zhao
- School of Medicine, Northwest University, Xi’an, China
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Jiawei Wu
- School of Medicine, Northwest University, Xi’an, China
| | - Francisca M. Acosta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Huiyun Xu
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
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Zhao GL, Zhou H, Guo YH, Zhong SM, Zhou H, Li F, Lei B, Wang Z, Miao Y. Modulation of Rac1/PAK1/connexin43-mediated ATP release from astrocytes contributes to retinal ganglion cell survival in experimental glaucoma. Glia 2023; 71:1502-1521. [PMID: 36794533 DOI: 10.1002/glia.24354] [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: 07/01/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/17/2023]
Abstract
Connexin43 (Cx43) is a major gap junction protein in glial cells. Mutations have been found in the gap-junction alpha 1 gene encoding Cx43 in glaucomatous human retinas, suggestive of the involvement of Cx43 in the pathogenesis of glaucoma. However, how Cx43 is involved in glaucoma is still unknown. We showed that increased intraocular pressure in a glaucoma mouse model of chronic ocular hypertension (COH) downregulated Cx43, which was mainly expressed in retinal astrocytes. Astrocytes in the optic nerve head where they gather and wrap the axons (optic nerve) of retinal ganglion cells (RGCs) were activated earlier than neurons in COH retinas and the alterations in astrocytes plasticity in the optic nerve caused a reduction in Cx43 expression. A time course showed that reductions of Cx43 expression were correlated with the activation of Rac1, a member of the Rho family. Co-immunoprecipitation assays showed that active Rac1, or the downstream signaling effector PAK1, negatively regulated Cx43 expression, Cx43 hemichannel opening and astrocyte activation. Pharmacological inhibition of Rac1 stimulated Cx43 hemichannel opening and ATP release, and astrocytes were identified to be one of the main sources of ATP. Furthermore, conditional knockout of Rac1 in astrocytes enhanced Cx43 expression and ATP release, and promoted RGC survival by upregulating the adenosine A3 receptor in RGCs. Our study provides new insight into the relationship between Cx43 and glaucoma, and suggests that regulating the interaction between astrocytes and RGCs via the Rac1/PAK1/Cx43/ATP pathway may be used as part of a therapeutic strategy for managing glaucoma.
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Affiliation(s)
- Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Hong Zhou
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yun-Hui Guo
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Shu-Min Zhong
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Han Zhou
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Fang Li
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Bo Lei
- Institute of Neuroscience and Third Affiliated Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Zhongfeng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yanying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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Pérez-Núñez R, Chamorro A, González MF, Contreras P, Artigas R, Corvalán AH, van Zundert B, Reyes C, Moya PR, Avalos AM, Schneider P, Quest AFG, Leyton L. Protein kinase B (AKT) upregulation and Thy-1-α vβ 3 integrin-induced phosphorylation of Connexin43 by activated AKT in astrogliosis. J Neuroinflammation 2023; 20:5. [PMID: 36609298 PMCID: PMC9817390 DOI: 10.1186/s12974-022-02677-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 12/18/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND In response to brain injury or inflammation, astrocytes undergo hypertrophy, proliferate, and migrate to the damaged zone. These changes, collectively known as "astrogliosis", initially protect the brain; however, astrogliosis can also cause neuronal dysfunction. Additionally, these astrocytes undergo intracellular changes involving alterations in the expression and localization of many proteins, including αvβ3 integrin. Our previous reports indicate that Thy-1, a neuronal glycoprotein, binds to this integrin inducing Connexin43 (Cx43) hemichannel (HC) opening, ATP release, and astrocyte migration. Despite such insight, important links and molecular events leading to astrogliosis remain to be defined. METHODS Using bioinformatics approaches, we analyzed different Gene Expression Omnibus datasets to identify changes occurring in reactive astrocytes as compared to astrocytes from the normal mouse brain. In silico analysis was validated by both qRT-PCR and immunoblotting using reactive astrocyte cultures from the normal rat brain treated with TNF and from the brain of a hSOD1G93A transgenic mouse model. We evaluated the phosphorylation of Cx43 serine residue 373 (S373) by AKT and ATP release as a functional assay for HC opening. In vivo experiments were also performed with an AKT inhibitor (AKTi). RESULTS The bioinformatics analysis revealed that genes of the PI3K/AKT signaling pathway were among the most significantly altered in reactive astrocytes. mRNA and protein levels of PI3K, AKT, as well as Cx43, were elevated in reactive astrocytes from normal rats and from hSOD1G93A transgenic mice, as compared to controls. In vitro, reactive astrocytes stimulated with Thy-1 responded by activating AKT, which phosphorylated S373Cx43. Increased pS373Cx43 augmented the release of ATP to the extracellular medium and AKTi inhibited these Thy-1-induced responses. Furthermore, in an in vivo model of inflammation (brain damage), AKTi decreased the levels of astrocyte reactivity markers and S373Cx43 phosphorylation. CONCLUSIONS Here, we identify changes in the PI3K/AKT molecular signaling network and show how they participate in astrogliosis by regulating the HC protein Cx43. Moreover, because HC opening and ATP release are important in astrocyte reactivity, the phosphorylation of Cx43 by AKT and the associated increase in ATP release identify a potential therapeutic window of opportunity to limit the adverse effects of astrogliosis.
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Affiliation(s)
- Ramón Pérez-Núñez
- grid.443909.30000 0004 0385 4466Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile ,grid.443909.30000 0004 0385 4466Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Alejandro Chamorro
- grid.443909.30000 0004 0385 4466Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile ,grid.443909.30000 0004 0385 4466Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - María Fernanda González
- grid.443909.30000 0004 0385 4466Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile ,grid.443909.30000 0004 0385 4466Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Pamela Contreras
- grid.443909.30000 0004 0385 4466Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile ,grid.443909.30000 0004 0385 4466Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Rocío Artigas
- grid.7870.80000 0001 2157 0406Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Pontificia Universidad Católica de Chile (PUC), 833-1150 Santiago, Chile
| | - Alejandro H. Corvalán
- grid.7870.80000 0001 2157 0406Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Pontificia Universidad Católica de Chile (PUC), 833-1150 Santiago, Chile ,grid.7870.80000 0001 2157 0406Department of Hematology and Oncology, Facultad de Medicina, Pontificia Universidad Católica de Chile (PUC), 833-1150 Santiago, Chile
| | - Brigitte van Zundert
- grid.412848.30000 0001 2156 804XInstitute of Biomedical Sciences (ICB), Faculty of Medicine & Faculty of Life Sciences, Universidad Andres Bello, 837-0186 Santiago, Chile ,grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655 USA
| | - Christopher Reyes
- grid.412185.b0000 0000 8912 4050Instituto de Fisiología, Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Pablo R. Moya
- grid.412185.b0000 0000 8912 4050Instituto de Fisiología, Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ana María Avalos
- grid.441837.d0000 0001 0765 9762Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Pascal Schneider
- grid.9851.50000 0001 2165 4204Department of Biochemistry, University of Lausanne, 1066 Epalinges, Switzerland
| | - Andrew F. G. Quest
- grid.443909.30000 0004 0385 4466Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile ,grid.443909.30000 0004 0385 4466Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
| | - Lisette Leyton
- grid.443909.30000 0004 0385 4466Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile ,grid.443909.30000 0004 0385 4466Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453 Santiago, Chile
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Zeng Y, Riquelme MA, Hua R, Zhang J, Acosta FM, Gu S, Jiang JX. Mechanosensitive piezo1 calcium channel activates connexin 43 hemichannels through PI3K signaling pathway in bone. Cell Biosci 2022; 12:191. [PMID: 36457052 PMCID: PMC9716748 DOI: 10.1186/s13578-022-00929-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/11/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Mechanical loading promotes bone formation and osteocytes are a major mechanosensory cell in the bone. Both Piezo1 channels and connexin 43 hemichannels (Cx43 HCs) in osteocytes are important players in mechanotransduction and anabolic function by mechanical loading. However, the mechanism underlying mechanotransduction involving Piezo1 channels and Cx43 HCs in osteocytes and bone remains unknown. RESULTS We showed that, like mechanical loading, Piezo1 specific agonist Yoda1 was able to increase intracellular Ca2+ signaling and activate Cx43 HCs, while Yoda1 antagonist Dooku1 inhibited Ca2+ and Cx43 HC activation induced by both mechanical loading and Yoda1. Moreover, the intracellular Ca2+ signal activated by Yoda1 was reduced by the inhibition of Cx43 HCs and pannexin1 (Panx1) channels, as well as ATP-P2X receptor signaling. Piezo1 and Cx43 HCs were co-localized on the osteocyte cell surface, and Yoda1-activated PI3K-Akt signaling regulated the opening of Cx43 HCs. Furthermore, Cx43 HCs opening by mechanical loading on tibias was ablated by inhibition of Piezo1 activation in vivo. CONCLUSION We demonstrated that upon mechanical stress, increased intracellular Ca2+ activated by Piezo1 regulates the opening of HCs through PI3K-Akt and opened Cx43 HCs, along with Panx1 channels, and ATP-P2X signaling sustain the intracellular Ca2+ signal, leading to bone anabolic function.
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Affiliation(s)
- Yan Zeng
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA ,grid.452708.c0000 0004 1803 0208The Second Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Manuel A. Riquelme
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Rui Hua
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Jingruo Zhang
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Francisca M. Acosta
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Sumin Gu
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
| | - Jean X. Jiang
- grid.267309.90000 0001 0629 5880Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX USA
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9
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Xu S, Liu Y, Zhang D, Huang H, Li J, Wei J, Yang Y, Cui Y, Xie J, Zhou X. PDGF-AA promotes gap junction intercellular communication in chondrocytes via the PI3K/Akt pathway. Connect Tissue Res 2022; 63:544-558. [PMID: 35152816 DOI: 10.1080/03008207.2022.2036733] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Gap junction intercellular communication (GJIC) plays an important role in cell growth, development and homeostasis. Connexin 43 (Cx43) is an important half-channel protein responsible for gap junction formation. Platelet-derived growth factor AA (PDGF-AA) regulates the proliferation, migration, metabolism, apoptosis and cell cycle of chondrocytes. However, the role of PDGF-AA in gap junction intercellular communication in chondrocytes is not fully understood. In the current study, we performed experiments to explore the effect of PDGF-AA on GJIC and its underlying biomechanical mechanism. METHODS qPCR was performed to determine the expression of PDGF, PDGFR and connexin family genes in chondrocytes and/or cartilage. A scrape loading/dye transfer assay was used to determine GJIC. Western blot analysis was applied to detect the expression of Cx43 and PI3K/Akt signaling pathway proteins. Immunofluorescence staining was utilized to examine protein distribution. Scanning electron microscopy was used to delineate the morphology of chondrocytes. RESULTS Expression of PDGF-A mRNA was highest among the PDGF family in chondrocytes and cartilage tissues. PDGF-AA promoted functional GJIC formation in chondrocytes by upregulating the expression of Cx43. Enhanced functional GJIC formation in chondrocytes induced by PDGF-AA occurred through the activation of PI3K/Akt signaling and its nuclear accumulation. CONCLUSION For the first time, this study provides evidence demonstrating the role of PDGF-AA in cell-to-cell communication in chondrocytes through mediating Cx43 expression.
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Affiliation(s)
- Siqun Xu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Demao Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hongcan Huang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiachi Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jieya Wei
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yueyi Yang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yujia Cui
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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10
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Zhao D, Hua R, Riquelme MA, Cheng H, Guda T, Xu H, Gu S, Jiang JX. Osteocytes regulate bone anabolic response to mechanical loading in male mice via activation of integrin α5. Bone Res 2022; 10:49. [PMID: 35851577 PMCID: PMC9293884 DOI: 10.1038/s41413-022-00222-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 05/25/2022] [Accepted: 06/13/2022] [Indexed: 12/18/2022] Open
Abstract
Physical mechanical stimulation can maintain and even increase bone mass. Here, we report an important role of osteocytic integrin α5 in regulating the anabolic response of bone to mechanical loading using an Itga5 conditional gene knockout (cKO) mouse model. Integrin α5 gene deletion increased apoptotic osteocytes and reduced cortical anabolic responses to tibial compression including decreased endosteal osteoblasts and bone formation, and increased endosteal osteoclasts and bone resorption, contributing to the decreased bone area fraction and biomechanical properties, leading to an enlarged bone marrow area in cKO mice. Similar disruption of anabolic responses to mechanical loading was also detected in cKO trabecular bone. Moreover, integrin α5 deficiency impeded load-induced Cx43 hemichannel opening, and production and release of PGE2, an anabolic factor, resulting in attenuated effects of the loading on catabolic sclerostin (SOST) reduction and anabolic β-catenin increase. Together, this study shows an indispensable role of integrin α5 in osteocytes in the anabolic action of mechanical loading on skeletal tissue through activation of hemichannels and PGE2-evoked gene expression. Integrin α5 could act as a potential new therapeutic target for bone loss, especially in the elderly population with impeded mechanical sensitivity.
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Affiliation(s)
- Dezhi Zhao
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Rui Hua
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Hongyun Cheng
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Teja Guda
- Department of Biomedical Engineering and Chemical Engineering, University of Texas, San Antonio, TX, USA
| | - Huiyun Xu
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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11
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Shen Y, Jing D, Zhao Z. The effect of AKT in extracellular matrix stiffness induced osteogenic differentiation of hBMSCs. Cell Signal 2022; 99:110404. [PMID: 35835331 DOI: 10.1016/j.cellsig.2022.110404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/02/2022] [Accepted: 07/08/2022] [Indexed: 02/05/2023]
Abstract
Extracellular matrix (ECM) stiffness is an important biophysical factor in human bone marrow mesenchymal stem cells (hBMSCs) differentiation. Although there is evidence that Yes-associated protein (YAP) plays an important role in ECM elasticity induced osteogenesis, but the regulatory mechanism and signaling pathways have not been distinctly uncovered. In this study, hBMSCs were cultured on collagen-coated polydimethylsiloxane hydrogels with stiffness corresponding to Young's moduli of 0.5 kPa and 32 kPa, and gene chip analyses revealed the phosphoinositide 3-kinase (PI3K)-AKT pathway was highly correlated with ECM stiffness. Following western blots indicated that AKT phosphorylation was evidently affected in 5th-7th days after ECM stiffness stimulation, while PI3K showed little difference. The AKT activator SC79 and inhibitor MK2206 were utilized to modulate AKT phosphorylation. SC79 and MK2206 caused alteration in the mRNA expression and protein level of alkaline phosphatase (ALP), collagen type I alpha 1 (COL1A1) and runt related transcription factor 2 (RUNX2). On 32 kPa substrates, YAP enrichment in nucleus were significantly promoted by SC79 and remarkably decreased by MK2206. Besides, the ratio of YAP/p-YAP is upregulated by SC79 on both 32 kPa and 0.5 kPa substrates. In conclusion, these findings suggest that AKT is involved in the modulation of ECM stiffness induced osteogenesis, and AKT phosphorylation also influences the subcellular localization and activation of YAP.
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Affiliation(s)
- Yu Shen
- School of Basic Medical Sciences, Chengdu University, Chengdu 610106, China
| | - Dian Jing
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, China.
| | - Zhihe Zhao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
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12
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Zhao D, Riquelme MA, Guda T, Tu C, Xu H, Gu S, Jiang JX. Connexin hemichannels with prostaglandin release in anabolic function of bone to mechanical loading. eLife 2022; 11:74365. [PMID: 35132953 PMCID: PMC8824479 DOI: 10.7554/elife.74365] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/10/2022] [Indexed: 01/18/2023] Open
Abstract
Mechanical stimulation, such as physical exercise, is essential for bone formation and health. Here, we demonstrate the critical role of osteocytic Cx43 hemichannels in anabolic function of bone in response to mechanical loading. Two transgenic mouse models, R76W and Δ130–136, expressing dominant-negative Cx43 mutants in osteocytes were adopted. Mechanical loading of tibial bone increased cortical bone mass and mechanical properties in wild-type and gap junction-impaired R76W mice through increased PGE2, endosteal osteoblast activity, and decreased sclerostin. These anabolic responses were impeded in gap junction/hemichannel-impaired Δ130–136 mice and accompanied by increased endosteal osteoclast activity. Specific inhibition of Cx43 hemichannels by Cx43(M1) antibody suppressed PGE2 secretion and impeded loading-induced endosteal osteoblast activity, bone formation and anabolic gene expression. PGE2 administration rescued the osteogenic response to mechanical loading impeded by impaired hemichannels. Together, osteocytic Cx43 hemichannels could be a potential new therapeutic target for treating bone loss and osteoporosis.
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Affiliation(s)
- Dezhi Zhao
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, United States.,School of Life Sciences, Northwestern Polytechnical University, Xian, China
| | - Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, United States
| | - Teja Guda
- Department of Biomedical Engineering and Chemical Engineering, University of Texas at San Antonio, San Antonio, United States
| | - Chao Tu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, United States.,Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Huiyun Xu
- School of Life Sciences, Northwestern Polytechnical University, Xian, China
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, United States
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, United States
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13
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An S, Zheng S, Cai Z, Chen S, Wang C, Li Y, Deng Z. Connexin43 in Musculoskeletal System: New Targets for Development and Disease Progression. Aging Dis 2022; 13:1715-1732. [DOI: 10.14336/ad.2022.0421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
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14
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Liu Y, Duan M, Guo D, Kan S, Zhang L, Aili M, Zhang D, Du W, Xie J. PDGF-AA promotes cell-to-cell communication in osteocytes through PI3K/Akt signaling pathway. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1640-1649. [PMID: 34586354 DOI: 10.1093/abbs/gmab136] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/24/2021] [Accepted: 09/23/2021] [Indexed: 02/05/2023] Open
Abstract
Osteocytes are the main sensitive cells in bone remodeling due to their potent functional cell processes from the mineralized bone matrix to the bone surface and the bone marrow. Neighboring osteocytes communicate with each other by these cell processes to achieve molecular exchange through gap junction channels. Platelet-derived growth factor-AA (PDGF-AA) has been reported to enhance bone tissue remodeling by promoting cell proliferation, migration, and autocrine secretion in osteoid cell linage. However, the effect of PDGF-AA on intercellular communication between osteocytes is still unclear. In the present study, we elucidated that PDGF-AA could enhance the formation of dendritic processes of osteocytes and the gap junctional intercellular communication by promoting the expression of connexin43 (Cx43). This modulation process was mainly dependent on the activation of phosphorylation of Akt protein by phosphatidylinositol 3-kinase (PI3K)/Akt (also known as protein kinase B, PKB) signaling. Inhibition of PI3K/Akt signaling decreased the Cx43 expression induced by PDGF-AA. These results establish a bridge between PDGF-AA and cell-cell communication in osteocytes, which could help us understand the molecular exchange between bone cells and fracture healing.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Mengmeng Duan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Daimo Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Shiyi Kan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Li Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Munire Aili
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Demao Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Wei Du
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
- Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610064, China
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15
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Lewis KJ. Osteocyte calcium signaling - A potential translator of mechanical load to mechanobiology. Bone 2021; 153:116136. [PMID: 34339908 DOI: 10.1016/j.bone.2021.116136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/25/2021] [Accepted: 07/27/2021] [Indexed: 10/20/2022]
Abstract
Osteocytes are embedded dendritic bone cells; by virtue of their position in bone tissue, ability to coordinate bone building osteoblasts and resorbing osteoclasts, and sensitivity to tissue level mechanical loading, they serve as the resident bone mechanosensor. The mechanisms osteocytes use to change mechanical loading into biological signals that drive tissue level changes has been well studied over the last 30 years, however the ways loading parameters are encoded at the cellular level are still not fully understood. Calcium signaling is a first messenger signal exhibited by osteocytes in response to mechanical forces. A body of work interrogating the mechanisms of osteocyte calcium signaling exists and is presently expanding, presenting the opportunity to better understand the relationship between calcium signaling characteristics and tuned osteocyte responses to tissue level strain features (e.g. magnitude, duration, frequency). This review covers the history of osteocyte load induced calcium signaling and highlights potential cellular mechanisms used by osteocytes to turn details about loading parameters into biological events.
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Affiliation(s)
- Karl J Lewis
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America.
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16
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Ai X, Yan J, Pogwizd SM. Serine-threonine protein phosphatase regulation of Cx43 dephosphorylation in arrhythmogenic disorders. Cell Signal 2021; 86:110070. [PMID: 34217833 PMCID: PMC8963383 DOI: 10.1016/j.cellsig.2021.110070] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/11/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022]
Abstract
Regulation of cell-to-cell communication in the heart by the gap junction protein Connexin43 (Cx43) involves modulation of Cx43 phosphorylation state by protein kinases, and dephosphorylation by protein phosphatases. Dephosphorylation of Cx43 has been associated with impaired intercellular coupling and enhanced arrhythmogenesis in various pathologic states. While there has been extensive study of the protein kinases acting on Cx43, there has been limited studies of the protein phosphatases that may underlie Cx43 dephosphorylation. The focus of this review is to introduce serine-threonine protein phosphatase regulation of Cx43 phosphorylation state and cell-to-cell communication, and its impact on arrhythmogenesis in the setting of chronic heart failure and myocardial ischemia, as well as on atrial fibrillation. We also discuss the therapeutic potential of modulating protein phosphatases to treat arrhythmias in these clinical settings.
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Affiliation(s)
- Xun Ai
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Jiajie Yan
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Steven M Pogwizd
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America.
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17
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Wu DP, Zhou Y, Hou LX, Zhu XX, Yi W, Yang SM, Lin TY, Huang JL, Zhang B, Yin XX. Cx43 deficiency confers EMT-mediated tamoxifen resistance to breast cancer via c-Src/PI3K/Akt pathway. Int J Biol Sci 2021; 17:2380-2398. [PMID: 34326682 PMCID: PMC8315014 DOI: 10.7150/ijbs.55453] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/30/2021] [Indexed: 12/25/2022] Open
Abstract
Tamoxifen (TAM) resistance has indicated a significant challenge during endocrine therapy for hormone-sensitive breast cancer. Thus, it is significant to elucidate the molecular events endowing TAM resistance to endocrine therapy. In this study, we found that epithelial-mesenchymal transition (EMT) was an important event to confer TAM resistance, and attenuating EMT by elevating connexin (Cx) 43 expression could reverse TAM resistance. Specifically, Cx43 overexpression improved TAM sensitivity, while Cx43 depletion facilitated TAM insensitivity by modulating EMT in T47D TAM-resistant and -sensitive cells, and transplanted xenografts. Importantly, we found a novel reciprocal regulation between Cx43 and c-Src/PI3K/Akt pathway contributing to EMT and TAM resistance in breast cancer. Moreover, we identified that Cx43 deficiency was significantly correlated with poor relapse-free survival in patients undergoing TAM treatment. Therefore, Cx43 represents a prognostic marker and an attractive target for breast cancer treatments. Therapeutic strategies designed to increase or maintain Cx43 function may be beneficial to overcome TAM resistance.
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Affiliation(s)
- Deng-Pan Wu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
- Department of Pharmacology, Pharmacy School of Xuzhou Medical University, 221004, Xuzhou City, Jiangsu Province, P.R. China
| | - Yan Zhou
- Clinical Pharmacy, Jingjiang People's Hospital, 214500, Jingjiang City, Jiangsu Province, P.R. China
| | - Li-Xiang Hou
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
| | - Xiao-Xiao Zhu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
| | - Wen Yi
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
| | - Si-Man Yang
- Scientific research center of traditional Chinese medicine, Guangxi University of Chinese Medicine, Nanning City, Guangxi Zhuang Autonomous Region, P.R. China
| | - Tian-Yu Lin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
| | - Jin-Lan Huang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
- Department of Pharmacology, Pharmacy School of Xuzhou Medical University, 221004, Xuzhou City, Jiangsu Province, P.R. China
| | - Bei Zhang
- Department of gynaecology and obstetrics, Xuzhou Central Hospital, 221009, Xuzhou City, Jiangsu Province, P.R. China
| | - Xiao-Xing Yin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou City, Jiangsu Province, 221004, P.R. China
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18
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Okamoto T, Park EJ, Kawamoto E, Usuda H, Wada K, Taguchi A, Shimaoka M. Endothelial connexin-integrin crosstalk in vascular inflammation. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166168. [PMID: 33991620 DOI: 10.1016/j.bbadis.2021.166168] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/18/2021] [Accepted: 05/02/2021] [Indexed: 02/06/2023]
Abstract
Cardiovascular diseases including blood vessel disorders represent a major cause of death globally. The essential roles played by local and systemic vascular inflammation in the pathogenesis of cardiovascular diseases have been increasingly recognized. Vascular inflammation triggers the aberrant activation of endothelial cells, which leads to the functional and structural abnormalities in vascular vessels. In addition to humoral mediators such as pro-inflammatory cytokines and prostaglandins, the alteration of physical and mechanical microenvironment - including vascular stiffness and shear stress - modify the gene expression profiles and metabolic profiles of endothelial cells via mechano-transduction pathways, thereby contributing to the pathogenesis of vessel disorders. Notably, connexins and integrins crosstalk each other in response to the mechanical stress, and, thereby, play an important role in regulating the mechano-transduction of endothelial cells. Here, we provide an overview on how the inter-play between connexins and integrins in endothelial cells unfold during the mechano-transduction in vascular inflammation.
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Affiliation(s)
- Takayuki Okamoto
- Department of Pharmacology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-city, Shimane 693-8501, Japan.
| | - Eun Jeong Park
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu-city, Mie 514-8507, Japan
| | - Eiji Kawamoto
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu-city, Mie 514-8507, Japan; Department of Emergency and Disaster Medicine, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu-city, Mie 514-8507, Japan
| | - Haruki Usuda
- Department of Pharmacology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-city, Shimane 693-8501, Japan
| | - Koichiro Wada
- Department of Pharmacology, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-city, Shimane 693-8501, Japan
| | - Akihiko Taguchi
- Department of Regenerative Medicine Research, Foundation for Biomedical Research and Innovation at Kobe, 2-2 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Motomu Shimaoka
- Department of Molecular Pathobiology and Cell Adhesion Biology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu-city, Mie 514-8507, Japan.
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19
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Camal Ruggieri IN, Cícero AM, Issa JPM, Feldman S. Bone fracture healing: perspectives according to molecular basis. J Bone Miner Metab 2021; 39:311-331. [PMID: 33151416 DOI: 10.1007/s00774-020-01168-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Abstract
Fractures have a great impact on health all around the world and with fracture healing optimization; this problem could be resolved partially. To make a practical contribution to this issue, the knowledge of bone tissue, cellularity, and metabolism is essential, especially cytoskeletal architecture and its transformations according to external pressures. Special physical and chemical characteristics of the extracellular matrix (ECM) allow the transmission of mechanical stimuli from outside the cell to the plasmatic membrane. The osteocyte cytoskeleton is conformed by a complex network of actin and microtubules combined with crosslinker proteins like vinculin and fimbrin, connecting and transmitting outside stimuli through EMC to cytoplasm. Herein, critical signaling pathways like Cx43-depending ones, MAPK/ERK, Wnt, YAP/TAZ, Rho-ROCK, and others are activated due to mechanical stimuli, resulting in osteocyte cytoskeletal changes and ECM remodeling, altering the tissue and, therefore, the bone. In recent years, the osteocyte has gained more interest and value in relation to bone homeostasis as a great coordinator of other cell populations, thanks to its unique functions. By integrating the latest advances in relation to intracellular signaling pathways, mechanotransmission system of the osteocyte and bone tissue engineering, there are promising experimental strategies, while some are ready for clinical trials. This work aims to show clearly and precisely the integration between cytoskeleton and main molecular pathways in relation to mechanotransmission mechanism in osteocytes, and the use of this theoretical knowledge in therapeutic tools for bone fracture healing.
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Affiliation(s)
- Iván Nadir Camal Ruggieri
- School of Medicine, LABOATEM (Osteoarticular Biology, Tissue Engineering and Emerging Therapies Laboratory), Biological Chemistry Cat, School of Medicine, Rosario National University, Rosario, Argentina.
| | - Andrés Mauricio Cícero
- School of Medicine, LABOATEM (Osteoarticular Biology, Tissue Engineering and Emerging Therapies Laboratory), Biological Chemistry Cat, School of Medicine, Rosario National University, Rosario, Argentina
| | | | - Sara Feldman
- School of Medicine, LABOATEM (Osteoarticular Biology, Tissue Engineering and Emerging Therapies Laboratory), Biological Chemistry Cat, School of Medicine, Rosario National University, Rosario, Argentina
- Research Council of the Rosario National University (CIUNR) and CONICET, Rosario, Argentina
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20
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Connexins in the Heart: Regulation, Function and Involvement in Cardiac Disease. Int J Mol Sci 2021; 22:ijms22094413. [PMID: 33922534 PMCID: PMC8122935 DOI: 10.3390/ijms22094413] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/20/2021] [Indexed: 12/20/2022] Open
Abstract
Connexins are a family of transmembrane proteins that play a key role in cardiac physiology. Gap junctional channels put into contact the cytoplasms of connected cardiomyocytes, allowing the existence of electrical coupling. However, in addition to this fundamental role, connexins are also involved in cardiomyocyte death and survival. Thus, chemical coupling through gap junctions plays a key role in the spreading of injury between connected cells. Moreover, in addition to their involvement in cell-to-cell communication, mounting evidence indicates that connexins have additional gap junction-independent functions. Opening of unopposed hemichannels, located at the lateral surface of cardiomyocytes, may compromise cell homeostasis and may be involved in ischemia/reperfusion injury. In addition, connexins located at non-canonical cell structures, including mitochondria and the nucleus, have been demonstrated to be involved in cardioprotection and in regulation of cell growth and differentiation. In this review, we will provide, first, an overview on connexin biology, including their synthesis and degradation, their regulation and their interactions. Then, we will conduct an in-depth examination of the role of connexins in cardiac pathophysiology, including new findings regarding their involvement in myocardial ischemia/reperfusion injury, cardiac fibrosis, gene transcription or signaling regulation.
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21
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Van Campenhout R, Gomes AR, De Groof TW, Muyldermans S, Devoogdt N, Vinken M. Mechanisms Underlying Connexin Hemichannel Activation in Disease. Int J Mol Sci 2021; 22:ijms22073503. [PMID: 33800706 PMCID: PMC8036530 DOI: 10.3390/ijms22073503] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 03/22/2021] [Accepted: 03/26/2021] [Indexed: 02/07/2023] Open
Abstract
Gap junctions and connexin hemichannels mediate intercellular and extracellular communication, respectively. While gap junctions are seen as the “good guys” by controlling homeostasis, connexin hemichannels are considered as the “bad guys”, as their activation is associated with the onset and dissemination of disease. Open connexin hemichannels indeed mediate the transport of messengers between the cytosol and extracellular environment and, by doing so, fuel inflammation and cell death in a plethora of diseases. The present mini-review discusses the mechanisms involved in the activation of connexin hemichannels during pathology.
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Affiliation(s)
- Raf Van Campenhout
- Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (R.V.C.); (A.R.G.)
| | - Ana Rita Gomes
- Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (R.V.C.); (A.R.G.)
| | - Timo W.M. De Groof
- Department of Medical Imaging, In Vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (T.W.M.D.G.); (N.D.)
| | - Serge Muyldermans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium;
| | - Nick Devoogdt
- Department of Medical Imaging, In Vivo Cellular and Molecular Imaging Laboratory, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (T.W.M.D.G.); (N.D.)
| | - Mathieu Vinken
- Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium; (R.V.C.); (A.R.G.)
- Correspondence: ; Tel.: +32-2-4774587
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22
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Riquelme MA, Gu S, Hua R, Jiang JX. Mechanotransduction via the coordinated actions of integrins, PI3K signaling and Connexin hemichannels. Bone Res 2021; 9:8. [PMID: 33531460 PMCID: PMC7854719 DOI: 10.1038/s41413-020-00126-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 09/25/2020] [Accepted: 10/14/2020] [Indexed: 12/11/2022] Open
Abstract
Mechanical loading opens connexin 43 (Cx43) hemichannels (HCs), leading to the release of bone anabolic molecules, such as prostaglandins, from mechanosensitive osteocytes, which is essential for bone formation and remodeling. However, the mechanotransduction mechanism that activates HCs remains elusive. Here, we report a unique pathway by which mechanical signals are effectively transferred between integrin molecules located in different regions of the cell, resulting in HC activation. Both integrin α5 and αV were activated upon mechanical stimulation via either fluid dropping or flow shear stress (FSS). Inhibition of integrin αV activation or ablation of integrin α5 prevented HC opening on the cell body when dendrites were mechanically stimulated, suggesting mechanical transmission from the dendritic integrin αV to α5 in the cell body during HC activation. In addition, HC function was compromised in vivo, as determined by utilizing an antibody blocking αV activation and α5-deficient osteocyte-specific knockout mice. Furthermore, inhibition of integrin αV activation, but not that of α5, attenuated activation of the phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) signaling pathway upon mechanical loading, and the inhibition of PI3K/AKT activation blocked integrin α5 activation and HC opening. Moreover, HC opening was blocked only by an anti-integrin αV antibody at low but not high FSS levels, suggesting that dendritic αV is a more sensitive mechanosensor than α5 for activating HCs. Together, these results reveal a new molecular mechanism of mechanotransduction involving the coordinated actions of integrins and PI3K/AKT in osteocytic dendritic processes and cell bodies that leads to HC opening and the release of key bone anabolic factors.
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Affiliation(s)
- Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229-3900, USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229-3900, USA
| | - Rui Hua
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229-3900, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229-3900, USA.
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23
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Xu W, Dielubanza E, Maisel A, Leung K, Mustoe T, Hong S, Galiano R. Staphylococcus aureus impairs cutaneous wound healing by activating the expression of a gap junction protein, connexin-43 in keratinocytes. Cell Mol Life Sci 2021; 78:935-947. [PMID: 32409862 PMCID: PMC11072219 DOI: 10.1007/s00018-020-03545-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 10/24/2022]
Abstract
Chronic wounds have been considered as major medical problems that may result in expensive healthcare. One of the common causes of chronic wounds is bacterial contamination that leads to persistent inflammation and unbalanced host cell immune responses. Among the bacterial strains that have been identified from chronic wounds, Staphylococcus aureus is the most common strain. We previously observed that S. aureus impaired mouse cutaneous wound healing by delaying re-epithelialization. Here, we investigated the mechanism of delayed re-epithelialization caused by S. aureus infection. With the presence of S. aureus exudate, the migration of in vitro cultured human keratinocytes was significantly inhibited and connexin-43 (Cx43) was upregulated. Inhibition of keratinocyte migration by S. aureus exudate disappeared in keratinocytes where the expression of Cx43 knocked down. Protein kinase phosphorylation array showed that phosphorylation of Akt-S473 was upregulated by S. aureus exudate. In vivo study of Cx43 in S. aureus-infected murine splinted cutaneous wound model showed upregulation of Cx43 in the migrating epithelial edge by S. aureus infection. Treatment with a PI3K/Akt inhibitor reduced Cx43 expression and overcame the wound closure impairment by S. aureus infection in the mouse model. This may contribute to the development of treatment to bacterium-infected wounds.
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Affiliation(s)
- Wei Xu
- Department of Life Sciences, College of Science and Engineering, Texas A&M University-Corpus Christi, Corpus Christi, TX, 78412, USA.
| | - Elodi Dielubanza
- Laboratory for Wound Repair and Regenerative Surgery, Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Amanda Maisel
- Laboratory for Wound Repair and Regenerative Surgery, Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Kai Leung
- Division of Combat Wound Repair, US Army Institute of Surgical Research, JB Fort Sam Houston, San Antonio, TX, 78234, USA
| | - Thomas Mustoe
- Laboratory for Wound Repair and Regenerative Surgery, Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Seok Hong
- Laboratory for Wound Repair and Regenerative Surgery, Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
| | - Robert Galiano
- Laboratory for Wound Repair and Regenerative Surgery, Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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24
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Usui Y, Watanabe M. Role of the Connexin C-terminus in skin pattern formation of Zebrafish. BBA ADVANCES 2021; 1:100006. [PMID: 37082017 PMCID: PMC10074918 DOI: 10.1016/j.bbadva.2021.100006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background Zebrafish display a striped skin pattern on their body; two types of connexins, namely, Connexin39.4 (Cx39.4) and Connexin41.8 (Cx41.8), are involved in stripe pattern formation. Herein, we investigated the role of the C-terminal (CT) domains of Cx39.4 and Cx41.8 in vivo and in vitro. Methods To investigate the role of CT domains in vivo, we established transgenic zebrafish lines expressing the CT-domain-modified connexin series in pigmented cells and observed skin patterns in fish. To investigate the role of the CT domains in vitro, we expressed the CT-domain modified connexin series in Neuro-2a (N2a) cells and calculated the plaque formation frequency. Results The overexpression of Cx39.4 lacking a CT domain produced skin patterns similar to that produced by full-length Cx39.4 in the cx39.4 -/- mutant and in cx39.4 and cx41.8 double-knockout mutant zebrafish. Fluorescence-protein-fused CT-domain-modified Cx39.4 formed gap junction plaques between N2a cells. The overexpression of CT-truncated Cx41.8 rescued the mutant phenotype in the cx41.8 -/- mutant but did not function in the double knockout zebrafish. Fluorescence-protein-fused CT-truncated Cx41.8 hardly formed plaques between N2a cells without Cx39.4 but formed gap junction plaques when co-expressed with Cx39.4. Conclusions The CT domain of Cx39.4 is not required for protein function, at least in the pigment cells of zebrafish. However, the need for the CT domain of Cx41.8 depends on Cx39.4 expression. General significance These results provide evidence for the interactions between Cx39.4 and Cx41.8 in pigment cells of zebrafish and suggest that at least one connexin must have a CT domain.
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25
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Zhao M, Hou S, Feng L, Shen P, Nan D, Zhang Y, Wang F, Ma D, Feng J. Vinpocetine Protects Against Cerebral Ischemia-Reperfusion Injury by Targeting Astrocytic Connexin43 via the PI3K/AKT Signaling Pathway. Front Neurosci 2020; 14:223. [PMID: 32300287 PMCID: PMC7142276 DOI: 10.3389/fnins.2020.00223] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/28/2020] [Indexed: 12/21/2022] Open
Abstract
Vinpocetine (Vinp) is known for its neuroprotective properties. However, the protective mechanism of Vinp against cerebral ischemia/reperfusion (I/R) injury should be further explored. This study was designed to investigate the neuroprotective effects of Vinp against oxygen-glucose deprivation/reoxygenation (OGD/R) injury in vitro and cerebral I/R injury in vivo and explore whether this mechanism would involve enhancement of astrocytic connexin 43 (Cx43) expression via the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway. In vitro, we detected astrocytic viability and extracellular nitric oxide by an assay kit, intracellular reactive oxygen species by a DCFH-DA probe, inflammation and apoptosis-related protein expression by immunofluorescence staining, and the astrocytic apoptosis rate by flow cytometry. In vivo, we measured the cerebral infarction volume, superoxide dismutase activity, malondialdehyde content, and the expression of inflammation and apoptosis-related proteins. The results indicated that Vinp ameliorated the detrimental outcome of I/R injury. Vinp attenuated astrocytic injury induced by OGD/R and reduced cerebral infarction volume and cerebral edema in rats with cerebral I/R injury. Moreover, Vinp reduced oxidative stress, inflammation, and apoptosis induced by cerebral I/R injury in brain tissues. Meanwhile, Vinp increased p-Cx43 and p-AKT expression, and the p-Cx43/Cx43 and p-AKT/AKT ratio, which was decreased by cerebral I/R injury. Coadministration of PI3K inhibitors LY294002 and BKM120 blunted the effects of Vinp. This study suggests that Vinp protects against cerebral I/R injury via Cx43 phosphorylation by activating the PI3K/AKT pathway.
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Affiliation(s)
- Mingming Zhao
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Shuai Hou
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Liangshu Feng
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Pingping Shen
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Di Nan
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Yunhai Zhang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China.,Jiangsu Key Laboratory of Medical Optics, Suzhou, China
| | - Famin Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, China.,Jiangsu Key Laboratory of Medical Optics, Suzhou, China
| | - Di Ma
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jiachun Feng
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
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Riquelme MA, Cardenas ER, Xu H, Jiang JX. The Role of Connexin Channels in the Response of Mechanical Loading and Unloading of Bone. Int J Mol Sci 2020; 21:ijms21031146. [PMID: 32050469 PMCID: PMC7038207 DOI: 10.3390/ijms21031146] [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: 01/02/2020] [Revised: 01/31/2020] [Accepted: 02/04/2020] [Indexed: 12/13/2022] Open
Abstract
The skeleton adapts to mechanical loading to promote bone formation and remodeling. While most bone cells are involved in mechanosensing, it is well accepted that osteocytes are the principal mechanosensory cells. The osteocyte cell body and processes are surrounded by a fluid-filled space, forming an extensive lacuno-canalicular network. The flow of interstitial fluid is a major stress-related factor that transmits mechanical stimulation to bone cells. The long dendritic processes of osteocytes form a gap junction channel network connecting not only neighboring osteocytes, but also cells on the bone surface, such as osteoblasts and osteoclasts. Mechanosensitive osteocytes also form hemichannels that mediate the communication between the cytoplasmic and extracellular microenvironment. This paper will discuss recent research progress regarding connexin (Cx)-forming gap junctions and hemichannels in osteocytes, osteoblasts, and other bone cells, including those richly expressing Cx43. We will then cover the recent progress regarding the regulation of these channels by mechanical loading and the role of integrins and signals in mediating Cx43 channels, and bone cell function and viability. Finally, we will summarize the recent studies regarding bone responses to mechanical unloading in Cx43 transgenic mouse models. The osteocyte has been perceived as the center of bone remodeling, and connexin channels enriched in osteocytes are a likely major player in meditating the function of bone. Based on numerous studies, connexin channels may present as a potential new therapeutic target in the treatment of bone loss and osteoporosis. This review will primarily focus on Cx43, with some discussion in other connexins expressed in bone cells.
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Affiliation(s)
- Manuel A. Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (M.A.R.); (E.R.C.)
| | - Eduardo R. Cardenas
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (M.A.R.); (E.R.C.)
| | - Huiyun Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an 710072, China;
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (M.A.R.); (E.R.C.)
- Correspondence: ; Tel.: +1-210-562-4094
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27
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Lagos-Cabré R, Burgos-Bravo F, Avalos AM, Leyton L. Connexins in Astrocyte Migration. Front Pharmacol 2020; 10:1546. [PMID: 32009957 PMCID: PMC6974553 DOI: 10.3389/fphar.2019.01546] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
Astrocytes have long been considered the supportive cells of the central nervous system, but during the last decades, they have gained much more attention because of their active participation in the modulation of neuronal function. For example, after brain damage, astrocytes become reactive and undergo characteristic morphological and molecular changes, such as hypertrophy and increase in the expression of glial fibrillary acidic protein (GFAP), in a process known as astrogliosis. After severe damage, astrocytes migrate to the lesion site and proliferate, which leads to the formation of a glial scar. At this scar-forming stage, astrocytes secrete many factors, such as extracellular matrix proteins, cytokines, growth factors and chondroitin sulfate proteoglycans, stop migrating, and the process is irreversible. Although reactive gliosis is a normal physiological response that can protect brain cells from further damage, it also has detrimental effects on neuronal survival, by creating a hostile and non-permissive environment for axonal repair. The transformation of astrocytes from reactive to scar-forming astrocytes highlights migration as a relevant regulator of glial scar formation, and further emphasizes the importance of efficient communication between astrocytes in order to orchestrate cell migration. The coordination between astrocytes occurs mainly through Connexin (Cx) channels, in the form of direct cell-cell contact (gap junctions, GJs) or contact between the extracellular matrix and the astrocytes (hemichannels, HCs). Reactive astrocytes increase the expression levels of several proteins involved in astrocyte migration, such as αvβ3 Integrin, Syndecan-4 proteoglycan, the purinergic receptor P2X7, Pannexin1, and Cx43 HCs. Evidence has indicated that Cx43 HCs play a role in regulating astrocyte migration through the release of small molecules to the extracellular space, which then activate receptors in the same or adjacent cells to continue the signaling cascades required for astrocyte migration. In this review, we describe the communication of astrocytes through Cxs, the role of Cxs in inflammation and astrocyte migration, and discuss the molecular mechanisms that regulate Cx43 HCs, which may provide a therapeutic window of opportunity to control astrogliosis and the progression of neurodegenerative diseases.
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Affiliation(s)
- Raúl Lagos-Cabré
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Francesca Burgos-Bravo
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Ana María Avalos
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
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Yang L, Zhou G, Li M, Li Y, Yang L, Fu Q, Tian Y. High Glucose Downregulates Connexin 43 Expression and Its Gap Junction and Hemichannel Function in Osteocyte-like MLO-Y4 Cells Through Activation of the p38MAPK/ERK Signal Pathway. Diabetes Metab Syndr Obes 2020; 13:545-557. [PMID: 32161481 PMCID: PMC7049751 DOI: 10.2147/dmso.s239892] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/16/2020] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Osteocyte network structure correlates with bone material quality. This network is profoundly altered in diabetic mice; however, the underlying mechanisms are unknown. The gap junction protein connexin 43 (Cx43) is necessary for normal osteocyte function and osteocyte network formation. Here, we evaluated Cx43 expression in patients with diabetes, the effect of high glucose on Cx43 expression, and the function of Cx43 gap junctions and hemichannels in osteocyte-like MLO-Y4 (MLO-Y4) cells. PATIENTS AND METHODS Human cortical bone samples were obtained from patients with or without type II diabetes mellitus (T2DM) who underwent arthroplasty surgery to treat osteoporosis-induced femoral neck fracture. UNLABELLED Cx43 expression was quantified in human cortical bone samples from both groups of patients and MLO-Y4 cells. The functions of Cx43 gap junctions and hemichannels in MLO-Y4 cells were evaluated using dye transfer and dye uptake assays, respectively. Furthermore, we evaluated levels of membrane Cx43 (mCx43), the functional form, and p38MAPK/ERK1/2 signaling, which is involved in mCx43 internalization, to characterize the mechanism of decreased Cx43 expression and gap junctions and hemichannels function. RESULTS Osteocyte Cx43 expression was decreased in femoral neck cortical bone samples of patients with T2DM patients compared with the non-diabetic control group. In addition, Cx43 expression was decreased in MLO-Y4 cells treated with high glucose. The functions of Cx43 gap junctions and hemichannels were inhibited in MLO-Y4 cells treated with high glucose. mCx43 expression was decreased in response to activation of p38-MAPK/ERK signaling. Inhibition of the p38-MAPK/ERK pathway partially reversed the decreases in Cx43 hemichannels and gap-junctions function. CONCLUSION High glucose dampened Cx43 gap junction and hemichannel function in MLO-Y4 cells by activating the p38MAPK/ERK pathway leading to subsequent mCx43 internalization.
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Affiliation(s)
- Lei Yang
- Orthopedics Department, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China
| | - Guangping Zhou
- Orthopedics Department, Shenyang Orthopedics Hospital, Shenyang, Liaoning Province, People’s Republic of China
| | - Mingyang Li
- Orthopedics Department, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China
| | - Yan Li
- Orthopedics Department, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China
| | - Liqing Yang
- Orthopedics Department, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China
| | - Qin Fu
- Orthopedics Department, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China
- Correspondence: Qin Fu Tel +86-18940251086 Email
| | - Ye Tian
- Orthopedics Department, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, People’s Republic of China
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29
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Wang Y, Yan Q, Zhao Y, Liu X, Lin S, Zhang P, Ma L, Lai Y, Bai X, Liu C, Wu C, Feng JQ, Chen D, Cao H, Xiao G. Focal adhesion proteins Pinch1 and Pinch2 regulate bone homeostasis in mice. JCI Insight 2019; 4:131692. [PMID: 31723057 DOI: 10.1172/jci.insight.131692] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/04/2019] [Indexed: 12/15/2022] Open
Abstract
Mammalian focal adhesion proteins Pinch1 and Pinch2 regulate integrin activation and cell-extracellular matrix adhesion and migration. Here, we show that deleting Pinch1 in osteocytes and mature osteoblasts using the 10-kb mouse Dmp1-Cre and Pinch2 globally (double KO; dKO) results in severe osteopenia throughout life, while ablating either gene does not cause bone loss, suggesting a functional redundancy of both factors in bone. Pinch deletion in osteocytes and mature osteoblasts generates signals that inhibit osteoblast and bone formation. Pinch-deficient osteocytes and conditioned media from dKO bone slice cultures contain abundant sclerostin protein and potently suppress osteoblast differentiation in primary BM stromal cells (BMSC) and calvarial cultures. Pinch deletion increases adiposity in the BM cavity. Primary dKO BMSC cultures display decreased osteoblastic but enhanced adipogenic, differentiation capacity. Pinch loss decreases expression of integrin β3, integrin-linked kinase (ILK), and α-parvin and increases that of active caspase-3 and -8 in osteocytes. Pinch loss increases osteocyte apoptosis in vitro and in bone. Pinch loss upregulates expression of both Rankl and Opg in the cortical bone and does not increase osteoclast formation and bone resorption. Finally, Pinch ablation exacerbates hindlimb unloading-induced bone loss and impairs active ulna loading-stimulated bone formation. Thus, we establish a critical role of Pinch in control of bone homeostasis.
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Affiliation(s)
- Yishu Wang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China.,Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Qinnan Yan
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Yiran Zhao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Xin Liu
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Simin Lin
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Peijun Zhang
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Liting Ma
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Yumei Lai
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA
| | - Xiaochun Bai
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Chuanju Liu
- Department of Orthopedic Surgery and.,Department of Cell Biology, New York University School of Medicine, New York, New York, USA
| | - Chuanyue Wu
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jian Q Feng
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - Di Chen
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA
| | - Huiling Cao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China
| | - Guozhi Xiao
- Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Shenzhen Key Laboratory of Cell Microenvironment, and.,Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China.,Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA
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30
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Abstract
PURPOSE OF REVIEW Osteocytes are responsible for mechanosensing and mechanotransduction in bone and play a crucial role in bone homeostasis. They are embedded in a calcified collagenous matrix and connected with each other through the lacuno-canalicular network. Due to this specific native environment, it is a challenge to isolate primary osteocytes without losing their specific characteristics in vitro. This review summarizes the commonly used and recently established models to study the function of osteocytes in vitro. RECENT FINDINGS Osteocytes are mostly studied in monolayer culture, but recently, 3D models of osteocyte-like cells and primary osteocytes in vitro have been established as well. These models mimic the native environment of osteocytes and show superior osteocyte morphology and behavior, enabling the development of human disease models. Osteocyte-like cell lines as well as primary osteocytes isolated from bone are widely used to study the role of osteocytes in bone homeostasis. Both cells lines and primary cells are cultured in 2D-monolayer and 3D-models. The use of these models and their advantages and shortcomings are discussed in this review.
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Affiliation(s)
- Chen Zhang
- Department of Oral Cell Biology, Amsterdam Movement Sciences, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Chemistry, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Astrid D Bakker
- Department of Oral Cell Biology, Amsterdam Movement Sciences, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Amsterdam Movement Sciences, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam Movement Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
- Department of Internal Medicine, Division of Endocrinology and Center for Bone Quality, Leiden University Medical Center, Leiden, The Netherlands.
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Connexin43 enhances Wnt and PGE2-dependent activation of β-catenin in osteoblasts. Pflugers Arch 2019; 471:1235-1243. [PMID: 31240382 DOI: 10.1007/s00424-019-02295-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/06/2019] [Accepted: 06/14/2019] [Indexed: 12/13/2022]
Abstract
Connexin43 is an important modulator of many signaling pathways in bone. β-Catenin, a key regulator of the osteoblast differentiation and function, is among the pathways downstream of connexin43-dependent intercellular communication. There are striking overlaps between the functions of these two proteins in bone cells. However, differential effects of connexin43 on β-catenin activity have been reported. Here, we examined how connexin43 influenced both Wnt-dependent and Wnt-independent activation of β-catenin in osteoblasts in vitro. Our data show that loss of connexin43 in primary osteoblasts or connexin43 overexpression in UMR106 cells regulated active β-catenin and phospho-Akt levels, with loss of connexin43 inhibiting and connexin43 overexpression increasing the levels of active β-catenin and phospho-Akt. Increasing connexin43 expression synergistically enhanced Wnt3a-dependent activation of β-catenin protein and β-catenin transcriptional activity, as well as Wnt-independent activation of β-catenin by prostaglandin E2 (PGE2). Finally, we show that the activation of β-catenin by PGE2 required signaling through the phosphatidylinositol 3-kinase (PI3K)/Akt/glycogen synthase kinase 3 beta (GSK3β) pathway, as the PI3K inhibitor, LY-294002, disrupted the synergy between connexin43 and PGE2. These data show that connexin43 regulates Akt and β-catenin activity and synergistically enhances both Wnt-dependent and Wnt-independent β-catenin signaling in osteoblasts.
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32
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Senescence-related deterioration of intercellular junctions in the peritoneal mesothelium promotes the transmesothelial invasion of ovarian cancer cells. Sci Rep 2019; 9:7587. [PMID: 31110245 PMCID: PMC6527686 DOI: 10.1038/s41598-019-44123-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/09/2019] [Indexed: 12/13/2022] Open
Abstract
Mechanisms of transmesothelial invasion of ovarian cancer are still poorly understood. Here we examined whether this phenomenon may be determined by an expression of intercellular junctions in peritoneal mesothelial cells (PMCs). Analysis of ovarian tumors showed that cancer cells are localized below an intact layer of PMCs. The PMCs located near the invaded cancer cells displayed low expression of connexin 43, E-cadherin, occludin, and desmoglein, as well as expressed SA-β-Gal, a marker of senescence. Experiments in vitro showed that senescent PMCs exhibited decreased levels of the four tested intercellular junctions, and that the invasion of ovarian cancer cells through the PMCs increased proportionally to the admixture of senescent cells. Intervention studies showed that the expression of connexin 43, E-cadherin, occludin, and desmoglein in senescent PMCs could be restored upon the blockade of p38 MAPK, NF-κB, AKT, JNK, HGF, and TGF-β1. When these molecules were neutralized, the efficiency of the transmesothelial cancer cell invasion was diminished. Collectively, our findings show that the integrity of the peritoneal mesothelium, which is determined by the expression of junctional proteins, is critical for the invasion of ovarian cancer. They also indicate a mechanism by which senescent PMCs may promote the invasive potential of cancer cells.
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Barrett DW, John RK, Thrasivoulou C, Mata A, Deprest JA, Becker DL, David AL, Chowdhury TT. Targeting mechanotransduction mechanisms and tissue weakening signals in the human amniotic membrane. Sci Rep 2019; 9:6718. [PMID: 31040291 PMCID: PMC6491562 DOI: 10.1038/s41598-019-42379-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 03/29/2019] [Indexed: 11/24/2022] Open
Abstract
Mechanical and inflammatory signals in the fetal membrane play an important role in extracellular matrix (ECM) remodelling in order to dictate the timing of birth. We developed a mechanical model that mimics repetitive stretching of the amniotic membrane (AM) isolated from regions over the placenta (PAM) or cervix (CAM) and examined the effect of cyclic tensile strain (CTS) on mediators involved in mechanotransduction (Cx43, AKT), tissue remodelling (GAGs, elastin, collagen) and inflammation (PGE2, MMPs). In CAM and PAM specimens, the application of CTS increased GAG synthesis, PGE2 release and MMP activity, with concomitant reduction in collagen and elastin content. Co-stimulation with CTS and pharmacological agents that inhibit either Cx43 or AKT, differentially influenced collagen, GAG and elastin in a tissue-dependent manner. SHG confocal imaging of collagen fibres revealed a reduction in SHG intensity after CTS, with regions of disorganisation dependent on tissue location. CTS increased Cx43 and AKT protein and gene expression and the response could be reversed with either CTS, the Cx43 antisense or AKT inhibitor. We demonstrate that targeting Cx43 and AKT prevents strain-induced ECM damage and promotes tissue remodelling mechanisms in the AM. We speculate that a combination of inflammatory and mechanical factors could perturb typical mechanotransduction processes mediated by Cx43 signalling. Cx43 could therefore be a potential therapeutic target to prevent inflammation and preterm premature rupture of the fetal membranes.
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Affiliation(s)
- David W Barrett
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Rebecca K John
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Christopher Thrasivoulou
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Alvaro Mata
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Jan A Deprest
- Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium
| | - David L Becker
- Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
| | - Anna L David
- Institute for Women's Health, University College London, 86-96 Chenies Mews, London, WC1E 6HX, UK
| | - Tina T Chowdhury
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival. Cancers (Basel) 2019; 11:cancers11020188. [PMID: 30736283 PMCID: PMC6406260 DOI: 10.3390/cancers11020188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 02/07/2023] Open
Abstract
Differential phosphorylation of the carboxyl-terminus of connexin 37 (Cx37-CT) regulates phenotypic switching between cell growth phenotypes (cell death, cell cycle arrest, proliferation). The specific phosphorylation events in the Cx37-CT that are necessary for these growth regulatory effects are currently unknown. Through the combined use of deletion and site specific (de)phospho-mimetic Cx37-CT mutants, our data suggest a phosphorylation-dependent interaction between the mid-tail (aa 273⁻317) and end-tail (aa 318⁻333) portions of the Cx37-CT that regulates cell survival. As detected by mass spectrometry, Cx37 was phosphorylated at serines 275, 321, and 328; phosphomimetic mutations of these sites resulted in cell death when expressed in rat insulinoma cells. Alanine substitution at S328, but not at S275 or S321, also triggered cell death. Cx37-S275D uniquely induced the death of only low density, non-contact forming cells, but neither hemichannel open probability nor channel conductance distinguished death-inducing mutants. As channel function is necessary for cell death, together the data suggest that the phosphorylation state of the Cx37-CT controls an intra-domain interaction within the CT that modifies channel function and induces cell death.
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35
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Plotkin LI, Bruzzaniti A. Molecular signaling in bone cells: Regulation of cell differentiation and survival. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:237-281. [PMID: 31036293 PMCID: PMC7416488 DOI: 10.1016/bs.apcsb.2019.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The achievement of proper bone mass and architecture, and their maintenance throughout life requires the concerted actions of osteoblasts, the bone forming cells, and osteoclasts, the bone resorbing cells. The differentiation and activity of osteoblasts and osteoclasts are regulated by molecules produced by matrix-embedded osteocytes, as well as by cross talk between osteoblasts and osteoclasts through secreted factors. In addition, it is likely that direct contact between osteoblast and osteoclast precursors, and the contact of these cells with osteocytes and cells in the bone marrow, also modulates bone cell differentiation and function. With the advancement of molecular and genetic tools, our comprehension of the intracellular signals activated in bone cells has evolved significantly, from early suggestions that osteoblasts and osteoclasts have common precursors and that osteocytes are inert cells in the bone matrix, to the very sophisticated understanding of a network of receptors, ligands, intracellular kinases/phosphatases, transcription factors, and cell-specific genes that are known today. These advances have allowed the design and FDA-approval of new therapies to preserve and increase bone mass and strength in a wide variety of pathological conditions, improving bone health from early childhood to the elderly. We have summarized here the current knowledge on selected intracellular signal pathways activated in osteoblasts, osteocytes, and osteoclasts.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States; Indiana Center for Musculoskeletal Health, Indianapolis, IN, United States; Roudebush Veterans Administration Medical Center, Indianapolis, IN, United States.
| | - Angela Bruzzaniti
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States; Indiana Center for Musculoskeletal Health, Indianapolis, IN, United States; Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indianapolis, IN, United States
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36
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Tao SC, Guo SC. Extracellular vesicles in bone: "dogrobbers" in the "eternal battle field". Cell Commun Signal 2019; 17:6. [PMID: 30658653 PMCID: PMC6339294 DOI: 10.1186/s12964-019-0319-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/06/2019] [Indexed: 02/07/2023] Open
Abstract
Throughout human life, bone is constantly in a delicate dynamic equilibrium of synthesis and resorption, hosting finely-tuned bone mineral metabolic processes for bone homeostasis by collaboration or symphony among several cell types including osteoclasts (OCs), osteoblasts (OBs), osteocytes (OYs), vascular endothelial cells (ECs) and their precursors. Beyond these connections, a substantial level of communication seems to occur between bone and other tissues, and together, they form an organic unit linked to human health and disease. However, the current hypothesis, which includes growth factors, hormones and specific protein secretion, incompletely explains the close connections among bone cells or between bone and other tissues. Extracellular vesicles (EVs) are widely-distributed membrane structures consisting of lipid bilayers, membrane proteins and intravesicular cargo (including proteins and nucleic acids), ranging from 30 nm to 1000 nm in diameter, and their characters have been highly conserved throughout evolution. EVs have targeting abilities and the potential to transmit multidimensional, abundant and complicated information, as powerful and substantial "dogrobbers" mediating intercellular communications. As research has progressed, EVs have gradually become thought of as "dogrobbers" in bone tissue-the "eternal battle field" -in a delicate dynamic balance of destruction and reconstruction. In the current review, we give a brief description of the major constituent cells in bone tissues and explore the progress of current research on bone-derived EVs. In addition, this review also discusses in depth not only potential directions for future research to breakthrough in this area but also problems existing in current research that need to be solved for a better understanding of bone tissues.
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Affiliation(s)
- Shi-Cong Tao
- Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China.
| | - Shang-Chun Guo
- Institute of Microsurgery on Extremities, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai, 200233, China.
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Connexins and Integrins in Exosomes. Cancers (Basel) 2019; 11:cancers11010106. [PMID: 30658425 PMCID: PMC6356207 DOI: 10.3390/cancers11010106] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/10/2019] [Accepted: 01/15/2019] [Indexed: 12/26/2022] Open
Abstract
Connexins and integrins, the two structurally and functionally distinct families of transmembrane proteins, have been shown to be inter-connected by various modes of cross-talk in cells, such as direct physical coupling via lateral contact, indirect physical coupling via actin and actin-binding proteins, and functional coupling via signaling cascades. This connexin-integrin cross-talk exemplifies a biologically important collaboration between channels and adhesion receptors in cells. Exosomes are biological lipid-bilayer nanoparticles secreted from virtually all cells via endosomal pathways into the extracellular space, thereby mediating intercellular communications across a broad range of health and diseases, including cancer progression and metastasis, infection and inflammation, and metabolic deregulation. Connexins and integrins are embedded in the exosomal membranes and have emerged as critical regulators of intercellular communication. This concise review article will explain and discuss recent progress in better understanding the roles of connexins, integrins, and their cross-talk in cells and exosomes.
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38
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Sera T, Arai M, Cui Z, Onose K, Karimi A, Kudo S. Unloading of intercellular tension induces the directional translocation of PKCα. J Cell Physiol 2018; 234:9764-9777. [PMID: 30387146 DOI: 10.1002/jcp.27662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/02/2018] [Indexed: 12/13/2022]
Abstract
The migration of endothelial cells (ECs) is closely associated with a Ca2+ -dependent protein, protein kinase Cα (PKCα). The disruption of intercellular adhesion by single-cell wounding has been shown to induce the directional translocation of PKCα. We hypothesized that this translocation of PKCα is induced by mechanical stress, such as unloading of intercellular tension, or by intercellular communication, such as gap junction-mediated and paracrine signaling. In the current study, we found that the disruption of intercellular adhesion induced the directional translocation of PKCα even when gap junction-mediated and paracrine signaling were inhibited. Conversely, it did not occur when the mechanosensitive channel was inhibited. In addition, the strain field of substrate attributable to the disruption of intercellular adhesion tended to be larger at the areas corresponding with PKCα translocation. Recently, we found that a direct mechanical stimulus induced the accumulation of PKCα at the stimulus area, involving Ca 2+ influx from extracellular space. These results indicated that the unloading of intercellular tension induced directional translocation of PKCα, which required Ca 2+ influx from extracellular space. The results of this study indicate the involvement of PKCα in the Ca 2+ signaling pathway in response to mechanical stress in ECs.
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Affiliation(s)
- Toshihiro Sera
- Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan
| | - Masataka Arai
- Department of Mechanical Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, Japan
| | - Zhonghua Cui
- Department of Mechanical Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, Japan
| | - Koichi Onose
- Department of Mechanical Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, Japan
| | - Alireza Karimi
- International Research Fellow, Faculty of Engineering, Kyushu University, Fukuoka, Japan
| | - Susumu Kudo
- Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan
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Treadmill Running Ameliorates Destruction of Articular Cartilage and Subchondral Bone, Not Only Synovitis, in a Rheumatoid Arthritis Rat Model. Int J Mol Sci 2018; 19:ijms19061653. [PMID: 29865282 PMCID: PMC6032207 DOI: 10.3390/ijms19061653] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/11/2022] Open
Abstract
We analyzed the influence of treadmill running on rheumatoid arthritis (RA) joints using a collagen-induced arthritis (CIA) rat model. Eight-week-old male Dark Agouti rats were randomly divided into four groups: The control group, treadmill group (30 min/day for 4 weeks from 10-weeks-old), CIA group (induced CIA at 8-weeks-old), and CIA + treadmill group. Destruction of the ankle joint was evaluated by histological analyses. Morphological changes of subchondral bone were analyzed by μ-CT. CIA treatment-induced synovial membrane invasion, articular cartilage destruction, and bone erosion. Treadmill running improved these changes. The synovial membrane in CIA rats produced a large amount of tumor necrosis factor-α and Connexin 43; production was significantly suppressed by treadmill running. On μ-CT of the talus, bone volume fraction (BV/TV) was significantly decreased in the CIA group. Marrow star volume (MSV), an index of bone loss, was significantly increased. These changes were significantly improved by treadmill running. Bone destruction in the talus was significantly increased with CIA and was suppressed by treadmill running. On tartrate-resistant acid phosphate and alkaline phosphatase (TRAP/ALP) staining, the number of osteoclasts around the pannus was decreased by treadmill running. These findings indicate that treadmill running in CIA rats inhibited synovial hyperplasia and joint destruction.
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Abstract
Major depressive disorder (MDD) is a chronic and debilitating illness that affects over 350 million people worldwide; however, current treatments have failed to cure or prevent the progress of depression. Increasing evidence suggests a crucial role for connexins in MDD. In this review, we have summarised recent accomplishments regarding the role of connexins, gap junctions, and hemichannels in the aetiology of MDD, and discussed the limitations of current research. A blockage of gap junctions or hemichannels induces depressive behaviour. Possible underlying mechanisms include the regulation of neurosecretory functions and synaptic activity by gap junctions and hemichannels. Gap junctions are functionally inhibited under stress conditions. Conversely, hemichannel permeability is increased. Antidepressants inhibit hemichannel permeability; however, they have contrasting effects on the function of gap junctions under normal conditions and can protect them against stress. In conclusion, the blockage of hemichannels concurrent with improvements in gap junction functionality might be potential targets for depression treatment.
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Affiliation(s)
- Cong-Yuan Xia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Tohru Yamakuni
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China.
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41
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Retamal MA, Riquelme MA, Stehberg J, Alcayaga J. Connexin43 Hemichannels in Satellite Glial Cells, Can They Influence Sensory Neuron Activity? Front Mol Neurosci 2017; 10:374. [PMID: 29200997 PMCID: PMC5696352 DOI: 10.3389/fnmol.2017.00374] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/27/2017] [Indexed: 12/30/2022] Open
Abstract
In this review article, we summarize the current insight on the role of Connexin- and Pannexin-based channels as modulators of sensory neurons. The somas of sensory neurons are located in sensory ganglia (i.e., trigeminal and nodose ganglia). It is well known that within sensory ganglia, sensory neurons do not form neither electrical nor chemical synapses. One of the reasons for this is that each soma is surrounded by glial cells, known as satellite glial cells (SGCs). Recent evidence shows that connexin43 (Cx43) hemichannels and probably pannexons located at SGCs have an important role in paracrine communication between glial cells and sensory neurons. This communication may be exerted via the release of bioactive molecules from SGCs and their subsequent action on receptors located at the soma of sensory neurons. The glio-neuronal communication seems to be relevant for the establishment of chronic pain, hyperalgesia and pathologies associated with tissue inflammation. Based on the current literature, it is possible to propose that Cx43 hemichannels expressed in SGCs could be a novel pharmacological target for treating chronic pain, which need to be directly evaluated in future studies.
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Affiliation(s)
- Mauricio A Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clinica Alemana Universidad del Desarrollo, Santiago, Chile.,Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Manuel A Riquelme
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Centro de Investigaciones Biomedicas, Universidad Andres Bello, Santiago, Chile
| | - Julio Alcayaga
- Department of Biology, Cell Physiology Center, University of Chile, Santiago, Chile
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42
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Uchida M, Anderson EL, Squillace DL, Patil N, Maniak PJ, Iijima K, Kita H, O'Grady SM. Oxidative stress serves as a key checkpoint for IL-33 release by airway epithelium. Allergy 2017; 72:1521-1531. [PMID: 28273344 DOI: 10.1111/all.13158] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Interleukin (IL)-33 is implicated in the pathophysiology of asthma and allergic diseases. However, our knowledge is limited regarding how IL-33 release is controlled. The transcription factor nuclear factor-erythroid-2-related factor 2 (Nrf2) plays a key role in antioxidant response regulation. OBJECTIVE The goal of this project was to investigate the role of cellular oxidative stress in controlling IL-33 release in airway epithelium. METHODS Complementary approaches were used that included human bronchial epithelial cells and mouse models of airway type-2 immunity that were exposed to fungus Alternaria extract. The clinically available Nrf2 activator 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid methyl ester (CDDO-Me) was used to evaluate the role of Nrf2-induced antioxidant molecules. RESULTS Human bronchial epithelial cells produced reactive oxygen species (ROS) when they were exposed to Alternaria extract. ROS scavengers, such as glutathione (GSH) and N-acetyl cysteine, prevented extracellular secretion of ATP and increases in intracellular calcium concentrations that precede IL-33 release. Administration of CDDO-Me to mice enhanced expression of a number of antioxidant molecules in the lungs and elevated lung levels of endogenous GSH. Importantly, CDDO-Me treatment reduced allergen-induced ATP secretion and IL-33 release by airway epithelial cells in vitro and protected mice from IL-33 release and asthma-like pathological changes in the lungs. CONCLUSIONS The balance between oxidative stress and antioxidant responses plays a key role in controlling IL-33 release in airway epithelium. The therapeutic potential of Nrf2 activators needs to be considered for asthma and allergic airway diseases.
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Affiliation(s)
- M. Uchida
- Division of Allergic Diseases; Department of Internal Medicine; Mayo Clinic; Rochester MN USA
- Division of Hematology; Respiratory Medicine and Oncology; Department of Internal Medicine; Faculty of Medicine; Saga University; Saga Japan
| | | | - D. L. Squillace
- Division of Allergic Diseases; Department of Internal Medicine; Mayo Clinic; Rochester MN USA
| | - N. Patil
- Departments of Integrated Biology and Physiology and Animal Science; University of Minnesota; St. Paul MN USA
| | - P. J. Maniak
- Departments of Integrated Biology and Physiology and Animal Science; University of Minnesota; St. Paul MN USA
| | - K. Iijima
- Division of Allergic Diseases; Department of Internal Medicine; Mayo Clinic; Rochester MN USA
| | - H. Kita
- Division of Allergic Diseases; Department of Internal Medicine; Mayo Clinic; Rochester MN USA
- Department of Immunology; Mayo Clinic; Rochester MN USA
| | - S. M. O'Grady
- Departments of Integrated Biology and Physiology and Animal Science; University of Minnesota; St. Paul MN USA
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Corneal Endothelial Cell Integrity in Precut Human Donor Corneas Enhanced by Autocrine Vasoactive Intestinal Peptide. Cornea 2017; 36:476-483. [PMID: 28181929 PMCID: PMC5334175 DOI: 10.1097/ico.0000000000001136] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To demonstrate that vasoactive intestinal peptide (VIP), a corneal endothelial (CE) cell autocrine factor, maintains the integrity of corneal endothelium in human donor corneoscleral explants precut for endothelial keratoplasty. METHODS Twelve paired human donor corneoscleral explants used as control versus VIP-treated explants (10 nM, 30 minutes, 37°C) were shipped (4°C) to the Lions Eye Institute for Transplantation and Research for precutting (Moria CBM-ALTK Keratome), shipped back to the laboratory, and cultured in ciliary neurotrophic factor (CNTF, 0.83 nM, 37°C, 24 hours). Trephined endothelial discs (8-8.5 mm) were analyzed for differentiation markers (N-cadherin, CNTF receptor α subunit [CNTFRα], and connexin 43) by Western blot after a quarter of the discs from 4 paired explants were cut away and stained with alizarin red S for microscopic damage analysis. Two additional paired explants (6 days in culture) were stained for panoramic view of central CE damage. RESULTS VIP treatment increased N-cadherin and CNTFRα levels (mean ± SEM) to 1.38 ± 0.11-fold (P = 0.003) and 1.46 ± 0.22-fold (P = 0.03) of paired controls, respectively, whereas CE cell CNTF responsiveness in upregulation of connexin 43 increased to 2.02 ± 0.5 (mean ± SEM)-fold of the controls (P = 0.04). CE damage decreased from (mean ± SEM) 10.0% ± 1.2% to 1.6% ± 0.3% (P < 0.0001) and 9.1% ± 1.1% to 2.4% ± 1.0% (P = 0.0006). After 6 days in culture, the damage in whole CE discs decreased from 20.0% (control) to 5.5% (VIP treated). CONCLUSIONS VIP treatment before precut enhanced the preservation of corneal endothelium.
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Kuroshima S, Kaku M, Ishimoto T, Sasaki M, Nakano T, Sawase T. A paradigm shift for bone quality in dentistry: A literature review. J Prosthodont Res 2017. [PMID: 28633987 DOI: 10.1016/j.jpor.2017.05.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE The aim of this study was to present the current concept of bone quality based on the proposal by the National Institutes of Health (NIH) and some of the cellular and molecular factors that affect bone quality. STUDY SELECTION This is a literature review which focuses on collagen, biological apatite (BAp), and bone cells such as osteoblasts and osteocytes. RESULTS In dentistry, the term "bone quality" has long been considered to be synonymous with bone mineral density (BMD) based on radiographic and sensible evaluations. In 2000, the NIH proposed the concept of bone quality as "the sum of all characteristics of bone that influence the bone's resistance to fracture," which is completely independent of BMD. The NIH defines bone quality as comprising bone architecture, bone turnover, bone mineralization, and micro-damage accumulation. Moreover, our investigations have demonstrated that BAp, collagen, and bone cells such as osteoblasts and osteocytes play essential roles in controlling the current concept of bone quality in bone around hip and dental implants. CONCLUSION The current concept of bone quality is crucial for understanding bone mechanical functions. BAp, collagen and osteocytes are the main factors affecting bone quality. Moreover, mechanical loading dynamically adapts bone quality. Understanding the current concept of bone quality is required in dentistry.
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Affiliation(s)
- Shinichiro Kuroshima
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1, Sakamoto, Nagasaki-city, Nagasaki 852-8588, Japan.
| | - Masaru Kaku
- Division of Bio-prosthodontics, Graduate School of Medical and Dental Science, Niigata University, 2-5274, Gakkocho-dori, Chuo-ku, Niigata-City, Niigata 951-8514, Japan
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita-city, Osaka 565-0871, Japan
| | - Muneteru Sasaki
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1, Sakamoto, Nagasaki-city, Nagasaki 852-8588, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita-city, Osaka 565-0871, Japan
| | - Takashi Sawase
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1, Sakamoto, Nagasaki-city, Nagasaki 852-8588, Japan
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Xu H, Liu R, Ning D, Zhang J, Yang R, Riquelme MA, Li J, Jiang JX, Shang P. Biological responses of osteocytic connexin 43 hemichannels to simulated microgravity. J Orthop Res 2017; 35:1195-1202. [PMID: 26945892 PMCID: PMC5726230 DOI: 10.1002/jor.23224] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 02/23/2016] [Indexed: 02/04/2023]
Abstract
Connexin 43 (Cx43) hemichannels and gap junctions in osteocytes are responsive to mechanical loading, which is important for bone formation and remodeling. However, the mechanism of these Cx43-forming channels in the process of mechanical unloading is still not very clear. In this study, unloading caused by weightlessness was simulated by using a random position machine (RPM). Osteocytic MLO-Y4 cells were subjected to 2 h of RPM treatment, and levels of Cx43 mRNA and total and cell surface expressed protein were determined by quantitative real-time PCR, western blotting, and biotinylation analysis. Although mRNA was elevated by RPM, total protein level of Cx43 was not altered; however, surface biotinylated Cx43 was significantly reduced. Interestingly, RPM promoted the retention of Cx43 in the Golgi apparatus detected by co-immunofluorescence with antibodies against Cx43 and 58 K Golgi marker protein. Dye uptake assay showed that hemichannels were induced open after RPM for 2 h. Consistently, prostaglandin E2 release was increased and this increase was completely attenuated with the treatment of a Cx43 hemichannel blocking antibody. Together, this study demonstrates increased activity of Cx43 hemichannels to RPM, and active Cx43 hemichannels with prostaglandin E2 release are likely to module biological function under simulated weightless conditions. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1195-1202, 2017.
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Affiliation(s)
- Huiyun Xu
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Ruofei Liu
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Dandan Ning
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Jian Zhang
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Ruixin Yang
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Manuel A. Riquelme
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Jingbao Li
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
| | - Jean X. Jiang
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Peng Shang
- Key Laboratory for Space Biosciences and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, Shaanxi, China
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Leithe E, Mesnil M, Aasen T. The connexin 43 C-terminus: A tail of many tales. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:48-64. [PMID: 28526583 DOI: 10.1016/j.bbamem.2017.05.008] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
Abstract
Connexins are chordate gap junction channel proteins that, by enabling direct communication between the cytosols of adjacent cells, create a unique cell signalling network. Gap junctional intercellular communication (GJIC) has important roles in controlling cell growth and differentiation and in tissue development and homeostasis. Moreover, several non-canonical connexin functions unrelated to GJIC have been discovered. Of the 21 members of the human connexin family, connexin 43 (Cx43) is the most widely expressed and studied. The long cytosolic C-terminus (CT) of Cx43 is subject to extensive post-translational modifications that modulate its intracellular trafficking and gap junction channel gating. Moreover, the Cx43 CT contains multiple domains involved in protein interactions that permit crosstalk between Cx43 and cytoskeletal and regulatory proteins. These domains endow Cx43 with the capacity to affect cell growth and differentiation independently of GJIC. Here, we review the current understanding of the regulation and unique functions of the Cx43 CT, both as an essential component of full-length Cx43 and as an independent signalling hub. We highlight the complex regulatory and signalling networks controlled by the Cx43 CT, including the extensive protein interactome that underlies both gap junction channel-dependent and -independent functions. We discuss these data in relation to the recent discovery of the direct translation of specific truncated forms of Cx43. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, University of Oslo, NO-0424 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, NO-0424 Oslo, Norway
| | - Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, France
| | - Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
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Qin Y, Peng Y, Zhao W, Pan J, Ksiezak-Reding H, Cardozo C, Wu Y, Divieti Pajevic P, Bonewald LF, Bauman WA, Qin W. Myostatin inhibits osteoblastic differentiation by suppressing osteocyte-derived exosomal microRNA-218: A novel mechanism in muscle-bone communication. J Biol Chem 2017; 292:11021-11033. [PMID: 28465350 DOI: 10.1074/jbc.m116.770941] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/26/2017] [Indexed: 12/25/2022] Open
Abstract
Muscle and bone are closely associated in both anatomy and function, but the mechanisms that coordinate their synergistic action remain poorly defined. Myostatin, a myokine secreted by muscles, has been shown to inhibit muscle growth, and the disruption of the myostatin gene has been reported to cause muscle hypertrophy and increase bone mass. Extracellular vesicle-exosomes that carry microRNA (miRNA), mRNA, and proteins are known to perform an important role in cell-cell communication. We hypothesized that myostatin may play a crucial role in muscle-bone interactions and may promote direct effects on osteocytes and on osteocyte-derived exosomal miRNAs, thereby indirectly influencing the function of other bone cells. We report herein that myostatin promotes expression of several bone regulators such as sclerostin (SOST), DKK1, and RANKL in cultured osteocytic (Ocy454) cells, concomitant with the suppression of miR-218 in both parent Ocy454 cells and derived exosomes. Exosomes produced by Ocy454 cells that had been pretreated with myostatin could be taken up by osteoblastic MC3T3 cells, resulting in a marked reduction of Runx2, a key regulator of osteoblastic differentiation, and in decreased osteoblastic differentiation via the down-regulation of the Wnt signaling pathway. Importantly, the inhibitory effect of myostatin-modified osteocytic exosomes on osteoblast differentiation is completely reversed by expression of exogenous miR-218, through a mechanism involving miR-218-mediated inhibition of SOST. Together, our findings indicate that myostatin directly influences osteocyte function and thereby inhibits osteoblastic differentiation, at least in part, through the suppression of osteocyte-derived exosomal miR-218, suggesting a novel mechanism in muscle-bone communication.
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Affiliation(s)
- Yiwen Qin
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | - Yuanzhen Peng
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | - Wei Zhao
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | - Jianping Pan
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| | | | - Christopher Cardozo
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468.,the Departments of Medicine.,Rehabilitation Medicine, and
| | - Yingjie Wu
- the Departments of Medicine.,Institute of Gene Engineering Animal Models for Human Diseases, Dalian Medical University, Dalian 116044, China
| | - Paola Divieti Pajevic
- the Department of Molecular and Cell Biology, Boston University, Boston, Massachusetts 02215, and
| | - Lynda F Bonewald
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - William A Bauman
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468.,the Departments of Medicine.,Rehabilitation Medicine, and
| | - Weiping Qin
- From the National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468, .,the Departments of Medicine
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Laurent MR, Dubois V, Claessens F, Verschueren SMP, Vanderschueren D, Gielen E, Jardí F. Muscle-bone interactions: From experimental models to the clinic? A critical update. Mol Cell Endocrinol 2016; 432:14-36. [PMID: 26506009 DOI: 10.1016/j.mce.2015.10.017] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023]
Abstract
Bone is a biomechanical tissue shaped by forces from muscles and gravitation. Simultaneous bone and muscle decay and dysfunction (osteosarcopenia or sarco-osteoporosis) is seen in ageing, numerous clinical situations including after stroke or paralysis, in neuromuscular dystrophies, glucocorticoid excess, or in association with vitamin D, growth hormone/insulin like growth factor or sex steroid deficiency, as well as in spaceflight. Physical exercise may be beneficial in these situations, but further work is still needed to translate acceptable and effective biomechanical interventions like vibration therapy from animal models to humans. Novel antiresorptive and anabolic therapies are emerging for osteoporosis as well as drugs for sarcopenia, cancer cachexia or muscle wasting disorders, including antibodies against myostatin or activin receptor type IIA and IIB (e.g. bimagrumab). Ideally, increasing muscle mass would increase muscle strength and restore bone loss from disuse. However, the classical view that muscle is unidirectionally dominant over bone via mechanical loading is overly simplistic. Indeed, recent studies indicate a role for neuronal regulation of not only muscle but also bone metabolism, bone signaling pathways like receptor activator of nuclear factor kappa-B ligand (RANKL) implicated in muscle biology, myokines affecting bone and possible bone-to-muscle communication. Moreover, pharmacological strategies inducing isolated myocyte hypertrophy may not translate into increased muscle power because tendons, connective tissue, neurons and energy metabolism need to adapt as well. We aim here to critically review key musculoskeletal molecular pathways involved in mechanoregulation and their effect on the bone-muscle unit as a whole, as well as preclinical and emerging clinical evidence regarding the effects of sarcopenia therapies on osteoporosis and vice versa.
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Affiliation(s)
- Michaël R Laurent
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dubois
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Frank Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Sabine M P Verschueren
- Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Science, KU Leuven, 3000 Leuven, Belgium
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Evelien Gielen
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Ferran Jardí
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
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49
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Johnson RG, Le HC, Evenson K, Loberg SW, Myslajek TM, Prabhu A, Manley AM, O’Shea C, Grunenwald H, Haddican M, Fitzgerald PM, Robinson T, Cisterna BA, Sáez JC, Liu TF, Laird DW, Sheridan JD. Connexin Hemichannels: Methods for Dye Uptake and Leakage. J Membr Biol 2016; 249:713-741. [DOI: 10.1007/s00232-016-9925-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/22/2016] [Indexed: 01/18/2023]
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50
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Boyer A, Girard M, Thimmanahalli DS, Levasseur A, Céleste C, Paquet M, Duggavathi R, Boerboom D. mTOR Regulates Gap Junction Alpha-1 Protein Trafficking in Sertoli Cells and Is Required for the Maintenance of Spermatogenesis in Mice. Biol Reprod 2016; 95:13. [PMID: 27281705 PMCID: PMC5029431 DOI: 10.1095/biolreprod.115.138016] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/14/2016] [Accepted: 05/17/2016] [Indexed: 12/29/2022] Open
Abstract
The mammalian target of rapamycin (Mtor) gene encodes a serine/threonine kinase that acts as a master regulator of processes as diverse as cell growth, protein synthesis, cytoskeleton reorganization, and cell survival. In the testis, physiological roles for Mtor have been proposed in perinatal Sertoli cell proliferation and blood-testis barrier (BTB) remodeling during spermatogenesis, but no in vivo studies of Mtor function have been reported. Here, we used a conditional knockout approach to target Mtor in Sertoli cells. The resulting Mtor(flox/flox); Amhr2(cre/+) mice were characterized by progressive, adult-onset testicular atrophy associated with disorganization of the seminiferous epithelium, loss of Sertoli cell polarity, increased germ cell apoptosis, premature release of germ cells, decreased epididymal sperm counts, increased sperm abnormalities, and infertility. Histopathologic analysis and quantification of the expression of stage-specific markers showed a specific loss of pachytene spermatocytes and spermatids. Although the BTB and the ectoplasmic specializations did not appear to be altered in Mtor(flox/flox);Amhr2(cre/+) mice, a dramatic redistribution of gap junction alpha-1 (GJA1) was detected in their Sertoli cells. Phosphorylation of GJA1 at Ser373, which is associated with its internalization, was increased in the testes of Mtor(flox/flox); Amhr2(cre/+) mice, as was the expression and phosphorylation of AKT, which phosphorylates GJA1 at this site. Together, these results indicate that Mtor expression in Sertoli cells is required for the maintenance of spermatogenesis and the progression of germ cell development through the pachytene spermatocyte stage. One mechanism of mTOR action may be to regulate gap junction dynamics by inhibiting AKT, thereby decreasing GJA1 phosphorylation and internalization. mTOR regulates gap junction alpha-1 protein distribution in Sertoli cells and is necessary for progression through the pachytene spermatocyte stage.
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Affiliation(s)
- Alexandre Boyer
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Québec, Canada
| | - Meggie Girard
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Québec, Canada
| | | | - Adrien Levasseur
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Québec, Canada
| | - Christophe Céleste
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Québec, Canada
| | - Marilène Paquet
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Québec, Canada
| | - Rajesha Duggavathi
- Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Québec, Canada
| | - Derek Boerboom
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Québec, Canada
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