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He X, Yamada M, Watanabe J, Pengyu Q, Chen J, Egusa H. Titanium nanotopography enhances mechano-response of osteocyte three-dimensional network toward osteoblast activation. BIOMATERIALS ADVANCES 2024; 163:213939. [PMID: 38954876 DOI: 10.1016/j.bioadv.2024.213939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 06/19/2024] [Accepted: 06/27/2024] [Indexed: 07/04/2024]
Abstract
The bone turnover capability influences the acquisition and maintenance of osseointegration. The architectures of osteocyte three-dimensional (3D) networks determine the direction and activity of bone turnover through osteocyte intercellular crosstalk, which exchanges prostaglandins through gap junctions in response to mechanical loading. Titanium nanosurfaces with anisotropically patterned dense nanospikes promote the development of osteocyte lacunar-canalicular networks. We investigated the effects of titanium nanosurfaces on intercellular network development and regulatory capabilities of bone turnover in osteocytes under cyclic compressive loading. MLO-Y4 mouse osteocyte-like cell lines embedded in type I collagen 3D gels on titanium nanosurfaces promoted the formation of intercellular networks and gap junctions even under static culture conditions, in contrast to the poor intercellular connectivity in machined titanium surfaces. The osteocyte 3D network on the titanium nanosurfaces further enhanced gap junction formation after additional culturing under cyclic compressive loading simulating masticatory loading, beyond the degree observed on machined titanium surfaces. A prostaglandin synthesis inhibitor cancelled the dual effects of titanium nanosurfaces and cyclic compressive loading on the upregulation of gap junction-related genes in the osteocyte 3D culture. Supernatants from osteocyte monolayer culture on titanium nanosurfaces promoted osteocyte maturation and intercellular connections with gap junctions. With cyclic loading, titanium nanosurfaces induced expression of the regulatory factors of bone turnover in osteocyte 3D cultures, toward higher osteoblast activation than that observed on machined surfaces. Titanium nanosurfaces with anisotropically patterned dense nanospikes promoted intercellular 3D network development and regulatory function toward osteoblast activation in osteocytes activated by cyclic compressive loading, through intercellular crosstalk by prostaglandin.
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Affiliation(s)
- Xindie He
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan; Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Masahiro Yamada
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
| | - Jun Watanabe
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
| | - Qu Pengyu
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
| | - Jiang Chen
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Hiroshi Egusa
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan; Center for Advanced Stem Cell and Regenerative Research, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
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Fernandes CJC, Silva RA, Ferreira MR, Fuhler GM, Peppelenbosch MP, van der Eerden BC, Zambuzzi WF. Vascular smooth muscle cell-derived exosomes promote osteoblast-to-osteocyte transition via β-catenin signaling. Exp Cell Res 2024; 442:114211. [PMID: 39147261 DOI: 10.1016/j.yexcr.2024.114211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 08/01/2024] [Accepted: 08/13/2024] [Indexed: 08/17/2024]
Abstract
Blood vessel growth and osteogenesis in the skeletal system are coupled; however, fundamental aspects of vascular function in osteoblast-to-osteocyte transition remain unclear. Our study demonstrates that vascular smooth muscle cells (VSMCs), but not endothelial cells, are sufficient to drive bone marrow mesenchymal stromal cell-derived osteoblast-to-osteocyte transition via β-catenin signaling and exosome-mediated communication. We found that VSMC-derived exosomes are loaded with transcripts encoding proteins associated with the osteocyte phenotype and members of the WNT/β-catenin signaling pathway. In contrast, endothelial cell-derived exosomes facilitated mature osteoblast differentiation by reprogramming the TGFB1 gene family and osteogenic transcription factors osterix (SP7) and RUNX2. Notably, VSMCs express significant levels of tetraspanins (CD9, CD63, and CD81) and drive the intracellular trafficking of exosomes with a lower membrane zeta potential than those from other cells. Additionally, the high ATP content within these exosomes supports mineralization mechanisms, as ATP is a substrate for alkaline phosphatase. Osteocyte function was further validated by RNA sequencing, revealing activity in genes related to intermittent mineralization and sonic hedgehog signaling, alongside a significant increase in TNFSF11 levels. Our findings unveil a novel role of VSMCs in promoting osteoblast-to-osteocyte transition, thus offering new insights into bone biology and homeostasis, as well as in bone-related diseases. Clinically, these insights could pave the way for innovative therapeutic strategies targeting VSMC-derived exosome pathways to treat bone-related disorders such as osteoporosis. By manipulating these signaling pathways, it may be possible to enhance bone regeneration and improve skeletal health in patients with compromised bone structure and function.
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Affiliation(s)
- Célio J C Fernandes
- Bioassays and Cell Dynamics Lab, Dept. of Chemistry and Biochemistry, Bioscience Institute, UNESP, Botucatu, 18603-100, Sao Paulo, Brazil
| | - Rodrigo A Silva
- School of Dentistry, University of Taubaté, 12020-340, Taubaté, São Paulo, Brazil
| | - Marcel R Ferreira
- Bioassays and Cell Dynamics Lab, Dept. of Chemistry and Biochemistry, Bioscience Institute, UNESP, Botucatu, 18603-100, Sao Paulo, Brazil
| | - Gwenny M Fuhler
- Department of Gastroenterology and Hepatology, Erasmus MC, Erasmus University Medical Center, Dr Molewaterplein 40, 3015 GD, Rotterdam, the Netherlands
| | - Maikel P Peppelenbosch
- Department of Gastroenterology and Hepatology, Erasmus MC, Erasmus University Medical Center, Dr Molewaterplein 40, 3015 GD, Rotterdam, the Netherlands
| | - Bram Cj van der Eerden
- Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Dr Molewaterplein 40, 3015 GD, Rotterdam, the Netherlands
| | - Willian F Zambuzzi
- Bioassays and Cell Dynamics Lab, Dept. of Chemistry and Biochemistry, Bioscience Institute, UNESP, Botucatu, 18603-100, Sao Paulo, Brazil.
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Ma L, Wang W, Xu G, Li H, Liu F, Shao H, Zhang X, Ma Y, Li G, Li H, Gao S, Ling P. Connexin 43 in the function and homeostasis of osteocytes: a narrative review. ANNALS OF JOINT 2023; 9:10. [PMID: 38529291 PMCID: PMC10929443 DOI: 10.21037/aoj-23-65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/29/2023] [Indexed: 03/27/2024]
Abstract
Background and Objective Connexin 43 (Cx43) is the main gap junction (GJ) protein and hemichannel protein in bone tissue. It is involved in the formation of hemichannels and GJs and establishes channels that can communicate directly to exchange substances and signals, affecting the structure and function of osteocytes. CX43 is very important for the normal development of bone tissue and the establishment and balance of bone reconstruction. However, the molecular mechanisms by which CX43 regulates osteoblast function and homeostasis have been less well studied, and this article provides a review of research in this area. Methods We searched the PubMed, EMBASE, Cochrane Library, and Web of Science databases for studies published up to June 2023 using the keywords Connexin 43/Cx43 and Osteocytes. Screening of literatures according to inclusion and exclusion guidelines and summarized the results. Key Content and Findings Osteocytes, osteoblasts, and osteoclasts all express Cx43 and form an overall network through the interaction between GJs. Cx43 is not only involved in the mechanical response of bone tissue but also in the regulation of signal transduction, which could provide new molecular markers and novel targets for the treatment of certain bone diseases. Conclusions Cx43 is expressed in osteoblasts, osteoclasts, and osteoclasts and plays an important role in regulating the function, signal transduction, and mechanotransduction of osteocytes. This review offers a new contribution to the literature by summarizing the relationship between Cx43, a key protein of bone tissue, and osteoblasts.
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Affiliation(s)
- Liang Ma
- Department of Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Wenzhao Wang
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Guixuan Xu
- Department of Pathology and Medical Research Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Hao Li
- Department of Joint Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Fei Liu
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Huarong Shao
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Xiuhua Zhang
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
| | - Yuxia Ma
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Gang Li
- Department of Orthopedics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Hui Li
- Department of Operating Room, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Shuzhong Gao
- Post-doctoral Station of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Peixue Ling
- Post-doctoral Scientific Research Workstation, Shandong Academy of Pharmaceutical Science, Jinan, China
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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide a background on osteocytes and the primary cilium, discussing the role it plays in osteocyte mechanosensing. RECENT FINDINGS Osteocytes are thought to be the primary mechanosensing cells in bone tissue, regulating bone adaptation in response to exercise, with the primary cilium suggested to be a key mechanosensing mechanism in bone. More recent work has suggested that, rather than being direct mechanosensors themselves, primary cilia in bone may instead form a key chemo-signalling nexus for processing mechanoregulated signalling pathways. Recent evidence suggests that pharmacologically induced lengthening of the primary cilium in osteocytes may potentiate greater mechanotransduction, rather than greater mechanosensing. While more research is required to delineate the specific osteocyte mechanobiological molecular mechanisms governed by the primary cilium, it is clear from the literature that the primary cilium has significant potential as a therapeutic target to treat mechanoregulated bone diseases, such as osteoporosis.
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Affiliation(s)
- Stefaan W Verbruggen
- Department of Mechanical Engineering, University of Sheffield, Sheffield, UK.
- INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK.
- Centre for Predictive in vitro Models, Centre for Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, UK.
| | - Anuphan Sittichokechaiwut
- Department of Preventive Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand
- Center of Excellence in Biomaterials, Naresuan University, Phitsanulok, Thailand
| | - Gwendolen C Reilly
- INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK
- Kroto Research Institute, Department of Materials Science and Engineering, University of Sheffield, Sheffield, UK
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LaGuardia JS, Shariati K, Bedar M, Ren X, Moghadam S, Huang KX, Chen W, Kang Y, Yamaguchi DT, Lee JC. Convergence of Calcium Channel Regulation and Mechanotransduction in Skeletal Regenerative Biomaterial Design. Adv Healthc Mater 2023; 12:e2301081. [PMID: 37380172 PMCID: PMC10615747 DOI: 10.1002/adhm.202301081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/20/2023] [Indexed: 06/30/2023]
Abstract
Cells are known to perceive their microenvironment through extracellular and intracellular mechanical signals. Upon sensing mechanical stimuli, cells can initiate various downstream signaling pathways that are vital to regulating proliferation, growth, and homeostasis. One such physiologic activity modulated by mechanical stimuli is osteogenic differentiation. The process of osteogenic mechanotransduction is regulated by numerous calcium ion channels-including channels coupled to cilia, mechanosensitive and voltage-sensitive channels, and channels associated with the endoplasmic reticulum. Evidence suggests these channels are implicated in osteogenic pathways such as the YAP/TAZ and canonical Wnt pathways. This review aims to describe the involvement of calcium channels in regulating osteogenic differentiation in response to mechanical loading and characterize the fashion in which those channels directly or indirectly mediate this process. The mechanotransduction pathway is a promising target for the development of regenerative materials for clinical applications due to its independence from exogenous growth factor supplementation. As such, also described are examples of osteogenic biomaterial strategies that involve the discussed calcium ion channels, calcium-dependent cellular structures, or calcium ion-regulating cellular features. Understanding the distinct ways calcium channels and signaling regulate these processes may uncover potential targets for advancing biomaterials with regenerative osteogenic capabilities.
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Affiliation(s)
- Jonnby S. LaGuardia
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Kaavian Shariati
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Meiwand Bedar
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Xiaoyan Ren
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 91343, USA
| | - Shahrzad Moghadam
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Kelly X. Huang
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Wei Chen
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Youngnam Kang
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Dean T. Yamaguchi
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 91343, USA
| | - Justine C. Lee
- Division of Plastic & Reconstructive Surgery, University of California, Los Angeles David Geffen School of Medicine, Los Angeles, CA, 90095, USA
- Research Service, Greater Los Angeles VA Healthcare System, Los Angeles, CA, 91343, USA
- Department of Orthopaedic Surgery, Los Angeles, CA, 90095, USA
- UCLA Molecular Biology Institute, Los Angeles, CA, 90095, USA
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6
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Nile M, Folwaczny M, Wichelhaus A, Baumert U, Janjic Rankovic M. Fluid flow shear stress and tissue remodeling-an orthodontic perspective: evidence synthesis and differential gene expression network analysis. Front Bioeng Biotechnol 2023; 11:1256825. [PMID: 37795174 PMCID: PMC10545883 DOI: 10.3389/fbioe.2023.1256825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/28/2023] [Indexed: 10/06/2023] Open
Abstract
Introduction: This study aimed to identify and analyze in vitro studies investigating the biological effect of fluid-flow shear stress (FSS) on cells found in the periodontal ligament and bone tissue. Method: We followed the PRISMA guideline for systematic reviews. A PubMed search strategy was developed, studies were selected according to predefined eligibility criteria, and the risk of bias was assessed. Relevant data related to cell source, applied FSS, and locus-specific expression were extracted. Based on this evidence synthesis and, as an original part of this work, analysis of differential gene expression using over-representation and network-analysis was performed. Five relevant publicly available gene expression datasets were analyzed using gene set enrichment analysis (GSEA). Result: A total of 6,974 articles were identified. Titles and abstracts were screened, and 218 articles were selected for full-text assessment. Finally, 120 articles were included in this study. Sample size determination and statistical analysis related to methodological quality and the ethical statement item in reporting quality were most frequently identified as high risk of bias. The analyzed studies mostly used custom-made fluid-flow apparatuses (61.7%). FSS was most frequently applied for 0.5 h, 1 h, or 2 h, whereas FSS magnitudes ranged from 6 to 20 dyn/cm2 depending on cell type and flow profile. Fluid-flow frequencies of 1 Hz in human cells and 1 and 5 Hz in mouse cells were mostly applied. FSS upregulated genes/metabolites responsible for tissue formation (AKT1, alkaline phosphatase, BGLAP, BMP2, Ca2+, COL1A1, CTNNB1, GJA1, MAPK1/MAPK3, PDPN, RUNX2, SPP1, TNFRSF11B, VEGFA, WNT3A) and inflammation (nitric oxide, PGE-2, PGI-2, PTGS1, PTGS2). Protein-protein interaction networks were constructed and analyzed using over-representation analysis and GSEA to identify shared signaling pathways. Conclusion: To our knowledge, this is the first review giving a comprehensive overview and discussion of methodological technical details regarding fluid flow application in 2D cell culture in vitro experimental conditions. Therefore, it is not only providing valuable information about cellular molecular events and their quantitative and qualitative analysis, but also confirming the reproducibility of previously published results.
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Affiliation(s)
- Mustafa Nile
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
| | - Matthias Folwaczny
- Department of Conservative Dentistry and Periodontology, LMU University Hospital, LMU Munich, Munich, Germany
| | - Andrea Wichelhaus
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
| | - Uwe Baumert
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
| | - Mila Janjic Rankovic
- Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany
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Lara-Castillo N, Masunaga J, Brotto L, Vallejo JA, Javid K, Wacker MJ, Brotto M, Bonewald LF, Johnson ML. Muscle secreted factors enhance activation of the PI3K/Akt and β-catenin pathways in murine osteocytes. Bone 2023; 174:116833. [PMID: 37385426 PMCID: PMC10926931 DOI: 10.1016/j.bone.2023.116833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/19/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
Skeletal muscle and bone interact at the level of mechanical loading through the application of force by muscles to the skeleton and more recently focus has been placed on molecular/biochemical coupling of these two tissues. We sought to determine if muscle and muscle-derived factors were essential to the osteocyte response to loading. Botox® induced muscle paralysis was used to investigate the role of muscle contraction during in vivo tibia compression loading. 5-6 month-old female TOPGAL mice had their right hindlimb muscles surrounding the tibia injected with either BOTOX® or saline. At four days post injections when muscle paralysis peaked, the right tibia was subjected to a single session of in vivo compression loading at ∼2600 με. At 24 h post-load we observed a 2.5-fold increase in β-catenin signaling in osteocytes in the tibias of the saline injected mice, whereas loading of tibias from Botox® injected mice failed to active β-catenin signaling in osteocytes. This suggests that active muscle contraction produces a factor(s) that is necessary for or conditions the osteocyte's ability to respond to load. To further investigate the role of muscle derived factors, MLO-Y4 osteocyte-like cells and a luciferase based β-catenin reporter (TOPflash-MLO-Y4) cell line we developed were treated with conditioned media (CM) from C2C12 myoblasts (MB) and myotubes (MT) and ex vivo contracted Extensor Digitorum Longus (EDL) and Soleus (Sol) muscles under static or loading conditions using fluid flow shear stress (FFSS). 10 % C2C12 myotube CM, but not myoblast or NIH3T3 fibroblast cells CM, induced a rapid activation of the Akt signaling pathway, peaking at 15 min and returning to baseline by 1-2 h under static conditions. FFSS applied to MLO-Y4 cells for 2 h in the presence of 10 % MT-CM resulted in a 6-8 fold increase in pAkt compared to a 3-4 fold increase under control or when exposed to 10 % MB-CM. A similar response was observed in the presence of 10 % EDL-CM, but not in the presence of 10 % Sol-CM. TOPflash-MLO-Y4 cells were treated with 10 ng/ml Wnt3a in the presence or absence of MT-CM. While MT-CM resulted in a 2-fold activation and Wnt3a produced a 10-fold activation, the combination of MT-CM + Wnt3a resulted in a 25-fold activation of β-catenin signaling, implying a synergistic effect of factors in MT-CM with Wnt3a. These data provide clear evidence that specific muscles and myotubes produce factors that alter important signaling pathways involved in the response of osteocytes to mechanical load. These data strongly suggest that beyond mechanical loading there is a molecular coupling of muscle and bone.
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Affiliation(s)
- N Lara-Castillo
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America.
| | - J Masunaga
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America
| | - L Brotto
- Bone-Muscle Research Center, College of Nursing and Health Innovation, University of Texas at Arlington, 411 S. Nedderman Dr, Arlington, TX 76019, United States of America
| | - J A Vallejo
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America; Department of Biomedical Sciences, UMKC School of Medicine, 2411 Holmes, Kansas City, MO 64108, United States of America
| | - K Javid
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America
| | - M J Wacker
- Department of Biomedical Sciences, UMKC School of Medicine, 2411 Holmes, Kansas City, MO 64108, United States of America
| | - M Brotto
- Department of Biomedical Sciences, UMKC School of Medicine, 2411 Holmes, Kansas City, MO 64108, United States of America
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America; Indiana Center for Musculoskeletal Health, Barnhill Drive, Indianapolis, IN 46202, United States of America
| | - M L Johnson
- Department of Oral and Craniofacial Sciences, UMKC School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, United States of America
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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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9
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E. Worton L, Srinivasan S, Threet D, Ausk BJ, Huber P, Y. Kwon R, Bain SD, Gross TS, M. Gardiner E. Beta 2 Adrenergic Receptor Selective Antagonist Enhances Mechanically Stimulated Bone Anabolism in Aged Mice. JBMR Plus 2022; 7:e10712. [PMID: 36751418 PMCID: PMC9893264 DOI: 10.1002/jbm4.10712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/25/2022] [Accepted: 11/06/2022] [Indexed: 12/14/2022] Open
Abstract
The anabolic response of aged bone to skeletal loading is typically poor. Efforts to improve mechanotransduction in aged bone have met with limited success. This study investigated whether the bone response to direct skeletal loading is improved by reducing sympathetic suppression of osteoblastic bone formation via β2AR. To test this possibility, we treated aged wild-type C57BL/6 mice with a selective β2AR antagonist, butaxamine (Butax), before each of nine bouts of cantilever bending of the right tibia. Midshaft periosteal bone formation was assessed by dynamic histomorphometry of loaded and contralateral tibias. Butax treatment did not alter osteoblast activity of contralateral tibias. Loading alone induced a modest but significant osteogenic response. However, when loading was combined with Butax pretreatment, the anabolic response was significantly elevated compared with loading preceded by saline injection. Subsequent studies in osteoblastic cultures revealed complex negative interactions between adrenergic and mechanically induced intracellular signaling. Activation of β2AR by treatment with the β1, β2-agonist isoproterenol (ISO) before fluid flow exposure diminished mechanically stimulated ERK1/2 phosphorylation in primary bone cell outgrowth cultures and AKT phosphorylation in MC3T3-E1 pre-osteoblast cultures. Expression of mechanosensitive Fos and Ptgs2 genes was enhanced with ISO treatment and reduced with flow in both MC3T3-E1 and primary cultures. Finally, co-treatment of MC3T3-E1 cells with Butax reversed these ISO effects, confirming a critical role for β2AR in these responses. In combination, these results demonstrate that selective inhibition of β2AR is sufficient to enhance the anabolic response of the aged skeleton to loading, potentially via direct effects upon osteoblasts. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Leah E. Worton
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Sundar Srinivasan
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - DeWayne Threet
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Brandon J. Ausk
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Phillipe Huber
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Ronald Y. Kwon
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Steven D. Bain
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Ted S. Gross
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
| | - Edith M. Gardiner
- Department of Orthopaedics & Sports MedicineUniversity of WashingtonSeattleWAUSA
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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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11
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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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12
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Choi JUA, Kijas AW, Lauko J, Rowan AE. The Mechanosensory Role of Osteocytes and Implications for Bone Health and Disease States. Front Cell Dev Biol 2022; 9:770143. [PMID: 35265628 PMCID: PMC8900535 DOI: 10.3389/fcell.2021.770143] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/13/2021] [Indexed: 12/14/2022] Open
Abstract
Bone homeostasis is a dynamic equilibrium between bone-forming osteoblasts and bone-resorbing osteoclasts. This process is primarily controlled by the most abundant and mechanosensitive bone cells, osteocytes, that reside individually, within chambers of porous hydroxyapatite bone matrix. Recent studies have unveiled additional functional roles for osteocytes in directly contributing to local matrix regulation as well as systemic roles through endocrine functions by communicating with distant organs such as the kidney. Osteocyte function is governed largely by both biochemical signaling and the mechanical stimuli exerted on bone. Mechanical stimulation is required to maintain bone health whilst aging and reduced level of loading are known to result in bone loss. To date, both in vivo and in vitro approaches have been established to answer important questions such as the effect of mechanical stimuli, the mechanosensors involved, and the mechanosensitive signaling pathways in osteocytes. However, our understanding of osteocyte mechanotransduction has been limited due to the technical challenges of working with these cells since they are individually embedded within the hard hydroxyapatite bone matrix. This review highlights the current knowledge of the osteocyte functional role in maintaining bone health and the key regulatory pathways of these mechanosensitive cells. Finally, we elaborate on the current therapeutic opportunities offered by existing treatments and the potential for targeting osteocyte-directed signaling.
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Affiliation(s)
- Jung Un Ally Choi
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Amanda W Kijas
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Jan Lauko
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Alan E Rowan
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
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13
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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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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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Steppe L, Krüger BT, Tschaffon MEA, Fischer V, Tuckermann J, Ignatius A, Haffner-Luntzer M. Estrogen Receptor α Signaling in Osteoblasts is Required for Mechanotransduction in Bone Fracture Healing. Front Bioeng Biotechnol 2021; 9:782355. [PMID: 34950644 PMCID: PMC8689144 DOI: 10.3389/fbioe.2021.782355] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022] Open
Abstract
Biomechanical stimulation by whole-body low-magnitude high-frequency vibration (LMHFV) has demonstrated to provoke anabolic effects on bone metabolism in both non-osteoporotic and osteoporotic animals and humans. However, preclinical studies reported that vibration improved fracture healing and bone formation in osteoporotic, ovariectomized (OVX) mice representing an estrogen-deficient hormonal status, but impaired bone regeneration in skeletally healthy non-OVX mice. These effects were abolished in general estrogen receptor α (ERα)-knockout (KO) mice. However, it remains to be elucidated which cell types in the fracture callus are targeted by LMHFV during bone healing. To answer this question, we generated osteoblast lineage-specific ERα-KO mice that were subjected to ovariectomy, femur osteotomy and subsequent vibration. We found that the ERα specifically on osteoblastic lineage cells facilitated the vibration-induced effects on fracture healing, because in osteoblast lineage-specific ERα-KO (ERαfl/fl; Runx2Cre) mice the negative effects in non-OVX mice were abolished, whereas the positive effects of vibration in OVX mice were reversed. To gain greater mechanistic insights, the influence of vibration on murine and human osteogenic cells was investigated in vitro by whole genome array analysis and qPCR. The results suggested that particularly canonical WNT and Cox2/PGE2 signaling is involved in the mechanotransduction of LMHFV under estrogen-deficient conditions. In conclusion, our study demonstrates a critical role of the osteoblast lineage-specific ERα in LMHFV-induced effects on fracture healing and provides further insights into the molecular mechanism behind these effects.
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Affiliation(s)
- Lena Steppe
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | - Benjamin Thilo Krüger
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | | | - Verena Fischer
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | - Jan Tuckermann
- Institute of Comparative Molecular Endocrinology (CME), Ulm University, Ulm, Germany
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
| | - Melanie Haffner-Luntzer
- Institute of Orthopedic Research and Biomechanics, University Medical Center Ulm, Ulm, Germany
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16
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Zheng QL, Zhu HY, Xu X, Chu SF, Cui LY, Dong YX, Liu YJ, Zhan JH, Wang ZZ, Chen NH. Korean red ginseng alleviate depressive disorder by improving astrocyte gap junction function. JOURNAL OF ETHNOPHARMACOLOGY 2021; 281:114466. [PMID: 34332064 DOI: 10.1016/j.jep.2021.114466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 06/28/2021] [Accepted: 07/25/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Korean red ginseng (KRG), a processed product of Panax ginseng C. A. Mey, show significant anti-depressive effect in clinic. However, its mechanism is still unclear. AIM OF THE STUDY Gap junction intercellular communication (GJIC) dysfunction is a potential pathogenesis of depression. Therefore, this study's objective is to investigate whether the antidepressant effect of KRG is related to GJIC. MATERIALS AND METHODS Rat were restraint 8 h every day for 28 consecutive days to prepare depression models, and meanwhile, rats were intragastrically administrated with normal saline, KRG solutions (25, 50 or 100 mg/kg) or fluoxetine (10 mg/kg) 1 h before stress. The behavioral performance was determined by forced swimming test, sucrose preference test and open field test. GJIC was determined by the Lucifer yellow (LY) diffusion distance in prelimb cortex (PLC). In addition, the level of Cx43, one of executors of GJIC, was tested by Western blot. To find out the protective effect of KRG against GJIC dysfunction directly, rats were intracranially injected with carbenoxolone (CBX, blocker of GJIC), and meanwhile normal saline, KRG (100 mg/kg) or fluoxetine (10 mg/kg) was administered daily. The behavioral performance of these rats was detected, and the LY localization injection PLC area was used to detect the gap junction function. RESULTS Chronic resistant stress (CRS) induced depressive symptoms, as manifested by prolonged immobility time in forced swimming test and decreased sucrose consumption ratio. Administration of KRG alleviated these depressive symptoms significantly. GJIC determination showed that KRG improved the LY diffusion and increased Cx43 level in prefrontal cortex (PFC) significantly, indicated that GJIC dysfunction was alleviated by the treatment of KRG. However, the astrocytes number was also increased by the treatment of KRG, which maybe alleviate depression-like symptoms by increasing the number of astrocytes rather than improving GJIC. Injection of CBX produced depressive symptoms and GJIC dysfunction, as manifested by decreased sucrose consumption ratio and prolonged immobility time in forced swimming test, but no astrocytes number changes, KRG also reversed depressive symptoms and GJIC dysfunction, suggested that the improvement of depressive-like symptoms was improved by GJIC. CONCLUSIONS KRG alleviate depressive disorder by improving astrocytic gap junction function.
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Affiliation(s)
- Qing-Lian Zheng
- Institute for Brain Research and Rehabilitation (IBRR), South China Normal University (SCNU), Guangzhou, 510631, China.
| | - Hao-Yu Zhu
- 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.
| | - Xin Xu
- Institute for Brain Research and Rehabilitation (IBRR), South China Normal University (SCNU), Guangzhou, 510631, China.
| | - Shi-Feng Chu
- 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.
| | - Li-Yuan Cui
- 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.
| | - Yi-Xiao Dong
- 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.
| | - Ying-Jiao Liu
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208 Hunan, China.
| | - Jia-Hong Zhan
- DME Center, Clinical Pharmacology Institute, Guangzhou University of Chinese Medicine, Guangzhou, 510405, 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.
| | - Nai-Hong Chen
- Institute for Brain Research and Rehabilitation (IBRR), South China Normal University (SCNU), Guangzhou, 510631, China; 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; Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208 Hunan, China; DME Center, Clinical Pharmacology Institute, Guangzhou University of Chinese Medicine, Guangzhou, 510405, China.
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17
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Garg P, Strigini M, Peurière L, Vico L, Iandolo D. The Skeletal Cellular and Molecular Underpinning of the Murine Hindlimb Unloading Model. Front Physiol 2021; 12:749464. [PMID: 34737712 PMCID: PMC8562483 DOI: 10.3389/fphys.2021.749464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/23/2021] [Indexed: 01/08/2023] Open
Abstract
Bone adaptation to spaceflight results in bone loss at weight bearing sites following the absence of the stimulus represented by ground force. The rodent hindlimb unloading model was designed to mimic the loss of mechanical loading experienced by astronauts in spaceflight to better understand the mechanisms causing this disuse-induced bone loss. The model has also been largely adopted to study disuse osteopenia and therefore to test drugs for its treatment. Loss of trabecular and cortical bone is observed in long bones of hindlimbs in tail-suspended rodents. Over the years, osteocytes have been shown to play a key role in sensing mechanical stress/stimulus via the ECM-integrin-cytoskeletal axis and to respond to it by regulating different cytokines such as SOST and RANKL. Colder experimental environments (~20-22°C) below thermoneutral temperatures (~28-32°C) exacerbate bone loss. Hence, it is important to consider the role of environmental temperatures on the experimental outcomes. We provide insights into the cellular and molecular pathways that have been shown to play a role in the hindlimb unloading and recommendations to minimize the effects of conditions that we refer to as confounding factors.
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Affiliation(s)
- Priyanka Garg
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Maura Strigini
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Laura Peurière
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Laurence Vico
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
| | - Donata Iandolo
- INSERM, U1059 Sainbiose, Université Jean Monnet, Mines Saint-Étienne, Université de Lyon, Saint-Étienne, France
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18
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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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19
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Gardinier JD. The Diminishing Returns of Mechanical Loading and Potential Mechanisms that Desensitize Osteocytes. Curr Osteoporos Rep 2021; 19:436-443. [PMID: 34216359 PMCID: PMC9306018 DOI: 10.1007/s11914-021-00693-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/27/2021] [Indexed: 11/30/2022]
Abstract
Adaptation to mechanical loading is critical to maintaining bone mass and offers therapeutic potential to preventing age-related bone loss and osteoporosis. However, increasing the duration of loading is met with "diminishing returns" as the anabolic response quickly becomes saturated. As a result, the anabolic response to daily activities and repetitive bouts of loading is limited by the underlying mechanisms that desensitize and render bone unresponsive at the cellular level. Osteocytes are the primary cells that respond to skeletal loading and facilitate the overall anabolic response. Although many of osteocytes' signaling mechanisms activated in response to loading are considered anabolic in nature, several of them can also render osteocytes insensitive to further stimuli and thereby creating a negative feedback loop that limits osteocytes' overall response. The purpose of this review is to examine the potential mechanisms that may contribute to the loss of mechanosensitivity. In particular, we examined the inactivation/desensitization of ion channels and signaling molecules along with the potential role of endocytosis and cytoskeletal reorganization. The significance in defining the negative feedback loop is the potential to identify unique targets for enabling osteocytes to maintain their sensitivity. In doing so, we can begin to cultivate new strategies that capitalize on the anabolic nature of daily activities that repeatedly load the skeleton.
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Srivastava T, Heruth DP, Duncan RS, Rezaiekhaligh MH, Garola RE, Priya L, Zhou J, Boinpelly VC, Novak J, Ali MF, Joshi T, Alon US, Jiang Y, McCarthy ET, Savin VJ, Sharma R, Johnson ML, Sharma M. Transcription Factor β-Catenin Plays a Key Role in Fluid Flow Shear Stress-Mediated Glomerular Injury in Solitary Kidney. Cells 2021; 10:cells10051253. [PMID: 34069476 PMCID: PMC8159099 DOI: 10.3390/cells10051253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/06/2021] [Accepted: 05/14/2021] [Indexed: 01/21/2023] Open
Abstract
Increased fluid flow shear stress (FFSS) in solitary kidney alters podocyte function in vivo. FFSS-treated cultured podocytes show upregulated AKT-GSK3β-β-catenin signaling. The present study was undertaken to confirm (i) the activation of β-catenin signaling in podocytes in vivo using unilaterally nephrectomized (UNX) TOPGAL mice with the β-galactosidase reporter gene for β-catenin activation, (ii) β-catenin translocation in FFSS-treated mouse podocytes, and (iii) β-catenin signaling using publicly available data from UNX mice. The UNX of TOPGAL mice resulted in glomerular hypertrophy and increased the mesangial matrix consistent with hemodynamic adaptation. Uninephrectomized TOPGAL mice showed an increased β-galactosidase expression at 4 weeks but not at 12 weeks, as assessed using immunofluorescence microscopy (p < 0.001 at 4 weeks; p = 0.16 at 12 weeks) and X-gal staining (p = 0.008 at 4 weeks; p = 0.65 at 12 weeks). Immunofluorescence microscopy showed a significant increase in phospho-β-catenin (Ser552, p = 0.005) at 4 weeks but not at 12 weeks (p = 0.935) following UNX, and the levels of phospho-β-catenin (Ser675) did not change. In vitro FFSS caused a sustained increase in the nuclear translocation of phospho-β-catenin (Ser552) but not phospho-β-catenin (Ser675) in podocytes. The bioinformatic analysis of the GEO dataset, #GSE53996, also identified β-catenin as a key upstream regulator. We conclude that transcription factor β-catenin mediates FFSS-induced podocyte (glomerular) injury in solitary kidney.
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Affiliation(s)
- Tarak Srivastava
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA; (M.H.R.); (L.P.); (M.F.A.); (U.S.A.)
- Midwest Veterans’ Biomedical Research Foundation (MVBRF), Kansas City, MO 64128, USA; (J.Z.); (V.C.B.); (M.S.)
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri at Kansas City, Kansas City, MO 64108, USA;
- Correspondence: ; Tel.: +1-816-234-3010; Fax: +1-816-302-9919
| | - Daniel P. Heruth
- Children’s Mercy Research Institute, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA;
| | - R. Scott Duncan
- School of Biological Sciences, University of Missouri at Kansas City, Kansas City, MO 64108, USA;
| | - Mohammad H. Rezaiekhaligh
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA; (M.H.R.); (L.P.); (M.F.A.); (U.S.A.)
| | - Robert E. Garola
- Department of Pathology and Laboratory Medicine, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA;
| | - Lakshmi Priya
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA; (M.H.R.); (L.P.); (M.F.A.); (U.S.A.)
| | - Jianping Zhou
- Midwest Veterans’ Biomedical Research Foundation (MVBRF), Kansas City, MO 64128, USA; (J.Z.); (V.C.B.); (M.S.)
- Kansas City VA Medical Center, Kansas City, MO 64128, USA; (V.J.S.); (R.S.)
| | - Varun C. Boinpelly
- Midwest Veterans’ Biomedical Research Foundation (MVBRF), Kansas City, MO 64128, USA; (J.Z.); (V.C.B.); (M.S.)
- Kansas City VA Medical Center, Kansas City, MO 64128, USA; (V.J.S.); (R.S.)
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35487, USA;
| | - Mohammed Farhan Ali
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA; (M.H.R.); (L.P.); (M.F.A.); (U.S.A.)
| | - Trupti Joshi
- Department of Health Management and Informatics, University of Missouri, Columbia, MO 65211, USA;
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO 65211, USA;
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- MU Data Science and Informatics Institute, University of Missouri, Columbia, MO 65211, USA
| | - Uri S. Alon
- Section of Nephrology, Children’s Mercy Hospital and University of Missouri at Kansas City, Kansas City, MO 64108, USA; (M.H.R.); (L.P.); (M.F.A.); (U.S.A.)
| | - Yuexu Jiang
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO 65211, USA;
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Ellen T. McCarthy
- Department of Internal Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Virginia J. Savin
- Kansas City VA Medical Center, Kansas City, MO 64128, USA; (V.J.S.); (R.S.)
| | - Ram Sharma
- Kansas City VA Medical Center, Kansas City, MO 64128, USA; (V.J.S.); (R.S.)
| | - Mark L. Johnson
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri at Kansas City, Kansas City, MO 64108, USA;
| | - Mukut Sharma
- Midwest Veterans’ Biomedical Research Foundation (MVBRF), Kansas City, MO 64128, USA; (J.Z.); (V.C.B.); (M.S.)
- Kansas City VA Medical Center, Kansas City, MO 64128, USA; (V.J.S.); (R.S.)
- Department of Internal Medicine, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA;
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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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22
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Zhao X, Alqwbani M, Luo Y, Chen C, A G, Wei Y, Li D, Wang Q, Tian M, Kang P. Glucocorticoids decreased Cx43 expression in osteonecrosis of femoral head: The effect on proliferation and osteogenic differentiation of rat BMSCs. J Cell Mol Med 2020; 25:484-498. [PMID: 33205619 PMCID: PMC7810924 DOI: 10.1111/jcmm.16103] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/10/2020] [Accepted: 11/01/2020] [Indexed: 02/05/2023] Open
Abstract
Glucocorticoid (GC)‐induced osteonecrosis of the femoral head (GC‐ONFH) is considered as one of the most serious side effects of long‐term or over‐dose steroid therapy. However, the underlying cause mechanisms are still not fully investigated. We firstly established a rat model of GC‐ONFH and injected lipopolysaccharide (LPS) and methylprednisolone (MPS). We found that the expressions of Cx43, Runx2, ALP and COLⅠ were more decreased than the normal group. Secondly, the isolated rat bone marrow stem cells (BMSCs) were treated with dexamethasone (Dex) in vitro, and the expressions of Cx43, Runx2, ALP and COLⅠ were decreased significantly. Moreover, the results of immunofluorescence staining, alizarin red staining, EdU assay and CCK8 showed that the osteogenic differentiation and the proliferation capacity of BMSCs were decreased after induced by Dex. A plasmid of lentivirus‐mediated Cx43 (Lv‐Cx43) gene overexpression was established to investigate the function of Cx43 in BMSCs under the Dex treatment. Findings demonstrated that the proliferation and osteogenic differentiation abilities were enhanced after Lv‐Cx43 transfected to BMSCs, and these beneficial effects of Lv‐Cx43 were significantly blocked when PD988059 (an inhibitor of ERK1/2) was used. In conclusion, the overexpression of Cx43 could promote the proliferation and osteogenic differentiation of BMSCs via activating the ERK1/2 signalling pathway, which provide a basic evidence for further study on the detailed function of Cx43 in GC‐ONFH.
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Affiliation(s)
- Xin Zhao
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Mohammed Alqwbani
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yue Luo
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Changjun Chen
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Ge A
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Wei
- Neurosurgery Research Laboratory, West China Hospital, Sichuan University, Chengdu, China
| | - Donghai Li
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Qiuru Wang
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Meng Tian
- Neurosurgery Research Laboratory, West China Hospital, Sichuan University, Chengdu, China
| | - Pengde Kang
- Department of Orthopaedics Surgery, West China Hospital, Sichuan University, Chengdu, China
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23
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Targeting Mechanotransduction in Osteosarcoma: A Comparative Oncology Perspective. Int J Mol Sci 2020; 21:ijms21207595. [PMID: 33066583 PMCID: PMC7589883 DOI: 10.3390/ijms21207595] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Mechanotransduction is the process in which cells can convert extracellular mechanical stimuli into biochemical changes within a cell. While this a normal process for physiological development and function in many organ systems, tumour cells can exploit this process to promote tumour progression. Here we summarise the current state of knowledge of mechanotransduction in osteosarcoma (OSA), the most common primary bone tumour, referencing both human and canine models and other similar mesenchymal malignancies (e.g., Ewing sarcoma). Specifically, we discuss the mechanical properties of OSA cells, the pathways that these cells utilise to respond to external mechanical cues, and mechanotransduction-targeting strategies tested in OSA so far. We point out gaps in the literature and propose avenues to address them. Understanding how the physical microenvironment influences cell signalling and behaviour will lead to the improved design of strategies to target the mechanical vulnerabilities of OSA cells.
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Abstract
Bone is one of the most highly adaptive tissues in the body, possessing the capability to alter its morphology and function in response to stimuli in its surrounding environment. The ability of bone to sense and convert external mechanical stimuli into a biochemical response, which ultimately alters the phenotype and function of the cell, is described as mechanotransduction. This review aims to describe the fundamental physiology and biomechanisms that occur to induce osteogenic adaptation of a cell following application of a physical stimulus. Considerable developments have been made in recent years in our understanding of how cells orchestrate this complex interplay of processes, and have become the focus of research in osteogenesis. We will discuss current areas of preclinical and clinical research exploring the harnessing of mechanotransductive properties of cells and applying them therapeutically, both in the context of fracture healing and de novo bone formation in situations such as nonunion. Cite this article: Bone Joint Res 2019;9(1):1–14.
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25
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Abstract
Intercalated discs (ICDs) are highly orchestrated structures that connect neighboring cardiomyocytes in the heart. Three major complexes are distinguished in ICD: desmosome, adherens junction (AJ), and gap junction (GJ). Desmosomes are major cell adhesion junctions that anchor cell membrane to the intermediate filament network; AJs connect the actin cytoskeleton of adjacent cells; and gap junctions metabolically and electrically connect the cytoplasm of adjacent cardiomyocytes. All these complexes work as a single unit, the so-called area composita, interdependently rather than individually. Mutation or altered expression of ICD proteins results in various cardiac diseases, such as ARVC (arrhythmogenic right ventricular cardiomyopathy), dilated cardiomyopathy, and hypotrophy cardiomyopathy, eventually leading to heart failure. In this article, we first review the recent findings on the structural organization of ICD and their functions and then focus on the recent advances in molecular pathogenesis of the ICD-related heart diseases, which include two major areas: i) the ICD gene mutations in cardiac diseases, and ii) the involvement of ICD proteins in signal transduction pathways leading to myocardium remodeling and eventual heart failure. These major ICD-related signaling pathways include Wnt/β-catenin pathway, p38 MAPK cascade, Rho-dependent serum response factor (SRF) signaling, calcineurin/NFAT signaling, Hippo kinase cascade, etc., which are differentially regulated in pathological conditions.
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26
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Wang T, Yu X, He C. Pro-inflammatory Cytokines: Cellular and Molecular Drug Targets for Glucocorticoid-induced-osteoporosis via Osteocyte. Curr Drug Targets 2020; 20:1-15. [PMID: 29618305 DOI: 10.2174/1389450119666180405094046] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/11/2018] [Accepted: 03/21/2018] [Indexed: 02/08/2023]
Abstract
Glucocorticoids are widely used to treat varieties of allergic and autoimmune diseases, however, long-term application results in glucocorticoid-induced osteoporosis (GIOP). Inflammatory cytokines: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) play important regulatory roles in bone metabolism, but their roles in GIOP remain largely unknown. Osteocytes can modulate the formation and function of both osteoblasts and osteoclasts, directly via gap junctions, or indirectly by transferring molecule signaling. Apoptotic osteocytes release RANKL, HMGB1 and pro-inflammatory cytokines to stimulate osteoclastogenesis. Moreover, osteocytes can secrete FGF23 to regulate bone metabolism. Exposure to high levels of GCs can drive osteocyte apoptosis and influence gap junctions, leading to bone loss. GCs treatment is regarded to produce more FGF23 to inhibit bone mineralization. GCs also disrupt the vascular to decrease osteocyte feasibility and mineral appositional rate, resulting in a decline in bone strength. Apoptotic bodies from osteocytes induced by GCs treatment can enhance production of TNF-α and IL-6. On the other hand, TNF-α and IL-6 show synergistic effects by altering osteocytes signaling towards osteoclasts and osteoblasts. In addition, TNF-α can induce osteocyte apoptosis and attribute to a worsened bone quality in GCs. IL-6 and osteocytes may interact with each other. Therefore, we hypothesize that GCs regulate osteocyteogenesis through TNF-α and IL-6, which are highly expressed around osteocyte undergoing apoptosis. In the present review, we summarized the roles of osteocytes in regulating osteoblasts and osteoclasts. Furthermore, the mechanism of GCs altered relationship between osteocytes and osteoblasts/osteoclasts. In addition, we discussed the roles of TNF-α and IL-6 in GIOP by modulating osteocytes. Lastly, we discussed the possibility of using pro-inflammatory signaling pathway as therapeutic targets to develop drugs for GIOP.
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Affiliation(s)
- Tiantian Wang
- Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, China
| | - Chengqi He
- Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
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27
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Gregory M, Cyr DG. Effects of prostaglandin E2 on gap junction protein alpha 1 in the rat epididymis. Biol Reprod 2020; 100:123-132. [PMID: 30060123 DOI: 10.1093/biolre/ioy171] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 07/25/2018] [Indexed: 12/20/2022] Open
Abstract
Gap junctions are responsible for intercellular communication. In the adult mammalian epididymis, gap junction protein alpha 1 (GJA1) is localized between basal and either principal or clear cells. GJA1 levels and localization change during the differentiation of basal cells. The present objective was to determine the role of basal cells and prostaglandin E2 (PGE2) on GJA1 in the rat epididymis. Prior to basal cell differentiation, GJA1 is colocalized with TJP1 at the apical lateral margins between adjacent epithelial cells. When basal cells are present, GJA1 becomes associated between basal and principal cells, where it is primarily immunolocalized until adulthood. Basal cells express TP63, differentiate from epithelial cells, and produce prostaglandin-endoperoxide synthase 1 by 21 days of age. Prior to day 21, GJA1and TP63 are not strongly associated at the apical region. However, by day 28, TP63-positive basal cells migrate to the base of the epithelium, and also express GJA1. To assess effects of PGE2 on GJA1, rat caput epididymal (RCE) cells were exposed to PGE2 (50 μM) for 3 h. PGE2 increased levels of Gja1 mRNA in RCE cells, while levels of Gjb1, Gjb2, Gjb4, and GjB5 were unaltered. Furthermore, PGE2 increased protein levels of GJA1, phospho-GJA1, phospho-AKT, CTNNB1, and phospho-CTNNB1. Total AKT and the tight junction protein claudin1 were also not altered by PGE2. Data suggest that development of the epididymal epithelium and differentiation of epididymal basal cells regulate the targeting of GJA1, and that this appears to be mediated by PGE2.
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Affiliation(s)
- Mary Gregory
- Laboratory for Reproductive Toxicology, INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada
| | - Daniel G Cyr
- Laboratory for Reproductive Toxicology, INRS-Institut Armand-Frappier, University of Quebec, Laval, Quebec, Canada
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28
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Nguyen J, Massoumi R, Alliston T. CYLD, a mechanosensitive deubiquitinase, regulates TGFβ signaling in load-induced bone formation. Bone 2020; 131:115148. [PMID: 31715338 PMCID: PMC7032548 DOI: 10.1016/j.bone.2019.115148] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 12/21/2022]
Abstract
Many signaling pathways involved in bone homeostasis also participate in the anabolic response of bone to mechanical loading. For example, TGFβ signaling coordinates the maintenance of bone mass and bone quality through its effects on osteoblasts, osteoclasts, and osteocytes. TGFβ signaling is also essential for the mechanosensitive formation of new bone. However, the mechanosensitive mechanisms controlling TGFβ signaling in osteocytes remain to be determined, particularly those that integrate TGFβ signaling with other early responses to mechanical stimulation. Here, we used an in vivo mouse hindlimb loading model to identify mechanosensitive molecules in the TGFβ pathway, and MLO-Y4 cells to evaluate their interactions with the prostaglandin E2 (PGE2) pathway, which is well-known for its rapid response to mechanical stimulation and its role in bone anabolism. Although mRNA levels for several TGFβ ligands, receptors, and effectors were unchanged, the level of phosphorylated Smad2/3 (pSmad2/3) was reduced in tibial bone as early as 3 h after early mechanical stimulation. We found that PGE2 and its receptor, EP2, repress pSmad2/3 levels and transactivation of Serpine1 in osteocytes. PGE2 and EP2 control the level of pSmad2/3 through a proteasome-dependent mechanism that relies on the deubiquitinase CYLD. CYLD protein levels were also reduced in the tibiae within 3 h of mechanical loading. Using CYLD-deficient mice, we found that CYLD is required for the rapid load-mediated repression of pSmad2/3 and for load-induced bone formation. These data introduce CYLD as a mechanosensitive deubiquitinase that participates in the prostaglandin-dependent repression of TGFβ signaling in osteocytes.
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Affiliation(s)
- Jacqueline Nguyen
- Department of Orthopaedic Surgery, University of California San Francisco, 94143, USA; Graduate Program in Oral and Craniofacial Sciences, University of California San Francisco, 94143, USA
| | - Ramin Massoumi
- Department of Laboratory Medicine, Division of Translational Cancer Research, Lund University, Medicon Village, 22381, Sweden
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California San Francisco, 94143, USA; Graduate Program in Oral and Craniofacial Sciences, University of California San Francisco, 94143, USA.
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29
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Wang H, Li T, Wang X, Yin X, Zhao N, Zou S, Duan P, Bonewald LF. The role of sphingosine-1-phosphate signaling pathway in cementocyte mechanotransduction. Biochem Biophys Res Commun 2020; 523:595-601. [PMID: 31941604 DOI: 10.1016/j.bbrc.2020.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/02/2020] [Indexed: 02/08/2023]
Abstract
Iatrogenic external root resorption can become a serious pathological condition with clinical tooth movement. Little is known regarding how cementum responds to mechanical loading in contrast to bone, especially under compressive stress. In the field of bone biology, several studies have established the contribution of sphingosine-1-phosphate (S1P) signaling in bone remodeling, mechanical transduction and homeostasis. As osteocytes and cementocytes share similar morphological and functional characteristics, this study aimed to investigate the mechanotransduction ability of cementocytes and to explore the contribution of S1P signaling under compressive stress induced mechanotransduction. We found that compressive stress inhibited major S1P signaling and promoted the expression of anabolic factors in IDG-CM6 cells, a novel immortalized murine cementocyte cell line. By inhibiting S1P signaling, we verified that S1P signaling played a vital role in regulating the expression of the mechanotransduction factors prostaglandin E2 (PGE2) and β-catenin, as well as factors responsible for cementogenesis and cementoclastogenesis in IDG-CM6 cells. These results support the hypothesis that cementocytes act as key mechanically responsive cells in cementum, responding to compressive stress and directing local cementum metabolism.
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Affiliation(s)
- Han Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Tiancheng Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xin Wang
- Oral Diagnosis and Treatment Center, Aviation General Hospital, China Medical University, Beijing, China
| | - Xing Yin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Ning Zhao
- Department of Orthodontics, Shanghai Key Laboratory of Stomatology, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shujuan Zou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Peipei Duan
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
| | - Lynda F Bonewald
- Departments of Anatomy, Cell Biology & Physiology and Orthopaedic Surgery, Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States
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30
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Hou X, Khan MRA, Turmaine M, Thrasivoulou C, Becker DL, Ahmed A. Wnt signaling regulates cytosolic translocation of connexin 43. Am J Physiol Regul Integr Comp Physiol 2019; 317:R248-R261. [DOI: 10.1152/ajpregu.00268.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The availability of intracellular, stabilized β-catenin, a transcription factor coactivator, is tightly regulated; β-catenin is translocated into the nucleus in response to Wnt ligand binding to its cell membrane receptors. Here we show that Wnt signal activation in mammalian cells activates intracellular mobilization of connexin 43 (Cx43), which belongs to a gap junction protein family, a new target protein in response to extracellular Wnt signal activation. Transmission electron microscopy showed that the nuclear localization of Cx43 was increased by 8- to 10-fold in Wnt5A- and 9B-treated cells compared with controls; this Wnt-induced increase was negated in the cells where Cx43 and β-catenin were knocked down using shRNA. There was a significant ( P < 0.001) and concomitant depletion of the cell membrane and cytosolic signal of Cx43 in Wnt-treated cells with an increase in the nuclear signal for Cx43; this was more obvious in cells where β-catenin was knocked down using shRNA. Conversely, Cx43 knockdown resulted in increased β-catenin in the nucleus in the absence of Wnt activation. Coimmunoprecipitation of Cx43 and β-catenin proteins with a casein kinase (CKIδ) antibody showed that Cx43 interacts with β-catenin and may form part of the so-called destruction complex. Functionally, Wnt activation increased the rate of wound reepithelization in rat skin in vivo.
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Affiliation(s)
- Xiaoming Hou
- Prostate Cancer Research Centre, Division of Surgery, University College London, London, United Kingdom
- Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics, University College London, London, United Kingdom
| | - Mohammad R. A. Khan
- Prostate Cancer Research Centre at the Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London, United Kingdom
| | - Mark Turmaine
- Division of Biosciences, University College London, London, United Kingdom
| | - Christopher Thrasivoulou
- Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics, University College London, London, United Kingdom
| | - David L Becker
- Research Department of Cell and Developmental Biology, The Centre for Cell and Molecular Dynamics, University College London, London, United Kingdom
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
- Institute of Medical Biology, A*STAR, Singapore
| | - Aamir Ahmed
- Prostate Cancer Research Centre, Division of Surgery, University College London, London, United Kingdom
- Prostate Cancer Research Centre at the Centre for Stem Cells and Regenerative Medicine, King's College London, Guy's Hospital, London, United Kingdom
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Chen Y, Chen M, Xue T, Li G, Wang D, Shang P, Jiang JX, Xu H. Osteocytic connexin 43 channels affect fracture healing. J Cell Physiol 2019; 234:19824-19832. [PMID: 30980397 DOI: 10.1002/jcp.28581] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 02/24/2019] [Accepted: 03/05/2019] [Indexed: 12/27/2022]
Abstract
The cross-talk between cells is very critical for moving forward fracture healing in an orderly manner. Connexin (Cx) 43-formed gap junctions and hemichannels mediate the communication between adjacent cells and cells and extracellular environment. Loss of Cx43 in osteoblasts/osteocytes results in delayed fracture healing. For investigating the role of two channels in osteocytes in bone repair, two transgenic mouse models with Cx43 dominant negative mutants driven by a 10 kb-DMP1 promoter were generated: R76W (gap junctions are blocked, whereas hemichannels are promoted) and Δ130-136 (both gap junctions and hemichannels are blocked). R76W mice (promotion of hemichannels) showed a significant increase of new bone formation, whereas delayed osteoclastogenesis and healing was observed in Δ130-136 (impairment of gap junctions), but not in R76W mice (hemichannel promotion may recover the delay). These results suggest that gap junctions and hemichannels play some similar and cooperative roles in bone repair.
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Affiliation(s)
- Yunhe Chen
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Meng Chen
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Tong Xue
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Guobin Li
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Dongen Wang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Peng Shang
- Key Laboratory for Space Bioscience and Biotechnology, Research & Development Institute in Shenzhen, Northwestern Polytechnical UniversityShenzhen, Shenzhen, Guangdong, China
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas
| | - Huiyun Xu
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China.,Key Laboratory for Space Bioscience and Biotechnology, Research & Development Institute in Shenzhen, Northwestern Polytechnical UniversityShenzhen, Shenzhen, Guangdong, China.,Research Center of Special Environmental Biomechanics & Medical Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi, China
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PI3k and Stat3: Oncogenes that are Required for Gap Junctional, Intercellular Communication. Cancers (Basel) 2019; 11:cancers11020167. [PMID: 30717267 PMCID: PMC6406562 DOI: 10.3390/cancers11020167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/21/2019] [Accepted: 01/26/2019] [Indexed: 12/12/2022] Open
Abstract
Gap junctional, intercellular communication (GJIC) is interrupted in cells transformed by oncogenes such as activated Src. The Src effector, Ras, is required for this effect, so that Ras inhibition restores GJIC in Src-transformed cells. Interestingly, the inhibition of the Src effector phosphatidyl-inositol-3 kinase (PI3k) or Signal Transducer and Activator of Transcription-3 (Stat3) pathways does not restore GJIC. In the contrary, inhibition of PI3k or Stat3 in non-transformed rodent fibroblasts or epithelial cells or certain human lung carcinoma lines with extensive GJIC inhibits communication, while mutational activation of PI3k or Stat3 increases GJIC. Therefore, it appears that oncogenes such as activated Src have a dual role upon GJIC; acting as inhibitors of communication through the Ras pathway, and as activators through activation of PI3k or Stat3. In the presence of high Src activity the inhibitory functions prevail so that the net effect is gap junction closure. PI3k and Stat3 constitute potent survival signals, so that their inhibition in non-transformed cells triggers apoptosis which, in turn, has been independently demonstrated to suppress GJIC. The interruption of gap junctional communication would confine the apoptotic event to single cells and this might be essential for the maintenance of tissue integrity. We hypothesize that the GJIC activation by PI3k or Stat3 may be linked to their survival function.
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Parija S, Jandhyam H. Curcumin vasorelaxation in uterine artery of goat (Capra hircus) is mediated by differential activation of nitric oxide, prostaglandin I2, soluble guanylyl cyclase, and gap junction communication. Pharmacogn Mag 2019. [DOI: 10.4103/pm.pm_188_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Bhattacharya S, Gargiulo D, Iovine MK. Simplet-dependent regulation of β-catenin signaling influences skeletal patterning downstream of Cx43. Development 2018; 145:dev.166975. [PMID: 30377172 DOI: 10.1242/dev.166975] [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: 04/23/2018] [Accepted: 10/24/2018] [Indexed: 01/08/2023]
Abstract
The correct positioning of joints in the vertebrate skeleton is not well understood. Mutations in connexin43 (cx43) cause the short segment phenotype of the zebrafish short fin (sofb123 ) mutant. We have shown that Cx43 suppresses evx1 expression, a transcription factor required for joint formation. Here, we provide novel insights into how Cx43 influences evx1 transcription. First, we find that Simplet (Smp) knockdown recapitulates the sofb123 phenotypes of reduced regenerate length and reduced segment length, and we find evidence for synergy between cx43 and smp Moreover, knockdown of Smp increases the evx1 expression, similar to cx43 knockdown. Previous studies have shown that Smp is required for the nuclear localization of β-catenin. Indeed, β-catenin activity is required for segment length, and is reduced in both sofb123 mutants and following Smp knockdown in regenerating fins. We further show that blocking canonical Wnt signaling results in a synergistic reduction in segment length in sofb123 /+ heterozygotes. Together, our findings suggest that both Smp and β-catenin function in a common molecular pathway with cx43 to influence both evx1 expression and joint location.
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Affiliation(s)
| | - Domenic Gargiulo
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
| | - M Kathryn Iovine
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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Zhao F, Yan J, Zhao J, Shi B, Ye M, Huang X, Yu B, Lv B, Huang W. Effect of platelet-derived growth factor-BB on gap junction and connexin43 in rat penile corpus cavernosum smooth muscle cells. Andrologia 2018; 51:e13200. [PMID: 30467872 DOI: 10.1111/and.13200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 10/14/2018] [Accepted: 10/20/2018] [Indexed: 01/19/2023] Open
Abstract
We explored whether platelet-derived growth factor (PDGF)-BB regulates corpus cavernosum smooth muscle cell gap junctions and can ameliorate erectile dysfunction and how it modulates connexin43 (CX43) after bilateral cavernous neurectomy. Primary cultured rat corpus cavernosum smooth muscle cells were treated with PDGF-BB with or without a PDGFR inhibitor, Akt siRNA or the depletion or promotion of β-catenin. PDGF-BB improved CCSMCs gap junction coupling and increased CX43 and PDGFRβ expression; inhibition of PDGFR activity down-regulated CX43 and decreased Akt and nuclear β-catenin. Knockdown or promotion of β-catenin down-regulated and up-regulated CX43 expression respectively. Moreover, β-catenin activation induced CX43 nuclear accumulation, which impeded CX43 down-regulation induced by PDGFR inhibition, suggesting that CX43 expression is positively correlated with nuclear β-catenin expression. Furthermore, CX43 promoter luciferase and chromatin immunoprecipitation assays indicated that β-catenin regulates CX43 transcription by directly interacting with its promoter. Male rats underwent bilateral cavernous neurectomy. After 12 weeks, they were injected with PDGF-BB, CX43 and PDGFRβ expression was significantly lower than in the control group, which was reversed by PDGF-BB injection. These results suggested that PDGF-BB contributed to the improvement of gap junction intracellular communication among corpus cavernosum smooth muscle cells, increased CX43 through PDGFRβ/Akt/nuclear β-catenin signalling, and ameliorated cavernous nerve injury-induced erectile dysfunction.
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Affiliation(s)
- Fan Zhao
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Junfeng Yan
- Department of Urology, Zhejiang Hospital, Hangzhou, China
| | - Jianfeng Zhao
- Department of Urology and Andrology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Bing Shi
- Department of Urology, Nantong Hospital of Traditional Chinese Medicine, Nantong, China
| | - Miaoyong Ye
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaojun Huang
- Department of Urology and Andrology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Bo Yu
- Technology and Development Center for TCM of China, Beijing, China
| | - Bodong Lv
- Department of Urology and Andrology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China.,Andrology Laboratory on Integration of Chinese and Western Medicine, Zhejiang Provincial Key Laboratory of Traditional Chinese Medicine, Hangzhou, China
| | - Wenjie Huang
- Department of Urology and Andrology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
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López C, Aguilar R, Nardocci G, Cereceda K, Vander Stelt K, Slebe JC, Montecino M, Concha II. Wnt/β-catenin signaling enhances transcription of the CX43 gene in murine Sertoli cells. J Cell Biochem 2018; 120:6753-6762. [PMID: 30417410 DOI: 10.1002/jcb.27973] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 10/02/2018] [Indexed: 01/12/2023]
Abstract
Sertoli cells provide the nutritional and metabolic support for germ cells. Wnt/β-catenin signaling is important for the development of the seminiferous epithelium during embryonic age, although after birth this pathway is downregulated. Cx43 gene codes for a protein that is critical during testicular development. The Cx43 promoter contains TCF/β-catenin binding elements (TBEs) that contribute CX43 expression in different cell types and which may also be regulating the expression of this gene in Sertoli cells. In this study, we demonstrate that 42GPA9 Sertoli cells respond to treatments that result in accumulation of β-catenin within the nucleus and in upregulation of CX43 gene transcription. β-Catenin binds to TBEs located both upstream and downstream of the transcriptional start site (TSS). Luciferase reporter experiments revealed that TBEs located upstream of the TSS are necessary for β-catenin-mediated upregulation. Our results also indicate that the Wnt/β-catenin-dependent upregulation of the Cx43 gene in Sertoli cells is accompanied by changes in epigenetic parameters that may be directly contributing to generating a chromatin environment that facilitates the establishment of the transcriptional machinery at this promoter.
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Affiliation(s)
- Camila López
- Instituto de Bioquimíca y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Rodrigo Aguilar
- Center for Biomedical Research and FONDAP Center for Genome Regulation, Universidad Andrés Bello, Santiago, Chile
| | - Gino Nardocci
- Center for Biomedical Research and FONDAP Center for Genome Regulation, Universidad Andrés Bello, Santiago, Chile
| | - Karina Cereceda
- Instituto de Bioquimíca y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Karen Vander Stelt
- Instituto de Bioquimíca y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Juan Carlos Slebe
- Instituto de Bioquimíca y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Martin Montecino
- Center for Biomedical Research and FONDAP Center for Genome Regulation, Universidad Andrés Bello, Santiago, Chile
| | - Ilona I Concha
- Instituto de Bioquimíca y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
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Liu XY, Li X, Bai MR, Chen X, Wang CL, Xie J, Ye L. FGF-7 Dictates Osteocyte Cell Processes Through Beta-Catenin Transduction. Sci Rep 2018; 8:14792. [PMID: 30287900 PMCID: PMC6172271 DOI: 10.1038/s41598-018-33247-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/26/2018] [Indexed: 02/05/2023] Open
Abstract
It is well recognized that osteocytes communicate with each other via gap junctions and that connxin43 (Cx43) shows its great potential in gap junction for the contribution enabling transmission of small molecules and operating in an autocrine/a paracrine manner. Fibroblast growth factors (FGFs) play significant roles in new bone formation and adult bone remodeling, and FGF signaling is regulated by the precise spatiotemporal approaches. However, the influence of FGF7 on osteocyte cell processes is not well elucidated. In this study, we aimed to examine the impact of FGF7 on osteocyte cell processes by characterizing the expression of Cx43 and to reveal the underlying mechanism regulating this cell process. We first found that the mRNA level of FGF7 was higher relative to other FGF family members both in osteocytes cell line (MLO-Y4) and bone tissue. We then demonstrated that FGF7 could increase the expression of Cx43 in osteocytes and promote the cell processes in the form of gap junctions between osteocytes. This modulation was due to the FGF7-induced cytoplasmic accumulation and resultant nuclear translocation of β-catenin. Our results could help us to further understand the importance of FGF7 on bone cell behavior and bone physiology and even pathology.
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Affiliation(s)
- Xiao-Yu Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xin Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ming-Ru Bai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xia Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Cheng-Lin Wang
- 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.
| | - Ling Ye
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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38
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Regulation of connexin 43 expression in human gingival fibroblasts. Exp Cell Res 2018; 371:238-249. [PMID: 30118696 DOI: 10.1016/j.yexcr.2018.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/31/2018] [Accepted: 08/13/2018] [Indexed: 12/22/2022]
Abstract
AIMS Abundance of connexin 43 (Cx43), a transmembrane protein that forms hemichannels (HCs) and gap junctions (GJs), is dynamically regulated in human gingival fibroblasts (GFBLs) during wound healing. This may be important for fast and scarless gingival wound healing as Cx43 is involved in key cell functions important during this process. Our aim was to uncover the factors that regulate Cx43 expression and abundance in GFBLs. We hypothesized that cytokines and growth factors released during wound healing coordinately regulate Cx43 abundance in GFBLs. RESULTS TGF-β1, -β2, -β3, PGE2 and IL-1β significantly upregulated, while TNF-α and IFN-γ downregulated Cx43 in cultured GFBLs. TGF-β1, -β2, -β3, IL-1β and IFN-γ modulated Cx43 abundance at both mRNA and protein levels, while TNF-α and PGE2 regulated only Cx43 protein abundance, suggesting involvement of distinct transcriptional/post-transcriptional and translational/post-translational mechanisms, respectively. TGF-β1-induced upregulation of Cx43 was mediated by TGFβRI (ALK5) and SMAD2/3 signaling, and this was potently suppressed by PGE2, IL-1β, TNF-α and IFN-γ that inhibited SMAD2/3 phosphorylation. CONCLUSION Regulation of Cx43 abundance in GFBLs involves transcriptional/post-transcriptional and translational/post-translational mechanisms that are distinctly modulated by an interplay between TGF-β isoforms and PGE2, IL-1β, TNF-α and IFN-γ.
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Zhang B, He L, Liu Y, Zhang J, Zeng Q, Wang S, Fan Z, Fang F, Chen L, Lv Y, Xi J, Yue W, Li Y, Pei X. Prostaglandin E 2 Is Required for BMP4-Induced Mesoderm Differentiation of Human Embryonic Stem Cells. Stem Cell Reports 2018; 10:905-919. [PMID: 29478896 PMCID: PMC5919771 DOI: 10.1016/j.stemcr.2018.01.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 01/20/2018] [Accepted: 01/22/2018] [Indexed: 01/05/2023] Open
Abstract
The accurate control of early cell fate specification during differentiation of human embryonic stem cells (hESCs) is critical for acquiring pure therapeutic cell populations of interest. Bone morphogenetic protein 4 (BMP4) is a key mesoderm inducer from ESCs. However, the molecular mechanism of the mesodermal cell fate decision induced by BMP4 remains unclear. Here, we demonstrate the requirement of a bioactive lipid, prostaglandin E2 (PGE2), for the mesoderm specification from hESCs by BMP4 induction. We show that BMP4 directly regulates the expression of the key enzyme for PGE2 synthesis, COX-1, and promotes PGE2 production. More importantly, in the absence of BMP4, forced COX-1 expression or PGE2 treatment is sufficient to initiate mesoderm specification of hESCs by activation of EP2-PKA signaling and modulation of nuclear translocation of β-catenin. Together, our findings provide insights into the critical role of BMP regulation of PGE2 synthesis and its downstream signaling in initiating mesoderm commitment of hESCs. COX-1 and PGE2 played pivotal roles in the mesoderm specification of hESCs Specific inhibition of COX-1 suppressed mesoderm differentiation of hESCs BMP4 directly upregulated the transcription of the COX-1 PGE2 stimulated differentiation mainly via the EP2-PKA-GSK3β/β-catenin signaling pathway
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Affiliation(s)
- Bowen Zhang
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Lijuan He
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Yiming Liu
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Jing Zhang
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Quan Zeng
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Sihan Wang
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Zeng Fan
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Fang Fang
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Lin Chen
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Yang Lv
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Jiafei Xi
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Wen Yue
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China
| | - Yanhua Li
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China.
| | - Xuetao Pei
- Stem Cell and Regenerative Medicine Lab, Beijing Institute of Transfusion Medicine, Beijing 100850, China; South China Research Center for Stem Cell & Regenerative Medicine, SCIB, Guangzhou 510005, China.
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Srivastava T, Dai H, Heruth DP, Alon US, Garola RE, Zhou J, Duncan RS, El-Meanawy A, McCarthy ET, Sharma R, Johnson ML, Savin VJ, Sharma M. Mechanotransduction signaling in podocytes from fluid flow shear stress. Am J Physiol Renal Physiol 2018; 314:F22-F34. [PMID: 28877882 PMCID: PMC5866353 DOI: 10.1152/ajprenal.00325.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/21/2017] [Accepted: 08/28/2017] [Indexed: 12/28/2022] Open
Abstract
Recently, we and others have found that hyperfiltration-associated increase in biomechanical forces, namely, tensile stress and fluid flow shear stress (FFSS), can directly and distinctly alter podocyte structure and function. The ultrafiltrate flow over the major processes and cell body generates FFSS to podocytes. Our previous work suggests that the cyclooxygenase-2 (COX-2)-PGE2-PGE2 receptor 2 (EP2) axis plays an important role in mechanoperception of FFSS in podocytes. To address mechanotransduction of the perceived stimulus through EP2, cultured podocytes were exposed to FFSS (2 dyn/cm2) for 2 h. Total RNA from cells at the end of FFSS treatment, 2-h post-FFSS, and 24-h post-FFSS was used for whole exon array analysis. Differentially regulated genes ( P < 0.01) were analyzed using bioinformatics tools Enrichr and Ingenuity Pathway Analysis to predict pathways/molecules. Candidate pathways were validated using Western blot analysis and then further confirmed to be resulting from a direct effect of PGE2 on podocytes. Results show that FFSS-induced mechanotransduction as well as exogenous PGE2 activate the Akt-GSK3β-β-catenin (Ser552) and MAPK/ERK but not the cAMP-PKA signal transduction cascades. These pathways are reportedly associated with FFSS-induced and EP2-mediated signaling in other epithelial cells as well. The current regimen for treating hyperfiltration-mediated injury largely depends on targeting the renin-angiotensin-aldosterone system. The present study identifies specific transduction mechanisms and provides novel information on the direct effect of FFSS on podocytes. These results suggest that targeting EP2-mediated signaling pathways holds therapeutic significance for delaying progression of chronic kidney disease secondary to hyperfiltration.
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Affiliation(s)
- Tarak Srivastava
- Section of Nephrology, Children's Mercy Hospital and University of Missouri at Kansas City , Kansas City, Missouri
- Renal Research Laboratory, Research and Development, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri at Kansas City , Kansas City, Missouri
| | - Hongying Dai
- Section of Nephrology, Children's Mercy Hospital and University of Missouri at Kansas City , Kansas City, Missouri
| | - Daniel P Heruth
- Department of Experimental and Translational Genetics Research, Children's Mercy Hospital and University of Missouri at Kansas City , Kansas City, Missouri
| | - Uri S Alon
- Section of Nephrology, Children's Mercy Hospital and University of Missouri at Kansas City , Kansas City, Missouri
| | - Robert E Garola
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital and University of Missouri at Kansas City , Kansas City, Missouri
| | - Jianping Zhou
- Renal Research Laboratory, Research and Development, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
| | - R Scott Duncan
- Department of Ophthalmology, University of Missouri at Kansas City , Kansas City, Missouri
| | - Ashraf El-Meanawy
- Division of Nephrology, Medical College of Wisconsin , Milwaukee, Wisconsin
| | - Ellen T McCarthy
- Kidney Institute, University of Kansas Medical Center , Kansas City, Kansas
| | - Ram Sharma
- Renal Research Laboratory, Research and Development, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
| | - Mark L Johnson
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri at Kansas City , Kansas City, Missouri
| | - Virginia J Savin
- Renal Research Laboratory, Research and Development, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
- Kidney Institute, University of Kansas Medical Center , Kansas City, Kansas
| | - Mukut Sharma
- Renal Research Laboratory, Research and Development, Kansas City Veterans Affairs Medical Center , Kansas City, Missouri
- Kidney Institute, University of Kansas Medical Center , Kansas City, Kansas
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Zhou S, Fang Z, Wang G, Wu S. Gap junctional intercellular communication dysfunction mediates the cognitive impairment induced by cerebral ischemia-reperfusion injury: PI3K/Akt pathway involved. Am J Transl Res 2017; 9:5442-5451. [PMID: 29312496 PMCID: PMC5752894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE Cerebral ischemia/reperfusion (I/R) injury causes hippocampal apoptosis and cognitive impairment, and the dysfunction of gap junction intercellular communication (GJIC) may contribute to the cognitive impairment. We aim to examine the impact of cerebral I/R injury on cognitive impairment, the role of GJIC dysfunction in the rat hippocampus and the involvement of the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathway. METHODS Rats were subjected to a cerebral I/R procedure and underwent cognitive assessment with the novel object recognition and Morris Water Maze tasks. The distance of Lucifer Yellow dye transfer and the Cx43 protein were examined to measure GJIC. Neural apoptosis was assessed with the terminal deoxynucleotide-transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) method. After rats received inhibitors of the PI3K/Akt pathway, GJIC and cognitive ability were measured again. RESULTS GJIC promotion by ZP123 significantly reversed cognitive impairment and hippocampal apoptosis induced by cerebral I/R, while the inhibition of GJIC by octanol significantly facilitated cognitive impairment and hippocampal apoptosis. The phosphorylation of Akt was enhanced by cerebral I/R and octanol but inhibited by ZP123. The inhibition of the PI3K/Akt pathway significantly suppressed GJIC and cognitive impairment. CONCLUSION The PI3K/Akt pathway is involved in cognitive impairment caused by gap junctional communication dysfunction in the rat hippocampus after ischemia-reperfusion injury.
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Affiliation(s)
- Shujun Zhou
- Department of Critical Care Medicine, The Third Affiliated Hospital of Soochow University, The First People’s Hospital of ChangzhouChangzhou, Jiangsu, People’s Republic of China
| | - Zheng Fang
- Emergency Department, The Third Affiliated Hospital of Soochow University, The First People’s Hospital of ChangzhouChangzhou, Jiangsu, People’s Republic of China
| | - Gui Wang
- Department of Critical Care Medicine, The Third Affiliated Hospital of Soochow University, The First People’s Hospital of ChangzhouChangzhou, Jiangsu, People’s Republic of China
| | - Song Wu
- Emergency Department, The Third Affiliated Hospital of Soochow University, The First People’s Hospital of ChangzhouChangzhou, Jiangsu, People’s Republic of China
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42
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Zhang X, Zhao F, Zhao JF, Fu HY, Huang XJ, Lv BD. PDGF-mediated PI3K/AKT/β-catenin signaling regulates gap junctions in corpus cavernosum smooth muscle cells. Exp Cell Res 2017; 362:252-259. [PMID: 29174980 DOI: 10.1016/j.yexcr.2017.11.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/17/2017] [Accepted: 11/18/2017] [Indexed: 02/06/2023]
Abstract
Erectile dysfunction (ED) is the most common sexual disorder that men report to healthcare providers. Gap junctions (GJs) are thought to be responsible for synchronous shrinkage of corpus cavernosum smooth muscle cells (CCSMCs), and play thus an important role in the maintenance of an erection. Hypoxia has been suggested as a pathological mechanism underlying ED. Here we demonstrate that hypoxia increased the expression of platelet-derived growth factor (PDGF) and the main GJ component connexin (Cx)43 in CCSMCs. Inhibiting PDGF receptor (PDGFR) activity decreased Cx43 expression. Treatment with different concentrations of PDGF increased the levels of phosphorylated protein kinase B (AKT), β-catenin, and Cx43, whereas inhibition of PDGFR or activation of phosphatidylinositol 3 kinase (PI3K)/AKT signaling altered β-catenin and Cx43 expression. Meanwhile, silencing β-catenin resulted in the downregulation of Cx43. These results demonstrate that PDGF secretion by CCSMCs and vascular endothelial cells is enhanced under hypoxic conditions, leading to increased Cx43 expression through PI3K/AKT/β-catenin signaling and ultimately affecting GJ function in ED. Thus, targeting this pathway is a potential therapeutic strategy for the treatment of ED.
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Affiliation(s)
- Xiang Zhang
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Fan Zhao
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jian-Feng Zhao
- Department of Urology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Hui-Ying Fu
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China; Andrology Laboratory on Integration of Chinese and Western Medicine, Zhejiang Provincial Key Laboratory of Traditional Chinese Medicine, Hangzhou, China
| | - Xiao-Jun Huang
- Department of Urology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Bo-Dong Lv
- Department of Urology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China; Andrology Laboratory on Integration of Chinese and Western Medicine, Zhejiang Provincial Key Laboratory of Traditional Chinese Medicine, Hangzhou, China.
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43
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Subramaniam M, Cicek M, Pitel KS, Bruinsma ES, Nelson Holte MH, Withers SG, Rajamannan NM, Secreto FJ, Venuprasad K, Hawse JR. TIEG1 modulates β-catenin sub-cellular localization and enhances Wnt signaling in bone. Nucleic Acids Res 2017; 45:5170-5182. [PMID: 28201653 PMCID: PMC5435970 DOI: 10.1093/nar/gkx118] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 02/08/2017] [Indexed: 11/15/2022] Open
Abstract
We have previously demonstrated that TGFβ Inducible Early Gene-1 (TIEG1), also known as KLF10, plays important roles in mediating skeletal development and homeostasis in mice. TIEG1 has also been identified in clinical studies as one of a handful of genes whose altered expression levels or allelic variations are associated with decreased bone mass and osteoporosis in humans. Here, we provide evidence for the first time that TIEG1 is involved in regulating the canonical Wnt signaling pathway in bone through multiple mechanisms of action. Decreased Wnt signaling in the absence of TIEG1 expression is shown to be in part due to impaired β-catenin nuclear localization resulting from alterations in the activity of AKT and GSK-3β. We also provide evidence that TIEG1 interacts with, and serves as a transcriptional co-activator for, Lef1 and β-catenin. Changes in Wnt signaling in the setting of altered TIEG1 expression and/or activity may in part explain the observed osteopenic phenotype of TIEG1 KO mice as well as the known links between TIEG1 expression levels/allelic variations and patients with osteoporosis.
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Affiliation(s)
| | - Muzaffer Cicek
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Kevin S Pitel
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Elizabeth S Bruinsma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Molly H Nelson Holte
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Sarah G Withers
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Nalini M Rajamannan
- Division of Cardiology, Most Sacred Heart of Jesus Cardiology and Valvular Institute, Sheboygan, WI 53081, USA
| | - Frank J Secreto
- Division of General Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - K Venuprasad
- Baylor Institute for Immunology Research, Baylor Research Institute, Dallas, TX 75204, USA
| | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
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Hyperfiltration-associated biomechanical forces in glomerular injury and response: Potential role for eicosanoids. Prostaglandins Other Lipid Mediat 2017; 132:59-68. [PMID: 28108282 DOI: 10.1016/j.prostaglandins.2017.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 12/22/2016] [Accepted: 01/10/2017] [Indexed: 12/29/2022]
Abstract
Hyperfiltration is a well-known risk factor in progressive loss of renal function in chronic kidney disease (CKD) secondary to various diseases. A reduced number of functional nephrons due to congenital or acquired cause(s) results in hyperfiltration in the remnant kidney. Hyperfiltration-associated increase in biomechanical forces, namely pressure-induced tensile stress and fluid flow-induced shear stress (FFSS) determine cellular injury and response. We believe the current treatment of CKD yields limited success because it largely attenuates pressure-induced tensile stress changes but not the effect of FFSS on podocytes. Studies on glomerular podocytes, tubular epithelial cells and bone osteocytes provide evidence for a significant role of COX-2 generated PGE2 and its receptors in response to tensile stress and FFSS. Preliminary observations show increased urinary PGE2 in children born with a solitary kidney. FFSS-induced COX2-PGE2-EP2 signaling provides an opportunity to identify targets and, for developing novel agents to complement currently available treatment.
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45
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The molecular basis of bone mechanotransduction. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2016; 16:221-36. [PMID: 27609037 PMCID: PMC5114345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The skeleton has the ability to perfectly adapt to external forces of the operating environment, by altering its morphology and metabolism in order to meet different needs. This unique adaptive capacity of the skeleton creates an interesting range of biological questions concerning the perception of mechanical or other kinds of signals, the type of receptor, and the molecular pathways involved in this adaptation. Studies of the characteristics of the cellular engineering provide a host of new information that confers to osteocytes the role of the protagonist in the perception and regulation of mechanical effects on the skeleton. The identity of mechanoreceptors is manifold and concerns ion channels, integrins, cell membrane, the cytoskeleton, and other systems. A similar multiplicity characterizes the intracellular signaling. This review describes recent data concerning the outward force reception systems and intracellular transduction pathways of information transfer leading to the continuous adaptation of bone tissue. Increased appreciation of the importance of the mechanical environment in regulating and determining the effectiveness of structural adjustment of the skeleton defines new horizons for the discovery of novel therapeutic approaches to diseases associated with bone loss.
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Duan P, Bonewald LF. The role of the wnt/β-catenin signaling pathway in formation and maintenance of bone and teeth. Int J Biochem Cell Biol 2016; 77:23-29. [PMID: 27210503 DOI: 10.1016/j.biocel.2016.05.015] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 02/05/2023]
Abstract
The Wnt signaling pathway is known as one of the important molecular cascades that regulate cell fate throughout lifespan. The Wnt signaling pathway is further separated into the canonical signaling pathway that depends on the function of β-catenin (Wnt/β-catenin pathway) and the noncanonical pathways that operate independently of β-catenin (planar cell polarity pathway and Wnt/Ca(2+) pathway). The Wnt/β-catenin signaling pathway is complex and consists of numerous receptors, inhibitors, activators, modulators, phosphatases, kinases and other components. However, there is one central, critical molecule to this pathway, β-catenin. While there are at least 3 receptors, LRP 4, 5 and 6, and over twenty activators known as the wnts, and several inhibitors such as sclerostin, dickkopf and secreted frizzled-related protein, these all target β-catenin. These regulators/modulators function to target β-catenin either to the proteasome for degradation or to the nucleus to regulate gene expression. Therefore, the interaction of β-catenin with different factors and Wnt/β-catenin signaling pathway will be the subject of this review with a focus on how this pathway relates to and functions in the formation and maintenance of bone and teeth based on mainly basic and pre-clinical research. Also in this review, the role of this pathway in osteocytes, bone cells embedded in the mineralized matrix, is covered in depth. This pathway is not only important in mineralized tissue growth and development, but for modulation of the skeleton in response to loading and unloading and the viability and health of the adult and aging skeleton.
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Affiliation(s)
- Peipei Duan
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - L F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA.
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Gupta A, Anderson H, Buo AM, Moorer MC, Ren M, Stains JP. Communication of cAMP by connexin43 gap junctions regulates osteoblast signaling and gene expression. Cell Signal 2016; 28:1048-57. [PMID: 27156839 DOI: 10.1016/j.cellsig.2016.04.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 04/15/2016] [Accepted: 04/28/2016] [Indexed: 11/30/2022]
Abstract
Connexin43 (Cx43) containing gap junctions play an important role in bone homeostasis, yet little is known about the second messengers communicated by Cx43 among bone cells. Here, we used MC3T3-E1 pre-osteoblasts and UMR106 rat osteosarcoma cells to test the hypothesis that cAMP is a second messenger communicated by bone cells through Cx43 containing gap junctions in a manner that is sufficient to impact osteoblast function. Overexpression of Cx43 markedly enhanced the activity of a cAMP-response element driven transcriptional luciferase reporter (CRE-luc) and increased phospho-CREB and phospho-ERK1/2 levels following expression of a constitutively active Gsα or by treatment with prostaglandin E2 (PGE2), 3-Isobutyl-1-methyl xanthine (IBMX) or forskolin. The Cx43-dependent potentiation of signaling in PGE2 treated cells was not accompanied by a further increase in cAMP levels, suggesting that the cAMP was shared between cells rather than Cx43 enhancing cAMP production. To support this, we developed a novel assay in which one set of cells expressing constitutively active Gsα (donor cells) were co-cultured with a second set of cells expressing a CRE-luc reporter (acceptor cells). Using this assay, activation of a CRE-luc reporter in the acceptor cells was both Cx43- and cell contact-dependent, indicating communication of cAMP among cells. Finally, we showed that Cx43 increased the cAMP-dependent mRNA expression of receptor activator of nuclear factor kappa B ligand (RANKL) and enhanced the repression of the sclerostin mRNA, implying a potential mechanism for the modulation of tissue remodeling. In total, these data demonstrate that Cx43 can communicate cAMP between cells and, more importantly, that the communicated cAMP is sufficient to impact signal transduction cascades and the expression of key bone effector molecules between interconnected cells.
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Affiliation(s)
- Aditi Gupta
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hidayah Anderson
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Atum M Buo
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Megan C Moorer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Margaret Ren
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA.
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48
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Riquelme MA, Burra S, Kar R, Lampe PD, Jiang JX. Mitogen-activated Protein Kinase (MAPK) Activated by Prostaglandin E2 Phosphorylates Connexin 43 and Closes Osteocytic Hemichannels in Response to Continuous Flow Shear Stress. J Biol Chem 2015; 290:28321-28328. [PMID: 26442583 DOI: 10.1074/jbc.m115.683417] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 01/04/2023] Open
Abstract
Cx43 hemichannels serve as a portal for the release of prostaglandins, a critical process in mediating biological responses of mechanical loading on bone formation and remodeling. We have previously observed that fluid flow shear stress (FFSS) opens hemichannels; however, sustained FFSS results in hemichannel closure, as continuous opening of hemichannels is detrimental to cell viability and bone remodeling. However, the mechanism that regulates the closure of the hemichannels is unknown. Here, we show that activation of p44/42 ERK upon continuous FFSS leads to Cx43 phosphorylation at Ser(279)-Ser(282), sites known to be phosphorylated sites by p44/42 MAPK. Incubation of osteocytic MLO-Y4 cells with conditioned media (CM) collected after continuous FFSS increased MAPK-dependent phosphorylation of Cx43. CM treatment inhibited hemichannel opening and this inhibition was reversed when cells were pretreated with the MAPK pathway inhibitor. We found that prostaglandin E2 (PGE2) accumulates in the CM in a time-dependent manner. Treatment with PGE2 increased phospho-p44/42 ERK levels and also Cx43 phosphorylation at Ser(279)-Ser(282) sites. Depletion of PGE2 from CM, and pre-treatment with a p44/42 ERK pathway-specific inhibitor, resulted in a complete inhibition of ERK-dependent Cx43 phosphorylation and attenuated the inhibition of hemichannels by CM and PGE2. Consistently, the opening of hemichannels by FFSS was blocked by PGE2 and CM and this blockage was reversed by U0126 and the CM depleted of PGE2. A similar observation was also obtained in isolated primary osteocytes. Together, results from this study suggest that extracellular PGE2 accumulated after continuous FFSS is responsible for activation of p44/42 ERK signaling and subsequently, direct Cx43 phosphorylation by activated ERK leads to hemichannel closure.
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Affiliation(s)
- Manuel A Riquelme
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Sirisha Burra
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Rekha Kar
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - Paul D Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Jean X Jiang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900.
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Yang J, Qin G, Luo M, Chen J, Zhang Q, Li L, Pan L, Qin S. Reciprocal positive regulation between Cx26 and PI3K/Akt pathway confers acquired gefitinib resistance in NSCLC cells via GJIC-independent induction of EMT. Cell Death Dis 2015. [PMID: 26203858 PMCID: PMC4650742 DOI: 10.1038/cddis.2015.197] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Gefitinib efficiency in non-small-cell lung cancer (NSCLC) therapy is limited due to development of drug resistance. The molecular mechanisms of gefitinib resistance remain still unclear. In this study, we first found that connexin 26 (Cx26) is the predominant Cx isoform expressed in various NSCLC cell lines. Then, two gefitinib-resistant (GR) NSCLC cell lines, HCC827 GR and PC9 GR, from their parental cells were established. In these GR cells, the results showed that gefitinib resistance correlated with changes in cellular EMT phenotypes and upregulation of Cx26. Cx26 was detected to be accumulated in the cytoplasm and failed to establish functional gap-junctional intercellular communication (GJIC) either in GR cells or their parental cells. Ectopic expression of GJIC-deficient chimeric Cx26 was sufficient to induce EMT and gefitinib insensitivity in HCC827 and PC9 cells, while knockdown of Cx26 reversed EMT and gefitinib resistance in their GR cells both in vitro and in vivo. Furthermore, Cx26 overexpression could activate PI3K/Akt signaling in these cells. Cx26-mediated EMT and gefitinib resistance were significantly blocked by inhibition of PI3K/Akt pathway. Specifically, inhibition of the constitutive activation of PI3K/Akt pathway substantially suppressed Cx26 expression, and Cx26 was confirmed to functionally interplay with PI3K/Akt signaling to promote EMT and gefitinib resistance in NSCLC cells. In conclusion, the reciprocal positive regulation between Cx26 and PI3K/Akt signaling contributes to acquired gefitinib resistance in NSCLC cells by promoting EMT via a GJIC-independent manner.
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Affiliation(s)
- J Yang
- Department of Pharmacology, School of Pharmacy, Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, Guangxi, China
| | - G Qin
- Department of Pharmacology, School of Pharmacy, Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, Guangxi, China
| | - M Luo
- Department of Pharmacology, School of Pharmacy, Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, Guangxi, China
| | - J Chen
- Department of Hepatobiliary Surgery, Affiliated Cancer Hospital, Guangxi Medical University, 71 Hedi Road, Nanning 530021, Guangxi, China
| | - Q Zhang
- Department of Pharmacology, School of Pharmacy, Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, Guangxi, China
| | - L Li
- Division of Pulmonary, Department of Medicine, Allergy and Critical Care, Lung Biology Laboratory, Columbia University Medical Center, New York, NY 10032, USA
| | - L Pan
- Nephrology Division, The First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning 530021, Guangxi, China
| | - S Qin
- Department of Respiratory Medicine, The First Affiliated Hospital, Guangxi Medical University, 6 Shuangyong Road, Nanning 530021, Guangxi, China
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50
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Up-Regulation of the Biosynthesis and Release of Substance P through Wnt/β-Catenin Signaling Pathway in Rat Dorsal Root Ganglion Cells. PLoS One 2015; 10:e0129701. [PMID: 26054011 PMCID: PMC4459973 DOI: 10.1371/journal.pone.0129701] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 05/12/2015] [Indexed: 11/19/2022] Open
Abstract
To examine regulatory effects of β-catenin on the biosynthesis and release of substance P, a rat chronic constriction injury (CCI) model and a rat dorsal root ganglion (DRG) cell culture model were used in the present study. The CCI treatment significantly induced the overall expression of β-catenin (158 ± 6% of sham) in the ipsilateral L5 DRGs in comparison with the sham group (109 ± 4% of sham). The CCI-induced aberrant expression of β-catenin was significantly attenuated by oral administration of diclofenac (119 ± 6% of the sham value; 10 mg/kg). Importantly, aberrant nuclear accumulation of β-catenin in cultured DRG cells resulted in up-regulation of the PPT-A mRNA expression and the substance P release. The up-regulation of both the PPT-A mRNA expression and the substance P release by either a GSK-3β inhibitor TWS119 (10 μM) or a Wnt signaling agonist Wnt-3a (100 ng/ml) were significantly abolished by an inhibitor of cyclooxygenase-2 (COX-2; NS-398, 1 μM). Collectively, these data suggest that nociceptive input-activated β-catenin signaling plays an important role in regulating the biosynthesis and release of substance P, which may contribute to the inflammation responses related to chronic pain.
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