Articular chondrocyte network mediated by gap junctions: role in metabolic cartilage homeostasis
| Autor: | P. Filgueira-Fernández, Gary S. Goldberg, Paula Carpintero-Fernández, Raquel Gago-Fuentes, Maria D. Mayan, Virginijus Valiunas, Peter R. Brink, Patricia Fernández-Puente, N. Goyanes, Francisco J. Blanco |
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| Rok vydání: | 2013 |
| Předmět: |
Cartilage
Articular Cell signaling Knee Joint Swine Immunology Cell Communication Matrix (biology) Biology Article Connexins General Biochemistry Genetics and Molecular Biology Chondrocytes Rheumatology medicine Animals Homeostasis Humans Immunoprecipitation Immunology and Allergy Cytoskeleton Cartilage homeostasis Electroporation Cartilage Gap junction Gap Junctions Vinculin Immunohistochemistry Cell biology Glucose medicine.anatomical_structure Biochemistry Microscopy Electron Scanning biology.protein Amino Acids Essential |
| Zdroj: | Annals of the Rheumatic Diseases. 74:275-284 |
| ISSN: | 1468-2060 0003-4967 |
| DOI: | 10.1136/annrheumdis-2013-204244 |
| Popis: | ObjectiveThis study investigated whether chondrocytes within the cartilage matrix have the capacity to communicate through intercellular connections mediated by voltage-gated gap junction (GJ) channels.MethodsFrozen cartilage samples were used for immunofluorescence and immunohistochemistry assays. Samples were embedded in cacodylate buffer before dehydration for scanning electron microscopy. Co-immunoprecipitation experiments and mass spectrometry (MS) were performed to identify proteins that interact with the C-terminal end of Cx43. GJ communication was studied through in situ electroporation, electrophysiology and dye injection experiments. A transwell layered culture system and MS were used to identify and quantify transferred amino acids.ResultsMicroscopic images revealed the presence of multiple cellular projections connecting chondrocytes within the matrix. These projections were between 5 and 150 µm in length. MS data analysis indicated that the C-terminus of Cx43 interacts with several cytoskeletal proteins implicated in Cx trafficking and GJ assembly, including α-tubulin and β-tubulin, actin, and vinculin. Electrophysiology experiments demonstrated that 12-mer oligonucleotides could be transferred between chondrocytes within 12 min after injection. Glucose was homogeneously distributed within 22 and 35 min. No transfer was detected when glucose was electroporated into A549 cells, which have no GJs. Transwell layered culture systems coupled with MS analysis revealed connexins can mediate the transfer of L-lysine and L-arginine between chondrocytes.ConclusionsThis study reveals that intercellular connections between chondrocytes contain GJs that play a key role in cell–cell communication and a metabolic function by exchange of nutrients including glucose and essential amino acids. A three-dimensional cellular network mediated through GJs might mediate metabolic and physiological homeostasis to maintain cartilage tissue. |
| Databáze: | OpenAIRE |
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