Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo
The extracellular form of the abundant heat shock protein, gp96, is involved in human autoimmune pathologies. In patients with type 1 diabetes, circulating gp96 is found to be elevated, and is bound to the acute-phase protein, α1-antitrypsin (AAT). The two molecules also engage intracellularly durin...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2013-10-01
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| Series: | Frontiers in Immunology |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fimmu.2013.00320/full |
| _version_ | 1828331932974317568 |
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| author | Eli Chaim Lewis David Elihai Ochayon Mark Ilan Mizrahi Galit eShahaf Boris Michael Baranovski |
| author_facet | Eli Chaim Lewis David Elihai Ochayon Mark Ilan Mizrahi Galit eShahaf Boris Michael Baranovski |
| author_sort | Eli Chaim Lewis |
| collection | DOAJ |
| description | The extracellular form of the abundant heat shock protein, gp96, is involved in human autoimmune pathologies. In patients with type 1 diabetes, circulating gp96 is found to be elevated, and is bound to the acute-phase protein, α1-antitrypsin (AAT). The two molecules also engage intracellularly during the physiological folding of AAT. AAT therapy promotes pancreatic islet survival in both transplantation and autoimmune diabetes models, and several clinical trials are currently examining AAT therapy for individuals with type 1 diabetes. However, its mechanism of action is yet unknown. Here, we examine whether the protective activity of AAT is related to binding of extracellular gp96. Primary mouse islets, macrophages and dendritic cells were added recombinant gp96 in the presence of clinical-grade human AAT (hAAT, GlassiaTM, Kamada Ltd, Israel). Islet function was evaluated by insulin release. The effect of hAAT on IL-1β/IFNγ-induced gp96 cell surface levels was also evaluated. In vivo, skin transplants were performed for examination of robust immune responses, and systemic inflammation was induced by cecal puncture. Endogenous gp96 was inhibited by gp96-inhibitory peptide (gp96i, Compugen Ltd., Israel) in an allogeneic islet transplantation model. Our findings indicate that hAAT binds to gp96 and diminishes gp96-induced inflammatory responses; e.g., hAAT-treated gp96-stimulated islets released less pro-inflammatory cytokines (IL-1β by 6.16-fold and TNFα by 2.69-fold) and regained gp96-disrupted insulin release. hAAT reduced cell activation during both skin transplantation and systemic inflammation, as well as lowered inducible surface levels of gp96 on immune cells. Finally, inhibition of gp96 significantly improved immediate islet graft function. These results suggest that hAAT is a regulator of gp96-mediated inflammatory responses, an increasingly appreciated endogenous damage response with relevance to human pathologies that are exacerbated by tissue injury. |
| first_indexed | 2024-04-13T20:59:56Z |
| format | Article |
| id | doaj.art-6da6db5109c341ec8b4620baf51264da |
| institution | Directory Open Access Journal |
| issn | 1664-3224 |
| language | English |
| last_indexed | 2024-04-13T20:59:56Z |
| publishDate | 2013-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Immunology |
| spelling | doaj.art-6da6db5109c341ec8b4620baf51264da2022-12-22T02:30:11ZengFrontiers Media S.A.Frontiers in Immunology1664-32242013-10-01410.3389/fimmu.2013.0032061674Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivoEli Chaim Lewis0David Elihai Ochayon1Mark Ilan Mizrahi2Galit eShahaf3Boris Michael Baranovski4Ben-Gurion University of the NegevBen-Gurion University of the NegevBen-Gurion University of the NegevBen-Gurion University of the NegevBen-Gurion University of the NegevThe extracellular form of the abundant heat shock protein, gp96, is involved in human autoimmune pathologies. In patients with type 1 diabetes, circulating gp96 is found to be elevated, and is bound to the acute-phase protein, α1-antitrypsin (AAT). The two molecules also engage intracellularly during the physiological folding of AAT. AAT therapy promotes pancreatic islet survival in both transplantation and autoimmune diabetes models, and several clinical trials are currently examining AAT therapy for individuals with type 1 diabetes. However, its mechanism of action is yet unknown. Here, we examine whether the protective activity of AAT is related to binding of extracellular gp96. Primary mouse islets, macrophages and dendritic cells were added recombinant gp96 in the presence of clinical-grade human AAT (hAAT, GlassiaTM, Kamada Ltd, Israel). Islet function was evaluated by insulin release. The effect of hAAT on IL-1β/IFNγ-induced gp96 cell surface levels was also evaluated. In vivo, skin transplants were performed for examination of robust immune responses, and systemic inflammation was induced by cecal puncture. Endogenous gp96 was inhibited by gp96-inhibitory peptide (gp96i, Compugen Ltd., Israel) in an allogeneic islet transplantation model. Our findings indicate that hAAT binds to gp96 and diminishes gp96-induced inflammatory responses; e.g., hAAT-treated gp96-stimulated islets released less pro-inflammatory cytokines (IL-1β by 6.16-fold and TNFα by 2.69-fold) and regained gp96-disrupted insulin release. hAAT reduced cell activation during both skin transplantation and systemic inflammation, as well as lowered inducible surface levels of gp96 on immune cells. Finally, inhibition of gp96 significantly improved immediate islet graft function. These results suggest that hAAT is a regulator of gp96-mediated inflammatory responses, an increasingly appreciated endogenous damage response with relevance to human pathologies that are exacerbated by tissue injury.http://journal.frontiersin.org/Journal/10.3389/fimmu.2013.00320/fullInflammationHeat shock proteindiabetespancreatic isletsα1-antitrypsinAllogeneic transplantation |
| spellingShingle | Eli Chaim Lewis David Elihai Ochayon Mark Ilan Mizrahi Galit eShahaf Boris Michael Baranovski Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo Frontiers in Immunology Inflammation Heat shock protein diabetes pancreatic islets α1-antitrypsin Allogeneic transplantation |
| title | Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo |
| title_full | Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo |
| title_fullStr | Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo |
| title_full_unstemmed | Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo |
| title_short | Human α1-antitrypin binds to heat-shock protein gp96 and protects from endogenous gp96-mediated injury in vivo |
| title_sort | human α1 antitrypin binds to heat shock protein gp96 and protects from endogenous gp96 mediated injury in vivo |
| topic | Inflammation Heat shock protein diabetes pancreatic islets α1-antitrypsin Allogeneic transplantation |
| url | http://journal.frontiersin.org/Journal/10.3389/fimmu.2013.00320/full |
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