TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice

We investigated the ability of neutrophils to express receptor activator of nuclear factor kappa-B ligand (RANKL), to secrete osteoprotegerin (OPG), and to produce IL-17. Arthritis was induced by intra-articular injection of zymosan, a ligand for Toll-like receptor 2 (TLR2). Frequencies of neutrophi...

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Main Authors: Viktoriya Milanova, Nina Ivanovska, Petya Dimitrova
Format: Article
Language:English
Published: Wiley 2014-01-01
Series:Mediators of Inflammation
Online Access:http://dx.doi.org/10.1155/2014/643406
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author Viktoriya Milanova
Nina Ivanovska
Petya Dimitrova
author_facet Viktoriya Milanova
Nina Ivanovska
Petya Dimitrova
author_sort Viktoriya Milanova
collection DOAJ
description We investigated the ability of neutrophils to express receptor activator of nuclear factor kappa-B ligand (RANKL), to secrete osteoprotegerin (OPG), and to produce IL-17. Arthritis was induced by intra-articular injection of zymosan, a ligand for Toll-like receptor 2 (TLR2). Frequencies of neutrophils in bone marrow (BM), blood and synovial fluid (SF), receptor expression, and cytokine production were evaluated by flow cytometry. 1A8 antibody (1A8 Ab) was used to deplete neutrophils in zymosan-injected SCID mice. IL-17, RANKL, and OPG amounts in SF, serum, or cell cultures were determined by ELISA. The development of arthritis was associated with increased secretion of IL-17, RANKL, and OPG in serum and SF, elevated frequencies of Ly6G+CD11b+ cells in BM, blood, and SF and upregulated RANKL expression. Both IL-17 and OPG were absent in serum and SF after neutrophil depletion; therefore we assume that they were released by neutrophils. In vitro blood Ly6G+CD11b+ cells from arthritic mice produced spontaneously IL-17, IFN-γ, and OPG and expressed RANKL. This phenotype was sustained by IL-17. TLR2 engagement increased IL-17 and IFN-γ production, potentiated IL-17-mediated RANKL expression, and inhibited OPG secretion. We conclude that TLR2 regulates the destructive potential of neutrophils and its targeting might limit joint alterations in arthritis.
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spelling doaj-art-2f762fdba7ce4b68bae67d47f0b9d4de2025-02-03T01:11:59ZengWileyMediators of Inflammation0962-93511466-18612014-01-01201410.1155/2014/643406643406TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic MiceViktoriya Milanova0Nina Ivanovska1Petya Dimitrova2Department of Immunology, Institute of Microbiology, Bulgarian Academy of Sciences, 26 Georgi Bonchev street, 1113 Sofia, BulgariaDepartment of Immunology, Institute of Microbiology, Bulgarian Academy of Sciences, 26 Georgi Bonchev street, 1113 Sofia, BulgariaDepartment of Immunology, Institute of Microbiology, Bulgarian Academy of Sciences, 26 Georgi Bonchev street, 1113 Sofia, BulgariaWe investigated the ability of neutrophils to express receptor activator of nuclear factor kappa-B ligand (RANKL), to secrete osteoprotegerin (OPG), and to produce IL-17. Arthritis was induced by intra-articular injection of zymosan, a ligand for Toll-like receptor 2 (TLR2). Frequencies of neutrophils in bone marrow (BM), blood and synovial fluid (SF), receptor expression, and cytokine production were evaluated by flow cytometry. 1A8 antibody (1A8 Ab) was used to deplete neutrophils in zymosan-injected SCID mice. IL-17, RANKL, and OPG amounts in SF, serum, or cell cultures were determined by ELISA. The development of arthritis was associated with increased secretion of IL-17, RANKL, and OPG in serum and SF, elevated frequencies of Ly6G+CD11b+ cells in BM, blood, and SF and upregulated RANKL expression. Both IL-17 and OPG were absent in serum and SF after neutrophil depletion; therefore we assume that they were released by neutrophils. In vitro blood Ly6G+CD11b+ cells from arthritic mice produced spontaneously IL-17, IFN-γ, and OPG and expressed RANKL. This phenotype was sustained by IL-17. TLR2 engagement increased IL-17 and IFN-γ production, potentiated IL-17-mediated RANKL expression, and inhibited OPG secretion. We conclude that TLR2 regulates the destructive potential of neutrophils and its targeting might limit joint alterations in arthritis.http://dx.doi.org/10.1155/2014/643406
spellingShingle Viktoriya Milanova
Nina Ivanovska
Petya Dimitrova
TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice
Mediators of Inflammation
title TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice
title_full TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice
title_fullStr TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice
title_full_unstemmed TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice
title_short TLR2 Elicits IL-17-Mediated RANKL Expression, IL-17, and OPG Production in Neutrophils from Arthritic Mice
title_sort tlr2 elicits il 17 mediated rankl expression il 17 and opg production in neutrophils from arthritic mice
url http://dx.doi.org/10.1155/2014/643406
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