The autoantigen DNA topoisomerase I interacts with chemokine receptor 7 and exerts cytokine-like effects on dermal fibroblasts.
Arthritis Rheum
; 64(3): 826-34, 2012 Mar.
Article
em En
| MEDLINE
| ID: mdl-21953548
ABSTRACT
OBJECTIVE:
Previous studies have demonstrated that, once released into the extracellular environment, the systemic sclerosis (SSc)-associated autoantigen DNA topoisomerase I (topo I) binds specifically to the surface of fibroblasts via an unknown receptor. We extended these results by identifying topo I-mediated cellular effects and characterizing the specific target of topo I on fibroblast surfaces.METHODS:
Purified topo I was used to investigate intracellular signaling pathway activation and tested for cell migration. To demonstrate the expression of specific chemokine receptors on fibroblasts, we performed immunoblotting and flow cytometry. To evaluate the direct interaction between chemokine receptor and topo I, a protein-protein based enzyme-linked immunosorbent assay (ELISA) was used. Finally, topo I coupled to the fluorochrome phycoerythrin (PE) was used to investigate competition of topo I specific binding on fibroblast surfaces with chemokine ligand.RESULTS:
Topo I stimulated the phosphorylation of phospholipase Cγ1, c-Raf, ERK-1/2, and p38 MAPK, intracellular signaling pathways that stimulated fibroblast migration via a G(αi) protein-coupled receptor. CCR7 was found to interact directly with topo I. Furthermore, its ligand, CCL21, competed in vitro for this interaction and in vivo with the binding of PE-coupled topo I to fibroblast surfaces.CONCLUSION:
These new roles of topo I in fibroblast physiology and the identification of its target on the cell surface demonstrate that topo I is a bifunctional autoantigen and open up new perspectives of study in the field of SSc-associated anti-topo I autoantibodies.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escleroderma Sistêmico
/
DNA Topoisomerases Tipo I
/
Receptores CCR7
/
Fibroblastos
Limite:
Humans
Idioma:
En
Revista:
Arthritis Rheum
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Canadá