title: Citrullination of CXCL8 by peptidylarginine deiminase alters receptor usage, prevents proteolysis, and dampens tissue inflammation.
abstract: Biological functions of proteins are influenced by posttranslational modifications such as on/off switching by phosphorylation and modulation by glycosylation. Proteolytic processing regulates cytokine and chemokine activities. In this study, we report that natural posttranslational citrullination or deimination alters the biological activities of the neutrophil chemoattractant and angiogenic cytokine CXCL8/interleukin-8 (IL-8). Citrullination of arginine in position 5 was discovered on 14% of natural leukocyte-derived CXCL8(1-77), generating CXCL8(1-77)Cit(5). Peptidylarginine deiminase (PAD) is known to citrullinate structural proteins, and it may initiate autoimmune diseases. PAD efficiently and site-specifically citrullinated CXCL5, CXCL8, CCL17, CCL26, but not IL-1beta. In comparison with CXCL8(1-77), CXCL8(1-77)Cit(5) had reduced affinity for glycosaminoglycans and induced less CXCR2-dependent calcium signaling and extracellular signal-regulated kinase 1/2 phosphorylation. In contrast to CXCL8(1-77), CXCL8(1-77)Cit(5) was resistant to thrombin- or plasmin-dependent potentiation into CXCL8(6-77). Upon intraperitoneal injection, CXCL8(6-77) was a more potent inducer of neutrophil extravasation compared with CXCL8(1-77). Despite its retained chemotactic activity in vitro, CXCL8(1-77)Cit(5) was unable to attract neutrophils to the peritoneum. Finally, in the rabbit cornea angiogenesis assay, the equally potent CXCL8(1-77) and CXCL8(1-77)Cit(5) were less efficient angiogenic molecules than CXCL8(6-77). This study shows that PAD citrullinates the chemokine CXCL8, and thus may dampen neutrophil extravasation during acute or chronic inflammation.
authors: Laboratory of Molecular Immunology, Rega Institute, K.U.Leuven, Leuven, Belgium. paul.proost@rega.kuleuven.be
authors: Paul
authors: P
authors: Proost
authors: Tamara
authors: T
authors: Loos
authors: Anneleen
authors: A
authors: Mortier
authors: Evemie
authors: E
authors: Schutyser
authors: Mieke
authors: M
authors: Gouwy
authors: Samuel
authors: S
authors: Noppen
authors: Chris
authors: C
authors: Dillen
authors: Isabelle
authors: I
authors: Ronsse
authors: René
authors: R
authors: Conings
authors: Sofie
authors: S
authors: Struyf
authors: Ghislain
authors: G
authors: Opdenakker
authors: Prabhat C
authors: PC
authors: Maudgal
authors: Jo
authors: J
authors: Van Damme
mesh_terms: D000818:Animals; D001120:Arginine; D001327:Autoimmune Diseases; D002956:Citrulline / Q000737:chemistry*; D003315:Cornea / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D006867:Hydrolases / Q000378:metabolism*; D007249:Inflammation; D016209:Interleukin-8 / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D000076342:Protein-Arginine Deiminases; D011817:Rabbits
chemical_list: C508606:CXCL8 protein, human; D016209:Interleukin-8; D002956:Citrulline; D001120:Arginine; D006867:Hydrolases; D000076342:Protein-Arginine Deiminases