RESUMO
The chemokine Cxcl1 plays a crucial role in recruiting neutrophils in response to infection. The early events in chemokine-mediated neutrophil extravasation involve a sequence of highly orchestrated steps including rolling, adhesion, arrest, and diapedesis. Cxcl1 function is determined by its properties of reversible monomer-dimer equilibrium and binding to Cxcr2 and glycosaminoglycans. Here, we characterized how these properties orchestrate extravasation using intravital microscopy of the cremaster. Compared to WT Cxcl1, which exists as both a monomer and a dimer, the trapped dimer caused faster rolling, less adhesion, and less extravasation. Whole-mount immunofluorescence of the cremaster and arrest assays confirmed these data. Moreover, the Cxcl1 dimer showed impaired LFA-1-mediated neutrophil arrest that could be attributed to impaired Cxcr2-mediated ERK signaling. We conclude that Cxcl1 monomer-dimer equilibrium and potent Cxcr2 activity of the monomer together coordinate the early events in neutrophil recruitment.
Assuntos
Glicosaminoglicanos , Neutrófilos , Quimiocina CXCL1/metabolismo , Neutrófilos/metabolismo , Movimento Celular , Glicosaminoglicanos/metabolismo , Quimiocinas/metabolismo , Infiltração de Neutrófilos , Receptores de Interleucina-8B/metabolismoRESUMO
PURPOSE: The aim was to investigate the systemic levels of cytokines and the expression of the chemokine receptor CXCR2 in circulating neutrophils in patients with non-neoplastic ovarian lesions, benign neoplasia or malignant neoplasia. MATERIALS AND METHODS: Controls and patients with ovarian tumours were pre-operatively compared for the production of cytokines (IL-2, IL-5, IL-6, IL-8, IL-10 and TNF-α) by ELISA, and for the expression of the chemokine receptor, CXCR2, in neutrophils, by flow cytometry. Randomly selected patients within the malignant group were re-evaluated for the inflammatory parameters at 30 days after surgery. RESULTS: The serum concentrations of IL-6, IL-8 and IL-10 were significantly higher in the benign and malignant neoplasia than in the control group, and their levels were significantly higher in ovarian cancer patients than in patients with non-neoplastic tumours or benign neoplasia. Treatment reduced IL-8 serum levels but did not affect CXCR2 expression in neutrophils. Cut-off values for IL-6, IL-8, and IL-10 comparing malignant vs. benign neoplasia were 11.3, 71.7, 14.8, and comparing malignant neoplasm vs. non-neoplastic lesions were 7.2, 43.5, 12.3, respectively. CONCLUSIONS: Serum IL-6, IL-8, and IL-10 levels, and expression of CXCR2 in circulating neutrophils seem promising for distinguishing ovarian cancer patients from patients with benign tumours.
Assuntos
Biomarcadores Tumorais/sangue , Citocinas/sangue , Neoplasias Ovarianas/sangue , Receptores de Interleucina-8B/sangue , Adulto , Idoso , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Interleucina-10/sangue , Interleucina-2/sangue , Interleucina-5/sangue , Interleucina-6/sangue , Interleucina-8/sangue , Pessoa de Meia-Idade , Neoplasias/sangue , Neoplasias/patologia , Neoplasias Ovarianas/patologia , Fator de Necrose Tumoral alfa/sangueRESUMO
The classic model of fever induction is based on the administration of lipopolysaccharide (LPS) from Gram-negative bacteria in experimental animals. LPS-induced fever results in the synthesis/release of many mediators that assemble an LPS-fever cascade. We have previously demonstrated that cytokine-induced neutrophil chemoattractant (CINC)-1, a Glu-Leu-Arg (ELR) + chemokine, centrally administered to rats, induces fever and increases prostaglandin E2 in the cerebrospinal fluid. We now attempt to investigate the involvement of CINC-1 and its functional receptor CXCR2 on the fever induced by exogenous and endogenous pyrogens in rats. We also investigated the effect of reparixin, an allosteric inhibitor of CXCR1/CXCR2 receptors, on fever induced by either systemic administration of LPS or intracerebroventricular injection of CINC-1, as well as TNF-α, IL-1ß, IL-6, or ET-1, known mediators of febrile response. Our results show increased CINC-1 mRNA expression in the liver, hypothalamus, CSF, and plasma following LPS injection. Moreover, reparixin administered right before CINC-1 or LPS abolished the fever induced by CINC-1 and significantly reduced the response induced by LPS. In spite of these results, reparixin does not modify the fever induced by IL-1ß, TNF-α, and IL-6, but significantly reduces ET-1-induced fever. Therefore, it is plausible to suggest that CINC-1 might contribute to LPS-induced fever in rats by activating CXCR2 receptor on the CNS. Moreover, it can be hypothesized that CINC-1 is placed upstream TNF-α, IL-1ß, and IL-6 among the prostaglandin-dependent fever-mediator cascade and amidst the prostaglandin-independent synthesis pathway of fever.