Induction of IL-13 production and upregulated expression of protease activated receptor-1 by RANTES in a mast cell line.
ABSTRACT RANTES is a potent chemoattractant for various important inflammatory cells such as eosinophils, memory T cells and mast cells. It has been long recognized as a crucial player in the pathogenesis of allergy. However, little is known of its effects on cytokine secretion and protease activated receptor (PAR) expression in mast cells. In the present study, we examined potential influence of RANTES on IL-13 and IL-12 release from P815 cells and PAR expression on P815 cells by using flow cytometry analysis, quantitative real-time PCR, ELISA and cellular activation of signaling ELISA (CASE) techniques. The results showed that RANTES induced up to 2.2-fold increase in IL-13, but not IL-12 release from P815 cells. Blocking antibodies against RANTES and CCR5 diminished RANTES induced IL-13 release. Furthermore, RANTES upregulated expression of PAR-1, PAR-2 and PAR-3 mRNAs, but enhanced only PAR-1 protein expression. At 1 ng/ml, RANTES can abolish tryptase induced IL-13 release, but enhance trypsin, tryptase and thrombin induced PAR-1, -2 and -4 expression. LY204002 abolished RANTES induced IL-13 release, indicating an Akt cell signaling pathway may be involved in the event. In conclusion, RANTES can stimulate IL-13 release from mast cells through a CCR5 and Akt cell signaling pathway dependent mechanism. It can also enhance trypsin, tryptase and thrombin-induced expression of PARs in mast cells. RANTES may contribute to modulation of IL-13 production and PAR expression in mast cells, through which participates in the mast cell related inflammation.
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ABSTRACT: Immune activation is a main driver of AIDS- and non-AIDS-linked morbidities in the course of HIV-1 infection. As CCR5, the main HIV-1 co-receptor, is not only a chemokine receptor but also a co-activation molecule expressed at the surface of T cells, it could be directly involved in this immune activation. To test this hypothesis, we measured by flow cytometry the mean number of CCR5 molecules at the surface of non-activated CD4(+) T cells (CCR5 density), which determines the intensity of CCR5 signalling, and the percentage of CD8(+) T cells over-expressing CD38 (CD38 expression), a major marker of immune activation, in the blood of 67 HIV-1-infected, non-treated individuals. CCR5 density was correlated with CD38 expression independently of viral load (P=0.016). CCR5 density remained unchanged after highly active anti-retroviral therapy (HAART) introduction or cessation, whereas CD38 expression decreased and increased, respectively. Moreover, pre-therapeutic CCR5 density was highly predictive (r=0.736, P<10(-4) ) of residual CD38 over-expression after 9 months of HAART. Hence, CCR5 might play an immunological role in HIV-1 infection as a driver of immune activation. This could explain why CCR5 antagonists may have an inhibitory effect on immune activation.Immunology 09/2012; 137(1):89-97. · 3.71 Impact Factor