Mouse Anti Human Annexin A1 Hybridoma [DQUD-BOYB2-4]

Mast cells (MCs) participate in all stages of skin healing and one of their mediators is the Annexin A1 protein (AnxA1), linked to inflammation, proliferation, migration and apoptosis processes, but not studied in thermal burns yet. Therefore, our objectives were to evaluate the behavior of MCs and AnxA1 in a second degree burn model, treated or not with silver sulfadiazine 1% (SDP 1%) and associated to macrophages quantification and cytokines dosages. MCs counts showed few cells in the early stages of repair but increased MCs in the final phases in the untreated group. The normal skin presented numerous tryptase-positive MCs that were reduced after burning in all analyzed periods. Differently, few chymasepositive MCs were observed in the early stages of healing, however, increased chymasepositive MCs were found at the final phase in the untreated group. MCs also showed high immunoreactivity for AnxA1 on day 3 in both groups. In the tissue there was a strong protein expression in the early stages of healing, but in the final phases only in the SDP treated animals. TNF-alpha, IL-1 beta, IL-6, IL-10 and MCP-1 levels and macrophages quantification were increased in inflammation and reepithelialization phases. Reduced IL-1 beta, IL-6 and IL-10 levels and numerous macrophages occurred in the treated animals during tissue repair. Our results indicate modulation in the profile of MCs and AnxA1expression during healing by the treatment with SDP 1%, pointing them as targets for therapeutic interventions on skin burns.

Annexin A1 (AnxA1) is an important anti-inflammatory mediator during granulocytic differentiation in all trans-retinoic acid (ATRA) treated acute promyelocytic leukemic (APL) cells. Dexamethasone has been used successfully to prevent complications in ATRA-treated APL patients, although its mechanism of action is still not clear. In the present study, we have examined the effect of dexamethasone on the modulation of AnxA1 in ATRA-APL NB4 (ATRA-NB4) cells, ATRA-NB4 cells-derived microparticles (MPs) and its role during cellcell interaction between ATRA-NB4 cells and endothelial cells. Our results have shown that dexamethasone can inhibit the percentage of ATRA-NB4 cells expressing surface AnxA1 and its receptor FPR2/ALX in a time-dependent manner based on flow cytometric analysis. However, dexamethasone treatment of ATRA-NB4 cells has no significant effect on the level of AnxA1 mRNA, the total cellular level of AnxA1 protein or the release of AnxA1 from these cells, as determined by RT-PCR, Western blotting, and ELISA, respectively. Further studies demonstrate that dexamethasone is able to significantly inhibit the adhesion of ATRA-NB4 cells to endothelial cells, and this anti-adhesive effect can be inhibited if the cells were pre-treated with a neutralizing antibody specific for AnxA1. Finally, dexamethasone also enhances the release of AnxA1-containing MPs from ATRA-NB4 cells which can in turn prevent the adhesion of the ATRA-NB4 cells to endothelial cells. We conclude that biologically active AnxA1 originating from dexamethasone-treated ATRA-APL cells and their MPs plays an anti-adhesive effect and this contributes to inhibit the adhesion of ATRA-APL cell to endothelial cells. J. Cell. Biochem. 114: 551557, 2013. (C) 2012 Wiley Periodicals, Inc.