Research Article Cross-Linking Mast Cell Specific Gangliosides Stimulates the Release of Newly Formed Lipid Mediators and Newly Synthesized Cytokines Edismauro Garcia Freitas Filho, 1 Elaine Zayas Marcelino da Silva, 1 Camila Ziliotto Zanotto, 2 Constance Oliver, 1 and Maria Célia Jamur 1 1 Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeir˜ ao Preto Medical School, University of S˜ ao Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeir˜ ao Preto, SP, Brazil 2 Department of Pharmacology, Ribeir˜ ao Preto Medical School, University of S˜ ao Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeir˜ ao Preto, SP, Brazil Correspondence should be addressed to Maria C´ elia Jamur; mjamur@fmrp.usp.br Received 25 April 2016; Accepted 13 July 2016 Academic Editor: Dianne Cooper Copyright © 2016 Edismauro Garcia Freitas Filho et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mast cells are immunoregulatory cells that participate in infammatory processes. Cross-linking mast cell specifc GD1b derived gangliosides by mAbAA4 results in partial activation of mast cells without the release of preformed mediators. Te present study examines the release of newly formed and newly synthesized mediators following ganglioside cross-linking. Cross-linking the gangliosides with mAbAA4 released the newly formed lipid mediators, prostaglandins D 2 and E 2 , without release of leukotrienes B 4 and C 4 . Te efect of cross-linking these gangliosides on the activation of enzymes in the arachidonate cascade was then investigated. Ganglioside cross-linking resulted in phosphorylation of cytosolic phospholipase A 2 and increased expression of cyclooxygenase- 2. Translocation of 5-lipoxygenase from the cytosol to the nucleus was not induced by ganglioside cross-linking. Cross-linking of GD1b derived gangliosides also resulted in the release of the newly synthesized mediators, interleukin-4, interleukin-6, and TNF- . Te efect of cross-linking the gangliosides on the MAP kinase pathway was then investigated. Cross-linking the gangliosides induced the phosphorylation of ERK1/2, JNK1/2, and p38 as well as activating both NFB and NFAT in a Syk-dependent manner. Terefore, cross-linking the mast cell specifc GD1b derived gangliosides results in the activation of signaling pathways that culminate with the release of newly formed and newly synthesized mediators. 1. Introduction Gangliosides are sialic acid containing glycosphingolipids that are present in the outer leafet of the plasma membrane as well as in the membranes of some organelles [1, 2]. Gangliosides play a role in diverse physiological processes including growth, diferentiation, cell-cell interactions, and cell signaling. Tey are also involved in many pathological processes, acting as receptors for viruses and toxins, and are implicated in tumor progression, atherosclerosis, and neurodegenerative disorders [3]. Gangliosides are present on the surface of mast cells and are critical for mast cell function [1]. Mast cells are multifunctional immune cells that participate in various biological events, such as infammation and allergy. Mast cell functions are directly related to their activation and subse- quent release of biologically active mediators [4, 5]. Mast cell activation via the high afnity IgE receptor (FcRI) is the best characterized form of activation. It occurs when multi- valent antigens cross-link antigen-specifc immunoglobulin E (IgE) bound to FcRI on the mast cell surface. Cross- linking FcRI initiates a signal transduction cascade that is dependent on the tyrosine kinase Syk [6]. Tis activation results in the release of three classes of mediators: pre- formed mediators such as histamine, proteases, cytokines, and enzymes; newly formed lipid mediators which are Hindawi Publishing Corporation Mediators of Inflammation Volume 2016, Article ID 9160540, 10 pages http://dx.doi.org/10.1155/2016/9160540