HISTAMINE-DENDRITIC CELLS INTERACTION: ROLE OF PKC

ALCAIN J; FUENTES F; GORI S; BORGE M; SALAMONE G; VERMEULEN M

Congreso; Reunión anual conjunta SAI-LASID-FAIC; 2015

SAI-LASID-FAIC

Background: dendritic cells (DCs) are able to present extracellular antigens associated with the molecules of the major histocompatibility complex class I (CMHI), which leads to activation of CD8+ T cells. Previously, we demonstrated that histamine (HIS) improves cross presentation of ovalbumin (OVA) by murine CDs, an effect that is dependent of the V-ATPase since it was inhibited in the presence of bafilomycin. The HIS acts through G-protein coupled receptors. The H1 receptor is associated with the Gq subunit, which involves PKC signaling. This pathway is related to the apoptotic process. Objective: Given this background, here we studied the modulation by the HIS of DCs apoptosis and the mechanisms involved. Materials and Methods: The assays were performed using DCs differentiated from bone marrow precursors of C57BL/6j mice, in the presence of recombinant granulocyte-macrophage colony stimulating factor (GM-CSF). DCs were exposed to HIS (0.1μM) and the PKC inhibitor (Go-6983; 1nM). Extracts for Western blot analysis were performed after 10 min of stimulation with different treatments. Apoptotic damage was induced by heat shock and apoptosis was evaluated 24 hours with Annexin-V+ propidium iodide. Results: HIS activates PKC pathway and decreases activation of procaspase 3, as seen by Western blot technique. Likewise, it also protects DCs apoptosis after heat shock (DCs 27%, HIS 14.20%), which appears to be partially reversed by inhibition of PKC (HIS inhib 17.89%). Conclusion: Our results demonstrate that the interaction with HIS activates the PKC signaling pathway and that this would protect DCs from entering apoptosis.