Multifaceted Roles of Cysteinyl Leukotrienes in Eliciting Eosinophil Granule Protein Secretion

Figure 1

CysLTs are intracrine signals regulating eosinophils’ IL-4 secretion by piecemeal degranulation.IL-4 release induced by IL-16, eotaxin, and RANTES is dependent on the intracrine action of lipid body-generated LTC₄. Inhibitors of 5-lypoxigenase (5-LO) and/or cysteinyl leukotriene receptors (cysLTRs) blocked intracellular LTC₄ production and consequently IL-4 release from eosinophils. The cross-linking of LIR7- or CD9-induced perinuclear-generated LTC₄, however IL-12 secretion induced by LIR7 or CD9 is independent of 5-LO metabolites. CysLT₁R = cysLT₁ receptor; cysLT₂R = cysLT₂ receptor, P2Y12R = purinergic P2Y12 receptor, and APLM = arachidonyl phospholipids and lipoxygenase machinery.