CysLT2 receptors interact with CysLT1 receptors and down-modulate cysteinyl leukotriene–dependent mitogenic responses of mast cells

Abstract

Cysteinyl leukotrienes (cys-LTs) induce inflammation through 2 G protein–coupled receptors (GPCRs), CysLT1 and CysLT2, which are coexpressed by most myeloid cells. Cys-LTs induce proliferation of mast cells (MCs), transactivate c-Kit, and phosphorylate extracellular signal-regulated kinase (ERK). Although MCs express CysLT2, their responses to cys-LTs are blocked by antagonists of CysLT1. We demonstrate that CysLT2 interacts with CysLT1, and that knockdown of CysLT2 increases CysLT1 surface expression and CysLT1-dependent proliferation of cord blood–derived human MCs (hMCs). Cys-LT–mediated responses were absent in MCs from mice lacking CysLT1 receptors, but enhanced by the absence of CysLT2 receptors. CysLT1 and CysLT2 receptors colocalized to the plasma membranes and nuclei of a human MC line, LAD2. Antibody-based fluorescent lifetime imaging microscopy confirmed complexes containing both receptors based on fluorescence energy transfer. Negative regulation of CysLT1-induced mitogenic signaling responses of MCs by CysLT2 demonstrates physiologically relevant functions for GPCR heterodimers on primary cells central to inflammation.

Phenotype-based Discovery of 2-[(E)-2-(Quinolin-2-yl)vinyl]phenol as a Novel Regulator of Ocular Angiogenesis

“…Cysteinyl leukotrienes have been reported previously to up-regulate ERK phosphorylation (38,39). Here we show that drug treatment with quininib inhibits LTD 4 -induced phospho-ERK up-regulation, which is completely blocked by the more downstream MEK 1/2 inhibitor TAK-733.…”

“…CysLT 2 and CysLT 1 are expressed in the murine retina, and exogenous cysLTs are sufficient to induce retinal edema (37). Here quininib inhibits known cysteinyl leukotriene receptor signaling pathways, reducing ERK phosphorylation in response to leukotriene D4 agonism (38,39). In summary, from unbiased chemical screens, we advance prior reports on cysLTs and demonstrate that a CysLT 1-2 antagonist significantly attenuates angiogenesis in the eye.…”

“…Recently montelukast has been reported to reduce neuroinflammation in an aged rat model, acting via inhibition of a separate cysteinyl leukotriene receptor, GPR17 (56), and a fourth cysteinyl leukotriene receptor, GPR99, has been proposed (26). In genetic loss-of function models, cysteinyl leukotriene receptors demonstrate cognate compensatory up-regulation (37,39,57). Thus, there are exciting future opportunities to decipher the cysLT receptors exhibiting co-regulatory expression to understand the underlying control mechanisms and to determine the combinations of cysLT receptors that regulate physiological phenotypes.…”

GPR17 is a negative regulator of the cysteinyl leukotriene 1 receptor response to leukotriene D 4

“…In addition, 1321N1 cell clones stably expressing mouse GPR17 did not respond to 100 M of UDP-glucose. Since heterodimerization of G protein-coupled receptors modulates expression and/or function either negatively (36,37) or positively (38,39) in various transfectants, we considered the possibility that GPR17 may associate with CysLT 1 R to control its calcium signaling function. Here we show that GPR17 may function as a negative regulator for the CysLT 1 R response to LTD 4 not only in cotransfection of transformed cells but also constitutively in primary cells in which its knockdown resulted in increased membrane expression and LTD 4 -mediated function of CysLT 1 R. We provide physiologic evidence for this regulatory role of GPR17 by demonstrating that the vascular leak following IgEdependent, mast cell-mediated passive cutaneous anaphylaxis (PCA) is significantly increased in GPR17-deficient mice and that this response is blocked by administration of a CysLT 1 R antagonist.…”

The CysLT1 Ligand Leukotriene D4 Supports α4β1- and α5β1-Mediated Adhesion and Proliferation of CD34+ Hematopoietic Progenitor Cells

“…The role and function of CysLT 2 is not completely understood. This receptor may also activate G i/o signaling pathways, although recent studies suggest that CysLT 2 interacts with CysLT 1 on the cell surface, resulting in the formation of heterodimers and eventually in the attenuation of CysLT 1 -mediated effects (16).…”