Ethanol promotes protease activated receptor 1: Chemokine (C-X-C motif) receptor 4 heteromerization and enhances thrombin-induced impairment of human lung endothelial cell barrier function.

Ethanol enhances the propensity of PAR1 and CXCR4 to form heteromers. Ethanol increases PAR1:CXCR4 heteromer expression in human lung microvascular endothelial cells (HULEC-5a). Ethanol enhances the efficacy of PAR1 to activate Gα upon thrombin stimulation in cells co-expressing CXCR4.

Chemokine receptor hetero-oligomers regulate monocyte chemotaxis.

It is known that stress influences immune cell function. The underlying molecular mechanisms are unclear. We recently reported that many chemokine receptors (CRs) heteromerize with α-adrenoceptors (α-ARs) through which CRs are regulated.

Effects of chemokine (C-C motif) receptor 2 and 3 antagonists in rat models of hemorrhagic shock.

Systemic concentrations of chemokine CCL2, an agonist at chemokine receptors CCR2/3/5, have been associated with hemodynamic instability after traumatic-hemorrhagic shock. We reported previously that the CCR2 antagonist INCB3284 prevents cardiovascular collapse and reduces fluid requirements after 30min of hemorrhagic shock (HS), whereas the CCR5 antagonist Maraviroc was ineffective. The effects of CCR3 blockade after HS are unknown and information on the therapeutic potential of INCB3284 after longer periods of HS and in HS models in the absence of fluid resuscitation (FR) is lacking.

α-adrenoceptor ligands inhibit chemokine receptor heteromerization partners of α-adrenoceptors via interference with heteromer formation.

We reported previously that α-adrenoceptor (α-AR) ligands inhibit chemokine receptor (CR) heteromerization partners of α-AR. The underlying mechanisms are unknown and in vivo evidence for such effects is missing. Utilizing CCR2 and α-AR as prototypical partners, we observed in recombinant systems and THP-1 cells that α-AR enhanced whereas its absence inhibited Gαi signaling of CCR2.

Heteromerization between α -adrenoceptor and chemokine (C-C motif) receptor 2 biases α -adrenoceptor signaling: Implications for vascular function.

Previously, we reported that chemokine (C-C motif) receptor 2 (CCR2) heteromerizes with α -adrenoceptor (α -AR) in leukocytes, through which α -AR controls CCR2. Whether such heteromers are expressed in human vascular smooth muscle cells (hVSMCs) is unknown. Bioluminescence resonance energy transfer confirmed formation of recombinant CCR2:α -AR heteromers.

The Chemokine (C-C Motif) Receptor 2 Antagonist INCB3284 Reduces Fluid Requirements and Protects From Hemodynamic Decompensation During Resuscitation From Hemorrhagic Shock.

Unlabelled: Clinical correlations suggest that systemic chemokine (C-C motif) ligand (CCL) 2 release may contribute to blood pressure regulation and the development of hemodynamic instability during the early inflammatory response to traumatic-hemorrhagic shock. Thus, we investigated whether blockade of the principal CCL2 receptor chemokine (C-C motif) receptor (CCR) 2 affects blood pressure in normal animals, and hemodynamics and resuscitation fluid requirements in hemorrhagic shock models.

Design: Randomized prospective treatment study.

α-adrenoceptors regulate chemokine receptor-mediated leukocyte migration via formation of heteromeric receptor complexes.

It is known that catecholamines regulate innate immune functions. The underlying mechanisms, however, are not well understood. Here we show that at least 20 members of the human chemokine receptor (CR) family heteromerize with one or more members of the α1-adrenergic receptor (AR) family in recombinant systems and that such heteromeric complexes are detectable in human monocytes and the monocytic leukemia cell line THP-1.

Chemokine receptor antagonists with α-adrenergic receptor blocker activity.

Objectives: Chemokine receptor antagonists are being explored for their therapeutic potential in various disease processes. As the chemokine (C-C motif) receptor 2 (CCR2) antagonist RS504393 is known to compete with ligand binding to α-adrenoceptors, we tested a panel of 10 CCR antagonists for interactions with α-adrenoceptors to evaluate potential cardiovascular activities and side-effect profiles.

Methods: The PRESTO-Tango β-arrestin recruitment assay was utilized to test whether the CCR antagonists interfere with α-AR activation upon stimulation with phenylephrine.

Class A G protein-coupled receptors assemble into functional higher-order hetero-oligomers.

Although class A seven-transmembrane helix (7TM) receptor hetero-oligomers have been proposed, information on the assembly and function of such higher-order hetero-oligomers is not available. Utilizing bioluminescence resonance energy transfer (BRET), bimolecular luminescence/fluorescence complementation (BiLC/BiFC), and BiLC/BiFC BRET in HEK293T cells, we provide evidence that chemokine (C-X-C motif) receptor 4, atypical chemokine receptor 3, α -adrenoceptor, and arginine vasopressin receptor 1A form hetero-oligomers composed of 2-4 different protomers. We show that hetero-oligomerization per se and ligand binding to individual protomers regulate agonist-induced coupling to the signaling transducers of interacting receptor partners.

Regulation of the thrombin/protease-activated receptor 1 axis by chemokine (CC motif) receptor 4.

The chemokine receptor CXCR4, a G protein-coupled receptor (GPCR) capable of heteromerizing with other GPCRs, is involved in many processes, including immune responses, hematopoiesis, and organogenesis. Evidence suggests that CXCR4 activation reduces thrombin/protease-activated receptor 1 (PAR1)-induced impairment of endothelial barrier function. However, the mechanisms underlying cross-talk between CXCR4 and PAR1 are not well-understood.

Natural and engineered chemokine (C-X-C motif) receptor 4 agonists prevent acute respiratory distress syndrome after lung ischemia-reperfusion injury and hemorrhage.

We compared therapeutic properties of natural and engineered chemokine (C-X-C motif) receptor 4 (CXCR4) agonists in a rat acute respiratory distress syndrome (ARDS) model utilizing the PaO/FiO-ratio as a clinically relevant primary outcome criterion. Ventilated rats underwent unilateral lung ischemia from t = 0-70 min plus hemorrhage to a mean arterial blood pressure (MAP) of 30 mmHg from t = 40-70 min, followed by reperfusion/fluid resuscitation until t = 300 min. Natural CXCR4 agonists (CXCL12, ubiquitin) and engineered CXCL12 variants (CXCL12, CXCL2, CXCL12K27A/R41A/R47A, CXCL12 (3-68)) were administered within 5 min of fluid resuscitation.

Characterization of heteromeric complexes between chemokine (C-X-C motif) receptor 4 and α-adrenergic receptors utilizing intermolecular bioluminescence resonance energy transfer assays.

Recently, we reported that chemokine (C-X-C motif) receptor 4 (CXCR4) heteromerizes with α-adrenergic receptors (AR) on the cell surface of vascular smooth muscle cells, through which the receptors cross-talk. Direct biophysical evidence for CXCR4:α-AR heteromers, however, is lacking. Here we utilized bimolecular luminescence/fluorescence complementation (BiLC/BiFC) combined with intermolecular bioluminescence resonance energy transfer (BRET) assays in HEK293T cells to evaluate CXCR4:α-AR heteromerization.