Heteromerization between α_1B‐adrenoceptor and chemokine (C‐C motif) receptor 2 biases α_1B‐adrenoceptor signaling: Implications for vascular function

Abstract

Previously, we reported that chemokine (C‐C motif) receptor 2 (CCR2) heteromerizes with α1B‐adrenoceptor (α1B‐AR) in leukocytes, through which α1B‐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:α1b‐AR heteromers. Proximity ligation assays detected CCR2:α1B‐AR heteromers in hVSMCs and human mesenteric arteries. CCR2:α1B‐AR heteromerization per se enhanced α1B‐AR‐mediated Gαq‐coupling. Chemokine (C‐C motif) ligand 2 (CCL2) binding to CCR2 inhibited Gαq activation via α1B‐AR, cross‐recruited β‐arrestin to and induced internalization of α1B‐AR in recombinant systems and in hVSMCs. Our findings suggest that CCR2 within CCR2:α1B‐AR heteromers biases α1B‐AR signaling and provide a mechanism for previous observations suggesting a role for CCL2/CCR2 in the regulation of cardiovascular function.

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

“…As such, this study does not provide information on physiological and molecular mechanisms by which CCR3 and CCR2 blockade affect resuscitation fluid requirements and on the possible side effect profile of the drugs. Based on previous observations indicating that CCL2 and CCR2 are involved in the regulation of vascular function, however, it appears likely that direct effects of CCR2 blockade on endothelial or vascular smooth muscle function mediate the observed effects [ 16 – 18 ]. We believe that the profound fluid sparing effects of INCB3284 that we observed in the present study further justify its detailed pharmacological characterization in small and large animal models, and the assessment of its side effect profile as a drug candidate to improve fluid resuscitation from traumatic-hemorrhagic shock.…”

G protein activation via chemokine (C‐X‐C motif) receptor 4 and α1b‐adrenoceptor is ligand and heteromer‐dependent

“…Bioluminescence resonance energy transfer (BRET) assays were performed as described previously [25,[28][29][30]. In brief, HEK293T cells were seeded in 24-well plates and transfected using TransIT-2020 Transfection Reagent (Mirus Bio, Madison, WI, USA).…”