Limits...
Chemerin Elicits Potent Constrictor Actions via Chemokine ‐ Like Receptor 1 ( CMKLR 1), not G ‐ Protein ‐ Coupled Receptor 1 ( GPR 1), in Human and Rat Vasculature

View Article: PubMed Central - PubMed

ABSTRACT

Background: Circulating levels of chemerin are significantly higher in hypertensive patients and positively correlate with blood pressure. Chemerin activates chemokine‐like receptor 1 (CMKLR1 or ChemR23) and is proposed to activate the “orphan” G‐protein‐coupled receptor 1 (GPR1), which has been linked with hypertension. Our aim was to localize chemerin, CMKLR1, and GPR1 in the human vasculature and determine whether 1 or both of these receptors mediate vasoconstriction.

Methods and results: Using immunohistochemistry and molecular biology in conduit arteries and veins and resistance vessels, we localized chemerin to endothelium, smooth muscle, and adventitia and found that CMKLR1 and GPR1 were widely expressed in smooth muscle. C9 (chemerin149–157) contracted human saphenous vein (pD2=7.30±0.31) and resistance arteries (pD2=7.05±0.54) and increased blood pressure in rats by 9.1±1.0 mm Hg at 200 nmol. Crucially, these in vitro and in vivo vascular actions were blocked by CCX832, which we confirmed to be highly selective for CMKLR1 over GPR1. C9 inhibited cAMP accumulation in human aortic smooth muscle cells and preconstricted rat aorta, consistent with the observed vasoconstrictor action. Downstream signaling was explored further and, compared to chemerin, C9 showed a bias factor=≈5000 for the Gi protein pathway, suggesting that CMKLR1 exhibits biased agonism.

Conclusions: Our data suggest that chemerin acts at CMKLR1, but not GPR1, to increase blood pressure. Chemerin has an established detrimental role in metabolic syndrome, and these direct vascular actions may contribute to hypertension, an additional risk factor for cardiovascular disease. This study provides proof of principle for the therapeutic potential of selective CMKLR1 antagonists.

No MeSH data available.


Functional activity of (●) chemerin, (▼) C9 and (♦) C13 at heterologously expressed CMKLR1 and GPR1. Potencies of peptides were determined from measurements of inhibition of cAMP accumulation through CMKLR1 (A) and β‐arrestin recruitment through CMKLR1 (B) and GPR1 (C). Responses are shown as % of the maximal response to C13 and show mean±SEM (n=3–9 independent replicates). Calculated functional parameters are presented in Table 1. CMKLR1 indicates chemokine‐like receptor 1; GPR1, G‐protein‐coupled receptor 1.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5121526&req=5

jah31763-fig-0007: Functional activity of (●) chemerin, (▼) C9 and (♦) C13 at heterologously expressed CMKLR1 and GPR1. Potencies of peptides were determined from measurements of inhibition of cAMP accumulation through CMKLR1 (A) and β‐arrestin recruitment through CMKLR1 (B) and GPR1 (C). Responses are shown as % of the maximal response to C13 and show mean±SEM (n=3–9 independent replicates). Calculated functional parameters are presented in Table 1. CMKLR1 indicates chemokine‐like receptor 1; GPR1, G‐protein‐coupled receptor 1.

Mentions: Activities of full‐length chemerin and C9 were compared in downstream signaling assays. The C‐terminal fragment C13 was included to further investigate a trend of biased signaling. In cell‐based functional assays with CMKLR1, chemerin, C9, and C13 exhibited comparable maximum responses (Table 1). C‐terminal fragments, C9 and C13 (pD2=9.39±0.09 and 9.12±0.12, respectively) were more potent than chemerin (pD2=8.45±0.10) at inhibiting forskolin‐evoked cAMP accumulation (Figure 7A). However, compared to chemerin (pD2=9.37±0.05), C9 and C13 were less potent (pD2=7.09±0.06, and 7.15±0.04, respectively) at recruiting β‐arrestin (Figure 7B). Using chemerin as the reference endogenous ligand, bias analysis confirmed that the C‐terminal fragments had a bias factor of ≈3000 to 5000 for inhibition of cAMP accumulation compared to β‐arrestin recruitment (Table 2).


Chemerin Elicits Potent Constrictor Actions via Chemokine ‐ Like Receptor 1 ( CMKLR 1), not G ‐ Protein ‐ Coupled Receptor 1 ( GPR 1), in Human and Rat Vasculature
Functional activity of (●) chemerin, (▼) C9 and (♦) C13 at heterologously expressed CMKLR1 and GPR1. Potencies of peptides were determined from measurements of inhibition of cAMP accumulation through CMKLR1 (A) and β‐arrestin recruitment through CMKLR1 (B) and GPR1 (C). Responses are shown as % of the maximal response to C13 and show mean±SEM (n=3–9 independent replicates). Calculated functional parameters are presented in Table 1. CMKLR1 indicates chemokine‐like receptor 1; GPR1, G‐protein‐coupled receptor 1.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121526&req=5

jah31763-fig-0007: Functional activity of (●) chemerin, (▼) C9 and (♦) C13 at heterologously expressed CMKLR1 and GPR1. Potencies of peptides were determined from measurements of inhibition of cAMP accumulation through CMKLR1 (A) and β‐arrestin recruitment through CMKLR1 (B) and GPR1 (C). Responses are shown as % of the maximal response to C13 and show mean±SEM (n=3–9 independent replicates). Calculated functional parameters are presented in Table 1. CMKLR1 indicates chemokine‐like receptor 1; GPR1, G‐protein‐coupled receptor 1.
Mentions: Activities of full‐length chemerin and C9 were compared in downstream signaling assays. The C‐terminal fragment C13 was included to further investigate a trend of biased signaling. In cell‐based functional assays with CMKLR1, chemerin, C9, and C13 exhibited comparable maximum responses (Table 1). C‐terminal fragments, C9 and C13 (pD2=9.39±0.09 and 9.12±0.12, respectively) were more potent than chemerin (pD2=8.45±0.10) at inhibiting forskolin‐evoked cAMP accumulation (Figure 7A). However, compared to chemerin (pD2=9.37±0.05), C9 and C13 were less potent (pD2=7.09±0.06, and 7.15±0.04, respectively) at recruiting β‐arrestin (Figure 7B). Using chemerin as the reference endogenous ligand, bias analysis confirmed that the C‐terminal fragments had a bias factor of ≈3000 to 5000 for inhibition of cAMP accumulation compared to β‐arrestin recruitment (Table 2).

View Article: PubMed Central - PubMed

ABSTRACT

Background: Circulating levels of chemerin are significantly higher in hypertensive patients and positively correlate with blood pressure. Chemerin activates chemokine‐like receptor 1 (CMKLR1 or ChemR23) and is proposed to activate the “orphan” G‐protein‐coupled receptor 1 (GPR1), which has been linked with hypertension. Our aim was to localize chemerin, CMKLR1, and GPR1 in the human vasculature and determine whether 1 or both of these receptors mediate vasoconstriction.

Methods and results: Using immunohistochemistry and molecular biology in conduit arteries and veins and resistance vessels, we localized chemerin to endothelium, smooth muscle, and adventitia and found that CMKLR1 and GPR1 were widely expressed in smooth muscle. C9 (chemerin149–157) contracted human saphenous vein (pD2=7.30±0.31) and resistance arteries (pD2=7.05±0.54) and increased blood pressure in rats by 9.1±1.0 mm Hg at 200 nmol. Crucially, these in vitro and in vivo vascular actions were blocked by CCX832, which we confirmed to be highly selective for CMKLR1 over GPR1. C9 inhibited cAMP accumulation in human aortic smooth muscle cells and preconstricted rat aorta, consistent with the observed vasoconstrictor action. Downstream signaling was explored further and, compared to chemerin, C9 showed a bias factor=≈5000 for the Gi protein pathway, suggesting that CMKLR1 exhibits biased agonism.

Conclusions: Our data suggest that chemerin acts at CMKLR1, but not GPR1, to increase blood pressure. Chemerin has an established detrimental role in metabolic syndrome, and these direct vascular actions may contribute to hypertension, an additional risk factor for cardiovascular disease. This study provides proof of principle for the therapeutic potential of selective CMKLR1 antagonists.

No MeSH data available.