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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.


Chemerin expression in human vessels: Representative photomicrographs show chemerin (green) in smooth muscle cells (*) and endothelium (˄) of human (A) saphenous vein (SV), mammary artery (MA), coronary artery (CA), and aorta (AO; all n=3 patients), with cell markers (red) smooth muscle alpha actin (SMαA) or von Willebrand factor (vWF) and autofluorescence in the 488‐nm channel (in blue). L denotes the lumen of the vessel and → expression in the adventitial layer of the MA. Scale bars=500 μm. B, Expression of mRNA levels of chemerin in human vessels and ASMCs are shown relative to expression in ASMCs and expressed as mean±SEM (n=5–10 patients). ASMCs indicates aortic smooth muscle cells.
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jah31763-fig-0001: Chemerin expression in human vessels: Representative photomicrographs show chemerin (green) in smooth muscle cells (*) and endothelium (˄) of human (A) saphenous vein (SV), mammary artery (MA), coronary artery (CA), and aorta (AO; all n=3 patients), with cell markers (red) smooth muscle alpha actin (SMαA) or von Willebrand factor (vWF) and autofluorescence in the 488‐nm channel (in blue). L denotes the lumen of the vessel and → expression in the adventitial layer of the MA. Scale bars=500 μm. B, Expression of mRNA levels of chemerin in human vessels and ASMCs are shown relative to expression in ASMCs and expressed as mean±SEM (n=5–10 patients). ASMCs indicates aortic smooth muscle cells.

Mentions: mRNA encoding chemerin, CMKLR1, and GPR1 and the corresponding proteins were widely expressed in human large conduit arteries and veins and in resistance vessels. Chemerin was present in the endothelium and smooth muscle medial layer, as defined by vWF and SMαA staining, respectively, of histologically normal human SV, MA, AO, and CA, as well as the adventitial layer of MA (Figure 1A). In sections of human LV, lung, and kidney, chemerin was localized to endothelial cells of small blood vessels and to endocardial endothelial cells, epithelial cells of the lung bronchioles, and tubules and endothelial cells in the kidney (Figure 2). Chemerin mRNA levels were similar in human SV, MA, CA, and AO and less abundant in ASMCs (Figure 1B).


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
Chemerin expression in human vessels: Representative photomicrographs show chemerin (green) in smooth muscle cells (*) and endothelium (˄) of human (A) saphenous vein (SV), mammary artery (MA), coronary artery (CA), and aorta (AO; all n=3 patients), with cell markers (red) smooth muscle alpha actin (SMαA) or von Willebrand factor (vWF) and autofluorescence in the 488‐nm channel (in blue). L denotes the lumen of the vessel and → expression in the adventitial layer of the MA. Scale bars=500 μm. B, Expression of mRNA levels of chemerin in human vessels and ASMCs are shown relative to expression in ASMCs and expressed as mean±SEM (n=5–10 patients). ASMCs indicates aortic smooth muscle cells.
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jah31763-fig-0001: Chemerin expression in human vessels: Representative photomicrographs show chemerin (green) in smooth muscle cells (*) and endothelium (˄) of human (A) saphenous vein (SV), mammary artery (MA), coronary artery (CA), and aorta (AO; all n=3 patients), with cell markers (red) smooth muscle alpha actin (SMαA) or von Willebrand factor (vWF) and autofluorescence in the 488‐nm channel (in blue). L denotes the lumen of the vessel and → expression in the adventitial layer of the MA. Scale bars=500 μm. B, Expression of mRNA levels of chemerin in human vessels and ASMCs are shown relative to expression in ASMCs and expressed as mean±SEM (n=5–10 patients). ASMCs indicates aortic smooth muscle cells.
Mentions: mRNA encoding chemerin, CMKLR1, and GPR1 and the corresponding proteins were widely expressed in human large conduit arteries and veins and in resistance vessels. Chemerin was present in the endothelium and smooth muscle medial layer, as defined by vWF and SMαA staining, respectively, of histologically normal human SV, MA, AO, and CA, as well as the adventitial layer of MA (Figure 1A). In sections of human LV, lung, and kidney, chemerin was localized to endothelial cells of small blood vessels and to endocardial endothelial cells, epithelial cells of the lung bronchioles, and tubules and endothelial cells in the kidney (Figure 2). Chemerin mRNA levels were similar in human SV, MA, CA, and AO and less abundant in ASMCs (Figure 1B).

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.