The resolvin D1 receptor GPR32 transduces inflammation resolution and atheroprotection
Hildur Arnardottir, … , Göran K. Hansson, Magnus Bäck
Hildur Arnardottir, … , Göran K. Hansson, Magnus Bäck
Published October 26, 2021
Citation Information: J Clin Invest. 2021;131(24):e142883. https://doi.org/10.1172/JCI142883.
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Research Article Cardiology Inflammation

The resolvin D1 receptor GPR32 transduces inflammation resolution and atheroprotection

Abstract

Chronic inflammation is a hallmark of atherosclerosis and results from an imbalance between proinflammatory and proresolving signaling. The human GPR32 receptor, together with the ALX/FPR2 receptor, transduces biological actions of several proresolving mediators that stimulate resolution of inflammation. However, since no murine homologs of the human GPR32 receptor exist, comprehensive in vivo studies are lacking. Using human atherosclerotic lesions from carotid endarterectomies and creating a transgenic mouse model expressing human GPR32 on a Fpr2×ApoE double-KO background (hGPR32myc×Fpr2–/–×Apoe–/–), we investigated the role of GPR32 in atherosclerosis and self-limiting acute inflammation. GPR32 mRNA was reduced in human atherosclerotic lesions and correlated with the immune cell markers ARG1, NOS2, and FOXP3. Atherosclerotic lesions, necrotic core, and aortic inflammation were reduced in hGPR32mycTg×Fpr2–/–×Apoe–/– transgenic mice as compared with Fpr2–/–×Apoe–/– nontransgenic littermates. In a zymosan-induced peritonitis model, the hGPR32mycTg×Fpr2–/–×Apoe–/– transgenic mice had reduced inflammation at 4 hours and enhanced proresolving macrophage responses at 24 hours compared with nontransgenic littermates. The GPR32 agonist aspirin-triggered resolvin D1 (AT-RvD1) regulated leukocyte responses, including enhancing macrophage phagocytosis and intracellular signaling in hGPR32mycTg×Fpr2–/–×Apoe–/– transgenic mice, but not in Fpr2–/–×Apoe–/– nontransgenic littermates. Together, these results provide evidence that GPR32 regulates resolution of inflammation and is atheroprotective in vivo.

Authors

Hildur Arnardottir, Silke Thul, Sven-Christian Pawelzik, Glykeria Karadimou, Gonzalo Artiach, Alessandro L. Gallina, Victoria Mysdotter, Miguel Carracedo, Laura Tarnawski, April S. Caravaca, Roland Baumgartner, Daniel F.J. Ketelhuth, Peder S. Olofsson, Gabrielle Paulsson-Berne, Göran K. Hansson, Magnus Bäck

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Figure 2

Generation of a new mouse strain expressing a human GPR32 Tg on an Apoe–/–×Fpr2–/– double-KO background.

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Generation of a new mouse strain expressing a human GPR32 Tg on an Apoe–...
(A) Schematics of the vector construction containing the hGPR32(ORF011088)/Myc Tg. (B) TLA sequence coverage across the mouse genome from an hGPR32mycTg×Fpr2–/–×Apoe–/– mouse showing the different chromosomes on the y axis and the chromosomal position on the x axis. The red circle indicates the Tg integration site. (C) Human GPR32 mRNA expression in different mouse tissues (n = 5). (D) Flow cytometry histogram (representative of n = 3) showing GPR32 expression in naive whole blood from Fpr2–/–×Apoe–/– (dark gray) and hGPR32mycTg×Fpr2–/–×Apoe–/– (light blue) mice (left) and differential expression of hGPR32myc in PBMC (purple) and neutrophil (dark blue) cell subsets (right). Isotype control cells are shown in light gray. (E) TNF-α levels in supernatants of LPS-stimulated (100 ng/mL, 24 hours) BMDMs from Fpr2–/–×Apoe–/– (n = 4, white box) and hGPR32mycTg×Fpr2–/–×Apoe–/– (n = 3, black box) mice. Results are expressed as median with minimum to maximum bars. *P < 0.05 between genotypes using Student’s unpaired t test.