Soluble CD13 induces inflammatory arthritis by activating the bradykinin receptor B1
Pei-Suen Tsou, … , David A. Fox, M. Asif Amin
Pei-Suen Tsou, … , David A. Fox, M. Asif Amin
Published April 19, 2022
Citation Information: J Clin Invest. 2022;132(11):e151827. https://doi.org/10.1172/JCI151827.
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Research Article Autoimmunity

Soluble CD13 induces inflammatory arthritis by activating the bradykinin receptor B1

Abstract

CD13, an ectoenzyme on myeloid and stromal cells, also circulates as a shed, soluble protein (sCD13) with powerful chemoattractant, angiogenic, and arthritogenic properties, which require engagement of a G protein–coupled receptor (GPCR). Here we identify the GPCR that mediates sCD13 arthritogenic actions as the bradykinin receptor B1 (B1R). Immunofluorescence and immunoblotting verified high expression of B1R in rheumatoid arthritis (RA) synovial tissue and fibroblast-like synoviocytes (FLSs), and demonstrated binding of sCD13 to B1R. Chemotaxis, and phosphorylation of Erk1/2, induced by sCD13, were inhibited by B1R antagonists. In ex vivo RA synovial tissue organ cultures, a B1R antagonist reduced secretion of inflammatory cytokines. Several mouse arthritis models, including serum transfer, antigen-induced, and local innate immune stimulation arthritis models, were attenuated in Cd13–/– and B1R–/– mice and were alleviated by B1R antagonism. These results establish a CD13/B1R axis in the pathogenesis of inflammatory arthritis and identify B1R as a compelling therapeutic target in RA and potentially other inflammatory diseases.

Authors

Pei-Suen Tsou, Chenyang Lu, Mikel Gurrea-Rubio, Sei Muraoka, Phillip L. Campbell, Qi Wu, Ellen N. Model, Matthew E. Lind, Sirapa Vichaikul, Megan N. Mattichak, William D. Brodie, Jonatan L. Hervoso, Sarah Ory, Camila I. Amarista, Rida Pervez, Lucas Junginger, Mustafa Ali, Gal Hodish, Morgan M. O’Mara, Jeffrey H. Ruth, Aaron M. Robida, Andrew J. Alt, Chengxin Zhang, Andrew G. Urquhart, Jeffrey N. Lawton, Kevin C. Chung, Tristan Maerz, Thomas L. Saunders, Vincent E. Groppi, David A. Fox, M. Asif Amin

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Figure 4

B1R antagonist inhibits sCD13-mediated MN migration, FLS signaling, and cytokine production.

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B1R antagonist inhibits sCD13-mediated MN migration, FLS signaling, and ...
(A) SSR240612 (n = 21) significantly inhibited sCD13-induced MN migration (n = 21). DABK-induced MN migration (n = 20) was also inhibited by SSR240612 (n = 20), suggesting that DABK and sCD13 are 2 ligands of B1R. PBS (n = 10) was used as a negative control. n = number of wells. HPF, high-power fields. (B) Another B1R inhibitor, R715 (n = 4), also significantly inhibited sCD13-induced MN migration (n = 4). Lipopolysaccharide (LPS, n = 3) and PBS (n = 3) were used as positive and negative controls, respectively. n = number of assays. (C) sCD13- or DABK-stimulated phospho-Erk1/2 was significantly reduced by SSR240612 in RA FLSs from 4 different patients. (D) Quantification of Western blots. n = number of blots. (E) RA FLSs transfected with a B1R-silencing construct showed that sCD13-stimulated Erk1/2 phosphorylation was markedly decreased in comparison with scrambled RNA. (F) B1R inhibitor SSR240612 inhibited cytokines MCP-1/CCL2 and IL-6 in RA ST. Dexamethasone was used as a control for cytokine inhibition. n = number of replicates from 3 RA patients. Results represent the mean ± SD. *P < 0.05. Significance was determined by Kruskal-Wallis test (A) and 1-way ANOVA (B, D, and F). SSR, SSR240612; NS, nonstimulated; Dex, dexamethasone.