Introduction
Cendakimab is a recombinant, humanized IgG1 monoclonal antibody with high affinity and selectivity for IL-13. IL-13 is a key mediator of type 2 inflammation and contributes to eosinophil recruitment, epithelial barrier dysfunction, tissue remodeling, and fibrosis. Cendakimab prevents IL-13 from interacting with its two cognate receptors, IL-13Rα1 and IL-13Rα2, and is under clinical investigation for eosinophilic esophagitis (EoE), eosinophilic gastritis (EoG), and eosinophilic duodenitis (EoD) which are marked by elevated levels of IL-13. [1, 2]
Aims & Methods
Our primary objective was to investigate the role of IL-13Rα2, which has thus far primarily been considered to be a decoy receptor that lacks signaling ability [3 - 6], in fibroblast function. Further, we wanted to understand cendakimab’s mechanism of action as it relates to human fibroblasts.
A human melanoma cell line model (A375) and cultures of primary human esophageal and dermal fibroblasts were stimulated with recombinant IL-13 in the presence or absence of cendakimab before assessing the induction of the Activator Protein-1 (AP-1) transcription factor, which has been described as a master regulator of fibrotic disease [7]. AP-1 was measured using a colorimetric enzyme-linked immunosorbent assay (ELISA). Flow cytometry was employed to determine the cell surface expression of IL-13Rα1 and IL-13Rα2. To assess the functional response in IL-13 stimulated fibroblasts, secreted proteins were quantified by mesoscale discovery (MSD) immunoassays and gene expression changes were investigated using quantitative PCR (qPCR).
Results
Results show that IL-13Rα2 is not a decoy but a signaling cytokine receptor whose stimulation with IL-13 leads to the induction of AP-1 in A375 cells which natively express IL-13Rα2. This signaling is specific to IL-13Rα2 as AP-1 induction was not observed using A375 cells in which the parental gene IL13RA2 has been knocked-out and which also lack expression of IL-13Rα1. Cendakimab blocks IL-13 induced AP-1 production in A375 cells.
Similar results were also noted in primary human esophageal and dermal fibroblasts. Cendakimab inhibits IL-13 induced AP-1 signaling with a potency of 2.9nM (A375) and 1.7nM or 2.7nM in esophageal or dermal fibroblasts, respectively.
IL-13 stimulation of primary human esophageal and dermal fibroblasts led to the production of the cytokine IL-6, the monocyte chemoattractant protein-1 (MCP-1, also known as CCL2), hepatocyte growth factor (HGF), as well as extracellular matrix proteins periostin and tenascin C, suggesting these factors may be controlled by AP-1. IL-6 and MCP-1 have both been described as pro-fibrotic mediators under chronic inflammatory conditions [8, 9], HGF is a known regulator of epithelial-mesenchymal transition (EMT) driving tissue fibrosis [10], and periostin and its interacting partner tenascin C have been shown to mark areas of fibrosis as well as being directly involved in eosinophil infiltration [11]. Cendakimab treatment inhibited the production of all these proteins in primary human esophageal and dermal fibroblasts.
Conclusion
These experiments confirm that IL-13Rα2 is a signaling cytokine receptor whose engagement leads to the pro-fibrotic activation of primary human fibroblasts. Cendakimab’s potent ability to attenuate this behavior has important implications for its potential value in targeting the fibrostenotic aspects of esophageal dysfunction in EoE [12] and addressing the unmet need of patients suffering from this chronic and progressive disease.
References
[1] Tripp CS, et al. Adv Ther. 2017;34:1364-1381.
[2] Hirano I, et al. Gastroenterology. 2019;156:592-603.
[3] Donaldson DD et al. J Immunol. 1998;161(5):2317-24.
[4] Bernard J et al. Lab Invest. 2001;81:1223-1231.
[5] Wynn TA et al. Lab Invest. 1998;78:591-602.
[6] Wood N et al. J Exp Med. 2003;197:703-709.
[7] Werning G et al. PNAS. 2017;114(18):4757-4762.
[8] Li Y et al. Int J Biol Sci. 2022; 18(4):5405-5414.
[9] Gharaee-Kermani M et al. J Biol Chem. 1996; 271(30):17779-84.
[10] Zavadil J et al. Oncogene. 24:5764-5774.
[11] Blanchard C et al. Mucosal Immunol. 2008; 1(4):289-296.
[12] Armbruster-Lee J et al. JLB. 2018;104(1):31-40.
Disclosure
The authors are employees and shareholders of Bristol Myers Squibb. Bristol Myers Squibb provided the funding for this work.