Potent CCR3 Receptor Antagonist, SB328437, Suppresses Colonic Eosinophil Chemotaxis and Inflammation in the Winnie Murine Model of Spontaneous Chronic Colitis

Abstract

Eosinophils and their regulatory molecules have been associated with chronic intestinal inflammation and gastrointestinal dysfunctions; eosinophil accumulation in the gut is prominent in inflammatory bowel disease (IBD). The chemokine receptor CCR3 plays a pivotal role in local and systemic recruitment and activation of eosinophils. In this study, we targeted CCR3-ligand interactions with a potent CCR3 receptor antagonist, SB328437, to alleviate eosinophil-associated immunological responses in the Winnie model of spontaneous chronic colitis. Winnie and C57BL/6 mice were treated with SB328437 or vehicle. Clinical and histopathological parameters of chronic colitis were assessed. Flow cytometry was performed to discern changes in colonic, splenic, circulatory, and bone marrow-derived leukocytes. Changes to the serum levels of eosinophil-associated chemokines and cytokines were measured using BioPlex. Inhibition of CCR3 receptors with SB328437 attenuated disease activity and gross morphological damage to the inflamed intestines and reduced eosinophils and their regulatory molecules in the inflamed colon and circulation. SB328437 had no effect on eosinophils and their progenitor cells in the spleen and bone marrow. This study demonstrates that targeting eosinophils via the CCR3 axis has anti-inflammatory effects in the inflamed intestine, and also contributes to understanding the role of eosinophils as potential end-point targets for IBD treatment.

Transcriptomic analysis of differentially expressed genes in the Winnie mouse model of chronic colitis

“…Recent studies have shown that colitisassociated activation of neutrophils, macrophages, B-and T-cells, broblasts, endothelial cells and platelets, and hypoxic stress caused a down-regulation of mitochondrial proteins while pro-in ammatory proteins were known to be upregulated by immune cells, the colitis-associated epithelial cells, broblasts, endothelial cells and platelets contributed towards anti-in ammatory and wound healing-promoting proteins [45]. Further, there is an increase in eosinophils in IBD both in mice and in humans, which can be alleviated with anti-CCR3 receptor antagonists [20,46,47]. The fact that several of these alterations resemble abnormal motor capabilities in patients with IBD further exempli es that the Winnie mouse model is remarkably similar to human IBD.…”

Oxidative Stress-Induced HMGB1 Translocation in Myenteric Neurons Contributes to Neuropathy in Colitis

“…Slides were then mounted with DPX mounting media (Sigma-Aldrich #03989). A histological grading system was used to evaluate gross morphological damage using the following parameters: aberrant crypt architecture (score range, 0–3), crypt abscesses (0–3), leukocyte infiltration (0–3), epithelial damage (0–3), and ulceration (0–3); an average of 3 areas of 500 × 500 µm per section were analysed [ 4 , 5 ]. Slides were imaged using an Olympus BX53 microscope (Olympus Imaging, Sydney, NSW, Australia).…”

“…HMGB1 has emerged as an important alarmin to cellular stress involved in the pathophysiology of several diseases [ 3 ]. In conditions of cellular stress, the two HMGB1 nuclear localization sites are hyperacetylated, and HMGB1 translocates to the cellular cytoplasm, where it is released actively by leukocytes or passively by necrotic and necroptotic cells [ 4 ]. In the extracellular space, HMGB1 functions as a damage-associated molecular pattern (DAMP), acting as a direct chemoattractant via the C-X-C chemokine ligand 12 (CXCL12) and C-X-C chemokine receptor 4 (CXCR4) axis, as well as stimulating the release of pro-inflammatory mediators via toll-like receptors (TLR)-2 and TLR-4 expressed on nearby immune cells [ 2 ].…”

Cancer Immunotherapy: The Checkpoint between Chronic Colitis and Colorectal Cancer

“…Eosinophils are not only involved in inflammation but also induce alterations to the enteric nervous system and are linked with disease severity [ 69 ]. The chemokine receptor, CCR3 which plays a role in the recruitment and activation of eosinophils has been shown that its blockade via a CCR3 antagonist attenuates disease severity and morphological damage to inflamed intestinal tissues in the spontaneous model of chronic colitis ( Winnie mice) [ 70 ]. Similarly, in guinea pigs, intestinal inflammation/colitis caused following TNBS treatment results in increase of eosinophils at the site of inflammation.…”