A C‐terminal CXCL8 peptide based on chemokine–glycosaminoglycan interactions reduces neutrophil adhesion and migration during inflammation

Abstract

Summary Leucocyte recruitment is critical during many acute and chronic inflammatory diseases. Chemokines are key mediators of leucocyte recruitment during the inflammatory response, by signalling through specific chemokine G‐protein‐coupled receptors (GPCRs). In addition, chemokines interact with cell‐surface glycosaminoglycans (GAGs) to generate a chemotactic gradient. The chemokine interleukin‐8/CXCL8, a prototypical neutrophil chemoattractant, is characterized by a long, highly positively charged GAG‐binding C‐terminal region, absent in most other chemokines. To examine whether the CXCL8 C‐terminal peptide has a modulatory role in GAG binding during neutrophil recruitment, we synthesized the wild‐type CXCL8 C‐terminal [CXCL8 (54–72)] (Peptide 1), a peptide with a substitution of glutamic acid (E) 70 with lysine (K) (Peptide 2) to increase positive charge; and also, a scrambled sequence peptide (Peptide 3). Surface plasmon resonance showed that Peptide 1, corresponding to the core CXCL8 GAG‐binding region, binds to GAG but Peptide 2 binding was detected at lower concentrations. In the absence of cellular GAG, the peptides did not affect CXCL8‐induced calcium signalling or neutrophil chemotaxis along a diffusion gradient, suggesting no effect on GPCR binding. All peptides equally inhibited neutrophil adhesion to endothelial cells under physiological flow conditions. Peptide 2, with its greater positive charge and binding to polyanionic GAG, inhibited CXCL8‐induced neutrophil transendothelial migration. Our studies suggest that the E70K CXCL8 peptide, may serve as a lead molecule for further development of therapeutic inhibitors of neutrophil‐mediated inflammation based on modulation of chemokine–GAG binding.

Alteration of chemokine production in bovine endometrial epithelial and stromal cells under heat stress conditions

“…To eliminate these bacteria, immune cells need to be recruited to the epithelial layer (Karstrup et al., 2017) and neutrophils play an important role in the elimination of bacteria, especially (Brodzki et al., 2014; Sheldon et al., 2014). Neutrophils in peripheral blood recognize the gradient of IL‐8 concentrations and are chemoattracted to the infection site (Martínez‐Burgo et al., 2019; Zachariae, 1993). In the present study, HS enhanced IL‐8 production in bovine endometrial stromal cells (Figure 3d) but did not affect it in endometrial epithelial cells (Figure 3b).…”

Targeting Chemokine—Glycosaminoglycan Interactions to Inhibit Inflammation

“…Furthermore, the peptides did not affect chemokine-GPCR binding. Only the E70K peptide showed the ability to inhibit CXCL8-mediated transendothelial migration of neutrophils (233).…”

“…This approach resulted in limited success with a number of compounds in clinical trials, but only two small molecule chemokine receptor antagonists on the market (for treatment of HIV and treatment of leukemia) (225)(226)(227). Since it is clear that also binding to GAGs is important for chemokine functioning in vivo, a few groups are investigating the inhibition of chemokine-GAG interactions (199,(228)(229)(230)(231)(232)(233).…”

Increased CCL24 and CXCL7 levels in the cerebrospinal fluid of patients with neurosyphilis

“…The AUCs of CSF CXCL13, CXCL8, and CXCL10 were all approximately 0.9 in a previous study, indicating that these chemokines are not only potential biomarkers as complementary diagnostic tools for neurosyphilis but may also be useful for monitoring therapeutic effects 8 . Interestingly, CXCL8, as CXCL7, was reported to reduce neutrophil adhesion and migration during inflammation, and thus plays a key role in the chemotactic activity of neutrophils 22 …”

“…8 Interestingly, CXCL8, as CXCL7, was reported to reduce neutrophil adhesion and migration during inflammation, and thus plays a key role in the chemotactic activity of neutrophils. 22 CCL24, also known as eotaxin-2, is a C-C motif-containing chemokine that facilitates eosinophil recruitment to sites of inflammatory responses to parasitic infections, as well as in allergic and autoimmune diseases, such as asthma and atopic dermatitis. 9 Increased serum or CSF CCL24 levels have been reported in patients with fibromyalgia syndrome, 23 neurodegenerative diseases, 24 Huntington's disease, 25 Listeria monocytogenes meningitis, 26 neuromyelitis optica, 27 and secondary progressive multiple sclerosis.…”