Humanized forms of the CXCR1/CXCR2 antagonist, bovine CXCL8(3–74)K11R/G31P, effectively block ELR–CXC chemokine activity and airway endotoxemia pathology

Feeding synthetic zeolite to transition dairy cows alters neutrophil gene expression

Synthetic zeolites are used to control the availability of dietary minerals (e.g., Ca, Mg, and P) in dairy cows. Due to calcium demand increasing with lactation onset, most cows become hypocalcemic immediately postpartum, which likely contributes to poorer immune function because calcium is important for immune cell signaling. To overcome postpartum hypocalcemia, we fed transition cows synthetic zeolite A (sodium aluminosilicate) precalving and hypothesized that it would alter calcium and thus neutrophil function during the transition period. Multiparous Holstein-Friesian cows in late gestation were randomly allocated to an untreated control group (n = 10) or a treatment group in which each cow received 500 g of zeolite A daily (n = 10) for 14 d prior to the expected calving date (actual duration = 17 ± 3 d prepartum). The cows grazed pasture, and each was supplemented with 2 kg/d of maize silage (dry matter basis), with or without zeolite, until calving. Blood samples for neutrophil isolation and analysis of plasma indicators of mineral status, energy status, liver function, and inflammation were collected pretreatment (covariate; d -19); on d -14 and -7 precalving; on the day of calving (d 0); and on d 1, 4, 7, and 28 postcalving. Neutrophils were isolated and gene expression was analyzed using microfluidic gene expression arrays. Neutrophil respiratory burst was assessed using stimulation with phorbol 12-myristate 13-acetate and flow cytometry. Plasma calcium and phosphorus revealed a treatment by time interaction; cows offered zeolite had greater plasma calcium concentrations at d 0, 1, and 4 postcalving and plasma phosphorus concentrations were lower in zeolite-treated cows during the precalving period until d 1 postcalving compared with control animals. Zeolite treatment downregulated neutrophil gene expression of CXCR4 and S100A8 and tended to lower gene expression for other immune mediators (CXCR1, IFNG, S100A12, and S100A9) compared with the control. Zeolite treatment did not affect neutrophil respiratory burst or expression of the other genes investigated. Plasma concentrations of cytokine IL-6 were reduced with zeolite treatment, which was most evident immediately postcalving (d 0, 1, and 7). Overall, feeding zeolite precalving had few effects on neutrophil gene expression and function; however, the lower gene expression of neutrophil inflammatory mediators may be due to altered availability of dietary minerals prepartum and indicates that zeolite A may control inflammation during the transition period.

G31P, CXCR1/2 inhibitor, with cisplatin inhibits the growth of mice hepatocellular carcinoma and mitigates high‑dose cisplatin-induced nephrotoxicity

Cisplatin (DDP), a cytotoxic antitumor drug, functions in a dose-dependent manner. However, the pursuit for high‑dose therapeutic effects leads to more serious side effects including kidney toxicity. Nephrotoxicity caused due to endothelial cell dysfunction and neutrophils infiltration in kidneys. Interleukin-8 (IL-8) is an ELR+ chemokine binds with CXCR1/2 receptors and its role is primarily in neutrophils recruitment and also involved in invasion, angiogenesis and metastasis of different solid tumors including liver cancer. G31P, a CXCR1/2 antagonist, binds with CXCR1/2 with high affinity, and acts as an anti-inflammatory and antitumor agent. In the present study, we examined the antitumor effects of G31P and DDP on mouse liver cancer cells, and the effects exerted by G31P on cisplatin-induced renal injury. In vitro, effects of the G31P and DDP regimen on H22 cell proliferation were investigated by MTT assay. In vivo BALB/c mice were inoculated subcutaneously with 1x106 H22 cells and treated after one week with a high single dose of DDP with and without G31P on alternative days until the experiment was terminated. On the 15th day the mice were sacrificed, dissected and kidney tissues were analyzed using H&E staining. Myeloperoxidase (MPO) activity was assessed and RT-PCR was performed to detect inflammatory cytokines. Solid tumors were weighed for tumor growth and performed pathological examination, immunohistochemistry and western blotting were performed to detect tissue-related protein expressions in tumor tissue. The tumor inhibitory rate of DDP, G31P and DDP+G31P groups was 38.40, 40.74 and 74.80%, respectively, and the general state of mice in the DDP+G31P group was significantly improved as compared to the DDP group. The results indicated that G31P with DDP significantly inhibited the proliferation while the growth of H22 cell carnimona in vitro and in vivo enhanced the efficacy of cisplatin in cancer treatment with reduced side effects on acute renal failure.

Blockade of CXCR2 signalling: A potential therapeutic target for preventing neutrophil-mediated inflammatory diseases

Polymorphonuclear neutrophils (PMN) play a key role in host innate immune responses by migrating to the sites of inflammation. Furthermore, PMN recruitment also plays a significant role in the pathophysiology of a plethora of inflammatory disorders such as chronic obstructive pulmonary disease (COPD), gram negative sepsis, inflammatory bowel disease (IBD), lung injury, and arthritis. Of note, chemokine-dependent signalling is implicated in the amplification of immune responses by virtue of its role in PMN chemotaxis in most of the inflammatory diseases. It has been clinically established that impediment of PMN recruitment ameliorates disease severity and provides relief in majority of other immune-associated disorders. This review focuses on different novel approaches clinically proven to be effective in blocking chemokine signalling associated with PMN recruitment that includes CXCR2 antagonists, chemokine analogs, anti-CXCR2 monoclonal antibodies, and CXCR2 knock-out models. It also highlights the significance of the utility of nanoparticles in drugs used for blocking migration of PMN to the sites of inflammation.

ELR-CXC chemokine antagonism and cisplatin co-treatment additively reduce H22 hepatoma tumor progression and ameliorate cisplatin-induced nephrotoxicity

Cisplatin (cis-diamminedichloroplatinum) is one of the most commonly used agents for the chemotherapy of various types of cancers, but its use is limited by its dose-dependent side-effects (e.g., nephrotoxicity). The ELR-CXC chemokines are potent tumor growth, metastatic and angiogenic factors and can foster tumor resistance to chemotherapeutic agents. They are also potent proinflammatory agents. The aim of the present study was to evaluate the added effects of combining cisplatin chemotherapy with ELR-CXC chemokine antagonism in a mouse H22 hepatoma cancer cell model. The mice were injected with tumor cells and were then treated with cisplatin (12.5 or 2 mg/kg doses), either alone or together with the chemokine antagonist CXCL8(3-72)K11R/G31P (G31P) (50 µg/kg). At varying time-points renal function was examined using blood urea nitrogen (BUN) and serum creatinine (SCr) as read-outs for the toxic effects of cisplatin, while tumor growth and metastasis were assessed as endpoints. High-dose cisplatin therapy reduced the tumor burden by 52%, while co-delivery of G31P further augmented the tumor growth-suppressive effects of this dose of cisplatin to 71%; G31P by itself and low-dose cisplatin reduced the tumor burden by 19 and 39%, respectively. G31P also reduced the nephrotoxic effects of high-dose cisplatin to the effects observed in the low-dose cisplatin-treated animals. These data confirm the beneficial effects of combined cisplatin chemotherapy and ELR-CXC chemokine anatagonism in the context of both tumor progression and adverse side-effects.

The role of chemokines in B cell chronic lymphocytic leukaemia: pathophysiological aspects and clinical impact

Chemokines are centrally involved in leukocyte migration, homing and haematopoiesis. Besides these physiological aspects, their role in pathological processes especially with respect to solid tumour and haematological neoplasias is well established. In this context, the focus was set here on disclosing their contribution in B cell chronic lymphocytic leukaemia (B-CLL), which is regarded as the most characteristic low-grade lymphoma. Up to now, it has been demonstrated that several chemokines are involved in migration of B-CLL cells to lymph nodes, secondary lymphoid organs and bone marrow. Moreover, some chemokines are known to have an anti-apoptotic effect and thus contribute to the survival of B-CLL cells. By interfering with both of these aspects, new therapeutic targets for this yet incurable disease may be developed. Furthermore, a correlation can be drawn between the concentration of some chemokines in patients' serum, the expression of their respective receptors on B-CLL cells and well-established predictive clinical parameters. Consequently, further systematic investigation of the chemokine network may lead to the identification of new diagnostic and prognostic markers. This review focuses on the impact of chemokines and their receptors on B-CLL pathophysiology and points out potential implications for both treatment and diagnosis.

Blockade of neutrophil responses in aspiration pneumonia via ELR-CXC chemokine antagonism does not predispose to airway bacterial outgrowth

Pneumonia associated with aspiration of bacterial-laden gastric contents is characterized by Glu-Leu-Arg (ELR)-CXC chemokine (e.g., CXC2L1, CXCL8) expression leading to local neutrophil sequestration. This neutrophil response is designed to be protective, but overly aggressive responses can be pathogenic in themselves. Herein we assessed whether blocking neutrophil responses in a guinea pig model of aspiration pneumonia would foster airway bacterial growth. Guinea pigs (n=5) were challenged intranasally with saline, acidified saline or acidified gastric contents (35mg/kg body weight, pH 2.0) and treated subcutaneously with 250mug/kg of the human ELR-CXC chemokine antagonist CXCL8((3-72))K11R/G31P (G31P) or saline. After 20h the animals' airway inflammatory responses and bacterial burdens were assessed. A loss of vascular integrity was apparent in the lungs of the saline-treated aspiration pneumonia animals (12.07+/-1.3% of the pleural surfaces exhibited hemorrhagic consolidation, 4.6x10(6) RBC/ml bronchoalveolar lavage fluid [BALF]), as was a pulmonary neutrophilia. The BAL fluids contained gram-negative and -positive bacteria (total load, 6.3+/-3.2x10(7) CFU/ml BALF) that are associated with nosocomial infections in humans. The G31P-treatments attenuated the pulmonary vascular complications (2.27+/-0.5% pleural surface hemorrhagic consolidation, 0.46x10(6) RBC/ml BALF), and reduced the pulmonary neutrophilia by >/=86%. The G31P-treatments did not lead to significant changes in the airway bacterial loads (total load, 3.46+/-1.8x10(7) CFU/ml BALF). This data indicates that attenuation of the pulmonary neutrophil response in aspiration pneumonia reduces pathology very significantly but does not reduce the efficiency of pulmonary bacterial clearance.

The functional significance behind expressing two IL-8 receptor types on PMN

PMN are critical to innate immunity and are fundamental to antibacterial defense. To localize to sites of infection, PMN possess receptors that detect chemoattractant stimuli elicited at the site, such as chemokines, complement split products, or bioactive lipids. Signaling through these receptors stimulates chemotaxis toward the site of infection but also activates a number of biochemical processes, with the result that PMN kill invading bacteria. PMN possess two receptors, CXCR1 and CXCR2, for the N-terminal ELR motif-containing CXC chemokines, although only two chemokine members bind both receptors and the remainder binding only CXCR2. This peculiar pattern in receptor specificity has drawn considerable interest and investigation into whether signaling through each receptor might impart unique properties on the PMN. Indeed, at first glance, CXCR1 and CXCR2 appear to be functionally redundant; however, there are differences. Considering these proinflammatory activities of activating PMN through chemokine receptors, there has been great interest in the possibility that blocking CXCR1 and CXCR2 on PMN will provide a therapeutic benefit. The literature examining CXCR1 and CXCR2 in PMN function during human and modeled diseases will be reviewed, asking whether the functional differences can be perceived based on alterations in the role PMN play in these processes.