Chemoattractants for neutrophils in lipopolysaccharide-induced inflammatory exudate from rats are not interleukin-8 counterparts but gro-gene-product/melanoma-growth-stimulating-activity-related factors

Differences in the anatomy and physiology of the human and rat respiratory tracts and impact on toxicological assessments

Inhalation is a critical route through which substances can exert adverse effects in humans; therefore, it is important to characterize the potential effects that inhaled substances may have on the human respiratory tract by using fit for purpose, reliable, and human relevant testing tools. In regulatory toxicology testing, rats have primarily been used to assess the effects of inhaled substances as they-being mammals-share similarities in structure and function of the respiratory tract with humans. However, questions about inter-species differences impacting the predictability of human effects have surfaced. Disparities in macroscopic anatomy, microscopic anatomy, or physiology, such as breathing mode (e.g., nose-only versus oronasal breathing), airway structure (e.g., complexity of the nasal turbinates), cell types and location within the respiratory tract, and local metabolism may impact inhalation toxicity testing results. This review shows that these key differences describe uncertainty in the use of rat data to predict human effects and supports an opportunity to harness modern toxicology tools and a detailed understanding of the human respiratory tract to develop testing approaches grounded in human biology. Ultimately, as the regulatory purpose is protecting human health, there is a need for testing approaches based on human biology and mechanisms of toxicity.

Topical, immunomodulatory epoxy-tiglianes induce biofilm disruption and healing in acute and chronic skin wounds

The management of antibiotic-resistant, bacterial biofilm infections in chronic skin wounds is an increasing clinical challenge. Despite advances in diagnosis, many patients do not derive benefit from current anti-infective/antibiotic therapies. Here, we report a novel class of naturally occurring and semisynthetic epoxy-tiglianes, derived from the Queensland blushwood tree ( Fontainea picrosperma) , and demonstrate their antimicrobial activity (modifying bacterial growth and inducing biofilm disruption), with structure/activity relationships established against important human pathogens. In vitro, the lead candidate EBC-1013 stimulated protein kinase C (PKC)–dependent neutrophil reactive oxygen species (ROS) induction and NETosis and increased expression of wound healing–associated cytokines, chemokines, and antimicrobial peptides in keratinocytes and fibroblasts. In vivo, topical EBC-1013 induced rapid resolution of infection with increased matrix remodeling in acute thermal injuries in calves. In chronically infected diabetic mouse wounds, treatment induced cytokine/chemokine production, inflammatory cell recruitment, and complete healing (in six of seven wounds) with ordered keratinocyte differentiation. These results highlight a nonantibiotic approach involving contrasting, orthogonal mechanisms of action combining targeted biofilm disruption and innate immune induction in the treatment of chronic wounds.

CXCR1- or CXCR2-modified CAR T cells co-opt IL-8 for maximal antitumor efficacy in solid tumors

Chimeric antigen receptor (CAR) T-cell therapy targeting solid tumors has stagnated as a result of tumor heterogeneity, immunosuppressive microenvironments, and inadequate intratumoral T cell trafficking and persistence. Early (≤3 days) intratumoral presentation of CAR T cells post-treatment is a superior predictor of survival than peripheral persistence. Therefore, we have co-opted IL-8 release from tumors to enhance intratumoral T-cell trafficking through a CAR design for maximal antitumor activity in solid tumors. Here, we demonstrate that IL-8 receptor, CXCR1 or CXCR2, modified CARs markedly enhance migration and persistence of T cells in the tumor, which induce complete tumor regression and long-lasting immunologic memory in pre-clinical models of aggressive tumors such as glioblastoma, ovarian and pancreatic cancer.

CAR T-cell therapy efficacy in solid tumors is limited by inadequate T-cell migration and/or persistence in tumour microenvironment. Here, the authors show that the activity of tumour-antigen specific CAR T cells, in multiple preclinical mouse models, can be enhanced by co-expression of two IL-8 receptors that mediate their migration into the tumor microenvironment when IL-8 production in tumor is naturally expressed or enhanced by radiation.

Imaging the neutrophil: Intravital microscopy provides a dynamic view of neutrophil functions in host immunity

Neutrophils are the first cellular responders of the immune system. They employ their impressive arsenal of microbicidal molecules to provide rapid and efficient defense against pathogens. However, the role of neutrophils extends far beyond microbial destruction to include tissue repair and remodeling, provision of signals to the adaptive immune system and body homeostasis. Intravital imaging has allowed the visualization of neutrophils in their native environment in both health and disease and provided crucial insights into their mechanisms of action. In the last few years the power of intravital imaging has been considerably extended by the introduction of photoconvertible proteins and intracellular signaling reporter mice. This review will highlight recent advances in our understanding of neutrophil biology based on the use of intravital microscopy to visualize their modus operandi in vivo including migration in and out of inflamed tissues, host-pathogen interactions and cell fate.

Generation and Characterization of Inhibitory Antibodies Specific to Guinea Pig CXCR1 and CXCR2

CXCR1 and CXCR2 are chemokine receptors that have different selectivity of chemokine ligands, but the distinct role of each receptor is not clearly understood. This is due to the absence of specific inhibitors in guinea pigs, which are the appropriate species for investigation of CXCR1 and CXCR2 because of their functional similarity to humans. In this study, we generated and evaluated monoclonal antibodies that specifically bound to guinea pig CXCR1 (gpCXCR1) and guinea pig CXCR2 (gpCXCR2) for acquisition of specific inhibitors. To assess the activity of antibodies, we established CHO-K1 cells stably expressing either gpCXCR1 or gpCXCR2 (CHO/gpCXCR1 or CHO/gpCXCR2). CHO/gpCXCR1 showed migration in response to guinea pig interleukin (IL)-8, and CHO/gpCXCR2 showed migration in response to both guinea pig IL-8 and guinea pig growth-regulated oncogene α. The receptor selectivities of the chemokines of guinea pigs were the same as the human orthologs. The inhibitory activities of the anti-gpCXCR1 and anti-gpCXCR2 monoclonal antibodies on cell migration were observed in a concentration-dependent manner. In conclusion, we successfully obtained inhibitory antibodies specific to gpCXCR1 and gpCXCR2. These inhibitory antibodies will be useful to clarify the physiological roles of CXCR1 and CXCR2 in guinea pigs.

C-reactive protein enhances murine antibody-mediated transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a syndrome of respiratory distress triggered by blood transfusions and is the leading cause of transfusion-related mortality. TRALI has primarily been attributed to passive infusion of HLA and/or human neutrophil antigen antibodies present in transfused blood products, and predisposing factors such as inflammation are known to be important for TRALI initiation. Because the acute-phase protein C-reactive protein (CRP) is highly upregulated during infections and inflammation and can also enhance antibody-mediated responses such as in vitro phagocytosis, respiratory burst, and in vivo thrombocytopenia, we investigated whether CRP affects murine antibody-mediated TRALI induced by the anti-major histocompatibility complex antibody 34-1-2s. We found that BALB/c mice injected with 34-1-2s or CRP alone were resistant to TRALI, however mice injected with 34-1-2s together with CRP had significantly enhanced lung damage and pulmonary edema. Mechanistically, 34-1-2s injection with CRP resulted in a significant synergistic increase in plasma levels of the neutrophil chemoattractant macrophage inflammatory protein-2 (MIP-2) and pulmonary neutrophil accumulation. Importantly, murine MIP-2 is the functional homolog of human interleukin-8, a known risk factor for human TRALI. These results suggest that elevated in vivo CRP levels, like those observed during infections, may significantly predispose recipients to antibody-mediated TRALI reactions and support the notion that modulating CRP levels is an effective therapeutic strategy to reduce TRALI severity.

Xenograft tumors vascularized with murine blood vessels may overestimate the effect of anti-tumor drugs: a pilot study

Recent evidence demonstrated that endothelial cells initiate signaling events that enhance tumor cell survival, proliferation, invasion, and tumor recurrence. Under this new paradigm for cellular crosstalk within the tumor microenvironment, the origin of endothelial cells and tumor cells may have a direct impact on the pathobiology of cancer. The purpose of this pilot study was to evaluate the effect of endothelial cell species (i.e. murine or human) on xenograft tumor growth and response to therapy. Tumor xenografts vascularized either with human or with murine microvascular endothelial cells were engineered, side-by-side, subcutaneously in the dorsum of immunodefficient mice. When tumors reached 200 mm³, mice were treated for 30 days with either 4 mg/kg cisplatin (i.p.) every 5 days or with 40 mg/kg sunitinib (p.o.) daily. Xenograft human tumors vascularized with human endothelial cells grow faster than xenograft tumors vascularized with mouse endothelial cells (P<0.05). Notably, human tumors vascularized with human endothelial cells exhibited nuclear translocation of p65 (indicative of high NF-kB activity), and were more resistant to treatment with cisplatin or sunitinib than the contralateral tumors vascularized with murine endothelial cells (P<0.05). Collectively, these studies suggest that the species of endothelial cells has a direct impact on xenograft tumor growth and response to treatment with the chemotherapeutic drug cisplatin or with the anti-angiogenic drug sunitinib.

Keratinocyte-derived chemokine in obesity: expression, regulation, and role in adipose macrophage infiltration and glucose homeostasis

Obese adipose tissue (AT) is associated with chronic inflammation, and we hypothesized that the keratinocyte-derived chemokine (KC), the mouse ortholog of human interleukin-8, plays a role in obesity-mediated AT inflammation and the subsequent manifestation of insulin resistance. KC expression is increased in the AT and plasma of genetically (ob/ob) and high fat diet-induced obese mouse models, and this increase may be mediated by the elevated leptin and tumor necrosis factor-alpha levels associated with obesity. Obesity-induced KC expression occurs primarily in stromal vascular cells and not in adipocytes, and it is high in preadipocytes and decreases during adipogenesis. Although KC has no effect on adipogenesis, it induces adipocyte expression of inflammatory factors and the insulin resistance mediator, suppressor of cytokine signaling 3. Using chimeric mice deficient in the KC receptor CXCR2 in their bone marrow, we show that the lack of CXCR2 in hematopoietic cells is sufficient to protect from adipose and skeletal muscle macrophage recruitment and development of insulin resistance in diet-induced obese mice. These studies suggest that KC and its receptor CXCR2 are potential targets for the development of new therapeutic approaches for treatment of obesity-related insulin resistance, type II diabetes, and related cardiovascular diseases.

The peptide analogue of MCP-1 65-76 sequence is an inhibitor of inflammation

Inflammation plays an important role in vessel wall remodeling that occurs in atherosclerosis and postangioplasty restenosis. Monocytic chemoattractant protein-1 (MCP-1) is one of the main attractors of monocytes and some lymphocyte subsets to the damaged vessel. The aims of the study were to confirm MCP-1 participation in the development of acute coronary syndromes, to produce the potential MCP-1 peptide antagonist, and to investigate its effects in vitro and in vivo in different animal models of inflammation. MCP-1 plasma concentration was measured by ELISA (enzyme-linked immunosorbent assay). Chemokine receptor expression by cells isolated from human atherosclerotic lesions was assessed by direct immunofluorescence and flow cytometry. MCP-1 sequence was analyzed with Peptide Companion software and peptides were synthesized using Fmoc strategy. The peptide resistance to degradation was checked by 1H-NMR spectroscopy. The peptide effect on MCP-1-stimulated cell migration was studied in Boyden chamber and in mouse air pouch model, and its influence on lipopolysaccharide (LPS)-induced inflammatory cell recruitment was investigated in models of subcutaneous inflammation in rats and nonhuman primates. We revealed nearly a 2-fold increase of MCP-1 plasma level in patients with unstable angina in comparison with patients with stable angina. The atherosclerotic plaque specimens obtained from patients with unstable angina contained a significant amount of chemokine receptor-expressing leukocytes. Peptide from MCP-1 C-terminal 65-76 sequence (peptide X) inhibited MCP-1-stimulated monocytic cell migration in vitro and in vivo. Peptide X labeled with 99mTc accumulated specifically at sites of inflammation in rats. Peptide X administrated i.m and i.v. suppressed monocyte and granulocyte recruitment induced by subcutaneous injection of LPS in the back of rats and non-human primates. Our data demonstrate that MCP-1-mediated chemotaxis could be responsible for atherosclerotic plaque "destabilization". Peptide X may represent a new class of anti-inflammatory drugs to be used in cardiology.

c-Src Mediates Thrombin-Induced NF-κB Activation and IL-8/CXCL8 Expression in Lung Epithelial Cells

In this study, we examined the regulation of NF-kappaB activation and IL-8/CXCL8 expression by thrombin in human lung epithelial cells (EC). Thrombin caused a concentration-dependent increase in IL-8/CXCL8 release in a human lung EC line (A549) and primary normal human bronchial EC. In A549 cells, thrombin, SFLLRN-NH2 (a protease-activated receptor 1 (PAR1) agonist peptide), and GYPGQV-NH2 (a PAR4 agonist peptide), but not TFRGAP-NH2 (a PAR3 agonist peptide), induced an increase in IL-8/CXCL8-luciferase (Luc) activity. The thrombin-induced IL-8/CXCL8 release was attenuated by D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (a thrombin inhibitor), U73122 (a phosphoinositide-phospholipase C inhibitor), Ro-32-0432 (a protein kinsase C alpha (PKC alpha) inhibitor), an NF-kappaB inhibitor peptide, and Bay 117082 (an IkappaB phosphorylation inhibitor). Thrombin-induced increase in IL-8/CXCL8-Luc activity was inhibited by the dominant-negative mutant of c-Src and the cells transfected with the kappaB site mutation of the IL-8/CXCL8 construct. Thrombin caused time-dependent increases in phosphorylation of c-Src at tyrosine 416 and c-Src activity. Thrombin-elicited c-Src activity was inhibited by Ro-32-0432. Stimulation of cells with thrombin activated IkappaB kinase alphabeta (IKK alphabeta), IkappaB alpha phosphorylation, IkappaB alpha degradation, p50 and p65 translocation from the cytosol to the nucleus, NF-kappaB-specific DNA-protein complex formation, and kappaB-Luc activity. Pretreatment of A549 cells with Ro-32-4032 and the dominant-negative mutant of c-Src DN inhibited thrombin-induced IKK alphabeta activity, kappaB-Luc activity, and NF-kappaB-specific DNA-protein complex formation. Further studies revealed that thrombin induced PKC alpha, c-Src, and IKK alphabeta complex formation. These results show for the first time that thrombin, acting through PAR1 and PAR4, activates the phosphoinositide-phospholipase C/PKC alpha/c-Src/IKK alphabeta signaling pathway to induce NF-kappaB activation, which in turn induces IL-8/CXCL8 expression and release in human lung EC.

Tumour-associated macrophages and melanoma tumourigenesis: integrating the complexity

When the body discovers a tumour cell (foreign antigen), several kinds of mechanisms and cells operate in what is called an immune response. The latter has evolved into two mechanisms: non-specific immunity and specific immunity, which are closely linked to and influence each other. The former represents the first line of defence against neoplastic cells. The adaptive (specific) immunity is orchestrated by antigen-specific T and B lymphocytes. The effector cells of innate immunity include granulocytes, macrophages and natural killer cells. Among these cells, macrophages represent the most important part of innate immunity against tumours. Tumour-associated macrophages (TAMs) are important antigen-presenting cells and as such an understanding of their interactions with tumour cells gives insights into novel therapeutic strategies. In tumours, the effect of TAMs is the outcome of their two concomitantly competing interactions: tumour growth reduction and tumour growth promotion. The macrophage (TAMs) content of melanoma ranges from 0 to 30% and their density increases with increasing tumour thickness. The melanoma cells and TAMs seem to interact with each other through the release of soluble factors that either prevent or enhance tumour growth. For instance, syngeneic macrophages from tumour-bearing mice can inhibit melanoma growth in the nude mice more than the control macrophages. Alternatively, metastatic B16 melanoma cells can produce some macrophage cytotoxic substances that help tumour cells not only escape the host immunosurveillance system but also prevent distant metastasis. Together, these observations suggest opposing effects for these soluble factors in melanoma. To date, little is available in the literature about the interactions between TAMs and melanoma cells. This viewpoint not only tries to examine these interactions but also provides relevant speculations.

Role of pancreatic trypsin in chronic esophagitis induced by gastroduodenal reflux in rats

BACKGROUND

Reflux of the duodenal contents with gastric acid has been reported to contribute to the development of esophageal mucosal damage and inflammation. Recent studies show that pancreatic trypsin can stimulate the production of inflammatory mediators, including chemokines and prostaglandins from human esophageal epithelial cells in vitro. The aim of the present study was to investigate the role of pancreatic trypsin in the pathogenesis of chronic esophageal inflammation induced by gastroduodenal reflux in rats.

METHODS

Esophagogastroduodenal anastomosis was carried out in male Wistar rats by anastomosing the jejunum to the gastroesophageal junction under diethyl ether inhalation anesthesia. The animals undergoing surgery were treated with the control diet, rabeprazole sodium, nizatidine, ecabet sodium, camostat mesilate (CMM), ONO-1714, a specific inducible nitric oxide synthase (iNOS) inhibitor, or meloxicam, a selective cyclooxygenase-2 (COX-2) inhibitor. Esophageal injury was evaluated by macroscopic and microscopic findings, and mRNA expression for CINC-1, COX-2, and iNOS was determined by real-time polymerase chain reaction (PCR). Trypsin activity within the esophageal lumen was measured 2 weeks after surgery, and the expression of protease-activated receptor (PAR)-1 and -2 was confirmed by reverse transcription (RT)-PCR.

RESULTS

At 8 weeks after surgery, gastroduodenal reflux induced esophageal erosions and ulcer formation as well as marked thickening of the esophageal wall. Histological study showed an increase of thickness of the esophageal mucosa, hyperplasia of the epidermis and basal cells, ulcer formation, and marked infiltration of inflammatory cells. The macroscopic ulcer score and histological ulcer length were significantly reduced by treatment with rabeprazole or CMM but not by nizatidine or ecabet sodium, compared with each control. Rabeprazole, nizatidine, or ecabet sodium did not affect the severity of mucosal hyperplastic scores or histological parameters in esophagitis. In contrast, the CMM group showed a significant decrease in the mucosal hyperplastic and inflammatory scores. The enhanced expression of CINC-1, COX-2, and iNOS mRNA in the control group was also markedly inhibited in the CMM-treated group. ONO-1714 or meloxicam treatment significantly reduced the macroscopic scores of ulcer and hyperplasia. The trypsin activity in the esophageal lumen was significantly increased in the control diet group, and this increase was significantly inhibited in the CMM-treated group. The expression of PAR-1 and -2 mRNA was confirmed in rat esophageal epithelium.

CONCLUSIONS

With this model, we have demonstrated that CMM significantly reduces inflammation and hyperplasia in the esophageal mucosa. These results indicate that trypsin, which is primarily inhibited by CMM, plays an important role in the mucosal damage induced by gastroduodenal reflux and that it can be a therapeutic target in patients with gastroduodenal reflux esophagitis.

Inhibition of endotoxin- and antigen-induced airway inflammation by fudosteine, a mucoactive agent

We evaluated the effect of a mucoactive agent (-)-(R)-2-amino-3-(3-hydroxypropylthio) propionic acid (fudosteine), on airway inflammation using endotoxin- and antigen-induced models. Time courses of growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) production, neutrophil migration and goblet cell hyperplasia were examined in endotoxin-induced rat airway inflammation. GRO/CINC-1 in bronchoalveolar lavage fluid (BALF) increased in response to intratracheal instillation of endotoxin and peaked within 4 h. Neutrophils in BALF and goblet cells on trachea peaked 24 and 96 h after endotoxin instillation, respectively. Fudosteine significantly inhibited increases in GRO/CINC-1 at 10-100 mg/kg, and neutrophils and goblet cells at 30 and 100 mg/kg. These results suggest that inflammatory events including neutrophil chemoattractant production and neutrophil migration play important roles for goblet cell hyperplasia in endotoxin-induced airway inflammation, and fudosteine inhibits goblet cell hyperplasia by inhibiting GRO/CINC-1 production and/or neutrophil migration. Furthermore, fudosteine (100 mg/kg) inhibited ovalbumin-induced eosinophil infiltration into BALF, suggesting it attenuates asthmatic inflammation.

IL-8 is a key chemokine regulating neutrophil recruitment in a new mouse model of Shigella-induced colitis

The lack of a mouse model of acute rectocolitis mimicking human bacillary dysentery in the presence of invasive Shigella is a major handicap to study the pathogenesis of the disease and to develop a Shigella vaccine. The inability of the mouse intestinal mucosa to elicit an inflammatory infiltrate composed primarily of polymorphonuclear leukocytes (PMN) may be due to a defect in epithelial invasion, in the sensing of invading bacteria, or in the effector mechanisms that recruit the PMN infiltrate. We demonstrate that the BALB/cJ mouse colonic epithelium not only can be invaded by Shigella, but also elicits an inflammatory infiltrate that, however, lacks PMN. This observation points to a major defect of mice in effector mechanisms, particularly the lack of expression of the CXC chemokine, IL-8. Indeed, this work demonstrates that the delivery of recombinant human IL-8, together with Shigella infection of the colonic epithelial surface, causes an acute colitis characterized by a strong PMN infiltrate that, by all criteria, including transcription profiles of key mediators of the innate/inflammatory response and histopathological lesions, mimics bacillary dysentery. This is a major step forward in the development of a murine model of bacillary dysentery.

Analysis of the mechanism regulating the stability of rat macrophage inflammatory protein-2 mRNA in RBL-2H3 cells

Using rat peritoneal neutrophils, the complete nucleotide sequence of rat macrophage inflammatory protein-2 (MIP-2) mRNA including 5'untranslated region (UTR) and 3'UTR was determined (GenBank Accession number, AB060092). It was found that the MIP-2 mRNA has a 70 bp 5'UTR, a 303 bp coding region and a 728 bp 3'UTR which contains adenylate/uridylate (AU)-rich areas defined as AU-rich elements (AREs). Site-directed mutagenesis studies using the tetracycline-sensitive transactivator protein-expressing rat basophilic leukemia cells (RBL-2H3-TO cells) revealed that MIP-2 mRNA mutants which lack the 3'UTR are more stable than MIP-2-wild-type (wt) mRNA. A MIP-2 mRNA mutant in which some mutations were introduced to the ARE was also stable. The stability of MIP-2 mRNA was low in untreated RBL-2H3-TO cells, but it increased in the antigen-stimulated immunoglobulin E (IgE)-sensitized cells. The antigen-induced MIP-2 mRNA stabilization was counteracted by the highly specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 and the MAPK/ERK kinase (MEK-1) inhibitor PD98059. These findings indicate that ARE is the cis-element which mediates the rapid decay of MIP-2 mRNA, and the antigen stimulation stabilizes MIP-2 mRNA and the p38 MAPK and p44/42 MAPK pathways are involved in the antigen-induced stabilization of MIP-2 mRNA.

Selective transport of cytokine-induced neutrophil chemoattractant from the lung to the blood facilitates pulmonary neutrophil recruitment

The CXC chemokines cytokine-induced neutrophil chemoattractant (CINC) and macrophage inflammatory protein-2 (MIP-2) are potent neutrophil chemoattractants in rats. We have previously shown that CINC, unlike MIP-2 and most other proinflammatory cytokines, is elevated in the systemic circulation in response to an intratracheal (IT) challenge. Therefore, we hypothesized that CINC generated within the lung selectively enters the vascular compartment to facilitate pulmonary neutrophil recruitment. Rats were administered IT LPS, and plasma CINC and MIP-2 levels were measured 90 min and 4 h after injection, along with mRNA expression in lung, spleen, liver, and kidney. Ninety minutes and 4 h after IT LPS, CINC and MIP-2 mRNA expression were largely confined to lung homogenate, but of the two chemokines, only CINC was present in plasma. In separate experiments, rats received IT injections of recombinant CINC and/or MIP-2. Here, plasma levels of CINC, but not MIP-2, were significantly increased throughout the 4-h observation period. This finding was verified by individually administering125I-labeled forms of each chemokine. Instillation of recombinant MIP-2 or CINC into the lung increased the number of neutrophils recovered in bronchoalveolar lavage fluid at 4 h, and this effect was enhanced when both chemokines were administered together. In addition, intravenous (IV) CINC, but not IV MIP-2, increased pulmonary neutrophil recruitment in response to IT MIP-2. Our results show that CINC, in contrast to MIP-2, is selectively transported from the lung to the systemic circulation, where it promotes neutrophil migration into the lung in response to a chemotactic stimulus.

Change in location of cytokine-induced neutrophil chemoattractants (CINCs) in pulmonary silicosis

Rat cytokine-induced neutrophil chemoattractants (CINCs), which belong to the interleukin-8 family, are known to be induced by treatment with lipopolysaccharide (LPS). Recently, CINCs were grouped into four subtypes-CINC-1, CINC-2alpha, CINC-2beta, and CINC-3-and CINC-1 was considered to be a major isoform among the four CINCs in LPS-induced acute lung inflammation in rats. The purpose of this study was to investigate the change in location of CINCs with chronic inflammation induced by experimental pulmonary silicosis. Administration of silica particles induced lung granulomas. Immunohistochemical staining for CINCs showed that the number of cells positive for CINC-2alpha, CINC-2beta, and CINC-3 was increased, peaking at 1 day after treatment with silica particles, whereas CINC-1 was almost undetectable. We suggest that CINC-2alpha, CINC-2beta, and CINC-3 are the most important chemoattractants in the formation of granulomas in chronic inflammation.

Effect of endogenous nitric oxide on hyperoxia and tumor necrosis factor-alpha-induced leukosequestration and proinflammatory cytokine release in rat airways

OBJECTIVE

To investigate the effects of endogenous nitric oxide on hyperoxia and tumor necrosis factor-alpha-induced leukosequestration and proinflammatory cytokine release in rat airways.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

Experimental laboratory.

SUBJECTS

Male Sprague-Dawley rats weighing 350-500 g.

INTERVENTIONS

The rats were pretreated with N(G)-nitro-L-arginine methyl ester (L-NAME; 10 mg/kg) or saline intravenously 4-6 mins before intratracheal administration of tumor necrosis factor-alpha, 95% oxygen, or both, when the vasopressor effect of L-NAME had reached a plateau.

MEASUREMENTS AND MAIN RESULTS

Bronchoalveolar lavage fluid was recovered from the airway of rats after exposure to 95% oxygen and tumor necrosis factor-alpha for 6 hrs under ventilator support. Neutrophils in lavage fluid were isolated and examined for the inducible nitric oxide synthase expression by flow-cytometric assay. Tumor necrosis factor-alpha and interleukin-1 beta in lavage fluid were measured by enzyme-linked immunosorbent assay. The percentage of neutrophils in bronchoalveolar fluid was significantly higher in rats exposed to hyperoxia + tumor necrosis factor-alpha (29.7 +/- 12.5%) compared with rats with hyperoxia (16.3 +/- 1.2%), tumor necrosis factor-alpha (4.2 +/- 1.1%), or room air (5.0 +/- 1.8%) alone (p <.05). Rats exposed to hyperoxia + tumor necrosis factor-alpha had significantly higher concentrations of inducible nitric oxide synthase of neutrophils (350.1 +/- 75.7 mean fluorescence intensity), compared with rats with hyperoxia (64.9 +/- 1.6 mean fluorescence intensity), tumor necrosis factor-alpha (102.6 +/- 15.3 mean fluorescence intensity), or room air (111.2 +/- 25.8 mean fluorescence intensity) alone (p <.05). Rats exposed to hyperoxia + tumor necrosis factor-alpha significantly produced higher concentrations of tumor necrosis factor-alpha and interleukin-1 beta, compared with rats with tumor necrosis factor-alpha, hyperoxia, or room air alone. Hyperoxia + tumor necrosis factor-alpha also significantly increased growth-related oncogene/cytokine-induced neutrophil chemoattractant (GRO/CINC)-1 in bronchoalveolar fluid, compared with those receiving tumor necrosis factor-alpha alone, hyperoxia alone, or room air alone. L-NAME significantly enhanced the percentage of neutrophil recovery and the production of tumor necrosis factor-alpha, interleukin-1 beta, and GRO/CINC-1 in airways compared with the corresponding hyperoxia + tumor necrosis factor-alpha treatment alone.

CONCLUSIONS

Endogenous nitric oxide may be an important endogenous inhibitor of hyperoxia + tumor necrosis factor-alpha-induced leukocyte recruitment and subsequently tumor necrosis factor-alpha, interleukin-1 beta, and GRO/CINC-1 release.

Differential effects of ebselen on neutrophil recruitment, chemokine, and inflammatory mediator expression in a rat model of lipopolysaccharide-induced pulmonary inflammation

We postulated that the seleno-organic compound ebselen would attenuate neutrophil recruitment and activation after aerosolized challenge with endotoxin (LPS) through its effect as an antioxidant and inhibitor of gene activation. Rats were given ebselen (1-100 mg/kg i.p.) followed by aerosolized LPS exposure (0.3 mg/ml for 30 min). Airway inflammatory indices were measured 4 h postchallenge. Bronchoalveolar lavage (BAL) fluid cellularity and myeloperoxidase activity were used as a measure of neutrophil recruitment and activation. RT-PCR analysis was performed in lung tissue to assess gene expression of TNF-alpha, cytokine-induced neutrophil chemoattractant-1 (CINC-1), macrophage-inflammatory protein-2 (MIP-2), ICAM-1, IL-10, and inducible NO synthase. Protein levels in lung and BAL were also determined by ELISA. Ebselen pretreatment inhibited neutrophil influx and activation as assessed by BAL fluid cellularity and myeloperoxidase activity in cell-free BAL and BAL cell homogenates. This protective effect was accompanied by a significant reduction in lung and BAL fluid TNF-alpha and IL-1 beta protein and/or mRNA levels. Ebselen pretreatment also prevented lung ICAM-1 mRNA up-regulation in response to airway challenge with LPS. This was not a global effect of ebselen on LPS-induced gene expression, because the rise in lung and BAL CINC-1 and MIP-2 protein levels were unaffected as were lung mRNA expressions for CINC-1, MIP-2, IL-10, and inducible NO synthase. These data suggest that the anti-inflammatory properties of ebselen are achieved through an inhibition of lung ICAM-1 expression possibly through an inhibition of TNF-alpha and IL-1 beta, which are potent neutrophil recruiting mediators and effective inducers of ICAM-1 expression.

Reduced activation of inflammatory responses in host cells by mouse-adapted Helicobacter pylory isolates

Helicobacter pylori strains that harbour the Cag pathogenicity island (Cag PAI) induce interleukin (IL)-8 secretion in gastric epithelial cells, via the activation of NF- kappa B, and are associated with severe inflammation in humans. To investigate the influence of Cag PAI-mediated inflammatory responses on H. pylori adaptation to mice, a selection of H. pylori clinical isolates (n = 12) was cag PAI genotyped and tested in co-culture assays with AGS gastric epithelial cells, and in mouse colonization studies. Six isolates were shown to harbour a complete cag PAI and to induce NF- kappa B activation and IL-8 secretion in AGS cells. Of the eight isolates that spontaneously colonized mice, six had a cag PAI(-) genotype and did not induce pro-inflammatory responses in these cells. Mouse-to-mouse passage of the two cag PAI(+) -colonizing strains yielded host-adapted variants that infected mice with bacterial loads 100-fold higher than those of the respective parental strains (P= 0.001). These mouse-adapted variants were affected in their capacity to induce pro-inflammatory responses in host cells, yet no changes in cag PAI gene content were detected between the strains by DNA microarray analysis. This work provides evidence for in vivo selection of H. pylori bacteria with a reduced capacity to induce inflammatory responses and suggests that such bacteria are better adapted to colonize mice.

Compartmentalization of macrophage inflammatory protein-2, but not cytokine-induced neutrophil chemoattractant, in rats challenged with intratracheal endotoxin

An important feature of the pulmonary inflammatory response is that the production of certain cytokines and chemokines is largely confined to the lung. This study investigated the local and systemic responses of macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) in rats administered with either intratracheal or intravenous lipopolysaccharide (LPS). Intratracheal LPS induced a significant increase in MIP-2 in bronchoalveolar lavage (BAL) fluid with no detectable MIP-2 in the plasma. In contrast, CINC was significantly increased in both BAL fluid and the plasma after intratracheal LPS challenge. Cell-associated MIP-2 was increased in the pulmonary-recruited neutrophils (PMNs) but not in the circulating PMNs in rats given intratracheal LPS. Cell-associated CINC was increased in both the recruited and circulating PMNs in these animals. Intravenous LPS caused a marked increase in plasma MIP-2 and CINC, whereas only a small elevation of both MIP-2 and CINC concentrations in BAL fluid was observed. The lack of CINC compartmentalization compared to MIP-2 implies that these C-X-C chemokines are regulated differentially and may have different effects upon polymorphonuclear leukocyte (PMN) recruitment into the alveolar space in response to intrapulmonary LPS or bacterial challenge.

An inhibitory effect of cytokine-induced neutrophil chemoattractant on corticotropin-releasing factor-induced increase in locomotor activity

To investigate whether cytokine-induced neutrophil chemoattractant (CINC) has an influence on corticotropin-releasing factor (CRF) in the central nervous system, the effects of intracerebroventricular (i.c.v.) injection of CINC on CRF-induced behavior were examined. Intracerebroventricular CRF injection produced an increase in locomotor activity, which was significantly reduced by i.c.v. injection of CINC. The intravenous injection of CINC did not alter CRF-induced locomotor hyperactivity. These results suggested that CINC has a functional antagonistic action on the response to CRF and may attenuate stress responses.

Role of nuclear factor-kappaB in gastric ulcer healing in rats

We investigated the role of nuclear factor-kappaB (NF-kappaB) in gastric ulcer healing in rats. NF-kappaB was activated in ulcerated tissue but not in normal mucosa, and the level of the activation was decreased with ulcer healing. NF-kappaB activation was observed in fibroblasts, monocytes/macrophages, and neutrophils. Treatment of gastric fibroblasts, isolated from the ulcer base, with interleukin-1beta activated NF-kappaB and the subsequently induced cyclooxygenase-2 and cytokine-induced neutrophil chemoattractant-1 (CINC-1) mRNA expression. Inhibition of activated NF-kappaB action resulted in suppression of both their mRNA expression and increases in PGE(2) and CINC-1 levels induced by interleukin-1beta. Persistent prevention of NF-kappaB activation caused an impairment of ulcer healing in rats. Gene expression of interleukin-1beta, CINC-1, cyclooxygenase-2, and inducible nitric oxide synthase in ulcerated tissue had been inhibited before the delay in ulcer healing became manifest. The increased levels of cyclooxygenase-2 protein and PGE(2) production were also reduced. These results demonstrate that NF-kappaB, activated in ulcerated tissue, might upregulate the expression of healing-promoting factors responsible for gastric ulcer healing in rats.

Exacerbation of Acanthamoeba keratitis in animals treated with anti-macrophage inflammatory protein 2 or antineutrophil antibodies

Neutrophils are thought to be involved in many infectious diseases and have been found in high numbers in the corneas of patients with Acanthamoeba keratitis. Using a Chinese hamster model of keratitis, conjunctival neutrophil migration was manipulated to determine the importance of neutrophils in this disease. Inhibition of neutrophil recruitment was achieved by subconjunctival injection with an antibody against macrophage inflammatory protein 2 (MIP-2), a powerful chemotactic factor for neutrophils which is secreted by the cornea. In other experiments, neutrophils were depleted by intraperitoneal injection of anti-Chinese hamster neutrophil antibody. The inhibition of neutrophils to the cornea resulted in an earlier onset and more severe infection compared to controls. Anti-MIP-2 antibody treatment produced an almost 35% reduction of myeloperoxidase activity in the cornea 6 days postinfection, while levels of endogenous MIP-2 secretion increased significantly. Recruitment of neutrophils into the cornea via intrastromal injections of recombinant MIP-2 generated an initially intense inflammation that resulted in the rapid resolution of the corneal infection. The profound exacerbation of Acanthamoeba keratitis seen when neutrophil migration was inhibited, combined with the rapid clearing of the disease in the presence of increased neutrophils, strongly suggests that neutrophils play an important role in combating Acanthamoeba infections in the cornea.

Role of cytokine-induced neutrophil chemoattractant-2 (CINC-2) alpha in a rat model of chronic bronchopulmonary infections with Pseudomonas aeruginosa

In order to investigate the role of the cytokine-induced neutrophil chemoattractant (CINC) in chronic bronchopulmonary infection, we developed a rat model of bronchopulmonary infection with Pseudomonas aeruginosa by using the agar bead method, and determined the kinetics of bacterial and cell number, as well as the concentrations of CINC-1, CINC-2, and CINC-3 in bronchoalveolar lavage (BAL) fluids in this model. The bacterial number in the lung rapidly increased from days 1 to 4, and declined 14 days after challenge. Neutrophil number in BAL fluid increased up to one day after challenge, and then slowly decreased during 14 days post-challenge. Among the CINCs, the local production of CINC-2 alpha sharply increased at day 1 and then decreased until day 4 post-challenge, while the local production of CINC-1 slightly increased at day 1 post-challenge. Neither CINC-2 beta nor CINC-3 were detected during the entire course of the infection. Increased CINC-2 mRNA expression in the lung tissue after challenge was associated with CINC-2 alpha production in BAL fluid. Moreover, an immunohistochemical study demonstrated the localization of CINC-1 and CINC-2 alpha primarily in alveolar macrophages and, to a much lesser extent, in bronchial epithelium of infected lung tissues, whereas CINC-2 beta and CINC-3 were not detected. When anti-CINC-1 or anti-CINC-2 alpha polyclonal antibodies were used for neutralizing neutrophil chemotactic activities in BAL fluids, the anti-CINC-2 alpha antibody inhibited 70% of the chemotactic activity in BAL fluids from infected rats at day 1 after challenge. No inhibition was observed by anti-CINC-1 antibody. These data indicate that CINC-2 alpha, which is produced by alveolar macrophages and bronchial epithelial cells, plays a pivotal role in neutrophil accumulation in the airway of a rat model of chronic bronchopulmonary infection with P. aeruginosa.

Role of cyclooxygenase-2 in Helicobacter pylori- induced gastritis in Mongolian gerbils

Cyclooxygenase (COX)-2 expression is induced in the gastric mucosa of Helicobacter pylori-infected patients, but its role remains unclear. We examined the effects of NS-398 and indomethacin on gastric pathology in H. pylori-infected Mongolian gerbils. COX-1 was detected in both normal and H. pylori-infected mucosa, whereas COX-2 was expressed only in the infected mucosa. PGE(2) production was elevated by H. pylori infection, and the increased production was reduced by NS-398, which did not affect PGE(2) production in normal mucosa. Indomethacin inhibited PGE(2) production in both normal and infected mucosa. Hemorrhagic erosions, neutrophil infiltration, lymphoid follicles, and epithelium damage were induced by H. pylori infection. NS-398 and indomethacin aggravated these pathological changes but did not increase viable H. pylori number. H. pylori-increased production of neutrophil chemokine and interferon-gamma was potentiated by NS-398 and indomethacin. Neither NS-398 nor indomethacin caused any pathological changes or cytokine production in normal animals. These results indicate that COX-2 as well as COX-1 might play anti-inflammatory roles in H. pylori-induced gastritis.

Chemokines are produced in the brain early during the course of experimental African trypanosomiasis

African trypanosomiasis is characterized by progressive central nervous system (CNS) involvement. Using single and double immunohistochemistry, we evaluated the induction of alpha- and beta-chemokines in brains of Sprague-Dawley rats infected with Trypanosoma brucei brucei (T. b. brucei) and identified their cellular source. The results showed high production of MIP-2, RANTES and MIP-1alpha and to a lower extend MCP-1 in infected animals compared to controls. MIP-2, RANTES and MIP-1alpha were produced early by astrocytes and microglia and later by macrophages and T-cells. These findings suggest that chemokines may contribute to the immunopathogenesis that occurs in the CNS early during infections.

Chemokines are upregulated during orthodontic tooth movement

In the early stage of orthodontic tooth movement, an acute inflammatory response characterized by the migration of leukocytes occurs. This response suggests the presence of specific chemotactic signals that may play a role in the mechanism of bone remodeling, in particular in resorption. The aim of the present study was to explore the induction of potential chemokines at the resorption side during orthodontic tooth movement. Monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and macrophage inflammatory protein-2 (MIP-2) were examined by in situ hybridization using radioactive synthetic oligoneucleotide probes. Mesial movement of the upper first molars was performed with a fixed appliance for 3, 7, and 10 days. The results demonstrated that MCP-1, RANTES, and MIP-2 were highly expressed during orthodontic movement. On day 3, MCP-1 showed maximum induction in the pressure zone, followed in intensity by RANTES and MIP-2, although not in the contralateral control side. The induction of these chemokines had declined on day 7 and reached low levels on day 10. Our data suggest that chemokines are induced early in the application of force, and such induction may contribute to the early inflammatory response that may be responsible in part for the ensuing bone remodeling.

Chemokine responses and accumulation of inflammatory cells in the lungs of mice infected with highly virulent Cryptococcus neoformans: effects of interleukin-12

We examined the mechanisms involved in the development of lung lesions after infection with Cryptococcus neoformans by comparing the histopathological findings and chemokine responses in the lungs of mice infected with C. neoformans and assessed the effect of interleukin (IL) 12 which protects mice from lethal infection. In mice infected intratracheally with a highly virulent strain of C. neoformans, the yeast cells multiplied quickly in the alveolar spaces but only a poor cellular inflammatory response was observed throughout the course of infection. Very little or no production of chemokines, including MCP-1, RANTES, MIP-1alpha, MIP-1beta and IP-10, was detected at the mRNA level using RT-PCR as well as at a protein level in MCP-1, RANTES and MIP-1alpha. In contrast, intraperitoneal administration of IL-12 induced the synthesis of these chemokines and a marked cellular inflammatory response involving histiocytes and lymphocytes in infected mice. Our findings were confirmed by flow cytometry of intraparenchymal leukocytes obtained from lung homogenates which showed IL-12-induced accumulation of inflammatory cells consisting mostly of macrophages and CD4+ alphabeta T cells. On the other hand, C-X-C chemokines including MIP-2 and KC, which attract neutrophils, were produced in infected and PBS-treated mice but treatment with IL-12 showed a marginal effect on their level, and neutrophil accumulation was similar in PBS- and IL-12-treated mice infected with C. neoforman. Our results demonstrate a close correlation between chemokine levels and development of lung lesions, and suggest that the induction of chemokine synthesis may be one of the mechanisms of IL-12-induced protection against cryptococcal infection.

Insulin-induced hypoglycemia activates a chemokinergic neuronal pathway in the hypothalamo-pituitary system

Recently, we found the presence of cytokine-induced neutrophil chemoattractant (CINC) neuronal pathway in the hypothalamo-pituitary system. This observation prompted us to investigate the effect of insulin-induced hypoglycemia on CINC neuronal pathway in the hypothalamo-pituitary system. An insulin injection decreased the plasma glucose level, which followed a prompt rise in plasma ACTH level and an increase in serum CINC level. Before the insulin injection, the signal for CINCmRNA was undetectable in the paraventricular hypothalamic nucleus (PVN). The hypoglycemic challenge induced strong hybridization signals of CINC mRNA in the parvocellular and magnocellular subdivision of the PVN within 30 min, and reached the peak within 3 h. No change was observed in the supraoptic nucleus after the hypoglycemic challenge. These studies demonstrate the presence of a hypoglycemia-sensitive chemokinergic neuronal pathway in the hypothalamo-neurohypophysial system and this newly described pathway will provide novel information for understanding pathophysiology of hypoglycemia.

Upregulation of T-helper 1 cytokines and chemokine expression in post-transplant airway obliteration

The major obstacle to long-term survival after lung transplantation is chronic graft dysfunction manifest as bronchiolitis obliterans. Since the early stages are characterized by proliferation of itinerant cells (lymphocytes and macrophages), we hypothesized that cytokines and chemokines may play a role in the development of the fibroproliferative process. In a heterotopic rat tracheal transplant model, we studied isografts and allografts 3, 7, and 21 d after transplantation as representative time points for the triphasic time course in the evolution of allograft airway obliteration. Using a semiquantitative RT-PCR technique, intragraft gene expression of T-helper 1 (Th1)- and Th2-type cytokines and of C-C and C-X-C chemokines was examined. The results of our study show a distinct pattern of cytokine and chemokine gene expression in the development of post-transplant airway obliteration. Allografts, in contrast to isografts, showed a strong and persistent Th1-type response (expression of interleukin-2 and interferon-gamma genes), even after fibrous airway obliteration was complete, suggesting an ongoing allo-immune process until late in the fibroproliferative stage. RANTES and MCP-1 were also upregulated late after transplantation, whereas MIP-2 upregulation occurred early post-transplant and was not restricted to allografts alone, which might reflect alloantigen-independent processes after transplantation that are present in both allografts and isografts.

Neutralization of macrophage inflammatory protein 2 (MIP-2) and MIP-1alpha attenuates neutrophil recruitment in the central nervous system during experimental bacterial meningitis

Chemokines are low-molecular-weight chemotactic cytokines that have been shown to play a central role in the perivascular transmigration and accumulation of specific subsets of leukocytes at sites of tissue damage. Using in situ hybridization (ISH), we investigated the mRNA induction of macrophage inflammatory protein 2 (MIP-2), MIP-1alpha, monocyte chemoattractant protein 1 (MCP-1), and RANTES. Challenge of infant rats' brains with Haemophilus influenzae type b intraperitoneally resulted in the time-dependent expression of MIP-2, MIP-1alpha, MCP-1, and RANTES, which was maximal 24 to 48 h postinoculation. Immunohistochemistry showed significant increases in neutrophils and macrophages infiltrating the meninges, the ventricular system, and the periventricular area. The kinetics of MIP-2, MIP-1alpha, MCP-1, and RANTES mRNA expression paralleled those of the recruitment of inflammatory cells and disease severity. Administration of anti-MIP-2 or anti-MIP-1alpha antibodies (Abs) resulted in significant reduction of neutrophils. Administration of anti-MCP-1 Abs significantly decreased macrophage infiltration. Combined studies of ISH and immunohistochemistry showed that MIP-2- and MIP-1alpha-positive cells were neutrophils and macrophages. MCP-1-positive cells were neutrophils, macrophages, and astrocytes. Expression of RANTES was localized predominantly to resident astrocytes and microglia. The present study indicates that blocking of MIP-2 or MIP-1alpha bioactivity in vivo results in decreased neutrophil influx. These data are also the first demonstration that the C-C chemokine MIP-1alpha is involved in neutrophil recruitment in vivo.

Effect of long-term ethanol consumption on ability to produce cytokine-induced neutrophil chemoattractant-1 in the rat liver and its gender difference

Gut-derived lipopolysaccharide (LPS) may contribute to hepatocellular necrosis in alcoholic hepatitis through neutrophil sequestration in hepatic sinusoids. It is well known that the female has a greater susceptibility to alcoholic liver injury than the male. The aim of the present study was to investigate the effect of long-term ethanol consumption on ability of the liver to produce cytokine-induced neutrophil chemoattractant-1 (CINC-1), the most potent neutrophil-chemokine in rats, after LPS administration. Furthermore, we aimed to evaluate the gender difference in this ability. Male and female rats were pair-fed a liquid diet containing 36% of the total calories as ethanol or dextrose for 6 to 8 weeks. They were given LPS intravenously, and chemokine mRNA expression in the liver was evaluated after 2 and 6 hr. To study the organ or chemokine specificity, CINC-1 mRNA expression in the spleen and monocyte chemoattractant protein (MCP)-1 mRNA level were also determined. Serum ALT activity started to increase between 2 and 6 hr. Female rats fed an ethanol diet showed significantly higher ALT activity 6 hr after LPS injection than the male rats. CINC-1 mRNA expressions in the liver after 2 and 6 hr were significantly higher in the ethanol-fed group, compared with the pair-fed control. Female rats fed an ethanol diet showed a significantly higher level of CINC-1 mRNA in the liver than the male rats 2 hr after LPS injection. CINC-1 levels in the liver homogenates paralleled closely its mRNA expression, whereas its concentrations in sera did not correlate with those in the liver. Neither CINC-1 mRNA expression in the spleen nor MCP-1 mRNA expression in the liver was affected by ethanol feeding or gender. An additional experiment using the gonadectomized rats fed an ethanol diet showed that gonadectomy totally abolished the gender difference in CINC-1 mRNA of the liver. We conclude that CINC-1 induction in the liver may be responsible for LPS-induced hepatitis in the ethanol-fed rats, and that the difference in ability to produce CINC-1 between males and females is one important factor that may partly account for the gender difference of alcoholic liver disease.

Prolonged survival of rat hepatic allografts treated with a pretransplant donor-specific blood transfusion is associated with reduced cytokine-induced neutrophil chemoattractant expression

BACKGROUND

One intravenous injection of freshly heparinized donor blood 7 days before transplantation significantly prolongs hepatic allograft survival from ACI (RT1a) to LEW [RT1(1)] rats. The aim of this study was to investigate hepatic allograft expression of neutrophil chemoattractant and tumor necrosis factor in immunologic unresponsiveness.

METHODS AND RESULTS

Cytokine-induced neutrophil chemoattractant levels in untreated hepatic allografts were significantly higher than in allografts treated with donor-specific transfusion. Additionally, more neutrophils infiltrated untreated than transfusion-treated hepatic allografts. The number of chemoattractant-positive cells was significantly lower in donor-specific transfused allografts than in untreated hepatic allografts. The number of ED1+ mononuclear cells infiltrating portal areas of untreated allografts increased over time and expressed abundant cytokine-induced neutrophil chemoattractant mRNA during acute rejection. This correlated with significantly higher levels of chemoattractant mRNA in untreated allograft livers on postoperative day 5 as compared with transfusion-treated allografts. Serum concentrations of tumor necrosis factor-alpha in untreated hepatic allograft recipients increased over time and peaked on day 7, while those in transfused allografts were maintained at lower levels. Moreover, in vitro chemoattractant production by peritoneal macrophages responded in a dose-dependent manner to tumor necrosis factor-alpha.

CONCLUSION

Donor-specific transfusion treatment decreases tumor necrosis factor-alpha and chemoattractant expression as well as neutrophil accumulation in hepatic allografts.

Cytokine-induced neutrophil chemoattractant gene expression in the rat hypothalamus by osmotic stimulation

Cytokine-induced neutrophil chemoattractant (CINC) is one of the chemokines and has chemotaxity for neutrophils. Recently, we found the presence of stress-sensitive CINC expression in the hypothalamic nuclei such as the paraventricular nucleus. Since CINC was predominantly co-localized with vasopressin in the supraoptic nucleus (SON), we investigated the effect of hyperosmotic challenge on CINC mRNA in the hypothalamus. We found that CINC mRNA expression in the hypothalamus was augmented within 30 min following osmotic stimulation and immediately returned to the basal level. The suckling, which is a stimulation to oxytocin neurons in the SON, has no effect on CINC mRNA expression in the hypothalamus. This is the first evidence that the chemokine in the brain is activated by osmotic stimulation.

Possible participation of macrophage inflammatory protein 2 in neutrophil infiltration in allergic inflammation in rats

Recombinant rat macrophage inflammatory protein 2 (MIP-2) was prepared from E. coli transfected with a glutathione-S-transferase (GST)-MIP-2 fusion protein expression vector. A polyclonal antibody to rat MIP-2 was then obtained from rabbits by immunization with recombinant rat MIP-2. Using the polyclonal antibody which selectively suppressed neutrophil chemotactic activity of MIP-2, the role of MIP-2 in neutrophil infiltration in allergic inflammation in rats was studied. In an air pouch-type allergic inflammation model in rats, neutrophil infiltration into the pouch fluid increased with time after antigen challenge. Neutrophil chemotactic activity in the pouch fluid collected 8 h after antigen challenge was diminished by anti-MIP-2 antibody. In addition, when leukocytes that had infiltrated into the pouch fluid collected 4 h after antigen challenge were incubated, neutrophil chemotactic activity in the conditioned medium increased time-dependently, and the activity was neutralized by anti-MIP-2 antibody. Furthermore, when anti-MIP-2 antibody was injected into the pouch 6 h after antigen challenge, neutrophil infiltration into the pouch fluid during the next 2 h was suppressed. These findings indicate that MIP-2 plays an important role in neutrophil infiltration in rat allergic inflammation.

Pituitary folliculo-stellate-like cell line produces a cytokine-induced neutrophil chemoattractant

In previous studies, we reported that cytokine-induced neutrophil chemoattractant (CINC) was produced in the pituitary gland. Here we investigated the possibility of detection of CINC immunoreactivity in the pituitary folliculo-stellate (FS)-like cell line (TtT/GF). Intense immunoreactivity was observed by immunocytochemistry in the cytoplasm and cell processes of TtT/GF cells. CINC immunoreactivity was detected by an enzyme-linked immunosorbent assay in as little as 3 h after conditioning the medium with TtT/GF cells, and it increased significantly in a time-dependent manner during the first 24 h of the culture. This immunoreactivity could be induced by lipopolysaccharide and tumor necrosis factor-alpha in a time- and dose-dependent manner. We also observed the expression of CINC mRNA in TtT/GF cells and LPS increased CINC mRNA accumulation in TtT/GF cells. These findings indicate that CINC produced by FS cells may play a role as a paracrine factor of the anterior pituitary gland, and TtT/GF will provide a useful model system for studying the regulation of CINC secretion by FS cells.

A stress-sensitive chemokinergic neuronal pathway in the hypothalamo-pituitary system

Recently we found that cytokine-induced neutrophil chemoattractant influenced anterior pituitary hormone release in vitro. These observations prompted us to investigate the possibility of the existence of cytokine-induced neutrophil chemoattractant in the hypothalamus. Immunohistochemistry showed that cytokine-induced neutrophil chemoattractant-like immunoreactivity existed in the paraventricular hypothalamic nucleus, the supraoptic nucleus, both the internal and the external layers of the median eminence and the posterior pituitary. Since the paraventricular hypothalamic nucleus plays a pivotal role in response to stressful stimuli, we examined the effect of a single episode of immobilization stress on cytokine-induced neutrophil chemoattractant messenger RNA expression in the paraventricular hypothalamic nucleus. Immobilization stress induced strong hybridization signals of cytokine-induced neutrophil chemoattractant messenger RNA in the parvocellular and magnocellular subdivision of the paraventricular hypothalamic nucleus within 15 min, and cytokine-induced neutrophil chemoattractant-like immunostaining intensity in the posterior pituitary started to increase around the periphery of the posterior lobe at 30 min after stress and extended to the whole lobe at 1 h after stress. The increase in the serum cytokine-induced neutrophil chemoattractant in response to stress showed a kinetically biphasic pattern. A first phase occurred within 15 min which may be due to an immediate release of stored cytokine-induced neutrophil chemoattractant in the neurohypophysis, since hypophysectomy completely blocked this phase. A second phase may reflect the release of newly synthesized cytokine-induced neutrophil chemoattractant in the paraventricular hypothalamic nucleus and/or peripheral cytokine-induced neutrophil chemoattractant, since hypophysectomy could not reduce this phase. These data suggest that cytokine-induced neutrophil chemoattractant in the paraventricular hypothalamic nucleus was immediately synthesized in response to stress, and then released into the peripheral blood via the hypothalamo-neurohypophysial system, revealing the presence of a stress-sensitive chemokinergic neuronal pathway in the hypothalamo-pituitary system.

Involvement of Interleukin (IL) 8 receptor in negative regulation of myeloid progenitor cells in vivo: evidence from mice lacking the murine IL-8 receptor homologue

Expansion of mature neutrophils has been observed in mice lacking the murine interleukin (IL) 8 receptor homolog [mIL-8Rh(-/-)], and human (hu) IL-8 suppresses proliferation of primitive myeloid cells in vitro and in vivo. To evaluate involvement and relevance of murine IL-8 receptor homolog (mIL-8Rh) in negative regulation of myelopoiesis, we studied mIL-8Rh(-/-) and (+/+) mice raised in a normal or germ-free environment. Immature myeloid progenitors from mIL-8Rh(+/+) mice bred under normal or germ-free conditions were significantly suppressed in vitro by recombinant huIL-8, macrophage inflammatory protein (MIP)-1 alpha, platelet factor (PF) 4, interferon inducible protein (IP) 10, monocyte chemotactic peptide (MCP) 1, and H-ferritin. In contrast, progenitors from mIL-8Rh(-/-) mice were insensitive to inhibition by IL-8, but not to these other chemokines and H-ferritin. Mouse MIP-2, a ligand for mIL-8Rh, suppressed progenitors from normal but not mIL-8Rh(-/-) mice. Under normal environmental conditions, enhanced numbers of myeloid progenitors were found in femur, spleen, and blood of mIL-8Rh(-/-) compared with mIL-8Rh(+/+) mice. Numbers of myeloid progenitors were greatly decreased in mIL-8Rh(-/-)and (+/+) mice in germ-free conditions, and were either not significantly enhanced in mIL-8Rh(-/-) mice compared with (+/+) mice or were only moderately so. Differences in progenitors/organ between a germ-free and normal environment were greater for the mIL-8Rh(-/-) mice. These results document selective insensitivity of myeloid progenitor cells from mIL-8Rh(-/-) mice to inhibition by huIL-8 and mouse MIP-2 and a large expansion of myeloid progenitors in these mice, the latter effect being environmentally inducible. This provides strong support for a negative myeloid regulatory role played by the mIL-8Rh in vivo, whose active ligand may be MIP-2.

Serotype-dependent induction of pulmonary neutrophilia and inflammatory cytokine gene expression by reovirus

Reovirus type 3 Dearing (T3D) causes a prominent neutrophil influx, substantially greater than seen with reovirus type 1 Lang (T1L) in a rat model of viral pneumonia. We sought to measure reovirus-mediated increases in chemokine mRNA expression in pulmonary cells. We found that the neutrophilia induced by T1L and T3D infection in vivo correlated directly with increased levels of chemokine mRNA expression in T3D-infected compared with those of T1IL-infected lungs. In vitro, reovirus-infected normal alveolar macrophages (AMs) and the rat AM cell line NR8383 expressed greater levels of macrophage inflammatory protein 2, KC, and tumor necrosis factor alpha mRNA. A synergism between reovirus and lipopolysaccharide was also detected for macrophage inflammatory protein 2 and KC mRNA expression. Tumor necrosis factor protein secretion was also increased to a greater extent by T3D than by T1L in primary rat AMs and the NR8383 cells. We conclude that the virus-mediated inflammatory cytokine induction suggests a role for these cytokines in the neutrophil influx observed in the rat reovirus pneumonia model.

Induction of cytokine-induced neutrophil chemoattractant (CINC) mRNA in the lungs of septic rats

OBJECTIVE

To study cytokine-induced neutrophil chemoattractant (CINC) mRNA induction in lungs of normal, neutropenic, and adrenalectomized rats after intraperitoneal Escherichia coli lipopolysaccharide (LPS) administration and in cultured rat pulmonary cell lines after exposure to mediators of the septic response.

MATERIALS AND METHODS

Northern blotting was used to assay relative CINC mRNA levels and a colorimetric myeloperoxidase assay was used as a measure of neutrophil infiltration.

RESULTS

After a single dose of LPS, rapid induction of CINC mRNA coincided with neutrophil infiltration into lungs, a response that lasted approximately 12 to 24 hours. Multiple LPS treatments resulted in a similar CINC response, but a more prolonged myeloperoxidase response. CINC mRNA induction in lungs was heightened 30% in adrenalectomized animals and 400% in neutropenic ones. LPS and cytokines induced CINC mRNA in cultured endothelial and epithelial cells.

CONCLUSIONS

Induction of CINC mRNA expression in pulmonary endothelial and/or epithelial cells by systemic LPS or cytokines may play a role in mediating neutrophil infiltration into lungs during sepsis. Markedly increased CINC induction in the lungs of neutropenic animals suggests that neutrophils may act to inhibit expression of this chemoattractant via a negative feedback mechanism.

Neutrophil elastase inhibitor (ONO-5046) decreases cytokine-induced neutrophil chemoattractant after reperfusion of pancreaticoduodenal transplantation in rats

The protective effects of a neutrophil elastase inhibitor (ONO-5046) on reperfusion injury following pancreaticoduodenal transplantation in rats were studied by measuring serum concentrations of cytokine-induced neutrophil chemoattractant (CINC). Male Wistar rats were transplanted with syngeneic pancreaticoduodenal grafts. ONO-5046 was injected intravenously 5 min before vascular clamping and immediately after reperfusion at a dose of 10 mg/kg. No significant differences were observed in the peak serum concentrations of amylase between the groups treated with and treated without ONO-5046. The serum lipase concentrations in the untreated animals increased and peaked 3 hr after reperfusion. ONO-5046 significantly decreased the peak serum lipase concentration. The serum CINC concentrations, which were determined by enzyme-linked immunosorbent assay, increased and peaked 3 hr after reperfusion, decreasing gradually thereafter. However, pretreatment with ONO-5046 significantly inhibited the rise in serum CINC concentrations after reperfusion. Expression of CICN transcripts in the pancrease grafts was evaluated by Northern blot analysis and peaked 3 hr after reperfusion in untreated animals. Pretreatment with ONO-5046 also significantly inhibited the expression of CINC mRNA transcripts in the graft. ONO-5046 significantly decreased the number of neutrophils accumulated in the pancreas graft 24 hr after transplantation. In vitro CINC production by peritoneal macrophages was increased by neutrophil elastase in dose-dependent fashion. However, ONO-5046 decreased CINC production by peritoneal macrophages in response to neutrophil elastase. These results suggest that ONO-5046 prevents early neutrophil accumulation in the pancreas following ischemia/reperfusion of pancreaticoduodenal transplantation.

Glucocorticoid-mediated gene suppression of rat cytokine-induced neutrophil chemoattractant CINC/gro, a member of the interleukin-8 family, through impairment of NF-kappa B activation

The glucocorticoid dexamethasone inhibited the production of the rat cytokine-induced neutrophil chemoattractant CINC/gro, a counterpart of human melanoma growth-stimulating activity that belongs to the interleukin-8 (IL-8) family, in the normal rat kidney epithelial cell line NRK-52E stimulated with interleukin-1 beta (IL-1 beta), lipopolysaccharide, or tumor necrosis factor alpha. The accumulation of CINC/gro mRNA induced by these activators was also decreased comparably by dexamethasone. A nuclear run-on assay revealed that dexamethasone decreased the IL-1 beta-induced transcription of the CINC/gro gene. The half-life of CINC/gro mRNA transcripts did not change significantly after exposure to dexamethasone, suggesting that this glucocorticoid acts mainly at the transcriptional level. Transfection with luciferase expression vectors containing 5'-deleted and mutated CINC/gro gene sequences demonstrated that the 5'-flanking region containing the NF-kappa B binding site is involved in the IL-1 beta- and dexamethasone-induced activation and repression of the CINC/gro gene expression, respectively. Furthermore, a tandem repeat of the NF-kappa B sequence in the CINC/gro gene conferred the inducibility by IL-1 beta and suppression of luciferase activity by dexamethasone. In an electrophoretic mobility shift assay, dexamethasone diminished the IL-1 beta-induced formation of NF-kappa B complexes, which consisted of p65 and p50. Western blotting revealed that dexamethasone inhibited the IL-1 beta-induced translocation of p65 from the cytoplasm into the nucleus, while the nuclear level of NF-kappa B p50 remained almost unchanged. In addition, the degradation of I kappa B-alpha induced by IL-1 beta was not inhibited by dexamethasone. These results indicated that the suppression of the CINC/gro gene transcription by glucocorticoid occurs through the impairment of NF-kappa B activation, possibly by interference with the translocation of NF-kappa B p65 from the cytoplasm into the nucleus, thereby suppressing transactivation of the CINC/gro gene.

Modulation of antibody-mediated glomerular injury in vivo by IL-1ra, soluble IL-1 receptor, and soluble TNF receptor

The severity of glomerular injury in the heterologous phase of NTN is dependent on proinflammatory cytokines including TNF alpha and IL-1 beta, and can be enhanced by LPS. We have previously shown that passive immunization against IL-1 beta and TNF partially abrogated the LPS effect in this model. In the present work, we have assessed the effects on glomerular injury of blocking and binding of IL-1 to its receptor by rh IL-1 receptor antagonist (IL-1ra) and by neutralizing IL-1 and TNF with rm soluble IL-1 receptor type1 (sIL-1Rt1) and rh sTNF receptor (sTNFr p55), respectively. Pretreatment with either IL-1ra, sIL-1Rt1, or sTNFr partially abrogated the effects of LPS and reduced albumin excretion from 45 +/- 8, 66 +/- 9, and 101 +/- 17 mg/24 hr at 13 +/- 4 (P < 0.02), 14 +/- 4 (P < 0.001), and 21 +/- 7 mg/24 hr (P < 0.001), respectively. Similarly, these inhibitors reduced the prevalence of glomerular capillary thrombi and the intensity of glomerular neutrophil infiltration. Glomerular thrombosis was reduced from 18 +/- 3%, 28 +/- 5%, and 25 +/- 7% to 3 +/- 2% (P < 0.002), 6 +/- 2% (P < 0.001), and 3 +/- 2 (P < 0.001), respectively, and glomerular neutrophil infiltration was reduced from 46 +/- 3, 54 +/- 2, 59 +/- 8 to 19 +/- 2 (P < 0.001), 25 +/- 2 (P < 0.001), and 28 +/- 2 neutrophils/50 glomeruli in section, respectively. Coadministration of both soluble receptors of IL-1 and TNF caused a further decrease in glomerular injury. The protective effect was also noticed at four hours after induction of nephritis, and even when these inhibitors were administered after the LPS injection and at the same time of induction of nephritis. All three treatments reduced circulating TNF concentration (down to 20%, 34%, and 0%, respectively) but without detectable glomerular TNF gene expression. Glomerular IL-1 beta mRNA levels were also reduced by 41%, 53%, and 67%, respectively, when assessed by densitometric analysis of Northern blots. In contrast, the glomerular expression of IL-1ra was not affected by its exogenous administration but was mildly reduced by sIL-1Rt1 and sTNFr, which demonstrates the potential role for host derived IL-1ra as an endogenous negative feedback mediator in the glomerulus. These results confirm the direct involvement of IL-1 and TNF in LPS-enhanced hNTN and demonstrate the potency of these inhibitors in modulating injury even when administered after LPS and in time of induction of nephritis. They were more specific and effective than passive immunization with polyclonal antibodies, and this demonstrates their potential usefulness in the management of nephritis.

Recombinant production and biological properties of rat cytokine-induced neutrophil chemoattractants, GRO/CINC-2 alpha, CINC-2 beta and CINC-3

Recently we found four cytokine-induced neutrophil chemoattractants, CINC-1, CINC-2 alpha, CINC-2 beta and CINC-3/macrophage inflammatory protein 2 (MIP-2), in conditioned medium of granulation tissue obtained from carrageenin-induced inflammation in rats [Nakagawa, H., Komorita, N., Shibata, F., Ikesue, A., Konishi, K., Fujioka, M. & Kato, H. (1994) Biochem. J. 301, 545-550]. In the present report, we describe recombinant production of CINC-2 alpha, CINC-2 beta and CINC-3 in Escherichia coli, and biological properties of these chemokines. Neutrophil chemotactic activities of CINC-2 alpha and 2 beta in vitro were the same as the activity of CINC-1. CINC-3 had an activity comparable to other CINCs, but showed a decrease at high concentrations. Stimulation of neutrophils with CINCs induced an increase in intracellular [Ca2+] dose-dependently. CINC-3 was more potent than the other CINCs and still induced an increase in intracellular [Ca2+] in rat neutrophils stimulated first with other CINCs. CINC-2 alpha, CINC-2 beta and CINC-3 induced a comparable response to CINC-1 in the release of cathepsin G from rat neutrophils. Injection of CINC-2 alpha, 2 beta and 3 into preformed air-pouch on the back of rat induced infiltration of neutrophils to an extent similar to that caused by the injection of CINC-1. These data indicate CINC-2 alpha, 2 beta and 3 as well as CINC-1 are chemoattractants specific for neutrophil in vivo.

Separation of neutrophils from blood in human and laboratory animals and comparison of the chemotaxis

We separated neutrophils from the peripheral blood of the human, monkey, dog, rabbit, rat, hamster, and mouse and investigated their responses to several chemotactic factors to evaluate the species-dependent difference in responsiveness. Heparinized blood was obtained by venipuncture from human, monkey, dog, and rabbit. In the rat, hamster, and mouse, the hetastarch exchange transfusion method was used to increase the neutrophil recovery. After sedimentation of red blood cells, a leukocyte suspension was layered on 5-step discontinuous Percoll gradients of densities from 1.081 to 1.097. We could routinely obtain the fractions containing neutrophils at more than 90% in all of the seven species tested. Chemotaxis assay was performed using a 48-well modified Boyden chamber. Dog neutrophils did not migrate to N-formylmethionyl-leucyl-phenylalamine (fMLP), and dog and rat neutrophil responses to leukotriene B4 (LTB4) were remarkably modest. However, neutrophils from other species showed a high reactivity to fMLP and LTB4. Although neutrophils of all species responded to human recombinant interleukin 8 (hrIL-8), the sensitivity of human and monkey neutrophils to hrIL-8 were higher as compared with other species. Human, dog, and rat neutrophils reacted most to homologous zymosan-activated serum derived respectively from human, dog, and rat serum. The present results show species-dependent differences of neutrophils in chemotactic responses.

Expression of the chemokine superfamily in rheumatoid arthritis

The infiltration of leucocytes into the joint of rheumatoid arthritis (RA) is believed to be mediated by chemotactic factors released by activated cells. In this study, examination was made of the gene expression and production of the chemokine superfamily in RA patients by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoprecipitation. Cultured synovial fibroblasts were found capable of expressing and producing IL-8, GRO, monocyte chemotactic and activating factor (MCAF), macrophage inflammatory protein-1 alpha (MIP-1 alpha), MIP-1 beta and RANTES in response to IL-1 alpha. The expression of IL-8, GRO, MCAF, MIP-1 alpha, and MIP-1 beta was clearly shown to increase in freshly isolated synovial fluid mononuclear cells (SFMC) of RA patients, in contrast to peripheral blood mononuclear cells (PBMC) of RA patients and normal subjects. The gene expression of RANTES appeared to be the same for RA SFMC, RA PBMC, and normal PBMC. Thus, the over-expression of various chemokines may promote the recruitment of inflammatory cells into rheumatoid inflamed joints.

Neutrophil and B cell expansion in mice that lack the murine IL-8 receptor homolog

Interleukin-8 (IL-8) is a proinflammatory cytokine that specifically attracts and activates human neutrophils. A murine gene with a high degree of homology to the two known human IL-8 receptors was cloned and then deleted from the mouse genome by homologous recombination in embryonic stem (ES) cells. These mice, although outwardly healthy, had lymphadenopathy, resulting from an increase in B cells, and splenomegaly, resulting from an increase in metamyelocytes, band, and mature neutrophils. Thus, this receptor may participate in the expansion and development of neutrophils and B cells. This receptor was the major mediator of neutrophil migration to sites of inflammation and may provide a potential therapeutic target in inflammatory disease.

Identification of cytokine-induced neutrophil chemoattractants (CINC), rat GRO/CINC-2 alpha and CINC-2 beta, produced by granulation tissue in culture: purification, complete amino acid sequences and characterization

Four basic neutrophil chemotactic factors (chemokines) have been purified from conditioned medium of granulation tissue obtained from carrageenin-induced inflammation in the rat. On the basis of their N-terminal amino acid sequences, one of the chemokines was identical with rat GRO/cytokine-induced neutrophil chemoattractant (CINC) which we reported previously, and another was identical with rat macrophage inflammatory protein-2 (MIP-2). Two other chemokines were novel chemoattractants related to MIP-2. The novel chemokines are referred to as rat GRO/CINC-2 alpha and CINC-2 beta, and consequently CINC and rat MIP-2 are renamed rat GRO/CINC-1 and CINC-3 respectively. The complete amino acid sequences of purified CINC-2 alpha and CINC-3 were determined by analysis of the fragments isolated from proteinase V8-treated CINCs. The cDNA for CINC-2 beta was cloned by reverse transcription/PCR amplification using specific primers starting with total RNA extracted from lipopolysaccharide-stimulated rat macrophages. A comparison of the amino acid sequence encoded by the cDNA with the N-terminal amino acid sequence of purified CINC-2 beta revealed that mature CINC-2 beta is a 68-residue chemoattractant produced by cleavage of a 32-residue signal peptide. The difference in amino acid sequences between CINC-2 alpha and CINC-2 beta consisted of only three C-terminal residues. Rat GRO/CINC-2 alpha is a major chemokine, and the four purified chemokines have similar chemotactic activity, suggesting that they contribute to neutrophil infiltration into inflammatory sites in rats.