Structure of the gene encoding rat neutrophil chemo-attractant Gro

Sickness behaviour is induced by a peripheral CXC-chemokine also expressed in multiple sclerosis and EAE

Non-CNS chemokine production may contribute to previously unrecognised components of Multiple Sclerosis (MS) pathology. Here we show that IL-8, a neutrophil chemoattractant, is significantly increased in serum from individuals with MS, and that the rodent homolog of IL-8 (CXCL1) is expressed in the liver in experimental autoimmune encephalomyelitis (EAE), a rodent model of MS. The hepatic expression of CXCL1 in EAE is accompanied by neutrophil recruitment to the liver, and we show that this recruitment is a feature of post mortem liver tissue from MS patients, which is a previously unrecognised phenomenon. We speculated that the presence of peripheral CXC-chemokine expression might contribute to the sickness behaviours associated with MS, which are a significant contributor to morbidity. Peripheral, but not central, administration of CXCL1 to Wistar rats inhibited spontaneous activity in the open field and burrowing behaviour in a dose-dependent manner (5-45 microg). The expression of CXCL1 by the liver and the recruitment of neutrophils can be modelled by the intracerebral injection of IL-1beta. Here, we found that interferon-beta (IFN-beta) pretreatment significantly inhibited hepatic CXCL1 production and neutrophil recruitment to the liver induced by the microinjection of IL-1beta into the brain. Thus while the mechanism by which IFN-beta therapy suppresses disease in MS remains unclear, the data presented here suggests that the inhibition of hepatic chemokine synthesis may be a contributing factor.

Natural antisense transcript stabilizes inducible nitric oxide synthase messenger RNA in rat hepatocytes

During inflammation, inducible nitric oxide synthase (iNOS) is induced to generate the important mediator nitric oxide (NO). Interleukin 1beta (IL-1beta) induces iNOS messenger RNA (mRNA), iNOS protein, and NO in rat hepatocytes. We found that the stability of iNOS mRNA changed during the induction and that the antisense (AS) strand corresponding to the 3'-untranslated region (3'UTR) of iNOS mRNA was transcribed from the iNOS gene. Expression levels of the iNOS AS transcript correlated with those of iNOS mRNA. The 1.5-kilobase region 3'-flanking to iNOS gene exon 27 was involved in IL-1beta induction. Knockdown experiments suggest that sense oligonucleotides to iNOS mRNA significantly reduced iNOS mRNA levels in the hepatocytes by blocking the interaction between iNOS mRNA and the AS transcript. Overexpression of iNOS AS transcript stabilized the reporter luciferase mRNA through the fused iNOS mRNA 3'UTR. These results together with the data in a yeast RNA-hybrid assay suggested that the iNOS AS transcript interacted with iNOS mRNA and stabilized iNOS mRNA. The iNOS mRNA colocalized with the AU-rich element-binding protein HuR, a human homolog of embryonic lethal-abnormal visual protein, and heterogeneous nuclear ribonucleoprotein L (hnRNP L) in the cytoplasm of rat hepatocytes. Interaction assays further revealed that the iNOS AS transcript interacted with HuR, which interacted with hnRNP L, suggesting that iNOS mRNA, the AS transcript, and the RNA-binding proteins may mutually interact.

CONCLUSION

The natural AS transcript of the iNOS gene interacts with iNOS mRNA and may play an important role in the stability of iNOS mRNA. This RNA-RNA interaction may be a new therapeutic target for NO-mediating inflammatory diseases.

High glucose stimulates GRO secretion from rat microglia via ROS, PKC, and NF-kappaB pathways

Hyperglycemia causes direct neuronal damage in diabetic encephalopathy. Microglia have been found to be activated in diabetic encephalopathy, presumably mediating and amplifying neuron degeneration. Chemokine IL-8 plays an important role in the pathogenesis of encephalopathy. Therefore, we investigated whether high glucose could activate microglia and stimulate IL-8 secretion and if so, the possible mechanisms that were involved. ELISA results showed that treatment with high glucose (35 mM) compared with treatment with low glucose (10 mM) time-dependently elevated secretion of GRO (the rat ortholog of human IL-8) in primary cultured rat microglia. Real-time PCR results showed GRO mRNA expression also increased in response to high glucose in a time-dependent manner. These effects were specific to high glucose because the osmolality control had no such effect. High-glucose treatment stimulated the formation of ROS, as seen in the DCF fluorescence assay, increased phosphorylation of PKC, as seen in the Western blot analysis, and activated NF-kappaB, as seen in the luciferase reporter assay. In addition, treatment with the ROS scavenger NAC (2 mM) significantly reduced the high glucose-induced phosphorylation of PKC and GRO secretion. Treatment with the PKC activator PMA (10-50 nM) stimulated GRO secretion, and the PKC inhibitors calphostin C (300 nM) or chelerythrine (1 microM) attenuated the high glucose-induced GRO secretion. Furthermore, the NF-kappaB inhibitors MG132 (10 microM) or PDTC (5 microM) completely blocked the high glucose-induced GRO secretion. In conclusion, high glucose induces GRO secretion and mRNA expression in activated rat microglia, which is mediated by the ROS, PKC, and NF-kappaB pathways. High glucose-induced IL-8 production by microglia may contribute to diabetic encephalopathy.

Ascorbic Acid Deficiency Stimulates Hepatic Expression of Inflammatory Chemokine, Cytokine-Induced Neutrophil Chemoattractant-1, in Scurvy-Prone ODS Rats

ODS rat has a hereditary defect in ascorbic acid biosynthesis and is a useful animal model for elucidating the physiological role of ascorbic acid. We previously demonstrated by using ODS rats that ascorbic acid deficiency changes the hepatic gene expression of acute phase proteins, as seen in acute inflammation. In this study, we investigated the effects of ascorbic acid deficiency on the production of inflammatory chemokine, cytokine-induced neutrophil chemoattractant-1 (CINC-1), in ODS rats. Male ODS rats (6 wk of age) were fed a basal diet containing ascorbic acid (300 mg/kg diet) or a diet without ascorbic acid for 14 d. Obvious symptoms of scurvy were not observed in the ascorbic acid-deficient rats. Ascorbic acid deficiency significantly elevated the serum concentration of CINC-1 on d 14. The liver and spleen CINC-1 concentrations in the ascorbic acid-deficient rats were significantly elevated to 600% and 180% of the respective values in the control rats. However, the lung concentration of CINC-1 was not affected by ascorbic acid deficiency. Ascorbic acid deficiency significantly elevated the hepatic mRNA level of CINC-1 (to 480% of the value in the control rats), but not the lung mRNA level. These results demonstrate that ascorbic acid deficiency elevates the serum, liver and spleen concentrations of CINC-1 as seen in acute inflammation, and suggest that ascorbic acid deficiency stimulate the hepatic CINC-1 gene expression.

Hepatocyte growth factor stimulates the induction of cytokine-induced neutrophil chemoattractant through the activation of NF-kappaB in rat hepatocytes

BACKGROUND

Recent evidence indicates that CXC chemokines such as human interleukine-8 (IL-8) and rat cytokine-induced neutrophil chemoattractant (CINC) have mitogenic and anti-apoptotic functions in addition to their chemotactic activity toward neutrophils. In the liver, hepatocyte growth factor (HGF) is implicated as a mitogen in the regeneration of liver. However, little is known the interaction between HGF and CXC chemokines during liver injury, repair and regeneration. We hypothesized that HGF may stimulate the expression of such chemokines, which contributes to mitogenic action in liver regeneration.

MATERIALS AND METHODS

Primary cultured rat hepatocytes were treated with recombinant human HGF (rhHGF), in the absence and presence of calpain inhibitor-1 (CI-1), genistein or anti-CINC-1 antibody. Levels of CINC-1 and its mRNA, tyrosine phosphorylation of HGF receptor (c-Met), the activation of transcription factor, nuclear factor-kappaB (NF-kappaB), and activities of DNA synthesis were measured.

RESULTS

rhHGF enhanced the production of CINC-1 time- and dose-dependently, which followed the increased levels of CINC-1 mRNA. Under the same conditions, rhHGF increased the tyrosine phosphorylation of c-Met. The electrophoretic mobility shift assay revealed that rhHGF activated the nuclear translocation of NF-kappaB and its DNA binding. Proteasome inhibitor (CI-1) blocked the NF-kappaB activation and the CINC-1 production. The tyrosine kinase inhibitor (genistein) inhibited the activities of CINC-1 production and the DNA synthesis stimulated by rhHGF. However, the treatment of anti-CINC-1 antibody had no effect on the DNA synthesis.

CONCLUSIONS

These results demonstrate that rhHGF can stimulate the induction of CINC-1 gene expression through the activation of NF-kappaB via its receptor c-Met in hepatocytes. Although CINC-1 seems to be not associated with the enhancement of DNA synthesis by rhHGF, it cannot negate the possibility that CINC-1 may contribute to liver repair and regeneration.

Effects of CXC chemokines on neutrophil activation and sequestration in hepatic vasculature

The initiating step of neutrophil-induced cytotoxicity in the liver is the recruitment of these phagocytes into sinusoids. The aim of our study was to compare the efficacy of systemic exposure with individual inflammatory mediators on neutrophil activation and sequestration in the hepatic vasculature of C3Heb/FeJ mice as assessed by flow cytometry and histochemistry, respectively. The CXC chemokine macrophage inflammatory protein-2 (MIP-2; 20 microg/kg) induced a time-dependent upregulation of Mac-1 (318% at 4 h) and shedding of L-selectin (41% at 4 h). MIP-2 treatment caused a temporary increase of sinusoidal neutrophil accumulation at 0.5 h [97 +/- 6 polymorphonuclear leukocytes (PMN)/50 high-power fields (HPF)], which declined to baseline (8 +/- 2) at 4 h. The CXC chemokine KC was largely ineffective in activating neutrophils or recruiting them into the liver. Cytokines (tumor necrosis factor-alpha and interleukin-1alpha) and cobra venom factor substantially increased Mac-1 expression and L-selectin shedding on neutrophils and caused stable sinusoidal neutrophil accumulation (170-220 PMN/50 HPF). Only cytokines induced venular neutrophil margination. Thus CXC chemokines in circulation are less effective than cytokines or complement in activation of neutrophils and their recruitment into the hepatic vasculature in vivo.

A neutrophil elastase inhibitor (ONO-5046) reduces neurologic damage after spinal cord injury in rats

In view of a cytoprotective effect of elastase inhibitor on chemokine-mediated tissue injury, we examined the neuroprotective effect of ONO-5046, a specific inhibitor of neutrophil elastase, in rats with spinal cord injury. Standardized spinal cord compression markedly increased cytokine-induced neutrophil chemo-attractant (CINC)-1 mRNA and protein. Their increases correlated with neurologic severity of injured rats. Immunohistochemically, CINC-1 protein was detected sequentially in vascular endothelial cells at 4 h, in perivascular neutrophils at 8 h, and in neutrophils infiltrating into cord substance at 12 h. Pretreatment with ONO-5046 (50 mg/kg) markedly ameliorated motor disturbance in injured rats, and reduced CINC-1 protein and mRNA expression. ONO-5046 also significantly reduced the increase of neutrophil accumulation or infiltration estimated by myeloperoxidase activity, and the extent of vascular permeability by Evans blue extravasation in the injured cord segment in comparison to control animals receiving vehicle. These results suggest that CINC-1 contributed to inflammation in rat spinal cord injury and ONO-5046 attenuated neurologic damage partly by blocking CINC-1 production of the chemoattractant, preventing neutrophil activation and vascular endothelial cell injury.

Up-regulation of prostaglandin E receptor EP2 and EP4 subtypes in rat synovial tissues with adjuvant arthritis

To evaluate the role of the prostaglandin E receptor (EP) subtypes in the development of inflammatory synovitis, we examined EP subtype mRNA distribution in the synovial tissue of rats with adjuvant arthritis and the effect of selective EP agonists on cytokine production by cultured rat synovial cells. We used reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization to measure the level of EP subtype (EP1, EP2, EP3, and EP4) mRNA expression in synovial tissues and cultured synovial cells from the arthritic joints of rats. RT-PCR and ELISA were used to analyse the effects of two selective EP agonists on IL-6 production by cultured rat synovial cells. EP2 and EP4 mRNA expression in inflamed synovial tissues was up-regulated. EP2 and EP4 mRNA were co-expressed in synovial macrophages and fibroblasts in inflamed tissues. EP4 and EP2 agonists both inhibited IL-1-induced IL-6 production. Our results suggest that prostaglandin E2 regulates the functions of synovial macrophages and fibroblasts through EP2 and EP4, which are induced by inflammatory stimuli in rats with adjuvant arthritis.

CINC blockade prevents neutrophil Ca(2+) signaling upregulation and gut bacterial translocation in thermal injury

In this study, we have evaluated the role of cytokine-induced neutrophil chemoattractant (CINC), in the upregulation of neutrophil Ca(2+) signaling in neutrophils from thermally injured rats treated with anti-CINC antibody. Additionally, we have determined the effect of the treatment with CINC antibody on the accumulation of activated neutrophils in the intestinal wall, and the effect of such accumulation on gut bacterial translocation. Measurements of myeloperoxidase (MPO) activity and immunohistochemical localization of neutrophils determined neutrophil sequestration in the rat intestine. Agar culture analyses and a specific Escherichia coli beta-galactosidase gene polymerase chain reaction was carried out to detect gut indigenous bacterial invasion into intestinal wall and extraintestinal mesenteric lymph nodes (MLN). The results showed that pretreatment of rats with anti-CINC antibody attenuated the thermal injury-induced enhancement in [Ca(2+)](i) responses in neutrophils both in the basal and Formyl-Met-Leu-Phe stimulated conditions. Moreover, treatment with the CINC antibody decreased neutrophil infiltration into the gut and attenuated thermal injury-caused translocation of bacteria into the MLN.

Neutrophil chemoattractant 2 beta regulates expression of the Reg gene in injured gastric mucosa in rats

BACKGROUND & AIMS

Regenerating (Reg) protein has a trophic effect on gastric mucosal cells. We have shown that Reg gene expression is increased in enterochromaffin-like (ECL) cells during the healing of damaged gastric mucosa around mucosal erosion. This study was designed to explore the stimulants of Reg expression during the healing of gastric mucosal damage.

METHODS

Time course changes of the expression of genes for various proinflammatory cytokines and Reg were investigated after induction of gastric mucosal lesions in rats. The direct effect of proinflammatory cytokines on Reg gene expression and Reg protein production were investigated in vitro using counterflow elutriation-enriched rat ECL cells. CXC receptor 2 (CXCR-2) expression was investigated in ECL cells by reverse-transcription polymerase chain reaction. Reg gene expression was also investigated in rats treated by the neutralizing antibody of cytokine-induced neutrophil chemoattractant (CINC-2 beta).

RESULTS

During healing, the gene expression of several proinflammatory cytokines and Reg was markedly augmented. Among the proinflammatory cytokines, CINC-2 beta is the only cytokine in which augmented expression preceded the increase of Reg gene expression. In rats treated with CINC-2 beta neutralizing antibody, the augmentation of Reg gene expression was significantly inhibited. When ECL cells were incubated with these proinflammatory cytokines, CINC-2 beta dose-dependently increased Reg messenger RNA and Reg protein in ECL cells. CXCR-2 was identified in isolated ECL cells.

CONCLUSIONS

CINC-2 beta, expressed in damaged gastric mucosa, stimulates the production of Reg protein in ECL cells via CXCR-2 and may be involved in the accelerated healing of injured gastric mucosa.

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.

Alcoholic fatty liver differentially induces a neutrophil-chemokine and hepatic necrosis after ischemia-reperfusion in rat

Primary graft nonfunction of steatotic liver allograft is one of the factors causing shortage of donor livers. Ischemia/reperfusion (I/R) injury is an important contributory factor to primary graft nonfunction. In this study, we investigated the complex chain of events from transcription factor activation to necrosis through cytokine induction and apoptosis in steatotic rat liver after warm I/R. Rats with alcoholic or nonalcoholic fatty liver were subjected to hepatic warm I/R and compared with control rats. Rats fed an ethanol diet for 6 to 8 weeks developed severe hepatic necrosis accompanied by increased neutrophil recruitment after I/R, compared with rats with nonalcoholic fatty liver or control. Hepatic apoptosis as assessed by DNA fragmentation at 4 hours after I/R, however, increased to a similar degree in each of the 2 fatty liver models compared with the control. Alcoholic fatty liver exposed to I/R showed a rapid increase in nuclear factor-kappaB (NF-kappaB) binding activity at 1 hour after I/R, which preceded an increased expression of tumor necrosis factor alpha (TNF-alpha) and cytokine-induced neutrophil chemoattractant-1 (CINC-1). In contrast, nonalcoholic fatty liver did not show such potentiation of either NF-kappaB activation or cytokine induction after I/R. Our results have indicated that alcoholic fatty liver may differentially induce CINC-1 production and hepatic necrosis after I/R. Furthermore, our results suggest that apoptosis per se does not always lead to necrosis in the liver following I/R.

Cytokine and chemokine induction using cell wall component and toxin derived from gram-positive bacteria in the rat middle ear

Lipoteichoic acid (LTA) is one of the components present within the cell wall layer of most gram-positive bacteria. It plays an important role in the initiation and progression of bacterial infection. In this study, we performed a rat middle ear and nasal perfusion with LTA purified from two different gram-positive bacterial species. Using ELISA and RT-PCR, the production and mRNA expression of rat chemokine, GRO/CINC-1, proinflammatory cytokine, TNF-alpha, in rat middle ear lavage and mucosa were investigated. GRO/CINC-1 in middle ear lavage was produced by stimulation of LTA in a time-dependent fashion; however, TNF-alpha production into the lavage was not detectable using ELISA assay. The mRNA expressions of GRO/CINC-1 and TNF-alpha in the middle ear mucosa were both induced after LTA and exotoxin exposures. The expression of IL-10 mRNA was also induced after 6 h of LTA and exotoxin exposures. The profile of the production of GRO/CINC-1 and TNF-alpha in rat nasal lavage was similar to that in the middle ear; however, the mRNA expressions of GRO/CINC-1, TNF-alpha and IL-10 in the nasal mucosa were different from those in the middle ear mucosa. These results suggest that the cell wall component and exotoxin of gram-positive bacteria can induce several cytokines in vivo and play an important role in the initiation of the inflammatory cascade in the middle ear.

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.

Inhibition of ozone-induced lung neutrophilia and nuclear factor-kappaB binding activity by vitamin A in rat

Vitamin A binds to retinoic acid receptors, which in turn may interact with other transcription factors. We determined its effect (2500 and 5000 IU/kg) on nuclear factor-kappaB binding activity in the lung, airway inflammation and bronchial hyperresponsiveness in rats exposed to ozone. Ozone (3 ppm, 3 h) caused neutrophil influx into bronchoalveolar lavage fluid (16.2+/-0.8 x 10(5) cells/ml, p < 0.01) and bronchial hyperresponsiveness (-logPC200ACh = 2.54+/-0.19, p < 0.05, compared to control animals, respectively). Vitamin A inhibited this neutrophilia dose-dependently together with the increased DNA-binding activity of nuclear factor-KB in lung extracts. Vitamin A did not affect bronchial hyperresponsiveness at both doses. Vitamin A inhibits ozone-induced neutrophilic inflammation through a reduction in nuclear factor-kappaB DNA binding activity.

Essential role of alveolar macrophages in intrapulmonary activation of NF-kappaB

Acute inflammatory injury in rat lung induced by deposition of immunoglobulin G immune complexes requires expression of cytokines and chemokines as well as activation of the transcription factor nuclear factor (NF)-kappaB. There is little direct evidence regarding the role of alveolar macrophages in these activation events. In the present studies, rat lungs were depleted of alveolar macrophages by airway instillation of liposome-encapsulated dichloromethylene diphosphonate. These procedures, which greatly reduced the number of retrievable alveolar macrophages, suppressed activation of lung NF-kappaB in the inflammatory model. In addition, bronchoalveolar lavage levels of tumor necrosis factor-alpha (TNF-alpha) and the CXC chemokine, macrophage inflammatory protein-2, were substantially reduced. In parallel, upregulation of the lung vascular adhesion molecule, intercellular adhesion molecule-1, was greatly reduced by intrapulmonary instillation of phosphonate-containing liposomes. Neutrophil accumulation and development of lung injury were also substantially diminished. Lung instillation of TNF-alpha in alveolar macrophage-depleted rats restored the NF-kappaB activation response in whole lung. These data suggest that, in this inflammatory model, initial activation of NF-kappaB occurs in alveolar macrophages and the ensuing production of TNF-alpha may propagate NF-kappaB activation to other cell types in the lung.

Chemokine and cell adhesion molecule mRNA expression and neutrophil infiltration in lipopolysaccharide-induced hepatitis in ethanol-fed rats

Neutrophil infiltration is a feature of alcoholic hepatitis (AH), and although the mechanism by which this occurs is unclear, it may involve a chemotactic gradient. We used lipopolysaccharide (LPS) to induce, in ethanol-fed rats, liver damage similar to that seen in AH. To our knowledge, this study is the first to examine the effect of ethanol on LPS-stimulated chemokine mRNA expression in this model. Hepatic cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1beta, MIP-2, and eotaxin mRNA levels were elevated 1 to 3 hr post-LPS in both groups. Maximal expression of MIP-2 and MCP-1 mRNA was higher in ethanol-fed rats 1 hr post-LPS, whereas CINC-2 mRNA expression was elevated above controls at 12 to 24 hr. Hepatic intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 mRNA levels were elevated in both groups at 1 hr, whereas L-selectin expression in ethanol-fed rats was elevated above controls at 12 to 24 hr. Hepatic neutrophil infiltration was highest during maximal hepatocyte necrosis. These data suggest that cell adhesion molecules, in conjunction with elevated cytokines and the subsequently induced chemokines, may assist in the formation of a chemotactic gradient within the liver, causing the neutrophil infiltration seen both in this model and possibly in AH.

Regulation of Acute Lung Inflammatory Injury by Endogenous IL-13

Using IgG immune complex deposition to trigger acute lung inflammation in rats, we have previously shown that exogenously administered IL-13 suppresses the acute inflammatory response. In the same model, expression of both mRNA and protein for IL-13 has now been detected. Treatment of rats with Ab to IL-13 accentuated the inflammatory response, with significant increases in lung vascular permeability and in the number of neutrophils in bronchoalveolar lavage fluids. In the presence of anti-IL-13, activation of the transcription factor, NF-κB, was significantly increased in lung. In addition, anti-IL-13 caused significant increases in bronchoalveolar lavage levels of TNF-α, macrophage inflammatory protein-2, and cytokine-inducible neutrophil chemoattractant but no changes in lung vascular ICAM-1. These data suggest that during lung inflammation endogenous IL-13 regulates NF-κB activation and related cytokine/chemokine generation, all of which determines the intensity of the lung inflammatory response.

Induction of cytokine-induced neutrophil chemoattractant in response to various stresses in rat C6 glioma cells

The effect of stress on the production of cytokine-induced neutrophil chemoattractant (CINC) was examined in rat C6 glioma cells. We studied the production of CINC, an interleukin-8 (IL-8) family protein, with bacterial endotoxin, H2O2, and tumor necrosis factor-alpha (TNF-alpha). Each stress induced CINC mRNA in a concentration-dependent manner. Since stress activates the protein kinases regulating nuclear transcription factors, we examined the effects of protein kinase inhibitors and the over-expression of dominant-negative Ras on CINC mRNA expression. Neither over-expression of dominant-negative Ras nor pretreatment with PD98059 (MEK-1 inhibitor), SB203580 (p38MAPK inhibitor), or GF109203X (protein kinase C (PKC) inhibitor) altered stress-induced CINC mRNA expression. This suggests that the Ras-MAPK, p38MAPK, and PKC pathways are not involved in CINC mRNA expression in glial cells. On the other hand, pretreatment with herbimycin A, a potent tyrosine kinase inhibitor, or Ro31-8220, a non-selective serine/threonine kinase inhibitor, suppressed stress-induced CINC mRNA expression. This indicates that stress-induced CINC mRNA expression is mediated by herbimycin A-, or Ro31-8220-sensitive kinases in glial cells. Since stress activates NF-kappaB and NF-IL6, we examined that the effect of herbimycin A, which suppresses CINC mRNA expression, on NF-kappaB and NF-IL6 activation. Herbimycin A suppressed NF-kappaB but not NF-IL6. These results suggest that in rat glial cells, the factors that induce CINC mRNA expression are mediated by herbimycin A-sensitive NF-kappaB activation, but not through the PKC, Ras-MAPK or p38 MAPK pathways.

Immunosuppressants decrease neutrophil chemoattractant and attenuate ischemia/reperfusion injury of the liver in rats

BACKGROUND

Neutrophils may play an important role in the development of liver ischemia/reperfusion injury. We investigated the effects of the immunosuppressants azathioprine (AZA), cyclosporine A (CsA), tacrolimus (FK506), and rapamycin (RPM) on the expression of cytokine-induced neutrophil chemoattractant (CINC) after ischemia/reperfusion of the liver.

METHODS

Liver ischemia was induced in male Wistar rats by occluding the portal vein with a microvascular clip for 30 minutes. Rats received two intramuscular injections of AZA (4 mg/kg), CsA (5 mg/kg), FK506 (0.5 mg/kg), or RPM (0.5 mg/kg) 3 and 24 hours before ischemia/reperfusion of the liver.

RESULTS

Serum CINC concentrations in untreated animals increased, peaked 6 hours after reperfusion, and thereafter decreased gradually. Pretreatment with AZA, CsA, FK506, and RPM, however, inhibited the increase in serum CINC concentrations after reperfusion. CINC mRNA in liver tissue increased and peaked 3 hours after reperfusion, but was significantly lower in animals treated with AZA, CsA, FK506, and RPM. In vitro CINC production by Kupffer cells harvested from animals treated with AZA, CsA, FK506, or RPM 3 hours after reperfusion was also significantly lower than that observed in untreated animals. Both myeloperoxidase activity and the number of neutrophils accumulating in the liver 24 hours after reperfusion in animals treated with AZA, CsA, FK506, and RPM were significantly lower than in untreated animals. This correlated with lower serum aspartate transaminase, alanine transaminase, and lactate dehydrogenase levels in animals treated with AZA, CsA, FK506, and RPM 24 hours after reperfusion.

CONCLUSION

The immunosuppressants AZA, CsA, FK506, and RPM reduce neutrophil accumulation and attenuate ischemia/reperfusion injury of the liver.

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.

In vivo induction and regulation of interleukin-8-like chemokine GRO/CINC-1 in rat middle ear

Interleukin-8 possesses chemotactic-activating properties toward neutrophils, and may contribute to the pathogenesis of middle ear inflammation. GRO/CINC-1 is a rat chemokine with structural and functional homology to human interleukin-8, the induction and regulation of which in the middle ear cavity in vivo remains to be established. The production of GRO/CINC-1 in middle ear lavage and gene expression in the middle mucosa was investigated using topical inoculation with lipopolysaccharide (LPS) in the rat in vivo model. GRO/CINC-1 in middle ear lavage showed time- and dose-dependent production under LPS stimulation. The peak of the GRO/CINC-1 production was reached by 4 h after LPS 1 h exposure, whereas the level of production subsequently returned to the level without LPS stimulation at 8 h after LPS stimulation. The topical corticosteroid perfusion in the middle ear after LPS stimulation significantly reduced the production of GRO/CINC-1 in the middle ear cavity compared with that without corticosteroid. At the time of peak production, the expression of GRO/CINC-1 mRNA, evaluated using the polymerase chain reaction, was considerable in the middle ear mucosa. This investigation of the characteristics of interleukin-8-like cytokine in the middle ear cavity using a rat in vivo model has extended the functional concept of chemokines at the initial stage in otitis media.

Role of cytokine-induced neutrophil chemoattractant (CINC) in ozone-induced airway inflammation and hyperresponsiveness

Cytokine-induced neutrophil chemoattractant (CINC) is a rat chemokine with potent chemoattractant effects on neutrophils. We determined the involvement of CINC in ozone-induced airway neutrophilia and bronchial hyperresponsiveness (BHR) in the rat. We found a marked increase in lung CINC messenger RNA (mRNA) within 2 h after cessation of ozone exposure (1 ppm for 3 h), as measured by Northern blot analysis, whereas rats exposed to room air had no detectable CINC mRNA. Ozone exposure induced a significant neutrophilia in bronchoalveolar lavage fluid (BALF) at 24 h after exposure (air-exposed rats: 4.2 +/- 2.0 x 10(4), versus ozone-exposed rats: 16.1 +/- 3.7 x 10(4)); prior treatment with a goat anti-CINC antibody (1 mg, intravenously) suppressed the neutrophilia (3.1 +/- 0.9 x 10(4)). When administered intratracheally, the antibody (230 micrograms) partially inhibited the influx of neutrophils. The increase in bronchial responsiveness to acetylcholine observed after ozone exposure was not inhibited by the anti-CINC antibody. The anti-CINC antibody (1 mg, intravenously) also inhibited BALF neutrophilia induced by exposure to a higher concentration of ozone (3 ppm, 3 h), without an effect on BHR. CINC is an important chemokine causing ozone-induced neutrophil chemoattraction, but is not involved in the induction of ozone-induced BHR. The neutrophil is unlikely to contribute to BHR in this model.

Influence of age on the production of interleukin-8-like chemokine (GRO/CINC-1) in rat nasal mucosa

The ability of the nasal mucosa to produce various cytokines has been shown to correlate closely with the capacity to regulate an inflammatory condition in the nasal cavity. Immune senescence is characterized by a dysregulation of the immune system. This change is reflected by the altered production of cytokines during aging. We measured the in vivo production and gene expression of IL-8-like cytokines (GRO/CINC-1) in nasal lavages and mucosa from young (2- to 4-week-old and 11- to 15-week-old) and older (81-to 98-week-old) rats by using enzyme-linked immunosorbent assays and reverse transcription-polymerase chain reactions. Significant increases of GRO/CINC-1 levels were found in unstimulated nasal lavages of the older rats compared to that of the 2- to 4-week-old animals. GRO/CINC-1 showed time-dependent production with lipopolysaccharide (LPS) stimulation in nasal lavages. The GRO/CINC-1 production reached a plateau by 4 h with LPS in any group. However, the manner of the initial time course showed no significant differences among these three groups. At the time of peak production of GRO/CINC-1, messenger RNA for the GRO/CINC-1 was found to be induced in the nasal mucosa. These findings may be important for understanding the mechanisms of the altered immune response and inflammation in the nasal cavity associated with aging.

Production and gene expression of IL-8-like cytokine GRO/CINC-1 in rat nasal mucosa

Growth-regulated gene product/cytokine-induced neutrophil chemoattractant (GRO/CINC)-1 is a rat chemokine with structural and functional homology to human IL-8. Chemokines are a family of cytokines whose participation in nasal inflammation in vivo remains to be established. Using ELISA and RT-PCR, we investigated the production and gene expression of GRO/CINC-1 in rat nasal lavage and mucosa in vivo. GRO/CINC-1 in nasal lavage was produced by stimulation of LPS, ConA and IL1-beta. GRO/CINC-1 showed time- and dose-dependent production under all stimulants, but was more slowly induced by IL-1 beta. The steady-peak of the GRO/CINC-1 production remained at 3 h with LPS or ConA exposure, whereas it lasted 4 h or more after IL-1 beta exposure. At the time of peak production of GRO/CINC-1, we found that mRNA for the GRO/CINC-1 was induced in the nasal mucosa. The mRNA of the related inflammatory cytokines TNF-alpha and IFN-gamma were also expressed in nasal mucosa with stimulation of these reagents. Thus, this study revealed that exposure to bacterial endotoxin, mitogenic reagent and also IL-1 beta induced the production and gene expression of the neutrophil chemoattractant GRO/CINC-1 in rat nasal mucosa in vivo. This investigation of the characteristics of IL-8 family in nasal mucosa using rat models has extended the functional concept of cytokines in the inflammatory condition of nasal cavity in humans.

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.

The expression of cytokine-induced neutrophil chemoattractants (CINC-1 and CINC-2) in rat peritoneal macrophages is triggered by Fc gamma receptor activation: study of the signaling mechanism

The expression of cytokine-induced neutrophil chemoattractants (CINC-1 and CINC-2) mRNA was studied in rat peritoneal cells stimulated with insoluble IgG/ovalbumin immune complexes. A dose- and time-dependent induction was observed in adherent cells, which was more prominent than that induced by the lipid mediator platelet-activating factor (PAF), comparable to that observed in response to 10 micrograms endotoxin in the absence of lipopolysaccharide (LPS)-binding protein, but lower than that produced by 1 mM dibutyryl cyclic AMP, a compound which stabilized transiently expressed genes containing AU-rich sequences in the 3' untranslated region. Analysis of CINC-1 protein by specific enzyme-linked immunosorbent assay confirmed the presence of CINC-1 in the supernatants at concentrations of approximately 4 nM, 4 h after addition of 100 micrograms/ml immune complexes. CINC-2 beta protein was detectable at a lower concentration (approximately 0.3 nM) under the same conditions. Attempts to relate CINC-1 induction with the pathways for cytoplasmic signaling showed a dissociation of Ca2+ mobilization and protein kinase C activation as judged from the small effect of thapsigargin and the lack of effect of phorbol ester. In contrast, these agents produced a marked mobilization of arachidonate linked to the MAP kinase-dependent activation of cytosolic phospholipase A2. The possible dependence of CINC-1 induction on the autocrine generation of lipid mediators was ruled out by a set of experiments including the use of the PAF receptor antagonist BB823, and the analysis of the effect of free arachidonate and leukotriene B4 on CINC-1 induction. Surprisingly, the inhibitor of leukotriene synthesis MK-886 in the range of concentration 1-10 microM inhibited CINC-1 induction by a mechanism that appears to be independent of its effect on eicosanoid production. Interestingly, CINC-1 induction appeared to be related to protein tyrosine phosphorylation reactions on the basis of both the appearance of several tyrosine-phosphorylated protein bands in lysates from adherent peritoneal cells treated with immune complexes and the complete blockade of CINC-1 induction by treatment with 1 microM herbimycin A, an inhibitor of src protein tyrosine kinases.

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.

Ozone induction of cytokine-induced neutrophil chemoattractant (CINC) and nuclear factor-kappa b in rat lung: inhibition by corticosteroids

We determined in rat lung whether ozone exposure was associated with the expression of the chemokine, cytokine-induced neutrophil chemoattractant (CINC), and of the transcription factor, NF-kappa B. CINC mRNA expression peaked at 2 h after cessation of ozone exposure, and returned to basal levels by 24 h. DNA-binding activity of NF-kappa B showed a marked increase after ozone, maximal at 2 h. Dexamethasone inhibited CINC mRNA and NF-kappa B expression, together with neutrophilic inflammation. Our data supports the concept that ozone leads to NF-kappa B activation which increases CINC mRNA expression. These series of events could lead to neutrophilic inflammation.

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.

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.

Modulation of neutrophil influx in glomerulonephritis in the rat with anti-macrophage inflammatory protein-2 (MIP-2) antibody

The role of the chemokine, macrophage inflammatory protein-2 (MIP-2), during anti-glomerular basement membrane (GBM) antibody (Ab) glomerulonephritis (GN) was studied. Rat MIP-2 cDNA had been cloned previously. Recombinant rat MIP-2 (rMIP-2) from Escherichia coli exhibited neutrophil chemotactic activity and produced neutrophil influx when injected into the rat bladder wall. By using a riboprobe derived from the cDNA and an anti-rMIP-2 polyclonal Ab, MIP-2 was found to be induced in glomeruli with anti-GBM Ab GN as mRNA by 30 min and protein by 4 h, with both disappearing by 24 h. The expression of MIP-2 correlated with glomerular neutrophil influx. A single dose of the anti-MIP-2 Ab 30 min before anti-GBM Ab was effective in reducing neutrophil influx (40% at 4 h, P < 0.01) and periodic acid-Schiff deposits containing fibrin (54% at 24 h, P < 0.01). The anti-rMIP-2 Ab had no effect on anti-GBM Ab binding (paired-label isotope study). Functional improvement in the glomerular damage was evidenced by a reduction of abnormal proteinuria (P < 0.05). These results suggest that MIP-2 is a major neutrophil chemoattractant contributing to influx of neutrophils in Ab-induced glomerular inflammation in the rat.

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.