Rat KC cDNA cloning and mRNA expression in lung macrophages and fibroblasts

Investigating the Abscopal Effects of Radioablation on Shielded Bone Marrow in Rodent Models Using Multimodality Imaging

The abscopal effect is the response to radiation at sites that are distant from the irradiated site of an organism, and it is thought to play a role in bone marrow (BM) recovery by initiating responses in the unirradiated bone marrow. Understanding the mechanism of this effect has applications in treating BM failure (BMF) and BM transplantation (BMT), and improving survival of nuclear disaster victims. Here, we investigated the use of multimodality imaging as a translational tool to longitudinally assess bone marrow recovery. We used positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI) and optical imaging to quantify bone marrow activity, vascular response and marrow repopulation in fully and partially irradiated rodent models. We further measured the effects of radiation on serum cytokine levels, hematopoietic cell counts and histology. PET/CT imaging revealed a radiation-induced increase in proliferation in the shielded bone marrow (SBM) compared to exposed bone marrow (EBM) and sham controls. T₂-weighted MRI showed radiation-induced hemorrhaging in the EBM and unirradiated SBM. In the EBM and SBM groups, we found alterations in serum cytokine and hormone levels and in hematopoietic cell population proportions, and histological evidence of osteoblast activation at the bone marrow interface. Importantly, we generated a BMT mouse model using fluorescent-labeled bone marrow donor cells and performed fluorescent imaging to reveal the migration of bone marrow cells from shielded to radioablated sites. Our study validates the use of multimodality imaging to monitor bone marrow recovery and provides evidence for the abscopal response in promoting bone marrow recovery after irradiation.

NK cells regulate CXCR2+ neutrophil recruitment during acute lung injury

A critical step in the pathogenesis of acute lung injury (ALI) is excessive recruitment of polymorphonuclear neutrophils (PMNs) into the lungs, causing significant collateral tissue damage. Defining the molecular and cellular steps that control neutrophil infiltration and activation during ALI is therefore of important therapeutic relevance. Based on previous findings implicating the transcription factor Tbet in mucosal Th1-inflammation, we hypothesized a detrimental role for Tbet during ALI. In line with our hypothesis, initial studies of endotoxin-induced lung injury revealed a marked protection of Tbet^-/- mice, including attenuated neutrophilia compared to WT counterparts. Surprisingly, subsequent studies identified natural killer (NK) cells as the major source of pulmonary Tbet during ALI. In addition, a chemokine screen suggested that mature Tbet⁺ NK-cells are critical for the production of pulmonary CXCL1 and -2, thereby contributing to pulmonary PMN recruitment. Indeed, both NK-cell Ab depletion and adoptive transfer studies provide evidence for NK cells in the orchestration of neutrophil recruitment during endotoxin-induced ALI. Taken together, these findings identify a novel role for Tbet⁺ NK-cells in initiating the early events of noninfectious pulmonary inflammation.

Pharmacologic resuscitation decreases circulating cytokine-induced neutrophil chemoattractant-1 levels and attenuates hemorrhage-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a complication of hemorrhagic shock (HS). Histone deacetylase inhibitors, such as valproic acid (VPA), can improve survival after HS; however, their effects on late organ injury are unknown. Herein, we have investigated the effects of HS and VPA treatment on ALI and circulating cytokines that may serve as biomarkers for the development of organ injury.

METHODS

Anesthetized Wistar-Kyoto rats (250-300 g) underwent 40% blood volume hemorrhage over 10 minutes followed by 30 minutes of unresuscitated shock and were treated with either VPA (300 mg/kg) or vehicle control. Blood samples were obtained at baseline, after shock, and before death (at 1, 4, and 20 hours; n = 3-4/timepoint/group). Serum samples were screened for possible biomarkers using a multiplex electrochemiluminescence detection assay, and results were confirmed using enzyme-linked immunosorbent assay (ELISA). In addition, lung tissue lysate was examined for chemokine and myeloperoxidase (MPO) levels as a marker for neutrophil infiltration and ALI. Lung cytokine-induced neutrophil chemoattractant-1 (CINC-1; a chemokine belonging to the interleukin-8 family that promotes neutrophil chemotaxis) mRNA levels were measured by real-time polymerase chain reaction studies.

RESULTS

Serum screening revealed that hemorrhage rapidly altered levels of circulating CINC-1. ELISA confirmed that CINC-1 protein was significantly elevated in the serum as early as 4 hours and in the lung at 20 hours after hemorrhage, without any significant changes in CINC-1 mRNA expression. Lung MPO levels were also elevated at both 4 and 20 hours after hemorrhage. VPA treatment attenuated these changes.

CONCLUSION

Hemorrhage resulted in the development of ALI, which was prevented with VPA treatment. Circulating CINC-1 levels rose rapidly after hemorrhage, and serum CINC-1 levels correlated with lung CINC-1 and MPO levels. This suggests that circulating CINC-1 levels could be used as an early marker for the subsequent development of organ inflammation and injury.

The signal peptide sequence impacts the immune response elicited by a DNA epitope vaccine

We examined the effect of two leader sequences, one from a transmembrane molecule (H2-L(d)) and another from a secreted molecule (rat KC chemokine), on the immunogenicity of DNA epitope vaccines. The chemokine leader enhanced vaccine immunogenicity, thus underscoring the importance of the leader sequence in DNA epitope vaccine design.

Vanadium pentoxide induces pulmonary inflammation and tumor promotion in a strain-dependent manner

Background

Elevated levels of air pollution are associated with increased risk of lung cancer. Particulate matter (PM) contains transition metals that may potentiate neoplastic development through the induction of oxidative stress and inflammation, a lung cancer risk factor. Vanadium pentoxide (V₂O₅) is a component of PM derived from fuel combustion as well as a source of occupational exposure in humans. In the current investigation we examined the influence of genetic background on susceptibility to V₂O₅-induced inflammation and evaluated whether V₂O₅ functions as a tumor promoter using a 2-stage (initiation-promotion) model of pulmonary neoplasia in mice.

Results

A/J, BALB/cJ (BALB), and C57BL/6J (B6) mice were treated either with the initiator 3-methylcholanthrene (MCA; 10 μg/g; i.p.) or corn oil followed by 5 weekly aspirations of V₂O₅ or PBS and pulmonary tumors were enumerated 20 weeks following MCA treatment. Susceptibility to V₂O₅-induced pulmonary inflammation was assessed in bronchoalveolar lavage fluid (BALF), and chemokines, transcription factor activity, and MAPK signaling were quantified in lung homogenates. We found that treatment of animals with MCA followed by V₂O₅ promoted lung tumors in both A/J (10.3 ± 0.9 tumors/mouse) and BALB (2.2 ± 0.36) mice significantly above that observed with MCA/PBS or V₂O₅ alone (P < 0.05). No tumors were observed in the B6 mice in any of the experimental groups. Mice sensitive to tumor promotion by V₂O₅ were also found to be more susceptible to V₂O₅-induced pulmonary inflammation and hyperpermeability (A/J>BALB>B6). Differential strain responses in inflammation were positively associated with elevated levels of the chemokines KC and MCP-1, higher NFκB and c-Fos binding activity, as well as sustained ERK1/2 activation in lung tissue.

Conclusions

In this study we demonstrate that V₂O₅, an occupational and environmentally relevant metal oxide, functions as an in vivo lung tumor promoter among different inbred strains of mice. Further, we identified a positive relationship between tumor promotion and susceptibility to V₂O₅-induced pulmonary inflammation. These findings suggest that repeated exposures to V₂O₅ containing particles may augment lung carcinogenesis in susceptible individuals through oxidative stress mediated pathways.

The role of the choroid plexus in neutrophil invasion after traumatic brain injury

Traumatic brain injury (TBI) frequently results in neuroinflammation, which includes the invasion of neutrophils. After TBI, neutrophils infiltrate the choroid plexus (CP), a site of the blood-cerebrospinal fluid (CSF) barrier (BCSFB), and accumulate in the CSF space near the injury, from where these inflammatory cells may migrate to brain parenchyma. We have hypothesized that the CP functions as an entry point for neutrophils to invade the injured brain. Using the controlled cortical impact model of TBI in rats and an in vitro model of the BCSFB, we show that the CP produces CXC chemokines, such as cytokine-induced neutrophil chemoattractant (CINC)-1 or CXCL1, CINC-2alpha or CXCL3, and CINC-3 or CXCL2. These chemokines are secreted both apically and basolaterally from the choroidal epithelium, a prerequisite for neutrophil migration across epithelial barriers. Consistent with these findings, we also provide electron microscopic evidence that neutrophils infiltrate the choroidal stroma and subsequently reach the intercellular space between choroidal epithelial cells. This is the first detailed analysis of the BCSFB function related to neutrophil trafficking. Our observations support the role of this barrier in posttraumatic neutrophil invasion.

CXCR2 Blockade Impairs Angiotensin II–Induced CC Chemokine Synthesis and Mononuclear Leukocyte Infiltration

Objective— Angiotensin II (Ang-II) and mononuclear leukocytes are involved in atherosclerosis. This study reports the inhibition of Ang-II–induced mononuclear cell recruitment by CXCR2 antagonism and the mechanisms involved.

Methods and Results— Ang-II (1 nmol/L, i.p. in rats) induced CXC and CC chemokines, followed by neutrophil and mononuclear cell recruitment. Administration of the CXCR2 antagonist, SB-517785-M, inhibited the infiltration of both neutrophils (98%) and mononuclear cells (60%). SB-517785-M had no effect on the increase in CXC chemokine levels but reduced MCP-1, RANTES, and MIP-1α release by 66%, 63%, and 80%, respectively. Intravital microscopy showed that pretreatment with SB-517785-M inhibited Ang-II–induced arteriolar mononuclear leukocyte adhesion. Stimulation of human umbilical arterial endothelial cells (HUAECs) or whole blood with 1 μmol/L Ang-II induced the synthesis of chemokines. Ang-II increased HUAEC CXCR2 expression, and its blockade caused a significant reduction of MCP-1, -3, and RANTES release, as well as mononuclear cell arrest. Ang-II–induced MIP-1α release from blood cells was also inhibited.

Conclusion— Mononuclear leukocyte recruitment induced by Ang-II is, surprisingly, largely mediated by the CXC chemokines which appear to induce the release of CC chemokines. Therefore, CXC chemokine receptor antagonists may help to prevent mononuclear cell infiltration and the progression of the atherogenic process.

Anti-type II collagen antibody accelerates arthritisvia CXCR2-expressing cells in IL-1 receptor antagonist-deficient mice

Arthritis can be induced in mice by the injection of anti-type II collagen (anti-CII) Ab and LPS. To elucidate the role of IL-1 receptor antagonist (IL-1ra) in Ab-induced arthritis, WT and IL-1ra(-/-) mice were administered anti-CII Ab and LPS. These IL-1ra(-/-) mice developed severe arthritis even at low doses of anti-CII Ab and LPS, while WT mice did not. The cells that invaded the arthritic joints were mainly Gr-1(+) neutrophils, and the number of the cells in the joints remained high over 4 weeks in the IL-1ra(-/-) mice. KC, a ligand for CXCR2, is found in higher levels in the arthritic paws of IL-1ra(-/-) mice compared with the WT, and most of the cells that infiltrated into the joints of the IL-1ra(-/-) mice were CXCR2-expressing neutrophils. Administration of anti-CXCR2 Ab completely inhibited arthritis development. The anti-CXCR2 Ab decreased the number of neutrophils in the blood and also inhibited the migration of neutrophils to KC. These results suggested that the high susceptibility of IL-1ra(-/-) mice to anti-CII Ab-induced arthritis was due to the higher expression of chemotactic factors like KC and the sustained infiltration of CXCR2-expressing neutrophils into the joints.

Cell-based gene therapy experiments in murine experimental autoimmune encephalomyelitis

With the ultimate goal of developing a novel treatment for multiple sclerosis (MS), we have developed a cell-based gene therapy protocol for the treatment of murine experimental autoimmune encephalomyelitis (EAE), a powerful animal model for MS. We have determined that transduced fibroblasts secreting encephalogenic epitopes, when injected into mice with EAE, cause a striking abrogation of disease. Both myelin basic protein (MBP) and proteolipid protein mini-gene constructs expressed in syngeneic fibroblast cells were capable of ameliorating ongoing EAE induced by MBP protein. These experiments are crucial since they suggest that not all encephalogenic epitopes need be secreted for the control of disease. We also demonstrate the success of this protocol when transduced syngeneic, and most importantly, allogeneic cells are sequestered within an implantable chamber. Furthermore, we find that through modifying antigen expression by changing the signal sequence of the mini-gene construct, we were able to significantly reduce the dose of cells required for treatment. These improvements to the mini-gene delivery system are critical for the eventual translation of our protocol to the clinic.

Effect of boldine, secoboldine, and boldine methine on angiotensin II-induced neurtrophil recruitment in vivo

Angiotensin-II (Ang-II) has inflammatory activity and is involved in different diseases associated with the cardiovascular system. This study has evaluated the effect of boldine (B), and two phenanthrene alkaloids semisynthesized by us, secoboldine (SB) and boldine methine (BM), on Ang-II-induced neutrophil recruitment. Intraperitoneal administration of 1 nM Ang-II induced significant neutrophil accumulation, which was maximal at 4-8 h. BM inhibited neutrophil infiltration into the peritoneal cavity at 4 h and 8 h by 73% and 77%, respectively, SB at 8 h by 55%, and B had no effect on this response. Although BM inhibited the release of cytokine-inducible neutrophil chemoattractant/keratinocyte-derived chemokine, macrophage inflammatory protein-2 (MIP-2), and platelet-activating factor (PAF) elicited by Ang-II, SB only reduced the release of MIP-2 after 4 h of its administration. Sixty-minute superfusion of the rat mesentery with 1 nM Ang-II induced a significant increase in the leukocyte-endothelial cell interactions and P-selectin up-regulation, which were inhibited by 1 microM BM and SB. The generation of reactive oxygen species (ROS) in endothelial cells stimulated with Ang-II was inhibited significantly by the three alkaloids tested. BM also diminished Ang-II-induced interleukin-8 release from endothelial cells and blocked the PAF receptor on human neutrophils (concentration of the compound needed to produce 50% inhibition value: 28.2 microM). Therefore, BM is a potent inhibitor of Ang-II-induced neutrophil accumulation in vivo. This effect appears to be mediated through inhibition of CXC chemokine and PAF release, ROS scavenging activity, and blockade of the PAF receptor. Thus, it may have potential therapeutic interest for the control of neutrophil recruitment that occurs in inflammation associated with elevated levels of Ang-II.

CD4+ T cell epitope affinity to MHC II influences the magnitude of CTL responses elicited by DNA epitope vaccines

Immunization with naked plasmid DNA elicits strong cell-mediated immune responses. In the present study, we examine strategies to enhance epitope-specific cytotoxic T lymphocyte (CTL) responses using DNA constructs, expressing a minimal class I epitope of the gp120 of HIV-IIIB. Here, we evaluate the effect of CD4+ T cell (T(H)) epitope affinity for the MHC II molecule on the immunogenicity of our DNA vaccines. Our data indicate that a low-affinity T(H) epitope decreased the magnitude of the CTL responses. In addition, we observed decreased numbers of epitope-specific T helper cells and CTLs, as well as diminished cytokine secretion and proliferative responses. Thus, the immunogenicity of a DNA epitope vaccine can be modulated by altering the affinity of the T(H) epitope.

Genes modulated by expression of GD3 synthase in Chinese hamster ovary cells. Evidence that the Tis21 gene is involved in the induction of GD3 9-O-acetylation

9-O-Acetylation is a common sialic acid modification, expressed in a developmentally regulated and tissue/cell type-specific manner. The relevant 9-O-acetyltransferase(s) have not been isolated or cloned; nor have mechanisms for their regulation been elucidated. We previously showed that transfection of the GD3 synthase (ST8Sia-I) gene into Chinese hamster ovary (CHO)-K1 cells gave expression of not only the disialoganglioside GD3 but also 9-O-acetyl-GD3. We now use differential display PCR between wild type CHO-K1 cells and clones stably expressing GD3 synthase (CHO-GD3 cells) to detect any increased expression of other genes and explore the possible induction of a 9-O-acetyltransferase. The four CHO mRNAs showing major up-regulation were homologous to VCAM-1, Tis21, the KC-protein-like protein, and a functionally unknown type II transmembrane protein. A moderate increase in expression of the FxC1 and SPR-1 genes was also seen. Interestingly, these are different from genes observed by others to be up-regulated after transfection of GD3 synthase into a neuroblastoma cell line. We also isolated a CHO-GD3 mutant lacking 9-O-acetyl-GD3 following chemical mutagenesis (CHO-GD3-OAc(-)). Analysis of the above differential display PCR-derived genes in these cells showed that expression of Tis21 was selectively reduced. Transfection of a mouse Tis21 cDNA into the CHO-GD3-OAc(-) mutant cells restored 9-O-acetyl-GD3 expression. Since the only major gangliosides expressed by CHO-GD3 cells are GD3 and 9-O-acetyl-GD3 (in addition to GM3, the predominant ganglioside type in wild-type CHO-K1 cells), we conclude that GD3 enhances its own 9-O-acetylation via induction of Tis21. This is the first known nuclear inducible factor for 9-O-acetylation and also the first proof that 9-O-acetylation can be directly regulated by GD3 synthase. Finally, transfection of CHO-GD3-OAc(-) mutant cells with ST6Gal-I induced 9-O-acetylation specifically on sialylated N-glycans, in a manner similar to wild-type cells. This indicates separate machineries for 9-O-acetylation on alpha2-8-linked sialic acids of gangliosides and on alpha2-6-linked sialic acids on N-glycans.

Upregulation of chemokine receptor gene expression in brains of Borna disease virus (BDV)-infected rats in the absence and presence of inflammation

Infection of adult rats with Borna disease virus (BDV) causes CD8 T cell-mediated meningoencephalitis. Previously, we described a complex pattern of chemokine gene expression in the central nervous system (CNS) of such rats. We now found that expression of chemokine receptor genes CXCR3, CCR5, CX(3)CR1, and CXCR4 was also upregulated, which is in agreement with the predominance in brains of adult infected rats of T cells and monocytes/macrophages that express these receptors. In contrast to these rats, neonatally infected rats (designated PTI-NB) develop a persistent CNS infection associated with neurodegenerative processes in the absence of inflammation. In brains of PTI-NB rats, sustained expression of chemokines also takes place. We therefore analyzed mRNA expression of selected chemokine receptor genes, as well as of the chemokine fractalkine in brains of PTI-NB rats. We observed a marked increase of CCR5 and CX(3)CR1 transcripts in brains of these rats. CX(3)CR1 expressing cells were predominantly microglia, and upregulation of CX(3)CR1 was mainly due to an increase in the number of CX(3)CR1 expressing microglia. Fractalkine gene expression was found to be reduced to similar extents in brains of adult and newborn infected rats. These findings might be of relevance with respect to the selective neuronal cell loss observed in brains of PTI-NB rats.

Anti-Fas induces hepatic chemokines and promotes inflammation by an NF-kappa B-independent, caspase-3-dependent pathway

Agonistic antibodies against the Fas receptor, when administered to mice in vivo, cause significant apoptosis in the liver. In this study we show that anti-Fas antibody not only causes apoptosis of liver cells but also provokes hepatic inflammation. Two hours after injection of anti-Fas, when mice displayed evidence of caspase-3 activation and apoptosis, we found significant hepatic induction of the CXC chemokines macrophage inflammatory protein-2 and KC. Coincident with the chemokine induction was infiltration of the hepatic parenchyma by neutrophils. Neutralization experiments identified that chemokines were the cause of Fas-induced hepatic inflammation, with KC having the predominant effect. Chemokine induction in the livers of anti-Fas-treated mice was not associated with activation of NF-kappa B. Instead, it coincided with nuclear translocation of activator protein-1 (AP-1). AP-1 activation in liver was detected 1-2 h after anti-Fas treatment, suggesting a connection to the onset of apoptosis. When apoptosis was prevented by pretreating mice with a caspase-3 inhibitor, AP-1 activation and hepatic chemokine production were both significantly reduced. Hepatic inflammation was also reduced by 70%. Taken together, these findings indicate that Fas ligation can induce inflammation in the liver in vivo. Inflammation does not arise from Fas-mediated signaling through NF-kappa B; rather, it represents an indirect effect, requiring activation of caspase-3 and nuclear translocation of AP-1.

Effects of neutrophil elastase inhibitor (ONO-5046) on lung injury after intestinal ischemia-reperfusion

The underlying mechanisms of lung endothelial injury after intestinal ischemia-reperfusion (I/R) injury are not fully known. Here we investigated the effects of posttreatment with a neutrophil elastase inhibitor (NEI; ONO-5046) on lung injury after intestinal I/R injury in a rat model. Intestinal I/R was produced by 90 min of ischemia followed by either 60 or 240 min of reperfusion. For all experimental groups, the endothelial permeability index increased, neutrophil H(2)O(2) production increased in the pulmonary vasculature blood, neutrophil counts increased in bronchoalveolar lavage fluid (BALF), and the cytokine-induced neutrophil chemoattractant (CINC)-1 and CINC-3 levels were increased in BALF after 240 min (P < 0.01). In rats treated with NEI from 60 min after reperfusion, the lung endothelial permeability index was significantly reduced (P < 0.05), whereas neutrophil H(2)O(2) production in pulmonary vasculature blood and neutrophil count in BALF were significantly suppressed by NEI (P < 0.05 and P < 0.01, respectively). In addition, NEI significantly suppressed the increase of CINC-1 and CINC-3 levels in BALF (P < 0.05). Our study clearly indicates that posttreatment with NEI reduces neutrophil activation in the pulmonary vessels and neutrophil accumulation in the lungs and suggests that ONO-5046, even when administered after the primary intestinal insult, can prevent the progression of lung injury associated with intestinal I/R.

Angiotensin AT1 receptor antagonist irbesartan decreases lesion size, chemokine expression, and macrophage accumulation in apolipoprotein E-deficient mice

Recent data suggest that angiotensin II AT1 receptor antagonists may be beneficial in the treatment of atherosclerosis. To clarify how AT1 receptor antagonists reduce atherosclerosis, the effect of irbesartan on atherosclerotic lesion development was determined in low-fat, chow-fed apolipoprotein (Apo) E-deficient mice. Irbesartan (50 mg/kg per day) strongly decreased lesion development after a 12-week treatment period (lesion size: irbesartan treated, 20,524 +/- 4,200 microm(2) vs. control, 99,600 +/- 14,500; 79.4% inhibition, p < 0.001). This effect was not due to an effect of irbesartan on lipoprotein levels because irbesartan slightly increased total cholesterol levels and decreased the ratio of Apo A-I relative to Apo B levels. Immunochemical analysis of the atherosclerotic lesions using the mac3 monoclonal antibody showed the presence of macrophages in the lesions of control mice, whereas sections from irbesartan-treated animals only showed occasional labeling in the lesion area. These data suggest that irbesartan inhibits monocyte/macrophage influx into the vessel wall. Therefore, expression levels of monocyte chemoattractant protein-1 (MCP-1), as well as other chemokines involved in macrophage infiltration into the lesion area, were measured in the aortic sinus of control and irbesartan-treated animals. Irbesartan treatment strongly decreased MCP-1 mRNA levels as well as MCP-1 immunostaining in the lesion area. This effect of irbesartan on MCP-1 occurred without an effect on CCR2, the receptor of MCP-1. Expression of macrophage inflammatory protein (MIP)-1alpha, another CC chemokine expressed in atherosclerotic lesions, was also reduced after irbesartan treatment, without effect on CCR3 and CCR5, the receptors of MIP-1alpha. Concomitantly, the expression of the angiogenic chemokines KC and MIP-2, which are functionally related to interleukin-8, were downregulated, whereas their shared receptor CXCR2 was upregulated. These data suggest that inhibition of the inflammatory component of lesion progression plays an important role in the inhibitory effect of AT1 receptor antagonists on atherosclerotic lesion formation.

Bile duct ligation in rats induces biliary expression of cytokine-induced neutrophil chemoattractant

BACKGROUND & AIMS

Bile duct obstruction causes neutrophilic inflammation of the liver and leads to hepatic fibrosis. In obstructive liver disease, the localization of neutrophils in portal tracts suggests that cells within this region produce neutrophil chemoattractants. In this study, we investigated whether bile duct obstruction in rats induces portal expression of cytokine-induced neutrophil chemoattractant (CINC).

METHODS

Rats underwent bile duct ligation for 3 hours to 8 days. CINC regulation was examined in vivo at various intervals by immunohistochemistry, ribonuclease protection, and in situ hybridization. CINC production was also investigated in cell culture, in response to putative stimuli from obstructed liver.

RESULTS

Bile duct ligation caused neutrophilic infiltration of the liver within 3 hours. CINC was also rapidly induced, with specific expression identified in biliary cells. Rat intrahepatic biliary cells produced CINC constitutively in culture; when exposed to cholestatic bile, they showed a 12-fold increase in CINC secretion. The effect of bile was not attributable to toxicity or to dissolved cytokines or endotoxin. Mechanical strain, designed to mimic the stretching of biliary cells during obstruction, did not induce CINC.

CONCLUSIONS

Biliary cells contribute to hepatic inflammation during cholestasis by producing neutrophil chemoattractants. A major stimulus to biliary chemoattractant production in vivo may be bile itself.

Inhibition of NF-kappaB activation by pyrrolidine dithiocarbamate prevents In vivo expression of proinflammatory genes

Background-The inability to inhibit multiple mediators of septic shock represents a major hurdle in the treatment of septic shock. In vivo inhibition of nuclear factor (NF)-kappaB activation, a transcription factor regulating expression of many proinflammatory genes, could provide a useful strategy for the treatment of septic shock. Methods and Results-In rats challenged with lipopolysaccharide (LPS) 8 mg/kg IV, we determined the time course of NF-kappaB activation and expression of multiple inflammatory signals: tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase-2 (COX-2), cytokine-inducible neutrophil chemoattractant (CINC), and intercellular adhesion molecule-1 (ICAM)-1. We studied the effects of in vivo inhibition of NF-kappaB activation using pyrrolidine dithiocarbamate (PDTC) on the expression of these mediators. NF-kappaB activation preceded the induction of TNF-alpha, COX-2, CINC, and ICAM-1 mRNAs. PDTC prevented the LPS-induced NF-kappaB activation but did not inhibit activation of the transcription factors AP-1, Sp-1, and CREB. PDTC inhibited the LPS-induced expression of TNF-alpha, COX-2, CINC, and ICAM-1 mRNA and proteins and reduced the LPS-induced increases in plasma TNF-alpha, 6-keto-prostaglandin F(1alpha), and CINC concentrations. Inhibition of expression of these mediators prevented the increases in myeloperoxidase activity (a measure of neutrophil sequestration) in the heart, lungs, and liver. Conclusions-NF-kappaB activation correlates with LPS-induced expression of TNF-alpha, COX-2, CINC, and ICAM-1 genes in vivo. PDTC inhibits NF-kappaB activation and expression of these proinflammatory genes and their products. Thus, blocking NF-kappaB activation may be an effective strategy in the treatment of septic shock.

Neutrophil chemokine production in the skin following scald injury

The present study was conducted to determine whether local production of neutrophil chemoattractant cytokines preceded the influx of neutrophils following dermal scald injury. To accomplish this, dermal tissue was examined for inflammatory infiltrate and the level of KC, a murine homolog of human interleukin-8, at various time points after scald injury. The studies reveal that there was a largely neutrophilic infiltrate at 1 day post-injury which persisted for 4 days. Dermal KC levels increased significantly at 4 h, returned to baseline at 8 h and were elevated again from 1 to 3 days post-burn (P < 0.01). At 3 days post-burn, KC was elevated 15-fold above the level in sham treated mice (P < 0.01). These observations demonstrate that the influx of neutrophils into the skin follows the expression of KC in the skin. This suggests that it should be possible to alter neutrophil accumulation at the wound site by manipulating the local chemokine signal.

Mediating phosphorylation events in the vanadium-induced respiratory burst of alveolar macrophages

Occupational exposure by inhalation to vanadium-containing particles such as residual oil fly ash results in respiratory tract inflammation. This inflammation, characterized by abundant neutrophilia, appears to be initiated by alveolar macrophages (AMs) encountering particles and the subsequent release of proinflammatory cytokines. Intracellular signaling events in these cells in response to particles or their components are largely unknown. We investigated two immediate responses of AMs to vanadium exposure in vitro, the production of reactive oxygen intermediates (ROI) or respiratory burst (RB), and the tyrosine phosphorylation of cellular proteins. Macrophages exposed in vitro to 100 microM vanadyl chloride/1 microCi 48V incorporated 8.3% of the metal after 30 min. Exposure of AMs to increasing concentrations of sodium metavanadate resulted in a dose-dependent increase in production of ROI as measured by dichlorofluorescin oxidation. The lowest dose yielding a significant response was 50 microM, whereas 1000 microM increased RB activity by 173%. NADPH oxidase inhibitors deoxy-D-glucose (100 mM) and diphenylene iodonium (25 microM) reduced the metavanadate-induced RB by 62 and 71%, respectively, implicating NADPH oxidase as the primary cellular source of ROI. Enhanced cerium chloride oxidation in response to metavanadate localized to the plasma membrane consistent with increased NADPH oxidase activity. Pretreatment of AMs with the epidermal growth factor receptor inhibitor, tryphostin B50 (10 microM), reduced the metavanadate-induced RB, but did not influence overall tyrosine phosphorylation. Metavanadate and H2O2 exposure greatly increased overall tyrosine phosphorylation, yielding a similar but distinguishable pattern of phosphorylation in these cells. These observations demonstrate that in vitro metavanadate exposure regulates two distinct, yet related intracellular signaling pathways important in initiating inflammatory responses in these cells: (1) activation of the NADPH oxidase complex with subsequent increased ROI synthesis, and (2) enhanced tyrosine phosphorylation of cellular proteins.

Selective glutathione depletion of mitochondria by ethanol sensitizes hepatocytes to tumor necrosis factor

BACKGROUND & AIMS

Tumor necrosis factor (TNF)-alpha induces cell injury by generating oxidative stress from mitochondria. The purpose of this study was to determine the effect of ethanol on the sensitization of hepatocytes to TNF-alpha.

METHODS

Cultured hepatocytes from ethanol-fed (ethanol hepatocytes) or pair-fed (control hepatocytes) rats were exposed to TNF-alpha, and the extent of oxidative stress, gene expression, and viability were evaluated.

RESULTS

Ethanol hepatocytes, which develop a selective deficiency of mitochondrial glutathione (mGSH), showed marked susceptibility to TNF-alpha. The susceptibility to TNF-alpha, manifested as necrosis rather than apoptosis, was accompanied by a progressive increase in hydrogen peroxide that correlated inversely with cell survival. Nuclear factor kappaB activation by TNF-alpha was significantly greater in ethanol hepatocytes than in control hepatocytes, an effect paralleled by the expression of cytokine-induced neutrophil chemoattractant. Similar sensitization of normal hepatocytes to TNF-alpha was obtained by depleting the mitochondrial pool of GSH with 3-hydroxyl-4-pentenoate. Restoration of mGSH by S-adenosyl-L-methionine or by GSH-ethyl ester prevented the increased susceptibility of ethanol hepatocytes to TNF-alpha.

CONCLUSIONS

These results indicate that mGSH controls the fate of hepatocytes in response to TNF-alpha. Its depletion caused by alcohol consumption amplifies the power of TNF-alpha to generate reactive oxygen species, compromising mitochondrial and cellular functions that culminate in cell death.

Rat hepatic stellate cells produce cytokine-induced neutrophil chemoattractant in culture and in vivo

Hepatic stellate cells are widely recognized for their contribution to liver fibrosis. This study investigated whether these cells also promote hepatic inflammation by producing neutrophil chemoattractants. Specifically, stellate cells were examined as potential sources of cytokine-induced neutrophil chemoattractant (CINC), a rat chemokine resembling human interleukin-8. Stellate cells from normal rat liver expressed little or no CINC. In culture, CINC mRNA was induced rapidly, coinciding with the phenomenon of culture activation. CINC mRNA rose 4.6-fold within 3 days and was accompanied by secretion of immunoreactive and biologically active CINC protein (4.1 ng . microgram DNA-1 . day-1). Studies in vivo demonstrated that CINC could be induced in stellate cells during liver injury. CINC mRNA rose significantly (4- to 6-fold) in two models of liver disease, both of which cause stellate cell activation. In summary, the data indicate that CINC is induced during stellate cell activation in culture and in vivo. They suggest that stellate cell-derived CINC can promote hepatic inflammation in vivo.

The role of NF-kappaB in retinal neovascularization in the rat. Possible involvement of cytokine-induced neutrophil chemoattractant (CINC), a member of the interleukin-8 family

Hypoxia precedes neovascularization in many retinal diseases that can lead to irreversible vision loss. The transcription factor NF-kappaB is activated by hypoxia and regulates the expression of many genes, including angiogenic factors. The relation between the NF-kappaB activation and the cytokine-induced neutrophil chemoattractant (CINC), a member of the interleukin-8 (IL-8) family, was investigated by immunohistochemistry in a rat model of proliferative retinopathy presumably caused by relative hypoxia. Activated NF-kappaB and CINC immunoreactivity was detected in retinal glial cells in the nonperfused retina and in neovascular cells. Activated NF-kappaB was detected before the CINC staining, and both of these events occurred before the development of neovascularization. The intensity of both activated NF-kappaB and CINC staining remained increased during the development of neovascularization and then declined as neovascularization regressed. In rat retinal glial cells in vitro, dexamethasone, an inhibitor of NF-kappaB activation, prevented the hypoxia-induced increase in the amount of CINC mRNA. Furthermore, CINC induced neovascularization in a rat corneal pocket model. These results suggest that hypoxia-induced activation of NF-kappaB results in CINC production and participates in the induction of retinal neovascularization.

Functional characterization of recombinant rat macrophage inflammatory protein-1 alpha and mRNA expression in pulmonary inflammation

Chemokines are important inflammatory mediators that function by activating and recruiting leukocytes to an inflamed tissue. We have recently cDNA cloned the rat chemokine macrophage inflammatory protein-1 alpha (MIP-1 alpha) (1). In the present study, we characterize the biological function of recombinant MIP-1 alpha protein and describe expression of its mRNA both in vitro and in a rat model of lung inflammation. In vitro rat rMIP-1 alpha protein was chemotactic for both polymorphonuclear leukocytes (PMNs) and macrophages with maximal activity at 50 nM for both cell types. In in vivo studies, we found that intratracheal instillation of 1 and 5 micrograms of rMIP-1 alpha resulted in a significant (P < 0.05) influx of cells, primarily monocytes/macrophages, into the airspace of the lungs after 6 h. Mean numbers of lavagable PMNs were not elevated significantly (P < 0.05) for either dose of MIP-1 alpha. As a model of inflammation, rats were intratracheally instilled with 0.1 mg/kg bacterial lipopolysaccharide (LPS). Bronchoalveolar lavage (BAL) was performed 3 h later. Instillation of LPS resulted in an acute neutrophilia, but no significant change in lavagable macrophages. BAL cells from control animals (saline instilled) displayed no basal mRNA expression of either MIP-1 alpha or MIP-2 (positive control). In contrast, both MIP-1 alpha and MIP-2 mRNA levels increased markedly in BAL cells from rats instilled with LPS. The rat alveolar macrophage cell line (NR8383) also showed increased MIP-1 alpha mRNA levels in response to LPS (10 micrograms/ml) with a maximal increase after 6-8 h. The induction of MIP-1 alpha mRNA expression by LPS in NR8383 cells was attenuated by cotreatment with the antioxidants N-acetylcysteine and dimethylsulfoxide, suggesting that the induction of MIP-1 alpha mRNA by LPS is mediated via the generation of reactive oxygen species. We conclude that MIP-1 alpha is a potent chemoattractant for macrophages in vivo, and its mRNA expression in macrophages and BAL cells in response to inflammatory stimuli suggests a fundamental role in acute pulmonary inflammation.

Influence of acetaminophen treatment and hydrogen peroxide treatment on the release of a CINC-related protein and TNF-alpha from rat hepatocyte cultures

Western blot analysis of conditioned media from hepatocytes exposed to H2O2 revealed that a 28 kDa protein was released dose-dependently in response to 1-10 mM H2O2. The 28 kDa protein was present in freshly isolated hepatocytes and exhibited cross-reactivity towards an antibody against CINC/gro. The intracellular amount of the protein decreased in parallel to the H2O2-induced release into the medium. The CINC-related protein was absent in media harvested after 1 h of treatment. The delivery of CINC-related protein correlated with the extent of cell damage as judged from lactate dehydrogenase leakage. Likewise, exposure of hepatocytes to 10-50 mM acetaminophen resulted in a dose-dependent release of the CINC-related protein after 24 h of culture. In contrast, monomeric CINC (molecular weight approximately 6.5 kDa) but not the 28 kDa CINC-related protein was released by lipopolysaccharide (LPS)-stimulated Kupffer cells. The amount of monomeric CINC liberated by Kupffer cells was diminished upon acetaminophen-treatment. Also, the release of tumor necrosis factor-alpha by hepatocytes was reduced after exposure to high acetaminophen doses (40-50 mM). In contrast to this finding, TNF-alpha release from hepatocyte cultures was not affected after H2O2 treatment. These data suggest that damaged hepatocytes release proinflammatory cytokines which may aggravate liver injury through activation of neutrophils and monocytes. The results indicate that the appearance of the CINC-related protein is due to impairment of plasma membrane integrity as the consequence of massive cell damage. In addition, APAP inhibited the release of monomeric CINC from LPS-activated Kupffer cells and of TNF-alpha from hepatocytes even at concentrations that were not sufficient to affect cell viability.

Human T-cell lymphotropic virus type 1 can infect primary rat retinal glial cells and induce gene expression of inflammatory cytokines

PURPOSE

To examine whether or not retinal glial cells can be infected by human T-cell lymphotropic virus type 1 (HTLV-1) and test the possibility that HTLV-1-infected retinal glial cells are involved in the pathogenesis of HTLV-1 uveitis (HU).

METHODS

We tested infection of HTLV-1 by a standard coculturing method using WKAH rat retinal glial cells and irradiated MT-2, a human T cell line that produces HTLV-1. Infection was confirmed by detecting the integrated HTLV-1 provirus, using polymerase chain reaction (PCR), viral gene expression, using reverse transcriptase-PCR (RT-PCR) and HTLV-1 p19 ELISA, and by identifying the HTLV-1-infected glial cells by immunofluorescence cytochemistry and in situ hybridization. Changes in cytokine gene expression were studied by RT-PCR.

RESULTS

Using a semiquantitative PCR of HTLV-1 provirus sequence, we found that 2.6% of the retinal glial cells were infected at 3 days after infection, followed by a gradual decrease in the percentage with an extended period of culture up to 4 weeks. This time course of infection was also verified by RT-PCR and ELISA studies that detect viral mRNA expression and protein production, respectively. Expression of HTLV-1 gag protein and tax mRNA was detected in a part of glial cells by indirect immunofluorescence cytochemistry and in situ hybridization, respectively. RT-PCR analysis of cytokine gene expression revealed that gene expression of IL-6, CINC-1 (Gro, KC), and TNF-alpha were induced in these cells, with a peak at 3 weeks after infection.

CONCLUSION

These results provided supportive evidence for the theory that the infection of retinal glial cells by HTLV-1 and subsequent production of inflammatory cytokines could be one contributing factor for the development of the unique clinical features of HU. A better understanding of the specific roles of the inflammatory cytokines in the pathogenesis of HU would be beneficial in the treatment and control of this disease.

The pulmonary inflammatory response to experimental fecal peritonitis: relative roles of tumor necrosis factor-alpha and endotoxin

The roles of endotoxin (LPS) and tumor necrosis factor-alpha (TNF-alpha) in the causation of organ injury during sepsis are unclear. To study LPS and TNF-alpha in the genesis of lung inflammation after cecal ligation and puncture (CLP), we used endotoxin-resistant (C3H/HeJ) and endotoxin-sensitive mice (C3H/HeOuJ). We examined lung neutrophil sequestration, interleukin 1 (IL-1)beta mRNA expression, IL-1 beta protein expression, and injury. We also determined the expression of two C-X-C chemokine mRNAs, macrophage inflammatory protein-2 (MIP-2) and KC, in the lung to determine whether in vivo, endotoxin, or TNF-alpha are significant modulators of MIP-2 and KC mRNA expression. After CLP, increased neutrophils sequestrated in the lungs of both strains of mice and coincided with an increase in expression of IL-1 beta, MIP-2 and KC mRNAs, and IL-1 beta protein. Lung and serum TNF-alpha were significantly increased in the C3H/HeOuJ strain but not in the C3H/HeJ strain. Histologic studies of the lung revealed similar injury in both strains. Our results suggest that bacterial factors other than endotoxin cause lung neutrophil sequestration and injury after CLP and, further, that TNF-alpha production is not a prerequisite. Our findings also suggest a potential role for local pulmonary chemokine production in the control of neutrophil sequestration after CLP.

Interleukin-1 stimulates rapid release of cytokine-induced neutrophil chemoattractant (CINC) in rat lungs

We found that intratracheal insufflation of interleukin-1 alpha (IL-1) in rats rapidly increased lung lavage cytokine-induced neutrophil chemoattractant (CINC) concentrations, lung tissue myeloperoxidase (MPO) activity, and lung lavage neutrophil counts, and that CINC elevation preceded the migration of neutrophils into the lung. Further, we found that bolus CINC insufflation increased CINC concentrations in plasma, and we found that alveolar macrophages (AM) in lung tissue selections or AM recovered by lavage from rats given IL-1 intratracheally stained positively for CINC by immunohistochemistry. In addition, incubating rat AM with increasing doses of IL-1 in vitro progressively increased CINC concentrations in the culture medium. Our results suggest that the potent neutrophil chemoattractant CINC is rapidly produced and released by rat AM following challenge with IL-1 in vivo or in vitro, and support the hypothesis that CINC is an important mediator in the development of pulmonary inflammation in the rat.

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.

Molecular expression of the alpha-chemokine rabbit GRO in Escherichia coli and characterization of its production by lung cells in vitro and in vivo

GRO proteins are alpha-chemokine cytokines that attract neutrophils and stimulate the growth of a variety of cells. Previously, we observed that rabbit alveolar macrophages transcribe the genes for at least two GRO homologues. In order to study the role of GRO cytokines in lung inflammation, we cloned the predominant rabbit GRO cDNA (RabGRO) from alveolar macrophages, expressed bioactive recombinant protein (rRabGRO) in Escherichia coli, and developed a sensitive and specific enzyme-linked immunosorbent assay for RabGRO protein. We found that rabbit AM express and secrete GRO in vitro in response to both exogenous (e.g. lipopolysaccharide, heat-killed Staphylococcus aureus, and crystalline silica) and endogenous inflammatory stimuli (e.g. tumor necrosis factor-alpha) as determined by both radioimmunoprecipitation and enzyme-linked immunosorbent assay. Biologically significant amounts of GRO are present in vivo in the bronchoalveolar lavage fluid of rabbits with E. coli pneumonia; by in situ hybridization, GRO mRNA is detectable in infiltrating pulmonary leukocytes and bronchial epithelial cells. These results indicate that GRO chemokines are likely to be important mediators of the inflammatory response that accompanies acute infectious processes in the lungs.

Regulation of macrophage inflammatory protein-1alpha mRNA by oxidative stress

Accumulation of inflammatory cells within the lung has been implicated in oxidative injury. Recruitment of these cells to a tissue site is a complex process that depends in part upon the local expression of appropriate proinflammatory chemokines. Macrophage inflammatory protein-1alpha (MIP-1alpha), a member of the CC subfamily of chemokines, has been shown to contribute to monocyte/macrophage and neutrophil chemotaxis and activation. Our previous work demonstrated that MIP-1alpha mRNA expression in macrophages is induced by bacterial endotoxin. The objective of this study was to test the hypothesis that an oxidative stress alone may trigger expression of MIP-1alpha mRNA in macrophages and to determine the mechanism leading to increased expression. A rat alveolar macrophage cell line (NR8383) was exposed to H2O2 or menadione (2-methyl-1,4-naphthoquinone (MQ)), a quinone compound that undergoes redox cycling and generates reactive oxygen species continuously. Steady-state mRNA levels encoding MIP-1alpha were markedly increased (3-fold) in these cells after 1 h of exposure to 0.5 mM H2O2, remained higher than control levels after 4 h, and decreased after 6 h. Similarly, MQ (25 or 50 microM) caused a significant increase of MIP-1 alpha mRNA with a maximal induction after 4 h of exposure (5-fold). Both H2O2 and MQ-induced up-regulation of MIP-1 alpha mRNA was suppressed by co-treatment with N-acetylcysteine, a synthetic antioxidant. Co-treatment with actinomycin D reduced the MQ induction of MIP-1alpha mRNA to a greater extent than the H2O2-induced increase. Transcription of the MIP-1alpha gene was increased by exposure to both H2O2 and MQ. H2O2 treatment also induced a marked increase of the MIP-1alpha mRNA half-life, indicating post-transcriptional stabilization. These observations indicate that an oxidative stress can regulate MIP-1alpha mRNA expression by two distinct mechanisms: transcriptional activation of the MIP-1alpha gene and post-transcriptional stabilization of MIP-1alpha mRNA.

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.

Locally produced tumor necrosis factor-alpha mediates interleukin-2-induced lung injury

Interleukin (IL)-2-induced microvascular lung injury is an experimental paradigm commonly used to investigate the pathogenesis of the adult respiratory distress syndrome. Since tumor necrosis factor-alpha (TNF-alpha) is known to induce such an injury in vivo and since TNF-alpha is involved in other models of lung injury, we postulated that it might also mediate pulmonary toxicity after IL-2 administration. The present study tested this hypothesis by evaluating the effect of TNF-alpha inhibition on IL-2-induced lung injury in the rat. Recombinant human IL-2 (10(6) U IV per rat, n = 6) elevated lung water, myeloperoxidase activity, and protein accumulation in bronchoalveolar lavage fluid and induced tissue hypoxia. Also, IL-2 enhanced lung tissue TNF-alpha mRNA and peptide (1543 +/- 496 pg/g lung wet weight) localized to alveolar macrophages by in situ hybridization. In marked contrast, IL-2 failed to affect serum TNF-alpha, which remained at undetectable levels. Pretreatment with anti-TNF-alpha monoclonal antibody (25 mg/kg IV, n = 7) or the TNF-alpha synthesis inhibitor rolipram (200 micrograms/kg IV, n = 7) attenuated lung injury and reverted tissue hypoxia. Furthermore, TNF-alpha inhibition prevented the upregulation of lung tissue IL-1 beta, IL-6, cytokine-induced neutrophil chemoattractant, and E-selectin (ELAM-1) but not intercellular adhesion molecule-1 mRNAs in response to IL-2. These data imply that locally produced TNF-alpha mediates IL-2-induced lung inflammation and tissue injury and point to the potential utilization of TNF-alpha inhibitors in treating the pulmonary toxicity of IL-2 immunotherapy.

Reovirus infection in rat lungs as a model to study the pathogenesis of viral pneumonia

We undertook the present study to elucidate the pathogenesis of the pathologic response to reovirus infection in the lungs and further understand the interactions of reoviruses with pulmonary cells. We found that reoviruses were capable of causing acute pneumonia in 25- to 28-day-old Sprague-Dawley rats following intratracheal inoculation with the reoviruses type 1 Lang (T1L) and type 3 Dearing (T3D). The onset of the pneumonia was rapid, marked by type I alveolar epithelial cell degeneration, type II alveolar epithelial cell hyperplasia, and the infiltration of leukocytes into the alveolar spaces. More neutrophils were recruited into the lungs during T3D infection than during T1L infection, and the serotype difference in the neutrophil response was mapped to the S1 gene of reovirus. Viral replication in the lungs was required for the development of pneumonia due to T1L and T3D infections, and replication occurred in type I alveolar epithelial cells. T1L grew to higher titers in the lungs than did either T3D or type 3 clone 9, and the S1 gene was found to play a role in determining the level of viral replication. We propose that experimental reovirus infection in the lungs can serve as a model for the pathogenesis of viral pneumonia in which pulmonary inflammation results following direct infection of lung epithelial cells.

Cytokine-induced neutrophil chemoattractant production by primary rat alveolar type II cells

This study was designed to determine the production of the chemokine cytokine-induced neutrophil chemoattractant (CINC) by primary rat alveolar type II (ATII) cells upon stimulation with exogenous and endogenous proinflammatory factors. Cultures of primary rat ATII cells were exposed to lipopolysaccharide (LPS), interleukin-1 beta (IL-1 beta) or tumor necrosis factor-alpha (TNF alpha) over a 16 hour period and the production of CINC both apically and basolaterally was measured by ELISA. Compared to unstimulated (UNS) cultures, LPS, IL-1 beta and TNF alpha were found to significantly increase the level of CINC detected in culture by two, four and sixteen hours post stimulation, respectively. ATII cells also demonstrated a polar secretion of CINC. The accumulation of CINC basolaterally was significantly more than apically; 133%, 45%, 117% and 123% for UNS, IL-1 beta, LPS and TNF alpha respectively. We demonstrated that primary rat ATII cells may participate in the chemokine network during inflammation by the production of CINC upon stimulation with endogenous and exogenous factors.

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.

Regulation of cytokine-induced neutrophil chemoattractant (CINC) mRNA production in cultured rat cells

Rat cytokine-induced neutrophil chemoattractant (CINC) is an 8-kD polypeptide originally purified from media conditioned by interleukin-1 beta (IL-1 beta)-stimulated 52E, an epithelioid clone derived from the normal rat kidney (NRK) cell line. Using a fibroblastic clone of NRK cells, 49F, we found that lipopolysaccharide (LPS), IL-1 beta, and tumor necrosis factor-alpha (TNF-alpha) each induce synthesis of CINC mRNA and CINC, although in qualitatively and quantitatively different patterns. Through deadenylation experiments and by probing with oligonucleotides, we discovered that the smaller of the two major CINC transcripts appears to arise from the larger as a result of poly(A) tail removal and/or 3' cleavage.

Cytokine-induced neutrophil chemoattractant mRNA expressed in cerebral ischemia

Cytokine-induced neutrophil chemoattractant (CINC), originally identified as a chemoattractant in rat kidney epithelial cells, is related to human 'gro' and murine 'KC'. The proteins encoded by these genes belong to the chemokine alpha superfamily, most of which have neutrophil chemotactic activity. Since brain chemokines may play a significant role in neutrophil accumulation in cerebral ischemia which can contribute to the extent of tissue injury in stroke, we examined the expression of CINC mRNA in the cerebral cortex of rats subjected to focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO). Significant CINC mRNA expression was observed in the ipsilateral (ischemic) cortex from 6 h (17.3 +/- 3.7%, n = 6, P < 0.05) to 24 h (32.1 +/- 3.7%, n = 5, P < 0.01) with a peak at 12 h (43.9 +/- 3.7%, n = 6, P < 0.01) after MCAO. Five days post-MCAO, CINC mRNA levels were no longer elevated. No significant CINC mRNA expression was observed in the contralateral (control) cortex. These studies suggest that message for the neutrophil chemoattractant CINC is induced early in brain tissue subjected to ischemia, and therefore supports the possibility that brain-derived chemokines support the infiltration of circulating inflammatory cells following focal stroke.

Recombinant expression of rat and human Gro proteins in Escherichia coli

A full-length rat gro cDNA containing the signal sequence was inserted to a plasmid/phage vector pTD-lacs which had the Escherichia coli alkaline phosphatase leader sequence down-stream of the lac promoter. After removal of the gro signal sequence by site-directed mutagenesis, the vector was introduced to E. coli JM109. The cells grown in the presence of isopropyl beta-D-thiogalactopyranoside were found to contain the recombinant mature rat Gro protein in the periplasmic space. The protein was released from the cells by osmotic shock, and could be purified to homogeneity from the periplasmic fluid by a single-step procedure using reverse phase high performance liquid chromatography. By similar procedures, recombinant human Gro alpha could be obtained. In each case, about 10 mg of purified cytokine were obtained from 1 litre of bacterial culture.

Investigation of possible autocrine functions for rat GRO/CINC (cytokine-induced neutrophil chemoattractant)

Rat cytokine-induced neutrophil chemoattractant (CINC) is an eight kilodalton polypeptide originally purified from media conditioned by interleukin-1 beta stimulated 52E, an epithelioid clone derived from normal rat kidney (NRK) cells. Using a fibroblastic clone of the NRK cells, 49F, we found expression of the CINC gene to be induced by either serum or cytokines in growth-arrested cultures within 1 hour of stimulation. There was no observable CINC expression in exponentially growing cells in the absence of cytokine stimulation. CINC protein had no significant effect on 3H-thymidine incorporation or growth rate of NRK49F. We have observed that CINC is constitutively produced by some transformed NRK cells, clone RC20, suggesting an association with the expression of a transformed phenotype. Unlike the parent 49F, RC20 cells are capable of growth in soft agar and serum-free media and form highly metastatic tumors in nude mice. We have examined the possible autocrine functions of CINC and its possible links to the expression of the transformed phenotype by these cells. The use of a blocking CINC polyclonal antibody demonstrated that CINC did not function as an autocrine growth factor for RC20. Though CINC is a potent chemoattractant for neutrophils, it did not induce migration of either RC20 or 49F cells. CINC only moderately promoted adhesion of RC20 cells when used as a matrix protein. These data do not support the hypothesis that production of CINC by the RC20 cells provides an obvious advantage for the transformed cells constitutively producing it.

High-level expression of cytokine-induced neutrophil chemoattractant (CINC) by a metastatic rat cell line: purification and production of blocking antibodies

Significant levels of cytokine-induced neutrophil chemoattractant (CINC) were found in serum-free medium conditioned by a highly metastatic rat cell line, RC20. To study CINC's role in inflammation and metastasis, CINC was purified from this source for use in in vitro assays and for antibody production in goats and rabbits. CINC was a potent chemoattractant for rat neutrophils (EC-50 0.5 nM). A fusion protein of glutathione-S-transferase and CINC (GST-CINC) was produced in E. coli. Anti-CINC polyclonal IgG was purified from immune goat and rabbit sera by protein A and GST-CINC affinity chromatography. Both goat and rabbit anti-CINC antibody preparations at 4 micrograms/mL (an 11-fold molar excess) were found to completely block the activity of 2.5 nM CINC in a rat neutrophil chemotaxis assay. These antibodies have been used to develop a sensitive immunoassay for CINC. The availability of large amounts of affinity-purified blocking anti-CINC antibody will allow investigations into the role played by CINC in rodent inflammation models and in the metastasis of RC20 cells.

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

Potent chemotactic activity for neutrophils was detected in rat inflammatory exudate induced by a subcutaneous injection of lipopolysaccharide in a carboxymethyl-cellulose suspension. We purified and characterized chemoattractants from the exudate by the following procedures: carboxymethyl-Sephadex C-25 ion-exchange chromatography; G3000SW gel-filtration chromatography; preparative reverse-phase high-pressure liquid chromatography; rechromatography on reverse-phase HPLC. Two chemotactic factors were purified and their N-terminal amino acid sequences were determined. One factor was a protein in which the first 20 N-terminal amino acids were identical to those of rat cytokine-induced neutrophil chemoattractant (CINC), a counterpart of human gro/melanoma growth-stimulating activity (MGSA). The other factor was highly similar to mouse macrophage inflammatory protein 2 (MIP-2). Mouse MIP-2, a chemotactic factor for neutrophils, is a member of the interleukin-8 family; however the protein we purified had higher similarity to human gro/MGSA than to human interleukin-8. These results indicate that, in rats, chemotactic factors for neutrophils induced by lipopolysaccharide stimulation are not counterparts of interleukin-8, but are gro/CINC-related peptides.

Structure of the gene encoding rat neutrophil chemo-attractant Gro

A cloned rat gro gene encoding the neutrophil chemo-attractant Gro was isolated from a lambda Charon4A rat genomic library, and the nucleotide (nt) sequence of a 2500-bp fragment encompassing the coding region and 3'- and 5'-flanking regions was determined. The gene consisted of four exons separated by three introns. The transcription start point was determined by primer-extension analysis and found to be a G located 72 nt upstream from the start codon. The 5'-flanking region of the gene contained a 'TATA'-like structure and an NF-kappa B-binding sequence.