The role of tumor necrosis factor and interleukin 1 in the immunoinflammatory response

Proinflammatory cytokines levels in patients with temporomandibular joint disorder undergoing arthroscopy

PURPOSE

Biomarkers represent objective indicators of normal processes, pathology, or responses to therapeutic intervention. The purpose of this study is to evaluate the levels of proinflammatory cytokines in synovial fluid of the temporomandibular joint (TMJ) and to investigate whether there is a correlation between elevated levels and disease progression.

MATERIALS AND METHODS

This is a prospective study that included patients who were diagnosed with internal derangement according to magnetic resonance imaging and were classified according to Wilkes's classifications. After failing to improve with conservative treatment, they were referred for TMJ arthroscopy. During arthroscopy, synovial fluid was collected for biomarker analyses that included the investigation of levels of proinflammatory cytokines: tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and vascular endothelial growth factor (VEGF). The Mann-Whitney U test was used for differences between subgroups for TNF-α, IL-6, and VEGF.

RESULTS

During the study period, 22 patients presented with a TMJ disorder and met the criteria of the study. There was a statistically significant correlation between the levels of VEGF, TNF-a, and osteoarthritis (P < 0.05). There was also a statistically significant correlation between TNF-a levels and a higher degree of chondromalacia (P = 0.019).

CONCLUSION

An increase in inflammatory cytokines coupled with chondromalacia propose a more aggressive degenerative disease.

Anti-Inflammatory Activity of Diterpenoids from Celastrus orbiculatus in Lipopolysaccharide-Stimulated RAW264.7 Cells

Celastrus orbiculatus Thunb has been known as an ethnopharmacological medicinal plant for antitumor, anti-inflammatory, and analgesic effects. Although various pharmacological studies of C. orbiculatus extract has been reported, an anti-inflammatory mechanism study of their phytochemical constituents has not been fully elucidated. In this study, compounds 1-17, including undescribed podocarpane-type trinorditerpenoid (3), were purified from C. orbiculatus and their chemical structure were determined by high-resolution electrospray ionization mass (HRESIMS) and nuclear magnetic resonance (NMR) spectroscopic data. To investigate the anti-inflammatory activity of compounds 1-17, nitric oxide (NO) secretion was evaluated in LPS-treated murine macrophages, RAW264.7 cells. Among compounds 1-17, deoxynimbidiol (1) and new trinorditerpenoid (3) showed the most potent inhibitory effects (IC₅₀: 4.9 and 12.6 μM, respectively) on lipopolysaccharide- (LPS-) stimulated NO releases as well as proinflammatory mediators, such as inducible nitric oxide (iNOS), cyclooxygenase- (COX-) 2, interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α. Its inhibitory activity of proinflammatory mediators is contributed by suppressing the activation of nuclear transcription factor- (NF-) κB and mitogen-activated protein kinase (MAPK) signaling cascades including p65, inhibition of NF-κB (IκB), extracellular signal-regulated kinase (ERK), c-Jun NH₂-terminal kinase (JNK), and p38. Therefore, these results demonstrated that diterpenoids 1 and 3 obtained from C. orbiculatus may be considered a potential candidate for the treatment of inflammatory diseases.

Blocking of gastric acid induced histopathological alterations, enhancing of DNA content and proliferation of goblet cells in the acute lung injury mice models by nano-fenugreek oral administration

This current study aimed at detecting the potential protective role of nano-fenugreek seed on acute lung injury (ALI) induced by instillation gastric acid in male Swiss albino mice using histological and histochemical studies. Forty animals were grouped as follows: control group, HCl-treated group, low nano-fenugreek + HCl treated group, and high nano-fenugreek + HCl treated group. Pretreatment with nano-fenugreek in animal model of ALI resulted in marked ameliorations of the lung histological lesions and injury induced by HCL instillation in a dose dependent manner. It also caused inhibition in the increase of the DNA content and prevented proliferation of goblet cells induced by HCl instillation alone. In conclusion, pretreatment with Nano-fenugreek prior induction ALI could be suppress the aggregations of inflammatory cells, enhancing of DNA content, and proliferation of goblet cells induced by gastric acid in a dose dependent manner. We suggest that Nano-fenugreek may be useful in combating lung injury.

Role of glutamine in the mediation of E-cadherin, p120-catenin and inflammation in ventilator-induced lung injury

Background:

Ventilator-induced lung injury (VILI) is commonly associated with barrier dysfunction and inflammation reaction. Glutamine could ameliorate VILI, but its role has not been fully elucidated. This study examined the relationship between inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α, and IL-10) and adherens junctions (E-cadherin, p120-catenin), which were ameliorated by glutamine in VILI, both in vitro and in vivo.

Methods:

For the in vivo study, 30 healthy C57BL/6 mice weighing 25–30 g were randomly divided into five groups with random number table (n = 6 in each group): control (Group C); low tidal volume (Group L); low tidal volume + glutamine (Group L + G); high tidal volume (Group H); and high tidal volume + glutamine (Group H + G). Mice in all groups, except Group C, underwent mechanical ventilation for 4 h. For the in vitro study, mouse lung epithelial 12 (MLE-12) cells pretreated with glutamine underwent cyclic stretching at 20% for 4 h. Cell lysate and lung tissue were obtained to detect the junction proteins, inflammatory cytokines, and lung pathological changes by the Western blotting, cytokine assay, hematoxylin and eosin staining, and immunofluorescence.

Results:

In vivo, compared with Group C, total cell counts (t = −28.182, P < 0.01), the percentage of neutrophils (t = −28.095, P < 0.01), IL-6 (t = −28.296, P < 0.01), and TNF-α (t = −19.812, P < 0.01) in bronchoalveolar lavage (BAL) fluid, lung injury scores (t = −6.708, P < 0.01), and the wet-to-dry ratio (t = −15.595, P < 0.01) were increased in Group H; IL-10 in BAL fluid (t = 9.093, P < 0.01) and the expression of E-cadherin (t = 10.044, P < 0.01) and p120-catenin (t = 13.218, P < 0.01) were decreased in Group H. Compared with Group H, total cell counts (t = 14.844, P < 0.01), the percentage of neutrophils (t = 18.077, P < 0.01), IL-6 (t = 18.007, P < 0.01), and TNF-α (t = 10.171, P < 0.01) in BAL fluid were decreased in Group H + G; IL-10 in BAL fluid (t = −7.531, P < 0.01) and the expression of E-cadherin (t = −14.814, P < 0.01) and p120-catenin (t = −9.114, P < 0.01) were increased in Group H + G. In vitro, compared with the nonstretching group, the levels of IL-6 (t = −21.111, P < 0.01) and TNF-α (t = −15.270, P < 0.01) were increased in the 20% cyclic stretching group; the levels of IL-10 (t = 5.450, P < 0.01) and the expression of E-cadherin (t = 17.736, P < 0.01) and p120-catenin (t = 16.136, P < 0.01) were decreased in the 20% cyclic stretching group. Compared with the stretching group, the levels of IL-6 (t = 11.818, P < 0.01) and TNF-α (t = 8.631, P < 0.01) decreased in the glutamine group; the levels of IL-10 (t = −3.203, P < 0.05) and the expression of E-cadherin (t = −13.567, P < 0.01) and p120-catenin (t = −10.013, P < 0.01) were increased in the glutamine group.

Conclusions:

High tidal volume mechanical ventilation and 20% cyclic stretching could cause VILI. Glutamine regulates VILI by improving cytokines and increasing the adherens junctions, protein E-cadherin and p120-catenin, to enhance the epithelial barrier function.

Inflammation, von Willebrand factor, and ADAMTS13

Increasing evidence indicates that inflammation can cause thrombosis by a von Willebrand factor (VWF)-mediated mechanism that includes endothelial activation, secretion of VWF, assembly of hyperadhesive VWF strings and fibers, cleavage by ADAMTS13, and adhesion and deposition of VWF-platelet thrombi in the vasculature. This mechanism appears to contribute to thrombosis not only in small vessels, but also in large vessels. Inflammation and VWF contribute to atherogenesis and may contribute to arterial and venous thrombosis as well as stroke. Elucidation of the mechanism will hopefully identify new targets and suggest new approaches for prevention and intervention.

The Effect of Platform Switching on Periimplant Crevicular Fluid Content During Early Wound Healing

PURPOSE

The objective of this study was to investigate the soft tissue response and periimplant crevicular fluid (PICF) content around platform-switched (PS) and platform-matched (PM) implants during early healing.

MATERIALS AND METHODS

Nonsmokers treatment planned to receive a single implant in 2 quadrants were recruited. Two-stage implant placement protocol with 1 PM and 1 PS implant was implemented. Periimplant probing depths (PDs), modified sulcus bleeding index, and plaque indices were recorded, and PICF was collected at 1, 2, 4, and 6 weeks after abutment connection.

RESULTS

PD readings were higher at week 1 than at week 6 for both groups (P = 0.0005). PD was statistically deeper in PM than in PS at week 1 (P = 0.03). There was a time-dependent decrease in total PICF volume for both groups. This decrease was statistically significant for PS (P = 0.0005), with no differences between the 2 groups at any time (P > 0.05). The decrease observed in both PM and PS for PICF interleukin 6 and macrophage inflammatory protein-1β, and in PS for tumor necrosis factor-α (TNF-α) was statistically significant (P ≤ 0.03). TNF-α was statistically higher in PS than in PM at week 1 (P = 0.005).

CONCLUSION

Within the limits of this study, it seems that periimplant soft tissue response around PM and PS implants is mostly similar during the early healing period.

Pulmonary Expression of Tumor Necrosis Factor Alpha, Interleukin-1 Beta, and Interleukin-8 in the Acute Phase of Bovine Pneumonic Pasteurellosis

Inflammatory cytokines are suspected to contribute to the pathogenesis of bovine pneumonic pasteurellosis (BPP) through neutrophil recruitment, leukocyte activation, and the induction of a broad array of soluble inflammatory mediators. An in vivo experimental model of BPP was used to characterize the pulmonary expression kinetics of tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β), and interleukin-8 (IL-8) genes and proteins during the acute phase of disease development. Cytokine expression in bronchoalveolar lavage (BAL) fluid, BAL cells, and pneumonic lung parenchyma was quantitated by northern blot analysis, enzyme-linked immunosorbent assay (ELISA), and in situ hybridization at 2, 4, 8, 16, and 24 hours after endobronchial inoculation of Pasteurella (Mannheimia) haemolytica. Expression of TNFα, IL-1β, and IL-8 was significantly increased in the airways and lung lesions of infected calves as compared with mock-infected controls. Although kinetic patterns varied, peak levels of cytokine mRNA occurred within 8 hours postinfection (PI), and peak cytokine concentrations occurred within 16 hours PI. In all samples, IL-8 was expressed to the greatest extent and TNFα was least expressed. Expression of TNFα was restricted to alveolar macrophages. Alveolar and interstitial macrophages produced IL-1β and IL-8 in the first 4 hours; bronchial and bronchiolar epithelial cells were also significant sources of IL-8 during this period. By 8 hours PI, neutrophils were the dominant source of both IL-1β and IL-8. These findings demonstrate a spatial and temporal association between pulmonary expression of inflammatory cytokines and acute lung pathology, supporting the hypothesis that cytokines contribute to inflammatory lung injury in BPP.

Higher TNFα responses in young males compared to females are associated with attenuation of monocyte adenylyl cyclase expression

Tumor necrosis factor α (TNFα) expression is strongly attenuated by the intracellular signaling mediator cyclic adenosine monophosphate (cAMP), which is synthesized by adenylyl cyclase (AC) enzymes. We have compared AC regulation and TNFα production in male and female monocytes, and characterized the role of monocyte AC isoforms in TNFα regulation. Males and females, age groups 20-30 years and 50-70 years donated blood for this study. In lipopolysaccharide-stimulated blood from young male donors, we observed significantly higher TNFα responses (6h, p=0.03) compared to females of the same age, a difference not observed in the older donors. Rapid down-regulation of the monocyte AC isoforms AC4, AC7 and AC9 were observed in young males. AC-directed siRNA experiments in the human monocyte cell line THP-1 demonstrated that AC7 and AC9 knock-down significantly induced TNFα release (p=0.01 for both isoforms). These data indicate that the stronger TNFα-responses in young males may be partly associated with male-specific down-regulation of adenylyl cyclases.

Tumor necrosis factor-alpha levels in the synovial fluid of patients with temporomandibular joint internal derangement

PURPOSE

The purpose of this study was to investigate the level of tumor necrosis factor-alpha (TNF-α) in the synovial fluid (SF) of patients with temporomandibular joint (TMJ) internal derangement and to show the relationship between the level of TNF-α and the severity of the disease.

MATERIALS AND METHODS

Arthrocentesis was performed on 32 female and five male patients (aged between 17 and 45) referred to our clinic with the complaint of TMJ pain and discomfort. TNF-α levels were determined in the SF samples obtained during arthrocentesis. As a measure of pain, visual analog scale (VAS) scores were also evaluated.

RESULTS

There were statistically significant differences in VAS scores between the stages. VAS scores were found to be elevated as the stage of disease progressed. Increased levels of TNF-α were found in progressive stages of internal derangement.

CONCLUSION

In our study, both SF TNF-α levels and pain levels (VAS scores) were found to be increased in patients with internal derangement as the stage of the disease progresses. TNF-α might contribute to the pathogenesis of synovitis and the degeneration of the TMJ cartilage and bone.

Glutamine attenuates acute lung injury caused by acid aspiration

Inadequate ventilator settings may cause overwhelming inflammatory responses associated with ventilator-induced lung injury (VILI) in patients with acute respiratory distress syndrome (ARDS). Here, we examined potential benefits of glutamine (GLN) on a two-hit model for VILI after acid aspiration-induced lung injury in rats. Rats were intratracheally challenged with hydrochloric acid as a first hit to induce lung inflammation, then randomly received intravenous GLN or lactated Ringer's solution (vehicle control) thirty min before different ventilator strategies. Rats were then randomized to receive mechanical ventilation as a second hit with a high tidal volume (TV) of 15 mL/kg and zero positive end-expiratory pressure (PEEP) or a low TV of 6 mL/kg with PEEP of 5 cm H2O. We evaluated lung oxygenation, inflammation, mechanics, and histology. After ventilator use for 4 h, high TV resulted in greater lung injury physiologic and biologic indices. Compared with vehicle treated rats, GLN administration attenuated lung injury, with improved oxygenation and static compliance, and decreased respiratory elastance, lung edema, extended lung destruction (lung injury scores and lung histology), neutrophil recruitment in the lung, and cytokine production. Thus, GLN administration improved the physiologic and biologic profiles of this experimental model of VILI based on the two-hit theory.

The impact of pretreatment with bolus dose of enteral glutamine on acute lung injury induced by oleic acid in rats

PURPOSE

Both parenteral and enteral glutamine have shown beneficial effects in sepsis and ischemia/reperfusion-induced acute lung injury (ALI). Oleic acid (OA) has been used to induce ALI in experimental studies. In this study, we investigated the effects of pretreatment of a bolus dose of enteral glutamine on ALI induced by OA in rats.

METHODS

Twenty-eight adult female Sprague-Dawley rats weighing 240-300 g were divided into four groups, 7 in each. Group I and group II received normal saline for 30 days, group III and group IV received glutamine at a dose of 1 g/kg for 10 days by gavage, and in group II and group IV 100 mg/kg OA was administered i.v. Histopathological examination of the lung was performed with light and electron microscopy. Levels of protein carbonyl, malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase levels were measured in tissue samples. Levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and total tissue oxidant status and total tissue antioxidant status were measured in serum samples.

RESULTS

Light microscopy showed that the total lung injury score of group IV was significantly lower than group II. Change in thickness of the fused basal lamina was not significantly different in groups II and IV under electron microscopy. TNF-α, IL-6, and IL-10 serum levels were higher in group II when compared to group I and significantly attenuated in group IV.

CONCLUSION

Pretreatment with a bolus dose of enteral glutamine minimized the extent of ALI induced by OA in rats.

Regulation of electrolyte transport with IL-1beta in rabbit distal colon

Interletrkin-1beta levels are elevated in inflammatory bowel disease. In this study the mechanism by which interleukin-1beta affects electrolyte transport in the rabbit distal colon, was investigated. Interleukin-1beta caused a delayed increase in short-circuit current (I(sc)) which was attributed to protein synthesis since the effect was inhibited by cycloheximide. The interleukin-1beta induced increase in I(sc) was not affected by amiloride treatment but was completely inhibited by bumetanide or in chloride-free buffer and by indomethacin. Prostaglandin E(2) levels increased in tissue treated with interleukin-1beta, but this increase was reversed by cycloheximide. These data suggest that interleukin-1beta causes its effect via a yet to be identified second messenger, by increasing chloride secretion through a prostaglandin E(2) mediated mechanism.

RNA from LPS-stirnulated macrophages induces the release of tumour necrosis factor-alpha and interleukin-1 by resident macrophages

The effect of exogenous RNA on many cellular functions has been studied in a variety of eukaryotic cells but there are few reports on macrophages. In the present study, it is demonstrated that cytoplasmatic RNA extracted from rat macrophages stimulated with Escherichia coli lipopolysaccharide (LPS), referred to as L-RNA, induced the release of TNF-α and IL-1 from monolayers of peritoneal resident macrophages. The activity of L-RNA was not altered by polymyxin B but was abolished by ribonuclease (RNase) pretreatment, indicating the absence of LPS contamination and that the integrity of the polynucleotide chain is essential for this activity. Both the poly A(−) and poly A(+) fractions obtained from L-RNA applied to oligo(dT)–cellulose chromatography induced TNF-α and IL-1 release. The L-RNA-induced cytokine release was inhibited by dexamethasone and seemed to be dependent on protein synthesis since this effect was abolished by cycloheximide or actinomycin-D. The LPS-stimulated macrophages, when pre-incubated with [5-³H]-uridine, secreted a trichloroacetic acid (TCA) precipitable material which was sensitive to RNase and KOH hydrolysis, suggesting that the material is RNA. This substance was also released from macrophage monolayers stimulated with IL-1β but not with TNF-α, IL-6 or IL-8. The substance secreted (³H-RNA) sediments in the 4–5S region of a 5–20% sucrose gradient. These results show that L-RNA induces cytokine secretion by macrophage monolayers and support the idea that, during inflammation, stimulated macrophages could release RNA which may further induce the release of cytokines by the resident cell population.

Induction of circulating phospholipase A(2) by intravenous administration of recombinant human tumour necrosis factor

We have examined the effects of intravenous infusion of recombinant human tumour necrosis factor (rh-TNF) on serum activity of phospholipase A(2) (PLA(2)) in patients with malignancies. Nine patients received a 24 h continuous intravenous infusion ranging from 1.0 x 10(5) U/m(2) to 3.0 x 10(5) U/m(2); 14 patients received a 5 day continuous intravenous infusion ranging from 0.5 x 10(5) U/m(2)/day to 3.0 10(5) U/m(2)/day. Twenty one of 23 patients responded with marked increases in serum PLA(2) activity that were detectable 3 h after the beginning of the rh-TNF infusion and reached maximum levels at 18 h with a mean increase of 16.2-fold. In patients receiving a 5 day rh-TNF infusion, the highest levels of PLA(2) were observed after the first day of infusion. Serum PLA(2) activity declined continuously to 2.9-fold above baseline at the end of the infusion. A significant correlation was noted between the dose of infused rh-TNF and the maximum increase in PLA(2) activity. To our knowledge, this is the first time that an association between intravenous TNF administration and induction of circulating PLA(2) in man has been established.

Impaired resolution of inflammatory response in the lungs of JF1/Msf mice following carbon nanoparticle instillation

BACKGROUND

Declined lung function is a risk factor for particulate matter associated respiratory diseases like asthma and chronic obstructive pulmonary disease (COPD). Carbon nanoparticles (CNP) are a prominent component of outdoor air pollution that causes pulmonary toxicity mainly through inflammation. Recently we demonstrated that mice (C3H/HeJ) with higher than normal pulmonary function resolved the elicited pulmonary inflammation following CNP exposure through activation of defense and homeostasis maintenance pathways. To test whether CNP-induced inflammation is affected by declined lung function, we exposed JF1/Msf (JF1) mice with lower than normal pulmonary function to CNP and studied the pulmonary inflammation and its resolution.

METHODS

5 μg, 20 μg and 50 μg CNP (Printex 90) were intratracheally instilled in JF1 mice to determine the dose response and the time course of inflammation over 7 days (20 μg dosage). Inflammation was assessed using histology, bronchoalveolar lavage (BAL) analysis and by a panel of 62 protein markers.

RESULTS

24 h after instillation, 20 μg and 50 μg CNP caused a 25 fold and 19 fold increased polymorphonuclear leucocytes (PMN) respectively while the 5 μg represented the 'no observable adverse effect level' as reflected by PMN influx (9.7 × 10E3 vs 8.9 × 10E3), and BAL/lung concentrations of pro-inflammatory cytokines. Time course assessment of the inflammatory response revealed that compared to day1 the elevated BAL PMN counts (246.4 × 10E3) were significantly decreased at day 3 (72.9 × 10E3) and day 7 (48.5 × 10E3) but did not reach baseline levels indicating slow PMN resolution kinetics. Strikingly on day 7 the number of macrophages doubled (455.0 × 10E3 vs 204.7 × 10E3) and lymphocytes were 7-fold induced (80.6 × 10E3 vs 11.2 × 10E3) compared to day1. At day 7 elevated levels of IL1B, TNF, IL4, MDC/CCL22, FVII, and vWF were detected in JF1 lungs which can be associated to macrophage and lymphocyte activation.

CONCLUSION

This explorative study indicates that JF1 mice with impaired pulmonary function also exhibits delayed resolution of particle mediated lung inflammation as evident from elevated PMN and accumulation of macrophages and lymphocytes on day 7. It is plausible that elevated levels of IL1B, IL4, TNF, CCL22/MDC, FVII and vWF counteract defense and homeostatic pathways thereby driving this phenomenon.

Antimicrobial activity of PLUNC protects against Pseudomonas aeruginosa infection

Epithelial antimicrobial activity may protect the lung against inhaled pathogens. The bactericidal/permeability-increasing protein family has demonstrated antimicrobial activity in vitro. PLUNC (palate, lung, and nasal epithelium associated) is a 25-kDa secreted protein that shares homology with bactericidal/permeability-increasing proteins and is expressed in nasopharyngeal and respiratory epithelium. The objective of this study was to determine whether PLUNC can limit Pseudomonas aeruginosa infection in mice. Transgenic mice (Scgb1a1-hPLUNC) were generated in which human PLUNC (hPLUNC) was directed to the airway epithelium with the Scgb1a1 promoter. The hPLUNC protein (hPLUNC) was detected in the epithelium throughout the trachea and bronchial airways and in bronchoalveolar lavage fluid. Bronchoalveolar lavage fluid from transgenic mice exhibited higher antibacterial activity than that from wild type littermates in vitro. After in vivo P. aeruginosa challenge, Scgb1a1-hPLUNC transgenic mice displayed enhanced bacterial clearance. This was accompanied by a decrease in neutrophil infiltration and cytokine levels. More importantly, the overexpressed hPLUNC in Scgb1a1-hPLUNC transgenic mouse airway significantly enhanced mouse survival against P. aeruginosa-induced respiratory infection. These data indicate that PLUNC is a novel antibacterial protein that likely plays a critical role in airway epithelium-mediated innate immune response.

Effect of Panax ginseng on cytokine expression in bovine mammary glands at drying off

Biological response modifiers (BRM) are agents that modify the host's response to pathogens with resultant beneficial prophylactic or therapeutic effects. The objectives of this study were to describe the immunomodulatory effects of Panax ginseng (GS) on bovine mammary glands at the end of lactation. Eight mammary quarters from six nonpregnant cows in late lactation were infused with 10mL of BRM (3mg/mL), six quarters were treated with placebo (vehicle alone) and six quarters were maintained as uninoculated controls. Milk samples were collected at different time points for detection of specific cytokines mRNA by RT-PCR and Western blotting assay. A significant increase of IL-1α, IL-1β and TNF-α mRNA expression was observed in BRM-treated compared with placebo-treated quarters at 48h post-treatment (pt) (P<0.05). A 17kDa TNF-α band expressed a sharp elevation at 24h and reduction in its level at 48h pt in BRM-treated quarters. Differences in this cytokine level between 24 and 48h pt times were significant (P<0.05). GS extract inoculation at drying off was associated with somatic cell counts increase, cytokines mRNA transcription and the presence of TNF-α in milk and can therefore exert immunomodulating effects in bovine mammary gland at drying off.

Effects of dietary glutamine supplementation on lung injury induced by lipopolysaccharide administration

Acute lung injury (ALI) is a critical syndrome associated with respiratory dysfunction, and neutrophils are considered to be central to the pathogenesis of ALI. This study investigated the effects of glutamine (Gln) on neutrophil recruitment in a model of lipopolysaccharide (LPS)-induced ALI. C57BL/6 mice were fed a standard diet either with casein as the nitrogen source or with 25% of total nitrogen replaced by Gln. After 10 days, intratracheal instillation of LPS was used to induce ALI. Mice were killed at 0, 6, 12, and 24 h after LPS administration (n = 10/group). Bronchoalveolar lavage fluid and lung tissues were collected for further analysis. The results showed that, compared with the control group, lipid peroxide levels in the lungs were higher at 12 and 24 h after LPS administration in the Gln group. CXC chemokines as well as tumor necrosis factor-alpha were significantly elevated and reached peaks at 6 h in the Gln group, which was earlier than in the control group. Histopathological findings showed that the thickening of alveolar septal space was extensive in the Gln group 24 h and 2 wk after LPS. Also, greater amounts of collagen had accumulated in lung tissue in the Gln group. This study indicates that dietary Gln administration resulted in higher inflammatory cytokine production, with more neutrophils recruited at the early stage of ALI. These results were consistent with the histopathological findings that Gln supplementation causes more severe interstitial inflammation and fibrosis in a model of ALI induced by LPS.

The multicomponent phytopharmaceutical SKI306X inhibits in vitro cartilage degradation and the production of inflammatory mediators

Clinical studies have demonstrated that SKI306X, a purified preparation of three medicinal plants, relieves joint pain and improves functionality in osteoarthritis patients. To study the biological action of SKI306X, bovine cartilage explants and human peripheral blood mononuclear cells (PBMC) were stimulated with IL-1 beta and lipopolysaccharide (LPS) respectively, in the presence or absence of SKI306X and its individual composites. All tested compounds inhibited dose-dependently IL-1 beta-induced proteoglycan release and nitric oxide production by cartilage, indicating cartilage protective activity. SKI306X and two of its compounds inhibited PGE(2), TNF-alpha and IL-1 beta production by LPS-stimulated PBMC, indicating anti-inflammatory activity. These results demonstrate that the biological effect of SKI306X is at least bipartite: (1) cartilage protective and (2) anti-inflammatory. The observed anti-inflammatory effects may provide an explanation for the outcome of the clinical studies. Long-term clinical trails are necessary to elucidate whether the in vitro cartilage protective activity results in disease-modifying effects.

Hydrated keratinocytes reduce collagen synthesis by fibroblasts via paracrine mechanisms

Regulating collagen metabolism can control hypertrophic scars in cutaneous wounds. Hypertrophic scars can be reduced by occlusive dressings such as silicone sheeting; however, their mechanism is still unknown. We hypothesized that hydration of keratinocytes reduces the collagen secretion of fibroblasts by modifying the cytokine levels. Stratified human epidermal keratinocytes and confluent human dermal fibroblasts were co-cultured serum free for 72 hours. Keratinocytes were either kept at the air interface or hydrated. Messenger RNA (mRNA) levels of interleukin-1 (IL-1)alpha, IL-1beta, tumor necrosis factor alpha (TNF-alpha), keratinocyte growth factor (KGF), and procollagen-1 were analyzed by real-time reverse transcription-polymerase chain reaction. Secretion of cytokines into conditioned media was quantified by enzyme-linked immunosorbent assay and collagen content by Western blot. The content of collagen-I decreased by 44% in the presence of hydrated keratinocytes. Co-culture with air-treated keratinocytes decreased collagen-I only by 23%. Co-cultured hydrated keratinocytes had significantly higher TNF-alpha mRNA (172%) than hydrated keratinocytes. At the protein level, there was an overall trend toward increased TNF-alpha levels in hydrated cultures. IL-1beta secretion decreased significantly under hydration (42% monoculture, 58% co-culture). Co-culture stimulated a 240% increase of KGF mRNA in fibroblasts compared with monocultured fibroblasts. Fibroblasts secreted 4.5-fold more KGF in hydrated co-cultures and sixfold more KGF in air-treated co-cultures. Hydration of keratinocytes modifies important paracrine interactions between keratinocytes and fibroblasts and reduces collagen-1, which supports the hypothesis that hydration of the epidermis and restoration of water barrier function play an important role in scar formation.

Synovial fluid OX40T lymphocytes of patients with rheumatoid arthritis display a Th2/Th0 polarization

Rheumatoid arthritis (RA) is an autoimmune disease in which T-cell activation plays a pivotal role in the induction of articular damage. CD4+/OX40+ T cells accumulate in the synovial fluid (SF) of RA patients, which suggests that they are involved in the pathogenesis of the disease. In this study, we assessed the intracellular cytokine production of peripheral blood and SF CD4+ and CD4+/OX40+ T cells from RA patients in order to evaluate their role in this disorder. Our results show that SF CD4+ cells are predominantly interferon gamma (IFN-gamma)-positive and express a Th1-like cytokine pattern. In SF, significantly more CD4+/OX40+ T cells expressed interleukin-4 (IL-4) and IL4/IFN-gamma than IFN-gamma alone. Our data demonstrate that SF CD4+/OX40+ T cells express a Th2/Th0 cytokine profile, which suggests that they are involved in inflammatory responses in RA joints.

Conditional expression of interferon-γ to enhance host responses to pulmonary bacterial infection

Strategies to augment host defense against pulmonary infection run the risk of inducing excess pulmonary inflammation and tissue injury. To address this problem, we investigated conditional expression in lung tissue of the murine interferon-gamma (IFN-gamma) transgene. A recombinant adenoviral vector (AdTetIFN) was constructed by placing a murine IFN-gamma cDNA downstream of a tetracycline (Tet)-responsive promoter, inserted into a replication-defective adenoviral vector. Co-infection of target cells with AdTetIFN and a second vector encoding a reverse tetracycline controlled transactivator allowed doxycycline (Dox)-regulated IFN-gamma production. We then administered 10(8) plaque-forming units (PFU) of AdTetIFN to mice by intratracheal injection. When the mice were provided with Dox in drinking water (0.5mg/ml in 5% sucrose), there was significant release of IFN-gamma in lavage fluid by ELISA in comparison to mice on water/sucrose alone (399+/-74 pg/ml vs undetectable, p<0.01). IFN-gamma in lavage fluid was associated with upregulation of Class II Major histocompatibility complex markers on alveolar macrophages by flow cytometry, suggesting macrophage activation. We then injected AdTetIFN into mice three days prior to challenge with 10(4) CFU Klebsiella pneumoniae. Test mice were maintained on water+Dox and control mice on water+sucrose. Bacterial burden was assayed in lung tissue at serial intervals. At 24h after challenge, mice on doxycycline had significantly lower infection burden in comparison to mice on water/sucrose (0.77+/-0.05 colony forming units/lung for 10(8) PFU AdTetIFN plus Dox compared to 1.4+/-0.11 colony-forming units/lung for AdTetIFN without Dox, p<0.05). Survival of the vector treated mice given doxycycline in drinking water was also enhanced. Microscopic examination of lavaged cells showed a significant increase in pulmonary neutrophils in the AdTetIFN+Dox mice in comparison to AdTetIFN+sucrose mice (16+/-1.0 x 10(5) vs 10+0.8 cells/lung, p<0.05). We conclude that local release of IFN-gamma can be selectively activated to enhance neutrophil recruitment and host resistance to bacterial pneumonia.

Interleukin-8 levels in seminal plasma in chronic prostatitis/chronic pelvic pain syndrome and nonspecific urethritis

OBJECTIVE

To investigate whether a range of cytokines were detectable in the seminal plasma and urine of men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and nonspecific urethritis (NSU), and whether cytokine levels correlated with symptom severity in CP/CPPS.

PATIENTS AND METHODS

In all, 87 men participated, 33 with CP/CPPS, 31 with NSU, and 23 controls. Interleukin (IL)-1beta, IL-2, IL-6, IL-8 and IL-10 were measured in seminal plasma and first pass urine, and the results were correlated with scores for pain, urinary symptoms and quality-of-life impact using a validated symptom index, the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI).

RESULTS

Seminal plasma levels of IL-8 were higher in men with CP/CPPS and NSU than in controls (P < 0.001), and the levels correlated with NIH-CPSI symptom scores in men with CP/CPPS. There were no significant differences in urinary IL-8 levels in the three groups, and no significant differences in levels of the other cytokines in either semen or urine.

CONCLUSION

Semen IL-8 levels correlate with subjective symptoms in men with CP/CPPS. IL-8 might contribute to the pathophysiology of CP/CPPS and NSU, and elevated levels might be a useful marker of the condition.

Absence of IL-1 Receptor Antagonist Impaired Wound Healing along with Aberrant NF-κB Activation and a Reciprocal Suppression of TGF-β Signal Pathway

Although enhanced expression of IL-1 family proteins, including IL-1alpha, IL-1beta, and IL-1 receptor antagonist (IL-1ra) during wound healing has been observed, the pathophysiological roles of these factors, particularly IL-1ra, still remain elusive. We explored skin wound-healing processes in IL-1ra-deficient mice. Compared to wild-type (WT) mice, IL-1ra-deficient mice exhibited impaired wound healing, as evidenced by attenuated collagen deposition and delayed neovascularization. In contrast, neutrophil recruitment was significantly exaggerated, with the augmented expression of IL-1s, TNF-alpha, and CXC chemokines, MIP-2 and KC, in IL-1ra-deficient mice compared with WT mice. Because the transcription of these proinflammatory cytokines and CXC chemokines requires the activation of NF-kappaB, a major target of IL-1- and TNF-alpha-mediated signal pathway, we examined the activation states of NF-kappaB. Nuclear translocation of NF-kappaB p65 was significantly enhanced and prolonged in IL-1ra-deficient mice, compared to that in WT mice. The cross-talk between NF-kappaB and TGF-beta-mediated signals has been proposed based on in vitro observations. Indeed, compared to WT mice, the amounts of total and phosphorylated Smad2 and Smad3 were decreased with a reciprocal increase in the amount of Smad7 in skin wound sites of IL-1ra-deficient mice. Moreover, the gene expression of vascular endothelial growth factor, a target gene of TGF-beta1, was decreased in IL-1ra-deficient mice. Thus, the absence of IL-1ra may suppress TGF-beta-mediated signaling pathway, which is crucial for collagen deposition and vascular endothelial growth factor-mediated neovascularization in wound healing.

Calcitonin gene-related peptide inhibits interleukin-1beta-induced endogenous monocyte chemoattractant protein-1 secretion in type II alveolar epithelial cells

As important multifunctional cells in the lung, alveolar epithelial type II (AEII) cells secrete numerous chemokines on various stimuli. Our previous data showed that AEII cells also express the neuropeptide calcitonin gene-related peptide (CGRP) and the proinflammatory factor interleukin (IL)-1beta induces CGRP secretion in the A549 human AEII cell line. In the present study, the CGRP-1 receptor antagonist human (h)CGRP(8-37) (0.1-1 nM) greatly amplified the production of IL-1beta-induced monocyte chemoattractant protein (MCP)-1. The inhibition of CGRP expression by small interfering RNA significantly increased MCP-1 secretion on IL-1beta stimulation. However, exogenous hCGRP (10-100 nM) suppressed IL-1beta-evoked MCP-1 secretion in MCP-1 promoter activity, and CGRP gene stably transfected cell clones significantly inhibited both the mRNA and protein levels of MCP-1 induced by IL-1beta. These data imply that AEII-derived CGRP suppressed IL-1beta-induced MCP-1 secretion in an autocrine/paracrine mode. Subsequent investigation revealed that CGRP inhibited IL-1beta-evoked NF-kappaB activity by suppressing IkappaBalpha phosphorylation and degradation. Moreover, CGRP attenuated IL-1beta-induced reactive oxygen species (ROS) formation, the early event in proinflammatory factor signaling. We previously showed that the CGRP inhibitory effect was mediated by elevated intracellular cAMP and show here that analogs of cAMP, 8-bromoadenosine 3',5'-cyclic monophosphothioate and the Sp isomer of adenosine 3',5'-cyclic monophosphothioate, mimicked the CGRP suppressive effect on IL-1beta-induced ROS formation, NF-kappaB activation, and MCP-1 secretion. Thus increased endogenous CGRP secretion in lung inflammatory disease might eliminate the excessive response by elevating the cAMP level through inhibiting the ROS-NF-kappaB-MCP-1 pathway.

Pharmacological inhibition of Mannheimia haemolytica lipopolysaccharide and leukotoxin-induced cytokine expression in bovine alveolar macrophages

The inflammatory cytokines tumor necrosis factor-alpha (TNFalpha), interleukin-1 beta (IL-1beta), and interleukin-8 (IL-8) are believed to contribute to the pathogenesis of lung injury in bovine pneumonic mannheimiosis (BPM) caused by Mannheimia (Pasteurella) haemolytica. Inflammatory cytokines may, therefore, represent therapeutic targets to be modulated for the purpose of treating or preventing this important disease of cattle. The purpose of this study was to evaluate the ability of six pharmacological agents to suppress the expression of TNFalpha, IL-1beta, and IL-8 genes and proteins in bovine alveolar macrophages (AM) exposed to M. haemolytica lipopolysaccharide (LPS) and leukotoxin (LktA) in vitro. The compounds tested included dexamethasone (DEX), tetrahydropapaveroline (THP), pentoxifylline (PTX), rolipram (ROL), SB203580 (SB), and thalidomide (THL). Cytokine expression was induced by the addition of purified M. haemolytica LPS and LktA to AM cell cultures following pretreatment with inhibitor compounds. Secretion of TNFalpha, IL-1beta, and IL-8 proteins into the cell culture supernatant was measured using enzyme-linked immunosorbent assays, and steady-state accumulation of cytokine-specific mRNA was measured by northern blot analysis. Dose-dependent inhibition of cytokine secretion occurred in response to pretreatment of AM with DEX (TNFalpha, IL-1beta, IL-8), THP (TNFalpha, IL-1beta, IL-8), PTX (TNFalpha, IL-1beta, IL-8), ROL (TNFalpha, IL-1beta), and SB (TNFalpha, IL-8). Significant dose-dependent inhibition of cytokine mRNA expression occurred in response to pretreatment with DEX (TNFalpha, IL-1beta, IL-8), THP (TNFalpha, IL-1beta, IL-8), and PTX (TNFalpha). DEX was the most effective inhibitor by far; pretreatment with this compound yielded greater than 95% inhibition of cytokine gene and protein expression over a broad range of concentrations. These findings demonstrate that DEX, THP, PTX, ROL, and SB are capable of suppressing inflammatory cytokine secretion by bovine AM in vitro. If pulmonary cytokine secretion may be similarly inhibited in vivo, anti-cytokine therapy may represent a novel strategy for the management of BPM.

Protective effect of dexamethasone in experimental bovine pneumonic mannheimiosis

Clinical and experimental studies provide unequivocal evidence that neutrophils participate in the pathogenesis of lung injury in bovine pneumonic mannheimiosis (BPM). Since the inflammatory cytokines tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-8 play a central role in the recruitment and activation of neutrophils, we hypothesize that pharmacological inhibition of their expression may prevent or reduce the inflammatory lung injury that is characteristic of the disease. The purpose of this study was to determine whether systemic therapy with dexamethasone sodium phosphate (DEX), a potent inhibitor of inflammatory cytokine synthesis, ameliorates disease development in an in vivo experimental model of BPM. Four experimental calves were treated intravenously with DEX (2 mg/kg 6 h prior to infection, 2 mg/kg immediately prior to infection, and 1 mg/kg every 12 h thereafter), while two placebo-treated control calves received dose-matched volumes of sterile saline. Disease was induced in the left lungs of the six calves by endobronchial administration of Mannheimia haemolytica. Clinical disease was characterized using a non-parametric scoring system, and the extent of gross pulmonary pathology affecting the left lung 48 h post-infection (PI) was determined using morphometric methods. Disease scores for DEX-treated calves were significantly lower than those for placebo-treated controls at all time points beyond 2 h PI (P<0.05) and the percent volume of the left lung exhibiting gross pneumonic lesions was significantly lower in DEX-treated calves (6.0+/-1.1%) as compared to controls (68.9+/-13.3%), P<0.05. In addition, histopathological lesions were less severe and extensive in DEX-treated calves. These findings indicate that pharmacological modulation of pulmonary inflammation may represent an alternative approach to control this disease. Successful implementation of this strategy will require additional research to identify drug agents that target the expression of cytokines and other inflammatory mediators without compromising host immune responses.

The cytokine markers in Staphylococcus aureus mastitis of bovine mammary gland

TaqMan real time PCR was used to study the transcriptional activity of the bovine IL-2, IL-6, IL-12p40, IFN-gamma, TNF-alpha and granulocyte-monocyte colony stimulating factor of whole milk cells in bovine mammary gland experimentally infected with Staphylococcus aureus. Cytokine transcriptional activity was monitored at 7, 24 and 32 h Post-infection (Pi). IL-12 and TNF-alpha levels were significantly elevated at 24 h Pi followed by sharp decrease at 32 h pi. IL-2 level was decreased at 32 h pi. IL-12 and IFN-gamma showed a significant interaction at 24 h pi. The significant elevations of the IL-12 and TNF-alpha transcriptional level most likely indicate their important role in regulation of the immune responses of bovine mammary gland in S. aureus infection. Depression of IL-2 could reflect the suppressive nature of the S. aureus mastitis.

Influences of naturally occurring and experimentally induced porcine pneumonia on blood parameters

It had been the objective of the studies described to establish local and systemic changes by naturally occurring pneumonia or pneumonia experimentally induced by Pasteurella multocida and Haemophilus parasuis in swine. Acute and chronic pneumonia was found to alter the cytokine level of lung lavage fluid and affect the composition and function of blood cells, especially with regard to phagocytosis, radical formation and cell surface receptors. Interleukin-6 levels in blood plasma rose 24h after experimental intrabronchial infection. The influences of the changes on growth and meat quality are discussed.

Divergent mechanisms of action of the inflammatory cytokines interleukin 1-beta and tumour necrosis factor-alpha in mouse cremasteric venules

1. Protein synthesis dependency and the role of endogenously generated platelet activating factor (PAF) and leukotriene B(4) (LTB(4)) in leukocyte migration through interleukin-1beta (IL-1beta)- and tumour necrosis factor-alpha (TNFalpha)-stimulated mouse cremasteric venules was investigated using established pharmacological interventions and the technique of intravital microscopy. 2. Based on previously obtained dose-response data, 30 ng rmIL-1beta and 300 ng rmTNFalpha were injected intrascrotally (4 h test period) to induce comparable levels of leukocyte firm adhesion and transmigration in mouse cremasteric venules. 3. Co-injection of the mRNA synthesis inhibitor, actinomycin D (0.2 mg kg(-1)), with the cytokines significantly inhibited firm adhesion (49+/-13.6%) and transmigration (67.2+/-4.2%) induced by IL-1beta, but not TNFalpha. 4. In vitro, TNFalpha (1-100 ng ml(-1)), but not IL-1beta, stimulated L-selectin shedding and increased beta(2) integrin expression on mouse neutrophils, as quantified by flow cytometry. 5. The PAF receptor antagonist, UK-74,505 (modipafant, 0.5 mg kg(-1), i.v.), had no effect on adhesion induced by either cytokine, but significantly inhibited transmigration induced by IL-1beta (66.5+/-4.5%). 6. The LTB(4) receptor antagonist, CP-105,696 (100 mg kg(-1), p.o.), significantly inhibited both IL-1beta induced adhesion (81.4+/-15.2%) and transmigration (58.7+/-7.2%), but had no effect on responses elicited by TNFalpha. Combined administration of the two antagonists had no enhanced inhibitory effects on responses induced by either cytokine. 7. The data indicate that firm adhesion and transmigration in mouse cremasteric venules stimulated by IL-1beta, but not TNFalpha, is protein synthesis dependent and mediated by endogenous generation of PAF and LTB(4). Additionally, TNFalpha but not IL-1beta, can directly stimulate mouse neutrophils in vitro. The findings provide further evidence to suggest divergent mechanisms of actions of IL-1beta and TNFalpha, two cytokines often considered to act via common molecular/cellular pathways.

Effects of various applications of lipopolysaccharides on blood parameters of pigs

In five experiments, lipopolysaccharides (LPS) of Escherichia coli O26:B6 and O111:B4 were applied intravenously, intramuscularly, subcutaneously or intrabronchially in doses of 5000-15,000 U/kg body mass to a total of 47 weaner pigs and compared with the application of sodium chloride. Different parameters of blood cells were investigated, including cell numbers, in vivo interleukin secretion, radical formation, phagocytosis capacity and IL-6 as well as TNFalpha formation ex vivo. Non-specific effects and dependencies on the type of application and LPS dose are discussed.

Effects of dexamethasone on proteoglycan content and gene expression of IL-1beta-stimulated osteoarthrotic chondrocytes in vitro

We studied the effects of dexamethasone on proteoglycan (PG) concentration and gene expression in human osteoarthrotic chondrocytes stimulated with IL-1beta. Cartilage samples were taken from 7 patients with osteoarthrosis of the knee and chondrocytes cultivated in alginate beads. Dexamethasone was added in three concentrations (10(-5), 10(-6), 10(-7) M) to IL-1beta (100 pg/nL)-stimulated chondrocytes. PG concentration was estimated by a dimethylmethylene blue assay. To assess cell proliferation, DNA content was measured fluorometrically. Quantitative Lightcycler-PCR was used to estimate the mRNA levels of stromelysin-1 (MMP-3) and aggrecan (AGG). The proliferation rate was unchanged in all treatment groups. IL-1beta increased MMP-3 expression by 44% and inhibited AGG expression by 16%, but PG-concentration was reduced by 7%. The addition of dexamethasone to IL-1beta-stimulated chondrocytes further reduced the PG concentration by 19% at 10(-5) M and by 17% at 10(-7) M. The MMP-3 expression was inhibited between 27-53% and the AGG expression between 30-46% by dexamethasone. In osteoarthrotic chondrocytes, dexamethasone in an appropriate dose range reduced the expression of MMP-3 and AGG at the same time. The resulting decrease in PG concentration should be considered when using intraarticular corticosteroids to treat an osteoarthrotic joint.

Cytokines in coagulation and thrombosis: a preclinical and clinical review

The cytokine network is a complex and dynamic system, involved in numerous biological responses in the human body. This review of the current literature describes the role of cytokines and their interaction with the coagulation system, specifically in the maintenance of the thrombo-hemorrhagic balance in vivo in human subjects and in animals. In general, cytokines are thrombogenic, but they are amenable to therapeutic manipulations and hence are a potentially attractive tool in the clinician's armamentarium. Studies of the effects of cytokines in vivo are difficult because cytokines act in a very finite microenvironment and, although their actions are significant, they are transient. Most of the available clinical data related to interactions between cytokines and the coagulation system focuses on the role of tumor necrosis factor-alpha and interleukin-1 in septicemia and septic shock. However, several other cytokines and related proteins, such as platelet activating factor and plasminogen activator inhibitor, are also known to influence coagulation and thrombosis. These factors interact closely with cytokines, and have been included in this review for a better understanding of their interactions with traditional cytokines. Studies that utilize cell culture systems do not accurately model the in vivo status of this complex system and, hence, this review has excluded such studies. The role of the cytokine network in coronary artery disease, angiogenesis, or neoplasia has been addressed elsewhere by other workers and is not discussed here. By emphasizing important in vivo interactions, the intention of this review is to serve as an impetus to further translational research, both clinical and in the laboratory.

A549 cells can express interleukin-16 and stimulate eosinophil chemotaxis

Alveolar epithelial cells produce many types of chemokines such as regulated on activation, normal T cells expressed and secreted (RANTES), eotaxin induced by interleukin (IL)-1 beta, or tumor necrosis factor (TNF)-alpha and may contribute to allergic disease by recruiting eosinophils. However, identification of the eosinophil chemotacic activity (ECA) release from A549 cells, an alveolar type II cell line, has not yet been completed. Recently, IL-16 was also reported to be a potent chemotactic stimulus for CD4(+) T lymphocytes and eosinophils in asthma and other pulmonary diseases. To test the possibility that alveolar epithelial cells produce IL-16, we analyzed RNA and culture supernatant from A549 cells by reverse transcription/ polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The release of ECA from A549 cells was assessed using a blind-well chemotactic chamber. IL-16 release was increased in a concentration-dependent manner by stimulation with IL-1 beta or TNF-alpha. A549 cells also expressed IL-16 messenger RNA. The combination of IL-4 and IL-1 beta or TNF-alpha had an additive effect on IL-16 production. The release of ECA was induced by IL-1 beta or TNF-alpha in a dose-dependent manner. The combination of these cytokines had a greater effect than one alone. The blockade of eotaxin and IL-16 caused 70% inhibition of ECA, but anti-RANTES antibodies only caused 30% inhibition and anti-IL-8 antibodies failed to affect inhibition. These findings suggest a role for chemokines released by alveolar epithelial cells in the recruitment of eosinophils into the lung in pulmonary disorders such as asthma and interstitial lung diseases, and suggested that eotaxin and IL-16 are potent and effective eosinophil chemoattractants.

Role of macrophages and inflammatory mediators in chemically induced toxicity

Macrophages are critical cellular effectors of nonspecific host defense. They are also potent secretory cells releasing an array of mediators including proinflammatory and cytotoxic cytokines and growth factors, bioactive lipids, hydrolytic enzymes and reactive oxygen and nitrogen intermediates, each of which has been implicated in tissue injury. The research in our laboratories has focused on analyzing the role of macrophages in chemically induced injury in the lung and the liver. In both these tissues, a localized accumulation of macrophages is observed following toxicant exposure. This is directly correlated with the generation of cytotoxic inflammatory mediators at these sites. Moreover, when macrophage functioning is blocked, pulmonary and hepatic injury induced by toxicants such as ozone or acetaminophen is prevented. These findings provide direct support for our hypothesis that macrophages contribute to tissue injury. Approaches using pharmacologic inhibitors and transgenic animals are currently being used to evaluate the specific macrophage-derived products involved in the pathogenic process. Our results suggest that the extent to which a particular mediator contributes to injury depends on the nature of the toxicant, the target tissue, and quantities of the mediator produced.

Interactions between the alpha(2)-adrenergic and the prostaglandin response in the regulation of macrophage-derived tumor necrosis factor

Mediators such as prostaglandin E(2) (PGE(2)) and norepinephrine (NE) regulate macrophage (M&phi;) responsiveness. Activation of alpha(2)-adrenergic receptors on M&phi; potentiates lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNFalpha) production. PGE(2) inhibits LPS-stimulated TNFalpha production and gene expression, a response that can be desensitized by pretreatment of M&phi; with PGE(2). We have determined that concomitant pretreatment of M&phi; with PGE(2) and the alpha(2)-adrenergic agonist UK-14304 (UK) can prevent the PGE(2)-induced desensitization. PGE(2) concentration-effect curves have been determined for the inhibition of LPS-stimulated TNFalpha production by murine peritoneal M&phi;. The addition of 10 nM UK to M&phi; in culture significantly shifts the PGE(2) concentration-effect curve to the right; pretreatment of M&phi; with UK significantly shifts the PGE(2) concentration-effect curve to the left; and pretreatment with the cyclooxygenase inhibitor, indomethacin, increases the maximum response of PGE(2). Preincubation of M&phi; with PGE(2) (0.5 h) followed by washing significantly shifts the subsequent PGE(2) concentration-effect curve to the right. Concomitant preincubation of M&phi; with PGE(2) and UK prevents this rightward shift, an effect that is blocked by the alpha(2)-adrenergic receptor antagonist yohimbine. Northern blot analysis demonstrates that UK increases LPS-induced TNFalpha mRNA accumulation, and this is blocked by yohimbine, while PGE(2) decreases TNFalpha mRNA accumulation. Preincubation of M&phi; with PGE(2) prevents PGE(2) regulation of TNFalpha mRNA, and concomitant preincubation of M&phi; with PGE(2) and UK reverses this effect. These investigations support the role of NE as a regulator of M&phi; TNFalpha production, a response that has functional interactions with M&phi; sensitivity to PGE(2).

Tumour necrosis factor alpha enhances the expression of hydroxyl lyase, cytoplasmic antiproteinase-2 and a dual specificity kinase TTK in human chondrocyte-like cells

Tumour necrosis factor alpha (TNF-alpha) is a cytokine with pleiotropic effects on cells ranging from proliferation to apoptosis. These biological effects of TNF-alpha are believed to be elicited by the induction or enhancement of the expression of TNF-alpha responsive genes in the target cells. TNF-alpha is pro-inflammatory and a principal mediator in the pathogenesis of arthritis. The activation of an inflammatory cascade by TNF-alpha in arthritis results in the degradation of cartilage, joint destruction and loss of function. Because TNF-alpha is an important mediator in the pathogenesis of arthritis, the present study addresses the identification of novel TNF-alpha responsive genes in HTB-94 cell line which is of human origin and maintains a chondrocytic phenotype. The three identified cDNAs were previously not known to be induced or upregulated by TNF-alpha in chondrocytes or cells of chondrocytic lineage. One of the identified cDNAs had sequence similarity to human hydroxyl lyase mRNA (PLOD), an enzyme involved in collagen biosynthesis and its metabolism; the second cDNA had sequence similarity to the human cytoplasmic anti-proteinase-2 mRNA (CAP-2), a member of a group of proteins shown to be associated with protecting cells from TNF-alpha-induced apoptosis; and the third cDNA had sequence similarity to a dual specificity kinase, TTK, which is associated with cell proliferation. Relative gene expression level analysis by PCR and by Northern blotting revealed that treatment with TNF-alpha enhanced the expression of PLOD, CAP2 and TTK transcripts which confirmed the results obtained with display gels. Furthermore, TTK mRNA expression was also induced in human articular chondrocytes treated with TNF-alpha but not in untreated chondrocytes. Our results suggest that these genes may play a role in chondrocytic responses to TNF-alpha-mediated stimuli affecting the cartilage homeostasis.

Constitutive and cytokine-stimulated expression of eotaxin by human airway smooth muscle cells

Airway eosinophilia is a prominent feature of asthma that is believed to be mediated in part through the expression of specific chemokines such as eotaxin, a potent eosinophil chemoattractant that is highly expressed by epithelial cells and inflammatory cells in asthmatic airways. Airway smooth muscle (ASM) has been identified as a potential source of cytokines and chemokines. The aim of the present study was to examine the capacity of human ASM to express eotaxin. We demonstrate that airway myocytes constitutively express eotaxin mRNA as detected by RT-PCR. Treatment of ASM for 24 h with different concentrations of TNF-alpha and IL-1beta alone or in combination enhanced the accumulation of eotaxin transcripts. Maximal mRNA expression of eotaxin was shown at 12 and 24 h following IL-1beta and TNF-alpha stimulation, respectively. The presence of immunoreactive eotaxin was demonstrated by immunocytochemistry, and constitutive and cytokine-stimulated release of eotaxin was confirmed in ASM culture supernatants by ELISA. Strong signals for eotaxin mRNA and immunoreactivity were observed in vivo in smooth muscle in asthmatic airways. In addition, chemotaxis assays demonstrated the presence of chemoattractant activity for eosinophils and PBMCs in ASM supernatants. The chemotactic responses of eosinophils were partly inhibited with antibodies directed against eotaxin or RANTES, and a combined blockade of both chemokines causes > 70% inhibition of eosinophil chemotaxis. The results of this study suggest that ASM may contribute to airway inflammation in asthma through the production and release of eotaxin.

Opposing effects of tumour necrosis factor alpha and hyperosmolarity on Na+/myo-inositol co-transporter mRNA levels and myo-inositol accumulation by 3T3-L1 adipocytes

Tumour necrosis factor alpha (TNF-alpha) regulates the transport of myo-inositol in 3T3-L1 adipocytes. Treating 3T3-L1 adipocytes with TNF-alpha decreases Na+/myo-inositol co-transporter (SMIT) mRNA levels and myo-inositol accumulation in a concentration-and time-dependent manner. TNF-alpha decreases the V'max for high-affinity myo-inositol transport with little change in the K'm. Studies with actinomycin D suggest that RNA synthesis is required for the TNF-alpha-induced effect on SMIT mRNA levels. In contrast with the effect of TNF-alpha, hyperosmolarity increases SMIT mRNA levels and myo-inositol accumulation in 3T3-L1 adipocytes. Hyperosmolarity increases SMIT gene expression as evidenced by the inhibition of hyperosmotic induction of SMIT mRNA levels by actinomycin D, and of myo-inositol accumulation by actinomycin D and cycloheximide. TNF-alpha and osmotic stress have previously been shown to activate similar signal transduction pathways in mammalian cells. In 3T3-L1 adipocytes, both TNF-alpha and hyperosmolarity increase mitogen-activated protein kinase kinase pathway activity; however, with the possible exception of c-Jun N-terminal kinase, this pathway does not seem to regulate SMIT mRNA levels or myo-inositol accumulation. TNF-alpha activates nuclear factor kappaB (NF-kappaB) in 3T3-L1 adipocytes but, unlike the effect of TNF-alpha on cultured endothelial cells, NF-kappaB does not seem to contribute to the regulation by TNF-alpha of SMIT gene expression in 3T3-L1 adipocytes. Therefore other signal transduction pathways must be considered in the regulation by TNF-alpha of SMIT mRNA levels and activity. Thus TNF-alpha and hyperosmolarity have opposing effects on SMIT mRNA levels and activity in 3T3-L1 adipocytes. Because myo-inositol in the form of phosphoinositides is an important component of membranes and signal transduction pathways, the regulation of myo-inositol metabolism by TNF-alpha might represent another mechanism by which TNF-alpha regulates adipocyte function.

A Peptidomimetic Antagonist of TNF-α-Mediated Cytotoxicity Identified from a Phage-Displayed Random Peptide Library

Phage-displayed peptide libraries represent a vast collection of peptide sequences that can be used to identify novel therapeutic molecules. In this report, a 15-mer phage-displayed peptide library was used to identify potential TNF-α antagonists. After direct interaction of recombinant human TNF-α with the library, four randomly selected phage clones were shown to inhibit in a dose-dependent fashion both mouse and human TNF-α-induced cytotoxicity in vitro. DNA sequencing of the positive clones revealed a common amino acid sequence that does not bear any structural similarity to the known primary structures of the extracellular domains of either 55-kDa or 75-kDa TNF receptors. This sequence was synthesized, and the peptidomimotope was shown i) to bind to the recombinant human TNF-α using surface plasmon resonance (biosensor) technology and ii) to inhibit both recombinant mouse and human TNF-α-induced cytotoxicity in vitro in a dose-dependent fashion.

These findings highlight the potential of phage-displayed random peptide libraries for the identification of novel low molecular antagonistic molecules that can block the biologic activities of TNF-α.