TNF-alpha mediates chemokine and cytokine expression and renal injury in cisplatin nephrotoxicity

The purpose of these studies was to examine the role of cytokines in the pathogenesis of cisplatin nephrotoxicity. Injection of mice with cisplatin (20 mg/kg) led to severe renal failure. The expression of cytokines, chemokines, and ICAM-1 in kidney was measured by ribonuclease protection assays and RT-PCR. We found significant upregulation of TNF-alpha, TGF-beta, RANTES, MIP-2, MCP-1, TCA3, IL-1beta, and ICAM-1 in kidneys from cisplatin-treated animals. In addition, serum, kidney, and urine levels of TNF-alpha measured by ELISA were increased by cisplatin. Inhibitors of TNF-alpha production (GM6001, pentoxifylline) and TNF-alpha Ab's reduced serum and kidney TNF-alpha protein levels and also blunted the cisplatin-induced increases in TNF-alpha, TGF-beta, RANTES, MIP-2, MCP-1, and IL-1beta, but not ICAM-1, mRNA. In addition, the TNF-alpha inhibitors also ameliorated cisplatin-induced renal dysfunction and reduced cisplatin-induced structural damage. Likewise, TNF-alpha-deficient mice were resistant to cisplatin nephrotoxicity. These results indicate cisplatin nephrotoxicity is characterized by activation of proinflammatory cytokines and chemokines. TNF-alpha appears to play a central role in the activation of this cytokine response and also in the pathogenesis of cisplatin renal injury.     

Opiate modulation of hemodynamic, hormonal, and cytokine responses to hemorrhage

The aim of the present study was to examine the role of opiate receptor activation in modulating the hemodynamic, neuroendocrine, and tissue (lung and spleen) cytokine responses to fixed pressure (40 mm Hg) hemorrhage. Chronically catheterized, conscious unrestrained non-heparinized male Sprague-Dawley rats were pretreated with either naltrexone (15 mg/kg intraperitoneally in 0.5 mL of saline) or saline (0.5 mL) 15 min prior to hemorrhage followed by fluid resuscitation with Ringer's lactate. Animals were sacrificed at completion of the 60-min resuscitation period. Blood loss required to achieve mean arterial blood pressure (MABP) of 40 mm Hg was higher in naltrexone-treated animals than in time-matched saline controls (4.4+/-0.2 versus 3.7+/-0.2 mL/100 g BW, P< 0.05). Hemorrhage increased plasma levels of corticosterone (30%) and ACTH (3-fold) within 15 min. Naltrexone prevented the hemorrhage-induced rise in corticosterone without affecting the rise in ACTH. Hemorrhage increased beta-endorphin levels (4-fold) and produced an immediate (5 min) and progressive increase in circulating epinephrine and norepinephrine levels reaching values that were 50- and 20-fold, respectively, higher than basal. Pre-treatment with naltrexone did not alter the time course or magnitude of the hemorrhage-induced increases in plasma beta-endorphin or catecholamines. Hemorrhage increased lung and spleen content of TNF (60%), IL-1alpha (300%), IL-6 (40%-60%), and IL-10 (80%) above values of time-matched sham control animals. Pre-treatment with naltrexone blunted the magnitude of the increases in tissue cytokine content in response to a given blood loss. These results indicate that endogenous opiates modulate the hemodynamic instability, neuroendocrine, and cytokine responses to hemorrhagic shock.     

Heat stress and/or endotoxin effects on cytokine expression by human whole blood

Immune system cytokines induce vascular shock. Tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and bacterial endotoxin (E) circulate in human heatstroke to suggest that E release from a heat-damaged gut may stimulate cytokines that contribute to hypovolemia. However, immune activation by heat-induced tissue necrosis might stimulate cytokine generation in the absence of E. To evaluate this potential and heat stress effects on the anti-inflammatory cytokines, IL-1 receptor antagonist (IL-1ra) and IL-1 soluble receptor II (IL-1srII), a human whole blood (HWB) model was employed in which the presence or absence of E could be controlled. Using thermoelectric technology to regulate the HWB heat exposures, the temperature modulations of lethal heatstroke were precisely replicated (maximum temperature = 42.4 degrees C +/- 0.04 degrees C; thermal area = 52.3 degrees C +/- 1.5 degrees C per min). Cytokine and mRNA measurements employed enzyme-linked immunosorbant-based assay systems. Significant elevations in TNF-alpha, IL-1beta, interleukin 6 (IL-6), and IL-1ra resulted when HWB was exposed to E concentrations (10 ng/ml) reported to circulate in heatstroke. While E-stimulated IL-1ra was significantly decreased by the presence of prior heat stress (PPHS), E-stimulated IL-1beta, TNF-alpha, and IL-6 were not significantly altered by PPHS, but tended to be elevated. IL-1srII expression was unchanged by PPHS and/or E. PPHS in the absence of E did not induce cytokine responses, nor were there elevations in TNF-alpha or IL-1beta mRNA. Thus, some factor normally absent under in vitro conditions, like endotoxin, was required to provoke HWB cytokine expressions and the heat stress and E conditions that characterize heatstroke affected HWB cytokine metabolism to favor a proinflammatory environment.     

P38 MAPK mediates myocardial proinflammatory cytokine production and endotoxin-induced contractile suppression

Cardiac myocytes are capable of synthesizing tumor necrosis factor alpha (TNF-alpha), interleukin-1, and interleukin-6 (IL-1 and IL-6). p38 mitogen-activated protein kinase (MAPK) has been implicated in oxidant-stress-induced myocardial TNF-alpha production; however, the extent to which this kinase contributes to endotoxin-induced contractile dysfunction, as well as TNF-alpha, IL-1alpha, IL-1beta, and IL-6 production, in a bloodless model of endotoxin-induced myocardial dysfunction is unknown. Isolated rat hearts were perfused (Langendorff), and myocardial contractile function continuously recorded, during direct antegrade endotoxin infusion, with and without prior p38 MAPK inhibition. Ventricular p38 MAPK activation (phospho-p38 MAPK Western), cytokine mRNA (RT-PCR), and protein (ELISA) were determined. Endotoxin resulted in progressive decline in left ventricular developed pressure and coronary flow that was attenuated with prior p38 MAPK inhibition (SB 203580). p38 MAPK inhibition significantly decreased endotoxin-induced cardiac TNF-alpha, IL-1alpha, IL-1beta, and IL-6 mRNA levels. To determine the relative effect of TNF-alpha in inducing IL-1alpha, IL-1beta, and IL-6 production, TNF-alpha was sequestered during endotoxin infusion, and TNF-alpha, IL-1beta, and IL-6 protein levels were measured. Interestingly, TNF-alpha sequestration alone significantly decreased myocardial IL-1beta and IL-6 production. We conclude that p38 MAPK is involved in endotoxin-induced myocardial contractile dysfunction and myocardial TNF-alpha production; however, p38 MAPK's involvement in IL-1 and IL-6 production may be indirectly mediated by TNF-alpha.     

Interleukin 12 inhibits antigen-induced airway hyperresponsiveness, inflammation, and Th2 cytokine expression in mice

Allergic asthma is characterized by airway hyperresponsiveness and pulmonary eosinophilia, and may be mediated by T helper (Th) lymphocytes expressing a Th2 cytokine pattern. Interleukin (IL) 12 suppresses the expression of Th2 cytokines and their associated responses, including eosinophilia, serum immunoglobulin E, and mucosal mastocytosis. We have previously shown in a murine model that antigen- induced increases in airway hyperresponsiveness and pulmonary eosinophilia are CD4+ T cell dependent. We used this model to determine the ability of IL-12 to prevent antigen-induced increases in airway hyperresponsiveness, bronchoalveolar lavage (BAL) eosinophils, and lung Th2 cytokine expression. Sensitized A/J mice developed airway hyperresponsiveness and increased numbers of BAL eosinophils and other inflammatory cells after single or repeated intratracheal challenges with sheep red blood cell antigen. Pulmonary mRNA and protein levels of the Th2 cytokines IL-4 and IL-5 were increased after antigen challenge. Administration of IL-12 (1 microgram/d x 5 d) at the time of a single antigen challenge abolished the airway hyperresponsiveness and pulmonary eosinophilia and promoted an increase in interferon (IFN) gamma and decreases in IL-4 and IL-5 expression. The effects of IL-12 were partially dependent on IFN-gamma, because concurrent treatment with IL-12 and anti-IFN-gamma monoclonal antibody partially reversed the inhibition of airway hyperresponsiveness and eosinophilia by IL-12. Treatment of mice with IL-12 at the time of a second antigen challenge also prevented airway hyperresponsiveness and significantly reduced numbers of BAL inflammatory cells, reflecting the ability of IL-12 to inhibit responses associated with ongoing antigen-induced pulmonary inflammation. These data show that antigen-induced airway hyperresponsiveness and inflammation can be blocked by IL-12, which suppresses Th2 cytokine expression. Local administration of IL-12 may provide a novel immunotherapy for the treatment of pulmonary allergic disorders such as atopic asthma.     

Role of p38 mitogen-activated protein kinase in lung injury after burn trauma

This study was undertaken to evaluate the effect of SB203580, a specific p38 mitogen-activated protein (MAP) kinase inhibitor, on burn-induced lung injury as well as the release of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta in rats to characterize the role of p38 MAP kinase in lung injury after burn trauma. Sprague-Dawley rats were divided into three groups: 1) sham group, or rats who underwent sham burn; 2) control group, or rats given third-degree burns over 30% total body surface area (TBSA) and lactated Ringer solution for resuscitation; and 3) SB203580 group, or rats given burn injury and lactated Ringers solution with SB203580 inside for resuscitation. Pulmonary injury was assessed at 24 h by pulmonary capillary permeability determined with fluorescein isothiocyanate-labeled albumin and lung histologic analysis. TNF-alpha and IL-1beta protein in bronchoalveolar lavage fluid and serum were measured by enzyme-linked immunosorbent assay and p38 MAP kinase was activity determined in lung by Western blot analysis. These studies showed that significant activation of p38 MAP kinase at 24 h postburn compared with control. Burn trauma resulted in increased pulmonary capillary leakage permeability, elevated levels of TNF-alpha and IL-1beta in bronchoalveolar lavage fluid and serum, and worsened histologic condition. SB203580 inhibited the activation of p38 MAP kinase, reduced the levels of TNF-alpha and IL-1beta, and prevented burn-mediated lung injury. These data suggest that p38 MAP kinase activation is one important aspect of the signaling event that may mediate the release of TNF-alpha and IL-1beta and contributes to burn-induced lung injury.     

Transient expression of IL-1β induces acute lung injury and chronic repair leading to pulmonary fibrosis

IL-1beta is one of a family of proinflammatory cytokines thought to be involved in many acute and chronic diseases. Although it is considered to participate in wound repair, no major role has been attributed to IL-1beta in tissue fibrosis. We used adenoviral gene transfer to transiently overexpress IL-1beta in rat lungs after intratracheal administration. The high expression of IL-1beta in the first week after injection was accompanied by local increase of the proinflammatory cytokines IL-6 and TNF-alpha and a vigorous acute inflammatory tissue response with evidence of tissue injury. The profibrotic cytokines PDGF and TGF-beta1 were increased in lung fluid samples 1 week after peak expression of IL-1beta. Although PDGF returned to baseline in the third week, TGF-beta1 showed increased concentrations in bronchoalveolar lavage fluid for up to 60 days. This was associated with severe progressive tissue fibrosis in the lung, as shown by the presence of myofibroblasts, fibroblast foci, and significant extracellular accumulations of collagen and fibronectin. These data directly demonstrate how acute tissue injury in the lung, initiated by a highly proinflammatory cytokine, IL-1beta, converts to progressive fibrotic changes. IL-1beta should be considered a valid target for therapeutic intervention in diseases associated with fibrosis and tissue remodeling.     

Minocycline attenuates mechanical allodynia and proinflammatory cytokine expression in rat models of pain facilitation

Activated glial cells (microglia and astroglia) in the spinal cord play a major role in mediating enhanced pain states by releasing proinflammatory cytokines and other substances thought to facilitate pain transmission. In the present study, we report that intrathecal administration of minocycline, a selective inhibitor of microglial cell activation, inhibits low threshold mechanical allodynia, as measured by the von Frey test, in two models of pain facilitation. In a rat model of neuropathic pain induced by sciatic nerve inflammation (sciatic inflammatory neuropathy, SIN), minocycline delayed the induction of allodynia in both acute and persistent paradigms. Moreover, minocycline was able to attenuate established SIN-induced allodynia 1 day, but not 1 week later, suggesting a limited role of microglial activation in more perseverative pain states. Our data are consistent with a crucial role for microglial cells in initiating, rather than maintaining, enhanced pain responses. In a model of spinal immune activation by intrathecal HIV-1 gp120, we show that the anti-allodynic effects of minocycline are associated with decreased microglial activation, attenuated mRNA expression of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-1beta-converting enzyme, TNF-alpha-converting enzyme, IL-1 receptor antagonist and IL-10 in lumbar dorsal spinal cord, and reduced IL-1beta and TNF-alpha levels in the CSF. In contrast, no significant effects of minocycline were observed on gp120-induced IL-6 and cyclooxygenase-2 expression in spinal cord or CSF IL-6 levels. Taken together these data highlight the importance of microglial activation in the development of exaggerated pain states.     

Ginger extract inhibits beta-amyloid peptide-induced cytokine and chemokine expression in cultured THP-1 monocytes

INTRODUCTION: Neuritic plaques, a neuropathologic hallmark of Alzheimer's disease, are extracellular deposits of beta-amyloid peptides (Abeta). In the central nervous system neuritic plaques are surrounded by activated microglial cells expressing proinflammatory cytokines, chemokines, and neurotoxic mediators. Long-term activation of microglial cells is suspected to contribute to the neuron loss in Alzheimer's disease. OBJECTIVE: This study was conducted to determine whether a ginger (Zingiber officinale and Alpinia galanga) extract (GE) can dampen the activation of THP-1 cells by lipopolysaccharide, proinflammatory cytokines, and fibrillar amyloid peptide Abeta(1-42), a major component of neuritic plaques. METHODS: THP-1 cells, a human monocytic cell line with properties similar to human microglial cells, were incubated with GE or control medium alone for 1 hour, and then with reincubated lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) or fibrillar Abeta(1-42) for an additional hour. The extent of THP-1 cell activation was determined by measuring mRNA levels of TNF-alpha and IL-1beta, cyclooxygenase-2 (COX-2), macrophage inflammatory protein 1alpha (MIP-1alpha), monocyte chemoattractant protein-1 (MCP-1), and interferon-gamma inducible protein 10 (IP-10). RESULTS: The results document that the GE used in this study inhibits LPS, cytokine, and amyloid Abeta peptide-induced expression of the proinflammatory genes TNF-alpha, IL-1beta, COX-2, MIP-alpha, MCP-1, and IP-10. The data provide experimental evidence that ginger can inhibit the activation of human monocytic THP-1 cells by different proinflammatory stimuli and reduce the expression of a wide range of inflammation-related genes in these microglial-like cells. CONCLUSIONS: The findings suggest that GE may be useful in delaying the onset and the progression of neurodegenerative disorders involving chronically activated microglial cells in the central nervous system.     

Ligation of protease-activated receptor 1 enhances alpha(v)beta6 integrin-dependent TGF-beta activation and promotes acute lung injury

Activation of latent TGF-beta by the alpha(v)beta6 integrin is a critical step in the development of acute lung injury. However, the mechanism by which alpha(v)beta6-mediated TGF-beta activation is regulated has not been identified. We show that thrombin, and other agonists of protease-activated receptor 1 (PAR1), activate TGF-beta in an alpha(v)beta6 integrin-specific manner. This effect is PAR1 specific and is mediated by RhoA and Rho kinase. Intratracheal instillation of the PAR1-specific peptide TFLLRN increases lung edema during high-tidal-volume ventilation, and this effect is completely inhibited by a blocking antibody against the alpha(v)beta6 integrin. Instillation of TFLLRN during high-tidal-volume ventilation is associated with increased pulmonary TGF-beta activation; however, this is not observed in Itgb6-/- mice. Furthermore, Itgb6-/- mice are also protected from ventilator-induced lung edema. We also demonstrate that pulmonary edema and TGF-beta activity are similarly reduced in Par1-/- mice following bleomycin-induced lung injury. These results suggest that PAR1-mediated enhancement of alpha(v)beta6-dependent TGF-beta activation could be one mechanism by which activation of the coagulation cascade contributes to the development of acute lung injury, and they identify PAR1 and the alpha(v)beta6 integrin as potential therapeutic targets in this condition.     

Patterns of cytokine release and evolution of remote organ dysfunction after bilateral femur fracture

The interaction between the complex pattern of cytokine release and remote organ dysfunction after trauma is incompletely understood. The aim of this study was to investigate the pattern of cytokine release and its association with the evolution of remote organ dysfunction after bilateral femur fracture. Male C57/BL6 mice were euthanized at six different time points (1-6 h) after bilateral femur fracture. Serum cytokine concentrations were measured with the Luminex multiplexing platform, and serum alanine aminotransferase levels were measured with the Vitros 950 Chemistry System. Hepatic and pulmonary myeloperoxidase activity was determined with an enzyme-linked immunosorbent assay kit. Permeability changes of the lung were assessed via bronchoalveolar lavage, and those of the liver via assessment of edema formation. Serum TNF-alpha was unchanged in the fracture group throughout the experiment. Serum IL-6 and keratinocyte levels peaked at 5 h postinjury, whereas IL-10 levels peaked at 2 and 6 h. A brief IL-1beta peak was observed at 3 h after fracture. Hepatic and pulmonary myeloperoxidase activity was significantly elevated within 1 h after trauma. Hepatic permeability was significantly increased within 2 h, and pulmonary permeability was significantly increased within 6 h after injury. Serum alanine aminotransferase levels peaked at 3 and 5 h postinjury. The pattern of serum IL-6, keratinocyte, IL-10, and IL-1beta release was dynamic, whereas no significant elevations in TNF-alpha were observed. The early hepatic and pulmonary infiltration of polymorphonuclear cells occurred in the absence of significantly elevated serum cytokine levels, suggesting that either early minor changes with an unbalance in inflammatory mediators or locally produced cytokines may initiate this process.     

内毒素致伤大鼠肺组织促炎与抗炎细胞因子mRNA表达的时相性研究

目的 研究不同剂量内毒素致伤大鼠肺组织促炎和抗炎细胞因子mRNA表达的时相性,并探讨这些细胞因子在全身炎症反应失控和急性肺损伤中的可能作用。方法 采用逆转录-聚合酶链反应(RT-PCR)检测不同剂量脂多糖(LPS)致伤大鼠肺组织肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1β、IL-6、IL-4、IL-10和IL-13的mRNA表达。结果 随着LPS剂量增加,TNF-α、IL-1β、IL-6、IL-4、IL-10和IL-13的mRNA表达均增强(与生理盐水对照组比较,P均<0.01);LPS≥6 mg/kg组上述细胞因子表达显著高于此剂量以下组(P均<0.01)。表达峰值时间:TNF-α为1 h,IL-6为4 h,其他均在2 h。结论 内毒素致急性肺损伤中,TNF-α是早期表达的促炎细胞因子,而IL-6在炎症进一步发展中发挥作用;抗炎细胞因子IL-4、IL-10、IL-13高表达亦可能促进炎症的放大而不是起保护作用。     

Endotoxin stimulates in vivo expression of inflammatory cytokines tumor necrosis factor alpha,interleukin-1beta, -6, and high-mobility-group protein-1 in skeletal muscle

The presence of increased levels of proinflammatory cytokines in the blood is associated with decreased muscle protein synthesis and the erosion of lean body mass in many catabolic conditions. However, little is known regarding the role of endogenous cytokine synthesis in muscle per se. The purpose of the present study was to characterize the cytokine expression profile of skeletal muscle in response to an in vivo injection of endotoxin (lipopolysaccharide, LPS). Intraperitoneal injection of a nonlethal dose of LPS (1,000 microg/kg Escherichia coli) into male rats increased the mRNA content of tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta in gastrocnemius muscle as early as 1 h; IL-6 mRNA was not increased until 2 h post-LPS. Expression of TNF-alpha and IL-1beta peaked at 2 h (10- and 80-fold, respectively), whereas the increased IL-6 mRNA content (150-fold) peaked later at 4 h. The abundance of all measured cytokine mRNAs in skeletal muscle declined thereafter. The LPS-induced increase in muscle mRNA content for TNF-alpha, IL-6, and IL-1beta was dose-dependent with elevations being seen with as little as 10 microg/kg of LPS (2.5-, 8-, and 9-fold, respectively). In general, pretreatment of rats with dexamethasone attenuated but did not completely prevent the LPS-induced increase in muscle cytokine mRNA. LPS increased muscle TNF-alpha protein content approximately 2-fold and this increase was prevented by pretreatment with dexamethasone. LPS-induced increases in muscle IL-1beta and IL-6 protein were not detected. LPS also produced a 2-fold increase in the mRNA content of the high-mobility-group protein-1, a late-phase cytokine, in muscle at 12-24 h. Finally, although skeletal muscle was found to contain both the toll-like receptor (TLR)-2 and TLR4, LPS did not alter the mRNA content of TLR4 and produced a small (50%) but significant increase in TLR2 mRNA. These changes in TLRs were less dramatic than those observed for liver, spleen or cardiac muscle. Collectively these data indicate that skeletal muscle possesses many of the components of the innate immune system, including increases in both early- and late-phase cytokines and the presence of toll-like receptors.     

Cervical and vaginal cytokine determinations in pregnant women: methodologic issues

Investigations of the role cytokines play in preterm birth are complicated by a number of methodologic issues that arise as to the most feasible and efficient methods to measure cytokines. The purpose of this article is to review methodologic issues surrounding the measurement of vaginal and cervical cytokines, specifically IL-1beta, IL-6, and TNF-alpha, in pregnant women experiencing preterm labor. Specifically, two quantification methods, weight and protein assay, and cytokine specimens from two different sites, vaginal and cervical, were compared. There were no significant correlations between cytokine levels using the protein versus weight quantification method. The weight method had more negative values and thus the protein quantification method was more accurate. There were high correlations between cervical and vaginal IL-1beta levels and IL-6 levels, but cervical and vaginal TNF-alpha levels were not correlated.     

Ghrelin inhibits leptin- and activation-induced proinflammatory cytokine expression by human monocytes and T cells

Ghrelin, a recently described endogenous ligand for the growth hormone secretagogue receptor (GHS-R), is produced by stomach cells and is a potent circulating orexigen, controlling energy expenditure, adiposity, and growth hormone secretion. However, the functional role of ghrelin in regulation of immune responses remains undefined. Here we report that GHS-R and ghrelin are expressed in human T lymphocytes and monocytes, where ghrelin acts via GHS-R to specifically inhibit the expression of proinflammatory anorectic cytokines such as IL-1beta, IL-6, and TNF-alpha. Ghrelin led to a dose-dependent inhibition of leptin-induced cytokine expression, while leptin upregulated GHS-R expression on human T lymphocytes. These data suggest the existence of a reciprocal regulatory network by which ghrelin and leptin control immune cell activation and inflammation. Moreover, ghrelin also exerts potent anti-inflammatory effects and attenuates endotoxin-induced anorexia in a murine endotoxemia model. We believe this to be the first report demonstrating that ghrelin functions as a key signal, coupling the metabolic axis to the immune system, and supporting the potential use of ghrelin and GHS-R agonists in the management of disease-associated cachexia.