Distinct functions of interferon-gamma for chemokine expression in models of acute lung inflammation

Challenge of the immune system with bacterial superantigens or endotoxin induces the systemic release of cytokines followed by lethal septic shock. The lung is particularly susceptible to systemic toxin exposure resulting in acute leucocyte infiltration and vascular damage. In the present study, the functions of interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) for chemokine regulation during acute lung inflammation were examined. Following administration of the superantigen, staphylococcal enterotoxin B (SEB), lung mRNA levels of the chemokines cytokine-induced neutrophil chemo-attractant (KC), lipopolysaccharide-induced CXC chemokine (LIX), macrophage chemotactic protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1alpha and MIP-2 were increased to a similar extent both in controls and in mice deficient for the IFN-gamma or 55 000 MW TNF receptors. In contrast, interferon-inducible protein-10 (IP-10) and monokine induced by IFN-gamma (Mig) mRNA expression was markedly reduced in mice deficient for IFN-gamma or IFN-gamma receptor, but not in 55 000 MW TNF receptor knockout mice. In situ hybridization experiments demonstrated that IP-10 was highly expressed in lung interstitial macrophages of C57BL/6, but not of IFN-gamma receptor-deficient mice. In contrast to SEB administration, treatment with lipopolysaccharide resulted in a strong induction of IP-10 and Mig in IFN-gamma receptor-deficient mice. Together, these results establish a critical function of IFN-gamma for chemokine induction in acute lung inflammation that is dependent on the nature of the inflammatory stimulus.

Essential role of gamma interferon in survival of colon ascendens stent peritonitis, a novel murine model of abdominal sepsis

Despite considerable progress, peritonitis and sepsis remain life-threatening conditions. To improve the understanding of the pathophysiology encountered in sepsis, a new standardized and highly reproducible murine model of abdominal sepsis termed colon ascendens stent peritonitis (CASP) was developed. In CASP, a stent is inserted into the ascending colon, which generates a septic focus. CASP employing a stent of 14-gauge diameter (14G stent) results in a mortality of 100% within 18 to 48 h after surgery. By inserting stents of small diameters, mortality can be exactly controlled. Thus, CASP surgery with insertion of a 22G or 18G stent (22G or 18G CASP surgery) results in 38 or 68% mortality, respectively. 14G CASP surgery leads to a rapid invasion of bacteria into the peritoneum and the blood. As a consequence, endotoxemia occurs, inflammatory cells are recruited, and a systemic inflammatory response syndrome develops. Interestingly, the most pronounced upregulation of inflammatory cytokines (gamma interferon [IFN-gamma], tumor necrosis factor alpha [TNF-alpha] and interleukin-12) is observed in spleen and lungs. CASP surgery followed by stent removal at specific time intervals revealed that all animals survived if intervention was performed after 3 h, whereas removal of the septic focus after 9 h did not prevent death, suggesting induction of autonomous mechanisms of a lethal inflammatory response syndrome. 18G CASP surgery in IFN-gamma receptor-deficient (IFNgammaR-/-) mice revealed an essential role of IFN-gamma in survival of sepsis, whereas TNF receptor p55-deficient (TNFRp55-/-) mice did not show altered survival rates. In summary, this study describes a novel animal model that closely mimics human sepsis and appears to be highly suitable for the study of the pathophysiology of abdominal sepsis. Importantly, this model demonstrates a protective role of IFN-gamma in survival of bacterial sepsis.

Modulation of the activation status of Stat5a during LIF-induced differentiation of M1 myeloid leukemia cells

Treatment of M1 myeloid leukemia cells with leukemia inhibitory factor (LIF) causes activation of transcription factors Stat1, Stat3 and Stat5a (signal transducers and activators of transcription). DNA-binding of Stat proteins was detectable for extended periods of time in LIF-treated M1 cells, which simultaneously underwent terminal differentiation. The relative composition of Stat factors in the protein-DNA complexes changed during time. Whereas Stat3 was activated up to 36 h during treatment with LIF, Stat5a was activated only short-termed. Similarly, high expression of the immediate early gene CIS (cytokine-inducible SH2-containing protein), a known target gene of Stat5 in hematopoietic cells, occurred only during the onset of differentiation. This suggests a role of Stat5a in the early phase of LIF-induced differentiation and growth arrest of M1 cells.

Physical activity and fitness in patients with headache disorders

Recent studies indicate that aerobic activities might reduce severity and/or frequency of migraine attacks. The present study was intended to investigate whether physical activities and fitness (aerobic endurance, flexibility, and muscle strength endurance) as well as body composition are different in patients with headache disorders and healthy control subjects. The study included 56 patients (aged 17-64 years) with headache disorders (migraine, tension-type, cluster, analgetics abuse, and other types of headache) and 145 age-matched volunteers without history of recurrent or chronic headache. A standardized questionnaire revealed similar self-esteem of physical activities in both groups. Objective physical fitness testing in a representative sample of 22 patients and 36 control subjects showed significantly reduced aerobic endurance in female and male patients as well as reduced flexibility in female patients as compared to control subjects, whereas muscle strength endurance was not significantly different between both groups. Female patients presented with a significantly higher total body fat as compared to control subjects. In conclusion, headache patients turned out to be less physically fit than control subjects. There was a discrepancy between self-esteem and objective test results regarding physical activity and fitness in patients with headache disorders.

Induction of acute inflammatory lung injury by staphylococcal enterotoxin B

Superantigens stimulate T lymphocytes at high frequency by interacting with appropriate Vbeta segments of the TCR. Challenge of mice with bacterial superantigens such as staphylococcal enterotoxin B (SEB) induces the systemic release of cytokines resulting in septic shock and death of sensitized animals. Analysis of putative pathogenic mechanisms of T cell-dependent septic shock revealed that administration of SEB results in acute inflammatory lung injury characterized by a profound increase in vascular permeability. Injury was associated with marked leukocyte infiltration of the lung and induction of cell adhesion molecules including VCAM-1, ICAM-1, and P-selectin, but not E-selectin. Lung infiltrating leukocytes consisted of granulocytes, mononuclear phagocytes and NK cells with granulocytes representing the major fraction. Consistent with a role of neutrophils as cellular mediators of inflammatory organ injury, we demonstrate activation of circulating granulocytes in mice treated with SEB. When compared with granulocytes of control mice, peripheral blood granulocytes of SEB-treated mice were found to express increased levels of cell surface Mac-1, to down-regulate expression of L-selectin, and to respond with an increased production of toxic oxygen metabolites upon exposure to FMLP. Interestingly, TNF-alpha further enhanced FMLP-induced oxidant production by granulocytes from SEB-treated but not control mice, suggesting that the systemic response to SEB increases granulocyte sensitivity to TNF-alpha-mediated signals. Together, these results suggest that acute inflammatory lung injury may contribute to the pathogenesis of T cell-dependent lethal shock in mice challenged with bacterial superantigens and indicate common pathogenic mechanisms of lung injury induced by a large number of distinct inflammatory stimuli.

Induction of acute inflammatory lung injury by staphylococcal enterotoxin B

Superantigens stimulate T lymphocytes at high frequency by interacting with appropriate Vbeta segments of the TCR. Challenge of mice with bacterial superantigens such as staphylococcal enterotoxin B (SEB) induces the systemic release of cytokines resulting in septic shock and death of sensitized animals. Analysis of putative pathogenic mechanisms of T cell-dependent septic shock revealed that administration of SEB results in acute inflammatory lung injury characterized by a profound increase in vascular permeability. Injury was associated with marked leukocyte infiltration of the lung and induction of cell adhesion molecules including VCAM-1, ICAM-1, and P-selectin, but not E-selectin. Lung infiltrating leukocytes consisted of granulocytes, mononuclear phagocytes and NK cells with granulocytes representing the major fraction. Consistent with a role of neutrophils as cellular mediators of inflammatory organ injury, we demonstrate activation of circulating granulocytes in mice treated with SEB. When compared with granulocytes of control mice, peripheral blood granulocytes of SEB-treated mice were found to express increased levels of cell surface Mac-1, to down-regulate expression of L-selectin, and to respond with an increased production of toxic oxygen metabolites upon exposure to FMLP. Interestingly, TNF-alpha further enhanced FMLP-induced oxidant production by granulocytes from SEB-treated but not control mice, suggesting that the systemic response to SEB increases granulocyte sensitivity to TNF-alpha-mediated signals. Together, these results suggest that acute inflammatory lung injury may contribute to the pathogenesis of T cell-dependent lethal shock in mice challenged with bacterial superantigens and indicate common pathogenic mechanisms of lung injury induced by a large number of distinct inflammatory stimuli.

Stigmatella aurantiaca fruiting body formation is dependent on the fbfA gene encoding a polypeptide homologous to chitin synthases

Stigmatella aurantiaca is a prokaryotic organism that undergoes a multicellular cycle of development resulting in the formation of a fruiting body. For analyzing this process, mutants defective in fruiting body formation have been induced by transposon mutagenesis using a Tn5-derived transposon. About 800 bp upstream of the transposon insertion of mutant AP182 which inactivates a gene (fbfB) involved in fruiting, a further gene (fbfA) needed for fruiting body formation was detected. Inactivation of fbfA leads to mutants which form only non-structured clumps instead of the wild-type fruiting body. The mutant phenotype of fbfA mutants can be partially suppressed by mixing the mutant cells with cells of some independent mutants defective in fruiting body formation. The fbfA gene is transcribed after 8 h of development as determined by measuring the induction of beta-galactosidase activity of a fbfA-delta(trp)-lacZ fusion gene and by Northern (RNA) analysis using an insertion encoding a stable mRNA. The predicted polypeptide FbfA shows a homology of about 30% to NodC of rhizobia, an N-acetylglucosamine-transferase which is involved in the synthesis of the sugar backbone of lipo-oligosaccharides. These induce the formation of the root nodules in the Papilionaceae. Besides the predicted molecular mass of 45.5 kDa, the hydropathy profile reveals a structural relationship to the NodC polypeptide.

Function of the p55 tumor necrosis factor receptor "death domain" mediated by phosphatidylcholine-specific phospholipase C

Tumor necrosis factor (TNF) is a pleiotropic mediator of inflammation that has been implicated in the pathogenesis of devastating clinical syndromes including septic shock. We have investigated the role of a TNF-responsive phosphatidylcholine-specific phospholipase C (PC-PLC) for the cytotoxic and proinflammatory activity of TNF. We show here that the cytotoxicity signaled for by the so-called "death domain" of the p55 TNF receptor is associated with the activation of PC-PLC. The xanthogenate tricyclodecan-9-yl (D609), a specific and selective inhibitor of PC-PLC, blocked the cytotoxic action of TNF on L929 and Wehi164 cells. In vivo, D609 prevented both adhesion molecule expression in the pulmonary vasculature and the accompanying leukocyte infiltration in TNF-treated mice. More strikingly, D609 protects BALB/c mice from lethal shock induced either by TNF, lipopolysaccharide, or staphylococcal enterotoxin B. Together these findings imply PC-PLC as an important mediator of the pathogenic action of TNF, suggesting that PC-PLC may serve as a novel target for anti-inflammatory TNF antagonists.

Defective Peyer's patch organogenesis in mice lacking the 55-kD receptor for tumor necrosis factor

Lymphotoxin alpha (LT-alpha) may form secreted homotrimers binding to p55 and p75 tumor necrosis factor (TNF) receptors or cell surface-bound heterotrimers with LT-beta that interact with the LT-beta receptor. Genetic ablation of LT-alpha revealed that mutant mice have no detectable lymph nodes or Peyer's patches and that the organization of the splenic white pulp in T and B cell areas is disturbed. In this report we describe a novel function for the p55 TNF receptor during ontogeny and demonstrate that mice deficient for p55 completely lack organized Peyer's patches. In contrast, lymph nodes and spleen are present in p55-deficient mice and lymphocytes segregate normally into B and T cell areas in these organs. Lamina propria and intraepithelial lymphocytes of the small intestine were detected in normal number and distribution in p55 mutant mice. Lymphocytes and endothelial cells from p55-deficient mice express normal levels of adhesion molecules considered important for lymphocyte migration to mucosal organs; this indicates that the lack of Peyer's patches does not result from a defect in lymphocyte homing. In summary, the p55 receptor for TNF selectively mediates organogenesis of Peyer's patches throughout ontogeny, suggesting that the effects of LT-alpha on the development of lymphoid organs may be mediated by distinct receptors, each functioning in an organ-specific context.

A serine-kinase associated with the p127-l(2)gl tumour suppressor of Drosophila may regulate the binding of p127 to nonmuscle myosin II heavy chain and the attachment of p127 to the plasma membrane

The p127 tumour suppressor protein encoded by the lethal(2)giant larvae, [l(2)gl], gene of Drosophila melanogaster is a component of a cytoskeletal network distributed in both the cytoplasm and on the inner face of the plasma membrane. The p127 protein forms high molecular mass complexes consisting mainly of homo-oligomerized p127 molecules and at least ten additional proteins. One of these proteins has been recently identified as nonmuscle myosin type II heavy chain. To determine the functional interactions between p127 and other proteins present in the p127 complexes, we analyzed p127 for posttranslational modifications and found that p127 can be phosphorylated at serine residues. In this report we describe the characteristics of a serine kinase which is associated with p127, as judged by its recovery in p127 complexes purified by either gel filtration or immuno-affinity chromatography. This kinase phosphorylates p127 in vitro and its activation by supplementing ATP results in the release of p127 from the plasma membrane. Moreover, similar activation of the kinase present in immuno-purified p127 complexes dissociates nonmuscle myosin II from p127 without affecting the homo-oligomerization of p127. This dissociation can be inhibited by staurosporine and a 26mer peptide covering amino acid positions 651 to 676 of p127 and containing five serine residues which are evolutionarily conserved from Drosophila to humans. These results indicate that a serine-kinase tightly associated with p127 regulates p127 binding with components of the cytoskeleton present in both the cytoplasm and on the plasma membrane.

Multiple roles for DNA methylation in gametic imprinting

Allele-specific DNA methylation has been observed for all tested imprinted genes and has a clear role in the imprinting mechanism. It remains to be resolved whether this role is to act as the gametic imprinting signal or to cause or maintain allele-specific expression.

Oxygen Abstraction Reactions of N-Substituted Hydroxamic Acids with Molybdenum(V) and Vanadium(III) and -(IV) Compounds

A wide range of N-substituted mono- and dihydroxamic acids undergo oxygen abstraction on reaction with V(III), V(IV), and Mo(V) compounds to form hydroxamates of V(V) and Mo(VI) respectively together with the corresponding amides and diamides. The molybdenyl and vanadyl hydroxamates form metal-oxygen clusters under FABMS conditions. The X-ray crystal structures of [MoO(2){CH(3)(CH(2))(n)()C(O)N(C(6)H(5))O}(2) (1 and 2) (n = 4, 5) show monomeric structures with structural trans effects and consequent weakening of the Mo-O(ligand) bonds which may account for the tendency to form clusters in FABMS. In constrast, the electrospray MS of the vanadyl dihydroxamates, VO(OH)[PhN(O)C(O)(CH(2))(n)()C(O)N(O)Ph] (n = 3, 5) and VO(OH)[p-CH(3)C(6)H(4)N(O)C(O) (CH(2))(n)()C(O)N(O)C(6)H(4)-CH(3)) (n = 2, 4) show the presence of dimers in solution.

Crucial role of 55-kilodalton TNF receptor in TNF-induced adhesion molecule expression and leukocyte organ infiltration

Stimulation of leukocyte adhesion to the endothelium by TNF is mediated by the up-regulation of adhesion molecules on the endothelial cell surface. C57BL/6 mice and syngenic 55-kDa TNF receptor-deficient mice (TNFRp55-/- mice) were challenged with TNF, and the kinetics of intracellular adhesion molecule-1, ICAM-1, mucosal addressin cell adhesion molecule-1, vascular adhesion molecule-1 (VCAM-1), and E-selectin expression were examined in various organs. TNF induced sustained VCAM-1 expression within 4 h in lung, liver, and kidney. In the lungs, but not in other organs, transient E-selectin expression was induced by TNF within 0.5 h and peaked at 4 h. The TNF-induced expression of VCAM-1 and E-selectin was found to be exclusively controlled by the 55-kDa TNF-receptor (TNFRp55) as demonstrated by analysis of TNFRp55-/- mice. Furthermore, TNF triggered mononuclear cell and neutrophil infiltration of lung, liver, and kidney in C57BL/6 mice but not TNFRp55-/- mice. Interestingly, MAdCAM-1 expression in the marginal sinus of the spleen was detected in wild-type mice but was absent in TNFRp55-/- mice. Together, the data suggest that in vivo the 55-kDa TNF receptor mediates the induction of VCAM-1 and E-selectin expression and is critically involved in the control of leukocyte organ infiltration.

Crucial role of 55-kilodalton TNF receptor in TNF-induced adhesion molecule expression and leukocyte organ infiltration

Stimulation of leukocyte adhesion to the endothelium by TNF is mediated by the up-regulation of adhesion molecules on the endothelial cell surface. C57BL/6 mice and syngenic 55-kDa TNF receptor-deficient mice (TNFRp55-/- mice) were challenged with TNF, and the kinetics of intracellular adhesion molecule-1, ICAM-1, mucosal addressin cell adhesion molecule-1, vascular adhesion molecule-1 (VCAM-1), and E-selectin expression were examined in various organs. TNF induced sustained VCAM-1 expression within 4 h in lung, liver, and kidney. In the lungs, but not in other organs, transient E-selectin expression was induced by TNF within 0.5 h and peaked at 4 h. The TNF-induced expression of VCAM-1 and E-selectin was found to be exclusively controlled by the 55-kDa TNF-receptor (TNFRp55) as demonstrated by analysis of TNFRp55-/- mice. Furthermore, TNF triggered mononuclear cell and neutrophil infiltration of lung, liver, and kidney in C57BL/6 mice but not TNFRp55-/- mice. Interestingly, MAdCAM-1 expression in the marginal sinus of the spleen was detected in wild-type mice but was absent in TNFRp55-/- mice. Together, the data suggest that in vivo the 55-kDa TNF receptor mediates the induction of VCAM-1 and E-selectin expression and is critically involved in the control of leukocyte organ infiltration.

A human homologue of the Drosophila tumour suppressor gene l(2)gl maps to 17p11.2-12 and codes for a cytoskeletal protein that associates with nonmuscle myosin II heavy chain

Inactivation of the tumour suppressor gene lethal(2) giant larvae (D-lgl) of Drosophila leads to malignant transformation of the presumptive adult optic centers in the larval brain and tumours of the imaginal discs. These malignancies result from the disorganization of a cytoskeletal network in which the D-LGL protein participates. Here we describe the isolation of a cDNA encoding the human homologue to the D-lgl gene designated as hugl. The hugl cDNA detects a locus spanning at least 25 kilobases (kb) in human chromosome band 17p11.2-12, which is centromeric to the p53 gene and recognizes a 4.5 kb RNA transcript. The hugl gene is expressed in brain, kidney and muscle but is barely seen in heart and placenta. Sequence analysis of the hugl cDNA demonstrates a long open reading frame, which has the potential to encode a protein of 1057 amino acids with a predicted molecular weight of 115 kDaltons (kD). To further substantiate and identify the HUGL protein, we have prepared polyclonal rabbit antibodies against synthetic peptides corresponding to the amino and carboxyl termini of the conceptual translation product of the hugl gene. The affinity-purified anti-HUGL antibodies recognize a single protein with an apparent molecular weight of approximately 115 kD. Similar to the Drosophila protein, HUGL is part of a cytoskeletal network and, is associated with nonmuscle myosin II heavy chain and a kinase that specifically phosphorylates HUGL at serine residues.

Effects of stress on drug-induced yawning: constant vs. intermittent stress

Effects of stress on drug-induced yawning: Constant vs. intermittent stress. PHYSIOL BEHAV 58(1) 181-184, 1995.--Experiment 1 tested whether chronic exposure to immobilization, foot shock or forced swimming would result in suppression of apomorphine-, pilocarpine-, and physostigmine-induced yawning. Immobilization caused suppression of yawning, whereas foot shock and swimming resulted in increased number of yawns. Since interstressor interval was long in the two latter stressors, animals could have recovered and the increase in yawning could be due to the last (acute) exposure to stress. In Experiment 2 we recorded the number of yawns induced by pilocarpine in animals exposed to 1 h of swimming or foot shock. No differences between control and acutely stressed animals were detected. These results suggest that yawning is differently altered by constant and intermittent stressors (i.e., diminished by constant and increased by intermittent stress).