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ABSTRACT: A number of lung diseases, including many interstitial lung diseases and HIV infection, are associated with decreases in intracellular thiols. Altered Th1/Th2 T cell balance has also been associated with disease progression in many of the same diseases. IFN-gamma and IL-4 are critical effector cytokines of Th1 and Th2 cells, respectively. To determine the effect of thiols on the production of IFN-gamma and IL-4 by splenocytes, cells were incubated in the presence and the absence of N-acetylcysteine (NAC) and stimulated with alphaCD3 or alphaCD3 and IL-12. Augmenting intracellular soluble thiol pools ( approximately 2-fold) with 15 mM NAC blocked induction of IFN-gamma and increased production of IL-4 without causing significant changes in intracellular glutathione levels. The effect of NAC on IL-4 production was not linked to an increase in STAT6 phosphorylation, as STAT6 levels were decreased, nor did the increase in IL-4 occur with purified CD4 cells. We found that NAC increased splenocyte IL-4 production via an effect on APCs. We also found that NAC increased two IL-4 relevant transcription factors (AP-1) and NFATc. These studies suggest that increasing intracellular reduced thiol pools decreases IL-12 signaling and IFN-gamma production, while increasing IL-4 production. The sum of these effects may contribute to alterations in the balance between Th1 and Th2 responses in lung diseases associated alterations in intracellular thiol pools.
The Journal of Immunology 12/2003; 171(10):5107-15. · 5.79 Impact Factor
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Gary W Hunninghake,
David A Lynch,
Jeffrey R Galvin,
Barry H Gross,
Nestor Müller,
David A Schwartz,
Talmadge E King,
Joseph P Lynch,
Richard Hegele,
James Waldron,
Thomas V Colby,
James C Hogg
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ABSTRACT: To determine which clinical and radiologic findings are independently associated with a pathologic diagnosis of usual interstitial pneumonia (UIP).
We recently reported, using a prospective, multicenter study of patients suspected of having idiopathic interstitial pneumonia (IIP), that a confident diagnosis of UIP made by experienced radiologists was correct in 95% of cases. In the current article, we further analyzed data from this study. Ninety-one patients were entered into the study. Clinical, physiologic, chest radiographic, and CT features were prospectively recorded, and analyzed using univariate and multivariate logistic regression analysis to compare the patients with a histologic diagnosis of UIP with those who received other pathologic diagnoses.
Fifty-four of 91 patients (59%) received a pathologic diagnosis of UIP. The following features recorded at the referring clinical centers were associated with a pathologic diagnosis of UIP on multivariate analysis: lower-lobe honeycombing on high-resolution CT (HRCT) [odds ratio, 11.45], radiographic findings consistent with UIP (odds ratio, 5.73), elevated ratio of FEV(1) to FVC (odds ratio, 4.8), and absence of smoking history (odds ratio, 0.19). On multivariate analysis of specific HRCT features recorded by four experienced chest radiologists, lower-lung honeycombing (odds ratio, 5.36) and upper-lung irregular lines (odds ratio, 6.28) were the only independent predictors of UIP. Using only these two factors, a diagnosis of UIP could be established with a sensitivity of 74%, a specificity of 81%, and a positive predictive value of 85%.
In patients presenting with a clinical syndrome suggestive of IIP, CT findings of lower-lung honeycombing and upper-lung irregular lines are most closely associated with a pathologic diagnosis of UIP.
Chest 11/2003; 124(4):1215-23. · 5.25 Impact Factor
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ABSTRACT: Effects of adenoviral infection on in vivo responses to LPS mediated by TNF-alpha were evaluated in a murine model. Adenovirus-infected mice showed decreased mortality from fulminant hepatitis induced by administration of LPS or staphylococcal enterotoxin B in the presence of D-galactosamine. Importantly, TNF-alpha resistance genes within adenoviral E3 region were not required, because E1,E3-deleted vectors showed similar effects. Adenovirus-infected mice exhibited higher TNF-alpha levels after LPS stimulation, no difference in TNFR1 expression, and similar mortality from Fas-induced fulminant hepatitis. Decreased production of IL-6 and KC in response to exogenous TNF-alpha, in addition to protection from TNF-alpha, suggested that adenoviral infection results in TNF-alpha tolerance.
The Journal of Immunology 10/2003; 171(5):2453-60. · 5.79 Impact Factor
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ABSTRACT: These studies demonstrate that treatment of macrophages with lovastatin, a cholesterol-lowering drug that blocks farnesylation and geranylgeranylation of target proteins, increases LPS-induced TNF-alpha production. This is reversed by the addition of mevalonate, which bypasses the lovastatin block. Examination of membrane localization of RhoA, Cdc42, Rac1, and Ras demonstrated decreased membrane localization of the geranylgeranylated Rho family members (RhoA, Cdc42, and Rac1) with no change in the membrane localization of farnesylated Ras. LPS-induced TNF-alpha production in the presence of the Rho family-specific blocker (toxin B from Clostridium difficile) was significantly enhanced consistent with the lovastatin data. One intracellular signaling pathway that is required for TNF-alpha production by LPS is the extracellular signal-regulated kinase (ERK). Significantly, we found prolonged ERK activation after LPS stimulation of lovastatin-treated macrophages. When we inhibited ERK, we blocked the lovastatin-induced increase in TNF-alpha production. As a composite, these studies demonstrate a negative role for one or more Rho family GTPases in LPS-induced TNF-alpha production.
The Journal of Immunology 10/2003; 171(5):2625-30. · 5.79 Impact Factor
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ABSTRACT: Hyperoxia induces growth arrest, apoptosis, necrosis, and morphological changes (spreading and adhesion) in various types of cells. The mechanism of hyperoxia-induced cell growth arrest has not been well elucidated, especially in macrophages. One possible mechanism is a role of cell adhesion in hyperoxia-induced cell cycle arrest. To evaluate this finding, macrophages were cultured in normoxia (21% O2) or hyperoxia (95% O2) in adhesion or low adhesion conditions. Incubation of macrophages in hyperoxia induced cell cycle arrest. The hyperoxia-induced cell cycle arrest was prevented by low adhesion conditions. To evaluate pathways potentially involved in hyperoxia-induced growth arrest, we measured extracellular regulated kinase and retinoblastoma protein activation and p21Cip1 and p53 accumulation. Hyperoxia strongly induced activation of extracellular regulated kinase and retinoblastoma protein as well as up-regulation of p21Cip1. These effects of hyperoxia were attenuated under low adhesion conditions, suggesting a role for integrin-dependent signaling. The induction of p21Cip1 and activation of retinoblastoma protein occurred via a p53-independent mechanism. These results suggest that adhesion-dependent pathways are required for hyperoxia-induced cell cycle arrest in macrophages.
Journal of Biological Chemistry 10/2003; 278(38):36099-106. · 4.77 Impact Factor
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ABSTRACT: Current hypotheses of the pathogenesis of many forms of pulmonary fibrosis suggest that (i) a stimulus results in repeated or prolonged episodes of lung injury, and (ii) genetic factors modulate the outcome of the injury. The commonly employed single-exposure bleomycin model results in only temporary fibrosis. Therefore, we evaluated whether repeated bleomycin exposures, in the setting of a genetic background more likely to develop a T helper 2 (Th2) response, would induce prolonged fibrosis. Lung fibrosis was induced by intratracheal bleomycin injection, either as a single exposure or as three consecutive exposures. We found that bleomycin induced a Th2-like environment in both Th1-biased C57BL/6J and Th2-biased DBA/2 mice. We also found histologic changes and collagen increases consistent with lung injury/fibrosis at early time points, but prolonged fibrosis only after multiple exposures in the Th2-biased DBA/2 mice. We also determined if impaired healing of bleomycin-induced injury would prolong fibrosis in the C57BL/6J mice. Endothelial nitric oxide (which protects endothelial cells from oxidant-induced injury) synthase knockout animals on a C57BL/6J background also had prolonged fibrosis, similar to DBA/2 mice, after multiple bleomycin exposures. This was specific to eNOS, as inducible nitric oxide synthase knockout animals cleared the fibrosis as effectively as wild-type C57BL/6J mice. This data indicate that healing of injury/fibrosis after bleomycin is complex and can be determined by a number of genetic and environmental factors.
American Journal of Respiratory Cell and Molecular Biology 10/2003; 29(3 Pt 1):375-80. · 5.13 Impact Factor
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JAMA The Journal of the American Medical Association 07/2003; 289(24):3300-3. · 30.03 Impact Factor
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ABSTRACT: Stimulation via the T-cell receptor results in proliferation of naive T cells and activation-induced death of activated T cells. The expression of Fas ligand and activation-induced cell death are major mechanisms by which immune responses are modulated in the lung. Although it is known that the binding of integrin receptors to extracellular matrix proteins provides co-stimulatory signals to naive T cells, it is not clear whether these signals are critical for activated T cells. The activation and differentiation of T cells is marked by significant changes in integrin expression and affinity. To determine the role of integrin signaling in restimulation of activated T cells, we blocked integrin receptors with RGD peptides. Using murine activated CD4+ T cells and the T-cell hybridoma DO11.10, we found that RGD peptides inhibit tyrosine phosphorylation of CD3 epsilon-chain and ZAP-70, clustering of T-cell receptors, extracellular signal-regulated kinase mitogen-activated protein-kinase activation, and Fas ligand expression and prevent activation-induced cell death. We demonstrate that activated T cells are sensitive to integrin co-stimulation and that integrin receptors are required for the successful restimulation of activated T cells. This indicates that matrix proteins may play a major role in regulating T-cell-mediated immune responses in the lung.
American Journal of Respiratory Cell and Molecular Biology 06/2003; 28(5):607-15. · 5.13 Impact Factor
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ABSTRACT: Lung involvement in Crohn's disease is not well characterized. We reviewed our experience with 11 lung biopsies (seven wedge and four transbronchial) from patients with Crohn's disease to study this association further. Negative cultures, special stains for organisms Gomori-methenamine-silver [GMS], acid fast), and polymerase chain reaction for (four cases) were required for inclusion. The group included five women and six men with a mean age of 47 years (range 13-84 years). A diagnosis of Crohn's disease preceded the lung disease in nine patients. In two patients the diagnosis of Crohn's disease followed the diagnosis of their pulmonary disease 1 and 15 months later. Radiologically, eight patients had diffuse infiltrates, two had bilateral nodular infiltrates, and one had a mass. Chronic bronchiolitis with nonnecrotizing granulomatous inflammation was present in four patients, one of whom was taking mesalamine. Two patients had an acute bronchiolitis associated with a neutrophil-rich bronchopneumonia with suppuration and vague granulomatous features. One patient on mesalamine had cellular interstitial pneumonia with rare giant cells. Four patients demonstrated organizing pneumonia with focal granulomatous features, two of whom were taking mesalamine, and one of these two responded to infliximab (anti-tumor necrosis factor) monoclonal antibody therapy. Noninfectious pulmonary disease in patients with Crohn's disease has variable histologic appearances, including granulomatous inflammation and airway-centered disease resembling that seen in patients with ulcerative colitis. Drugs may contribute to pulmonary disease in some patients.
American Journal of Surgical Pathology 03/2003; 27(2):213-9. · 4.35 Impact Factor
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ABSTRACT: The alveolar macrophage responds to bacterial infection with the production of inflammatory mediators that include TNFalpha. Early production of TNFalpha results in increased bacterial clearance, whereas too much TNFalpha results in many of the hallmarks of bacterial sepsis. TNFalpha production is regulated at many levels, including multiple signaling pathways, that lead to transcription, translation, and release of functional TNFalpha. Interactions of mitogen-activated protein (MAP) kinases, lipid signaling pathways, and oxidant-mediated mechanisms regulate the response of alveolar macrophages to infection. Animal models of sepsis support the central role played by macrophage-derived TNFalpha in sepsis.
Annual Review of Physiology 02/2003; 65:643-67. · 20.83 Impact Factor
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ABSTRACT: Adverse immunological reactions to adenoviral vectors have significantly impacted the utility of this virus for treating genetic and environmentally induced diseases. In this study, we evaluate the effect of adenoviral vectors on an animal model of sepsis. Systemic delivery of first-generation adenoviral vectors to septic mice (cecal ligation and puncture) resulted in a shortened survival time. This effect was not observed with second-generation or inactivated first-generation vectors. The accelerated death was accompanied by a number of important changes in the disease. These changes included increased liver cell apoptosis (including Kupffer cells) and a marked increase in liver bacterial load. In the lung, the combination induced an increase in bacterial load, as well as greater lung injury. In the serum, the combination was associated with decreased TNF-alpha levels and an increase in bacterial load. Finally, a profound degree of lymphocyte apoptosis was observed in these animals. These observations suggest that prior exposure to first-generation adenovirus gene therapy vectors may worsen the outcome of some forms of sepsis.
The Journal of Immunology 01/2003; 169(11):6539-45. · 5.79 Impact Factor
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ABSTRACT: Previously, we have shown in a model of hypersensitivity pneumonitis that Th1-biased C57BL/6 mice are susceptible and Th2-biased DBA/2 mice are resistant to disease. We also showed that this was explained in part by differential regulation of IL-12 by IL-4. For these reasons, we postulated that C57BL/6 and DBA/2 mice differentially express IL-4. In this study, we show that C57BL/6 immune cells express Th2 but not Th1 cytokines at lower levels than DBA/2 cells. We also found that C57BL/6 splenocytes exhibit decreased mRNA stability of Th2 cytokines, relative to DBA/2 splenocytes. Stability of IL-2 and IFN-gamma were similar in the two strains of mice. Differences in Th2 cytokine mRNA stability between C57BL/6 and DBA/2 cells were not due to sequence polymorphism at specific regions of the IL-4/IL-13 locus. Furthermore, expression of Th1- and Th2-specific transcription factors T-bet and GATA-3, as well as the nuclear factor of activated T cells transcription factor, NFATc, was not significantly different between the two mice. Our data suggest that decreased mRNA stability of Th2 cytokines in C57BL/6 splenocytes may underlie the differential susceptibility to hypersensitivity pneumonitis between C57BL/6 and DBA/2 mice. Moreover, our results indicate that regulation of mRNA stability may serve as an important mechanism underlying Th1/Th2 immune polarization.
The Journal of Immunology 11/2002; 169(7):3700-9. · 5.79 Impact Factor
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ABSTRACT: Human alveolar macrophages have both lipopolysaccharide (LPS)-induced and constitutive phosphatidylinositol 3-kinase (PI3K) activity. We observed that blocking PI3K activity increased release of prostaglandin E2 after LPS exposure, and increasing PI3K activity (interleukin-13) decreased release of prostaglandin E2 after LPS exposure. This was not because of an effect of PI3K on phospholipase 2 activity. PI3K inhibition resulted in an increase in cyclooxygenase 2 (COX2) protein, mRNA, and mRNA stability. PI3K negatively regulated activation of the p38 pathway (p38, MKK3/6, and MAPKAP2), and an active p38 was necessary for COX2 production. The data suggest that PI3K inhibition of p38 modulates COX2 expression via destabilization of LPS-induced COX2 mRNA.
Journal of Biological Chemistry 10/2002; 277(36):32992-3000. · 4.77 Impact Factor
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ABSTRACT: Exposure of macrophages to endotoxin [lipopolysaccharide (LPS)] results in a cascade of events resulting in the release of multiple inflammatory and anti-inflammatory mediators. The Toll-like receptor (TLR) 4 complex is the major receptor that mediates LPS signaling. However, there is evidence that other surface molecules may play a complementary role in the TLR-induced events. Integrin receptors are one class of receptors that have been linked to LPS signaling. This study investigates the role of macrophage integrin receptors in the activation of mitogen-activated protein (MAP) kinases by LPS. In conditions where macrophages were not permitted to adhere to matrix or a tissue culture surface, we found a decrease in LPS signaling as documented by a marked reduction in tyrosine phosphorylation of whole cell proteins. This was accompanied by a significant decrease in extracellular signal-regulated kinase and c-Jun NH(2)-terminal kinase MAP kinase activation. Inhibition of integrin signaling, with EDTA or RGD peptides, decreased LPS-induced MAP kinase activity. The functional consequence of blocking integrin signaling was demonstrated by decreased LPS-induced tumor necrosis factor-alpha production. These observations demonstrate that, in addition to the TLR receptor complex, optimal LPS signaling requires complementary signals from integrin receptors.
AJP Lung Cellular and Molecular Physiology 09/2002; 283(2):L390-402. · 3.66 Impact Factor
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ABSTRACT: Extracellular signal-regulated kinases (ERKs) are key regulatory proteins that mediate cell survival, proliferation, and differentiation. Reactive oxygen species (ROS) may play a role in activation of the ERK pathway. Because mitochondria are a major source of ROS, we investigated whether mitochondria-derived ROS play a role in ERK activation. Diazoxide, a potent mitochondrial ATP-sensitive K+ (K(ATP)) channel opener, is known to depolarize the mitochondrial membrane potential and cause a reversible oxidation of respiratory chain flavoproteins, thus increasing mitochondrial ROS production. Using THP-1 cells as a model, we postulated that opening mitochondrial K(ATP) channels would increase production of ROS and, thereby, regulate the activity of the ERK kinase. We found that opening mitochondrial K(ATP) channels by diazoxide induced production of ROS as determined by an increased rate of dihydroethidium and dichlorofluorescein fluorescence. This increased production of ROS was associated with increased phosphorylation of ERK kinase in a time-dependent fashion. The MEK inhibitors PD-98059 and U-0126 blocked ERK activation mediated by diazoxide. N-acetylcysteine, but not diphenyleneiodonium, attenuated ERK activation mediated by diazoxide. Adenovirus-mediated overexpression of manganese superoxide dismutase, which is expressed in mitochondria, decreased the rate of dihydroethidium oxidation as well as ERK activation. We conclude that mitochondrial K(ATP) channel openers trigger ERK activation via mitochondria-derived ROS.
AJP Cell Physiology 08/2002; 283(1):C273-81. · 3.54 Impact Factor
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ABSTRACT: Alveolar macrophages have been implicated in the pathogenesis of a number of acute and chronic lung disorders. We have previously shown that normal human alveolar macrophages exhibit decreased DNA binding activity of the transcription factor, AP-1, compared with monocytes. Furthermore, this decrease in AP-1 DNA binding appears to be due to a decrease in the redox active protein, redox factor (Ref)-1. Ref-1 is an important redox regulator of a number of transcription factors, including NF-kappaB and AP-1. In this study we evaluated the role of asbestos, a prototypic model of chronic fibrotic lung disease, in Ref-1 expression and activity. We found that incubation with low concentrations of crocidolite asbestos (0.5-1.25 microg/cm(2)) resulted in an increase in nuclear Ref-1 protein after 5 min, with a persistent elevation in protein up to 24 h. Additionally, an increase in nuclear Ref-1 could be induced by treating the cells with an oxidant-generating stimulus (iron loading plus PMA) and inhibited by diphenyleneiodonium chloride, an inhibitor of NADPH oxidase. The asbestos-induced accumulation of nuclear Ref-1 was associated with an increase in AP-1 DNA binding activity. These findings suggest that an exposure associated with fibrotic lung disease, i.e., asbestos, modulates accumulation of nuclear Ref-1 in macrophages, and that this effect is mediated by an oxidant stimulus.
The Journal of Immunology 07/2002; 168(11):5675-81. · 5.79 Impact Factor
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ABSTRACT: Respiratory syncytial virus (RSV) infects airway epithelial cells, resulting in cell death and severe inflammation through the induction of NF-kappaB activity and inflammatory cytokine synthesis. Both NF-kappaB activity and apoptosis regulation have been linked to phosphatidylinositol 3-kinase (PI 3-K) and its downstream effector enzymes, AKT and GSK-3. This study evaluates the role of PI 3-K and its downstream mediators in apoptosis and inflammatory gene induction during RSV infection of airway epithelial cells. Whereas RSV infection alone did not produce significant cytotoxicity until 24-48 h following infection, simultaneous RSV infection and exposure to LY294002, a blocker of PI 3-K activity, resulted in cytotoxicity within 12 h. Furthermore, we found that RSV infection during PI 3-K blockade resulted in apoptosis by examining DNA fragmentation, DNA labeling by terminal dUTP nick-end labeling assay, and poly(ADP-ribose) polymerase cleavage by Western blotting. RSV infection produced an increase in the phosphorylation state of AKT, GSK-3, and the p85 regulatory subunit of PI 3-K. The activation of PI 3-K by RSV and its inhibition by LY294002 was confirmed in direct PI 3-K activity assays. Further evidence for the central role of a pathway involving PI 3-K and AKT in preserving cell viability during RSV infection was established by the observation that constitutively active AKT transfected into A549 cells prevented the cytotoxicity and apoptosis of combined RSV and LY294002 treatment. Finally, both PI 3-K inhibition by LY294002 and AKT inhibition by transfection of a dominant negative enzyme blocked RSV-induced NF-kappaB transcriptional activity. These data demonstrate that anti-apoptotic signaling and NF-kappaB activation by RSV are mediated through activation of PI 3-K-dependent pathways. Blockade of PI 3-K activation resulted in rapid, premature apoptosis and inhibition of RSV-stimulated NF-kappaB-dependent gene transcription.
Journal of Biological Chemistry 02/2002; 277(1):492-501. · 4.77 Impact Factor
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ABSTRACT: Reactive oxygen species (ROS) are important second messengers generated in response to many types of environmental stress.
In this setting, changes in intracellular ROS can activate signal transduction pathways that influence how cells react to
their environment. In sepsis, a dynamic proinflammatory cellular response to bacterial toxins (e.g. lipopolysaccharide or LPS) leads to widespread organ damage and death. The present study demonstrates for the first time
that the activation of Rac1 (a GTP-binding protein), and the subsequent production of ROS, constitutes a major pathway involved
in NFκB-mediated tumor necrosis factor-α (TNFα) secretion following LPS challenge in macrophages. Expression of a dominant
negative mutant of Rac1 (N17Rac1) reduced Rac1 activation, ROS formation, NFκB activation, and TNFα secretion following LPS
stimulation. In contrast, expression of a dominant active form of Rac1 (V12Rac1) mimicked these effects in the absence of
LPS stimulation. IKKα and IKKβ were both required downstream modulators of LPS-activated Rac1, since the expression of either
of the IKK dominant mutants (IKKαKM or IKKβKA) drastically reduced NFκB-dependent TNFα secretion. Moreover, studies using
CD14 blocking antibodies suggest that Rac1 induces TNFα secretion through a pathway independent of CD14. However, a maximum
therapeutic inhibition of LPS-induced TNFα secretion occurred when both CD14 and Rac1 pathways were inhibited. Our results
suggest that targeting both Rac1- and CD14-dependent pathways could be a useful therapeutic strategy for attenuating the proinflammatory
cytokine response during the course of sepsis.
Journal of Biological Chemistry 08/2001; 276(32):30188-30198. · 4.77 Impact Factor
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ABSTRACT: Endotoxin-induced cytokine gene transcription in monocytes and macrophages is regulated in part by NF-κB. We have previously
shown that the p38 mitogen-activated protein (MAP) kinase is necessary for endotoxin-induced cytokine gene transcription.
Due to the fact that most cytokine promoter sequences have active NF-κB sites, we hypothesized that the p38 MAP kinase was
necessary for NF-κB-dependent gene expression. We found that NF-κB-dependent gene expression was reduced to near control levels
with either SB 203580 or a dominant-negative p38 MAP kinase expression vector. Inhibition of the p38 MAP kinase did not alter
NF-κB activation at any level, but it significantly reduced the DNA binding of TATA-binding protein (TBP) to the TATA box.
The dominant-negative p38 MAP kinase expression vector interfered with the direct interaction of native TFIID (TBP) with a
co-transfected p65 fusion protein. Likewise, this dominant-negative plasmid also interfered with the direct interaction of
a co-transfected TBP fusion protein with the native p65 subunit. The p38 kinase also phosphorylated TFIID (TBP) in vitro, and SB 203580 inhibited phosphorylation of TFIID (TBP) in vivo. Thus, the p38 MAP kinase regulates NF-κB-dependent gene transcription, in part, by modulating activation of TFIID (TBP).
Journal of Biological Chemistry 10/1999; 274(43):30858-30863. · 4.77 Impact Factor
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ABSTRACT: The fetal respiratory distress syndrome is due, in part, to the presence of abundant pre-type II alveolar epithelial cells
that have not yet differentiated into mature type II cells. Studies of this syndrome have been limited somewhat by the lack
of an adequate in vitro model. In the present study we immortalized pre-type II cells by infecting primary isolates obtained
from fetal rat lung with a retroviral construct expressing the adenoviral 12S E1A gene product. The immortalized pre-type
II cells retained many of the ultrastructural features typical of pre-type II cells in primary culture, most notably lamellar
bodies were not detected and the cells contained abundant stores of glycogen, expressed cytokeratin filaments, and bound the
lectinMaclura pomifera. Karyotyping revealed that the cells are diploid. Growth studies demonstrate log phase growth in the presence of serum with
a markedly decreased growth rate shortly after the cells reach confluence. Exposure of the immortalized pre-type II cells
to hydrocortisone and dibutryl cAMP resulted in the induction of lamellar bodylike organelles; however, these cells did not
secrete surfactant or express surfactant protein A. These cells may serve as useful models for some in vitro studies of fetal
type II cell maturation or the fetal respiratory distress syndrome, or both.
In Vitro Cellular & Developmental Biology - Animal 04/1992; 28(3):181-187. · 1.31 Impact Factor
