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T Collins

Publications and source records attributed to T Collins.

At least 109 records · Page 6Linked to original sources
PubMed1995

Nuclear factor-kappa B mediates induction of vascular cell adhesion molecule-1 in glomerular mesangial cells.

Cultured glomerular mesangial cells (GMCs) can be activated at the transcriptional level by a variety of physiologically relevant factors including cytokines, endotoxin and glycosylated end products. The mechanism with which the signal is transduced from the membrane to the nucleus of these cells is largely unclear. In vascular endothelial cells, the signal transduction pathway involves activation of the pleuripotent transcription factor, NF-kappa B, and leads to increased expression of a variety of genes including vascular cell adhesion molecule-1 (VCAM-1). Here, we demonstrate that TNF-alpha and IL-1 beta transiently induced VCAM-1 mRNA expression in a time dependent manner. TNF-alpha also induced the specific interaction of proteins from GMC nuclei with an oligonucleotide bearing the NF-kappa B binding sites in the VCAM-1 promoter. Electrophoretic mobility shift and supershift analysis indicated that the p65 subunit of NF-kappa B is a component of this induced complex. Finally, reporter activity driven by a VCAM-1 promoter-chloramphenicol acetyltransferase reporter construct increased 8-10 fold following TNF-alpha incubation, or p65 cotransfection. Thus, the p65 subunit of NF-kappa B is activated in GMCs exposed to cytokine and can mediate induction of gene expression.

Animals↗
PubMed1995

The proteasome pathway is required for cytokine-induced endothelial-leukocyte adhesion molecule expression.

Multiple cell adhesion proteins are up-regulated in vascular endothelial cells in response to TNF alpha and other inflammatory cytokines. This increase in cell adhesion gene expression is thought to require the transcription factor NF-kappa B. Here, we show that peptide aldehyde inhibitors of the proteasome, a multicatalytic protease recently shown to be required for the activation of NF-kappa B, block TNF alpha induction of the leukocyte adhesion molecules E-selectin, VCAM-1, and ICAM-1. Striking functional consequences of this inhibition were observed in analyses of leukocyte-endothelial interactions under defined flow conditions. Lymphocyte attachment to TNF alpha-treated endothelial monolayers was totally blocked, while neutrophil attachment was partially reduced but transmigration was essentially prevented.

Base Sequence↗
PubMed1995

Severe acidosis alone does not predict mortality in the trauma patient.

BACKGROUND: Because severe acidosis is an indicator of poor prognosis in trauma patients, medical records of these patients were analyzed to determine whether aggressive resuscitation was appropriate. PATIENTS AND METHODS: Data from a level 1 trauma center registry were reviewed retrospectively to identify patients with a pH < or = 7.0. Thirty-seven patients were identified. Severely acidotic patients were compared to average trauma patients in terms of demographics, resuscitation, injury, and outcome. Surviving acidotic patients were also compared to nonsurviving acidotic patients. RESULTS: Half of the severely acidotic group survived initial resuscitation with approximately one third surviving to leave the hospital. There were no chronically disabled survivors. Nonsurviving acidotic patients were more unstable, more neurologically depressed, and more severely injured. Resuscitation efforts did not consume excessive hospital resources. CONCLUSION: Severe acidosis alone is not a sufficiently powerful predictor of outcome to justify withholding resuscitation; however, when combined with coma and shock, this condition had no survivors in this small series.

Acidosis↗
PubMed1995

Respiratory chlamydia: the management of an outbreak.

This investigation was undertaken in response to the occurrence of nine cases of respiratory chlamydial infection in 8 months within the district of Dudley. All nine cases of respiratory chlamydia were due to Chlamydia psittaci, not Chlamydia pneumoniae. Five cases had avian exposure, but no other aetiological factors were identified. Faecal specimens were obtained from only two of the implicated birds and were negative. Two local aviaries were identified as sources of implicated birds. The two aviaries were themselves linked. Bird faecal specimens were taken from the two implicated aviaries and were both positive for Chlamydia psittaci. Appropriate public health control measures were introduced in these aviaries. A press statement was released to identify and advise, by telephone, those who purchased birds from the aviaries.

Adult↗
PubMed1995

Endothelial interferon regulatory factor 1 cooperates with NF-kappa B as a transcriptional activator of vascular cell adhesion molecule 1.

Transcription of the vascular cell adhesion molecule 1 (VCAM-1) gene in endothelial cells is induced by lipopolysaccharide and the inflammatory cytokines interleukin-1 beta and tumor necrosis factor alpha (TNF-alpha). Previous studies have demonstrated that tandem binding sites for the inducible transcription factor NF-kappa B are necessary but not sufficient for full cytokine-mediated transcriptional activation. Herein, we demonstrate that full cytokine-induced accumulation of VCAM1 transcript requires protein synthesis. We report the definition of a functional regulatory element in the VCAM1 promoter interacting with the transcriptional activator interferon regulatory factor 1 (IRF-1). DNA-protein binding studies with endothelial nuclear extracts revealed that IRF-1 is cytokine inducible and binds specifically to a consensus sequence motif located 3' of the TATA element. We have identified heterodimeric p65 and p50 as the NF-kappa B species binding to the VCAM1 promoter in TNF-alpha-activated endothelial cells. Experiments with recombinant proteins showed that p50/p65 and high-mobility-group I(Y) protein cooperatively facilitated the binding of IRF-1 to the VCAM1 IRF binding site and that IRF-1 physically interacted with p50 and with high-mobility-group I(Y) protein. Transient transfection assay in endothelial cells showed that overexpressed IRF-1 resulted in superinduction of TNF-alpha-stimulated transcription. Site-directed mutations in the IRF binding element decreased TNF-alpha-induced activity and totally abolished superinduction. Cotransfection assays in P19 embryonal carcinoma cells revealed that IRF-1 synergized with p50/p65 NF-kappa B to activate the VCAM1 promoter or heterologous promoter constructs bearing isolated VCAM1 NF-kappa B and IRF binding motifs. Cytokine inducibility of VCAM1 in endothelial cells utilizes the interaction of heterodimeric p50/p65 proteins with IRF-1.

Base Sequence↗
PubMed1995

Absence/hypoplasia of tibia, polydactyly, retrocerebellar arachnoid cyst, and other anomalies: an autosomal recessive disorder.

Absence or hypoplasia of the tibia has been reported to occur as an isolated hereditary malformation as well as a feature of several autosomal recessive and autosomal dominant syndromes. We report three sibs with absence or hypoplasia of the tibia in association with other malformations whose parents are first cousins once removed. These infants appear to have a "new" autosomal recessive syndrome.

Abnormalities, Multiple↗
PubMed1995

Nuclear factor-kappa B interacts functionally with the platelet-derived growth factor B-chain shear-stress response element in vascular endothelial cells exposed to fluid shear stress.

Hemodynamic forces, such as fluid shear stress, that act on the endothelial lining of the cardiovascular system can modulate the expression of an expanding number of genes crucial for homeostasis and the pathogenesis of vascular disease. A 6-bp core element (5'-GAGACC-3'), defined previously as a shear-stress response element is present in the promoters of many genes, including the PDGF B-chain, whose expression is modulated by shear stress. The identity of the nuclear protein(s) binding to this element has not yet been elucidated. Using electrophoretic mobility shift assays and in vitro DNase I footprinting, we demonstrate that nuclear factor-kappa B p50-p65 heterodimers, which accumulate in the nuclei of cultured vascular endothelial cells exposed to fluid shear stress, bind to the PDGF-B shear-stress response element in a specific manner. Mutation of this binding motif abrogated its interaction with p50-p65 and abolished the ability of the promoter to mediate increased gene expression in endothelial cells exposed to shear stress. Transient cotransfection studies indicate that p50-p65 is able to activate PDGF-B shear-stress response element-dependent reporter gene expression in these cells. These findings thus implicate nuclear factor-kappa B in the transactivation of an endothelial gene responding to a defined fluid mechanical force.

Animals↗
PubMed1995

Development and testing of nursing home quality indicators.

In this article, the authors report on the development and testing of a set of indicators of quality of care in nursing homes, using resident-level assessment data. These quality indicators (QIs) have been developed to provide a foundation for both external and internal quality-assurance (QA) and quality-improvement activities. The authors describe the development of the QIs, discuss their nature and characteristics, address the development of a QI-based quality-monitoring system (QMS), report on a pilot test of the QIs and the system, comment on methodological and current QI validation efforts, and conclude by raising further research and development issues.

Accidental Falls↗
PubMed1995

Transcriptional regulation of endothelial cell adhesion molecules: NF-kappa B and cytokine-inducible enhancers.

Transcription of endothelial-leukocyte adhesion molecule-1 (E-selectin or ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) is induced by the inflammatory cytokines interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF alpha). The positive regulatory domains required for maximal levels of cytokine induction have been defined in the promoters of all three genes. DNA binding studies reveal a requirement for nuclear factor-kappa B (NF-kappa B) and a small group of other transcriptional activators. The organization of the cytokine-inducible element in the E-selectin promoter is remarkably similar to that of the virus-inducible promoter of the human interferon-beta gene in that both promoters require NF-kappa B, activating transcription factor-2 (ATF-2), and high mobility group protein I(Y) for induction. Based on this structural similarity, a model has been proposed for the cytokine-induced E-selectin enhancer that is similar to the stereospecific complex proposed for the interferon-beta gene promoter. In these models, multiple DNA bending proteins facilitate the assembly of higher order complexes of transcriptional activators that interact as a unit with the basal transcriptional machinery. The assembly of unique enhancer complexes from similar sets of transcriptional factors may provide the specificity required to regulate complex patterns of gene expression and correlate with the distinct patterns of expression of the leukocyte adhesion molecules.

Base Sequence↗
PubMed1994

Novel cis-acting elements in the human platelet-derived growth factor B-chain core promoter that mediate gene expression in cultured vascular endothelial cells.

Platelet-derived growth factor (PDGF) is a potent mitogen and chemoattractant constitutively expressed by a variety of normal and transformed cells. Transient transfection and deletion analysis of the human c-sis proto-oncogene in cultured vascular endothelial cells revealed a minimal core promoter region extending 82 base pairs upstream from the TATA box. Two novel and functional cis-acting elements were identified within the core that share considerable sequence homology with consensus binding elements for transacting factors of the ETS class and those involved in AP-1 complexes. Deletion or mutation of either the ETS-like site or the AP-1-like site resulted in significant attenuation in the ability of the core to drive transcription. Electrophoretic mobility shift assays revealed that proteins from bovine aortic and human umbilical vein endothelial nuclear extracts bound to these elements in a specific manner and that both sites were essential for protein binding. Ferguson analysis predicted a combined molecular mass of 153 kDa for these proteins. In addition, transient transfection, gel shift, and DNase I footprint analysis were used to identify a functional Sp1 binding site downstream of these elements in the core promoter. By localizing the functional cis-acting elements in the PDGF-B promoter, it may be possible to elucidate the normal transcriptional control of the gene, as well as the mechanisms that activate it in pathologic settings.

Animals↗
PubMed1994

cAMP and tumor necrosis factor competitively regulate transcriptional activation through and nuclear factor binding to the cAMP-responsive element/activating transcription factor element of the endothelial leukocyte adhesion molecule-1 (E-selectin) promoter.

The cAMP-responsive element/activating transcription factor (CRE/ATF) element (also known as NF-ELAM1) of the endothelial leukocyte adhesion molecule-1 (ELAM-1) promoter is necessary for full cytokine responsiveness. It differs from a consensus cAMP-responsive element (CRE) by 1 nucleotide (G-->A conversion) and does not mediate transcriptional activation in response to cAMP. We reported previously that cAMP actually decreases ELAM-1 synthesis induced by tumor necrosis factor (TNF). We now show that cAMP decreases the ELAM-1 promoter response to TNF in transient transfection assays in bovine aortic endothelial cells and that cAMP-mediated inhibition maps to the CRE/ATF element. Electrophoretic mobility shift assays using the ELAM-1 CRE/ATF DNA sequence reveal three complexes. Antibody supershift assays suggest the slowest migrating form (complex 1) contains ATF2, the middle form (complex 2) contains ATF2 and c-Jun, and the fastest migrating form (complex 3) contains a CRE-binding protein. TNF increases c-Jun-containing complex 2 while diminishing complex 1, whereas cAMP decreases complex 2 and increases complex 1. Complex 3 is unchanged by either treatment, and the CRE-binding protein is not phosphorylated. Our data suggest that a change in the composition of the proteins binding to the CRE/ATF promoter element contributes to the competing effects of TNF and cAMP on ELAM-1 gene expression.

Animals↗
PubMed1994

NF-kappa B and I kappa B alpha: an inducible regulatory system in endothelial activation.

Structural analysis of the promoters of several endothelial genes induced at sites of inflammatory or immune responses reveals binding sites for the transcription factor nuclear factor kappa B (NF-kappa B). Endothelial cells express transcripts encoding the p50/p105 and p65 components of NF-kappa B and the rel-related proto-oncogene c-rel; steady state levels of these transcripts are transiently increased by tumor necrosis factor alpha (TNF-alpha). Western blotting revealed that stimulation of endothelial cells with TNF-alpha resulted in nuclear accumulation of the p50 and p65 components of NF-kappa B. Ultraviolet crosslinking and immunoprecipitation demonstrated binding of the p50 and p65 components of NF-kappa B to the E-selectin kappa B site. Endothelial cells express an inhibitor of NF-kappa B activation, I kappa B-alpha (MAD-3). Protein levels of this inhibitor fall rapidly after TNF-alpha stimulation. In parallel, p50 and p65 accumulate in the nucleus and RNA transcript levels for I kappa B-alpha are dramatically upregulated. Recombinant p65 stimulates expression of E-selectin promoter-reporter constructs. I kappa B-alpha inhibits p65 or TNF-alpha-stimulated E-selectin promoter-reporter gene expression in transfected endothelial cells. The NF-kappa B and I kappa B-alpha system may be an inducible regulatory mechanism in endothelial activation.

Animals↗
PubMed1994

Intratracheal administration of endotoxin and cytokines: VIII. LPS induces E-selectin expression; anti-E-selectin and soluble E-selectin inhibit acute inflammation.

E-selectin is an inducible endothelial adhesion molecule that binds neutrophils. E-selectin mRNA is not constitutively detectable in the lungs of rats. Intratracheal injection of LPS induces pulmonary E-selectin mRNA expression at 2-4 h. Intratracheal injection of LPS followed at 2 and 4 h by intravenous injection of mouse F(ab')2 or F(ab') anti-E-selectin monoclonal antibody inhibits the emigration of neutrophils into the bronchoalveolar space at 6 h by 50-70%. TNF and IL-6 bioactivity are not decreased in bronchoalveolar lavage fluid after treatment with anti-E-selectin antibody as compared to controls, suggesting that the anti-E-selectin does not affect the magnitude of the LPS-initiated cytokine cascade. Intratracheal injection of LPS followed at 2 and 4 h by intravenous injection of soluble E-selectin inhibits neutrophilic emigration at 6 h by 64%, suggesting that endogenous soluble E-selectin shed from activated endothelium may play a role in the endogenous down-regulation of acute inflammation. E-selectin-mediated adhesion of neutrophils to endothelium appears crucial to the full development of the acute inflammation response.

Acute Disease↗
PubMed1994

A striking similarity in the organization of the E-selectin and beta interferon gene promoters.

Transcription of the endothelial leukocyte adhesion molecule 1 (E-selectin or ELAM-1) gene is induced by the inflammatory cytokines interleukin-1 beta and tumor necrosis factor alpha (TNF-alpha). In this report, we identify four positive regulatory domains (PDI to PDIV) in the E-selectin promoter that are required for maximal levels of TNF-alpha induction in endothelial cells. In vitro DNA binding studies reveal that two of the domains contain novel adjacent binding sites for the transcription factor NF-kappa B (PDIII and PDIV), a third corresponds to a recently described CRE/ATF site (PDII), and a fourth is a consensus NF-kappa B site (PDI). Mutations that decrease the binding of NF-kappa B to any one of the NF-kappa B binding sites in vitro abolished cytokine-induced E-selectin gene expression in vivo. Previous studies demonstrated a similar correlation between ATF binding to PDII and E-selectin gene expression. Here we show that the high-mobility-group protein I(Y) [HMG I(Y)] also binds specifically to the E-selectin promoter and thereby enhances the binding of both ATF-2 and NF-kappa B to the E-selectin promoter in vitro. Moreover, mutations that interfere with HMG I(Y) binding decrease the level of cytokine-induced E-selectin expression. The organization of the TNF-alpha-inducible element of the E-selectin promoter is remarkably similar to that of the virus-inducible promoter of the human beta interferon gene in that both promoters require NF-kappa B, ATF-2, and HMG I(Y). We propose that HMG I(Y) functions as a key architectural component in the assembly of inducible transcription activation complexes on both promoters.

Activating Transcription Factor 2↗
PubMed1993

Platelet-derived growth factor B chain promoter contains a cis-acting fluid shear-stress-responsive element.

The endothelial lining of blood vessels is constantly exposed to fluid mechanical forces generated by flowing blood. In vitro application of fluid shear stresses to cultured endothelial cells influences the expression of multiple genes, as reflected by changes in their steady-state mRNA levels. We have utilized the B chain of platelet-derived growth factor (PDGF-B) as a model to investigate the mechanisms of shear-stress-induced gene regulation in cultured bovine aortic endothelial cells (BAECs). Northern blot analysis revealed elevated endogenous PDGF-B transcript levels in BAECs, after exposure to a physiological level of laminar shear stress (10 dynes/cm2; 1 dyne = 100 mN) for 4 h. A transfected reporter gene, consisting of a 1.3-kb fragment of the human PDGF-B promoter coupled to chloramphenicol acetyltransferase (CAT), indicated a direct effect on transcriptional activity. Transfection of a series of PDGF-B-CAT deletion mutants led to the characterization of a cis-acting component within the PDGF-B promoter that was necessary for shear-stress responsiveness. In gel-shift assays, overlapping oligonucleotide probes of this region formed several protein-DNA complexes with nuclear extracts prepared from both static and shear-stressed BAECs. A 12-bp component (CTCTCAGAGACC) was identified that formed a distinct pattern of complexes with nuclear proteins extracted from shear-stressed BAECs. This shear-stress-responsive element does not encode binding sites for any known transcription factor but does contain a core binding sequence (GAGACC), as defined by deletion mutation in gel-shift assays. Interestingly, this putative transcription factor binding site is also present in the promoters of certain other endothelial genes, including tissue plasminogen activator, intercellular adhesion molecule 1, and transforming growth factor beta 1, that also are induced by shear stress. Thus, the expression of PDGF-B and other pathophysiologically relevant genes in vascular endothelium appears to be regulated, in part, by shear-stress-induced transcription factors interacting with a common promoter element.

Animals↗