Allan Brasier - Academia.edu (original) (raw)

Papers by Allan Brasier

Clinical and Translational Science, 2015

Multiinstitutional research collaborations now form the most rapid and productive project executi... more Multiinstitutional research collaborations now form the most rapid and productive project execution structures in the health sciences. Effective adoption of a multidisciplinary team research approach is widely accepted as one mechanism enabling rapid translation of new discoveries into interventions in human health. Although the impact of successful team-based approaches facilitating innovation has been well-documented, its utility for training a new generation of scientists has not been thoroughly investigated. We describe the characteristics of how multidisciplinary translational teams (MTTs) promote career development of translational research scholars through competency building, interprofessional integration, and team-based mentoring approaches. Exploratory longitudinal and outcome assessments from our experience show that MTT membership had a positive effect on the development of translational research competencies, as determined by a self-report survey of 32 scholars. We also observed that all trainees produced a large number of collaborative publications that appeared to be associated with their CTSA association and participation with MTTs. We conclude that the MTT model provides a unique training environment for translational and team-based learning activities, for investigators at early stages of career development. Clin Trans Sci 2015; Volume #: 1-9

International review of qualitative research : IRQR, 2013

We apply a symbolic interactionist framework and a qualitative methodology to the examination of ... more We apply a symbolic interactionist framework and a qualitative methodology to the examination of the everyday reality of translational science research (TSR). This is a growing scientific movement that aims to facilitate the efficient application of basic research to clinical service design and delivery. We describe the emerging culture of translational research at a mid-size medical center that received a Clinical and Translational Science Award from the National Institutes of Health. The stories related by scientists, clinicians, and students in interviews indicate that they make sense of the emerging inter- and cross-disciplinary, team-oriented culture of TSR through the refinement and redefinition of the significant symbols that inform their work while they attempt to master translational research by addressing the dilemmas it produces for them and their work. We see the strength, currency, adaptability, and energy of the core self-definition of "scientist" to be signi...

Proteomics, Jan 13, 2015

Despite years of preclinical development, biological interventions designed to treat complex dise... more Despite years of preclinical development, biological interventions designed to treat complex diseases like asthma often fail in phase III clinical trials. These failures suggest that current methods to analyze biomedical data might be missing critical aspects of biological complexity such as the assumption that cases and controls come from homogeneous distributions. Here we discuss why and how methods from the rapidly evolving field of visual analytics can help translational teams (consisting of biologists, clinicians, and bioinformaticians) to address the challenge of modeling and inferring heterogeneity in the proteomic and phenotypic profiles of patients with complex diseases. Because a primary goal of visual analytics is to amplify the cognitive capacities of humans for detecting patterns in complex data, we begin with an overview of the cognitive foundations for the field of visual analytics. Next, we organize the primary ways in which a specific form of visual analytics called...

Journal of immunology (Baltimore, Md. : 1950), 2014

8-Oxoguanine-DNA glycosylase-1 (OGG1) is the primary enzyme for repairing 7,8-dihydro-8-oxoguanin... more 8-Oxoguanine-DNA glycosylase-1 (OGG1) is the primary enzyme for repairing 7,8-dihydro-8-oxoguanine (8-oxoG) via the DNA base excision repair pathway (OGG1-BER). Accumulation of 8-oxoG in the genomic DNA leads to genetic instability and carcinogenesis and is thought to contribute to the worsening of various inflammatory and disease processes. However, the disease mechanism is unknown. In this study, we proposed that the mechanistic link between OGG1-BER and proinflammatory gene expression is OGG1's guanine nucleotide exchange factor activity, acquired after interaction with the 8-oxoG base and consequent activation of the small GTPase RAS. To test this hypothesis, we used BALB/c mice expressing or deficient in OGG1 in their airway epithelium and various molecular biological approaches, including active RAS pulldown, reporter and Comet assays, small interfering RNA-mediated depletion of gene expression, quantitative RT-PCR, and immunoblotting. We report that the OGG1-initiated rep...

Free radical biology & medicine, Jan 19, 2015

Reactive oxygen species inflict oxidative modifications on various biological molecules, includin... more Reactive oxygen species inflict oxidative modifications on various biological molecules, including DNA. One of the most abundant DNA base lesions 8-oxo-7,8-dihydroguanine (8-oxoG) is repaired by 8-oxoguanine DNA glycosylase-1 (OGG1) during DNA base excision repair (OGG1-BER). 8-OxoG accumulation in DNA has been associated with various pathological and aging processes, while its role is unclear. The lack of OGG1-BER in Ogg1-/- mice resulted in decreased inflammatory responses, increased susceptibility to infections and metabolic disorders. Therefore, we proposed that OGG1 and/or 8-oxoG base may have a role in immune and homeostatic processes. To test our hypothesis, we challenged mouse lungs with OGG1-BER product 8-oxoG base and changes in gene expression were determined by RNA sequencing and data were analyzed by gene ontology and statistical tools. RNA-Seq analysis identified 1592 differentially expressed (≥ 3-fold change) transcripts. The upregulated mRNAs were related to biologic...

PLoS ONE, 2012

Background: A series of epidemiologic studies have identified the fungus Alternaria as a major ri... more Background: A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epitheliumderived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation.

PLoS ONE, 2014

We present an integrated dynamical cross-talk model of the epithelial innate immune reponse (IIR)... more We present an integrated dynamical cross-talk model of the epithelial innate immune reponse (IIR) incorporating RIG-I and TLR3 as the two major pattern recognition receptors (PRR) converging on the RelA and IRF3 transcriptional effectors. bioPN simulations reproduce biologically relevant gene-and protein abundance measurements in response to time course, gene silencing and dose-response perturbations both at the population and single cell level. Our computational predictions suggest that RelA and IRF3 are under auto-and cross-regulation. We predict, and confirm experimentally, that RIG-I mRNA expression is controlled by IRF7. We also predict the existence of a TLR3-dependent, IRF3-independent transcription factor (or factors) that control(s) expression of MAVS, IRF3 and members of the IKK family. Our model confirms the observed dsRNA dose-dependence of oscillatory patterns in single cells, with periods of 1-3 hr. Model fitting to time series, matched by knockdown data suggests that the NF-kB module operates in a different regime (with different coefficient values) than in the TNFa-stimulation experiments. In future studies, this model will serve as a foundation for identification of virus-encoded IIR antagonists and examination of stochastic effects of viral replication. Our model generates simulated time series, which reproduce the noisy oscillatory patterns of activity (with 1-3 hour period) observed in individual cells. Our work supports the hypothesis that the IIR is a phenomenon that emerged by evolution despite highly variable responses at an individual cell level.

Oncogene, 2001

In chronic myelogenous leukemia (CML), the oncogene bcr-abl encodes a dysregulated tyrosine kinas... more In chronic myelogenous leukemia (CML), the oncogene bcr-abl encodes a dysregulated tyrosine kinase that inhibits apoptosis. We showed previously that human erythroleukemia K562 cells are resistant to antineoplastic drug (taxol)-induced apoptosis through the atypical protein kinase C iota isozyme (PKCι), a kinase downstream of Bcr-Abl. The mechanism(s) by which PKCι mediates cell survival to taxol is unknown. Here we demonstrate that PKCι requires the transcription factor nuclear factor-κB (NF-κB) to confer cell survival. At apoptosis-inducing concentrations, taxol weakly induces IκBα proteolysis and NF-κB translocation in K562 cells, but potently induces its transcriptional activity. Inhibition of NF-κB activity (by blocking IκBα degradation) significantly sensitizes cells to taxol-induced apoptosis. Likewise, K562 cells expressing antisense PKCι mRNA or kinase dead PKCι (PKCι-KD) are sensitized to taxol; these cells are rescued from apoptosis by NF-κB overexpression. Expression of constitutively active PKCι (PKCι-CA) upregulates NF-κB transactivation and rescues cells from apoptosis in the absence of Bcr-Abl tyrosine kinase activity. Using a chimeric GAL4-RelA transactivator, we find that taxol potently activates GAL4-RelA-dependent transcription. This activation was further upregulated by expression of PKCι-CA and inhibited by expression of PKCι-KD. Our results indicate that RelA transactivation is an important downstream target of the PKCι-mediated Bcr-Abl signaling pathway and is required for resistance to taxol-induced apoptosis.

Molecular Endocrinology, 2007

Kidney International, 1994

Transcripting factors modulating angiotensinogen gene expression in hepatocytes. The gene encodin... more Transcripting factors modulating angiotensinogen gene expression in hepatocytes. The gene encoding angiotensinogen is regulated at the transcriptional level in hepatocytes in response to glucocorticoids and inflammatory cytokines (IL-i and TNF). These hormones activate transcription of the angiotensinogen gene by changing the abundance of DNA binding proteins that interact with a multihormone-inducible enhancer located between nucleotides -615 to -440 upstream of the major transcription start site. Activation of this enhancer in hepatocytes is effected by glucocorticoid-and cytokine-inducible DNA binding proteins. Cytokine induction is mediated through the interaction of two classes of transcription factors that bind to the acute-phase response element (APRE): nuclear factor-KB (NF-B), and CCAAT-Box/Enhancer Binding Protein (C/EBP). NF-KB is a multiprotein DNA binding complex sequestered in the cytoplasm that is induced in the nucleus by cytokines, whereas C/EBP is a nuclear transcription factor family implicated in the expression of differentiated hepatic proteins. During the acute-phase response, individual C/EBP family members are discordinately regulated: C/EBPa levels fall, whereas another CIEBP family member termed nuclear factor 1L6 (NF-1L6), is induced. We investigated the interaction between the two acute-phase induced APRE-binding proteins: NF-KB and NF-1L6. Both proteins bind to overlapping nucleotides in a mutually exclusive fashion with similar affinities for the APRE. NF-1L6, a less potent transactivator, attenuates NF-KB mediated transcription late in the evolution of the acute-phase response. These observations argue for a temporal model of sequentially-expressed transcription factors occupying the APRE during the evolution of the inflammatory process.

Journal of Virology, 2005

Journal of Virology, 2003

RSV replication is a potent activator of the epithelial-cell genomic response, influencing the ex... more RSV replication is a potent activator of the epithelial-cell genomic response, influencing the expression of a spectrum of cellular pathways, including proinflammatory chemokines of the CC, CXC, and CX 3 C subclasses. Ribavirin (1-␤-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a nontoxic antiviral agent currently licensed for the treatment of severe RSV lower respiratory tract infections. Because ribavirin treatment reduces the cytopathic effect in infected cells, we used high-density microarrays to investigate the hypothesis that ribavirin modifies the virus-induced epithelial genomic response to replicating virus. Ribavirin treatment administered in concentrations of 10 to 100 g/ml potently inhibited RSV transcription, thereby reducing the level of RSV N transcripts to ϳ13% of levels in nontreated cells. We observed that in both the absence and the presence of ribavirin, RSV infection induced global alterations in the host epithelial cell, affecting ϳ49% of the ϳ6,650 expressed genes detectable by the microarray. , complement products, acute-phase response factors, and the STAT and IRF transcription factors. Because IFN-␤ expression itself was reduced in the ribavirin-treated cells, we further investigated the mechanism for up-regulation of the IFN-signaling pathway. Enhanced expression of IFI 6-16, IFI 9-27, MxA/p78, STAT-1␣, STAT-1␤, IRF-7B, and TAP-1-LMP2 transcripts were independently reproduced by Northern blot analysis. Ribavirin-enhanced TAP-1-LMP2 expression was a transcriptional event where site mutations of the IFN-stimulated response element (ISRE) blocked RSV and ribavirin-inducible promoter activity. Furthermore, ribavirin up-regulated the transcriptional activity of a reporter gene selectively driven by the ISRE. In specific DNA pull-down assays, we observed that ribavirin enhanced RSV-induced STAT-1 binding to the ISRE. We conclude that ribavirin potentiates virus-induced ISRE signaling to enhance the expression of antiviral ISGs, suggesting a mechanism for the efficacy of combined treatment with ribavirin and IFN in other chronic viral diseases.

Journal of Virology, 2005

signaling pathways by complexing with them and recruiting HDAC-1 to attenuate target promoter act... more signaling pathways by complexing with them and recruiting HDAC-1 to attenuate target promoter activity.

The Journal of Immunology, 2014

Journal of Allergy and Clinical Immunology, 2008

Background-Asthma is a heterogeneous clinical disorder. Methods for objective identification of d... more Background-Asthma is a heterogeneous clinical disorder. Methods for objective identification of disease subtypes will focus on clinical interventions and help identify causative pathways. Few studies have explored phenotypes at a molecular level.

Gastroenterology, 2004

Background & Aims: Gastric mucosal interleukin (IL)-8 levels are related to the presence of both ... more Background & Aims: Gastric mucosal interleukin (IL)-8 levels are related to the presence of both the cag pathogenicity island (PAI) and OipA. We investigated the regions of the IL-8 promoter and the upstream signaling involved in IL-8 gene transcription. Methods: We cocultured parental Helicobacter pylori and isogenic oipA, hopZ, or cagE gene knockout mutants with gastric cancer cells. The regulatory sites in the IL-8 promoter were examined by luciferase reporter gene assay, electrophoretic mobility shift assays, and immunoblot analyses. Phosphorylated signal transducers and activators of transcription 1 (STAT1) levels in the antral gastric mucosa were measured by enzyme-linked immunosorbent assay. Results: Maximal H. pylori-induced IL-8 gene transcription required the presence of the interferon-stimulated responsive element (ISRE)-like element, nuclear factor (NF)-B and activator protein (AP)-1 binding sites. In vitro studies showed that OipA and the cag PAI were involved in inducing interferon regulatory factor (IRF)-1 to bind and activate the ISRE-like element and that the cag PAI, but not OipA, was involved in activating AP-1 and NF-B. Both in vitro and in vivo studies showed that OipA, but not the cag PAI, was involved in STAT1 phosphorylation, as upstream signaling of IRF-1. Conclusions: OipA and the cag PAI are both necessary for full activation of the IL-8 promoter but act via different pathways that diverge upstream of IRF-1 where only OipA is involved in the STAT1-IRF1-ISRE pathway. The mucosal inflammatory response to H. pylori infection is complex and involves different pathways converging on the IL-8 promoter.

Free Radical Biology and Medicine, 2014

The user has requested enhancement of the downloaded file. All in-text references underlined in b... more The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

American Journal of Tropical Medicine and Hygiene, 2012

Cellular Signalling, 2015

a b s t r a c t 1 1 Available online xxxx 17 Keywords: 18 Mixed-effects modeling 19 EMT 20 Cellul... more a b s t r a c t 1 1 Available online xxxx 17 Keywords: 18 Mixed-effects modeling 19 EMT 20 Cellular signaling 21 Correlative networks 22

The World Allergy Organization journal, 2014

A pathological hallmark of asthma is chronic injury and repair, producing dysfunction of the epit... more A pathological hallmark of asthma is chronic injury and repair, producing dysfunction of the epithelial barrier function. In this setting, increased oxidative stress, growth factor- and cytokine stimulation, together with extracellular matrix contact produces transcriptional reprogramming of the epithelial cell. This process results in epithelial-mesenchymal transition (EMT), a cellular state associated with loss of epithelial polarity, expression of mesenchymal markers, enhanced mobility and extracellular matrix remodeling. As a result, the cellular biology of the EMT state produces characteristic changes seen in severe, refractory asthma: myofibroblast expansion, epithelial trans-differentiation and subepithelial fibrosis. EMT also induces profound changes in epithelial responsiveness that affects innate immune signaling that may have impact on the adaptive immune response and effectiveness of glucocorticoid therapy in severe asthma. We discuss how this complex phenotype is beginn...

Clinical and Translational Science, 2015

Multiinstitutional research collaborations now form the most rapid and productive project executi... more Multiinstitutional research collaborations now form the most rapid and productive project execution structures in the health sciences. Effective adoption of a multidisciplinary team research approach is widely accepted as one mechanism enabling rapid translation of new discoveries into interventions in human health. Although the impact of successful team-based approaches facilitating innovation has been well-documented, its utility for training a new generation of scientists has not been thoroughly investigated. We describe the characteristics of how multidisciplinary translational teams (MTTs) promote career development of translational research scholars through competency building, interprofessional integration, and team-based mentoring approaches. Exploratory longitudinal and outcome assessments from our experience show that MTT membership had a positive effect on the development of translational research competencies, as determined by a self-report survey of 32 scholars. We also observed that all trainees produced a large number of collaborative publications that appeared to be associated with their CTSA association and participation with MTTs. We conclude that the MTT model provides a unique training environment for translational and team-based learning activities, for investigators at early stages of career development. Clin Trans Sci 2015; Volume #: 1-9

International review of qualitative research : IRQR, 2013

We apply a symbolic interactionist framework and a qualitative methodology to the examination of ... more We apply a symbolic interactionist framework and a qualitative methodology to the examination of the everyday reality of translational science research (TSR). This is a growing scientific movement that aims to facilitate the efficient application of basic research to clinical service design and delivery. We describe the emerging culture of translational research at a mid-size medical center that received a Clinical and Translational Science Award from the National Institutes of Health. The stories related by scientists, clinicians, and students in interviews indicate that they make sense of the emerging inter- and cross-disciplinary, team-oriented culture of TSR through the refinement and redefinition of the significant symbols that inform their work while they attempt to master translational research by addressing the dilemmas it produces for them and their work. We see the strength, currency, adaptability, and energy of the core self-definition of "scientist" to be signi...

Proteomics, Jan 13, 2015

Despite years of preclinical development, biological interventions designed to treat complex dise... more Despite years of preclinical development, biological interventions designed to treat complex diseases like asthma often fail in phase III clinical trials. These failures suggest that current methods to analyze biomedical data might be missing critical aspects of biological complexity such as the assumption that cases and controls come from homogeneous distributions. Here we discuss why and how methods from the rapidly evolving field of visual analytics can help translational teams (consisting of biologists, clinicians, and bioinformaticians) to address the challenge of modeling and inferring heterogeneity in the proteomic and phenotypic profiles of patients with complex diseases. Because a primary goal of visual analytics is to amplify the cognitive capacities of humans for detecting patterns in complex data, we begin with an overview of the cognitive foundations for the field of visual analytics. Next, we organize the primary ways in which a specific form of visual analytics called...

Journal of immunology (Baltimore, Md. : 1950), 2014

8-Oxoguanine-DNA glycosylase-1 (OGG1) is the primary enzyme for repairing 7,8-dihydro-8-oxoguanin... more 8-Oxoguanine-DNA glycosylase-1 (OGG1) is the primary enzyme for repairing 7,8-dihydro-8-oxoguanine (8-oxoG) via the DNA base excision repair pathway (OGG1-BER). Accumulation of 8-oxoG in the genomic DNA leads to genetic instability and carcinogenesis and is thought to contribute to the worsening of various inflammatory and disease processes. However, the disease mechanism is unknown. In this study, we proposed that the mechanistic link between OGG1-BER and proinflammatory gene expression is OGG1's guanine nucleotide exchange factor activity, acquired after interaction with the 8-oxoG base and consequent activation of the small GTPase RAS. To test this hypothesis, we used BALB/c mice expressing or deficient in OGG1 in their airway epithelium and various molecular biological approaches, including active RAS pulldown, reporter and Comet assays, small interfering RNA-mediated depletion of gene expression, quantitative RT-PCR, and immunoblotting. We report that the OGG1-initiated rep...

Free radical biology & medicine, Jan 19, 2015

Reactive oxygen species inflict oxidative modifications on various biological molecules, includin... more Reactive oxygen species inflict oxidative modifications on various biological molecules, including DNA. One of the most abundant DNA base lesions 8-oxo-7,8-dihydroguanine (8-oxoG) is repaired by 8-oxoguanine DNA glycosylase-1 (OGG1) during DNA base excision repair (OGG1-BER). 8-OxoG accumulation in DNA has been associated with various pathological and aging processes, while its role is unclear. The lack of OGG1-BER in Ogg1-/- mice resulted in decreased inflammatory responses, increased susceptibility to infections and metabolic disorders. Therefore, we proposed that OGG1 and/or 8-oxoG base may have a role in immune and homeostatic processes. To test our hypothesis, we challenged mouse lungs with OGG1-BER product 8-oxoG base and changes in gene expression were determined by RNA sequencing and data were analyzed by gene ontology and statistical tools. RNA-Seq analysis identified 1592 differentially expressed (≥ 3-fold change) transcripts. The upregulated mRNAs were related to biologic...

PLoS ONE, 2012

Background: A series of epidemiologic studies have identified the fungus Alternaria as a major ri... more Background: A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epitheliumderived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation.

PLoS ONE, 2014

We present an integrated dynamical cross-talk model of the epithelial innate immune reponse (IIR)... more We present an integrated dynamical cross-talk model of the epithelial innate immune reponse (IIR) incorporating RIG-I and TLR3 as the two major pattern recognition receptors (PRR) converging on the RelA and IRF3 transcriptional effectors. bioPN simulations reproduce biologically relevant gene-and protein abundance measurements in response to time course, gene silencing and dose-response perturbations both at the population and single cell level. Our computational predictions suggest that RelA and IRF3 are under auto-and cross-regulation. We predict, and confirm experimentally, that RIG-I mRNA expression is controlled by IRF7. We also predict the existence of a TLR3-dependent, IRF3-independent transcription factor (or factors) that control(s) expression of MAVS, IRF3 and members of the IKK family. Our model confirms the observed dsRNA dose-dependence of oscillatory patterns in single cells, with periods of 1-3 hr. Model fitting to time series, matched by knockdown data suggests that the NF-kB module operates in a different regime (with different coefficient values) than in the TNFa-stimulation experiments. In future studies, this model will serve as a foundation for identification of virus-encoded IIR antagonists and examination of stochastic effects of viral replication. Our model generates simulated time series, which reproduce the noisy oscillatory patterns of activity (with 1-3 hour period) observed in individual cells. Our work supports the hypothesis that the IIR is a phenomenon that emerged by evolution despite highly variable responses at an individual cell level.

Oncogene, 2001

In chronic myelogenous leukemia (CML), the oncogene bcr-abl encodes a dysregulated tyrosine kinas... more In chronic myelogenous leukemia (CML), the oncogene bcr-abl encodes a dysregulated tyrosine kinase that inhibits apoptosis. We showed previously that human erythroleukemia K562 cells are resistant to antineoplastic drug (taxol)-induced apoptosis through the atypical protein kinase C iota isozyme (PKCι), a kinase downstream of Bcr-Abl. The mechanism(s) by which PKCι mediates cell survival to taxol is unknown. Here we demonstrate that PKCι requires the transcription factor nuclear factor-κB (NF-κB) to confer cell survival. At apoptosis-inducing concentrations, taxol weakly induces IκBα proteolysis and NF-κB translocation in K562 cells, but potently induces its transcriptional activity. Inhibition of NF-κB activity (by blocking IκBα degradation) significantly sensitizes cells to taxol-induced apoptosis. Likewise, K562 cells expressing antisense PKCι mRNA or kinase dead PKCι (PKCι-KD) are sensitized to taxol; these cells are rescued from apoptosis by NF-κB overexpression. Expression of constitutively active PKCι (PKCι-CA) upregulates NF-κB transactivation and rescues cells from apoptosis in the absence of Bcr-Abl tyrosine kinase activity. Using a chimeric GAL4-RelA transactivator, we find that taxol potently activates GAL4-RelA-dependent transcription. This activation was further upregulated by expression of PKCι-CA and inhibited by expression of PKCι-KD. Our results indicate that RelA transactivation is an important downstream target of the PKCι-mediated Bcr-Abl signaling pathway and is required for resistance to taxol-induced apoptosis.

Molecular Endocrinology, 2007

Kidney International, 1994

Transcripting factors modulating angiotensinogen gene expression in hepatocytes. The gene encodin... more Transcripting factors modulating angiotensinogen gene expression in hepatocytes. The gene encoding angiotensinogen is regulated at the transcriptional level in hepatocytes in response to glucocorticoids and inflammatory cytokines (IL-i and TNF). These hormones activate transcription of the angiotensinogen gene by changing the abundance of DNA binding proteins that interact with a multihormone-inducible enhancer located between nucleotides -615 to -440 upstream of the major transcription start site. Activation of this enhancer in hepatocytes is effected by glucocorticoid-and cytokine-inducible DNA binding proteins. Cytokine induction is mediated through the interaction of two classes of transcription factors that bind to the acute-phase response element (APRE): nuclear factor-KB (NF-B), and CCAAT-Box/Enhancer Binding Protein (C/EBP). NF-KB is a multiprotein DNA binding complex sequestered in the cytoplasm that is induced in the nucleus by cytokines, whereas C/EBP is a nuclear transcription factor family implicated in the expression of differentiated hepatic proteins. During the acute-phase response, individual C/EBP family members are discordinately regulated: C/EBPa levels fall, whereas another CIEBP family member termed nuclear factor 1L6 (NF-1L6), is induced. We investigated the interaction between the two acute-phase induced APRE-binding proteins: NF-KB and NF-1L6. Both proteins bind to overlapping nucleotides in a mutually exclusive fashion with similar affinities for the APRE. NF-1L6, a less potent transactivator, attenuates NF-KB mediated transcription late in the evolution of the acute-phase response. These observations argue for a temporal model of sequentially-expressed transcription factors occupying the APRE during the evolution of the inflammatory process.

Journal of Virology, 2005

Journal of Virology, 2003

RSV replication is a potent activator of the epithelial-cell genomic response, influencing the ex... more RSV replication is a potent activator of the epithelial-cell genomic response, influencing the expression of a spectrum of cellular pathways, including proinflammatory chemokines of the CC, CXC, and CX 3 C subclasses. Ribavirin (1-␤-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a nontoxic antiviral agent currently licensed for the treatment of severe RSV lower respiratory tract infections. Because ribavirin treatment reduces the cytopathic effect in infected cells, we used high-density microarrays to investigate the hypothesis that ribavirin modifies the virus-induced epithelial genomic response to replicating virus. Ribavirin treatment administered in concentrations of 10 to 100 g/ml potently inhibited RSV transcription, thereby reducing the level of RSV N transcripts to ϳ13% of levels in nontreated cells. We observed that in both the absence and the presence of ribavirin, RSV infection induced global alterations in the host epithelial cell, affecting ϳ49% of the ϳ6,650 expressed genes detectable by the microarray. , complement products, acute-phase response factors, and the STAT and IRF transcription factors. Because IFN-␤ expression itself was reduced in the ribavirin-treated cells, we further investigated the mechanism for up-regulation of the IFN-signaling pathway. Enhanced expression of IFI 6-16, IFI 9-27, MxA/p78, STAT-1␣, STAT-1␤, IRF-7B, and TAP-1-LMP2 transcripts were independently reproduced by Northern blot analysis. Ribavirin-enhanced TAP-1-LMP2 expression was a transcriptional event where site mutations of the IFN-stimulated response element (ISRE) blocked RSV and ribavirin-inducible promoter activity. Furthermore, ribavirin up-regulated the transcriptional activity of a reporter gene selectively driven by the ISRE. In specific DNA pull-down assays, we observed that ribavirin enhanced RSV-induced STAT-1 binding to the ISRE. We conclude that ribavirin potentiates virus-induced ISRE signaling to enhance the expression of antiviral ISGs, suggesting a mechanism for the efficacy of combined treatment with ribavirin and IFN in other chronic viral diseases.

Journal of Virology, 2005

signaling pathways by complexing with them and recruiting HDAC-1 to attenuate target promoter act... more signaling pathways by complexing with them and recruiting HDAC-1 to attenuate target promoter activity.

The Journal of Immunology, 2014

Journal of Allergy and Clinical Immunology, 2008

Background-Asthma is a heterogeneous clinical disorder. Methods for objective identification of d... more Background-Asthma is a heterogeneous clinical disorder. Methods for objective identification of disease subtypes will focus on clinical interventions and help identify causative pathways. Few studies have explored phenotypes at a molecular level.

Gastroenterology, 2004

Background & Aims: Gastric mucosal interleukin (IL)-8 levels are related to the presence of both ... more Background & Aims: Gastric mucosal interleukin (IL)-8 levels are related to the presence of both the cag pathogenicity island (PAI) and OipA. We investigated the regions of the IL-8 promoter and the upstream signaling involved in IL-8 gene transcription. Methods: We cocultured parental Helicobacter pylori and isogenic oipA, hopZ, or cagE gene knockout mutants with gastric cancer cells. The regulatory sites in the IL-8 promoter were examined by luciferase reporter gene assay, electrophoretic mobility shift assays, and immunoblot analyses. Phosphorylated signal transducers and activators of transcription 1 (STAT1) levels in the antral gastric mucosa were measured by enzyme-linked immunosorbent assay. Results: Maximal H. pylori-induced IL-8 gene transcription required the presence of the interferon-stimulated responsive element (ISRE)-like element, nuclear factor (NF)-B and activator protein (AP)-1 binding sites. In vitro studies showed that OipA and the cag PAI were involved in inducing interferon regulatory factor (IRF)-1 to bind and activate the ISRE-like element and that the cag PAI, but not OipA, was involved in activating AP-1 and NF-B. Both in vitro and in vivo studies showed that OipA, but not the cag PAI, was involved in STAT1 phosphorylation, as upstream signaling of IRF-1. Conclusions: OipA and the cag PAI are both necessary for full activation of the IL-8 promoter but act via different pathways that diverge upstream of IRF-1 where only OipA is involved in the STAT1-IRF1-ISRE pathway. The mucosal inflammatory response to H. pylori infection is complex and involves different pathways converging on the IL-8 promoter.

Free Radical Biology and Medicine, 2014

The user has requested enhancement of the downloaded file. All in-text references underlined in b... more The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

American Journal of Tropical Medicine and Hygiene, 2012

Cellular Signalling, 2015

a b s t r a c t 1 1 Available online xxxx 17 Keywords: 18 Mixed-effects modeling 19 EMT 20 Cellul... more a b s t r a c t 1 1 Available online xxxx 17 Keywords: 18 Mixed-effects modeling 19 EMT 20 Cellular signaling 21 Correlative networks 22

The World Allergy Organization journal, 2014

A pathological hallmark of asthma is chronic injury and repair, producing dysfunction of the epit... more A pathological hallmark of asthma is chronic injury and repair, producing dysfunction of the epithelial barrier function. In this setting, increased oxidative stress, growth factor- and cytokine stimulation, together with extracellular matrix contact produces transcriptional reprogramming of the epithelial cell. This process results in epithelial-mesenchymal transition (EMT), a cellular state associated with loss of epithelial polarity, expression of mesenchymal markers, enhanced mobility and extracellular matrix remodeling. As a result, the cellular biology of the EMT state produces characteristic changes seen in severe, refractory asthma: myofibroblast expansion, epithelial trans-differentiation and subepithelial fibrosis. EMT also induces profound changes in epithelial responsiveness that affects innate immune signaling that may have impact on the adaptive immune response and effectiveness of glucocorticoid therapy in severe asthma. We discuss how this complex phenotype is beginn...