Publications

Regulation of Gene Expression by Posttranslational Modification of Transcription Factors

Protein Phosphatase 2A Potentiates Activity of Promoters Containing AP-1-Binding Elements

The involvement of serine/threonine protein phosphatases in signaling pathways which modulate the activity of the transcription factor AP-1 was examined. Purified protein phosphatase types 1 (PP1) and 2A (PP2A) were microinjected into cell lines containing stably transfected lacZ marker genes under the control of an enhancer recognized by AP-1. Microinjection of PP2A potentiated serum-stimulated beta-galactosidase expression from the AP-1-regulated promoter. Similarly, transient expression of the PP2A catalytic subunit with c-Jun resulted in a synergistic transactivation of an AP-1-regulated reporter gene. PP2A, but not PP1, potentiated serum-induced c-Jun expression, which has been previously shown to be autoregulated by AP-1 itself. Consistent with these results, PP2A dephosphorylated c-Jun on negative regulatory sites in vitro, suggesting one possible direct mechanism for the effects of PP2A on AP-1 activity. Microinjection of PP2A had no effect on cyclic AMP (cAMP)-induced expression of a reporter gene containing a cAMP-regulated promoter, while PP1 injection abolished cAMP-induced gene expression. Taken together, these results suggest a specific role for PP2A in signal transduction pathways that regulate AP-1 activity and c-Jun expression.

Detection of in vivo ubiquitinated protein

Hepatic Expression of HCV RNA-Dependent RNA Polymerase Triggers Innate Immune Signaling and Cytokine Production

Physical Activity 2 Correlates of physical activity: why are some people physically active and others not?

Physical inactivity is an important contributor to non-communicable diseases in countries of high income, and increasingly so in those of low and middle income. Understanding why people are physically active or inactive contributes to evidence-based planning of public health interventions, because eff ective programmes will target factors known to cause inactivity. Research into correlates (factors associated with activity) or determinants (those with a causal relationship) has burgeoned in the past two decades, but has mostly focused on individual-level factors in high-income countries. It has shown that age, sex, health status, self-effi cacy, and motivation are associated with physical activity. Ecological models take a broad view of health behaviour causation, with the social and physical environment included as contributors to physical inactivity, particularly those outside the health sector, such as urban planning, transportation systems, and parks and trails. New areas of determinants research have identifi ed genetic factors contributing to the propensity to be physically active, and evolutionary factors and obesity that might predispose to inactivity, and have explored the longitudinal tracking of physical activity throughout life. An understanding of correlates and determinants, especially in countries of low and middle income, could reduce the eff ect of future epidemics of inactivity and contribute to eff ective global prevention of non-communicable diseases.

Data from Macrophage Expression of Hypoxia-Inducible Factor-1α Suppresses T-Cell Function and Promotes Tumor Progression

<div>Abstract<p>T cells can inhibit tumor growth, but their function in the tumor microenvironment is often suppressed. Many solid tumors exhibit abundant macrophage infiltration and low oxygen tension, yet how hypoxic conditions may affect innate immune cells and their role in tumor progression is poorly understood. Targeted deletion of the hypoxia-responsive transcription factor hypoxia-inducible factor-1α (HIF-1α) in macrophages in a progressive murine model of breast cancer resulted in reduced tumor growth, although vascular endothelial growth factor-A levels and vascularization were unchanged. Tumor-associated macrophages can suppress tumor-infiltrating T cells by several mechanisms, and we found that hypoxia powerfully augmented macrophage-mediated T-cell suppression <i>in vitro</i> in a manner dependent on macrophage expression of HIF-1α. Our findings link the innate immune hypoxic response to tumor progression through induction of T-cell suppression in the tumor microenvironment. Cancer Res; 70(19); 7465–75. ©2010 AACR.</p></div>

How Health and Fitness Professionals Can Further Advance the Nation's Health by Working Across the Ecological Model

Apply It! From this article, readers should: • Identify how health and fitness professionals can promote health and wellness among their fitness center, health club, or gym members, clients, patients, and communities by working collaboratively with colleagues across multiple levels of an ecological model. • Understand how using evidence-based intervention approaches recommended by the Community Preventive Services Task Force may enhance the effect of health and fitness professionals on increasing physical activity. • Learn why it's important to help create physical activity-friendly communities and how they can help support fitness centers, health clubs, or gyms and the efforts of members, clients, or patients to be more physically active in and out of health and fitness facilities. • Identify ways to take action in their community in support of Active People, Healthy Nation sm , CDC's national initiative to increase physical activity, by creating and contributing to equitable policy, systems, and environmental changes to support active lifestyles and decrease physical inactivity.

Studies of the Mechanism of Glucocorticoid Hormone Action

The Pore-Forming Toxin β hemolysin/cytolysin Triggers p38 MAPK-Dependent IL-10 Production in Macrophages and Inhibits Innate Immunity

Group B Streptococcus (GBS) is a leading cause of invasive bacterial infections in human newborns and immune-compromised adults. The pore-forming toxin (PFT) β hemolysin/cytolysin (βh/c) is a major virulence factor for GBS, which is generally attributed to its cytolytic functions. Here we show βh/c has immunomodulatory properties on macrophages at sub-lytic concentrations. βh/c-mediated activation of p38 MAPK drives expression of the anti-inflammatory and immunosuppressive cytokine IL-10, and inhibits both IL-12 and NOS2 expression in GBS-infected macrophages, which are critical factors in host defense. Isogenic mutant bacteria lacking βh/c fail to activate p38-mediated IL-10 production in macrophages and promote increased IL-12 and NOS2 expression. Furthermore, targeted deletion of p38 in macrophages increases resistance to invasive GBS infection in mice, associated with impaired IL-10 induction and increased IL-12 production in vivo. These data suggest p38 MAPK activation by βh/c contributes to evasion of host defense through induction of IL-10 expression and inhibition of macrophage activation, a new mechanism of action for a PFT and a novel anti-inflammatory role for p38 in the pathogenesis of invasive bacterial infection. Our studies suggest p38 MAPK may represent a new therapeutic target to blunt virulence and improve clinical outcome of invasive GBS infection.

Myeloid IKKβ Promotes Antitumor Immunity by Modulating CCL11 and the Innate Immune Response

Myeloid cells are capable of promoting or eradicating tumor cells and the nodal functions that contribute to their different roles are still obscure. Here, we show that mice with myeloid-specific genetic loss of the NF-κB pathway regulatory kinase IKKβ exhibit more rapid growth of cutaneous and lung melanoma tumors. In a BRAF(V600E/PTEN(-/-)) allograft model, IKKβ loss in macrophages reduced recruitment of myeloid cells into the tumor, lowered expression of MHC class II molecules, and enhanced production of the chemokine CCL11, thereby negatively regulating dendritic-cell maturation. Elevated serum and tissue levels of CCL11 mediated suppression of dendritic-cell differentiation/maturation within the tumor microenvironment, skewing it toward a Th2 immune response and impairing CD8(+) T cell-mediated tumor cell lysis. Depleting macrophages or CD8(+) T cells in mice with wild-type IKKβ myeloid cells enhanced tumor growth, where the myeloid cell response was used to mediate antitumor immunity against melanoma tumors (with less dependency on a CD8(+) T-cell response). In contrast, myeloid cells deficient in IKKβ were compromised in tumor cell lysis, based on their reduced ability to phagocytize and digest tumor cells. Thus, mice with continuous IKKβ signaling in myeloid-lineage cells (IKKβ(CA)) exhibited enhanced antitumor immunity and reduced melanoma outgrowth. Collectively, our results illuminate new mechanisms through which NF-κB signaling in myeloid cells promotes innate tumor surveillance.

Validity of the Global Physical Activity Questionnaire (GPAQ) in assessing levels and change in moderate-vigorous physical activity and sedentary behaviour

Feasible, cost-effective instruments are required for the surveillance of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) and to assess the effects of interventions. However, the evidence base for the validity and reliability of the World Health Organisation-endorsed Global Physical Activity Questionnaire (GPAQ) is limited. We aimed to assess the validity of the GPAQ, compared to accelerometer data in measuring and assessing change in MVPA and SB. Participants (n = 101) were selected randomly from an on-going research study, stratified by level of physical activity (low, moderate or highly active, based on the GPAQ) and sex. Participants wore an accelerometer (Actigraph GT3X) for seven days and completed a GPAQ on Day 7. This protocol was repeated for a random sub-sample at a second time point, 3–6 months later. Analysis involved Wilcoxon-signed rank tests for differences in measures, Bland-Altman analysis for the agreement between measures for median MVPA and SB mins/day, and Spearman's rho coefficient for criterion validity and extent of change. 95 participants completed baseline measurements (44 females, 51 males; mean age 44 years, (SD 14); measurements of change were calculated for 41 (21 females, 20 males; mean age 46 years, (SD 14). There was moderate agreement between GPAQ and accelerometer for MVPA mins/day (r = 0.48) and poor agreement for SB (r = 0.19). The absolute mean difference (self-report minus accelerometer) for MVPA was −0.8 mins/day and 348.7 mins/day for SB; and negative bias was found to exist, with those people who were more physically active over-reporting their level of MVPA: those who were more sedentary were less likely to under-report their level of SB. Results for agreement in change over time showed moderate correlation (r = 0.52, p = 0.12) for MVPA and poor correlation for SB (r = −0.024, p = 0.916). Levels of agreement with objective measurements indicate the GPAQ is a valid measure of MVPA and change in MVPA but is a less valid measure of current levels and change in SB. Thus, GPAQ appears to be an appropriate measure for assessing the effectiveness of interventions to promote MVPA.

A YAP/TAZ-induced feedback mechanism regulates Hippo pathway homeostasis

YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif) are major downstream effectors of the Hippo pathway that influences tissue homeostasis, organ size, and cancer development. Aberrant hyperactivation of YAP/TAZ causes tissue overgrowth and tumorigenesis, whereas their inactivation impairs tissue development and regeneration. Dynamic and precise control of YAP/TAZ activity is thus important to ensure proper physiological regulation and homeostasis of the cells. Here, we show that YAP/TAZ activation results in activation of their negative regulators, LATS1/2 (large tumor suppressor 1/2) kinases, to constitute a negative feedback loop of the Hippo pathway in both cultured cells and mouse tissues. YAP/TAZ in complex with the transcription factor TEAD (TEA domain family member) directly induce LATS2 expression. Furthermore, YAP/TAZ also stimulate the kinase activity of LATS1/2 through inducing NF2 (neurofibromin 2). This feedback regulation is responsible for the transient activation of YAP upon lysophosphatidic acid (LPA) stimulation and the inhibition of YAP-induced cell migration. Thus, this LATS-mediated feedback loop provides an efficient mechanism to establish the robustness and homeostasis of YAP/TAZ regulation.

Disruption of JNK2 Decreases the Cytokine Response to <i>Plasmodium falciparum</i> Glycosylphosphatidylinositol In Vitro and Confers Protection in a Cerebral Malaria Model

Host inflammatory responses to Plasmodium falciparum GPI (pfGPI) anchors are believed to play an important role in the pathophysiology of severe malaria. However, relatively little is known about the signal transduction pathways involved in pfGPI-stimulated inflammatory response and its potential contribution to severe malaria syndromes. In this study, we investigated the role of MAPK activation in pfGPI-induced cytokine secretion and examined the role of selected MAPKs in a model of cerebral malaria in vivo. We demonstrate that ERK1/2, JNK, p38, c-Jun, and activating transcription factor-2 became phosphorylated in pfGPI-stimulated macrophages. A JNK inhibitor (1,9-pyrazoloanthrone) inhibited pfGPI-induced phosphorylation of JNK, c-Jun, and activating transcription factor-2 and significantly decreased pfGPI-induced TNF-alpha secretion. pfGPI-stimulated JNK and c-Jun phosphorylation was absent in Jnk2(-/-) macrophages but unchanged in Jnk1(-/-) and Jnk3(-/-) macrophages compared with wild-type macrophages. Jnk2(-/-) macrophages secreted significantly less TNF-alpha in response to pfGPI than macrophages from Jnk1(-/-), Jnk3(-/-), and wild-type counterparts. Furthermore, we demonstrate a role for JNK2 in mediating inflammatory responses and severe malaria in vivo. In contrast to wild-type or Jnk1(-/-) mice, Jnk2(-/-) mice had lower levels of TNF-alpha in vivo and exhibited significantly higher survival rates when challenged with Plasmodium berghei ANKA. These results provide direct evidence that pfGPI induces TNF-alpha secretion through activation of MAPK pathways, including JNK2. These results suggest that JNK2 is a potential target for therapeutic interventions in severe malaria.

The role of RANK-signaling in breast cancer development and metastasis

4200 RANK (Receptor Activator of NFκB) is a member of TNFα receptor super family. RANKL (RANK Ligand) activates RANK and its down-stream kinase IKKα, controlling osteoclast differentiation, mammary gland development as well as breast cancer tumorigenesis. Inhibition of RANK leads to reduction in tumor colonization and growth in bones in several mouse tumor metastasis models. However, the underlying mechanism underlying is still largely unknown. The purpose of the current study is to monitor and understand the influence of RANK-signaling on step-wise tumor development and metastasis. We used orthotopic tumor transplantation models with green fluorescent protein (GFP) and red fluorescent protein (DsRed2)-labeled Her2/neu transformed tumor cells which are under the control of RANK signaling. With the aid of real-time fluorescence imaging we can measure tumor growth, and monitor invasion, trafficking and colonization of tumor cells in real-time. To understand the mechanisms involved, we employed Western-blotting, RT-PCR, cell fractionation and transient transfection reporter assays. We found RANKL stimulation increased the nuclear accumulation of IKKα and expression of a group of genes involved in inflammation. However, genes which control the cell cycle and proliferation remained unchanged. This observation is consistent with that RANKL stimulation does not influence tumor-cell proliferation tumor growth. It is of great importance to analyze how blockage of RANK and RANK down-stream effectors, including IKKα and responsive genes affect tumor behavior and tumor-host interaction.

Longitudinal measurement invariance of psychosocial measures in physical activity research: an application to adolescent data

The current study served as a practical and substantive guide to establishing longitudinal measurement invariance of psychosocial measures commonly used in adolescent physical activity (PA) research. Psychosocial data on an initial sample of 878 adolescents (ages 11 - 15) recruited through primary care providers were provided at baseline, 6, 12, and 24 months. The target measures included family support, peer support, decisional balance (pros, cons), self-efficacy, and behavioral strategies. Five of the six psychosocial measures exhibited strict longitudinal measurement invariance, with the 6th measure (self-efficacy) exhibiting strong longitudinal measurement invariance. These findings support the equivalence of these measures across time, and provide the foundation to substantively interpret group differences and associations involving these measures and PA.

Cruel to Be Kind: Epithelial, Microbial, and Immune Cell Interactions in Gastrointestinal Cancers

A plethora of experimental and epidemiological evidence supports a critical role for inflammation and adaptive immunity in the onset of cancer and in shaping its response to therapy. These data are particularly robust for gastrointestinal (GI) cancers, such as those affecting the GI tract, liver, and pancreas, on which this review is focused. We propose a unifying hypothesis according to which intestinal barrier disruption is the origin of tumor-promoting inflammation that acts in conjunction with tissue-specific cancer-initiating mutations. The gut microbiota and its products impact tissue-resident and recruited myeloid cells that promote tumorigenesis through secretion of growth- and survival-promoting cytokines that act on epithelial cells, as well as fibrogenic and immunosuppressive cytokines that interfere with the proper function of adaptive antitumor immunity. Understanding these relationships should improve our ability to prevent cancer development and stimulate the immune system to eliminate existing malignancies.

Global Problems Require Global Studies

No abstract is provided for this article.

Home Food Environment Associations with Children's Dietary Intake and Weight Status

No abstract is provided for this article.