Publications by authors named "Tracy Zimmerman"

At a time when people are losing faith in public institutions, trust in the North Carolina Department of Health and Human Services is high. Using North Carolina's pandemic journey as a communication case study offers lessons for public health leaders. This article shares communication elements that helped build trust and provides recommendations.

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Hereditary angioedema (HAE) is a genetic disorder mostly caused by mutations in the C1 esterase inhibitor gene (C1INH) that results in poor control of contact pathway activation and excess bradykinin generation. Bradykinin increases vascular permeability and is ultimately responsible for the episodes of swelling characteristic of HAE. We hypothesized that the use of RNA interference (RNAi) to reduce plasma Factor XII (FXII), which initiates the contact pathway signaling cascade, would reduce contact pathway activation and prevent excessive bradykinin generation.

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Phytosterols, components of soy-derived lipids, are among the proposed exacerbants of parenteral nutrition-associated cholestasis (PNAC). We investigated whether phytosterols contribute to bile acid (BA)-induced hepatocyte damage by antagonizing a nuclear receptor (NR) critically involved in hepatoprotection from cholestasis, FXR (farnesoid X receptor, NR1H4). In HepG2 cells, stigmasterol acetate (StigAc), a water-soluble Stig derivative, suppressed ligand-activated expression of FXR target genes involved in adaptation to cholestasis (i.

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As the obligate heterodimer partner to class II nuclear receptors, the retinoid X receptor alpha (RXRalpha) plays a vital physiological role in the regulation of multiple hepatic functions, including bile formation, intermediary metabolism, and endobiotic/xenobiotic detoxification. Many RXRalpha-regulated genes are themselves suppressed in inflamed liver via unknown mechanisms, which constitute a substantial component of the negative hepatic acute phase response. In this study we show that RXRalpha, generally considered a stable nuclear resident protein, undergoes rapid nuclear export in response to signals initiated by the pro-inflammatory cytokine interleukin-1beta (IL-1beta), a central activator of the acute phase response.

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BACKGROUND: Lipopolysaccharide (LPS) treatment of animals down-regulates the expression of hepatic genes involved in a broad variety of physiological processes, collectively known as the negative hepatic acute phase response (APR). Retinoid X receptor alpha (RXRalpha), the most highly expressed RXR isoform in liver, plays a central role in regulating bile acid, cholesterol, fatty acid, steroid and xenobiotic metabolism and homeostasis. Many of the genes regulated by RXRalpha are repressed during the negative hepatic APR, although the underlying mechanism is not known.

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Partial hepatectomy leads to an orchestrated regenerative response, activating a cascade of cell signaling events necessary for cell cycle progression and proliferation of hepatocytes. However, the identity of the humoral factors that trigger the activation of these pathways in the concerted regenerative response in hepatocytes remains elusive. In recent years, extracellular ATP has emerged as a rapidly acting signaling molecule that influences a variety of liver functions, but its role in hepatocyte growth and regeneration is unknown.

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Bile flow is rapidly and markedly reduced in hepatic inflammation, correlating with suppression of critical hepatic bile acid transporter gene expression, including the principal hepatic bile acid importer, the Na(+)/taurocholate co-transporting polypeptide (Ntcp, Slc10a1). Endotoxin treatment of rats and interleukin-1 beta (IL-1 beta) treatment of liver-derived HepG2 cells leads to a marked decline in the nuclear binding activity of a main Ntcp gene regulator, the nuclear receptor heterodimer retinoid X receptor:retinoic acid receptor (RXR:RAR). How IL-1 beta signaling leads to reduced RXR:RAR nuclear binding activity is unknown, and we sought to determine whether mitogen-activated protein kinase (MAPK) pathways were involved.

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Cytosolic and nuclear Ca(2+) have been shown to differentially regulate transcription. However, the impact of spatially distinct Ca(2+) signals on mitogen-activated protein kinase-mediated gene expression remains unknown. Here we investigated the role of nuclear and cytosolic Ca(2+) signals in epidermal growth factor (EGF)-induced transactivation of the ternary complex factor Elk-1 using a GAL4-Elk-1 construct.

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