Modulation of lung inflammation by the Epstein-Barr virus protein Zta

Abstract

Several studies have implicated gamma-herpesviruses, particularly Epstein-Barr virus (EBV), in the progression of idiopathic pulmonary fibrosis. The data presented here examine the possible role that EBV plays in the potentiation of this disease by evaluating the pulmonary response to expression of the EBV lytic transactivator protein Zta. Expression of Zta in the lungs of mice via adenovirus-mediated delivery (Adv-Zta) produced profibrogenic inflammation that appeared most pronounced by day 7 postexposure. Relative to mice exposed to control GFP-expressing adenovirus (Adv-GFP), mice exposed to Adv-Zta displayed evidence of lung injury and a large increase in inflammatory cells, predominantly neutrophils, recovered by bronchoalveolar lavage (BAL). Cytokine and mRNA profiling of the BAL fluid and cells recovered from Adv-Zta-treated mice revealed a Th2 and Th17 bias. mRNA profiles from Adv-Zta-infected lung epithelial cells revealed consistent induction of mRNAs encoding Th2 cytokines. Coexpression in transient assays of wild-type Zta, but not a DNA-binding-defective mutant Zta, activated expression of the IL-13 promoter in lung epithelial cells, and detection of IL-13 in Adv-Zta-treated mice correlated with expression of Zta. Induction of Th2 cytokines in Zta-expressing mice corresponded with alternative activation of macrophages. In cell culture and in mice, Zta repressed lung epithelial cell markers. Despite the profibrogenic character at day 7, the inflammation resolves by 28 days postexposure to Adv-Zta without evidence of fibrosis. These observations indicate that the EBV lytic transactivator protein Zta displays activity consistent with a pathogenic role in pulmonary fibrosis associated with herpesvirus infection.

Epstein-Barr Virus BZLF1-Mediated Downregulation of Proinflammatory Factors Is Essential for Optimal Lytic Viral Replication

“…However, the pattern of inflammatory factors is altered following the switch from the latent EBV life cycle to the lytic life cycle. Previous studies have shown that BZLF1 regulates inflammation (10,48), and our present study provided new evidence indicating that BZLF1 attenuates TNF-␣ and IFN-␥ expression as well as expression of a series of other inflammatory factors. In addition, BZLF1 abolishes the response to TNF-␣ and IFN-␥ stimuli by inhibiting the expression of the major TNF receptor TNFR1 and the IFN-␥ receptor, respectively (21)(22)(23).…”

MTBP plays a crucial role in mitotic progression and chromosome segregation

“…38,39 To detect kinetochore MTBP, H-40 antibody (Santa Cruz Biotechnology) was used. Z-sectioned images were obtained on a Zeiss Axioplan II deconvolution microscope (Carl Zeiss, Thornwood, NY, USA) and processed as described by Guenther et al 40 Flow cytometric analysis. For cell cycle analysis, cells fixed with 70% ethanol at À201C were stained with PI solution (Invitrogen) in the presence of 10 mg/ml RNase, followed by flow cytometric analysis using FACSCalibur (BD Biosciences).…”

Promotion of lung tumor growth by interleukin-17

“…After three washes with 3% BSA in PBS, the sections were incubated with streptavidinconjugated horseradish peroxidase (1:2,000 dilution) (016-030-084; Jackson ImmunoResearch Laboratories) in the same solution for 1 h at room temperature. Visualization with diaminobenzidine and counterstaining were as previously described (17).…”

“…Bronchoalveolar lavage (BAL) was performed after intubation of mice with a 20-gauge 1.25-in. catheter secured in place with a suture (17). Mice were lavaged with 5 ϫ 0.8 ml of ice-cold lavage buffer (0.137 M sodium chloride, 2.7 mM potassium chloride, 12 mM phosphate buffer, 0.4 mM EDTA, pH 7.4).…”

“…This route of delivery produces expression of the transduced gene in epithelial cells throughout the lung (17). For control purposes, an equivalent amount of AdV-GFP was delivered to littermates.…”