Oxygen-Independent Stabilization of Hypoxia Inducible Factor HIF-1 during RSV InfectionReportar como inadecuado




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Background

Hypoxia-inducible factor 1 HIF-1α is a transcription factor that functions as master regulator of mammalian oxygen homeostasis. In addition, recent studies identified a role for HIF-1α as transcriptional regulator during inflammation or infection. Based on studies showing that respiratory syncytial virus RSV is among the most potent biological stimuli to induce an inflammatory milieu, we hypothesized a role of HIF-1α as transcriptional regulator during infections with RSV.

Methodology, Principal Findings

We gained first insight from immunohistocemical studies of RSV-infected human pulmonary epithelia that were stained for HIF-1α. These studies revealed that RSV-positive cells also stained for HIF-1α, suggesting concomitant HIF-activation during RSV infection. Similarly, Western blot analysis confirmed an approximately 8-fold increase in HIF-1α protein 24 h after RSV infection. In contrast, HIF-1α activation was abolished utilizing UV-treated RSV. Moreover, HIF-α-regulated genes VEGF, CD73, FN-1, COX-2 were induced with RSV infection of wild-type cells. In contrast, HIF-1α dependent gene induction was abolished in pulmonary epithelia following siRNA mediated repression of HIF-1α. Measurements of the partial pressure of oxygen in the supernatants of RSV infected epithelia or controls revealed no differences in oxygen content, suggesting that HIF-1α activation is not caused by RSV associated hypoxia. Finally, studies of RSV pneumonitis in mice confirmed HIF-α-activation in a murine in vivo model.

Conclusions-Significance

Taking together, these studies suggest hypoxia-independent activation of HIF-1α during infection with RSV in vitro and in vivo.



Autor: Helene A. Haeberle , Carin Dürrstein , Peter Rosenberger, Yashoda M. Hosakote, Johannes Kuhlicke, Volkhard A. J. Kempf, Roberto

Fuente: http://plos.srce.hr/



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