Involvement of fatty acid synthase in dengue virus infection

  • PDF / 8,361,037 Bytes
  • 18 Pages / 595.276 x 790.866 pts Page_size
  • 83 Downloads / 185 Views

DOWNLOAD

REPORT


RESEARCH

Open Access

Involvement of fatty acid synthase in dengue virus infection Natthida Tongluan1, Suwipa Ramphan1, Phitchayapak Wintachai1, Janthima Jaresitthikunchai2, Sarawut Khongwichit1, Nitwara Wikan1, Supoth Rajakam1, Sutee Yoksan1,3, Nuttaporn Wongsiriroj1, Sittiruk Roytrakul2 and Duncan R. Smith1,3*

Abstract Background: The mosquito transmitted Dengue virus (DENV) remains a significant public health problem in many tropical and subtropical countries. Increasing evidence has suggested that during the infection process cellular lipids play important roles at several stages of the replication cycle. This study sought to characterize the changes in lipid metabolism gene expression and investigated the role of one enzyme, fatty acid synthase, in DENV infection. Methods: Transcriptional profiles of genes associated with lipid metabolism were evaluated by real-time PCR after infection of different cell lines (HepG2 and HEK293T/17) and with different DENVs (laboratory adapted and low passage). Expression profiles of genes were evaluated by western blotting. A critical lipid metabolism protein, fatty acid synthase was down-regulated through siRNA and inhibited with orlistat and the effect on DENV infection determined by flow cytometry, plaque assay, western blotting and confocal microscopy. Results: The results showed alterations of gene transcription and expression were seen in genes variously associated with lipogenesis, lipolysis and fatty acid β-oxidation during DENV infection. Interference of fatty acid synthase with either siRNA or orlistat had marked effects on virus production, with orlistat having an EC50 value of 10.07 μM at 24 h post infection. However, non-structural protein expression was largely unaffected. Conclusions: While drug treatment reduced virus titer by up to 3Log10, no significant effect on DENV non-structural protein expression was observed, suggesting that fatty acid synthase acts through an effect on virion formation. Keywords: Dengue, Lipid, non-structural protein 3, Fatty acid synthase, Orlistat

Background Each year there are believed to be nearly 400 million new Dengue virus (DENV) infections in tropical and sub-tropical countries worldwide, of which some 100 million show some form of symptom [1]. The mosquito transmitted DENV infects humans after the bite of an infected female Aedes mosquito, and where symptoms occur these can range from a mild flu-like illness to a severe life threatening syndrome primarily characterized by plasma leakage [2]. DENV is largely maintained in an urban transmission cycle, with the anthropophilic Aedes * Correspondence: [email protected] 1 Molecular Pathology Laboratory, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, 25/25 Phuttamonthon Sai 4, Salaya, Nakhon Pathom, Bangkok 73170, Thailand 3 Center for Emerging and Neglected Infectious Diseases, Mahidol University, Nakhon Pathom, Bangkok 73170, Thailand Full list of author information is available at the end of the article

aegypti being the primary vector [3]. DEN