title: XAF1 contributes to dengue virus-induced apoptosis in vascular endothelial cells.
abstract: The mechanism of vascular leakage in severe dengue infection remains unclear. Here, we used primary human umbilical vein endothelial cells (HUVECs) and the EA.hy926 cell line to study the molecular events that occur after dengue virus serotype 2 (DENV2) infection. DENV2-induced apoptosis was confirmed using nuclear staining, TUNEL assay, and electron microscopy. A genome-wide transcriptome analysis was performed using a microarray of DENV2-infected HUVECs. Notably, interferon-inducible genes were differentially expressed after DENV2 infection. Prominent among these genes was the X chromosome-linked inhibitor of apoptosis protein (XIAP)-associated factor 1 (XAF1; up-regulated 1.2-fold in the microarray analysis and ∼8-fold by qRT-PCR after DENV2 infection). XAF1 protein levels were up-regulated after DENV2 infection in both HUVECs and EA.hy926 cells. Evidence indicated interaction between XAF1 and XIAP during DENV2 infection based on their cellular localization, as observed by confocal microscopy and the coimmunoprecipitation of XIAP with an anti-XAF1 antibody. Next, recombinant EA.hy926 cell lines in which XAF1 was either knocked down or overexpressed were constructed. The expression levels of the apoptosis-related genes caspase 3, caspase 8, caspase 9, and poly-(ADP-ribose) polymerase (PARP) were down-regulated in the XAF1 knockdown (24-48 h postinfection) but were up-regulated in XAF1 overexpressing cells (36 h postinfection). This is the first study of the role of XAF1 in promoting apoptosis in vascular endothelial cells after DENV2 infection.
authors.affiliation: Institute of Immunology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Xigui
authors.initials: X
authors.lastname: Long
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Yiming
authors.initials: Y
authors.lastname: Qi
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.forename: Zilian
authors.initials: Z
authors.lastname: Wang
authors.forename: Ximeng
authors.initials: X
authors.lastname: Zhang
authors.forename: Duoduo
authors.initials: D
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Junqi
authors.initials: J
authors.lastname: Huang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D003715:Dengue / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D003716:Dengue Virus / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D055785:Gene Knockdown Techniques; D055106:Genome-Wide Association Study; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis / Q000235:genetics; D013997:Time Factors; D059467:Transcriptome / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; C417551:XAF1 protein, human; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases