title: Mosquito cellular factors and functions in mediating the infectious entry of chikungunya virus.
abstract: Chikungunya virus (CHIKV) is an arthropod-borne virus responsible for recent epidemics in the Asia Pacific regions. A customized gene expression microarray of 18,760 transcripts known to target Aedes mosquito genome was used to identify host genes that are differentially regulated during the infectious entry process of CHIKV infection on C6/36 mosquito cells. Several genes such as epsin I (EPN1), epidermal growth factor receptor pathway substrate 15 (EPS15) and Huntingtin interacting protein I (HIP1) were identified to be differentially expressed during CHIKV infection and known to be involved in clathrin-mediated endocytosis (CME). Transmission electron microscopy analyses further revealed the presence of CHIKV particles within invaginations of the plasma membrane, resembling clathrin-coated pits. Characterization of vesicles involved in the endocytic trafficking processes of CHIKV revealed the translocation of the virus particles to the early endosomes and subsequently to the late endosomes and lysosomes. Treatment with receptor-mediated endocytosis inhibitor, monodansylcadaverine and clathrin-associated drug inhibitors, chlorpromazine and dynasore inhibited CHIKV entry, whereas no inhibition was observed with caveolin-related drug inhibitors. Inhibition of CHIKV entry upon treatment with low-endosomal pH inhibitors indicated that low pH is essential for viral entry processes. CHIKV entry by clathrin-mediated endocytosis was validated via overexpression of a dominant-negative mutant of Eps15, in which infectious entry was reduced, while siRNA-based knockdown of genes associated with CME, low endosomal pH and RAB trafficking proteins exhibited significant levels of CHIKV inhibition. This study revealed, for the first time, that the infectious entry of CHIKV into mosquito cells is mediated by the clathrin-dependent endocytic pathway.
authors: Laboratory of Molecular RNA Virology and Antiviral Strategies, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore, Singapore.
authors: Regina Ching Hua
authors: RC
authors: Lee
authors: Hapuarachchige Chanditha
authors: HC
authors: Hapuarachchi
authors: Karen Caiyun
authors: KC
authors: Chen
authors: Khairunnisa' Mohamed
authors: KM
authors: Hussain
authors: Huixin
authors: H
authors: Chen
authors: Swee Ling
authors: SL
authors: Low
authors: Lee Ching
authors: LC
authors: Ng
authors: Raymond
authors: R
authors: Lin
authors: Mary Mah-Lee
authors: MM
authors: Ng
authors: Justin Jang Hann
authors: JJ
authors: Chu
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D002460:Cell Line; D002646:Chikungunya virus / Q000502:physiology*; D020869:Gene Expression Profiling; D054884:Host-Pathogen Interactions; D046228:Microarray Analysis; D046529:Microscopy, Electron, Transmission; D053586:Virus Internalization