| Author |
Clarke, Jennifer N. Davies, Lorena K. Calvert, Julie K. Gliddon, Briony L. Al Shujari, Wisam H. Aloia, Amanda L. Helbig, Karla J. Beard, Michael R. Pitson, Stuart M. Carr, Jillian M. |
| Description |
Country affiliation: Australia Author Affiliation: Clarke JN ( 1âMicrobiology and Infectious Diseases, School of Medicine, Flinders University, Bedford Park, Adelaide, South Australia 5042, Australia.); Davies LK ( 2âCentre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia 5000, Australia.); Calvert JK ( 1âMicrobiology and Infectious Diseases, School of Medicine, Flinders University, Bedford Park, Adelaide, South Australia 5042, Australia.); Gliddon BL ( 2âCentre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia 5000, Australia.); Al Shujari WH ( 1âMicrobiology and Infectious Diseases, School of Medicine, Flinders University, Bedford Park, Adelaide, South Australia 5042, Australia.); Aloia AL ( 1âMicrobiology and Infectious Diseases, School of Medicine, Flinders University, Bedford Park, Adelaide, South Australia 5042, Australia.); Helbig KJ ( 3âSchool of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia.); Beard MR ( 3âSchool of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia.); Pitson SM ( 2âCentre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia 5000, Australia.); Carr JM ( 1âMicrobiology and Infectious Diseases, School of Medicine, Flinders University, Bedford Park, Adelaide, South Australia 5042, Australia.) |
| Abstract |
Sphingosine kinase (SK) 1 is a host kinase that enhances some viral infections. Here we investigated the ability of SK1 to modulate dengue virus (DENV) infection in vitro. Overexpression of SK1 did not alter DENV infection; however, targeting SK1 through chemical inhibition resulted in reduced DENV RNA and infectious virus release. DENV infection of SK1â»/ â» murine embryonic fibroblasts (MEFs) resulted in inhibition of infection in an immortalized line (iMEF) but enhanced infection in primary MEFs (1°MEFs). Global cellular gene expression profiles showed expected innate immune mRNA changes in DENV-infected WT but no induction of these responses in SK1â»/â» iMEFs. Reverse transciption PCR demonstrated a low-level induction of IFN-ß and poor induction of mRNA for the interferon-stimulated genes (ISGs) viperin, IFIT1 and CXCL10 in DENV-infected SK1â»/â» compared with WT iMEFs. Similarly, reduced induction of ISGs was observed in SK1â»/â» 1°MEFs, even in the face of high-level DENV replication. In both iMEFs and 1°MEFs, DENV infection induced production of IFN-ß protein. Additionally, higher basal levels of antiviral factors (IRF7, CXCL10 and OAS1) were observed in uninfected SK1â»/â» iMEFs but not 1°MEFs. This suggests that, in this single iMEF line, lack of SK1 upregulates the basal levels of factors that may protect cells against DENV infection. More importantly, regardless of the levels of DENV replication, all cells that lacked SK1 produced IFN-ß but were refractory to induction of ISGs such as viperin, IFIT1 and CXCL10. Based on these findings, we propose new roles for SK1 in affecting innate responses that regulate susceptibility to DENV infection. |
