title: dsRNA formed as an intermediate during Coxsackievirus infection does not induce NO production in a beta-cell line with or without addition of IFN-gamma.
abstract: Virus infection is one environmental factor that has been implicated as a precipitating event initiating beta-cell damage during the development of type 1 diabetes. One aim of this study was to investigate how permissive an insulin-producing beta-cell line, RINm5F, is to enterovirus (EV) infections. A second aim was to study if the viral replicative intermediate, double-stranded RNA (dsRNA), together with IFN-gamma results in nitric oxide (NO) production. Monolayer cultures of RINm5F cells were not permissive to infection with seven different strains of EV. However, when the growth pattern of the beta-cell line changed and the cells started to grow as free-floating RIN cell clusters (RCC), all EV strains replicated. Immunostaining for the Coxsackie-adenovirus-receptor (CAR) detected the protein on the free-floating RIN cell clusters, but not on the RINm5F cells cultured as a monolayer of beta-cells. This shows that the CAR expression can change and/or the CAR protein can be redistributed on the cell surface as a consequence of altered growth pattern thus allowing viral replication in a previously non-permissive beta-cell line. As expected, NO production was significantly increased (p<0.05) by addition of synthetic dsRNA and IFN-gamma to the RCC. In contrast, the dsRNA formed during virus infection with a Coxsackievirus B4 strain (E2) with or without addition of IFN-gamma did not induce NO production in these cells. This indicates that synthetic dsRNA does not mimic a real viral infection in that respect, and suggests an NO-independent mechanism for virus-induced beta-cell damage.
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. Anna-Karin.Berg@kbh.uu.se
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Berg
authors.forename: Asma
authors.initials: A
authors.lastname: Elshebani
authors.forename: Arne
authors.initials: A
authors.lastname: Andersson
authors.forename: Gun
authors.initials: G
authors.lastname: Frisk
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004770:Enterovirus / Q000235:genetics* / Q000502:physiology; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000378:metabolism / Q000821:virology*; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism*; D051381:Rats; D013997:Time Factors; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D012330:RNA, Double-Stranded; D009569:Nitric Oxide; D007371:Interferon-gamma