Interaction between proteins of the PPARγ and NFκB immune response pathways and rotavirus non-structural proteins.

Cells infected with MA104 rotavirus and/or transfected with plasmids expressing NSP proteins, were analyzed for expression of cellular proteins related to NFκB and PPARγ pathways and evaluated through the ELISA, luminescence, flow cytometry and Western blot techniques. The association between cellular and viral (NSPs) proteins was examined by ELISA, epifluorescence and confocal microscopy techniques. It was observed that NSP1 protein interacts with RXR, NSP1, and NSP3 with PPARγ, NSP2 with p-IKKα/ß and NSP5 with NFκB proteins. We have found that phosphorylated PPARγ is localized in cytoplasm and transcriptional activity of PPRE is diminished. These results lead to the conclusion, that RRV activates the proinflammatory pathway, increasing the expression of NFκB and possibly by PPARγ phosphorylation, its translocation to the nucleus is impeded, thus inactivating the proinflammatory pathway. Keywords: rotavirus; PPARγ; NFκB; NSPs; RRV.

PPARγ Agonists as an Anti-Inflammatory Treatment Inhibiting Rotavirus Infection of Small Intestinal Villi.

Rotavirus infection has been reported to induce an inflammatory response in the host cell accompanied by the increased expression or activation of some cellular molecules including ROS, NF-κB, and COX-2. PPARγ stimulation and N-acetylcysteine (NAC) treatment have been found to interfere with viral infections including rotavirus infection. Small intestinal villi isolated from in vivo infected mice with rotavirus ECwt were analyzed for the percentage of ECwt-infected cells, the presence of rotavirus antigens, and infectious virion yield following treatment with pioglitazone. Isolated villi were also infected in vitro and treated with PPARγ agonists (PGZ, TZD, RGZ, DHA, and ALA), all-trans retinoic acid (ATRA), and NAC. After treatments, the expression of cellular proteins including PPARγ, NF-κB, PDI, Hsc70, and COX-2 was analyzed using immunochemistry, ELISA, immunofluorescence, and Western blotting. The results showed that rotavirus infection led to an increased accumulation of the cellular proteins studied and ROS. The virus infection-induced accumulation of the cellular proteins studied and ROS was reduced upon pioglitazone treatment, causing also a concomitant reduction of the infectious virion yield. We hypothesized that rotavirus infection is benefiting from the induction of a host cell proinflammatory response and that the interference of the inflammatory pathways involved leads to decreased infection.