Dengue virus induces interferon-β by activating RNA sensing pathways in megakaryocytes

Abstract

Activation of innate receptors in megakaryocytes (MKs) may affect the ability to produce functional platelets. Low platelet count is one of the clinical manifestations of dengue virus (DENV) infection. In MKs, the effect of innate receptors during DENV-infection is not well studied. Here we used MEG-01 cells to investigate DENV serotype 2 induced innate receptors in these cells. DENV RNA was estimated by qRT-PCR in the culture supernatant. The expression of innate receptors was determined by western blot and qPCR. DENV infection led to increased expression of RIG-I at 24 hrs post-infection (hpi) and MDA-5 at 48 and 72 hpi (p<0.05). However, no change in the expression of TLR3 at protein level was observed. Activation of MDA-5 resulted in increased expression of IFN-β and ISG-15 in DENV infected MEG-01 cells, which was further confirmed by MDA-5 siRNA treatment. Apart from inducing innate receptors, DENV significantly decreases the expression of CD61, an activation marker of megakaryocyteson MEG-01 cells as observed by flow cytometry analysis (p<0.01). Results from this study confirm that DENV infection activates the type-I interferon in megakaryocytes and may play a significant role in maturation and development.

Keywords: Dengue virus; IFN-β; MDA-5; Megakaryocytes; RIG-I; TLR3.