Role of indirubin-3'-oxime as an antiviral and immunomodulatory agent in the treatment of severe human influenza virus infection

Abstract

Introduction and Project Objectives Human disease caused by highly pathogenic avian influenza A (HPAI) (H5N1) is associated with fulminant viral pneumonia and mortality rates in excess of 60%. Acute respiratory syndrome (ARDS) has been found to be the most severe form of acute lung injury caused by H5N1 virus infection while cytokine dysregulation and viral replication are thought to contribute to its pathogenesis. In this study, the antiviral and anti-inflammatory effects of two indirubin derivatives: indirubin-30-oxime (IM) and E804 on primary human peripherial blood-derived macrophages and type-I like pneumocytes (human alveolar epithelial cells) during influenza A (H5N1) virus infection were investigated. Methods Primary human macrophages and type-I like pneumocytes were pre-treated with IM or E804 for 1 hour and then infected with influenza A viruses, H5N1 and H1N1. Samples of culture supernatant were collected for virus titration or cytokine analysis. Total RNA was extracted from cells for analysis of cytokine gene expression by qRT-PCR . Results We found that both of the indirubin derivatives strongly suppress the pro-inflammatory cytokines including IP-10 (CXCL10), one of the key factors which contribute to the lung inflammation during H5N1 virus infection. In addition, we also demonstrated that the indirubin derivative delays the virus replication in the primary cell culture models. Conclusion Our results showed that indirubin derivatives have a potential to be used as an adjunct to antiviral therapy for the treatment of severe human H5N1 disease.