Anti-Influenza-A Hemagglutinin H1N1 polyclonal antibody

In this study, we demonstrated an essential function of the hexosamine biosynthesis pathway (HBP)-associated O-linked beta-N-acetylglucosamine (O-GlcNAc) signaling in influenza A virus (IAV)-induced cytokine storm. O-GlcNAc transferase (OGT), a key enzyme for protein O-GlcNAcylation, mediated IAV-induced cytokine production. Upon investigating the mechanisms driving this event, we determined that IAV induced OGT to bind to interferon regulatory factor-5 (IRF5), leading to O-GlcNAcylation of IRF5 on serine-430.O-GlcNAcylation of IRF5 is required for K63-linked ubiquitination of IRF5 and subsequent cytokine production. Analysis of clinical samples revealed that IRF5 is O-GlcNAcylated, and higher levels of proinflammatory cytokines correlated with higher levels of blood glucose in IAV-infected patients. We identified a molecular mechanism by which HBP-mediated O-GlcNAcylation regulates IRF5 function during IAV infection, highlighting the importance of glucose metabolism in IAV-induced cytokine storm.

Treatments against influenza A viruses (IAV) have to be updated regularly due to antigenic drift and drug resistance. Poly (ADP-ribose) polymerases (PARPs) are considered effective therapeutic targets of acute lung inflammatory injury. This study aimed to explore the effects of PARP-1 inhibitor olaparib on IAV-induced lung injury and the underlying mechanisms. Male wild-type C57BL/6 mice were intranasally infected with IAV strain H1N1 to mimic pneumonia experimentally. Olaparib at different doses was intraperitoneally injected 2 days before and 5 consecutive days after virus stimulation. On day 6 post-infection, lung tissues as well as bronchoalveolar lavage fluid (BALF) were sampled for histological and biochemical analyses. Olaparib increased the survival rate of IAV mice dose-dependently. Olaparib remarkably reduced IAV mRNA expression, myeloperoxidase (MPO) level, and inflammatory cell infiltration in IAV lungs. Moreover, olaparib significantly reduced the level of interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, IL-6, and IL-4 and increased IL-10 in IAV lungs. Also, olaparib efficiently reduced IL-6, monocyte chemotactic protein (MCP)-1, granulocyte colony-stimulating factor (G-CSF), TNF-alpha, chemokine (C-X-C motif) ligand (CXCL)1, CXCL10, chemokine (C-C motif) ligand (CCL)3, and regulated on activation, normal T cell expressed and secreted (RANTES) release in IAV BALF. Olaparib decreased PARylated protein content and p65, I kappa B alpha phosphorylation in IAV lung tissues.This study successfully constructed the pneumonia murine model using IAV. Olaparib decreased IAV-induced mortality in mice, lung injury, and cytokine production possibly via modulation of PARP-1/NF-kappa B axis.