Figure 8. Blocking of Notch signaling abrogates survival rate, lung pathology, and viral load.

GSI (10 nM; 50 µl volume) was intranasally administrated to mice on day 1 and day 4 after influenza virus challenge. 20% DMSO in 50 µl was used as a control for GSI. (A) Survival rate of WT mice treated with either control DMSO (black) or GSI (red) after intranasal injection with PBS only (dotted line) or H1N1 (solid line). **P<0.01 compared with H1N1 injection group treated with DMSO (B) Histological appearance of lungs isolated from WT mice treated with either control DMSO or GSI at day 7 after influenza virus infection stained with H&E. Original magnification, ×100. (C–E) Viral load in WT mice treated with DMSO or GSI at 2 and 7 days after infection of influenza virus (1×10⁴ PFU) measured by TCID₅₀ (C); Results are shown in log₁₀ scale per lobe. H1N1 viral mRNAs, M1 (D) and NS (E), were measured. Results are expressed as RNA copies normalized to GAPDH expression levels, as determined by real-time PCR. **P<0.01 compared with H1N1 injection group treated with DMSO. (F) mRNA exprerssion of Hes1 from whole lungs. (G) FACS analysis of intracellular staining of CD4⁺ cells, CD8⁺ cells, NK1.1⁺ cells for IFN-γ. (H) Cytokine level of IFN-γ from whole lungs was measured using a Luminex system. *P<0.05 compared with H1N1 injection group treated with DMSO. Data shown indicate mean ± SEM and are from a representative experiment of 2 independent experiments. Each time point represents 4–5 mice per group.