NAMO Inhibits HSV-1-induced Microglial Inflammatory Response Through Sirt1-NF-κB Pathway

Objective: To explore the activity and anti-inflammatory mechanism of Nicotinamide N-oxide(NAMO)in inhibiting HSV-1-induced inflammatory response in vitro and in vivo,and provide a basis and foundation for the development of new HSE therapeutic drugs.Methods: First,the drug toxicity of NAMO on microglia was detected by MTT assay,and the effect of NAMO on the expression of inflammatory factors was verified by q RT-PCR and ELISA experiments;then the morphology of NAMO activation on microglia was verified by immunofluorescence and flow cytometry experiments.The effects of changes and polarization types were verified by q RT-PCR,enzyme activity detection kit and Western Blot experiments to verify the effect of NAMO on SIRT1 protein and the activation of its downstream NF-κB signaling pathway;The HSE mouse model was established by intranasal instillation of HSV-1to evaluate the anti-inflammatory activity of NAMO in vivo.Results: MTT experimental data showed that NAMO was less toxic to human and murine microglia,and the IC50 values were all greater than 320 μM;the results of q RT-PCR and ELISA showed that 40,80,and 160 μM NAMO could significantly inhibit the dose-dependently.Gene and protein expression levels of inflammatory factors IL-6,IL-1β and TNF-α in microglial cells induced by HSV-1;immunofluorescence and flow cytometry experiments showed that NAMO can inhibit the morphology of microglia induced by HSV-1 Changes and influences the transition of microglial polarization type from M1 type to M2 type;further mechanism studies found that NAMO can inhibit HSV-1-induced microglial inflammatory response through the SIRT1-NF-κB pathway,and NAMO is also very important.It may be combined with SIRT1 to activate SIRT1;the final in vivo experimental results also showed that NAMO can improve the symptoms of herpes simplex virus encephalitis in HSE mice,and can also improve brain inflammation in HSE mice through the SIRT1-NF-κB signaling pathway.Conclusions: NAMO has anti-inflammatory activity to inhibit HSV-1-induced inflammatory response in vitro and in vivo.Mechanistic studies have shown that NAMO can exert anti-inflammatory activity by regulating SIRT1-NF-κB signaling pathway.