Objective To study the inhibitory effect and its potential molecular mechanism of coptisine hydrochloride on influenza A virus (IAV). Methods CCK-8 method was used to detect the effect of coptisine hydrochloride on viability of Madin-Darby canine kidney (MDCK) and human embryonic kidney 293T cells (293T). By using an in vitro viral infection model, the regulatory effect of coptisine hydrochloride on IAV replication and viral nucleoprotein (NP) expression was detected, and its half effective concentration (EC₅₀) and half cytotoxic concentration (CC₅₀) were calculated. A mouse model infected with H1N1-UI182 was constructed, coptisine hydrochloride was given for intervention, changes in survival rate, body weight, lung index, lung tissue virus titer and viral load were detected. Hematoxylin-eosin (HE) staining was used to observe the pathological damage of lung tissue. Immunohistochemistry was used to detect the expression of NP protein in lung tissue. Western blotting and qRT-PCR were used to detect the regulatory effect of coptisine hydrochloride on transient receptor potential vanilloid 4 (TRPV4)/nuclear factor-κB (NF-κB) signaling pathway, as well as its effect on the expressions of cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β and interferon-γ (IFN-γ). Results At the cellular level, compared with model group, coptisine hydrochloride significantly inhibited IAV replication and reduced NP protein expression level (P < 0.05, 0.001). Coptisine hydrochloride had an EC₅₀ of 15.93 μg/mL and a CC₅₀ of 83.42 μg/mL in MDCK cells, and an EC₅₀ of 18.44 μg/mL and a CC₅₀ of 69.90 μg/mL in 293T cells. In the H1N1-UI182 infected mouse model, compared with model group, coptisine hydrochloride significantly improved the decline in body weight of mice, increased survival rate, and significantly reduced lung index, lung tissue virus titer and viral load (P < 0.05, 0.01, 0.001). The histopathological results showed that coptisine hydrochloride significantly reduced the inflammatory infiltration and alveolar structural damage caused by viral infection in lungs. The immunohistochemical results showed that coptisine hydrochloride significantly reduced the expression of NP protein in lung tissue. Western blotting and qRT-PCR results showed that compared with model group, coptisine hydrochloride could regulate TRPV4/NF-κB signaling pathway, significantly inhibit TRPV4 overactivation (P < 0.001), block NF-κB nuclear translocation (P < 0.001), and subsequently downregulate the expressions of pro-inflammatory factors such as TNF-α, IL-6, IL-1β (P < 0.05, 0.01, 0.001). Conclusion Coptisine hydrochloride could directly inhibit IAV replication and regulate TRPV4/NF-κB signaling pathway to improve virus induced inflammatory response, exerting anti-IAV effects.

coptisine hydrochloride  /  influenza A virus  /  TRPV4  /  NF-κB  /  inflammatory response