Lentinus tigrinus (L. tigrinus), a white-rot fungus that grows naturally on rotten hardwood during spring and summer in China, is an edible and medicinal mushroom containing a valuable combination of nutrients including high amino acid concentrations and low sugar levels. However, no reports have isolated and characterized FIP genes from L. tigrinus to date. In our study, two novel fungal immunomodulatory proteins (FIPs) from Lentinus tigrinus were identified and named Fip-lti1 and Fip-lti2. The bioactive characteristics of Fip-lti1 and Fip-lti2 were compared to a well-known FIP (LZ-8 from Ganoderma lucidum) to investigate the effect of Fip-lti1 and Fip-lti2 expression on Concanavalin A (ConA)-induced liver injury. Both Fip-lti1 and Fip-lti2 protected livers from ConA-induced necrosis, as evidenced by decreased serum aminotransferase levels (AST, ALT) and relieved liver histology. Levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and oxidative stress (SOD, MDA) were shown to be reduced by expressing Fip-lti1 and Fip-lti2. In addition, the hepatoprotective effect of Fip-lti1, Fip-lti2, and LZ-8 correlated with ameliorating the imbalance of Th1/Th2 (IFN-γ/IL-4). The observed liver protection of Fip-lti1 and Fip-lti2 was mechanistically explored. Treatments with Fip-lti1 and Fip-lti2 regulated GATA3/T-bet expression, activated the decreased Nrf-2/HO-1 pathway, and countered the upregulated NLRP3/ASC/NF-κBp65 signaling in ConA-stimulated liver injury. In conclusion, we identified two fungal proteins (Fip-lti1 and Fip-lti2) that can protect liver from ConA-induced liver injury.

• Yingnv Gao(National Engineering Research Center of Edible Fungi; Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture; Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, Shanghai, PR China) | Yingnv Gao0
• Dapeng Bao(National Engineering Research Center of Edible Fungi; Key Laboratory of Applied Mycological Resources and Utilization, Ministry of Agriculture; Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, Shanghai, PR China)