Monophora着色霉黑素通过抑制穿孔素释放抵抗NK细胞杀伤的作用机制研究

Fonsecaea monophora是中国南方着色芽生菌病的主要致病菌。我们前期证实黑素是其重要毒力因子，保护菌体抵御宿主杀伤，但具体机制不明。NK细胞释放穿孔素杀伤真菌是宿主重要抗真菌感染方式，我们预实验发现F. monophora色素株较白化株更能抵抗NK细胞杀伤，纯化F. monophora黑素明显减弱NK细胞对菌体的杀伤，并以剂量依赖方式减少NK细胞穿孔素释放。据此我们设想：F. monophora黑素可能通过抑制穿孔素释放抵抗NK细胞杀伤。本项目拟通过构建色素株、白化株和加入黑素颗粒的白化株的NK细胞共培养模型、小鼠感染模型，在体内外阻断NK细胞穿孔素释放，明确F. monophora黑素通过抑制穿孔素释放抵抗NK细胞杀伤的作用；通过建立与不同菌株共培养后的NK细胞的基因表达谱，分析并验证黑素抑制NK细胞穿孔素释放的分子机制，为开发新型药物提供科学依据。

Fonsecaea monophora is the main etiological agent of chromoblastomycosis in southern China. Melanin is an important virulence factor of F. monophora, which protects F. monophora against host damage, while the detailed mechanism is still unknown. Perforin release from NK cells is an important strategy used by host to kill fungi. Our preliminary study demonstrated that F. monophora with melanin was more resistant to the damage of NK cells than F. monophora without melanin. Most interestingly, the purified melanin from F. monophora significantly attenuated the damage of NK cells to F. monophora and reduced the release of perforin from NK cells in a dose-dependent manner. Therefore, we propose a new mechanism of F. monophora resisting to host damage (scientific hypothesis): F. monophora may resist NK cell damage by inhibiting the release of perforin from NK cells through melanin. In this study, F. monophora strains with or without melanin and F. monophora albino strain with melanin particles will be used to infect NK cells in vitro and mice in vivo, the protective effect of F. monophora melanin through inhibiting the release of perforin can be proved by blocking perforin release from NK cells. Then, the gene expression profiles of NK cells co-cultured with different F. monophora strains will be established, and the molecular mechanism of F. monophora melanin inhibiting the release of perforin from NK cells will be analyzed and verified. This study will provide scientific basis for exploring new drugs to treat chromoblastomycosis.