National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
National Animal Tuberculosis Para-Reference Laboratory (Wuhan) of Ministry of Agriculture and Rural Affairs, International Research Center for Animal Disease, Ministry of Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Cells. 2024 Jun 11;13(12):1019. doi: 10.3390/cells13121019.
causes 6.4 million cases of tuberculosis and claims 1.6 million lives annually. Mycobacterial adhesion, invasion of host cells, and subsequent intracellular survival are crucial for the infection and dissemination process, yet the cellular mechanisms underlying these phenomena remain poorly understood. This study created a (BCG) transposon library using a MycomarT7 phage carrying a Himar1 Mariner transposon to identify genes related to mycobacteria adhesion and invasion. Using adhesion and invasion model screening, we found that the mutant strain B2909 lacked adhesion and invasion abilities because of an inactive gene, which encodes a fatty-acyl CoA ligase, although the specific function of this gene remains unclear. To investigate the role of FadD18, we constructed a complementary strain and observed that expression enhanced the colony size and promoted the formation of a stronger cord-like structure; FadD18 expression also inhibited BCG growth and reduced BCG intracellular survival in macrophages. Furthermore, FadD18 expression elevated levels of the proinflammatory cytokines IL-6, IL-1β, and TNF-α in infected macrophages by stimulating the NF-κB and MAPK signaling pathways. Overall, the FadD18 plays a key role in the adhesion and invasion abilities of mycobacteria while modulating the intracellular survival of BCG by influencing the production of proinflammatory cytokines.
导致每年 640 万例结核病病例，并夺走 160 万人的生命。分枝杆菌的黏附、宿主细胞的入侵以及随后的细胞内生存对于感染和传播过程至关重要，但这些现象背后的细胞机制仍知之甚少。本研究使用携带 Himar1 Mariner 转座子的 MycomarT7 噬菌体创建了一个卡介苗（BCG）转座子文库，以鉴定与分枝杆菌黏附和入侵相关的基因。通过黏附和入侵模型筛选，我们发现突变株 B2909 由于一个失活的 基因而缺乏黏附和入侵能力，该基因编码脂肪酸酰基辅酶 A 连接酶，尽管该基因的具体功能尚不清楚。为了研究 FadD18 的作用，我们构建了一个互补菌株，并观察到 表达增强了菌落大小，并促进了更强的线状结构的形成；FadD18 表达还抑制了 BCG 在巨噬细胞中的生长和减少了 BCG 细胞内的存活。此外，FadD18 表达通过刺激 NF-κB 和 MAPK 信号通路，提高了感染巨噬细胞中促炎细胞因子 IL-6、IL-1β 和 TNF-α 的水平。总的来说，FadD18 在分枝杆菌的黏附和入侵能力中发挥关键作用，同时通过影响促炎细胞因子的产生来调节 BCG 的细胞内存活。
