The Translational Response of C. neoformans to Oxidative Stress and Macrophage Phagocytosis.

环境真菌新型隐球菌能够适应人类宿主，在易感个体中，可引起致命的脑膜炎，不进行抗真菌治疗是致命的。新生梭状芽孢杆菌占全世界艾滋病相关死亡的约15%，是移植人群死亡和同种异体移植物损失的重要原因。与巨噬细胞的相互作用对感染的结果很重要。在对细胞内巨噬细胞环境的反应中，新生C.表达促进生存的因子，包括防止吞噬溶酶体酸化的脲酶，以及解毒活性氧和修复氧化损伤的活性氧应激反应因子。我们提供了令人信服的初步数据，表明脲酶和ROS反应效应物都是通过激酶Gcn2在mRNA翻译水平上调节的。Gcn2是C. neoformans中唯一磷酸化真核翻译起始因子2 （eIF2）的激酶，从而调节翻译起始。在这次合作中，Panepinto实验室在C. neoformans翻译调控方面的专业知识与McManus实验室开发的创新计算和基因组学方法协同作用，研究氧化应激的翻译反应，并首次研究巨噬细胞感染期间C. neoformans的翻译调控。这项建议包括两个目标。第一个目标将使用核糖体分析和RNA-seq来研究氧化应激反应的全基因组翻译调控，并确定GCN2缺失对ROS反应基因表达和巨噬细胞氧化杀伤易感性的影响。第二个目的是研究新生C.在骨髓源性巨噬细胞细胞内生长过程中所采用的翻译调控及其对Gcn2的依赖性。这些研究将提供一个全面的视角，了解新生C.如何在氧化应激和巨噬细胞感染过程中重新编程其翻译体。由于翻译控制的基本重要性，巨噬细胞适应过程中选择的翻译过程有望包括未来治疗开发的潜在靶点。

The environmental fungus Cryptococcus neoformans is capable of adapting to the human host, and in susceptible individuals, can cause deadly meningitis that is fatal without antifungal therapy. C. neoformans is responsible for ~15% of AIDS-related deaths worldwide, and is a significant cause of mortality and allograft loss in the transplant population. Interactions with macrophages are important to the outcome of infection. In response to the macrophage intracellular environment, C. neoformans expresses factors that promote survival, including the enzyme urease that prevents acidification of the phago-lysosome, and reactive oxygen stress response factors that detoxify reactive oxygen species and repair oxidative damage. We present compelling preliminary data to suggest that both urease and ROS response effectors are regulated at the level of mRNA translation through the kinase Gcn2. Gcn2 is the sole kinase in C. neoformans that phosphorylates eukaryotic translation initiation factor 2 (eIF2), thereby regulating translation initiation. In this collaboration, the expertise of the Panepinto lab in translational regulation in C. neoformans synergizes with the innovative computational and genomics approaches developed by the McManus lab to investigate the translational response to oxidative stress and perform the first study of translational regulation in C. neoformans during macrophage infection. The proposal consists of two aims. The first aim will use ribosome profiling and RNA-seq to investigate the genome wide translational regulation in response to oxidative stress and determine the consequences of GCN2 deletion on ROS response gene expression and susceptibility to oxidative killing by macrophages. The second Aim will examine the translational regulation employed by C. neoformans during intracellular growth in bone marrow derived macrophages, and its dependence on Gcn2. These studies will provide a comprehensive view of how C. neoformans reprograms its translatome in response to oxidative stress, and during macrophage infection. Due to the fundamental importance of translational control, the processes selected for translation during macrophage adaptation are expected to include potential targets for future therapeutic development.