The biology of Cryptococcus neoformans melanization

新生隐球菌是导致数千人死亡的一种重要的人类真菌病原体。 每年，主要是免疫抑制的个体。CN制造黑色素，这是一种能够执行多种 在动植物王国中发挥作用。在真菌中，黑色素增强细胞壁，抵御紫外线 辐射和有毒金属，利用高能电磁辐射，并有助于毒力。在……里面 黑化除了增加毒性外，还会降低真菌细胞对抗真菌药物的敏感性。 而且可能会增加治疗真菌感染的难度，真菌感染通常是慢性的，而且出了名的难。 根除。尽管黑色素很重要，但人们对它的结构知之甚少，因为它不溶于水， 无定形，很难分析。这项研究计划采取了多学科的方法来研究 隐球菌黑化问题，结合生化、细胞生物学和光谱学(固态 核磁共振)技术，以揭示黑化的机制及其对宿主-微生物相互作用的影响。 目前的应用旨在阐明用于将黑色素输出到皮肤外部的囊泡途径。 细胞，研究脂类在黑色素合成中的作用，研究黑色素如何影响 CN和巨噬细胞，并鉴定黑素合成的小分子抑制物。以黑色素为靶标的药物有 潜在的价值，因为它们可以应用于广泛的病原真菌。四个相关但 提出了独立的目标：目标1.建立CN细胞壁黑化的机制；目标2.至 确定脂滴中的中性脂类如何影响黑色素的合成和沉积；目的3.建立 黑化如何破坏CN-巨噬细胞相互作用的机制；以及目的4.识别CN 黑色素抑制剂，并建立其作用机制。

Cryptococcus neoformans (CN) is an important human fungal pathogen responsible for thousands of deaths each year, primarily in immunosuppressed individuals. CN makes melanin, a pigment that performs a variety of functions in the plant and animal kingdoms. In fungi, melanin reinforces cell walls, shields against ultraviolet radiation and toxic metals, harnesses high-energy electromagnetic radiation, and contributes to virulence. In addition to contributing to virulence, melanization reduces the susceptibility of fungal cells to antifungal agents and can contribute to the difficulty in treating fungal infections, which are often chronic and notoriously difficult to eradicate. Despite its importance, little is known about the structure of melanin because it is insoluble and amorphous, making it difficult to analyze. This research program takes a multidisciplinary approach to studying the problem of cryptococcal melanization, combining biochemical, cell biology, and spectroscopic (solid state NMR) techniques to uncover the mechanisms of melanization and its impact on the host-microbe interaction. The current application proposes to elucidate the vesicular pathway used to export melanin to the exterior of the cell, investigate the role of lipids in melanin synthesis, investigate how melanin affects the interactions between CN and macrophages, and identify small molecule inhibitors of melanogenesis. Agents that target melanin are potentially valuable because they could be applied against a broad array of pathogenic fungi. Four related but independent aims are proposed: Aim 1. To establish the mechanism for CN cell wall melanization; Aim 2. To determine how neutral lipids in lipid droplets influence melanin synthesis and deposition; Aim 3. To establish the mechanism for how melanization subverts the CN-macrophage interaction; and Aim 4. To identify CN melanin inhibitors and establish their mechanisms of action.