Role of mycobacterial dynamin-like proteins in the biogenesis of membrane vesicles, and host-pathogen interactions

尽管广泛使用了减毒疫苗和几种抗生素，结核病(TB)仍然是 这是一个全球公共卫生问题。2019年有超过120万人死于结核病。这种可怕的情况使情况更加复杂 通过增加耐抗生素的结核分枝杆菌(Mtb)菌株的流行，主要 人类结核病的病原体。结核分枝杆菌成功的核心是其躲避、调节甚至操纵的能力 宿主免疫防御反应。因此，破坏免疫系统的细菌因素 是结核病干预的潜在目标。 像许多其他细菌一样，结核分枝杆菌在体外和体内都能主动产生细胞外小泡(EV)。这些是 膜封闭的球形结构，使细菌能够集中和分泌各种 分子，并与环境中的其他细胞进行交流。结核分枝杆菌感染肠道病毒释放的研究 巨噬细胞能够将致病因子和免疫调节分子运送到宿主细胞中， 以及细胞外环境。来自体外研究的有力证据表明，EVS可能允许结核分枝杆菌远程 影响旁观者的免疫细胞。然而，对所涉及的分子机制的了解有限 在囊泡的生物发生中，缺乏在囊泡生产方面存在缺陷的突变体阻碍了在 阐明囊泡分泌与结核分枝杆菌毒力的相关性。我们的初步工作鉴定出了类似动力素的 Mtb蛋白(DLP)是EVS有效释放的必需因子，并鉴定了一个DLP突变体 囊泡的生物发生。我们现在可以很好地分析DLP在囊泡形成中的作用，并评估 利用结核病的小鼠模型，研究EV在感染过程中的作用；这些是这项提案的主要目标。 我们预计，这些发现将通过突出靶向囊泡释放的方法来推进结核病领域，或扰乱 囊泡在宿主抗结核中的作用。

Despite the widespread use of an attenuated vaccine and several antibiotics, tuberculosis (TB) continues to be a global public health problem. Over 1.2 million people died from TB in 2019. This dire situation is compounded by increasing prevalence of antibiotic resistant strains of Mycobacterium tuberculosis (Mtb), the main etiological agent of human TB. Central to Mtb success is its ability to evade, modulate, and even manipulate host immune defense response. Consequently, bacterial factors involved in undermining the immune system are potentially good targets for TB intervention. Like many other bacteria, Mtb actively produces extracellular vesicles (EVs) in vitro and in vivo. These are membrane enclosed spherical structures that allow the bacteria to concentrate and secrete a variety of molecules, and communicate with other cells in their environment. The release of EVs by Mtb infecting macrophages enables the delivery of pathogenicity factors and immunomodulatory molecules into the host cell, and the extracellular milieu. Strong evidence from in vitro studies indicates that EVs may allow Mtb to remotely influence bystander immune cells. However, the limited understanding of the molecular mechanisms involved in vesicle biogenesis, and the lack of mutants deficient in vesicle production have impeded progress in elucidating the relevance of vesicle secretion to Mtb virulence. Our preliminary work identified the dynamin-like proteins (DLP) of Mtb as essential factors for efficient EVs release and characterized a DLP mutant deficient in vesicle biogenesis. We are now well positioned to dissect DLP's function in vesicle formation and assess the role of EV production during infection, using a mouse model of TB; those are the main goals of this proposal. We anticipate the findings will advance the TB field by highlighting ways to target vesicle release, or disrupt the effects of vesicles in host-resistance to TB.