The Role of Glutamine Metabolism for P. gingivalis-Induced Non-Canonical Autophagy in Epithelial Cells

越来越多的证据表明谷氨酰胺(Gln)代谢可以影响关键的代谢和自噬 细胞事件。牙龈卟啉单胞菌(P.G)是一种主要的牙周病、挑剔、致病和致病的细菌。 成功的牙龈粘膜定殖者，最近被发现可以诱导一种特殊形式的牙周炎 人牙龈上皮细胞(GECs)的自噬虽然GEC的功能是本质上重要的第一条线 对于牙龈的免疫防御，P.G可以利用GECs来获得成功的持久性利基 口腔粘膜和潜在的全身传播途径。尽管越来越多的证据表明 谷氨酰胺代谢改变可导致细胞病理，但关于宿主谷氨酸氨基转移酶如何发挥作用仍存在知识空白 新陈代谢可能受到细菌的影响，以调节宿主的氧化还原动态平衡，并潜在地促进 细菌在血管内皮细胞中存活。最近，我们发现P.G稳步增加健壮的谷胱甘肽(GSH)。 在GEC中产生以对抗宿主介导的氧化应激驱动的病原体清除。我们的新发现， 首次表明，P.G感染改变了宿主GECs中GSH合成的GLN代谢。 此外，我们最近证明了P.G在GEC中诱导了一种亲细菌形式的自噬，其中 富含内质网/微管相关蛋白1A/1B-轻链3(LC3)双膜 自噬小体作为P.G的复制小生境，保护细菌免受抗菌素降解 小路。我们的新数据表明，这些含P.G的细菌的生物发生和维持 自噬小体依赖于关键的氧化还原分子谷胱甘肽过氧化物酶1(GPX1)。这个 通过增加GEC细胞环境中的游离Gln水平，可以显著改变对GPX1的依赖。 因此，我们对这一提议的主要假设是P.G改变了GEC中宿主Gln的代谢，以 维持宿主氧化还原动态平衡，并特别有助于GPX1驱动的亲细菌的生物发生 自噬的形式。为了检验这一假说，本文提出了两个具体目标。目标1将描述 P.G感染期间发生的与宿主细胞Gln特异相关的表型分子事件 代谢和宿主细胞的氧化还原状态，允许P.G在GEC中的细胞内存活。目标2将 从机制上确定参与P.G诱导的自噬的分子相互作用组 GECs中宿主谷氨酰胺代谢的调控。这些将共同确定谷氨酰胺代谢的哪些元素 这些途径对于P.G在GEC中的自噬生存至关重要，并将阐明特定的分子。 在P.G感染时，宿主谷氨酸氨基代谢的变化所驱动的促细菌自噬的机制。 总体而言，这项建议将有助于确定新的靶向治疗策略，以控制 P.G在口腔粘膜及其他部位的慢性细胞内定植。为此获得F31奖学金 该提案将促进申请者的研究目标，关键是有助于她在口语领域的培训 生物学，并将促进她作为口腔健康学术科学家的独特发展。

Growing evidence underlines that Glutamine (Gln) metabolism can influence key metabolic and autophagic cellular events. Porphyromonas gingivalis (P.g) is a major periodontopathic, fastidious, pathobiont and successful colonizer of gingival mucosa, which has recently been identified to induce a special form of autophagy in human gingival epithelial cells (GECs). While GECs function as an intrinsically important first line of immune defense of the gingiva, GECs can be exploited by P.g for securing a successful persistence niche in the oral mucosa and a potential systemic dissemination route. Despite the growing evidence pinpointing that altered Gln metabolism can contribute to cellular pathologies, knowledge gaps remain regarding how host Gln metabolism could be influenced by bacteria to regulate host redox homeostasis and potentially promote bacterial survival in the GECs. Recently, we discovered that P.g steadily increases robust Glutathione (GSH) production in GECs to combat host-mediated oxidative stress-driven pathogen clearance. Our novel findings, for the first time, show that P.g infection alters host Gln metabolism, a component of GSH synthesis, in GECs. In addition, we recently demonstrated that P.g induces a pro-bacterial form of autophagy in GECs, where Endoplasmic Reticulum-rich (ER)/Microtubule-associated protein 1A/1B-light chain 3 (LC3) double membrane autophagosomes act as replicative niches for P.g and protect the bacteria from antimicrobial degradation pathways. Our novel data shows that the biogenesis and maintenance of these P.g-containing autophagosomes is dependent on the critical redox molecule, Glutathione Peroxidase 1 (GpX1). The dependency on GpX1 can be markedly altered by increasing free Gln levels in GECs' cellular environment. Thus, our overarching hypothesis for this proposal is that P.g alters host Gln metabolism in GECs to maintain host redox homeostasis and specifically contributes to the biogenesis of a GpX1-driven, pro-bacterial form of autophagy. Two Specific Aims are proposed to test this hypothesis. Aim 1 will characterize the phenotypic molecular events occurring during P.g infection that specifically associate with host cell Gln metabolism and the host cell redox state, allowing for the intracellular survival of P.g in GECs. Aim 2 will mechanistically determine the molecular interactome involved in P.g-induced autophagy through the modulation of host Gln metabolism in GECs. These collectively will identify what elements of the Gln metabolic pathways are critical for the autophagic survival of P.g in GECs, and will elucidate the specific molecular machineries involved in pro-bacterial autophagy driven by changes in host Gln metabolism upon P.g infection. Overall, this proposal will contribute to the identification of novel targeted therapeutic strategies to control the chronic intracellular colonization of P.g in the oral mucosa and beyond. Receiving the F31 Fellowship for this proposal will further the applicant's research goals, critically contribute to her training in the field of Oral Biology, and will foster her unique development as an oral health academic scientist.