P. gingivalis mediated disruption of autophagy in endothelial dysfunction

描述（由申请人提供）：牙龈卟啉单胞菌（Pg）不仅是牙周炎的病原体，也是多种口腔外感染的病原体，并与动脉粥样硬化（ACD）的发生和/或进展有关。心血管内皮细胞是 对于心血管疾病（CVD）（例如ACD）的发生和进展至关重要。Pg可以侵入各种类型的内皮细胞并引起这些细胞的功能障碍，导致内皮细胞的反应，其类似于已知在人ACD中发生的反应，特别是通过先天免疫途径刺激多种效应物。毫无疑问，炎症和自噬都有助于ACD。已经充分研究了ACD中经典炎症通路的PG刺激。然而，Pg介导的内皮细胞自噬的破坏对内皮功能障碍/ACD的贡献和机制尚未阐明。我们小组最近的工作表明，Pg对自噬途径的高劫持是促进内皮功能障碍的重要机制，其导致促炎反应、氧化应激增加和/或程序性细胞死亡。这导致宿主细胞无法充分响应压力，导致细胞死亡。我们推测，Pg操纵内皮细胞自噬的机制破坏了内皮细胞在氧化或高脂血症应激期间利用自噬作为恢复体内平衡的手段的能力，导致内皮功能障碍，并最终导致ACD。本申请的目的是采用体外和体内方法来研究这一假设。我们建议比较Pg菌株能够篡夺自噬和不能对内皮细胞功能障碍和ACD程度的同基因突变体的影响，无论这种机制是否独立于先天免疫信号传导引发的促炎反应发生，并确定是否打开或关闭自噬的药物将宿主细胞从Pg诱导的功能障碍中拯救出来。鉴于ACD和牙周炎中内皮功能障碍的相似性，我们预计这些研究的许多结果也与内皮细胞和口腔疾病有关。

DESCRIPTION (provided by applicant): P. gingivalis (Pg) is not only a pathogen in periodontitis but is also an etiological agent of a variety of extraoral infections and is implicatd in the initiation and/or progression of atherosclerosis (ACD). Cardiovascular endothelial cells are key to the initiation and progression of cardiovascular diseases (CVDs) such as ACD. Pg can invade various types of endothelial cells and causes dysfunction of these cells, resulting in a response by the endothelial cells that is similar to that known to occur in human ACD, especially the stimulation of multiple effectors via the innate immune pathways. There is no question that both inflammation and autophagy contribute to ACD. Pg stimulation of the classic inflammatory pathways in ACD has been well investigated. However the contribution and mechanism of Pg mediated disruption of endothelial autophagy on endothelial dysfunction/ACD has not been elucidated. Recent work by our group suggests that high jacking of the autophagic pathway by Pg is an important mechanism that promotes endothelial dysfunction which results in pro-inflammatory responses, increased oxidative stress, and/or programmed cell death. This results in an inability of the host cells to adequately respond to stress, causing cell death. We hypothesize that the mechanism by which Pg manipulates endothelial autophagy disrupts the endothelial cell's ability to use autophagy as a means of restoring homeostasis during oxidative or hyperlipidemic stress, resulting in endothelial dysfunction and, ultimately, ACD. The objective of this application is to employ both in vitro and in vivo approaches to investigate this hypothesis. We propose to compare the effects of a Pg strain able to usurp autophagy and an isogenic mutant that cannot on endothelial cell dysfunction and extent of ACD, whether or not this mechanism occurs independently of proinflammatory responses triggered by innate immune signaling, and determine if drugs that turn on or off autophagy rescue the host cell from Pg induced dysfunction. Given the similarities of endothelial dysfunction in ACD and periodontitis, we expect that many of the results of these studies would also relate to endothelial cells and oral disease.