Regulation of hepatic NKT cells by CDld+ liver cells

描述（由申请人提供）：全球近2亿人患有丙型肝炎病毒（HCV），其中绝大多数患有慢性肝炎，美国近2%的人感染HCV，这是一项重大的公共卫生挑战，每年约有9，000例美国人死亡。目前。慢性肝炎经常导致肝硬化，这反过来又是肝细胞癌（HCC）的主要危险因素。虽然特异性免疫在急性和慢性丙型肝炎（CHC）中的作用正在出现，但对关键的肝脏免疫亚群随进展的变化知之甚少。适应性HCV特异性T细胞集中在肝脏中，具有天然样自然杀伤细胞（NK）和NKT，其占正常和患病肝脏白细胞的约50%。肝脏NKT参与抗急性病毒感染的保护作用，但可能被HCV破坏。对肝NKT细胞活化的调节知之甚少。本研究旨在确定丙型肝炎患者中CD 1d+肝细胞调控人类肝脏NKT主要异质群体的机制。基于我们的研究结果，我们假设在慢性丙型肝炎中，这种大量的异质性肝脏NKT群体不是保护性的，而是促进炎症和纤维化，这被认为是HCC发展的先决条件。我们建议，肝CD 1d可以提出新的脂质配体肝NKT细胞。我们有肝NKT配体的证据，我们已经从CD 1d+细胞中分离出选择性刺激iNKT的组分。这些数据提供了我们可以获得具有NKT配体样活性的级分的原理证明。该提案将利用我们在人类肝脏和对照NKT、生理性CD 1d+呈递肝细胞以及我们和合作者开发的试剂方面的独特专业知识，以从脂质库中鉴定肝脏NKT活化组分和潜在配体，为CHC和HCC中潜在的新型治疗干预措施的临床前开发提供靶标。考虑到我们已经发现的慢性NKT刺激的有害作用，这将使我们能够通过新的分子潜在地操纵肝脏NKT朝向新的治疗方法，以帮助延缓丙型肝炎向肝硬化和HCC的进展。目标1.建立人肝CD 1d反应性NKT细胞的代表性样本组，并检测候选小分子对肝NKT细胞与血液不变NKT细胞的特异性激活或抑制。1a.制备和功能表征富集的肝脏NKT面板，与我们的iNKT一起使用。1b.确定来自选择性文库的哪些iNKT配体也激活肝NKT，哪些抑制肝NKT。目标二。确定人肝NKT对肝与其他CD 1d+靶细胞的特异性，并确定特异性激活或抑制肝NKT的肝CD 1d+细胞组分。2a.确定富集的肝脏NKT细胞相对于iNKT细胞是否对肝脏与其他CD 1d+靶细胞具有明显的精细特异性。2b.鉴定特异性激活肝NKT和/或iNKT的洗脱肝CD 1d配体组分。 公共卫生相关性：全世界近2亿人患有丙型肝炎，其中许多人将发展为感染并发症，包括肝硬化和肝细胞癌。该提案旨在研究和操纵人类肝脏中的主要免疫群体“NKT”细胞，该细胞在急性感染中具有保护作用，但似乎有助于导致肝脏疾病进展的炎症和纤维化损伤。

DESCRIPTION (provided by applicant): Worldwide, nearly 200 million people have hepatitis C virus (HCV), the great majority of which have chronic hepatitis, nearly 2% in the U.S. are infected with HCV, a major public health challenge with ~9,000 U.S. deaths / yr. currently. Chronic hepatitis frequently leads to cirrhosis, which in turn is the major risk factor for hepatocellular carcinoma (HCC). Although roles of specific immunity in acute and chronic hepatitis C (CHC) are emerging, little is known about key liver immune subset changes with progression. Adaptive HCV-specific T cells are concentrated in liver with innate-like natural killer (NK) and NKT, which represent to ~50% of normal and diseased liver leukocytes. Hepatic NKT are implicated in protection against acute viral infection, but maybe subverted by HCV. Regulation of activation of hepatic NKT cells is poorly understood. This proposal is to determine mechanisms by which the major and heterogeneous population of human hepatic NKT, that we first functionally defined, are regulated by CD1d+ liver cells in hepatitis C. Based on our findings, we hypothesize that in chronic hepatitis C, this large heterogeneous population of liver NKT, instead of being protective, promote inflammation and fibrosis, believed to be prerequisites for development of HCC. We propose that hepatic CD1d can present novel lipid ligands to liver NKT cells. We have evidence for ligand(s) for hepatic NKT and we have isolated fractions from CD1d+ cells that stimulate iNKT selectively. These data provide proof-of-principle that we can obtain fractions with ligand-like activity for NKT. This proposal will exploit our unique expertise with human hepatic and control NKT, physiological CD1d+ presenting liver cells, and reagents we and collaborators have developed to identify hepatic NKT- activating fractions and potential ligands from lipid libraries, to provide target(s) for preclinical development of potential novel therapeutic interventions in CHC and HCC. Given deleterious effects of chronic NKT stimulation we have uncovered, this will enable us to potentially manipulate hepatic NKT through novel molecule(s) toward novel therapeutics to help delay progression to cirrhosis and HCC in hepatitis C. Aim 1. Establish a representative panel of human hepatic CD1d-reactive NKT cells and test candidate small molecules for specific activation or inhibition of hepatic NKT cells vs. blood invariant NKT cells. 1a. Prepare and functionally characterize enriched hepatic NKT panels for use alongside our iNKT. 1b. Determine which iNKT ligands from a selective library also activate hepatic NKT and which inhibit. Aim 2. Determine specificity of human hepatic NKT for hepatic vs. other CD1d+ target cells, and define hepatic CD1d+ cell fractions that specifically activate or inhibit hepatic NKT. 2a. Determine whether enriched hepatic NKT cells have distinct fine specificity for hepatic vs. other CD1d+ target cells relative to iNKT cells. 2b. Identify fractions of eluted liver CD1d ligands that specifically activate hepatic NKT and/or iNKT. PUBLIC HEALTH RELEVANCE: Worldwide nearly 200 million people have hepatitis C and many of these will progress to develop complications of the infection, including cirrhosis and hepatocellular carcinoma. This proposal is to study and manipulate a major immune population in the human liver, 'NKT' cells, which while protective in acute infections appear to contribute to inflammatory and fibrotic damage leading to liver disease progression.