The role of regulatory T cells in biliary atresia

调节性T细胞在胆道闭锁中的作用

基本信息

批准号：
8893971
负责人：
Alexander Miethke
金额：
$ 33.38万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-15 至 2016-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8893971
关键词：
Adoptive Transfer Age Attenuated Biliary Biliary Atresia Bilirubin Binding Biological Assay CD4 Positive T Lymphocytes CD8-Positive T-Lymphocytes CD8B1 gene CXCL10 gene CXCR3 gene Cell Differentiation process Cell Transplantation Cells Child Childhood Cholestasis Chronic Coculture Techniques Cytokine Suppression Data Defect Dendritic Cells Development Disease Down-Regulation Ductal Experimental Models Extrahepatic Frequencies Future Goals Grant Hepatic Hepatocyte Human IL2RA gene Immune Immune response Immune system Immunotherapy In Vitro Infant Inflammation Inflammatory Injury Interleukin-10 Knock-out Knowledge Left Life Link Liver Liver diseases Lymphocyte Lymphocyte Activation Macaca mulatta Measures Mediating Mediator of activation protein Membrane Molecular Mus Myelogenous NK Cell Activation Names Natural Killer Cells Neonatal Obstruction Outcome Pathogenesis Pathway interactions Phase Phenotype Positioning Attribute Predisposition Process Production Publishing Regulation Regulatory Pathway Regulatory T-Lymphocyte Reporter Reporting Research Role Rotavirus Rotavirus Infections Sampling Serum Severity of illness Site Staging T-Cell Activation T-Lymphocyte Testing Time Tissues Transgenic Mice Transplantation Up-Regulation Viral Virus Virus Diseases adaptive immunity base bile duct biliary tract chemokine receptor cohort cytokine cytotoxic immune activation improved in vitro Assay in vivo in vivo Model injured innovation latency-associated protein liver injury liver transplantation migration mouse model neonate neutralizing antibody novel research study response trafficking translational study trend unpublished works validation studies

项目摘要

DESCRIPTION (provided by applicant): Biliary atresia (BA) is a progressive fibroinflammatory obstruction of the extrahepatic biliary tree and the most common indication for pediatric liver transplantation worldwide. It is uniquely restricted to the early neonatal period, and rotavirus (RRV) infection only causes BA in mice when injected during the first 3 days of life. We have reported that regulatory T cells (Tregs) are absent in the liver during this time period, but emerge rapidly following RRV challenge in older mice protected from RRV induced BA. In preliminary studies, we have shown that adoptive transfer of Treg-containing CD4+ cells prior to RRV inoculation constrained hepatic expansion of NK and CD8 lymphocytes and attenuated the BA phenotype, as evidenced by lower serum bilirubin levels and reduced inflammatory bile duct obstruction. Mechanistically, these changes were linked to down-regulation of B7 costimulatory molecules on hepatic myeloid dendritic cells. Adoptive transfer experiments with CD4 cells lacking the chemokine receptor CXCR3 indicated a critical role for local positioning of Tregs in control of hepatic immune responses. In samples of infants with BA, we found trends towards increased production of pro-inflammatory cytokines in circulating T-lymphocytes, up-regulation of B7 molecules on hepatic myeloid dendritic cells, and increased frequency of circulating Tregs lacking expression of CXCR3 compared with age- matched controls without liver injury. Based on these data we propose the overarching hypothesis that Tregs protect from neonatal bile duct injury through local control of effector lymphocyte activation. This hypothesis will be tested in three overlapping specific aims: 1) to determine the mechanisms by which Tregs constrain bile duct injury, 2) to identify pathways of immune regulation by Tregs in BA, and 3) to elucidate molecular determinants for Treg trafficking to the site of inflammation in BA. For aim 1, the effects of adoptive transfer of Treg/CD4+ cells on cytotoxic activity of NK cells and differentiation of T-lymphocytes will be examined in murine BA, and Treg suppression of cytokine production in circulating T-lymphocytes will be studied in infants with BA and in healthy controls. For aim 2, the roles of dendritic cells, TGF? and IL10 as cellular and cytokine mediators of Treg suppression will be investigated using knockout and reporter transgenic mice, cell transplantation experiments, cytokine neutralizing antibodies, and co-culture assays measuring the stimulatory capacity of dendritic cells. Preliminary results of up-regulation of B7-molecules on hepatic dendritic cells in infants with BA will be validated in a larger cohort. For aim 3, the influence of CXCR3 on Treg-migration to the liver will be elucidated in adoptive transfer experiments and by determining the functional profile of circulating and hepatic Tregs in BA subjects and controls. Collectively, the complementary studies in mice and tissue of infants with BA will identify key regulatory pathways by which Tregs control pathogenesis of disease, guide future therapies to block the progression of biliary injury, and improve long term outcomes in children.

描述（由申请人提供）：胆道闭锁（BA）是肝外胆道树的渐进性炎性障碍，是全球小儿肝移植的最常见指示。它独特地局限于新生儿早期，轮状病毒（RRV）感染仅在生命的前3天注射时才导致小鼠的BA。我们已经报道说，在这段时间内，肝脏中没有调节性T细胞（TREG），但是在受RRV诱导的BA受保护的老年小鼠中，RRV挑战迅速出现。在初步研究中，我们已经表明，在RRV接种之前，含Treg的CD4+细胞的收养转移限制了NK和CD8淋巴细胞的肝扩张，并减弱了BA表型，如较低的血清胆红素水平和降低的炎症胆管阻塞所证明。从机械上讲，这些变化与肝髓样树突状细胞上B7共刺激分子的下调有关。缺乏趋化因子受体CXCR3的CD4细胞进行的收养转移实验表明，Treg在控制肝免疫反应中局部定位至关重要。在具有BA的婴儿的样本中，我们发现循环T淋巴细胞中促炎性细胞因子产生的趋势，与没有年龄匹配对照的CXCR3相比，肝髓细胞树突状细胞上B7分子上调上调以及缺乏CXCR3表达的循环TREG表达的频率增加。基于这些数据，我们提出了一个总体假设，即Tregs通过局部控制效应子淋巴细胞激活来保护新生儿胆管损伤。该假设将以三个重叠的特定目的进行检验：1）确定Treg限制胆管损伤的机制，2）鉴定Tregs在BA中通过Tregs进行免疫调节的途径，而3）阐明了TREG运输到BA中炎症部位的分子决定因素。对于AIM 1，将在Murine BA中检查Treg/CD4+细胞对NK细胞的细胞毒性活性的影响以及T淋巴细胞的分化，以及在BA和健康的对照中，将研究循环T-淋巴细胞中TREG抑制细胞因子的产生。对于AIM 2，树突状细胞的作用，TGF？将使用敲除和报告基因转基因小鼠，细胞移植实验，中和抗体中和抗体的抑制作用和抑制剂的IL10作为TREG抑制的细胞和细胞因子介质进行研究，以及测量树枝状细胞刺激能力的共培养测定。 B7分子对BA婴儿肝树突状细胞上的上调的初步结果将在较大的队列中得到验证。对于AIM 3，将在收养转移实验中阐明CXCR3对Treg迁移到肝脏的影响，并通过确定BA受试者和对照组中循环和肝Treg的功能曲线。总体而言，对具有BA的婴儿的小鼠和组织的互补研究将确定Tregs控制疾病发病机理的关键调节途径，指导未来的疗法阻止胆道损伤的进展，并改善儿童的长期结局。