Elucidating the role of the CXCL13/CXCR5 signaling axis in Angioimmunoblastic T-Cell Lymphoma (AITL)

项目摘要/摘要 血管免疫母细胞T细胞淋巴瘤(AITL)是一种罕见的非霍奇金淋巴瘤。到目前为止， 目前还没有针对这种癌症的有针对性的治疗方法，这反映在令人沮丧的五年总存活率上 约30%的患者接受常规化疗。受累患者的临床病理分析 个人透露，趋化因子家族中的一个成员-CXCL13-在体内持续上调 肿瘤组织，它现在被用作疾病的诊断标记。受体的同源基因 CXCL13，CXCR5，是一种G蛋白偶联受体，表达于B淋巴细胞和 CD4+T淋巴细胞的一小部分，称为卵泡辅助T细胞(TFH)。TFH细胞被认为是 AITL中起源的肿瘤细胞，作为AITL的基因特征，已被证明富含 是这些细胞的标记，包括CXCL13。这种趋化因子是B细胞募集到 生发中心和B细胞在正常生理环境下的激活。在AITL，有迹象表明 CXCL13的异常表达可能通过与TFH细胞上的CXCR5结合而激活自分泌反馈环， 可能有助于它们的增殖和存活；CXCL13也被认为导致B细胞在 癌症，导致它们分泌效应分子，导致卵泡树突状细胞(FDC)增殖 并侵入肿瘤组织。然后，人们认为FDCs与肿瘤中的T细胞密切相关， 促进TFH表型。这些自分泌和正反馈环路可能会被 CXCL13/CXCR5信号轴。我们实验室认为，阻断CXCR5可能是一种有效的 针对AITL患者的靶向治疗。 AITL的小鼠模型可用于基础研究-这些小鼠在AITL中表现出点突变 称为Roquin的信使核糖核酸结合蛋白。这种所谓的Sanroque突变(即Roquinsan/+)的杂合性 基因)导致小鼠发生肿瘤，表现出诊断为AITL的组织学特征。我们建议 探讨CXCR5‘S在本病发病机制中的作用，并作为本病的治疗靶点。的两个目标 本研究的目的是：1.通过N-脱氧核糖核酸开发一种CXCR5拮抗剂，用于Roquinsan/+小鼠体内研究。 CXCL13的末端修饰，这是一种将趋化因子从激动剂转化为拮抗剂的常见技术； 2.在Roquinsan/+背景下构建并鉴定了由CD4启动子驱动的可诱导CXCR5基因敲除。 这些研究将提供对CXCL13/CXCR5轴在AITL中所起作用的正式理解，以及 可作为开发针对人类CXCR5的生物治疗的原则证据，用于 诊所。

Project Summary/Abstract Angioimmunoblastic T-Cell Lymphoma (AITL) is a rare type of non-Hodgkin lymphoma (NHL). To date, there are no targeted therapies for the cancer, which is reflected in a dismal five-year overall survival rate at around 30% following conventional chemotherapeutic regimens. Clinicopathological analysis of affected individuals has revealed that a member of the chemokine family—CXCL13—is consistently upregulated in neoplastic tissues, and it is now used as a diagnostic marker for the disease. The cognate receptor for CXCL13, CXCR5, is a G protein-coupled receptor (GPCR) that is expressed on B lymphocytes as well as a small subset of CD4+ T lymphocytes known as Follicular Helper T cells (TFH). TFH cells are believed to be the neoplastic cell of origin in AITL, as the gene signature of AITL has been shown to be enriched in genes that are markers for these cells, including CXCL13. This chemokine is necessary for B cell recruitment into germinal centers and for B cell activation in a normal physiological setting. In AITL, there is indication that aberrant expression of CXCL13 may activate an autocrine feedback loop by binding to CXCR5 on TFH cells, possibly contributing to their proliferation and survival; CXCL13 is also thought to cause B cell activation in the cancer, leading to their secretion of effector molecules that cause Follicular Dendritic Cell (FDC) proliferation and invasion into the tumorous tissues. FDCs are then thought to intimately associate with T cells in the tumor, promoting the TFH phenotype. These autocrine and positive feedback loops could be blocked by antagonism of the CXCL13/CXCR5 signaling axis. Our lab believes that blockade of CXCR5 may serve as an effective targeted therapeutic for patients with AITL. A mouse model of AITL is available for use in basic research—these mice exhibit a point mutation in an mRNA-binding protein known as Roquin. Heterozygosity for this so-called “sanroque” mutation (i.e., Roquinsan/+ genotype) causes mice to develop tumors that display histologic features diagnostic of AITL. We propose to discern CXCR5's role in disease pathogenesis and use as a therapeutic target for the disease. The two aims of this proposal are: 1. Develop a CXCR5 antagonist biotherapeutic for in vivo studies in Roquinsan/+ mice via N- terminal modification of CXCL13, a common technique to convert chemokines from agonists into antagonists; 2. Generate and characterize a CD4 promoter-driven inducible CXCR5 knockout in the Roquinsan/+ background. These studies will provide a formal understanding of the role that the CXCL13/CXCR5 axis plays in AITL, and may serve as a proof-of-principle for development of a biotherapeutic targeting CXCR5 in humans for use in the clinic.