TOWARDS A MOUSE MODEL OF CLASSICAL HODGKIN'S DISEASE

经典霍奇金病的小鼠模型

• 批准号: 6904702
• 负责人: KLAUS RAJEWSKY
• 金额: $ 42.05万
• 依托单位: IMMUNE DISEASE INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6904702
• 关键词: B cell receptor; B lymphocyte; Epstein Barr virus; Hodgkin' s disease; apoptosis; cell proliferation; cell transformation; disease /disorder model; flow cytometry; gene expression; gene targeting; genetically modified animals; laboratory mouse; model design /development; oncogenic virus; receptor expression; terminal nick end labeling; virus antigen; virus protein

DESCRIPTION (provided by applicant): Classical Hodgkin's disease (HD) is the most common lymphoma in the Western World. The malignant cells in HD are the so-called Hodgkin and Reed-Sternberg (HRS) cells, which comprise only a few percent or less of the lymphoma tissue. In roughly half of the patients, the HRS cells are infected with Epstein-Barr-Virus (EBV) and express the EBV-encoded membrane proteins LMP1 and LMP2A. These proteins are constitutively active and in B cells partially mimic signals of the CD40 co-receptor and the antigen receptor (BCR), respectively. Based on these circumstances and on our own molecular analysis of Ig gene rearrangements in micro manipulated HRS cells we have developed a scenario of HD pathogenesis. In this scenario, HRS cells derive in most instances from pre-apoptotic germinal center (GC) B cells rescued by some transforming event(s). In EBV+ HD, LMP1 and LMP2A may participate in this initial rescue. The aim of this proposal is to reconstruct this scenario in the mouse by conditional gene targeting techniques. We have developed a mouse mutant in which Cre recombinase is efficiently expressed in GC but not naive B cells. This will be used to target expression of LMP2A and/or LMP1 to GC B cells in vivo. The interference of the viral proteins with the GC reaction will be investigated. Rescue of pre-apoptotic GC B cells that have lost BCR expression because of somatic hypermutation might be observed, as well as lymphomagenesis, given the known oncogenic properties of LMP1. These experiments will be complemented by an attempt to target another potential tumor determinant of HRS cells into GC B cells, namely the activated form of Notch1. This molecule has recently been shown to be expressed in HRS cells at high levels and in an activated form. Notch1 is particularly attractive in this context, because it is involved in lineage decisions in lymphocyte progenitors, promoting T cell development. Curiously, HRS cells have down regulated many B cell-specific genes and express molecular markers of other hematopoietic lineages, including T cells. Notch1, which is also a potent oncogene if ectopically expressed, might thus contribute to this curious phenotype as well as to HRS cell transformation. Combining LMP2A, LMP1 and Notch1 expression in GC B cells by conditional gene targeting might lead to a mouse model of HD. Apart from lymphomagenesis, the proposed experiments should also lead to new insights into the biology of the GC reaction in the context of EBV infection.

描述（由申请人提供）：古典霍奇金氏病（HD）是西方世界上最常见的淋巴瘤。 HD中的恶性细胞是所谓的Hodgkin和Reed-Sternberg（HRS）细胞，仅占淋巴瘤组织的百分之几以下。在大约一半的患者中，HRS细胞被Epstein-Barr-Virus（EBV）感染，并表达EBV编码的膜蛋白LMP1和LMP2A。这些蛋白质是组成型活性的，在B细胞中，CD40共受体和抗原受体（BCR）的部分模拟信号。基于这些情况和我们对微观操纵HRS细胞Ig基因重排的分子分析，我们开发了HD发病机理的情况。在这种情况下，HRS细胞在大多数情况下从凋亡前生发中心（GC）B细胞中得出，该细胞通过某些转化事件（S）救出。在EBV+ HD中，LMP1和LMP2A可能参与此初始救援。该建议的目的是通过条件基因靶向技术在小鼠中重建这种情况。我们已经开发了一种小鼠突变体，其中CRE重组酶在GC中有效地表达，而不是天真的B细胞。这将用于靶向LMP2A和/或LMP1的体内GC B细胞的表达。病毒蛋白对GC反应的干扰将进行研究。考虑到LMP1的已知致癌特性，可以观察到由于体细胞超数而失去BCR表达的凋亡前GC B细胞。这些实验将通过试图将HRS细胞的另一个潜在肿瘤决定因素靶向GC B细胞的尝试，即Notch1的激活形式。最近已显示该分子以高水平和活化形式的HRS细胞表达。在这种情况下，Notch1特别有吸引力，因为它参与了淋巴细胞祖细胞中的谱系决策，从而促进T细胞的发展。奇怪的是，HRS细胞减少了许多B细胞特异性基因，并表达了包括T细胞在内的其他造血谱系的分子标记。 Notch1（如果异位表达）也是一种有效的致癌基因，因此可能会导致这种奇怪的表型以及HRS细胞转化。通过条件基因靶向在GC B细胞中结合LMP2A，LMP1和NOTCH1表达可能会导致HD小鼠模型。除了淋巴作用外，在EBV感染的背景下，提出的实验还应导致对GC反应的生物学的新见解。