PLC?s in B cell biology and autoimmunity

B 细胞生物学和自身免疫中的 PLC

• 批准号: 7505428
• 负责人: DEMIN WANG
• 金额: $ 40万
• 依托单位: VERSITI WISCONSIN, INC.
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-15 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7505428
• 关键词: 76-kDa SH2 domain-containing leukocyte protein; Affect; Alleles; Apoptosis; Autoantigens; Autoimmune Diseases; Autoimmune Process; Autoimmunity; B cell repertoire; B-Cell Development; B-Lymphocytes; BLNK gene; Cell Maturation; Cellular biology; Cessation of life; Clonal Deletion; Complex; DNA Sequence Rearrangement; Data; Development; Disease; Embryo; Ensure; Enzymes; Excision; Exclusion; Genes; Immunoglobulins; Immunologic Deficiency Syndromes; Individual; LCP2 gene; Lead; Ligation; Light; Lipids; Lymphopoiesis; MAPK14 gene; MAPK8 gene; Mature B-Lymphocyte; Mediating; Molecular; Mus; Pathogenesis; Pathway interactions; Phospholipase; Play; Positioning Attribute; Process; Protein Isoforms; Protein Tyrosine Kinase; Public Health; Receptor Signaling; Regulation; Research; Residual state; Role; Self Tolerance; Signal Pathway; Signal Transduction; Signaling Molecule; Specificity; Staging; System; Testing; Transgenic Organisms; adapter protein; anergy; autoreactive B cell; mouse model; novel; pre-B cell receptor; progenitor; rap1 GTP-Binding Proteins; rap1A GTP-Binding Protein; receptor

DESCRIPTION (provided by applicant): Early B cell development and late B cell maturation are regulated by signals emanating from the pre-B cell receptor (BCR) and BCR, respectively. During maturation, B cell tolerance to self-antigens is established through clonal deletion, receptor editing and anergy, which are controlled by signals emanating from the BCR. Distorted pre-BCR/BCR signaling often results in defective B cell development, breakdown of B cell tolerance and development of immunodeficiency and autoimmune diseases. Signals from the pre-BCR/BCR that regulate B cell development and tolerance are not fully understood. Phospholipase C3 (PLC3) is an important lipid enzyme involved in pre-BCR/BCR signaling. PLC3 has two isoforms, PLC31 and PLC32. PLC32-deficient mice are viable and have impaired early and late B development. Our recent data find that PLC32 plays an important role in activation of light chain loci, editing of self-reactive receptors and induction of B cell anergy. PLC31 deficiency results in early embryonic death at midgestation, precluding analysis of its role in B cell development. However, our studies of PLC32-deficient mice that are heterozygous for PLC31-deficiency (PLC31PLC32-/-) indicate that PLC31 also plays an important role in B development. We have recently generated mice in which the PLC31 gene can be conditionally inactivated. With the mice that have genetically modified PLC31 and PLC32 genes, we are well-positioned to further study the individual and combined roles of PLC31/PLC32 in B lymphopoiesis, including tolerance establishment, and the mechanism by which both PLC3s regulate the process. We hypothesize that both PLC31 and PLC32 play an important role in pre- BCR/BCR-mediated functions and in establishing B cell tolerance. To test our hypothesis, we propose three specific aims. We will 1) determine the role of PLC31 and combined roles of PLC31 and PLC32 in pre- BCR-mediated early B cell development, allelic exclusion of IgH chain, activation of the IgL chain loci, and formation of the B cell repertoire, 2) determine the individual and combined roles of PLC31 and PLC32 in BCR- mediated B cell maturation, receptor editing and induction of anergy in B cells, and 3) study the upstream and downstream pathways of PLC31 and PLC32 during pre-BCR/BCR signaling. The proposed research seeks to understand the roles for the two PLC3 isoforms in B lymphopoiesis, especially tolerance establishment, and the mechanism by which they relay the signals from the pre-BCR/BCR. The study may provide new clues to the molecular pathogenesis of autoimmune diseases and help identify targets for specific therapies. PUBLIC HEALTH RELEVANCE This proposal seeks to understand the roles of two important signaling molecules PLC31 and PLC32 in the development of B lymphocytes, including the removal of autoreactive B cells, and the molecular mechanism by which PLC3s regulate these processes. The study may provide new clues to the molecular pathogenesis of autoimmune and immunodeficiency diseases, and help identify novel targets for specific therapies.

描述（由申请方提供）：早期B细胞发育和晚期B细胞成熟分别由前B细胞受体（BCR）和BCR发出的信号调节。在成熟过程中，B细胞对自身抗原的耐受性通过克隆缺失、受体编辑和无反应性来建立，这些都由BCR发出的信号控制。扭曲的前BCR/BCR信号传导通常导致缺陷的B细胞发育、B细胞耐受性的破坏以及免疫缺陷和自身免疫性疾病的发展。来自前BCR/BCR的调节B细胞发育和耐受性的信号尚未完全了解。磷脂酶C3（PLC 3）是一种重要的脂质酶，参与前BCR/BCR信号传导。PLC 3有两种亚型，PLC 31和PLC 32。PLC 32缺陷型小鼠存活，早期和晚期B发育受损。我们最近的数据发现PLC 32在轻链位点的激活、自身反应性受体的编辑和B细胞无反应性的诱导中起重要作用。PLC 31缺陷导致妊娠中期的早期胚胎死亡，排除了对其在B细胞发育中作用的分析。然而，我们对PLC 31缺陷杂合子（PLC 31 PLC 32-/-）的PLC 32缺陷小鼠的研究表明PLC 31在B发育中也起重要作用。我们最近已经产生了小鼠，其中PLC 31基因可以有条件地失活。利用具有遗传修饰的PLC 31和PLC 32基因的小鼠，我们处于有利地位以进一步研究PLC 31/PLC 32在B淋巴细胞生成中的单独和组合作用，包括耐受性建立，以及PLC 3s调节该过程的机制。我们假设PLC 31和PLC 32在前BCR/BCR介导的功能和建立B细胞耐受性中起重要作用。为了验证我们的假设，我们提出了三个具体目标。我们将1）确定PLC 31的作用以及PLC 31和PLC 32在前BCR介导的早期B细胞发育、IgH链的等位基因排斥、IgL链基因座的活化和B细胞库的形成中的组合作用，2）确定PLC 31和PLC 32在BCR介导的B细胞成熟、受体编辑和B细胞中无反应性的诱导中的单独和组合作用，3）研究PLC 31和PLC 32在pre-BCR/BCR信号传导中的上下游通路。拟进行的研究旨在了解两种PLC 3亚型在B淋巴细胞生成中的作用，特别是耐受建立，以及它们传递前BCR/BCR信号的机制。这项研究可能为自身免疫性疾病的分子发病机制提供新的线索，并有助于确定特定治疗的靶点。公共卫生相关性本提案旨在了解两种重要信号分子PLC 31和PLC 32在B淋巴细胞发育中的作用，包括清除自身反应性B细胞，以及PLC 3s调节这些过程的分子机制。这项研究可能为自身免疫性和免疫缺陷性疾病的分子发病机制提供新的线索，并有助于确定特异性治疗的新靶点。