Mechanisms for Latent TGF-beta1 Activation In Vivo

体内潜在 TGF-β1 激活机制

• 批准号: 8021813
• 负责人: DANIEL B RIFKIN
• 金额: $ 43.51万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8021813
• 关键词: Affect; Age; Apoptosis; Autoimmune Diseases; Binding; Binding Proteins; Biochemical; Biochemistry; Biological; Biological Models; Biology; Breeding; Cell Cycle; Cell Line; Cell Proliferation; Cells; Cellular biology; Cessation of life; Cleaved cell; Colon; Complex; Cysteine; Development; Disease; Ensure; Epithelial; Epithelial Cells; Epithelium; Fibrosis; Gastric Adenocarcinoma; Gastrointestinal Neoplasms; Gastrointestinal tract structure; Gene Proteins; Genes; Genetic; Genotype; Grant; Helicobacter; In Vitro; Infection; Inflammation; Inflammatory; Inflammatory Response; Integrins; Laboratories; Malignant Neoplasms; Marrow; Measures; Mediating; Minor; Monitor; Mus; Mutant Strains Mice; Neoplasms; Organ; Pharmacologic Substance; Phenotype; Prevention; Process; Production; Protein Binding; Proteins; Role; Serine; Signal Transduction; Stomach; Stomach Neoplasms; System; Testing; Therapeutic Intervention; Time; Tissues; Transforming Growth Factors; Tumor Suppression; Vascular Diseases; Work; cell growth; cytokine; design; dimer; disulfide bond; human TGFB1 protein; in vivo; inhibitor/antagonist; insight; interest; mutant; novel; null mutation; public health relevance; receptor; reconstitution; rectum/anus; research study; response; single molecule; tumor; tumorigenesis

DESCRIPTION (provided by applicant): TGF-? is released from cells primarily as a large latent complex (LLC) consisting of the TGF-? homodimer, the TGF-? propeptide dimer, and a single molecule of the latent TGF-? binding protein (LTBP), which is disulfide bonded to each of the propeptide chains. The propeptide, which remains associated with TGF-? even though the bond between propeptide and TGF-? has been cleaved, renders the TGF-? latent. TGF-? must be freed from the LLC to bind to its receptors. The LLC is believed to be the biologically significant form of the cytokine. A minor fraction of the latent TGF-? is secreted complexed to its propeptide in the absence of LTBP. This form is called the small latent complex (SLC). The functional differences between the LLC and SLC of latent TGF-?, which differ only by the presence or absence of LTBP, are unknown. To interrogate the functions of the SLC, we generated mutant mice (Tgfb1C33S/C33S and Tgfb1-/C33S) in which the cysteines in the TGF-?1 propeptide that bind to LTBP were replaced by serines. This mutant TGF-?1 propeptide cannot bind to LTBP. Thus, none of the secreted latent TGF-?1 is bound to an LTBP, but both LTBP and TGF-?1 complexed to its propeptide (SLC) are secreted normally. Tgfb1C33S/C33S mice have multi- organ inflammation, develop tumors of the stomach, colon, rectum and anus, and die by 3-4 months. This phenotype resembles that of the Tgfb1-/- mouse except that the Tgfb1C33S/C33S inflammatory phenotype is milder but the tumor phenotype stronger than the Tgfb1-/- phenotypes. Interestingly, 100% of Tgfb1-/C33S mice develop gastric adenocarcinomas by 12 weeks of age and have a stronger inflammatory response compared to Tgfb1C33S/C33S mice. These results indicate 1) that LTBP binding to the TGF-? propeptide is important for proper TGF-? function, 2) that there are mechanisms to activate the latent TGF-? propeptide complex in the absence of LTBP, and 3) that Tgfb1C33S/C33S and Tgfb1-/C33S mice provide a new model system to study the role of TGF-? in GI tumor induction. Using Tgfb1C33S/C33S and Tgfb1-/C33S mice in the experiments described in this application, we will establish what are the activators for the SLC, the contribution of inflammation to tumor production - specifically gastric adenocarcinomas, the changes in cell proliferation and apoptosis in the GI epithelium, and the biochemical interactions between the epithelium and stroma during gastric tumor development. We will use a combination of mouse genetics, cell biology, and biochemistry to answer these questions. The successful completion of the proposed experiments will provide information critical to the understanding of the control of TGF-? action. Such information may yield insights for therapeutic intervention or prevention of pathological conditions, such as fibrosis, cancer, and autoimmune disease that arise from inappropriate activation and activity of TGF-?. PUBLIC HEALTH RELEVANCE: Understanding how the activation of latent TGF-? is controlled may have impact into treating conditions, such as fibrosis, in which excess latent TGF-? activation occurs. Our earlier observation that the integrin subunit ?6 is involved in latent TGF-? activation has initiated work in several pharmaceutical companies to make inhibitors of ?v?6 mediated TGF-? formation. In addition, the mutant mice we have produced provide a novel system for the study of the rapid formation of gastric adenocarcinomas.

描述（申请人提供）：TGF-？主要是由TGF-组成的大型潜在复合物（LLC）从细胞中释放。同二聚体，TGF-？前肽二聚体和潜在TGF-的单个分子？结合蛋白（LTBP），该蛋白二硫键粘合到每个丙肽链上。与TGF-保持相关的前肽？即使丙肽和TGF-之间的纽带？已经裂了，使TGF-？潜。 tgf-？必须从LLC中释放才能与其受体结合。 LLC被认为是细胞因子的生物学意义形式。潜在TGF-的一小部分？在没有LTBP的情况下被分泌到其丙肽中。该形式称为小型潜伏复合物（SLC）。潜在TGF-的LLC和SLC之间的功能差异仅因存在或不存在LTBP而差异。为了询问SLC的功能，我们产生了突变小鼠（TGFB1C33S/C33S和TGFB1-/C33S），其中TGF-？1与LTBP结合的丙肽中的半胱氨酸被丝氨酸取代。这种突变的TGF-？1丙肽不能与LTBP结合。因此，没有一个分泌的潜在TGF-？1与LTBP结合，但是LTBP和TGF-？1均与其丙肽（SLC）复合（SLC）是正常分泌的。 TGFB1C33S/C33S小鼠患有多器官炎症，发展为胃，结肠，直肠和肛门的肿瘤，死亡3-4个月。这种表型类似于TGFB1 - / - 小鼠的表型，除了TGFB1C33S/C33S炎症表型较轻，但肿瘤表型比TGFB1 - / - 表型强。有趣的是，与TGFB1C33S/C33S小鼠相比，TGFB1-/C33S小鼠的100％在12周龄的年龄较高12周时会发育胃腺癌。这些结果表明1）LTBP与TGF-的结合？进型对于适当的TGF-很重要？功能，2）有一些机制激活潜在的TGF-？在没有LTBP的情况下，丙肽复合物和3）TGFB1C33S/C33S和TGFB1-/C33S小鼠提供了一个新的模型系统来研究TGF-的作用？在GI肿瘤诱导中。 Using Tgfb1C33S/C33S and Tgfb1-/C33S mice in the experiments described in this application, we will establish what are the activators for the SLC, the contribution of inflammation to tumor production - specifically gastric adenocarcinomas, the changes in cell proliferation and apoptosis in the GI epithelium, and the biochemical interactions between the epithelium and stroma during胃肿瘤的发展。我们将使用小鼠遗传学，细胞生物学和生物化学的组合来回答这些问题。拟议的实验的成功完成将为理解TGF-的控制提供至关重要的信息。行动。此类信息可能会产生有关治疗干预或预防病理状况的见解，例如纤维化，癌症和自身免疫性疾病，这些疾病是由TGF-的不适当激活和活性引起的。公共卫生相关性：了解潜在TGF-的激活如何？受控是否可能对治疗条件（例如纤维化）产生影响，其中过量的潜在TGF-？激活发生。我们较早的观察结果是，整联蛋白亚基6参与潜在的TGF-？激活已经在几家制药公司中启动了工作，以制造抑制剂的抑制剂。6介导的TGF-？形成。此外，我们产生的突变小鼠为研究胃腺癌的快速形成提供了新的系统。