Consequences of chronic Interferon-gamma expression on the host

慢性干扰素-γ表达对宿主的后果

• 批准号: 8937674
• 负责人: Howard Young
• 金额: $ 163.17万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8937674
• 关键词: 3' Untranslated Regions; Antibody Formation; Antigens; Aplastic Anemia; Architecture; Autoimmunity; B-Lymphocytes; Belief; Biochemical Pathway; Bioinformatics; Biological; Biology; CD8B1 gene; Cells; Chromatin; Chronic; Communicable Diseases; Complex; Cytokine Gene; DNA; DNA Methylation; Data; Defect; Development; Disease; Effector Cell; Evolution; Exhibits; Frequencies; Functional RNA; Gene Expression; Gene Structure; Genetic; Goals; Hematopoietic; Homeostasis; IgG1; Immune; Immune response; Immune system; Immunoglobulin M; Infection; Inflammation; Inflammatory; Interferon Type II; Interleukin-12; Knockout Mice; Laboratories; Laboratory Study; Liver; Long-Term Effects; Lupus; Lymphocyte; Malignant Neoplasms; Mediation; Messenger RNA; Molecular; Mouse Strains; Mus; Nuclear Antigens; Phenotype; Play; Population; Post-Transcriptional Regulation; RNA Conformation; Regulation; Regulatory Element; Renal carcinoma; Resistance; Role; Spleen; Structure; Symptoms; Systems Biology; T-Lymphocyte; Thymus Gland; Whole Organism; Wild Type Mouse; Work; base; cytokine; human disease; lupus-like; lymph nodes; mRNA Stability; mouse model; progenitor; response; trafficking; transcription factor

We are utilizing mouse models of chronic IFN-gamma expression to determine the biological consequences to the host and the relevance of this phenotype to human disease. We have used a bioinformatics approach to identify conserved regions of the 3' untranslated portion of the interferon-gamma mRNA. It is believed that these conserved regions represent important regulatory elements in the gene structure, as there would be no inherent region for conservation through evolution unless the non-coding regions of the mRNA provided some evolutionary advantage. Based on this analysis, we have targeted a 160-bp region of the murine interferon-gamma 3' untranslated region for deletion as this region is rich in AUUA sequences, and such regions have been previously shown to be important in the regulation of cytokine gene expression. The knockout (KO) mouse has been successfully created on the C57 BL/6 genetic background and our data indicates that this mouse produces significantly more interferon-gamma at a basal level and upon treatment with IL-12 as compared to the wild-type mouse. Furthermore, the architecture of lymph nodes, spleen, and thymus is disrupted and the liver exhibits signs of chronic inflammation. T cell homeostasis has been disrupted as increased CD4+ and CD8+ T cells are present and the T reg cells in the mouse have more potent suppressor activity. There is also an increased TH1 response and a decreased TH2 response to antigenic stimulation. The B cell population is also altered and baseline antibody production is skewed. B cells are also observed in the thymus at increased frequency, thus indicating that IFN-gamma may alter B cell trafficking. In addition to the phenotypic consequences, the B cell response to antigen is also disrupted as increased IgM and Ig2a ab responses are seen with a decrease in the IgG1 response. Strong anti-DNA and anti-nuclear antigen antibody responses are also observed suggesting that chronic IFN-gamma expression may play a role in the development of lupus. Curiously, lupus-like symptoms are not seen in the Balb/c mouse, where the 160-bp deletion has also been crossed onto that genetic background. These mice have increased spleen sizes and an apparent defect in lymphocyte trafficking to the lymph nodes. This results in a phenotype very similar to aplastic anemia and we are elucidating the role of IFN-gamma in the development of this disease. These effects appear to be a direct consequence of interferon-gamma inhibition of hematopoietic progenitors in this mouse strain. In addition, the Balb/c mice with the deletion appear to be more resistant to challenge with the renal carcinoma line RENCA. In summary, our approach towards elucidating the multiple mechanisms involved in the biology of interferon-gamma demonstrates the complexity by which interferon-gamma gene expression alters host homeostasis. Furthermore, we now have developed a mouse model for understanding and elucidating the systems biology effects of long term chronic IFN-gamma gene expression.

我们正在利用慢性 IFN-γ 表达的小鼠模型来确定对宿主的生物学后果以及该表型与人类疾病的相关性。我们使用生物信息学方法来鉴定干扰素-γ mRNA 3'非翻译部分的保守区域。据信，这些保守区域代表了基因结构中的重要调控元件，因为除非 mRNA 的非编码区域提供了一些进化优势，否则在进化过程中不会有固有的保守区域。基于此分析，我们针对鼠干扰素-γ 3'非翻译区的160 bp区域进行了删除，因为该区域富含AUUA序列，并且该区域先前已被证明在细胞因子基因的调节中具有重要作用表达。敲除 (KO) 小鼠已在 C57 BL/6 遗传背景上成功创建，我们的数据表明，与野生型小鼠相比，该小鼠在基础水平和 IL-12 治疗后产生显着更多的干扰素-γ 。此外，淋巴结、脾脏和胸腺的结构被破坏，肝脏表现出慢性炎症的迹象。随着 CD4+ 和 CD8+ T 细胞的增加，T 细胞稳态已被破坏，并且小鼠中的 T reg 细胞具有更有效的抑制活性。对抗原刺激的 TH1 反应增加，TH2 反应减少。 B 细胞群也发生改变，基线抗体产生发生偏差。在胸腺中也观察到 B 细胞的频率增加，因此表明 IFN-γ 可能会改变 B 细胞的运输。除了表型后果外，B 细胞对抗原的反应也被破坏，因为 IgM 和 Ig2a ab 反应增加，而 IgG1 反应减少。还观察到强烈的抗 DNA 和抗核抗原抗体反应，表明慢性 IFN-γ 表达可能在狼疮的发展中发挥作用。奇怪的是，Balb/c 小鼠中并未出现狼疮样症状，该小鼠的 160 bp 缺失也已与该遗传背景交叉。这些小鼠的脾脏尺寸增大，淋巴细胞运输至淋巴结的能力明显缺陷。这导致与再生障碍性贫血非常相似的表型，我们正在阐明 IFN-γ 在这种疾病发展中的作用。这些效应似乎是该小鼠品系中干扰素-γ抑制造血祖细胞的直接结果。此外，具有缺失的Balb/c小鼠似乎对肾癌系RENCA的攻击具有更强的抵抗力。总之，我们阐明干扰素γ生物学涉及的多种机制的方法证明了干扰素γ基因表达改变宿主稳态的复杂性。此外，我们现在开发了一种小鼠模型，用于理解和阐明长期慢性 IFN-γ 基因表达的系统生物学效应。