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-gamma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。我们已经使用了一种生物信息学方法来识别干扰素γmRNA的3'未翻译部分的保守区域。人们认为，这些保守的区域代表基因结构中的重要调节元素，因为除非mRNA的非编码区域提供了一定的进化优势，否则不会通过进化来保护固有的区域。基于此分析，我们针对鼠干扰素3'未翻译区域的160 bp区域以缺失，因为该区域富含AUUA序列，并且此类区域先前已被证明对细胞因子基因表达的调节很重要。敲除（KO）小鼠已成功地在C57 BL/6遗传背景上创建，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处理后产生的干扰素γ明显更大。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。由于存在CD4+和CD8+ T细胞增加，并且小鼠中的T Reg细胞具有更有效的抑制活性，因此T细胞稳态受到了破坏。 TH1反应也增加，TH2对抗原刺激的反应减少。 B细胞群也会改变，基线抗体的产生偏斜。在胸腺中还观察到B细胞的频率增加，因此表明IFN-GAMMA可能会改变B细胞的运输。除表型后果外，由于IgM增加和Ig2a AB反应的增加，IgG1响应的降低也会破坏B细胞对抗原的反应。还观察到了强抗DNA和抗核抗原抗体反应，表明慢性IFN-GAMMA表达可能在狼疮的发育中起作用。奇怪的是，在BALB/C小鼠中看不到类似狼疮的症状，那里的160 bp缺失也已跨越了该遗传背景。这些小鼠的脾脏大小增加，淋巴细胞流量到淋巴结的明显缺陷。这导致表型与性障碍性贫血非常相似，我们正在阐明IFN-gamma在该疾病发展中的作用。这些作用似乎是该小鼠菌株中对造血祖细胞的干扰素γ抑制干扰素γ的直接结果。此外，带有缺失的BALB/C小鼠似乎对肾脏癌系Renca的挑战更具抵抗力。总而言之，我们阐明干扰素伽马生物学涉及多种机制的方法证明了干扰素 - 伽马基因表达改变宿主稳态的复杂性。此外，我们现在已经开发了一种小鼠模型，以理解和阐明长期慢性IFN-GAMMA基因表达的系统生物学影响。