Exploitation of metadherin as a regulator of hepatic energy metabolism

利用麦粘蛋白作为肝脏能量代谢的调节剂

• 批准号: MR/P011853/2
• 负责人: David Ray
• 金额: $ 43.13万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FP011853%2F2
• 关键词: Exploitation; metadherin; regulator; hepatic; energy

The metabolic syndrome, a collection of obesity, hepatic steatosis, and insulin resistance is a major public health crisis, with unmet medical need. Non-surgical intervention strategies including lifestyle modification are generally ineffective due to poor compliance. We must therefore continue to identify and develop novel strategies and therapeutic targets. An essential initiating feature is excess triglyceride accumulation in the liver, which can progress through inflammation and fibrosis to steatohepatitis, cirrhosis, and hepatocellular carcinoma. Glucocorticoid (Gc) signalling in the liver has been implicated at all stages of progression. Moreover, metabolic complication is a persistent and limiting issue in long-term Gc treatment in inflammatory disease.In seeking mechanisms to address metabolic complications of Gc action we discovered the Gc receptor (GR) binds to metadherin, a multifunctional protein scaffold, implicated in liver lipid metabolism, inflammation and cancer. We discovered that metadherin is essential for Gc transactivation, but not transrepression, and that this is accomplished by regulating GR recruitment to enhancer elements. In mice lacking metadherin, Gc action in the liver was profoundly altered with a major shift in Gc-responsive lipid metabolic genes, and also a striking hyperglycaemic response. In the metadherin null mice, we also observed genome wide changes in H3K27Ac, a mark of active enhancers, in response to acute Gc challenge; likely indicating an underlying re-wiring of the GR cistrome. We have established mouse models of glucocorticoid excess, and found a marked induction of hepatic triglyceride, with lipid droplet accumulation; thus optimising a model of Gc-induced hepatosteatosis. We will now use this mode and more conventional diet-induced obesity, to define control mechanisms in GR action, and the role of metadherin.We will define how metadherin regulates GR function. We have evidence that metadherin promotes interaction with kinases required to modify the GR. We will now comprehensively define post-translational modification, using new mass spectrometry approaches, and link receptor modification to function. As altered GR trafficking (as may explain failure of recruitment to enhancers in response to metadherin disruption), we will employ single molecule resolution live cell imaging to track GR movement, and use fluorescence correlation spectroscopy to measure interaction with metadherin in real time.We hypothesise that metadherin, a known scaffold protein, promotes protein-protein interaction to regulate cellular responses to environmental stress, such as energy excess in the liver. To find metadherin effector mechanisms, we will define post-translational dynamics of metadherin, and use proteomics to identify metadherin client proteins, and in normal and fatty liver. We will specifically measure interactions with the 36 liver-expressed nuclear receptors, using a targeted, quantitative mass spectrometry approach.Finally, we will examine the physiological consequence of metadherin action in vivo with selective genetic targeting of metadherin in hepatocytes in mice under normal conditions and during diet-induced obesity and chronic Gc treatment. Together, this programme of work will define a new regulatory mode in Gc signaling and reveal a potential new therapeutic target ,which has the intriguing potential to selectively modify metabolic consequence of GR action.

代谢综合征是肥胖、肝脂肪变性和胰岛素抵抗的集合，是一个重大的公共卫生危机，医疗需求未得到满足。由于依从性差，包括生活方式改变在内的非手术干预策略通常无效。因此，我们必须继续确定和开发新的战略和治疗目标。一个基本的起始特征是肝脏中过量的甘油三酯积累，其可以通过炎症和纤维化进展为脂肪性肝炎、肝硬化和肝细胞癌。肝脏中的糖皮质激素（Gc）信号传导在进展的所有阶段都有牵连。此外，代谢并发症是一个持久的和限制性的问题，在长期的Gc治疗炎症性疾病，在寻找机制，以解决Gc作用的代谢并发症，我们发现Gc受体（GR）结合到metadherin，一个多功能的蛋白质支架，涉及肝脏脂质代谢，炎症和癌症。我们发现，metadherin是必不可少的GC反式激活，但不是反式阻遏，这是通过调节GR招聘增强子元件。在缺乏metadherin的小鼠中，GC在肝脏中的作用发生了深刻的改变，GC反应性脂质代谢基因发生了重大变化，并且也发生了显著的高血糖反应。在metadherin敲除小鼠中，我们还观察到H3 K27 Ac（活性增强子的标记）响应于急性Gc攻击的全基因组变化;这可能表明GR顺式组的潜在重新布线。我们已经建立了糖皮质激素过量的小鼠模型，并发现了一个显着的诱导肝甘油三酯，与脂滴积累，从而优化GC诱导的肝脂肪变性模型。我们现在将使用这种模式和更传统的饮食诱导的肥胖症，以确定控制机制的GR行动，和metadherin的作用。我们将确定metadherin如何调节GR功能。我们有证据表明，metadherin促进相互作用所需的激酶修改GR。我们现在将全面定义翻译后修饰，使用新的质谱方法，并链接受体修饰功能。作为改变的GR贩运（这可能解释了响应于元粘附素破坏而募集到增强子的失败），我们将采用单分子分辨率活细胞成像来跟踪GR运动，并使用荧光相关光谱来测量与元粘附素的真实的相互作用。我们假设元粘附素是一种已知的支架蛋白，促进蛋白质-蛋白质相互作用以调节细胞对环境应激的反应，比如肝脏能量过剩为了找到metadherin效应机制，我们将定义metadherin的翻译后动力学，并使用蛋白质组学来识别metadherin客户蛋白，并在正常和脂肪肝。我们将专门测量与36个肝脏表达的核受体的相互作用，使用有针对性的，定量mass spectrometry approach.Finally，我们将检查metadherin在体内的作用的生理后果，在正常条件下，在饮食诱导的肥胖和慢性GC治疗期间，在小鼠肝细胞中选择性遗传靶向metadherin。总之，这项工作计划将定义一种新的Gc信号转导调控模式，并揭示一个潜在的新的治疗靶点，它具有选择性地改变GR作用的代谢结果的有趣潜力。

项目成果

Caveolin1 interacts with the glucocorticoid receptor in the lung but is dispensable for its anti-inflammatory actions in lung inflammation and Trichuris Muris infection.

Caveolin1 与肺部的糖皮质激素受体相互作用，但其在肺部炎症和鞭毛虫感染中的抗炎作用是可有可无的。

• DOI: 10.1038/s41598-019-44963-0
• 发表时间: 2019
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Caratti G

Circadian variation in pulmonary inflammatory responses is independent of rhythmic glucocorticoid signaling in airway epithelial cells.

• DOI: 10.1096/fj.201800026rr
• 发表时间: 2019-01
• 期刊: FASEB journal : official publication of the Federation of American Societies for Experimental Biology
• 作者: Ince LM;Zhang Z;Beesley S;Vonslow RM;Saer BR;Matthews LC;Begley N;Gibbs JE;Ray DW;Loudon ASI
• 通讯作者: Loudon ASI

Reply to Moitra et al. : Individual Chronotype May Confound Asthma Symptoms and Therapy

回复莫伊特拉等人。

• DOI: 10.1164/rccm.201809-1712le
• 发表时间: 2019
• 期刊: American Journal of Respiratory and Critical Care Medicine
• 影响因子: 24.7
• 作者: Durrington H

REVERBa couples the circadian clock to hepatic glucocorticoid action.

• DOI: 10.1172/jci96138
• 发表时间: 2018-10-01
• 期刊: The Journal of clinical investigation
• 作者: Caratti G;Iqbal M;Hunter L;Kim D;Wang P;Vonslow RM;Begley N;Tetley AJ;Woodburn JL;Pariollaud M;Maidstone R;Donaldson IJ;Zhang Z;Ince LM;Kitchen G;Baxter M;Poolman TM;Daniels DA;Stirling DR;Brocker C;Gonzalez F;Loudon AS;Bechtold DA;Rattray M;Matthews LC;Ray DW
• 通讯作者: Ray DW