Challenging dogma: an alternative non-hierarchical, epigenetically regulated model of the urothelium.

挑战教条：另一种非等级的、表观遗传调控的尿路上皮模型。

• 批准号: BB/R006172/1
• 负责人: Jennifer Southgate
• 金额: $ 59.86万
• 依托单位: University of York
• 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=BB%2FR006172%2F1
• 关键词: Challenging; dogma; alternative; non; hierarchical

Epithelial tissues occur at the interface of internal and external surfaces of the body, where they have evolved highly specialised forms and functions. For example, the skin has evolved for physical protection and to protect against dehydration, whereas the gut has specialised to digest food and absorb nutrients. Both these epithelial tissues show constant turnover, with specialised cells being replaced by others generated by proliferation and migration from a basal progenitor or stem cell pool. The hierarchical model of cells programmed to pursue a one-way journey from a stem cell to the specialised, differentiated cell is used to explain how tissues maintain a balance (homeostasis) between cell loss and gain, and even why cancer stem cells should be targeted in cancer therapy. This project challenges this generic model of epithelial regulation and differentiation, based on observations from a different epithelial tissue, the urothelium.Urothelium is the specialised epithelium which lines the bladder and ureters and functions as a tight urinary barrier. Unlike gut or skin, there is no constant cycle of renewal: cells of the urothelium are long-lived and mitotically-quiescent, but retain the capacity to contribute to efficient urinary barrier repair and regeneration by rapid re-entry into the mitotic cycle. No specific stem cell has ever been identified in human urothelium and dividing cells can be observed in any of the three layers. Phenotypically and positionally, urothelial cells adopt one of four distinct cell types (each of which we can isolate). Current molecular knowledge is based on homogenised urothelial preparations and therefore lacks sufficient subtype-specific detail. Our hypothesis is that rather than being part of a linear differentiation programme, urothelial cells display the appropriate phenotype in response to exogenous cues or their "niche" within the tissue, including adaptation to change (eg damage). Our hypothesis predicts an intimate relationship between epigenetic and signal transduction machineries to effect changes in cell phenotype. We will test our hypothesis using urothelium from the ureter and the bladder for comparison, as these are of different embryological derivations. From each source, we will isolate, to high purity, each of the four distinct urothelial cell phenotypes and perform an in depth characterisation of the transcriptome and epigenome of each subtype to determine differences and similarities. We will also analyse the separated cell types after adaptation to a non-permissive cell culture system where we predict that all cells will adopt a baseline or default reference squamous phenotype irrespective of derivation. We will use the cell culture system to investigate the signals of each "niche" and test how altering different regulatory pathways can modify cell phenotype, where we predict that the epigenetic machinery will play a hitherto unrecognised key role that can be manipulated and exploited. A deliverable from this project will be a data-rich, spatially-resolved urothelial map of the regulatory networks and machinery that defines the different urothelial subtypes. The outcome of this study will be important new understanding of urothelial tissue homeostasis that will challenge longstanding models of tissue biology and bring new perspectives to chronic diseases of ageing that affect the bladder, including future therapeutic opportunities in tissue engineering and regenerative medicine.

上皮组织发生在身体内外表面的界面处，在那里它们已经进化出高度专门化的形式和功能。例如，皮肤已经进化为物理保护和防止脱水，而肠道专门消化食物和吸收营养。这两种上皮组织都显示出恒定的更替，特化细胞被从基底祖细胞或干细胞库增殖和迁移产生的其他细胞所取代。细胞的层次模型被编程为追求从干细胞到特化分化细胞的单向旅程，用于解释组织如何在细胞损失和获得之间保持平衡（稳态），甚至为什么癌症干细胞应该在癌症治疗中被靶向。该项目挑战了上皮调节和分化的一般模型，基于对不同上皮组织（尿道上皮）的观察。尿道上皮是专门的上皮，衬在膀胱和输尿管上，起着紧密的泌尿屏障的作用。与肠道或皮肤不同，没有恒定的更新周期：尿路上皮细胞寿命长，有丝分裂静止，但保留了通过快速重新进入有丝分裂周期来促进有效的尿屏障修复和再生的能力。在人类尿路上皮中还没有发现特定的干细胞，在三层中的任何一层都可以观察到分裂细胞。在表型和位置上，尿路上皮细胞采用四种不同的细胞类型之一（我们可以分离出每一种）。目前的分子知识是基于均质化的尿路上皮制剂，因此缺乏足够的亚型特异性细节。我们的假设是，而不是一个线性分化程序的一部分，尿路上皮细胞显示适当的表型响应外源性线索或其组织内的“生态位”，包括适应变化（如损伤）。我们的假设预测了表观遗传和信号转导机制之间的密切关系，以影响细胞表型的变化。我们将使用输尿管和膀胱的尿路上皮作为比较来检验我们的假设，因为它们是不同的胚胎学来源。从每个来源，我们将分离，以高纯度，每四个不同的尿路上皮细胞表型，并执行每个亚型的转录组和表观基因组的深入表征，以确定差异和相似性。我们还将分析适应非许可细胞培养系统后分离的细胞类型，在该系统中，我们预测所有细胞将采用基线或默认参考鳞状细胞表型，而不考虑来源。我们将使用细胞培养系统来研究每个“生态位”的信号，并测试如何改变不同的调控途径可以修改细胞表型，我们预测表观遗传机制将发挥迄今未被认识到的关键作用，可以操纵和利用。该项目的一个可交付成果是定义不同尿路上皮亚型的调控网络和机制的数据丰富、空间分辨的尿路上皮地图。这项研究的结果将是对尿路上皮组织稳态的重要新认识，这将挑战长期存在的组织生物学模型，并为影响膀胱的慢性衰老疾病带来新的视角，包括组织工程和再生医学的未来治疗机会。

项目成果

Additional file 3: of Increased DNA methylation variability in rheumatoid arthritis-discordant monozygotic twins

附加文件 3：类风湿性关节炎不一致的同卵双胞胎中 DNA 甲基化变异性增加

• DOI: 10.6084/m9.figshare.7040618
• 发表时间: 2018
• 作者: Webster A

Increased DNA methylation variability in rheumatoid arthritis-discordant monozygotic twins.

• DOI: 10.1186/s13073-018-0575-9
• 发表时间: 2018-09-04
• 期刊: Genome medicine
• 影响因子: 12.3
• 作者: Webster AP;Plant D;Ecker S;Zufferey F;Bell JT;Feber A;Paul DS;Beck S;Barton A;Williams FMK;Worthington J
• 通讯作者: Worthington J