Decoding senescent cell signalling pathways in tissue fibrosis

慢性肾脏病(CKD)影响全球超过7亿人，更常见于老年患者和先前急性肾脏损伤的幸存者。治疗选择有限，尽管目前最大限度的药物治疗，慢性肾脏病仍经常进展。对阻止CKD典型进行性瘢痕形成的新疗法的需求尚未得到满足。我之前的工作表明，在人类CKD中，衰老细胞(SCs)的数量增加，在肾脏损伤和衰老的动物模型中，SCs的存在促进了进行性瘢痕形成和功能丧失。我们的研究还表明，杀死衰老细胞的治疗方法可以提高较老的和先前受损的肾脏在进一步损伤后再生的能力。我推测，抑制慢性衰老细胞(SCs)中的信号通路将通过防止它们对瘢痕形成的影响和促进它们的清除，提供一种更精确的方式来保护肾脏的结构和功能。为此，我们将首先检查患有慢性肾脏病的人肾脏样本，并使用新的高分辨率技术来探索干细胞在单细胞分辨率下的行为-确定哪些途径将干细胞与纤维化、炎症和更糟糕的长期结果的产生联系起来。接下来，我们将利用先进的芯片上器官培养环境剖析干细胞衍生途径对炎症细胞和疤痕产生细胞的影响，这将使我们能够梳理出到底哪些途径解释了干细胞抵抗免疫细胞清除的能力，以及干细胞如何直接或间接导致纤维化以一种在整个肾脏中不可能发生的方式产生。然后，我们将与爱丁堡药物发现部门的同事合作，利用他们的专业知识对数千种潜在的药物化合物进行高效、自动化的测试-寻找可以抑制我们在早期工作中确定的致病途径的药物，并选择性地促进干细胞的失活和/或清除，而不会对健康细胞产生副作用。接下来，我们将测试旨在防止干细胞导致的肾脏瘢痕形成的治疗方法的安全性和有效性，同时促进干细胞在小鼠肾脏纤维化模型中的健康清除。我们将使用一种品系的小鼠，其中的干细胞可以用两种不同的荧光颜色进行标记，这为我们提供了额外的信息，即在最初的损伤后，干细胞的行为是否会随着时间的延长而有所不同。我们将能够检查我们的药物对SC数量和行为的影响，以及免疫细胞和成纤维细胞(导致肾脏内形成疤痕的细胞类型)行为的影响，衡量每种药物在受伤后保护肾脏功能的效果。最后，我们将把我们的工作从替补席转移到人类肾脏上--人类肾脏已经被提供给移植，但被认为不适合重新移植。使用机械来保持肾脏的活力、温度和氧气，我们将实施并观察我们在人类肾脏中表现最好的靶向抗SC疗法的安全性和有效性，为早期转化为临床研究奠定基础。

Chronic kidney disease (CKD) affects over 700 million people worldwide and is more common in older patients and survivors of previous acute kidney injury. Treatment options are limited, and CKD often progresses despite maximal current medical therapy. There is an unmet need for novel treatments to halt the progressive scarring typical of CKD.My previous work has shown that senescent cells ("SCs" - altered, permanently growth-arrested cells) are present in increased numbers in human CKD, and that in animal models of kidney injury and ageing, the presence of SCs promotes progressive scarring and functional loss. Our studies also showed that treatments that kill senescent cells improve the ability of older and previously damaged kidneys to regenerate after further injuries. I hypothesise that inhibiting signalling pathways in chronic senescent cells (SCs) will provide a more precise way to preserve renal structure and function by preventing their effects on scarring and promoting their clearance. To do this, we will first examine samples of human kidneys with CKD - and use new, high-resolution techniques to explore SC behaviour at single cell resolution - identifying which pathways connect SCs to the production of fibrosis, inflammation and worse long term outcomes.Next, we will dissect out the influence of SC derived pathways on inflammatory cells and on scar producing cells using an advanced 'organ-on-a-chip' cell culture environment which will allow us to tease out exactly which pathways account for the ability of SCs to resist clearance by immune cells, and how SCs directly or indirectly cause fibrosis to be produced in a way not possible in a whole kidney. In collaboration with our colleagues in the Edinburgh Drug Discovery Unit we will then use their expertise to perform highly efficient, automated testing of thousands of potential drug compounds - looking for agents which inhibit the pathways we have identified as causative in our earlier work - and which selectively promote inactivation and/or clearance of SCs without side effects on healthy cells.We will next test the safety and efficacy of treatments designed to prevent SC driven kidney scarring, whilst promoting the healthy clearance of SCs in mouse models of kidney fibrosis. We will use a strain of mouse where SCs can be labelled with two different fluorescent colours, giving us additional information on whether SCs behave differently the longer they persist after initial injury. We will be able to examine the effects of our drugs on SC number and behaviour, as well as immune cell and fibroblast (the type of cell responsible for the production of scarring within the kidney) behaviour, measuring how well each drug protects the function of the kidney after injury. Finally, we will move our work from bench back to human kidneys - which have been offered for transplantation but deemed unsuitable for re-implantation. Using machinery to keep the kidneys alive, warm and oxygenated we will administer and observe the safety and efficacy of our best-performing targeted anti-SC therapy in the human kidney, setting the stage for early translation to clinical studies.