Reducing organ fibrosis by targeting a novel pro-fibrotic CLEC4D expressing myeloid subset.

患有肾脏和肝脏疾病的患者失去了正常的器官组织，因为它逐渐被疤痕组织取代，导致器官功能下降。最终，这可能会导致器官衰竭，患者需要接受慢性透析治疗或肾/肝移植。尽管有这些挽救生命的疗法，肾脏和肝脏疾病仍是第11和第12大死因。不幸的是，患有肾脏和肝脏疾病的患者数量继续上升，治疗选择仍然有限，因此，研究人员找到减缓疾病进展的新疗法至关重要。无论损伤的根本原因是什么，肾脏和肝脏的损伤都会导致白细胞向受损的器官募集。这些细胞是人体免疫系统的一部分，对抵抗感染很重要，但在器官损伤期间，它们可能会促进进一步的损伤和疤痕形成。我们知道，阻止这些免疫细胞向受损器官募集的药物可以减缓但不能阻止肝脏和肾脏疾病的进展。然而，免疫细胞的某些亚群可能是有益的，因为它们是正常组织功能和促进修复所必需的。因此，阻止所有免疫细胞到达受损的器官是不可取的，更有针对性的方法来抑制那些促进损伤的亚群可能更有好处。为了识别促进器官损伤的特定免疫细胞亚群，我们在肾脏和肝脏疾病的模型中采用了一种名为单细胞RNA测序的最先进技术。这使我们能够确定个体免疫细胞中哪些基因被打开或关闭。这表明，免疫细胞亚群的数量比我们之前所知道的要多得多。通过分析每个细胞中被激活的基因，我们已经确定了一组免疫细胞，它们表达了许多促进炎症和疤痕形成的基因，这让我们怀疑这一亚群可能会促进肾脏和肝脏的损伤。这一亚群中的免疫细胞表面有一种名为CLEC4D的特定蛋白质，我们相信靶向这种CLEC4D分子可能比目前的治疗方法更精确地防止器官损伤。在这个项目中，我们将使用肝和肾脏疾病患者的活检组织来检查表达CLEC4D的免疫细胞中哪些分子通路被激活。这些知识将帮助我们开发新的药物，可以防止这些细胞引起炎症和疤痕。我们的合作者已经开发出一种抗体，可以与CLEC4D结合并中和CLEC4D的作用。我们将使用临床前的肾和肝损伤模型来测试这种抗体是否可以阻止免疫细胞的激活，从而防止器官中疤痕组织的发展。如果成功，这可以用来防止肾脏和肝脏疾病患者器官的疤痕形成。此外，我们还发现CLEC4D+免疫细胞中激活了一条特定的生化途径，我们认为这有助于炎症和疤痕形成。我们将使用基因工具在免疫细胞中阻断这一途径，以在肾脏和肝脏疾病的模型中测试这一假说。这将表明，通过给药阻断这一途径是否可能是预防肾和肝瘢痕的替代方法。综上所述，我们的研究将确定一些专注于抑制特定免疫细胞亚群的补充策略是否可以减少包括肾脏和肝脏在内的器官的炎症和疤痕，以防止器官衰竭。

Patients with kidney and liver disease lose their normal organ tissue as it is progressively replaced by scar tissue, resulting in a reduction in organ function. Eventually, this may lead to organ failure and the need for patients to undergo chronic dialysis therapy or kidney/liver transplantation. Despite these life-saving therapies, kidney and liver disease are the 11th and 12th leading causes of death. Unfortunately, the number of patients with kidney and liver disease is continuing to rise and treatment options remain limited, therefore it is vitally important that researchers identify novel therapies that slow progression of disease.Regardless of the underlying cause of the injury, damage to the kidneys and liver results in recruitment of white blood cells to the injured organs. These cells are part of the body's immune system that is important for fighting infection, however during organ injury they may promote further damage and scarring. We know that drugs that prevent recruitment of these immune cells to injured organs can slow, but not stop, progression of liver and kidney disease. However, some subsets of the immune cells may be beneficial as they are required for normal tissue functions and to promote repair. Hence, blocking all immune cells from reaching the damaged organ is not advisable and a more targeted approach to inhibit specifically those subsets that promote injury is likely to be more beneficial.In order to identify the specific immune cell subsets that promote organ injury, we have employed a state-of-the art technology called single-cell RNA sequencing in models of kidney and liver disease. This enabled us to determine which genes were switched on or off in individual immune cells. This revealed that there were many more immune cell subsets than we were previously aware of. By analysing the genes that are activated in each cell, we have identified a subset of immune cells that expresses many genes that promote inflammation and scarring, leading us to suspect that this subset may promote kidney and liver injury. The immune cells in this subset have a specific protein called CLEC4D on their surface and we believe that targeting this CLEC4D molecule may prevent organ injury in a more precise manner than current therapies.In this project we will use surplus tissue from biopsies from patients with liver and kidney disease to examine which molecular pathways are activated in the immune cells that express CLEC4D. This knowledge will help us develop new drugs that can prevent these cells causing inflammation and scarring. Our collaborators have developed an antibody that binds to and neutralises the action of CLEC4D. We will use pre-clinical models of kidney and liver injury to test whether this antibody prevents the activation of immune cells, thereby preventing development of scar tissue in the organs. If successful, this could be used to prevent the development of scarring in the organs of patients with kidney and liver disease.In addition, we have found a specific biochemical pathway is activated in the CLEC4D+ immune cells, which we believe contributes to inflammation and scarring. We will use genetic tools to block this pathway in the immune cells to test this hypothesis in models of kidney and liver disease. This will indicate whether blockade of this pathway by administration of a drug might be an alternative method of preventing kidney and liver scarring.In summary, our studies will determine whether a number of complementary strategies focused on inhibition of a specific subset of immune cells could reduce inflammation and scarring in organs including kidney and liver to prevent organ failure.