Induction of allogeneic tolerance with bioengineered thymus organoids

用生物工程胸腺类器官诱导同种异体耐受

• 批准号: 9082794
• 负责人: YONG FAN
• 金额: $ 38.36万
• 依托单位: ALLEGHENY-SINGER RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-15 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9082794
• 关键词: 3-Dimensional; Address; Adult; Adverse effects; Aging; Alloantigen; Allogenic; Antigens; Autoantigens; Autoimmune Diabetes; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Beta Cell; Biomedical Engineering; Cell Culture Techniques; Cell Lineage; Cell Transplants; Cells; Chronic; Data; Development; Diabetic mouse; Disease; Embryo; Extracellular Matrix; Genetic; Goals; Graft Rejection; Growth; Homing; Human; Hydrogels; Immune; Immune Tolerance; Immune system; Immunization; Immunosuppressive Agents; In Vitro; Individual; Infection; Insulin; Insulin-Dependent Diabetes Mellitus; Invaded; Investigation; Lymphocyte; Lymphopoiesis; Major Histocompatibility Complex; Malignant Neoplasms; Modeling; Modification; Molecular; Nude Mice; Organ; Organ Donor; Organ Transplantation; Organoids; Ovalbumin; Peptides; Pharmaceutical Preparations; Pharmacotherapy; Population; Population Heterogeneity; Prevention; Property; Regenerative Medicine; Research; Research Project Grants; Self Tolerance; Signal Pathway; Skin graft; Solid; Source; Stem cells; Stromal Cells; Structure of beta Cell of islet; System; T-Cell Development; T-Lymphocyte; Techniques; Technology; Thymic epithelial cell; Thymus Gland; Translating; Transplantation; Vascularization; adaptive immunity; allograft rejection; autoreactive T cell; base; central tolerance; clinical application; design; driving force; improved; in vivo; innovation; irradiation; islet; islet allograft; pathogen; postnatal; prevent; progenitor; public health relevance; research study; response; scaffold; skin allograft; transplantation medicine

 DESCRIPTION: Chronic rejection of allografts remains a major hurdle in organ transplantation and regenerative medicine. While immunosuppressive drugs can prevent graft rejection to a certain degree, their efficacies are limited and often associate with severe side effects. The underlying problem is that new T-cells reactive to alloantigens are continuously generated from the thymus. While numerous efforts have been made to modulate thymic function to induce donor-specific immune tolerance, manipulating the thymus proves to be difficult. One major challenge is to reproduce its unique extracellular matrix microenvironment that is critical for the survival and function of thymic epithelial cells (TECs), the predominant population of thymic stromal cells that are essential for the development of T-cells and for defining the "immunological self" of an individual (the capability to distinguish self from non-self molecules i the body and respond accordingly). Here, we propose an innovative bioengineering approach to modulate the thymus function. We have recently developed a thymus decellularization technique, which allows us to reconstruct a functional thymus organoid de novo with isolated TECs. Athymic mice engrafted with the bioengineered thymus are able to develop strong humoral responses against model antigen ovalbumin and promptly reject skin allografts. Conversely, tolerance to allogeneic skin grafts can be achieved by transplanting thymus organoids co-expressing both donor and recipient's major histocompatibility complex (MHC) molecules. Based on these observations, we hypothesize that the bioengineered thymus organoid can recapitulate the function of a thymus in vivo, and are able to redefine the "immunological self" of the adaptive immune system. Given that the major translational experimental focus in our group is on Type 1 diabetes (T1D), in which the insulin-secreting beta cells of the pancreas becomes targets of autoimmune destruction due to loss of self-tolerance, we will focus our investigation on whether the bioengineered thymus organoids can re-establish immune tolerance to beta-cells. Furthermore, we will investigate whether we can simultaneously induce donor-specific immune tolerance to islet allografts with the thymus bioengineering technology. Experiments in Aim 1 will optimize the construction of the thymus organoids from decellularized thymic scaffolds in vitro. Our focus in Aim 2 is to optimize the long-term survival and function of the bioengineered thymus organoids in vivo. Experiments in Aim 3 is to demonstrate that the bioengineered thymus constructed with insulin- expressing allogeneic TECs can effectively modulate the adaptive immune system to reverse insulin-autoimmunity, one of the primary driving forces for T1D progression, and to establish immune tolerance of islet allografts. The long-term goal of the research project is to translate the thymus bioengineering technique into clinical applications.

 描述：同种异体移植物的慢性排斥仍然是器官移植和再生医学的主要障碍。虽然免疫抑制药物可以在一定程度上预防移植排斥，但其疗效有限，并且常常伴有严重的副作用。根本问题是胸腺不断产生对同种抗原有反应的新 T 细胞。尽管已经做出了大量努力来调节胸腺功能以诱导供体特异性免疫耐受，但事实证明操纵胸腺是困难的。一项主要挑战是重现其独特的细胞外基质微环境，这对于 胸腺上皮细胞 (TEC) 是胸腺基质细胞的主要群体，对于 T 细胞的发育和定义个体的“免疫自我”（区分自身与体内非自身分子并做出相应反应的能力）至关重要。在这里，我们提出了一种创新的生物工程方法来调节胸腺功能。我们最近开发了一种胸腺脱细胞技术，使我们能够用分离的 TEC 从头重建功能性胸腺类器官。植入生物工程胸腺的无胸腺小鼠能够针对模型抗原卵清蛋白产生强烈的体液反应，并迅速排斥皮肤同种异体移植物。相反，对同种异体皮肤移植的耐受性可以通过移植共表达供体和受体的主要组织相容性复合体（MHC）分子的胸腺类器官来实现。基于这些观察，我们假设生物工程胸腺类器官可以重现体内胸腺的功能，并且能够重新定义适应性免疫系统的“免疫学自我”。鉴于我们小组的主要转化实验重点是 1 型糖尿病 (T1D)，其中胰腺分泌胰岛素的 β 细胞由于自我耐受性的丧失而成为自身免疫破坏的目标，因此我们将重点研究生物工程胸腺类器官是否可以重建对 β 细胞的免疫耐受。此外，我们将研究是否可以利用胸腺生物工程技术同时诱导对同种异体胰岛移植物的供体特异性免疫耐受。目标 1 中的实验将优化体外脱细胞胸腺支架的胸腺类器官的构建。我们目标 2 的重点是优化生物工程胸腺类器官在体内的长期存活和功能。目标3的实验是证明用表达胰岛素的同种异体TEC构建的生物工程胸腺可以有效调节适应性免疫系统以逆转胰岛素自身免疫（T1D进展的主要驱动力之一），并建立同种异体胰岛移植物的免疫耐受。该研究项目的长期目标是将胸腺生物工程技术转化为临床应用。