Roles of Hsp20-Exosomes in Myocardial Angiogenesis

Hsp20-外泌体在心肌血管生成中的作用

• 批准号: 8577869
• 负责人: Guo-Chang Fan
• 金额: $ 37.72万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-18 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8577869
• 关键词: Address; Adult; Angiogenic Factor; Animal Model; Animals; Attenuated; Biogenesis; Blood Vessels; Blood capillaries; Bone Marrow; Cardiac; Cardiac Myocytes; Cell Proliferation; Cells; Coronary Arteriosclerosis; Data; Development; Diabetes Mellitus; Disease; Endothelial Cells; Exhibits; FGF2 gene; Funding; Generations; Goals; Growth Factor; Heart; Human; In Vitro; Injection of therapeutic agent; Knockout Mice; Knowledge; Lead; Life; Mediating; Mesenchymal Stem Cells; Mission; Modeling; Molecular Chaperones; Morbidity - disease rate; Mus; Muscle Cells; Myocardial; Operative Surgical Procedures; Patients; Play; Production; Proteins; Public Health; Rattus; Regulation; Research; Role; Signal Pathway; Small Interfering RNA; Source; Stem cells; Streptozocin; Stress; Testing; Therapeutic; Transgenic Mice; Translating; Translational Research; Tube; United States; Vascular Endothelial Growth Factor Receptor-2; Vascular Endothelial Growth Factors; Work; angiogenesis; attenuation; base; capillary; density; diabetic; diabetic patient; diabetic rat; disability; improved; insight; intercellular communication; interest; migration; mortality; mouse model; nanovesicle; novel; novel therapeutics; overexpression; paracrine; public health relevance; research study; therapeutic angiogenesis; tool; translational study; treatment strategy

DESCRIPTION (provided by applicant): Currently, therapeutic angiogenesis via direct delivery of growth factors has shown great promise in animal models, but has not been successful in humans thus far. Therefore, continuing search for effective therapeutic approaches aimed at promoting myocardial angiogenesis is desperately needed. Our recent work interestingly showed that Hsp20-overexpressing cardiomyocytes (Hsp20-myocytes) possessed pro- angiogenic capacity, which was associated with increased secretion of exosomes, a group of naturally occurring nano-vesicles (30-100nm) actively released from cells. In addition, our latest data showed that: 1) exosomes derived from Hsp20-myocytes, but not from Hsp20-knockdown myocytes, contained a large amount of Hsp20, VEGFR2 and p-Akt, which were efficiently transferred into endothelial cells, resulting in activation of the pro-angiogenic signaling pathway; 2) Hsp20 interacted with Tsg101, a protein known to be involved in exosome biogenesis; and 3) knockdown of Tsg101 by siRNA attenuated exosome secretion from Hsp20-myocytes. Thus, it will be very important to test whether exosome quantity (Tsg101-dependent exosome biogenesis) or quality (Hsp20-reprogrammed exosomes) is critical for Hsp20-myocyte-elicited pro- angiogenesis. We hypothesize that exosomes and Hsp20 are both required for cardiomyocyte-catalyzed angiogenesis, and that Hsp20-reprogrammed exosomes have therapeutic benefits to diabetic animal hearts, which exhibit an impaired post-ischemic angiogenesis and microvascular rarefaction. These hypotheses will be tested by pursuing three specific aims: 1) Determine whether exosomes are essential for Hsp20- myocyte-induced angiogenesis. Currently, we are generating a mouse model with cardiac-specific deletion of Tsg101 to inhibit exosome production. This model will be crossed with Hsp20-transgenic mice for testing whether Hsp20-myocyte-elicited pro-angiogenic effects are attenuated by blockade of exosome generation. 2) Determine whether Hsp20 is required for exosome-mediated myocardial angiogenesis. We are creating an inducible mouse model with cardiac-specific deletion of Hsp20 to test whether Hsp20 plays an essential role in reprogramming pro-angiogenic exosomes. 3) Test whether Hsp20-stem cell- derived exosomes improve angiogenesis in diabetic animal hearts. We propose to use bone marrow- derived mesenchymal stem cells as a therapeutic source of Hsp20-reprogrammed exosomes, because they are more readily obtained than cardiomyocytes. We will use streptozotocin (STZ)-induced diabetic rats and the Goto-Kakizaki (GK) rats, two well-established diabetic animal models, to pursue this translational research. Together, the proposed studies are expected to unveil a previously unrecognized role of Hsp20 in exosomal reprogramming and in the promotion of cardiomyocyte-induced angiogenesis. Additionally, it is expected to provide novel insights that lead to the development of original exosome-based therapeutic strategies for the treatment of coronary artery disease.

描述（由申请人提供）：目前，通过直接递送生长因子的治疗性血管生成在动物模型中显示出巨大的前景，但迄今为止在人类中尚未取得成功。因此，迫切需要继续寻找旨在促进心肌血管生成的有效治疗方法。我们最近的工作有趣地表明，Hsp20 过度表达的心肌细胞（Hsp20 肌细胞）具有促血管生成能力，这与外泌体的分泌增加有关，外泌体是一组从细胞中主动释放的天然存在的纳米囊泡（30-100nm）。此外，我们的最新数据表明：1）源自Hsp20肌细胞而非Hsp20敲低肌细胞的外泌体含有大量Hsp20、VEGFR2和p-Akt，它们被有效转移到内皮细胞中，导致促血管生成信号通路的激活； 2) Hsp20 与 Tsg101 相互作用，Tsg101 是一种已知参与外泌体生物合成的蛋白质； 3) siRNA 敲低 Tsg101 可减弱 Hsp20 肌细胞的外泌体分泌。因此，测试外泌体数量（Tsg101依赖性外泌体生物发生）或质量（Hsp20重编程外泌体）对于Hsp20肌细胞引发的促血管生成是否至关重要是非常重要的。我们假设外泌体和 Hsp20 都是心肌细胞催化的血管生成所必需的，并且 Hsp20 重编程的外泌体对糖尿病动物心脏具有治疗作用，糖尿病动物心脏表现出缺血后血管生成受损和微血管稀疏。这些假设将通过追求三个具体目标来检验：1）确定外泌体是否对于 Hsp20 肌细胞诱导的血管生成至关重要。目前，我们正在构建一种心脏特异性删除 Tsg101 的小鼠模型，以抑制外泌体的产生。该模型将与 Hsp20 转基因小鼠杂交，以测试 Hsp20 肌细胞引发的促血管生成作用是否会因外泌体生成的阻断而减弱。 2)确定Hsp20是否是外泌体介导的心肌血管生成所必需的。我们正在创建一种心脏特异性缺失 Hsp20 的诱导型小鼠模型，以测试 Hsp20 是否在促血管生成外泌体重编程中发挥重要作用。 3) 测试Hsp20干细胞衍生的外泌体是否改善糖尿病动物心脏的血管生成。我们建议使用骨髓间充质干细胞作为 Hsp20 重编程外泌体的治疗来源，因为它们比心肌细胞更容易获得。我们将使用链脲佐菌素 (STZ) 诱导的糖尿病大鼠和 Goto-Kakizaki (GK) 大鼠这两种成熟的糖尿病动物模型来开展这项转化研究。总之，拟议的研究预计将揭示 Hsp20 在外泌体重编程和促进心肌细胞诱导的血管生成中先前未被认识的作用。此外，预计它将提供新的见解，从而导致开发基于外泌体的原创治疗冠状动脉疾病的治疗策略。