Effect of diabetes on myelopoiesis and atherosclerosis

描述(申请人提供)：糖尿病患者心血管并发症的发生率较高，如心肌梗死和中风。糖尿病患者最常见的死因是冠状动脉疾病，这是动脉粥样硬化的并发症。然而，动脉粥样硬化在糖尿病患者中高度流行的原因尚不清楚。在糖尿病小鼠中，我们发现骨髓中髓系细胞和髓系祖细胞的水平显著升高。在最近的一项研究中，我们描述了心肌梗死后造血干细胞和造血祖细胞的激活增加了髓系细胞的产生，导致动脉粥样硬化加速。基于这些观察，我们假设糖尿病诱导偏髓系造血干细胞(HSCs)，增加骨髓生成，最终由于增加单核细胞对斑块的供应而导致动脉粥样硬化加重。我们将在三个具体目标上验证这一假说：1.我们将调查糖尿病是否会诱导骨髓生成，特别是脾和骨髓等造血器官中的单核细胞生成。我们还将调查糖尿病是否会使单核细胞更具侵袭性。我们将用链脲佐菌素诱导C57BL/6小鼠糖尿病(1型糖尿病模型)。肥胖的自发性瘦素突变纯合子小鼠(lepob/ob；通常被称为ob/ob小鼠)将被用作2型糖尿病的模型。2.我们将研究糖尿病是否会使HSC向髓系细胞分化。我们将计数骨髓和脾中的HSCs，并研究从糖尿病小鼠分离的HSCs是否具有容易分化为髓系祖细胞的倾向。为了测试HSC向髓系定向分化的机制，我们将研究白细胞介素3受体(IL-3R)信号的作用。 3.我们将用siRNA敲除负责单核细胞祖细胞维持和分化的巨噬细胞集落刺激因子受体(MCSF-R)。我们将研究MCSF-R基因敲除是否减少了糖尿病诱导的骨髓生成，从而改善了动脉粥样硬化。这项研究的长期目标是确定糖尿病患者干细胞和祖细胞水平的变化，并开发治疗方法来减少糖尿病患者的心血管并发症。为了促进我从一个有指导的博士后奖学金到一个稳定的独立研究职位的过渡，K99阶段将作为综合的职业发展和研究活动进行，R00阶段将致力于执行拟议的研究，建立合作关系，并撰写R01补助金。

DESCRIPTION (provided by applicant): Patients with diabetes mellitus have a higher incidence of cardiovascular complications, such as myocardial infarction and stroke. Diabetic patient's most common cause of death is coronary artery disease, which is a complication of atherosclerosis. However, it is not well understood why atherosclerosis is highly prevalent in diabetic patients. In diabetic mice, we found significantly higher levels of myeloid cells and myeloid cell progenitors in the bone marrow. In a recent study, we described that hematopoietic stem and progenitor cell activation after myocardial infarction increases production of myeloid cells, leading to accelerated atherosclerosis. Based on these observations, we hypothesize that diabetes induces myeloid-biased hematopoietic stem cells (HSCs), increases myelopoiesis, and finally results in exacerbated atherosclerosis due to higher supply of monocytes to plaque. We will test this hypothesis in 3 specific aims: 1.We will investigate if diabetes induces myelopoiesis, particularly monocytopoiesis in hematopoietic organs like the spleen and bone marrow. We will also investigate if diabetes makes monocytes more aggressive. We will use streptozotocin to induce diabetes in C57BL/6 mice (model for type 1 diabetes). Mice homozygous for the obese spontaneous leptin mutation (Lepob/ob; commonly referred to as ob/ob mice) will be used as a model for type 2 diabetes. 2.We will investigate if diabetes biases differentiation of HSCs towards myeloid lineages. We will enumerate HSCs in the bone marrow and spleen, and investigate if HSCs isolated from diabetic mice have a propensity to readily differentiate into myeloid progenitors. To test the mechanism of preferential HSC differentiation towards myeloid lineages, we will investigate the role of interleukin-3 receptor (IL-3R) signaling. 3. We will knock down the receptor for macrophage colony stimulating factor (MCSF-R), responsible for maintenance and differentiation of monocyte progenitors, with an siRNA. We will investigate if MCSF-R knockdown reduces diabetes-induced myelopoiesis, resulting in amelioration of atherosclerosis. The long-term goal of the study is to identify changes at stem and progenitor cell levels in diabetes and develop therapeutic approaches to reduce cardiovascular complications in diabetic patients. To facilitate my transition from a mentored postdoctoral fellowship to a stable independent research position, the K99 phase will be conducted as integrated mentored career development and research activities, and the R00 phase will be devoted to execution of the proposed research, establishing collaborations, and writing an R01 grant.