Effect of diabetes on myelopoiesis and atherosclerosis

描述（申请人提供）：糖尿病患者心肌梗死、脑卒中等心血管并发症发生率较高。糖尿病患者最常见的死亡原因是冠状动脉疾病，这是动脉粥样硬化的并发症。然而，为什么动脉粥样硬化在糖尿病患者中非常普遍还不是很清楚。在糖尿病小鼠中，我们发现骨髓中髓系细胞和髓系细胞祖细胞的水平明显升高。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祖细胞的激活增加了髓样细胞的产生，导致动脉粥样硬化加速。基于这些观察结果，我们假设糖尿病诱导骨髓偏向性造血干细胞（hsc），增加骨髓生成，并最终导致单核细胞向斑块供应增加而加剧动脉粥样硬化。我们将在三个具体目标中检验这一假设：1。我们将研究糖尿病是否诱导骨髓生成，特别是造血器官如脾脏和骨髓的单核细胞生成。我们还将研究糖尿病是否使单核细胞更具攻击性。我们将使用链脲佐菌素诱导C57BL/6小鼠（1型糖尿病模型）糖尿病。肥胖自发性瘦素突变纯合小鼠（Lepob/ob；通常称为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造血干细胞向髓系分化。我们将枚举骨髓和脾脏中的造血干细胞，并研究从糖尿病小鼠中分离的造血干细胞是否有容易分化为骨髓祖细胞的倾向。为了测试HSC向髓系分化的优先机制，我们将研究白细胞介素-3受体（IL-3R）信号传导的作用。

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.