Effect of shear stress on coronary smooth muscle maturation

项目摘要 这项建议的主要目标是了解为什么发育中的冠状动脉 在特定的位置形成的。在冠状动脉的发育过程中，许多未成熟的冠状动脉 线束连接到主动脉，然后重塑形成成人心脏中观察到的两条成熟的动脉。 在这一重建过程中，最大的变化之一应用于新连接的冠状动脉 血管系统是突然出现的流体剪应力，但流体剪应力对血管的调节作用 冠状动脉血管系统的发展完全未知。这项提案特别提到了如何 血流的启动会引起切应力，从而诱导促进平滑肌的信号通路 迁移、增殖和成熟。目标1检查大动脉周围的环境 早期的平滑肌重新聚集到冠脉。据预测，低水平的剪应力将 促进ET1的表达，从而导致基质金属蛋白酶(MMP)的活性，从而产生一个环境 这促进了平滑肌肉的迁移。该目标将评估ET1、MMP2和MMP9的表达以及 鸡胚胎发育中冠状动脉的平滑肌增殖。MMP2卵内注射 而9种抑制剂将证实这些MMPs对平滑肌迁移的必要性。Aim 2考察了 剪切力水平增加对细胞信号转导的影响，特别是转录因子KLF2和 一氧化氮合酶eNOS。高水平的剪应力被预测为诱发KLF2并导致eNOS 磷酸化，促进平滑肌成熟。因此，不对称的剪应力会选择性地 成熟的平滑肌肉，解释了冠状动脉的一致图案。内皮型一氧化氮合酶的卵子抑制作用 活动将确认eNOS活性是否是平滑肌成熟和冠状动脉所必需的 稳定性。大多数建议的技术对本科生来说都很容易掌握，并且 初步数据是由本科生生成的，支持该项目的可行性 波特兰大学。总而言之，这一提议位于物理力量、分子力量和 反应和细胞行为，最终目的是了解冠状动脉的形成。 动脉。通过更好地了解这些动脉的正常发育，拟议的研究将支持 未来的工作是研究这些发育过程是如何出错的，从而导致危及生命的先天性 冠状动脉异常。

Project Summary The broad objective of this proposal is to understand why the developing coronary arteries are consistently formed at specific locations. During development of the coronary arteries, numerous immature coronary strands connect to the aorta and then remodel to form the two mature arteries observed in the adult heart. During this remodeling process, one of the biggest changes applied to the newly connected coronary vasculature is the sudden onset of fluid shear stress, yet the regulatory role of fluid shear stress on the development of the coronary vasculature is completely unknown. This proposal specifically addresses how the onset of blood flow, which causes shear stress, induces signaling pathways that would promote smooth muscle migration, proliferation, and maturation. Aim 1 examines the environment surrounding the aorta during the early stages of smooth muscle recruitment to the coronaries. Low levels of shear stress are predicted to promote expression of ET1 and thus lead to matrix metalloprotease (MMP) activity, yielding an environment that promotes smooth muscle migration. This aim will evaluate ET1, MMP2, and MMP9 expression as well as smooth muscle proliferation in the developing coronary arteries of the chick embryo. In ovo injection of MMP2 and 9 inhibitors will confirm the necessity of these MMPs for smooth muscle migration. Aim 2 examines the effects of increased levels of shear stress on cell signaling, particularly the transcription factor KLF2 and the nitric oxide synthase eNOS. High levels of shear stress are predicted to induce KLF2 and lead to eNOS phosphorylation, which promote smooth muscle maturation. Asymmetrical shear stress would thus selectively mature smooth muscle, explaining the consistent patterning of the coronary arteries. In ovo inhibition of eNOS activity will confirm whether eNOS activity is required for smooth muscle maturation and coronary artery stability. Most of the proposed techniques are easily accessible to undergraduate research students, and the preliminary data were generated by undergraduate students, supporting the feasibility of this project at the University of Portland. Altogether, this proposal sits at the intersection among physical forces, molecular responses, and cellular behavior, with the end objective of understanding the formation of the coronary arteries. By better understanding the normal development of these arteries, the proposed research will support future work to examine how these developmental processes go awry, leading to life-threatening congenital coronary artery anomalies.