Incorporation of Endothelial Progenitor Cells into Placental Vaculature

描述（由申请人提供）：成功的胎盘发育对成人健康具有长期影响，是胚胎存活和胎儿正常生长所必需的，并依赖于血管形成。在妊娠期间，胎盘血管伸长、扩张并延伸新芽，以促进营养物质从母体血管最大限度地转移到胎盘血管，从而为发育中的胚胎/胎儿提供造血支持。长期的研究目标是识别和确定促进胎盘内血管生长的生理途径。内皮祖细胞（EPCs）存在于骨髓中，迁移并结合到生长的血管中以形成新的内皮细胞。EPCs与肺动脉高压、心血管风险、局部缺血、动脉粥样硬化和妊娠之间的关系已经确定。先兆子痫和妊娠期糖尿病患者EPC数量减少，糖尿病妊娠期间母体胰岛素治疗可增加EPC数量。我们从新生猪的外周血中分离并鉴定了EPCs。这些EPCs表达整合素，并使用这些跨膜受体在体外粘附和迁移到骨桥蛋白（OPN）上，骨桥蛋白是一种在人和猪胎盘中均有显著表达的细胞外基质分子。当EPCs作为单层单独培养在补充有血管生成因子的3D胶原基质表面时，它们不能侵入基质。然而，如果与侵入基质并形成血管结构的成人脐静脉内皮细胞（HUVECs）一起培养，则EPCs并入这些血管结构中。这与它们在体内的行为相似。重要的是，OPN剂量依赖性地增加并入这些血管结构的EPC的数量。中心假设是OPN将EPCs募集到胎盘内的新血管形成部位。一旦到达那里，EPC通过连接粘附分子（即，间隙、紧密连接和粘附连接）结合到生长的血管中。这两个目标是：（1）确定允许EPCs并入建立的脉管系统的细胞间信号;和（2）确定EPCs是否并入猪的胎盘血管网络。这些目标的实现将有助于合理设计和开发基于静脉内EPC的新型治疗方法，以使胎盘血管正常化，并减轻先兆子痫、妊娠期糖尿病和其他妊娠期疾病的影响。

DESCRIPTION (provided by applicant): Successful placental development has long-term implications for adult health, is necessary for embryo survival and proper fetal growth, and is dependent on vascularization. During pregnancy, placental blood vessels elongate, dilate, and extend new sprouts to facilitate maximal transfer of nutrients from maternal to placental vasculatures for hematotrophic support of the developing embryo/fetus. The long-term research goal is to identify and determine the physiological pathways that promote vessel growth within the placenta. Endothelial Progenitor Cells (EPCs) reside in the bone marrow, migrate, and incorporate into growing blood vessels to form new endothelial cells. A firm relationship has been established between EPCs and pulmonary hypertension, cardiovascular risk, ischemia, atherosclerosis, and pregnancy. EPC numbers decrease in preeclampsia and gestational diabetes, and maternal insulin therapy increases EPC numbers during diabetic pregnancy. We have isolated and characterized EPCs from the peripheral blood of newborn pigs. These EPCs express integrins, and use these transmembrane receptors to adhere and migrate in vitro on osteopontin (OPN) an extracellular matrix molecule with prominent expression in the placenta of both humans and pigs. When EPCs are cultured alone as a monolayer on the surface of 3D collagen matrices supplemented with angiogenic factors, they fail to invade the matrix. However, if cultured with adult human umbilical vein endothelial cells (HUVECs), which invade the matrix and form vascular structures, the EPCs incorporate into these vascular structures. This is similar to their behavior in vivo. Importantly, OPN dose-dependently increases the number of EPCs that incorporate into these vascular structures. The central hypothesis is that OPN recruits EPCs to sites of neovascularization within the placenta. Once there, EPCs communicate directly with adult endothelial cells via junctional adhesion molecules (i.e., gap, tight and adherens junctions) to incorporate into growing vessels. The two objectives are: (1) Determine the intercellular signals that allow EPCs to incorporate into established vasculature; and (2) Determine whether EPCs incorporate into placental vascular networks pigs. Completion of these objectives will aid the rational design and development of novel intravenous EPC-based therapies to normalize placental vasculature, and lessen effects of preeclampsia, gestational diabetes, and other gestational diseases.