Abstract：
Mouse models are invaluable to understanding fundamental mechanisms in vascular biology during development, in health and different disease states. Several constitutive or inducible models that selectively knockout or knock in genes in vascular endothelial cells exist; however, functional and phenotypic differences exist between microvascular and macrovascular endothelial cells in different organs. In order to study microvascular endothelial cell-specific biological processes, we developed a Tamoxifen-inducible von Willebrand Factor (vWF) Cre recombinase mouse in the SJL background. The transgene consists of the human vWF promoter with the microvascular endothelial cell-selective 734 base pair sequence to drive Cre recombinase fused to a mutant estrogen ligand-binding domain [ERT2] that requires Tamoxifen for activity (CreERT2) followed by a polyadenylation (polyA) signal. We initially observed Tamoxifen-inducible restricted bone marrow megakaryocyte and sciatic nerve microvascular endothelial cell Cre recombinase expression in offspring of a mixed strain hemizygous C57BL/6-SJL founder mouse bred with mT/mG mice, with >90% bone marrow megakaryocyte expression efficiency. Founder mouse offspring were backcrossed to the SJL background by speed congenics, and intercrossed for >10 generations to develop hemizygous Tamoxifen-inducible vWF Cre recombinase (vWF-iCre/+) SJL mice with stable transgene insertion in chromosome 1. Microvascular endothelial cell-specific Cre recombinase expression occurred in the sciatic nerves, brains, spleens, kidneys and gastrocnemius muscles of adult vWF-iCre/+ SJL mice bred with Ai14 mice, with retained low level bone marrow and splenic megakaryocyte expression. This novel mouse strain would support hypothesis-driven mechanistic studies to decipher the role(s) of specific genes transcribed by microvascular endothelial cells during development, as well as in physiologic and pathophysiologic states in an organ- and time-dependent manner.
摘要：
小鼠模型对于理解发育过程中血管生物学的基本机制是非常宝贵的，在健康和不同的疾病状态。存在几种选择性敲除或敲入血管内皮细胞基因的组成型或诱导型模型；然而，不同器官的微血管和大血管内皮细胞之间存在功能和表型差异。为了研究微血管内皮细胞特异性生物学过程，我们在SJL背景下开发了他莫昔芬诱导型血管性血友病因子(vWF)Cre重组酶小鼠。转基因由人vWF启动子和微血管内皮细胞选择性734碱基对序列组成，以驱动Cre重组酶，该Cre重组酶融合到需要他莫昔芬活性（CreERT2）的突变雌激素配体结合域[ERT2]，然后是聚腺苷酸化（polyA）信号。我们最初观察到他莫昔芬诱导的限制性骨髓巨核细胞和坐骨神经微血管内皮细胞Cre重组酶在混合品系半合子C57BL/6-SJL创始人小鼠与mT/mG小鼠饲养的后代中的表达，具有>90%的骨髓巨核细胞表达效率。创始人老鼠的后代通过速度基因回交到SJL背景，并杂交>10代以开发半合子他莫昔芬诱导型vWFCre重组酶（vWF-iCre/）SJL小鼠，在1号染色体上具有稳定的转基因插入。微血管内皮细胞特异性Cre重组酶表达发生在坐骨神经，大脑,脾脏,用Ai14小鼠饲养的成年vWF-iCre/SJL小鼠的肾脏和腓肠肌，保留低水平的骨髓和脾巨核细胞表达。这种新型小鼠品系将支持假设驱动的机制研究，以破译由微血管内皮细胞转录的特定基因在发育过程中的作用。以及生理和病理生理状态以器官和时间依赖性的方式。
