In Utero Programming of Adult Vascular Function

不利的胎儿环境与成人疾病之间的关联可能会被特定疾病（如血管疾病）的遗传易感性所混淆，因为传递给胎儿的母体基因也可能设置子宫环境。流行病学研究可能无法区分不利的子宫环境与母亲和胎儿共同的遗传易感性。内皮型一氧化氮合酶（endothelial nitric oxide synthase, NOS3）在决定成人血管功能中起重要作用，其功能缺乏会导致妊娠期血管适应异常和不利的胎儿环境，我们将缺乏功能性NOS3基因的转基因小鼠（NOS3-/- ko）与其野生型对照（NOS3+/+WT）进行杂交，以阐明胎儿环境与遗传在决定成人血管功能中的作用。我们的初步结果表明，从父亲那里继承功能性NOS3等位基因并因此在NOS3-/- ko母亲（NOS3+Pat/- mat）中发育的杂合成体的血管表型与NOS3-/- ko小鼠相似。相比之下，在NOS3+/+WT母鼠（NOS3+Mat/-Pat）中发育的继承父亲无功能NOS3等位基因的杂合成虫的血管表型与NOS3+/+WT小鼠相似。我们假设，观察到的杂合小鼠之间的差异是由于NOS3-/- ko妊娠中NOS3功能缺失导致血管适应改变，导致子宫环境不利，从而导致胎儿编程。为了验证这一假设，我们提出了以下目标：1)测定NOS3-/- ko雌性与NOS3-/- ko或NOS3+/+WT雄性交配所生的成年后代的血管功能和血压，并将其与NOS3+/+WT雌性与NOS3-/- ko或NOS3+/+WT雄性交配所生的后代进行比较；2)通过比较NOS3-+Pat/-Mat、NOS3+Mat/-Pat、NOS3-/- ko和NOS3+/+WT胚胎移植至NOS3-/- ko代孕母亲与NOS3+/+WT代孕母亲的后期血管表型，确定子宫环境与遗传的作用；3)通过检查妊娠期间NOS3+Pat/-Mat、NOS3+Mat/-Pat、NOS3-/- ko和NOS3+/+WT的血管表型（目的3a），以及它们成年后后代的血管表型（目的3b），确定胎儿编程的跨代后果；4)比较NOS3+Pat/-Mat、NOS3+Mat/-Pat、NOS3-/- ko和NOS3+/+WT在同一母鼠第1、2、5次妊娠中所生后代的成年血管表型：该模型与子宫环境异常相关的不良妊娠结局，如子痫前期和胎儿生长受限有关，对后代的长期健康具有重要意义。

The reported association between an unfavorable fetal environment and adult diseases may be confounded by a genetic predisposition toward specific diseases (eg, vascular diseases) as the maternal genes that are transmitted o the fetus may also set the uterine environment. Epidemiological studies may not differentiate between the unfavorable uterine environment vs the hereditary predisposition common to mother and fetus. As endothelial nitric oxide synthase (NOS3) is important in determining vascular function in adults, and deficiency in its function leads to abnormal vascular adaptations in pregnancy and an unfavorable fetal environment, we crossbred transgenic mice lacking a functional NOS3 gene (NOS3-/-KO) and their wild-type control (NOS3+/+WT) to clarify the roles of the fetal environment vs genetics in determining adult vascular function. Our preliminary results show that the vascular phenotype in heterozygous adult that inherit the functional NOS3 allele from the father and therefore develop in NOS3-/-KO mothers (NOS3+Pat/-Mat) is similar to NOS3-/-KO mice. In contrast, the vascular phenotype in heterozygous adults that inherit the father's nonfunctional NOS3 allele and develop in NOS3+/+WT mothers (NOS3+Mat/-Pat) is similar to NOS3+/+WT mice. We hypothesize that the observed difference between the heterozygous mice is due to fetal programming caused by an unfavorable uterine environment resulting from altered vascular adaptations in the NOS3-/-KO pregnancy secondary to lack of NOS3 function. To test this hypothesis, we propose the following aims: 1) determine vascular function and blood pressure in adult offspring born to NOS3-/-KO females bred with NOS3-/-KO or NOS3+/+WT males, and compare them to offspring of NOS3+/+WT females bred with NOS3-/-KO or NOS3+/+WT males; 2) determine the roles of uterine environment vs genetics by comparing the vascular phenotype in later life in NOS3-+Pat/-Mat, NOS3+Mat/-Pat, NOS3-/-KO and NOS3+/+WT embryos transferred into NOS3-/-KO surrogate mothers to those transferred into NOS3+/+WT surrogate mothers; 3) determine the transgenerational consequences of fetal programming by examining the vascular phenotype in NOS3+Pat/-Mat, NOS3+Mat/-Pat, NOS3-/-KO and NOS3+/+WT during pregnancy (aim 3a), as well as in their offspring in adult life (aim 3b); 4) compare adult vascular phenotype between NOS3+Pat/-Mat , NOS3+Mat/-Pat, NOS3-/-KO and NOS3+/+WT offspring born to the same dams in the 1st, 2nd, and 5th pregnancies: This unique model is relevant to adverse pregnancy outcomes related to abnormal uterine environment, such as preeclampsia and fetal growth restriction, and has significant implications regarding the long-term health of offspring.