Multimodal Optical Imaging on the Effect of Maternal Polysubstance Exposure on Fetal Brain Microvessel Function

项目摘要 先天性脑发育异常的病因是复杂的，但产前酒精/乙醇和尼古丁暴露 (PEE/PNE）是美国和全球常见的致病因素。研究主要集中在增长 PEE/PNE后神经干细胞（NSC）及其后代的缺陷。不过，我们最近使用了高- 分辨率成像，以证明PEE导致主要颅侧血流的互补性缺陷， 定向动脉在上一个项目期间，我们采用了光学相干断层扫描（OCT）， 文献表明PEE和PNE均导致传出神经周围血管中类似的血流损失 神经丛（PNVP）。PNVP和它的同伴脑室下血管丛（SVP）产生毛细血管 穿透发育中大脑的实质在胎儿心室区（VZ）的NSC龛中， 产生一类非典型的有孔毛细血管，其包含50-100 nm大小的跨内皮窗口。 胎儿脑内毛细血管开窗的功能尚不清楚。尽管如此，在成年人的大脑中， 在选定的脑室周围脑区的有孔毛细血管促进全身性 大分子进入大脑，大脑小胶质细胞的持续激活，以及残留的神经原性小生境， 促进神经发生。根据初步和已发表的数据，我们假设产前乙醇将 增加脑血管生成、毛细血管开窗和小胶质细胞免疫细胞前体向胎儿的运输 个脑袋我们进一步假设，产前尼古丁将加强酒精介导的增加新的血液 血管形成的胎儿大脑和附加增加毛细血管通透性和免疫细胞迁移到 胎儿VZ的NSC龛。为了验证这些假设，我们的团队将开发一种新的灵敏的，高分辨率的 结合OCT和双光子光片互补优势的成像平台（Aim 1） 显微镜（2 pLSM）用于胎儿脑毛细血管微血管的宫内时间分辨结构成像， 分子特异性我们还将调整我们创新的活体成像技术和小鼠报告模型 评估PEE和/或PNE对胎儿VZ毛细血管动态生长的影响， 将大分子从胎儿体循环转移到大脑（目的2）， 免疫小胶质细胞前体进入胎儿NSC小生境（Aim 3）。 该提案将产生用于子宫内胎儿成像的创新性高分辨率成像工具，并使 第一次，动态，时间分辨评估毛细血管通透性和单核细胞前体侵入，以填补 我们对PEE和/或PNE引起的脑生长缺陷的起源的理解存在重大差距。这些 研究也将使我们开始评估新的药物干预策略的有效性 有针对性地预防或逆转PEE和PNE对胎儿的影响

PROJECT SUMMARY The etiology of congenital brain growth anomalies is complex, but prenatal alcohol/ethanol and nicotine exposure (PEE/PNE) are common causal factors in the US and worldwide. Research has mainly focused on the growth deficits in neural stem cells (NSCs) and their progeny following PEE/PNE. However, we recently used high- resolution imaging to document that PEE results in complementary deficits in blood flow in major cranially- directed arteries. During the previous project period, we adapted Optical Coherence Tomography (OCT) to document that both PEE and PNE resulted in a similar loss of blood flow in the efferent peri-neural vascular plexus (PNVP). The PNVP and its companion, the sub-ventricular vascular plexus (SVP), give rise to capillaries that penetrate the parenchyma of the developing brain. In the NSC niche of the fetal ventricular zone (VZ) these give rise to an atypical class of fenestrated capillaries that contain 50-100 nm-sized trans-endothelial windows. The function of capillary fenestration in the fetal brain is unknown. Still, in the adult brain, the presence of fenestrated capillaries in selected circumventricular brain regions facilitates the transfer of systemic macromolecules into the brain, and persistent activation of brain microglia, and in residual neurogenic niches, facilitates neurogenesis. Based on preliminary and published data, we hypothesize that prenatal ethanol will increase brain angiogenesis, capillary fenestration, and microglial immune cell precursor trafficking to the fetal brain. We further hypothesize that prenatal nicotine will potentiate the alcohol-mediated increase in new blood vessel formation in the fetal brain and additively increase capillary permeability and immune cell migration into the NSC niche of the fetal VZ. To test these hypotheses, our team will develop a new sensitive, high-resolution imaging platform (Aim 1) that combines the complementary benefits of OCT and two-photon light-sheet microscopy (2pLSM) for in utero time-resolved structural imaging of fetal brain capillary micro-vessels with molecular specificity. We will also adapt our innovative intravital imaging technology and mouse reporter models to assess the effects of PEE and/or PNE on the dynamic growth of fetal VZ capillaries and their capacity to transfer macromolecules from fetal systemic circulation to the brain (Aim 2) and the adhesion and diapedesis of immune microglial cell precursors into the fetal NSC niche (Aim 3). This proposal will result in innovative high-resolution imaging tools for in utero fetal imaging and enable for the first time, dynamic, time-resolved assessment of capillary permeability and monocyte precursor invasion, to fill a significant gap in our understanding of the genesis of brain growth deficits due to PEE and/or PNE. These studies will also position us to begin to assess the efficacy of novel pharmacological intervention strategies targeted to prevent or reverse the effects of PEE and PNE on fetuses