Disease Biophysics Group, Wyss Institute for Biologically Inspired Engineering, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, T. H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA.
Integr Biol (Camb). 2020 Apr 14;12(3):64-79. doi: 10.1093/intbio/zyaa005.
The blood-brain barrier plays a critical role in delivering oxygen and nutrients to the brain while preventing the transport of neurotoxins. Predicting the ability of potential therapeutics and neurotoxicants to modulate brain barrier function remains a challenge due to limited spatial resolution and geometric constraints offered by existing in vitro models. Using soft lithography to control the shape of microvascular tissues, we predicted blood-brain barrier permeability states based on structural changes in human brain endothelial cells. We quantified morphological differences in nuclear, junction, and cytoskeletal proteins that influence, or indicate, barrier permeability. We established a correlation between brain endothelial cell pair structure and permeability by treating cell pairs and tissues with known cytoskeleton-modulating agents, including a Rho activator, a Rho inhibitor, and a cyclic adenosine monophosphate analog. Using this approach, we found that high-permeability cell pairs showed nuclear elongation, loss of junction proteins, and increased actin stress fiber formation, which were indicative of increased contractility. We measured traction forces generated by high- and low-permeability pairs, finding that higher stress at the intercellular junction contributes to barrier leakiness. We further tested the applicability of this platform to predict modulations in brain endothelial permeability by exposing cell pairs to engineered nanomaterials, including gold, silver-silica, and cerium oxide nanoparticles, thereby uncovering new insights into the mechanism of nanoparticle-mediated barrier disruption. Overall, we confirm the utility of this platform to assess the multiscale impact of pharmacological agents or environmental toxicants on blood-brain barrier integrity.
血脑屏障在向大脑输送氧气和营养物质的同时，防止神经毒素的运输，起着至关重要的作用。由于现有的体外模型提供的空间分辨率和几何约束有限，预测潜在治疗剂和神经毒素调节血脑屏障功能的能力仍然是一个挑战。我们使用软光刻来控制微血管组织的形状，根据人脑内皮细胞的结构变化来预测血脑屏障的通透性状态。我们量化了影响或表明屏障通透性的核、连接和细胞骨架蛋白的形态差异。我们通过用已知的细胞骨架调节剂（包括 Rho 激活剂、Rho 抑制剂和环腺苷单磷酸类似物）处理细胞对和组织，建立了脑内皮细胞对结构和通透性之间的相关性。通过这种方法，我们发现高通透性细胞对表现出核伸长、连接蛋白丢失和肌动蛋白应力纤维形成增加，这表明收缩性增加。我们测量了高通透性和低通透性细胞对产生的牵引力，发现细胞间连接处的高应力有助于增加屏障通透性。我们进一步通过将细胞对暴露于工程纳米材料（包括金、银-硅和氧化铈纳米颗粒）来测试该平台预测脑内皮通透性变化的适用性，从而揭示了纳米颗粒介导的屏障破坏的机制的新见解。总的来说，我们证实了该平台在评估药物或环境毒物对血脑屏障完整性的多尺度影响方面的实用性。
