Wilson Christina L, Hayward Stephen L, Kidambi Srivatsan
Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, 820 N 16 Street, 207 Othmer Hall, NE, 68588, USA.
Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, 855 N 16 St, Lincoln, NE, 68588, USA.
RSC Adv. 2016;6(41):34447-34457. doi: 10.1039/C5RA25916A. Epub 2016 Mar 17.
Astrogliosis due to brain injury or disease can lead to varying molecular and morphological changes in astrocytes. Magnetic resonance elastography and ultrasound have demonstrated that brain stiffness varies with age and disease state. However, there is a lack in understanding the role of varied stiffness on the progression of astrogliosis highlighting a critical need to engineer models that mimic disease stages. Such models need to incorporate the dynamic changes in the brain microenvironment including the stiffness changes. In this study we developed a polydimethyl siloxane (PDMS) based platform that modeled the physiologically relevant stiffness of brain in both a healthy (200 Pa) and diseased (8000 Pa) state to investigate the effect of stiffness on astrocyte function. We observed that astrocytes grown on soft substrates displayed a consistently more quiescent phenotype while those on stiff substrates displayed an astrogliosis-like morphology. In addition to morphological changes, astrocytes cultured on stiff substrates demonstrated significant increase in other astrogliosis hallmarks - cellular proliferation and glial fibrillary acidic protein (GFAP) protein expression. Furthermore, culturing astrocytes on a stiff surface resulted in increased reactive oxygen species (ROS) production, increased super oxide dismutase activity and decreased glutamate uptake. Our platform lends itself for study of potential therapeutic strategies for brain injury focusing on the intricate brain microenvironment-astrocytes signaling pathways.
脑损伤或疾病引起的星形胶质细胞增生可导致星形胶质细胞发生不同的分子和形态变化。磁共振弹性成像和超声显示，脑硬度随年龄和疾病状态而变化。然而，目前尚缺乏对不同硬度在星形胶质细胞增生进展中作用的了解，这突出表明迫切需要构建模拟疾病阶段的模型。此类模型需要纳入脑微环境的动态变化，包括硬度变化。在本研究中，我们开发了一种基于聚二甲基硅氧烷（PDMS）的平台，该平台模拟了健康（200 Pa）和患病（8000 Pa）状态下脑的生理相关硬度，以研究硬度对星形胶质细胞功能的影响。我们观察到，在软基质上生长的星形胶质细胞表现出始终更静止的表型，而在硬基质上生长的星形胶质细胞则表现出星形胶质细胞增生样形态。除形态变化外，在硬基质上培养的星形胶质细胞在其他星形胶质细胞增生标志方面也有显著增加——细胞增殖和胶质纤维酸性蛋白（GFAP）蛋白表达。此外，在硬表面培养星形胶质细胞会导致活性氧（ROS）产生增加、超氧化物歧化酶活性增加以及谷氨酸摄取减少。我们的平台有助于研究针对脑损伤的潜在治疗策略，重点关注复杂的脑微环境 - 星形胶质细胞信号通路。
