Modulation of Signal Transduction by Nano-Topography

描述：细胞生物学中的一个基本问题是表面形貌如何调节细胞行为。我们之前和正在进行的工作主要集中在定义天然基底膜的形貌，并确定生物相关长度尺度对调节角膜上皮细胞行为的“表型影响”。使用带有凹槽和脊纹的硅表面，我们已经证明了生物长度尺度的地形特征调节角膜上皮细胞的取向、黏附、迁移和增殖。地形还影响局灶性粘连的结构和方向，以及细胞内细胞骨架元素的分布和方向。重要的是，我们已经证明，对于许多行为，细胞对地形的反应大约发生在。1,200 nm的节距(节距=脊+槽宽度)与地形的最大影响通常发生在纳米级范围内，这是在天然基底膜中发现的特征尺寸的范围。观察到的效应可能是直接引起的(例如，在细胞膜上启动的生物力学转导事件)和/或间接引起的(例如，基质的形貌决定了黏附复合体的密度和/或分布，而黏附复合体反过来调节细胞行为)。初步数据支持这一中心假设，即基质的纳米级(1-100 nm)和亚微米(1微米)的地形特征，即天然角膜基底膜的特征，限制了焦点接触结构，导致信号和细胞反应的改变。这些研究有助于我们从根本上理解地形图提示在角膜上皮的正常发育和维持中所起的作用。此外，所产生的数据将有助于组织工程中新策略的形成，并推动眼球假体的发展。我们已经组建了一个由高级研究人员组成的强大的跨学科团队来测试以下假设：假设1：整合素和合成素介导细胞对地形提示的反应。假设2：地形特征的大小调节Ras超家族GTP酶的活性。假设3：地形特征的大小调节基质受体激酶靶标，进而调节细胞行为。

DESCRIPTION: A fundamental question in cell biology is how surface topography regulates cell behavior. Our previous and ongoing work has focused on defining the topography of native basement membranes and determining the "phenotypic impact" of biologically relevant length scales on modulating corneal epithelial cell behaviors. Using silicon surfaces patterned with grooves and ridges, we have shown that biologic length scale topographic features modulate corneal epithelial cell orientation, adhesion, migration and proliferation. Topography also influences the architecture and orientation of focal adhesions as well as the distribution and orientation of cytoskeletal elements within the cell. Importantly, we have demonstrated that a transition in the cellular response to topography for many behaviors occurs at approx. 1,200 nm pitch (pitch = ridge + groove width) with the greatest impact of topography generally occurring in the nanoscale range, the range of feature sizes found in the native basement membrane. It is possible that the observed effects are caused directly (e.g. biomechanical transduction events initiated at the cell membrane) and/or indirectly (e.g. the topography of the substratum dictates the density and/or distribution of adhesion complexes which in turn modulate cell behaviors). Preliminary data support the central hypothesis that nanoscale (1-100 nm) and submicron (< 1 mu m) topographic features of the substratum, characteristic of those found in the native corneal basement membranes, constrain focal contact architecture resulting in altered signaling and cellular responses. These studies have relevance to our fundamental understanding of the role that topographic cues play in the normal development and maintenance of the corneal epithelium. Furthermore, data generated will contribute to the genesis of novel strategies in tissue engineering and advance the development of ocular prosthetics. We have assembled a strong interdisciplinary team of senior investigators to test the following hypotheses: Hypothesis 1: Integrins and syndecans mediate cellular responses to topographic cues. Hypothesis 2: The scale of topographic features modulates the activity of the Ras superfamily of GTPases. Hypothesis 3: The scale of topographic features modulates matrix receptor kinase targets that, in turn, modulate cell behaviors.