Modulation of Signal Transduction by Nano-Topography

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。我们以前和正在进行的工作集中在定义天然基底膜的地形和确定生物学相关的长度尺度对调节角膜上皮细胞行为的“表型影响”。使用硅表面图案的凹槽和脊，我们已经表明，生物长度尺度的地形特征调节角膜上皮细胞的方向，粘附，迁移和增殖。拓扑结构也影响粘着斑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，在许多行为的细胞反应地形的过渡发生在约。1，200 nm间距（间距=脊+槽宽度），其中形貌的最大影响通常发生在纳米级范围内，即在天然基底膜中发现的特征尺寸范围。观察到的效应可能是直接引起的（例如，在细胞膜处引发的生物力学转导事件）和/或间接引起的（例如，基质的形貌决定粘附复合物的密度和/或分布，粘附复合物进而调节细胞行为）。初步数据支持中心假设，即基质的纳米级（1-100 nm）和亚微米（< 1 μ m）地形特征（在天然角膜基底膜中发现的特征）限制了局部接触结构，导致信号传导和细胞反应改变。这些研究与我们对地形线索在角膜上皮正常发育和维持中所起作用的基本理解相关。此外，所产生的数据将有助于组织工程的新策略的产生，并促进眼假体的发展。我们已经组建了一个强大的跨学科团队的高级研究人员来测试以下假设：假设1：整合素和syndecans介导的地形线索的细胞反应。假设2：地形特征的尺度调节GTP酶Ras超家族的活性。假设3：地形特征的尺度调节基质受体激酶靶点，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.