Lim Hyun Ju, Mosley Matthew C, Kurosu Yuki, Smith Callahan Laura A
The Vivian L. Smith Department of Neurosurgery, McGovern Medical School at The University of Texas Health Science Center at Houston, United States; Center for Stem Cell and Regenerative Medicine, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, United States.
The Vivian L. Smith Department of Neurosurgery, McGovern Medical School at The University of Texas Health Science Center at Houston, United States; Center for Stem Cell and Regenerative Medicine, Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, United States; The Department of Nanomedicine and Biomedical Engineering, University of Texas Health Science Center at Houston, United States; The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, United States.
Acta Biomater. 2017 Jul 1;56:153-160. doi: 10.1016/j.actbio.2016.11.063. Epub 2016 Dec 1.
N-cadherin cell-cell signaling plays a key role in the structure and function of the nervous system. However, few studies have incorporated bioactive signaling from n-cadherin into tissue engineering matrices. The present study uses a continuous gradient approach in polyethylene glycol dimethacrylate hydrogels to identify concentration dependent effects of n-cadherin peptide, His-Ala-Val-Asp-Lle (HAVDI), on murine embryonic stem cell survival and neural differentiation. The n-cadherin peptide was found to affect the expression of pluripotency marker, alkaline phosphatase, in murine embryonic stem cells cultured on n-cadherin peptide containing hydrogels in a concentration dependent manner. Increasing n-cadherin peptide concentrations in the hydrogels elicited a biphasic response in neurite extension length and mRNA expression of neural differentiation marker, neuron-specific class III β-tubulin, in murine embryonic stem cells cultured on the hydrogels. High concentrations of n-cadherin peptide in the hydrogels were found to increase the expression of apoptotic marker, caspase 3/7, in murine embryonic stem cells compared to that of murine embryonic stem cell cultures on hydrogels containing lower concentrations of n-cadherin peptide. Increasing the n-cadherin peptide concentration in the hydrogels facilitated greater survival of murine embryonic stem cells exposed to increasing oxidative stress caused by hydrogen peroxide exposure. The combinatorial approach presented in this work demonstrates concentration dependent effects of n-cadherin signaling on mouse embryonic stem cell behavior, underscoring the need for the greater use of systematic approaches in tissue engineering matrix design in order to understand and optimize bioactive signaling in the matrix for tissue formation.
Single cell encapsulation is common in tissue engineering matrices. This eliminates cellular access to cell-cell signaling. N-cadherin, a cell-cell signaling molecule, plays a vital role in the development of neural tissues, but has not been well studied as a bioactive signaling element in neural tissue engineering matrices. The present study uses a systematic continuous gradient approach to identify concentration dependent effects of n-cadherin derived peptide, HAVDI, on the survival and neural differentiation of murine embryonic stem cells. This work underscores the need for greater use to combinatorial strategies to understand the effect complex bioactive signaling, such as n-cadherin, and the need to optimize the concentration of such bioactive signaling within tissue engineering matrices for maximal cellular response.
N-钙黏蛋白细胞间信号传导在神经系统的结构和功能中起关键作用。然而，很少有研究将来自N-钙黏蛋白的生物活性信号整合到组织工程基质中。本研究在聚乙二醇二甲基丙烯酸酯水凝胶中采用连续梯度方法，以确定N-钙黏蛋白肽His-Ala-Val-Asp-Lle（HAVDI）对小鼠胚胎干细胞存活和神经分化的浓度依赖性影响。发现N-钙黏蛋白肽以浓度依赖性方式影响在含N-钙黏蛋白肽水凝胶上培养的小鼠胚胎干细胞中多能性标志物碱性磷酸酶的表达。水凝胶中N-钙黏蛋白肽浓度的增加在水凝胶上培养的小鼠胚胎干细胞中引发了神经突延伸长度和神经分化标志物神经元特异性III类β-微管蛋白mRNA表达的双相反应。与在含较低浓度N-钙黏蛋白肽水凝胶上培养的小鼠胚胎干细胞相比，发现水凝胶中高浓度的N-钙黏蛋白肽会增加小鼠胚胎干细胞中凋亡标志物半胱天冬酶3/7的表达。增加水凝胶中N-钙黏蛋白肽的浓度有助于提高暴露于过氧化氢引起的氧化应激增加的小鼠胚胎干细胞的存活率。本研究中提出的组合方法证明了N-钙黏蛋白信号对小鼠胚胎干细胞行为的浓度依赖性影响，强调了在组织工程基质设计中更多使用系统方法以理解和优化基质中生物活性信号以促进组织形成的必要性。
单细胞包封在组织工程基质中很常见。这消除了细胞对细胞间信号传导的接触。N-钙黏蛋白是一种细胞间信号分子，在神经组织发育中起重要作用，但作为神经组织工程基质中的生物活性信号元件尚未得到充分研究。本研究采用系统的连续梯度方法来确定N-钙黏蛋白衍生肽HAVDI对小鼠胚胎干细胞存活和神经分化的浓度依赖性影响。这项工作强调了更多使用组合策略来理解复杂生物活性信号（如N-钙黏蛋白）的作用以及在组织工程基质中优化此类生物活性信号浓度以实现最大细胞反应的必要性。
