Bridgen Devin T, Fearing Bailey V, Jing Liufang, Sanchez-Adams Johannah, Cohan Megan C, Guilak Farshid, Chen Jun, Setton Lori A
Department of Biomedical Engineering, Duke University, United States.
Department of Biomedical Engineering, Washington University in St. Louis, United States.
Acta Biomater. 2017 Jun;55:100-108. doi: 10.1016/j.actbio.2017.04.019. Epub 2017 Apr 20.
Nucleus pulposus (NP) cells are derived from the notochord and differ from neighboring cells of the intervertebral disc in phenotypic marker expression and morphology. Adult human NP cells lose this phenotype and morphology with age in a pattern that contributes to progressive disc degeneration and pathology. Select laminin-mimetic peptide ligands and substrate stiffnesses were examined for their ability to regulate human NP cell phenotype and biosynthesis through the expression of NP-specific markers aggrecan, N-cadherin, collagen types I and II, and GLUT1. Peptide-conjugated substrates demonstrated an ability to promote expression of healthy NP-specific markers, as well as increased biosynthetic activity. We show an ability to re-express markers of the juvenile NP cell and morphology through control of peptide presentation and stiffness on well-characterized polyacrylamide substrates. NP cells cultured on surfaces conjugated with α3 integrin receptor peptides P4 and P678, and on α2, α5, α6, β1 integrin-recognizing peptide AG10, show increased expression of aggrecan, N-cadherin, and types I and II collagen, suggesting a healthier, more juvenile-like phenotype. Multi-cell cluster formation was also observed to be more prominent on peptide-conjugated substrates. These findings indicate a critical role for cell-matrix interactions with specific ECM-mimetic peptides in supporting and maintaining a healthy NP cell phenotype and bioactivity.
NP cells reside in a laminin-rich environment that deteriorates with age, including a loss of water content and changes in the extracellular matrix (ECM) structure that may lead to the development of a degenerated IVD. There is great interest in methods to re-express healthy, biosynthetically active NP cells using laminin-derived biomimetic peptides toward the goal of using autologous cell sources for tissue regeneration. Here, we describe a novel study utilizing several laminin mimetic peptides conjugated to polyacrylamide gels that are able to support an immature, healthy NP phenotype after culture on "soft" peptide gels. These findings can support future studies in tissue regeneration where cells may be directed to a desired regenerative phenotype using niche-specific ECM peptides.
髓核（NP）细胞起源于脊索，在表型标志物表达和形态上与椎间盘的相邻细胞不同。随着年龄增长，成年人类NP细胞会丧失这种表型和形态，这种模式会导致椎间盘进行性退变和病变。研究了选择的层粘连蛋白模拟肽配体和底物硬度通过NP特异性标志物聚集蛋白聚糖、N-钙黏蛋白、I型和II型胶原蛋白以及葡萄糖转运蛋白1（GLUT1）的表达来调节人类NP细胞表型和生物合成的能力。肽偶联底物表现出促进健康NP特异性标志物表达以及增加生物合成活性的能力。我们展示了通过控制在特征明确的聚丙烯酰胺底物上的肽呈现和硬度来重新表达幼年NP细胞标志物和形态的能力。在与α3整合素受体肽P4和P678偶联的表面以及与α2、α5、α6、β1整合素识别肽AG10偶联的表面上培养的NP细胞，聚集蛋白聚糖、N-钙黏蛋白以及I型和II型胶原蛋白的表达增加，表明呈现出更健康、更类似幼年的表型。在肽偶联底物上还观察到多细胞簇形成更为显著。这些发现表明细胞与基质与特定细胞外基质模拟肽的相互作用在支持和维持健康NP细胞表型及生物活性方面起着关键作用。
NP细胞存在于富含层粘连蛋白的环境中，该环境会随着年龄增长而恶化，包括水分含量丧失和细胞外基质（ECM）结构变化，这可能导致退变椎间盘的形成。人们对使用层粘连蛋白衍生的仿生肽重新表达健康、具有生物合成活性的NP细胞的方法非常感兴趣，目的是利用自体细胞来源进行组织再生。在此，我们描述了一项新颖的研究，该研究利用几种与聚丙烯酰胺凝胶偶联的层粘连蛋白模拟肽，在“软”肽凝胶上培养后能够支持未成熟、健康的NP表型。这些发现可为未来组织再生研究提供支持，在这些研究中，可利用特定生态位的ECM肽将细胞引导至所需的再生表型。
