Thorpe Abbey A, Binch Abbie L A, Creemers Laura B, Sammon Christopher, Le Maitre Christine L
Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK.
UMC Utrecht, Orthopaedics Department, Utrecht, Netherlands.
Oncotarget. 2016 Jan 19;7(3):2189-200. doi: 10.18632/oncotarget.6782.
Progress in mesenchymal stem cell (MSC) based therapies for nucleus pulposus (NP) regeneration are hampered by a lack of understanding and consensus of the normal NP cell phenotype. Despite the recent consensus paper on NP markers, there is still a need to further validate proposed markers. This study aimed to determine whether an NP phenotypic profile could be identified within a large population of mature NP samples.qRT-PCR was conducted to assess mRNA expression of 13 genes within human non-degenerate articular chondrocytes (AC) (n=10) and NP cells extracted from patients across a spectrum of histological degeneration grades (n=71). qRT-PCR results were used to select NP marker candidates for protein expression analysis.Differential expression at mRNA between AC and non-degenerate NP cells was only observed for Paired Box Protein 1 (PAX1) and Forkhead box F1 (FOXF1). In contrast no other previously suggested markers displayed differential expression between non-degenerate NP and AC at mRNA level. PAX1 and FOXF1 protein expression was significantly higher in the NP compared to annulus fibrosus (AF), cartilaginous endplate (CEP) and AC. In contrast Laminin-5 (LAM-332), Keratin-19 (KRT-19) and Hypoxia Inducible Factor 1 alpha (HIF1α) showed no differential expression in NP cells compared with AC cells.A marker which exclusively differentiates NP cells from AF and AC cells remains to be identified, raising the question: is the NP a heterogeneous population of cells? Or does the natural biological variation during IVD development, degeneration state and even the life cycle of cells make finding one definitive marker impossible?
基于间充质干细胞（MSC）的椎间盘髓核（NP）再生疗法的进展因对正常NP细胞表型缺乏理解和共识而受阻。尽管最近有关于NP标志物的共识文件，但仍需要进一步验证所提出的标志物。本研究旨在确定是否能在大量成熟NP样本中识别出NP表型特征。进行qRT-PCR以评估10例人非退变关节软骨细胞（AC）和71例从不同组织学退变等级患者中提取的NP细胞中13个基因的mRNA表达。qRT-PCR结果用于选择NP标志物候选物进行蛋白质表达分析。仅在配对盒蛋白1（PAX1）和叉头框F1（FOXF1）方面观察到AC和非退变NP细胞之间mRNA的差异表达。相比之下，之前提出的其他标志物在非退变NP和AC之间的mRNA水平上未显示差异表达。与纤维环（AF）、软骨终板（CEP）和AC相比，NP中PAX1和FOXF1蛋白表达显著更高。相比之下，层粘连蛋白-5（LAM-332）、角蛋白-19（KRT-19）和缺氧诱导因子1α（HIF1α）在NP细胞与AC细胞中未显示差异表达。一种能将NP细胞与AF和AC细胞完全区分开的标志物仍有待确定，这就引发了一个问题：NP是细胞的异质群体吗？还是椎间盘退变发展过程中、退变状态甚至细胞生命周期中的自然生物学变异使得找到一个确定的标志物成为不可能？
