Can valvular interstitial cells become true osteoblasts? A side-by-side comparison.
Can valvular interstitial cells become true osteoblasts? A side-by-side comparison.
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发表时间：
2011-07
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通讯作者：
E. Monzack;K. Masters
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作者：
E. Monzack;K. Masters
研究背景和目的 主动脉瓣钙化被认为涉及瓣膜间质细胞（VIC）分化为肌纤维母细胞或成骨细胞样表型。尽管据称患病 VIC 和成骨细胞之间存在相似性，但很少有研究在并行实验中直接比较 VIC 和成骨细胞。在本研究中，VIC 与不同分化阶段的多种成骨细胞类型进行了比较。这些发现可能有助于解决 VIC 在达到成骨细胞样阶段之前是否会经历肌纤维母细胞表型的问题。方法 代表一系列成骨细胞谱系定型和分化的三种细胞类型用于与 VIC 进行表型比较。具体来说，VIC、胚胎成纤维细胞 (C3H10T1/2)、前成骨细胞 (MC3T3-E1) 和成熟的原代成骨细胞在对照或矿化培养基中的组织培养聚苯乙烯上培养，并在 1 至 8 天的时间点收获用于 qPCR、DNA 和蛋白质分析。结果 在矿化培养基中培养 VIC 降低了 α-平滑肌肌动蛋白（α-SMA；一种肌成纤维细胞标记物）的表达，且矿化培养基中的 α-SMA 基因或蛋白表达在任何时间点都没有出现峰值。矿化培养基的应用导致所有细胞类型的碱性磷酸酶（ALP；一种早期矿化标记物）表达水平增加，尽管 VIC 中 ALP 增加的幅度远小于成骨细胞类型。只有成骨细胞类型表现出骨钙素（后期矿化的指标）明显增加。结论 虽然添加矿化介质通常会增加成骨标志物的表达并减少肌纤维母细胞标志物的表达，但 VIC 与用于比较的成骨细胞类型相比，表现出不同的表达水平和模式。此外，在向 VIC 添加矿化介质后的任何时刻，α-SMA 均未增加，表明这些细胞在达到成骨细胞样基因表达谱之前可能不需要经历肌成纤维细胞阶段。
BACKGROUND AND AIM OF THE STUDY Aortic valve calcification is believed to involve the differentiation of valvular interstitial cells (VICs) into either a myofibroblastic or an osteoblast-like phenotype. Despite purported similarities between diseased VICs and osteoblasts, few studies have directly compared VICs and osteoblasts in side-by-side experiments. In the present study, VICs were compared against multiple osteoblastic cell types at different stages of differentiation. These findings may help to resolve whether VICs progress through a myofibroblastic phenotype before reaching an osteoblast-like stage. METHODS Three cell types representing a range of osteoblastic lineage commitment and differentiation were used in the phenotypic comparison against VICs. Specifically, VICs, embryonic fibroblasts (C3H10T1/2), pre-osteoblasts (MC3T3-E1), and mature primary osteoblasts were cultured on tissue-culture polystyrene in control or mineralization medium, and harvested for qPCR, DNA, and protein analysis at time points ranging from one to eight days. RESULTS Culture of VICs in mineralization medium decreased the expression of alpha-smooth muscle actin (alpha-SMA; a myofibroblast marker), with no peak in alpha-SMA gene or protein expression in mineralization medium at any time point. The application of a mineralization medium led to increased expression levels of alkaline phosphatase (ALP; an early mineralization marker) for all cell types, although the magnitude of the increase in ALP was drastically smaller for VICs than for the osteogenic cell types. Only the osteogenic cell types demonstrated an appreciable increase in osteocalcin (an indicator of later-stage mineralization). CONCLUSION While the addition of mineralization medium generally increased the expression of osteogenic markers and decreased the expression of myofibroblastic markers, VICs displayed different levels and patterns of expression than the osteoblastic cell types used for comparison. Additionally, the lack of an alpha-SMA increase at any point after the addition of mineralization medium to VICs indicated that these cells may not need to progress through a myofibroblastic stage before reaching an osteoblast-like gene expression profile.