Exogenous and Endogenous Stem Cells for Skeletal Regeneration.
Exogenous and Endogenous Stem Cells for Skeletal Regeneration.
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用于骨骼再生的外源和内源干细胞。
DOI：
10.1155/2018/2574243
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发表时间：
2018
影响因子：
4.3
通讯作者：
Yang,Liu
中科院分区：
文献类型：
--
作者：
Zhu,Heng;Yu,Bo;Yang,Liu
在过去的几十年里，干细胞在骨骼重建中的优化应用越来越受到人们的关注。通常，外源性多能细胞来源于脂肪组织、骨和软骨等多种结缔组织，在适当的细胞培养体系中体外扩增，然后静脉输送到体内或注射到骨骼组织中。这些外源干细胞有望到达组织利基，分化为专门的骨骼细胞，并保护骨骼组织免受有害刺激。然而，外源干细胞的再生机制以及体外扩增对干细胞生物学特性的潜在影响仍然很大程度上是未知的，这限制了干细胞在骨再生方面的临床应用。根据外源性干细胞在骨骼重建中的治疗作用，目前已知内源性干细胞参与了骨骼修复。在体外和体内的刺激下，这些组织特异性干细胞增殖，迁移到专门的组织利基，并分化以重建骨骼结构和功能。此外，内源性干细胞的精确再生机制还不完全清楚。因此，更多地了解外源性干细胞和内源性干细胞的再生效果及其潜在的机制将有助于指导我们改进基于干细胞的骨骼重建。在本期特刊中，我们首先对W.Du等人进行了全面的回顾。成纤维细胞生长因子在牙齿发育和门牙更新中的作用。他们认为，牙齿组织的形成以及持续生长的小鼠切牙中干细胞的发育和动态平衡，是由多个成纤维细胞生长因子家族成员介导的。他们讨论了成纤维细胞生长因子信号在这些矿化组织中的作用，试图区分其不同的功能，并强调了成纤维细胞生长因子和其他信号通路之间的串扰。此外，由L.Huang等人撰写的一篇原创文章进一步证实了成纤维细胞生长因子家族成员在骨骼再生中的关键作用。他们发现，成纤维细胞生长因子-18对人脂肪间充质干细胞(ADSC)的软骨分化和基质沉积有积极影响。更重要的是，FGF18和转化生长因子β3在体外颗粒模型中对ADSCs的软骨形成有协同作用。近年来，除FGFs外，血小板衍生生长因子(PDGF)作为一种促进组织修复的因子被广泛应用于骨重建。然而，PDGF调控干细胞基骨再生的机制在很大程度上仍不清楚。张明等人。结果表明，PDGF-BB促进间充质干细胞成骨分化，但抑制其成脂分化。此外，分泌的PDGF-BB显著促进人脐静脉内皮细胞迁移和血管生成。最重要的是，通过使用临界大小的大鼠颅骨缺损模型，他们表明PDGF-BB过表达显著改善了MSC介导的血管生成和活体成骨。干细胞的干性是分化干细胞的显著特征之一，它控制着种子细胞库的大小和种子细胞对骨骼再生的多能性。在张顺生等人的一项原创研究中。在本期特刊中，
The optimized applications of stem cells for skeletal reconstruction have been gaining more and more attention in the past decades. Generally, the exogenous multipotent cells are obtained from numerous connective tissues including adipose tissues, bones, and cartilages; expanded in an appropriate cell culture system in vitro; and intravenously delivered into the bodies or injected into skeletal tissues. These exogenous stem cells are expected to arrive in the tissue niches, differentiate into specialized skeletal cells, and protect the skeletal tissues from harmful stimuli. However, the underlying mechanisms of the regenerative effects of exogenous stem cells and the potential influences of the in vitro expansion on the stem cell biological characteristics remained largely elusive, which have confined the clinical applications of stem cells for skeletal regeneration. In accordance with the therapeutic effects of exogenous stem cells in skeletal reconstruction, endogenous stem cells are known now to be involved in skeletal repair. Upon the in vitro and in vivo stimuli, these tissue-specific stem cells proliferate, migrate to the specialized tissue niches, and differentiate to reconstruct the skeletal structure and function. Also, the precise regenerative mechanisms of endogenous stem cells are incompletely understood. Therefore, more details of the regenerative effects of both exogenous stem cells and endogenous stem cells, and their underlying mechanisms would be helpful to guide us in improving stem cell-based skeletal reconstruction. In this special issue, we first present a thorough review by W. Du et al. on the role of fibroblast growth factors in tooth development and incisor renewal. They suggest that the formation of dental tissues, as well as the development and homeostasis of the stem cells in the continuously growing mouse incisor, is mediated by multiple FGF family members. They discuss the role of FGF signaling in these mineralized tissues, trying to separate its different functions and highlighting the crosstalk between FGFs and other signaling pathways. In addition, the pivotal roles of the FGF family member in skeletal regeneration are further validated by an original article authored by L. Huang et al. They found that FGF-18 had a positive impact on chondrogenic differentiation and matrix deposition of human adipose-derived mesenchymal stem cells (ADSC). More importantly, synergistic effects of FGF-18 and TGF-β3 were observed on the chondrogenesis of the ADSCs in vitro pellet model. Besides FGFs, platelet-derived growth factor (PDGF), a promoting factor for tissue repair, has been widely used in bone reconstruction in recent years. However, the mechanism by which PDGF regulates stem cell-based bone regeneration still remained largely unelucidated. M. Zhang et al. demonstrated that PDGF-BB increased osteogenic differentiation but inhibited adipogenic differentiation of mesenchymal stem cells (MSCs). In addition, secreted PDGF-BB significantly enhanced human umbilical vein endothelial cell migration and angiogenesis. Most importantly, they showed that PDGF-BB overexpression significantly improved MSC-mediated angiogenesis and osteogenesisin vivoby using a critical-sized rat calvarial defect model. Stemness is one of the distinct features of stem cells from differentiated cells, which control the size of seed cell pool and the multipotency of seed cells for skeletal regeneration. In an original study from S. Zhang et al. in the current special issue,