Tppp3~+synovial/tendon sheath progenitor cells contribute to heterotopic bone after trauma

Heterotopic ossification(HO)is a pathological process resulting in aberrant bone formation and often involves synovial lined tissues.During this process,mesenchymal progenitor cells undergo endochondral ossification.Nonetheless,the specific cell phenotypes and mechanisms driving this process are not well understood,in part due to the high degree of heterogeneity of the progenitor cells involved.Here,using a combination of lineage tracing and single-cell RNA sequencing(sc RNA-seq),we investigated the extent to which synovial/tendon sheath progenitor cells contribute to heterotopic bone formation.For this purpose,Tppp3(tubulin polymerization-promoting protein family member 3)-inducible reporter mice were used in combination with either Scx(Scleraxis)or Pdgfra(platelet derived growth factor receptor alpha)reporter mice.Both tendon injury-and arthroplasty-induced mouse experimental HO models were utilized.Sc RNA-seq of tendon-associated traumatic HO suggested that Tppp3 is an early progenitor cell marker for either tendon or osteochondral cells.Upon HO induction,Tppp3 reporter^(+)cells expanded in number and partially contributed to cartilage and bone formation in either tendon-or joint-associated HO.In double reporter animals,both Pdgfra^(+)Tppp3^(+)and Pdgfra^(+)Tppp3^(-) progenitor cells gave rise to HO-associated cartilage.Finally,analysis of human samples showed a substantial population of TPPP3^(-) expressing cells overlapping with osteogenic markers in areas of heterotopic bone.Overall,these data demonstrate that synovial/tendon sheath progenitor cells undergo aberrant osteochondral differentiation and contribute to HO after trauma.

PDGFRαreporter activity identifies periosteal progenitor cells critical for bone formation and fracture repair

The outer coverings of the skeleton,which is also known as the periosteum,are arranged in concentric layers and act as a reservoir for tissue-specific bone progenitors.The cellular heterogeneity within this tissue depot is being increasingly recognized.Here,inducible PDGFRαreporter animals were found to mark a population of cells within the periosteum that act as a stem cell reservoir for periosteal appositional bone formation and fracture repair.During these processes,PDGFRαreporter^(+)progenitors give rise to Nestin+periosteal cells before becoming osteoblasts and osteocytes.The diphtheria toxin-mediated ablation of PDGFRαreporter^(+)cells led to deficits in cortical bone formation during homeostasis and a diminutive hard callus during fracture repair.After ossicle transplantation,both mouse PDGFRαreporter^(+)periosteal cells and human Pdgfrα+periosteal progenitors expand,ossify,and recruit marrow to a greater extent than their counterpart periosteal cells,whereas PDGFRαreporter^(−)periosteal cells exhibit a predisposition to chondrogenesis in vitro.Total RNA sequencing identified enrichment of the secreted factors Fermt3 and Ptpn6 within PDGFRαreporter^(+)periosteal cells,which partly underlie the osteoblastogenic features of this cell population.

人血浆作为真皮支架对自体皮肤增殖的影响:组织学和免疫组织化学试验(英文)

背景:组织工程是一个多学科研究的交叉学科,其目标是使人体损伤的组织和器官再生,通过这种假设,几乎所有的动物组织都可以在实验室进行培养。一般的方法是从需要移植的患者身上提取干细胞,在一定的支持条件下允许其生长、增殖、生产为可替换的组织。另一方面,寻找细胞能够互相联结并形成分层结构的合适的支持条件,如基质或支架等非常必要。目前用于烧烫伤治疗的材料有很多种,如胶原,透明质酸、纤维蛋白和聚乳酸及其共聚物。目的:讨论以新型的生物材料自体血浆为支架对自体成纤维细胞和角质化细胞生长、扩张、增殖的影响。设计:建立一种真皮再生的方法,将自体成纤维细胞浸于人血浆基质中,排除各种影响样本安全性和排斥反应的问题,应用同样的方法在新的真皮上获取角质化细胞。时间及地点:实验于 2008 年在意大利曼多瓦 C. Poma 医院动物工厂完成。材料:人角质化细胞和成纤维细胞取自 1 例58 岁乳房切除患者的皮肤碎片。实验得到C. Poma 医院独立伦理委员会批准,患者知情同意。方法:从自体活组织皮肤样本中分离人角质化细胞和成纤维细胞,置于培养瓶中增殖,随后将自体血浆作为皮肤移植形成构造的支架,免疫和免疫组织化学特征显示与正常皮肤相似。主要观察指标:将血浆样本用甲醛固定,埋入石蜡,苏木精-伊红染色,用显微镜进行细胞计数。所有样本均经免疫组织化学评估。结果:在血浆基质上获得了多层规则形状的角质化细胞和成纤维细胞,基底膜的形成说明自体血浆是角质化细胞和成纤维细胞的生长、分化、扩展的良好支架,真皮和表皮细胞联结重建皮肤移植与正常皮肤无异。结论:血浆作为角质化细胞和成纤维细胞分化、扩展的支架表现出良好的性能,同时实验还特别发现成纤维细胞浓缩血浆可以暂时替代皮肤,也是角质化细胞生长的强有力的支架。此外血浆还具有廉价,易于制备等优点。自体角质化细胞和成纤维细胞及自体血浆的应用,可以避免血种类型的免疫排斥反应。这种治疗方法给有慢性缺损并且需要连续移植的患者带来了希望。