Abstract 161: identification of cell-intrinsic mechanisms and differentially regulated genetic pathways responsible for the age-related functional decline in aged skeletal stem cells.
Abstract 161: identification of cell-intrinsic mechanisms and differentially regulated genetic pathways responsible for the age-related functional decline in aged skeletal stem cells.
复制标题
摘要 161：鉴定导致衰老骨骼干细胞与年龄相关的功能衰退的细胞内在机制和差异调节的遗传途径。
DOI：
10.1097/01.prs.0000444990.75431.f1
复制
发表时间：
2014
影响因子：
3.6
通讯作者：
Longaker,MichaelT
中科院分区：
文献类型：
--
作者：
McArdle,Adrian;Chan,Charles;Seita,Jun;Senarath-Yapa,Kshemendra;Hu,Michael;Walmsley,GrahamG;Zielins,Elizabeth;Atashroo,David;Tevlin,Ruth;Weissman,Irving;Longaker,MichaelT
目的：衰老与维持成年组织结构和功能的稳态机制的逐渐丧失有关。大多数成体组织含有常驻干细胞，它们在整个生物体的生命周期中增殖以补偿组织损失。人们认为，成体干细胞的时间衰老和复制衰老都会对其组织再生功能产生负面影响。自然衰老对骨骼愈合有深远的影响，随着年龄的增长，愈合能力下降，骨质疏松症的发生率增加。在小鼠中，我们已经在骨骼组织中发现了一个常驻干细胞库。我们可以在克隆水平上成功地分离出高度纯化的骨骼干细胞群体，这些干细胞具有形成骨、软骨、基质和功能骨髓腔的能力。本研究探讨了细胞内在机制，以及外源性干细胞生态位在影响骨骼干细胞衰老中的作用。这项研究的目的是确定可能被操纵的潜在途径，以逆转骨骼干细胞衰老的影响。方法：使用一组新的细胞表面标记物，通过荧光激活细胞分选（FACS）前瞻性地分离高度纯化的骨骼干细胞群体。进行微阵列分析以确定随衰老而差异调节的遗传途径。采用肾包膜下的等慢性和异慢性移植来检测细胞内在功能，以评估它们在异位位置的成骨能力。为了确定老化的骨骼暴露在年轻、健康的循环中是否会改善骨骼健康，我们通过手术配对小鼠，创造等慢性和异慢性异种共生，以确定是否有可能操纵生态位并挽救与年龄相关的干细胞功能衰退。结果：骨干细胞体外形成集落的能力随着年龄的增长而显著下降（* p< 0.05）。等慢性和异慢性异位骨骼干细胞移植试验表明，衰老的骨骼干细胞在肾包膜下形成骨骼的能力功能下降。微ct分析显示老龄小鼠骨密度显著降低（* p< 0.05）。通过骨痂指数测量，该组骨折愈合也延迟。年轻的、系统的微环境使衰老的干细胞恢复活力的能力还有待观察。通过对早期产后小鼠和老年小鼠骨骼干细胞群的微阵列数据分析，发现了可能导致老年骨骼干细胞成骨能力功能下降的差异调节基因。结论：衰老与细胞内在机制的变化有关，这些机制是骨骼干细胞成骨能力功能下降的基础。微阵列分析已经确定了可能导致这种功能下降的差异调节基因。操纵这些途径可能使我们能够逆转骨骼干细胞衰老的影响，并改善体内骨愈合。
PURPOSE:Aging is associated with a gradual loss of homeostatic mechanisms that maintain the structure and function of adult tissues. Most adult tissues contain resident stem cells, which proliferate to compensate for tissue loss throughout the life of the organism. It is believed that both chronological aging and replicative aging of adult stem cells negatively affects their functional capacity for tissue regeneration. Natural aging has a profound effect on skeletal healing, evidenced by the reduced healing ability with advancing age, and an increased incidence of osteoporosis. In mice, we have identified a resident stem-cell pool in skeletal tissue. We can successfully isolate a highly-purified population of skeletal stem cells that have the ability of forming bone, cartilage, stroma and a functioning bone marrow cavity at the clonal level. This study examines the cell-intrinsic mechanisms, and the role of the extrinsic stem cell niche on influencing skeletal stem cell aging. The aim of this study is to identify potential pathways that could be manipulated to reverse the effects of skeletal stem cell aging.METHODS:Highly-purified populations of skeletal stem cells were prospectively isolated by fluorescence-activated cell sorting (FACS) using a novel panel of cell surface markers. Microarray analysis was performed to identify genetic pathways that are differentially regulated with aging. Cell intrinsic function was assayed using isochronic and heterochronic transplantations beneath the kidney capsule to assess their bone-forming ability at an ectopic location. To determine if exposure of aged bone to a young, healthy circulation would improve bone health, we surgically paired mice, creating isochronic and heterochronic parabiosis to determine if it is possible to manipulate the niche and rescue an age-related functional decline in stem cell function.RESULTS:The ability of skeletal stem cells to form colonies in vitro declined significantly with age (* p< 0.05). Isochronic and heterochronic ectopic skeletal stem cell transplantation assays demonstrated a functional decline in the ability of aged skeletal stem cells to form bone beneath the renal capsule. Aged mice demonstrated a significant reduction in bone mineral density using microCT analysis (* p< 0.05). Fracture healing was also delayed in this group, as measured by the callus index. The ability of a young, systemic microenvironment to rejuvenate aged stem cells remains to be seen. Microarray data analysis of skeletal stem cell populations comparing early post-natal to aged mice, has identified differentially regulated genes that may be responsible for the functional decline in the ability of aged skeletal stem cells to form bone.CONCLUSION:Aging is associated with changes in cell-intrinsic mechanisms that underlie the functional decline in the ability of skeletal stem cells to form bone. Microarray analysis has identified differentially regulated genes that may be responsible for this functional decline. Manipulation of these pathways may allow us to reverse the effects of skeletal stem cell aging and improve bone healing in vivo.