Genechip analysis of bone marrow osteoprogenitors exposed to microgravity. Mus musculus

In March 2006, murine Bone Marrow Stromal Cells (BMSC) were flown in the Soyuz 12S to the International Space Station to investigate the effects of microgravity on their osteogenic potential in a three-dimensional environment. BMSC were grown in porous bioceramic Skelite disks (Φ 9 mm x T 1.2 mm). The constructs were exposed to microgravity for ca. 8 days, then fixed for RNA extraction. While the flight experiment was performed in fully automated hardware inside the KUBIK incubator, one group of control samples were incubated inside manually operated hardwares (flight control), and the other control group was incubated under routine laboratory conditions (lab control). The altered gene expression profile was analyzed by Mouse Gene 1.0 ST array (Affymetrix) representing whole-transcript coverage. Each one of the 28853 genes is represented on the array by approximately 26 probes spread across the full length of the gene, providing a more complete and more accurate picture of gene expression than the 3’ based expression array design. A few days of microgravity were sufficient to determinate, at least at the molecular level, an effect in the BMSC; this response expressed a stress condition able to determinate consequences on several compartments and cellular functions. In particular, it seems to promote a gene expression, known to be associated with neurogenic activity (e.g. axon guidance), perhaps promoting the BMSC capability to be committed in that direction. The osteo-induction, by dexamethasone-based medium, due to the short duration of stimulation, did not have the possibility to manifest itself at the phenotypic level but only partially at the molecular level. Keywords: gene expression array-based, count Overall design: Comparison of microgravity effects on bone marrow stromal cells maintained both in growth and in osteo-inductive conditions.

2006年3月，小鼠骨髓基质细胞（murine Bone Marrow Stromal Cells, BMSC）搭载联盟12S（Soyuz 12S）飞船前往国际空间站，旨在探究三维培养环境中微重力对其成骨潜能的影响。实验中将BMSC接种于多孔生物陶瓷Skelite圆盘（直径Φ9mm×厚度T1.2mm）中，构建体于微重力环境中培养约8天，随后固定样本以开展RNA提取。本次太空飞行实验在KUBIK培养箱内的全自动硬件系统中完成，其中一组对照样本于手动操作的硬件系统中培养（飞行对照），另一组对照样本则在常规实验室条件下培养（实验室对照）。研究通过代表全转录组覆盖度的小鼠基因1.0 ST芯片（Mouse Gene 1.0 ST array, Affymetrix）分析差异基因表达谱：该芯片上的28853个基因均由约26个均匀分布于基因全长的探针所表征，相较于基于3’端的表达芯片设计，可提供更完整、更准确的基因表达图景。短短数天的微重力暴露已足以在分子层面使BMSC产生响应；该响应体现为一种应激状态，可对多个细胞区室及细胞功能产生后续影响。具体而言，该应激似乎会促进与神经源性活动相关的基因表达（如轴突导向相关基因），或可增强BMSC向该谱系分化的潜能。此外，基于地塞米松的成骨诱导培养基因刺激时长较短，仅能在分子层面部分显现诱导效果，而无法在表型层面体现。关键词：基于基因表达芯片的计数；整体设计：比较微重力对同时处于增殖培养及成骨诱导培养条件下的骨髓基质细胞的影响。