Faculty of Medicine, Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Air Force Center, Innovation Cluster Space and Aviation (UZH Space Hub), University of Zurich, Überlandstrasse 271, 8600 Dübendorf, Switzerland.
Int J Mol Sci. 2021 Aug 6;22(16):8451. doi: 10.3390/ijms22168451.
Cellular responses to micro- and hypergravity are rapid and complex and appear within the first few seconds of exposure. Transcriptomic analyses are a valuable tool to analyze these genome-wide cellular alterations. For a better understanding of the cellular dynamics upon altered gravity exposure, it is important to compare different time points. However, since most of the experiments are designed as endpoint measurements, the combination of cross-experiment meta-studies is inevitable. Microarray and RNA-Seq analyses are two of the main methods to study transcriptomics. In the field of altered gravity research, both methods are frequently used. However, the generation of these data sets is difficult and time-consuming and therefore the number of available data sets in this research field is limited. In this study, we investigated the comparability of microarray and RNA-Seq data and applied the results to a comparison of the transcriptomics dynamics between the hypergravity conditions during two real flight platforms and a centrifuge experiment to identify temporal adaptation processes. We performed a comparative study on an Affymetrix HTA2.0 microarray and a paired-end RNA-Seq data set originating from the same Jurkat T cell RNA samples from a short-term hypergravity experiment. The overall agreeability was high, with better sensitivity of the RNA-Seq analysis. The microarray data set showed weaknesses on the level of single upregulated genes, likely due to its normalization approach. On an aggregated level of biotypes, chromosomal distribution, and gene sets, both technologies performed equally well. The microarray showed better performance on the detection of altered gravity-related splicing events. We found that all initially altered transcripts fully adapted after 15 min to hypergravity and concluded that the altered gene expression response to hypergravity is transient and fully reversible. Based on the combined multiple-platform meta-analysis, we could demonstrate rapid transcriptional adaptation to hypergravity, the differential expression of the ATPase subunits ATP6V1A and ATP6V1D, and the cluster of differentiation (CD) molecules CD1E, CD2AP, CD46, CD47, CD53, CD69, CD96, CD164, and CD226 in hypergravity. We could experimentally demonstrate that it is possible to develop methodological evidence for the meta-analysis of individual data.
细胞对微重力和超重力的反应迅速而复杂,在暴露的最初几秒钟内就会出现。转录组分析是分析这些全基因组细胞变化的一种有价值的工具。为了更好地理解重力改变后细胞的动力学,比较不同的时间点是很重要的。然而,由于大多数实验都是作为终点测量设计的,因此不可避免地需要进行跨实验的元研究组合。微阵列和 RNA-Seq 分析是研究转录组学的两种主要方法。在改变重力的研究领域,这两种方法都经常被使用。然而,这些数据集的生成既困难又耗时,因此这个研究领域的可用数据集数量有限。在这项研究中,我们研究了微阵列和 RNA-Seq 数据的可比性,并将结果应用于比较两种真实飞行平台的超重力条件和离心实验之间的转录组学动态,以鉴定时间适应过程。我们对来自短期超重力实验的相同 Jurkat T 细胞 RNA 样本的 Affymetrix HTA2.0 微阵列和配对末端 RNA-Seq 数据集进行了比较研究。整体一致性很高,RNA-Seq 分析的灵敏度更好。微阵列数据集在单个上调基因的水平上表现较弱,可能是由于其归一化方法。在生物类型、染色体分布和基因集的综合水平上,两种技术的表现同样出色。微阵列在检测与重力改变相关的剪接事件方面表现更好。我们发现,所有最初改变的转录本在 15 分钟后完全适应超重力,得出结论,超重力对基因表达的改变反应是短暂的和完全可逆的。基于组合的多平台元分析,我们能够证明超重力的快速转录适应性,ATP 酶亚基 ATP6V1A 和 ATP6V1D 的差异表达,以及分化簇 (CD) 分子 CD1E、CD2AP、CD46、CD47、CD53、CD69、CD96、CD164 和 CD226 在超重力中的聚类。我们可以通过实验证明,为个别数据的元分析开发方法学证据是可行的。