RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan.
Laboratory of Developmental Genetics, Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan.
Sci Rep. 2019 May 21;9(1):7654. doi: 10.1038/s41598-019-44067-9.
Secondary lymphoid organs are critical for regulating acquired immune responses. The aim of this study was to characterize the impact of spaceflight on secondary lymphoid organs at the molecular level. We analysed the spleens and lymph nodes from mice flown aboard the International Space Station (ISS) in orbit for 35 days, as part of a Japan Aerospace Exploration Agency mission. During flight, half of the mice were exposed to 1 g by centrifuging in the ISS, to provide information regarding the effect of microgravity and 1 g exposure during spaceflight. Whole-transcript cDNA sequencing (RNA-Seq) analysis of the spleen suggested that erythrocyte-related genes regulated by the transcription factor GATA1 were significantly down-regulated in ISS-flown vs. ground control mice. GATA1 and Tal1 (regulators of erythropoiesis) mRNA expression was consistently reduced by approximately half. These reductions were not completely alleviated by 1 g exposure in the ISS, suggesting that the combined effect of space environments aside from microgravity could down-regulate gene expression in the spleen. Additionally, plasma immunoglobulin concentrations were slightly altered in ISS-flown mice. Overall, our data suggest that spaceflight might disturb the homeostatic gene expression of the spleen through a combination of microgravity and other environmental changes.
次级淋巴器官对于调节获得性免疫反应至关重要。本研究旨在从分子水平上描述飞行对次级淋巴器官的影响。我们分析了在国际空间站（ISS）轨道上飞行 35 天的小鼠的脾脏和淋巴结，这是日本宇宙航空研究开发机构任务的一部分。在飞行过程中，一半的小鼠在 ISS 中通过离心力暴露于 1g 环境中，以提供有关微重力和飞行中 1g 暴露的影响的信息。对脾脏的全转录 cDNA 测序（RNA-Seq）分析表明，与地面对照小鼠相比，由转录因子 GATA1 调节的红细胞相关基因在 ISS 飞行小鼠中显著下调。GATA1 和 Tal1（红细胞生成的调节剂）mRNA 表达一致减少约一半。这些减少在 ISS 中的 1g 暴露下并未完全缓解，表明除微重力之外的空间环境的综合影响可能下调脾脏中的基因表达。此外，ISS 飞行小鼠的血浆免疫球蛋白浓度略有改变。总体而言，我们的数据表明，飞行可能通过微重力和其他环境变化的组合扰乱脾脏的稳态基因表达。
