Spatially Resolved Transcriptomic Response of Human Deltoid Skin to Microgravity: A Differential Expression Analysis Using the OSD-574 Dataset

Spaceflight exposure produces dramatic physiological effects, but its influence on human skin has only been clarified partially so far. To investigate molecular mechanisms of the skin reaction to short-term spaceflight, we analyzed openly available transcriptomic data from the NASA GeneLab OSD-574 dataset, including spatially resolved biopsies of SpaceX Inspiration4 crew members' skin. We assumed that mechanical unloading from microgravity would induce downregulation of structure-forming genes used to rebuild the structure of the epidermis. Through differential gene expression from the file “All Layers,” we removed genes that had an adjusted p-value < 0.05 and an absolute log₂ fold change > 1.0. Widespread downregulation of structural genes, which are pertinent for the functioning of the cytoskeleton, such as keratins, desmin, as well as actin-binding proteins, have been revealed. These findings show fast, microgravity-mediated adaptation of the skin through decreased gene expression of load-transmitting genes, which might serve as one of the possible explanations of some of the physiologic changes found upon and following spaceflight by astronauts.