High +Gz Exposure Alters Urinary Extracellular Vesicle miRNAs in Humans

High +Gz exposure elicits complex cardiovascular, autonomic, and endocrine responses, but the associated molecular responses in humans remain poorly understood. We investigated whether microRNAs (miRNAs) encapsulated in urinary extracellular vesicles (uEVs) are altered following acute high +Gz exposure. Twenty-one healthy young men undergoing human centrifuge training provided urine samples before, immediately after, and on the morning after exposure. Candidate uEV-encapsulated miRNAs were identified by RNA sequencing and Gene Ontology analysis, and 16 miRNAs related to ischemia, hypoxia, blood pressure regulation, and mechanical stress were quantified by quantitative PCR. Salivary cortisol, urinary catecholamines, and heart rate were also assessed. Six uEV-encapsulated miRNAs increased significantly after high +Gz exposure. miR-20b-5p, miR-125b-5p, and miR-130a-3p increased immediately after exposure and returned to baseline by the following morning, whereas miR-335-5p, miR-17-5p, and miR-92a-3p remained elevated. Urinary adrenaline, noradrenaline, and dopamine increased immediately after exposure; adrenaline returned to baseline by the following morning, whereas noradrenaline and dopamine remained elevated. Salivary cortisol and heart rate also increased. These findings demonstrate distinct transient and sustained temporal responses of uEV-encapsulated miRNAs to high +Gz in humans, paralleling different catecholamine response patterns. Although their tissue origins and functional roles remain unresolved, these findings provide new molecular-level insights into the human physiological response to high +Gz.