6-day Dry Immersion leads to downregulation of slow-fiber type and mitochondria-related genes expression.

The soleus muscle in humans is responsible for maintaining an upright posture and participates in walking and running. Under muscle disuse, it undergoes molecular signaling changes that result in altered force and work capacity. The triggering mechanisms and pathways of these changes are not yet fully understood. In this article, we aimed to detect the molecular pathways that are involved in the unloading-induced alterations in the human soleus muscle under 6-days of dry immersion. A 6-day dry immersion led to the downregulation of mitochondrial biogenesis and dynamics markers, upregulation of calcium-dependent CaMK II phosphorylation, enhanced PGC1α promoter region methylation and altered muscle micro-RNA expression, without affecting p-AMPK content or fiber-type transformation.