Hepatic tissue-derived extracellular vesicles miRNA regulates hypoxia tolerance in Pelteobagrus vachellii by reprogramming metabolism to maintain liver homeostasis

Extracellular vesicles (EVs) mediate intercellular signal communication and perform vital functions in the stress response of aquatic organisms; however, the functional regulatory mechanisms of EVs under hypoxia in fish remain unelucidated. In this study, we optimized enzymatic digestion and combined with ultracentrifugation and high-precision iodixanol density gradient centrifugation, high-purity hepatic EVs were efficiently isolated from Pelteobagrus vachelli, which were internalized by primary hepatocytes successfully.

Integrative analyses of the EVs miRNAome and hepatic transcriptome were performed to construct a miRNA-mRNA negative regulatory network, identifying metabolic reprogramming, HIF-1 signaling, cellular homeostasis and stress response as core pathways in hypoxic adaptation. In vivo functional validation revealed that hypoxia-induced EVs (Hypo-EVs) reduced the critical asphyxiation point, enhanced blood oxygen-carrying capacity, and alleviated hypoxia-induced hepatic oxidative damage in a dose-dependent manner, thereby significantly improving the hypoxia tolerance of P. vachelli.