Exosomal miR-21-5p inhibited the neuronal autophagy by increasing miR-21-5p expression in the injured neurons. (A) Real-time PCR showed that expression of miR-21-5p was increased in exosomes harvested from miR-21-5p mimics transfected HT-22 neurons. (B) Real-time PCR showed that miR-21-5p expression was increased in HT22 neurons after scratch injury, and further increasing significantly after treatment with miR-21-5p-overexpressing exosomes. (C–F) Immunoblot analysis of autophagy-related proteins (LC3, P62, Beclin-1) showed that autophagy was induced in the cultured HT-22 neurons after scratch injury. Activation of autophagy was inhibited by neuronal exosomes, especially miR-21-5p-overexpressing exosomes. ** P<0.01, *** P<0.001 versus control group; ##
P<0.01, ###
P<0.001 versus injury group; &
P<0.05, &&
P<0.01 versus injury+ Exo-21+ group.