[Expression and Regulatory Effect of miR-30b on Dynamin in Cochlear Hair Cells].

OBJECTIVE: To determine the expression of miR-30b in hair cells of mice,and its regulatory effect on the target gene DNM 1 and expression of Dynamin,the key protein of synaptic endocytosis in inner hair cells.

METHODS: The basilar membrane of cochlear in adult C57 mice was obtained. The expression of miR-30b in the hair cells was detected by in situ hybridization. Luciferase vector was constructed and transfected into 293T cells with miR-30b. Changes in luciferase activity were measured to verify whether DNM 1 was the target gene of miR-30b. Adeno-associated virus carrying miR-30b were micro-injected into cochlear via the round window membrane. mRNA expressions of DNM 1 and miR-30b were detected by RT-PCR 14 days later. The expression of Dynamin was detected by Western blot.

RESULTS: miR-30b expressed in the inner and outer hair cells scattered in the region of the nucleus and cytoplasm. miR-30b reduced luciferase activity from the reporter vector containing DNM 11 ( P <0.05),but not in its mutants. Increased expressions of miR-30b and decreased mRNA expressions of DNM 1 and Dynamin were observed following transfection of AAV-miR-30b.

CONCLUSION: miR-30b expresses in inner and outer hair cells,which is consistent with the morphological orientation of dynamin. miR-30b inhibits the expression of Dynamin by targeting DNM 11 gene.