2023, Vol. 27 ›› Issue (19): 2993-2998

miR-29a inhibits hydrogen peroxide-induced astrocyte apoptosis by regulating aquaporin-4

Zhu Lin1, Guo Shiwu2, Liu Jinbo2, Zou Hongjun2   

Abstract: BACKGROUND: The role of miR-29a and aquaporin-4 in astrocyte injury has been demonstrated. However, the underlying mechanisms remain largely unknown.  
OBJECTIVE: To investigate the effects of the regulation of aquaporin-4 by miR-29a on hydrogen peroxide-induced astrocyte injury.
METHODS: (1) Primary cultured mouse astrocytes were used to study the damage response of mouse astrocytes induced by different concentrations of hydrogen peroxide, and the cells were divided into control, hydrogen peroxide, hydrogen peroxide + empty vector, and hydrogen peroxide + miR-29a overexpression groups. The survival rate of mouse astrocytes was detected by MTT assay. The protein expression of apoptosis-related proteins (Bcl-2, Bax, and cleaved-Caspase-3), aquaporin-4 and glial fibrillary acidic protein was detected by western blotting. The expression of miR-29a in mouse astrocytes was detected by quantitative reverse transcription-polymerase chain reaction. Mouse astrocyte apoptosis was detected by flow cytometry. (2) Twelve female BALB/c
mice were randomly divided into empty vector and miR-29a overexpression groups with six mice in each group. A T10 spinal cord contusion injury mouse model was established, and the injection of recombinant lentiviral vectors (empty and miR-29a overexpression vectors) was administered after modeling. The expression of aquaporin-4 and glial fibrillary acidic protein at the spinal cord injury site in mice was detected by immunohistochemical staining at 7 days after surgery.  
RESULTS AND CONCLUSION: (1) The activity of astrocytes and the expression of anti-apoptosis protein Bcl-2 were decreased, while the expression of pro-apoptosis proteins Bax and cleaved-caspase-3 was increased in a concentration-dependent manner after hydrogen peroxide-induced injury. In mouse astrocytes with hydrogen peroxide-induced injury, miR-29a expression was decreased, while protein expression of aquaporin-4 and glial fibrillary acidic protein was significantly increased; overexpression of miR-29a inhibited protein expression of aquaporin-4 and apoptosis. Aquaporin-4 may be a downstream target gene of miR-29a as predicted using informatics software. (2) Overexpression of miR-29a at the injury site inhibited the protein expression of aquaporin 4 and glial fibrillary acidic protein in the spinal cord contusion injury mouse model compared with that of the empty vector injection group. (3) These findings suggest that the regulation of aquaporin 4 by miR-29a can inhibit hydrogen peroxide-induced astrocyte apoptosis.

Key words: miRNAs, aquaporin-4, astrocyte, apoptosis, lentivirus, hydrogen peroxide