miRNA-221 Regulates Spinal Cord Injury-Induced Inflammatory Response through Targeting TNF-α Expression

• Published in: BioMed research international 2021, Vol.2021, p.6687963-6
• Main Authors: Sun, Feng, Zhang, Haiwei, Huang, Tianwen, Shi, Jianhui, Wei, Tianli, Wang, Yansong
• Format: Article
• Language: English
• Subjects: Animal tissues; Animals; Base Sequence; Bioinformatics; Cell culture; Disease Models, Animal; Down-Regulation - genetics; Enzyme-linked immunosorbent assay; Grip strength; Inflammation; Inflammation - complications; Inflammation - genetics; Inflammation - pathology; Inflammatory response; Injury analysis; Interleukin 6; Male; Mice, Inbred C57BL; Microglia; MicroRNAs; MicroRNAs - genetics; MicroRNAs - metabolism; miRNA; Model testing; Morphology; mRNA; Nervous system; Nitric oxide; Nitric-oxide synthase; Oxidative stress; Proteins; Reagents; Recovery of function; Spinal cord injuries; Spinal Cord Injuries - complications; Spinal Cord Injuries - genetics; Target recognition; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-α; Variance analysis
• ISSN: 2314-6133; 2314-6141
• DOI: 10.1155/2021/6687963

Objectives. To investigate the roles of miR-221 in spinal cord injury (SCI) as well as the underlying mechanism. Methods. A mouse model of SCI was generated and used to examine dynamic changes in grip strength of the mouse upper and lower limbs. The expression of miR-221 and tumor necrosis factor-α (TNF-α) was detected by RT-qPCR and Western blot. Levels of inflammation and oxidative stress in microglia cells of the injured mice overexpressing miR-221 were then measured by ELISA. Bioinformatics analysis and dual-luciferase reporter assay were conducted to identify the miR-221 target. Results. We successfully constructed SCI mouse model. The results of qRT-PCR showed that miR-221 was gradually upregulated in the spinal cord tissue of mice in the SCI group with the prolonged injury time. At the same time, the mRNA and protein of TNF-α gradually decreased. We further confirmed through cell experiments that the inflammatory factors TNF-α and IL-6, as well as iNOS and eROS, were upregulated in spinal cord microglia cells of SCI mice, and upregulation of miR-122 can inhibit their expression. Finally, the luciferase reporter experiment confirmed that miR-122 targeted TNF-α. Conclusions. We present evidence that miR-221 promotes functional recovery of the injured spinal cord through targeting TNF-α, while alleviating inflammatory response and oxidative stress.