Up-Regulation of miR-9-5p Inhibits Hypoxia-Ischemia Brain Damage Through the DDIT4-Mediated Autophagy Pathways in Neonatal Mice

• Published in: Drug design, development and therapy development and therapy, 2023-01, Vol.17, p.1175-1189
• Main Authors: Gai, Chengcheng, Xing, Xiaohui, Song, Yan, Zhao, Yijing, Jiang, Zige, Cheng, Yahong, Xiao, Yilei, Wang, Zhen
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Apoptosis; autophagy; Autophagy - physiology; Beclin-1 - genetics; Brain; Brain - metabolism; Brain damage; ddit4; dna damage-inducible transcript 4; Health aspects; hi; Hypoxia - metabolism; hypoxia-ischemia; Hypoxia-Ischemia, Brain - genetics; Hypoxia-Ischemia, Brain - metabolism; Immunohistochemistry; Infants (Newborn); Injuries; Ischemia; Ischemia - metabolism; Mice; MicroRNA; MicroRNAs - metabolism; mir-9-5p; Original Research; Transcription Factors - metabolism; Up-Regulation
• ISSN: 1177-8881; 1177-8881
• DOI: 10.2147/DDDT.S393362

Hypoxia-ischemia (HI) remains the leading cause of cerebral palsy and long-term neurological sequelae in infants. Despite intensive research and many therapeutic approaches, there are limited neuroprotective strategies against HI insults. Herein, we reported that HI insult significantly down-regulated microRNA-9-5p (miR-9-5p) level in the ipsilateral cortex of neonatal mice. The biological function and expression patterns of protein in the ischemic hemispheres were evaluated by qRT-PCR, Western Blotting analysis, Immunofluorescence and Immunohistochemistry. Open field test and Y-maze test were applied to detect locomotor activity and exploratory behavior and working memory. Overexpression of miR-9-5p effectively alleviated brain injury and improved neurological behaviors following HI insult, accompanying with suppressed neuroinflammation and apoptosis. MiR-9-5p directly bound to the 3' untranslated region of DNA damage-inducible transcript 4 (DDIT4) and negatively regulated its expression. Furthermore, miR-9-5p mimics treatment down-regulated light chain 3 II/light chain 3 I (LC3 II/LC3 I) ratio and Beclin-1 expression and decreased LC3B accumulation in the ipsilateral cortex. Further analysis showed that DDIT4 knockdown conspicuously inhibited the HI-up-regulated LC3 II/ LC3 I ratio and Beclin-1 expression, associating with attenuated brain damage. The study indicates that miR-9-5p-mediated HI injury is regulated by DDIT4-mediated autophagy pathway and up-regulation of miR-9-5p level may provide a potential therapeutic effect on HI brain damage.