LncRNA MIAT Upregulates NEGR1 by Competing for miR-150-5p as a Competitive Endogenous RNA in SCIRI Rats.

Objective: Spinal cord ischemia-reperfusion injury (SCIRI) can cause a pathological state of irreversible delayed death of neurons in the spinal cord tissue and a range of complications, such as spinal cord dysfunction and motor function impairment. This study aimed to determine whether the long-stranded non-coding ribonucleic acid (lncRNA), myocardial infarction-associated transcript (MIAT), could upregulate neuronal growth regulator 1 (NEGR1) by competing for miR-150-5p as a competitive endogenous RNA in a rat SCIRI model.

Methods: The MIAT knockdown vector or the corresponding blank vector was injected into the spinal cord of healthy sprague Dawley (SD) rats. Administration of the MIAT knockdown vector led to the establishment of the SCIRI rat model. Basso, Beattie & Bresnahan locomotor rating scale (BBB) assessment of hind limb motion. Pathological changes in the spinal cord were observed via hematoxylin and eosin staining and eosin staining. Quantitative polymerase chain reaction was performed to determine the expression levels of the candidate microRNAs and predicted candidate genes, and the relationship between them. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) staining was used to detect apoptosis in the spinal cord tissue of rats in each group. Western blotting was performed to determine the expression of the apoptosis-related proteins, caspase-9, caspase-3, and BCL2-Associated X (Bax)/B-cell lymphoma-2 (Bcl-2). The luciferase reporter gene was used to assess the interaction among the lncRNA, MIAT, and miR-150-5, and the interaction between miR-150-5 and NEGR1.

Results: The sh-lncRNA, MIAT, improved exercise status, and pathological changes in the spinal cord of SCIRI rats, inhibited apoptosis, increased the expression of miR-150-5p, and reduced the expression of NEGR1. Compared with mimics-NC, the transfection of miR-150-5p significantly decreased the relative fluorescence activity ratio of MIAT 3'-untranslated region (3'-UTR) wild-type Human embryonic kidney cells 293 (HEK-293 cells). Compared with mimics-negative control (NC), the transfection of miR-150-5p significantly decreased the relative fluorescence activity ratio of NEGR1 3'-UTR wild-type HEK-293 cells.

Conclusion: MIAT can affect the symptoms of SCIRI in rats. Furthermore, as a competitive endogenous RNA, MIAT upregulates NEGR1 by competing with miR-150-5p in SCIRI rats.