title: The Signature of MicroRNA Dysregulation in Muscle Paralyzed by Spinal Cord Injury Includes Downregulation of MicroRNAs that Target Myostatin Signaling.
abstract: Spinal cord injury (SCI) results in muscle atrophy, reduced force generation and an oxidative-to-glycolytic fiber type shift. The mechanisms responsible for these alterations remain incompletely understood. To gain new insights regarding mechanisms involved in deterioration of muscle after SCI, global expression profiles of miRs in paralyzed gastrocnemius muscle were compared between sham-operated (Sham) and spinal cord-transected (SCI) rats. Ingenuity Pathways Analysis of the altered miRs identified signaling via insulin, IGF-1, integrins and TGF-β as being significantly enriched for target genes. By qPCR, miRs 23a, 23b, 27b, 145, and 206, were downregulated in skeletal muscle 56 days after SCI. Using FISH, miR-145, a miR not previously implicated in the function of skeletal muscle, was found to be localized to skeletal muscle fibers. One predicted target of miR-145 was Cited2, a transcriptional regulator that modulates signaling through NF-κB, Smad3 and other transcription factors. The 3' UTR of Cited2 mRNA contained a highly conserved miR-145 seed sequence. Luciferase reporter assays confirmed that miR-145 interacts with this seed sequence. However, Cited2 protein levels were similar between Sham and SCI groups, indicating a biochemical interaction that was not involved in the context of adaptations after SCI. Taken together, the findings indicate dysregulation of several highly expressed miRs in skeletal muscle after SCI and suggest that reduced expression of miR-23a, 145 and 206 may have roles in alteration in skeletal muscle mass and insulin responsiveness in muscle paralyzed by upper motor neuron injuries.
authors.affiliation: VA RR&D Service National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Medical Center, Bronx, New York.|Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.|Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Rita
authors.initials: R
authors.lastname: De Gasperi
authors.affiliation: VA RR&D Service National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Medical Center, Bronx, New York.|Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Zachary A
authors.identifier: http://orcid.org/0000-0002-6506-7025
authors.initials: ZA
authors.lastname: Graham
authors.affiliation: VA RR&D Service National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Medical Center, Bronx, New York.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Harlow
authors.affiliation: VA RR&D Service National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Medical Center, Bronx, New York.|Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.|Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: William A
authors.initials: WA
authors.lastname: Bauman
authors.affiliation: VA RR&D Service National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Medical Center, Bronx, New York.|Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Weiping
authors.initials: W
authors.lastname: Qin
authors.affiliation: VA RR&D Service National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Medical Center, Bronx, New York.|Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.|Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.|Department of Pharmacologic Science Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Cardozo
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000235:genetics* / Q000473:pathology; D055435:Myostatin / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D015398:Signal Transduction; D013119:Spinal Cord Injuries / Q000235:genetics* / Q000473:pathology
chemical_list: D007328:Insulin; D035683:MicroRNAs; D055435:Myostatin; D012333:RNA, Messenger; C542511:MIRN145 microRNA, rat; C000590974:MIRN23a microRNA, rat; C522220:mirn206 microRNA, rat