title: ANKRD1 modulates inflammatory responses in C2C12 myoblasts through feedback inhibition of NF-κB signaling activity.
abstract: Transcription factors of the nuclear factor-kappa B (NF-κB) family play a pivotal role in inflammation, immunity and cell survival responses. Recent studies revealed that NF-κB also regulates the processes of muscle atrophy. NF-κB activity is regulated by various factors, including ankyrin repeat domain 2 (AnkrD2), which belongs to the muscle ankyrin repeat protein family. Another member of this family, AnkrD1 is also a transcriptional effector. The expression levels of AnkrD1 are highly upregulated in denervated skeletal muscle, suggesting an involvement of AnkrD1 in NF-κB mediated cellular responses to paralysis. However, the molecular mechanism underlying the interactive role of AnkrD1 in NF-κB mediated cellular responses is not well understood. In the current study, we examined the effect of AnkrD1 on NF-κB activity and determined the interactions between AnkrD1 expression and NF-κB signaling induced by TNFα in differentiating C2C12 myoblasts. TNFα upregulated AnkrD1 mRNA and protein levels. AnkrD1-siRNA significantly increased TNFα-induced transcriptional activation of NF-κB, whereas overexpression of AnkrD1 inhibited TNFα-induced NF-κB activity. Co-immunoprecipitation studies demonstrated that AnkrD1 was able to bind p50 subunit of NF-κB and vice versa. Finally, CHIP assays revealed that AnkrD1 bound chromatin at a NF-κB binding site in the AnrkD2 promoter and required NF-κB to do so. These results provide evidence of signaling integration between AnkrD1 and NF-κB pathways, and suggest a novel anti-inflammatory role of AnkrD1 through feedback inhibition of NF-κB transcriptional activity by which AnkrD1 modulates the balance between physiological and pathological inflammatory responses in skeletal muscle.
authors.affiliation: National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468, USA; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Liu
authors.affiliation: National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468, USA; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Bauman
authors.affiliation: National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, NY 10468, USA; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Electronic address: chris.cardozo@va.gov.
authors.forename: Christopher
authors.initials: C
authors.lastname: Cardozo
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D002470:Cell Survival; D002843:Chromatin / Q000378:metabolism; D025461:Feedback, Physiological; D005786:Gene Expression Regulation; D007249:Inflammation / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D009124:Muscle Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D032446:Myoblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: C104844:Ankrd1 protein, mouse; C485877:Ankrd2 protein, mouse; D002843:Chromatin; D009124:Muscle Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D014409:Tumor Necrosis Factor-alpha
keywords: AnkrD1; Inflammation; Myoblasts; NF-kB signaling