title: Genomic profiling of messenger RNAs and microRNAs reveals potential mechanisms of TWEAK-induced skeletal muscle wasting in mice.
abstract: BACKGROUND
  Skeletal muscle wasting is a devastating complication of several physiological and pathophysiological conditions. Inflammatory cytokines play an important role in the loss of skeletal muscle mass in various chronic diseases. We have recently reported that proinflammatory cytokine TWEAK is a major muscle-wasting cytokine. Emerging evidence suggests that gene expression is regulated not only at transcriptional level but also at post-transcriptional level through the expression of specific non-coding microRNAs (miRs) which can affect the stability and/or translation of target mRNA. However, the role of miRs in skeletal muscle wasting is unknown.
  
  
  RESULTS
  To understand the mechanism of action of TWEAK in skeletal muscle, we performed mRNA and miRs expression profile of control and TWEAK-treated myotubes. TWEAK increased the expression of a number of genes involved in inflammatory response and fibrosis and reduced the expression of few cytoskeletal gene (e.g. Myh4, Ankrd2, and TCap) and metabolic enzymes (e.g. Pgam2). Low density miR array demonstrated that TWEAK inhibits the expression of several miRs including muscle-specific miR-1-1, miR-1-2, miR-133a, miR-133b and miR-206. The expression of a few miRs including miR-146a and miR-455 was found to be significantly increased in response to TWEAK treatment. Ingenuity pathway analysis showed that several genes affected by TWEAK are known/putative targets of miRs. Our cDNA microarray data are consistent with miRs profiling. The levels of specific mRNAs and miRs were also found to be similarly regulated in atrophying skeletal muscle of transgenic mice (Tg) mice expressing TWEAK.
  
  
  CONCLUSIONS
  Our results suggest that TWEAK affects the expression of several genes and microRNAs involved in inflammatory response, fibrosis, extracellular matrix remodeling, and proteolytic degradation which might be responsible for TWEAK-induced skeletal muscle loss.
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, United States of America.
authors.forename: Siva K
authors.initials: SK
authors.lastname: Panguluri
authors.forename: Shephali
authors.initials: S
authors.lastname: Bhatnagar
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Kumar
authors.forename: John J
authors.initials: JJ
authors.lastname: McCarthy
authors.forename: Apurva K
authors.initials: AK
authors.lastname: Srivastava
authors.forename: Nigel G
authors.initials: NG
authors.lastname: Cooper
authors.forename: Robert F
authors.initials: RF
authors.lastname: Lundy
authors.forename: Ashok
authors.initials: A
authors.lastname: Kumar
mesh_terms: D000818:Animals; D002460:Cell Line; D000074049:Cytokine TWEAK; D020869:Gene Expression Profiling; D023281:Genomics; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D018482:Muscle, Skeletal / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048069:Tumor Necrosis Factors / Q000502:physiology*
chemical_list: D000074049:Cytokine TWEAK; D035683:MicroRNAs; D012333:RNA, Messenger; C491645:Tnfsf12 protein, mouse; D048069:Tumor Necrosis Factors