title: Interferon-stimulated gene 15 (ISG15) conjugates proteins in dermatomyositis muscle with perifascicular atrophy.
abstract: OBJECTIVE
  We investigated interferon-stimulated gene 15 (ISG15), a poorly understood ubiquitin-like modifier, and its enzymatic pathway in dermatomyositis (DM), an autoimmune disease primarily involving muscle and skin.
  
  
  METHODS
  We generated microarray data measuring transcript abundance for approximately 18,000 genes in each of 113 human muscle biopsy specimens, and studied biopsy specimens and cultured skeletal muscle using immunohistochemistry, immunoblotting proteomics, real-time quantitative polymerase chain reaction, and laser-capture microdissection.
  
  
  RESULTS
  Transcripts encoding ISG15-conjugation pathway proteins were markedly upregulated in DM with perifascicular atrophy (DM-PFA) muscle (ISG15 339-fold, HERC5 62-fold, and USP18 68-fold) compared with 99 non-DM samples. Combined analysis with publicly available microarray datasets showed that >50-fold ISG15 transcript elevation had 100% sensitivity and specificity for 28 biopsies from adult DM-PFA and juvenile DM patients compared with 199 muscle samples from other muscle diseases. Free ISG15 and ISG15-conjugated proteins were only found on immunoblots from DM-PFA muscle. Cultured human skeletal muscle exposed to type 1 interferons produced similar transcripts and ISG15 protein and conjugates. Laser-capture microdissection followed by proteomic analysis showed deficiency of titin in DM perifascicular atrophic myofibers.
  
  
  CONCLUSIONS
  A large-scale microarray study of muscle samples demonstrated that among a diverse group of muscle diseases DM was uniquely associated with upregulation of the ISG15 conjugation pathway. Exposure of human skeletal muscle cell culture to type 1 interferons produced a molecular picture highly similar to that seen in human DM muscle. Perifascicular atrophic myofibers in DM were deficient in a number of skeletal muscle proteins including titin.
authors.affiliation: Children's Hospital Informatics Program, Division of Neuromuscular Disease, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Salajegheh
authors.forename: Sek Won
authors.initials: SW
authors.lastname: Kong
authors.forename: Jack L
authors.initials: JL
authors.lastname: Pinkus
authors.forename: Ronan J
authors.initials: RJ
authors.lastname: Walsh
authors.forename: Anne
authors.initials: A
authors.lastname: Liao
authors.forename: Remedios
authors.initials: R
authors.lastname: Nazareno
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Amato
authors.forename: Bryan
authors.initials: B
authors.lastname: Krastins
authors.forename: Chris
authors.initials: C
authors.lastname: Morehouse
authors.forename: Brandon W
authors.initials: BW
authors.lastname: Higgs
authors.forename: Bahija
authors.initials: B
authors.lastname: Jallal
authors.forename: Yihong
authors.initials: Y
authors.lastname: Yao
authors.forename: David A
authors.initials: DA
authors.lastname: Sarracino
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Parker
authors.forename: Steven A
authors.initials: SA
authors.lastname: Greenberg
mesh_terms: D002478:Cells, Cultured; D064211:Connectin; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D030541:Databases, Genetic; D003882:Dermatomyositis / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007370:Interferon Type I / Q000378:metabolism; D007834:Lasers; D042282:Microdissection / Q000379:methods; D009124:Muscle Proteins / Q000172:deficiency; D018482:Muscle, Skeletal / Q000378:metabolism*; D009135:Muscular Diseases / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000172:deficiency; D040901:Proteomics / Q000379:methods; D012680:Sensitivity and Specificity; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D064211:Connectin; D016207:Cytokines; D007370:Interferon Type I; D009124:Muscle Proteins; C577285:TTN protein, human; D014452:Ubiquitins; C074034:ISG15 protein, human; D011494:Protein Kinases