title: Glucose-induced expression of the homeotic transcription factor Prep1 is associated with histone post-translational modifications in skeletal muscle.
abstract: OBJECTIVE
  Chronic hyperglycaemia worsens insulin resistance in individuals with type 2 diabetes. Whether this effect is contributed by epigenetic dysregulation and which genes are involved remain unclear. Prep1 (also known as Pknox1) is a gene exerting major effects on the sensitivity of the glucose transport machinery to insulin. Here, we show that dysregulation of Prep1 expression by high glucose levels is associated with histone modifications at its 5' regulatory region.
  
  
  METHODS
  We used mouse and cell models to investigate Prep1 transcriptional regulation by glucose.
  
  
  RESULTS
  Differentiated L6 skeletal muscle cells were grown in the presence of either 5.5 or 25 mmol/l glucose (normal [NG] and high glucose [HG], respectively). The HG exposure increased nuclear factor κ light chain enhancer of activated B cells (NF-κB) p65 binding and recruitment of the su(var)3-9, enhancer-of-zeste, trithorax domain-containing lysine methyltransferase 7 (SET7) histone methyltransferase and p300 acetyltransferase to the 5' region of Prep1, leading to enhanced transcription. In addition, chromatin immunoprecipitation assays revealed concomitantly increased histone H3 mono- and dimethylation and acetylation at Lys4 and Lys9/14, respectively. Skeletal muscle tissue from streptozotocin-treated diabetic mice also showed Prep1 overexpression accompanied by similarly increased recruitment of NF-κB p65 and histone modifications at the 5' region of Prep1. In these same mice, as well as in Prep1-overexpressing L6 cells, Prep1-induced recruitment of the repressor complex myocyte enhancer factor 2 (MEF2)/histone deacetylase 5 (HDAC5) at the Glut4 promoter was also increased, leading to reduced Glut4 expression.
  
  
  CONCLUSIONS
  These studies indicate that HG exposure induces NF-κB recruitment and histone modification at the Prep1 5' region, thereby enhancing the transcription of Prep1 and repressing that of Glut4. Histone changes at the Prep1 gene may contribute to insulin resistance in individuals with type 2 diabetes.
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Ciccarelli
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: Vastolo
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Albano
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Lecce
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Cabaro
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Antonietta
authors.initials: A
authors.lastname: Liotti
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Longo
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Oriente
authors.affiliation: Istituto di Scienze dell'Alimentazione, Consiglio Nazionale delle Ricerche, Avellino, Italy.
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Russo
authors.affiliation: Dipartimento di Medicina Clinica e Chirurgia, Università degli Studi di Napoli, 'Federico II', Naples, Italy.
authors.forename: Paolo Emidio
authors.initials: PE
authors.lastname: Macchia
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Formisano
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Beguinot
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli, 'Federico II', Naples, Italy. pungaro@ieos.cnr.it.|URT 'Genomica Funzionale' Istituto di Endocrinologia ed Oncologia Sperimentale, 'G. Salvatore', Consiglio Nazionale delle Ricerche, Via Sergio Pansini, 5, 80131, Naples, Italy. pungaro@ieos.cnr.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Ungaro
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002460:Cell Line; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000378:metabolism; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation; D005947:Glucose / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D007249:Inflammation; D007333:Insulin Resistance; D064326:MEF2 Transcription Factors / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011499:Protein Processing, Post-Translational
chemical_list: D001786:Blood Glucose; D006657:Histones; D018398:Homeodomain Proteins; D064326:MEF2 Transcription Factors; D016328:NF-kappa B; C491412:Pknox1 protein, mouse; D005947:Glucose
keywords: Chromatin remodelling; GLUT4; Histone-modification enzymes; NF-κB; Prep1; Type 2 diabetes