title: Expressional reprogramming of survival pathways in rat cardiocytes by neuregulin-1beta.
abstract: Neuregulin/ErbB2-induced kinase signaling provides essential survival and protection clues for functional integrity of the adult heart and skeletal muscle. To define the regulatory pathways involved in neuregulin-dependent muscle cell survival, we set out to map the largely unknown transcript targets of this growth/differentiation factor in cardiocytes. Freshly isolated adult primary rat cardiocytes were treated for 24 h with recombinant human neuregulin-1beta (NRG-1beta, 30 ng/ml). Transcript level alterations in NRG-1beta-treated and control cardiocytes (n = 6) were identified with Atlas Rat Toxicology 1.2 cDNA arrays (BD Clontech) and established permutation L1 regression analysis. Selected transcriptional adjustments were confirmed by RT-PCR and Western blotting. Involvement of MAPK pathways was verified with the inhibitor PD-98059. Application of the single dose of NRG-1beta to quiescent cardiocytes induced expressional reprogramming of distinct cellular processes. This response included a prominent 50-100% increase in transcripts of multiple redox systems. It also involved a comparable mRNA augmentation of protein synthetic and folding factors together with augmented message for the trigger of cardiac hypertrophy, cyclin D1 (CCND1). First evidence for a role of neuregulin in promotion of mitochondrial turnover, voltage-gated ion channel expression, and the suppression of fatty acid transporter mRNAs was revealed. Subsequent analysis confirmed a corresponding upregulation of redox factor proteins thioredoxin and the thioredoxin reductase 1, GSTP-1, and CCND1 and demonstrated downregulation of the related transcripts by PD-98059 in neuregulin-stimulated cultures. These MAPK-dependent expressional adjustments point to novel oxidative defense and hypertrophy pathways being involved in the longer lasting protective function of neuregulin in the heart.
authors.affiliation: Swiss Cardiovascular Center, Bern, Switzerland.
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Giraud
authors.forename: Martin
authors.initials: M
authors.lastname: Flück
authors.forename: Christian
authors.initials: C
authors.lastname: Zuppinger
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Suter
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology*; D020890:Neuregulin-1 / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D009124:Muscle Proteins; D020890:Neuregulin-1; D011994:Recombinant Proteins; C117467:neuregulin beta