title: Intermedin/adrenomedullin 2 protects against tubular cell hypoxia-reoxygenation injury in vitro by promoting cell proliferation and upregulating cyclin D1 expression.
abstract: OBJECTIVE
  Intermedin/adrenomedullin 2 (IMD/ADM2) is a newly discovered peptide closely related to adrenomedullin. We recently reported that IMD/ADM2 gene transfer could significantly reduce renal ischaemia/reperfusion injury. In this study, we evaluated the effect of IMD/ADM2 on cell proliferation and regeneration in a cultured rat renal tubular epithelial cell line (NRK-52E) of hypoxia-reoxygenation (H/R) injury.
  
  
  METHODS
  The H/R model in NRK-52E cells consisted of hypoxia for 1 h and reoxygenation for 2 h. IMD/ADM2 was overexpressed in NRK-52E cells using the vector pcDNA3.1-IMD. Enzyme-linked immunosorbent assays were used to measure the concentration of IMD/ADM2 in the culture medium, and real-time PCR and Western blotting were used to determine mRNA and protein levels. In addition, luciferase reporter assays and electrophoretic mobility-shift assays were performed to measure cyclin D1 promoter activity and transcription factor activity.
  
  
  RESULTS
  We found that IMD/ADM2 gene transfer markedly promoted cell viability and decreased lactate dehydrogenase (LDH) activity and cell apoptosis compared with that of H/R. IMD/ADM2 increased the phosphorylation of ERK and decreased the phosphorylation of JNK and P38. Furthermore, IMD/ADM2 promoted cell cycle progression with concomitant increases in the levels of cyclin D1 and cyclin E, and these effects were blocked by the inhibition of ERK, or the agonist JNK and P38. IMD/ADM2 also increased cyclin D1 promoter activity and AP-1 DNA-binding activity.
  
  
  CONCLUSIONS
  We demonstrated that IMD/ADM2 promotes renal cell proliferation and regeneration after renal H/R injury by upregulating cyclin D1 and that this upregulation seems to be mediated by the ERK, JNK, and P38 MAPK signalling pathways.
authors.affiliation: Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan, Shanxi, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Wang
authors.forename: Rongshan
authors.initials: R
authors.lastname: Li
authors.forename: Xi
authors.initials: X
authors.lastname: Qiao
authors.forename: Jihua
authors.initials: J
authors.lastname: Tian
authors.forename: Xiaole
authors.initials: X
authors.lastname: Su
authors.forename: Ruiping
authors.initials: R
authors.lastname: Wu
authors.forename: Ruijing
authors.initials: R
authors.lastname: Zhang
authors.forename: Xiaoshuang
authors.initials: X
authors.lastname: Zhou
authors.forename: Jiaming
authors.initials: J
authors.lastname: Li
authors.forename: Shan
authors.initials: S
authors.lastname: Shao
mesh_terms: D053607:Adrenomedullin / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D015687:Cell Hypoxia; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism*; D019927:Cyclin E / Q000378:metabolism; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D017930:Genes, Reporter; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D007674:Kidney Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007684:Kidney Tubules / Q000098:blood supply* / Q000378:metabolism* / Q000473:pathology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D020935:MAP Kinase Signaling System; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012038:Regeneration; D015427:Reperfusion Injury / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: C530106:Ccnd1 protein, rat; D019927:Cyclin E; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D019938:Cyclin D1; D053607:Adrenomedullin; D007770:L-Lactate Dehydrogenase; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases
keywords: cell proliferation; hypoxia-reoxygenation injury; intermedin/adrenomedullin 2; renal