title: Transcriptional response of peripheral blood mononuclear cells to recombinant human growth hormone in a routine four-days IGF-I generation test.
abstract: BACKGROUND
  There are very few laboratory markers which reflect the biological sensitivity of children to recombinant human growth hormone (rhGH) treatment. Genome-wide transcriptional changes in peripheral blood mononuclear cells (PBMC) have been widely used as functional readout for different pharmacological stimuli.
  
  
  OBJECTIVE
  To characterize transcriptional changes in PBMC induced by rhGH during a routine short-term IGF-I generation test (IGFGT) in children with growth disorders.
  
  
  METHODS
  Blood was obtained for IGF-I determination and RNA-preparation from PBMC of 12 children before and after 4days treatment with 30μgrhGH/kg body weight/day s.c. Transcriptional changes were assessed by cDNA-microarrays in the first six children. Selected genes were validated in all 12 cases by RT-qPCR.
  
  
  RESULTS
  Serum IGF-I rose in all patients except one (p<0.0001), confirming biological response to rhGH. Unsupervised microarray data analysis in the first six children revealed 313 transcripts with abundant transcriptional changes but considerable inter-individual variability of response patterns. Many patients showed a large cluster of up-regulated genes, including EGR1, EGR2, FOS and to a lesser extent STAT2 and 5b. Exemplarily, EGR1, EGR2 and FOS data were independently reproduced by RT-qPCR. Gene ontology analysis revealed that pathways involved in cell proliferation and immune functions were significantly over represented.
  
  
  CONCLUSIONS
  The IGFGT is a suitable method for measuring reproducible and biologically conclusive transcriptional changes in PBMC. As our unsupervised data analysis strategy exposed a considerable inter-individual variability of response profiles a search for molecules of diagnostic and even prognostic value needs to be based on large long-term studies.
authors.affiliation: Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics, Christian-Albrechts University, Kiel, Germany. m.welzel@pediatrics.uni-kiel.de
authors.forename: Maik
authors.initials: M
authors.lastname: Welzel
authors.forename: Mahesh
authors.initials: M
authors.lastname: Appari
authors.forename: Nuria
authors.initials: N
authors.lastname: Bramswig
authors.forename: Felix G
authors.initials: FG
authors.lastname: Riepe
authors.forename: Paul-Martin
authors.initials: PM
authors.lastname: Holterhus
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000378:metabolism*; D002478:Cells, Cultured; D002648:Child; D003940:Diagnostic Techniques, Endocrine; D005260:Female; D020869:Gene Expression Profiling; D006130:Growth Disorders / Q000175:diagnosis / Q000235:genetics*; D019382:Human Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I