title: A SAGE based approach to human glomerular endothelium: defining the transcriptome, finding a novel molecule and highlighting endothelial diversity.
abstract: BACKGROUND
  Large scale transcript analysis of human glomerular microvascular endothelial cells (HGMEC) has never been accomplished. We designed this study to define the transcriptome of HGMEC and facilitate a better characterization of these endothelial cells with unique features. Serial analysis of gene expression (SAGE) was used for its unbiased approach to quantitative acquisition of transcripts.
  
  
  RESULTS
  We generated a HGMEC SAGE library consisting of 68,987 transcript tags. Then taking advantage of large public databases and advanced bioinformatics we compared the HGMEC SAGE library with a SAGE library of non-cultured ex vivo human glomeruli (44,334 tags) which contained endothelial cells. The 823 tags common to both which would have the potential to be expressed in vivo were subsequently checked against 822,008 tags from 16 non-glomerular endothelial SAGE libraries. This resulted in 268 transcript tags differentially overexpressed in HGMEC compared to non-glomerular endothelia. These tags were filtered using a set of criteria: never before shown in kidney or any type of endothelial cell, absent in all nephron regions except the glomerulus, more highly expressed than statistically expected in HGMEC. Neurogranin, a direct target of thyroid hormone action which had been thought to be brain specific and never shown in endothelial cells before, fulfilled these criteria. Its expression in glomerular endothelium in vitro and in vivo was then verified by real-time-PCR, sequencing and immunohistochemistry.
  
  
  CONCLUSIONS
  Our results represent an extensive molecular characterization of HGMEC beyond a mere database, underline the endothelial heterogeneity, and propose neurogranin as a potential link in the kidney-thyroid axis.
authors.affiliation: Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Waehringer Guertel 18 - 20, A-1090 Vienna, Austria. guerkan.sengoelge@meduniwien.ac.at.
authors.forename: Guerkan
authors.initials: G
authors.lastname: Sengoelge
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Winnicki
authors.forename: Anne
authors.initials: A
authors.lastname: Kupczok
authors.forename: Arndt
authors.initials: A
authors.lastname: von Haeseler
authors.forename: Michael
authors.initials: M
authors.lastname: Schuster
authors.forename: Walter
authors.initials: W
authors.lastname: Pfaller
authors.forename: Paul
authors.initials: P
authors.lastname: Jennings
authors.forename: Ansgar
authors.initials: A
authors.lastname: Weltermann
authors.forename: Sophia
authors.initials: S
authors.lastname: Blake
authors.forename: Gere
authors.initials: G
authors.lastname: Sunder-Plassmann
mesh_terms: D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology; D020869:Gene Expression Profiling / Q000379:methods* / Q000592:standards; D063990:Gene Ontology; D006801:Humans; D007678:Kidney Glomerulus / Q000098:blood supply / Q000378:metabolism; D055806:Microvessels / Q000166:cytology; D051579:Neurogranin / Q000235:genetics / Q000378:metabolism; D012015:Reference Standards; D059467:Transcriptome
chemical_list: C496649:NRGN protein, human; D051579:Neurogranin