title: Nephrin is expressed in the pancreatic beta cells.
abstract: OBJECTIVE
  The NPHS1 gene product, nephrin, is a crucial component of the glomerular filtration barrier preventing proteinuria and previously assumed to be kidney-specific. The aim of this study was to describe the expression of nephrin mRNA and protein in human pancreas as well as identify the nephrin-expressing cell types.
  
  
  METHODS
  RNA dot blot, reverse transcriptase-polymerase chain reaction, sequencing, immunoblotting and dual immunofluorescence were used for the characterisation of nephrin in the pancreas.
  
  
  RESULTS
  Except for the kidney, the pancreas was found to be the only tissue expressing nephrin as screened with a human tissue RNA dot blot. The expression was verified with reverse transcriptase-polymerase chain reaction and by sequencing nephrin from a human pancreatic complementary DNA library. Nephrin antibody in immunoblot detected a 165,000 M(r) protein in the pancreas. Dual immunofluorescence showed that nephrin was specifically localised in the beta cells of the islets of Langerhans. There was no overlap with glucagon, somatostatin, or the ductal cell marker cytokeratin 19.
  
  
  CONCLUSIONS
  These data show that nephrin is a novel molecule of pancreatic beta cells.
authors.affiliation: Haartman Institute, Division of Bacteriology and Immunology, University of Helsinki, and Helsinki University Central Hospital Helsinki, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Palmén
authors.forename: H
authors.initials: H
authors.lastname: Ahola
authors.forename: J
authors.initials: J
authors.lastname: Palgi
authors.forename: P
authors.initials: P
authors.lastname: Aaltonen
authors.forename: P
authors.initials: P
authors.lastname: Luimula
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: I
authors.initials: I
authors.lastname: Jaakkola
authors.forename: M
authors.initials: M
authors.lastname: Knip
authors.forename: T
authors.initials: T
authors.lastname: Otonkoski
authors.forename: H
authors.initials: H
authors.lastname: Holthöfer
mesh_terms: D002102:Cadaver; D016650:Fluorescein-5-isothiocyanate; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D015870:Gene Expression; D005934:Glucagon / Q000032:analysis; D006801:Humans; D015151:Immunoblotting; D007515:Islets of Langerhans / Q000378:metabolism*; D007633:Keratins / Q000032:analysis; D007668:Kidney / Q000737:chemistry / Q000196:embryology; D007672:Kidney Cortex / Q000737:chemistry; D008565:Membrane Proteins; D008970:Molecular Weight; D010179:Pancreas / Q000737:chemistry; D011506:Proteins / Q000032:analysis / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013004:Somatostatin / Q000032:analysis
chemical_list: D005456:Fluorescent Dyes; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger; C113267:nephrin; D013004:Somatostatin; D007633:Keratins; D005934:Glucagon; D016650:Fluorescein-5-isothiocyanate