title: Adenine induces differentiation of rat hepatic stellate cells.
abstract: OBJECTIVE
  Adenine is a uric acid pathway metabolite of no known function, and has recently been identified as a ligand for a rat G protein-coupled receptor. Due to the known role of other uric acid pathway metabolites in HSC biology, we tested the ability of adenine to induce HSC differentiation.
  
  
  METHODS
  RT-PCR was performed for adenine receptor expression in T-6 and primary rat HSC. T-6 and primary rats HSC were cultured with and without adenine, and stellation examined. Next, we examined inhibition of calcium signaling using caged IP(3). To test if adenine inhibits HSC chemotaxis T-6 cells and rat HSCs were cultured with or without adenine for 24 h in a transwell assay with PDGF as the chemoattractant. cDNA was prepared from T-6 and primary HSC for quantification of collagen 1 mRNA using real-time PCR.
  
  
  RESULTS
  We found that mRNA for the adenine receptor is expressed in T-6 cells and primary rat HSC. Also, adenine induces HSC stellation and adenine inhibits IP(3) mediated increase in cytosolic [Ca(2+)](i) and inhibits chemotaxis in T-6 cells and primary rat HSC. Adenine was also shown to up-regulate α-SMA and collagen 1, and this effect is lost by using specific si-RNA for the adenine receptor. Finally, adenine inhibits endothelin-1-induced gel contraction.
  
  
  CONCLUSIONS
  The adenine receptor is present in T-6 cells and primary rats HSC. Adenine, via the adenine receptor, induces morphological change, and cytosolic calcium signaling, inhibits chemotaxis, and up-regulates collagen 1 mRNA in HSCs.
authors.affiliation: Section of Digestive Diseases, Yale University, 1080 LMP, PO Box. 208019, New Haven, CT 06520-8019, USA. azuma.watanabe@hotmail.com
authors.forename: Azuma
authors.initials: A
authors.lastname: Watanabe
authors.forename: Muhammad Adnan
authors.initials: MA
authors.lastname: Sohail
authors.forename: Samir
authors.initials: S
authors.lastname: Gautam
authors.forename: Dawidson Assis
authors.initials: DA
authors.lastname: Gomes
authors.forename: Wajahat Zafar
authors.initials: WZ
authors.lastname: Mehal
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000225:Adenine / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation; D002633:Chemotaxis; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D055166:Hepatic Stellate Cells / Q000166:cytology / Q000187:drug effects*; D015544:Inositol 1,4,5-Trisphosphate / Q000235:genetics / Q000378:metabolism; D008665:Metalloporphyrins; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011983:Receptors, Purinergic / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000199:Actins; D000225:Adenine; D024042:Collagen Type I; D018076:DNA, Complementary; D019332:Endothelin-1; D015544:Inositol 1,4,5-Trisphosphate; D008665:Metalloporphyrins; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D011983:Receptors, Purinergic; C459899:adenine receptor, rat; C441603:meso-tetra(4-methylpyridinium)porphyrinato copper(II); C498862:Acta2 protein, rat