title: Interleukin-1beta increases baseline expression and secretion of interleukin-6 by human uveal melanocytes in vitro via the p38 MAPK/NF-kappaB pathway.
abstract: OBJECTIVE
  Melanocyte is the major cell component in the uvea. Interleukin (IL)-6 is a proinflammatory cytokine. The authors studied the expression of IL-6 in cultured human uveal melanocytes (UMs) and their modulation by IL-1β and explored the relevant signal pathways.
  
  
  METHODS
  Conditioned media and cells were collected from UMs cultured in medium with and without serum and were stimulated by IL-1β. IL-6 protein and transcript were measured using an ELISA kit and RT-PCR, respectively. NF-κB in nuclear extracts and phosphorylated p38 MAPK, ERK, and JNK in cells cultured with and without IL-1β were measured by ELISA kits. Inhibitors of p38 (SB203580), ERK (UO1026), JNK (SP600125), and NF-κB (BAY11-7082) were added to the cultures to evaluate their effects.
  
  
  RESULTS
  Low levels of IL-6 protein were detected in the conditioned medium in UMs cultured without serum. The addition of serum increased the secretion of IL-6. IL-1β (0.1-10 ng/mL) increased IL-6 transcript and protein levels in a dose- and time-dependent manner up to sixfold, accompanied by a significant increase of NF-κB in nuclear extracts and phosphorylated p38 MAPK in cell lysates. NF-κB and p38 inhibitors alone decreased, whereas a combination of these two inhibitors completely abolished the IL-1β-induced expression of IL-6.
  
  
  CONCLUSIONS
  This is the first report on the expression and secretion of IL-6 by UMs. IL-1β augments IL-6 production from the melanocytes. The data suggest that UMs may play a role in the pathogenesis of ocular inflammatory and autoimmune diseases.
authors.affiliation: Tissue Culture Center, Department of Pathology, New York Eye and Ear Infirmary, New York Medical College, New York, New York 10003, USA. hu2095@yahoo.com
authors.forename: Dan-Ning
authors.initials: DN
authors.lastname: Hu
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: David Y
authors.initials: DY
authors.lastname: Zhang
authors.forename: Fei
authors.initials: F
authors.lastname: Ye
authors.forename: Steven A
authors.initials: SA
authors.lastname: McCormick
authors.forename: Chi-Chao
authors.initials: CC
authors.lastname: Chan
mesh_terms: D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008544:Melanocytes / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014602:Uvea / Q000166:cytology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; C508600:IL6 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D016328:NF-kappa B; D012333:RNA, Messenger; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases