title: Interferon-gamma differentially regulates TGF-beta1 and TGF-beta2 expression in human retinal pigment epithelial cells through JAK-STAT pathway.
abstract: Retinal pigment epithelium (RPE) and transforming growth factor-beta (TGF-beta) have been shown to be involved in various retinal diseases. We have studied the role of inflammatory cytokines on the expression and secretion of TGF-beta in human RPE cells (HRPE). Confluent cultures of HRPE derived from donor eyes were used. RT-PCR analyses showed that TNF-alpha and IL-1beta increased the mRNA levels of both TGF-beta1 and TGF-beta2. IFN-gamma enhanced constitutively expressed, as well as, TNF-alpha-and IL-1beta-induced TGF-beta1 mRNA levels but decreased TGF-beta2 mRNA. The effects of these cytokines on TGF-beta1 and TGF-beta2 secretion correlated with the mRNA levels. TGF-beta1 was always produced as the latent form while 21-31% of TGF-beta2 was in the active form. IFN-gamma reduced the production of active form of TGF-beta2 to 4-9%. TGF-beta3 secretion was not detectable under any of the conditions. The Real-Time PCR analysis of TGF-beta mRNAs confirmed the observed results. The TGF-beta1 and TGF-beta2 secretion was induced by TGF-beta2 and TGF-beta1, respectively. Under these conditions, the contrasting effects of IFN-gamma on TGF-beta1 and TGF-beta2 secretion were also observed. JAK inhibitor selectively inhibited IFN-gamma induced TGF-beta1 secretion and mRNA levels while reversing the inhibitory effects of IFN-gamma on TGF-beta2. Analyses of transcription factor activity strongly indicated the role of STAT-1 but not NFkappaB, C-Myc, C-Jun, SP-1, MEF-2. Our data demonstrate that IFN-gamma differentially regulates constitutively expressed, as well as, cytokine-induced TGF-beta1 and TGF-beta2 mRNA levels and secretion of TGF-betas by HRPE.
authors.affiliation: Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Chandrasekharam N
authors.initials: CN
authors.lastname: Nagineni
authors.forename: Karthik S
authors.initials: KS
authors.lastname: Cherukuri
authors.forename: Veena
authors.initials: V
authors.lastname: Kutty
authors.forename: Barbara
authors.initials: B
authors.lastname: Detrick
authors.forename: John J
authors.initials: JJ
authors.lastname: Hooks
mesh_terms: D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D053583:Interleukin-1beta / Q000494:pharmacology; D053612:Janus Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017471:Receptors, Interferon / Q000819:agonists / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050791:STAT Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D053781:Transforming Growth Factor beta2 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D000096743:Interferon gamma Receptor
chemical_list: D000911:Antibodies, Monoclonal; D007371:Interferon-gamma; D053583:Interleukin-1beta; D053612:Janus Kinases; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D017471:Receptors, Interferon; D050791:STAT Transcription Factors; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D014409:Tumor Necrosis Factor-alpha; D000096743:Interferon gamma Receptor