TGF-beta-induced interleukin-6 participates in transdifferentiation of human Tenon's fibroblasts to myofibroblasts.
OBJECTIVE
To gain a better understanding of the roles of interleukins (ILs) in subconjunctival fibrosis, we investigated their expression in transforming growth factor-beta1 (TGF-beta1)-stimulated Tenon's fibroblasts and examined their association with the transdifferentiation of fibroblasts to myofibroblasts.


METHODS
After primary culture, fibroblasts derived from human Tenon's capsule were exposed to TGF-beta1. The expression of alpha-smooth muscle actin (alpha-SMA) protein was assessed by western immunoblots and immunofluorescence. The mRNA levels of various ILs were also evaluated by multiplex reverse transcription (RT)-PCR. Using the small interfering RNAs (siRNAs) specific for IL-6 and IL-11 and the promoter deletion assay, the contributions of IL-6 and IL-11 to TGF-beta1-induced induction of alpha-SMA were determined.


RESULTS
In human Tenon's fibroblasts, TGF-beta1 stimulated the expression of alpha-SMA protein determined by western blot analysis and also increased the mRNA levels of IL-6 and IL-11 determined by multiplex RT-PCR. On the western immunoblots and immunofluorescence, the increased expression of alpha-SMA was attenuated only by the siRNAs specific for IL-6 but not by the siRNAs specific for IL-11. When the activator protein-1 binding sites of the IL-6 promoter region were deleted, the stimulation effects of TGF-beta1 decreased.


CONCLUSIONS
Our data show that autocrine IL-6 may participate in the TGF-beta1-induced transdifferentiation of human Tenon's fibroblasts to myofibroblasts, which is known to be an essential step for subconjunctival fibrosis.
Seong
Gong Je
GJ
Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
Hong
Samin
S
Jung
Sun-Ah
SA
Lee
Jung-Jin
JJ
Lim
Eunhae
E
Kim
Sung-Joo
SJ
Lee
Joon H
JH
D000199:Actins / Q000378:metabolism; D015153:Blotting, Western; D054338:Cell Transdifferentiation / Q000187:drug effects*; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D017370:Interleukin-11 / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D034622:RNA Interference / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D018808:Transcription Factor AP-1 / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
D000199:Actins; D017370:Interleukin-11; D015850:Interleukin-6; D034741:RNA, Small Interfering; D018808:Transcription Factor AP-1; D016212:Transforming Growth Factor beta