Inhibition of Human Corneal Myofibroblast Formation #MMPMID30025094
Guo X; Sriram S; Tran JA; Hutcheon AEK; Zieske JD
Invest Ophthalmol Vis Sci 2018[Jul]; 59 (8): 3511-20 PMID30025094show ga
Purpose: Transforming growth factor-beta (TGF-?) isoform 1 (T1) is involved in corneal fibrotic wound healing by stimulating myofibroblast transformation and altering fibrotic gene expression. In this study, two specific inhibitors were used to dissect the relationship between myofibroblast generation and the TGF-?/Smad- or TGF-?/p38-signaling pathway in human corneal fibroblasts (HCF). Methods: In HCF, Trx-SARA (Smad-pathway inhibitor) was used to block the TGF-?/Smad-signaling pathway, and the p38 inhibitor (p38inh, SB202190) was used to inhibit p38MAPK, thus blocking the TGF-?/p38-signaling pathway. HCF ± Trx-SARA or Trx-GA (SARA control) were serum starved overnight in Eagle's minimum essential medium (EMEM) ± p38inh, grown in EMEM ± T1 ± p38inh for 24 hours, and then processed for indirect-immunofluorescence, Western blot, or quantitative real-time polymerase chain reaction to examine ?-smooth muscle actin (?SMA) and other fibrotic genes, such as fibronectin, thrombospondin1, and type III collagen. In addition, the morphology and the effect of p38inh on myofibroblast phenotype after myofibroblast formation were examined. Results: We observed that Trx-SARA had little effect on ?SMA expression, indicating that blocking the Smad pathway did not significantly inhibit myofibroblast formation. However, p38inh did significantly inhibit ?SMA and other fibrotic genes, thus efficiently preventing the transition of HCFs to myofibroblasts. In addition, morphology changed and ?SMA decreased in myofibroblasts exposed to p38inh medium, as compared with controls. Conclusions: HCF transition to myofibroblasts was mainly through the p38 pathway. Therefore, blocking the p38 pathway may be a potential therapeutic tool for human corneal fibrosis prevention/treatment, because it controls myofibroblast formation in human corneal cells, while leaving other functions of T1 unaffected.
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Invest+Ophthalmol+Vis+Sci 2018 ; 59 (8): 3511-20
