1-Methyl-L-tryptophan promotes the apoptosis of hepatic stellate cells arrested by interferon-γ by increasing the expression of IFN-γRβ, IRF-1 and FAS

  • Authors:
    • Ji Eun Oh
    • Kwang Yong Shim
    • Jong In Lee
    • Soo In Choi
    • Soon Koo Baik
    • Young Woo Eom
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  • Published online on: June 26, 2017     https://doi.org/10.3892/ijmm.2017.3043
  • Pages: 576-582
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Abstract

Liver fibrosis, a precursor to cirrhosis, is the result of the deposition of extracellular matrix (ECM) proteins and is mediated primarily by activated hepatic stellate cells (HSCs). In this study, we investigated the anti-fibrotic effects of interferon (IFN)-γ in activated HSCs in vitro and whether cell viability would be decreased by the inhibition of indoleamine 2,3-dioxygemase (IDO), which is responsible for cell cycle arrest. Following treatment with IFN-γ, cell signaling pathways and DNA content were analyzed to assess the inactivation of HSCs or the decrease in HSC proliferation. The IDO inhibitor, 1-methyl-L-tryptophan (1-MT), was used to determine whether IDO plays a key role in the regulation of activated HSCs, as IFN-γ increases the expression of IDO. IFN-γ significantly inhibited the growth of HSCs and downregulated the expression of α-smooth muscle actin (α-SMA) in the HSCs. IDO expression was markedly increased by IFN-γ through signal transducer and activator of transcription 1 (STAT1) activation and resulted in the depletion of tryptophan. This depletion induced G1 cell cycle arrest. When the cells were released from IFN-γ-mediated G1 cell cycle arrest by treatment with 1-MT, the apoptosis of the HSCs was markedly increased through the induction of IFN-γRβ, interferon regulatory factor (IRF-1) and FAS. Our results thus suggest that the inhibition of IDO enhances the suppression of activated HSCs, and therefore co-treatment with IFN-γ and 1-MT may be applied to ameliorate liver fibrosis.
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August-2017
Volume 40 Issue 2

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Oh JE, Shim KY, Lee JI, Choi SI, Baik SK and Eom YW: 1-Methyl-L-tryptophan promotes the apoptosis of hepatic stellate cells arrested by interferon-γ by increasing the expression of IFN-γRβ, IRF-1 and FAS. Int J Mol Med 40: 576-582, 2017
APA
Oh, J.E., Shim, K.Y., Lee, J.I., Choi, S.I., Baik, S.K., & Eom, Y.W. (2017). 1-Methyl-L-tryptophan promotes the apoptosis of hepatic stellate cells arrested by interferon-γ by increasing the expression of IFN-γRβ, IRF-1 and FAS. International Journal of Molecular Medicine, 40, 576-582. https://doi.org/10.3892/ijmm.2017.3043
MLA
Oh, J. E., Shim, K. Y., Lee, J. I., Choi, S. I., Baik, S. K., Eom, Y. W."1-Methyl-L-tryptophan promotes the apoptosis of hepatic stellate cells arrested by interferon-γ by increasing the expression of IFN-γRβ, IRF-1 and FAS". International Journal of Molecular Medicine 40.2 (2017): 576-582.
Chicago
Oh, J. E., Shim, K. Y., Lee, J. I., Choi, S. I., Baik, S. K., Eom, Y. W."1-Methyl-L-tryptophan promotes the apoptosis of hepatic stellate cells arrested by interferon-γ by increasing the expression of IFN-γRβ, IRF-1 and FAS". International Journal of Molecular Medicine 40, no. 2 (2017): 576-582. https://doi.org/10.3892/ijmm.2017.3043