Protein inhibitor of activated STAT 4 (PIAS4) regulates liver fibrosis through modulating SMAD3 activity

Abstract

Excessive fibrogenesis disrupts normal liver structure, impairs liver function, and precipitates the development of cirrhosis, an irreversible end-stage liver disease. A host of factors including nutrition surplus contribute to liver fibrosis but the underlying mechanism is not fully understood. In the present study, we investigated the involvement of protein inhibitor for activated stat 4 (PIAS4) in liver fibrosis in a mouse model of non-alcoholic steatohepatitis (NASH). We report that PIAS4 silencing using short hairpin RNA (shRNA) attenuated high-fat high-carbohydrate (HFHC) diet induced liver fibrosis in mice. Quantitative PCR and Western blotting analyses confirmed that PIAS4 knockdown downregulated a panel of pro-fibrogenic genes including type I and type III collagens, smooth muscle actin, and tissue inhibitors of metalloproteinase. Mechanistically, PIAS4 silencing blocked the recruitment of SMAD3, a potent pro-fibrogenic transcription factor, to the promoter regions of pro-fibrogenic genes and dampened SMAD3 acetylation likely by upregulating SIRT1 expression. In conclusion, PIAS4 may contribute to liver fibrosis by modulating SIRT1-dependent SMAD3 acetylation.

Keywords

liver fibrosis / PIAS4 / SMAD3 / acetylation / transcriptional regulation

References

[1] Marchesini G, Petta S, Dalle Grave R. Diet, weight loss, and liver health in nonalcoholic fatty liver disease: Pathophysiology, evidence, and practice[J]. Hepatology, 2015

[2] Argo CK, Northup PG, Al-Osaimi AM, Systematic review of risk factors for fibrosis progression in non-alcoholic steatohepatitis[J]. J Hepatol, 2009, 51(2): 371–379

[3] Tian W, Hao C, Fan Z, Myocardin related transcription factor A programs epigenetic activation of hepatic stellate cells[J]. J Hepatol, 2015, 62(1): 165–174

[4] Fan Z, Hao C, Li M, MKL1 is an epigenetic modulator of TGF-β induced fibrogenesis[J]. Biochim Biophys Acta, 2015, 1849(9): 1219–1228

[5] Tian W, Xu Y. Decoding liver injury: A regulatory role for histone modifications[J]. Int J Biochem Cell Biol, 2015, 67: 188–193

[6] Hernandez-Gea V, Friedman SL. Pathogenesis of liver fibrosis[J]. Annu Rev Pathol, 2011, 6: 425–456

[7] Moustakas A, Souchelnytskyi S, Heldin CH. Smad regulation in TGF-beta signal transduction[J]. J Cell Sci, 2001, 114(Pt 24): 4359–4369

[8] Inoue Y, Itoh Y, Abe K, Smad3 is acetylated by p300/CBP to regulate its transactivation activity[J]. Oncogene, 2007, 26(4): 500–508

[9] Li J, Qu X, Ricardo SD, Resveratrol inhibits renal fibrosis in the obstructed kidney: potential role in deacetylation of Smad3[J]. Am J Pathol, 2010, 177(3): 1065–1071

[10] Sun L, Li H, Chen J, PIASy mediates hypoxia-induced SIRT1 transcriptional repression and epithelial-to-mesenchymal transition in ovarian cancer cells[J]. J Cell Sci, 2013, 126(Pt 17): 3939–3947

[11] Sun L, Li H, Chen J, A SUMOylation-dependent pathway regulates SIRT1 transcription and lung cancer metastasis[J]. J Natl Cancer Inst, 2013, 105(12): 887–898

[12] Kohli R, Kirby M, Xanthakos SA, High-fructose, medium chain trans fat diet induces liver fibrosis and elevates plasma coenzyme Q9 in a novel murine model of obesity and nonalcoholic steatohepatitis[J]. Hepatology, 2010, 52(3): 934–944

[13] Tian W, Xu H, Fang F, Brahma-related gene 1 bridges epigenetic regulation of proinflammatory cytokine production to steatohepatitis in mice[J]. Hepatology, 2013, 58(2): 576–588

[14] Fang F, Chen D, Yu L, Proinflammatory stimuli engage Brahma related gene 1 and Brahma in endothelial injury[J]. Circ Res, 2013, 113(8): 986–996

[15] Kim M, Yi SA, Lee H, Reversine induces multipotency of lineage-committed cells through epigenetic silencing of miR-133a[J]. Biochem Biophys Res Commun, 2014, 445(1): 255–262

[16] Kawai-Kowase K, Ohshima T, Matsui H, PIAS1 mediates TGFbeta-induced SM alpha-actin gene expression through inhibition of KLF4 function-expression by protein sumoylation[J]. Arterioscler Thromb Vasc Biol, 2009, 29(1): 99–106

[17] Netherton SJ, Bonni S. Suppression of TGFβ-induced epithelial-mesenchymal transition like phenotype by a PIAS1 regulated sumoylation pathway in NMuMG epithelial cells[J]. PLoS One, 2010, 5(11): e13971

[18] Lin X, Liang M, Liang YY, Activation of transforming growth factor-beta signaling by SUMO-1 modification of tumor suppressor Smad4/DPC4[J]. J Biol Chem, 2003, 278(21): 18714–18719

[19] Starkel P, Saeger CD, Leclercq I, Horsmans Y. Role of signal transducer and activator of transcription 3 in liver fibrosis progression in chronic hepatitis C-infected patients[J]. Laboratory investigation; a journal of technical methods and pathology. 2007;87(2):173–81. <Date>Epub 2007/02/24</Date>.

[20] Cai Q, Verma SC, Kumar P, Hypoxia inactivates the VHL tumor suppressor through PIASy-mediated SUMO modification[J]. PLoS One, 2010, 5(3): e9720

[21] Byrne CD. Hypoxia and non-alcoholic fatty liver disease[J]. Clin Sci (Lond), 2010, 118(6): 397–400

[22] Mabb AM, Wuerzberger-Davis SM, Miyamoto S. PIASy mediates NEMO sumoylation and NF-kappaB activation in response to genotoxic stress[J]. Nat Cell Biol, 2006, 8(9): 986–993

[23] Lech M, Anders HJ. Macrophages and fibrosis: How resident and infiltrating mononuclear phagocytes orchestrate all phases of tissue injury and repair[J]. Biochim Biophys Acta, 2013, 1832(7): 989–997

Acknowledgements

This work was supported by the Natural Science Foundation of China (No. 81500441). YX is a Fellow at the Collaborative Innovation Center for Cardiovascular Disease Translation Research.

RIGHTS & PERMISSIONS

2016 2016 by the Journal of Biomedical Research. All rights reserved