TY - JOUR
T1 - p300 Acetyltransferase Is a Cytoplasm-to-Nucleus Shuttle for SMAD2/3 and TAZ Nuclear Transport in Transforming Growth Factor β–Stimulated Hepatic Stellate Cells
AU - Wang, Yuanguo
AU - Tu, Kangsheng
AU - Liu, Donglian
AU - Guo, Luyang
AU - Chen, Yunru
AU - Li, Qing
AU - Maiers, Jessica L.
AU - Liu, Zhikui
AU - Shah, Vijay H.
AU - Dou, Changwei
AU - Tschumperlin, Daniel
AU - Voneschen, Luke
AU - Yang, Rendong
AU - Kang, Ningling
N1 - Publisher Copyright:
© 2019 The Authors. Hepatology published by Wiley Periodicals, Inc., on behalf of American Association for the Study of Liver Diseases.
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Nuclear translocation of mothers against decapentaplegic homolog 2/3 (SMAD2/3), core transcription factors of transforming growth factor β (TGF-β) signaling, is critical for hepatic stellate cell (HSC) differentiation into metastasis-promoting myofibroblasts. SMAD2/3 have multiple coactivators, including WW domain-containing transcription regulator protein 1 (WWTR1 or TAZ) and p300 acetyltransferase. In the nucleus, TAZ binds to SMAD2/3 to prevent SMAD2/3 nuclear export. However, how TAZ and SMAD2/3 enter the nucleus remains poorly understood because neither contains a nuclear localization signal (NLS), an amino acid sequence tagging proteins for nuclear transport. p300 is an NLS-containing large scaffold protein, so we hypothesized that SMAD2/3 and TAZ may undergo nuclear import through complexing with p300. Coimmunoprecipitation, immunofluorescence, and nuclear fractionation assays revealed that TGF-β1 promoted binding of SMAD2/3 and TAZ to p300 and that p300 inactivation disrupted TGF-β1-mediated SMAD2/3 and TAZ nuclear accumulation. Deleting the p300 NLS blocked TGF-β1-induced SMAD2/3 and TAZ nuclear transport. Consistently, p300 inactivation suppressed TGF-β1-mediated HSC activation and transcription of genes encoding tumor-promoting factors, such as connective tissue growth factor, Tenascin C, Periostin, platelet-derived growth factor C, and fibroblast growth factor 2, as revealed by microarray analysis. Chromatin immunoprecipitation-real-time quantitative PCR showed that canonical p300-mediated acetylation of histones also facilitated transcription in response to TGF-β1 stimulation. Interestingly, although both TGF-β1-mediated and stiffness-mediated HSC activation require p300, comparison of gene expression data sets revealed that transcriptional targets of TGF-β1 were distinct from those of stiffness-p300 mechanosignaling. Lastly, in tumor/HSC coinjection and intrasplenic tumor injection models, targeting p300 of activated-HSC/myofibroblasts by C646, short hairpin RNA, or cre-mediated gene disruption reduced tumor and liver metastatic growth in mice. Conclusion: p300 facilitates TGF-β1-stimulated HSC activation by both noncanonical (cytoplasm-to-nucleus shuttle for SMAD2/3 and TAZ) and canonical (histone acetylation) mechanisms. p300 is an attractive target for inhibiting HSC activation and the prometastatic liver microenvironment.
AB - Nuclear translocation of mothers against decapentaplegic homolog 2/3 (SMAD2/3), core transcription factors of transforming growth factor β (TGF-β) signaling, is critical for hepatic stellate cell (HSC) differentiation into metastasis-promoting myofibroblasts. SMAD2/3 have multiple coactivators, including WW domain-containing transcription regulator protein 1 (WWTR1 or TAZ) and p300 acetyltransferase. In the nucleus, TAZ binds to SMAD2/3 to prevent SMAD2/3 nuclear export. However, how TAZ and SMAD2/3 enter the nucleus remains poorly understood because neither contains a nuclear localization signal (NLS), an amino acid sequence tagging proteins for nuclear transport. p300 is an NLS-containing large scaffold protein, so we hypothesized that SMAD2/3 and TAZ may undergo nuclear import through complexing with p300. Coimmunoprecipitation, immunofluorescence, and nuclear fractionation assays revealed that TGF-β1 promoted binding of SMAD2/3 and TAZ to p300 and that p300 inactivation disrupted TGF-β1-mediated SMAD2/3 and TAZ nuclear accumulation. Deleting the p300 NLS blocked TGF-β1-induced SMAD2/3 and TAZ nuclear transport. Consistently, p300 inactivation suppressed TGF-β1-mediated HSC activation and transcription of genes encoding tumor-promoting factors, such as connective tissue growth factor, Tenascin C, Periostin, platelet-derived growth factor C, and fibroblast growth factor 2, as revealed by microarray analysis. Chromatin immunoprecipitation-real-time quantitative PCR showed that canonical p300-mediated acetylation of histones also facilitated transcription in response to TGF-β1 stimulation. Interestingly, although both TGF-β1-mediated and stiffness-mediated HSC activation require p300, comparison of gene expression data sets revealed that transcriptional targets of TGF-β1 were distinct from those of stiffness-p300 mechanosignaling. Lastly, in tumor/HSC coinjection and intrasplenic tumor injection models, targeting p300 of activated-HSC/myofibroblasts by C646, short hairpin RNA, or cre-mediated gene disruption reduced tumor and liver metastatic growth in mice. Conclusion: p300 facilitates TGF-β1-stimulated HSC activation by both noncanonical (cytoplasm-to-nucleus shuttle for SMAD2/3 and TAZ) and canonical (histone acetylation) mechanisms. p300 is an attractive target for inhibiting HSC activation and the prometastatic liver microenvironment.
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U2 - 10.1002/hep.30668
DO - 10.1002/hep.30668
M3 - Article
C2 - 31004519
AN - SCOPUS:85072230879
SN - 0270-9139
VL - 70
SP - 1409
EP - 1423
JO - Hepatology
JF - Hepatology
IS - 4
ER -