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Live Cell Imaging of the TGF- β/Smad3 Signaling Pathway In Vitro and In Vivo Using an Adenovirus Reporter System
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Reversible phospho-Smad3 signalling between tumour suppression and fibrocarcinogenesis in chronic hepatitis B

Y-R Deng1, K Yoshida, Q L Jin

  • 1Liver Immunology Laboratory, Institute of Immunology and School of Life Sciences, University of Science and Technology of China, Hefei, China; Intensive Care Unit, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China.

Clinical and Experimental Immunology
|December 31, 2013
PubMed

Insights

Hepatitis B virus infection alters Smad3 protein phosphorylation, promoting liver fibrosis and cancer. Nucleoside analogue therapy reverses this, restoring protective Smad3 signaling and suppressing disease progression.

Area of Science:

  • Hepatology
  • Molecular Biology
  • Virology

Background:

  • Transforming growth factor-beta (TGF-β) signaling, mediated by Smad3 phosphorylation, plays a critical role in liver fibrosis and hepatocellular carcinoma (HCC).
  • Two distinct Smad3 isoforms, phosphorylated at the COOH-terminus (pSmad3C) and linker region (pSmad3L), differentially regulate hepatocytic fibrogenesis.
  • The impact of hepatitis B virus (HBV) infection on these Smad3 isoforms and the effect of antiviral therapy remain incompletely understood.

Purpose of the Study:

  • To compare the effects of HBV infection on hepatocytic Smad3 phosphorylated isoforms before and after antiviral therapy.
  • To elucidate the relationship between Smad3 phosphorylation patterns and the progression of liver disease in HBV patients.
  • To assess the efficacy of nucleoside analogue therapy in modulating Smad3 signaling pathways.

Main Methods:

  • Study included patients with HBV-related fibrotic liver disease (stages F1-F4) and HBV-associated HCC.
  • Analyzed paired liver biopsies from 27 chronic hepatitis B patients before and after 52 weeks of nucleoside analogue treatment (Lamivudine or Telbivudine).
  • Compared fibrosis stage, inflammatory activity, and hepatocytic phosphorylated Smad3 (pSmad3C and pSmad3L) positivity.

Main Results:

  • Hepatocytic pSmad3C signaling shifted towards fibrocarcinogenic pSmad3L signaling as liver disease progressed from chronic hepatitis B to HCC.
  • Nucleoside analogue treatment significantly decreased serum alanine aminotransferase (ALT) and HBV-DNA levels.
  • Antiviral therapy restored pSmad3C signaling in hepatocytes and reduced pSmad3L signaling, correlating with decreased viral load.

Conclusions:

  • Oral nucleoside analogue therapies effectively suppress liver fibrosis and reduce HCC incidence in chronic hepatitis B patients.
  • Therapy achieves this by reversing detrimental Smad3 phosphorylation patterns, restoring protective pSmad3C signaling and diminishing pro-fibrotic pSmad3L signaling.
  • These findings highlight the therapeutic potential of targeting Smad3 signaling in managing HBV-related liver disease, even in advanced stages like cirrhosis.
Keywords:
HBVTGF-βpSmadCpSmadL

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