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Hepatic stellate cell is activated by microRNA-181b via PTEN/Akt pathway

Jianjian Zheng1, Cunzao Wu, Ziqiang Xu

  • 1Wenzhou Key Laboratory of Surgery, The First Affiliated Hospital of Wenzhou Medical University, No. 2 Fuxue Lane, Wenzhou, 325000, Zhejiang, People's Republic of China.

Molecular and Cellular Biochemistry
|August 24, 2014
PubMed

Insights

MicroRNA-181b promotes liver fibrosis by activating hepatic stellate cells (HSCs). It increases alpha-smooth muscle actin and collagen, and activates the PTEN/Akt pathway, driving HSC proliferation and fibrosis progression.

Area of Science:

  • Hepatology
  • Molecular Biology
  • Biochemistry

Background:

  • Hepatic stellate cell (HSC) activation is central to liver fibrosis.
  • MicroRNAs regulate HSC functions, but miR-181b's role in fibrosis is unclear.
  • Previous studies suggested miR-181b promotes HSC proliferation via p27.

Purpose of the Study:

  • To investigate the role of miR-181b in liver fibrosis.
  • To determine if miR-181b affects alpha-smooth muscle actin (α-SMA) and collagen expression in activated HSCs.
  • To elucidate the molecular mechanism of miR-181b in HSC activation.

Main Methods:

  • Measured miR-181b and miR-181a expression in vitro and in vivo models of liver fibrosis.
  • Overexpressed miR-181b in HSCs and assessed α-SMA and type I collagen levels.
  • Identified PTEN as a direct target of miR-181b using luciferase reporter assays.
  • Investigated the effect of miR-181b on the PI3K/Akt pathway and used an Akt inhibitor (LY294002).

Main Results:

  • miR-181b expression was significantly upregulated in activated HSCs and liver fibrosis models.
  • Overexpression of miR-181b increased α-SMA and type I collagen expression and enhanced HSC proliferation.
  • miR-181b directly targets PTEN, suppressing its expression and increasing Akt phosphorylation.
  • Inhibition of Akt signaling blocked the profibrotic effects of miR-181b on HSCs.

Conclusions:

  • miR-181b plays a profibrotic role by activating hepatic stellate cells.
  • miR-181b promotes HSC activation, α-SMA and collagen production, and proliferation.
  • The PTEN/Akt pathway is a key mediator of miR-181b's profibrotic effects in HSCs.

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