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RNA interference targeting ORC1 gene suppresses the proliferation of vascular smooth muscle cells in rats

Mao-qin Shu1, Yue-long Qin, Ming-hong Jiang

  • 1Department of Cardiology, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China. shumaoqin@sina.com.cn

Experimental and Molecular Pathology
|May 24, 2008
PubMed
Abstract

Insights

Silencing the ORC1 gene in vascular smooth muscle cells (VSMCs) halts their proliferation and induces a reversible quiescent state. This suggests ORC1 is a potential therapeutic target for vascular diseases.

Area of Science:

  • Vascular Biology
  • Cell Cycle Regulation
  • Molecular Biology

Background:

  • Vascular smooth muscle cell (VSMC) proliferation is key in vascular diseases like atherosclerosis.
  • The origin recognition complex subunit 1 (ORC1) is crucial for DNA replication initiation in eukaryotes.
  • The role of ORC1 in VSMC DNA replication and proliferation remains uninvestigated.

Purpose of the Study:

  • To investigate the role of ORC1 in VSMC proliferation and apoptosis.
  • To selectively silence the ORC1 gene in rat VSMCs using RNA interference.
  • To analyze the functional consequences of ORC1 gene silencing on VSMC behavior.

Main Methods:

  • Rat VSMCs were transfected with ORC1-targeting siRNA encapsulated in liposomes.
  • ORC1 mRNA and protein levels were quantified using RT-PCR and Western blotting, respectively.
  • DNA synthesis, cell proliferation, cell cycle distribution, and apoptosis-related proteins (Bax, Bcl-2) were assessed.

Main Results:

  • ORC1 gene silencing significantly reduced ORC1 mRNA and protein expression in VSMCs.
  • Silencing ORC1 inhibited DNA synthesis and VSMC proliferation, arresting cells in the G0/G1 phase.
  • ORC1 gene silencing altered the expression of apoptosis-related proteins, suggesting an anti-apoptotic effect.

Conclusions:

  • ORC1 gene silencing induces a reversible quiescent state in VSMCs, halting proliferation.
  • ORC1 plays a critical role in regulating VSMC proliferation.
  • The ORC1 gene represents a promising therapeutic target for suppressing VSMC proliferation in vascular diseases.

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