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Hydrogen peroxide-induced cellular apoptosis is mediated by TGF-beta2 signaling pathway in cultured human lens

Xiaoguang Cao1, Xiaoxin Li, Jianxin Hu

  • 1Department of Ophthalmology, People's Hospital of Peking University, Xizhimen Nan Street No.11, XiCheng District, Beijing, 100044, People's Republic of China. cxgcat@hotmail.com

International Ophthalmology
|May 16, 2009
PubMed

Insights

Hydrogen peroxide induces apoptosis in human lens epithelial cells (HLECs) via the transforming growth factor-beta2 (TGF-beta2) pathway. Neutralizing TGF-beta2 partially protects HLECs from apoptosis by inhibiting Smad-4 translocation and bax gene expression.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Ophthalmology

Background:

  • Hydrogen peroxide (H2O2) is a known inducer of oxidative stress and cellular damage.
  • Cellular apoptosis, or programmed cell death, is a critical process implicated in various diseases, including those affecting the eye.
  • The transforming growth factor-beta2 (TGF-beta2) signaling pathway, involving Smad proteins, plays a role in cellular regulation and apoptosis.

Purpose of the Study:

  • To investigate the role of the TGF-beta2/Smad signaling pathway in H2O2-induced apoptosis of human lens epithelial cells (HLECs).
  • To determine if blocking TGF-beta2 signaling can protect HLECs from H2O2-induced apoptosis.

Main Methods:

  • Human lens epithelial cells (HLECs) were exposed to H2O2 with or without a TGF-beta2 neutralization antibody (AF-302-NA).
  • Apoptosis was assessed using TUNEL and Annexin V-FITC flow cytometry.
  • Gene expression of TGF-beta receptors (TbetaRs) and the apoptotic gene bax was analyzed by RT-PCR.
  • Smad-4 localization was determined by immunocytochemistry.

Main Results:

  • H2O2 induced HLEC apoptosis, characterized by Smad-4 nuclear translocation and upregulation of bax gene expression.
  • AF-302-NA significantly reduced H2O2-induced HLEC apoptosis.
  • The antibody inhibited Smad-4 nuclear translocation and modulated the expression of TbetaRs and bax mRNA.

Conclusions:

  • The TGF-beta2 signaling pathway is involved in H2O2-induced apoptosis in HLECs.
  • Blocking TGF-beta2 signaling offers partial protection to HLECs against H2O2-induced apoptosis.
  • Targeting the TGF-beta2 pathway may be a potential therapeutic strategy for conditions involving oxidative stress-induced lens cell damage.

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