H₂ O₂ induces oxidative stress damage through the BMP-6/SMAD/hepcidin axis

Area of Science:

• Ophthalmology
• Cell Biology
• Molecular Medicine

Background:

• Age-related macular degeneration (AMD) is a primary cause of vision loss in older adults.
• Oxidative stress in retinal pigment epithelial (RPE) cells is a key factor in AMD development.
• Hepcidin's role in neovascular AMD (nAMD) and its regulation by oxidative stress require further investigation.

Purpose of the Study:

• To investigate the association between Hepcidin and nAMD.
• To determine if oxidative stress inhibits Hepcidin expression via specific signaling pathways.
• To elucidate the mechanism by which oxidative stress contributes to nAMD pathogenesis.

Main Methods:

• Comparison of Hepcidin levels in aqueous humor between nAMD patients and controls.
• In vitro studies using RPE cells treated with hydrogen peroxide (H2O2) to induce oxidative stress.
• Analysis of Hepcidin, Bone morphogenetic protein-6 (BMP-6), intracellular iron, and BMP/SMAD signaling pathway components (smad1, smad5) using PCR, western blotting, and siRNA.

Main Results:

• Hepcidin concentrations were lower in nAMD patients compared to controls.
• H2O2 significantly reduced Hepcidin and BMP-6 expression while increasing intracellular iron in RPE cells.
• BMP-6 reversed H2O2-induced Hepcidin inhibition and iron accumulation, and modulated smad1/smad5 activation, indicating the BMP/SMAD pathway's involvement.

Conclusions:

• Oxidative stress inhibits Hepcidin expression by suppressing the BMP/SMAD signaling pathway in RPE cells.
• Reduced Hepcidin levels due to oxidative stress contribute to the pathogenesis of nAMD.
• These findings provide a foundation for developing novel therapeutic strategies targeting Hepcidin and oxidative stress in nAMD.