O-GlcNAcylation mediates H₂O₂-induced apoptosis through regulation of STAT3 and FOXO1

Area of Science:

• Biochemistry
• Cell Biology
• Neuroscience

Background:

• O-linked β-N-acetylglucosamine (O-GlcNAc) glycosylation is a dynamic post-translational modification crucial for cellular signaling.
• The role of O-GlcNAcylation in oxidative stress-induced apoptosis, particularly identifying specific protein targets, remains largely unexplored.

Purpose of the Study:

• To investigate the involvement of O-GlcNAcylation in hydrogen peroxide (H2O2)-induced apoptosis in neuroblastoma N2a cells.
• To identify critical protein targets of O-GlcNAcylation that mediate apoptosis under oxidative stress.

Main Methods:

• Treatment of N2a cells with H2O2, O-GlcNAc transferase (OGT) inhibitor (OSMI-1), and O-GlcNAcase (OGA) inhibitor (Thiamet-G).
• Assessment of cell viability, apoptosis markers (cleaved caspase 3), and protein levels/activity of STAT3 and FOXO1.
• Manipulation of OGT/OGA activity and STAT3/FOXO1 expression/activity to determine their roles in apoptosis.

Main Results:

• H2O2 treatment inhibited O-GlcNAcylation, reduced cell viability, and promoted apoptosis in N2a cells.
• OSMI-1 enhanced H2O2-induced apoptosis, while Thiamet-G inhibited it.
• STAT3 and FOXO1 were identified as key targets; their modulation affected apoptosis, with STAT3 and FOXO1 overexpression protecting against OSMI-1-induced apoptosis, and their downregulation abolishing the anti-apoptotic effects of OGT and Thiamet-G.

Conclusions:

• O-GlcNAcylation plays a significant role in regulating oxidative stress-induced apoptosis in neuroblastoma cells.
• STAT3 and FOXO1 are identified as direct or indirect targets of O-GlcNAcylation involved in this process.
• Modulating O-GlcNAcylation pathways offers a potential therapeutic strategy for neuroprotection against oxidative stress.