Oxidative stress, T cell DNA methylation, and lupus

Area of Science:

• Immunology
• Molecular Biology
• Environmental Health

Background:

• Lupus is linked to genetic predisposition and environmental triggers causing oxidative stress.
• Oxidative damage's role in immune system modification leading to lupus flares remains unclear.
• Previous research linked T cell DNA methylation inhibition via ERK pathway signaling to lupus-like autoimmunity.

Purpose of the Study:

• To investigate if oxidizing agents decrease ERK pathway signaling in T cells.
• To determine if oxidizers reduce DNA methyltransferase levels.
• To test if oxidative stress causes DNA demethylation and gene overexpression in T cells, mimicking lupus patient cells.

Main Methods:

• CD4+ T cells were exposed to hydrogen peroxide (H2 O2) or peroxynitrite (ONOO(-)).
• ERK pathway signaling was assessed via immunoblotting.
• DNA methyltransferase 1 (DNMT-1) levels were quantified using RT-PCR.
• Gene methylation and expression were analyzed by flow cytometry, RT-PCR, and bisulfite sequencing.

Main Results:

• Both H2 O2 and ONOO(-) inhibited ERK pathway signaling by affecting protein kinase Cδ.
• Oxidizers decreased DNMT-1 levels in T cells.
• Demethylation and overexpression of specific genes, previously DNA methylation-suppressed, were observed.

Conclusions:

• Oxidative stress can inhibit T cell ERK pathway signaling.
• This inhibition leads to decreased DNMT-1 levels and subsequent DNA demethylation.
• Findings suggest oxidative stress contributes to lupus flares via T cell pathway modulation.