Exogenous Hydrogen Peroxide Induces Lipid Raft-Mediated STAT-6 Activation in T Cells

Abstract

Background/Aims: CD4+ T cells are a critical component of the adaptive immune response. While the mechanisms controlling the differentiation of the Th1, Th17, and regulatory T cell subsets from naïve CD4+ T cells are well described, the factors that induce Th2 differentiation are still largely unknown. Methods: The effects of treatment with exogenous H₂O₂ on STAT-6 phosphorylation and activation in T cells were examined by immunoblotting, immunofluorescence and gel shift assay. Anti-CD3 antibody and methyl-β-cyclodextrin were utilized to induce lipid raft assembly and to investigate the involvement of lipid rafts, respectively. Results: Jurkat and EL-4 T cells that were exposed to H₂O₂ showed rapid and strong STAT-6 phosphorylation, and the extent of STAT-6 phosphorylation was enhanced by co-treatment with anti-CD3 antibody. The effect of H₂O₂ on STAT-6 phosphorylation and translocation was inhibited by disruption of lipid rafts. STAT-6 activation in response to H₂O₂ treatment regulated IL-4 gene expression, and this response was strengthened by treatment with anti-CD3. Conclusion: Our results indicate that reactive oxygen species such as H₂O₂ can act on upstream and initiating factors for activation of STAT-6 in T cells and contribute to formation of a positive feedback loop between STAT-6 and IL-4 in the Th2 differentiation process.

Implication of oxidative stress in the pathogenesis of systemic sclerosis via inflammation, autoimmunity and fibrosis

“…Oxidative stress is important for macrophage polarization, especially for M2 differentiation that is blocked by an inhibition of superoxide production [22]. Interestingly, STAT6 was shown to be involved in M2 macrophage polarization [23], and can be activated by ROS in T cells [24]. Thus it can be hypothesized that ROS may be responsible for the M2 polarization via STAT6 induction in SSc.…”

Extracellular Delivery of Functional Mitochondria Rescues the Dysfunction of CD4+ T Cells in Aging

“…[ 9 , 13 , 16 ] Due to its permeability, H 2 O 2 serves as a secondary messenger molecule. [ 16 , 17 , 99 , 100 ] For instance, exposed thiol moieties (‐SH) on proteins can be oxidized by H 2 O 2 , altering protein conformation to favor either increases or decreases in enzymatic activities. [ 18 , 19 ] Concurrently, mitoROS contribute to the formation of other increasingly destructive ROS.…”

MicroRNA-125a-Loaded Polymeric Nanoparticles Alleviate Systemic Lupus Erythematosus by Restoring Effector/Regulatory T Cells Balance

“…During the activation, T cells have increased clathrin-mediated endocytosis to fine-tune the TCR signaling strength and engage in macropinocytosis to access of extracellular amino acid for cell growth . The special cellular uptake inhibitors (PitStop, inhibitor of clathrin-mediated endocytosis; EIPA, inhibitor of macropinocytosis; MβCD, inhibitor of clathrin-independent endocytosis , ) were used to further explore the mechanism of PEAL NPs cellular uptake pathway. The uptake of PEAL NPs by rested and activated T cells was significantly blocked by PitStop compared to other inhibitors, which showed that the uptake of PEAL NPs was mainly mediated by clathrin-mediated endocytosis (Supporting Figure 4).…”

“…Inhibitor was added into medium 15 min prior to addition of PEAL NPs. Final concentrations of inhibitors are as follows: 25 μM PitStop 2, 50 μM EIPA, or 2.5 mM MβCD (Sigma-Aldrich). , Then the rested or the activated T cells were co-cultured with PEAL cy5‑miNC NPs for 6 h before the cells were collected for measurement.…”