Sulforaphane Inhibits Inflammatory Responses of Primary Human T-Cells by Increasing ROS and Depleting Glutathione

Abstract

The activity and function of T-cells are influenced by the intra- and extracellular redox milieu. Oxidative stress induces hypo responsiveness of untransformed T-cells. Vice versa increased glutathione (GSH) levels or decreased levels of reactive oxygen species (ROS) prime T-cell metabolism for inflammation, e.g., in rheumatoid arthritis. Therefore, balancing the T-cell redox milieu may represent a promising new option for therapeutic immune modulation. Here we show that sulforaphane (SFN), a compound derived from plants of the Brassicaceae family, e.g., broccoli, induces a pro-oxidative state in untransformed human T-cells of healthy donors or RA patients. This manifested as an increase of intracellular ROS and a marked decrease of GSH. Consistently, increased global cysteine sulfenylation was detected. Importantly, a major target for SFN-mediated protein oxidation was STAT3, a transcription factor involved in the regulation of TH17-related genes. Accordingly, SFN significantly inhibited the activation of untransformed human T-cells derived from healthy donors or RA patients, and downregulated the expression of the transcription factor RORγt, and the TH17-related cytokines IL-17A, IL-17F, and IL-22, which play a major role within the pathophysiology of many chronic inflammatory/autoimmune diseases. The inhibitory effects of SFN could be abolished by exogenously supplied GSH and by the GSH replenishing antioxidant N-acetylcysteine (NAC). Together, our study provides mechanistic insights into the mode of action of the natural substance SFN. It specifically exerts TH17 prone immunosuppressive effects on untransformed human T-cells by decreasing GSH and accumulation of ROS. Thus, SFN may offer novel clinical options for the treatment of TH17 related chronic inflammatory/autoimmune diseases such as rheumatoid arthritis.

Naturally Derived Heme-Oxygenase 1 Inducers and Their Therapeutic Application to Immune-Mediated Diseases

“…The beneficial effect of SFN-induced Nrf2-HO-1/NQO-1 signaling pathway activation was also demonstrated in chronic renal allograft dysfunction (Figure 1) (218). Furthermore, SFN suppresses T H 17 response on untransformed human T cells by decreasing GSH and the accumulation of ROS (219). Interestingly, SFN also inhibits the inflammatory response by suppressing the cytokines response, NFκB activation, and inducing HO-1 expression in cultured monocytes and the lungs of mice (220).…”

Piperlongumine Acts as an Immunosuppressant by Exerting Prooxidative Effects in Human T Cells Resulting in Diminished TH17 but Enhanced Treg Differentiation

“…ROS detection reagent CM-H 2 DCFDA was used for the measurement of intracellular ROS levels and ThiolTracker TM violet dye was used for the measurement of intracellular GSH levels as described before (30). Briefly, for the intracellular ROS measurement, T cells (1 × 10 6 cells/ml) or Jurkat cells (3 × 10 5 cells/ml) were washed with PBS and stained with CM-H 2 DCFDA (5 µM) in PBS for 15 min at 37 • C. Cells were then washed with PBS, resuspended in RPMI complete medium and treated with DMSO, PL or H 2 O 2 .…”

“…Afterwards, the cells were seeded on a 96-well microplate coated with anti-CD3/CD28 antibodies and incubated for 72 h. The CFSE signal was determined using flow cytometry and data were analyzed with FlowJo X. The proliferation index was calculated as described previously (30).…”

“…The gene expression profiling was performed with 25 ng total RNA per sample and all RNA samples were analyzed using the Nanostring nCounter GX Human Immunology v2 kit. The gene expression profiling and data analyses were performed as previously described (30). Briefly, the hybridization reaction was carried out at 65 • C overnight by mixing RNA samples with nCounter reporter probes and capture probes in hybridization buffer.…”

Perspective on dietary isothiocyanates in the prevention, development and treatment of cancer

“…In this regard advice has yet to emerge on an appropriate diet that could accurately provide the necessary dietary phytochemicals that might prove most effective in blocking cancer initiation and progression and are intrinsically anti-inflammatory [94][95][96][97] . Many phytochemicals possess these properties and a routine intake of the right combinations of phytochemicals that would include the ITCs, well recognized for their anti-inflammatory activity, might fit the bill.…”