Taxifolin inhibits NETosis through activation of Nrf2 and provides protective effects in models of lupus and antiphospholipid syndrome.

OBJECTIVES: Taxifolin (dihydroquercetin) is a bioactive plant flavonoid that exhibits anti-inflammatory and anti-oxidative properties. We hypothesized that taxifolin might be an effective dietary supplement to ameliorate symptoms arising from thrombo-inflammatory diseases such as lupus and antiphospholipid syndrome (APS). METHODS: We used in vitro assays and a mouse model to determine mechanisms by which taxifolin inhibits neutrophil extracellular trap (NET) formation (i.e., NETosis) and venous thrombosis in lupus and APS. RESULTS: At doses ranging from 0.1 to 1 µg/ml, taxifolin inhibited NETosis from control neutrophils stimulated with autoantibodies isolated from lupus and APS patients, and its suppressive effects were mitigated by blocking the antioxidant transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). Furthermore, taxifolin at a dose as low as 20 mg/kg/day reduced in vivo NETosis in thrombo-inflammatory mouse models of lupus and APS while also significantly attenuating autoantibody formation, inflammatory cytokine production, and large-vein thrombosis. CONCLUSION: Our study is the first to demonstrate the protective effects of taxifolin in the context of lupus and APS. Importantly, our study also suggests a therapeutic potential to neutralize neutrophil hyperactivity and NETosis that could have relevance to a variety of thrombo-inflammatory diseases.

Ginger intake suppresses neutrophil extracellular trap formation in autoimmune mice and healthy humans.

We previously reported that treatment of mice with 6-gingerol, the most abundant phytochemical in ginger root, leads to phosphodiesterase inhibition that counteracts neutrophil hyperactivity in models of antiphospholipid syndrome (APS) and lupus. Here, we explored the extent to which oral intake of a whole-ginger extract would similarly impact neutrophils in both autoimmune mice and healthy humans. In vitro, a solubilized ginger extract was able to attenuate neutrophil extracellular trap formation (NETosis) by human neutrophils through a mechanism that was dependent upon the cyclic AMP-dependent kinase, protein kinase A. When mice with features of either APS or lupus were administered a ginger extract orally, they demonstrated reduced circulating NETs, as well as the tempering of other disease outcomes, such as large-vein thrombosis (APS) and autoantibody production (lupus). In a pilot clinical trial, which was validated in a second cohort, daily intake of a ginger supplement for 7 days by healthy volunteers boosted neutrophil cAMP, inhibited NETosis in response to disease-relevant stimuli, and reduced circulating plasma NET levels. In summary, this work demonstrates that ginger intake restrains neutrophil hyperactivity in autoimmune mouse models and that ginger consumption by healthy individuals makes their neutrophils more resistant to NETosis.