Regio- and Stereoselective Synthesis of Nitro-fatty Acids as NRF2 Pathway Activators Working under Ambient or Hypoxic Conditions.

Nitro-fatty acids (NOFAs) are endogenously produced electrophiles and NRF2 activators with therapeutic potential. We developed a synthetic protocol combining a Henry reaction and base-promoted β-elimination, yielding ultrapure regio/stereoisomers of nitro-stearic (NOSA), nitro-oleic (NOOA), and conjugated/-allylic nitro-linoleic (NOLA) acids. These were tested for NRF2 pathway activation in bone marrow cells under different oxygen conditions. We observed that and , and increased NRF2 stabilization under hypoxia, while and significantly upregulated and at all oxygen levels. and enhanced HO-1 and GCLM proteins independently of oxygen, while was oxygen-dependent, boosting HO-1 under hypoxia and GCLM under ambient conditions. Moreover, and induced NRF2 nuclear translocation. In contrast, the saturated , which has lower electron-acceptor ability, was inactive. In summary, these findings suggest the biological activity of NOFAs is dependent on oxygen level, which could be used in future research of other oxidative stress-dependent pathways.