A FABP4-PPARγ signaling axis regulates human monocyte responses to electrophilic fatty acid nitroalkenes

Lamas Bervejillo, María - Bonanata, Jenner - Franchini, G. R. - Richeri Corral, Analía - Marqués, Juan Martín - Freeman, B.A. - Schopfer, F.J. - Coitiño, Laura E. - Córsico, B. - Rubbo, Homero - Ferreira, Ana María

Resumen:

Nitro-fatty acids (NO2-FA) are electrophilic lipid mediators derived from unsaturated fatty acid nitration. These species are produced endogenously by metabolic and inflammatory reactions and mediate anti-oxidative and anti-inflammatory responses. NO2-FA have been postulated as partial agonists of the Peroxisome Proliferator- Activated Receptor gamma (PPARγ), which is predominantly expressed in adipocytes and myeloid cells. Herein, we explored molecular and cellular events associated with PPARγ activation by NO2-FA in monocytes and macrophages. NO2-FA induced the expression of two PPARγ reporter genes, Fatty Acid Binding Protein 4 (FABP4) and the scavenger receptor CD36, at early stages of monocyte differentiation into macrophages. These responses were inhibited by the specific PPARγ inhibitor GW9662. Attenuated NO2-FA effects on PPARγ sig- naling were observed once cells were differentiated into macrophages, with a significant but lower FABP4 up- regulation, and no induction of CD36. Using in vitro and in silico approaches, we demonstrated that NO2-FA bind to FABP4. Furthermore, the inhibition of monocyte FA binding by FABP4 diminished NO2-FA-induced upre- gulation of reporter genes that are transcriptionally regulated by PPARγ, Keap1/Nrf2 and HSF1, indicating that FABP4 inhibition mitigates NO2-FA signaling actions. Overall, our results affirm that NO2-FA activate PPARγ in monocytes and upregulate FABP4 expression, thus promoting a positive amplification loop for the downstream signaling actions of this mediator.


Detalles Bibliográficos
2020
Nitro-fatty acids
Peroxisome proliferator-activated receptor gamma
Fatty acid binding protein 4
Monocytes
Macrophages
Lipid signaling
Inglés
Universidad de la República
COLIBRI
https://hdl.handle.net/20.500.12008/30855
Acceso abierto
Licencia Creative Commons Atribución (CC - By 4.0)