Nitro-Fatty Acid irreversible inhibition of PTP-1B.

REYES, AB; VAZQUEZ M; SUBIRADA P; SANCHEZ MC; BONACCI G

Mar del Plata, Buenos Aires

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2015

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Insulin signaling impairment is associated with type II diabetes and obesity. This molecular pathway is tightly regulated by protein kinases and protein phosphatases activity. Lack of PTP1B activity improves insulin sensitivity and blood glucose levels. PTP1B enclose a cysteine in the catalytic domain which turns out an important modulator of its activity by reactive oxygen species (ROS). Recently, we have shown that systemic nitro-oleic acid (NO2-OA)administration reduces insulin resistance in a diabetic (ob/ob) mouse model and increases glucose uptake. Nitro-fatty acid derived activates, in part, PPARγ dependent gene expression. However, the thiol reactivity of NO2-OA appears to play a crucial role in modulate insulin sensitivity by inhibited PTP1B activity. Our results demonstrated that enzyme activity was dose dependent and irreversible inhibited by NO2-OA as shown by GSH and BME competition. Furthermore, mass spectrometry analysis revealed NO2-OA covalent adducted to different nucleophile residue on PTP1B, including the cysteine 215. In addition, extended insulin phosphorilation of AKT, and MAPK in 3T3-L1 cell pretreated with NO2-OA compared with untreated cells. Thus, we have characterized the inhibition of PTP1B by nitro-alkylation of cys-215, a mechanism that suggests the participation of NO2-FA in the insulin signaling pathway via PPARγ independent manner.