Bradykinin-potentiating PEPTIDE-10C, an argininosuccinate synthetase activator, protects against H2O2-induced oxidative stress in SH-SY5Y neuroblastoma cells

Bradykinin-potentiating peptides (BPPs - 5a, 7a, 9a, 10c, 11e, and 12b) of Bothrops jararaca (Bj) were described as argininosuccinate synthase (AsS) activators, improving L-arginine availability. Agmatine and polyamines, which are L-arginine metabolism products, have neuroprotective properties. Here, we investigated the neuroprotective effects of low molecular mass fraction from Bj venom (LMMF) and two synthetic BPPs (BPP-10c, < ENWPHPQIPP; BPP-12b,< EWGRPPGPPIPP) in the SH-SY5Y cell line against H2O2-induced oxidative stress. The neuroprotective effects against H2O2-induced were analyzed by reactive oxygen species (ROS - DCFH) production; lipid peroxidation (TBARS); intracellular GSH; AsS, iNOS, and NF-kB expressions; nitrite levels (Griess); mitochondrial membrane potential (TMRM); and antioxidant activity (DPPH). Analysis of variance followed by Tukey's post hoc test were calculated for statistical comparisons. Pre-treatment with both BPPs significantly reduced cell death induced by H2O2, but BPP-10c showed higher protective capacity than BPP-12b. LMMF pretreatment was unable to prevent the reduction of cell viability caused by H2O2. The neuroprotective mechanism of BPP-10c against oxidative stress was investigated. BPP-10c reduced ROS generation and lipid peroxidation in relation to cells treated only with H2O2. BBP-10c increased AsS expression and was not neuroprotective in the presence of MDLA, a specific inhibitor of AsS. BPP-10c reduced iNOS expression and nitrate levels but decreased NF-kB expression. Furthermore, BPP-10c protected the mitochondrial membrane against oxidation. Overall, we demonstrated for the first time neuroprotective mechanisms of BPPs against oxidative stress, opening new perspectives to the study and application of these peptides for the treatment of neurode-generative diseases.