Ameliorative effects of phosphorylated peptide from Antarctic krill (Euphausia superba) against H2O2-induced damage in MC3T3-E1 cells

Abstract Phosphorylated peptide from Antarctic krill (P-AKP) was prepared by the dry-heating method with sodium pyrophosphate in order to improve its antioxidant activity and osteogenic activity. P-AKP exhibited more competitive DPPH• and OH• scavenging activities compared to the native Antarctic krill peptide (AKP). In hydrogen peroxide (H2O2)-induced oxidative damage of MC3T3-E1 cells, both AKP and P-AKP pretreatment could dose-dependently improve superoxide dismutase (SOD) and catalase (CAT) activities through attenuating the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) production. Moreover, AKP and P-AKP prevented oxidative stress-induced down regulation of alkaline phosphatase (ALP) activity and matrix mineralization. Particularly, the promoting effects of P-AKP on the enzymatic antioxidant defense system, differentiation and mineralization was higher than that of AKP. These results suggested that phosphorylation might be a promising approach to improve the antioxidant and osteogenic activity of AKP, and P-AKP could be a beneficial agent for attenuating oxidative stress-related bone loss.

摘要：本研究以焦磷酸钠为磷酸化试剂，采用干热法制备南极磷虾源磷酸化肽（P-AKP，Phosphorylated peptide from Antarctic krill），以提升天然南极磷虾肽（AKP，native Antarctic krill peptide）的抗氧化与成骨活性。相较于天然南极磷虾肽（AKP），P-AKP对1,1-二苯基-2-三硝基苯肼自由基（1,1-diphenyl-2-picrylhydrazyl radical, DPPH•）与羟自由基（hydroxyl radical, OH•）的清除活性更具优势。在过氧化氢（hydrogen peroxide, H₂O₂）诱导的小鼠成骨细胞MC3T3-E1氧化损伤模型中，AKP与P-AKP预处理均可通过抑制活性氧（reactive oxygen species, ROS）积累与丙二醛（malondialdehyde, MDA）生成，剂量依赖性提升超氧化物歧化酶（superoxide dismutase, SOD）与过氧化氢酶（catalase, CAT）活性。此外，AKP与P-AKP均可逆转氧化应激（oxidative stress）介导的碱性磷酸酶（alkaline phosphatase, ALP）活性下调及基质矿化（matrix mineralization）抑制。尤为关键的是，P-AKP对酶促抗氧化防御系统（enzymatic antioxidant defense system）、细胞分化及基质矿化的促进效果显著优于AKP。上述结果表明，磷酸化修饰可作为改善AKP抗氧化与成骨活性的有效手段，P-AKP有望成为缓解氧化应激相关骨丢失的潜在功能性制剂。