Activation of murine RAW264.7 macrophages by oligopeptides from sea cucumber (Apostichopus japonicus) and its molecular mechanisms
Nan Cai, Wenqi Luo, Lijun Yao, Xiuting Li, Zuzhe Wang, Hong Xu, Hui Li, Zhangli Hu, Wei-Yang Bao, Xu Xu
Abstract
Sea cucumbers are valuable marine foods as well as a source of traditional medicines with various bioactivities. Macrophage activation by small-molecule oligopeptides obtained from the sea cucumber Apostichopus japonicus (SCOP) were investigated. After SCOP were proven nontoxic by oral administration and CCK-8 assays, we measured immune-stimulatory mRNA, pro-inflammatory cytokines, and NO production levels and determined the molecular mechanism of macrophage stimulation. Our results demonstrated that SCOP upregulated both the mRNA levels and the secretion of NO, TNF-α, and IL-6 in a dose-dependent manner. More importantly, SCOP contributed to the stimulation of macrophages through the upregulation of the NF-κB and MAPK signaling pathways. Taken together, these results indicated that SCOP exerted macrophage activation effects on RAW264.7 cells and that they could potentially be used as a functional food supplement in treating immune suppression.