Oyster Peptides Prepared by Lactobacillus casei Fermentation Enhance Immune Activity in RAW264.7 Cells via Activation of the MAPK Pathway.

2025-12-18
Marine drugs 23(12)

PubMed: 41440918
DOI: 10.3390/md23120484

Study Design

Methods: oyster proteins were fermented using Lactobacillus casei to prepare bioactive peptides; fermentation parameters (time, temperature, and inoculum amount) were optimized; in vitro immunological evaluation using RAW264.7 macrophages

Animal Study

Oyster peptides (OPs) have gained increasing attention for their excellent biological activities, especially immunomodulatory effects. In this study, oyster proteins were fermented using Lactobacillus casei to prepare bioactive peptides, and the effects of fermentation parameters (time, temperature, and inoculum amount) on the degree of hydrolysis (DH) were optimized. The optimal fermentation conditions were determined as 30 h, 35 °C, and 5% inoculum amount, resulting in a DH of 28.24%. Structural characterization showed that OPs were mainly composed of low-molecular-weight peptides (<1000 Da) with high hydrophobic amino acid content, and they exhibited good stability during in vitro gastrointestinal digestion. In vitro immunological evaluation using RAW264.7 macrophages demonstrated that OPs significantly enhanced phagocytic activity and nitric oxide (NO) production, and upregulated the mRNA expression levels of pro-inflammatory cytokines including interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α. Mechanistically, OPs exerted immunostimulatory effects by specifically activating the extracellular signal-regulated kinase (ERK) pathway within the mitogen-activated protein kinase (MAPK) signaling cascade, without significant alterations in the phosphorylation levels of p38 and c-Jun N-terminal kinase (JNK). These findings highlight the potential of Lactobacillus casei-fermented oyster peptides as natural immunomodulatory ingredients for functional food development.

Research Insights

Supplement	Dose	Health Outcome	Effect Type	Effect Size	Source
Lactobacillus casei Lc-11	—	Improved Immune Function	Beneficial	Moderate	View source OPs significantly enhanced phagocytic activity and nitric oxide (NO) production, and upregulated the mRNA expression levels of pro-inflammatory cytokines including interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α.