Anti-Inflammatory and Transepithelial Transport Activities of Rapeseed (Brassica napus) Napin-Derived Dipeptide Thr-Leu in Caco-2 and RAW264.7 Cocultures

作者：Zhang, Jing; Yao, Yijun; Xu, Feiran; Yuan, Qiang; Ju, Xingrong; Wang, Lifeng^*

来源：Journal of Agricultural and Food Chemistry, 2023, 71(22): 8437-8447.

DOI：10.1021/acs.jafc.3c00227

• dipeptide Thr-Leu
• coculture model
• anti-inflammatory
• Caco-2 cell monolayers
• RAW264
• 7 macrophage cells

This study aimed to investigate the anti-inflammatorymolecularactivity of rapeseed napin-derived dipeptide Thr-Leu (TL) using Caco-2/RAW264.7cell cocultures. This in vitro coculture intestinal inflammation modelwas used to assess the absorption, evolution, and anti-inflammatoryeffects of peptides. TL was absorbed by the intestinal epithelialcells with an apparent permeability of (2.48 +/- 0.18) x 10(-6) cm/s, primarily through the PepT1 pathway. TL treatmentexerted anti-inflammatory and restorative effects on the impairedintestinal barrier function by enhancing the expression levels ofoccludin and ZO-1 in lipopolysaccharide (LPS)-induced Caco-2 cells.No significant change (P < 0.05) was detectedin claudin-1 expression levels; however, the occludin expression levelswere upregulated through the protein kinase C (PKC) signaling pathway.Compared with the LPS-induced group, TL (2.0 mM) reduced the levelsof intracellular inflammation-related enzymes (iNOS: by 50.84%; COX-2:by 49.64%) on the coculture cell model. In addition, the interleukin(IL)-1 beta, IL-6, and TNF-alpha levels in RAW264.7 cells weresignificantly (P < 0.05) downregulated followingTL treatment (2.0 mM) due to the suppression of the phosphorylationof the JNK-independent pathway on the basolateral side of the coculturecell model. These findings highlight the potential use of TL in functionalfoods or nutraceuticals to prevent intestinal inflammation.