Effects of valerate on intestinal barrier function in cultured Caco-2 epithelial cell monolayers

• Published in: Molecular biology reports Vol. 49; no. 3; pp. 1817 - 1825
• Main Authors: Gao, Guanzhen, Zhou, Jingru, Wang, Huiqin, Ding, Yanan, Zhou, Jianwu, Chong, Pik Han, Zhu, Liying, Ke, Lijing, Wang, Xin, Rao, Pingfan, Wang, Qiang, Zhang, Longxin
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2022; Springer Nature B.V
• Subjects: Amino acids; Animal Anatomy; Animal Biochemistry; Biomedical and Life Sciences; butyrates; Caco-2 Cells; colon; dietary fiber; electrical resistance; Electrical resistivity; Epithelial cells; Epithelial Cells - metabolism; Fatty acids; Histology; Homeostasis; human cell lines; Humans; Intestinal Mucosa - metabolism; Intestine; Life Sciences; metabolites; molecular biology; Morphology; Original Article; Permeability; Tight junctions; Tight Junctions - metabolism; Valerates - metabolism; Valerates - pharmacology; Western blotting; Valerate; Caco-2 cell monolayer; AMPK activation; Intestinal barrier function; Tight junction assembly
• ISSN: 0301-4851; 1573-4978; 1573-4978
• DOI: 10.1007/s11033-021-06991-w

Background Short-chain fatty acids (SCFAs) are a group of microbial metabolites of undigested dietary fiber, protein and unabsorbed amino acids in the colon, well-known for their gut health promoting benefits. A relatively high intestinal level of valerate was found in the healthy human subjects. However, the intestinal protection effects and the underlying mechanism of valerate are waiting to be verified and elucidated. Methods and Results In the present study, valerate, a SCFAs mainly converted from proteins or amino acids, was demonstrated to promote intestinal barrier function at its physiological concentrations of 0–4 mM in the Caco-2 cell monolayer model of intestinal barrier using transepithelial electrical resistance (TEER) assay and paracellular permeability assay. Valerate achieved the maximum increase in the TEER at 2 mM and reduced the paracellular permeability. Its intestinal barrier function promoting activity is similar to that of butyrate, with a broader range of effective concentrations than the later. Through western blot analysis, this activity is linked to the valerate-induced AMPK activation and tight junctions (TJs) assembly, but not to the reinforced expression of TJs related proteins. Conclusions It provides direct experimental evidence supporting valerate’s function in intestinal health, implying the once under-valued function of valerate and its amino acid precursors. The valerate’s role in regulating intestine homeostasis and its possible synergetic effects with other SCFAs warranted to be further investigated.