Objective: The short-chain fatty acids (SCFAs), butyrate, propionate, and acetate, produced by bacterial fermentation of dietary fiber, can modulate the transcription of certain genes by inhibiting histone deacetylase in colonocytes and several other cell types in vitro. We previously reported that butyrate decreases tight junction permeability by activating lipoxygenase (LOX) in intestinal monolayer cells. In the present study, we evaluated the effects of SCFAs on tight junction permeability in an endothelial cell culture and their possible mechanisms of action via histone deacetylase inhibitor activity. We also investigated the factors modulating tight junction permeability.
Methods: The effects of butyrate, propionate, and acetate on tight junction permeability in human umbilical vein endothelial cells were examined using Transwell chamber cultures. The contributions of inducible nitric oxide synthase (NOS), endothelial NOS, estrogen receptor, cyclo-oxygenase, and LOX to SCFAs' effects were also evaluated. The effects of SCFAs were compared with those of trichostatin A, a typical histone deacetylase inhibitor.
Results: Low concentrations of butyrate and propionate decreased paracellular permeability without inducing cell damage. However, acetate decreased paracellular permeability in a concentration-dependent manner. An estrogen receptor antagonist attenuated the effects of SCFAs on tight junction permeability. The influences of inducible NOS, cyclo-oxygenase, and LOX inhibitors and the expressions of cyclo-oxygenase and LOX mRNAs were different for each SCFA. Trichostatin A slightly decreased paracellular permeability when used at lower concentrations, but higher concentrations of trichostatin A increased permeability.
Conclusion: The SCFAs play an important role in the assembly of tight junctions in normal vascular endothelial cells.
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http://dx.doi.org/10.1016/j.nut.2008.06.012 | DOI Listing |
Ann Allergy Asthma Immunol
January 2025
Department of Otorhinolaryngology Head and Neck Surgery, the Affiliated Hospital of Qingdao University, Qingdao, China. Electronic address:
Background: Recent studies show that M1 macrophages accumulate predominantly in non-eosinophilic chronic rhinosinusitis with nasal polyps (neCRSwNP). However, the precise mechanisms regulating M1 macrophages and their impact on the epithelial barrier remain unclear.
Objective: We aim to investigate the expression and regulatory role of SLAMF8, a molecule exclusively expressed in myeloid cells, in M1 macrophage polarization and its potential contribution to neCRSwNP development.
Inflammation
January 2025
Department of Pharmacy, Chinese PLA General Hospital, Beijing, China.
Cholestasis is a multifactorial hepatobiliary disorder, characterized by obstruction of bile flow and accumulation of bile, which in turn causes damage to liver cells and other tissues. In severe cases, it can result in the development of life-threatening conditions, including cirrhosis and liver cancer. Paeoniflorin (PF) has been demonstrated to possess favourable therapeutic potential for the treatment of cholestasis.
View Article and Find Full Text PDFThe gastrointestinal epithelium serves as a critical barrier separating intestinal lumen contents from the underlying tissue environment. Structure and function of the apical junctional complex (AJC), comprising tight and adherens junctions, are essential for establishing and maintaining a polarized and functional epithelial barrier. In this study, we investigated mechanisms by which an apical polarity protein Crumbs homolog 3 (CRB3) regulates AJC assembly and barrier function in primary murine intestinal epithelial cells.
View Article and Find Full Text PDFMol Immunol
January 2025
Department of Gastroenterology and Hepatology, Nantong Third People's Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu Province 226006, China. Electronic address:
Background: The intestinal mucosa of ulcerative colitis patients expresses high levels of interleukin 34, and mice lacking IL-34 have more severe DSS-induced experimental colitis. There are no studies on the effects of directly upregulating intestinal IL-34 on experimental colitis in mice.
Methods: The bacteria EcN/CSF-1 and EcN/IL-34, which express CSF-1 and IL-34, respectively, were genetically engineered from Escherichia coli Nissle 1917 (EcN).
Chemosphere
January 2025
Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life Earth and Environment, University of Namur, 61 Rue de Bruxelles, B-5000, Namur, Belgium.
ZnO and TiO nanoparticles (NPs) are widely employed for their antibacterial properties, but their potential environmental impact is raising concerns. This study aimed to assess their single and combined effects at environmentally relevant concentrations (210 μg L) on rainbow trout (Oncorhynchus mykiss) gills microbiota and immune functions. 16S rRNA gene sequencing performed after 5 and 28 days of exposure suggests that TiO NPs had a more immediate impact on bacterial diversity, while prolonged exposure to the mixture altered community composition.
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