Intestinal mucosal barrier / Mucus layer & Short-chain fatty acids (SCFAs)

Diminished abundance of Short-Chain Fatty Acids (SCFAs) results in loss of Hypoxia and Barrier Integrity: Loss of cellular and luminal physiological hypoxia reduces HIF1 expression, resulting in the loss of tight junction and adhesion molecule expression and function. This allows bacterial translocation, triggering the innate immune response.
Overby & Ferguson 2021 Current Hypertension Reports 23: 8

Microbial SCFA production is essential for gut integrity by regulating the luminal pH, mucus production, providing fuel for epithelial cells , and effects on mucosal immune function
Blaak et al. 2020 Benefic. Microbes 11: 411-455

SCFAs also enforce epithelial barrier integrity by inducing mucus secretion from goblet cells and IL-22 production by ILC3 , the latter by a FFAR2 -dependent mechanism.
Stephen-Victor et al. 2020 Immunity 53(2): 277-289

SCFAs are an essential fuel for intestinal epithelial cells and strengthen the gut barrier function
Venegas et al. 2019 Front. Immunol. 10: 277

SCFAs enhance production of mucus by intestinal goblet cells
Rooks & Garrett 2016 Nature Rev. Immunology 16: 341

Short-chain fatty acids (SCAFs) are also important for strengthening the host epithelial barrier as they are able to enhance the Gut microbiota barrier effect
Fukuda et al. 2011 Nature 469: 543-547

see also:
Epithelial Barrier Integrity / Mucosal Barrier Integrity