Activation of human bitter taste receptor (TAS2R) subtypes and TAS2R14 genotypes by Bacillus amyloliquefaciens exopolysaccharides.

Bacillus amyloliquefaciens amy-1 is recognized as a probiotic for animals, and its exopolysaccharides (EPS) can lower blood sugar by activating specific human bitter-taste receptor type 2 (TAS2R) subtypes, particularly TAS2R14 and TAS2R38. Humans have 26 TAS2R subtypes, with some exhibiting different activities depending on genotype. However, differences in activity among TAS2R14 genotypes remain poorly studied. This research used THP-1 monocytes to identify TAS2Rs with high expression levels and analyzed how different TAS2R14 genotypes and other highly expressed subtypes respond to EPS. Accordingly, 8 genotypes of TAS2R14 (TIL, AIL, TVL, TIF, AVL, TVF, AIF, and AVF) that were created using site-directed mutagenesis, and TAS2R subtypes 5, 7, 16, 19, 20, 31, 41, and 42 were transfected into Gα-gustducin/HEK293T cells. Ca2+ fluorescence analysis with Fluo-4 showed that EPS activates all tested TAS2Rs, but with varying sensitivity and Ca2+ release levels. TAS2R14 (TIL) and TAS2R7 had the strongest activation. These results may inform further research on the activation of specific TAS2Rs by EPS and its potential as a therapeutic agent for human health.