Lactobacillus rhamnosus strain GG restores alkaline phosphatase activity in differentiating Caco-2 cells dosed with the potent mycotoxin deoxynivalenol

Abstract

Deoxynivalenol (DON) contamination of cereal crops occurs frequently, and may cause acute exposure at high levels or chronic more moderate exposure. DON has proven toxicity including restriction of enterocyte differentiation, which may play a part in DON induced gastroenteritis. The probiotic bacteria Lactobacillus rhamnosus strain GG (GG) can bind DON, and therefore potentially restrict bioavailability of this toxin. Binding efficacy is not significantly altered by heat treatment, and therefore this in vitro study evaluated whether heat inactivated GG could restore the differentiation process in Caco-2 cells, using alkaline phosphatase (ALP) activity as a marker of differentiation. DON (200ng/mL) caused a significant (p<0.001) 36% reduction in ALP activity (1598±137U/mg protein) compared to untreated cells (2502±80U/mg). A dose dependant restoration of ALP activity was observed where DON treated cells were co-incubated with heat inactivated GG (1719±84; 2007±142; 2272±160U/mg for GG at 1×104 (p>0.9), 1×107 (p<0.001), and 1×1010CFU/mL (p<0.001), respectively). Co-incubation of the non-binding strain, LC-705 (1×1010CFU/mL), with DON did not significantly restore the ALP (1841±97U/mg, p<0.077) compared to DON only treated cells. When viable GG were co-incubated with DON a similar restoration of ALP activity was observed as seen for heat inactivated GG. These combined data suggest that the major effect of GG on restoring ALP activity, and therefore Caco-2 cell differentiation, was due to specific binding of DON, with possibly a more minor role of non-specific bacterial interference.