Lactobacillus rhamnosus GG treatment potentiates intestinal hypoxia-inducible factor, promotes intestinal integrity and ameliorates alcohol-induced liver injury

Lactobacillus rhamnosus GG culture supernatant ameliorates acute alcohol-induced intestinal permeability and liver injury

Endotoxemia is a contributing cofactor to alcoholic liver disease (ALD), and alcohol-induced increased intestinal permeability is one of the mechanisms of endotoxin absorption. Probiotic bacteria have been shown to promote intestinal epithelial integrity and protect barrier function in inflammatory bowel disease (IBD) and in ALD. Although it is highly possible that some common molecules secreted by probiotics contribute to this action in IBD, the effect of probiotic culture supernatant has not yet been studied in ALD. We examined the effects of Lactobacillus rhamnosus GG culture supernatant (LGG-s) on the acute alcohol-induced intestinal integrity and liver injury in a mouse model. Mice on standard chow diet were supplemented with supernatant from LGG culture (10(9) colony-forming unit/mouse) for 5 days, and one dose of alcohol at 6 g/kg body wt was administered via gavage. Intestinal permeability was measured by FITC-FD-4 ex vivo. Alcohol-induced liver injury was examined by measuring the activity of alanine aminotransferase (ALT) in plasma, and liver steatosis was evaluated by triglyceride content and Oil Red O staining of the liver sections. LGG-s pretreatment restored alcohol-induced reduction in ileum mRNA levels of claudin-1, intestine trefoil factor (ITF), P-glycoprotein (P-gp), and cathelin-related antimicrobial peptide (CRAMP), which play important roles on intestinal barrier integrity. As a result, LGG-s pretreatment significantly inhibited the alcohol-induced intestinal permeability, endotoxemia and subsequently liver injury. Interestingly, LGG-s pretreatment increased ileum mRNA expression of hypoxia-inducible factor (HIF)-2α, an important transcription factor of ITF, P-gp, and CRAMP. These results suggest that LGG-s ameliorates the acute alcohol-induced liver injury by promoting HIF signaling, leading to the suppression of alcohol-induced increased intestinal permeability and endotoxemia. The use of bacteria-free LGG culture supernatant provides a novel strategy for prevention of acute alcohol-induced liver injury.

Carboxy terminus of heat shock protein (HSP) 70-interacting protein (CHIP) inhibits HSP70 in the heart

Heat shock protein (HSP) 70 plays a critical role in protecting the heart from various stressor-induced cell injuries; the mechanism remains to be further understood. The present study aims to elucidate the effect of a probiotics-derived protein, LGG-derived protein p75 (LGP), in alleviating the ischemia/reperfusion (I/R)-induced heart injury. We treated rats with the I/R with or without preadministration with LGP. The levels of HSP70 and carboxy terminus of HSP70-interacting protein (CHIP) in the heart tissue were assessed by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The effect of CHIP on suppression of HSP70 and the effect of LGP on suppression of CHIP were investigated with an I/R rat model and a cell culture model. The results showed that I/R-induced infarction in the heart could be alleviated by pretreatment with LGP. HSP70 was detected in naïve rat heart tissue extracts. I/R treatment significantly suppressed the level of HSP70 and increased the levels of CHIP in the heart. A complex of CHIP/HSP70 was detected in heart tissue extracts. The addition of recombinant CHIP to culture inhibited HSP70 in heart cells. LGP was bound CHIP in heart cells and prevented the CHIP from binding HSP70. In summary, I/R can suppress HSP70 and increase CHIP in heart cells. CHIP can suppress HSP70 that can be prevented by pretreatment with LGP. The results imply that CHIP may be a potential target in the prevention of I/R-induced heart cell injury.