Hepatic molecular responses to Bifidobacterium pseudocatenulatum CECT 7765 in a mouse model of diet-induced obesity

Background and aims: Bifidobacterium pseudocatenulatum CECT 7765 moderates body weight gain and metabolic parameters in high-fat diet-(HFD)-fed mice but, the mechanisms of action are not yet understood. To further understand the effects of this bacterial strain, we have investigated the molecular changes in the liver of mice fed a HFD and supplemented with the bacteria. Methods and results: Gene expression and protein levels were measured in the liver of C57BL/6 male mice following sub-chronic consumption of a HFD and B. pseudocatenulatum CECT 7765. Our results show that the consumption of this bacterial strain modulated the expression of key genes involved in the regulation of energy metabolism and transport of lipids that were affected by the HFD. B. pseudocatenulatum CECT 7765 significantly counteracted the effects caused by the HFD on the fatty acid transporter CD36, the transcription regulator of lipid biosynthesis EGR1 and the regulators of glucose metabolism, IGFBP2 and PPP1R3B, both at the mRNA and protein levels. The bacterial strain slightly induced the transcript levels of PNPLA2, a lipase that hydrolyses triglycerides in lipid droplets. In the standard diet (SD)-fed mice, the administration of B. pseudocatenulatum CECT 7765 donwregulated the expression of INSIG1 and HMGCR critically involved in the regulation of cholesterol levels. Conclusion: B. pseudocatenulatum CECT 7765 modified the expression of key regulators of fatty acid and cholesterol metabolism and transport, lipid levels and glucose levels in the liver which supports the beneficial metabolic effects of this bacterial strain. (C) 2013 Elsevier B.V. All rights reserved.