Gut microbiota provides a wide range of beneficial function for the host and has an immense effect on the host's health state. It has also been shown that gut microbiome is often involved in the biotransformation of xenobiotics; however, the molecular mechanisms of the interaction between the gut bacteria and the metabolism of drugs by the host are still unclear. To investigate the effect of microbial colonization on messenger RNA (mRNA) expression of liver cytochromes P450 (CYPs), the main drug-metabolizing enzymes, we used germ-free (GF) mice, lacking the intestinal flora and mice monocolonized by non-pathogenic bacteria Lactobacillus plantarum NIZO2877 or probiotic bacteria Escherichia coli Nissle 1917 compared to specific pathogen-free (SPF) mice. Our results show that the mRNA expression of Cyp1a2 and Cyp2e1 was significantly increased, while the expression of Cyp3a11 mRNA was decreased under GF conditions compared to the SPF mice. The both bacteria L. plantarum NIZO2877 and E. coli Nissle 1917 given to the GF mice decreased the level of Cyp1a2 mRNA and normalized it to the control level. On the other hand, the colonization by these bacteria had no effect on the expression of Cyp3a11 mRNA in the liver of the GF mice (which remained decreased). Surprisingly, monocolonization with chosen bacterial strains has shown a different effect on the expression of Cyp2e1 mRNA in GF mice. Increased level of Cyp2e1 expression observed in the GF mice was found also in mice colonized by L. plantarum NIZO2877; however, the colonization with probiotic E. coli Nissle 1917 caused a decrease in Cyp2e1 expression and partially restored the SPF mice conditions.

• MeSH
• Escherichia coli genetika   růst a vývoj   metabolismus   MeSH
• gnotobiologické modely MeSH
• játra enzymologie   MeSH
• Lactobacillus genetika   růst a vývoj   metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• myši inbrední BALB C MeSH
• myši genetika   mikrobiologie   MeSH
• střevní mikroflóra * MeSH
• systém (enzymů) cytochromů P-450 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši genetika   mikrobiologie   MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Metformin is widely used in the treatment of type-2 diabetes. The pleotropic effects of metformin on glucose and lipid metabolism have been proposed to be mediated by the activation of AMP-activated protein kinase (AMPK) and the subsequent up-regulation of small heterodimer partner (SHP). SHP suppresses the functions of several nuclear receptors involved in the regulation of hepatic metabolism, including pregnane X receptor (PXR), which is referred to as a "master regulator" of drug/xenobiotic metabolism. In this study, we hypothesize that metformin suppresses the expression of CYP3A4, a main detoxification enzyme and a target gene of PXR, due to SHP up-regulation. We employed various gene reporter assays in cell lines and qRT-PCR in human hepatocytes and in Pxr(-/-) mice. We show that metformin dramatically suppresses PXR-mediated expression of CYP3A4 in hepatocytes. Consistently, metformin significantly suppressed the up-regulation of Cyp3a11 mRNA in the liver and intestine of wild-type mice, but not in Pxr(-/-) mice. A mechanistic investigation of the phenomenon showed that metformin does not significantly up-regulate SHP in human hepatocytes. We further demonstrate that AMPK activation is not involved in this process. We show that metformin disrupts PXR's interaction with steroid receptor coactivator-1 (SRC1) in a two-hybrid assay independently of the PXR ligand binding pocket. Metformin also inhibited vitamin D receptor-, glucocorticoid receptor- and constitutive androstane receptor (CAR)-mediated induction of CYP3A4 mRNA in human hepatocytes. We show, therefore, a suppressive effect of metformin on PXR and other ligand-activated nuclear receptors in transactivation of the main detoxification enzyme CYP3A4 in human hepatocytes.

• MeSH
• aktivace transkripce MeSH
• cytochrom P-450 CYP3A genetika   metabolismus   MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• hypoglykemika farmakologie   MeSH
• koaktivátory jaderných receptorů metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• membránové proteiny genetika   metabolismus   MeSH
• messenger RNA metabolismus   MeSH
• metformin farmakologie   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• polohový reflex účinky léků   MeSH
• proteinkinasy aktivované AMP fyziologie   MeSH
• receptory cytoplazmatické a nukleární metabolismus   fyziologie   MeSH
• receptory glukokortikoidů fyziologie   MeSH
• receptory kalcitriolu fyziologie   MeSH
• reportérové geny MeSH
• signální transdukce MeSH
• steroidní receptory genetika   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Sexual differences and the composition/function of the gut microbiome are not considered the most important players in the drug metabolism field; however, from the recent data it is obvious that they may significantly affect the response of the patient to therapy. Here, we evaluated the effect of microbial colonization and sex differences on mRNA expression and the enzymatic activity of hepatic cytochromes P450 (CYPs) in germ-free (GF) mice, lacking the intestinal flora, and control specific-pathogen-free (SPF) mice. We observed a significant increase in the expression of Cyp3a11 in female SPF mice compared to the male group. However, the sex differences were erased in GF mice, and the expression of Cyp3a11 was about the same in both sexes. We have also found higher Cyp2c38 gene expression in female mice compared to male mice in both the SPF and GF groups. Moreover, these changes were confirmed at the level of enzymatic activity, where the female mice exhibit higher levels of functional CYP2C than males in both groups. Interestingly, we observed the same trend as with CYP3A enzymes: a diminished difference between the sexes in GF mice. The presented data indicate that the mouse gut microbiome plays an important role in sustaining sexual dimorphism in terms of hepatic gene expression and metabolism.

• Publikační typ
• časopisecké články MeSH