Murine Intestinal Bacteria Modulate Antigen-Specific Cytokine Production by Intestinal Immune Cells Derived from Germ-Free TCR-Transgenic Mice

2008 ◽  
pp. 105-109
Author(s):  
Masato Tsuda ◽  
Akira Hosono ◽  
Tsutomu Yanagibashi ◽  
Satoshi Hachimura ◽  
Kazuhiro Hirayama ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Immune Cells ◽  
Cytokine Production ◽  
Intestinal Bacteria ◽  
Germ Free

scholarly journals Measurement of the Intestinal pH in Mice under Various Conditions Reveals Alkalization Induced by Antibiotics

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 180
Author(s):  
Kouki Shimizu ◽  
Issei Seiki ◽  
Yoshiyuki Goto ◽  
Takeshi Murata
Keyword(s):  
Antibiotic Treatment ◽  
High Protein Diet ◽  
Intestinal Bacteria ◽  
High Protein ◽  
Protein Diet ◽  
Germ Free ◽  
Treatment Regimens ◽  
Ph Values ◽  
Specific Pathogen ◽  
The Stability

The intestinal pH can greatly influence the stability and absorption of oral drugs. Therefore, knowledge of intestinal pH is necessary to understand the conditions for drug delivery. This has previously been measured in humans and rats. However, information on intestinal pH in mice is insufficient despite these animals being used often in preclinical testing. In this study, 72 female ICR mice housed in SPF (specific pathogen-free) conditions were separated into nine groups to determine the intestinal pH under conditions that might cause pH fluctuations, including high-protein diet, ageing, proton pump inhibitor (PPI) treatment, several antibiotic treatment regimens and germ-free mice. pH was measured in samples collected from the ileum, cecum and colon, and compared to control animals. An electrode, 3 mm in diameter, enabled accurate pH measurements with a small amount of gastrointestinal content. Consequently, the pH values in the cecum and colon were increased by high-protein diet, and the pH in the ileum was decreased by PPI. Drastic alkalization was induced by antibiotics, especially in the cecum and colon. The alkalized pH values in germ-free mice suggested that the reduction in the intestinal bacteria caused by antibiotics led to alkalization. Alkalization of the intestinal pH caused by antibiotic treatment was verified in mice. We need further investigations in clinical settings to check whether the same phenomena occur in patients.

In Vitro Observation of the Effect of Intestinal Bacteria on IgA Production by Immunocytes in the Large Intestine: Comparison Between Germ-Free and Conventional Mice

2008 ◽  
pp. 247-252
Author(s):  
Tsutomu Yanagibashi ◽  
Akira Hosono ◽  
Masato Tstuda ◽  
Satoshi Hachimura ◽  
Kazuhiro Hirayama ◽  
...  
Keyword(s):  
Large Intestine ◽  
Intestinal Bacteria ◽  
Germ Free ◽  
Iga Production

252 Hepatitis C virus impairs cytokine production by immune cells

Cytokine ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 299
Author(s):  
Marie-Eve Bilodeau ◽  
Emmanuel Moreau ◽  
Esther Tarrab ◽  
Alain Lamarre
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Immune Cells ◽  
Cytokine Production

scholarly journals Creating and Maintaining the Gastrointestinal Ecosystem: What We Know and Need To Know from Gnotobiology

1998 ◽  
Vol 62 (4) ◽  
pp. 1157-1170 ◽  
Author(s):  
Per G. Falk ◽  
Lora V. Hooper ◽  
Tore Midtvedt ◽  
Jeffrey I. Gordon
Keyword(s):  
Spatial Distribution ◽  
Immune System ◽  
Epithelial Cells ◽  
Immune Cells ◽  
Regional Differences ◽  
Germ Free ◽  
Experimental Strategy ◽  
Collaborative Interactions ◽  
Experimental Challenge ◽  
The Continuum

SUMMARY Studying the cross talk between nonpathogenic organisms and their mammalian hosts represents an experimental challenge because these interactions are typically subtle and the microbial societies that associate with mammalian hosts are very complex and dynamic. A large, functionally stable, climax community of microbes is maintained in the murine and human gastrointestinal tracts. This open ecosystem exhibits not only regional differences in the composition of its microbiota but also regional differences in the differentiation programs of its epithelial cells and in the spatial distribution of its component immune cells. A key experimental strategy for determining whether “nonpathogenic” microorganisms actively create their own regional habitats in this ecosystem is to define cellular function in germ-free animals and then evaluate the effects of adding single or several microbial species. This review focuses on how gnotobiotics—the study of germ-free animals—has been and needs to be used to examine how the gastrointestinal ecosystem is created and maintained. Areas discussed include the generation of simplified ecosystems by using genetically manipulatable microbes and hosts to determine whether components of the microbiota actively regulate epithelial differentiation to create niches for themselves and for other organisms; the ways in which gnotobiology can help reveal collaborative interactions among the microbiota, epithelium, and mucosal immune system; and the ways in which gnotobiology is and will be useful for identifying host and microbial factors that define the continuum between nonpathogenic and pathogenic. A series of tests of microbial contributions to several pathologic states, using germ-free and ex-germ-free mice, are proposed.

scholarly journals Pharmacological Activation of PXR and CAR Downregulates Distinct Bile Acid-Metabolizing Intestinal Bacteria and Alters Bile Acid Homeostasis

2018 ◽  
Vol 168 (1) ◽  
pp. 40-60 ◽  
Author(s):  
Joseph L Dempsey ◽  
Dongfang Wang ◽  
Gunseli Siginir ◽  
Qiang Fei ◽  
Daniel Raftery ◽  
...  
Keyword(s):  
Bile Acid ◽  
Gut Microbiota ◽  
Gut Microbiome ◽  
Corn Oil ◽  
Constitutive Androstane Receptor ◽  
Intestinal Bacteria ◽  
Pregnane X Receptor ◽  
Bile Salt Hydrolase ◽  
Dependent Manner ◽  
Germ Free

AbstractThe gut microbiome regulates important host metabolic pathways including xenobiotic metabolism and intermediary metabolism, such as the conversion of primary bile acids (BAs) into secondary BAs. The nuclear receptors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are well-known regulators for xenobiotic biotransformation in liver. However, little is known regarding the potential effects of PXR and CAR on the composition and function of the gut microbiome. To test our hypothesis that activation of PXR and CAR regulates gut microbiota and secondary BA synthesis, 9-week-old male conventional and germ-free mice were orally gavaged with corn oil, PXR agonist PCN (75 mg/kg), or CAR agonist TCPOBOP (3 mg/kg) once daily for 4 days. PCN and TCPOBOP decreased two taxa in the Bifidobacterium genus, which corresponded with decreased gene abundance of the BA-deconjugating enzyme bile salt hydrolase. In liver and small intestinal content of germ-free mice, there was a TCPOBOP-mediated increase in total, primary, and conjugated BAs corresponding with increased Cyp7a1 mRNA. Bifidobacterium, Dorea, Peptociccaceae, Anaeroplasma, and Ruminococcus positively correlated with T-UDCA in LIC, but negatively correlated with T-CDCA in serum. In conclusion, PXR and CAR activation downregulates BA-metabolizing bacteria in the intestine and modulates BA homeostasis in a gut microbiota-dependent manner.

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