Related Experiment Video
Updated: May 23, 2026
08:59
An Intestine/Liver Microphysiological System for Drug Pharmacokinetic and Toxicological Assessment
Published on: December 3, 2020
TLR2 controls intestinal carcinogen detoxication by CYP1A1
Khoa Nguyen Do1, Lisbeth Nielsen Fink, Thomas Elbenhardt Jensen
1Center for Biological Sequence Analysis, Technical University of Denmark (DTU), Lyngby, Denmark.
Plos One
|March 24, 2012
Summary
Toll-like receptor 2 (TLR2) is crucial for intestinal detoxification of carcinogens like polycyclic aromatic hydrocarbons (PAH). TLR2 deficiency silences intestinal CYP1A1, impairing carcinogen clearance and leading to colon polyp formation in mice.
Area of Science:
- Immunology
- Toxicology
- Gastroenterology
Background:
- Intestinal cytochrome P450 1A1 (CYP1A1) metabolizes carcinogens.
- CYP1 expression is regulated by the aryl hydrocarbon receptor (AHR) and ARNT.
- Toll-like receptor 2 (TLR2) modulates immune responses.
Purpose of the Study:
- Investigate the role of TLR2 in intestinal CYP1A1 regulation and carcinogen detoxification.
- Examine the impact of TLR2 deficiency on polycyclic aromatic hydrocarbon (PAH) metabolism and colon health.
Main Methods:
- Utilized TLR2-deficient (TLR2(-/-)) and wild-type mice.
- Administered benzo[a]pyrene (BaP), a carcinogenic PAH.
- Assessed intestinal and hepatic CYP1A1 expression.
- Measured BaP clearance and monitored colon polyp development.
Main Results:
- Intestinal CYP1A1 was silenced in TLR2(-/-) mice exposed to BaP.
- Hepatic CYP1A1 induction was insufficient to restore BaP clearance in TLR2(-/-) mice.
- TLR2(-/-) mice developed colon polyps after BaP feeding, unlike wild-type mice.
- AHR and ARNT levels remained unchanged between genotypes.
Conclusions:
- Bacterial TLR2 ligands are essential for intestinal CYP1A1-mediated detoxification of luminal carcinogens.
- A novel link exists between the host immune system, gut microbiota, and carcinogen metabolism.
- Intestinal microbiota plays a critical role in mammalian detoxification pathways and gut health.
Related Concept Videos
01:27Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Phase II biotransformation reactions are essential for detoxifying and eliminating xenobiotics, including many pharmaceutical compounds. These reactions typically involve conjugation, the covalent attachment of polar endogenous groups such as glucuronic acid, sulfate, methyl, or acetyl moieties to functional groups introduced during Phase I metabolism. The resulting conjugates are more water-soluble, enabling efficient renal or biliary excretion.The major classes of Phase II enzymes include...
01:19Phase II Reactions: Miscellaneous Conjugation Reactions
Phase II biotransformations are detoxification mechanisms that conjugate xenobiotics with endogenous substances, neutralizing their toxicity.
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
A key example involves the conjugation of cyanide ions, which impair cellular respiration and alter hemoglobin into non-oxygen-carrying cyanmethemoglobin. To neutralize this threat, a sulfur atom from thiosulphate is transferred to the cyanide ion, catalyzed by the enzyme rhodanese, resulting in an inactive compound called thiocyanate. The production of...
01:22Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation
Glutathione, a tripeptide made up of glutamate, cysteine, and glycine, is a critical player in the detoxification of drugs and xenobiotics via a process known as glutathione conjugation or mercapturic acid formation. This phase II biotransformation reaction involves the covalent binding of glutathione to a drug or its metabolite, enhancing the compound's water solubility and enabling its excretion.
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
01:28Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Cytochrome P450 (CYP450) enzymes are a superfamily of heme-containing monooxygenases that play a pivotal role in Phase I drug metabolism by catalyzing oxidation and reduction reactions.These enzymes transform lipophilic xenobiotics into more hydrophilic metabolites, facilitating subsequent Phase II conjugation and eventual excretion. The CYP450 family is classified into families (e.g., CYP1–CYP3) and subfamilies (e.g., CYP2A, CYP2C), based on amino acid sequence homology.CYP450 isoenzymes,...
01:14Drug Metabolism: Phase II Reactions
Phase II reactions are essential for the detoxification and elimination of drugs from the body. These reactions involve the conjugation of parent drugs or their phase I metabolites with endogenous molecules, resulting in more hydrophilic drug conjugates. The primary conjugation reactions in this phase are sulfation and glucuronidation. Both sulfation and glucuronidation typically produce biologically inactive metabolites. However, in some cases involving prodrugs, active metabolites may be...