Intrinsic Xenobiotic Resistance of the Intestinal Stem Cell Niche

Area of Science:

• Gastroenterology
• Cell Biology
• Pharmacology

Background:

• The intestinal epithelium rapidly regenerates to handle nutrient absorption and xenobiotic exposure.
• Subepithelial myofibroblasts are crucial for stem cell niche signaling, secreting Wnt proteins.
• Oral Wnt inhibitors typically disrupt intestinal homeostasis.

Purpose of the Study:

• To investigate the unexpected resistance of the intestinal stem cell niche to Wnt inhibitors.
• To identify mechanisms underlying xenobiotic resistance in intestinal myofibroblasts.

Main Methods:

• Administration of PORCN inhibitors and doxorubicin to mice.
• Analysis of drug transporter expression in intestinal myofibroblasts.
• Gene knockout studies (Mrp1/Abcc1).
• Tamoxifen-inducible lineage tracing in Rosa26^{CreERT2;mT/mG} mice.

Main Results:

• Intestinal myofibroblasts exhibit intrinsic resistance to PORCN inhibitors and doxorubicin.
• High expression of drug transporters, including Mrp1/Abcc1, contributes to this resistance.
• Knocking out Mrp1/Abcc1 increases myofibroblast drug sensitivity.
• Lineage tracing identified a drug-resistant stromal compartment in the gut and other organs.

Conclusions:

• Intestinal myofibroblasts possess inherent xenobiotic resistance, safeguarding the stem cell niche.
• Drug transporters play a key role in protecting these critical Wnt-secreting cells.
• This resistance mechanism is vital for maintaining intestinal homeostasis in a toxic environment.