Greenway, StevenMack-Bowles, Brenan2024-09-192024-09-192024-09-17Mack-Bowles, B. (2024). Mechanisms of mycophenolic acid-induced gastrointestinal toxicity and potential therapeutic interventions in primary mouse colonic organoids (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.https://hdl.handle.net/1880/119819Mycophenolate Mofetil (MMF) is a commonly prescribed immunosuppressant that demonstrates important clinical relevance. However, MMF therapy is linked to frequent gastrointestinal (GI) side effects that limit its use. Little is known about the mechanisms underlying MMF-induced GI injury. Using a primary mouse colon organoid model, we have found that mycophenolic acid (MPA), the pharmacologically active metabolite of MMF, significantly alters intestinal barrier function and permeability through modulation of tight junctions. RNA sequencing revealed that MPA significantly disrupted pathways related to cell cycle regulation, DNA replication, cytoskeleton dynamics, and suppression of senescence. MPA was observed to significantly reduce cellular proliferation, which was ameliorated through guanosine supplementation. Addition of exogenous guanosine was also observed to significantly restore barrier function back to control levels. The guanosine studies presented in this thesis suggest MPA’s inhibition of nucleotide metabolism is not selective for lymphocytes but is broader than originally described. This work represents one of the first investigations of MPA using a colon organoid model, providing critical insights into the intracellular mechanisms of MPA-induced GI toxicity.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Mycophenolate mofetilMycophenolic acidImmunosuppressive therapyCell cultureOrganoidsGastrointestinal toxicityColonoid cultureIntestinal barrier functionTransepithelial resistanceFITC-dextran permeabilityTotal RNA-sequencingGuanosine supplementationIngenuity Pathway AnalysisColonoid monolayer culturePhysiologyBiology--CellBiology--MolecularPharmacologyImmunologymaster thesis