Abstract

Mesenchymal Stromal/Stem Cells Promote Intestinal Epithelium Regeneration After Chemotherapy-induced Damage

Magdalena Lorenowicz, Head of the Advanced In Vitro Model Systems Department, Biomedical Primate Research Center

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for leukemia and a range of non-malignant disorders. The success of the therapy is hampered by occurrence of acute graft-versus-host disease (aGvHD); an inflammatory response damaging recipient organs, with gut, liver, and skin being the most susceptible. Intestinal GvHD injury is often a life-threatening complication in patients unresponsive to steroid treatment. Secondline available therapies are immunosuppressants or mesenchymal stromal/stem cell (MSC) infusions. Data from our institution and others demonstrate rescue of approximately 40-50% of patients suffering from aGvHD with mesenchymal stromal/stem cells (MSCs) and minor side effects. Although promising, better understanding of MSC mode of action and patient response to MSC-based therapy is essential to improve this lifesaving treatment. Here, we developed a 3D co-culture model of human small intestinal organoids and MSCs, which allows to study the regenerative effects of MSCs on intestinal epithelium in a more physiologically relevant setting than existing in vitro systems. Using this model we mimicked chemotherapymediated damage of the intestinal epithelium. The treatment with busulfan, the chemotherapeutic commonly used as conditioning regiment before the HSCT, affected pathways regulating epithelial to mesenchymal transition (EMT), proliferation, and apoptosis in small intestinal organoids, as shown by transcriptomic and proteomic analysis. The coculture of busulfan-treated intestinal organoids with MSCs reversed the effects of busulfan on the transcriptome and proteome of intestinal epithelium, which we also confirmed by functional evaluation of proliferation and apoptosis. Collectively, we demonstrate that our in vitro coculture system is a new valuable tool to facilitate the investigation of the molecular mechanisms behind the therapeutic effects of MSCs on damaged intestinal epithelium. This could benefit further optimization of the use of MSCs in HSCT patients.