Impact of Intestinal Epithelial Cells derived Extracellular Vesicles in regulating Intestinal Acute Graft-versus-Host Disease

• Applicant: Muhammad Haroon Shaikh, Ph.D.
• Subject Area: Hematology, Oncology ; Immunology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 549527997

Acute graft-versus-host disease (aGvHD) is a severe complication of allogeneic hematopoietic stem cell transplantation (allo-HCT), triggered by a dysregulated donor T cell response resulting in excessive tissue damage. aGvHD of the gastrointestinal tract (GIT) is a severe manifestation resulting in poor prognosis of patients after HCT. Currently, diagnosis and grading heavily rely on clinical symptoms, backed by invasive endoscopic and histopathological assessments, as serum biomarkers lack validation beyond clinical trials. In this project we propose to explore the pathophysiologic role of extracellular vesicles (EVs) in intestinal aGvHD and their potential as biomarkers for early detection and risk stratification. As our initial objective, 1) we will examine the small intestinal epithelial cell extracellular vesicles (IECEVs) in mice at steady state conditions and and in an MHC major mismatch GvHD mouse model to assess the phenotypic and functional alterations induced by myeloablatively irradiation and allo-HCT. 2) Our preliminary data suggest an important function of IECEVs in antigen presentation to allogeneic T cells. Therefore, we will explore this novel pathway of antigen presentation, we will employ experimental loss or gain of function strategies: (a) Systemic or local inhibition of EV synthesis using an inhibitory agent (GW4869) to establish loss of function). (b) Comparison of inflammatory IECEVs isolated from a mouse with intestinal aGvHD and infused into a mouse underdoing allo-HCT versus steady state IECEVs to demonstrate gain of function. These experiments aim to determine whether EVs from inflamed IECs exacerbate aGvHD severity or if blocking EV biosynthesis can alleviate aGvHD symptoms. In recent years EVs have emerged as promising liquid biopsy biomarkers for early diagnosis and risk-assessment of inflammation and cancer. 3) In our project we will assess serially collected serum-isolated EVs from patients who developed GvHD post allo-HCT, comparing them to EVs from healthy individuals. These EVs will undergo evaluation for differential expressed RNAs, proteins and lipids correlating with clinical GvHD progression and severity. The promising target candidates will be then validated by ELISA and/ or dPCR to affirms their applicability as a biomarker of intestinal aGVHD.

• DFG Programme: Research Grants
• International Connection: United Kingdom
• Cooperation Partner: Professor Naveed Akbar, Ph.D.