Harnessing the immunomodulatory capacity of dendritic cells differentiated from human induced pluripotent stem cells and the therapeutic potential of dendritic cell-derived exosomes for the treatment of lysosomal storage diseases

Thesis

Lysosomal storage diseases (LSDs) are a collection of disorders that feature the pathological accumulation of substrate frequently due to an enzymatic defect within the lysosomes. The most effective treatment regime for LSDs is enzyme replacement therapy. However, this treatment has faced two main challenges which have limited its treatment efficacy and clinical impact. One challenge constitutes the potential immunogenicity of the replaced enzyme, which can lead to the induction of an antibody response that prevents its effective targeting. Therefore, this thesis investigated the potential to derive patient-specific autologous dendritic cells (ipDCs) from fibroblasts which were obtained from a healthy donor and from a patient diagnosed with infantile-onset Pompe disease and were reprogrammed into induced pluripotent stem cells (iPSCs). This study demonstrated the feasibility of differentiating these iPSCs into ipDCs and investigated the potential to modulate their immunogenicity using a variety of agents. Using IL-10, this work was able to show the feasibility of generating patient-specific ipDCs with pro-tolerogenic characteristics which may be exploited for the induction of tolerance towards therapeutic enzymes. Secondly, the delivery of therapeutic enzymes to the central nervous system (CNS), which is frequently involved in disease pathogenesis, is limited by the selective-permeability of the blood brain barrier. As specifically-labelled exosomes have been shown capable of targeting to the CNS for the delivery of therapeutic molecules, this study has shown the possibility of harvesting exosomes from ipDC cultures. The potential of exploiting the endocytic capacity of dendritic cells for the loading of enzyme into exosomes was explored. Furthermore, this study has found that the administration of syngeneic and allogeneic exosomes from mouse bone-marrow derived DCs and ipDCs elicited an antibody-mediated immune response which may limit the clinical application of exosomes further highlighting the need for tolerance induction. Altogether, this study constitutes a first step towards potential improvements in the treatment of LSDs.

Authors: Leishman, A

• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English