Mesenchymal stem/stromal cell-derived extracellular vesicles as therapeutic tool for Inflammatory Bowel Disease

Our recent experimental work clearly showed the limitations of the DSS model of colitis. In particular, this model is not lymphocyte-mediated and suffers from a considerable variability probably due to environmental factors. Our preliminary experience with a more chronic model (colitis induced by TNBS) was not encouraging, showing again a large variability in response. Moreover, our previous in vitro work showed that MSC-EVs involved both Treg and IL-10 production as possible mediators of the therapeutic effect. Therefore, alternative animal models such as the cell transfer model (lacking Treg) and the IL-10 knockout model could be unfeasible to test the effects of our product. For these reasons, we are developing an ex vivo assay using intestinal samples obtained at surgery from patients with Crohn’s disease (Prof. Imerio Angriman, General Surgery, Padua). This method would keep the sample viable under hyperoxic culture conditions for 24 hours, allowing testing the effects of drugs directly on the patient’s mucosa, by evaluating the expression and release of cytokines. Using this model, we will evaluate the effects of both “naïve” and An5-bound MSC-EVs.
Biodistribution studies are a requirement of Regulatory Authorities to allow first-in-man studies. Fluorescent-labeled MSC-EVs will be administered either via enema or IV both to helthy mice and to mice with DSS-induced colitis to follow the absorption and distribution of the nanoparticles in the different organs (in coll. with Antonio Rosato).

Mesenchymal stem/stromal cell-derived extracellular vesicles to prevent the development of Bronchopulmonary Dysplasia

Following our recently published positive results in vivo (Porzionato et al. 2018), we will administer both MSC-EVs and MSC-EV-An5 in the same animal model of BPD with a dose escalation approach. Moreover, since it has been reported that the beneficial effects of MSC-EVs are mediated by systemic effects on the immune system, we will evaluate the modifications of both innate and adaptive immune cell lineages in thymus, spleen and lung lymph nodes in treated groups compared to controls. Finally, we will also compare the effects of local vs. systemic administration.
Tests in vitro will include the effects of MSC-EVs on both innate and adaptive immunity in human cells. These tests could also help verify the activity of different EV batches for clinical application. Moreover, the same tests will help identify the mechanisms of action underlying the observed effects on different immune cell populations. To this end, we will evaluate the role of different proteins expressed on the surface of MSC-EVs with known immune modulatory properties, by knockout or hyperexpression approaches. Indeed, although the EV RNA cargo is a possible mediator of signals influencing the metabolism of target cells, it is now appreciated that probably most of the EV-mediated signals take place at the level of plasma membrane, while following internalization EVs are generally targeted to lysosomes where their content is degraded (Van Niel, D’Angelo and Raposo, 2018).
Biodistribution studies will help understand the effects on target organs. Fluorescent-labeled MSC-EVs will be administered either IT or IV to helthy (normoxic) newborn rats and to (hyperoxic) rats developing BPD to follow the absorption and distribution of nanoparticles in the different organs (in coll. with Prof. Antonio Rosato).

Role of extracellular vesicles in bone tumor pathogenesis: implications for therapy

In this project, we aim at understanding to what extent EVs are involved in the development of bone malignancies. More precisely, we will identify the pathways involved in EV tumorigenic functions and exploit their specific tropism to target cells and create new methods to fight cancer-induced bone diseases. Therefore, our project will be developed according to the following three main tasks:
• Investigate the involvement of EVs in the transfer of RANKL to target cells and in the activation of osteoclast bone resorption and angiogenesis during bone tumorigenesis: i) isolate, quantify and characterise RANKL-positive EVs released by osteoblasts; ii) treat osteoblasts with tumour cell conditioned media and isolate, quantify and characterise their RANKL-positive EV release; iii) investigate the effect of tumour-cell induced RANKL-positive EVs release by osteoblasts on osteoclast bone resorption and angiogenesis in vitro and in vivo.
• Characterise tumour-induced osteoblast EV RNA and protein profiles to identify molecular pathways and biological processes deregulated by bone malignancies.
• Employ osteoblast EVs loaded with chemotherapeutics to antagonise bone tumour growth.