Stem Cells and Regenerative Medicine

Research Activity

The research activity of the lab is focused on the development of in vivo and in vitro 3D constructs for regenerative medicine/tissue engineering approaches, using the expertise in skeletal muscle, stem cell biology and extracellular matrix engineering. A second line of research concerns the use of cellular vesicles from stromal mesenchymal cells as a therapeutic tool.
The research topics of the lab are the following.

Extracellular vesicles derived from mesenchymal stem/stromal cells as therapeutic tool

During the last decade, MSCs have been studied as a promising tool for regenerative medicine and anti-inflammatory tool. MSCs were originally described as stem cells, but it was later recognized that data supporting such a functional designation are still lacking, so the term stromal has been recommended by the International Society for Cellular Therapy. MSCs are plastic-adherent cells with a multipotent differentiation capacity in vitro. They can be isolated from a variety of tissues, including bone marrow, fat, cord blood and tissue, and placenta. MSCs are the most used cells in regenerative medicine because of their regulatory effect on the body’s immune response and their ability to protect tissues against a variety of injuries while enhancing regeneration and repair. MSCs were initially believed to differentiate and repopulate injured sites with tissue-specific cell phenotypes, but it soon became evident that the therapeutic effects observed were mediated by paracrine signals regulating immune response, counteracting apoptosis, limiting fibrogenesis, stimulating endogenous stem cells and thus resulting in tissue repair. In the last decade, accumulating evidence has shown that such signals are conveyed mainly by various membrane vesicles, including exosomes and microvesicles, collectively named extracellular vesicles (EVs). EVs are complex biological machines secreted by all cell types and ranging from 0.03 to 1 micron in size. They are distinguished mainly by their biogenesis, since they exhibit overlapping physical and chemical characteristics. EVs carry a variety of proteins, lipids and nucleic acids, with profound effects on the metabolism – and even on the phenotype – of the target cell. MSC-derived EVs have shown immune regulating effects in vitro and revealed a remarkable anti-inflammatory and pro-regenerative capacity in several animal models of disease. Our research group has developed a series of in vitro and ex vivo 3D models (like organoids of lung and intestine) to study Specific projects include:
• mesenchymal stem/stromal cell-derived extracellular vesicles to prevent and revert the development of Bronchopulmonary Dysplasia, the disease affects premature babies;
• mesenchymal stem/stromal cell-derived extracellular vesicles as therapeutic tool for acute respiratory distress syndrome and to prevent the development of interstitial lung fibrosis;
• mesenchymal stem/stromal cell-derived extracellular vesicles as therapeutic tool for Inflammatory Bowel Diseases;
• evaluation of 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.

Pathophysiology of extracellular matrix and tissue engineering

Extracellular vesicles in regenerative medicine and muscle dysfunction models. The need of new biomaterials to replenish the loss of muscle mass is currently a challenge. Indeed, after congenital malformations, trauma or tumor surgery the volume mass loss can be filled with synthetic materials already used in the clinical practice but the regain of function is still very difficult to reach. Nowadays the decellularization of tissues allows the obtainment of the highest biocompatible scaffold without the genetic material, such as the extracellular matrix (ECM). This biomaterial retains the biomechanical properties, proteins and biochemical factors that characterized the native tissue. ECM obtained removing the cellular components from the native tissue by means of decellularization, represents the optimal 3D support for cell culture since the in vivo microenvironment is recapitulated. We already demonstrated that engineered ECM actively integrate by inducing vascularization, cell recruitment and ECM production. On the other hand, adverse events such as foreign body response and fibrosis are prevented. With the aim to study the EV mechanism, the focus of the project is as follows.

• Muscle decellularized tissue will be engineered with human muscle precursor cells and macrophages. After damage, the EVs will be administered, and specific molecular pathways will be investigated. EVs from different cell sources (muscle precursor cells, amniotic fluid stem cells, cord blood mesenchymal stem cells, endothelial cells) will be considered and their biological activities evaluated.
• The presence of retained EVs in the decellularized matrix will be verified, and their biological activities in vitro will be evaluated.

Studies on the extracellular matrix of rhabdomyosarcoma. Rhabdomyosarcoma (RMS) is the most common and aggressive soft tissue sarcoma in childhood, quite often present in muscle tissue. Recently, the study of the tumor microenvironment and specifically of the extracellular matrix (ECM), highlighted the valuable role of the cross-talk between cells and their niche linking alteration of ECM composition to pathological outcomes. The interest in this new aspect starts widening the understanding of tumor progression and opens new avenues for developing innovative therapies.
We have already dissected the ECM protein composition and now we are focusing on the glycoproteins present in the intercellular part with specific focus on glypicans. A three-dimensional model hydrogel based with different cell population will be developed to study tumor behavior and to establish a platform for drug screening.