Research

Research and Development Platforms

The Gift of Life Center of Cell and Gene Therapy is undertaking multiple research projects with the goal of developing methods and products that will expand the options for medical treatment and cure of life-threatening diseases. Since 1991, Gift of Life has operated a registry of blood stem cell and marrow donors, a database of tissue typed volunteers that now exceeds 400,000 individuals who are ready and willing to donate hematopoietic stem cells.

Our research projects build on fifteen years of previous work by Dr. Fran Gullo, Scientific Director. Our “Florida Cancer Center of Excellence” partners in the South Florida region, Florida Atlantic University, Moffitt Cancer Center, and Memorial Cancer Institute, are working with the Center for Cell and Gene Therapy to turn newly developed methods into products that will save the lives of patients.

In Vitro Expansion of Mobilized Peripheral Blood Stem Cells by Using Small Molecules

PROJECT BACKGROUND

The transplant of Hematopoietic Progenitor Cells (HPC) is a well-established therapy for blood cancers and other conditions. But the process involved in medical screening of volunteer donors and bringing them to a collection center makes it challenging to meet the needs of every patient within the timeframe required. Some patients do not receive a transplant quickly enough to change their outcome.

However, there is evidence that expansion of hematopoietic stem cells and progenitor cells (HSC/HPC) in ex vivo culture has the potential to be used as a method for increasing the restricted number of HSCs (F. Gullo, et al. Bioinformatics; 2015).

Expansion of HPCs through ex vivo cell culture methods can potentially enable multiple recipients to be helped by a single matching donor. Small molecules are powerful tools for expanding HSCs and dissecting the still-elusive regulatory networks that govern the self-renewal of human HSCs. They play a role in regulating stem cell fates with the advantages of easier manipulation and rapid phenotype-based high-throughput screening (Zhang et al., International Journal of Hematology; 2016).

The aim of this project is to screen a library of small molecules that play a key role in the HSC self-renewal and differentiation pathways in order to develop cocktails of cytokines and compounds that have the ability to promote the in vitro expansion of CD34+ cells while maintaining their stemness.

PROJECT IMPACT

Time to transplant is one of the most significant problems facing patients needing unrelated donors for stem cell transplants. Once a suitable donor is identified in the global registry, the average procurement time is 6-8 weeks. This is due to donor availability, collection center scheduling, the physical exam and medical clearance process, and mobilization timeline. Unfortunately, many patients never receive their transplant because their clinical condition deteriorates during this waiting period.

The expansion of HPCs through ex vivo cell culture methods could potentially enable multiple recipients to be helped by a single matching donor. This research study aims at helping more patients receive the transplants they need in the timeframe needed through the development of a BioBank of in vitro expanded HSCs. Since the products are already in long-term cryogenic storage, they can be available immediately when needed, and mitigate the impact of the lengthy procurement process.

A Comparative Study on MSC Subset Population CD73+CD39+

PROJECT BACKGROUND

Current knowledge of mesenchymal stem cells (MSCs) is limited due to difficulty obtaining cells and expansion without differentiation. Due to these gaps in knowledge, the properties and capabilities of MSC populations are not well known. It was reported that the coexistence of a single cell-derived clonal cell population (CD73+CD39+) with distinct differentiation potency existed within cultured MSCs from human synovial membrane. The combination of CD73 and CD39 allows the prospective purification from culture-expanded heterogeneous synovial MSC populations of a distinct MSC subset with greater chondro-osteogenic potency (F. Gullo; Rheumatology, 2013). Based on this study, we will compare this subset population from multiple MSC locales to understand whether the properties are specific to this population, and if they are shared within different areas of the body. Cells, enzymatically released from human bone marrow and adipose tissue, will be culture expanded. Phenotype analysis will be performed by flow cytometry using combinations of MSC markers, including the subset population stated. Sorting will be carried out using Miltenyi Biotec MACS Columns. Sorted cell populations will be assessed for clonogenicity, kinetics of growth, cell senescence and mesenchymal stem cell potency.

PROJECT IMPACT

Due to this study, we plan have to a better understanding of MSCs and the specificity of subsets in relation to the source. With more sources for obtaining MSCs, and more knowledge of the properties of MSC subset populations, further research can be done on the therapeutic capabilities of these cells. We anticipate that such an approach will enhance the consistency of cell-based therapeutic protocols for the repair of osteochondral defects.

Characterization, Expansion, and Differentiation of Mesenchymal Stem Cell Subset Population from Mobilized Peripheral Blood

PROJECT BACKGROUND

Mesenchymal stem cells (MSCs) are spindle-shaped cells commonly isolated from bone marrow, adipose tissue, and the synovium (connective tissue in joints) and are capable of multipotent differentiation in vitro. This means that they can self-renew and differentiate into a large range of cell types. The multipotent properties of MSCs make them an attractive choice for the development of clinical and therapeutic applications, due to their ability to replenish diseased or damaged cells (Wang et al., Journal of Hematology & Oncology; 2012).

Previously our research department reported that a subpopulation of MSCs positive for certain surface markers which allows for the prospective purification from cultured/uncultured expanded heterogenous synovial MSC populations. This subset accounts for a distinct adenosine producing population that expresses greater chondro-osteogenic potency (F. Gullo et al., Rheumatology; 2013). The Center for Cell and Gene therapy identified a marker on this subset that known to be associated with pericytes. This pericyte population was previously identified by its role of establishing a hematopoietic environment in a xeno-transplantation model (Sacchetti et al., Cell; 2007). Such data suggests a potential perivascular location along with hematopoietic support of the subset population.

The aim of this project is to isolate this specific subset of MSCs from mobilized peripheral blood and expand the subset in culture while maintaining their self-renewal and multipotent properties. Differentiation of the subset of MSCs into their multipotent linages will demonstrate whether this subset represents a population of MSCs that acts as pericytes which support hematopoiesis in the bone marrow niche. This research study also aims at mimicking the bone marrow niche by co-culturing our isolated MSC subset population with HSCs.

PROJECT IMPACT

Despite their largely untapped potential, MSCs are very rare, and expansion of MSCs is commonly required before clinical/therapeutic applications can be developed. However, prolonged culture of MSCs will cause replicative stress, senescence, loss of their multilineage potential, and loss of their immunosuppressive activity. Furthermore, heterogeneity across MSCs serves as a challenge as in desired therapeutic behaviors. The heterogeneity of MSCs combined with their limited expansion represents a current bottleneck in MSC research and application. The expansion of a specific subset population of MSCs with known characteristics could enable us to expand cells without inducing replicative stress or loss of their multilineage potential and would allow for more effective use of the cells in research and application. Furthermore, the coculture system could serve as a valuable asset for future treatment options to be readily available for cartilage repair, leukemia, and cardiovascular disease.