Bone marrow contains a population of rare progenitor cells known as Mesenchymal Stem Cells (MSC) capable of replication as undifferentiated cells or differentiating into bone, cartilage, fat, muscle, tendon and marrow stroma. Due to the nature of mesenchymal stem cells (MSCs), they can play a vital role in several different types of research applications including cell differentiation and gene regulation, gene therapy and transplantation, and cell-based screening assays in drug discovery.

Cell Differentiation and Gene Regulation
The commitment of MSCs to a particular lineage is regulated by various signals from the cells' environment. Thus, there are many entry points into the process which can be exploited by researchers to help elucidate gene regulation and/or function. siRNA can be used to decrease the expression of a protein and allow one to better determine the function of the protein and pathways involved. Using stem cells allows one to study protein function and regulation at different stages in differentiation.

Gene Therapy and Transplantation
Mesenchymal stem cells have the potential to treat a wide range of diseases.  Compared to other types of stem cells, MSCs have the ability to take up and keep introduced genes, a phenomenon that could be exploited for the delivery of beneficial molecules to targeted locations.

Cell-based Screening Assays
Mesenchymal stem cells can be used in a variety of screening applications, from screening biomolecules against known targets or identifying potential targets through siRNA screening. Due to MSCs' ability to self-renew (replicate and proliferate without differentiation), one can easily obtain large cell numbers for running these types of assays. As some drug targets may only be expressed at certain time points during lineage differentiation, cell lines can yield inconsistent results as test models; however, primary stem cells will allow for identification of small molecules through the different stages of the differentiation process.