McGowan Institute for Regenerative Medicine faculty members Johnny Huard, PhD (pictured top), and Burhan Gharaibeh, PhD (pictured bottom), along with investigators at the University of Pittsburgh / Children's Hospital of Pittsburgh of UPMC Stem Cell Research Center (SCRC), utilize a modified preplate technique, which separates cells based on their adhesion characteristic to collagen coated flasks, to isolate a population of muscle-derived stem cells (MDSCs). The ability of MDSCs to proliferate in vitro and in vivo for an extended period of time combined with their strong self-renewal ability and impressive multipotency suggests that MDSCs are a unique cell population that could significantly improve the efficiency of muscle cell-mediated therapies for tissue engineering applications to improve bone and cartilage healing as well as improve skeletal and cardiac muscle regeneration.
Recently, SCRC researchers used fluorescence-activated cell sorting (FACS) to isolate several populations of human muscle-derived cells from adult human skeletal muscle which included two populations of human muscle-derived blood vessel cells. These populations included pericytes and a novel population of cells that co-express myogenic and endothelial cell markers (myoendothelial cells). These myoendothelial (myo-endo) cells and pericytes have been shown to display a regenerative capacity in skeletal and cardiac muscles greater than that shown by human myoblasts and are therefore considered to be a human equivalent population to the murine MDSCs.
Continuing efforts planned include the comparison of the differentiation potential and other biological aspects of the murine MDSCs with induced-Pluripotent Stem (iPS) cells derived from MDSCs, and other conventional myogenic cell lines. Scientists believe such comparisons will provide vital information about the biological basis of the MDSCs’ superior abilities to survive, proliferate, and differentiate, and therefore enhance the regeneration of a variety of tissues including, but not limited to: skeletal and cardiac muscle, bone, articular cartilage, nerve, and blood. These comparison studies will provide insight as to the necessary genes and signaling pathways involved with the maintenance of pluripotent stem cell populations and the mechanisms that trigger and promote the differentiation of these cells into different lineages.
SCRC researchers are also interested in comparing the two human vascular-derived muscle cell populations (pericytes and myo-endo cells) to the same cells transduced as iPS cell. These populations will be compared for their regenerative potential, tolerance to oxidative stress, and their propensity to form tumor when implanted into certain tissues. By activating specific genes researchers have the ability to increase a cell’s pluripotency and proliferative and regenerative capacities, but also increase the potential of the cells to undergo neoplastic transformation. Using iPS technology gives scientists a powerful tool to dissect the delicate balances between stem cells and cancer stem cells. Furthermore, Drs. Huard and Gharaibeh believe that the use of the iPS technology will greatly facilitate cell and gene therapy for use in regenerative medicine, especially human disease-specific iPS cells (e.g., iPS cells from Duchenne Muscular Dystrophy patients).
Dr. Huard of the University of Pittsburgh is a professor in the Departments of Orthopaedic Surgery, Molecular Genetics, Biochemistry, Bioengineering, and Pathology, and is also the director of the Stem Cell Research Center. He has been named the Henry J. Mankin Endowed Chair in Orthopaedic Surgery Research. Dr. Huard is also deputy director for cellular therapy at the McGowan Institute for Regenerative Medicine and an associate director of the Pittsburgh Tissue Engineering Initiative (PTEI). Dr. Gharaibeh is a research assistant professor within the Stem Cell Research Center, part of the Department of Orthopedic Surgery at the University of Pittsburgh.
Illustration: McGowan Institute for Regenerative Medicine.
Gharaibeh, B., A. Lu, J. Tebbets, B. Zheng, J. Feduska, M. Crisan, B. Peault, J. Cummins, and J. Huard. 2008. Isolation of a slowly adhering cell fraction containing stem cells from murine skeletal muscle by the preplate technique. Nature Protocols. 3:1501-1509.
Stem Cell Research Center
Bio: Johnny Huard, PhD
Bio: Burhan Gharaibeh, PhD