With the ability to differentiate into almost any cell in the body, pluripotent cells represent a powerful tool for regenerative medicine and repair of deficient tissues such as bone. Several challenges to their clinical application remain, however, chief among which is their propensity to form tumors. Spontaneous teratoma formation has been frequently observed following implantation of induced pluripotent cells or embryonic stem cells. While approaches such as immunodepletion of SSEA-5+ cells by FACS, incorporation of suicide genes responsive to ganciclovir, and use of small molecular inhibitors have been described, none have proven completely successful. Recent studies have now shown the epigenetic landscape to play a key role in the specification of cell fate, and understanding how this may be regulated would be critial to facilitate safe and efficient use of pluripotent cells in therapeutic strategies to replace deficient tissues such as bone. Emerging data have described a novel class of noncoding RNAs ranging from 200 nucleotides to over 10 kilobases that are roughly as diverse in a given cell type as protein---coding mRNA. These long noncoding RNAs have been found to interact with small molecule regulators of histone methylation, targeting specific domain for transcriptional activity or gene silencing. How long noncoding RNAs are controlled and their precise role in regulating differentiation remains undefined, but with better understanding, the potential exists to redirect the developmental process in pluripotent cells. This will be the focus of our proposal. We will evaluate how induced pluripotent stem cells and embryonic stem cells respond to BMP-2 with definition of whole transcriptome response and changes to the chromatin landscape. Integrating data from both cell lines, we will then identify novel long noncoding transcripts responsive to BMP-2. We wil look to manipulate these novel long noncoding RNA transcripts and evaluate for changes to the pluripotent state and bone differentiation potential. Finally, we will also evaluae the in vivo response of pluripotent cells following manipulation of novel long noncoding RNAs. Specifically, the ability for both bone regeneration in a critical-sized calvaril defect model and the teratoma formation potential will be evaluated. We expect result of these innovative studies to identify a ground---breaking approach to understand and regulate cell fate determination, allowing for development of safe cell---based therapies employing pluripotent cells.
Pluripotent cells possess the ability to form almost any cell type making them ideal for strategies to repair complex defects in the head and neck and throughout the entire body. How these cells may be safely guided to mature, functional tissue, however, remains undefined. By studying novel mechanisms that regulate activity of large groups of genes, this will facilitate efficient use of pluripotent cells in regenerative medicine while simultaneously minimizing any adverse outcomes.