Kime, Cody, 2011-2012

Cody Kime
Cody
Kime

Host research mentors: Tim Rand M.D., Ph.D.; Shinya Yamanaka, M.D., Ph.D.
University of California, San Francisco

In 2006, Shinya Yamanaka described a method for reprogramming fibroblasts to embryonic stem cells by defined factors, termed induced pluripotent stem cell (iPSC) reprogramming. Since then, iPSC have been achieved by other methods to include mRNA transfection and episomal expression vectors that rely on application of exogenous nucleic acids. mRNA based reprogramming is desirable for its non-integrating approach and versatility in daily mRNA dosing that may be finely tuned to overcome experimental challenges with potential gains in iPSC quality and efficiency. Such reprogramming requires persistent dosing of a vaccinia virus protein, B18R, which has been shown to quell human Type 1 and 2 interferon (IFN) signal transduction; yet as of late, mRNA reprogramming is limited to human cell lines due to specific cytokine affinity of B18R. In such reprogramming, IFN pathway activation occurs when cells respond the presence of exogenous nucleic acids, subsequently releasing cytokines and establishing signal transduction cascades that sensitize the activated and surrounding cells. IFN activation ultimately leads to downregulation of protein expression, senescence, and frequently to apoptosis, which presents significant obstacles for the 2-3 week timecourse of mRNA reprogramming in species where no significant IFN disruption is yet evident. We hope to expand the breadth of mRNA based reprogramming utility to other species by disrupting IFN pathway components with varied approaches to include application of other viral IFN adaptations, signal/receptor protein antagonism, and RNAi.