Understanding the basic molecular elements that characterize somatic cells undergoing reprogramming to pluripotency is a prerequisite for advancing stem cell research towards clinical applications. One of the important questions in the field is whether the reprogramming process is driven by stochastic events that occur in no particular sequence or rather it is a more deterministic process that has a defined pattern of transcriptional changes that must occur sequentially to convert the differentiated cells to induced pluripotent stem cells (iPSCs). One of the major obstacles in deciphering these elements is the heterogeneity of the transduced cell population and the small fraction of cells that eventually will yield iPSCs. The fact that the majority of the studies in the field are based on cell-population analyses, which presumably do not represent the small fraction of cells that undergo reprogramming, strongly suggests that utilizing single cell techniques will be of paramount importance to understand the reprogramming process. Therefore, the main objective of my postdoctoral training will be to decipher the molecular mechanisms that define the reprogramming process using an innovative single cell technique that monitors the transcriptional profile of single cells. This technique will allow me to understand what the main events that occur during the reprogramming process are, in what chronological order they occur, and which genes are responsible for executing these events. I will then characterize the events and the key players that will be highlighted in my analysis to understand how they execute their function in the reprogramming process. Finally, I will generate knock-in secondary systems using the highlighted genes for future reprogramming studies. Addressing these questions will shed light on the molecular mechanisms that underlie the reprogramming process and will be a powerful tool to determine whether the reprogramming process is deterministic or stochastic.
The discovery that terminally differentiated cells can change their fate to become ES-like cells (i.e. reprogramming process) provides an invaluable resource for drug screening, medical research, and patient specific cell-based therapy. The proposed research will shed light on the mechanisms that define the true reprogramming process.
|Buganim, Yosef; Markoulaki, Styliani; van Wietmarschen, Niek et al. (2014) The developmental potential of iPSCs is greatly influenced by reprogramming factor selection. Cell Stem Cell 15:295-309|
|Faddah, Dina A; Wang, Haoyi; Cheng, Albert Wu et al. (2013) Single-cell analysis reveals that expression of nanog is biallelic and equally variable as that of other pluripotency factors in mouse ESCs. Cell Stem Cell 13:23-9|
|Buganim, Yosef; Faddah, Dina A; Jaenisch, Rudolf (2013) Mechanisms and models of somatic cell reprogramming. Nat Rev Genet 14:427-39|
|Buganim, Yosef; Faddah, Dina A; Cheng, Albert W et al. (2012) Single-cell expression analyses during cellular reprogramming reveal an early stochastic and a late hierarchic phase. Cell 150:1209-22|