Zscan4 Reprogramming Factor Enhances iPS Cell Quality
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Solution Overview
Problem
The generation of induced pluripotent stem (iPS) cells using oncogenes like c-Myc raises concerns about tumorigenicity and genome stability, limiting their clinical applicability due to low efficiency and premature cellular senescence.
Innovation Solution
The forced expression of Zscan4, along with other reprogramming factors, initiates direct reprogramming of somatic cells, enhancing iPS cell production by reactivating early embryonic genes and utilizing Zscan4-dependent genes such as Patl2, Pramel6, Piwil2, and D5Ertd577e to promote efficient and high-quality iPS cell formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oncogenes like c-Myc are used together with reprogramming factors to generate iPS cells, then the efficiency of iPS cell formation increases, but tumorigenicity and genome stability are compromised
Solution Approach 1:
The patent removes the oncogene c-Myc from the reprogramming factor combination while retaining other essential factors (Oct4, Sox2, Klf4, Nanog, Lin28). This extraction eliminates the tumorigenicity risk and genome instability caused by c-Myc overexpression, while alternative methods (enhanced transfection efficiency, optimized culture conditions, use of small molecules) compensate to maintain adequate reprogramming efficiency without requiring the harmful oncogene.
2Productivity
If oncogenes like c-Myc are used to enhance iPS cell generation efficiency, then productivity increases, but premature cellular senescence occurs
Solution Approach 1:
The patent extracts c-Myc from the reprogramming factor set, eliminating its harmful effects on cellular lifespan and preventing premature senescence. The removal of this oncogene allows generated iPS cells to maintain normal replicative potential and avoid the accelerated aging phenotype associated with c-Myc expression, while other reprogramming factors sustain adequate differentiation capacity.
3Productivity
If c-Myc is used for efficient reprogramming, then reprogramming efficiency improves, but cell proliferation and genome stability become compromised
Solution Approach 1:
The patent removes c-Myc from the reprogramming cocktail, eliminating its dual harmful effects of disrupting genome stability and causing uncontrolled proliferation. Alternative approaches including enhanced delivery methods, optimized culture media, and supplementation with small molecules are employed to achieve sufficient reprogramming efficiency without the genomic instability and proliferative defects induced by oncogenic c-Myc.
Data Source
AI summary
Disclosed herein is the finding that Zscan4 is an early embryonic factor that facilitates cellular reprogramming. In particular, Zscan4 can replace the oncogenic reprogramming factor c-Myc to produce induced pluripotent stem cells when co-expressed with Klf4, Oct4 and Sox2. In addition, several Zscan4-dependent genes were identified that promote iPSC formation when co-expressed with known reprogramming factors. Thus, the present disclosure provides an ex vivo method of producing an iPS cell by reprogramming of a somatic cell. The method includes contacting the somatic cell with a Zscan4, or a Zscan4-dependent gene, and at least one reprogramming factor. Also provided are iPS cells produced by the disclosed method and non-human animals generated from such iPS cells.