Human Cell Reprogramming via GATA3 and OCT4 Expression
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Solution Overview
Problem
Current methods for generating human induced trophoblast stem cells (iTSCs) face challenges such as incomplete lineage conversion and instability, with previous approaches failing to confer a stable true TSC phenotype, and there is a need for efficient methods to reprogram human cells into iTSCs or rejuvenate them.
Innovation Solution
The method involves expressing exogenous GATA3 and OCT4 transcription factors, optionally with KLF4, KLF5, and c-MYC, in human cells to generate stable and transgene-independent iTSCs that resemble endogenous TSCs in transcriptome, methylome, and function, allowing for prolonged culture and differentiation into trophoblastic lineages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If exogenous transcription factors are expressed to reprogram human cells into iTSCs, then cell identity conversion is achieved, but genomic stability and long-term maintenance of differentiation become problematic
Solution Approach 1:
The patent applies preliminary action by first expressing exogenous transcription factors (GATA3, OCT4, and optionally KLF4, KLF5, c-MYC) to initiate reprogramming, then systematically removing these factors after the initial conversion phase. This staged approach allows the cell to establish the iTSC phenotype before becoming independent of external factors, thereby achieving both conversion efficiency and long-term genomic stability.
Solution Approach 2:
The patent employs parameter changes by systematically varying the expression levels and combinations of transcription factors during different stages of reprogramming. By adjusting these molecular parameters over time (initial high expression followed by gradual reduction and removal), the method optimizes both the efficiency of cell identity conversion and the stability of the resulting iTSC line.
2Productivity
If multiple transcription factors are expressed to achieve complete lineage conversion, then conversion efficiency improves, but process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the reprogramming process into distinct phases: an initial induction phase where multiple transcription factors are co-expressed to drive lineage conversion, followed by a selection and expansion phase where factors are systematically removed. This temporal segmentation allows efficient conversion while simplifying the maintenance phase.
Solution Approach 2:
The patent uses partial action by expressing a core set of essential transcription factors (GATA3 and OCT4) while making other factors (KLF4, KLF5, c-MYC) optional. This approach achieves sufficient conversion efficiency for the target application without the full complexity of expressing all possible reprogramming factors, thereby optimizing the balance between productivity and process complexity.
3Reliability
If exogenous transcription factors are continuously expressed to maintain iTSC phenotype, then cell identity is stabilized, but transgene dependency and instability arise
Solution Approach 1:
The patent implements self-service by designing the reprogramming system so that the iTSCs, once established, maintain their differentiated phenotype through endogenous gene expression alone. The exogenous transcription factors serve only to initiate the reprogramming process and are then removed, allowing the cells to become self-sufficient and independent of continuous transgene expression, thereby achieving both identity stability and transgene independence.
Data Source
AI summary
A method of generating an induced trophoblast stem cell (iTSC) from a human cell is provided. Accordingly there is provided a method comprising expressing within a human cell GATA3 and OCT4 transcription factors, under conditions which allow generation of an iTSC from the cell. Also provided is a method of rejuvenating and/or de-differentiating a human cell. Also provided are nucleic acid constructs, protein preparation, isolated human cells, human iTSCs, rejuvenated cells and de-differentiated cells.