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Updated: May 17, 2026

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Stimulation of Cytoplasmic DNA Sensing Pathways In Vitro and In Vivo
Published on: September 18, 2014
Activation of innate immunity is required for efficient nuclear reprogramming
Jieun Lee1, Nazish Sayed, Arwen Hunter
1Division of Cardiovascular Medicine, Stanford University, CA 94305, USA.
Cell
|October 30, 2012
Summary
Scientists found that activating the toll-like receptor 3 (TLR3) pathway enhances the efficiency of inducing pluripotency using viral or messenger RNA (mRNA) delivery methods for reprogramming factors.
Area of Science:
- Stem cell biology
- Molecular biology
- Immunology
Background:
- Induced pluripotent stem cells (iPSCs) are generated using reprogramming factors, but viral DNA integration can cause genomic issues.
- Cell-permeant proteins (CPPs) offer an alternative delivery method but are currently inefficient for reprogramming.
Purpose of the Study:
- To investigate the underlying reasons for the inefficiency of CPP-based reprogramming.
- To identify signaling pathways crucial for efficient nuclear reprogramming and iPSC generation.
Main Methods:
- Comparative gene expression analysis between viral and CPP delivery of reprogramming factors.
- Gain- and loss-of-function studies targeting the toll-like receptor 3 (TLR3) pathway.
- Assessment of epigenetic modifier expression and chromatin remodeling following TLR3 stimulation.
Main Results:
- A significant difference in gene expression patterns was observed between viral and CPP delivery methods.
- The toll-like receptor 3 (TLR3) pathway was identified as essential for efficient pluripotency induction via viral or mRNA delivery.
- TLR3 stimulation rapidly altered epigenetic modifiers, facilitating chromatin remodeling and nuclear reprogramming.
- Activation of inflammatory pathways, specifically via TLR3, is critical for efficient reprogramming.
Conclusions:
- The TLR3 pathway is a key mediator for efficient nuclear reprogramming and iPSC generation.
- Targeting TLR3 offers a promising strategy to overcome the limitations of current reprogramming techniques.
- Inflammatory pathway activation is integral to the process of inducing pluripotency.
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