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Front. Bioeng. Biotechnol. | doi: 10.3389/fbioe.2018.00173

Transdifferentiating astrocytes into neurons using ASCL1 functionalized with a novel intracellular protein delivery technology

Meghan Robinson1,  Ian Fraser1,  Emily McKee1, Kali Scheck1,  Lillian Chang2 and  Stephanie M. Willerth1*
  • 1University of Victoria, Canada
  • 2Bates College, United States

Cellular transdifferentiation changes mature cells from one phenotype into another by altering their gene expression patterns. Manipulating expression of transcription factors, proteins that bind to DNA promoter regions, regulates the levels of key developmental genes. Viral delivery of transcription factors can efficiently reprogram somatic cells, but this method possesses undesirable side effects, including as mutations leading to oncogenesis. Using protein transduction domains (PTDs) fused to transcription factors to deliver exogenous transcription factors serves as an alternative strategy that avoids the issues associated with DNA integration into the host genome. However, lysosomal degradation and inefficient nuclear localization pose significant barriers when performing PTD-mediated reprogramming. Here we investigate a novel PTD by placing a secretion signal sequence next to a cleavage inhibition sequence at the end of the target transcription factor - achaete scute homolog 1 (ASCL1), a powerful regulator of neurogenesis, resulting in superior stability and nuclear localization . A fusion protein consisting of the amino acid sequence of ASCL1 transcription factor with this novel PTD added can transdifferentiate cerebral cortex astrocytes into neurons. Additionally, we show that the synergistic action of certain small molecules improves the efficiency of the transdifferentiation process. This study serves as the first step towards developing a clinically relevant in vivo transdifferentiation strategy for converting astrocytes into neurons.

Keywords: reprogramming, transcription facotr, Neuroscience, small molecules, Drug Delivery & Targeting

Received: 12 Sep 2018; Accepted: 31 Oct 2018.

Edited by:

Gianni Ciofani, Politecnico di Torino, Italy

Reviewed by:

Madoka Suzuki, Osaka University, Japan
Stefania Moscato, University of Pisa, Italy  

Copyright: © 2018 Robinson, Fraser, McKee, Scheck, Chang and Willerth. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Stephanie M. Willerth, University of Victoria, Victoria, V8P 5C2, British Columbia, Canada, willerth@uvic.ca