Schematic of paper summary. miR-294 and miR-181 each sensitize fibroblasts to epigenetic reprogramming through simultaneous inhibition of ot least fourteen and eleven targets, respectively. Targets with known functional modules are depicted here.

MicroRNA-based discovery of barriers to dedifferentiation of fibroblasts to pluripotent stem cells

___

This paper reports on four intertwined lines of experiments and conclusions that, although interdependent, are individually interesting.

  1. The miR-181 family can facilitate reprogramming into iPSCs and their endogenous expression is an important downstream tranient step during Oct4, Sox2 & Klf4 - driven reprogramming. This is a straight-forward but unexpected conclusion as miR-181 has also been shown to induce differentiation when overexpressed in ESCs.
  2. The miR-181 family, as well as the previously identified miR-294 / miR-302 miRNAs, enhance reprogramming during the early stages of the process, through destabilization of the fibroblastic program. They play a role in the initiation of the process, but not thereafter.
  3. The verified targets of both microRNA families constitute a gene set enriched for cooperative genetic interactions. This paper contains one of the first published functional genetic interaction maps in a mammalian system.
  4. These miRNAs have their effect on reprogramming through simultaneous regulation of at least three signaling pathways.

What does this all mean?

Together, these observations, combined with previously published studies, suggest an interesting model, whereby aberrantly expressed microRNAs destabilize a cell’s endogenous program through co-inhibition of many genes involved in several different cellular processes. This destabilization then sensitizes a cell to epigenetic reprogramming. In the case of miR-294 / miR-302, this destabilization is sufficient to permit changes in the growth media to fully reprogram fibroblasts to a pluripotent state. In the case or miR-181, a miRNA normally expressed in the brain and immune system, both the fibroblast program and the pluripotency program are destabilized, such that transient expression aids in OSK-induced de-differentiation, but prolonged expression has deleterious effects. Regardless of whether this proves to be the correct model to explain these data, the study does show that microRNAs are excellent tools for discovering novel functional genetic interactions.

Publications

___

CDK1 Inhibition Targets the p53-NOXA-MCL1 Axis, Selectively Kills Embryonic Stem Cells, and Prevents Teratoma Formation

Stem Cell Reports 2015

Noelle E Huskey, Tingxia Guo, Kimberley J Evason, Olga Momcilovic, David Pardo, Katelyn J Creasman, Robert L Judson, Robert Blelloch, Sco...

Two miRNA Clusters Reveal Alternative Paths in Late-Stage Reprogramming

Cell Stem Cell 2014

Ronald J Parchem, Julia Ye, Robert L Judson, Marie F Larussa,Raga Krishnakumar, Amy Blelloch, Michael C Oldham, Robert Blelloch

MicroRNA-based discovery of barriers to dedifferentiation of fibroblasts to pluripotent stem cells

Nature Structural & Molecular Biology 2013

Robert L Judson, Tobias S Greve, Ronald J Parchem, Robert Blelloch

microRNA Control of Mouse and Human Pluripotent Stem Cell Behavior

Annual Review of Cell and Developmental Biology 2013

Tobias S Greve, Robert L Judson, Robert Blelloch

Multiple targets of miR-302 and miR-372 promote reprogramming of human fibroblasts to induced pluripotent stem cells

Nature Biotechnology 2011

Deepa Subramanyam, Samy Lamouille, Robert L Judson, Jason Y Liu, Nathan Bucay, Rik Derynck, Robert Blelloch

miR-380-5p represses p53 to control cellular survival and is associated with poor outcome in MYCN-amplified neuroblastoma

Nature Medicine 2010

Alexander Swarbrick, Susan L Woods, Alexander Shaw, Asha Balakrishnan, Yuwei Phua, Akira Nguyen, Yvan Chanthery, Lionel Lim, Lesley J Ash...

Opposing microRNA families regulate self-renewal in mouse embryonic stem cells

Nature 2010

Collin Melton, Robert L Judson, Robert Blelloch

Embryonic stem cell-specific microRNAs promote induced pluripotency

Nature Biotechnology 2009

Robert L Judson, Joshua E Babiarz, Monica Venere, Robert Blelloch

The GP(Y/F) domain of TF1 integrase multimerizes when present in a fragment, and substitutions in this domain reduce enzymatic activity of the full-length protein

Journal of Biological Chemistry 2008

Hirotaka Ebina, Atreyi Ghatak Chatterjee, Robert L Judson, Henry L Levin

The self primer of the long terminal repeat retrotransposon Tf1 is not removed during reverse transcription.

Journal of Virology 2006

Angela Atwood-Moore, Kenneth Yan, Robert L Judson, Henry L Levin

Scroll top