Concise Review: Reprogramming, Behind the Scenes: Noncanonical Neural Stem Cell Signaling Pathways Reveal New, Unseen Regulators of Tissue Plasticity With Therapeutic Implications

Concise Review: Reprogramming, Behind the Scenes: Noncanonical Neural Stem Cell Signaling Pathways Reveal New, Unseen Regulators of Tissue Plasticity With Therapeutic Implications

Interest is great in the new molecular concepts that explain, at the level of signal transduction, the process of reprogramming. Usually, transcription factors with developmental importance are used, but these approaches give limited information on the signaling networks involved, which could reveal new therapeutic opportunities. Recent findings involving reprogramming by genetic means and sol- uble factors with well-studied downstream signaling mechanisms, including signal transducer and ac- tivator of transcription 3 (STAT3) and hairy and enhancer of split 3 (Hes3), shed new light into the molecular mechanisms that might be involved. We examine the appropriateness of common culture systems and their ability to reveal unusual (noncanonical) signal transduction pathways that actually operate in vivo. We then discuss such novel pathways and their importance in various plastic cell types, culminating in their emerging roles in reprogramming mechanisms. We also discuss a number of reprogramming paradigms (mouse induced pluripotent stem cells, direct conversion to neural stem cells, and in vivo conversion of acinar cells to b-like cells). Specifically for acinar-to-b-cell repro- gramming paradigms, we discuss the common view of the underlying mechanism (involving the Janus kinase-STAT pathway that leads to STAT3-tyrosine phosphorylation) and present alternative interpre- tations that implicate STAT3-serine phosphorylation alone or serine and tyrosine phosphorylation oc- curring in sequential order. The implications for drug design and therapy are important given that different phosphorylation sites on STAT3 intercept different signaling pathways. We introduce a new molecular perspective in the field of reprogramming with broad implications in basic, biotech- nological, and translational research.

Authors

STEVEN W. POSER, JOSH G. CHENOWETH, CARLO COLANTUONI, JIMMY MASJKUR, GEORGE CHROUSOS, STEFAN R. BORNSTEIN, RONALD MCKAY, ANDREAS ANDROUTSELLIS- THEOTOKIS

 

Journal 

Stem Cells Transl Med. 2015 Nov;4(11):1251-7. doi: 10.5966/sctm.2015-0105. Epub 2015 Sep 14.

 

PubMed link

http://www.ncbi.nlm.nih.gov/pubmed/?term=Noncanonical+Neural+Stem+Cell+Signaling+Pathways+Reveal+New%2C+Unseen+Regulators+of+Tissue+Plasticity+With+Therapeutic+Implications