Biology subjects

Noa Novershtern

Publications and source records attributed to Noa Novershtern.

3 recordsLinked to original sources

bioRxiv2015

Dynamic stem cell states: naive to primed pluripotency in rodents and humans

PrefaceThe molecular mechanisms and signalling pathways that regulate the in vitro preservation of distinct pluripotent stem cell configurations, and their induction in somatic cells via direct reprogramming approaches, continue to constitute a highly exciting area of research. In this review, we provide an integrative synthesis on recent discoveries related to isolating unique naive and primed pluripotent stem cell states with altered functional and molecular characteristics, and from different species. We overview pathways underlying pluripotent state transitions and interconversion in vitro and in vivo. We conclude by highlighting unresolved key questions, future directions and potential novel applications of such dynamic pluripotent cell states.

Developmental Biology↗

bioRxiv2015

Mbd3/NuRD is a Key Inhibitory Module During the Induction and Maintenance of Naïve Pluripotency

Our group has published a study on induced pluripotent stem cell (iPSC) reprogramming (Rais et al. Nature 20131) that reached the following conclusions: a) Mbd3/NuRD is a repressor of inducing naive pluripotency from mouse Epiblast stem cells (EpiSCs), primordial germ cells (PGCs), murine somatic cells and human secondary fibroblasts; b) Up to 100% iPSC formation efficiency can be achieved via optimized Mbd3/NuRD depletion, in concert with optimized OKSM delivery and naive pluripotency conditions (2i supplement applied only after 48 hours, human LIF, hypoxia and Vitamin C containing Knockout serum replacement)1. This represented the first proof for deterministic/near-deterministic iPSC reprogramming, and highlighted a previously unappreciated role for Mbd3/NuRD in hampering the re-establishment of pluripotency. Recent reports have seemingly provided contradictory results and attempted to dispute our iPSC efficiency quantifications and/or the role of Mbd3/NuRD in blocking reprogramming2,3. Here we provide a detailed response to these reports based on extended discussions and providing new data. The synthesis presented herein disagrees with claims made by Silva, Hendrich, Bertone and colleagues2,3, and reconfirms that Mbd3/NuRD is a major pathway that inhibits the maintenance and induction of pluripotency1. Further, we foresee that its controlled manipulation is likely to become an integral pathway for inducing and maintaining naive pluripotency in a variety of species.

Developmental Biology↗

bioRxiv2014

Frequent and Transient Acquisition of Pluripotency During Somatic Cell Trans-differentiation with iPSC Reprogramming Factors

Recent reports have proposed a new paradigm for obtaining mature somatic cell types from fibroblasts without going through a pluripotent state, by briefly expressing canonical iPSC reprogramming factors Oct4, Sox2, Klf4, c-Myc (abbreviated as OSKM) in cells expanded in lineage differentiation promoting conditions. Here we apply genetic lineage tracing for endogenous Nanog locus and X chromosome reactivation during OSKM induced trans-differentiation, as these molecular events mark final stages for acquisition of induced pluripotency. Remarkably, the majority of reprogrammed cardiomyocytes or neural stem cells derived from mouse fibroblasts via OSKM mediated trans-differentiation ([~]>90%), are attained after transient acquisition of pluripotency, and followed by rapid differentiation. Our findings underscore a molecular and functional coupling between inducing pluripotency and obtaining \"trans-differentiated\" somatic cells via OSKM induction, and have implications on defining molecular trajectories assumed during different cell reprogramming methods.

Developmental Biology↗