LIF-Dependent Signaling: New Pieces in the Lego

LIF, a member of the IL6 family of cytokine, displays pleiotropic effects on various cell types and organs. Its critical role in stem cell models (e.g.: murine ES, human mesenchymal cells) and its essential non redundant function during the implantation process of embryos, in eutherian mammals, put this cytokine at the core of many studies aiming to understand its mechanisms of action, which could benefit to medical applications. In addition, its conservation upon evolution raised the challenging question concerning the function of LIF in species in which there is no implantation. We present the recent knowledge about the established and potential functions of LIF in different stem cell models, (embryonic, hematopoietic, mesenchymal, muscle, neural stem cells and iPSC). We will also discuss EVO-DEVO aspects of this multifaceted cytokine

Assessing the in vitro and in vivo toxicity of superparamagnetic iron oxide nanoparticles

Nanotechnology has become a key word of public interest, since people realized the social and economic power of nanotechnology development. Nanotechnology has already become part of our daily life, and it will have an as yet unknown technological impact because it concerns all aspects of human life from novel building materials to electronics, cosmetics, pharmaceutics, and medicine.1 In recent years, engineered nanoparticles started to become the most important components in nanotechnology. The InternationalOrganization for Standardization (ISO) has provided specific definitions in their recent document entitled “Nanotechnologies—Terminology and definitions for nanoobjects—Nanoparticle, nanofibre and nanoplate”. As the basis of this review, the following definitions for a nanoparticle (NP) and a nano-object will be used

A spatial and temporal map of FGF/Erk1/2 activity and response repertoires in the early chick embryo

AbstractDuring early vertebrate development Fibroblast Growth Factor (FGF) signalling is required for multiple activities including specification of mesodermal, neural and heart tissue, as well as gastrulation movements and regulation of differentiation and pattern onset in the extending body axis. A current challenge is to understand how FGF signalling generates such diverse outcomes. A key FGF downstream pathway is the Ras-MAPK/Erk1/2 cascade, which culminates in the phosphorylation of target proteins, such as the Ets family of transcription factors. To begin to assess specificity downstream of FGF in the chick embryo we have characterised the patterns of Fgfr1–4 expression and Erk1/2 activation, as well as expression of the Erk1/2 specific phosphatase, Mkp3 and of three Ets factor genes (Erm, Pea3 and Er81) from early blastula to the 10 somite stage. We identify new sites of Fgfr expression and show that nearly all regions of Erk1/2 activity are within Fgfr expression domains and require FGF signalling. Differences in intensity, duration, distribution and sub-cellular localisation of activated Erk1/2 are observed in distinct cell populations within the embryo and during wound healing. With few exceptions, a tight correspondence between Erk1/2 activation and Mkp3 expression is found, while specific combinations of Ets factors are associated with distinct regions of Erk1/2 activation. These findings provide a comprehensive spatial and temporal map of FGF/Erk1/2 activity during early chick development and identify region and tissue specific differences in expression of Fgfrs as well as Erk1/2 phosphorylation and transcriptional targets which help to define response specificity