EGF and bFGF pre-treatment enhances neural specification and the response to neuronal commitment of MIAMI cells.

Multipotent mesenchymal stromal cells raise great interest for regenerative medicine studies. Some MSC subpopulations have the potential to undergo neural differentiation, including marrow isolated adult multilineage inducible (MIAMI) cells, which differentiate into neuron-like cells in a multi-step neurotrophin 3-dependent manner. Epidermal and basic fibroblast growth factors are often used in neuronal differentiation protocols for MSCs, but with a limited understanding of their role. In this study, we thoroughly assessed for the first time the capacity of these factors to enhance the neuronal differentiation of MSCs. We have characterized MIAMI cell neuronal differentiation program in terms of stem cell molecule expression, cell cycle modifications, acquisition of a neuronal morphology and expression of neural and neuronal molecules in the absence and presence of an EGF-bFGF pre-treatment. EGF-bFGF pre-treatment down-regulated the expression of stemness markers Oct4A, Notch1 and Hes5, whereas neural/neuronal molecules Nestin, Pax6, Ngn2 and the neurotrophin receptor tyrosine kinase 1 and 3 were up-regulated. During differentiation, a sustained Erk phosphorylation in response to NT3 was observed, cells began to exit from the cell cycle and exhibit increased neurite-like extensions. In addition, neuronal β3-tubulin and neurofilament expression was increased; an effect mediated via the Erk pathway. A slight pre-oligodendrocyte engagement was noted, and no default neurotransmitter phenotype was observed. Overall, mesodermal markers were unaffected or decreased, while neurogenic/adipogenic PPARγ2 was incre ased. EGF and bFGF pre-treatment enhances neural specification and the response to neuronal commitment of MIAMI cells, further increasing their potential use in adult cell therapy of the nervous system

Adult cell therapy for brain neuronal damages and the role of tissue engineering

No long term effective treatments are currently available for brain neurological disorders such as stroke/cerebral ischemia, traumatic brain injury and neurodegenerative disorders. Cell therapy is a promising strategy, although alternatives to embryonic/foetal cells are required to overcome ethical, tissue availability and graft rejection concerns. Adult cells may be easily isolated from the patient body, therefore permitting autologous grafts to be performed. Here, we describe the use of adult neural stem cells, adrenal chromaffin cells and retinal pigment epithelium cells for brain therapy, with a special emphasis on mesenchymal stromal cells. However, major problems like cell survival, control of differentiation and engraftment remain and may be overcome using a tissue engineering strategy, which provides a 3D support to grafted cells improving their survival. New developments, such as the biomimetic approach which combines the use of scaffolds with extracellular matrix molecules, may improve the control of cell proliferation, survival, migration, differentiation and engraftment in vivo. Therefore, we later discuss scaffold properties required for brain cell therapy as well as new tissue engineering advances that may be implemented in combination with adult cells for brain therapy. Finally, we describe an approach developed in our laboratory to repair/protect lesioned tissues: the pharmacologically active microcarriers

Microencapsulation of proteins within CaCO3 microspheres using supercritical CO2 media

International audienc

Encapsulation de proteins thérapeutiques dans des microspheres de CaCO3 élaborées en milieu CO2 supercritique

National audienc

Synthesis of hollow vaterite CaCO(3) microspheres in supercritical carbon dioxide medium

We here describe a rapid method for synthesizing hollow core, porous crystalline calcium carbonate microspheres composed of vaterite using supercritical carbon dioxide in aqueous media, without surfactants. We show that the reaction in alkaline media rapidly conducts to the formation of microspheres with an average diameter of 5 mu m. SEM, TEM and AFM observations reveal that the microspheres have a hollow core of around 0.7 mu m width and are composed of nanograins with an average diameter of 40 nm. These nanograins are responsible for the high specific surface area of 16 m(2) g(-1) deduced from nitrogen absorption/desorption isotherms, which moreover confers an important porosity to the microspheres. We believe this work may pave the way for the elaboration of a biomaterial with a large potential for therapeutic as well as diagnostic applications

Elaboration of composite calcium carbonate microparticles in supercritical CO2

International audienc