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[Lineage-switching by pluripotent cells derived from adults]
1Institut d'Embryologie cellulaire et moléculaire du CNRS et du College de France, 49 bis, avenue de la Belle Gabrielle, 94736 Nogent-sur-Marne. dieterle@infobiogen.fr
Journal De La Societe De Biologie
|September 4, 2001
Summary
Recent research reveals unexpected stem cell plasticity, enabling fate switches under specific conditions. This discovery holds promise for cell therapy, but controlling transplanted stem cell proliferation remains a key challenge.
Area of Science:
- Developmental Biology
- Stem Cell Biology
- Cell Therapy
Background:
- Embryonic morphogenesis involves germ layer formation during gastrulation, with each layer typically giving rise to specific lineages.
- Historically, fate switches between germ layers were considered impossible, but recent findings demonstrate significant plasticity in stem cells.
- Stem cells, characterized by self-renewal and pluripotency, maintain tissue homeostasis and were previously thought to be lineage-restricted.
Purpose of the Study:
- To review recent discoveries regarding stem cell plasticity and its implications for cell therapy.
- To highlight novel methods for stem cell isolation and identification.
- To discuss the role of specific genes and experimental conditions in inducing stem cell fate switching.
Main Methods:
- Identification and isolation of stem cells using Hoechst 33342 dye efflux, defining a 'side population' (SP) with weak fluorescence.
- Analysis of the multidrug resistance (mdr) gene's role in dye efflux and toxin extrusion.
- Investigation of the Pax7 gene's role in muscle stem cell commitment and regeneration.
Main Results:
- Unexpected plasticity has been observed in stem cells, allowing differentiation into various lineages, including neural stem cells into diverse derivatives.
- The Pax7 gene acts as a commitment factor; its absence in Pax7-/- mice prevents muscle stem cell specification, redirecting SP cells towards hematopoietic lineages.
- Stem cell fate switching often requires drastic experimental conditions, such as sublethal irradiation combined with genetic deficiencies.
Conclusions:
- Recent findings underscore the plasticity of stem cells within their respective tissues, challenging previous notions of lineage restriction.
- Inducing phenotype switching in stem cells necessitates specific experimental manipulations and a deeper understanding of niche factors.
- Future progress in stem cell research, particularly for therapeutic applications, depends on identifying niche-specific factors and controlling transplanted stem cell proliferation.