ABSTRACT
We have investigated the effects of tCFA15, a non-peptidic compound, on the differentiation of neural stem cell-derived neurospheres, and have found that tCFA15 promotes their differentiation into neurons and reduces their differentiation into astrocytes, in a dose-dependent manner. This response is reminiscent of that resulting from the loss-of-function of Notch signaling after inactivation of the Delta-like 1 (Dll1) gene. Further analysis of the expression of genes from the Notch pathway by reverse transcriptase-PCR revealed that tCFA15 treatment results in a consistent decrease in the level of Notch1 mRNA. We have confirmed this result in other cell lines and propose that it reflects a general effect of the tCFA15 molecule. We discuss the implications of this finding with respect to regulation of Notch activity in neural stem cells, and the possible use of tCFA15 as a therapeutic tool for various pathologies that result from impairment of Notch signaling.
Subject(s)
Cell Differentiation/drug effects , Cyclohexanones/pharmacology , Fatty Alcohols/pharmacology , Neural Stem Cells/cytology , Neural Stem Cells/drug effects , Receptor, Notch1/metabolism , Animals , Astrocytes/cytology , Astrocytes/drug effects , Gene Expression Regulation/drug effects , Mice , Neural Stem Cells/metabolism , Neurons/cytology , Neurons/drug effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptor, Notch1/geneticsABSTRACT
In a search for inducers of neuronal differentiation to treat neurodegenerative diseases such as Alzheimer's disease, a series of indole fatty alcohols (IFAs) were prepared. 13c (n = 18) was able to promote the differentiation of neural stem cell derived neurospheres into neurons at a concentration of 10 nM. Analysis of the expression of the Notch pathway genes in neurospheres treated during the differentiation phase with 13c (n = 18) revealed a significant decrease in the transcription of the Notch 4 receptor.
Subject(s)
Alcohols/chemical synthesis , Fatty Alcohols/chemical synthesis , Free Radical Scavengers/chemical synthesis , Indoles/chemical synthesis , Neurons/drug effects , Stem Cells/drug effects , Alcohols/chemistry , Alcohols/pharmacology , Animals , Benzothiazoles , Cell Differentiation/drug effects , Fatty Alcohols/chemistry , Fatty Alcohols/pharmacology , Free Radical Scavengers/chemistry , Free Radical Scavengers/pharmacology , Free Radicals/chemistry , In Vitro Techniques , Indoles/chemistry , Indoles/pharmacology , Membrane Proteins/genetics , Membrane Proteins/physiology , Mice , Neurons/cytology , Oligonucleotides, Antisense/pharmacology , Proto-Oncogene Proteins/biosynthesis , Proto-Oncogene Proteins/genetics , Receptor, Notch1 , Receptor, Notch2 , Receptor, Notch4 , Receptors, Cell Surface/biosynthesis , Receptors, Cell Surface/genetics , Receptors, Notch , Reverse Transcriptase Polymerase Chain Reaction , Stem Cells/cytology , Structure-Activity Relationship , Sulfonic Acids/chemistry , Transcription Factors/biosynthesis , Transcription Factors/genetics , Transcription, GeneticABSTRACT
EGF-responsive C17 murine-derived neural stem cells (neurospheres) were grafted into the dentate gyrus of adult male rats after dentate granule cells lesions produced by colchicine injections. Behavioural performance was evaluated over two post-grafting periods, using tests sensitive to hippocampal dysfunctions. The first period began 1 month after grafting and testing conducted in the water maze and the radial maze distinguished working- and reference-memory performance. The second period began 9 months after grafting and learning performance was also evaluated in a Hebb-Williams maze, in addition to both other tests. The lesions induced lasting deficits in all tests. During the first period, the grafts had no effect in either test. Conversely, during the second period, grafted rats showed a weak improvement in the water maze and a significant increase of reference memory performance in the radial maze. In the Hebb-Williams maze, performance of grafted rats was close to normal. Strengthening the idea that dentate gyrus granule cells play an important role in the acquisition of new (perhaps more configural than only spatial) information, our results, moreover, suggest that neurosphere grafts may foster recovery after damage to point-to-point connection systems in the adult brain.
Subject(s)
Brain Tissue Transplantation/physiology , Dentate Gyrus/physiology , Maze Learning/physiology , Neurons/transplantation , Stem Cell Transplantation , Analysis of Variance , Animals , Dentate Gyrus/cytology , Dentate Gyrus/surgery , Fetal Tissue Transplantation , Follow-Up Studies , Graft Survival , Immunohistochemistry , Male , Memory/physiology , Mice , Neurons/cytology , Rats , Rats, Long-Evans , Telencephalon/cytology , Telencephalon/embryologyABSTRACT
We examined the role of Notch signaling on the generation of neurons and glia from neural stem cells by using neurospheres that are clonally derived from neural stem cells. Neurospheres prepared from Dll1(lacZ/lacZ) mutant embryos segregate more neurons at the expense of both oligodendrocytes and astrocytes. This mutant phenotype could be rescued when Dll1(lacZ/lacZ) spheres were grown and/or differentiated in the presence of conditioned medium from wild-type neurospheres. Temporal modulation of Notch by soluble forms of ligands indicates that Notch signaling acts in two steps. Initially, it inhibits the neuronal fate while promoting the glial cell fate. In a second step, Notch promotes the differentiation of astrocytes, while inhibiting the differentiation of both neurons and oligodendrocytes.
