Activated Notch1 maintains the phenotype of radial glial cells and promotes their adhesion to laminin by upregulating nidogen.
Radial glia are neural stem cells that exist only transiently during central nervous system (CNS) development, where they serve as scaffolds for neuronal migration. Their instability makes them difficult to study, and therefore we have isolated stabilized radial glial clones from E14.5 cortical progenitors (e.g., L2.3) after expression of v-myc. Activated Notch1 intracellular region (actNotch1) promotes radial glia in the embryonic mouse forebrain (Gaiano et al., (2000), and when it was introduced into E14.5 cortical progenitors or radial glial clone L2.3, the cells exhibited enhanced radial morphology and increased expression of the radial glial marker BLBP. A representative clone of L2.3 cells expressing actNotch1 called NL2.3-4 migrated more extensively than L2.3 cells in culture and in white matter of the adult rat spinal cord. Microarray and RT-PCR comparisons of mRNAs expressed in these closely related clones showed extensive similarities, but differed significantly for certain mRNAs including several cell adhesion molecules. Cell adhesion assays demonstrated significantly enhanced adhesion to laminin of NL2.3-4 by comparison to L2.3 cells. The laminin binding protein nidogen was the most highly induced adhesion molecule in NL2.3-4, and immunological analyses indicated that radial glia synthesize and secrete nidogen. Adhesion of NL2.3-4 cells to laminin was inhibited by anti-nidogen antibodies and required the nidogen binding region in laminin, indicating that nidogen promotes cell adhesion to laminin. The combined results indicate that persistent expression of activated Notch1 maintains the phenotype of radial glial cells, inhibits their differentiation, and promotes their adhesion and migration on a laminin/nidogen complex.
Li
Hedong
H
Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8082, USA. hedong@rci.rutgers.edu
Chang
Yu-Wen
YW
Mohan
Kriti
K
Su
Hui-Wen
HW
Ricupero
Christopher L
CL
Baridi
Ajoeb
A
Hart
Ronald P
RP
Grumet
Martin
M
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004622:Embryo, Mammalian; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins; D007797:Laminin / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009457:Neuroglia / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010641:Phenotype; D051381:Rats; D051881:Receptor, Notch1 / Q000378:metabolism*; D013116:Spinal Cord / Q000637:transplantation; D033581:Stem Cell Transplantation / Q000379:methods; D013234:Stem Cells / Q000502:physiology; D014162:Transfection; D015854:Up-Regulation / Q000502:physiology*
C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D007797:Laminin; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C497763:Notch1 protein, rat; D051881:Receptor, Notch1; C029967:nidogen; D049452:Green Fluorescent Proteins