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Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

Kawaguchi D, Furutachi S, Kawai H, Hozumi K, Gotoh Y - Nat Commun (2013)

Bottom Line: Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis.Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny.Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.

ABSTRACT
Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

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Dll1 is asymmetrically segregated at NSC division.(a) Embryonic NSCs were prepared from neurosphere cultures of the mouse embryonic NCX at E11.5. The cells were subjected to immunofluorescence staining with antibodies to Dll1, phospho-vimentin (p-Vim) and Aurora B. Dll1+-dividing NSCs are shown. p-Vim and Aurora B are mitotic cell markers; Aurora B localizes to the central spindle at anaphase and to the midbody at telophase. Scale bar, 5 μm. (b) En-face views of the ventricular surface of the NCX, and coronal sections of the NCX and the GE of E14.5 mouse embryos stained as in a. Scale bar, 5 μm. (c) Adult SVZ NSCs were prepared from adult mouse SVZ. The cells were subjected to immunofluorescence staining with antibodies to Dll1, p-Vim, Aurora B and GFAP. Scale bar, 5 μm. (d, e) Divisions of activated NSCs (GFAP+ divisions) in the SVZ of intact adult brain (d) or in the SVZ of adult brain at 1 day after treatment with Ara-C for 6 days (e). Sections were stained for Dll1, p-Vim, Aurora B and GFAP as indicated. The total numbers of divisions examined (anaphase–telophase) were 326 and 45, the numbers of GFAP+ divisions among total divisions were 27/326 and 36/45, the numbers of Dll1+ divisions among GFAP+ divisions were 18/27 and 11/36, and the numbers of asymmetric Dll1 divisions among Dll1+GFAP+ divisions were 15/18 and 11/11 for d and e, respectively. These divisions were observed in a total of fifteen (d) and seven (e) brains. Scale bar, 5 μm.
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f5: Dll1 is asymmetrically segregated at NSC division.(a) Embryonic NSCs were prepared from neurosphere cultures of the mouse embryonic NCX at E11.5. The cells were subjected to immunofluorescence staining with antibodies to Dll1, phospho-vimentin (p-Vim) and Aurora B. Dll1+-dividing NSCs are shown. p-Vim and Aurora B are mitotic cell markers; Aurora B localizes to the central spindle at anaphase and to the midbody at telophase. Scale bar, 5 μm. (b) En-face views of the ventricular surface of the NCX, and coronal sections of the NCX and the GE of E14.5 mouse embryos stained as in a. Scale bar, 5 μm. (c) Adult SVZ NSCs were prepared from adult mouse SVZ. The cells were subjected to immunofluorescence staining with antibodies to Dll1, p-Vim, Aurora B and GFAP. Scale bar, 5 μm. (d, e) Divisions of activated NSCs (GFAP+ divisions) in the SVZ of intact adult brain (d) or in the SVZ of adult brain at 1 day after treatment with Ara-C for 6 days (e). Sections were stained for Dll1, p-Vim, Aurora B and GFAP as indicated. The total numbers of divisions examined (anaphase–telophase) were 326 and 45, the numbers of GFAP+ divisions among total divisions were 27/326 and 36/45, the numbers of Dll1+ divisions among GFAP+ divisions were 18/27 and 11/36, and the numbers of asymmetric Dll1 divisions among Dll1+GFAP+ divisions were 15/18 and 11/11 for d and e, respectively. These divisions were observed in a total of fifteen (d) and seven (e) brains. Scale bar, 5 μm.

Mentions: The size of the NSC pool might also be maintained by asymmetric cell division that produces one stem cell and one committed or differentiated cell. However, cell fate determinants that segregate asymmetrically during mammalian NSC mitosis have remained largely unknown. Dll1 is implicated as a cell fate determinant of NSCs, given that it is an essential ligand for Notch activation in both embryonic35 and adult (this study) NSCs within the forebrain and that it activates Notch in neighbouring cells (in trans) and inactivates Notch within the same cell (in cis) through direct binding and feedback loops313543. We noticed that Dll1 was often asymmetrically distributed at mitosis in cultured NSCs prepared from the mouse neocortex (NCX) on embryonic day (E) 11.5 (Fig. 5a). We also found that a subpopulation (34.7±4.5% in NCX, 29.0±3.1% in ganglionic eminence (GE)) of phosphorylated vimentin-positive mitotic cells at anaphase–telophase manifested punctate Dll1 immunoreactivity at E14.5 embryonic telencephalon (total counted cells=245 (NCX), 165 (GE), n=3 brains). Remarkably, most (87.4±5.9% in NCX, 76.3±6.9% in GE) Dll1+ mitotic cells manifested asymmetric distribution of Dll1 at anaphase–telophase (total counted cells=85 (NCX), 48 (GE), n=3 brains) (Fig. 5b).


Dll1 maintains quiescence of adult neural stem cells and segregates asymmetrically during mitosis.

Kawaguchi D, Furutachi S, Kawai H, Hozumi K, Gotoh Y - Nat Commun (2013)

Dll1 is asymmetrically segregated at NSC division.(a) Embryonic NSCs were prepared from neurosphere cultures of the mouse embryonic NCX at E11.5. The cells were subjected to immunofluorescence staining with antibodies to Dll1, phospho-vimentin (p-Vim) and Aurora B. Dll1+-dividing NSCs are shown. p-Vim and Aurora B are mitotic cell markers; Aurora B localizes to the central spindle at anaphase and to the midbody at telophase. Scale bar, 5 μm. (b) En-face views of the ventricular surface of the NCX, and coronal sections of the NCX and the GE of E14.5 mouse embryos stained as in a. Scale bar, 5 μm. (c) Adult SVZ NSCs were prepared from adult mouse SVZ. The cells were subjected to immunofluorescence staining with antibodies to Dll1, p-Vim, Aurora B and GFAP. Scale bar, 5 μm. (d, e) Divisions of activated NSCs (GFAP+ divisions) in the SVZ of intact adult brain (d) or in the SVZ of adult brain at 1 day after treatment with Ara-C for 6 days (e). Sections were stained for Dll1, p-Vim, Aurora B and GFAP as indicated. The total numbers of divisions examined (anaphase–telophase) were 326 and 45, the numbers of GFAP+ divisions among total divisions were 27/326 and 36/45, the numbers of Dll1+ divisions among GFAP+ divisions were 18/27 and 11/36, and the numbers of asymmetric Dll1 divisions among Dll1+GFAP+ divisions were 15/18 and 11/11 for d and e, respectively. These divisions were observed in a total of fifteen (d) and seven (e) brains. Scale bar, 5 μm.
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Related In: Results  -  Collection

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f5: Dll1 is asymmetrically segregated at NSC division.(a) Embryonic NSCs were prepared from neurosphere cultures of the mouse embryonic NCX at E11.5. The cells were subjected to immunofluorescence staining with antibodies to Dll1, phospho-vimentin (p-Vim) and Aurora B. Dll1+-dividing NSCs are shown. p-Vim and Aurora B are mitotic cell markers; Aurora B localizes to the central spindle at anaphase and to the midbody at telophase. Scale bar, 5 μm. (b) En-face views of the ventricular surface of the NCX, and coronal sections of the NCX and the GE of E14.5 mouse embryos stained as in a. Scale bar, 5 μm. (c) Adult SVZ NSCs were prepared from adult mouse SVZ. The cells were subjected to immunofluorescence staining with antibodies to Dll1, p-Vim, Aurora B and GFAP. Scale bar, 5 μm. (d, e) Divisions of activated NSCs (GFAP+ divisions) in the SVZ of intact adult brain (d) or in the SVZ of adult brain at 1 day after treatment with Ara-C for 6 days (e). Sections were stained for Dll1, p-Vim, Aurora B and GFAP as indicated. The total numbers of divisions examined (anaphase–telophase) were 326 and 45, the numbers of GFAP+ divisions among total divisions were 27/326 and 36/45, the numbers of Dll1+ divisions among GFAP+ divisions were 18/27 and 11/36, and the numbers of asymmetric Dll1 divisions among Dll1+GFAP+ divisions were 15/18 and 11/11 for d and e, respectively. These divisions were observed in a total of fifteen (d) and seven (e) brains. Scale bar, 5 μm.
Mentions: The size of the NSC pool might also be maintained by asymmetric cell division that produces one stem cell and one committed or differentiated cell. However, cell fate determinants that segregate asymmetrically during mammalian NSC mitosis have remained largely unknown. Dll1 is implicated as a cell fate determinant of NSCs, given that it is an essential ligand for Notch activation in both embryonic35 and adult (this study) NSCs within the forebrain and that it activates Notch in neighbouring cells (in trans) and inactivates Notch within the same cell (in cis) through direct binding and feedback loops313543. We noticed that Dll1 was often asymmetrically distributed at mitosis in cultured NSCs prepared from the mouse neocortex (NCX) on embryonic day (E) 11.5 (Fig. 5a). We also found that a subpopulation (34.7±4.5% in NCX, 29.0±3.1% in ganglionic eminence (GE)) of phosphorylated vimentin-positive mitotic cells at anaphase–telophase manifested punctate Dll1 immunoreactivity at E14.5 embryonic telencephalon (total counted cells=245 (NCX), 165 (GE), n=3 brains). Remarkably, most (87.4±5.9% in NCX, 76.3±6.9% in GE) Dll1+ mitotic cells manifested asymmetric distribution of Dll1 at anaphase–telophase (total counted cells=85 (NCX), 48 (GE), n=3 brains) (Fig. 5b).

Bottom Line: Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis.Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny.Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.

ABSTRACT
Stem cells often divide asymmetrically to produce one stem cell and one differentiating cell, thus maintaining the stem cell pool. Although neural stem cells (NSCs) in the adult mouse subventricular zone have been suggested to divide asymmetrically, intrinsic cell fate determinants for asymmetric NSC division are largely unknown. Stem cell niches are important for stem cell maintenance, but the niche for the maintenance of adult quiescent NSCs has remained obscure. Here we show that the Notch ligand Delta-like 1 (Dll1) is required to maintain quiescent NSCs in the adult mouse subventricular zone. Dll1 protein is induced in activated NSCs and segregates to one daughter cell during mitosis. Dll1-expressing cells reside in close proximity to quiescent NSCs, suggesting a feedback signal for NSC maintenance by their sister cells and progeny. Our data suggest a model in which NSCs produce their own niche cells for their maintenance through asymmetric Dll1 inheritance at mitosis.

Show MeSH