The extracellular matrix controls gap junction protein expression and function in postnatal hippocampal neural progenitor cells.
BACKGROUND
Gap junction protein and extracellular matrix signalling systems act in concert to influence developmental specification of neural stem and progenitor cells. It is not known how these two signalling systems interact. Here, we examined the role of ECM components in regulating connexin expression and function in postnatal hippocampal progenitor cells.


RESULTS
We found that Cx26, Cx29, Cx30, Cx37, Cx40, Cx43, Cx45, and Cx47 mRNA and protein but only Cx32 and Cx36 mRNA are detected in distinct neural progenitor cell populations cultured in the absence of exogenous ECM. Multipotential Type 1 cells express Cx26, Cx30, and Cx43 protein. Their Type 2a progeny but not Type 2b and 3 neuronally committed progenitor cells additionally express Cx37, Cx40, and Cx45. Cx29 and Cx47 protein is detected in early oligodendrocyte progenitors and mature oligodendrocytes respectively. Engagement with a laminin substrate markedly increases Cx26 protein expression, decreases Cx40, Cx43, Cx45, and Cx47 protein expression, and alters subcellular localization of Cx30. These changes are associated with decreased neurogenesis. Further, laminin elicits the appearance of Cx32 protein in early oligodendrocyte progenitors and Cx36 protein in immature neurons. These changes impact upon functional connexin-mediated hemichannel activity but not gap junctional intercellular communication.


CONCLUSIONS
Together, these findings demonstrate a new role for extracellular matrix-cell interaction, specifically laminin, in the regulation of intrinsic connexin expression and function in postnatal neural progenitor cells.
Imbeault
Sophie
S
Neural Regeneration Laboratory and Ottawa Institute of Systems Biology, Dept. of Biochemistry, Microbiology, and Immunology, University of Ottawa, ON, Canada. even_grable@hotmail.com
Gauvin
Lianne G
LG
Toeg
Hadi D
HD
Pettit
Alexandra
A
Sorbara
Catherine D
CD
Migahed
Lamiaa
L
DesRoches
Rebecca
R
Menzies
A Sheila
AS
Nishii
Kiyomasa
K
Paul
David L
DL
Simon
Alexander M
AM
Bennett
Steffany Al
SA
D000818:Animals; D015153:Blotting, Western; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000502:physiology*; D005434:Flow Cytometry; D006624:Hippocampus / Q000502:physiology*; D007150:Immunohistochemistry; D007797:Laminin / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009836:Oligodendroglia / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000502:physiology*
D017630:Connexins; D007797:Laminin; D012333:RNA, Messenger