Rat choroid plexuses contain myeloid progenitors capable of differentiation toward macrophage or dendritic cell phenotypes.
The interface between the blood and the cerebrospinal fluid (CSF) is formed by the choroid plexuses (CPs), which are specialized structures located within the brain ventricles. They are composed of a vascularized stroma surrounded by a tight epithelium that controls molecular and cellular traffic between the blood and the CSF. Cells expressing myeloid markers are present within the choroidal stroma. However, the exact identity, maturation state, and functions of these CP-associated myeloid cells are not fully clarified. We show here that this cell population contains immature myeloid progenitors displaying a high proliferative potential. Thus, in neonate rats and, to a lesser extent, in adult rats, cultured CP stroma cells form large colonies of macrophages, in response to M-CSF or GM-CSF, while, under the same conditions, peripheral blood monocytes do not. In addition, under GM-CSF treatment, free-floating colonies of CD11c(+) monocytic cells are generated which, when restimulated with GM-CSF and IL-4, differentiate into OX62(+)/MHC class II(+) dendritic cells. Interestingly, in CP stroma cultures, myeloid cells are found in close association with fibroblastic-like cells expressing the neural stem-cell marker nestin. Similarly, in the developing brain, macrophages and nestin(+) fibroblastic cells accumulate in vivo within the choroidal stroma. Taken together, these results suggest that the CP stroma represents a niche for myeloid progenitors and may serve as a reservoir for brain macrophages.
Nataf
Serge
S
INSERM U433, IFR 19, Faculté de Médecine Laennec and Hôpital Neurologique, Lyon, France. nataf@lyon.inserm.fr
Strazielle
Nathalie
N
Hatterer
Eric
E
Mouchiroud
Guy
G
Belin
Marie-Françoise
MF
Ghersi-Egea
Jean-François
JF
D000818:Animals; D000831:Animals, Newborn; D001854:Bone Marrow Cells / Q000166:cytology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002831:Choroid Plexus / Q000166:cytology*; D003713:Dendritic Cells / Q000166:cytology*; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D000949:Histocompatibility Antigens Class II / Q000502:physiology; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects; D051379:Mice; D051381:Rats; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D017154:Stromal Cells / Q000166:cytology
D000949:Histocompatibility Antigens Class II; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor