JAM-A is a novel surface marker for NG2-Glia in the adult mouse brain

Abstract

Background: Junctional adhesion molecule-A (JAM-A) is an adhesive protein expressed in various cell types. JAM-A localizes to the tight junctions between contacting endothelial and epithelial cells, where it contributes to cell-cell adhesion and to the control of paracellular permeability.

Results: So far, the expression pattern of JAM-A has not been described in detail for the different cell types of the adult brain. Here we show that a subset of proliferating cells in the adult mouse brain express JAM-A. We further clarify that these cells belong to the lineage of NG2-glia cells. Although these mitotic NG2-glia cells express JAM-A, the protein never shows a polarized subcellular distribution. Also non-mitotic NG2-glia cells express JAM-A in a non-polarized pattern on their surface.

Conclusions: Our data show that JAM-A is a novel surface marker for NG2-glia cells of the adult brain.

Figure 1

JAM-A is expressed in a subset of proliferating cells. Confocal images of immunostainings of vibratome sections from the subventricular zone of adult mouse brains labeled with the indicated markers (left boxes) are shown. (A) and (B) show proliferating P-H3 positive cells in two different magnifications. In (B) a maximum intensity projection of several optical layers is shown, the arrow points to a P-H3 positive and JAM-A negative cell, while the arrowhead indicates a P-H3 and JAM-A double positive cell. Scale bars: 10 μm

Figure 2

JAM-A is not expressed in stem and progenitor cells. Confocal images of immunostainings of vibratome sections from the subventricular zone ((A), (B) and (D)) and the rostral migratory stream (C) of adult mouse brains labeled with the indicated markers (upper boxes) are shown. To visualize GFAP expressing cells GFAP-GFP transgenic knock-in mice were used. Scale bars: 10 μm

Figure 3

Cells with a multiprocessed stellate morphology in different areas of the brain express JAM-A. Confocal images of immunostainings of vibratome sections from different regions of the adult brain (left boxes) labeled with the indicated markers (upper boxes) are shown. The right column shows a maximum intensity projection of several optical layers. All JAM-A positive cells from the various indicated brain areas show the same multiprocessed stellate morphology. Scale bars: 10 μm

Figure 4

JAM-A is not expressed in Neurons, Oligodendrocytes or Astroglia. Confocal images of immunostainings of vibratome sections from the rostral migratory stream and adjacent brain parenchyma (A), the subventricular zone (B) and the corpus callosum (C) labeled with the indicated markers (upper boxes) are shown. JAM-A staining is not overlapping with staining for Neurons (A, NeuN), Oligodendrocytes (B, GST-π) or Astrocytes (C, GFAP). To visualize GFAP expressing cells GFAP-GFP transgenic knock-in mice were used. Scale bars: 10 μm.

Figure 5

NG2-glia cells express JAM-A. Confocal images of immunostainings of vibratome sections from the corpus callosum labeled with the indicated markers (upper boxes) are shown. In (B) the cell body labeled with an arrow in (A) is shown at higher magnification. In (C) negative controls, where only one primary antibody but the two secondary antibodies anti-mouse-Alexa-568 nm (M-Alexa-568) and anti-rabbit-Alexa-488 nm (Rb-Alexa-488) have been used, are shown. Scale bars: 10 μm

Figure 6

PDGFRα positive NG2-glia cells express JAM-A. Confocal images of immunostainings of vibratome sections from the corpus callosum labeled with the indicated markers (upper boxes) are shown. The last panel shows a maximum intensity projection of several optical sections. Scale bars: 10 μm