Neuronal Pentraxin 2 Binds PNNs and Enhances PNN Formation

Figure 4

NPTX2 enhances PNN formation. (a) Cortical neurons dissected from E18 rat brains were treated with NPTX2 in their standard neuronal medium from 14 DIV until 28 DIV. Neurons were fixed with 4% PFA and stained with WFA combined with parvalbumin (pv) antibody and his-tag antibody. (a) Representative images of PNN-positive neurons are shown (63x, ). (b) Lower magnification images (20x, ). (c) The amount of PNN-positive neurons/50 mm² was quantified and compared between cultures treated with NPTX2 or not. The number of PNN-positive neurons was significantly higher in cultures treated with NPTX2 (). This result indicates that at 28 DIV NPTX2 treatment has increased the number of PNN-positive neurons. For each PNN-positive neuron, the relative size (d) and intensity (e) of their PNN were measured by WFA PNN staining and analysed in ImageJ. It showed significant increase in PNN size in NPTX2-treated cultures () and significant increase in WFA intensity in NPTX2-treated cultures (). These results indicate that NPTX2 treatment caused neurons at 28 DIV to be further along in the development of a fully grown PNN (Student’s -test).

(a)

(b)

(c)

(d)

(e)