Amino‐terminal region of secreted form of amyloid precursor protein stimulates proliferation of neural stem cells

Abstract

Beta-amyloid precursor protein (APP) has been reported to be expressed in the CNS from the early stages of development. However, the functional role of APP during early development remains unclear. In the present study, we found that the secreted form of APP (sAPP) significantly enhanced proliferation of neural stem cells. Cells were prepared from 13-day embryonic rat neocortex, which was dissected with a Pasteur pipette to make cell clusters. After 12 h of cultivation in the medium without serum, cells around the centre of the cluster were still nestin-positive proliferative cells, i.e. neural stem cells. To determine whether the proliferation of cells was regulated by sAPP, cultures were treated with recombinant sAPP695, the secreted form of human APP695 produced by yeast. Both DNA synthesis and expression of proliferating cell nuclear antigen markedly increased after 5 h of sAPP695 addition. The enhancement of DNA synthesis by sAPP695 stimulation was blocked by the 22C11 monoclonal antibody specific for the amino-terminal region of sAPP. Then, we examined the effect of the amino-terminal fragment of sAPP and the epitope peptide of 22C11 antibody, and found that both of them also promoted DNA synthesis, suggesting that the amino-terminal region of sAPP is responsible for the biological activity. Our findings indicate the possibility that sAPP enhances proliferation of neural stem cells in vivo and plays an important role during the early CNS development.

Soluble form of amyloid precursor protein regulates proliferation of progenitors in the adult subventricular zone

“…Cultured keratinocytes also exhibit sAPP-binding sites similar to the ones we observed in the SVZ or on cultured NS. In line with the results presented here, sAPP was described to stimulate proliferation of embryonic neural stem cells (Hayashi et al, 1994;Ohsawa et al, 1999). Accordingly, we could detect sAPP-binding sites not only on adult NS cells and SVZ but also on NS cells cultured from the embryonic brain (Fig.…”

“…A function for sAPP in regulating the proliferation of different cell types has been proposed in previous studies performed on cell lines (Hayashi et al, 1994;Hoffmann et al, 2000;Ohsawa et al, 1999;Pietrzik et al, 1998;Saitoh et al, 1989). Interestingly, sAPP has been described as an autocrine regulator of epidermal basal cell proliferation (Hoffmann et al, 2000), which, similar to SVZ progenitor proliferation, is under the control of TGFα, a member of the EGF family that acts though the EGF receptor.…”

“…Interestingly, infusion of sAPP into the brain increases synaptic density and improves memory retention (Meziane et al, 1998;Roch et al, 1994) and levels of sAPP are decreased in the CSF of individuals with AD (Lannfelt et al, 1995;Van Nostrand et al, 1992). Moreover, sAPP stimulates proliferation of neural stem cells isolated from the embryonic brain (Hayashi et al, 1994;Ohsawa et al, 1999).…”

Defective Neuromuscular Synapses in Mice Lacking Amyloid Precursor Protein (APP) and APP-Like Protein 2

“…sAPP has been suggested to exhibit neurotrophic, synaptogenic, and growth-promoting properties (Jin et al, 1994;Ohsawa et al, 1999;Rossjohn et al, 1999), and AICD has been reported to function in transcriptional regulation (Cao and Sudhof, 2001). A potential role of presenilin-dependent APP processing and signaling cannot be tested directly because of the early lethal phenotype of PS1/PS2 double null embryos (Donoviel et al, 1999;Herreman et al, 1999) and a large number of potential PS processing substrates reported (for review, see De Strooper, 2003).…”

Protection against ischemic brain injury by protein therapeutics

“…Neuroblastoma SH-SY5Y cells were cultured in DMEM (Invitrogen) with 15% FBS and 20 units͞ml penicillin-20 g͞ml streptomycin. Primary cultures of neocortical neurons were prepared from 18-day rat embryos as described (19,20) with slight modifications. In brief, neocortical tissues were cleaned of meninges, minced, and treated with 0.25% trypsin and 0.01% DNase I.…”