Modulation of human neural stem cell differentiation in Alzheimer (APP23) transgenic mice by phenserine.

Biomolecular Sciences Center, Burnett College of Biomedical Sciences, University of Central Florida, Orlando, FL 32816, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 08/2007; 104(30):12506-11. DOI: 10.1073/pnas.0705346104
Source: PubMed

ABSTRACT In a previous study, we found that human neural stem cells (HNSCs) exposed to high concentrations of secreted amyloid-precursor protein (sAPP) in vitro differentiated into mainly astrocytes, suggesting that pathological alterations in APP processing during neurodegenerative conditions such as Alzheimer's disease (AD) may prevent neuronal differentiation of HNSCs. Thus, successful neuroplacement therapy for AD may require regulating APP expression to favorable levels to enhance neuronal differentiation of HNSCs. Phenserine, a recently developed cholinesterase inhibitor (ChEI), has been reported to reduce APP levels in vitro and in vivo. In this study, we found reductions of APP and glial fibrillary acidic protein (GFAP) levels in the hippocampus of APP23 mice after 14 days treatment with (+)-phenserine (25 mg/kg) lacking ChEI activity. No significant change in APP gene expression was detected, suggesting that (+)-phenserine decreases APP levels and reactive astrocytes by posttranscription regulation. HNSCs transplanted into (+)-phenserine-treated APP23 mice followed by an additional 7 days of treatment with (+)-phenserine migrated and differentiated into neurons in the hippocampus and cortex after 6 weeks. Moreover, (+)-phenserine significantly increased neuronal differentiation of implanted HNSCs in hippocampal and cortical regions of APP23 mice and in the CA1 region of control mice. These results indicate that (+)-phenserine reduces APP protein in vivo and increases neuronal differentiation of HNSCs. Combination use of HNSC transplantation and treatment with drugs such as (+)-phenserine that modulate APP levels in the brain may be a useful tool for understanding mechanisms regulating stem cell migration and differentiation during neurodegenerative conditions in AD.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Neurotrophic factors can promote the proliferation and differentiation of neural stem cells (NSCs). Here we report that the possibility of using bFGF in combination with BDNF and NGF to promote proliferation and differentiation of NSCs in vitro. C57BL/6 mouse NSCs were cultured, passaged and stained by immunofluorescence for nestin and GFP. According to different neurotrophic factors added to NSCs, seven experiment groups (NGF, BDNF, bFGF, bFGF+NGF, bFGF+BDNF, NGF+BDNF and NGF+BDNF+bFGF) and a blank control group were established. One week after induction and differentiation, results showed that there was significant difference in the percentage of NSCs differentiating into neurons among the experiment groups. The percentage in the multi-factor groups was significantly higher than that in the single-factor groups (p<0.05), among which the percentage was the highest in NGF+BDNF+bFGF group. In the two-factor groups, the percentage in bFGF+NGF and bFGF+BDNF groups was significantly higher than that in NGF+BDNF group (p< 0.05). The NSCs growth curves showed that cells proliferated continuously with the time of culture prolonging, but there was significant difference between the group containing bFGF and that without bFGF. Our results demonstrate that combined use of NGF/BDNF/bFGF significantly improved the ability of NSCs proliferation and differentiation.
    International Journal of Developmental Neuroscience 08/2014; DOI:10.1016/j.ijdevneu.2014.08.002 · 2.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Organophosphorus (OP) nerve agents are deadly chemical weapons that pose an alarming threat to military and civilian populations. The irreversible inhibition of the critical cholinergic degradative enzyme acetylcholinesterase (AChE) by OP nerve agents leads to cholinergic crisis. Resulting excessive synaptic acetylcholine levels leads to status epilepticus that, in turn, results in brain damage. Current countermeasures are only modestly effective in protecting against OP-induced brain damage, supporting interest for evaluation of new ones. (-)-Phenserine is a reversible AChE inhibitor possessing neuroprotective and amyloid precursor protein lowering actions that reached Phase III clinical trials for Alzheimer's Disease where it exhibited a wide safety margin. This compound preferentially enters the CNS and has potential to impede soman binding to the active site of AChE to, thereby, serve in a protective capacity. Herein, we demonstrate that (-)-phenserine protects neurons against soman-induced neuronal cell death in rats when administered either as a pretreatment or post-treatment paradigm, improves motoric movement in soman-exposed animals and reduces mortality when given as a pretreatment. Gene expression analysis, undertaken to elucidate mechanism, showed that (-)-phenserine pretreatment increased select neuroprotective genes and reversed a Homer1expression elevation induced by soman exposure. These studies suggest that (-)-phenserine warrants further evaluation as an OP nerve agent protective strategy.
    PLoS ONE 06/2014; 9(6):e99818. DOI:10.1371/journal.pone.0099818 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Our previous studies indicated that transcription factor Brn-4 is upregulated in the surgically denervated hippocampus in vivo, promoting neuronal differentiation of hippocampal neural stem cells (NSCs) in vitro. The molecules mediating Brn-4 upregulation in the denervated hippocampus remain unknown. In this study we examined the levels of insulin-like growth factor-1 (IGF-1) in hippocampus following denervation. Surgical denervation led to a significant increase in IGF-1 expression in vivo. We also report that IGF-1 treatment on NSCs in vitro led to a marked acceleration of Brn-4 expression and cell differentiation down neuronal pathways. The promotion effects were blocked by PI3K-specific inhibitor (LY294002), but not MAPK inhibitor (PD98059); levels of phospho-Akt were increased by IGF-1 treatment. In addition, inhibition of IGF-1 receptor (AG1024) and mTOR (rapamycin) both attenuated the increased expression of Brn-4 induced by IGF-1. Together, the results demonstrated that upregulation of IGF-1 induced by hippocampal denervation injury leads to activation of the PI3K/Akt signaling pathway, which in turn gives rise to upregulation of the Brn-4 and subsequent stem cell differentiation down neuronal pathways.
    PLoS ONE 12/2014; 9(12):e113801. DOI:10.1371/journal.pone.0113801 · 3.53 Impact Factor