Yokukansan, a Kampo medicine, enhances the level of neuronal lineage markers in differentiated P19 embryonic carcinoma cells

Impact of Plasma Donepezil Concentration on Behavioral and Psychological Symptoms of Dementia in Patients with Alzheimer’s Disease

Background/Aims

The behavioral and psychological symptoms of dementia (BPSD) detract from the quality of life of not only dementia patients but also their family members and caregivers. Donepezil is used to treat Alzheimer's disease and is metabolized via cytochrome P450 (CYP) 2D6 and CYP3A4/5. It is controversial whether donepezil improves or exacerbates BPSD. This study investigated the relationships among BPSD, the pharmacokinetics of donepezil including its metabolite, 6-O-desmethyl donepezil, genetic polymorphisms of CYPs and P-glycoprotein, and patient backgrounds in 52 patients with Alzheimer's disease.

Methods

BPSD were assessed using the Neuropsychiatric Inventory (NPI), with scores ≥20 points defined as severe BPSD. Plasma donepezil and 6-O-desmethyl donepezil concentrations were measured using liquid chromatography–tandem mass spectrometry.

Results

Although significant relationships between NPI scores and plasma donepezil concentrations were not seen, none of the 15 patients (29%) with high plasma donepezil concentrations (≥60 ng/mL) developed severe BPSD. Polymorphisms of CYP2D6, CYP3A5, and ABCB1 did not influence NPI scores. There were no significant relationships between NPI and patient background factors such as dosing regimen, concomitant use of other drugs, or laboratory test results. Two patients who underwent multiple blood samplings over 2 years showed an inverse correlation between plasma donepezil concentrations and NPI scores.

Discussion/Conclusions

These results indicate that higher plasma concentrations of donepezil contribute to preventing or alleviating rather than developing or deteriorating BPSD.

Zinc finger protein 483 (ZNF483) regulates neuronal differentiation and methyl-CpG-binding protein 2 (MeCP2) intracellular localization

Rett syndrome (OMIM #312750) is a developmental neurological disorder that is caused by a mutation in methyl-CpG-binding protein 2 (MeCP2). MeCP2 localizes to the nucleus, binds to methylated DNA, and regulates gene expression during neuronal development. MeCP2 assembles multiple protein complexes and its functions are controlled by interactions with its binding partners. Therefore, functional analysis of MeCP2 binding proteins is important. Previously, we proposed nine MeCP2-binding candidates in the cerebral cortex. In this study, we characterized and examined the function of the MeCP2 binding protein zinc finger protein 483 (ZNF483) to determine the significance of the MeCP2-ZNF483 interaction in neuronal development. Phylogenetic profiling revealed that the ZNF483 protein is broadly conserved in metazoans. In contrast, MeCP2 was obtained during evolution to chordates. To investigate ZNF483 functions, ZNF483-knockout P19 cell lines were established using the CRISPR-Cas9 system. These cell lines showed decreased cell proliferation, altered aggregate formation, decreased neuronal marker NeuN expression, and altered MeCP2 phosphorylation patterns. Notably, cytosolic localization of MeCP2 was enhanced by ZNF483-overexpression. Taken together, we propose that ZNF483 might be involved in the promotion of neuronal differentiation by regulating the subcellular localization of MeCP2 in P19 cells.

Establishment of a Simple Method for Inducing Neuronal Differentiation of P19 EC Cells without Embryoid Body Formation and Analysis of the Role of Histone Deacetylase 8 Activity in This Differentiation

P19 pluripotent embryonic carcinoma (EC) stem cells are derived from pluripotent germ cell tumours and can differentiate into three germ layers. Treatment of these cells in suspension culture with retinoic acid induces their differentiation into neurons and glial cells. Hence, these cells are an excellent in vitro model to study the transition from the upper blastoderm to the neuroectoderm. However, because of the complex nature of the techniques involved, the results are highly dependent on the skills of the experimenter. Herein, we developed a simple method to induce neuronal differentiation of adherent P19 EC cells in TaKaRa NDiff^® 227 serum-free medium (originally N2B27 medium). This medium markedly induced neuronal differentiation of P19 EC cells. The addition of retinoic acid to the NDiff^® 227 medium further enhanced differentiation. Furthermore, cells differentiated by the conventional method, as well as the new method, showed identical expression of the mature neuronal marker, neuronal nuclei. To determine whether our approach could be applied for neuronal studies, we measured histone deacetylase 8 (HDAC8) activity using an HDAC8 inhibitor and HDAC8-knockout P19 EC cells. Inhibition of HDAC8 activity suppressed neuronal maturation. Additionally, HDAC8-knockout cell lines showed immature differentiation compared to the wild-type cell line. These results indicate that HDAC8 directly regulates the neuronal differentiation of P19 EC cells. Thus, our method involving P19 EC cells can be used as an experimental system to study the nervous system. Moreover, this method is suitable for screening drugs that affect the nervous system and cell differentiation.