• Archives of Pharmacal Research
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• v.28 no.11
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• pp.1275-1281
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• 2005

The $G_{q/11}$ protein-coupled receptors, such as muscarinic (M1 & M3) receptors, have been shown to regulate the release of a soluble amyloid precursor protein (sAPP$\alpha$) produced from $\alpha$-secretase processing. However, there is no direct evidence for the precise characteristics of G proteins, and the signaling mechanism for the regulation of $G_{q/11}$ protein-coupled receptor mediated sAPP$\alpha$ release is not clearly understood. This study examined whether the muscarinic receptor-mediated release of sAPP$\alpha$ is directly regulated by $G\alpha_{q/11}$ proteins. The HEK293 cells were transiently cotransfected with muscarinic M3 receptors and a dominant-negative minigene construct of the G protein $\alpha$ subunit. The sAPP$\alpha$ release in the media was measured using an antibody specific for sAPP. The sAPP$\alpha$ release enhancement induced by muscarinic receptor stimulation was decreased by a $G_{q/11}$ minigene construct, whereas it was not blocked by a control minigene construct (the G$\alpha$ carboxy peptide in random order, G$\alpha_{q}$R) or $G\alpha_{j}$ constructs. This indicated a direct role of the $G\alpha_{q/11}$ protein in the regulation of muscarinic M3 receptor-mediated sAPP$\alpha$ release. We also investigated whether the transactivation of the epidermal growth factor receptor (EGFR) by a muscarinic agonist could regulate the sAPP$\alpha$ release in SH-SY5Y cells. Pretreatment of a specific EGFR kinase inhibitor, tyrophostin AG1478 (250 nM), blocked the EGF-stimulated sAPP$\alpha$ release, but did not block the oxoM­stimulated sAPP$\alpha$ release. This demonstrated that the transactivation of the EGFR by muscarinic receptor activation was not involved in the muscarinic receptor-mediated sAPP$\alpha$ release.

• Biomolecules & Therapeutics
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• v.27 no.3
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• pp.276-282
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• 2019

${\beta}$-amyloid precursor protein (APP) can be cleaved by ${\alpha}$-, and ${\gamma}$-secretase at plasma membrane producing soluble ectodomain fragment ($sAPP{\alpha}$). Alternatively, following endocytosis, APP is cleaved by ${\beta}$-, and ${\gamma}$-secretase at early endosomes generating ${\beta}$-amyloid ($A{\beta}$), the main culprit in Alzheimer's disease (AD). Thus, APP endocytosis is critical for $A{\beta}$ production. Recently, we reported that Monsonia angustifolia, the indigenous vegetables consumed in Tanzania, improved cognitive function and decreased $A{\beta}$ production. In this study, we examined the underlying mechanism of justicidin A, the active compound of M. angustifolia, on $A{\beta}$ production. We found that justicidin A reduced endocytosis of APP, increasing $sAPP{\alpha}$ level, while decreasing $A{\beta}$ level in HeLa cells overexpressing human APP with the Swedish mutation. The effect of justicidin A on $A{\beta}$ production was blocked by endocytosis inhibitors, indicating that the decreased APP endocytosis by justicidin A is the underlying mechanism. Thus, justicidin A, the active compound of M. angustifolia, may be a novel agent for AD treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.3
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• pp.189-195
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• 2013

Amyloid-${\beta}$ peptide ($A{\beta}$), generated by proteolytic cleavage of the amyloid precursor protein (APP), plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The key step in the generation of $A{\beta}$ is cleavage of APP by beta-site APP-cleaving enzyme 1 (BACE1). Levels of BACE1 are increased in vulnerable regions of the AD brain, but the underlying mechanism is unknown. In the present study, we reported the effects of ferrous ions at subtoxic concentrations on the mRNA levels of BACE1 and a-disintegrin-and-metalloproteinase 10 (ADAM10) in PC12 cells and the cell responses to ferrous ions. The cell survival in PC12 cells significantly decreased with 0 to 0.3 mM $FeCl_2$, with 0.6 mM $FeCl_2$ treatment resulting in significant reductions by about 75%. 4,6-diamidino-2-phenylindole (DAPI) staining showed that the nuclei appeared fragmented in 0.2 and 0.3 mM $FeCl_2$. APP-${\alpha}$-carboxyl terminal fragment (APP-${\alpha}$-CTF) associations with ADAM10 and APP-${\beta}$-CTF with BACE1 were increased. Levels of ADAM10 and BACE1 mRNA increased in response to the concentrations of 0.25 mM, respectively. In addition, p-ERK and p-Bad (S112, S155) expressions were increased, suggesting that APP-CTF formation is related to ADAM10/ BACE1 expression. Levels of Bcl-2 protein were increased, but significant changes were not observed in the expression of Bax. These data suggest that ion-induced enhanced expression of AMDA10/BACE1 could be one of the causes for APP-${\alpha}/{\beta}$-CTF activation.

• Journal of Oriental Neuropsychiatry
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• v.15 no.2
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• pp.103-118
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• 2004

Objective : This experiment was designed to investigate the effect of KongJin-dan(KJD) on the Alzheimer's disease. Method : The effects of KJD on $LI-1{\beta}$, IL-6, $TNF-{\alpha}$, amyloid precursor proteins(APP), acetylcholinesterase(AChE), glial fibrillary acidic protein(GFAP) mRNA of PC-12 and THP-1 cell treated by CT105 and AChE activity, APP production of PC-12 cell lysate treated by CT105 were investigated, respectively. Results : 1. KJD suppressed $LI-1{\beta}$, IL-6, $TNF-{\alpha}$, APP, AChE, GFAP mRNA in THP-1 and PC-12 cell treated by CT105. 2. KJD suppressed AChE activity and production of APP significantly in cell lysate of PC-12 cell treated by CT105. Conclusions : This study shows that KJD might be usefully applied for prevention and treatment of Alzheimer's disease.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.394-403
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• 2006

This research investigated the effect of the CMT and MCMT on Alzheimer's disease. The effects of the CMT and MCMT extract on expression of proinflammatory cytokine($IL-1{\beta}$, IL-6, $TNF-{\alpha}$) in the THP-1 cell; amyloid precursor proteins(APP), acetylcholinesterase(AChE) mRNA of PC-12 cells treated with CT105; the AChE activity and the APP production of PC-12 cell lysate treated with CT105 were investigated. The CMT and MCMT extract suppressed overexpression of $IL-1{\beta}$, IL-6, $TNF-{\alpha}$ in the THP-1 cell treated by LPS; the expression of APP, AChE mRNA in PC-12 cells treated with CT105; the AChE activity and the production of APP in PC-12 cell lysate treated with CT105 significantly. This study suggest that CMT and MCMT may be effective for the prevention and treatment of Alzheimer's disease.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.138-148
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• 2006

This research investigated the effect of the CMT and SCMT on Alzheimer's disease. The effects of the CMT and SCMT extract on expression of proinflammatory cytokine(IL-$1{\beta}$, IL-6, TNF-$\alpha$) in the THP-1 cell; amyloid precursor proteins(APP), acetylcholinesterase(AChE) mRNA of PC-12 cells treated with CT105; the AChE activity and the APP production of PC-12 cell lysate treated with CT105 were investigated. The CMT and SCMT extract suppressed overexpression of IL-$1{\beta}$, IL-6, TNF-$\alpha$ in the THP-1 cell treated dy LPS; the expression of APP, AChE mRNA in PC-12 cells treated with CT105; the AChE activity and the production of APP in PC-12 cell Iysate treated with CT105 significantly. This study suggest that CMT and SCMT may be effective for the prevention and treatment of Alzheimer's disease.

• Journal of Oriental Neuropsychiatry
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• v.13 no.1
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• pp.79-115
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• 2002

This research investigates the effect of the Crataegus pinnatifida BGE. var. major N.E. BR(CPVM) on Alzheimer's disease. Specifically, the effects of the DYHT extract on (1) $IL-1{\beta}$, IL-6, amyloid precursor proteins(APP), acetylcholinesterase(AChE), and glial fibrillary acidic protein(GFAP) mRNA of PC-12 cells treated with CTI05; (2) the AChE activity and the APP production of PC-12 cell treated with CT105; (3) the behavior; and (4) expression of $IL-1{\beta}$, $TNF-{\alpha}$, reactive oxygen species(ROS), nitrite oxide(NO); and (5) the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with CT105 were investigated. The results are as follow. 1. The CPVM extract suppressed the expression of $IL-1{\beta}$, IL-6, APP, AChE, and GFAP mRNA in PC-12 cells treated with CT105. 2. The CPVM extract suppressed the AChE activity and the production of APP significantly in PC-12 cells treated with CT105. 3. The CPVM extract group showed a significant inhibitory effect on the memory deficit for the mice with Alzheimer's disease induced by CT105 in the Morris water maze experiment. 4. The CPVM extract suppressed the over-expression of $IL-1{\beta}$, $TNF-{\alpha}$, ROS and NO in the mice with Alzheimer's disease induced by CT105. 5. The CPVM extract reduced the infarction area of hippocampus, and controlled the injury of brain tissue in the mice with Alzheimer's disease induced by CT105. These results suggest that the CPVM extract may be effective for the prevention and treatment of Alzheimer's disease.

• Journal of Oriental Neuropsychiatry
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• v.17 no.2
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• pp.91-122
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• 2006

Objective : This research investigates the effect of the Jangwon-Dan,(JWD) on Alzheimer's disease. Method : The effects of the JWN extract on (1) $IL-1{\beta}$, IL-6, and $TNF-{\alpha}$ mRNA of PC-12 cells treated with LPS; (2) amyloid precursor proteins(APP), acetylcholinesterase(AChE), and glial fibrillary acidic protein(GFAP) mRNA, the AChE activity and the APP production of PC-12 cell treated with CT-105; (3) the behavior; (4) expression of $IL-1{\beta}$, $TNF-{\alpha}$, MDA, $IL-1{\beta}$ mRNA, and $TNF-{\alpha}$ mRNA, (5) the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with ${\beta}A$ were investigated. Result : 1. The JWN extract suppressed the expression of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ mRNA in THP-1 cells treated with LPS. 2. The JWN extract suppressed the expression of APP, AChE, and GFAP mRNA in PC-12 cells treated with CT-105. 3. The JWN extract suppressed the AChE activity, and the production of APP significantly in PC-12 cells treated with CT-105. 4. For the JWN extract group a significant inhibitory effect on the memory deficit was shown for the mice with Alzheimer's disease induced by ${\beta}A$ in the Morris water maze experiment, which measured stop-through latency, and distance movement-through latency. 5. The JWN extract suppressed the over-expression of $IL-1{\beta}$ protein, $TNF-{\alpha}$ protein, MDA, $IL-1{\beta}$ mRNA, $TNF-{\alpha}$ mRNA, and CD68/GFAP, in the mice with Alzheimer's disease induced by ${\beta}A$. 6. The JWN extract reduced the infarction area of hippocampus, and controlled the injury of brain tissue in the mice with Alzheimer's disease induced by ${\beta}A$. Conclusion : These results suggest that the JWN extract may be effective for the prevention and treatment of Alzheimer's disease. Investigation into the clinical use of the JWN extract for Alzheimer's disease is suggested for future research.

• Journal of Oriental Neuropsychiatry
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• v.16 no.1
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• pp.97-117
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• 2005

This research investigates the effect of the Chaenomelis fructus(CMF) on Alzheimer's disease. Specifically, the effects of the CMF extract on (1) >$IL-1{\beta}$, IL-6, and $TNF-{\alpha}$ mRNA of PC-12 cells treated with LPS; (2) amyloid precursor proteins(APP), acetylcholinesterase(AChE), and glial fibrillary acidic protein(GFAP) mRNA of PC-12 cells treated with CT-105; (3) the AChE activity and the APP production of PC-12 cell treated with CT-105; (4) the behavior of AD mice with ${\beta}A$; (5) expression of $IL-1{\beta}$, $TNF-{\alpha}$, MDA, $IL-1{\beta}$ mRNA, $TNF-{\alpha}$ mRNA, and ROS; (6) the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with ${\beta}A$ were investigated. The results were summarized as follows; 1. The CMF extract suppressed the expression of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ mRNA in THP-1 cells treated with LPS. 2. The CMF extract suppressed the expression of APP, AChE, and GFAP mRNA in PC-12 cells treated with CT-105. 3. The CMF extract suppressed the AChE activity, and the production of APP significantly in PC-12 cells treated with CT-105. 4. A significant inhibitory effect on the memory deficit was shown on the CMF extract group of the mice with Alzheimer's disease induced by ${\beta}A$ in the Morris water maze experiment, which measured stop-through latency, and distance movement-through latency. 5. The CMF extract suppressed the over-expression of $IL-1{\beta}$ protein, $TNF-{\alpha}$ protein, MDA, $IL-1{\beta}$ protein, mRNA, $TNF-{\alpha}$ mRNA, CD68/GFAP, and ROS in the mice with Alzheimer's disease induced by ${\beta}A$. 6. The CMF extract reduced the infarction area of hippocampus, and controlled the injury of brain tissue in the mice with Alzheimer’s disease induced by ${\beta}A$. These results suggest that the CMF extract may be effective for the treatment of Alzheimer’s disease. Investigation into the clinical use of the CMF extract for Alzheimer's disease is suggested for future research.

• Journal of Oriental Neuropsychiatry
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• v.15 no.2
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• pp.119-139
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• 2004

This research investigates the effect of the Hibiscus syriacus(HSS) on Alzheimer's disease. Specifically, the effects of the HSS extract on (1) $IL-1{\beta}$, IL-6, and $TNF-{\alpha}$ mRNA of PC-12 cells treated with LPS; (2) amyloid precursor proteins(APP), acetylcholinesterase(AChE), and glial fibrillary acidic protein(GFAP) mRNA of PC-12 cells treated with CT-105; (3) the AChE activity and the APP production of PC-12 cell treated with CT-105; (4) the behavior; (4) expression of $IL-1{\beta}$, $TNF-{\alpha}$, $IL-1{\beta}$ mRNA, $TNF-{\alpha}$ mRNA, and reactive oxygen species(ROS); (5) the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with ${\beta}A$ were investigated. The results were summarized below ; 1. The HSS extract suppressed the expression of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ mRNA in THP-l cells treated with LPS. 2. The HSS extract suppressed the expression of APP, AChE, and GFAP mRNA in PC-12 cells treated with CT-105. 3. The HSS extract suppressed the AChE activity, and the production of APP significantly in PC-12 cells treated with CT-105. 4. For the HSS extract group a significant inhibitory effect on the memory deficit was shown for the mice with Alzheimer's disease induced by ${\beta}A$ in the Morris water maze experiment, which measured stop-through latency, and distance movement-through latency. 5. The HSS extract suppressed the over-expression of $IL-1{\beta}$, $TNF-{\alpha}$, $IL-1{\beta}$ and $TNF-{\alpha}$ mRNA, CD68/GFAP, ROS in the mice with Alzheimer's disease induced by ${\beta}A$. 6. The HSS extract reduced the infarction area of hippocampus, and controlled the injury of brain tissue in the mice with Alzheimer's disease induced by ${\beta}A$. These results suggest that the HSS extract may be effective for the prevention and treatment of Alzheimer's disease. Investigation into the clinical use of the HSS extract for Alzheimer's disease is suggested for future research.