• Applied Microscopy
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• v.42 no.4
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• pp.179-185
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• 2012

Alzheimer's disease (AD) is a progressive neurodegenerative disorder. Neuropathological hallmarks of AD are amyloid plaques, dystrophic neurite, and alteration of subcellular organelles. However, the morpho-functional study of this degenerative process and ultimate neuronal death remains poorly elucidated. In this study, immunohistochemical and ultrastructural analyses were performed to clarify the abnormal morphological alterations caused by the progression of AD in APP/PSEN1 transgenic mice, express human amyloid precursor protein, as a model for AD. In transgenic AD mice brain, the accumulation of Amyloid ${\beta}$ plaques and well-developed dystrophic neurites containing anti-LC3 antibody-positive autophagosomes were detected in the hippocampus and cortex regions. We also found severe disruption of mitochondrial cristae using high-voltage electron microscopy and three-dimensional electron tomography (3D tomography). These results provide morpho-functional evidence on the alteration of subcellular organelles in AD and may help in the investigation of the pathogenesis of AD.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.202.1-202.1
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• 2003

Microglial cell can act for phagocytosis against abnormal particles in brain, which means that beta-amyloid produced from APP(amyloid precursor protein) can be phagocytosed by microglia when released. In contrast. when senile plaque has already been formed in brain cortex and hippocamphal region, microglia can also accelerate the AD pathogenesis due to chronic inflammatory action, which lead to neuron cell cytotoxicity. (omitted)

• BMB Reports
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• v.50 no.7
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• pp.345-354
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• 2017

Autophagy, a catabolic process necessary for the maintenance of intracellular homeostasis, has recently been the focus of numerous human diseases and conditions, such as aging, cancer, development, immunity, longevity, and neurodegeneration. However, the continued presence of autophagy is essential for cell survival and dysfunctional autophagy is thought to speed up the progression of neurodegeneration. The actual molecular mechanism behind the progression of dysfunctional autophagy is not yet fully understood. Emerging evidence suggests that basal autophagy is necessary for the removal of misfolded, aggregated proteins and damaged cellular organelles through lysosomal mediated degradation. Physiologically, neurodegenerative disorders are related to the accumulation of amyloid ${\beta}$ peptide and ${\alpha}-synuclein$ protein aggregation, as seen in patients with Alzheimer's disease and Parkinson's disease, respectively. Even though autophagy could impact several facets of human biology and disease, it generally functions as a clearance for toxic proteins in the brain, which contributes novel insight into the pathophysiological understanding of neurodegenerative disorders. In particular, several studies demonstrate that natural compounds or small molecule autophagy enhancer stimuli are essential in the clearance of amyloid ${\beta}$ and ${\alpha}-synuclein$ deposits. Therefore, this review briefly deliberates on the recent implications of autophagy in neurodegenerative disorder control, and emphasizes the opportunities and potential therapeutic application of applied autophagy.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.408-415
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• 2023

Alzheimer's disease constitutes a large proportion of all neurodegenerative diseases and is mainly caused by excess aggregation of amyloid beta (Aβ), which results in oxidative stress, inflammation, and apoptosis in the neurons. Populus tomentiglandulosa belongs to the Salicaceae family and is widely distributed in Korea; the antioxidant activities of the extract and fractions from P. tomentiglandulosa have been demonstrated in previous studies. Specifically, the ethyl acetate (EtOAc) fraction of P. tomentiglandulosa (EtOAc-PT) shows the most powerful antioxidative activity. Therefore, the present study investigates the protective effects of EtOAc-PT against neuronal damage in Aβ_25-35-stimulated SH-SY5Y cells. EtOAc-PT restored cell viability significantly as well as inhibited the levels of reactive oxygen species and lactate dehydrogenase release compared to the Aβ_25-35-induced control group. Furthermore, the inflammation- and apoptosis-related protein expressions were investigated to demonstrate its neuroprotective mechanism. EtOAc-PT downmodulated the expressions of inducible nitric oxide synthase, cyclooxygenase-2, B-cell lymphoma 2 associated X, and B-cell lymphoma 2. Thus, the findings show that EtOAc-PT has protective effects against Aβ_25-35 by suppressing oxidative stress, inflammation, and apoptosis.

• Journal of Korean Neurosurgical Society
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• v.39 no.6
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• pp.447-450
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• 2006

Cerebral amyloid angiopathy[CAA] is characterized by the deposition of amyloid ${\beta}-protein$ in the walls of small to medium-sized arteries of the leptomeninges and cerebral cortex. While often asymptomatic, CAA can develop into intracerebral hemorrhage facilitated by arterial hypertension. We report the case of a 52-year-old man with CAA and arterial hypertension who developed recurrent cerebral hemorrhages on three different occasions and in multiple non-overlapping loci over a period of nine years. Based on our findings, we recommend brain biopsies for all patients undergoing evacuation of multiple recurrence or atypical pattern intracerebral hemorrhages.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1165-1170
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• 2008

The deposition of the amyloid $\beta}$ ($A{\beta}$)-peptide following proteolytic processing of amyloid precursor protein (APP) by $\beta$-secretase (BACE1) and $\gamma$-secretase is critical feature in the progress of Alzheimer's disease (AD). Consequently, BACE1, a key enzyme in the production of $A{\beta}$, is a prime target for therapeutic intervention in AD. In the course of searching for BACE1 inhibitors from natural sources, the ethyl acetate fraction of Petasites japonicus showed potent inhibitory activity. Two BACE1 inhibitors quercetin (QC) and kaempferol 3-O-(6"-acetyl)-$\beta$-glucopyranoside (KAG) were isolated from P. japonicus by activity-guided purification. QC, in particular, non-competitively attenuated BACE1 activity with $IC_{50}$ value of $2.1{\times}10^{-6}\;M$ and $K_i$ value of $3.7{\times}10^{-6}\;M$. Both compounds exhibited less inhibition of $\alpha$-secreatase (TACE) and other serine proteases including chymotrypsin, trypsin, and elastase, suggesting that they ere relatively specific and selective inhibitors to BACE1. Furthermore, both compounds significantly reduced the extracellular $A{\beta}$ secretion in $APP_{695}$-transfected B103 cells.

• BMB Reports
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• v.43 no.10
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• pp.704-709
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• 2010

The Swedish mutation (K595N/M596L) of amyloid precursor protein (APP-swe) has been known to increase abnormal cleavage of cellular APP by Beta-secretase (BACE), which causes tau protein hyperphosphorylation and early-onset Alzheimer's disease (AD). Here, we analyzed the effect of APP-swe in global gene expression using deep transcriptome sequencing technique. We found 283 genes were down-regulated and 348 genes were up-regulated in APP-swe expressing H4-swe cells compared to H4 wild-type cells from a total of approximately 74 million reads of 38 base pairs from each transcriptome. Two independent mechanisms such as kinase and phosphatase signaling cascades leading hyperphosphorylation of tau protein were regulated by the expression of APP-swe. Expressions of catalytic subunit as well as several regulatory subunits of protein phosphatases 2A were decreased. In contrast, expressions of tau-phosphorylating glycogen synthase kinase $3\beta$(GSK-3$\beta$), cyclin dependent kinase 5 (CDK5), and cAMP-dependent protein kinase A (PKA) catalytic subunit were increased. Moreover, the expression of AD-related Aquaporin 1 and presenilin 2 expression was regulated by APP-swe. Taken together, we propose that the expression of APP-swe modulates global gene expression directed to AD pathogenesis.

• Journal of Acupuncture Research
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• v.23 no.2
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• pp.33-46
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• 2006

Alzheimer's disease (AD) is the most prevalent form of neurodegenerative disease associated with aging in the human population. This disease is characterized by the extracellular deposition of beta-amyloid peptide $(A{\beta})$ in cerebral plaques. $A{\beta}$ is derived from the ${\beta}-amyloid$ precursor protein (APP) by the enzymes, ${\beta}-$ and ${\eta}o-secretase$. Compounds that ${\beta}-$ or ${\eta}o-secretase$ inhibit activity, can reduce the production of $A{\beta}$ peptides, and thus have therapeutic potential in the treatment of AD. Increasing body of evidence has been demonstrated that Bee Venom(BV) Acupuncture could compete with complex protein involving in multiple step of $NF-{\kappa}B$ activation and exert the anti-inflammatory potential of combined inhibition of the prostanoid and nitric oxide synthesis systems by inhibition of IKK and $NF-{\kappa}B$. In this study, I investigated possible effects of BV on memory dysfunction caused by lipopolysaccharide (LPS) and $A{\beta}$ through inhibition of secretases activities and $A{\beta}$ aggregation. I examined the improving effect of BV on the LPS (2.5 mg/Kg, i.p.)-induced memory dysfunction using passive avoidance response and water maze tests in the mice. BV (0.84, $1.67\;{\mu}g/ml$) reversed the LPS-induced memorial dysfunction in dose dependent manner. BV also dose-dependently attenuated LPS-induced ${\beta}$ and ${\eta}o-secretase$ activities in cerebral cortex and hippocampus of the mice brain. This study therefore suggests that BV acupuncture method may be useful for prevention of development or progression of AD.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.105-112
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• 2021

Excessive accumulation of the amyloid beta (Aβ) peptide has been implicated in the pathogenesis of Alzheimer's disease (AD). Paeonia lactiflora (PL) has been used in treatments of several conditions such as inflammation, arthritis, and cognitive impairment. The purpose of this study was to investigate the neuroprotective effect and mechanisms of PL and its active compound, paeoniflorin (PF), on Aβ_25-35-induced neurotoxicity in SH-SY5Y cells. We evaluated cell viability, lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) production. Furthermore, underlying mechanism of PL and PF on the regulation of amyloidogenic pathway was analyzed by Western blotting. In our results, Aβ_25-35-induced neuronal cell loss was observed, whereas treatment with PL (10, 50, and 100 ㎍/mL) and PF (1, 5, and 10 ㎍/mL) significantly elevated the cell viability, and decreased LDH release and ROS production. In addition, exposure of SH-SY5Y cells to Aβ_25-35 significantly increased the protein levels of amyloid precursor protein (APP)-C-terminal fragment β, β-site APP-cleaving enzyme, and presenilin-1 and -2. However, treatment with PL and PF inhibited the amyloidogenic pathway via the down-regulation of those protein expressions. Taken together, our results indicate that PL, and its active compound PF, could protect SH-SY5Y cells against Aβ_25-35-induced cell neurotoxicity by attenuating LDH release and ROS production, and these effects may be attributed to regulation of amyloidogenic pathway-related protein expression. In conclusion, PL and PF could be a potential to prevent neurodegenerative disorders such as AD.

• The Journal of Korean Medicine
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• v.29 no.2
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• pp.151-164
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• 2008

Objective: To investigate the effects of Yeongdamsagantang (YDGT) on apoptosis of neuronal cells that can result in dementia. Method: The water extract of the YDGT was tested in vitro for its beneficial effects on neuronal survival and neuroprotective functions, particularly in connection with $A{\beta}$ oligomer-related dementias. $A{\beta}$ oligomers derived from proteolytic processing of the ${\beta}-amyloid$ precursor protein (APP), including the $amyloid-{\beta}$ peptide $(A{\beta})$, play a critical role in the pathogenesis of Alzheimer's disease. A neuroblastoma cell line stably expressing an $A{\beta}$ oligomerassociated neuronal degeneration was used to investigate if YDGT inhibits formation of $A{\beta}$ oligomer. To measure the ATP generating level in mitochondrial membrane, luciferin/luciferase luminescence kit (Promega) and luminator was used, and to survey the protein's apparition, confocal microscopy was used. Result: $A{\beta}oligomer$ had a profound attenuation in the increase in CT105 expressing neuro2A cells from YDGT. Experimental evidence indicates that YDGT protected against neuronal damage from cells, but its cellular and molecular mechanisms remain unknown. We demonstrated that YDGT inhibited formation of $amyloid-{\beta}$ $(A{\beta})$ oligomers, which were the behavior, and possibly causative, features of AD. The decreased $A{\beta}$ oligomer in the presence of YDGT was observed in the conditioned medium of this $A{\beta}oligomer-secreting$ cell line under in vitro. In the cells, YDGT significantly attenuated mitochondrion-initiated apoptosis. Conclusion: (i) a direct $A{\beta}$ oligomer toxicity and the apoptosis initiated by the mitochondria; and (ii) multiple cellular and molecular neuroprotective mechanisms, including attenuation of apoptosis and direct inhibition of $A{\beta}$ oligomer aggregation, underlie the neuroprotective effects of YDGT.