• KSBB Journal
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• v.28 no.4
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• pp.230-237
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• 2013

Amyloid ${\beta}$ peptide (A${\beta}$) still best known as a molecule to cause Alzheimer's disease (AD). AD is characterized by the accumulation and deposition of A${\beta}$ within the brain, leading to neuronal cell loss and perturbation of synaptic function by causing free radical formation, inflammation and apoptosis. We investigated the inflammatory action of A${\beta}$ on two types of brain cells, neuronal cells (SH-SY5Y) and neuroglia cells (C6), and its mechanism. We measured the production of NO-iNOS, TNF-${\alpha}$, and ICAM-1 using RT-PCR and Western blot analysis less than the concentration of cytotoxic effects (> 70% survivability). A${\beta}$ had no effect on the production of NO and TNF-${\alpha}$, but significantly increases of iNOS and ICAM-1. Based on this, we suggest that the inflammatory effect of A${\beta}$ results from the action of ICAM-1 in neuronal cells, rather than the release of inflammatory mediators such as NO and TNF-${\alpha}$ in neuroglia cells. In addition, we confirmed whether p53 was related to the action of A${\beta}$ by using SH-SY5Y ($p53^{-/-}$) dominant cells. Neither the expression of p53 nor the cytotoxicity of SH-SY5Y ($p53^{-/-}$) cells were directly affected by A${\beta}$. However, ICAM-1 was not expressed in SH-SY5Y ($p53^{-/-}$) cells. This means that p53- independent pathway exists in the expression of ICAM-1 by A${\beta}$ while p53 plays a role as an on-and-off switch.

• BMB Reports
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• v.44 no.11
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• pp.730-734
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• 2011

Amyloid ${\beta}$-peptide ($A{\beta}$-peptide)-induced oxidative stress is thought to be a critical component of the pathophysiology of Alzheimer's disease (AD). New chalcone derivatives, the Chana series, were recently synthesized from the retrochalcones of licorice. In this study, we investigated the protective effects of the Chana series against neurodegenerative changes in vitro and in vivo. Among the Chana series, Chana 30 showed the highest free radical scavenging activity (90.7%) in the 1,1-diphenyl-2- picrylhydrazyl assay. Chana 30 also protected against $A{\beta}$-induced neural cell injury in vitro. Furthermore, Chana 30 reduced the learning and memory deficits of $A{\beta}_{1-42}$-peptide injected mice. Taken together, these results suggest that Chana 30 may be a promising candidate as a potent therapeutic agent against neurodegenerative diseases.

• BMB Reports
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• v.32 no.6
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• pp.561-566
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• 1999

CA(1-8)-ME(1-12) [CA-ME], composed of cecropin A(1-8) and melittin(1-12), is a synthetic antimicrobial peptide having potent antibacterial and antitumor activities with minimal hemolytic activity. In order to investigate the effects of the flexible hinge sequence, Gly-Ile-Gly, of CA-ME on antibiotic activity, CA-ME and three analogues, CA-ME1, CA-ME2, and CA-ME3, were synthesized. The Gly-Ile-Gly sequence of Ca-ME was deleted in CA-ME1 and replaced with Pro and Gly-Pro-Gly in CA-ME2 and CA-ME3, respectively. CA-ME1 and CA-ME3 showed a significant decrease in antitumor activity and phospholipid vesicle-disrupting ability. However, CA-ME2 showed similar antitumor and vesicle-disrupting activities, as compared with CA-ME. These results suggest that the flexibility or ${\beta}$-turn induced by Gly-Ile-Gly or Pro in the central part of CA-ME may be important in the electrostatic interaction of the N-terminus cationic ${\alpha}$-helical region with the cell membrane surface and the hydrophobic interaction of the C-terminus amphipathic ${\alpha}$-helical region with the hydrophobic acyl chains in the cell membrane. CA-ME3 exhibited lower antitumor and vesicle-disrupting activities than CA-ME and CA-ME2. This result suggests that the excessive ${\beta}$-turn structure caused by the Gly-Pro-Gly sequence in CA-ME3 seems to interrupt ion channel/pore formation in the lipid bilayer. We concluded that the appropriate flexibility or bilayer. We concluded that the appropriate flexibility or ${\beta}$-turn structure provided by the central hinge is responsible for the effective antibiotic activity of the antimicrobial peptides with the helix-hinge-helix structure.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.86-86
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• 1995

The analysis of membrane receptors for hormones and neurotransmitters has progressed considerably by pharmacological and biochemical means and more recently by the use of specific anti-receptor antibodies. A 14-mer peptide (from Phe102 to Leu115 of ${\beta}$2-adrenergic receptor) was synthesized and this peptide was coupled to carrier protein Keyhole Limpet Hemocyanin(KLH) by glutaraldehyde method. A 0.5mg of KLH-coupled peptide was emulsified with equal volume of complete Freund's adjuvant and injected via popliteal lymph node to each of the three Newzealnd White rabbits. Booster injections were repeated at 4 weeks interval for three times with incomplete Freund's adjuvants. One week after the final injection, serum was prepared from ear artery. Nonspecific immunoglobulins were removed by passing the serum through KLH-Sepharose 6B affinity matrix and further by incubation with bovine lung aceton powder. The titer of the antibody for synthetic peptide which was determined by enzyme linked immunosorbent assay(ELISA) was about l/l,000. The antibody produced in this study revealed 67kDa protein band in the western blot of partially purified guinea pig lung ${\beta}$-adrenergic receptor preparation. The antibody inhibited ${\beta}$-adrenergic antaginist [3H] Dihydroalprenolol binding to soluble ${\beta}$-adrenergic receptor by 25% while control sera did not show any inhibitory effects, The result of this study suggests that the peptide sequence selected in this study may play some important roles in adrenergic receptor-ligand interaction.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.04a
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• pp.77-90
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• 2006

Beta-amyloid peptide (A$\beta$) is a major component of senile plaques and its aggregation is considered to play a critical role in pathogenesis of Alzheimer's disease (AD). Aggregation of A$\beta$ could result from both increased synthesis and decreased degradation of A$\beta$. Our laboratory is interested in understanding the mechanism of A$\beta$ degradation in brain. Recently our laboratory identified a bacterial gene (SKAP) from Streptomyces sp KK565 whose protein product has an activity to cleave A$\beta$ and thus reduce the A$\beta$-induced neurotoxicity. The sequence analysis showed that this gene was closely related to aminopeptidase. Maldi-Tof analysis showed that the recombinant SKAP protein expressed in E. coli cleaves both A$\beta$ 40 and A$\beta$ 42 at the N-terminal of A$\beta$ while an aminopeptidase from Streptomyces griseus (SGAP) cleaves at the C-terminal. We also identified a mammalian homolog of SKAP and the recombinant mammalian protein expressed in Sf-9 insect cells showed a similar proteolytic activity to SGAP, cutting A$\beta$ at the C-terminus. I well discuss the detailed mechanism of the enzyme action and its functional implication in AD.

• BMB Reports
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• v.42 no.11
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• pp.737-742
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• 2009

Hypoxia-inducible factor-$1{\alpha}/{\beta}$ (HIF-$1{\alpha}/{\beta}$) is a heterodimeric transcriptional activator that mediates gene expression in response to hypoxia. HIF-$1{\alpha}$ has been noted as an effective therapeutic target for ischemic diseases such as myocardiac infarction, stroke and cancer. By using a yeast two-hybrid system and a random peptide library, we found a 16-mer peptide named F29 that directly interacts with the bHLH-PAS domain of HIF-$1{\alpha}$. We found that F29 facilitates the interaction of the HIF-$1{\alpha/\beta}$ heterodimer with its target DNA sequence, hypoxia-responsive element (HRE). The transient transfection of an F29-expressing plasmid increases the expression of both an HRE-driven luciferase gene and the endogenous HIF-1 target gene, vascular endothelial growth factor (VEGF). Taken together, we conclude that F29 increases the DNA-binding ability of HIF-$1{\alpha}$, leading to increased expression of its target gene VEGF. Our results suggest that F29 can be a lead compound that directly targets HIF-$1{\alpha}$ and increases its activity.

• IMMUNE NETWORK
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• v.5 no.3
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• pp.157-162
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• 2005

Background: 1-8D gene is a member of human 1-8 interferon inducible gene family and was shown to be overexpressed in fresh colon cancer tissues. Three peptides 1-6, 3-5 and 3-7 derived from human 1-8D gene were shown to have immunogenicity against colon cancer. Methods: To study tumor immunotherapy, of three peptides we established an active immunization model using HHD mice. $D^{b-/-}{\times}{\beta}2$ microglobulin $({\beta}2m)$ null mice transgenic for a chimeric HLA-$A2.1/D^{b-}\;{\beta}2m$ single chain (HHD mice) were challenged with B16/HHD/1-8D tumor cells and were immunized with irradiated peptide-loaded RMA- S/HHD/B7.1 transfectants. In therapy model tumor growth was retarded in HHD mice that were injected with 3-5 peptide-loaded RMA-S/HHD/B7.1. In survival test vaccination with 1-8D-derived peptide protects HHD mice from tumor progression after tumor challenge. Results: These studies show that peptide 3-5 derived from 1-8D gene can be the most effective candidate for the vaccine of immunotherapy against colon cancer and highlight 1-8D gene as putative colon carcinoma associated antigens. Conclusion: We demonstrated that RMA-S/HHD/ B7.1 loaded with 1-8D peptides, especially 3-5, immunization generates potent antitumor immunity against tumor cells in HHD mice and designed active immunization as proper immunotherapeutic protocols.

• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.251-258
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• 2008

The neurotoxicity of C-terminal fragments of amyloid precusor protein (CT) is known to play some roles in Alzheimer's disease progression. In this study, we investigated the effects of the recombinant C-terminal 105 amino acid fragment of amyloid precusor protein (CT105) on cholinergic function using CT105-injected rat. To study the effects of CT105 on septohippocampal pathway, choline acetyltransferase (ChAT) positive neurons were examined in the medial septum and in the diagonal band after an injection of CT105 peptide into the lateral ventricle. Immunohistological analysis revealed that the number of ChAT-immunopositive cells decreased significantly in both medial septum and diagonal band. In addition, CT105 decreased ChAT-immunopositive cells in the hippocampal area, particulary in the dentate gyros. To study the effect of amyloid beta peptide ($A{\beta}$) and CT105 on the cholinergic system, each peptide was injected into the left lateral ventricle, and acetylcholine (ACh) levels were monitored in hippocampus. ACh level in the hippocampal area was reduced to 60% of control level in $A{\beta}$-treated group, and the level was reduced to 15% of control level in CT105-treated group, at one week after the injection. ACh level was further reduced to 35% of control in $A{\beta}$-treated group, whereas the level was slightly increased to 30% of control in CT105-treated group at 4 weeks after the injection. Taken together, the results in the present study suggest that CT105 impairs the septohippocampal pathway by reducing acetylcholine synthesis and release, which results in damage of learning and memory.

• Molecules and Cells
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• v.40 no.9
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• pp.613-620
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• 2017

The most common form of senile dementia is Alzheimer's disease (AD), which is characterized by the extracellular deposition of amyloid ${\beta}-peptide$ ($A{\beta}$) plaques and the intracellular formation of neurofibrillary tangles (NFTs) in the cerebral cortex. Tau abnormalities are commonly observed in many neurodegenerative diseases including AD, Parkinson's disease, and Pick's disease. Interestingly, tau-mediated formation of NFTs in AD brains shows better correlation with cognitive impairment than $A{\beta}$ plaque accumulation; pathological tau alone is sufficient to elicit frontotemporal dementia, but it does not cause AD. A growing amount of evidence suggests that soluble $A{\beta}$ oligomers in concert with hyperphosphorylated tau (pTau) serve as the major pathogenic drivers of neurodegeneration in AD. Increased $A{\beta}$ oligomers trigger neuronal dysfunction and network alternations in learning and memory circuitry prior to clinical onset of AD, leading to cognitive decline. Furthermore, accumulated damage to mitochondria in the course of aging, which is the best-known nongenetic risk factor for AD, may collaborate with soluble $A{\beta}$ and pTau to induce synapse loss and cognitive impairment in AD. In this review, I summarize and discuss the current knowledge of the molecular and cellular biology of AD and also the mechanisms that underlie $A{\beta}-mediated$ neurodegeneration.

• Journal of Pharmaceutical Investigation
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• v.41 no.2
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• pp.91-94
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• 2011

The purpose of this study was to investigate the effect of peptide charge on the interaction between peptide and poly(D,L-lactide-co-glycolide) (PLGA) for evaluating mechanism of acylated peptide formation in PLGA matrix. As a model peptide, octreotide, a synthetic somatostatin analogue and active ingredient of commercial PLGA product, was used. The disulfide group of octreotide was reduced with dithiothreitol and the sulfhydryl groups were modified with N-${\beta}$-maleimidopropionic acid (BMPA) to neutralize octreotide with positive charge in physiological conditions. The BMPA-conjugated octreotide was identified by measuring the molecular mass with liquid chromatography-mass spectrometry. In the interaction study with PLGA, native octreotide showed initial adsorption to PLGA and substantial production of acylated peptides (56% of overall peptide), whereas BMPA-conjugated octreotide showed minimal adsorption to PLGA and no acylation products for 42 days. Consequently, the neutralization of octreotide completely inhibited the peptide acylation by preventing interaction of peptide with PLGA. In conclusion, this study demonstrates that the initial polymer interaction of peptide is important step for peptide acylation in PLGA matrix and suggests the modulation of peptide charge as strategy for inhibiting the formation of acylated peptide impurities.