• IMMUNE NETWORK
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• 제10권3호
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• pp.99-103
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• 2010

Background: Glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$) is a ubiquitous serine/threonine kinase that is regulated by serine phosphorylation at 9. Recent studies have reported the beneficial effects of a number of the pharmacological $GSK3{\beta}$ inhibitors in rodent models of septic shock. Since most of the $GSK3{\beta}$ inhibitors are targeted at the ATP-binding site, which is highly conserved among diverse protein kinases, the development of novel non-ATP competitive $GSK3{\beta}$ inhibitors is needed. Methods: Based on the unique phosphorylation motif of $GSK3{\beta}$, we designed and generated a novel class of $GSK3{\beta}$ inhibitor (GSK3i) peptides. In addition, we investigated the effects of a GSK3i peptide on lipopolysaccharide (LPS)-stimulated cytokine production and septic shock. Mice were intraperitoneally injected with GSK3i peptide and monitored over a 7-day period for survival. Results: We first demonstrate its effects on LPS-stimulated pro-inflammatory cytokine production including interleukin (IL)-6 and IL-12p40. LPS-induced IL-6 and IL-12p40 production in macrophages was suppressed when macrophages were treated with the GSKi peptide. Administration of the GSK3i peptide potently suppressed LPS-mediated endotoxin shock. Conclusion: Collectively, we present a rational strategy for the development of a therapeutic GSK3i peptide. This peptide may serve as a novel template for the design of non-ATP competitive GSK3 inhibitors.

• 통합자연과학논문집
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• 제13권4호
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• pp.170-180
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• 2020

Abnormal regulation, hyperphosphorylation, and aggregation of the tau protein are the hallmark of several types of dementia, including Alzheimer's Disease. Increased activity of Glycogen Synthase Kinase-3β (GSK-3β) in the Central Nervous System (CNS), increased the tau hyperphosphorylation and caused the neurofibrillary tangles (NFTs) formation in the brain cells. Over the last two decades, numerous adenosine triphosphate (ATP) competitive inhibitors have been discovered that show inhibitory activity against GSK-3β. But these compounds exhibited off-target effects which motivated researchers to find new GSK-3β inhibitors. In the present study, we have collected the dataset of 31 C-Glycosylflavones derivatives that showed inhibitory activity against GSK-3β. Among the dataset, the most active compound was docked with the GSK-3β and molecular dynamics (MD) simulation was performed for 50 ns. Based on the 50 ns MD pose of the most active compound, the other dataset compounds were sketched, minimized, and aligned. The 3D-QSAR based Comparative Molecular Field Analysis (CoMFA) model was developed, which showed a reasonable value of q2=0.664 and r2=0.920. The contour maps generated based on the CoMFA model elaborated on the favorable substitutions at the R2 position. This study could assist in the future development of new GSK-3β inhibitors.

• 통합자연과학논문집
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• 제8권1호
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• pp.40-47
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• 2015

Glycogen synthase kinase 3 (GSK-3) is a serine/threonine protein kinase that has recently emerged as a promising target in drug discovery. It is involved in multiple cellular processes and associated with the pathogenesis of several diseases. A three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis was performed on a series of GSK-3 inhibitors to understand the structural basis for inhibitory activity. Comparative molecular field analysis (CoMFA) method was used to derive 3D-QSAR models. A reliable CoMFA model was developed using ligand-based alignment scheme. The model produced statistically acceptable results with a cross-validated correlation coefficient ($q^2$) of 0.594 and a non-cross-validated correlation coefficient ($r^2$) of 0.943. Robustness of the model was checked by bootstrapping and progressive scrambling analysis. This study could assist in the design of novel compounds with enhanced GSK-3 inhibitory activity.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.2015-2020
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• 2011

A series of isoxazol-indolin-2-one was designed for GSK-3${\beta}$ inhibitors as novel anticancer agents based on their binding mode analysis in GSK-3${\beta}$ crystal structure. Total 21 compounds were synthesized and evaluated for their inhibitory activity against two tumor cell lines (DU145 and HT29). Most of the synthesized compounds were potent with above 80% inhibitory activity at 100 ${\mu}M$, and several compounds were examined for inhibitory activity against GSK-3${\beta}$. Among them, 15(Z) ($R_1$=H, $R_2$=3-Cl-phenyl) was most active with 78% inhibition of tumor cell line (HT29) at 20 ${\mu}M$ and 72% inhibition of GSK-3${\beta}$ at 20 ${\mu}M$.

• 통합자연과학논문집
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• 제12권4호
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• pp.133-141
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• 2019

Mesenchymal stem cells (MSCs) are known to differentiate into multiple lineages, making neurogenic differentiation an important target in the clinical field. In the present study, we induced the neurogenic differentiation of cells using histone deacetylase (HDAC) inhibitors and studied their mechanisms for further differentiation in vitro. We treated cells with the HDAC inhibitors, MS-275 and NaB; and found that the cells had neuron-like features such as distinct bipolar or multipolar morphologies with branched processes. The mRNA expressions encoding for NEFL, MAP2, TUJ1, OLIG2, and SYT was significantly increased following HDAC inhibitors treatment compared to without HDAC inhibitors; high protein levels of MAP2 and Tuj1 were detected by immunofluorescence staining. We examined the mechanisms of differentiation and found that the Wnt signaling pathway and downstream mitogen-activate protein kinase were involved in neurogenic differentiation of MSCs. Importantly, Wnt4, Wnt5a/b, and Wnt11 protein levels were highly increased after treatment with NaB; signals were activated through the regulation of Dvl2 and Dvl3. Interestingly, NaB treatment increased the levels of JNK and upregulated JNK phosphorylation. After MS-275 treatment, Wnt protein levels were decreased and GSK-3β was phosphorylated. In this cell, HDAC inhibitors controlled the non-canonical Wnt expression by activating JNK phosphorylation and the canonical Wnt signaling by targeting GSK-3β.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.1170-1176
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• 2015

Ginsenosides, the major active component of ginseng, are traditionally used to treat various diseases, including cancer, inflammation, and obesity. Among these, compound K (CK), an intestinal bacterial metabolite of the ginsenosides Rb₁, Rb₂, and Rc from Bacteroides JY-6, is reported to inhibit cancer cell growth by inducing cell-cycle arrest or cell death, including apoptosis and necrosis. However, the precise effect of CK on breast cancer cells remains unclear. MCF-7 cells were treated with CK ($0-70{\mu}M$) for 24 or 48 h. Cell proliferation and death were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. Changes in downstream signaling molecules involved in cell death, including glycogen synthase kinase $3\beta$ ($GSK3\beta$), $GSK3\beta$, $\beta$-catenin, and cyclin D1, were analyzed by western blot assay. To block $GSK3\beta$ signaling, MCF-7 cells were pretreated with $GSK3\beta$ inhibitors 1 h prior to CK treatment. Cell death and the expression of $\beta$-catenin and cyclin D1 were then examined. CK dose- and time-dependently inhibited MCF-7 cell proliferation. Interestingly, CK induced programmed necrosis, but not apoptosis, via the $GSK3\beta$ signaling pathway in MCF-7 cells. CK inhibited $GSK3\beta$ phosphorylation, thereby suppressing the expression of $\beta$-catenin and cyclin D1. Our results suggest that CK induces programmed necrosis in MCF-7 breast cancer cells via the $GSK3\beta$ signaling pathway.

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.127-138
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• 2023

Glycogen synthase kinase-3β (GSK-3β) is an important serine/threonine kinase that implicates in multiple cellular processes and links with the neurodegenerative diseases including Alzheimer's disease (AD). In this study, structure-based virtual screening was performed to search database for compounds targeting GSK-3β from Enamine's screening collection. Of the top-ranked compounds, 7 primary hits underwent a luminescent kinase assay and a cell assay using human neuroblastoma SH-SY5Y cells expressing Tau repeat domain (Tau_RD) with pro-aggregant mutation ΔK280. In the kinase assay for these 7 compounds, residual GSK-3β activities ranged from 36.1% to 90.0% were detected at the IC₅₀ of SB-216763. In the cell assay, only compounds VB-030 and VB-037 reduced Tau aggregation in SH-SY5Y cells expressing ΔK280 Tau_RD-DsRed folding reporter. In SH-SY5Y cells expressing ΔK280 Tau_RD, neither VB-030 nor VB-037 increased expression of GSK-3α Ser21 or GSK-3β Ser9. Among extracellular signal-regulated kinase (ERK), AKT serine/threonine kinase 1 (AKT), mitogen-activated protein kinase 14 (P38) and mitogenactivated protein kinase 8 (JNK) which modulate Tau phosphorylation, VB-037 attenuated active phosphorylation of P38 Thr180/ Tyr182, whereas VB-030 had no effect on the phosphorylation status of ERK, AKT, P38 or JNK. However, both VB-030 and VB-037 reduced endogenous Tau phosphorylation at Ser202, Thr231, Ser396 and Ser404 in neuronally differentiated SH-SY5Y expressing ΔK280 Tau_RD. In addition, VB-030 and VB-037 further improved neuronal survival and/or neurite length and branch in mouse hippocampal primary culture under Tau cytotoxicity. Overall, through inhibiting GSK-3β kinase activity and/or p-P38 (Thr180/Tyr182), both compounds may serve as promising candidates to reduce Tau aggregation/cytotoxicity for AD treatment.

• 대한화장품학회지
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• 제37권3호
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• pp.211-218
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• 2011

Glycogen synthase kinase 3 beta (GSK3${\beta}$)의 선택적 저해제인 Kenpaullone가 B16 멜라노마 및 사람의 멜라노사이트에 미치는 멜라닌 합성능을 조사하였다. Kepaullone은 B16 멜라노마 및 사람의 멜라노사이트에 대하여 세포증식에는 영향이 없는 범위 내에서 농도 의존적으로 멜라닌 합성을 촉진시켰다. B16 멜라노마 세포에 Kenpaullone을 첨가 48 h 후 tyrosinase 활성이 증가하였으며, 농도별 처리에 대하여 tyrosinase 단백질의 발현 및 tyrosinase mRNA양이 증가함을 관찰하였다. 결론적으로 Kenpaullone는 B16 멜라노마 세포에서 tyrosinase 효소의 발현을 증가시켜 멜라닌 합성을 촉진하는 것으로 판단되어진다. 따라서 GSK3${\beta}$ 저해제가 멜라닌 합성을 촉진시키는 결과는 백반증과 같은 저색소관련 질병의 치료제 개발의 가능성을 갖고 있는 소재로서 응용가능하리라고 판단되어진다.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1513-1520
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• 2010

A bacterium capable of producing melanin pigment in the presence of L-tyrosine was isolated from a crop field soil sample and identified as Klebsiella sp. GSK based on morphological, biochemical, and 16S rDNA sequencing. The polymerization of this pigment occurs outside the cell wall, which has a granular structure as melanin ghosts. Chemical characterization of the pigment particles showed then to be acid resistant, alkali soluble, and insoluble in most of the organic solvents and water. The pigment got bleached when subjected to the action of oxidants as well as reductants. This pigment was precipitated with $FeCl_3$, ammoniacal silver nitrate, and potassium ferricynide. The pigment showed high absorbance in the UV region and decreased absorbance when shifted towards the visible region. The melanin pigment was further charecterized by FT-IR and EPR spectroscopies. A key enzyme, 4-hydroxyphenylacetic acid hydroxylase, that catalyzes the formation of melanin pigment by hydroxylation of L-tyrosine was detected in this bacterium. Inhibition studies with specific inhibitors, kojic acid and KCN, proved that melanin is synthesized by the DOPA-melanin pathway.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1384-1391
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• 2006

The signal transduction system is one of the most important devices involved in maintaining life, and many protein kinases are included in the cellular signal transduction system. Finding a protein kinase inhibitor is very valuable, as it can be used to study cell biology and applied to pharmaceuticals. For the efficient and rapid screening of protein kinase inhibitors, two assay systems were combined; the nonradioactive protein kinase assay system that uses an FITC-labeled IRS-2 peptide and the cell-based paper disc assay system that uses Streptomyces griseus as the indicator strain. Among 330 kinds of herb extracts tested, the extract of Dalbergia odorifera exhibited the strongest inhibitory activity in the two assay systems and was selected for further isolation. Based on solvent extraction and many steps of chromatography, seven compounds were finally separated to homogeneity and their structures determined by $^{1}H$ and $^{13}C$ NMR spectroscopies. Four were to be flavonoids and identified as butin ($C_{15}H_{12}O_5$, Mw=272.07), 3'-hydroxymelanetin ($C_{16}H_{12}O_6$, Mw=300.06), liquiritigenin ($C_{15}H_{12}O_4$, Mw=256.07), and 2'-hydroxyformononetin ($C_{16}H_{12}O_{5}$, Mw=284.07). 3'-Hydroxymelanetin inhibited the phosphorylation of the GSK3 protein by Akt to 37% at a concentration of $10{\mu}g/ml$ and showed the strongest cytotoxicity ($ED_{50}<50{\mu}g/ml$) against the human cancer cell line HCT116. Under the same conditions, liquiritigenin also inhibited the phosphorylation of GSK3 by Akt to 26%, and its cytotoxicity against the HCT116 cell line was lower than $100{\mu}g/ml$.