Publications by authors named "Gi-Young Kim"

384 Publications

Nargenicin A1 attenuates lipopolysaccharide-induced inflammatory and oxidative response by blocking the NF-κB signaling pathway.

EXCLI J 2021 28;20:968-982. Epub 2021 May 28.

Anti-Aging Research Center, Dong-eui University, Busan, Republic of Korea.

Inflammation caused by the excessive production of pro-inflammatory mediators and cytokines in abnormally activated macrophages promotes the initiation and progression of many diseases along with oxidative stress. Previous studies have suggested that nargenicin A1, an antibacterial macrolide isolated from sp. may be a potential treatment for inflammatory responses and oxidative stress, but the detailed mechanisms are still not well studied. In this study, we investigated the inhibitory effect of nargenicin A1 on inflammatory and oxidative stress in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and zebrafish () models. Our results indicated that nargenicin A1 treatment significantly inhibited LPS-induced release of pro-inflammatory mediators including nitric oxide (NO) and prostaglandin E, which was associated with decreased inducible NO synthase and cyclooxygenase-2 expression. In addition, nargenicin A1 attenuated the LPS-induced expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and monocyte chemotactic protein-1, reducing their extracellular secretion. Nargenicin A1 also suppressed LPS-induced generation of reactive oxygen species. Moreover, nargenicin A1 abolished the LPS-mediated nuclear translocation of nuclear factor-kappa B (NF-κB) and the degradation of inhibitor IκB-α, indicating that nargenicin A1 exhibited anti-inflammatory effects by inhibiting the NF-κB signaling pathway. Furthermore, nargenicin A1 showed strong protective effects against NO and ROS production in LPS-injected zebrafish larvae. In conclusion, our findings suggest that nargenicin A1 ameliorates LPS-induced anti-inflammatory and antioxidant effects by downregulating the NF-κB signaling pathway, and that nargenicin A1 can be a potential functional agent to prevent inflammatory- and oxidative-mediated damage.
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http://dx.doi.org/10.17179/excli2021-3506DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8278209PMC
May 2021

Fisetin promotes osteoblast differentiation and osteogenesis through GSK-3β phosphorylation at Ser9 and consequent β-catenin activation, inhibiting osteoporosis.

Biochem Pharmacol 2021 Jul 10;192:114676. Epub 2021 Jul 10.

Department of Marine Life Science, Jeju National University, Jeju 63243, Republic of Korea; Research Institute for Basic Sciences, Jeju National University, Jeju 63243, Republic of Korea. Electronic address:

Fisetin is a bioactive flavonol that inhibits osteoclastogenesis and promotes osteoblastogenesis. However, the osteogenic activity of fisetin needs to be comprehensively elucidated. In the present study, we observed that fisetin significantly increased alkaline phosphatase (ALP) activity and bone mineralization in MC3T3-E1 preosteoblasts, accompanied by a significant increase in runt-related transcription factor 2 (RUNX2), ALP, collagen type Ⅰ alpha 1 (Col1α1), osterix (OSX), osteocalcin (OCN), and bone morphogenetic protein 4 (BMP4) expression. Furthermore, fisetin promoted vertebral formation in zebrafish larvae, with the highest fisetin concentration comparable with that observed in β-glycerophosphate treatment. Fisetin also inhibited prednisolone (PDS)-induced anti-osteoblastic genes, including nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), tartrate-resistant acid phosphatase-6 (ACP6), dendritic cell-specific transmembrane protein (DC-STAMP), and cathepsin K (CTSK). Fisetin potently mitigated the PDS-induced inhibition of ALP activity and bone mineralization, as well as vertebral resorption in zebrafish larvae. Moreover, we confirmed that fisetin-induced osteogenic effect was activated through phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser9, consequently releasing β-catenin from the destructive complex to promote its nuclear translocation. β-Catenin inhibition by FH535 and the stabilization of GSK-3β by DOI hydrochloride remarkably inhibited fisetin-induced osteogenic activities, indicating that the GSK-3β/β-catenin signaling pathway plays a vital role in fisetin-induced osteogenesis. Collectively, our findings suggest that fisetin stimulates osteogenic activity and could be used as an effective strategy to prevent bone resorption.
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http://dx.doi.org/10.1016/j.bcp.2021.114676DOI Listing
July 2021

The anti-cancer effect of betulinic acid in u937 human leukemia cells is mediated through ROS-dependent cell cycle arrest and apoptosis.

Anim Cells Syst (Seoul) 2021 23;25(2):119-127. Epub 2021 Apr 23.

Anti-Aging Research Center, Dong-eui University, Busan, Republic of Korea.

Although previous studies have shown anti-cancer activity of betulinic acid (BA), a pentacyclic triterpenoid, against various cancer lines, the underlying molecular mechanisms are not well elucidated. In this study, we evaluated the mechanisms involved in the anti-cancer efficacy of BA in U937 human myeloid leukemia cells. BA exerted a significant cytotoxic effect on U937 cells through blocking cell cycle arrest at the G2/M phase and inducing apoptosis, and that the intracellular reactive oxygen species (ROS) levels increased after treatment with BA. The down-regulation of cyclin A and cyclin B1, and up-regulation of cyclin-dependent kinase inhibitor p21WAF1/CIP1 revealed the G2/M phase arrest mechanism of BA. In addition, BA induced the cytosolic release of cytochrome by reducing the mitochondrial membrane potential with an increasing Bax/Bcl-2 expression ratio. BA also increased the activity of caspase-9 and -3, and subsequent degradation of the poly (ADP-ribose) polymerase. However, quenching of ROS by -acetyl-cysteine, an ROS scavenger, markedly abolished BA-induced G2/M arrest and apoptosis, indicating that the generation of ROS plays a key role in inhibiting the proliferation of U937 cells by BA treatment. Taken together, our results provide a mechanistic rationale that BA exhibits anti-cancer properties in U937 leukemia cells through ROS-dependent induction of cell cycle arrest at G2/M phase and apoptosis.
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http://dx.doi.org/10.1080/19768354.2021.1915380DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8118407PMC
April 2021

Inhibition of Lipopolysaccharide-Induced Inflammatory and Oxidative Responses by -cinnamaldehyde in C2C12 Myoblasts.

Int J Med Sci 2021 23;18(12):2480-2492. Epub 2021 Apr 23.

Anti-Aging Research Center, Dong-eui University, Busan 47340, Republic of Korea.

-cinnamaldehyde (tCA), a bioactive component found in , has been reported to exhibit anti-inflammatory and antioxidant effects, but its efficacy in muscle cells has yet to be found. In this study, we investigated the inhibitory effect of tCA on inflammatory and oxidative stress induced by lipopolysaccharide (LPS) in C2C12 mouse skeletal myoblasts. To investigate the anti-inflammatory and antioxidant effects of tCA in LPS-treated C2C12 cells, we measured the levels of pro-inflammatory mediator, cytokines, and reactive oxygen species (ROS). To elucidate the mechanism underlying the effect of tCA, the expression of genes involved in the expression of inflammatory and oxidative regulators was also investigated. We further evaluated the anti-inflammatory and antioxidant efficacy of tCA against LPS in the zebrafish model. tCA significantly inhibited the LPS-induced release of pro-inflammatory mediators and cytokines, which was associated with decreased expression of their regulatory genes. tCA also suppressed the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor, and attenuated the nuclear translocation of nuclear factor-kappa B (NF-κB) and the binding of LPS to TLR4 on the cell surface in LPS-treated C2C12 cells. Furthermore, tCA abolished LPS-induced generation of ROS and expression levels of ROS producing enzymes, NADPH oxidase 1 (NOX1) and NOX2. However, tCA enhanced the activation of nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and the expression of heme oxygenase-1 (HO-1) in LPS-stimulated C2C12 myoblasts. In addition, tCA showed strong protective effects against NO and ROS production in LPS-injected zebrafish larvae. Our findings suggest that tCA exerts its inhibitory ability against LPS-induced inflammatory and antioxidant stress in C2C12 myoblasts by targeting the TLR4/NF-κB, which might be mediated by the NOXs and Nrf2/HO-1 pathways.
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http://dx.doi.org/10.7150/ijms.59169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8176176PMC
April 2021

Loganin Inhibits Lipopolysaccharide-Induced Inflammation and Oxidative Response through the Activation of the Nrf2/HO-1 Signaling Pathway in RAW264.7 Macrophages.

Biol Pharm Bull 2021 ;44(6):875-883

Anti-Aging Research Center, Dong-eui University.

Inflammation caused by the excessive secretion of inflammatory mediators in abnormally activated macrophages promotes many diseases along with oxidative stress. Loganin, a major iridoid glycoside isolated from Cornus officinalis, has recently been reported to exhibit anti-inflammatory and antioxidant effects, whereas the underlying mechanism has not yet been fully clarified. Therefore, the aim of the present study is to investigate the effect of loganin on inflammation and oxidative stress in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Our results indicated that loganin treatment markedly attenuated the LPS-mediated phagocytic activity and release of nitric oxide (NO) and prostaglandin E, which was associated with decreased the expression of inducible NO synthase and cyclooxygenase-2. In addition, loganin suppressed the expression and their extracellular secretion of LPS-induced pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-1β. Furthermore, loganin abolished reactive oxygen species (ROS) generation, and promoted the activation of nuclear factor-E2-related factor 2 (Nrf2) and the expression of heme oxygenase-1 (HO-1) in LPS-stimulated macrophages. However, zinc protoporphyrin, a selective HO-1 inhibitor, reversed the loganin-mediated suppression of pro-inflammatory cytokines in LPS-treated macrophages. In conclusion, our findings suggest that the upregulation of the Nrf2/HO-1 signaling pathway is concerned at least in the protective effect of loganin against LPS-mediated inflammatory and oxidative stress, and that loganin can be a potential functional agent to prevent inflammatory and oxidative damage.
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http://dx.doi.org/10.1248/bpb.b21-00176DOI Listing
January 2021

Anti-Inflammatory Effect of Auranofin on Palmitic Acid and LPS-Induced Inflammatory Response by Modulating TLR4 and NOX4-Mediated NF-κB Signaling Pathway in RAW264.7 Macrophages.

Int J Mol Sci 2021 May 31;22(11). Epub 2021 May 31.

Department of Biochemistry, Dong-eui University College of Korean Medicine, Busan 47227, Korea.

Chronic inflammation, which is promoted by the production and secretion of inflammatory mediators and cytokines in activated macrophages, is responsible for the development of many diseases. Auranofin is a Food and Drug Administration-approved gold-based compound for the treatment of rheumatoid arthritis, and evidence suggests that auranofin could be a potential therapeutic agent for inflammation. In this study, to demonstrate the inhibitory effect of auranofin on chronic inflammation, a saturated fatty acid, palmitic acid (PA), and a low concentration of lipopolysaccharide (LPS) were used to activate RAW264.7 macrophages. The results show that PA amplified LPS signals to produce nitric oxide (NO) and various cytokines. However, auranofin significantly inhibited the levels of NO, monocyte chemoattractant protein-1, and pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, which had been increased by co-treatment with PA and LPS. Moreover, the expression of inducible NO synthase, IL-1β, and IL-6 mRNA and protein levels increased by PA and LPS were reduced by auranofin. In particular, the upregulation of NADPH oxidase (NOX) 4 and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induced by PA and LPS were suppressed by auranofin. The binding between the toll-like receptor (TLR) 4 and auranofin was also predicted, and the release of NO and cytokines was reduced more by simultaneous treatment with auranofin and TLR4 inhibitor than by auranofin alone. In conclusion, all these findings suggested that auranofin had anti-inflammatory effects in PA and LPS-induced macrophages by interacting with TLR4 and downregulating the NOX4-mediated NF-κB signaling pathway.
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http://dx.doi.org/10.3390/ijms22115920DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198732PMC
May 2021

The regulation of the TLR4/NF-κB and Nrf2/HO-1 signaling pathways is involved in the inhibition of lipopolysaccharide-induced inflammation and oxidative reactions by morroniside in RAW 264.7 macrophages.

Arch Biochem Biophys 2021 Jul 23;706:108926. Epub 2021 May 23.

Anti-Aging Research Center, Dong-eui University, Busan, 47340, Republic of Korea; Department of Biochemistry, Dong-eui University College of Korean Medicine, Busan, 47227, Republic of Korea. Electronic address:

Morroniside, a major iridoid glycoside isolated from Cornus officinalis, has a variety of beneficial pharmacological properties. Although morroniside has recently been reported to exhibit anti-inflammatory and antioxidant effects, the detailed mechanism has not yet been fully elucidated. In this study, we investigated the inhibitory effect of morroniside on inflammatory and oxidative stress activated by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Our results indicated that morroniside pretreatment significantly inhibited the LPS-induced phagocytic activity and release of pro-inflammatory factors, which was associated with blocking the expression of their regulatory genes. Morroniside also markedly suppressed the expression of myeloid differentiation factor 88 as well as Toll-like receptor 4 (TLR4), and attenuated the translocation of nuclear factor-κB (NF-κB) to the nucleus in LPS-treated RAW 264.7 macrophages. Furthermore, morroniside prevented the binding of LPS to the TLR4 on the cell surface. In addition, morroniside abolished reactive oxygen species (ROS) generation, and enhanced the expression of heme oxygenase-1 (HO-1) following activation of nuclear factor-E2-related factor 2 (Nrf2) in LPS-stimulated RAW 264.7 macrophages. However, zinc protoporphyrin, a specific inhibitor of HO-1, reversed the morroniside-mediated inhibition of inflammatory response in LPS-treated RAW 264.7 macrophages. In conclusion, our findings suggest that morroniside exerts LPS-induced anti-inflammatory and antioxidant effects by targeting the TLR4/NF-κB and Nrf2/HO-1 signaling pathways in RAW 264.7 macrophages. Taken together, our findings suggest that morroniside interacted structurally and electrochemically with TLR4/MD2 complex, consequently can be a potential functional agent to prevent inflammatory and oxidative damage.
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http://dx.doi.org/10.1016/j.abb.2021.108926DOI Listing
July 2021

ROS-Mediated Anti-Tumor Effect of Coptidis Rhizoma against Human Hepatocellular Carcinoma Hep3B Cells and Xenografts.

Int J Mol Sci 2021 Apr 30;22(9). Epub 2021 Apr 30.

Anti-Aging Research Center, Dongeui University, Busan 47340, Korea.

Coptidis Rhizoma is the dried rhizome from the Franch. that has been shown to have a number of beneficial pharmacological properties including antioxidant, anti-inflammatory, and anti-cancer effects. However, the anti-cancer effects of Coptidis Rhizoma on hepatocellular carcinoma (HCC) remain unclear. In this study, we investigated the anti-cancer properties of Coptidis Rhizoma ethanol extract (CR) in HCC Hep3B cells and in a xenograft mouse model. Our results showed that the CR significantly inhibited cell growth and induced apoptosis in Hep3B cells through increased expression of Bcl-2 associated x-protein (Bax) and cleavage of poly-ADP ribose polymerase (PARP), reduced expression of Bcl-2, and activated caspases. CR also increased the generation of intracellular reactive oxygen species (ROS), which caused a loss of mitochondrial membrane potential (MMP, ΔΨm) and activation of the mitochondria-mediated intrinsic apoptosis pathway. Moreover, -acetylcysteine (NAC), a ROS inhibitor, markedly blocked the effects of CR on apoptotic pathways. CR also induced the expression of light chain 3 (LC3)-I/II, a key autophagy regulator, whereas CR-mediated autophagy was significantly suppressed by NAC. In addition, pre-treatment with NAC perfectly attenuated the inhibition of cell invasion and migration of CR-stimulated Hep3B cells. Furthermore, oral administration of CR suppressed Hep3B tumor growth in xenograft mice without toxicity, alterations to body weight, or changes in hematological and biochemical profiles. Taken together, our findings suggest that CR has anti-tumor effects that result from ROS generation, and may be a potential pharmacological intervention for HCC.
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http://dx.doi.org/10.3390/ijms22094797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8124566PMC
April 2021

LCT-3d Induces Oxidative Stress-Mediated Apoptosis by Upregulating Death Receptor 5 in Gastric Cancer Cells.

Front Oncol 2021 16;11:658608. Epub 2021 Apr 16.

Key Laboratory of Advanced Technology for Drug Preparation, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China.

Gastric cancer is a global health problem. In this study, we investigate the role of a novel Indole derivative, named LCT-3d, in inhibiting the growth of gastric cancer cells by MTT assay. The Western blotting results showed that LCT-3d modulated the mitochondrial-related proteins and Cleaved-Caspases 3/9, to induce cell apoptosis. The up-regulation of Death receptor 5 (DR5) in MGC803 cells was observed with LCT-3d treatment. Knockdown of DR5 on MGC803 cells partially reversed the LCT-3d-induced mitochondrial apoptosis. The level of Reactive Oxygen Species (ROS) in MGC803 cells was increased with LCT-3d treatment and could be blocked with the pretreatment of the ROS inhibitor N-Acetylcysteine (NAC). The results demonstrate that the elevating ROS can up-regulate the expression of DR5, resulting in apoptosis mitochondrial pathway. Although the nuclear factor erythroid-2 related factor 2 (Nrf2) pathway served an important role in protecting gastric cancer cells against the injury of ROS, it can't reverse LCT-3d-induced cell apoptosis. Taken together, our study showed that LCT-3d induced apoptosis DR5-mediated mitochondrial apoptotic pathway in gastric cancer cells. LCT-3d could be a novel lead compound for development of anti-cancer activity in gastric cancer.
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http://dx.doi.org/10.3389/fonc.2021.658608DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8085419PMC
April 2021

Influence of Material Properties on the Damage-Reporting and Self-Healing Performance of a Mechanically Active Dynamic Network Polymer in Coating Applications.

Molecules 2021 Apr 23;26(9). Epub 2021 Apr 23.

Center for Advanced Specialty Chemicals, Division of Specialty and Bio-based Chemicals Technology, Korea Research Institute of Chemical Technology (KRICT), Ulsan 44412, Korea.

We conducted a detailed investigation of the influence of the material properties of dynamic polymer network coatings on their self-healing and damage-reporting performance. A series of reversible polyacrylate urethane networks containing the damage-reporting diarylbibenzofuranone unit were synthesized, and their material properties (e.g., indentation modulus, hardness modulus, and glass-transition temperature) were measured conducting nanoindentation and differential scanning calorimetry experiments. The damage-reporting and self-healing performances of the dynamic polymer network coatings exhibited opposite tendencies with respect to the material properties of the polymer network coatings. Soft polymer network coatings with low glass-transition temperature (~10 °C) and indentation hardness (20 MPa) exhibited better self-healing performance (almost 100%) but two times worse damage-reporting properties than hard polymer network coatings with high glass-transition temperature (35~50 °C) and indentation hardness (150~200 MPa). These features of the dynamic polymer network coatings are unique; they are not observed in elastomers, films, and hydrogels, whereby the polymer networks are bound to the substrate surface. Evidence indicates that controlling the polymer's physical properties is a key factor in designing high-performance self-healing and damage-reporting polymer coatings based on mechanophores.
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http://dx.doi.org/10.3390/molecules26092468DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122913PMC
April 2021

Protective Effect of Anthocyanin-Enriched Polyphenols from L. (Malvaceae) against Ultraviolet B-Induced Damage.

Antioxidants (Basel) 2021 Apr 9;10(4). Epub 2021 Apr 9.

Department of Marine Life Science, Jeju National University, Jeju 63243, Korea.

Anthocyanin-enriched polyphenols from the flower petals of L. (Malvaceae, AHs) possess anti-septic shock, anti-oxidant, and anti-melanogenic properties. However, whether AHs positively or negatively regulate ultraviolet B (UVB)-mediated photoaging and photodamage remains unclear. This study aims to investigate the protective effect of AHs against UVB-induced damage. We examined the photoprotective effects of AHs on UVB-induced apoptosis, endoplasmic reticulum (ER) stress, and mitochondrial reactive oxygen species (mtROS). AHs prevented UVB irradiation-induced apoptosis of HaCaT keratinocytes by inhibiting caspase activation and ROS production. Moreover, AHs restored the survival rate and the hatchability of UVB-irradiated zebrafish larvae without any abnormalities. Furthermore, AHs inhibited UVB-induced ER stress, resulting in a decrease in mtROS production via the stabilization of the mitochondrial membrane potential. Our results indicate that AHs inhibit UVB-induced apoptosis by downregulating total cytosolic ROof cytosolic CaS and ER-mediated mitoROS production in both HaCaT keratinocytes and zebrafish larvae. These findings provide evidence for the applications of AHs to protect skin from UVB-induced photodamage.
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http://dx.doi.org/10.3390/antiox10040584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069133PMC
April 2021

Fisetin inhibits lipopolysaccharide-induced inflammatory response by activating β-catenin, leading to a decrease in endotoxic shock.

Sci Rep 2021 Apr 16;11(1):8377. Epub 2021 Apr 16.

Department of Marine Life Science, Jeju National University, Jeju, 63243, Republic of Korea.

Fisetin is a naturally occurring flavonoid that possesses several pharmacological benefits including anti-inflammatory activity. However, its precise anti-inflammatory mechanism is not clear. In the present study, we found that fisetin significantly inhibited the expression of proinflammatory mediators, such as nitric oxide (NO) and prostaglandin E (PGE), and cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Additionally, fisetin attenuated LPS-induced mortality and abnormalities in zebrafish larvae and normalized the heart rate. Fisetin decreased the recruitment of macrophages and neutrophils to the LPS-microinjected inflammatory site in zebrafish larvae, concomitant with a significant downregulation of proinflammatory genes, such as inducible NO synthase (iNOS), cyclooxygenase-2a (COX-2a), IL-6, and TNF-α. Fisetin inhibited the nuclear localization of nuclear factor-kappa B (NF-κB), which reduced the expression of pro-inflammatory genes. Further, fisetin inactivated glycogen synthase kinase 3β (GSK-3β) via phosphorylation at Ser9, and inhibited the degradation of β-catenin, which consequently promoted the localization of β-catenin into the nucleus. The pharmacological inhibition of β-catenin with FH535 reversed the fisetin-induced anti-inflammatory activity and restored NF-κB activity, which indicated that fisetin-mediated activation of β-catenin results in the inhibition of LPS-induced NF-κB activity. In LPS-microinjected zebrafish larvae, FH535 promoted the migration of macrophages to the yolk sac and decreased resident neutrophil counts in the posterior blood island and induced high expression of iNOS and COX-2a, which was accompanied by the inhibition of fisetin-induced anti-inflammatory activity. Altogether, the current study confirmed that the dietary flavonoid, fisetin, inhibited LPS-induced inflammation and endotoxic shock through crosstalk between GSK-3β/β-catenin and the NF-κB signaling pathways.
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http://dx.doi.org/10.1038/s41598-021-87257-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8052411PMC
April 2021

Suppression of Lipopolysaccharide-Induced Inflammatory and Oxidative Response by 5-Aminolevulinic Acid in RAW 264.7 Macrophages and Zebrafish Larvae.

Biomol Ther (Seoul) 2021 Apr 6. Epub 2021 Apr 6.

Anti-Aging Research Center, Dong-eui University, Busan 47340, Republic of Korea.

In this study, we investigated the inhibitory effect of 5-aminolevulinic acid (ALA), a heme precursor, on inflammatory and oxidative stress activated by lipopolysaccharide (LPS) in RAW 264.7 macrophages by estimating nitric oxide (NO), prostaglandin E2 (PGE2), cytokines, and reactive oxygen species (ROS). We also evaluated the molecular mechanisms through analysis of the expression of their regulatory genes, and further evaluated the anti-inflammatory and antioxidant efficacy of ALA against LPS in the zebrafish model. Our results indicated that ALA treatment significantly attenuated the LPS-induced release of pro-inflammatory mediators including NO and PGE2, which was associated with decreased inducible NO synthase and cyclooxygenase-2 expression. ALA also inhibited the LPS-induced expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, reducing their extracellular secretion. Additionally, ALA abolished ROS generation, improved the mitochondrial mass, and enhanced the expression of heme oxygenase-1 (HO-1) and the activation of nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) in LPS-stimulated RAW 264.7 macrophages. However, zinc protoporphyrin, a specific inhibitor of HO-1, reversed the ALA-mediated inhibition of pro-inflammatory cytokines production and activation of mitochondrial function in LPS-treated RAW 264.7 macrophages. Furthermore, ALA significantly abolished the expression of LPS-induced pro-inflammatory mediators and cytokines, and showed strong protective effects against NO and ROS production in zebrafish larvae. In conclusion, our findings suggest that ALA exerts LPS-induced anti-inflammatory and antioxidant effects by upregulating the Nrf2/HO-1 signaling pathway, and that ALA can be a potential functional agent to prevent inflammatory and oxidative damage.
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http://dx.doi.org/10.4062/biomolther.2021.030DOI Listing
April 2021

Betulinic Acid Restricts Human Bladder Cancer Cell Proliferation In Vitro by Inducing Caspase-Dependent Cell Death and Cell Cycle Arrest, and Decreasing Metastatic Potential.

Molecules 2021 Mar 4;26(5). Epub 2021 Mar 4.

Anti-Aging Research Center, Dong-eui University, Busan 47340, Korea.

Betulinic acid (BA) is a naturally occurring pentacyclic triterpenoid and generally found in the bark of birch trees ( sp.). Although several studies have been reported that BA has diverse biological activities, including anti-tumor effects, the underlying anti-cancer mechanism in bladder cancer cells is still lacking. Therefore, this study aims to investigate the anti-proliferative effect of BA in human bladder cancer cell lines T-24, UMUC-3, and 5637, and identify the underlying mechanism. Our results showed that BA induced cell death in bladder cancer cells and that are accompanied by apoptosis, necrosis, and cell cycle arrest. Furthermore, BA decreased the expression of cell cycle regulators, such as cyclin B1, cyclin A, cyclin-dependent kinase (Cdk) 2, cell division cycle (Cdc) 2, and Cdc25c. In addition, BA-induced apoptosis was associated with mitochondrial dysfunction that is caused by loss of mitochondrial membrane potential, which led to the activation of mitochondrial-mediated intrinsic pathway. BA up-regulated the expression of Bcl-2-accociated X protein (Bax) and cleaved poly-ADP ribose polymerase (PARP), and subsequently activated caspase-3, -8, and -9. However, pre-treatment of pan-caspase inhibitor markedly suppressed BA-induced apoptosis. Meanwhile, BA did not affect the levels of intracellular reactive oxygen species (ROS), indicating BA-mediated apoptosis was ROS-independent. Furthermore, we found that BA suppressed the wound healing and invasion ability, and decreased the expression of Snail and Slug in T24 and 5637 cells, and matrix metalloproteinase (MMP)-9 in UMUC-3 cells. Taken together, this is the first study showing that BA suppresses the proliferation of human bladder cancer cells, which is due to induction of apoptosis, necrosis, and cell cycle arrest, and decrease of migration and invasion. Furthermore, BA-induced apoptosis is regulated by caspase-dependent and ROS-independent pathways, and these results provide the underlying anti-proliferative molecular mechanism of BA in human bladder cancer cells.
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http://dx.doi.org/10.3390/molecules26051381DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961550PMC
March 2021

Bisphenol A: A potential Toll-like receptor 4/myeloid differentiation factor 2 complex agonist.

Environ Pollut 2021 Jun 1;278:116829. Epub 2021 Mar 1.

Department of Marine Life Science, Jeju National University, Jeju, 63243, Republic of Korea. Electronic address:

In addition to endocrine disruption, bisphenol A (BPA) is known to induce inflammation through the activation of nuclear factor-κB (NF-κB). However, detailed studies on the mechanism of NF-κB activation by BPA have not been sufficiently conducted. In the present study, we observed that low concentrations of BPA (≤1 μM) upregulated the release of proinflammatory mediators, including nitric oxide (NO) and prostaglandin E (PGE), as well as proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-12, and IL-6. Molecular modeling predicted that BPA docked with the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) complex activates downstream molecules including myeloid differentiation primary response 88 (MyD88) and IL-1 receptor-associated kinase 4 (IRAK-4) and results in the upregulation of the NF-κB signaling pathway. Additionally, BPA increased morphological abnormalities and mortality in zebrafish larvae and enhanced the dispersal of macrophages and neutrophils in the whole body, thereby causing an endotoxemia-like disorder. However, a specific TLR4 inhibitor, TLR4-IN-C34, mitigated BPA-induced mortality and morphological abnormalities, which indicates that the TLR4/MD2 complex is a molecular target of BPA-induced immunotoxicity. Collectively, our results indicate that low concentrations of BPA, which is a potential agonist of the TLR4/MD2 complex, can intensify the immune response and eventually cause an endotoxemia-like disorder.
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http://dx.doi.org/10.1016/j.envpol.2021.116829DOI Listing
June 2021

Anthocyanins from L. Inhibit NLRP3 Inflammasome in BV2 Microglia Cells by Alleviating NF-B- and ER Stress-Induced Ca Accumulation and Mitochondrial ROS Production.

Oxid Med Cell Longev 2021 4;2021:1246491. Epub 2021 Feb 4.

Department of Marine Life Science, Jeju National University, Jeju 63243, Republic of Korea.

Anthocyanins from the petals of L. (PS) possess anti-inflammatory, antioxidant, and antimelanogenic activities. However, it remains unclear whether PS inhibit the NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation and assembly. This study is aimed at investigating whether PS downregulate NLRP3-mediated inflammasome by inhibiting nuclear factor-B (NF-B) and endoplasmic reticulum (ER) stress. BV2 microglia cells were treated with PS in the presence of lipopolysaccharide and adenosine triphosphate (LPS/ATP), and the NLRP3-related signaling pathway was investigated. In this study, we found that LPS/ATP treatment activated the NLRP3 inflammasome, which resulted in the release of interleukin-1 (IL-1) and IL-18. Meanwhile, PS reduced LPS/ATP-mediated NLRP3 inflammasome at 12 h by inhibiting ER stress-mediated Ca accumulation and subsequent mitochondrial reactive oxygen species (mtROS) production, which, in turn, decreased IL-1 and IL-18 release. Furthermore, PS inhibited the NLRP3 inflammasome 1 h after LPS/ATP treatment by suppressing the NF-B pathway, which downregulated Ca accumulation and mtROS production. These data showed that PS negatively regulated activation of the NLRP3 inflammasome in a time-different manner by inhibiting the NF-B signaling pathway in the early stage and the ER stress response in the late stage. The pathways shared Ca accumulation-mediated mtROS production, which was significantly inhibited in the presence of PS. In conclusion, our results suggested that PS has potential as a supplement against NLRP3 inflammasome-related inflammatory disorders; nevertheless, further studies are needed to determine the effect of PS in the noncanonical NLRP3 inflammasome pathways and pathological conditions in vivo.
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http://dx.doi.org/10.1155/2021/1246491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7878077PMC
May 2021

Spermidine Attenuates Oxidative Stress-Induced Apoptosis via Blocking Ca Overload in Retinal Pigment Epithelial Cells Independently of ROS.

Int J Mol Sci 2021 Jan 29;22(3). Epub 2021 Jan 29.

Anti-Aging Research Center, Dong-eui University, Busan 47340, Korea.

Retinal pigment epithelial (RPE) cells occupy the outer layer of the retina and perform various biological functions. Oxidative damage to RPE cells is a major risk factor for retinal degeneration that ultimately leads to vision loss. In this study, we investigated the role of spermidine in a hydrogen peroxide (HO)-induced oxidative stress model using human RPE cells. Our findings showed that 300 μM HO increased cytotoxicity, apoptosis, and cell cycle arrest in the G2/M phase, whereas these effects were markedly suppressed by 10 μM spermidine. Furthermore, spermidine significantly reduced HO-induced mitochondrial dysfunction including mitochondrial membrane potential and mitochondrial activity. Although spermidine displays antioxidant properties, the generation of intracellular reactive oxygen species (ROS) upon HO insult was not regulated by spermidine. Spermidine did suppress the increase in cytosolic Ca levels resulting from endoplasmic reticulum stress in HO-stimulated human RPE cells. Treatment with a cytosolic Ca chelator markedly reversed HO-induced cellular dysfunction. Overall, spermidine protected against HO-induced cellular damage by blocking the increase of intracellular Ca independently of ROS. These results suggest that spermidine protects RPE cells from oxidative stress, which could be a useful treatment for retinal diseases.
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http://dx.doi.org/10.3390/ijms22031361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7866386PMC
January 2021

Urban Aerosol Particulate Matter Promotes Necrosis and Autophagy via Reactive Oxygen Species-Mediated Cellular Disorders that are Accompanied by Cell Cycle Arrest in Retinal Pigment Epithelial Cells.

Antioxidants (Basel) 2021 Jan 20;10(2). Epub 2021 Jan 20.

Anti-Aging Research Center, Dong-eui University, Busan 47340, Korea.

Urban particulate matter (UPM) is recognized as a grave public health problem worldwide. Although a few studies have linked UPM to ocular surface diseases, few studies have reported on retinal dysfunction. Thus, the aim of the present study was to evaluate the influence of UPM on the retina and identify the main mechanism of UPM toxicity. In this study, we found that UPM significantly induced cytotoxicity with morphological changes in ARPE-19 human retinal pigment epithelial (RPE) cells and increased necrosis and autophagy but not apoptosis. Furthermore, UPM significantly increased G2/M arrest and simultaneously induced alterations in cell cycle regulators. In addition, DNA damage and mitochondrial dysfunction were remarkably enhanced by UPM. However, the pretreatment with the potent reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) effectively suppressed UPM-mediated cytotoxicity, necrosis, autophagy, and cell cycle arrest. Moreover, NAC markedly restored UPM-induced DNA damage and mitochondrial dysfunction. Meanwhile, UPM increased the expression of mitophagy-regulated proteins, but NAC had no effect on mitophagy. Taken together, although further studies are needed to identify the role of mitophagy in UPM-induced RPE injury, the present study provides the first evidence that ROS-mediated cellular damage through necrosis and autophagy is one of the mechanisms of UPM-induced retinal disorders.
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http://dx.doi.org/10.3390/antiox10020149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7909535PMC
January 2021

Indirubin-3'-monoxime induces paraptosis in MDA-MB-231 breast cancer cells by transmitting Ca from endoplasmic reticulum to mitochondria.

Arch Biochem Biophys 2021 02 13;698:108723. Epub 2020 Dec 13.

Department of Marine Life Science, Jeju National University, Jeju, 63243, Republic of Korea. Electronic address:

Purpose: Indirubin-3'-monoxime (I3M) induces cell death in many cancer cells; however, whether I3M regulates paraptosis is unclear. The present study aimed to investigate I3M-induced paraptosis.

Methods: We treated various cancer cells with I3M, and measured vacuole formation (a paraptosis marker) and the regulating signaling pathway such as endoplasmic reticulum (ER) stress, reactive oxygen species, and proteasomal dysfunction.

Results: We found that I3M induced small vacuole formation in MDA-MB-231 breast cancer cells and transient knockdown of eIF2α and CHOP significantly downregulated vacuolation in the ER and mitochondria, as well as cell death in response to I3M, indicating that I3M-meditaed paraptosis was upregulated by ER stress. Moreover, I3M accumulated ubiquitinylated proteins via proteasome dysfunction, which stimulated ER stress-mediated Ca release. A Ca chelator significantly downregulated vacuolation in the ER and mitochondria as well as cell death, suggesting that Ca was a key regulator in I3M-induced paraptosis. Our results also revealed that Ca finally transited in mitochondria through mitochondrial Ca uniporter (MCU), causing I3M-mediated paraptosis; however, the paraptosis was completely inhibited by, ruthenium red, an MCU inhibitor.

Conclusion: I3M induced proteasomal dysfunction-mediated ER stress and subsequently promoted Ca release, which was accumulated in the mitochondria via MCU, thus causing paraptosis in MDA-MB-231 breast cancer cells.
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http://dx.doi.org/10.1016/j.abb.2020.108723DOI Listing
February 2021

Inhibition of oxidative stress induced-cytotoxicity by coptisine in V79-4 Chinese hamster lung fibroblasts through the induction of Nrf-2 mediated HO-1 expression.

Genes Genomics 2021 Jan 25;43(1):17-31. Epub 2020 Nov 25.

Department of Biochemistry, Dong-eui University College of Korean Medicine, 47227, Busan, Republic of Korea.

Background: Coptisine is a natural alkaloid compound and is known to have multiple beneficial effects including antioxidant activity. However, whether it can protect lung fibroblasts from oxidative damage has not been studied yet.

Objectives: To investigate the potential inhibitory effect of coptisine against oxidative stress in V79-4 lung fibroblast cells.

Methods: V79-4 cells were treated with HO (1 mM) in the presence or absence of coptisine (50 µg/ml), N-acetyl cysteine (NAC, 10 mM) or zinc protoporphyrin IX (ZnPP, 10 µM) for the indicated times. The alleviating effects of coptisine on cytotoxicity, cell cycle arrest, apoptosis, reactive oxygen species (ROS) production, DNA damage, mitochondrial dynamics, and inhibition of ATP production against HO were investigated. Western blot analysis was used to analyze the expression levels of specific proteins.

Results: Coptisine inhibited HO-induced cytotoxicity and DNA damage by blocking abnormal ROS generation. HO treatment caused cell cycle arrest at the G2/M phase accompanied by increased expression of cyclin-dependent kinase (Cdk) inhibitor p21 and decreased expression of cyclin B1 and cyclin A. However, these effects were attenuated in the presence of coptisine or NAC. Coptisine also prevented apoptosis by decreasing the rate of Bax/Bcl-2 expression in HO-stimulated cells and suppressing the loss of mitochondrial membrane potential and the cytosolic release of cytochrome c. In addition, the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was markedly promoted by coptisine in the presence of HO. However, zinc protoporphyrin IX, a potent inhibitor of HO-1, attenuated the ROS scavenging and anti-apoptotic effects of coptisine.

Conclusions: Based on current data, we suggest that coptisine can be used as a potential treatment for oxidative stress-related lung disease.
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http://dx.doi.org/10.1007/s13258-020-01018-3DOI Listing
January 2021

Coptisine induces autophagic cell death through down-regulation of PI3K/Akt/mTOR signaling pathway and up-regulation of ROS-mediated mitochondrial dysfunction in hepatocellular carcinoma Hep3B cells.

Arch Biochem Biophys 2021 01 21;697:108688. Epub 2020 Nov 21.

Department of Biochemistry, Dong-eui University College of Korean Medicine and Anti-Aging Research Center, Dong-eui University, Busan, 47227, Republic of Korea. Electronic address:

Coptisine is isoquinoline alkaloid derived from Coptidis Rhizoma and is known to have potential anti-cancer activity toward various carcinomas. Targeting autophagy is one of the main approaches for cancer therapy, but whether the anti-cancer efficacy of coptisine involves autophagy is still unclear. Therefore, this study investigated the effect of coptisine on autophagy in hepatocellular carcinoma (HCC) Hep3B cells, and identified the underlying mechanism. Our results showed that coptisine increased cytotoxicity and autophagic vacuoles in a concentration-dependent manner. Furthermore, the expressions of light chain 3 (LC3)-I/II, Beclin-1 and autophagy genes were markedly increased by coptisine, while the expression of p62 decreased. In addition, we found that pretreatment with bafilomycin A1, an inhibitor of autophagosome-lysosome fusion, markedly reduced coptisine-mediated autophagic cell death, but 3-methyladenine, an inhibitor for autophagosome formation did not. Moreover, our results showed that although coptisine up-regulated AMP-activated protein kinase (AMPK) that partially induced LC3-I/II, coptisine-mediated AMPK signaling did not directly regulate autophagic cell death. Additionally, we found that coptisine suppressed the phosphorylation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), and this effect was notably enhanced by PI3K inhibitor LY294002. Meanwhile, coptisine significantly increased both the production of mitochondrial reactive oxygen species (ROS) and the recruitment of mitophagy-regulated proteins to mitochondria. Furthermore, N-acetylcysteine, a potential ROS scavenger, substantially suppressed the expression of mitophagy-regulated proteins and LC3 puncta by coptisine. Overall, our results demonstrate that coptisine-mediated autophagic cell death was regulated by PI3K/Akt/mTOR signaling and mitochondrial ROS production associated with mitochondrial dysfunction. Taken together, these findings suggest that coptisine exerts its anti-cancer effects through induction of autophagy in HCC Hep3B cells.
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http://dx.doi.org/10.1016/j.abb.2020.108688DOI Listing
January 2021

Protective Effects of against Hydrogen Peroxide-Induced Oxidative Stress and Cell Death in Skin Keratinocytes.

Life (Basel) 2020 Oct 27;10(11). Epub 2020 Oct 27.

Nakdonggang National Institute of Biological Resources, 137, Donam 2-gil, Sangju-si, Gyeongsangbuk-do 37242, Korea.

Background: (evening primrose) produces bioactive substances with a diverse range of pharmacological functions. However, it is currently unknown whether extract prepared from the aerial parts of (APOB) can protect the skin against oxidative stress.

Objective: The aim of this study is to investigate the protective effects of APOB against oxidative stress-induced damage in human skin keratinocytes (HaCaT) and elucidate the underlying mechanisms.

Methods: We pretreated HaCaT cells with various concentrations of APOB or the antioxidant N-acetyl-L-cysteine before applying HO. We then compared the cell viability, intracellular reactive oxygen species (ROS) production, and DNA and mitochondrial damage between pretreated and untreated control cells using a range of assays, flow cytometry, and Western blot analysis and also examined the reducing power and DPPH free radical scavenging activity of APOB.

Results: APOB pretreatment significantly increased cell viability, effectively attenuated HO-induced comet tail formation, and inhibited HO-induced phosphorylation of the histone γH2AX, as well as the number of apoptotic bodies and Annexin V-positive cells. APOB was found to have high reducing power and DPPH radical scavenging activity and also exhibited scavenging activity against intracellular ROS accumulation and restored the loss of mitochondrial membrane potential caused by HO. APOB pretreatment almost totally reversed the enhanced cleavage of caspase-3, the degradation of poly (ADP-ribose)-polymerase (PARP), DNA fragmentation that usually occurs in the presence of HO, and increased the levels of heme oxygenase-1 (HO-1), a potent antioxidant enzyme that is associated with the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2).

Conclusions: APOB can protect HaCaT cells from HO-induced DNA damage and cell death by blocking cellular damage related to oxidative stress via a mechanism that affects ROS elimination and by activating the Nrf2/HO-1 signaling pathway.
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http://dx.doi.org/10.3390/life10110255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693688PMC
October 2020

Auranofin Attenuates Non-Alcoholic Fatty Liver Disease by Suppressing Lipid Accumulation and NLRP3 Inflammasome-Mediated Hepatic Inflammation In Vivo and In Vitro.

Antioxidants (Basel) 2020 Oct 23;9(11). Epub 2020 Oct 23.

Department of Biochemistry, College of Korean Medicine, Dong-eui University, Busan 47227, Korea.

Non-alcoholic fatty liver disease (NAFLD) causes liver dysfunction and is associated with obesity and type 2 diabetes. Chronic inflammation is associated not only with the development of NAFLD, but also with hepatic diseases, including steatohepatitis, cirrhosis, and hepatocellular carcinoma. Auranofin is a treatment for rheumatoid arthritis and has recently been reported to have potential effects against a variety of diseases, including inflammation, cancer, and viral infection. In this study, auranofin may be considered as a new treatment for the management of metabolic syndrome, as well as in the treatment of NAFLD through immunomodulation. To determine the effect of auranofin on NAFLD, C57BL/6 mice were randomly grouped, fed a regular diet or a high fat diet (HFD), and injected with normal saline or auranofin for 8 weeks. Auranofin significantly decreased the body weight, epididymal fat weight, serum aspartate aminotransferase (AST), and glucose, as well as the serum triglyceride, cholesterol, and low-density lipoprotein cholesterol levels as compared to the HFD group. We also observed that hepatic steatosis was increased in the HFD group and was suppressed by auranofin treatment. In addition, auranofin suppressed the expressions of interleukin (IL)-1β, IL-18, caspase-1, and the NOD-like receptor family pyrin domain containing 3 (NLRP3) in the liver tissue. Furthermore, the expression of NADPH oxidase 4 and peroxisome proliferator-activated receptor γ (PPARγ), which are a major source of oxidative stress and a regulator of adipogenesis, respectively, were also decreased by auranofin. In addition, primary mouse hepatocytes were incubated with lipopolysaccharide (LPS) and palmitic acid (PA) to induce lipid accumulation and hepatic inflammation for an in vitro model. Auranofin could significantly inhibit LPS- and PA-induced inflammatory activity including nitric oxide and NLRP3 inflammasome-mediated cytokines. The results of this study demonstrate that auranofin treatment inhibits the characteristics of NAFLD through the inhibition of NLRP3 inflammasome. Therefore, auranofin may have potential as a candidate for improving NAFLD symptoms.
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http://dx.doi.org/10.3390/antiox9111040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7690872PMC
October 2020

The immunostimulatory effect of indole-6-carboxaldehyde isolated from in RAW 264.7 macrophages.

Anim Cells Syst (Seoul) 2020 Aug 20;24(4):233-241. Epub 2020 Aug 20.

Anti-Aging Research Center, Dong-eui University, Busan, Republic of Korea.

Indole-6-carboxaldehyde (I6CA), an indole derivative isolated from the marine brown algae , is known to have several beneficial effects, but no studies on immune regulation have been conducted. In this study, the immunomodulatory properties of I6CA on murine RAW 264.7 monocyte/macrophage cells were evaluated. As the concentration of I6CA increased, the morphology of RAW 264.7 cells changed to a typical active macrophage shape, and the phagocytic activity increased significantly. I6CA effectively enhanced the production and secretion of immunomodulatory mediators and cytokines due to increased expression of their respective genes. Additionally, I6CA markedly stimulated the expression of Toll-like receptor 4 (TLR4) and its adapter molecule, myeloid differentiation factor 88 (Myd88), and increased TLR4 complexed with Myd88. Furthermore, I6CA promoted the nuclear translocation of nuclear factor-kappa B (NF-κB) by increasing the degradation of the inhibitor of NF-κB-. Meanwhile, similar trends were also found in lipopolysaccharide-treated cells as a positive control. Furthermore, molecular docking simulation showed that I6CA interacted with TLR4-myeloid differentiation 2 complex. Taken together, the results support the concept that I6CA may increase the activity of the TLR4/NF-κB signaling pathway in order to enhance the immunomodulatory activity of RAW 264.7 cells.
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http://dx.doi.org/10.1080/19768354.2020.1808529DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7473310PMC
August 2020

Cytoprotective effects of fermented oyster extracts against oxidative stress-induced DNA damage and apoptosis through activation of the Nrf2/HO-1 signaling pathway in MC3T3-E1 osteoblasts.

EXCLI J 2020 4;19:1102-1119. Epub 2020 Aug 4.

Anti-Aging Research Center, Dong-eui University, Busan, Republic of Korea.

Osteoblast damage by oxidative stress has been recognized as a cause of bone-related disease, including osteoporosis. Recently, we reported that fermented Pacific oyster () extracts (FO) inhibited osteoclastogenesis and osteoporosis, while promoting osteogenesis. However, since the beneficial potential of FO on osteoblasts is not well known, in the present study, we investigated the cytoprotective effect of FO against oxidative stress in MC3T3-E1 osteoblasts. Our results demonstrated that FO inhibited hydrogen peroxide (HO)-induced DNA damage and cytotoxicity through the rescue of mitochondrial function by blocking abnormal ROS accumulation. FO also prevented apoptosis by suppressing loss of mitochondrial membrane potential and cytosolic release of cytochrome , decreasing the rate of Bax/Bcl-2 expression and reducing the activity of caspase-9 and caspase-3 in HO-stimulated MC3T3-E1 osteoblasts, suggesting that FO protected MC3T3-E1 osteoblasts from the induction of caspase dependent- and mitochondria-mediated apoptosis by oxidative stress. In addition, FO markedly promoted the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2), which was associated with the enhanced expression of heme oxygenase-1 (HO-1). However, inhibiting the expression of HO-1 by artificially blocking the expression of Nrf2 using siRNA significantly eliminated the protective effect of FO, indicating that FO activates the Nrf2/HO-1 signaling pathway in MC3T3-E1 osteoblasts to protect against oxidative stress. Based on the present data, FO is thought to be useful as a potential therapeutic agent for the inhibition of oxidative stress in osteoblasts.
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http://dx.doi.org/10.17179/excli2020-2376DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527492PMC
August 2020

Gamma Aminobutyric Acid-Enriched Fermented Oyster () Increases the Length of the Growth Plate on the Proximal Tibia Bone in Sprague-Dawley Rats.

Molecules 2020 Sep 23;25(19). Epub 2020 Sep 23.

Anti-Aging Research Center, Dong-eui University, Busan 47340, Korea.

Bone growth during childhood and puberty determines an adult's final stature. Although several prior studies have reported that fermented oyster (FO) consisting of a high amount of gamma aminobutyric acid can be attributed to bone health, there is no research on the efficacy of FO on growth regulation and the proximal tibial growth plate. Therefore, in this study, we investigated the effect of FO oral administration on hepatic and serum growth regulator levels and the development of the proximal tibial growth plate in young Sprague-Dawley rats. Both oral administration of FO (FO 100, 100 mg/kg FO and FO 200, 200 mg/kg FO) and subcutaneous injection of recombinant human growth hormone (rhGH, 200 μg/kg of rhGH) for two weeks showed no toxicity. Circulating levels of growth hormone (GH) significantly increased in the FO 200 group. The expression and secretion of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) were enhanced by FO administration. FO administration promoted the expression of bone morphogenic proteins IGF-1 and IGFBP-3 in the proximal tibial growth plate. This positive effect of FO resulted in incremental growth of the entire plate length by expanding the proliferating and hypertrophic zones in the proximal tibial growth plate. Collectively, our results suggested that oral administration of FO is beneficial for bone health, which may ultimately result in increased height.
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http://dx.doi.org/10.3390/molecules25194375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7582314PMC
September 2020

Fermented Oyster Extract Promotes Insulin-Like Growth Factor-1-Mediated Osteogenesis and Growth Rate.

Mar Drugs 2020 Sep 18;18(9). Epub 2020 Sep 18.

Department of Marine Life Science, Jeju National University, Jeju 63243, Korea.

Fermented oyster () extract (FO) prevents ovariectomy-induced osteoporosis by inhibiting osteoclastogenesis and activating osteogenesis. However, the molecular mechanisms underlying FO-mediated bone formation and growth rate are unclear. In the current study, we found that FO significantly upregulated the expression of growth-promoting genes in zebrafish larvae including insulin-like growth factor 1 (), insulin-like growth factor binding protein 3 (), growth hormone-1 (), growth hormone receptor-1 (), growth hormone receptor alpha (), glucokinase (), and cholecystokinin (). In addition, zebrafish larvae treated with 100 μg/mL FO increased in total body length (3.89 ± 0.13 mm) at 12 days post fertilization (dpf) compared to untreated larvae (3.69 ± 0.02 mm); this effect was comparable to that of the β-glycerophosphate-treated zebrafish larvae (4.00 ± 0.02 mm). Furthermore, FO time- and dose-dependently increased the extracellular release of IGF-1 from preosteoblast MC3T3-E1 cells, which was accompanied by high expression of . Pharmacological inhibition of IGF-1 receptor (IGF-1R) using picropodophyllin (PPP) significantly reduced FO-mediated vertebrae formation (from 9.19 ± 0.31 to 5.53 ± 0.35) and growth performance (from 3.91 ± 0.02 to 3.69 ± 0.01 mm) in zebrafish larvae at 9 dpf. Similarly, PPP significantly decreased FO-induced calcium deposition in MC3T3-E1 cells by inhibiting GSK-3β phosphorylation at Ser9. Additionally, DOI hydrochloride, a potent stabilizer of GSK-3β, reduced FO-induced nuclear translocation of RUNX2. Transient knockdown of / using specific silencing RNA also resulted in a significant decrease in calcium deposition and reduction in GSK-3β phosphorylation at Ser9 in MC3T3-E1 cells. Altogether, these results indicate that FO increased phosphorylated GSK-3β at Ser9 by activating the autocrine IGF-1-mediated IGF-1R signaling pathway, thereby promoting osteogenesis and growth performance. Therefore, FO is a potential nutritional supplement for bone formation and growth.
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http://dx.doi.org/10.3390/md18090472DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551862PMC
September 2020

Auranofin Enhances Sulforaphane-Mediated Apoptosis in Hepatocellular Carcinoma Hep3B Cells through Inactivation of the PI3K/Akt Signaling Pathway.

Biomol Ther (Seoul) 2020 Sep;28(5):443-455

Anti-Aging Research Center, Dong-eui University, Busan 47340, Republic of Korea.

The thioredoxin (Trx) system plays critical roles in regulating intracellular redox levels and defending organisms against oxidative stress. Recent studies indicated that Trx reductase (TrxR) was overexpressed in various types of human cancer cells indicating that the Trx-TrxR system may be a potential target for anti-cancer drug development. This study investigated the synergistic effect of auranofin, a TrxR-specific inhibitor, on sulforaphane-mediated apoptotic cell death using Hep3B cells. The results showed that sulforaphane significantly enhanced auranofin-induced apoptosis by inhibiting TrxR activity and cell proliferation compared to either single treatment. The synergistic effect of sulforaphane and auranofin on apoptosis was evidenced by an increased annexin-V-positive cells and Sub-G1 cells. The induction of apoptosis by the combined treatment caused the loss of mitochondrial membrane potential (ΔΨm) and upregulation of Bax. In addition, the proteolytic activities of caspases (-3, -8, and -9) and the degradation of poly (ADP-ribose) polymerase, a substrate protein of activated caspase-3, were also higher in the combined treatment. Moreover, combined treatment induced excessive generation of reactive oxygen species (ROS). However, treatment with N-acetyl-L-cysteine, a ROS scavenger, reduced combined treatment-induced ROS production and apoptosis. Thereby, these results deduce that ROS played a pivotal role in apoptosis induced by auranofin and sulforaphane. Furthermore, apoptosis induced by auranofin and sulforaphane was significantly increased through inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Taken together, the present study demonstrated that down-regulation of TrxR activity contributed to the synergistic effect of auranofin and sulforaphane on apoptosis through ROS production and inhibition of PI3K/Akt signaling pathway.
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http://dx.doi.org/10.4062/biomolther.2020.122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7457169PMC
September 2020

Induction of Apoptosis by Coptisine in Hep3B Hepatocellular Carcinoma Cells through Activation of the ROS-Mediated JNK Signaling Pathway.

Int J Mol Sci 2020 Jul 31;21(15). Epub 2020 Jul 31.

Anti-Aging Research Center, Dong-Eui University, Busan 47340, Korea.

Hepatocellular carcinoma (HCC) has a high mortality rate worldwide, and treatment is very limited due to its high recurrence and low diagnosis rate, and therefore there is an increasing need to develop more effective drugs to treat HCC. Coptisine is one of the isoquinoline alkaloids, and it has various pharmacological effects. However, the evidence for the molecular mechanism of the anticancer efficacy is still insufficient. Therefore, this study investigated the antiproliferative effect of coptisine on human HCC Hep3B cells and identified the action mechanism. Our results showed that coptisine markedly increased DNA damage and apoptotic cell death, which was associated with induction of death receptor proteins. Coptisine also significantly upregulated expression of proapoptotic Bax protein, downregulated expression of anti-apoptotic Bcl-2 protein, and activated caspase-3, -8, and -9. In addition, coptisine remarkably increased the generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP), and release of cytochrome into the cytoplasm. However, -acetylcysteine (NAC), a ROS scavenger, significantly attenuated the apoptosis-inducing effect of coptisine. It is worth noting that coptisine significantly upregulated phosphorylation of ROS-dependent c-Jun N-terminal kinase (JNK), whereas treatment with JNK inhibitor could suppress an apoptosis-related series event. Taken together, our results suggest that coptisine has an anticancer effect in Hep3B cells through ROS-mediated activation of the JNK signaling pathway.
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http://dx.doi.org/10.3390/ijms21155502DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7432186PMC
July 2020

Inhibitory effect of oolonghomobisflavan B on osteoclastogenesis by suppressing p38 MAPK activation.

Bioorg Med Chem Lett 2020 09 21;30(18):127429. Epub 2020 Jul 21.

Department of Oral Pathology and Regenerative Medicine, School of Dentistry, IHBR, Kyungpook National University, Daegu 41940, Republic of Korea. Electronic address:

Suppression of differentiation and/or function of osteoclasts is considered an effective therapeutic strategy for osteolytic bone diseases such as periodontitis and osteoporosis. Evidence regarding the health benefits of oolong tea consumption is accumulating, and tea polyphenols have various pharmacological properties such as anti-cancer and anti-diabetes effects. In this study, we investigated the effect of oolonghomobisflavan B (OFB), a polyphenolic compound in oolong tea, on osteoclast differentiation. OFB suppressed receptor activator of nuclear factor-κB (RANKL)-induced formation of tartate-resistant acid phosphatase-positive multinuclear cells without cytotoxicity. OFB also significantly attenuated p38 phosphorylation, which is essential for RANKL-induced osteoclastogenesis, and inhibited the expressions of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) and osteoclast-specific target genes, including dendritic cell-specific transmembrane protein and cathepsin K. Our findings suggest that OFB exhibits an anti-osteoclastogenic activity by inhibiting RANKL-mediated p38 activation, which is useful for the prevention and treatment of osteolytic bone diseases.
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http://dx.doi.org/10.1016/j.bmcl.2020.127429DOI Listing
September 2020