• 생약학회지
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• 제39권3호
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• pp.213-217
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• 2008

Oxidative stress is considered to play an important role in a variety of neurodegenerative disorders of central nervous system. The immortalized mouse hippocampal cell line, HT22, phenotypically resembles neuronal precursor cells but lacks functional ionotropic glutamate receptors, thus excluding excitotoxicity as a cause for glutamate triggered cell death. Therefore, HT22 cells are a useful model for studying oxidative glutamate toxicity. In this study, we examined whether the methanol extracts of some native plants at Mt. Baekdu could protect HT22-immortalized hippocampal cells against glutamate-induced oxidative stress. Seventy-eight plants sources were collected at Mt. Baekdu, and extracted with methanol. These extracts had been screened the protective effects against glutamate-induced oxidative damage in HT22 cells at the 100 and 300 ${\mu}g/ml$. Of these, thirteen methanolic extracts, Acer mono (leaf), Artemisia stolonifera (aerial part), Carduus crispus (aerial part), Carex mongolica (whole plant), Clematis hexapetala (whole plant), Galeopsis bifida (aerial part), Galium verum (whole plant), Ganoderma lucidum (whole plant), Ixeris chinensis (whole plant), Malva verticillata (aerial part), Polygonum senticosum (whole plant), Rebes mandshricum (branch), and Taraxacum mongolicum (aerial part), showed significant protective effects against glutamate-induced oxidative damage in HT22 cells.

• 대한한의학회지
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• 제32권1호
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• pp.109-120
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• 2011

Objectives: The aim of this investigation was to evaluate the efficacy of KHchunggan-tang aqueous extract on the experimental nonalcoholic fatty liver disease(NAFLD) induced by palmitate. Materials and Methods: To generate a cellular model of NAFLD, we used HepG2 cells, a human hepatoma cell line, treated with 0.5 mM palmitate. By this cellular model, effects of KHchunggan-tang aqueous extract were evaluated. Intracellular lipid accumulation, free radical formation, and apoptosis were detected by Nile red staining, 2',7'-dichloroflourescin diacetate(H2DCF-DA), and 4',6-diamidino-2-phenylindole(DAPI)/propidium iodide(PI) staining, respectively. Some proteins related with NAFLD were determined by western blot. Results: Typical pathological features of NAFLD occurred in the cellular model. Palmitate increased the levels of intracellular lipid vacuoles, decreased cell viability, and increased apoptosis. Palmitate increased free radical formation and lipid peroxidation, too. However, KHchunggan-tang aqueous extract reduced palmitate-induced pathologic features, i.e. steatosis, free radical formation, and apoptosis. In addition, KHchunggan-tang aqueous extract suppressed palmitate-activated c-Jun N-terminal kinase(JNK) signaling, and SP600125, a JNK inhibitor, significantly reversed the palmitate-induced pathologic changes as KHchunggan-tang aqueous extract. It means that the signaling pathway other than JNK can be involved in the KHchunggan-tang mediated cellular protection of palmitate-treated Hep G2 cells. Conclusions: These results suggest that KHchunggan-tang aqueous extract has hepatoprotective effects on NAFLD with combined properties in cellular steatosis, ROS production, and cytoprotection, and thus may have valuable clinical applications for treatment of this chronic liver disease.

• Molecules and Cells
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• 제38권5호
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• pp.416-425
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• 2015

NF-E2-related factor 2 (Nrf2), a basic leucine zipper transcription factor, has recently received a great deal of attention as an important molecule that enhances antioxidative defenses and induces resistance to chemotherapy or radiotherapy. In this study, we investigated the apoptosis-inducing and Nrf2- upregulating effects of quercetin on malignant mesothelioma (MM) MSTO-211H and H2452 cells. Quercetin treatment inhibited cell growth and led to upregulation of Nrf2 at both the mRNA and protein levels without altering the ubiquitination and extending the half-life of the Nrf2 protein. Following treatment with quercetin, analyses of the nuclear level of Nrf2, Nrf2 antioxidant response element-binding assay, Nrf2 promoter-luc assay, and RT-PCR toward the Nrf2-regulated gene, heme oxygenase-1, demonstrated that the induced Nrf2 is transcriptionally active. Knockdown of Nrf2 expression with siRNA enhanced cytotoxicity due to the induction of apoptosis, as evidenced by an increase in the level of proapoptotic Bax, a decrease in the level of antiapoptotic Bcl-2 with enhanced cleavage of caspase-3 and PARP proteins, the appearance of a sub-$G_0/G_1$ peak in the flow cytometric assay, and increased percentage of apoptotic propensities in the annexin V binding assay. Effective reversal of apoptosis was observed following pretreatment with the pan-caspase inhibitor Z-VAD. Moreover, Nrf2 knockdown exhibited increased sensitivity to the anticancer drug, cisplatin, presumably by potentiating the oxidative stress induced by cisplatin. Collectively, our data demonstrate the importance of Nrf2 in cytoprotection, survival, and drug resistance with implications for the potential significance of targeting Nrf2 as a promising strategy for overcoming resistance to chemotherapeutics in MM.

• 생약학회지
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• 제39권1호
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• pp.68-73
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• 2008

The present study represents the screening of the protective effects of herbal methanolic extracts from Baekdu mountain against tacrine-induced cytotoxicity in HepG2 cells. Tacrine is an acetylcholinesterase inhibitor, and used for the treatment of Alzheimer's disease. However, administration of tacrine for the treatment of Alzheimer's disease results in a reversible hepatotoxicity in 30-50% of patients, consequently limiting clinical use. Therefore, studies for natural products with protective effect on the tacrine-induced hepatotoxicity would be valuable as providing potential therapeutic use. 109 plant sources were collected in Baekdu mountain, and extracted with methanol. These extracts had been screened the protective effects against tacrine-induced cytotoxicity in HepG2 cells at the 100 and 300 ${\mu}g/ml$. Of these, ten methanolic extracts, roots of Ampelosis japonica, aerial parts of Berberis amurensis, aerial parts of Sedum aizoon, aerial parts of Lespedeza tomentosa, aerial parts of Lespedeza juncea, aerial parts of Hypenricum ascyron, stem barks of Syringa reticulata, fruits of Gleditsia japonica, aerial parts of Chamaenerion angustifolium, branches of Ginkgo biloba, showed significant protective effects against tacrine-induced cytotoxicity in HepG2 cells.

• Archives of Pharmacal Research
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• 제28권3호
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• pp.311-318
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• 2005

Oxidative stress has been reported to elevate ceramide level during cell death. The purpose of the present study was to modulate cell death in relation to cellular glutathione (GSH) level and GST (glutathione S-transferase) expression by regulating the sphingolipid metabolism. LLC­PK1 cells were treated with H$_2$O$_2$ in the absence of serum to induce cell death. Subsequent to exposure to H$_2$O$_2$, LLC-PK1 cells were treated with desipramine, sphingomyelinase inhibitor, and N-acetylcysteine (NAC), GSH substrate. Based on comparative visual observation with H202-treated control cells, it was observed that 0.5 $\mu$M of desipramine and 25 $\mu$M of NAC exhibited about 90 and $95\%$ of cytoprotection, respectively, against H$_2$O$_2$-induced cell death. Desipramine and NAC lowered the release of LDH activity by 36 and $3\%$ respectively, when compared to $71\%$ in H$_2$O$_2$-exposed cells. Cellular glutathione level in 500 $\mu$M H202-treated cells was reduced to 890 pmol as compared to control level of 1198 pmol per mg protein. GST P1-1 expression was decreased in H$_2$O$_2$-treated cells compared to healthy normal cells. In conclusion, it has been inferred that H$_2$O$_2$-induced cell death is closely related to cellular GSH level and GST P1-1 expression in LLC-PK1 cells and occurs via ceramide elevation by sphingomyelinase activation.

• 한방재활의학과학회지
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• 제20권2호
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• pp.51-61
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• 2010

Objectives : The purpose of this study was to investigate antioxidant effects of curcumin from Curcumae Longae Radix. Methods : Using HepG2 Iiver-like cells, the antioxidant effects of curcumin, one of main components from Curcumae Longae Radix, and its analogues have been evaluated by measuring their effects on cytotoxicity induced by $H_2O_2$. Results : The pre-incubation for 6 hours with curcumin, bis-demethoxycurcumin, or dimethoxycurcumin protected HepG2 cells from $H_2O_2$-induced toxicity in a dose-dependent manner. However, tetrahydrocurcumin, one of curcumin metabolites, did not protect HepG2 cells from $H_2O_2$-induced toxicity. Interestingly, curcumin, bis-demethoxycurcumin, and dimethoxycurcumin were increased in the protein levels of heme oxygenase-1(HO-1) at concentrations that were also effective in cellular protection. In contrast, tetrahydrocurcumin did not induce HO-1 expression. Tin protoporphyrin-IX, an inhibitor of HO-1 activity, significantly abolished cytoprotection afforded by curcumin, bis-demethoxycurcumin and dimethoxycurcumin. Conclusions : These results demonstrate that curcumin, bis-demethoxycurcumin, and dimethoxycurcumin with two conjugated doble bonds on their structures may reduce $H_2O_2$-induced oxidative stress through HO-1 expression. HO-1 induction may be one of antioxidant pathways by which curcumin protects from oxidative stress-induced cytotoxicity.

• 생약학회지
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• 제46권2호
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• pp.116-122
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• 2015

Keratinocytes are first barrier against outer challenges on skin. However, it is still largely unknown about effective protectors against ultraviolet B (UVB), and oxidative stress in human keratinocyte, HaCaT cells. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a role in the pathogenesis of skin disorders. Therefore, the purpose of this study was to evaluate the effect of Portulaca oleracea 70% EtOH extracts against hydrogen peroxide (H₂O₂)-induced oxidative stress in human keratinocytes, HaCaT cells. P. oleracea 70% EtOH extracts showed the potent protective effects on H₂O₂-induced toxicity by induced the expression of HO-1 in human keratinocyte, HaCaT cells. Furthermore, P. oleracea 70 % EtOH extracts caused the nuclear accumulation of nuclear factor E2-related factor 2 (Nrf2) in human keratinocytes, HaCaT cells. In addition, we found that treatment with c-Jun N-terminal kinase (JNK) inhibitor (SP600125) reduced P. oleracea 70% EtOH extracts-induced HO-1 expression, and JNK inhibitor (SP600125) also inhibited protective effects by P. oleracea 70% EtOH extracts. Therefore, these results suggest that P. oleracea 70 % EtOH extracts increases cellular resistance to H₂O₂-induced oxidative injury in human keratinocyte, HaCaT cells, presumably through JNK pathway-Nrf2-dependent HO-1 expression.

• Molecules and Cells
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• 제42권4호
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• pp.292-300
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• 2019

Immunometabolism, defined as the interaction of metabolic pathways with the immune system, influences the pathogenesis of metabolic diseases. Metformin and carbon monoxide (CO) are two pharmacological agents known to ameliorate metabolic disorders. There are notable similarities and differences in the reported effects of metformin and CO on immunometabolism. Metformin, an anti-diabetes drug, has positive effects on metabolism and can exert anti-inflammatory and anti-cancer effects via adenosine monophosphate-activated protein kinase (AMPK)-dependent and AMPK-independent mechanisms. CO, an endogenous product of heme oxygenase-1 (HO-1), can exert anti-inflammatory and antioxidant effects at low concentration. CO can confer cytoprotection in metabolic disorders and cancer via selective activation of the protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) pathway. Both metformin and CO can induce mitochondrial stress to produce a mild elevation of mitochondrial ROS (mtROS) by distinct mechanisms. Metformin inhibits complex I of the mitochondrial electron transport chain (ETC), while CO inhibits ETC complex IV. Both metformin and CO can differentially induce several protein factors, including fibroblast growth factor 21 (FGF21) and sestrin2 (SESN2), which maintain metabolic homeostasis; nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of the antioxidant response; and REDD1, which exhibits an anticancer effect. However, metformin and CO regulate these effects via different pathways. Metformin stimulates p53- and AMPK-dependent pathways whereas CO can selectively trigger the PERK-dependent signaling pathway. Although further studies are needed to identify the mechanistic differences between metformin and CO, pharmacological application of these agents may represent useful strategies to ameliorate metabolic diseases associated with altered immunometabolism.

• The Korean Journal of Physiology and Pharmacology
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• 제26권1호
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• pp.15-24
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• 2022

The development of selective targeting of drug molecules towards the mitochondria is an important issue related to therapy efficacy. In this study, we report that gallic acid (GA)-mitochondria targeting sequence (MTS)-H₃R₉ exhibits a dual role as a mitochondria-targeting vehicle with antioxidant activity for disease therapy. In viability assays, GA-MTS-H₃R₉ showed a better rescue action compared to that of MTS-H₃R₉. GA-MTS-H₃R₉ dramatically exhibited cell penetration and intercellular uptake compared to MTS and fit escape from lysosome release to the cytosol. We demonstrated the useful targeting of GA-MTS-H₃R₉ towards mitochondria in AC16 cells. Also, we observed that the antioxidant properties of mitochondrial-accrued GA-MTS-H₃R₉ alleviated cell damage by reactive oxygen species production and disrupted mitochondrial membrane potential. GA-MTS-H₃R₉ showed a very increased cytoprotective effect against anticancer activity compared to that of MTS-H₃R₉. We showed that GA-MTS-H₃R₉ can act as a vehicle for mitochondria-targeting and as a reagent for therapeutic applications intended for cardiovascular disease treatment.

• 대한본초학회지
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• 제39권1호
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• pp.23-29
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• 2024

Objectives : Polyporus umbellatus is a medicinal mushroom that has been used for over thousands years in Chinese medicine as a powerful diuretic to relieve fluid retention and edema. Dermal papilla is located at the bottom of the hair follicle and connected to the blood vessels where it gets the nutrients and oxygen to nurture hair follicle. This study examined the mechanism through which the ethanol extract of Polyporus umbellatus (EPU) promoted the proliferation of human dermal papilla cells (HHDPCs). Methods : To estimate the proliferative effects of EPU on HHDPCs, cell viability was estimated by thiazolyl blue tetrazolium bromide (MTT) assay. Western blotting was used to investgate the activation of ERK, phosphoinositide 3-kinase (PI3K)/Akt, β-catenin, GSK-3β and heme oxygenase-1 (HO-1). Cells were treated with inhibitors of ERK and Akt prior to EPU treatment. Results : EPU promoted the proliferation of HHDPCs and the phosphorylation of ERK and Akt in dose dependent manner. However, the proliferative effect of EPU on HHDPCs was inhibited by pre-treatment of ERK inhibitor (PD98059) and Akt inhibitor (LY294002). Furthermore, EPU respectively stimulated the protein expression of β-catenin and phosphorylated GSK-3β. EPU significantly increased the protein expression levels of proliferation and cytoprotection related genes such as Bcl-2, SIRT-1, and HO-1 in cells. Conclusion : This results suggest that EPU promoted the proliferation of HHDPCs via activating PI3K/Akt and Wnt/β-catenin signaling pathway in HHDPCs.