• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.90-97
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• 2021

Ultraviolet B (UVB) radiation causes DNA base modifications. One of these changes leads to the generation of 8-oxoguanine (8-oxoG) due to oxidative stress. In human skin, this modification may induce sunburn, inflammation, and aging and may ultimately result in cancer. We investigated whether phloroglucinol (1,3,5-trihydroxybenzene), by enhancing the expression and activity of 8-oxoG DNA glycosylase 1 (Ogg1), had an effect on the capacity of UVB-exposed human HaCaT keratinocytes to repair oxidative DNA damage. Here, the effects of phloroglucinol were investigated using a luciferase activity assay, reverse transcription-polymerase chain reactions, western blot analysis, and a chromatin immunoprecipitation assay. Phloroglucinol restored Ogg1 activity and decreased the formation of 8-oxoG in UVB-exposed cells. Moreover, phloroglucinol increased Ogg1 transcription and protein expression, counteracting the UVB-induced reduction in Ogg1 levels. Phloroglucinol also enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) as well as Nrf2 binding to an antioxidant response element located in the Ogg1 gene promoter. UVB exposure inhibited the phosphorylation of protein kinase B (PKB or Akt) and extracellular signal-regulated kinase (Erk), two major enzymes involved in cell protection against oxidative stress, regulating the activity of Nrf2. Akt and Erk phosphorylation was restored by phloroglucinol in the UVB-exposed keratinocytes. These results indicated that phloroglucinol attenuated UVB-induced 8-oxoG formation in keratinocytes via an Akt/Erk-dependent, Nrf2/Ogg1-mediated signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.6
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• pp.513-520
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• 2023

Cornuside is a secoiridoid glucoside compound extracted from the fruits of Cornus officinalis. Cornuside has immunomodulatory and anti-inflammatory properties; however, its potential therapeutic effects on diabetic nephropathy (DN) have not been completely explored. In this study, we established an in vitro model of DN through treating mesangial cells (MMCs) with glucose. MMCs were then treated with different concentrations of cornuside (0, 5, 10, and 30 μM). Cell viability was determined using cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays. Levels of proinflammatory cytokines, including interleukin (IL)-6, tumor necrosis factor-α, and IL-1β were examined using enzyme-linked immunosorbent assay. Reverse transcription quantitative real-time polymerase chain reaction and Western blotting were performed to detect the expression of AKT and nuclear factor-kappa B (NF-κB)-associated genes. We found that cornuside treatment significantly reduced glucose-induced increase in MMC viability and expression of pro-inflammatory cytokines. Moreover, cornuside inhibited glucose-induced phosphorylation of AKT and NF-κB inhibitor alpha, decreased the expression of proliferating cell nuclear antigen and cyclin D1, and increased the expression of p21. Our study indicates that the anti-inflammatory properties of cornuside in DN are due to AKT and NF-κB inactivation in MMCs.

• Tuberculosis and Respiratory Diseases
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• v.80 no.2
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• pp.179-186
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• 2017

Background: Although the World Health Organization (WHO) classification of lung squamous cell carcinoma (SCC) was revised in 2015, its clinical implications for lung SCC subsets remain unclear. We investigated whether the morphologic characteristics of lung SCC, including keratinization, were associated with clinical parameters and clinical outcome of patients. Methods: A total of 81 patients who underwent curative surgical resection of diagnosed lung SCC, were enrolled in this study. Attributes such as keratinization, tumor budding, single cell invasion, and nuclear size within the tumor, as well as immunohistochemistry of Bcl-xL and pS6 expressions, were evaluated. Results: The keratinizing and nonkeratinizing subtypes did not differ with respect to age, sex, TNM stage, and morphologic parameters such as nuclear diameter, tumor budding, and single cell invasion at the tumor edge. Most patients with the keratinizing subtype (98.0%) had a history of smoking, whereas the nonkeratinizing group had a relatively higher proportion of never-smokers relative to the keratinizing group (24.0% vs. 2.0%; p=0.008, chi-square test). Expression of pS6 (a surrogate marker of mammalian target of rapamycin complex 1 [mTORC1] signaling that regulates keratinocyte differentiation), and Bcl-xL (a key anti-apoptotic molecule that may inhibit keratinization), did not correlate significantly with the presence of keratinization. Patients with the keratinizing subtype had a significantly shorter overall survival (85.2 months vs. 135.7 months, p=0.010, log-rank test), and a multivariate analysis showed that keratinization was an independent, poor prognostic factor (hazard ratio, 2.389; 95% confidence interval, 1.090-5.233; p=0.030). Conclusion: In lung SCC, keratinization is associated with a poor prognosis, and might be associated with smoking.

• Tuberculosis and Respiratory Diseases
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• v.78 no.2
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• pp.99-105
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• 2015

Background: Aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, binds to a wide variety of synthetic and naturally occurring compounds. AhR is involved in the regulation of inflammatory response during acute and chronic respiratory diseases. We investigated whether nuclear receptor coactivator 7 (NCOA7) could regulate transcriptional levels of AhR target genes and inflammatory cytokines in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-treated human bronchial epithelial cells. This study was based on our previous study that NCOA7 was differentially expressed between normal and chronic obstructive pulmonary disease lung tissues. Methods: BEAS-2B and A549 cells grown under serum-free conditions were treated with or without TCDD (0.15 nM and 6.5 nM) for 24 hours after transfection of pCMV-NCOA7 isoform 4. Expression levels of cytochrome P4501A1 (CYP1A1), IL-6, and IL-8 were measured by quantitative real-time polymerase chain reaction. Results: The transcriptional activities of CYP1A1 and inflammatory cytokines were strongly induced by TCDD treatment in both BEAS-2B and A549 cell lines. The NCOA7 isoform 4 oppositely regulated the transcriptional activities of CYP1A1 and inflammatory cytokines between BEAS-2B and A549 cell lines. Conclusion: Our results suggest that NCOA7 could act as a regulator in the TCDD-AhR signaling pathway with dual roles in normal and abnormal physiological conditions.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.104-113
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• 2003

Background : Rhinovirus(RV) infections frequently trigger dyspnea and paroxysmal cough in adult patients with asthma and are the most prevalent cause of the common cold. However, the mechanisms of a RV-induced airway inflammation is unclear. Since the RV does not directly destroy the airway epithelium, it is presumed that the immune response to the RV contributes to the pathogenesis of the respiratory symptoms. In order to test this hypothesis, this study characterized the time-sequenced alterations in interleukin(IL)-8 elaboration from the human bronchial epithelial cells and evaluated the role of NF(nuclear factor)-${\kappa}B$ in the RV-induced IL-8 production by pretreating the inhibitors of NF-${\kappa}B$ activation. Methods : The ability of RV-infected human bronchial epithelial cells and BEAS-2B cells to produce the IL-8 was compared with the controls. This study infected BEAS-2B cells with the RV14 obtained from the American Type Culture Collection. The supernatants were harvested from the RV infected BEAS-2B cells and the controls at 2hr, 4hr, 6hr, 12hr, 24hr, 48hr from the inoculation time. This study measured the IL-8 concentration using the ELISA kits. In order to elucidate the role of NF-${\kappa}B$ in the RV-induced IL-8 production, the effect of the NF-${\kappa}B$ inhibitors was evaluated on RV-induced IL-8 production. Results: The BEAS-2B cells produced small amounts of IL-8 that accumulated slowly with time in the culture. The RV was a potent stimulator of the IL-8 proteins production by BEAS-2B human bronchial epithelial cells. Antioxidants, N-acetyl-L-cysteine(NAC),\ and pyrrolidine dithiocarbamate(PDTC), blocked the IL-8 elaboration by the RV-infected BEAS-2B cells, which was dose-dependent, but N-Tosyl-L-phenylalanine chloromethyl ketone(TPCK) did not. Conclusion: Some antioxidants inhibited the RV-induced IL-8 production by blocking the NF-${\kappa}B$, which may have a therapeutic potential in asthma.

• Preventive Nutrition and Food Science
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• v.21 no.4
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• pp.317-322
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• 2016

Mitochondrial biogenesis is a complex process requiring coordinated expression of nuclear and mitochondrial genomes. The peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-$1{\alpha}$) is a key regulator of mitochondrial biogenesis, and it controls mitochondrial DNA (mtDNA) replication within diverse tissues, including muscle tissue. The aim of this study was to investigate the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on mtDNA copy number and PGC-$1{\alpha}$ promoter activity in $C_2C_{12}$ muscle cells. mtDNA copy number and mRNA levels of genes related to mitochondrial biogenesis such as PGC-$1{\alpha}$, nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (Tfam) were assayed by quantitative real-time PCR. The PGC-$1{\alpha}$ promoter from -970 to +412 bp was subcloned into the pGL3-basic vector, which includes a luciferase reporter gene. Both EPA and DHA significantly increased mtDNA copy number, dose and time dependently, and up-regulated mRNA levels of PGC-$1{\alpha}$, NRF1, and Tfam. Furthermore, EPA and DHA stimulated PGC-$1{\alpha}$ promoter activity in a dose-dependent manner. These results suggest that EPA and DHA may modulate mitochondrial biogenesis, which was partially associated with increased mtDNA replication and PGC-$1{\alpha}$ gene expression in $C_2C_{12}$ muscle cells.

• Journal of Life Science
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• v.29 no.4
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• pp.436-441
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• 2019

Nelumbo nucifera, also known as sacred lotus, has mainly been used as a food throughout the Asian countries. In the present study, we prepared ethanol extracts from leaf (NL), seed (NS), and seedpod (NSP) of Nelumbo nucifera and investigated their anti-inflammatory activities in mouse macrophage RAW 264.7 cells. To evaluate the anti-inflammatory activities of NL, NS, and NSP, nitric oxide (NO) production was measured in LPS-stimulated RAW 264.7 cells. NL, NS, and NSP significantly reduced NO production in a dose-dependent manner without affecting cell viabilities. NL, NS, and NSP dramatically decreased the protein expression of pro-inflammatory genes such as iNOS and COX-2. NL, NS, and NSP also suppressed phosphorylation of MAPKs and the nuclear translocation of $NF-{\kappa}B$ p65 indicating they have their anti-inflammatory activities via regulating mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B ($NF-{\kappa}B$) pathways. In addition, we analyzed the production of reactive oxygen species (ROS) by the treatment of NL, NS, and NSP. All extracts reduced ROS production in a dose-dependent manner. And also, they increased heme oxygenase-1 (HO-1) protein expression and the nuclear translocation of nuclear respiratory factor 2 (Nrf2). In conclusion, our results suggest that Nelumbo nucifera has its anti-inflammatory activity via regulating MAPKs, $NF-{\kappa}B$, and Nrf2/HO-1 pathways.

• The Korea Journal of Herbology
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• v.34 no.6
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• pp.99-107
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• 2019

Objective : The present study was conducted to investigate the effects of Chaenomelis Fructus (CF) on the regulation of biogenesis in C2C12 mouse skeletal muscle cells. Methods : C2C12 myoblasts were differentiated into myotubes in 2% horse serum-containing medium for 5 days, and then treated with CF extract at different concentrations for 48 hr. The expression of muscle differentiation markers, myogenin and myosin heavy chain (MHC) and mitochondrial biogenesis-regulating factors, peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC1α), sirtuin1 (Sirt1), nuclear respiratory factor1 (NRF1) and transcription factor A, mitochondrial (TFAM), and the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) were determined in C2C12 myotubes by reverse transcriptase (RT)-polymerase chain reaction (RT-PCR) and western blot, respectively. The cellular glucose levels and total ATP contents were measured by cellular glucose uptake and ATP assays, respectively. Results : Treatment with CF extract (0.01, 0.02, and 0.05 mg/㎖) significantly increased the expression of MHC protein in C2C12 myotubes compared with non-treated cells. CF extract significantly increased the expression of PGC1α and TFAM in the myotubes. Also, CF extract significantly increased glucose uptake levels and ATP contents in the myotubes. Conclusion : CF extract can stimulate C2C12 myoblasts differentiation into myotubes and increase energy production through upregulation of the expression of mitochondrial biogenetic factors in C2C12 mouse skeletal muscle cell. This suggests that CF can help to improve skeletal muscle function with stimulation of the energy metabolism.

• Journal of Korean Medicine for Obesity Research
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• v.14 no.2
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• pp.55-62
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• 2014

Objective: The prevalence of metabolic syndrome and type 2 diabetes is increasing worldwide. Mitochondrial dysfunction is known to be involved in insulin resistance and obesity, researches have been increasing highly. Astragali Radix extract (ARE) or its main components have been shown to perform comparably to insulin by significantly reducing blood glucose levels in animal models however, the influence on mitochondrial dysfunction are not well understood. Methods: ARE (0.2, 0.5 and 1.0 mg/ml) or metformin (2.5 mM) were treated in C2C12 after 6 day-differentiation. The expressions of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and phosphorylation AMPK, peroxisome proliferators-activated receptror ${\gamma}$ coactivator $1{\alpha}$ ($PGC1{\alpha}$), nuclear respiratory factors 1 (NRF1), mitochondrial transcription factor (Tfam) and myosin heavy chain were detected with western blotting or polymerase chain reaction analysis. The morphological changes were also investigated. Results: ARE dose dependently increased phosphorylation of AMPK and respectively activated mRNA expressions of $PGC1{\alpha}$, NRF1 and Tfam which are mitochondrial biogenesis regulators. Furthermore, there were some morphologic differences of differentiated cells between ARE treatment and control. Conclusions: This study suggests that ARE has the potential to increase muscle mitochondrial function by activating AMPK and $PGC1{\alpha}$.

• Journal of Korean Medicine for Obesity Research
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• v.16 no.2
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• pp.109-115
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• 2016

Objectives: The all anti-obesity drugs currently approved by the US Food and Drug Administration work by reducing energy intake. In fact, no approved drug targets energy expenditure. In Korean medicine, it is known to Qi or Yang invigorating therapy could increase energy metabolism. Aconitum carmichaeli Debx (ACD) is a Yang invigorating herb, often used for treat obesity in Korean medicine. In the present study, the authors investigated the regulatory effects of ACD in energy metabolism and mitochondrial biogenesis in C2C12 skeletal muscle cells. Methods: The water extract of ACD (0.2, 0.5 and 1.0 mg/ml) were treated in differentiated C2C12 cells. The protein or mRNA levels of target genes were analyzed and mitochondrial mass were investigated. Results: ACD activated the expressions of peroxisome proliferator-activated receptor gamma coactivator 1-alpha ($PGC-1{\alpha}$), nuclear respiratory factor 1 and TFAM and increased mitochondrial mass. ACD also increased adenosin monophosphate-activated protein kinase (AMPK), and acetyl-CoA carboxylase. Conclusions: This study suggests that ACD has the potential to increase energy metabolism and mitochondrial biogenesis by activating AMPK and $PGC1{\alpha}$.