• Research in Vestibular Science
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• v.17 no.4
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• pp.142-151
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• 2018

Objectives: Excitability o medial vestibular nucleus (MVN) in the brainstem can be affected by changes in the arterial blood pressure. Several animal studies have demonstrated that acute hypotension results in the alteration of multiunit activities and expression of cFos protein in the MVN. In the field of extracellular electrophysiological recording, tetrode technology and spike sorting algorithms can easily identify single unit activity from multiunit activities in the brain. However, detailed properties of electrophysiological changes in single unit of the MVN during acute hypotension have been unknown. Methods: Therefore, we applied tetrode techniques and electrophysiological characterization methods to know the effect of acute hypotension on single unit activities of the MVN of rats. Results: Two or 3 types of unit could be classified according to the morphology of spikes and firing properties of neurons. Acute hypotension elicited 4 types of changes in spontaneous firing of single unit in the MVN. Most of these neurons showed excitatory responses for about within 1 minute after the induction of acute hypotension and then returned to the baseline activity 10 minutes after the injection of sodium nitroprusside. There was also gradual increase in spontaneous firing in some units. In contrast small proportion of units showed rapid reduction of firing rate just after acute hypotension. Conclusions: Therefore, application of tetrode technology and spike sorting algorithms is another method for the monitoring of electrical activity of vestibular nuclear during acute hypotension.

• BMB Reports
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• v.54 no.5
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• pp.266-271
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• 2021

Estrogen-related receptor γ (ERRγ), a member of the orphan nuclear receptor family, is a key mediator in cellular metabolic processes and energy homeostasis. Therefore, ERRγ has become an attractive target for treating diverse metabolic disorders. We recently reported that ERRγ acts as a negative regulator of osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand (RANKL). In the present study, we explored the effects of an ERRγ-specific modulator, GSK5182, on ERRγ-regulated osteoclast differentiation and survival. Interestingly, GSK5182 increased ERRγ protein levels much as does GSK4716, which is an ERRγ agonist. GSK5182 inhibited osteoclast generation from bone-marrow-derived macrophages without affecting cytotoxicity. GSK5182 also attenuated RANKL-mediated expression of cFos and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), pivotal transcription factors for osteoclastogenesis. Arrested osteoclast differentiation was associated with reduced RANK expression, but not with the M-CSF receptor, c-Fms. GSK5182 strongly blocked the phosphorylation of IκBα, c-Jun N-terminal kinase, and extracellular signal-regulated kinase in response to RANKL. GSK5182 also suppressed NF-κB promoter activity in a dose-dependent manner. In addition to osteoclastogenesis, GSK5182 accelerated osteoclast apoptosis by caspase-3 activation. Together, these results suggest that GSK5182, a synthetic ERRγ modulator, may have potential in treating disorders related to bone resorption.

• Journal of Life Science
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• v.26 no.1
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• pp.34-41
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• 2016

Black chokeberries (scientific name Aronia melanocarpa) have been reported to have major effects due to anti-oxidant, anti-inflammatory, and anti-cancer capabilities. In this study, we investigated the anti- wrinkle effects of A. melanocarpa, including collagenase inhibition effects and their molecular biological mechanisms, such as oxidative stress-induced matrix metalloproteinase (MMP), mitogen-activated protein (MAP) kinase, and activator protein (AP)-1 expression and/or phosphorylation. In collagenase inhibition activity, the ethyl acetate fraction of black chokeberry (AE) was 77.2% at a concentration of 500 μg/ml, which was a significant result compared to that of Epigallocatechin gallate (positive control, 83.9% in 500 μg/ml). In the reactive oxygen species (ROS) assay, the AE produced 78% of ROS in 10 μg/ml and 70% of ROS in 75 μg/ml, which was a much lower percentage than the ROS production of H₂O₂-induced CCRF S-180II cells. In the MTT assay, cell viability was increased dose-dependently with AE in H₂O₂-induced cells. In protein expression by western blot assay, the AE suppressed the expression and phosphorylation of MMPs (MMP-1, -3, -9), MAPK (ERK, JNK, and p38), and AP-1 (c-Fos and c-Jun), and expressed the pro-collagen type I in H₂O₂-induced cells. These results suggest that black chokeberries have anti-wrinkle and collagen-production effects, and they may be used in applications for material development in the functional food and cosmetic industries.

• Environmental Mutagens and Carcinogens
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• v.26 no.1
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• pp.12-19
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• 2006

Cadmium, a human carcinogen, can induce toxicity in various cell lines and organs. Despite extensive research, the mechanisms of cadmium-induced cell toxicity and estrogenic potential in human are not clear. This study was performed to investigate cadmium-induced toxicity on human breast cancer cells: MCF-7 cells, an estrogen receptor (ER) positive breast cancer cells, and MDA-MB-231 cells, an ER negative breast cancer cells. MCF-7 cells was proved to be more sensitive than the other cell lines (IC50 = $50\;{\mu}M$ at MCF-7 cells and $120{\mu}M$ at MDA-MB-231). The expression of JNK and AP-1 transcription factors such as c-Jun and c-Fos dependent transcription were increased by cadmium treatment. Inhibition of ER activation by ER antagonist (tamoxifen or ICI 182,780) significantly recovered the viablity and inhibited apoptotic cell death. This suggested that cadmium-induced cell death in ER (+) cells was mediated by JNK/AP-1 pathway and this pathway was more stimulated by ER activated by cadmium. Co-treatment of antioxidants such as selenium (Se), butylated hydroxyanisole (BHA), glutathione (GSH), or N-acetyl-L-cysteine (NAC) recovered the cadmium-induced cell death in MCF-7 cells. Cadmium-induced lipid peroxidation was decreased by GSH, NAC, or BHA in MCF-7 cells. The expression of SOD protein was decreased by cadmium ($100{\mu}M$) but recovered by GSH, NAC, BHA, or Se. Our data showed that the cadmium-induced cell toxicity in human breast cancer cells could be protected by the antioxidants (Se, BHA, NAC, GSH, or NAC) and ER antagonist (tamoxifen or ICI 182,780). Therefore, toxicity of cadmium in breast cancer were mediated by oxidative stress and $ER{\alpha}$.

• BMB Reports
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• v.53 no.4
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• pp.218-222
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• 2020

Excessive and hyperactive osteoclast activity causes bone diseases such as osteoporosis and periodontitis. Thus, the regulation of osteoclast differentiation has clinical implications. We recently reported that dehydrocostus lactone (DL) inhibits osteoclast differentiation by regulating a nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), but the underlying mechanism remains to be elucidated. Here we demonstrated that DL inhibits NFATc1 by regulating nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and nuclear factor-erythroid 2-related factor 2 (Nrf2). DL attenuated IκBα phosphorylation and p65 nuclear translocation as well as decreased the expression of NF-κB target genes and c-Fos. It also inhibited c-Jun N-terminal kinase (JNK) but not p38 or extracellular signal-regulated kinase. The reporter assay revealed that DL inhibits NF-κB and AP-1 activation. In addition, DL reduced reactive oxygen species either by scavenging them or by activating Nrf2. The DL inhibition of NFATc1 expression and osteoclast differentiation was less effective in Nrf2-deficient cells. Collectively, these results suggest that DL regulates NFATc1 by inhibiting NF-κB and AP-1 via down-regulation of IκB kinase and JNK as well as by activating Nrf2, and thereby attenuates osteoclast differentiation.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.107-115
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• 2018

Background: Depression is one of the most commonly diagnosed neuropsychiatric diseases, but the underlying mechanism and medicine are not well-known. Although Panax ginseng has been reported to exert protective effects in various neurological studies, little information is available regarding its antidepressant effects. Methods: Here, we examined the antidepressant effect and underlying mechanism of P. ginseng extract (PGE) in a chronic restraint stress (CRS)-induced depression model in mice. Results: Oral administration of PGE for 14 d decreased immobility (depression-like behaviors) time in forced swim and tail suspended tests after CRS induction, which corresponded with attenuation of the levels of serum adrenocorticotropic hormone and corticosterone, as well as attenuated c-Fos expression in the amygdala. PGE enhanced messenger RNA expression level of brain-derived neurotrophic factor but ameliorated microglial activation and neuroinflammation (the level of messenger RNA and protein expression of cyclooxygenase-2 and inducible nitric oxide synthase) in the amygdala of mice after CRS induction. Interestingly, 14-d treatment with celecoxib, a selective cyclooxygenase-2 inhibitor, and $N_{\omega}$-nitro-L-arginine methyl ester hydrochloride, a selective inducible nitric oxide synthase inhibitor, attenuated depression-like behaviors after CRS induction. Additionally, PGE inhibited the upregulation of the nuclear factor erythroid 2 related factor 2 and heme oxygenase-1 pathways. Conclusion: Taken together, our findings suggest that PGE exerts antidepressant-like effect of CRS-induced depression by antineuroinflammatory and antioxidant (nuclear factor erythroid 2 related factor 2/heme oxygenase-1 activation) activities by inhibiting the hypothalamo-pituitary-adrenal axis mechanism. Further studies are needed to evaluate the potential of components of P. ginseng as an alternative treatment of depression, including clinical trial evaluation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.6
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• pp.869-873
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• 2012

Balance between bone-forming osteoblasts and bone-resorbing osteoclasts is important in bone homeostasis. Unusual balance between bone-forming osteoblasts and bone-resorbing osteoclasts leads to bone diseases, such as osteoporosis. Saururus chinensis has been widely used in oriental medicine. Saururus chinensis has been known that has antioxidant and anticancer effect. But, the effect of Saururus chinensis in osteoclast differentation remains unknown. We examined the effect of Saururus chinensis in receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL)-induced osteoclast differentiation. From the results of our study, we found that saururus chinensis clearly inhibited RANKL-induced osteoclast differentiation in bone marrow macrophages (BMM) in a dose dependent manner without toxicity. Saururus chinensis inhibited the phosphorylation of JNK, P38, AKT, and ERK induced by RANKL. The mRNA expression of NFATc1, TRAP, and OSCAR induced by RANKL was inhibited by Saururus chinensis treatment. Moreover Saururus chinensis suppressed the protein expression of c-Fos and NFATc1 in BMMs treated with RANKL. These results suggest that Saururus chinensis may be a useful drug in the treatment of bone-related disease.