• IMMUNE NETWORK
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• v.16 no.4
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• pp.242-248
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• 2016

Thymic atrophy is a complication that results from exposure to many environmental stressors, disease treatments, and microbial challenges. Such acute stress-associated thymic loss can have a dramatic impact on the host's ability to replenish the necessary naïve T cell output to reconstitute the peripheral T cell numbers and repertoire to respond to new antigenic challenges. We have previously reported that treatment with the orexigenic hormone ghrelin results in an increase in the number and proliferation of thymocytes after dexamethasone challenge, suggesting a role for ghrelin in restraint stress-induced thymic involution and cell apoptosis and its potential use as a thymostimulatory agent. In an effort to understand how ghrelin suppresses thymic T cell apoptosis, we have examined the various signaling pathways induced by receptor-specific ghrelin stimulation using a restraint stress mouse model. In this model, stress-induced apoptosis in thymocytes was effectively blocked by ghrelin. Western blot analysis demonstrated that ghrelin prevents the cleavage of pro-apoptotic proteins such as Bim, Caspase-3, and PARP. In addition, ghrelin stimulation activates the Akt and Mitogen-activated protein kinases (MAPK) signaling pathways in a time/dose-dependent manner. Moreover, we also revealed the involvement of the FoxO3a pathway in the phosphorylation of Akt and ERK1/2. Together, these findings suggest that ghrelin inhibits apoptosis by modulating the stress-induced apoptotic signal pathway in the restraint-induced thymic apoptosis.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.354-360
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• 2020

The hair cycle (anagen, catagen, and telogen) is regulated by the interaction between mesenchymal cells and epithelial cells in the hair follicles. The proliferation of dermal papilla cells (DPCs), mesenchymal-derived fibroblasts, has emerged as a target for the regulation of the hair cycle. Here, we show that vanillic acid, a phenolic acid from wheat bran, promotes the proliferation of DPCs via a PI3K/Akt/Wnt/β-catenin dependent mechanism. Vanillic acid promoted the proliferation of DPCs, accompanied by increased levels of cell-cycle proteins cyclin D1, CDK6, and Cdc2 p34. Vanillic acid also increased the levels of phospho(ser473)-Akt, phospho(ser780)-pRB, and phospho(thr37/46)-4EBP1 in a time-dependent manner. Wortmannin, an inhibitor of the PI3K/Akt pathway, attenuated the vanillic acid-mediated proliferation of DPCs. Vanillic acid-induced progression of the cell-cycle was also suppressed by wortmannin. Moreover, vanillic acid increased the levels of Wnt/β-catenin proteins, such as phospho(ser9)-glycogen synthase kinase-3β, phospho(ser552)-β-catenin, and phospho(ser675)-β-catenin. We found that vanillic acid increased the levels of cyclin D1 and Cox-2, which are target genes of β-catenin, and these changes were inhibited by wortmannin. To investigate whether vanillic acid affects the downregulation of β-catenin by dihydrotestosterone (DHT), implicated in the development of androgenetic alopecia, DPCs were stimulated with DHT in the presence and absence of vanillic acid for 24 h. Western blotting and confocal microscopy analyses showed that the decreased level of β-catenin after the incubation with DHT was reversed by vanillic acid. These results suggest that vanillic acid could stimulate anagen and alleviate hair loss by activating the PI3K/Akt and Wnt/β-catenin pathways in DPCs.

• The Korea Journal of Herbology
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• v.35 no.4
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• pp.9-16
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• 2020

Objective : To identify the effects of the water extract of Liriope platyphylla tuber (Liriopis tuber, LT) on the activation of astocytes, we investigated the regulatory effects of LT extract on H₂O₂-induced oxidative damage in C6 rat astrocytes. Methods : LT extract was extracted with boiling water. C6 cell line were treated with LT extract at 1, 2, and 3 mg/㎖ or without for 30 min and then stimulated with H₂O₂ at 5 ㎛ for 24 hr. The cell viability was measured by MTT assay. The expression of glial fibrillary acidic protein (GFAP), signal transducer and activator of transcription 3 (STAT3), phospho-STAT3 (pSTAT3), cyclooxygenase (COX-2), Nuclear factor-κB (NF-κB), superoxide dismutase 2 (SOD2), heme oxygenase-1 (HO-1), catalase, Akt, phospho-Akt (p-Akt) phosphoinositide 3-kinases (PI3K), and protein kinase C alpha (PKCα) proteins were determined by Western blot, respectively. GFAP expression was also observed with immunocytochemistry under a fluorescence microscope. Results : LT extract induced cell proliferation in H₂O₂-stimulated C6 cells. LT extract significantly inhibited the expression of GFAP, NF-κB and COX-2 and increased the expression of HO-1 and the phosphorylation of STAT3 in H₂O₂-stimulated C6 cells. LT extract also significantly increased the phosphorylation of Akt and decreased the expression of PKCα in a dose-dependent manner in H₂O₂-stimulated C6 cells. Conclusions : LT extract can regulate H₂O₂-induced activation of astrocytes through inhibiting the expression of NF-κB, COX-2 and regulating Akt / HO-1, STAT3 or PKCα signaling pathway.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.573-582
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• 2022

In order to develop samultang with reduced side effects, modified samultang using omija was oral administered to rats with ovarian resection, and changes in evaluation indicators of functional efficacy in women's menopause were measured. In weight gain, relative weight of uterus and vagina, blood lipid-related indicators, and changes in blood estradiol, there was no statistically significant improvement effect in modified Samultang compared to the control group. However, the expression of estrogen receptor alpha and beta in intrauterine tissue tended to increase, and the expression of phosphorylated ERK, which is known to be involved in estrogen receptor signaling, showed a significant increase in activation in ERK and AKT. The expression amount of phosphorylation AKT was not significant, but showed an increasing tendency. Even though the test substance was administered in a relatively small dose, it is judged that the test substance modified Samultang has the ability to activate estrogen receptor. In the future, it is expected that it can be used as a useful natural mixture to show the efficacy of samultang with fewer gastrointestinal disorders.

• Journal of Life Science
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• v.33 no.4
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• pp.343-348
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• 2023

Acne is one of the most common skin diseases, mainly occurring in adolescence. The pathophysiology of acne involves not only hormonal, genetic and environmental factors, but also other factors including hyperseborrhea, inflammation, over-keratinization of follicular keratinocytes and overgrowth of Cutibacterium acnes (C. acnes). Cannabidiol (CBD) is known to relieve pain, stress and inflammation. Moreover, cannabis extracts containing CBD have been reported to be effective in treating acne. However, the therapeutic effect of CBD on acne remains unclear. Therefore, this study aimed to investigate the effect and mechanism of CBD on lipogenesis in SEB-1 sebocytes. We treated sebocytes with CBD and found that it not only inhibited lipid synthesis, but also inhibited cell proliferation by inducing apoptosis. We then demonstrated that sterol response element-binding protein-1 (SREBP-1) mediates the inhibitory effect of CBD on lipogenesis. Furthermore, Akt and adenosine monophosphate-activated protein kinase (AMPK), upstream regulators of SREBP-1, were regulated by CBD treatment. Taken together, our studies demonstrate that CBD inhibits adipogenesis by regulating the Akt/AMPK-SREBP-1 signaling pathway, providing potential for use as a therapeutic agent for acne. Further research is needed to confirm the effect of CBD on inflammation caused by hyperkeratosis, which will increase the possibility of using CBD for acne treatment.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.233-241
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• 2007

Purpose: We examined the effect of the dual EGFR/HER2 tyrosine kinase inhibitor, GW572016, on EGFR/HER2 receptor phosphorylation, inhibition of downstream signaling and radiosensitization in either an EGFR or HER2 overexpressing human breast cancer xenograft. Materials and Methods: We established SCID mice xenografts from 4 human breast cancer cell line that overexpressed EGFR or HER 2 (SUM 102, SUM 149, SUM 185, SUM 225). Two series of xenografts were established. One series was established for determining inhibition of the EGFR/HER2 receptor and downstream signaling activities by GW572016. The other series was established for determining the radiosensitization effect of GW572016. Inhibition of the receptor and downstream signaling proteins were measured by the use of immunoprecipitation and Western blotting. For determining the in vivo radiosensitization effect of GW572016, we compared tumor growth delay curves in the following four treatment arms: a) control; b) GW572016 alone; c) radiotherapy (RT) alone; d) GW572016 and RT. Results: GW572016 inhibited EGFR, HER2 receptor phosphorylation in SUM 149 and SUM 185 xenografts. In addition, the p44/42 MAPK (ERK 1/2) downstream signaling pathway was inactivated by GW572016 in the SUM 185 xenograft. In the SUM 225 xenograft, we could not observe inhibition of HER2 receptor phosphorylation by GW572016; both p44/42 MAPK (Erk1/2) and Akt downstream signal protein phosphorylation were inhibited by GW572016. GW572016 inhibited growth of the tumor xenograft of SUM 149 and SUM 185. The combination of GW572016 and RT enhanced growth inhibition greater than that with GW572016 alone or with RT alone in the SUM 149 xenograft. GW572016 appears to act as an in vivo radiosensitizer. Conclusion: GW572016 inhibited EGFR/HER2 receptor phosphorylation and downstream signaling pathway proteins. GW572016 modestly inhibited the growth of tumor in the SUM 185 xenograft and showed radiosensitization in the SUM 149 xenograft. Our results suggest that a better predictor of radiation response would be inhibition of a crucial signaling pathway than inhibition of a receptor.

• Nutrition Research and Practice
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• v.7 no.6
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• pp.439-445
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• 2013

It has been shown that dysregulation of IGF-1 signaling is associated with tumor incidence and progression, whereas blockade of the signaling can effectively inhibit carcinogenesis. Although several mechanisms of anticancer activity of quercetin were proposed, molecular targets of quercetin have not been identified yet. Hence, we assessed the effect of quercetin on IGF-1 signaling inhibition in BK5.IGF-1 transgenic (Tg) mice, which over-expresses IGF-1 in the skin epidermis. A quercetin diet (0.02% wt/wt) for 20 weeks remarkably delayed the incidence of skin tumor by 2 weeks and reduced tumor multiplicity by 35% in a 7,12-dimethylbenz(a)anthracene (DMBA)-tetradecanoyl phorbol-13-acetate (TPA) two stage mouse skin carcinogenesis protocol. Moreover, skin hyperplasia in Tg mice was significantly inhibited by a quercetin supplementation. Further analysis of the MT1/2 skin papilloma cell line showed that a quercetin treatment dose dependently suppressed IGF-1 induced phosphorylation of the IGF-1 receptor (IGF-1R), insulin receptor substrate (IRS)-1, Akt and S6K; however, had no effect on the phosphorylation of PTEN. Additionally, the quercetin treatment inhibited IGF-1 stimulated cell proliferation in a dose dependent manner. Taken together, these data suggest that quercetin has a potent anticancer activity through the inhibition of IGF-1 signaling.

• BMB Reports
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• v.51 no.8
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• pp.400-405
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• 2018

Chronic stress induces neuronal cell death, which can cause nervous system disorders including Parkinson's disease and Alzheimer's disease. In this study, we evaluated the neuroprotective effects of Clematis terniflora extract (CTE) against corticosterone-induced apoptosis in rat pheochromocytoma (PC12) cells, and also investigated the underlying molecular mechanisms. At concentrations of 300 and $500{\mu}g/ml$, CTE significantly decreased apoptotic cell death and mitochondrial damage induced by $200{\mu}M$ corticosterone. CTE decreased the expression levels of endoplasmic reticulum (ER) stress proteins GRP78, GADD153, and mitochondrial damage-related protein BAD, suggesting that it downregulates ER stress evoked by corticosterone. Furthermore, our results suggested that these protective effects were mediated by the upregulation of p-AKT and p-ERK1/2, which are involved in cell survival signaling. Collectively, our results indicate that CTE can lessen neural damage caused by chronic stress.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.302-307
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• 2011

Peptidoglycan (PGN) is detected in inflammatory cell-rich regions of human atheromatous plaques. The present study investigated the effects of PGN on CC chemokine ligand 3 (CCL3) expression, which is elevated in the atherosclerotic arteries, and determined cellular factors involved in PGN-mediated CCL3 up-regulation in mononuclear cells, with the goal of understanding the molecular mechanisms of inflammatory responses to bacterial pathogen-associated molecular patterns in diseased arteries. Exposure of human monocytic leukemia THP-1 cells to PGN resulted in enhanced secretion of CCL3 and profound induction of the CCL3 gene transcript. Both events were abrogated by oxidized 1-palmitoyl-2-arachidonosyl-sn-phosphatidylcholine, an inhibitor of Toll-like receptors 2/4. Pharmacological inhibitors such as U0126, SP6001250, Akt inhibitor IV, rapamycin, RO318220, diphenyleneiodonium chloride, and N-acetylcysteine also significantly attenuated PGN-mediated CCL3 up-regulation. However, polymyxin B, LY294002, and SB202190 did not influence CCL3 expression. We propose that PGN contributes to enhanced CCL3 expression in atherosclerotic plaques and that Toll-like receptors (TLR2), Akt, mTOR, mitogen-activated protein kinase, and reactive oxygen species are involved in that process.

• Natural Product Sciences
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• v.26 no.3
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• pp.221-229
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• 2020

This study was undertaken to investigate the protective effect of rice bran oil (RBO) on amyloid β protein (Aβ) (25-35)-induced memory impairment and brain damage in an ICR mouse model. Memory impairment was produced by intracerebroventricular microinjection of 15 nmol Aβ (25-35) and assessed using the passive avoidance test. Treatment with RBO at 0.1, 0.5, or 1 mL/kg (p.o. daily for 8 days) protected against Aβ (25-35)-induced memory impairment. Furthermore, Aβ (25-35)-induced decreases in glutathione and increases in lipid peroxidation and cholinesterase activity in brain tissue were inhibited by RBO, and Aβ (25-35)-induced increases of phosphorylated mitogen-activated protein kinases (MAPKs) and inflammatory factors, and changes in the levels of apoptosis-related proteins were significantly inhibited by RBO. Furthermore, Aβ (25-35) suppressed the PI3K/Akt pathway and the phosphorylation of CREB, but increased phosphorylation of tau (p-tau) in mice brain; these effects were significantly inhibited by administration of RBO. These results suggest that RBO inhibits Aβ (25-35)-induced memory impairment by inducing anti-apoptotic and anti-inflammatory effects, promoting PI3K/Akt/CREB signaling, and thus, inhibiting p-tau formation.