• Molecules and Cells
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• 제46권7호
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• pp.441-450
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• 2023

β-Catenin (Ctnnb1) has been shown to play critical roles in the development and maintenance of epithelial cells, including the retinal pigment epithelium (RPE). Ctnnb1 is not only a component of intercellular junctions in the epithelium, it also functions as a transcriptional regulator in the Wnt signaling pathway. To identify which of its functional modalities is critically involved in mouse RPE development and maintenance, we varied Ctnnb1 gene content and activity in mouse RPE lineage cells and tested their impacts on mouse eye development. We found that a Ctnnb1 double mutant (Ctnnb1^dm), which exhibits impaired transcriptional activity, could not replace Ctnnb1 in the RPE, whereas Ctnnb1^Y654E, which has reduced affinity for the junctions, could do so. Expression of the constitutively active Ctnnb1^∆ex3 mutant also suppressed the development of RPE, instead facilitating a ciliary cell fate. However, the post-mitotic or mature RPE was insensitive to the loss, inactivation, or constitutive activation of Ctnnb1. Collectively, our results suggest that Ctnnb1 should be maintained within an optimal range to specify RPE through transcriptional regulation of Wnt target genes in the optic neuroepithelium.

• 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.

• 생약학회지
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• 제52권1호
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• pp.34-40
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• 2021

Proliferation and maintain of dermal papilla during progression of hair-cycle are crucial to the duration of anagen and regulated by diverse signaling pathway such as PI3K/Akt/Wnt/β-catenin pathway. In this study, we investigated the effects and mechanisms of Viola verecunda on dermal papilla cells. Treatment of dermal papilla cells with whole plant extract of V. verecunda resulted in cell proliferation, which was accompanied by up-regulation of cyclin D1, phospho (ser780)-pRB and cdc2 p34, and down-regulation of p27kip1. V. verecunda extract also promoted the levels of phospho (ser473)-Akt and phospho (ser780)-pRB in a time-dependent manner. Inhibition of PI3K/Akt by Wortmannin suppressed progression of cell-cycle, thereby attenuated the increases in proliferation of dermal papilla cells by V. verecunda extract. We further investigated Wnt/β-catenin pathway with respect to the effects of V. verecunda extract on the proliferation of dermal papilla cells. Treatment with V. verecunda extract results in up-regulation of Wnt/β-catenin proteins such as phospho (ser9)-GSKβ, phospho (ser552)-β-catenin and phospho (ser675)-β-catenin. In addition, Wortmannin abrogated V. verecunda extract mediated up-regulation of cdc2 p34 and down-regulation of p27kip1. These finding reveal that the proliferative effect of V. verecunda mediated by alteration of cell-cycle via activating PI3K/Akt/Wnt pathway in dermal papilla cells.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2005년도 춘계 국제심포지엄 및 학술대회
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• pp.189-189
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• 2005

• 생약학회지
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• 제52권4호
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• pp.234-241
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• 2021

Dermal papilla cells (DPCs) are present throughout the hair cycle and play an essential role in hair cycle and hair growth. In this study, we investigated the effect of Carex dispalata on the activation of anagen pathway in DPCs. C. dispalata extract increased the proliferation of DPCs and induced changes in the levels of cell cycle-related proteins. To elucidate the mechanism by which C. dispalata extract stimulates the anagen pathway related to the proliferation of DPCs, we evaluated the effect of C. dispalata extract on the activation of Akt signaling. The increase in the level of phospho-Akt by C. dispalata extract was inhibited by PI3K inhibitor (wortmannin). Wortmannin reduced the effects of C. dispalata extract on the levels of cell cycle-related proteins and proliferation of DPCs. C. dispalata extract increased the levels of Wnt/β-catenin proteins. Wnt/β-catenin inhibitor (XAV939) inhibited changes in cell cycle, cell cycle-related proteins, Wnt/β-catenin proteins, and proliferation induced by C. dispalata extract. C. dispalata extract increased the level of autophagy protein (LC3I/II), and this change was inhibited by XAV939. These results suggest that C. dispalata extract can activate PI3K/Akt, Wnt/β-catenin, and autophagy pathways in DPCs to induce cell proliferation, and thereby promote hair growth phase.

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.812-827
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• 2024

Phloroglucinol (PG) is one of the abundant isomeric benzenetriols in brown algae. Due to its polyphenolic structure, PG exhibits various biological activities. However, the impact of PG on anagen signaling and oxidative stress in human dermal papilla cells (HDPCs) is unknown. In this study, we investigated the therapeutic potential of PG for improving hair loss. A non-cytotoxic concentration of PG increased anagen-inductive genes and transcriptional activities of β-Catenin. Since several anagen-inductive genes are regulated by β-Catenin, further experiments were performed to elucidate the molecular mechanism by which PG upregulates anagen signaling. Various biochemical analyses revealed that PG upregulated β-Catenin signaling without affecting the expression of Wnt. In particular, PG elevated the phosphorylation of protein kinase B (AKT), leading to an increase in the inhibitory phosphorylation of glycogen synthase kinase 3 beta (GSK3β) at serine 9. Treatment with the selective phosphoinositide 3-kinase/AKT inhibitor, LY294002, restored the increased AKT/GSK3β/β-Catenin signaling and anagen-inductive proteins induced by PG. Moreover, conditioned medium from PG-treated HDPCs promoted the proliferation and migration of human epidermal keratinocytes via the AKT signaling pathway. Subsequently, we assessed the antioxidant activities of PG. PG ameliorated the elevated oxidative stress markers and improved the decreased anagen signaling in hydrogen peroxide (H₂O₂)-induced HDPCs. The senescence-associated β-galactosidase staining assay also demonstrated that the antioxidant abilities of PG effectively mitigated H₂O₂-induced senescence. Overall, these results indicate that PG potentially enhances anagen signaling and improves oxidative stress-induced cellular damage in HDPCs. Therefore, PG can be employed as a novel therapeutic component to ameliorate hair loss symptoms.

• Biomolecules & Therapeutics
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• 제28권4호
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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.

• Journal of Microbiology and Biotechnology
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• 제31권11호
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• pp.1559-1567
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• 2021

The root bark of Morus alba L. has cytotoxic activity against several types of cancer cells. However, little is known about its chemopreventive mechanisms and bioactive metabolites. In this study, we showed that M. alba L. root bark extracts (MRBE) suppressed β-catenin response transcription (CRT), which is aberrantly activated in various cancers, by promoting the degradation of β-catenin. In addition, MRBE repressed the expression of the β-catenin/T-cell factor (TCF)-dependent genes, c-myc and cyclin D1, thus inhibiting the proliferation of RPMI-8226 multiple myeloma (MM) cells. MRBE induced apoptosis in MM cells, as evidenced by the increase in the population of annexin VFITC-positive cells and caspase-3/7 activity. We identified ursolic acid in MRBE through LC/mass spectrum (MS) and observed that it also decreased intracellular β-catenin, c-myc, and cyclin D1 levels. Furthermore, it suppressed the proliferation of RPMI-8226 cells by stimulating cell cycle arrest and apoptosis. These findings suggest that MRBE and its active ingredient, ursolic acid, exert antiproliferative activity by promoting the degradation of β-catenin and may have significant chemopreventive potential against MM.

• BMB Reports
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• 제53권8호
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• pp.425-430
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• 2020

Tumor necrosis factor-inducible gene 6 protein (TSG-6) is a cytokine secreted by mesenchymal stem cells (MSCs) and regulates MSC stemness. We previously reported that TSG-6 changes primary human hepatic stellate cells (pHSCs) into stem-like cells by activating yes-associated protein-1 (YAP-1). However, the molecular mechanism behind the reprogramming action of TSG-6 in pHSCs remains unknown. Cluster of differentiation 44 (CD44) is a transmembrane protein that has multiple functions depending on the ligand it is binding, and it is involved in various signaling pathways, including the Wnt/β-catenin pathway. Given that β-catenin influences stemness and acts downstream of CD44, we hypothesized that TSG-6 interacts with the CD44 receptor and stimulates β-catenin to activate YAP-1 during TSG-6-mediated transdifferentiation of HSCs. Immunoprecipitation assays showed the interaction of TSG-6 with CD44, and immunofluorescence staining analyses revealed the colocalization of TSG-6 and CD44 at the plasma membrane of TSG-6-treated pHSCs. In addition, TSG-6 treatment upregulated the inactive form of phosphorylated glycogen synthase kinase (GSK)-3β, which is a negative regulator of β-catenin, and promoted nuclear accumulation of active/nonphosphorylated β-catenin, eventually leading to the activation of YAP-1. However, CD44 suppression in pHSCs following CD44 siRNA treatment blocked the activation of β-catenin and YAP-1, which inhibited the transition of TSG-6-treated HSCs into stem-like cells. Therefore, these findings demonstrate that TSG-6 interacts with CD44 and activates β-catenin and YAP-1 during the conversion of TSG-6-treated pHSCs into stem-like cells, suggesting that this novel pathway is an effective therapeutic target for controlling liver disease.

• Nutrition Research and Practice
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• 제16권2호
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• pp.161-172
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• 2022

BACKGROUND/OBJECTIVES: Colorectal cancer (CRC) is the third most common cancer worldwide and has a high recurrence rate, which is associated with cancer stem cells (CSCs). β-carotene (BC) possesses antioxidant activity and several anticancer mechanisms. However, no investigation has examined its effect on colon cancer stemness. MATERIALS/METHODS: CD133⁺CD44⁺ HCT116 and CD133⁺CD44⁺ HT-29 cells were isolated and analyzed their self-renewal capacity by clonogenic and sphere formation assays. Expressions of several CSCs markers and Wnt/β-catenin signaling were examined. In addition, CD133⁺CD44⁺ HCT116 cells were subcutaneously injected in xenograft mice and analyzed the effect of BC on tumor formation, tumor volume, and CSCs markers in tumors. RESULTS: BC inhibited self-renewal capacity and CSC markers, including CD44, CD133, ALDH1A1, NOTCH1, Sox2, and β-catenin in vitro. The effects of BC on CSC markers were confirmed in primary cells isolated from human CRC tumors. BC supplementation decreased the number and size of tumors and delayed the tumor-onset time in xenograft mice injected with CD133⁺CD44⁺ HCT116 cells. The inhibitory effect of BC on CSC markers and the Wnt/β-catenin signaling pathway in tumors was confirmed in vivo as well. CONCLUSIONS: These results suggest that BC may be a potential therapeutic agent for colon cancer by targeting colon CSCs.