• Biomolecules & Therapeutics
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• v.28 no.5
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• pp.423-430
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• 2020

Telmisartan is an angiotensin-II receptor blocker and acts as a selective modulator of peroxisome proliferator-activated receptor gamma (PPARγ). Several studies have demonstrated that telmisartan ameliorates depression and memory dysfunction and reduces brain inflammation. We hypothesized that the beneficial effects of telmisartan on brain could be due to modulation of the blood-brain barrier (BBB) function. Here, we examined the effect of telmisartan on tumor necrosis factor alpha (TNF-α)-induced expression of intercellular adhesion molecule 1 (ICAM-1) which plays an important role in leukocyte transcytosis through the BBB. Telmisartan blocked TNF-α-induced ICAM-1 expression and leukocyte adhesion in U87MG human glioma cells but showed no effect on human brain microvascular endothelial cells. In U87MG cells, a PPAR antagonist, GW9662 did not block the effect of telmisartan on ICAM1 expression but rather potentiated. Moreover, GW9662 caused no change in TNF-α-induced ICAM-1 expression, suggesting no implication of PPARγ in the telmisartan effect. Further studies showed that telmisartan blocked TNF-α-induced activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and nuclear factorkappa B (NF-κB). In contrast, inhibitors of JNK, ERK1/2 and NF-κB but not p38, blocked ICAM-1 expression induced by TNF-α. Thus, our findings suggest that the beneficial effect of telmisartan is likely due to the reduction of astrocytic ICAM1 expression and leukocytes adhesion to astrocytes, and that this response was mediated by the inhibition of JNK/ERK1/2/NF-κB activation and in the PPAR-independent manner. In conclusion, this study enhances our understanding of the mechanism by which telmisartan exerts the beneficial brain function.

• Biomolecules & Therapeutics
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• v.31 no.5
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• pp.515-525
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• 2023

The most common heart valve disorder is calcific aortic valve stenosis (CAVS), which is characterized by a narrowing of the aortic valve. Treatment with the drug molecule, in addition to surgical and transcatheter valve replacement, is the primary focus of researchers in this field. The purpose of this study is to determine whether niclosamide can reduce calcification in aortic valve interstitial cells (VICs). To induce calcification, cells were treated with a pro-calcifying medium (PCM). Different concentrations of niclosamide were added to the PCM-treated cells, and the level of calcification, mRNA, and protein expression of calcification markers was measured. Niclosamide inhibited aortic valve calcification as observed from reduced alizarin red s staining in niclosamide treated VICs and also decreased the mRNA and protein expressions of calcification-specific markers: runt-related transcription factor 2 and osteopontin. Niclosamide also reduced the formation of reactive oxygen species, NADPH oxidase activity and the expression of Nox2 and p22^phox. Furthermore, in calcified VICs, niclosamide inhibited the expression of β-catenin and phosphorylated glycogen synthase kinase (GSK-3β), as well as the phosphorylation of AKT and ERK. Taken together, our findings suggest that niclosamide may alleviate PCM-induced calcification, at least in part, by targeting oxidative stress mediated GSK-3β/β-catenin signaling pathway via inhibiting activation of AKT and ERK, and may be a potential treatment for CAVS.

• Biomolecules & Therapeutics
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• v.31 no.5
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• pp.550-558
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• 2023

Hair loss is a common condition that can have a negative impact on an individual's quality of life. The severe side effects and the low efficacy of current hair loss medications create unmet needs in the field of hair loss treatment. Hyaluronan and Proteoglycan Link Protein 1 (HAPLN1), one of the components of the extracellular matrix, has been shown to play a role in maintaining its integrity. HAPLN1 was examined for its ability to impact hair growth with less side effects than existing hair loss treatments. HAPLN1 was predominantly expressed in the anagen phase in three stages of the hair growth cycle in mice and promotes the proliferation of human hair matrix cells. Also, recombinant human HAPLN1 (rhHAPLN1) was shown to selectively increase the levels of transforming growth factor-β receptor II in human hair matrix cells. Furthermore, we observed concomitant activation of the ERK1/2 signaling pathway following treatment with rhHAPLN1. Our results indicate that rhHAPLN1 elicits its cell proliferation effect via the TGF-β2-induced ERK1/2 pathway. The prompt entering of the hair follicles into the anagen phase was observed in the rhHAPLN1-treated group, compared to the vehicle-treated group. Insights into the mechanism underlying such hair growth effects of HAPLN1 will provide a novel potential strategy for treating hair loss with much lower side effects than the current treatments.

• BMB Reports
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• v.57 no.5
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• pp.244-249
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• 2024

Many types of cancer are associated with excessive angiogenesis. Anti-angiogenic treatment is an effective strategy for treating solid cancers. This study aimed to demonstrate the inhibitory effects of (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP) in VEGFA-induced angiogenesis. The results indicated that MMPP effectively suppressed various angiogenic processes, such as cell migration, invasion, tube formation, and sprouting of new vessels in human umbilical vein endothelial cells (HUVECs) and mouse aortic ring. The inhibitory mechanism of MMPP on angiogenesis involves targeting VEGFR2. MMPP showed high binding affinity for the VEGFR2 ATP-binding domain. Additionally, MMPP improved VEGFR2 thermal stability and inhibited VEGFR2 kinase activity, suppressing the downstream VEGFR2/AKT/ERK pathway. MMPP attenuated the activation and nuclear translocation of NF-κB, and it downregulated NF-κB target genes such as VEGFA, VEGFR2, MMP2, and MMP9. Furthermore, conditioned medium from MMPP-treated breast cancer cells effectively inhibited angiogenesis in endothelial cells. These results suggested that MMPP had great promise as a novel VEGFR2 inhibitor with potent anti-angiogenic properties for cancer treatment via VEGFR2/AKT/ERK/NF-κB signaling pathway.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.49-56
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• 2017

In the human airway, mucus exists to protect the respiratory system as a primary barrier of the innate immune system. However, hyperexpressed mucus limits airflow, resulting in a decrease of lung function. Among more than 20 mucin family members, MUC5AC and MUC5B are major glycoproteins in human airway mucus. The epidermal growth factor receptor (EGFR) signaling pathway is one of the mechanisms of these mucins expression and specificity protein-1 (Sp1) transcription factor is the downstream signal of this pathway, playing pivotal roles in mucin expression. Even though there are some drugs for treating mucus hypersecretion, no drug has proven effects on humans. We found that the flavonoid tilianin regulated MUC5AC expression and also inhibited Sp1 phosphorylation. In this study, we investigated how tilianin would modulate EGFR signaling and regulate mucin production. In conclusion, tilianin inhibited MUC5AC expression mediated via modulating the EGFR-MEK-ERK-Sp1 signaling pathway in NCI-H292 human airway epithelial cells. This study may provide the basis for the novel treatment of mucus hypersecretion.

• Biomolecules & Therapeutics
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• v.24 no.4
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• pp.395-401
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• 2016

Endochondral bone formation is the process by which mesenchymal cells condense into chondrocytes, which are ultimately responsible for new bone formation. The processes of chondrogenic differentiation and hypertrophy are critical for bone formation and are therefore highly regulated. The present study was designed to investigate the effect of aloe-emodin on chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Aloe-emodin treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. ATDC5 cells were treated with aloe-emodin and stained with alcian blue. Compared with the control cells, the ATDC5 cells showed more intense alcian blue staining. This finding suggested that aloe-emodin induced the synthesis of matrix proteoglycans and increased the activity of alkaline phosphatase. Aloe-emodin also enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, BSP and RunX2 in a time-dependent manner. Furthermore, examination of the MAPK signaling pathway showed that aloe-emodin increased the activation of extracellular signal-regulated kinase (ERK), but had no effect on p38 and c-jun N-terminal kinase (JNK). Aloe-emodin also enhanced the protein expression of BMP-2 in a time-dependent manner. Thus, these results showed that aloe-emodin exhibited chodromodulating effects via the BMP-2 or ERK signaling pathway. Aloe-emodin may have potential future applications for the treatment of growth disorders.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.56-63
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• 2007

Insulin stimulates the fusion of intracellular vesicles containing glucose transporter 4 (GLUT4) with plasma membrane in adipocytes and muscle cells. Here we show that adipocyte differentiation results in enhanced insulin sensitivity of glucose uptake. On the other hand, glucose uptake in response to platelet-derived growth factor (PDGF) stimulation was markedly reduced by adipocyte differentiation. Expression level of insulin receptor and caveolin-1 was dramatically increased during adipocyte differentiation. Adipocyte differentiation caused :ilightly enhanced activation of acutely transforming retrovirus AKT8 in rodent T cell lymphoma (Akt) by insulin stimulation. However, activation of Akt by PDGF stimulation was largely reduced. Activation of ERK was not detected in both fibroblasts and adipocytes after stimulation with insulin. PDGF-dependent activation of ERK was reduced by adipocyte differentiation. Insulin-dependent glucose uptake was abrogated by LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, in both fibroblasts and adipocytes. Also disassembly of caveolae structure by $methyl-\beta-cyclodextrin$ caused impairment of Akt activation and glucose uptake. Finally, insulin receptor, Akt, SH2-domain-containing inositol 5-phosphatase 2 (SHIP2), and regulatory subunit of PI3K are localized at lipid raft domain and the translocation was facilitated upon insulin stimulation. Given these results, we suggest that lipid raft provide proper site for insulin action for glucose uptake.

• Toxicological Research
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• v.20 no.3
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• pp.233-239
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• 2004

The present study was designed to determine the impact of mercury on endotoxin-induced inflammatory cytokine expression and corresponding signal transduction in mouse kidney. Male BALB/c mice were exposed continuously to 0, 0.3, 1.5, 7.5, or 37.5 ppm of mercury in drink-ing water for 14 days and at the end of the treatment period, lipopolysaccharide (LPS, 0.5 mg/kg) was injected intraperitoneally 2 h prior to euthanasia. The doses of mercury and LPS did not cause hepatotoxicity or renal toxicity as indicated by unaltered plasma alanine aminotransferase and aspartate aminotransferase levels, and terminal UTP nucleotide end-labeling assay from kidney, respectively. Mercury decreased kidney glutathione (GSH) and with LPS, it additively decreased GSH. Mercury activated p38 mitogen-activated protein kinase (MAPK) and additively increased LPS-induced p38 MAPK phosphorylation. In contrast, mercury inhibited LPS-induced activation of extra-cellular signal-regulated kinase (ERK) but had no effect alone. Mercury increased the gene expression of tumor necrosis factor $\alpha$ (TN F$\alpha$) and potentiated LPS-induced TNF$\alpha$ expression. Mercury did not affect LPS-induced interleukin-1$\beta$ (IL-1$\beta$) expression but decreased LPS-induced IL-6 expression. These results suggest that low levels of mercury might augment LPS-induced TNF$\alpha$ expression by altering GSH and p38 MAPK. Mercury modulates LPS-induced p38 and ERK activation, and downstream TNF$\alpha$ and IL-6 expression in kidney, respectively.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.299-305
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• 2012

Endochondral bone formation is the process by which mesenchymal cells condense to become chondrocytes, which ultimately form new bone. The process of chondrogenic differentiation and hypertrophy is critical for bone formation and as such is regulated by many factors. In this study, we aimed to indentify novel factors that regulate chondrogenesis. We investigated the possible role of isopsoralen in induction of chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Isopsoralen treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. Further, ATDC5 cells treated with isopsoralen were stained more intensely with Alcian blue than control cells, suggesting that isopsoralen increases the synthesis of matrix proteoglycans. Similarly, isopsoralen markedly induced the activation of alkaline phosphatase activity compared with control cells. Isopsoralen enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, OCN, Smad4 and Sox9 in a time-dependent manner. Furthermore, isopsoralen induced the activation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase, but not that of c-jun N-terminal kinase (JNK). Isopsoralen significantly enhanced the protein expression of BMP-2 in a time-dependent manner. PD98059 and SB 203580, inhibitors of ERK and p38 MAPK, respectively, decreased the number of stained cells treated with isopsoralen. Taken together, these results suggest that isopsoralen mediates a chondromodulating effect by BMP-2 or MAPK signaling pathways, and is therefore a possible therapeutic agent for bone growth disorders.

• Natural Product Sciences
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• v.22 no.4
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• pp.246-251
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• 2016

This study investigated the effects of (-)-sesamin on memory deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of Parkinson's disease (PD). MPTP lesion (30 mg/kg/day, 5 days) in mice showed memory deficits including habit learning memory and spatial memory. However, treatment with (-)-sesamin (25 and 50 mg/kg) for 21 days ameliorated memory deficits in MPTP-lesioned mouse model of PD: (-)-sesamin at both doses improved decreases in the retention latency time of the passive avoidance test and the levels of dopamine, norepinephrine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid, improved the decreased transfer latency time of the elevated plus-maze test, reduced the increased expression of N-methyl-D-aspartate (NMDA) receptor, and increased the reduced phosphorylation of extracellular signal-regulated kinase (ERK1/2) and cyclic AMP-response element binding protein (CREB). These results suggest that (-)-sesamin has protective effects on both habit learning memory and spatial memory deficits via the dopaminergic neurons and NMDA receptor-ERK1/2-CREB system in MPTP-lesioned mouse model of PD, respectively. Therefore, (-)-sesamin may serve as an adjuvant phytonutrient for memory deficits in PD patients.