• Molecules and Cells
• /
• v.27 no.3
• /
• pp.351-357
• /
• 2009

Phytoestrogens are the natural compounds isolated from plants, which are structurally similar to animal estrogen, $17{\beta}$-estradiol. Tectoridin, a major isoflavone isolated from the rhizome of Belamcanda chinensis. Tectoridin is known as a phytoestrogen, however, the molecular mechanisms underlying its estrogenic effect are remained unclear. In this study we investigated the estrogenic signaling triggered by tectoridin as compared to a famous phytoestrogen, genistein in MCF-7 human breast cancer cells. Tectoridin scarcely binds to ER ${\alpha}$ as compared to $17{\beta}$-estradiol and genistein. Despite poor binding to ER ${\alpha}$, tectoridin induced potent estrogenic effects, namely recovery of the population of cells in the S-phase after serum starvation, transactivation of the estrogen response element, and induction of MCF-7 cell proliferation. The tectoridin-induced estrogenic effect was severely abrogated by treatment with U0126, a specific MEK1/2 inhibitor. Tectoridin promoted phosphorylation of ERK1/2, but did not affect phosphorylation of ER ${\alpha}$ at $Ser^{118}$. It also increased cellular accumulation of cAMP, a hallmark of GPR30-mediated estrogen signaling. These data imply that tectoridin exerts its estrogenic effect mainly via the GPR30 and ERK-mediated rapid nongenomic estrogen signaling pathway. This property of tectoridin sets it aside from genistein where it exerts the estrogenic effects via both an ER-dependent genomic pathway and a GPR30-dependent nongenomic pathway.

• Biomolecules & Therapeutics
• /
• v.24 no.6
• /
• pp.581-588
• /
• 2016

Lonchocarpine is a phenylpropanoid compound isolated from Abrus precatorius that has anti-bacterial, anti-inflammatory, antiproliferative, and antiepileptic activities. In the present study, we investigated the antioxidant effects of lonchocarpine in brain glial cells and analyzed its molecular mechanisms. We found that lonchocarpine suppressed reactive oxygen species (ROS) production and cell death in hydrogen peroxide-treated primary astrocytes. In addition, lonchocarpine increased the expression of anti-oxidant enzymes, such as heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), and manganese superoxide dismutase (MnSOD), which are all under the control of Nrf2/antioxidant response element (ARE) signaling. Further, mechanistic studies showed that lonchocarpine increases the nuclear translocation and DNA binding of Nrf2 to ARE as well as ARE-mediated transcriptional activities. Moreover, lonchocarpine increased the phosphorylation of AMP-activated protein kinase (AMPK) and three types of mitogen-activated protein kinases (MAPKs). By treating astrocytes with each signaling pathway-specific inhibitor, AMPK, c-jun N-terminal protein kinase (JNK), and p38 MAPK were identified to be involved in lonchocarpine-induced HO-1 expression and ARE-mediated transcriptional activities. Therefore, lonchocarpine may be a potential therapeutic agent for neurode-generative diseases that are associated with oxidative stress.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.28 no.1
• /
• pp.41-52
• /
• 2015

Objective : This study investigated the inhibitory mechanism of the hypopigmentating effects on ethanol extract of Rosae rugosae Flos (ERR) that has not yet been examined. Methods : We analyzed the anti-melanogenic effects of ethanol extracts from Rosae rugosae Flos by tyrosinase activity, melanin contents. We also examined protein expression levels of tyrosinase, TRP-1, TRP-2, MITF and ERK by western blot analysis in melanoma cells. Results : In this investigation, ERR effectively reduced ${\alpha}$-MSH-stimulated melanin synthesis by suppressing expression of tyrosinase and tyrosinase-related protein-1 (TRP-1). On the other hand, the expression of tyrosinase-related protein-2 (TRP-2) were not affected by treatment with ERR. ERR inhibited the expression of microphthalmia-associated transcription factor (MITF) as a key transcription factor for tyrosinase expression regulating melanogenesis. The upstream signaling pathway including cAMP response element-binding protein (CREB) and MAPKs were also inhibited by ERR. Pretreatment with PD98059, ERK inhibitor, attenuated the inhibitory effect of ERR on ${\alpha}$-MSH-induced tyrosinase activity. Conclusions : Our study suggested that the anti-melanogenic activity of ERR is correlated with the suppression of tyrosinase gene through CREB/MITF/ERK pathway.

• Journal of Pharmacopuncture
• /
• v.21 no.1
• /
• pp.35-40
• /
• 2018

Objective: The role of BDNF (brain-derived neurotrophic factor), CREB (cAMP response element binding) and VGF neuropeptide has been proved in antidepressant activity of long term saffron administration in the rat hippocampus. In this study we evaluated the role of these proteins in antidepressant activity of saffron in long term administration in the rat cerebellum. Methods: Saffron aqueous extract (40 and 80 mg/kg/day) and imipramine (10 mg/kg/day) were administered intraperitoneally for 21 days to rats. At the end of experiment, animals were sacrificed and cerebellums were separated. The protein levels of BDNF, VGF, CREB and P- CREB in the rat cerebellum were evaluated using western blot analysis. Results: Saffron aqueous extract (80mg/kg/day) caused significant increase in protein level of P-CREB in long term treatment in the rat cerebellum. The increases in the protein levels of VGF, CREB and BDNF were not significant. Conclusion: In summary, our results showed that antidepressant effect of saffron in rat cerebellum might be due to the enhanced phosphorylation of CREB.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.25 no.3
• /
• pp.635-648
• /
• 1998

The clinical use of fluoride with a well known osteogenic action in osteoporotic patients is rational, because this condition is characterized by impaired bone formation. However, its anabolic effect has not been demonstrated well in vitro. The purpose of this study was to investigate the effects of sodium fluoride on the physiological role of osteoblastic cell. Osteoblastic cells were isolated from fetal rat calvaria. The results were as follows : 1. Mineralized nodules were shown in osteoblastic cell cultures, which had been maintained in the presence of ascorbic acid and ${\beta}-glycerophosphate$ up to 21 days. When cultures were treated with pulses of 48 hr duration before apparent mineralization was occurring, 2-fold increased in their number was detected. 2. Alkaline phosphatase activity of osteoblastic cells was inhibited by sodium fluoride in dose dependent manner. 3. The effect of sodium fluoride on the osteoblastic cell proliferation was measured by the incorporation of $[^3H]$-thymidine into DNA. As a result, sodium fluoride at $1{\sim}100{\mu}M$ increased the $[^3H]$-thymidine incorporation into DNA in a dose dependent manner. 4. The signaling mechanism activated by sodium fluoride dose-dependently enhanced the tyrosine phosphorylation of the adaptor molecule $Shc^{p66}$ and their association with Grb2, one of earlier events in a MAP kinase activation pathway cascade used by a significant subset of G protein-coupled receptors. 5. The phosphorylation of CREB(cAMP response element binding protein)was inhibited by the sodium fluoride in MC3T3E1 cells. In conclusion, the results of this study suggested that the mitogenic effect of the sodium fluoride in MC3T3E1 cell was stimulated in a dose-dependent manner and suggested "an important role for the interaction between She and Grb2" in controlling the proliferation of osteoblasts.

• Herbal Formula Science
• /
• v.27 no.2
• /
• pp.121-136
• /
• 2019

Objective : To investigate the effect of sihogayonggolmoryeotang (SY) on Single Prolonged Stress(SPS)-induced Post Traumatic Stress Disorder(PTSD). Method : To confirm the effects of SY on SPS-induced PTSD, Changes in body weight, sucrose intake open field test(OFT) and forced swimming test(FST)were observed. After behavioral tests, the plasma corticosterone(CORT) from the abdominal aorta, serotonin(5-HT) from prefrontal cortex, hippocampus, amygdala and striatum, norepinephrine(NE) and dopamine(DA) from hippocampus was measured by ELISA. mRNA expression of brain-derived neurotrophic factor(BDNF) and cAMP response element-binding protein(CREB) in hippocampus was measured by RT-PCR. Result : Weight change and sucrose intakes of rats in 14th day after the administration of SY were significantly increased in the SPS + SY450 group compared to the SPS group (p<0.05). Numbers of crossing in the central zone in the OFT were significantly increased in the SPS + SY450 group (p<0.05) compared with the SPS group. The immobility time of FST was significantly decreased in SPS + SY450 group compared with SPS group (p<0.05). The change of plasma CORT concentration was significantly decreased in SPS + SY450 group compared with that in SPS group (p<0.05). The change of 5-HT concentration was significantly increased in the SPS + SY450 group at hippocampus and amygdala compared with the SPS group (p<0.05). The concentration of DA was significantly increased in the SPS + SY450 group compared with the SPS group (p<0.05). The expression of BDNF and CREB were significantly increased in SPS + SY450 group compared with the SPS group (p<0.05). Conclusion : SY administration lowered the increase of CORT caused by PTSD and increases the 5-HT concentration and reversed the decreased expression of NE and DA and BDNF and CREB by PTSD. It is postulated that SY is effective in treating PTSD by restoring cognitive function, memory impairment, unstable emotional disturbances.

• Nutrition Research and Practice
• /
• v.13 no.3
• /
• pp.205-213
• /
• 2019

BACKGROUND/OBJECTIVES: Myocardial infarction (MI) is caused by extensive myocardial damage attributed to the occlusion of coronary arteries. Our previous study in a rat model of ischemia/reperfusion (I/R) demonstrated that administration of arabinoxylan (AX), comprising arabinose and xylose, protects against myocardial injury. In this study, we undertook to investigate whether psyllium seed husk (PSH), a safe dietary fiber containing a high level of AX (> 50%), also imparts protection against myocardial injury in the same rat model. MATERIALS/METHODS: Rats were fed diets supplemented with PSH (1, 10, or 100 mg/kg/d) for 3 d. The rats were then subjected to 30 min ischemia through ligation of the left anterior descending coronary artery, followed by 3 h reperfusion through release of the ligation. The hearts were harvested and cut into four slices. To assess infarct size (IS), an index representing heart damage, the slices were stained with 2,3,5-triphenyltetrazolium chloride (TTC). To elucidate underlying mechanisms, Western blotting was performed for the slices. RESULTS: Supplementation with 10 or 100 mg/kg/d of PSH significantly reduces the IS. PSH supplementation (100 mg/kg/d) tends to reduce caspase-3 generation and increase BCL-2/BAX ratio. PSH supplementation also upregulates the expression of nuclear factor erythroid 2-related factor 2 (NRF2), and its target genes including antioxidant enzymes such as glutathione S-transferase mu 2 (GSTM2) and superoxide dismutase 2 (SOD2). PSH supplementation upregulates some sirtuins ($NAD^+$-dependent deacetylases) including SIRT5 (a mitochondrial sirtuin) and SIRT6 and SIRT7 (nuclear sirtuins). Finally, PSH supplementation upregulates the expression of protein kinase A (PKA), and increases phosphorylated cAMP response element-binding protein (CREB) (pCREB), a target protein of PKA. CONCLUSIONS: The results from this study indicate that PSH consumption reduces myocardial I/R injury in rats by inhibiting the apoptotic cascades through modulation of gene expression of several genes located upstream of apoptosis. Therefore, we believe that PSH can be developed as a functional food that would be beneficial in the prevention of MI.

• Molecules and Cells
• /
• v.42 no.4
• /
• pp.301-312
• /
• 2019

Post-transcriptional regulation underlies the circadian control of gene expression and animal behaviors. However, the role of mRNA surveillance via the nonsense-mediated mRNA decay (NMD) pathway in circadian rhythms remains elusive. Here, we report that Drosophila NMD pathway acts in a subset of circadian pacemaker neurons to maintain robust 24 h rhythms of free-running locomotor activity. RNA interference-mediated depletion of key NMD factors in timeless-expressing clock cells decreased the amplitude of circadian locomotor behaviors. Transgenic manipulation of the NMD pathway in clock neurons expressing a neuropeptide PIGMENT-DISPERSING FACTOR (PDF) was sufficient to dampen or lengthen free-running locomotor rhythms. Confocal imaging of a transgenic NMD reporter revealed that arrhythmic Clock mutants exhibited stronger NMD activity in PDF-expressing neurons than wild-type. We further found that hypomorphic mutations in Suppressor with morphogenetic effect on genitalia 5 (Smg5) or Smg6 impaired circadian behaviors. These NMD mutants normally developed PDF-expressing clock neurons and displayed daily oscillations in the transcript levels of core clock genes. By contrast, the loss of Smg5 or Smg6 function affected the relative transcript levels of cAMP response element-binding protein B (CrebB) in an isoform-specific manner. Moreover, the overexpression of a transcriptional repressor form of CrebB rescued free-running locomotor rhythms in Smg5-depleted flies. These data demonstrate that CrebB is a rate-limiting substrate of the genetic NMD pathway important for the behavioral output of circadian clocks in Drosophila.

• Biomolecules & Therapeutics
• /
• v.31 no.3
• /
• pp.285-297
• /
• 2023

Alzheimer's disease (AD) is a neurodegenerative disease with progressive memory loss and the cognitive decline. AD is mainly caused by abnormal accumulation of misfolded amyloid β (Aβ), which leads to neurodegeneration via a number of possible mechanisms such as down-regulation of brain-derived neurotrophic factor-tropomyosin-related kinase B (BDNF-TRKB) signaling pathway. 7,8-Dihydroxyflavone (7,8-DHF), a TRKB agonist, has demonstrated potential to enhance BDNF-TRKB pathway in various neurodegenerative diseases. To expand the capacity of flavones as TRKB agonists, two natural flavones quercetin and apigenin, were evaluated. With tryptophan fluorescence quenching assay, we illustrated the direct interaction between quercetin/apigenin and TRKB extracellular domain. Employing Aβ folding reporter SH-SY5Y cells, we showed that quercetin and apigenin reduced Aβ-aggregation, oxidative stress, caspase-1 and acetylcholinesterase activities, as well as improved the neurite outgrowth. Treatments with quercetin and apigenin increased TRKB Tyr516 and Tyr817 and downstream cAMP-response-element binding protein (CREB) Ser133 to activate transcription of BDNF and BCL2 apoptosis regulator (BCL2), as well as reduced the expression of pro-apoptotic BCL2 associated X protein (BAX). Knockdown of TRKB counteracted the improvement of neurite outgrowth by quercetin and apigenin. Our results demonstrate that quercetin and apigenin are to work likely as a direct agonist on TRKB for their neuroprotective action, strengthening the therapeutic potential of quercetin and apigenin in treating AD.

• Journal of Life Science
• /
• v.28 no.1
• /
• pp.37-42
• /
• 2018

Non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) is a transforming growth factor beta (TGF-${\beta}$) superfamily gene associated with pro-apoptotic and anti-tumorigenic activities. In the present study, we investigated if caffeic acid phenethyl ester (CAPE) derived from propolis could induce the expression of anti-tumorigenic gene NAG-1. Our results indicate that CAPE significantly induced NAG-1 expression in a time- and concentration-dependent manner in HCT116 cells. We also found that CAPE induced NAG-1 expression in a concentration-dependent manner in another human colorectal cancer cell line, LOVO. In addition, CAPE triggered apoptosis, which was detected with Western blot analysis using poly-(ADP-ribose) polymerase antibody. NAG-1 induction by CAPE was not dependent on transcription factor p53, which was confirmed with Western blot analysis using p53 null HCT116 cells. The luciferase assay results indicated that the new cis-elements candidates were located between -474 and -1,086 of the NAG-1 gene promoter. CAPE dramatically induced activating transcription factor 3 (ATF3) expression, but not cAMP response element-binding protein (CREB), which shares the same binding sites with ATF3. The co-transfection experiment with pCG-ATF3 and pCREB showed that only ATF3 was associated with NAG-1 up-regulation by CAPE, whereas CREB had no effect. In conclusion, the results suggest that CAPE could induce the expression of anti-tumorigenic gene NAG-1 mainly through ATF3.