• YAKHAK HOEJI
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• v.49 no.2
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• pp.147-150
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• 2005

Macrophage scavenger receptors (MSRs) induce microglial interaction with ${\beta}$-amyloid fibrils (fA${\beta}$) that are associated with Alzheimer's disease (AD). Although microglia are know n to have a dual effect on formation of plaque and clearance of fA${\beta}$ in the AD brain, receptor-mediated phagocytosis is a very important tool for preventing amyloid plaque via activated microglia in the early stage of AD. In the study, we examined whether ginsonoside Rg3 enhances the microglial Phagocytosis of A${\beta}$1-42 through Phagocytosis assay, gene expression (RT-PCR) and protein assay (western blots) for the cell responsiveness presented between Rg3-treated and non-treated groups. Fluro-labeled Ac-LDL and E.coli particles were used as control proteins for phagocytosis. In previous studies, this was a particularly interesting property of Rg3 in the stimulation and phagocytosis of macrophages in the periphery. We report here that ginsenoside Rg3 increased the expression of type-A MSR (MSR-A) in microglia and thus accelerated the phagocytosis with an effective degradation of engulfed fA${\beta}$. This result suggests that Rg3 may play an important role in removing fA${\beta}$ by enhancing the receptor-mediated phagocytosis. In addition, Rg3 could be a potential candidate for balancing the rate of production of fA${\beta}$ in AD brain.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.67-70
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• 1973

This experiment was carried out to investigate the influence of adrenergic receptor blockade. on digitalis intoxication. The effects of adrenergic alpha and beta receptor blockade on the lethal dose of digitonin were evaluated. $LD_{50}$ and dose mortality curve of digitonin in mice pretreated with dibenzylin or propranolol hydrochloride (Inderal) were obtained. All drugs were injected subcutaneously. Digitonin toxicity was significantly decreased in mice pretreated with beta·blockade compare with alpha-blockade and control groups.

• The Journal of the Korean Society for Microbiology
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• v.35 no.5_6
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• pp.363-363
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• 2000

• Nutritional Sciences
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• v.8 no.3
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• pp.159-168
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• 2005

Phytoestrogens, especially Yak-kong or soybean-derived isoflavones have been traditionally used as a supplement of estrogen for preventing postmemopausal osteoporosis in oriental folk medicine. In our previous study, the treatment of Yak-kong and soybean increased estrogen receptor-a (ERa) expression and proliferation of MG-63 osteoblastic cells. In contrast, the increase of estrogen receptor-$\beta$ (ER$\beta$) expression in proliferating MG-63 cells with Yak-kong and soybean treatment was less pronounced, which suggested that ER$\beta$ may play a role rather in the regulation of bone cell differentiation To determine the role of ER$\beta$ in Yak-kong or soybean mediated regulation of bone cell differentiation, we established MG-63 cell lines stably expressing either ER$\beta$ or antisense ER$\beta$ RNAs. Increased expression of ER$\beta$ did not affect ERa expression and proliferation of MG-63 cells. However, increased expression of ER$\beta$ in MG-63 cells (ER$\beta$-MG63 cells) selectively enhanced Yak-kong or soybean induced expression of osteoprotegerin (OPG), a novel soluble glycoprotein which is secreted from osteoblasts and mediates the signal for osteoclast differentiation. Inhibition of ER$\beta$ expression by antisense ER$\beta$ RNAs (As-ER$\beta$-MG63) caused these cells to insensitize Yak-kong or soybean induced expression of OPG but increased MG-63 cell proliferation. Furthermore, the comparable effects between Yak-kong and the combined treatment of genistein and daidzein at $0.5{\times}l0^{-8}$ M, which is a concentration of these two isoflavones similar to Yak-kong at 0.001 mg/mL, on OPG expression in ER$\beta$-MG63 cell demonstrate that the enhanced expression of OPG with Yak-kong treatment is mediated by the synergistic effect of low leveled isoflavones in the extracts. Together, coupled with low level of ER expression in osteoclasts, our data demonstrate that ER$\beta$ in osteoblasts plays an important role in Yak-kong and soybean mediated inhibition of osteoclast differentiation indirectly by enhancing the expression of OPG.

• Reproductive and Developmental Biology
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• v.30 no.4
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• pp.271-277
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• 2006

Transforming growth $factor-{\beta}\;(TGF-{\beta})$ has been shown to have a positive effect on in vitro fertilization (IVF) and has been reported to stimulate meiosis at follicular level in variety of species. The study was designed to determine the expression patterns of $TGF-{\beta}1,\;TGF-{\beta}$ receptors type I, II and Smads gene in bovine oocytes and embryos. $TGF-{\beta}1$ and their receptors were observed in the unfertilized oocytes. $TGF-{\beta}1$ and type II receptor were not expressed at the blastocyst stage, however, only type I receptor was exclusively observed at the same stage. The blastocyst stage, in particular, showed high levels of mRNA expression patterns containing a $TGF-{\beta}1$ type I receptor. The mRNA expression pattern of Smad 2 at all stages of embryonic development was similar in all respect with $TGF-{\beta}1$ type I receptor. On the contrary, Smad 3 and 4 were expressed with high and low level mRNA at the blastocyst stage. In conclusion. it is suggested that $TGF-{\beta}1$ signaling may be regarded as an important entity during the preimplantation embryo development.

• Molecules and Cells
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• v.41 no.10
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• pp.909-916
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• 2018

In pancreatic ${\beta}$ cells, glucose stimulates the biosynthesis of insulin at transcriptional and post-transcriptional levels. The RNA-binding protein, polypyrimidine tract-binding protein 1 (PTBP1), also named hnRNP I, acts as a critical mediator of insulin biosynthesis through binding to the pyrimidine-rich region in the 3'-untranslated region (UTR) of insulin mRNA. However, the underlying mechanism that regulates its expression in ${\beta}$ cells is unclear. Here, we report that glucose induces the expression of PTBP1 via the insulin receptor (IR) signaling pathway in ${\beta}$ cells. PTBP1 is present in ${\beta}$ cells of both mouse and monkey, where its levels are increased by glucose and insulin, but not by insulin-like growth factor 1. PTBP1 levels in immortalized ${\beta}$ cells established from wild-type (${\beta}IRWT$) mice are higher than levels in ${\beta}$ cells established from IR-null (${\beta}IRKO$) mice, and ectopic re-expression of IR-WT in ${\beta}IRKO$ cells restored PTBP1 levels. However, PTBP1 levels were not altered in ${\beta}IRKO$ cells transfected with IR-3YA, in which the Tyr1158/1162/1163 residues are substituted with Ala. Consistently, treatment with glucose or insulin elevated PTBP1 levels in ${\beta}IRWT$ cells, but not in ${\beta}IRKO$ cells. In addition, silencing Akt significantly lowered PTBP1 levels. Thus, our results identify insulin as a pivotal mediator of glucose-induced PTBP1 expression in pancreatic ${\beta}$ cells.

• Journal of Korean Academy of Nursing
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• v.34 no.6
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• pp.1108-1116
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• 2004

Purpose: This research was conducted to provide basic information about the effects of aerobic exercise on physiological change in middle-aged obese women according to differences of ${\beta}$3-adrenergic receptor polymorphisms. Method: Twenty-nine middle aged obese women with over 30%BMI were divided into three groups according to ${\beta}$3-adrenergic receptor gene polymorphism[Variable Group(VG):9, Normal Group(NG):10, Control Group(CG):10]. The VG and NG groups performed walking at 50% exercise intensity for 30 minutes a day, 4 days a week, for 12 weeks. The data was analyzed using the SPSS program. Result: The level of leptin, insulin and % body fat in the VG and NG groups was significantly lower than those of the CG after 12 weeks. In addition, the level of HDL-C in the VG and NG was significantly higher than that of the CG after 12 weeks. However, TC, TG and body weight between groups didn't appear significant at the end of 12 weeks. Conclusions: Aerobic exercise didn't cause differences in persons with differing ${\beta}$3-adrenergic receptor gene polymorphisms, but aerobic exercise affected the physiological change in middle-aged obese women. The findings suggest that aerobic exercise is a desirable nursing intervention for obesity control in middle-aged obese women.

• BMB Reports
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• v.40 no.2
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• pp.180-188
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• 2007

In vivo studies have demonstrated that aldosterone is an independent contributor to glomerulosclerosis. In the present study, we have investigated whether aldosterone itself mediated glomerulosclerosis, as angiotensin II (Ang II) did, by inducing cultured renal mesangial cells to produce plasminogen activator inhibitor-1 (PAI-1), and whether these effects were mediated by aldosterone-induced increase in transforming growth factor $\beta_1$ (TGF-$\beta_1$) expression and cellular reactive oxygen species (ROS) activity. Quiescent rat mesangial cells were treated by aldosterone alone or by combination of aldosterone and spironolactone, Ang II, neutralizing antibody to TGF-$\beta_1$ or antioxidant Nacetylcysteme (NAC). This study indicate that aldosterone can increase PAI-1 mRNA and protein expression by cultured mesangial cells alone, which is independent of aldosterone-induced increases in TGF-$\beta_1$ expression and cellular ROS. The effects on PAI-1, TGF-$\beta_1$ and ROS generation were markedly attenuated by spironolactone, a mineralocorticoid receptor antagonist, which demonstrate that mineralocorticoid receptor (MR) may play a role in mediating these effects of aldosterone.

• Biomolecules & Therapeutics
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• v.25 no.1
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• pp.12-25
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• 2017

G protein-coupled receptors (GPCRs) are a family of cell-surface proteins that play critical roles in regulating a variety of pathophysiological processes and thus are targeted by almost a third of currently available therapeutics. It was originally thought that GPCRs convert extracellular stimuli into intracellular signals through activating G proteins, whereas ${\beta}$-arrestins have important roles in internalization and desensitization of the receptor. Over the past decade, several novel functional aspects of ${\beta}$-arrestins in regulating GPCR signaling have been discovered. These previously unanticipated roles of ${\beta}$-arrestins to act as signal transducers and mediators of G protein-independent signaling have led to the concept of biased agonism. Biased GPCR ligands are able to engage with their target receptors in a manner that preferentially activates only G protein- or ${\beta}$-arrestin-mediated downstream signaling. This offers the potential for next generation drugs with high selectivity to therapeutically relevant GPCR signaling pathways. In this review, we provide a summary of the recent studies highlighting G protein- or ${\beta}$-arrestin-biased GPCR signaling and the effects of biased ligands on disease pathogenesis and regulation.

• Molecules and Cells
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• v.41 no.3
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• pp.234-243
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• 2018

In recent years, the interest towards the relationship between incretins and bone has been increasing. Previous studies have suggested that glucagon-like peptide-1 (GLP-1) and its receptor agonists exert beneficial anabolic influence on skeletal metabolism, such as promoting proliferation and differentiation of osteoblasts via entero-osseous-axis. However, little is known regarding the effects of GLP-1 on osteoblast apoptosis and the underlying mechanisms involved. Thus, in the present study, we investigated the effects of liraglutide, a glucagon-like peptide-1 receptor agonist, on apoptosis of murine MC3T3-E1 osteoblastic cells. We confirmed the presence of GLP-1 receptor (GLP-1R) in MC3T3-E1 cells. Our data demonstrated that liraglutide inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as detected by Annexin V/PI and Hoechst 33258 staining and ELISA assays. Moreover, liraglutide upregulated Bcl-2 expression and downregulated Bax expression and caspase-3 activity at intermediate concentration (100 nM) for maximum effect. Further study suggested that liraglutide stimulated the phosphorylation of AKT and enhanced cAMP level, along with decreased phosphorylation of $GSK3{\beta}$, increased ${\beta}-catenin$ phosphorylation at Ser675 site and upregulated nuclear ${\beta}-catenin$ content and transcriptional activity. Pretreatment of cells with the PI3K inhibitor LY294002, PKA inhibitor H89, and siRNAs GLP-1R, ${\beta}-catenin$ abrogated the liraglutide-induced activation of cAMP, AKT, ${\beta}-catenin$, respectively. In conclusion, these findings illustrate that activation of GLP-1 receptor by liraglutide inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation through $cAMP/PKA/{\beta}-catenin$ and $PI3K/Akt/GSK3{\beta}$ signaling pathways.