• Biomolecules & Therapeutics
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• 제4권1호
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• pp.103-109
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• 1996

To investigate the effect of the third intracellular loop (i3 loop) peptide of human $\beta$$_2$-adrenergic receptor on receptor agonist binding, we expressed third intracellular loop region of human $\beta$$_2$-adrenergic receptor as glutathione S-transferase fusion protein in E. coli. DNA fragment of the receptor gene which encodes amino acid 221-274 of human $\beta$$_2$-adrenergic receptor was amplified by polymerase chain reaction and subcloned into the bacterial fusion protein expression vector pGEX-CS and expressed as a form of glutathione-S-transferase (GST) fusion protein in E. coli DH5$\alpha$. The receptor fusion protein was identified by SDS-PAGE and Western blot using monoclonal anti-GST antibody. The fusion protein expressed in this study was purified to an apparent homogeneity by glutathione Sepharose CL-4B affinity chromatography. The purified i3 loop fusion proteins at a concentration of 10 $\mu\textrm{g}$/ι caused right shift of the isoproterenol competition curve of [$^3$H]Dihydroalprenolol binding to hamster lung $\beta$$_2$-adrenergic receptor indicating lowered affinity of isoproterenol to $\beta$$_2$-adrenergic receptor possibly due to the uncoupling of receptor and G protein in the presence of the fusion protein. The uncoupling of receptor and G protein suggests that i3 loop region plays a critical role on $\beta$$_2$-adrenergic receptor G protein coupling.

• 한국식품과학회지
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• 제41권2호
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• pp.220-224
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• 2009

선천성 면역 반응을 위해 중요한 역할을 하는 TLRs가 외부 병원성 물질에 자극을 받게 되면 NF-${\kappa}$B를 활성화시키며, 그 결과로 염증을 유도하는 COX와 같은 유전자를 발현한다. 이번 연구에서, 옛날부터 지금까지 전통적인 약재로써 질병 치료에 다양하게 쓰이고 있는 감초의 뿌리에서 추출한 성분 중의 하나인 ILG가 NF-${\kappa}$B활성과 COX 발현을 어떻게 조절하여 항염증 효과를 가지고 있는지 알아보았다. ILG는 TLR agonists인 MALP-2, Poly[I:C], 그리고 LPS에 의해 유도된 NF-${\kappa}$B 활성화와 COX-2 발현을 억제시켰다. 또한 ILG는 리간드(ligand)에 독립적인 TLRs signaling downstream molecules인 MyD88, IKK ${\beta}$, 그리고 p65에 의해서 유도된 NF-${\kappa}$B 활성을 억제시켰다. 이러한 결과는 한약재로서 많이 이용되는 감초가 단지 한약의 쓴맛을 줄이기 위함이 아니라 TLRs 신호전달 체계를 조절하여 항염증 효과를 가지고 있다는 것을 보여주는 것이라 할 수 있겠다.

• The Korean Journal of Physiology and Pharmacology
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• 제14권3호
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• pp.185-189
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• 2010

The present study demonstrates the effect of fibrates, agonists of $PPAR{\alpha}$ on cytokines-induced proliferation in primary cultured astrocytes. Alone or combination treatment with cytokines, such as IL-$1{\beta}$ (10 ng/ml), $IFNP{\gamma}$ (10 ng/ml), and TNF-$\alpha$ (10 ng/ml) cause a significant increase of cell proliferation in a time-dependent manner. Treatment of astrocytes with bezafibrate and fenofibrate (0, 5, and $10\;{\mu}M$) reduced the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation in a dose-dependent manner. To address the involvement of IL-6 on the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation, released IL-6 level was measured. $IFNP{\gamma}$ and IL-$1{\beta}$ cause an increase of released IL-6 protein level in a time-dependent manner. Furthermore, pretreatment with IL-6 antibody (0, 0.1, 1, 2.5, and 5 ng/ml) dose-dependently inhibited the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation. However, bezafibrate and fenofibrate did not affect increased mRNA and protein levels of IL-6 in $IFNP{\gamma}$ and IL-$1{\beta}$-stimulated astrocytes. Taken together, these results clearly suggest that activation of $PPAR{\alpha}$ attenuates the $IFNP{\gamma}$ and IL-$1{\beta}$-induced cell proliferation through IL-6 independent pathway.

• Toxicological Research
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• 제20권3호
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• pp.205-211
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• 2004

Concern that some chemicals in our environment may affect human health by disrupt-ing normal endocrine function has prompted a research on interactions of environmental contaminants with steroid hormone receptor. Toxaphene and chlordane are among the 12 persistent organic pollutants identified by the United Nations Environment Programme as requiring urgent attention. We compared the estrogenic activity of two organochlorine pesticides, toxaphene and chlordane, at estrogen receptor a (ER$\alpha$) and estrogen receptor $\beta$ (ER$\beta$). Human hepatoma cells (HepG2) were transiently transfected with rat ER$\alpha$ or ER$\beta$ plus an estrogen-responsive complement C3-luciferase (C3-Luc) reporter gene. After transfection, cells were treated with various concentrations of toxaphene and chlordane to investigate agonism or antagonism of these chemicals. Both toxaphene and chlordane were potent agonists in HepG2 cells for ER$\alpha$. In contrast, these chemicals had a minimal agonist activity with ER$\beta$ and almost abolished 17$\beta$-estradiol-induced ER$\beta$-mediated activity. Therefore, toxaphene and chlordane behaved as an ER$\alpha$ agonist and an ER$\beta$ antagonist with estrogen-responsive reporter plasmid C3-Luc, and exposure to these organochlorine pesticides could have a crictical effect on normal endocrine function.

• Molecules and Cells
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• 제41권3호
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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.

• Biomolecules & Therapeutics
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• 제4권1호
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• pp.97-102
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• 1996

To investigate whether human $\beta$$_2$-adrenergic receptor devoid of the C-terminal two transmembrane helices retain its ligand binding activity and specificity, 5'780-bp DNA fragment of the receptor gene which encodes amino acid 1-260 of human $\beta$$_2$-adrenergic receptor was subcloned into the bacterial fusion protein expression vector and expressed as a form of glutathione-S-transferase (GST) fusion protein in E. coli DH5$\alpha$. The receptor fusion protein was expressed as a membrane bound form which was verified by SDS-PAGE and Western blot. The fusion protein expressed in this study specifically bound $\beta$-adrenergic receptor ligand [$^3$H] Dihydroalprenolol. In saturation ligand binding assay, the $K_{d}$ value was 7.6 nM which was similar to that of intact $\beta$$_2$-adrenergic receptor in normal animal tissue ( $K_{d}$=1~2 nM) and the $B_{max}$ value was 266 fmol/mg membrane protein. In competition binding assay, the order of binding affinity of various adrenergic receptor agonists to the fusion protein was isoproterenol》epinephrine norepinephrine, which was similar to that of intact receptor in normal animal tissue. These results suggest that N-terminal five transmembrane helices of the $\beta$$_2$-adrenergic receptor be sufficient to determine the ligand binding activity and specificity, irrespective of the presence or absence of the C-terminal two transmembrane helices.s.s.s.

• Biomolecules & Therapeutics
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• 제12권4호
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• pp.215-220
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• 2004

In an attempt to develop new anti-diabetic agents, a series of aryloxypropanolamine derivatives was synthesized to serve as ${\beta}_3$ adrenoceptor agonists. Among these derivatives, 1-{1-methyl-3-[4-(2-methyl-2H-1,2,3,4-tetrazol-5-yl)phenyl]propylamino}-3-phenoxy-2-propanol (KR60886) possessed a high affinity for the ${\beta}_3$ adrenoceptor (Ki = 28 nM) and moderate affinities for ${\beta}_1$ and ${\beta}_2$ adrenoceptors (Ki = 95 nM and 100 nM, respectively). In addition, KR60886 stimulated cAMP production with an EC$_{50}$ of 0.4 ${\mu}M$, confirming its agonistic activity for the ${\beta}_3$ adrenoceptor. In vivo activities of KR60886 were examined by using a fat-fed/streptozotocin (STZ)-treated rat model and the ob/ob mouse model. Oral administration of KR60886 (10 mg/kg) for 3 days (b.i.d.) to fat-fed/STZ-treated rats significantly lowered plasma glucose levels and reduced plasma free fatty acid concentrations. Similarly, KR60886 treatment (10 mg/kg/day for 7 d) resulted in a reduction of plasma glucose concentrations in ob/ob mice. The present study suggests that KR60886 is a potent ${\beta}_3$ receptor agonist with in vivo anti-diabetic properties.

• Clinical and Experimental Emergency Medicine
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• 제3권3호
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• pp.175-180
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• 2016

Objective Combination of ${\beta}_1-adrenergic$ receptor (AR) blockade and ${\beta}_2-AR$ activation might be a potential novel therapy for treating heart failure. However, use of ${\beta}-AR$ agonists and/or antagonists in the clinical setting is controversial because of the lack of information on cardiac inotropic or chronotropic regulation by AR signaling. Methods In this study, we performed hemodynamic evaluation by examining force frequency response (FFR), Frank-Starling relationship, and response to a non-selective ${\beta}-AR$ agonist (isoproterenol) in hearts isolated from 6-month-old transgenic (TG) mice overexpressing ${\beta}_1-$ and ${\beta}_2-ARs$ (${\beta}_1-$ and ${\beta}_2-AR$ TG mice, respectively). Results Cardiac physiologic consequences of ${\beta}_1-$ and ${\beta}_2-AR$ overexpression resulted in similar maximal response to isoproterenol and faster temporary decline of positive inotropic response in ${\beta}_2-AR$ TG mice. ${\beta}_1-AR$ TG mice showed a pronounced negative limb of FFR, whereas ${\beta}_2-AR$ TG mice showed high stimulation frequencies with low contractile depression during FFR. In contrast, Frank-Starling relationship was equally enhanced in both ${\beta}_1-$ and ${\beta}_2-AR$ TG mice. Conclusion Hemodynamic evaluation performed in the present showed a difference in ${\beta}_1-$ and ${\beta}_2-AR$ signaling, which may be due to the difference in the desensitization of ${\beta}_1-$ and ${\beta}_2-ARs$.

• Journal of Nutrition and Health
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• 제34권8호
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• pp.905-911
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• 2001

Phytoestrogens, especially soy-derived isoflavones, are receiving great scrutiny as a food supplement for preventing hormone dependent diseases such as cardiovascular diseases, cancer, and osteoporosis. These beneficial effects of phytoestrogens are caused by functioning as partial agonists or antagonists of estrogens. In contrast to the common usage of soy bean, Yak-kong(Rhynchosia Molubilis ; ) has been used as supplements of estrogen fir preventing postmenopausal osteoporosis in Oriental medicine. To investigate estrogenic effects of Yak-kong and soy bean on the proliferation of MG-63 osteoblastic cells, each bean was extracted with 70% methanol and dried by freeze-drying. Yak-kong treatment of MG-63 cells resulted in an increase of cell proliferation to a maximum of 76% compared to 68% of soy bean treatment. Treatment of MG-63 cells with Yak-kong extract also resulted in an increase of transactivation of an ERE(estrogen response element)-luciferase reporter plasmid and IGF-I expression selectively. Despite increased effects of both bean treatments on the expression of estrogen receptor $\alpha$(ER$\alpha$) and $\beta$(ER$\beta$), soy bean treatment decreased transactivation of an ERE-luciferase reporter plasmid and did not further enhance IGF-I expression. Together, our data demonstrates that the greater estrogenic response of Yak-kong extract for MG-63 cell proliferation is mediated by ER derived transactivation of ERE and selective induction of IGF-I expression.

• Journal of Medicine and Life Science
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• 제16권2호
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• pp.43-45
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• 2019

Intraoperative delivery of salbutamol (${\beta}_2$ agonist) through a breathing circuit may be performed in asthma patient. A 28-year-old woman with a history of asthma was diagnosed with chronic sinusitis and bilateral nasal polyps, and an endoscopic sinus surgery was performed. The patient was recommended salbutamol nebulization every 4 hours during the perioperative period because of the risk of asthma attack. At the end of the operation, when salbutamol was sprayed through the tube before extubation and the connector tip went inside the tube during injection. The patient was immediately referred to the pulmonary medicine department for bronchoscopy, where the foreign body was removed safely without any complications. When general anesthesia is performed on a patient who usually uses an inhaler for asthma, caution is required because the tip that connects the inhaler and the breathing circuit can aspirate into the endotracheal tube and enter the lungs when applying the inhaler before waking up the patient.