• Title/Summary/Keyword: Receptor subtype

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Expression, Purification and NMR Studies on MC4R-TM2 Mutant

  • Oh, Dae-Seok;Yun, Ji-Hye;Lee, Weon-Tae
    • Journal of the Korean Magnetic Resonance Society
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    • v.16 no.1
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    • pp.34-45
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    • 2012
  • Melanocortin-4 receptor (MC4R) subtype is associated with obese humans. Especially, in a patient with severe early-onset obesity, novel heterozygous mutation in the MC4R gene was detected, resulting in an exchange of aspartic acid to asparagine in $90^{th}$ amino acid residue located in the predicted second trans-membrane domain (TM2). Mutations in the melanocortin-4 receptor (MC4R) gene are the most frequent monogenic causes of severe obesity which have been described as heterozygous with loss of function. In order to compare structure difference between MC4R wild type (MC4R-TM2-wt) and mutant (MC4R-TM2-D90N), we designed both MC4R-TM2-wt and MC4R-TM2-D90N construct in pET 21b vector. In this study, we optimized high-yield purification procedure for recombinant TM2-D90N. Eluted recombinant protein was resolubilized under urea condition for thrombin cleavage reaction and we conducted the high-performance liquid chromatography (HPLC) with reverse phase column under 1% acetonitrile, 0.01% TFA buffer solution. The molecular size of purified target peptide was confirmed by Tricine-SDS page analysis. To characterize MC4R-TM2-D90N, we have performed $^{15}N$-isotope labeling of peptide using M9 media and purified labeled target peptide for hetero-nuclear NMR spectroscopy.

The characteristics of adrenergic responses in tilapis dorsal aorta (틸라피아 배대동맥의 아드레날린성 반응의 특성)

  • Choi, Dong-Lim;Chung, Joon-Ki
    • Journal of fish pathology
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    • v.9 no.1
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    • pp.41-51
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    • 1996
  • The present study was undertaken to investigate the physiological characteristics of the adrenergic responses in the tilapia dorsal aorta. Epinephrine, norepinephrine, clonidine and methoxamine in the presence of propranolol($3{\times}10^{-6}$M), induced only endothelium-independent and concentration-dependent vasocontractions in tilapia dorsal aorta. The rank order of potency of adrenergic agonists inducing vasocontraction was epinephrine>norepinephrine>phenylephrine>clonidine>ethoxamine, Yohimbine produced a parallel shift of the concentration-vascontraction curves of epinephrine, norepinephrine, phenylephrine and clonidine to the right, while prazosin depressed the maximum responses of epinephrine and norepinephrine. Calcium-free physiological solution and verapamil markedly reduced epinephrine or norepinephrine-induced vasocontractions. These results suggest that a-adrenergic agonists produce only on endothelium-inedpenent casoconstrictions in tilapia dorsal aorta and these effect of a-adrenergic agonists, which might be associated with both calcium release from intracellular stores and calcium influx through voltage-dependent calcium channel.

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Association of Human Epidermal Growth Factor Receptor-2 Expression and Clinicopathological Findings in Patients with Colorectal Cancer

  • Karaca, Halit;Deniz, Kemal;Berk, Veli;Inanc, Mevlude;Ozkan, Metin
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.12
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    • pp.6221-6225
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    • 2012
  • Background: To determine the frequency of HER-2 overexpression in colorectal cancer (CRC) patients, and to explore the relationship between clinicopathological prognostic factors and their effects on survival, based on immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) analysis. Materials and Methods: The study included 80 patients with a histologically proven diagnosis of CRC that received adjuvant FOLFOX-4 chemotherapy at our department between March 2006 and September 2010. Patient data were analyzed retrospectively. Results: The median follow-up period and age of the patients were 24 months and 59 years, respectively. In immunohistochemical staining, 3+ staining was found in 2 patients (2.5%) while 2+ was in 13 (16%). FISH for HER-2 was performed for all of these 15 patients; samples which were 3+ showed positivity but the ones with 2+ were negative. There was no significant correlation between HER-2 expression and age, gender, tumor localization, histological subtype, grade, lymphovascular and perineural invasion, or pTN stage (P>0.05), even when the patients with HER-2 overexpression were analyzed separately. There was also no significant relationship between progression-free survival (PFS) and overall survival (OS), and HER-2 expression, gender, tumor localization, obstruction-perforation, bleeding, histological type, grade, lymphovascular and perineural invasion, or pT staging (P>0.05); however, there was a significant relationship between lymph node involvement, and PFS and OS (P<0.05). Conclusions: Evaluation of HER-2 overexpression in a more comprehensive, multi-center, prospective trial with standardized methods will be an appropriate approach.

Roles of Metabotropic Glutamate Receptors 1 and 5 in Rat Medial Vestibular Nucleus Neurons

  • Lee, Hae-In;Lee, Sung-Hyo;Chun, Sang-Woo
    • International Journal of Oral Biology
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    • v.36 no.2
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    • pp.71-78
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    • 2011
  • Using whole cell current- and voltage-clamp recording we investigated the characteristics and pharmacology of group I metabotropic glutamate receptor (mGluR)-mediated responses in rat medial vestibular nucleus (MVN) neurons. In current clamp conditions, activation of mGluR I by application of the group I mGluR agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) induced a direct excitation of MVN neurons that is characterized by depolarization and increased spontaneous firing frequency. To identify which of mGluR subtypes are responsible for the various actions of DHPG in MVN, we used two subtype-selective antagonists. (S)-(+)- alpha-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist that is selective for mGluR5. In voltage clamp conditions, DHPG application increased the frequency of spontaneous and miniature inhibitory postsynaptic currents (IPSCs) but had no effect on amplitude distributions. Antagonism of the DHPG-induced increase of miniature IPSCs required the blockade of both mGluR1 and mGluR5. DHPG application induced an inward current, which can be enhanced under depolarized conditions. DHPG-induced current was blocked by LY367385, but not by MPEP. Both LY367385 and MPEP antagonized the DHPG-induced suppression of the calcium activated potassium current ($I_{AHP}$). These data suggest that mGluR1 and mGluR5 have similar roles in the regulation of the excitability of MVN neurons, and show a little distinct. Furthermore, mGluR I, via pre- and postsynaptic actions, have the potential to modulate the functions of the MVN.

Association of Insulin Receptor Substrate-1 G972R Variant with Non-small Cell Lung Cancer Risk

  • Lee, Chang Youl;Ahn, Chul Min;Jeon, Jeong Hee;Kim, Hyung Jung;Kim, Se Kyu;Chang, Joon;Kim, Sung Kyu;Chang, Yoon Soo
    • Tuberculosis and Respiratory Diseases
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    • v.67 no.1
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    • pp.8-13
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    • 2009
  • Background: The insulin receptor substrate-1 (IRS-1) is the primary docking molecule for the insulin-like growth factor I receptor (IGF-IR), and is required for activation of the phosphatidylinositol 3'-kinase (PI3K) pathway. IRS-1 activation of the (PI3K) pathway regulates IGF-mediated survival, enhancement of cellular motility and apoptosis. Therefore, we attempted to ascertain whether IRS-1 genetic variations affect an individual's risk for non-small cell lung cancer (NSCLC). Methods: Two-hundred and eighteen subjects, either diagnosed with NSCLC or control subjects, were matched by age, gender and smoking status. Genomic DNA from each subject was amplified by PCR and analyzed according to the restriction fragment length polymorphism (RFLP) profile to detect the IRS-1 G972R polymorphism. Results: The frequencies of each polymorphic variation, in the control population, were as follows: GG=103 (94.5%) and GR=6 (5.5%); for the NSCLC subjects, the genotypic frequencies were as follows: GG=106 (97.2%) and GR=3 (2.8%). We could not demonstrate statistically significant differences in the genotypic distribution between the NSCLC and the control subjects (p=0.499, Fisher's Exact test). The relative risk of NSCLC, associated with the IRS-1 G972R polymorphic variation, was 1.028 (95% CI; 0.63~9.90). In addition, we found no differences between polymorphic variants with regard to the histological subtype of NSCLC. Conclusion: We did not observe any noteworthy differences in the frequency of the IRS-1 G972R polymorphism in NSCLC patients, compared to control subjects. These results suggest suggesting that, in our study population, the IRS-1 G972R polymorphism does may not appear to be associated with an increased risk of NSCLC.

Effects of a gintonin-enriched fraction on hair growth: an in vitro and in vivo study

  • Lee, Na-Eun;Park, Sang-Deuk;Hwang, Hongik;Choi, Sun-Hye;Lee, Ra Mi;Nam, Sung Min;Choi, Jong Hee;Rhim, Hyewhon;Cho, Ik-Hyun;Kim, Hyoung-Chun;Hwang, Sung-Hee;Nah, Seung-Yeol
    • Journal of Ginseng Research
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    • v.44 no.1
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    • pp.168-177
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    • 2020
  • Background: Ginseng has been widely used as a health-promoting tonic. Gintonin present in ginseng acts as a lysophosphatidic acid (LPA) receptor ligand that activates six LPA receptor subtypes. The LPA6 subtype plays a key role in normal hair growth, and mutations in the LPA6 receptor impair normal human hair growth. Currently, human hair loss and alopecia are concerning issues that affect peoples' social and day-to-day lives. Objective: We investigated the in vitro and in vivo effects of a gintonin-enriched fraction (GEF) on mouse hair growth. Methods: Human hair follicle dermal papilla cells (HFDPCs) and six-week-old male C57BL/6 mice were used. The mice were divided into the four groups: control, 1% minoxidil, 0.75% GEF, and 1.5% GEF. The dorsal hair was removed to synchronize the telogen phase. Each group was treated topically, once a day, for 15 days. We analyzed hair growth activity and histological changes. Results: GEF induced transient [Ca2+]i, which stimulated HFDPC proliferation and caused 5-bromo-2'-deoxyuridine (BrdU) incorporation in a concentration-dependent manner. GEF-mediated HFDPC proliferation was blocked by the LPA receptor antagonist and Ca2+ chelator. HFDPC treatment with GEF stimulated vascular endothelial growth factor release. Topical application of GEF and minoxidil promoted hair growth in a dose-dependent manner. Histological analysis showed that GEF and minoxidil increased the number of hair follicles and hair weight. Conclusion: Topical application of GEF promotes mouse hair growth through HFDPC proliferation. GEF could be one of the main components of ginseng that promote hair growth and could be used to treat human alopecia.

Predicting Successful Conservative Surgery after Neoadjuvant Chemotherapy in Hormone Receptor-Positive, HER2-Negative Breast Cancer

  • Ko, Chang Seok;Kim, Kyu Min;Lee, Jong Won;Lee, Han Shin;Lee, Sae Byul;Sohn, Guiyun;Kim, Jisun;Kim, Hee Jeong;Chung, Il Yong;Ko, Beom Seok;Son, Byung Ho;Ahn, Seung Do;Kim, Sung-Bae;Kim, Hak Hee;Ahn, Sei Hyun
    • Journal of Breast Disease
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    • v.6 no.2
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    • pp.52-59
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    • 2018
  • Purpose: This study aimed to determine whether clinicopathological factors are potentially associated with successful breast-conserving surgery (BCS) after neoadjuvant chemotherapy (NAC) and develop a nomogram for predicting successful BCS candidates, focusing on those who are diagnosed with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative tumors during the pre-NAC period. Methods: The training cohort included 239 patients with an HR-positive, HER2-negative tumor (${\geq}3cm$), and all of these patients had received NAC. Patients were excluded if they met any of the following criteria: diffuse, suspicious, malignant microcalcification (extent >4 cm); multicentric or multifocal breast cancer; inflammatory breast cancer; distant metastases at the time of diagnosis; excisional biopsy prior to NAC; and bilateral breast cancer. Multivariate logistic regression analysis was conducted to evaluate the possible predictors of BCS eligibility after NAC, and the regression model was used to develop the predicting nomogram. This nomogram was built using the training cohort (n=239) and was later validated with an independent validation cohort (n=123). Results: Small tumor size (p<0.001) at initial diagnosis, long distance from the nipple (p=0.002), high body mass index (p=0.001), and weak positivity for progesterone receptor (p=0.037) were found to be four independent predictors of an increased probability of BCS after NAC; further, these variables were used as covariates in developing the nomogram. For the training and validation cohorts, the areas under the receiver operating characteristic curve were 0.833 and 0.786, respectively; these values demonstrate the potential predictive power of this nomogram. Conclusion: This study established a new nomogram to predict successful BCS in patients with HR-positive, HER2-negative breast cancer. Given that chemotherapy is an option with unreliable outcomes for this subtype, this nomogram may be used to select patients for NAC followed by successful BCS.

Cytokine-cytokine receptor interactions in the highly pathogenic avian influenza H5N1 virus-infected lungs of genetically disparate Ri chicken lines

  • Vu, Thi Hao;Hong, Yeojin;Truong, Anh Duc;Lee, Jiae;Lee, Sooyeon;Song, Ki-Duk;Cha, Jihye;Dang, Hoang Vu;Tran, Ha Thi Thanh;Lillehoj, Hyun S.;Hong, Yeong Ho
    • Animal Bioscience
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    • v.35 no.3
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    • pp.367-376
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    • 2022
  • Objective: The highly pathogenic avian influenza virus (HPAIV) is a threat to the poultry industry as well as the economy and remains a potential source of pandemic infection in humans. Antiviral genes are considered a potential factor for HPAIV resistance. Therefore, in this study, we investigated gene expression related to cytokine-cytokine receptor interactions by comparing resistant and susceptible Ri chicken lines for avian influenza virus infection. Methods: Ri chickens of resistant (Mx/A; BF2/B21) and susceptible (Mx/G; BF2/B13) lines were selected by genotyping the Mx dynamin like GTPase (Mx) and major histocompatibility complex class I antigen BF2 genes. These chickens were then infected with influenza A virus subtype H5N1, and their lung tissues were collected for RNA sequencing. Results: In total, 972 differentially expressed genes (DEGs) were observed between resistant and susceptible Ri chickens, according to the gene ontology and Kyoto encyclopedia of genes and genomes pathways. In particular, DEGs associated with cytokine-cytokine receptor interactions were most abundant. The expression levels of cytokines (interleukin-1β [IL-1β], IL-6, IL-8, and IL-18), chemokines (C-C Motif chemokine ligand 4 [CCL4] and CCL17), interferons (IFN-γ), and IFN-stimulated genes (Mx1, CCL19, 2'-5'-oligoadenylate synthase-like, and protein kinase R) were higher in H5N1-resistant chickens than in H5N1-susceptible chickens. Conclusion: Resistant chickens show stronger immune responses and antiviral activity (cytokines, chemokines, and IFN-stimulated genes) than those of susceptible chickens against HPAIV infection.

Effects Of Site-mutagenesis of $^{123}Arginine$ residue in $M_1$ Muscarinic Receptor on the Signal Transduction System ($M_1$ Muscarine성 수용체에서 $^{123}Arginine$ 잔기의 Site-mutagenesis가 신호전달계에 미치는 영향)

  • 이석용
    • YAKHAK HOEJI
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    • v.44 no.1
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    • pp.52-59
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    • 2000
  • An exceptionally conserved sequence that is shared among most G protein-coupled neurotransmitter receptors is an aspartate-arginine-tyrosine triplet that is located at the second cytoplasmic domain. Using the ml subtype of muscarinic acetylcholine receptors as an example, a point mutation of the arginine residue at position 123 into asparagine was induced. This mutation resulted in a complete blockade of the carbachol-induced increases of PI hydrolysis and intracellular $Ca^2$$^{+}$ level, in spite of the expression of the wild-type and mutant receptors at similar concentrations in Chinese hamster ovary cells. In marked contrast, the muscarinic agonist carbachol induced concentration-dependent enhancement of the activity of NO synthase at mutant ml receptors although the enhancement was significantly smaller than at wild-type ml receptors. These data suggest that this highly conserved arginine residue plays an important role in coupling of muscarinic receptors to the second messenger systems and the presence of alternate mechanisms of activation of neuronal NO synthase which might be operative in the absence of large changes in the concentration of cellular $Ca^{2+}$.2+/.

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Ligand Binding Properties of Muscarinic Acetylcholine Receptors in Caenorhabditis elegans

  • You, Suck-Jong;Choi, Jung-Do;Cho, Nam-Jeong
    • BMB Reports
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    • v.29 no.6
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    • pp.525-529
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    • 1996
  • Ligand binding properties of muscarinic acetylcholine receptors (mAChRs) in the nematode Caenorhabditis elegans (C. elegans) were characterized by using filtration binding assays. Scatchard analysis using $[^{3}H]N-methylscopolamine$ ($[^{3}H]NMS$) showed that the dissociation constant ($K_d$) and the maximum binding value ($B_{max}$) were $3.3{\pm}0.8{\times}10^{10}$ M and $9.0{\pm}1.1$ fmol/mg protein, respectively. Binding competition experiments indicated that the affinities of C. elegans mAChRs to atropine, scopolamine, and oxotremorine were similar to those of mammalian mAChRs. Pirenzepine binding experiments revealed that the binding pattern of mAChRs in C. elegans closely resembled that of mAChRs in rat brain, suggesting that the receptors consist primarily of Ml subtype. The affinity of mAChRs for oxotrernorine was significantly affected by guanylylimidodiphosphate (Gpp(NH)p), a non hydrolyzable GTP analog, suggesting that mAChRs in C. elegans might be coupled to G proteins. The data presented here indicate the possibility that C. elegans provides a living animal model to study the action mode of the muscarinic cholinergic system.

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