• Korean Journal of Microbiology
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• v.47 no.1
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• pp.7-13
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• 2011

In general, expression of membrane protein in Escherichia coli is very toxic to the host organism, but the mechanism for the toxicity is not clear yet. Expression of human purinergic receptor $P2X_4$ was found to be extremely toxic to the host E. coli. We examined this toxicity by isolation and analysis of less toxic mutant proteins. We could isolate 30 less toxic mutants of $P2X_4$ after hydroxylamine mutagenesis. Western blot showed that all of them produced proteins smaller than the wild type $P2X_4$. DNA sequencing of two largest mutant proteins showed that they were lost its second transmembrane domain. Localization analysis of these mutant proteins showed that they are not in cytoplasmic membrane, but in inclusion bodies. These data showed that inactive truncated $P2X_4$ is not toxic to E. coli and membrane integration and functionality of $P2X_4$ may be needed to show host toxicity.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.1
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• pp.69-79
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• 2021

Objective: Poor ovarian response (POR) refers to a subnormal follicular response that leads to a decrease in the quality and quantity of the eggs retrieved after ovarian stimulation during assisted reproductive treatment (ART). The present study investigated the associations of multiple variants of the estrogen receptor 2 (ESR2) and follicle-stimulating hormone receptor (FSHR) genes with POR in infertile Jordanian women undergoing ART. Methods: Four polymorphisms, namely ESR2 rs1256049, ESR2 rs4986938, FSHR rs6165, and FSHR rs6166, were investigated in 60 infertile Jordanian women undergoing ART (the case group) and 60 age-matched fertile women (the control group), with a mean age of 33.60±6.34 years. Single-nucleotide polymorphisms (SNPs) were detected by restriction fragment length polymorphism and then validated using Sanger sequencing. Results: The p-value of the difference between the case and control groups regarding FSHR rs6166 was very close to 0.05 (p=0.054). However, no significant differences were observed between the two groups in terms of the other three SNPs, namely ESR2 rs1256049, ESR2 rs4986938, and FSHR rs6165 (p=0.561, p=0.433, and p=0.696, respectively). Conclusion: The association between FSHR rs6166 and POR was not statistically meaningful in the present study, but the near-significant result of this experiment suggests that statistical significance might be found in a future study with a larger number of patients.

• KSBB Journal
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• v.28 no.1
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• pp.7-12
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• 2013

Thromboxane $A_2$ ($TXA_2$) is one of major proinflammatory mediators, plays an important role in the development of vascular inflammatory diseases. $TXA_2$ acting through the thromboxane receptor regulates multiple pathways and genes in a variety of cells. In this study, we report that the activation of thromboxane receptor with U46619 increases the interleukin-8 (IL-8) mRNA in vascular endothelial cells. We also demonstrated that U46619 produces the activations of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK), which is required for endothelial IL-8 production. And U46619 enhanced mRNA stability of IL-8 transcripts in endothelial cells. Moreover, inhibition of ERK1/2 or p38MAPK reduced monocyte adhesion to aortic endothelium stimulated by U46619. Therefore, these results suggest that activation of thromboxane receptor promotes the expression of IL-8 via ERK1/2 and p38MAPK activation in endothelial cells.

• YAKHAK HOEJI
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• v.32 no.2
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• pp.101-111
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• 1988

$[^3H]$ Quinuclidinyl benzilate(QNB) binding assays were performed in the dog ventricular sarcolemma fraction enriched approx. 32-fold in sarcolemma compared to the starting homogenate to elucidate the effect of antihistaminics on cardiac muscarinic receptor. Chlorpheniramine(CHP) inhibited specific binding of $[^3H]$QNB and delayed the equilibrium binding. The rate constants at $37^{\circ}C$ for formation and dissociation of the QNB receptor complex were $0.38{\times}10^9\;M^{-1}$ and $1.6{\times}10^{-2}\;min^{-1}$, respectively. The mean value for the dissociation constant from the pairs of the rate constants was 43. 2 pM and this value was similar to the value(44.8pM) determined from Scatchard analysis. CHP decreased association rate constant, indicating increase in $K_D$ value. Decrease in affinity without affecting the binding site concentration$(B_{max})$ for $[^3H]$QNB binding by CHP was also demonstrated by Scatchard analysis. $K_i$ values for $H_i$-blockers that inhibited specific $[^3H]$QNB binding were $0.02{\sim}4.8{\mu}M$. Cimetidine with $K_i$ value of $230{\mu}M$, however, was ineffective in displacing $[^3H]$QNB binding at concentration of $50{\mu}M$. The Hill coefficient for $H_1$-blockers were about one. The results indicate that $H_1$-antihistaminics inhibit $[^3H]$ QNB binding by interaction with myocardiac muscarinic cholinergic receptor and anticholinergic side effects of these drugs are mainly due to this receptor blocking mechanism.

• Tuberculosis and Respiratory Diseases
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• v.74 no.6
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• pp.264-268
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• 2013

Background: Idiopathic pulmonary fibrosis (IPF) is a lethal pulmonary fibrotic disease. In general, the exaggerated activation of the coagulation cascade has been observed during initiation or maintenance of the fibrotic disease. In our recent study, immunohistochemical expression of protease-activated receptor-2 (PAR-2), which plays a key role in coagulation cascade, was observed in surgical specimen of IPF patients, and associated with poor clinical outcome. The aim of this study was to evaluate the overexpression of PAR-2 in inflammatory cells from peripheral blood and bronchoalveolar lavage fluid in IPF patients. Methods: From May 2011 to March 2012, IPF patients and controls were enrolled in Seoul National University Hospital. Peripheral blood and bronchoalveolar lavage fluid were collected for analysis of PAR-2 expression. Flow cytometry and reverse transcription polymerase chain reaction were used for PAR-2 receptor and mRNA assessment. Results: Twelve IPF patients and 14 controls were included in this study. Among them, flow cytometry analysis was conducted from 26 peripheral blood (patient group, 11; control group, 13) and 7 bronchoalveolar lavage fluid (patient group, 5; control group, 2). The expression of PAR-2 receptor was not different between patient and control groups (p=0.074). Among all 24 population, PAR-2 mRNA assessment was performed in 19 persons (patient group, 10; control group, 9). The mRNA expression of PAR-2 was not significant different (p=0.633). Conclusion: In IPF patients, PAR-2 receptor and mRNA expression were not different from control group.

• Molecules and Cells
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• v.39 no.4
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• pp.322-329
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• 2016

Voltage-gated $Ca^{2+}$ ($Ca_V$) channels are dynamically modulated by Gprotein-coupled receptors (GPCR). The $M_1$ muscarinic receptor stimulation is known to enhance $Ca_V2.3$ channel gating through the activation of protein kinase C (PKC). Here, we found that $M_1$ receptors also inhibit $Ca_V2.3$ currents when the channels are fully activated by PKC. In whole-cell configuration, the application of phorbol 12-myristate 13-acetate (PMA), a PKC activator, potentiated $Ca_V2.3$ currents by ~two-fold. After the PMA-induced potentiation, stimulation of $M_1$ receptors decreased the $Ca_V2.3$ currents by $52{\pm}8%$. We examined whether the depletion of phosphatidylinositol 4,5-bisphosphate ($PI(4,5)P_2$) is responsible for the muscarinic suppression of $Ca_V2.3$ currents by using two methods: the Danio rerio voltage-sensing phosphatase (Dr-VSP) system and the rapamycin-induced translocatable pseudojanin (PJ) system. First, dephosphorylation of $PI(4,5)P_2$ to phosphatidylinositol 4-phosphate (PI(4)P) by Dr-VSP significantly suppressed $Ca_V2.3$ currents, by $53{\pm}3%$. Next, dephosphorylation of both PI(4)P and $PI(4,5)P_2$ to PI by PJ translocation further decreased the current by up to $66{\pm}3%$. The results suggest that $Ca_V2.3$ currents are modulated by the $M_1$ receptor in a dual mode-that is, potentiation through the activation of PKC and suppression by the depletion of membrane $PI(4,5)P_2$. Our results also suggest that there is rapid turnover between PI(4)P and $PI(4,5)P_2$ in the plasma membrane.

• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.247-254
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• 2015

In this presentation, I describe the expression and purification of the recombinant liver X receptor β-ligand binding domain proteins in E. coli using a commercially available double cistronic vector, pACYCDuet-1, to express the receptor heterodimer in a single cell as the soluble form. I describe here the expression and characterization of a biologically active heterodimer composed of the liver X receptor β-ligand binding domain and retinoid X receptor α-ligand binding domain. Although many of these proteins were previously seen to be produced in E. coli as insoluble aggregates or "inclusion bodies", I show here that as a form of heterodimer they can be made in soluble forms that are biologically active. This suggests that co-expression of the liver X receptor β-ligand binding domain with its binding partner improves the solubility of the complex and probably assists in their correct folding, thereby functioning as a type of molecular chaperone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.123-128
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• 2016

The study was conducted to confirm the analgesic effects of the Carbenoxolone(CBX)and P2X receptor antagonist(iso-PPADS), which separates the gap junction in the facial neuropathic pain model. The experiment used white male Sprague-Dawley rats (240~280g). The second left molars on the lower jaw was extracted to induce facial neuropathic pain, and small dental implants were implanted to induce damage to the inferior alveolar nerve. When CBX was injected twice daily to the abdominal cavity, a significant analgesic effect at 5ug/kg was observed(p<0.05). In addition, when iso-PPADS was injected twice daily into the abdominal cavity, a significant analgesic reaction was observed at $25{\mu}g/kg$(p<0.05). When the two drugs were injected together at a low concentration, in which they did not display an effect, they displayed a significant analgesic reaction at CBX 1ug/kg and iso-PPADS 2.5ug/kg(p<0.05). When a gap injunction block using a low concentration of CBX and a low concentration P2X receptor antagonist was injected together, the pain suppressing effect was observed against the orofacial neuropathic pain mechanism. These results make it possible to determine that the gap junction block using CBX and the injection of the P2X receptor antagonist plays an important role in the pain management of the facial region.

• BMB Reports
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• v.34 no.6
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• pp.573-577
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• 2001

The mammalian heart is known to undergo significant mechanical changes during fetal and neonatal development. The objective of this study was to define the ontogeny of the ryanodine receptor/$Ca^{2+}$ release channel and SERCA that play the major roles in excitation-contraction coupling. Whole ventricular homogenates of fetal (F) (19 and 22 days in gestation), postnatal (N) (1 and 7 days postnatal), and adult (A) (5 weeks postnatal) Sprague-Dawley rat hearts were used to study [$^3H$]ryanodine binding and oxalate-supported $^{45}Ca^{2+}$ uptake. For the ryanodine receptor, the major findings were: (1) The ryanodine receptor density, as determined by maximal [$^3H$]ryanodine binding ($B_{max}$), increased 3 fold between the F22 and A periods ($0.26{\pm}0.1$ vs. $0.73{\pm}0.07$ pmoles/mg protein, p<0.01), whereas there was no significant change during the F22 and N1 development phases ($0.26{\pm}0.1$ vs. $0.34{\pm}0.01$). (2) Affinity of the ryanodine receptor to ryanodine did not significantly change, as suggested by the lack of change in the $K_d$ during the development and maturation. For SERCA, changes started early with an increased rate of $Ca^{2+}$ uptake in the fetal periods (F19: $8.1{\pm}1.1$ vs. F22: $19.3{\pm}2.2$ nmoles/g protein/min; p<0.05) and peaked by 7 days (N7) of the postnatal age ($34.9{\pm}2.1$). Thus, we conclude that the quantitative changes occur in the ryanodine receptor during myocardial development. Also, the maturation of the $Ca^{2+}$ uptake appears to start earlier than that of the $Ca^{2+}$ release.

• BMB Reports
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• v.38 no.2
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• pp.238-242
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• 2005

5-HT2A is one of major serotonin receptor that is involved in the action of serotonin-targeting drugs. Previous clinical studies have shown an unexpected association between lower cholesterol level and psychiatric diseases, in which T102C polymorphism of HTR2A, gene of 5-HT2A serotonin receptor, might be involved. Therefore, we hypothesized a potential association between lower cholesterol level and T102C polymorphism. The effect of the T102C polymorphism on the serum lipid profiles of 646 subjects without specific psychiatric disease was investigated. Genotype was determined by polymerase chain reaction and restriction fragment length polymorphism analysis. There were significantly lower levels of total cholesterol ($193.6{\pm}35.0$ versus $202.1{\pm}45.5\;mg/dl$, p = 0.016) and HDL-cholesterol ($42.7{\pm}11.6$ versus $46.3{\pm}12.7\;mg/dl$, p = 0.004) in CC genotype than non-CC genotypes. Moreover, multivariate analysis showed that the CC genotype is a strong predictor of a lower HDL-cholesterol level (p < 0.001). In conclusion, this study shows that the CC genotype of the HTR2A gene is related to lower HDL-cholesterol level in Koreans. This is the first demonstration showing the potential genetic relationship between the serotonin receptor gene polymorphism and the HDL-cholesterol level.