• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.77-83
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• 2006

A gene encoding a $\gamma-butyrolactone$ autoregulator receptor was cloned from Saccharopolyspora erythraea, and the biochemical characteristics, including the autoregulator specificity, were determined with the purified recombinant protein. Using primers designed for the conserved amino acid sequence of Streptomyces $\gamma-butyrolactone$ autoregulator receptors, a 120 bp S. erythraea DNA fragment was obtained by PCR. Southern and colony hybridization with the 120 bp fragment as a probe allowed to select a genomic clone of S. erythraea, pESG, harboring a 3.2 kb SacI fragment. Nucleotide sequencing analysis revealed a 615 bp open reading frame (ORF), showing moderate homology (identity, $31-34\%$; similarity, $45-47\%$) with the $\gamma-butyrolactone$ autoregulator receptors from Streptomyces sp., and this ORF was named seaR (Saccharopolyspora erythraea autoregulator receptor). The seaR/pET-3d plasmid was constructed to overexpress the recombinant SeaR protein (rSeaR) in Escherichia coli, and the rSeaR protein was purified to homogeneity by DEAE-Sephacel column chromatography, followed by DEAE-ion-exchange HPLC. The molecular mass of the purified rSeaR protein was 52 kDa by HPLC gel-filtration chromatography and 27 kDa by SDS-polyacrylamide gel electrophoresis, indicating that the rSeaR protein is present as a dimer. A binding assay with tritium-labeled autoregulators revealed that rSeaR has clear binding activity with a VB-C-type autoregulator as the most effective ligand, demonstrating for the first time that the erythromycin producer S. erythraea possesses a gene for the $\gamma-butyrolactone$autoregulator receptor.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.135-140
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• 2003

Bacillus sp. secretes high levels of extracellular enzymes into the culture medium. The signal recognition particle (SRP) and the SRP receptor play a central role in targeting pre secretory proteins to the translocase. By the analysis of the DNA microarray of B. lentimorbus WJ5, it was detected that WJ5m12, antifungal activity deficient mutant induced by gamma radiation, had a down-regulated expression of the SRP receptor gene (B. subtitis srb homologue, srbL). To determine the relationship of SRP receptor to antifungal activity, srbL of B. lentimorbus WJ5 was amplified by PCR and ligated into pQE30 vector, and then transferred into WJ5m12. The transformant, WJ5m12::srbL, recovered the antifungal activity. From the 2-DE analysis, the several presecretory proteins accumulated in the mutant cell and decreased to a level of the wild type in WJ5m12::srbL. It seems that the srbL could play an important role in the secretion of the antifungal activity related proteins of B. lentimorbus WJ5.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.367-372
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• 2015

Background: Human adiponectin (ApN), a 30 kDa glycoprotein of 244-amino acids which is predominantly produced by adipocytes, exerts its effects via two receptors, namely adiponectin receptor-1 (adipo-R1) and adiponectin receptor-2 (adipo-R2) with differential binding affinity to globular adiponectin. Adiponectin receptor expression has been studied in several cancer tissues. However, there are no studies of colorectal adenomas which are considered to be precursors for colorectal carcinoma (CRC). Objectives: In the present study, the expression of adipo-R1 and adipo-R2 was investigated immunohistochemically in colorectal adenomas and colorectal carcinoma tissues in an attempt to determine associations with these tumors. Materials and Methods: The study enrolled 50 CRC patients with tumor resection and 82 patients who were diagnosed with adenomatous polyps, classified as negative for neoplasia, low-grade dysplasia (L-GD) or high- grade dysplasia (H-GD). Results: Expression of both adipo-R1 and adipo-R2 was found to be significantly lower in the CRCs than in colorectal adenomas (tubular and tubulovillous, p=0.009 and p<0.001, respectively). Adipo-R1 and adipo-R2 expression was also significantly lower in the CRC group when compared with the groups of patients with low grade dysplasia, high-grade dysplasia or no neoplasia (p=0.012 and p<0.001, respectively). In addition, it was observed that adipo-R2 expression was generally positive in the non-neoplastic group irrespective of the adipo-R2 expression. In the L-GD, H-GD and CRC groups, the adipo-R2 result was positive whenever adipo-R1 result was positive but some patients with negative adipo-R1 had positive adipo-R2 (p<0.001, p=0.004, p<0.001, respectively). Conclusions: This study indicated that ApN may play a role in the progression of colorectal adenomatous polyps to carcinoma through actions on adipo-R1 and adipo-R2 receptors.

• Molecules and Cells
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• v.40 no.4
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• pp.254-261
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• 2017

Glioblastomas (GBM) are very difficult to treat and their aggressiveness is one of the main reasons for this as well as for the frequent recurrences. MicroRNAs post-transcriptionally regulate their target genes through interaction between their seed sequence and 3'UTR of the target mRNAs. We previously reported that miR-296-3p is regulated by neurofibromatosis 2 (NF2) and enhances the invasiveness of GBM cells via SOCS2/STAT3. In this study, we investigated whether miR-296-5p, which originates from the same precursor miRNA as miR-296-3p, can increase the invasiveness of GBM cells. It was observed that miR-296-5p potentiated the invasion of various GBM cells including LN229, T98G, and U87MG. Through bioinformatics approaches, two genes were identified as miR-296-5p targets: caspase-8 (CASP8) and nerve growth factor receptor (NGFR). From results obtained from Ago2 immunoprecipitation and luciferase assays, we found that miR-296-5p downregulates CASP8 and NGFR through direct interaction between seed sequence of the miRNA and 3'UTR of the target mRNA. Knockdown of CASP8 or NGFR also increased the invasive ability of GBM cells, indicating that CASP8 and NGFR are involved in potentiation of invasiveness by miR-296-5p. Consistent with our findings, CASP8 was downregulated in brain metastatic lung cancer cells, which have a high level of miR-296-5p, compared to parental cells, suggesting that miR-296-5p may be generally associated with the acquisition of invasiveness. Collectively, our results implicate miR-296-5p as a potential cause of invasiveness in cancer and suggest it as a promising therapeutic target for GBM.

• The Korean Journal of Pain
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• v.14 no.2
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• pp.150-155
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• 2001

Background: Tramadol is known to be a weak opioid. However, it has also been shown that tramadol is an effective norepinephrine and serotonin uptake blocker, which may be effective in the treatment of neuropathic pain. The present study was undertaken in order to assess the antinociceptive action of tramadol and to investigate possible antinociceptive mechanisms by using antagonists in an animal neuropathic pain models in rats. Methods: Rats were prepared with tight ligation at the left 5 and 6th lumbar spinal nerves (Kim and Chung's neuropathic pain model). The antinociceptive effects of tramadol (10, 20, and 50 mg/kg i.p.) in rats with neuropathic pain were assessed. Additionally, following coadministration of antagonists such as naloxone (1 mg/kg i.p.), yohimbine (1 mg/kg i.p.) and ritanserin (1 mg/kg i.p.) with 50 mg/kg of tramadol, the responses to mechanical and thermal stimuli were measured over a two-hour period. Results: Tramadol displayed potent antinociceptive effects in a dose-dependent manner on rats with neuropathic pain (P < 0.05). The effects of tramadol were inhibited by coadministered naloxone and yohimbine in rats with mechanical and thermal allodynia, respectively (P < 0.05). However, there were no significant changes in the pain behaviors in the case of ritanserin. Conclusions: Tramadol showed significant antinociceptive effects in rats with regards to neuropathic pain against both mechanical and thermal allodynia. The antinociceptive effect on the mechanical stimuli is medicated via an opioid receptor. However, it appears that the antinociceptive effects on thermal allodynia are mediated via a noradrenalin receptor vice a serotonergic receptor.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.471-477
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• 2000

In the rabbit renal artery, acetylcholine $(ACh,\;1\;nM{\sim}10\;{\mu}M)$ induced endothelium-dependent relaxation of arterial rings precontracted with norepinephrine $(NE,\;1\;{\mu}M)$ in a dose-dependent manner. $N^G-nitro- L-arginine$ (L-NAME, 0.1 mM), an inhibitor of NO synthase, or ODQ $(1\;{\mu}M),$ a soluble guanylate cyclase inhibitor, partially inhibited the ACh-induced endothelium-dependent relaxation. The ACh-induced relaxation was abolished in the presence of 25 mM KCl and L-NAME. The cytochrome P450 inhibitors, 7- ethoxyresorufin $(7-ER,\;10\;{\mu}M),$ miconazole $(10\;{\mu}M),$ or 17-octadecynoic acid $(17-ODYA,\;10\;{\mu}M),$ failed to inhibit the ACh-induced relaxation in the presence of L-NAME. 11,12-epoxyeicosatrienoic acid $(11,12-EET,\;10\;{\mu}M)$ had no relaxant effect. The ACh-induced relaxation observed in the presence of L-NAME was significantly reduced by a combination of iberiotoxin $(0.3\;{\mu}M)$ and apamin $(1\;{\mu}M),$ and almost completely blocked by 4-aminopyridine (5 mM). The ACh-induced relaxation was antagonized by $P_{2Y}$ receptor antagonist, cibacron blue $(10\;and\;100\;{\mu}M),$ in a dose-dependent manner. Furthermore, 2-methylthio-ATP (2MeSATP), a potent $P_{2Y}$ agonist, induced the endothelium-dependent relaxation, and this relaxation was markedly reduced by either the combination of iberiotoxin and apamin or by cibacron blue. In conclusion, in renal arteries isolated from rabbit, ACh produced non-NO relaxation that is mediated by an EDHF. The results also suggest that ACh may activate the release of ATP from endothelial cells, which in turn activates $P_{2Y}$ receptor on the endothelial cells. Activation of endothelial $P_{2Y}$ receptors induces a release of EDHF resulting in a vasorelaxation via a mechanism that involves activation of both the voltage-gated $K^+$ channels and the $Ca^{2+}-activated\;K^+\;channels$. The results further suggest that EDHF does not appear to be a cytochrome P450 metabolite.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.1661-1675
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• 2016

Objectives: Can addition of neurokinin-1 receptor antagonists (NK1-RAs) be considered as an ideal strategy for the prevention of chemotherapy-induced nausea and vomiting (CINV)? Researchers differ on this question. Materials and Methods: Electronic databases were searched for randomized control trials (RCTs) that evaluated the effectiveness and safety of NK1-RAs in preventing CINV. The primary end point was complete response (CR) in the acute, delayed, and overall phases after chemotherapy. Subgroup analyses evaluated the types of NK1-RAs, routines of administration, types of malignancies, regimens used in combination with NK1-RAs, and age of patients included in the studies. The incidences of different types of adverse events were also extracted to estimate the safety of NK1-RAs. Results: A total of 38 RCTs involving 13,923 patients were identified. The CR rate of patients receiving NK-RAs was significantly higher than patients in the control groups during overall phase (70.8% vs 56.0%, P<0.001), acute phase (85.1% vs 79.6%, P<0.001), and delayed phase (71.4% vs 58.2%, P<0.001). There were three studies including patients of children or adolescents, the CR rate was also significantly higher in the treatment group (overall phase: OR=2.807, P<0.001; acute phase: OR=2.863, P =0.012; delayed phase: OR=2.417, P<0.001). For all the other outcomes, patients in the NK1-RAs groups showed improvements compared to the control groups (incidence of nausea: 45.2% vs 45.9%, P<0.001; occurrence of vomiting: 22.6% vs 38.9%, P<0.001; usage of rescue drugs: 23.5% vs 34.1%, P<0.001). The pooled side effects from NK1-RAs did not significantly differ from previous reports and the toxicity rates in patients less than eighteen years old also did not diff between the two groups (P=0.497). However, we found that constipation and insomnia were more common in the patients of control groups, whereas diarrhea and hiccups were more frequently detected in patients receiving NK1-RAs. Conclusions: NK1-RAs improved the CR rate of CINV. They are effective for both adults and children. The use of NK1-RAs might be associated with the appearance of diarrhea and hiccups, while decreasing the possibility of constipation and insomnia.

• Archives of Pharmacal Research
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• v.28 no.3
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• pp.249-268
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• 2005

Drug metabolizing enzymes (DMEs) play central roles in the metabolism, elimination and detoxification of xenobiotics and drugs introduced into the human body. Most of the tissues and organs in our body are well equipped with diverse and various DMEs including phase I, phase II metabolizing enzymes and phase III transporters, which are present in abundance either at the basal unstimulated level, and/or are inducible at elevated level after exposure to xenobiotics. Recently, many important advances have been made in the mechanisms that regulate the expression of these drug metabolism genes. Various nuclear receptors including the aryl hydrocarbon receptor (AhR), orphan nuclear receptors, and nuclear factor-erythoroid 2 p45-related factor 2 (Nrf2) have been shown to be the key mediators of drug-induced changes in phase I, phase II metabolizing enzymes as well as phase III transporters involved in efflux mechanisms. For instance, the expression of CYP1 genes can be induced by AhR, which dimerizes with the AhR nuclear translocator (Arnt) , in response to many polycyclic aromatic hydrocarbon (PAHs). Similarly, the steroid family of orphan nuclear receptors, the constitutive androstane receptor (CAR) and pregnane X receptor (PXR), both heterodimerize with the ret-inoid X receptor (RXR), are shown to transcriptionally activate the promoters of CYP2B and CYP3A gene expression by xenobiotics such as phenobarbital-like compounds (CAR) and dexamethasone and rifampin-type of agents (PXR). The peroxisome proliferator activated receptor (PPAR), which is one of the first characterized members of the nuclear hormone receptor, also dimerizes with RXR and has been shown to be activated by lipid lowering agent fib rate-type of compounds leading to transcriptional activation of the promoters on CYP4A gene. CYP7A was recognized as the first target gene of the liver X receptor (LXR), in which the elimination of cholesterol depends on CYP7A. Farnesoid X receptor (FXR) was identified as a bile acid receptor, and its activation results in the inhibition of hepatic acid biosynthesis and increased transport of bile acids from intestinal lumen to the liver, and CYP7A is one of its target genes. The transcriptional activation by these receptors upon binding to the promoters located at the 5-flanking region of these GYP genes generally leads to the induction of their mRNA gene expression. The physiological and the pharmacological implications of common partner of RXR for CAR, PXR, PPAR, LXR and FXR receptors largely remain unknown and are under intense investigations. For the phase II DMEs, phase II gene inducers such as the phenolic compounds butylated hydroxyanisol (BHA), tert-butylhydroquinone (tBHQ), green tea polyphenol (GTP), (-)-epigallocatechin-3-gallate (EGCG) and the isothiocyanates (PEITC, sul­foraphane) generally appear to be electrophiles. They generally possess electrophilic-medi­ated stress response, resulting in the activation of bZIP transcription factors Nrf2 which dimerizes with Mafs and binds to the antioxidant/electrophile response element (ARE/EpRE) promoter, which is located in many phase II DMEs as well as many cellular defensive enzymes such as heme oxygenase-1 (HO-1), with the subsequent induction of the expression of these genes. Phase III transporters, for example, P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs), and organic anion transporting polypeptide 2 (OATP2) are expressed in many tissues such as the liver, intestine, kidney, and brain, and play crucial roles in drug absorption, distribution, and excretion. The orphan nuclear receptors PXR and GAR have been shown to be involved in the regulation of these transporters. Along with phase I and phase II enzyme induction, pretreatment with several kinds of inducers has been shown to alter the expression of phase III transporters, and alter the excretion of xenobiotics, which implies that phase III transporters may also be similarly regulated in a coordinated fashion, and provides an important mean to protect the body from xenobiotics insults. It appears that in general, exposure to phase I, phase II and phase III gene inducers may trigger cellular 'stress' response leading to the increase in their gene expression, which ultimately enhance the elimination and clearance of these xenobiotics and/or other 'cellular stresses' including harmful reactive intermediates such as reactive oxygen species (ROS), so that the body will remove the 'stress' expeditiously. Consequently, this homeostatic response of the body plays a central role in the protection of the body against 'environmental' insults such as those elicited by exposure to xenobiotics.

• Biomolecules & Therapeutics
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• v.8 no.4
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• pp.338-348
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• 2000

The present study was attempted to determine the effect of 5'-(N'-ethylcarboxamido) adenosine (NECA), which is an potent $A_2$-adenosine receptor agonist, on catecholamine (CA) secretion evoked by cholinergic stimulation, membrane depolarization and calcium mobilization from the isolated perfused rat adrenal gland. NECA (20 nM) perfused into the adrenal vein for 60 min produced a time-related inhibition in CA secretion evoked by ACh (5.32x10$^{-3}$ M), high $K^{+}$(5.6x10$^{-2}$ M), DMPP (10$^{-4}$ M for 2 min), McN-A-343 (10$^{-4}$ M for 2 min), cyclopiazonic acid (10$^{-5}$ M for 4 min) and Bay-K-8644 (10$^{-5}$ M for 4 min). Also, in the presence of $\beta$,${\gamma}$-methylene adenosine-5'-triphosphate (MATP), which is also known to be a selective $P_{2x}$-purinergic receptor agonist, showed a similar inhibition elf CA release evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid. However, in adrenal glands preloaded with 20$\mu$M NECA for 20 min under the presence of 20$\mu$M 3-isobutyl-1-methyl-xanthine (IBMX), an adenosine receptors antagonist, CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were much recovered in comparison to the case of NECA-treatment only. Taken together, these results indicate that NECA causes the marked inhibition of CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization. This inhibitory effect may be mediated by inhibiting influx of extracellular calcium and release in intracellular calcium in the rat adrenomedullary chromaffin cells through the adenosine receptor stimulation. Therefore, it is suggested that the inhibitory mechanism of adenosine receptor stimulation may play a modulatory role in regulating CA secretion.n.n.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.447-456
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• 1994

In order to elucidate the characterization of receptors involved in inestinal motility of Israeli carp, spontaneously contracting Israeli carp intestinal preperations were prepared and mounted in the organ chambers for contraction traicings using a polygraph. Various contractile agonists were treated and their dose-response curves were constructed. $EC_{50}$ values$(pD_2)$ of each agonist on specific receptors, $pA_2$ values of competitive antagonists against some agonists, and $K_1$, values of noncompetitive antagonists against some agonists were analyzed for characterization of receptors related with the intestinal contraction. Results obtained through the experiments were summarized as follows: 1. Acetylcholine(ACh) exhibited biphasic dose-response curves: initial ACh-induced dose dependent contractions were observed in pM levels but followed by decreased response in in-between concentration levels. Dose dependent contractions reappeared in ${\mu}M$ level. The peaks in pM and ${\mu}M$ levels appeared in $10^{-13}M$ and $3{\times}10^{-5}M$, respectvely. 2. Carbachol(CaCh) exhibited dose dependent contractions from $10^{-9}M$ to $10^{-5}M$, and its $pD_2$ values were higher than those of ACh($5.60{\pm}0.11$). ACh and CaCh exhibited equiactive contractions. Nicotine had no effects on contractile responses of Israeli carp intestine. 3. ACh-induced responses were inhibited by atropine($K_1:7{\times}10^{-8}M$), a muscarinic antagonist, in a non-competitive manner. But CaCh-induced responses were inhibited by both antimuscarinic atropine($pA_2:9.52{\pm}0.14$) and selective $M_2$ antagonistic 4-DAMP($pA_2:8.16{\pm}0.09$), in competitive manners. Nicotine receptor antagonistic decamethonium and hexamethonium had no effects on ACh-and CaCh-induced contractions. Therefore, the cholinergic receptor related to intestinal motility of Israeli carp was assumed as $M_2$ type. 4. In Israeli carp intestine, 5-HT (serotonin) exhibited dose dependent contractions in concentration range from $10^{-8}M$ to $10^{-5}M$. The maximal responses, however, were corresponded to about 50% of those of ACh or CaCh. 5-HT induced contractions were inhibited by $5-HT_2$ antagonistic ketanserin ($K_1: 7.8{\times}10^{-4}M$) in a non-competitive manner, but not by both of anti $5-HT_1$, spiperone and anti $5-HT_3$, MDL-72222. Hence, $5-HT_2$ receptors are suggested to be existed in Isreli carp intestine.