• 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.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.448-468
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• 1996

To maintain its functional integrity, bone is continuously remodelled by a process involving resorption by osteoeclasts and formation by osteoblasts, In order to respond to changes in the physical environment or to trauma with the relevant action, this process is strictly regulated by locally synthesized or systemic fators, Prostaglandin $E_2(PGE_2$) is perhaps one of the best studied factors, having been known to affect bone cell function for several decades.$PGE_2$ has both anabolic and catabolic activities. Excess of $PGE_2$ has been implicated in a number of pathological states associated with bone loss in a number of chronic inflammatory conditions such as periodontal disease and rheumatoid arthritis. $PGE_2$ and other arachidonic acid metabolites have been shown to be potent stimulators of osteoclastic bone resorption in organ culture. The anabolic effects of $PGE_2$ were first noticed when an increase in periosteal woven bone formation was seen after the infusion of $PGE_2$ into infants in order to prevent closure of the ductus arteriosus. The cellular basis for the catabolic actions of $PGE_2$ has been well characterized. $PGE_2$increases osteoclast recruitment in bone marrow cell cultures. Also $PGE_2$ has a direct action on osteoclast serving to inhibit activity and can also indirectly activate osteoclast via other cells in the vicinity, presumably osteoblast. The cellular mechanisms for the anabolic actions of $PGE_2$ are not nearly so well understood. The purpose of this paper was to study the effects of $PGE_2$ and dibutyl(DB)cAMP on osteoblastic clone MC3T3El cells and on the generation of osteoclasts from their precursor cells. The effect of $PGE_2$ and DBcAMP on the induction of alkaline phoaphatase(AlP) was investigated in osteoblastic clone MC3T3El cells cultured in medium containing 0.4% fetal bovine serum. $PGE_2$ and DBcAMP stimulated ALP activity and MTT assay in the cells in a dose-dependent manner at concentrations of lO-SOOng/ml. Cycloheximide, protein synthesis inhibitor, inhibited the stimulative effect of $PGE_2$ and DBcAMP on ALP activity in the cells. $PGE_2$also increased the intracellular cAMP content in a dose-dependent fashion with a maximal effect at 500ng/ml. The effect of $PGE_2$ on the generation of osteoclasts was investigated in a coculture system of mouse bone marrow cells with primary osteoblastic cells cultured in media containing 10% fetal bovine serum.After cultures, staining for tartrate-resistant acid phosphatase(TRAP)-marker enzyme of osteoclast was performed. The TRAP(+) multinucleated cells(MNCs), which have 3 or more nuclei, were counted. More TRAP(+) MNCs were formed in coculture system than in control group. $PGE_2(10^{-5}10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in culture. $PGE_2(10^{-6}M)$ stimulated the formation of osteoclast cells from mouse bone marrow cells in coculture of osteoblastic clone MC3T3E1 cells This results suggest that $PGE_2$ stimulates the differentiation of osteoblasts and generation of osteoclast, and are involved in bone formation, as well as in bone resorption.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.592-602
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• 2014

In the Integrated Gasification Combined Cycle (IGCC), the stability of the gasifier has strong influences on the rest of the plant as it supplies the feed to the rest of the power generation system. In order to ensure a safe and stable operation of the entrained-flow gasifier and for protection of the gasifier wall from the high internal temperature, the solid slag layer thickness should be regulated tightly but its control is hampered by the lack of on-line measurement for it. In this study, a previously published dynamic simulation model of a Shell-type gasifier is reproduced and two different linear model predictive control strategies are simulated and compared for multivariable control of the entrained-flow gasifier. The first approach is to control a measured secondary variable as a surrogate to the unmeasured slag thickness. The control results of this approach depended strongly on the unmeasured disturbance type. In other words, the slag thickness could not be controlled tightly for a certain type of unmeasured disturbance. The second approach is to estimate the unmeasured slag thickness through the Kalman filter and to use the estimate to predict and control the slag thickness directly. Using the second approach, the slag thickness could be controlled well regardless of the type of unmeasured disturbances.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.130-136
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• 2004

In the present study, prey preference of juvenile fishes was examined using an experimental approach. Zooplankton composition, as a prey of the fish, was evaluated by taking into account the species as well as body size of juveniles in the aquarium. The predation of juvenile fishes is known to be an important factor in changes of zooplankton communities. In some previous studies at the regulated Nakdong River, the collapse of large cladcoerans and an increase in the rotifer population by selective predation during spring and summer were observed. This study focused on the predation of juvenile fishes such as Hyporhamphus sajori, Rhinogobius brunneus, and Opsariichtys uncirostris amurensis on zooplankton community structure in mesocosm scale experiments. These fishes selected the cladoceran Moina micrura with highest individual preference value (Manly/Chesson index)among zooplankton prey in the experimental aquarium. When the size-selective prey preferences of the juvenile fish were compared, both small (body size <2 cm) and large (body size >2cm) juveniles of O. uncirostris positively selected M. micrura. In the outdoor experimental tanks, juvenile fishes consumed the cladoceran M. micrura, resulting in an high abundance of the rotifer, Polyarthra spp. The results suggest that juvenile fish predation may play an important role in regulating the zooplankton community structure by reducing the cladoceran density and increase of rotifers in the Nakdong River during spring and summer.

• The Journal of Internal Korean Medicine
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• v.33 no.4
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• pp.405-417
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• 2012

Objectives : In the present study, anti-metastatic properties of the methanol extract of L. obtusiloba (MLO) were evaluated. Methods : To determine the effect of MLO on cancer metastasis, we checked matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) activities and expressions in B16F10 melanoma cells. In addition, we performed cell migration assay as well as invasion assay using Matrigel. Finally, we used an in vivo lung metastasis model to confirm the anti-metastatic activity of MLO. Results : 1. MLO showed potent inhibitory effects on MMP-2 and MMP-9 activities and expressions via down-regulation of activation of NF-${\kappa}B$ in B16F10 melanoma cells. 2. Melanoma cell migration and invasion were down-regulated by MLO treatment. 3. Not only in vitro model, but MLO also significantly suppressed lung metastasis in vivo. Conclusions : The present results indicate that MLO has strong inhibitory effect on cancer metastasis. Therefore, L. obtusiloba could be a valuable anti-metastatic agent.

• Tuberculosis and Respiratory Diseases
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• v.73 no.5
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• pp.258-265
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• 2012

Background: Vitamin D can translocate a vitamin D receptor (VDR) from the nucleus to the cell membranes. The meaning of this translocation is not elucidated in terms of a role in pathogenesis of chronic obstructive pulmonary disease (COPD) till now. VDR deficient mice are prone to develop emphysema, suggesting that abnormal function of VDR might influence a generation of COPD. The blood levels of vitamin D have known to be well correlated with that of lung function in patients with COPD, and smoking is the most important risk factor in development of COPD. This study was performed to investigate whether cigarette smoke extracts (CSE) can inhibit the translocation of VDR and whether mitogen activated protein kinases (MAPKs) are involved in this inhibition. Methods: Human alveolar basal epithelial cell line (A549) was used in this study. 1,25-$(OH_2)D_3$ and/or MAPKs inhibitors and antioxidants were pre-incubated before stimulation with 10% CSE, and then nucleus and microsomal proteins were extracted for a Western blot of VDR. Results: Five minutes treatment of 1,25-(OH2)D3 induced translocation of VDR from nucleus to microsomes by a dose-dependent manner. CSE inhibited 1,25-$(OH_2)D_3$-induced translocation of VDR in both concentrations of 10% and 20%. All MAPKs inhibitors did not suppress the inhibitory effects of CSE on the 1,25-$(OH_2)D_3$-induced translocation of VDR. Quercetin suppressed the inhibitory effects of CSE on the 1,25-$(OH_2)D_3$-induced translocation of VDR, but not in n-acetylcysteine. Conclusion: CSE has an ability to inhibit vitamin D-induced VDR translocation, but MAPKs are not involved in this inhibition.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.712-719
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• 1998

Thyroid function is mainly regulated through cAMP and phophatidylinositol, and it is well known that TSH-stimulated thyroxine ($T_4$) release is inhibited by catecholamine from mouse thyroids via the ${\alpha}_1$-adrenoceptor stimulation. Previous study has established that the inhibition of $T_4$ release by ${\alpha}_1$-adrenoceptor stimulation results in activated protein kinase C (PKC). The purpose of this study was to determine if ion transport systems are involved in the inhibition of $T_4$ release elicited by ${\alpha}_1$-adrenergic agonist in mouse thyroids. TSH-, IBMX- and cAMP analogue-stimulated $T_4$ release were significantly inhibited by methoxamine, R59022 (diacylglycerol kinase inhibitor), and MDL (adenylate cyclase inhibitor). TSH-stimulated $T_4$ release could be inhibited by Bay K 8644 and cyclopiazoic acid, but not by verapamil and tetrodotoxin. The addition of nifedipine ($Ca^{2+}$ channel blocker), tetrodotoxin and lidocaine ($Na^+$ channel blockers), but not amiloride (EIPA) and ryanodine, completely blocked the inhibitory effects of methoxamine on $T_4$ release. TSH-stimulated $T_4$ release was also inhibited by benzamil ($Na^+-Ca^{2+}$ exchange inhibitor). TSH-, IBMX- and cAMP-stimulated $T_4$ release were inhibited by methoxamine or R59022, these effects were reversed by nifedipine. but not by verapamil. Furthermore, nifedipine reversed the inhibitory effects of benzamil and R59022 on TSH-stimulated $T_4$ release. These data suggest that the observed ${\alpha}_1$-adrenoceptor-mediated inhibition of $T_4$ release in mouse thyroids is the result of an increase in intracellular $Na^+$ or $Ca^{2+}$ effected via activation of fast $Na^+$ or nifedipine-sensitive $Ca^{2+}$ channels, and that $Na^+-Ca^{2+}$ exchange may play an important role in reducing thyroid hormone by increasing intracellular $Ca^{2+}$.

• The Korea Journal of Herbology
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• v.29 no.6
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• pp.21-26
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• 2014

Objectives : Taraxacum coreanum (TC) have been used as a traditional medicine to treat inflammatory diseases and anti-oxidant effect in Korea. However, the anti-inflammatory effect of TC water extract on lipopolysaccharide (LPS)-induced inflammation is not well-known. Therefore, this study was performed to identify the anti-inflammatory effect of TC on LPS induced inflammatory. Methods : RAW 264.7 cells were treated with 500 ng/mL of LPS. Water extracts of TC (0.1, 0.25, 0.5 mg/ml) was treated 1 h prior to LPS. Cell viability was measured by MTT assay. Levels of nitric oxide (NO) were measured with Griess reagent and pro-inflammatory cytokines were measured by enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (real-time PCR). We also examined molecular mechanisms such as mitogen-activated protein kinases (MAPKs) and nuclear factor-B ($NF-{\kappa}B$) activation by western blot. Results : Water Extract from TC itself did not have any cytotoxic effect in RAW 264.7 cells. TC treatment inhibited the production of NO production, and pro-inflamamtory cytokines such as interleukin (IL)-6 and $IL-1{\beta}$ on protein and mRNA levels. In addition, TC treatment inhibited the LPS-induced activation of MAPKs such as extracellular signal-regulated kinase1/2 (ERK1/2), p38 kinases (p38), c-Jun $NH_2$-terminal kinase (JNK) and $NF-{\kappa}B$. Conclusions : In summary, our result suggest that treatment of TC could reduce the LPS-induced inflammation. Thereby, TC could be used as a protective agent against inflammation. Also, this study could give a clinical basis that TC could be a drug or agent to prevent inflammation.

• Journal of Life Science
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• v.21 no.10
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• pp.1487-1493
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• 2011

E. tarda, a fish pathogen, can survive in seawater under relatively high salt conditions as well as in fish under physiological salt conditions. Bacterial growth under different salt concentrations may influence the expression of genes involved in bacterial structure and physiology. The growth rate of E. tarda culture in high salt (3.5% NaCl) was similar to that in low salt (1.0% NaCl, physiological salt concentration). Interestingly, the strain moved much faster in low salt conditions than in high salt conditions. Electron microscopic observation demonstrated that the bacterial cells grown in high salt had less or no flagellation. Obvious flagellation was observed in the parental strain E. tarda CK41 grown in low-salt condition. Two putative genes coding flagellin were identified in the E. tarda genome sequences. The amino acid sequence comparison of each gene revealed 93% identities. A flagellin gene was PCR amplified and cloned into a cloning vector. Using an E. coli protein expression system, a part of flagellin protein was overexpressed. Using the purified protein, an anti-flagellin antibody was raised in the rabbit. Immunoblot analyses with flagellin specific antibody demonstrated that E. tarda CK41 expressed falgellin in low salt conditions, which is consistent with the results seen in motility assay and microscopic observation. This is the first report of salt regulated flagella expression in E. tarda.

• Journal of Life Science
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• v.21 no.10
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• pp.1385-1392
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• 2011

It is well known that both insulin-like growth factor-I and suppressor of cytokine signaling-3 (SOCS-3) are known to modulate various aspects of physiology in skeletal muscle cells. Furthermore, although SOCS-3 expression is related to insulin resistance in non-skeletal muscle cells and is known to interact with insulin-like growth factor-I receptor, the effect of IGF-I on SOCS-3 gene expression in skeletal muscle cells is presently unknown. C2C12 myotubes were treated with different concentrations (0-200 ng/ml) of IGF-I or for various periods of time (3-72 hr). Immunofluorescent staining image revealed that IGF-I induced SOCS-3 protein expression in a dose-dependent manner. Western blot data also showed that SOCS-3 proteins were induced by IGF-I (200 ng/ml) in C2C12 myotubes in a time-dependent manner. The level of SOCS-3 mRNA was also significantly increased after 3hr of IGF-I (10-100 ng/ml) treatment. However, the levels of SOCS-3 mRNA were significantly decreased after 24 and 48 hr of IGF-I (10-100 ng/ml) treatment compared to the control. In conclusion, SOCS-3 protein is induced by IGF-I treatment in C2C12 skeletal muscle cells and this induction is regulated pretranslationally. The modulating effect of IGF-I on SOCS-3 expression may be an important regulator of gene expression in skeletal muscle cells.