Association study between OCTN1 functional haplotypes and Crohn's disease in a Korean population

Jung, Eun Suk,Park, Hyo Jin,Kong, Kyoung Ae,Choi, Ji Ha,Cheon, Jae Hee The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.1

Crohn's disease (CD) is a chronic inflammatory bowel disease with multifactorial causes including environmental and genetic factors. Several studies have demonstrated that the organic cation/carnitine transporter 1 (OCTN1) non-synonymous variant L503F is associated with susceptibility to CD. However, it was reported that L503F is absent in Asian populations. Previously, we identified and functionally characterized genetic variants of the OCTN1 promoter region in Koreans. In that study, four variants demonstrated significant changes in promoter activity. In the present study, we determined whether four functional variants of the OCTN1 promoter play a role in the susceptibility to or clinical course of CD in Koreans. To examine it, the frequencies of the four variants of the OCTN1 promoter were determined by genotyping using DNA samples from 194 patients with CD and 287 healthy controls. Then, associations between genetic variants and the susceptibility to CD or clinical course of CD were evaluated. We found that susceptibility to CD was not associated with OCTN1 functional promoter variants or haplotypes showing altered promoter activities in in vitro assays. However, OCTN1 functional promoter haplotypes showing decreased promoter activities were significantly associated with a penetrating behavior in CD patients (HR=2.428, p=0.009). Our results suggest that the OCTN1 functional promoter haplotypes can influence the CD phenotype, although these might not be associated with susceptibility to this disease.

Identification and Functional Characterization of Novel Genetic Variations in the OCTN1 Promoter

Park, Hyo Jin,Choi, Ji Ha The Korean Society of Pharmacology 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.2

Human organic cation/carnitine transporter 1 (OCTN1) plays an important role in the transport of drugs and endogenous substances. It is known that a missense variant of OCTN1 is significantly associated with Crohn's disease susceptibility. This study was performed to identify genetic variants of the OCTN1 promoter in Korean individuals and to determine their functional effects. First, the promoter region of OCTN1 was directly sequenced using genomic DNA samples from 48 healthy Koreans. OCTN1 promoter activity was then measured using a luciferase reporter assay in HCT-116 cells. Seven variants of the OCTN1 promoter were identified, two of which were novel. There were also four major OCTN1 promoter haplotypes. Three haplotypes (H1, H3, and H4) showed decreased transcriptional activity, which was reduced by 22.9%, 23.0%, and 44.6%, respectively (p<0.001), compared with the reference haplotype (H2). Transcription factor binding site analyses and gel shift assays revealed that NF-Y could bind to the region containing g.-1875T>A, a variant present in H3, and that the binding affinity of NF-Y was higher for the g.-1875T allele than for the g.-1875A allele. NF-Y could also repress OCTN1 transcription. These data suggest that three OCTN1 promoter haplotypes could regulate OCTN1 transcription. To our knowledge, this is the first study to identify functional variants of the OCTN1 promoter.

Two Types of Voltage-activated Calcium Currents in Goldfish Horizontal Cells

Paik, Sun-Sook,Bai, Sun-Ho,Jung, Chang-Sub The Korean Society of Pharmacology 2005 The Korean Journal of Physiology & Pharmacology Vol.9 No.5

In horizontal cells (HCs) that were freshly dissociated from goldfish retina, two types of voltagedependent calcium currents ($I_{Ca}$) were recorded using a patch-clamping configuration: a transient type current and a sustained type current. The cell was held at -40 mV, and the prepulse step of -90 mV was applied before command pulse between -65 and +55 mV. The transient $Ca^{2+}$ current was activated by depolarization to around -50 mV from a prepulse voltage of -90 mV lasting at least 400 ms and reached a maximal value near -25 mV. On the other hand, the sustained $Ca^{2+}$ current was induced by pre-inactivation for less than 10 ms duration. Its activation started near -10 mV and peaked at +20 mV. $Co^{2+}$ (2 mM) suppressed both of these two components, but nifedipine ($20{\mu}M$), L-type $Ca^{2+}$ channel antagonist, blocked only the sustained current. Based on the activation voltage and the pharmacolog$I_{Ca}$l specificity, the sustained current appears to be similar to L-type $I_{Ca}$ and the transient type to T-type $I_{Ca}$. This study is the first to confirm that transient type $I_{Ca}$ together with the sustained one is present in HCs dissociated from goldfish retina.

Korean Red Ginseng Induced Cardioprotection against Myocardial Ischemia in Guinea Pig

Lim, Kyu Hee,Kang, Chang-Won,Choi, Jin-Yong,Kim, Jong-Hoon The Korean Society of Pharmacology 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.4

This study was designed to evaluate the protective effect of Korean red ginseng (KRG) against ischemia/reperfusion (I/R) injury in isolated guinea pig heart. KRG has been shown to possess various ginsenosides, which are the major components of Panax ginseng. These components are known naturally occurring compounds with beneficial effects and free radical scavenging activity. The heart was induced to ischemia for 60 min, followed by 120 min reperfusion. The hearts were randomly allocated into five groups (n=8 for each group): normal control (N/C), KRG control, I/R control, 250 mg/kg KRG group and 500 mg/kg KRG group. KRG significantly increased hemodynamics parameters such as aortic flow, coronary flow and cardiac output. Moreover, KRG significantly increased left ventricular systolic pressure (LVSP), the maximal rate of contraction (+dP/$dt_{max}$) and maximal rate of relaxation (-dP/$dt_{max}$). Also, treatment of KRG ameliorated electrocardiographic index such as the QRS, QT and RR intervals. Moreover, KRG significantly suppressed the lactate dehydrogenase, creatine kinase-MB fraction and cardiac troponin I and ameliorated the oxidative stress markers such as malondialdehyde and glutathione. KRG was standardized through ultra performance liquid chromatograph analysis for its major ginsenosides. Taken together, KRG has been shown to prevent cardiac injury by normalizing the biochemical and oxidative stress.

Korean Red Ginseng Water Extract Restores Impaired Endothelial Function by Inhibiting Arginase Activity in Aged Mice

Choi, Kwanhoon,Yoon, Jeongyeon,Lim, Hyun Kyo,Ryoo, Sungwoo The Korean Society of Pharmacology 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.2

Cardiovascular disease is the prime cause of morbidity and mortality and the population ages that may contribute to increase in the occurrence of cardiovascular disease. Arginase upregulation is associated with impaired endothelial function in aged vascular system and thus may contribute to cardiovascular disease. According to recent research, Korean Red Ginseng water extract (KRGE) may reduce cardiovascular disease risk by improving vascular system health. The purpose of this study was to examine mechanisms contributing to age-related vascular endothelial dysfunction and to determine whether KRGE improves these functions in aged mice. Young ($10{\pm}3$ weeks) and aged ($55{\pm}5$ weeks) male mice (C57BL/6J) were orally administered 0, 10, or 20 mg/mouse/day of KRGE for 4 weeks. Animals were sacrificed and the aortas were removed. Endothelial arginase activity, nitric oxide (NO) generation and reactive oxygen species (ROS) production, endothelial nitric oxide synthase (eNOS) coupling, vascular tension, and plasma peroxynitrite production were measured. KRGE attenuated arginase activity, restored nitric oxide (NO) generation, reduced ROS production, and enhanced eNOS coupling in aged mice. KRGE also improved vascular tension in aged vessels, as indicated by increased acetylcholine-induced vasorelaxation and improved phenylephrine-stimulated vasoconstriction. Furthermore, KRGE prevented plasma peroxynitrite formation in aged mice, indicating reduced lipid peroxidation. These results suggest KRGE exerts vasoprotective effects by inhibiting arginase activity and augmenting NO signaling and may be a useful treatment for age-dependent vascular diseases.

Pharmacological evaluation of HM41322, a novel SGLT1/2 dual inhibitor, in vitro and in vivo

Lee, Kyu Hang,Lee, Sang Don,Kim, Namdu,Suh, Kwee Hyun,Kim, Young Hoon,Sim, Sang Soo The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.1

HM41322 is a novel oral sodium-glucose cotransporter (SGLT) 1/2 dual inhibitor. In this study, the in vitro and in vivo pharmacokinetic and pharmacologic profiles of HM41322 were compared to those of dapagliflozin. HM41322 showed a 10-fold selectivity for SGLT2 over SGLT1. HM41322 showed an inhibitory effect on SGLT2 similar to dapagliflozin, but showed a more potent inhibitory effect on SGLT1 than dapagliflozin. The maximum plasma HM41322 level after single oral doses at 0.1, 1, and 3 mg/kg were 142, 439, and 1830 ng/ml, respectively, and the $T_{1/2}$ was 3.1 h. HM41322 was rapidly absorbed and reached the circulation within 15 min. HM41322 maximized urinary glucose excretion by inhibiting both SGLT1 and SGLT2 in the kidney. HM41322 3 mg/kg caused the maximum urinary glucose excretion in normoglycemic mice ($19.32{\pm}1.16mg/g$) at 24 h. In normal and diabetic mice, HM41322 significantly reduced glucose excursion. Four-week administration of HM41322 in db/db mice reduced HbA1c in a dose dependent manner. Taken together, HM41322 showed a favorable preclinical profile of postprandial glucose control through dual inhibitory activities against SGLT1 and SGLT2.

Toward a grey box approach for cardiovascular physiome

Hwang, Minki,Leem, Chae Hun,Shim, Eun Bo The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.5

The physiomic approach is now widely used in the diagnosis of cardiovascular diseases. There are two possible methods for cardiovascular physiome: the traditional mathematical model and the machine learning (ML) algorithm. ML is used in almost every area of society for various tasks formerly performed by humans. Specifically, various ML techniques in cardiovascular medicine are being developed and improved at unprecedented speed. The benefits of using ML for various tasks is that the inner working mechanism of the system does not need to be known, which can prove convenient in situations where determining the inner workings of the system can be difficult. The computation speed is also often higher than that of the traditional mathematical models. The limitations with ML are that it inherently leads to an approximation, and special care must be taken in cases where a high accuracy is required. Traditional mathematical models are, however, constructed based on underlying laws either proven or assumed. The results from the mathematical models are accurate as long as the model is. Combining the advantages of both the mathematical models and ML would increase both the accuracy and efficiency of the simulation for many problems. In this review, examples of cardiovascular physiome where approaches of mathematical modeling and ML can be combined are introduced.

Cytochrome P450 2E1 Activity in a Korean Population

Muhn, Dou-Hyun,Chae, Ji-Min,Bahn, Jae-Yong,Song, Hae-Jung,Kim, Hyung-Kee,Kwon, Jun-Tack,Sohn, Dong-Ryul The Korean Society of Pharmacology 1997 The Korean Journal of Physiology & Pharmacology Vol.1 No.5

Cytochrome P450 2E1 (CYP2E1) is involved in the toxicity and carcinogenicity of a number of solvents and xenobiotics. Like the various types of oxidation pharmacogenetics, the activity of the enzyme shows a discernible interindividual and interethnic variation. However, no pharmacogenetic information on CYP2E1 polymorphism has been available from a Korean population. The aim of this study was to explore the pharmacogenetics of CYP2E1 polymorphism in a native Koreans after an oral 400 mg dose of chlorzoxazone administered to 128 subjects. Urine samples were collected during the subsequent 8-hour period and urinary concentrations of chlorzoxazone and 6-hydroxychlorzoxazone were determined by a high performance liquid chromatography with an ultraviolet detector. The limit of detection in the samples was found to be $0.5\;{\mu}g/ml$. The mean value of the 6-hydroxychlorzoxazone excreted in 8 hr urine expressed as the percentage was 48.2 13.8%. The frequency distribution of percentage of the administered dose excreted as the 6-hydroxy metabolite was unimodally distributed in the subjects studied. However, the values showed wide (7-fold) interindividual difference, ranged from 11.6% to 79.8% of the dose of chlorzoxazone. Thus, it was considered that the pharmacogenetic characteristics of CYP2E1 in a Korean population did not represent multimodal distribution in the 6-hydroxychlorzoxazone excreted in 8-hr urine expressed as the percentage. And the activity of the CYP2E1 in a Korean population seemed to be less compared with that of the Caucasian subjects.

Potassium Currents in Isolated Deiters' Cells of Guinea Pig

Chung, Jong Woo,Nam, Eui Chol,Kim, Won Tae,Youm, Jae Boum,Leem, Chae Hun The Korean Society of Pharmacology 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.6

Deiters' cells are the supporting cells in organ of Corti and are suggested to play an important role in biochemical and mechanical modulation of outer hair cells. We successfully isolated functionally different $K^+$ currents from Deiters' cells of guinea pig using whole cell patch clamp technique. With high $K^+$ pipette solution, depolarizing step pulses activated strongly outward rectifying currents which were dose-dependently blocked by clofilium, a class III anti-arrhythmic $K^+$ channel blocker. The remaining outward current was transient in time course whereas the clofilium-sensitive outward current showed slow inactivation and delayed rectification. Addition of 5 mM tetraethylammonium (TEA) further blocked the remaining current leaving a very fast inactivating transient outward current. Therefore, at least three different types of $K^+$ current were identified in Deiters' cells, such as fast activating and fast inactivating current, fast activating slow inactivating current, and very fast inactivating transient outward current. Physiological role of them needs to be established.

The change of signaling pathway on the electrical stimulated contraction in streptozotocin-induced bladder dysfunction of rats

Han, Jong Soo,Min, Young Sil,Kim, Gil Hyung,Chae, Sang-hyun,Nam, Yoonjin,Lee, Jaehwi,Lee, Seok-Yong,Sohn, Uy Dong The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.5

Bladder dysfunction is a common complication of diabetes mellitus (DM). However, there have been a few studies evaluating bladder smooth muscle contraction in DM in the presence of pharmacological inhibitors. In the present study, we compared the contractility of bladder smooth muscle from normal rats and DM rats. Furthermore, we utilized pharmacological inhibitors to delineate the mechanisms underlying bladder muscle differences between normal and DM rats. DM was established in 14 days after using a single injection of streptozotocin (65 mg/kg, intraperitoneal) in Sprague-Dawley rats. Bladder smooth muscle contraction was induced electrically using electrical field stimulation consisting of pulse trains at an amplitude of 40 V and pulse duration of 1 ms at frequencies of 2-10 Hz. In this study, the pharmacological inhibitors atropine (muscarinic receptor antagonist), U73122 (phospholipase C inhibitor), DPCPX (adenosine $A_1$ receptor antagonist), udenafil (PDE5 inhibitor), prazosin (${\alpha}_1$-receptor antagonist), verapamil (calcium channel blocker), and chelerythrine (protein kinase C inhibitor) were used to pretreat bladder smooth muscles. It was found that the contractility of bladder smooth muscles from DM rats was lower than that of normal rats. In addition, there were significant differences in percent change of contractility between normal and DM rats following pretreatment with prazosin, udenafil, verapamil, and U73122. In conclusion, we suggest that the decreased bladder muscle contractility in DM rats was a result of perturbations in $PLC/IP_3$-mediated intracellular $Ca^{2+}$ release and PDE5 activity.