Eun-Young Kim

Asia-Pacific mussel watch for emerging pollutants: Distribution of synthetic musks and benzotriazole UV stabilizers in Asian and US coastal waters

We analyzed 68 green and blue mussels collected from Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Vietnam and the USA during 2003 and 2007, to elucidate the occurrence and widespread distributions of emerging pollutants, synthetic musks and benzotriazole UV stabilizers (BUVSs) in Asia-Pacific coastal waters. Synthetic musks and BUVSs were detected in mussels from all countries, suggesting their ubiquitous contamination and widespread distribution. High concentrations of musks and BUVSs were detected in mussels from Japan and Korea, where the levels were comparable or greater than those of PCBs, DDTs and PBDEs. Significant correlations were found between the concentrations of HHCB and AHTN, and also between the concentrations of UV-327 and UV-328, which suggest similar sources and compositions of these compounds in commercial and industrial products. To our knowledge, this is the first study of large-scale monitoring of synthetic musks and BUVSs in Asia-Pacific coastal waters.

Cytochrome P450 CYP2 genes in the common cormorant: Evolutionary relationships with 130 diapsid CYP2 clan sequences and chemical effects on their expression.

Cytochrome P450 CYP2 family enzymes are important in a variety of physiological and toxicological processes. CYP2 genes are highly diverse and orthologous relationships remain clouded among CYP2s in different taxa. Sequence and expression analyses of CYP2 genes in diapsids including birds and reptiles may improve understanding of this CYP family. We sought CYP2 genes in a liver cDNA library of the common cormorant (Phalacrocorax carbo), and in the genomes of other diapsids, chicken (Gallus gallus), zebra finch (Taeniopygia guttata), and anole lizard (Anolis carolinensis), for phylogenetic and/or syntenic analyses. Screening of the cDNA library yielded four CYP2 cDNA clones that were phylogenetically classified as CYP2C45, CYP2J25, CYP2AC1, and CYP2AF1. There are numerous newly identified diapsid CYP2 genes that include genes related to the human CYP2Cs, CYP2D6, CYP2G2P, CYP2J2, CYP2R1, CYP2U1, CYP2W1, CYP2AB1P, and CYP2AC1P. Syntenic relationships show that avian CYP2Hs are orthologous to CYP2C62P in humans, CYP2C23 in rats, and Cyp2c44 in mice, and suggest that avian CYP2Hs, along with human CYP2C62P and mouse Cyp2c44, could be renamed as CYP2C23, based upon the nomenclature rules. Analysis of sequence and synteny identifies cormorant and finch CYPs that are apparent orthologs of phenobarbital-inducible chicken CYP2C45. Transcripts of all four cormorant CYP2 genes were detected in the liver of birds from Lake Biwa, Japan. The transcript levels bore no significant relationship to levels of chlorinated organic pollutants in the liver, including polychlorinated biphenyls and dichlorodiphenyltrichloroethane and its metabolites. In contrast, concentrations of perfluorooctane sulfonate and perfluorononanoic acid were negatively correlated with levels of CYP2C45 and/or CYP2J25, suggesting down-regulation of expression by these environmental pollutants. This study expands our view of the phylogeny and evolution of CYP2s, and provides evolutionary insight into the chemical regulation of CYP2 gene expression in diapsids including birds.

Lithospermi radix Extract Inhibits Histamine Release and Production of Inflammatory Cytokine in Mast Cells

Lithospermi radix (LR, Borraginaceae, the root of Lithospermum erythrorhizon Siebold. et Zuccarinii) is used in herbal medicine to treat such conditions as eczema, skin burns and frostbite. This study investigates the effects of LR on the anti-allergy mechanism. LR inhibited the release of histamine from rat peritoneal mast cells by compound 48/80 in a dose-dependent manner. LR orally administered at 6.59 mg/100 g also inhibited the anti-DNP IgE-induced passive cutaneous anaphylaxis reaction. LR inhibited the PMA plus A23187-induced increase in IL-6, IL-8, and TNF-α expression in HMC-1 cells. In addition, LR also inhibited nuclear factor-kappa B (NF-κB) activation and IκB-α degradation. These results show that LR had an inhibitory effect on the atopic allergic reaction. Furthermore, the in vivo and in vitro anti-allergic effect of LR suggests possible therapeutic applications of this agent for inflammatory allergic diseases.

Prevalence of the metabolic syndrome among South Korean adults: the Ansan study

The clustering of impaired glucose metabolism, elevated triglycerides, low HDL-cholesterol, high blood pressure, and central obesity constitutes the metabolic syndrome (MS). Because people with MS are at increased risk for developing diabetes mellitus (DM) and cardiovascular disease (CVD) as well as increased mortality and morbidity from CVD and all causes [1–4], the estimation of MS prevalence may be the first step towards developing the strategies of caring for these non-communicable diseases. Recently, the World Health Organization (WHO) [5] and the National Cholesterol Education Program (NCEP) expert panel in the USA [6] published working definitions of MS. Using these definitions, many epidemiological studies have found that the estimation of MS prevalence varies widely from 7.1% to 41.6% across different populations [4,6–10]. Because of higher energy intakes, lower physical activity and subsequent increased obesity prevalence, MS is becoming increasingly common, and thus an important risk factor for degenerative diseases such as DM and CVD in the South Korean population. However, there are few data of MS prevalence in South Korean population [10]. Furthermore, existing data cannot be directly compared with those of other populations because of the use of different definitions. In this study, we employed NCEP definitions of MS and estimated MS prevalence in an attempt to compare these with previously published data. A total of 1880 subjects aged 18–84 years were randomly selected from June 1999 to June 2001 for comprehensive health screening in the Ansan Health Centre as described [11]. Because of the availability of MS components, only 1798 subjects (754 men and 1044 women) aged 46.4 ± 14.2 years (mean ± SD ) were subjected to analysis of MS prevalence using either the NCEP definition or the modified NCEP (Asian-NCEP) definition with a new waist circumference (WC) ≥ 90 cm for men and ≥ 80 cm for women according to International Obesity Task Force (IOTF) central obesity criteria for Asians [12]; IOTF has suggested that some Asians may be predisposed to MS even at lower levels of abdominal obesity with WC ≥ 90 cm for men and ≥ 80 cm for women because health risks associated with obesity occur at a lower body mass index and/or a lower WC in Asian populations. Using the NCEP definition with WC > 102 cm for men and > 88 cm for women, MS prevalence in the South Korean population was 21.1% for all subjects, 22.3% for men, and 20.3% for women, and differed little between men and women (Table 1). The MS prevalence among Korean men was similar to that among American (24%) [8] and Turkish men (27%) [7], but higher than among Finnish men (13.7%) [4]. MS prevalence among South Korean women was similar to that among American women (23.4%) [8], but lower than among Turkish women (38.6%) [7]. Using the Asian-NCEP definition, crude MS prevalence appears to have increased approximately 1.5-fold, showing 31.8% for all subjects, 35.3% for men, and 29.2% for women (Table 1), with no significant differences between men and women. MS prevalence among South Koreans was likely to be lower than the recent data of urban Asian Indians (41.6%), although the latter used slightly different Asian-NCEP definitions with WC ≥ 90 cm for men and ≥ 85 cm for women [13]. There was one previous report showing 18.9% of MS prevalence in the South Korean population [10]. However, this value also cannot be compared with our current data because their study used the WHO definition [5]. Age-specific MS prevalence among the South Korean population increased from 3.1% among participants aged 18–29 years to 46.7% among participants aged ≥ 70 years (Table 1). This pattern of increase, however, was not the same as that from the National Health and Nutrition Examination Survey III (NHANES III) study [8]. We found MS prevalence was significantly higher among South Korean men than women up to the age of 50, after which a reversal was noted. No significant sex-specific difference in MS prevalence was found in the NHANES III study [8]. A detailed mechanism is yet to be elucidated for an interesting finding of an abrupt increase in MS prevalence among Korean women at age 50. One interesting finding in this study is that MS prevalence among the South Korean population was not less than that among western populations such as Americans [8] and Finns [4]. One possible explanation for this uniformly high value of MS prevalence is that the global trend of increasing overall and abdominal obesity currently includes South Korea. Alternatively, the data from the NHANES III [8] and the Finnish study [4] may have been underestimated relative to our data, because of the sampling time frames used. The NHANES III data were collected from population studies conducted from 1988 to 1994 and the Finnish study from 1984 to 1989. Thus, abdominal obesity and perhaps MS prevalence would have increased since then unless national intervention programmes were undertaken. Our finding of a relatively higher than expected prevalence of MS among the South Korean population highlights an urgent need for nationwide efforts such as a weight control and increased physical activity to reduce MS prevalence and subsequent MS-related DM and CVD in South Korea.

Neuroprotective effects of overexpressed cyclophilin B against Aβ-induced neurotoxicity in PC12 cells

Accumulated amyloid-β (Aβ) is a well-known cause of neuronal apoptosis in Alzheimer disease and functions in part by generating oxidative stress. Our previous work suggested that cyclophilin B (CypB) protects against endoplasmic reticulum (ER) stress. Therefore, in this study we examined the ability of CypB to protect against Aβ toxicity. CypB is present in the neurons of rat and mouse brains, and treating neural cells with Aβ(25-35) mediates apoptotic cell death. Aβ(25-35)-induced neuronal toxicity was inhibited by the overexpression of CypB as measured by cell viability, apoptotic morphology, sub-G1 cell population, intracellular reactive oxygen species accumulation, activated caspase-3, PARP cleavage, Bcl-2 proteins, mitogen-activated protein kinase (MAPK) activation, and phosphoinositide 3-kinase (PI-3-K) activation. CypB/R95A PPIase mutants did not reduce Aβ(25-35) toxicity. We showed that Aβ(25-35)-induced apoptosis is more severe in a CypB knockdown model, confirming that CypB protects against Aβ(25-35)-induced toxicity. Consequently, these findings suggest that CypB may protect against Aβ toxicity by its antioxidant properties, by regulating MAPK and PI-3-K signaling, and through the ER stress pathway.

Aqueous extracts of Anemarrhena asphodeloides stimulate glucagon-like pepetide-1 secretion in enteroendocrine NCI-H716 cells

Anemarrhena asphodeloides (AA), a bitter taste herbal medicine, has been prescribed in traditional oriental medicine to treat diabetes mellitus. Here, AA was extracted and fractionated to investigate its effects on the stimulation of glucagon-like peptide-1 (GLP-1) secretion in enteroendocrine cells. GLP-1 is secreted from the human enteroendocrine L cells to the blood in response to ingested nutrients. Because GLP-1 increases glucose dependent insulin release, it is known as a therapeutic method for the treatment of type II diabetes mellitus. The human enteroendocrine L cell line NCI-H716 expresses various chemoreceptors including the G protein coupled receptor (GPCR). Previous studies suggested that, through the GPCR signaling pathway, the secretion of GLP-1 can be induced in NCI-H716. Accordingly, we studied the GLP-1 stimulation effect of the AA extract and its mode-of-action using the GLP-1 ELISA and microarray. Functional categorization of the microarray data confirmed up or down-regulated gene expressions associated with the GPCR signaling pathway. This study demonstrates that AA extracts have a scientific possibility as a GLP-1 stimulant and thus may have the potential to be a therapeutic herbal medicine for type II diabetes mellitus.

Molecular and Functional Characterization of Aryl Hydrocarbon Receptor Repressor from the Chicken (Gallus gallus): Interspecies Similarities and Differences

The aryl hydrocarbon receptor (AHR) repressor (AHRR) has been recognized as a negative feedback modulator of AHR-mediated responses in fish and mammals. However, the repressive mechanism by the AHRR has not been investigated in other animals. To understand the molecular mechanism of dioxin toxicity and the evolutionary history of the AHR signaling pathway in avian species, the present study addresses chicken AHRR (ckAHRR). The complementary DNA sequence of ckAHRR encodes an 84-kDa protein sharing 29-52% identities with other AHRRs. High levels of ckAHRR messenger RNA were recorded in the kidney and intestine of nontreated chicks. In hepatoma LMH cells, the 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) 50% effective concentration value for ckAHRR induction (0.0016nM) was the same as that for chicken cytochrome P450 1A5 (ckCYP1A5), implying a shared transcriptional regulation of ckAHRR and ckCYP1A5 by chicken AHR (ckAHR). In ckAHRR transient transfection assays, ckAHRR repressed both ckAHR1- and ckAHR2-mediated transcriptional activities. Deletion and mutation assays revealed that basic helix-loop-helix/Per-ARNT-Sim A domains of ckAHRR, particularly 217-402 amino acid residues, are indispensable for the repression, but the AHR nuclear translocator sequestration by ckAHRR and SUMOylation of ckAHRR are not involved in its repressive mechanism. Additionally, subcellular localization assay of ckAHR1-enhanced green fluorescent protein fusion protein showed that ckAHRR did not affect nuclear translocation of the ckAHR1. Furthermore, ckAHRR inhibited the TCDD- and 17β estradiol-enhanced ckCYP1A5 transcription through AHR-estrogen receptor α (ERα) cross talk. Taken together, the function of AHRR is conserved in chicken in terms of the negative regulation of AHR and ERα activities, but its functional mechanism is likely distinct from those of the mammalian and fish homologues.

The effects of Lycii Radicis Cortex on RANKL-induced osteoclast differentiation and activation in RAW 264.7 cells

Post-menopausal osteoporosis is a serious age-related disease. After the menopause, estrogen deficiency is common, and excessive osteoclast activity causes osteoporosis. Osteoclasts are multinucleated cells generated from the differentiation of monocyte/macrophage precursor cells such as RAW 264.7 cells. The water extract of Lycii Radicis Cortex (LRC) is made from the dried root bark of Lycium chinense Mill. and is termed Jigolpi in Korea. Its effects on osteoclastogenesis and post-menopausal osteoporosis had not previously been tested. In the present study, the effect of LRC on receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclast differentiation was demonstrated using a tartrate-resistant acid phosphatase (TRAP) assay and pit formation assay. Moreover, in order to analyze molecular mechanisms, we studied osteoclastogenesis-related markers such as nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos, receptor activator of NF-κB (RANK), TRAP, cathepsin K (CTK), matrix metallopeptidase-9 (MMP-9), calcitonin receptor (CTR) and carbonic anhydrase II (CAII) using RT-qPCR and western blot analysis. Additionally, we also determined the effect of LRC on an ovariectomized (OVX) rat model. We noted that LRC inhibited RANKL-induced osteoclast differentiation via suppressing osteoclastogenesis-related markers. It also inhibited osteoporosis in the OVX rat model by decreasing loss of bone density and trabecular area. These results suggest that LRC exerts a positive effect on menopausal osteoporosis.

Gene polymorphisms of interleukin-17 and interleukin-17 receptor are associated with end-stage kidney disease.

Background: Inflammation could be a causal factor in progression of chronic kidney disease. To date, there is convincing experimental and clinical evidence to support the notion that interleukin (IL)-17-producing T cells contribute to kidney injury in renal diseases. However, the genetic relationship between end-stage renal disease (ESRD) and the T-helper 17 pathway has never been studied. In this study, we hypothesized that polymorphisms of IL-17 or their receptors may be associated with ESRD. Methods: A total of 290 nondiabetic ESRD patients and 289 normal controls were included. We analyzed 13 single nucleotide polymorphisms located within the four genes of IL17A, IL17E, IL17RA and IL17RB. Results: The ESRD patients had a significantly higher allele frequency compared to control subjects for the IL17E rs10137082*C and IL17RA rs4819554*A alleles. Genotyping analysis demonstrated that 2 SNPs among 13 were significantly associated with ESRD after adjusting for age and sex, which were shown by IL17E rs10137082 (odds ratio (OR) 1.48 in codominant 1, OR 1.54 in dominant, OR 1.47 in log-additive) and IL17RA rs4819554 (OR 1.46 in codominant 1, OR 1.79 in codominant 2, OR 1.54 in dominant, OR 1.39 in log-additive). Conclusions: Two polymorphisms within the IL17E and IL17RA genes are associated with ESRD independent of age and sex. This is the first finding to suggest that genetic variations of IL17 genes affect the risk of development of ESRD.

Integrative assessment of potential effects of dioxins and related compounds in wild Baikal seals (Pusa sibirica): application of microarray and biochemical analyses.

We have previously indicated that accumulation of chlorinated dioxins and related compounds (DRCs) induced cytochrome P450 (CYP) 1A1, 1A2 and 1B1 isozymes in the liver of wild Baikal seals (Pusa sibirica). Here we attempt to assess the potential effects of DRCs triggered by the induction of these CYP1 isozymes in this species, using an integrative approach, combining gene expression monitoring and biochemical assays. To screen genes that may potentially respond to the exposure of DRCs, we constructed a custom cDNA oligo array that can target mRNAs in Baikal seals, and monitored hepatic mRNA expression levels in the wild population. Correlation analyses between the hepatic total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) and mRNA levels supported our previous findings that high accumulation of DRCs induces the transcription of CYP1A1, CYP1A2 and CYP1B1 genes. In addition, our integrative assessment indicated that the chronic exposure to DRCs may alter the hepatic transcript levels of genes related to oxidative stress, Fe ion homeostasis, and inflammatory responses. The expression levels of CYP1A2 showed significant positive correlations with levels of malondialdehyde, a biomarker of lipid peroxidation, and of etheno-dA, a DNA adduct, suggesting that the lipid peroxidation may be enhanced through the production of reactive oxygen species (ROS) triggered by CYP1A2 induction. Moreover, there was a positive correlation between heme oxygenase activities and malondialdehyde levels, suggesting the prompted heme degradation by ROS. Fetuin-A levels, which are suppressed by inflammation, showed a significant negative correlation with TEQ levels, and hepcidin levels, which are conversely increased by inflammation, had significant positive correlations with malondialdehyde and etheno-dA levels, implying the progression of inflammation by DRC-induced oxidative stress. Taken together, we propose here that wild Baikal seals may suffer from effects of chronic exposure to DRCs on the induction of CYP1 isozymes, followed by increased oxidative stress, heme degradation and inflammation.