Publications by authors named "Sung-Hun Lee"

35 Publications

Phlogopite-Reinforced Natural Rubber (NR)/Ethylene-Propylene-Diene Monomer Rubber (EPDM) Composites with Aminosilane Compatibilizer.

Polymers (Basel) 2021 Jul 14;13(14). Epub 2021 Jul 14.

Department of Polymer Engineering, School of Chemical and Materials Engineering, The University of Suwon, Hwaseong 18323, Korea.

Rubber compounding with two or more components has been extensively employed to improve various properties. In particular, natural rubber (NR)/ethylene-propylene-diene monomer rubber (EPDM) blends have found use in tire and automotive parts. Diverse fillers have been applied to NR/EPDM blends to enhance their mechanical properties. In this study, a new class of mineral filler, phlogopite, was incorporated into an NR/EPDM blend to examine the mechanical, curing, elastic, and morphological properties of the resulting material. The combination of aminoethylaminopropyltrimethoxysilane (AEAPS) and stearic acid (SA) compatibilized the NR/EPDM/phlogopite composite, further improving various properties. The enhanced properties were compared with those of NR/EPDM/fillers composed of silica or carbon black (CB). Compared with the NR/EPDM/silica composite, the incompatibilized NR/EPDM/phlogopite composite without AEAPS exhibited poorer properties, but NR/EPDM/phlogopite compatibilized by AEAPS and SA showed improved properties. Most properties of the compatibilized NR/EPDM/phlogopite composite were similar to those of the NR/EPDM/CB composite, except for the lower abrasion resistance. The NR/EPDM/phlogopite/AEAPS rubber composite may potentially be used in various applications by replacing expensive fillers, such as CB.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/polym13142318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8309489PMC
July 2021

Expression Profile of Circulating MicroRNAs in Dogs With Cardiac Hypertrophy: A Pilot Study.

Front Vet Sci 2021 9;8:652224. Epub 2021 Apr 9.

Department of Veterinary Internal Medicine, College of Veterinary Medicine, Konkuk University, Seoul, South Korea.

This study aimed to identify the expression profile of circulating microRNAs in dogs with eccentric or concentric cardiac hypertrophy. A total of 291 microRNAs in serum samples of five dogs with myxomatous mitral valve degeneration (MMVD) and five dogs with pulmonic stenosis (PS) were compared with those of five healthy dogs using microarray analysis. Results of microarray analysis revealed up-regulation of cfa-miR-130b [fold change (FC) = 2.13, = 0.014), down-regulation of cfa-miR-375 (FC = 1.51, = 0.014), cfa-miR-425 (FC = 2.56, = 0.045), cfa-miR-30d (FC = 3.02, = 0.047), cfa-miR-151 (FC = 1.89, = 0.023), cfa-miR-19b (FC = 3.01, = 0.008), and cfa-let-7g (FC = 2.53, = 0.015) in MMVD group which showed eccentric cardiac hypertrophy, up-regulation of cfa-miR-346 (FC = 2.74, = 0.032), down-regulation of cfa-miR-505 (FC = 1.56, = 0.016) in PS group which showed concentric cardiac hypertrophy, and down-regulation of cfa-miR-30c (FC = 3.45, = 0.013 in MMVD group; FC = 3.31, = 0.014 in PS group) and cfa-let-7b (FC = 11.42, = 0.049 in MMVD group; FC = 5.88, = 0.01 in PS group) in both MMVD and PS groups. In addition, the unsupervised hierarchical clustering of differentially expressed microRNAs in each group resulted in complete separation of healthy dogs from dogs with heart diseases. Therefore, eleven microRNAs among 291 microRNAs were identified as differentially expressed circulating microRNAs related to MMVD or PS in dogs. This pilot study demonstrates that the microRNAs identified in this study could be possible candidates for novel biomarker or therapeutic target related to cardiac hypertrophy in dogs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fvets.2021.652224DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8062772PMC
April 2021

Epigenetic Role of Histone Lysine Methyltransferase and Demethylase on the Expression of Transcription Factors Associated with the Epithelial-to-Mesenchymal Transition of Lung Adenocarcinoma Metastasis to the Brain.

Cancers (Basel) 2020 Dec 4;12(12). Epub 2020 Dec 4.

Division of Neuro Oncology, Department of Neurosurgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon 51353, Korea.

Purpose: The objective of this study was to investigate the epigenetic role of histone lysine methylation/demethylation on the expression of epithelial-to-mesenchymal transition (EMT) associated transcriptional factors (TFs) during the metastasis of lung adenocarcinoma to the brain.

Methods: Paired samples of lung adenocarcinoma and brain metastasis (BM) were analyzed in 46 individual patients. Both samples were obtained by surgical resection or biopsy of the lung and brain. The paraffin-fixed formalin-embedded samples were obtained from the pathology archives in our institute. In samples of lung adenocarcinoma and BM, immunohistochemical staining was performed for epithelial markers, mesenchymal markers, EMT-TFs, histone lysine methyltransferase and demethylase.

Results: The immunoreactivity of EMT-TFs such as Slug (15.6% vs. 42.6%, = 0.005), Twist (23.6% vs. 45.9%, = 0.010) and ZEB1 (15.0% vs. 55.9%, = 0.002) was increased in BM compared with that in lung adenocarcinoma. Epigenetic inducers such as H3K4 methyltransferase (MLL4, = 0.018) and H3K36me3 demethylase (UTX, = 0.003) were statistically increased, and epigenetic repressors such as EZH2 (H3K27 methyltransferase, = 0.046) were significantly decreased in BM compared with those in lung adenocarcinoma. The expression of UTX-ZEB1 ( linear = 1.204) and MLL4-Slug ( linear = 0.987) was increased in direct proportion, and EZH2-Twist ( linear = -2.723) decreased in reverse proportion.

Conclusions: The results suggest that certain histone lysine methyltransferase/demethylase, such as MLL4, UTX, and EZH2, regulate the expression of EMT-TFs such as Slug, ZEB1, and Twist epigenetically, which may thereby influence cancer metastasis from the lung to the brain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers12123632DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761791PMC
December 2020

Efficient mutation screening for cervical cancers from circulating tumor DNA in blood.

BMC Cancer 2020 Jul 27;20(1):694. Epub 2020 Jul 27.

Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Republic of Korea.

Background: Early diagnosis and continuous monitoring are necessary for an efficient management of cervical cancers (CC). Liquid biopsy, such as detecting circulating tumor DNA (ctDNA) from blood, is a simple, non-invasive method for testing and monitoring cancer markers. However, tumor-specific alterations in ctDNA have not been extensively investigated or compared to other circulating biomarkers in the diagnosis and monitoring of the CC. Therfore, Next-generation sequencing (NGS) analysis with blood samples can be a new approach for highly accurate diagnosis and monitoring of the CC.

Method: Using a bioinformatics approach, we designed a panel of 24 genes associated with CC to detect and characterize patterns of somatic single-nucleotide variations, indels, and copy number variations. Our NGS CC panel covers most of the genes in The Cancer Genome Atlas (TCGA) as well as additional cancer driver and tumor suppressor genes. We profiled the variants in ctDNA from 24 CC patients who were being treated with systemic chemotherapy and local radiotherapy at the Jeonbuk National University Hospital, Korea.

Result: Eighteen out of 24 genes in our NGS CC panel had mutations across the 24 CC patients, including somatic alterations of mutated genes (ZFHX3-83%, KMT2C-79%, KMT2D-79%, NSD1-67%, ATM-38% and RNF213-27%). We demonstrated that the RNF213 mutation could be used potentially used as a monitoring marker for response to chemo- and radiotherapy.

Conclusion: We developed our NGS CC panel and demostrated that our NGS panel can be useful for the diagnosis and monitoring of the CC, since the panel detected the common somatic variations in CC patients and we observed how these genetic variations change according to the treatment pattern of the patient.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12885-020-07161-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385901PMC
July 2020

Parturition and Morphological Development of Larvae and Juvenile in from Korea.

Dev Reprod 2018 Dec 31;22(4):361-367. Epub 2018 Dec 31.

Marine Technology Undergraduate, Chonnam National University, Yeosu 59626, Korea.

The newborn, larvae were 6.97-8.81, standard length (SL) mm (mean 7.89 mm) and mouth and anuse were open. Dorsal fin rays 15-18 and pectoral fin-rays were counted 8 and had 10-11+21 myotomes, body's bony plate ring being developed strongly in the central axis of myotomes part. 4 days after bearing, the SL was 7.02-9.47 mm (mean 8.24 mm) and nostrils began to open. 12 days after bearing, larvae attained to 8.91-11.2 SL mm (mean 10.0 mm). From this time, their unique predation habit appeared. 21 days bearing, larvae attained to 12.1-14.8 SL mm (mean 13.4 mm) the and thorn of back was enlarged among the plate formed around ring. 41 days bearing, seahorses attained to 17.1-17.8 SL mm (mean 17.4 mm) and the number of body's bony plate ring of the top of rings trunk was 11 and on the tail of them was 33-36, similar to figure of adult.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12717/DR.2018.22.4.361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344358PMC
December 2018

Osteological Development of the Larvae and Juvenile of Trident Goby, .

Dev Reprod 2018 Sep 30;22(3):205-212. Epub 2018 Sep 30.

Marine Technology Undergraduate, Chonnam National University, Yeosu 59626, Korea.

This study is to observe the developmental process of the larval skeleton according to the growth of the trident goby, belonging to the larvae and juveniles and use it as the basic data of the taxonomic study. 8 days after hatching, the parasphenoid was ossified with an average total length of 3.62 mm, and basioccipital began to ossify. Caudal vertebrae and neural spine ossified in vertebra. 17 days after hatching, the average total length of the long hairs was 4.32 mm, pterotic and epiotic were ossified, and interhyal and subopercle were ossified. 52 days after hatching, the average total length of the juvenile was 18.2 mm, and lateral ethmoid, hypohyal ossified, vertebrae were parapophysis, and epural bone was osseous to the bone.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12717/DR.2018.22.3.205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6182230PMC
September 2018

Osteological Development of the Larvae and Juvenile of Bullhead torrent catfish, .

Dev Reprod 2018 Mar 31;22(1):9-18. Epub 2018 Mar 31.

Marine Technology Undergraduate, Chonnam National University, Yeosu 59626, Korea.

This study was conducted to investigate the skeletal development of bullhead torrent catfish, larvae and to utilize them as basic data for the taxonomic study of larvae. Skeletal development was observed by being divided into cranium, visceral skeleton, shoulder girdle bone, pelvic girdle bone and vertebra. On the first day after hatching, the pre-larvae had an average total length of 7.92 mm, and a line-shaped parasphenoid ossified in the cranium. In the jaw bone, the dentary supporting the lower jaw and the maxillary supporting the upper jaw were ossified. In the anterior abdominal vertebrae of the vertebra, seven centrums began to ossify and five neural spines ossified simultaneously. On the 3 day after hatching, pre-larvae had an average total length of 8.95 mm, and the prefrontal ossified in cranium. The number of abdominal vertebrae was increased to 14, and three parapophysis developed from the front side. On the 24th day after hatching, post-larvae had an average total length of 15.2 mm and the epural bone ossified in coccyx. The parhypural bone was ossified, and ossification of coccyx and pelvic girdle bone was completed. On the 30th day after hatching, the average total length of the juvenile was 17.8 mm, and the ossification of cranium and visceral skeleton was all completed while the preorbital and three suborbitals were ossified in the orbital region of the cranium.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12717/DR.2018.22.1.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915771PMC
March 2018

Protein arginine methyltransferase 7-mediated repression maintains Oct4, Nanog, and Sox2 levels in mouse embryonic stem cells.

J Biol Chem 2018 03 29;293(11):3925-3936. Epub 2018 Jan 29.

From the Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030 and

The stemness maintenance of embryonic stem cells (ESCs) requires pluripotency transcription factors, including Oct4, Nanog, and Sox2. We have previously reported that protein arginine methyltransferase 7 (PRMT7), an epigenetic modifier, is an essential pluripotency factor that maintains the stemness of mouse ESCs, at least in part, by down-regulating the expression of the anti-stemness microRNA (miRNA) miR-24-2. To gain greater insight into the molecular basis underlying PRMT7-mediated maintenance of mouse ESC stemness, we searched for new PRMT7-down-regulated anti-stemness miRNAs. Here, we show that gene-encoded miR-221-3p and miR-221-5p are anti-stemness miRNAs whose expression levels in mouse ESCs are directly repressed by PRMT7. Notably, both miR-221-3p and miR-221-5p targeted the 3' untranslated regions of mRNA transcripts of the major pluripotency factors Oct4, Nanog, and Sox2 to antagonize mouse ESC stemness. Moreover, miR-221-5p silenced also the expression of its own transcriptional repressor PRMT7. Transfection of miR-221-3p and miR-221-5p mimics induced spontaneous differentiation of mouse ESCs. CRISPR-mediated deletion of the gene, as well as specific antisense inhibitors of miR-221-3p and miR-221-5p, inhibited the spontaneous differentiation of PRMT7-depleted mouse ESCs. Taken together, these findings reveal that the PRMT7-mediated repression of miR-221-3p and miR-221-5p expression plays a critical role in maintaining mouse ESC stemness. Our results also establish miR-221-3p and miR-221-5p as anti-stemness miRNAs that target , , and mRNAs in mouse ESCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA117.000425DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5857983PMC
March 2018

A feedback loop comprising PRMT7 and miR-24-2 interplays with Oct4, Nanog, Klf4 and c-Myc to regulate stemness.

Nucleic Acids Res 2016 12 12;44(22):10603-10618. Epub 2016 Sep 12.

Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA

Self-renewal and pluripotency are two fundamental characteristics of embryonic stem cells (ESCs) and are controlled by diverse regulatory factors, including pluripotent factors, epigenetic regulators and microRNAs (miRNAs). Although histone methyltransferases are key epigenetic regulators, whether and how a histone methyltransferase forms a network with miRNAs and the core pluripotent factor system to regulate ESC stemness is little known. Here, we show that the protein arginine methyltransferase 7 (PRMT7) is a pluripotent factor essential for the stemness of mouse ESCs. PRMT7 repressed the miR-24-2 gene encoding miR-24-3p and miR-24-2-5p by upregulating the levels of symmetrically dimethylated H4R3. Notably, miR-24-3p targeted the 3' untranslated regions (UTRs) of the major pluripotent factors Oct4, Nanog, Klf4 and c-Myc, whereas miR-24-2-5p silenced Klf4 and c-Myc expression. miR-24-3p and miR-24-2-5p also targeted the 3'UTR of their repressor gene Prmt7 miR-24-3p and miR-24-2-5p induced mouse ESC differentiation, and their anti-sense inhibitors substantially reversed spontaneous differentiation of PRMT7-depleted mouse ESCs. Oct4, Nanog, Klf4 and c-Myc positively regulated Prmt7 expression. These findings define miR-24-3p and miR-24-2-5p as new anti-pluripotent miRNAs and also reveal a novel epigenetic stemness-regulatory mechanism in which a double-negative feedback loop consisting of PRMT7 and miR-24-3p/miR24-2-5p interplays with Oct4, Nanog, Klf4 and c-Myc to control ESC stemness.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/nar/gkw788DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5159542PMC
December 2016

Increased expression of the histone H3 lysine 4 methyltransferase MLL4 and the histone H3 lysine 27 demethylase UTX prolonging the overall survival of patients with glioblastoma and a methylated MGMT promoter.

J Neurosurg 2017 05 1;126(5):1461-1471. Epub 2016 Jul 1.

Department of Neurosurgery, Division of Neurooncology, and.

OBJECTIVE The purpose of the present study was to investigate the epigenetic and prognostic roles of an H3K4 methyltransferase (mixed lineage leukemia 4 [MLL4]) and H3K27 demethylase (ubiquitously transcribed tetratricopeptide repeat gene on X chromosome [UTX]) in progression-free survival (PFS) and overall survival (OS) of patients with glioblastoma (GBM) who were treated with radiotherapy, chemotherapy, or both after resection. In addition, the authors examined methylation at the promoter of the O-6-methylguanine-DNA methyltransferase ( MGMT) gene and other prognostic factors predicting length of PFS and OS in these patients. METHODS The medical records of 76 patients having a new diagnosis of histologically ascertained GBM in the period of January 2002 to December 2013 at the authors' institution were retrospectively reviewed. Immunohistochemical staining for MLL4 and UTX was performed on archived paraffin-embedded tissues obtained by biopsy or resection. The methylation status of the MGMT promoter in these tissues was determined by methylation-specific PCR analysis. RESULTS During the follow-up period (mean length 18.1 months, range 4.1-43.5 months), 68 (89.5%) of the patients died. The MGMT promoter was methylated in 49 patients (64.5%) and unmethylated in 27 (35.5%). The immunoreactivity pattern of UTX was identical to that of MLL4; increased expression of these 2 proteins was observed in samples from 34 patients (44.7%) and decreased expression in 42 patients (55.3%). The mean length of PFS was 9.2 months (95% CI 6.8-11.6 months). Extent of surgery, recursive partitioning analysis (RPA) class, and methylation status of the MGMT promoter were all associated with increased PFS in the multivariate analysis of factors predicting PFS. The mean length of OS was 18.6 months (95% CI 14.3-22.9 months). Patient age (p = 0.004), WHO performance status score (p = 0.019), extent of surgery (p = 0.007), RPA class (p = 0.036), methylation status of the MGMT promoter (p = 0.010), and increased expression of UTX-MLL4 (p = 0.001) were significantly associated with increased OS in multivariate analysis. Interestingly, in patients with an unmethylated MGMT promoter, immunoreactivity of UTX-MLL4 was not associated with changes in OS (p = 0.350). However, in the patients with a methylated MGMT promoter, increased UTX-MLL4 expression was strongly associated with increased OS (p < 0.001). CONCLUSIONS The results of this study suggest that increased expression of UTX-MLL4 positively influences the outcome of patients with GBM having a methylated MGMT promoter. Therefore, UTX-MLL4 immunoreactivity could be a useful predictor of the response to conventional treatment with radiotherapy or chemotherapy among GBM patients whose tumors have a methylated MGMT promoter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2016.4.JNS1652DOI Listing
May 2017

The application of catalyst-recovered SnO2 as an anode material for lithium secondary batteries.

Environ Sci Pollut Res Int 2016 Aug 15;23(15):15015-22. Epub 2016 Apr 15.

Department of Chemistry, University of Ulsan, Ulsan, 680-749, Korea.

We studied the electrochemical characteristics of tin dioxide (SnO2) recovered from waste catalyst material which had been previously used in a polymer synthesis reaction. In order to improve the electrochemical performance of the SnO2 anode electrode, we synthesized a nanocomposite of recovered SnO2 and commercial iron oxide (Fe2O3) (weight ratio 95:5) using a solid state method. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) analyses revealed an additional iron oxide phase within a porous nanocomposite architecture. The electrochemical characterizations were based on galvanostatic charge-discharge (CD) curves, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). In the first discharge, the capacity of the SnO2-Fe2O3 nanocomposite was 1700 mAh g(-1), but was reduced to about 1200 mAh g(-1) in the second discharge. Thereafter, a discharge capacity of about 1000 mAh g(-1)was maintained up to the 20th cycle. The SnO2-Fe2O3 nanocomposite showed better reversible capacities and rate capabilities than either the recovered SnO2 or commercial Fe2O3 nanoparticle samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-016-6640-2DOI Listing
August 2016

An essential role for UTX in resolution and activation of bivalent promoters.

Nucleic Acids Res 2016 05 13;44(8):3659-74. Epub 2016 Jan 13.

Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA Cancer Biology Program,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA

Trimethylated histone H3 lysine 27 (H3K27me3) is linked to gene silencing, whereas H3K4me3 is associated with gene activation. These two marks frequently co-occupy gene promoters, forming bivalent domains. Bivalency signifies repressed but activatable states of gene expression and can be resolved to active, H3K4me3-prevalent states during multiple cellular processes, including differentiation, development and epithelial mesenchymal transition. However, the molecular mechanism underlying bivalency resolution remains largely unknown. Here, we show that the H3K27 demethylase UTX (also called KDM6A) is required for the resolution and activation of numerous retinoic acid (RA)-inducible bivalent genes during the RA-driven differentiation of mouse embryonic stem cells (ESCs). Notably, UTX loss in mouse ESCs inhibited the RA-driven bivalency resolution and activation of most developmentally critical homeobox (Hox) a-d genes. The UTX-mediated resolution and activation of many bivalent Hox genes during mouse ESC differentiation were recapitulated during RA-driven differentiation of human NT2/D1 embryonal carcinoma cells. In support of the importance of UTX in bivalency resolution, Utx-null mouse ESCs and UTX-depleted NT2/D1 cells displayed defects in RA-driven cellular differentiation. Our results define UTX as a bivalency-resolving histone modifier necessary for stem cell differentiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/nar/gkv1516DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4856969PMC
May 2016

The Pterional-Transsylvian Approach for Tumor in the Temporal Horn: A Case Report.

Brain Tumor Res Treat 2015 Oct 30;3(2):118-21. Epub 2015 Oct 30.

Department of Neurosurgery, Kosin University Gospel Hospital, Busan, Korea.

A variety of surgical approaches to temporal horn tumors of the lateral ventricle have been described. Magnetic resonance imaging (MRI) and angiography are the preferred modalities for preoperative evaluation and provide important information for the choice of surgical approach. A 59-year-old man was referred to our hospital due to confusion and gait disturbance. On enhanced MRI, a homogeneous enhanced solitary mass was observed within the temporal horn of the left lateral ventricle with transependymal extension. The lesion was accompanied by increased hypervascular tumor blush on preoperative cerebral angiography. Subtotal removal of the temporal horn tumor was performed because the lesion was identified as lymphoma during surgery. The postoperative course was un-eventful. The patient was referred to the oncology department for conventional chemotherapy. Adjuvant chemotherapy improved the clinical outcome. The pterional-transsylvian approach was beneficial for partial removal of the tumor and tissue diagnosis in this case.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.14791/btrt.2015.3.2.118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4656888PMC
October 2015

Epigenetic Role of Histone 3 Lysine Methyltransferase and Demethylase in Regulating Apoptosis Predicting the Recurrence of Atypical Meningioma.

J Korean Med Sci 2015 Aug 15;30(8):1157-66. Epub 2015 Jul 15.

Department of Neurosurgery and Division of Neurooncology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.

Alteration of apoptosis is related with progression and recurrence of atypical meningiomas (AMs). However, no comprehensive study has been conducted regarding histone modification regulating apoptosis in AMs. This study aimed to determine the prognostic values of certain apoptosis-associated factors, and examine the role of histone modification on apoptosis in AMs. The medical records of 67 patients with AMs, as diagnosed during recent 13 yr, were reviewed retrospectively. Immunohistochemical staining was performed on archived paraffin-embedded tissues for pro-apoptotic factors (CASP3, IGFBP, TRAIL-R1, BAX, and XAF1), anti-apoptotic factors (survivin, ERK, RAF1, MDM2, and BCL2), and the histone modifying enzymes (MLL2, RIZ, EZH1, NSD2, KDM5c, JMJD2a, UTX, and JMJD5). Twenty-six (38.8%) patients recurred during the follow-up period (mean duration 47.7 months). In terms of time-to-recurrence (TTR), overexpression of CASP3, TRAIL-R1, and BAX had a longer TTR than low expression, and overexpression of survivin, MDM2, and BCL2 had a shorter TTR than low expression (P<0.05). Additionally, overexpression of MLL2, UTX, and JMJ5 had shorter TTRs than low expression, and overexpression of KDM5c had a longer TTR than low expression. However, in the multi-variate analysis of predicting factors for recurrence, low expression of CASP3 (P<0.001), and BAX (P<0.001), and overexpression of survivin (P=0.007), and MDM2 (P=0.037) were associated with recurrence independently, but any enzymes modifying histone were not associated with recurrence. Conclusively, this study suggests certain apoptosis-associated factors should be associated with recurrence of AMs, which may be regulated epigenetically by histone modifying enzymes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3346/jkms.2015.30.8.1157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4520948PMC
August 2015

Egg Development and Morphology of Larva and Juvenile of the Oryzias latipes.

Dev Reprod 2014 Sep;18(3):173-8

Aquaculture Program, College of Fisheries and Ocean Sciences, Chonnam National University, Chonnam 550-749, Korea.

In order to monitor the developmental features of embryos, larvae, and juveniles of Oryzias latipes (Temminck and Schlegel), Oryzias latipes was caught in river of Shinduck-dong, Yeosu-si, Jeollanam-do, on May 2011, and experiments were carried out in Ichthyology laboratory at Chonnam National University. The blastodisc step was the first level for natural spawning. The optic vesicle, Kupffer's vesicle, myotome began to appear 75 hours 57 minutes later. After blastodisc development, the pectoral fins were made at 143 hours 37 minutes and the tail was separated started at the same time. Hatching was observed at 167 hours 27 minutes after blastodisc. The total length of the hatched larvae was 4.95~5.10 mm (mean, 5.01 mm), the mouth and anus were opened. Larvae used yolk completely after 3 days after hatching. The total length larvae was 5.45~5.56 mm (mean, 5.52 mm) after 8 days after hatching, and appeared the stems for tail. The stems pectoral, anal fin were showed after 14 days and the stems dorsal, ventral fin were appeared after 19 days. For 35 days after hatching, the total length of larvae 13.95~15.30 mm (mean, 14.64 mm), and at this time, fins and body were transferred like the adult Oryzias latipes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12717/DR.2014.18.3.173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282211PMC
September 2014

LINE-1 retrotransposons and let-7 miRNA: partners in the pathogenesis of cancer?

Front Genet 2014 7;5:338. Epub 2014 Oct 7.

Department of Molecular Bioscience, John Curtin School of Medical Research, The Australian National University Canberra, ACT, Australia.

Long interspersed nuclear element-1 (LINE-1 or L1) retrotransposons are insertional mutagens capable of altering the genomic landscape in many ways. Activation of the normally silent LINE-1 retrotransposon is associated with a high level of cancer-associated DNA damage and genomic instability. Studies of LINE-1 have so far focused mainly on changes in gene expression, and our knowledge of its impact on functional non-coding RNAs is in its infancy. However, current evidence suggests that a significant number of human miRNAs originate from retrotransposon sequences. Furthermore, LINE-1 is generally not expressed in normal tissues while its expression is widespread in epithelial cancers. Based on our recent studies, we demonstrate a functional link between aberrant LINE-1 expression and deregulation of let-7 miRNA expression. Since the expression of let-7 is modulated by LINE-1 activity, we discuss possible mechanisms for this effect and how the silencing of LINE-1 activation could provide new therapeutic options for cancer treatment. Based on the deep sequencing of small RNAs in parallel with gene expression profiling in breast cancer cells, we have identified potential pathways linking L1 activity to let-7 processing and maturation and ultimately to the control of stemness in human cancer cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fgene.2014.00338DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4188135PMC
October 2014

Results of immunohistochemical staining for cell cycle regulators predict the recurrence of atypical meningiomas.

J Neurosurg 2014 Nov 22;121(5):1189-200. Epub 2014 Aug 22.

Department of Neurosurgery and Division of Neurooncology, and.

Object: The aim of this study was to evaluate the role of certain cell-cycle regulatory proteins in the recurrence of atypical meningiomas. These proteins were analyzed with immunohistochemical staining to identify predisposing factors for the recurrence of atypical meningiomas.

Methods: The authors retrospectively reviewed the medical records of patients with atypical meningiomas diagnosed in the period from January 2000 to June 2012 at the Department of Neurosurgery at Samsung Changwon Hospital and Dong-A University Medical Center. Clinical data included patient sex and age at the time of surgery, presenting symptoms at diagnosis, location and size of tumor, extent of surgery, use of postoperative radiotherapy, duration of follow-up, and recurrence. Immunohistochemical staining for cell-cycle regulatory proteins (p16, p15, p21, p27, cyclin-dependent kinase [CDK] 4 and 6, phosphorylated retinoblastoma [pRB] protein, and cyclin D1) and proliferative markers (MIB-1 antigen, mitosis, and p53) was performed on archived paraffin-embedded tissues obtained during resection. The recurrence rate and time to recurrence were assessed using Kaplan-Meier analysis.

Results: Of the 67 atypical meningiomas eligible for analysis, 26 (38.8%) recurred during the follow-up period (mean duration 47.7 months, range 8.4-132.1 months). Immunohistochemically, there was overstaining for p16 in 44 samples (65.7%), for p15 in 21 samples (31.3%), for p21 in 25 samples (37.3%), for p27 in 32 samples (47.8%), for CDK4 in 38 samples (56.7%), for CDK6 in 26 samples (38.8%), for pRB protein in 42 samples (62.7%), and for cyclin D1 in 49 samples (73.1%). Multivariate analysis using the Cox proportional-hazards regression model showed that incomplete resection (HR 4.513, p < 0.001); immunohistochemical understaining for p16 (HR 3.214, p < 0.001); immunohistochemical overstaining for CDK6 (HR 3.427, p < 0.001), pRB protein (HR 2.854, p = 0.008), and p53 (HR 2.296, p = 0.040); and increased MIB-1 labeling index (HR 2.665, p = 0.013) and mitotic index (HR 2.438, p = 0.024) predicted the recurrence of atypical meningiomas after resection.

Conclusions: Findings in this study indicated that p16, CDK6, and pRB protein were associated with the recurrence of atypical meningiomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2014.7.JNS132661DOI Listing
November 2014

UTX and MLL4 coordinately regulate transcriptional programs for cell proliferation and invasiveness in breast cancer cells.

Cancer Res 2014 Mar 3;74(6):1705-17. Epub 2014 Feb 3.

Authors' Affiliations: Department of Molecular & Cellular Oncology, The University of Texas MD Anderson Cancer Center; Cancer Biology Program, Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas; Graduate Institute of Basic Medical Science, China Medical University, Taichung; and Department of Biotechnology, Asia University, Taichung, Taiwan.

Histone methyltransferases and demethylases reversibly modulate histone lysine methylation, which is considered a key epigenetic mark associated with gene regulation. Recently, aberrant regulation of gene expression by histone methylation modifiers has emerged as an important mechanism for tumorigenesis. However, it remains largely unknown how histone methyltransferases and demethylases coregulate transcriptional profiles for cancer cell characteristics. Here, we show that in breast cancer cells, the histone H3 lysine 27 (H3K27) demethylase UTX (also known as KDM6A) positively regulates gene expression programs associated with cell proliferation and invasion. The majority of UTX-controlled genes, including a cohort of oncogenes and prometastatic genes, are coregulated by the H3K4 methyltransferase mixed lineage leukemia 4 (MLL4, also called ALR, KMT2D, and MLL2). UTX interacted with a C-terminal region of MLL4. UTX knockdown resulted in significant decreases in the proliferation and invasiveness of breast cancer cells in vitro and in a mouse xenograft model. Such defective cellular characteristics of UTX-depleted cells were phenocopied by MLL4 knockdown cells. UTX-catalyzed demethylation of trimethylated H3K27 and MLL4-mediated trimethylation at H3K4 occurred interdependently at cotarget genes of UTX and MLL4. Clinically, high levels of UTX or MLL4 were associated with poor prognosis in patients with breast cancer. Taken together, these findings uncover that coordinated regulation of gene expression programs by a histone methyltransferase and a histone demethylase is coupled to the proliferation and invasion of breast cancer cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-13-1896DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3962500PMC
March 2014

Inhibition of LINE-1 retrotransposon-encoded reverse transcriptase modulates the expression of cell differentiation genes in breast cancer cells.

Breast Cancer Res Treat 2014 Jan 12;143(2):239-53. Epub 2013 Dec 12.

John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.

Long Interspersed Elements (L1 elements) are biologically active retrotransposons that are capable of autonomous replication using their own reverse transcriptase (RT) enzyme. Expression of the normally repressed RT has been implicated in cancer cell growth. However, at present, little is known about the expression of L1-encoded RT activity or the molecular changes that are associated with RT activity in the development of breast cancer. Here, we report that RT activity is widespread in breast cancer cells. The expression of RT protein decreased markedly in breast cancer cells after treatment with the antiretroviral drug, efavirenz. While the majority of cells showed a significant reduction in proliferation, inhibition of RT was also accompanied by cell-specific differences in morphology. MCF7 cells displayed elongated microtubule extensions that adhered tightly to their substrate, while a large fraction of the T47D cells that we studied formed long filopodia projections. These morphological changes were reversible upon cessation of RT inhibition, confirming their dependence on RT activity. We also carried out gene expression profiling with microarrays and determined the genes that were differentially expressed during the process of cellular differentiation. Genes involved in proliferation, cell migration, and invasive activity were repressed in RT-inhibited cells. Concomitantly, genes involved in cell projection, formation of vacuolar membranes, and cell-to-cell junctions were significantly upregulated in RT-inhibited cells. qRT-PCR examination of the mRNA expression of these genes in additional cell lines yielded close correlation between their differential expression and the degree of cellular differentiation. Our study demonstrates that the inhibition of L1-encoded RT can reduce the rate of proliferation and promote differentiation of breast cancer cells. Together, these results provide a direct functional link between the expression of L1 retrotransposons and the development of breast cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10549-013-2812-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3889873PMC
January 2014

Trans-tail regulation of MLL4-catalyzed H3K4 methylation by H4R3 symmetric dimethylation is mediated by a tandem PHD of MLL4.

Genes Dev 2012 Dec;26(24):2749-62

Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.

Mixed-lineage leukemia 4 (MLL4; also called MLL2 and ALR) enzymatically generates trimethylated histone H3 Lys 4 (H3K4me3), a hallmark of gene activation. However, how MLL4-deposited H3K4me3 interplays with other histone marks in epigenetic processes remains largely unknown. Here, we show that MLL4 plays an essential role in differentiating NT2/D1 stem cells by activating differentiation-specific genes. A tandem plant homeodomain (PHD(4-6)) of MLL4 recognizes unmethylated or asymmetrically dimethylated histone H4 Arg 3 (H4R3me0 or H4R3me2a) and is required for MLL4's nucleosomal methyltransferase activity and MLL4-mediated differentiation. Kabuki syndrome mutations in PHD(4-6) reduce PHD(4-6)'s binding ability and MLL4's catalytic activity. PHD(4-6)'s binding strength is inhibited by H4R3 symmetric dimethylation (H4R3me2s), a gene-repressive mark. The protein arginine methyltransferase 7 (PRMT7), but not PRMT5, represses MLL4 target genes by up-regulating H4R3me2s levels and antagonizes MLL4-mediated differentiation. Consistently, PRMT7 knockdown increases MLL4-catalyzed H3K4me3 levels. During differentiation, decreased H4R3me2s levels are associated with increased H3K4me3 levels at a cohort of genes, including many HOXA and HOXB genes. These findings indicate that the trans-tail inhibition of MLL4-generated H3K4me3 by PRMT7-regulated H4R3me2s may result from H4R3me2s's interference with PHD(4-6)'s binding activity and is a novel epigenetic mechanism that underlies opposing effects of MLL4 and PRMT7 on cellular differentiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/gad.203356.112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533079PMC
December 2012

Magnetic, optical and structural property studies of Mn-doped ZnO nanosheets.

J Nanosci Nanotechnol 2012 Jul;12(7):5464-8

School of Nano and Advanced Materials Engineering, Changwon National University, Changwon, Gyeongnam, 641-773, Republic of Korea.

We report the synthesis of pure and Mn doped ZnO in the form of nanosheets using a simple and single step procedure involving a microwave assisted chemical method. As prepared Mn-doped ZnO nanosheets were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible (UV-Vis), Raman spectroscopy and magnetization measurements. The structural studies using XRD and TEM revealed the absence of Mn-related secondary phases and showed that Mn-doped ZnO comprise a single phase nature with wurtzite structure. FESEM and TEM micrographs show that the average diameter of Mn-ZnO assembled nanosheets is about approximately 50 nm, and the length of a Mn-doped ZnO nanosheet building block which is made up of thin mutilayered sheets is around approximately 300 nm. Concerning the Raman scattering spectra, the shift in peak position of E2 (high) mode toward low frequencies due to the Mn doping could be explained well by means of the spatial correlation model. Magnetic measurements showed that Mn-doped ZnO nanosheets exhibit ferromagnetic ordering at or above room temperature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1166/jnn.2012.6248DOI Listing
July 2012

Naturally occurring endo-siRNA silences LINE-1 retrotransposons in human cells through DNA methylation.

Epigenetics 2012 Jul 1;7(7):758-71. Epub 2012 Jul 1.

John Curtin School of Medical Research, The Australian National University, Canberra, Australia.

Long interspersed nuclear element 1 (LINE-1) retrotransposons are mutagens that are capable of generating deleterious mutations by inserting themselves into genes and affecting gene function in the human genome. In normal cells, the activity of LINE-1 retrotransposon is mostly repressed, maintaining a stable genome structure. In contrast, cancer cells are characterized by aberrant expression of LINE-1 retrotransposons, which, in principle, have the potential to contribute to genomic instability. The mechanistic pathways that regulate LINE-1 expression remain unclear. Using deep-sequencing small RNA analysis, we identified a subset of differentially expressed endo-siRNAs that directly regulate LINE-1 expression. Detailed analyses suggest that these endo-siRNAs are significantly depleted in human breast cancer cells compared with normal breast cells. The overexpression of these endo-siRNAs in cancer cells markedly silences endogenous LINE-1 expression through increased DNA methylation of the LINE-1 5'-UTR promoter. The finding that endo-siRNAs can silence LINE-1 activity through DNA methylation suggests that a functional link exists between the expression of endo-siRNAs and LINE-1 retrotransposons in human cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4161/epi.20706DOI Listing
July 2012

Precision spectroscopy of Rb atoms using single comb-line selected from fiber optical frequency comb.

Opt Express 2011 Aug;19(17):15855-63

Department of Physics, Pusan National University, Busan 609-735, Korea.

We demonstrated the selection of a single comb-line from an optical frequency comb (OFC) of a mode-locked femtosecond fiber laser with a 250 MHz pulse repetition rate, and applied for precision spectroscopy of Rb atoms at 1529 nm. The single comb-line was selected from the fiber-OFC with a 1.5 GHz mode-spacing using spectral-mode-filtering and femtosecond laser injection-locking. When the repetition rate of the mode-locked femtosecond fiber laser was scanned over the range of 382.6 Hz at 250 MHz, we observed the double-resonance optical pumping spectra of the 5S(1/2)-5P(3/2)-4D(3/2) transition of Rb atoms using the selected comb-line of an OFC scanned over the range of 300 MHz at 196,037,213.8 MHz.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.19.015855DOI Listing
August 2011

Prescription pattern of NSAIDs and the prevalence of NSAID-induced gastrointestinal risk factors of orthopaedic patients in clinical practice in Korea.

J Korean Med Sci 2011 Apr 28;26(4):561-7. Epub 2011 Mar 28.

Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, Korea.

This is a cross-sectional observational study undertaken to explore the current prescription pattern of non-steroidal anti-inflammatory drugs (NSAIDs) and the prevalence of NSAID-induced gastrointestinal (GI) risk factors of orthopaedic patients in real clinical practice in Korea. Study cohort included 3,140 orthopaedic outpatients at 131 hospitals and clinics between January 2008 and August 2008. A self-administered questionnaire was completed by each patient and physician. A simplified risk scoring scale (the Standardized Calculator of Risk for Events; SCORE) was used to measure patients' risk for GI complications. The pattern of NSAIDs prescription was identified from medical recordings. Forty-five percent of the patients belonged to high risk or very high risk groups for GI complications. The cyclooxygenase-2 enzyme (COX-2) selective NSAID showed a propensity to be prescribed more commonly for high/very high GI risk groups, but the rate was still as low as 51%. In conclusion, physician's considerate prescription of NSAIDs with well-understanding of each patient's GI risk factors is strongly encouraged in order to maximize cost effectiveness and to prevent serious GI complications in Korea. Other strategic efforts such as medical association-led education programs and application of Korean electronic SCORE system to hospital order communication system (OCS) should also be accompanied in a way to promote physician's attention.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3346/jkms.2011.26.4.561DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3069577PMC
April 2011

Cardioprotective effects of the novel Na+/H+ exchanger-1 inhibitor KR-32560 in a perfused rat heart model of global ischemia and reperfusion: Involvement of the Akt-GSK-3beta cell survival pathway and antioxidant enzyme.

Arch Pharm Res 2010 Aug 28;33(8):1241-51. Epub 2010 Aug 28.

Department of Applied Biochemistry, Division of Life Science, College of Biomedical and Health Science, Konkuk University, Chungju, 380-701, Korea.

To investigate the cardioprotective effects and mechanism of action of KR-32560 {[5-(2-methoxy-5-fluorophenyl)furan-2-ylcarbonyl]guanidine}, a newly synthesized NHE-1 inhibitor, we evaluated the effects of KR-32560 on cardiac function in a rat model of ischemia/reperfusion (I/R)-induced heart injury as well as the role antioxidant enzymes and pro-survival proteins play these observed effects. In isolated rat hearts subjected to 25 min of global ischemia followed by 30 min of reperfusion, KR-32560 (3 and 10 microM) significantly reversed the I/Rinduced decrease in left ventricular developed pressure and increase in left ventricular enddiastolic pressure. In rat hearts reperfused for 30 min, KR-32560 (10 microM) significantly decreased the malondialdehyde content while increasing the activities of both glutathione peroxidase and catalase, two important antioxidant enzymes. Western blotting analysis of left ventricles subjected to I/R showed that KR-32560 significantly increased phosphorylation of both Akt and GSK-3beta in a dose-dependent manner, with no effect on the phosphorylation of eNOS. These results suggest that KR-32560 exerts potent cardioprotective effects against I/Rinduced rat heart injury and that its mechanism involves antioxidant enzymes and the Akt-GSK-3beta cell survival pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12272-010-0815-zDOI Listing
August 2010

The impact of CpG island on defining transcriptional activation of the mouse L1 retrotransposable elements.

PLoS One 2010 Jun 29;5(6):e11353. Epub 2010 Jun 29.

The John Curtin School of Medical Research, Australian National University, Canberra, Australia.

Background: L1 retrotransposable elements are potent insertional mutagens responsible for the generation of genomic variation and diversification of mammalian genomes, but reliable estimates of the numbers of actively transposing L1 elements are mostly nonexistent. While the human and mouse genomes contain comparable numbers of L1 elements, several phylogenetic and L1Xplore analyses in the mouse genome suggest that 1,500-3,000 active L1 elements currently exist and that they are still expanding in the genome. Conversely, the human genome contains only 150 active L1 elements. In addition, there is a discrepancy among the nature and number of mouse L1 elements in L1Xplore and the mouse genome browser at the UCSC and in the literature. To date, the reason why a high copy number of active L1 elements exist in the mouse genome but not in the human genome is unknown, as are the potential mechanisms that are responsible for transcriptional activation of mouse L1 elements.

Methodology/principal Findings: We analyzed the promoter sequences of the 1,501 potentially active mouse L1 elements retrieved from the GenBank and L1Xplore databases and evaluated their transcription factors binding sites and CpG content. To this end, we found that a substantial number of mouse L1 elements contain altered transcription factor YY1 binding sites on their promoter sequences that are required for transcriptional initiation, suggesting that only a half of L1 elements are capable of being transcriptionally active. Furthermore, we present experimental evidence that previously unreported CpG islands exist in the promoters of the most active T(F) family of mouse L1 elements. The presence of sequence variations and polymorphisms in CpG islands of L1 promoters that arise from transition mutations indicates that CpG methylation could play a significant role in determining the activity of L1 elements in the mouse genome.

Conclusions: A comprehensive analysis of mouse L1 promoters suggests that the number of transcriptionally active elements is significantly lower than the total number of full-length copies from the three active mouse L1 families. Like human L1 elements, the CpG islands and potentially the transcription factor YY1 binding sites are likely to be required for transcriptional initiation of mouse L1 elements.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011353PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2894050PMC
June 2010

Control of chicken CR1 retrotransposons is independent of Dicer-mediated RNA interference pathway.

BMC Biol 2009 Aug 19;7:53. Epub 2009 Aug 19.

The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia.

Background: Dicer is an RNase III-ribonuclease that initiates the formation of small interfering RNAs as a defence against genomic parasites such as retrotransposons. Despite intensive characterization in mammalian species, the biological functions of Dicer in controlling retrotransposable elements of the non-mammalian vertebrate are poorly understood. In this report, we examine the role of chicken Dicer in controlling the activity of chicken CR1 retrotransposable elements in a chicken-human hybrid DT40 cell line employing a conditional loss-of-Dicer function.

Results: Retrotransposition is detrimental to host genome stability and thus eukaryotic cells have developed mechanisms to limit the expansion of retrotransposons by Dicer-mediated RNAi silencing pathways. However, the mechanisms that control the activity and copy numbers of transposable elements in chicken remain unclear. Here, we describe how the loss of Dicer in chicken cells does not reactivate endogenous chicken CR1 retrotransposons with impaired RNAi machinery, suggesting that the control of chicken CR1 is independent of Dicer-induced RNAi silencing. In contrast, upon introduction of a functionally active human L1 retrotransposable element that contains an active 5' UTR promoter, the Dicer-deficient chicken cells show a strong increase in the accumulation of human L1 transcripts and retrotransposition activity, highlighting a major difference between chicken CR1 and other mammalian L1 retrotransposons.

Conclusion: Our data provide evidence that chicken CR1 retrotransposons, unlike their mammalian L1 counterparts, do not undergo retrotransposition because most CR1 retrotransposons are truncated or mutated at their 5'UTR promoters and thus are not subjected to Dicer-mediated RNAi-silencing control.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1741-7007-7-53DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2734521PMC
August 2009

KR-31761, a novel K+(ATP)-channel opener, exerts cardioprotective effects by opening both mitochondrial K+(ATP) and Sarcolemmal K+(ATP) channels in rat models of ischemia/reperfusion-induced heart injury.

J Pharmacol Sci 2009 Feb;109(2):222-32

Department of Applied Biochemistry, Division of Life Science, College of Biomedical and Health Science, Konkuk University, Korea.

The cardioprotective effects of KR-31761, a newly synthesized K+(ATP) opener, were evaluated in rat models of ischemia/reperfusion (I/R) heart injury. In isolated rat hearts subjected to 30-min global ischemia/30-min reperfusion, KR-31761 perfused prior to ischemia significantly increased both the left ventricular developed pressure (% of predrug LVDP: 17.8, 45.1, 54.2, and 62.6 for the control, 1 microM, 3 microM, and 10 microM, respectively) and double product (DP: heart rate x LVDP; % of predrug DP: 17.5, 44.9, 56.2, and 64.5 for the control, 1 microM, 3 microM, and 10 microM, respectively) at 30-min reperfusion while decreasing the left ventricular end-diastolic pressure (LVEDP). KR-31761 (10 microM) significantly increased the time to contracture during the ischemic period, whereas it concentration-dependently decreased the lactate dehydrogenase release during reperfusion. All these parameters were significantly reversed by 5-hydroxydecanoate (5-HD, 100 microM) and glyburide (1 microM), selective and nonselective blockers of the mitochondrial K+(ATP) (mitoK+(ATP)) channel and K+(ATP) channel, respectively. In anesthetized rats subjected to 30-min occlusion of left anterior descending coronary artery/2.5-h reperfusion, KR-31761 administered 15 min before the onset of ischemia significantly decreased the infarct size (72.2%, 55.1%, and 47.1% for the control, 0.3 mg/kg, i.v., and 1.0 mg/kg, i.v., respectively); and these effects were completely and almost completely abolished by 5-HD (10 mg/kg, i.v.) and HMR-1098, a selective blocker of sarcolemmal K+(ATP) (sarcK+(ATP)) channel (6 mg/kg, i.v.) administered 5 min prior to KR-31761 (72.3% and 67.9%, respectively). KR-31761 only slightly relaxed methoxamine-precontracted rat aorta (IC50: > 30.0 microM). These results suggest that KR-31761 exerts potent cardioprotective effects through the opening of both mitoK+(ATP) and sarcK+(ATP) channels in rat hearts with a minimal vasorelaxant effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1254/jphs.08132fpDOI Listing
February 2009

Isolation and physiological characterization of Bacillus clausii SKAL-16 isolated from wastewater.

J Microbiol Biotechnol 2008 Dec;18(12):1908-14

Department of Biological Engineering, Seokyeong University, Seoul 136-704, Korea.

An alkaliphilic bacterium, Bacillus clausii SKAL-16, was isolated from soil that had been contaminated with vegetable oil. The optimal pH and general pH range for bacterial growth was 8, and 7 to 10, respectively. The bacterium could grow on tributyrin and glycerol, but could not grow on acetate and butyrate. The SKAL-16 strain excreted butyric acid during growth on tributyrin, and selectively ingested glycerol during growth on a mixture of butyric acid and glycerol. The SKAL-16 generated intracellular lipase, but did not produce esterase and extracellular lipase. The DNA fragment amplified with the chromosomal DNA of SKAL-16 and primers designed on the basis of the esterase-coding gene of Bacillus clausii KSM-K16 was not identical with the esterase-coding gene contained in the GenBank database. Pyruvate dehydrogenase, isocitrate dehydrogenase, and malate dehydrogenase activities were detected in the cellfree extract (crude enzyme).
View Article and Find Full Text PDF

Download full-text PDF

Source
December 2008

Characterization of exopolysaccharide (EPS) produced by Weissella hellenica SKkimchi3 isolated from kimchi.

J Microbiol 2008 Oct 31;46(5):535-41. Epub 2008 Oct 31.

Department of Biological Engineering, Seokyeong University, Seoul 136-704, Republic of Korea.

Weissella hellenica SKkimchi3 produces the higher exopolysaccharide (EPS) on sucrose than lactose, glucose, and fructose at pH 5 and 20 degrees C. Sucrose was exclusively used to cultivate SKkimchi3 in all experiments base on the EPS production tests. The molecular mass of EPS, as determined by gel permeation chroma-tography, was 203,000. (1)H and (13)C NMR analysis indicated that the identity of EPS may be a glucan. When EPS, starch, and cellulose was treated with a-amylase, glucoamylase, glucosidase, and cellulase, glucose was produced from starch and cellulose but was not produced from EPS. Based on HPLC analysis, elemental analysis, (1)H and (13)C NMR analysis, and enzymatic hydrolysis tests, EPS was estimated to be a glucan. EPS suspension was not precipitated even by centrifugation at 10,000xg for 60 min, and EPS made the fermented milk and bacterial culture viscous.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12275-008-0134-yDOI Listing
October 2008
-->