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1.
Niger J Clin Pract ; 27(4): 541-544, 2024 Apr 01.
Article En | MEDLINE | ID: mdl-38679780

ABSTRACT: Myotonic dystrophy (DM) is an autosomal dominant genetic disorder characterized by progressively worsening loss of muscle mass and weakness. Anesthesiologists face challenges in managing these patients due to risks such as prolonged intubation and delayed recovery associated with anesthesia in such conditions. We report a case of a 40-year-old male patient undergoing open total gastrectomy under general anesthesia. After the surgery, we administered sugammadex to reverse neuromuscular blockade and confirmed the patient's spontaneous breathing. We then proceeded to extubate the patient. However, the patient experienced complications such as apnea, desaturation, and mental changes. The patient was re-intubated and transferred to the intensive care unit for ventilator support. He was diagnosed with DM by genetic test later. Poor preoperative assessment or undiagnosed DM in surgical patients can lead to severe complications. Thus, it is important to carefully check preoperative laboratory results, patient history, and physical findings.


Anesthesia, General , Myotonic Dystrophy , Humans , Myotonic Dystrophy/diagnosis , Myotonic Dystrophy/complications , Male , Adult , Anesthesia, General/methods , Gastrectomy/methods , Sugammadex , Neuromuscular Blockade/methods
2.
Niger J Clin Pract ; 26(8): 1097-1100, 2023 Aug.
Article En | MEDLINE | ID: mdl-37635602

Backgrounds: Among various vascular access devices, midline catheters (MCs) are commonly used in emergency departments, but rarely in operating rooms. Aims: To evaluate the feasibility and safety of MCs in the operating room. Materials and Methods: This was a retrospective study. The medical records of patients who underwent MC placement in the operating room from October 2020 to July 2022 were reviewed. The rates of successful catheter insertion as well as major and minor complications were assessed. Results: Successful catheter insertions were achieved in 149 of 161 patients (92.5%). The median dwell time of midlines was eight days (IQR: 6-10 days). A major or minor complication occurred in 6.7% of the midlines. The rates of major complications of occlusion, upper extremity deep vein thrombosis (DVT), and catheter-related bloodstream infection were 1.3%, 0.7%, and 0%, respectively. Conclusions: Placement of MCs in the operating room was feasible and safe. Also, the procedure provides an acceptable alternative for replacing central line catheters and peripherally inserted central catheters.


Catheters , Operating Rooms , Humans , Retrospective Studies , Emergency Service, Hospital , Medical Records
3.
Niger J Clin Pract ; 25(5): 728-730, 2022 May.
Article En | MEDLINE | ID: mdl-35593620

The recurrence or exacerbation of phantom limb pain (PLP) induced by spinal anesthesia in patients with amputated limbs is rare, but it can occur in any amputee. A 76-year-old woman with an amputated right knee underwent three left knee surgeries with spinal anesthesia over a period of 6 months. She did not experience PLP in the previous two surgeries but experienced the recurrence of severe PLP after the third surgery for the left knee amputation. It is believed that this third operation caused the patient to experience even more severe psychological stress than the previous two operations. Regional blocks can induce PLP in amputees. In addition, PLP can be triggered and exacerbated by psychological factors. Therefore, we suggest that physicians check the patient's psychological state and provide adequate mental stability when performing surgeries with spinal anesthesia in amputated patients.


Amputees , Anesthesia, Spinal , Phantom Limb , Aged , Amputation, Surgical/adverse effects , Anesthesia, Spinal/adverse effects , Cross-Sectional Studies , Female , Humans , Phantom Limb/etiology
4.
Niger J Clin Pract ; 25(1): 85-89, 2022 Jan.
Article En | MEDLINE | ID: mdl-35046200

BACKGROUNDS: Traditionally, vascular interventions have been performed through the femoral artery. AIMS: The purpose of this study was to evaluate risk factors affecting access-site complications in patients with hepatocellular carcinoma or peripheral arterial disease in lower extremity who underwent vascular intervention by accessing the common femoral artery (CFA). PATIENTS AND METHODS: From December 2015 to November 2018, 287 patients underwent transarterial chemoembolization (TACE) or peripheral vascular intervention with ultrasound (US)-guided CFA access. Standard 18-gauge (G) access was used in 127 patients and Micropuncture® 21-G needles in 160 patients. Most access sites were managed with vascular closure devices and several were managed with manual compression. Within 24 hours after the procedure, all patients underwent US to evaluate the puncture site. RESULTS: Access-site complications occurred in 55 of 287 patients: 34 hematomas (11.9%), 20 pseudoaneurysms (7.0%), and 1 dissection (0.4%). In the crude model, risk factors related to access-site complications were the usage of 18-G needles (OR, 2.18; 95% CI, 1.17-4.07; P = 0.014), smoking (OR, 2.23; 95% CI, 1.16-4.27; P = 0.016), and approach route (OR, 3.23; 95% CI, 1.33-7.82; P = 0.009). Needle size (OR, 2.13; 95% CI, 1.10-4.12; P = 0.025) was the only factor associated with access-site complications in the adjusted model. CONCLUSION: Needle profile was the only factor associated with access-site complications in this study. Therefore, a needle with a smaller profile than an 18-G needle will reduce the incidence of complications at the access site.


Carcinoma, Hepatocellular , Catheterization, Peripheral , Chemoembolization, Therapeutic , Liver Neoplasms , Catheterization, Peripheral/adverse effects , Femoral Artery/diagnostic imaging , Femoral Artery/surgery , Humans , Retrospective Studies , Risk Factors , Treatment Outcome
5.
Anim Genet ; 48(4): 490-492, 2017 Aug.
Article En | MEDLINE | ID: mdl-28378952

Beta-defensins is a family of avian peptides related to the innate immune system. Copy number variation was recently reported for the avian beta-defensin 7 gene (AvBD7) between the highly inbred Leghorn and Fayoumi lines. Here, we examined copy number variants in 35 different chicken breeds and found that 31 of them have at least the same representation of the duplicated AvBD7 allele. We also found haplotypes upstream of the AvBD6 regions that are strongly linked to the AvBD7 duplication. We observed a strong linkage disequilibrium spanning of the upstream region of the AvBD6 gene, with two SNPs being flanking markers to detect duplication of the AvBD7.


Chickens/genetics , DNA Copy Number Variations , Gene Duplication , Haplotypes , beta-Defensins/genetics , Animals , Breeding , Linkage Disequilibrium , Multigene Family , Polymorphism, Single Nucleotide
6.
J Periodontal Res ; 52(3): 617-627, 2017 Jun.
Article En | MEDLINE | ID: mdl-28198538

BACKGROUND: Although expression of peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (PIN1) was reported in bone tissue, the precise role of PIN1 in periodontal tissue and cells remain unclear. MATERIAL & METHODS: To elucidate the roles of PIN1 in periodontal tissue, its expression in periodontal tissue and cells, and effects on in vitro 4 osteoblast differentiation and the underlying signaling mechanisms were evaluated. RESULTS: PIN1 was expressed in mouse periodontal tissues including periodontal ligament cells (PDLCs), cementoblasts and osteoblasts at the developing root formation stage (postnatal, PN14) and functional stage of tooth (PN28). Treatment of PIN1 inhibitor juglone, and gene silencing by RNA interference promoted osteoblast differentiation in PDLCs and cementoblasts, whereas the overexpression of PIN1 inhibited. Moreover, osteogenic medium-induced activation of AMPK, mTOR, Akt, ERK, p38 and NF-jB pathways were enhanced by PIN1 siRNA, but attenuated by PIN1 overexpression. Runx2 expressions were induced by PIN1 siRNA, but downregulated by PIN1 overexpression. CONCLUSION: In summary, this study is the first to demonstrate that PIN1 is expressed in developing periodontal tissue, and in vitro PDLCs and cementoblasts. PIN1 inhibition stimulates osteoblast differentiation, and thus may play an important role in periodontal regeneration.


NIMA-Interacting Peptidylprolyl Isomerase/physiology , Periodontium/metabolism , Animals , Cell Differentiation , Dental Cementum/metabolism , In Vitro Techniques , Mice , NIMA-Interacting Peptidylprolyl Isomerase/metabolism , Osteoblasts/metabolism , Periodontal Ligament/metabolism , Periodontium/cytology
7.
Neuropathol Appl Neurobiol ; 43(7): 584-603, 2017 Dec.
Article En | MEDLINE | ID: mdl-28235153

AIMS: The leucine-rich repeat kinase 2 (LRRK2) G2019S mutation is the most common genetic cause of Parkinson's disease (PD). There is compelling evidence that PD is not only a brain disease but also a gastrointestinal disorder; nonetheless, its pathogenesis remains unclear. We aimed to develop human neural and intestinal tissue models of PD patients harbouring an LRRK2 mutation to understand the link between LRRK2 and PD pathology by investigating the gene expression signature. METHODS: We generated PD patient-specific induced pluripotent stem cells (iPSCs) carrying an LRRK2 G2019S mutation (LK2GS) and then differentiated into three-dimensional (3D) human neuroectodermal spheres (hNESs) and human intestinal organoids (hIOs). To unravel the gene and signalling networks associated with LK2GS, we analysed differentially expressed genes in the microarray data by functional clustering, gene ontology (GO) and pathway analyses. RESULTS: The expression profiles of LK2GS were distinct from those of wild-type controls in hNESs and hIOs. The most represented GO biological process in hNESs and hIOs was synaptic transmission, specifically synaptic vesicle trafficking, some defects of which are known to be related to PD. The results were further validated in four independent PD-specific hNESs and hIOs by microarray and qRT-PCR analysis. CONCLUSION: We provide the first evidence that LK2GS also causes significant changes in gene expression in the intestinal cells. These hNES and hIO models from the same genetic background of PD patients could be invaluable resources for understanding PD pathophysiology and for advancing the complexity of in vitro models with 3D expandable organoids.


Induced Pluripotent Stem Cells/metabolism , Intestinal Mucosa/metabolism , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics , Neurons/metabolism , Organoids/metabolism , Parkinson Disease/genetics , Adult , Cell Differentiation , Female , Gene Expression , Gene Ontology , Genome , Humans , Induced Pluripotent Stem Cells/cytology , Induced Pluripotent Stem Cells/physiology , Intestines/cytology , Male , Middle Aged , Mutation , Neurons/cytology , Organoids/cytology
8.
Anim Genet ; 48(2): 225-227, 2017 Apr.
Article En | MEDLINE | ID: mdl-27925267

In contrast to a single copy of the NK-lysin gene in humans and many other mammals, we previously identified a family of four expressed NK-lysin genes arising by tandem duplications on cattle chromosome 11. Here, we report two genetic variants in the bovine NK-lysin complex with potential importance in the bovine innate immune system. The first one is a 9-bp deletion causing a three-amino-acid deletion in the pro-region of the NK1 gene product. The second is a deletion of NK2B in some Holstein cattle, resulting in copy number variation that is in disequilibrium with a SNP from the bovine 770K HD SNP array. We also show evidence for gene conversions within the three new NK2 genes, which at least partially accounts for their high degree of sequence identity.


Cattle/genetics , Genetic Variation , Proteolipids/genetics , Animals , DNA Copy Number Variations , Evolution, Molecular , Gene Conversion , Polymorphism, Single Nucleotide
9.
Oncogene ; 35(41): 5435-5445, 2016 10 13.
Article En | MEDLINE | ID: mdl-27041572

Hepatitis B virus X protein (HBx) contributes to the development of hepatocellular carcinoma (HCC), probably by regulating activities of many host or viral proteins through protein-protein interactions. In this study, we identified poly(ADP-ribose) polymerase (PARP1), a crucial factor in DNA repair, as an HBx-interacting protein using a proteomics approach. Coimmunoprecipitation and proximity ligation assays confirmed the binding and colocalization of HBx and PARP1 in the nucleus. The carboxyl-terminus of HBx protein bound to the catalytic domain of PARP1, and this binding reduced the enzymatic activity of PARP1 in both in vitro and in vivo assays. HBx interrupted the binding of PARP1 to Sirt6, which catalyzes the mono-ADP-ribosylation required for DNA repair. Consistently, overexpression of HBx inhibited the clearance of γH2AX DNA repair foci generated under oxidative stress in Chang liver cells. Recruitment of the DNA repair complex to the site-specific double-strand breaks was inhibited in the presence of HBx, when measured by laser microirradiation assay and damage-specific chromatin immunoprecipitation assays. Consequently, HBx increased signs of DNA damage such as accumulation of 8-hydroxy-2'-deoxyguanosine and comet formation, which were reversed by overexpression of PARP1 and/or Sirt6. Finally, the interaction between PARP1 and Sirt6 was markedly lower in the livers of HBx-transgenic mice and specimens obtained from HCC patients to compare with the corresponding control. Our data suggest that the physical interaction of HBx and PARP1 accelerates DNA damage by inhibiting recruitment of the DNA repair complex to the damaged DNA sites, which may lead to the onset of hepatocarcinogenesis.


Carcinoma, Hepatocellular/genetics , Liver Neoplasms/genetics , Poly (ADP-Ribose) Polymerase-1/genetics , Sirtuins/genetics , Trans-Activators/genetics , Animals , Carcinogenesis/genetics , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/virology , DNA Damage/genetics , DNA Repair/genetics , DNA-Binding Proteins/genetics , Gene Expression Regulation, Neoplastic , Hep G2 Cells , Hepatitis B virus/genetics , Hepatitis B virus/pathogenicity , Histones/genetics , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/pathology , Liver Neoplasms/virology , Mice , Mice, Transgenic , Poly (ADP-Ribose) Polymerase-1/metabolism , Sirtuins/metabolism , Trans-Activators/metabolism , Viral Regulatory and Accessory Proteins
11.
Poult Sci ; 92(3): 760-9, 2013 Mar.
Article En | MEDLINE | ID: mdl-23436527

The basic functions of DNA methylation include in gene silencing by methylation of specific gene promoters, defense of the host genome from retrovirus, and transcriptional suppression of transgenes. In addition, genomic imprinting, by which certain genes are expressed in a parent-of-origin-specific manner, has been observed in a wide range of plants and animals and has been associated with differential methylation. However, imprinting phenomena of DNA methylation effects have not been revealed in chickens. To analyze whether genomic imprinting occurs in chickens, methyl-DNA immunoprecipitation array analysis was applied across the entire genome of germ cells in early chick embryos. A differentially methylated region (DMR) was detected in the eighth intron of the l-arginine:glycine amidinotransferase (GATM) gene. When the DMR in GATM was analyzed by bisulfite sequencing, the methylation in male primordial germ cells (PGC) of 6-d-old embryos was higher than that in female PGC (57.5 vs. 35.0%). At 8 d, the DMR methylation of GATM in male PGC was 3.7-fold higher than that in female PGC (65.0 vs. 17.5%). Subsequently, to investigate mono- or biallelic expression of the GATM gene during embryo development, we found 2 indel sequences (GTTTAATGC and CAAAAA) within the GATM 3'-untranslated region in Korean Oge (KO) and White Leghorn (WL) chickens. When individual WL and KO chickens were genotyped for indel sequences, 3 allele combinations (homozygous insertion, homozygous deletion, and heterozygotes) were detected in both breeds using a gel shift assay and high-resolution melt assay. The deletion allele was predominant in KO, whereas the insertion allele was predominant in WL. Heterozygous animals were evenly distributed in both breeds (P < 0.01). Despite the different methylation status between male and female PGC, the GATM gene conclusively displayed biallelic expression in PGC as well as somatic embryonic, extraembryonic, and adult chicken tissues.


Amidinotransferases/metabolism , Chickens , DNA Methylation , Gene Expression Regulation/physiology , Germ Cells/metabolism , Alleles , Amidinotransferases/genetics , Animals , Base Sequence , Female , Genotype , Male , Molecular Sequence Data
12.
Oncogene ; 31(49): 5099-107, 2012 Dec 06.
Article En | MEDLINE | ID: mdl-22286760

The metastasis-associated protein 1 (MTA1) is overexpressed in various human cancers and is closely connected with aggressive phenotypes; however, little is known about the transcriptional regulation of the MTA1 gene. This study identified the MTA1 gene as a target of p53-mediated transrepression. The MTA1 promoter contains two putative p53 response elements (p53REs), which were repressed by the p53-inducing drug 5-fluorouracil (5-FU). Notably, 5-FU treatment decreased MTA1 expression only in p53 wild-type cells. p53 and histone deacetylases 1/2 were recruited, and acetylation of H3K9 was decreased on the promoter region including the p53REs after 5-FU treatment. Proteomics analysis of the p53 repressor complex, which was pulled down by the MTA1 promoter, revealed that the poly(ADP-ribose) polymerase 1 (PARP-1) was part of the complex. Interestingly, p53 was poly(ADP-ribose)ylated by PARP-1, and the p53-mediated transrepression of the MTA1 gene required poly(ADP-ribose)ylation of p53. In summary, we report a novel function for poly(ADP-ribose)ylation of p53 in the gene-specific regulation of the transcriptional mode of p53 on the promoter of MTA1.


Histone Deacetylases/genetics , Poly Adenosine Diphosphate Ribose/metabolism , Repressor Proteins/genetics , Tumor Suppressor Protein p53/metabolism , Animals , Cell Line , Fibroblasts/metabolism , Fluorouracil/pharmacology , Gene Expression Regulation , Histone Deacetylase 1/genetics , Histone Deacetylase 1/metabolism , Histone Deacetylase 2/genetics , Histone Deacetylase 2/metabolism , Histone Deacetylases/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , MCF-7 Cells/drug effects , Mice , Poly (ADP-Ribose) Polymerase-1 , Poly(ADP-ribose) Polymerases/genetics , Poly(ADP-ribose) Polymerases/metabolism , Promoter Regions, Genetic/drug effects , Repressor Proteins/metabolism , Response Elements , Trans-Activators , Tumor Suppressor Protein p53/genetics
13.
Oncogenesis ; 1: e25, 2012 Sep 03.
Article En | MEDLINE | ID: mdl-23552838

Expression of metastasis-associated protein 1 (MTA1) gene correlates with the degree of invasion and metastasis in hepatocellular carcinoma (HCC). Expression of MTA1 is induced by hepatitis B virus X protein (HBx); however, little is known about the transcriptional regulation of MTA1 gene expression. Here, we report that the 5'-flanking region of the human MTA1 promoter contains two CpG islands. Transient expression of HBx in Chang liver cells increased the methylation of the CpG island1 from 18 to 49% when measured by bisulfite-modified direct sequencing. Chromatin immunoprecipitation showed that HBx recruited DNA methyltransferase 3a (DNMT3a) and DNMT3b to the CpG island1. In silico analysis of CpG island1 predicted the existence of putative p53-binding sequences. p53 was pulled down by a DNA probe encoding the p53-binding sequences but not by the methylated DNA probe. The mouse MTA1 promoter also contains a CpG island encoding a p53-binding sequence of which p53 binding was decreased in the presence of HBx, and the expression of MTA1 and DNMT3 was increased in the liver of HBx-transgenic mice. Comparison of MTA1 and DNMT3a expression in the human normal liver and HCC specimens produced a significant correlation coefficient >0.5 (r=0.5686, P=0.0001) for DNMT3a, and a marginally significant coefficient (r=0.3162, P=0.0103) for DNMT3b. These data show that HBx induces methylation of CpG island in the MTA1 promoter, which interferes with DNA binding of p53 in the specific DNA region. This result may explain the molecular mechanism responsible for the induction of MTA1 gene expression by HBx.

14.
Cell Mol Neurobiol ; 31(1): 93-9, 2011 Jan.
Article En | MEDLINE | ID: mdl-21061168

Iron is essential for normal brain function and its uptake in the developing rat brain peaks during the first two weeks after birth, prior to the formation of the blood­brain barrier (BBB). The first step of iron transport from the blood to the brain is transferrin receptor (TfR)-mediated endocytosis in the capillary endothelial cells. However, the subsequent step from the endothelium into interstitium has not been fully described. The goal of this study was to examine the expression of iron transport proteins by immunodetection and RT­PCR in the developing rat brain. Tf and TfR are transiently expressed in perivascular NG2+ cells of the capillary wall during the early postnatal weeks in the rat brain. However, MTP-1 and hephaestin were expressed in endothelial cells, but not in the NG2+ perivascular cells. Immunoblot analysis for these iron transfer proteins in the developing brain generally confirmed the immunochemical findings. Furthermore, the expression of Tf and TfR in the blood vessels precedes its expression in oligodendrocytes, the main iron-storing cells in the vertebrate brain. RT­PCR analysis for the primary culture of endothelial cells and pericytes revealed that Tf and TfR were highly expressed in the pericytes while MTP-1 and hephaestin were expressed in the endothelial cells. The specific expression of Tf and TfR in brain perivascular cells and MTP-1 and hephaestin in endothelial cells suggest the possibility that trafficking of elemental iron through perivascular cells may be instrumental in the distribution of iron in the developing central nervous system.


Brain/blood supply , Brain/growth & development , Brain/metabolism , Capillaries/metabolism , Carrier Proteins/genetics , Iron/metabolism , Animals , Animals, Newborn , Blood-Brain Barrier/metabolism , Carrier Proteins/metabolism , Cation Transport Proteins/genetics , Cation Transport Proteins/metabolism , Cells, Cultured , Endothelial Cells/metabolism , Gene Expression Regulation, Developmental , Ion Transport/genetics , Membrane Proteins/genetics , Membrane Proteins/metabolism , Rats , Rats, Sprague-Dawley , Receptors, Transferrin/genetics , Receptors, Transferrin/metabolism , Time Factors , Transferrin/genetics , Transferrin/metabolism
15.
Oncogene ; 27(24): 3405-13, 2008 May 29.
Article En | MEDLINE | ID: mdl-18264140

Expression level of metastasis-associated protein 1 (MTA1) is closely related to tumor growth and metastasis in various cancers. Although increased expression level of MTA1 was observed in hepatocellular carcinoma (HCC), role of MTA1 complex containing histone deacetylase (HDAC) in hepatitis B virus (HBV)-associated hepatocarcinogenesis has not been studied. Here, we demonstrated that HBx strongly induced the expression of MTA1 and HDAC1 genes at transcription level. MTA1 and HDAC1/2 physically associated with hypoxia-inducible factor-1 alpha (HIF-1 alpha) in vivo in the presence of HBx, which was abolished by knockdown of MTA1 by short interfering RNA (siRNA). HBx induced deacetylation of the oxygen-dependent degradation domain of HIF-1 alpha, which was accompanied with dissociation of prolyl hydroxylases and von Hippel-Lindau tumor suppressor from HIF-1 alpha. These results indicate that HBx-induced deacetylation is important for proteasomal degradation of HIF-1 alpha. Further, we observed that protein levels of MTA1 and HDAC1 were increased in the liver of HBx-transgenic mice. Also, there was a higher expression of HDAC1 in HCC than in the adjacent non-tumorous cirrhotic nodules in 10 out of 12 human HBV-associated HCC specimens. Together, our data indicate a positive cross talk between HBx and the MTA1/HDAC complex in stabilizing HIF-1 alpha, which may play a critical role in angiogenesis and metastasis of HBV-associated HCC.


Carcinoma, Hepatocellular/metabolism , Cell Hypoxia , Histone Deacetylases/genetics , Repressor Proteins/genetics , Trans-Activators/physiology , Transcription Factors/genetics , Acetylation , Animals , Blotting, Western , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/virology , Gene Expression , Histone Deacetylase 1 , Histone Deacetylase 2 , Histone Deacetylases/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Immunoenzyme Techniques , Immunoprecipitation , Liver/metabolism , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Liver Neoplasms/virology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Repressor Proteins/metabolism , Retrospective Studies , Signal Transduction , Transcription Factors/metabolism , Tumor Cells, Cultured , Viral Regulatory and Accessory Proteins
16.
Oncogene ; 26(26): 3823-34, 2007 May 31.
Article En | MEDLINE | ID: mdl-17146432

Hypoxia-inducible factor-1alpha (HIF-1alpha) plays a central role in oxygen homeostasis. Previously, we reported that the orphan nuclear receptor Nur77 functions in stabilizing HIF-1alpha. Here, we demonstrate that 6-mercaptopurine (6-MP), an activator of the NR4A family members, enhances transcriptional activity of HIF-1. 6-MP enhanced the protein-level of HIF-1alpha as well as vascular endothelial growth factor (VEGF) in a dose- and time-dependent manner. The induction of HIF-1alpha was abolished by the transfection of either a dominant-negative Nur77 mutant or si-Nur77, indicating a critical role of Nur77 in the 6-MP action. The HIF-1alpha protein level remained up to 60 min in the presence of 6-MP when de novo protein synthesis was blocked by cycloheximide, suggesting that 6-MP induces stabilization of the HIF-1alpha protein. The fact that 6-MP decreased the association of HIF-1alpha with von Hippel-Lindau protein and the acetylation of HIF-1alpha, may explain how 6-MP induced stability of HIF-1alpha. Further, 6-MP induced the transactivation function of HIF-1alpha by recruiting co-activator cyclic-AMP-response-element-binding protein. Finally, 6-MP enhanced the expression of HIF-1alpha and VEGF, and the formation of capillary tubes in human umbilical vascular endothelial cells. Together, our results provide a new insight for 6-MP action in the stabilization of HIF-1alpha and imply a potential application of 6-MP in hypoxia-associated human vascular diseases.


DNA-Binding Proteins/drug effects , Hypoxia-Inducible Factor 1, alpha Subunit/drug effects , Immunosuppressive Agents/pharmacology , Mercaptopurine/pharmacology , Neovascularization, Physiologic/drug effects , Receptors, Cytoplasmic and Nuclear/drug effects , Receptors, Steroid/drug effects , Transcription Factors/drug effects , Cell Line, Tumor , DNA-Binding Proteins/metabolism , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Nuclear Receptor Subfamily 4, Group A, Member 1 , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, Steroid/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factors/metabolism , Transcription, Genetic , Transfection , Vascular Endothelial Growth Factor A/drug effects , Vascular Endothelial Growth Factor A/metabolism
17.
Endocrinology ; 142(12): 5116-23, 2001 Dec.
Article En | MEDLINE | ID: mdl-11713204

The orphan nuclear receptor Nur77 (NR4A1) is a member of the nuclear receptor superfamily and plays an important role in the regulation of genes involved in steroidogenesis and cell death. Northern blot analysis revealed that the expression of Nur77 mRNA was increased after puberty in mouse testis, and hCG treatment of peripubertal animals induced this gene expression in the testis. Moreover, LH treatment induced a transient increase in Nur77 mRNA, and this induction was LH dose dependent in mouse Leydig tumor cell line, K28. Western blot analysis showed that LH transiently induced Nur77 protein. The protein kinase inhibitor H-89, bisindolymaleimide I, and wortmannin strongly inhibited this inductive effect of LH on Nur77 gene expression. Transient transfection assay demonstrated that LH significantly increased the Nur77 promoter-driven luciferase reporter activity in a dose-dependent manner, and LH also increased the activity of a luciferase reporter gene driven by a promoter containing multi copies of a Nur77-responsive element. Moreover, EMSA showed that Nur77 DNA-binding activity was increased in response to LH. Finally, overexpression of dominant negative Nur77 reduced LH-mediated progesterone biosynthesis. Taken together, these results demonstrate that LH induces Nur77 gene expression, and Nur77 may play an important role in the LH-mediated steroidogenesis in Leydig cells.


DNA-Binding Proteins/genetics , Gene Expression/physiology , Leydig Cells/physiology , Luteinizing Hormone/physiology , Transcription Factors/genetics , Animals , Cell Line , DNA/metabolism , Dose-Response Relationship, Drug , Gene Expression/drug effects , Leydig Cells/metabolism , Luteinizing Hormone/pharmacology , Male , Mice , Nuclear Receptor Subfamily 4, Group A, Member 1 , Promoter Regions, Genetic/physiology , Receptors, Cytoplasmic and Nuclear , Receptors, Steroid , Signal Transduction/physiology , Steroids/biosynthesis , Testis/growth & development , Time Factors
18.
Biochem Biophys Res Commun ; 288(5): 1162-8, 2001 Nov 16.
Article En | MEDLINE | ID: mdl-11700033

Hepatitis B virus (HBV) X protein (HBx) plays an essential role in development of HBV-associated hepatocellular carcinoma (HCC). Recently, we reported that HBx induces Fas Ligand (FasL) expression, which may help HCC cells to evade host-immune surveillance. The aim of this study was to investigate the role of HBx in expression of Nur77, an orphan nuclear receptor implicated in the upregulation of FasL. When Chang X-34 expressing HBx under the control of a doxycycline-inducible promoter was examined, induction of Nur77 was observed following HBx expression. Blocking of Nur77 function by introduction of an antisense or a dominant negative mutant Nur77 significantly inhibited the induction of FasL, indicating that Nur77 plays critical roles in FasL expression. Further, a high-level expression of transcripts and DNA binding of Nur77 were observed in the HBV-integrated cell lines established from HCC patients that express HBx. These results suggested that Nur77 may contribute to leading the HBx-induced Fas/FasL signaling pathway which eliminates invading Fas-expressing lymphocytes.


Carcinoma, Hepatocellular/metabolism , DNA-Binding Proteins/biosynthesis , Hepatitis B/metabolism , Liver Neoplasms/metabolism , Trans-Activators/pharmacology , Transcription Factors/biosynthesis , Transcriptional Activation , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/virology , DNA-Binding Proteins/genetics , DNA-Binding Proteins/physiology , Fas Ligand Protein , Hepatitis B/genetics , Hepatitis B/virology , Hepatitis B virus/genetics , Humans , Liver Neoplasms/genetics , Liver Neoplasms/virology , Membrane Glycoproteins/biosynthesis , Membrane Glycoproteins/genetics , Mutation , Nuclear Receptor Subfamily 4, Group A, Member 1 , Oligonucleotides, Antisense/pharmacology , Promoter Regions, Genetic , RNA, Messenger/biosynthesis , Receptors, Cytoplasmic and Nuclear , Receptors, Steroid , Trans-Activators/biosynthesis , Trans-Activators/genetics , Trans-Activators/metabolism , Trans-Activators/physiology , Transcription Factors/genetics , Transcription Factors/physiology , Transfection , Tumor Cells, Cultured , Viral Regulatory and Accessory Proteins , Virus Integration
19.
Exp Cell Res ; 256(2): 545-54, 2000 May 01.
Article En | MEDLINE | ID: mdl-10772826

Nur77 (NGFI-B) is an orphan nuclear receptor that has been implicated in activation-induced T-cell apoptosis. Retinoids, potent immune modulators, were shown to inhibit the activation-induced apoptosis of immature thymocytes and T-cell hybridomas. To illustrate the mechanism of the inhibition, we examined the effects of retinoic acid (RA) on the expression and transactivation functions of Nur77 in the human peripheral blood mononuclear cells and the human T-cell leukemia, Jurkat. All-trans-RA remarkably repressed the DNA binding and transcriptional induction of Nur77. Among the two potential trans-acting factors that activate Nur77 gene promoter, i.e., AP-1 and related serum response factor (RSRF), all-trans-RA repressed DNA binding and reporter gene activity of AP-1 but not that of RSRF, suggesting that the inhibition may be mediated through AP-1. We also demonstrated a posttranscriptional regulation of Nur77 function by retinoid receptors by showing that transactivation activity of Nur77 was significantly inhibited by cotransfection of RARalpha or RXRalpha. Nur77 bound RARalpha or RXRalpha in both yeast and mammalian two-hybrid tests, suggesting that direct protein-protein interaction between these receptors may mediate the inhibition. Taken all together, we demonstrated that RA repressed Nur77 function through multiple mechanisms that may provide the basis for RA inhibition on the apoptosis of activated T-lymphocytes.


Apoptosis/physiology , DNA-Binding Proteins/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Receptors, Retinoic Acid/physiology , T-Lymphocytes/cytology , Transcription Factors/metabolism , Tretinoin/physiology , Amino Acid Motifs , DNA/metabolism , Humans , Jurkat Cells , Nuclear Receptor Subfamily 4, Group A, Member 1 , Protein Binding , Receptors, Retinoic Acid/metabolism , Receptors, Steroid , Transfection , Tretinoin/metabolism , Tretinoin/pharmacology , Two-Hybrid System Techniques
20.
Biol Pharm Bull ; 23(4): 420-6, 2000 Apr.
Article En | MEDLINE | ID: mdl-10784420

Tumor necrosis factor alpha (TNFalpha) generates a potent cytotoxic effect, however many cancer cells are resistant to TNFalpha-mediated killing and the cause of the differential sensitivity remains to be elucidated. In this study, we demonstrated that TNFalpha induced cell death in four different human colon cancer cell lines. The degree of cytotoxic effect was different in each cell line, in that HCT-15 was relatively sensitive, while DLD-1, HT-29 and WiDr were relatively resistant. TNFalpha induced apoptotic changes such as morphological changes, DNA fragmentation and activation of caspase-3 in HCT-15, but to a lesser degree in the others. Transcriptional expression of TNFR1(p55), as well as that of FLICE, Fas, FADD, DR3, FAF, TRADD, and RIP was similar in these cell lines, indicating that the susceptibility to TNFalpha-induced apoptosis may not be determined by the constitutive expression level of these factors. Interestingly, the cytotoxic effect of TNFalpha was well correlated with the DNA binding activity of NF-kappaB in the colon cancer cell lines. Further, the overexpression of a non-phosphorylated mutant form of IkappaBalpha enhanced the cytotoxicity of TNFalpha in the resistant cell line, DLD-1, indicating that NF-kappaB activity may determine the sensitivity of colon cancer cells to TNFalpha-induced apoptosis. Thus, our results indicate that modulation of NF-kappaB activity may provide a useful tool to sensitize colon cancer cells to TNFalpha treatment.


Apoptosis/drug effects , Colonic Neoplasms/pathology , I-kappa B Proteins , NF-kappa B/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Apoptosis/genetics , Base Sequence , Colonic Neoplasms/metabolism , DNA Primers , DNA-Binding Proteins/genetics , Humans , Mutation , NF-KappaB Inhibitor alpha , Tumor Cells, Cultured
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