RESUMEN
African swine fever (ASF) is a contagious and deadly viral disease affecting swine of all ages. ASF was first reported in Vietnam in February 2019, and it is now considered endemic in Vietnam. In this study, 122 ASF-positive samples collected from domestic pigs in 28 different provinces of northern, central, and southern Vietnam during outbreaks in 2019-2021 were genetically characterized. The findings confirmed that all ASF virus (ASFV) strains circulating in Vietnam belonged to p72 genotype II, p54 genotype II, CD2v serogroup 8, and CVR gene variant type I. However, further analysis based on the tandem repeat sequences located between I73R and I329L genes revealed that there were three different variants of ASFV, IGR I, II, and III, circulating in the domestic pig population in Vietnam. The IGR II variants were the most prevalent (117/122 strains) and were detected in pigs in all of the provinces tested, followed by IGR III (4/122 strains) and IGR I (1/122 strains). This study confirms for the first time the presence of IGR III variants in Vietnam.
Asunto(s)
Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Fiebre Porcina Africana/epidemiología , Virus de la Fiebre Porcina Africana/genética , Animales , Brotes de Enfermedades , Genotipo , Filogenia , Análisis de Secuencia de ADN , Sus scrofa , Porcinos , Vietnam/epidemiologíaRESUMEN
Cysteine plays a crucial role in cellular functions and in human pathologies. However, the development of cysteine probes with extremely accurate detection is still a key challenge for the field. Herein, we have fully characterized and developed a novel selective fluorescent probe: red emission, aqueous detection and large Stokes' shift for cysteine (Reals-C). Key in the probe synthesis is a Michael addition onto an acroylate group and subsequent intramolecular cyclization. The probe exhibits analyte detection via an intricate role set up by the leaving groups so to discriminate and form the red-emissive analyte sensing platform (λex =471â nm, λem =637â nm) through a chemical cascade pathway. Furthermore, the sensing ability of the probe was demonstrated by both in vitro and in vivo assays. This probe enables for successfully endogenous cysteine sensing in HaCaT human keratinocytes through comparison with a commercial thiol-sensitive probe; Reals-C shows excellent in vivo cysteine detection in a drug-induced animal liver injury model.
Asunto(s)
Cisteína/análisis , Colorantes Fluorescentes/química , Animales , Enfermedad Hepática Inducida por Sustancias y Drogas , Ciclización , Cisteína/química , Cisteína/metabolismo , Modelos Animales de Enfermedad , Colorantes Fluorescentes/síntesis química , Humanos , Queratinocitos/efectos de los fármacos , Espectrometría de Fluorescencia/métodos , Compuestos de Sulfhidrilo/químicaRESUMEN
Gomisin N is a physiological substance derived from Schisandra chinensis. In the present study, the in vitro and in vivo effects of gomisin N on endoplasmic reticulum (ER) stress and hepatic steatosis were investigated. We quantified the expression of markers of ER stress, including glucose regulated protein 78 (GRP78), CCAAT/enhancer binding protein (C/EBP) homolog protein (CHOP), and X-box-binding protein-1 (XBP-1), and triglyceride (TG) accumulation, in HepG2 cells treated with tunicamycin or palmitate. Tunicamycin treatment in HepG2 cells induced expression of markers of ER stress and increased TG levels; Gomisin N reversed these effects, reducing the expression of markers of ER stress and TG levels. Similar effects were seen following palmitate pretreatment of HepG2 cells. The inhibitory effects of gomisin N were further confirmed in mice injected with tunicamycin. Gomisin N reduced expression of markers of ER stress and decreased TG levels in mouse liver after tunicamycin injection. Furthermore, gomisin N decreased expression of inflammatory and lipogenic genes in palmitate-incubated HepG2 cells. These results suggest that gomisin N inhibits ER stress and ameliorates hepatic steatosis induced by ER stress.
Asunto(s)
Estrés del Retículo Endoplásmico/efectos de los fármacos , Hígado Graso/tratamiento farmacológico , Lignanos/uso terapéutico , Compuestos Policíclicos/uso terapéutico , Sustancias Protectoras/uso terapéutico , Acetil-CoA Carboxilasa/genética , Animales , Ciclooctanos/farmacología , Ciclooctanos/uso terapéutico , Citocinas/genética , Chaperón BiP del Retículo Endoplásmico , Acido Graso Sintasa Tipo I/genética , Hígado Graso/inducido químicamente , Hígado Graso/metabolismo , Glicerol-3-Fosfato O-Aciltransferasa/genética , Proteínas de Choque Térmico/metabolismo , Células Hep G2 , Humanos , Lignanos/farmacología , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones Endogámicos C57BL , Ácido Palmítico , Compuestos Policíclicos/farmacología , Sustancias Protectoras/farmacología , Factor de Transcripción CHOP/metabolismo , Triglicéridos/metabolismo , Tunicamicina , Proteína 1 de Unión a la X-Box/metabolismoRESUMEN
Previously, we reported that activating transcription factor 3 (ATF3) downregulates peroxisome proliferator activated receptor (PPARγ) gene expression and inhibits adipocyte differentiation in 3T3-L1 cells. Here, we investigated another role of ATF3 on the regulation of PPARγ activity. ATF3 inhibited PPARγ-stimulated transactivation of PPARγ responsive element (PPRE)-containing reporter or GAL4/PPARγ chimeric reporter. Thus, ATF3 effectively repressed rosiglitazone-stimulated expression of adipocyte fatty acid binding protein (aP2), PPARγ target gene, in 3T3-L1 cells. Coimmunoprecipitation and GST pulldown assay demonstrated that ATF3 interacted with PPARγ. Accordingly, ATF3 prevented PPARγ from binding to PPRE on the aP2 promoter. Furthermore, ATF3 suppressed p300-mediated transcriptional coactivation of PPRE-containing reporter. Chromatin immunoprecipitation assay showed that overexpression of ATF3 blocked both binding of PPARγ and recruitment of p300 to PPRE on aP2 promoter induced by rosiglitazone treatment in 3T3-L1 cells. Taken together, these results suggest that ATF3 interacts with PPARγ and represses PPARγ-mediated transactivation through suppression of p300-stimulated coactivation in 3T3-L1 cells, which may play a role in inhibition of adipocyte differentiation.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Adipocitos/citología , PPAR gamma/metabolismo , Células 3T3-L1 , Animales , Diferenciación Celular , Inmunoprecipitación de Cromatina , Proteínas de Unión a Ácidos Grasos/metabolismo , Genes Reporteros , Resistencia a la Insulina , Ratones , Regiones Promotoras Genéticas , Unión Proteica , Rosiglitazona , Tiazolidinedionas/química , Activación Transcripcional , Factores de Transcripción p300-CBP/metabolismoRESUMEN
Endoplasmic reticulum (ER) stress is associated with the pathogenesis of hepatic steatosis. Alisma orientale Juzepzuk is a traditional medicinal herb for diuretics, diabetes, hepatitis, and inflammation. In this study, we investigated the protective effects of methanol extract of the tuber of Alisma orientale (MEAO) against ER stress-induced hepatic steatosis in vitro and in vivo. MEAO inhibited the tunicamycin-induced increase in luciferase activity of ER stress-reporter constructs containing ER stress response element and ATF6 response element. MEAO significantly inhibited tunicamycin-induced ER stress marker expression including GRP78, CHOP, and XBP-1 in tunicamycin-treated Human hepatocellular carcinoma (HepG2) cells and the livers of tunicamycin-injected mice. It also inhibited tunicamycin-induced accumulation of cellular triglyceride. Similar observations were made under physiological ER stress conditions such as in palmitate (PA)-treated HepG2 cells and the livers of high-fat diet (HFD)-induced obese mice. MEAO repressed hepatic lipogenic gene expression in PA-treated HepG2 cells and the livers of HFD obese mice. Furthermore, MEAO repressed very low-density lipoprotein receptor (VLDLR) expression and improved ApoB secretion in the livers of tunicamycin-injected mice or HFD obese mice as well as in tunicamycin or PA-treated HepG2 cells. Alismol, a guaiane-type sesquiterpenes in Alisma orientale, inhibited GRP78 expression in tunicamycin-treated HepG2 cells. In conclusion, MEAO attenuates ER stress and prevents hepatic steatosis pathogenesis via inhibition of expression of the hepatic lipogenic genes and VLDLR, and enhancement of ApoB secretion.
Asunto(s)
Alisma/química , Estrés del Retículo Endoplásmico/efectos de los fármacos , Hígado Graso/metabolismo , Extractos Vegetales/farmacología , Animales , Apolipoproteínas B/metabolismo , Supervivencia Celular/efectos de los fármacos , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Chaperón BiP del Retículo Endoplásmico , Hígado Graso/tratamiento farmacológico , Hígado Graso/patología , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Células Hep G2 , Humanos , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Ratones , Ratones Obesos , Sustancias Protectoras/farmacología , Receptores de LDL/genética , Receptores de LDL/metabolismo , Triglicéridos/metabolismo , Tunicamicina/efectos adversosRESUMEN
Activating transcription factor 3 (ATF3) is a stress-adaptive transcription factor that mediates cellular stress response signaling. We previously reported that ATF3 represses CCAAT/enhancer binding protein α (C/EBPα) expression and inhibits 3T3-L1 adipocyte differentiation. In this study, we explored potential role of ATF3 in negatively regulating peroxisome proliferator activated receptor-γ (PPARγ). ATF3 decreased the expression of PPARγ and its target gene in 3T3-L1 adipocytes. ATF3 also repressed the activity of -2.6Kb promoter of mouse PPARγ2. Overexpression of PPARγ significantly prevented the ATF3-mediated inhibition of 3T3-L1 differentiation. Transfection studies with 5' deleted-reporters showed that ATF3 repressed the activity of -2037bp promoter, whereas it did not affect the activity of -1458bp promoter, suggesting that ATF3 responsive element is located between the -2037 and -1458. An electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that ATF3 binds to ATF/CRE site (5'-TGACGTTT-3') between -1537 and -1530. Mutation of the ATF/CRE site abrogated ATF3-mediated transrepression of the PPARγ2 promoter. Treatment with thapsigargin, endoplasmic reticulum (ER) stress inducer, increased ATF3 expression, whereas it decreased PPARγ expression. ATF3 knockdown significantly blocked the thapsigargin-mediated downregulation of PPARγ expression. Furthermore, overexpression of PPARγ prevented inhibition of 3T3-L1 differentiation by thapsigargin. Collectively, these results suggest that ATF3-mediated inhibition of PPARγ expression may contribute to inhibition of adipocyte differentiation during cellular stress including ER stress.
Asunto(s)
Factor de Transcripción Activador 3/metabolismo , Adipocitos/citología , Adipocitos/metabolismo , PPAR gamma/genética , PPAR gamma/metabolismo , Células 3T3-L1 , Factor de Transcripción Activador 3/antagonistas & inhibidores , Factor de Transcripción Activador 3/genética , Adipocitos/efectos de los fármacos , Adipogénesis/genética , Adipogénesis/fisiología , Animales , Sitios de Unión/genética , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Regulación hacia Abajo , Estrés del Retículo Endoplásmico , Técnicas de Silenciamiento del Gen , Células Hep G2 , Humanos , Ratones , Estrés Oxidativo , Regiones Promotoras Genéticas , Tapsigargina/farmacologíaRESUMEN
Obesity-associated adipose tissue hypoxia plays a pivotal role in insulin resistance via impaired adipocyte dysfunction including mitochondria dysfunction. In this study, we investigated the involvement of hypoxia-inducible ATF3 in adipocyte hypoxia-mediated mitochondrial dysfunction. While HIF-1α and ATF3 were increased in white adipose tissue of high fat diet (HFD) obese mice compared with control lean mice, mitochondria-related genes were significantly reduced. Treatment with hypoxia mimetics CoCl(2) or incubation with 2% O(2) impaired mitochondria function as demonstrated by decreases in ATP production, NADH dehydrogenase activity, mitochondrial membrane potential, and reduced expression of mitochondria-related genes including NRF-1, PGC-1α, COX1 and SOD in 3T3-L1 adipocyte cells. Furthermore, overexpression of ATF3 in 3T3-L1 cells also decreased mitochondria function as well as expression of mitochondria-related genes. ATF3 knockdown in 3T3-L1 cells partly prevented the hypoxia-mediated decrease in mitochondria function and expression of mitochondria-related genes. The mitochondria-related genes were decreased in white adipose tissue of ATF3-overexpressing mice compared with wild-type mice. These results suggest that ATF3 may play a role in adipocyte hypoxia-mediated mitochondrial dysfunction in obesity.
Asunto(s)
Factor de Transcripción Activador 3/fisiología , Adipocitos/metabolismo , Mitocondrias/metabolismo , Obesidad/metabolismo , Células 3T3-L1 , Factor de Transcripción Activador 3/genética , Animales , Hipoxia de la Célula , Regulación hacia Abajo , Regulación de la Expresión Génica , Genes Mitocondriales , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mitocondrias/genética , Obesidad/genéticaRESUMEN
In this study, we evaluated the antiobesity effects of Vigna nakashimae (VN) extract and elucidated the underlying mechanisms. VN extract suppressed adipocyte differentiation and significantly attenuated the expression of adipogenic genes in 3T3-L1 cells. It decreased the expression of peroxisome proliferator-activated receptor γ (PPARγ) and its target genes in fully differentiated 3T3-L1 cells. Moreover, it enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl CoA carboxylase (ACC), and increased the expression of fatty acid oxidation genes. In high-fat diet (HFD) fed mice, VN extract suppressed HFD-induced increases in body weight, epididymal fat tissue weight, and hepatic lipid levels, and decreased the plasma levels of triacylglycerols, fatty acid, total cholesterol, and inflammatory cytokines. Consistently with in vitro study results, VN extract prevented HFD-induced increases in the expression of PPARγ and its target genes, and restored the decrease in the phosphorylation of AMPK and ACC in epididymal fat and liver tissues. These findings suggest that Vigna nakashimae prevents obesity through suppression of PPARγ expression and activation of AMPK, and that it might be a useful dietary supplement for the prevention of obesity.
Asunto(s)
Tejido Adiposo/efectos de los fármacos , Fármacos Antiobesidad/farmacología , Fabaceae/química , Metabolismo de los Lípidos/efectos de los fármacos , Obesidad/prevención & control , Extractos Vegetales/farmacología , Semillas/química , Células 3T3-L1 , Acetil-CoA Carboxilasa/genética , Acetil-CoA Carboxilasa/metabolismo , Animales , Fármacos Antiobesidad/aislamiento & purificación , Peso Corporal/efectos de los fármacos , Colesterol/sangre , Dieta Alta en Grasa , Ácidos Grasos/sangre , Regulación de la Expresión Génica/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Obesidad/metabolismo , PPAR gamma/genética , PPAR gamma/metabolismo , Fosforilación , Extractos Vegetales/aislamiento & purificación , Triglicéridos/sangreRESUMEN
Fifteen pig farms were affected by African swine fever (ASF) in South Korea during the outbreaks between 2022 and April 2023. The ASF virus (ASFV) genome was directly extracted from the blood and tissue samples of 15 ASFV-positive pig farms to analyze the genetic characteristics. Phylogenetic analysis revealed that the 15 strains belonged to p72 genotype II and CD2v serogroup 8, which were the central variable region (CVR) I variants of the B602L gene. Fourteen strains were intergenic region (IGR) II variants, containing an additional tandem repeat sequence (TRS), between I73L and I329R, with the exception of one strain from an ASFV-infected pig farm reported on 22 January 2023, which was an IGR I variant. In addition, a single-nucleotide polymorphism (SNP) was detected at position 107 from the start of the IGR between A179L and A137R in six isolates. The findings of this study suggest that the sources of the virus at the pig farms from which these variants originated differed from those of other pig farms.
Asunto(s)
Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Granjas , Filogenia , Perfil Genético , Genotipo , Brotes de Enfermedades , República de Corea/epidemiología , ADN Intergénico , Sus scrofa , Análisis de Secuencia de ADNRESUMEN
Since the first African swine fever (ASF) outbreak occurred at a pig farm in South Korea in September 2019, as of 31 January 2023, 31 ASF cases have occurred at pig farms, while 2799 ASF virus (ASFV)-infected wild boars have been identified. The circulation of ASFV in wild boar populations poses a high risk of spillover to pig farms in the country. However, information on the changes in the pathogenicity of Korean ASFV strains from wild boars is not available. Investigating the pathogenicity of ASFV strains from pig farms is the only way to predict their alterations. In a previous study, no changes in the pathogenicity of ASFV strains circulating during 2019-2021 were identified through animal experiments. In this study, we chose two ASFV strains with potentially reduced pathogenicity among ten viruses obtained from pig premises from 2022 to January 2023 and estimated their pathogenicities and pathological characteristics. All the inoculated pigs died 8-10 days post-inoculation after showing pyrexia, depression, anorexia, and recumbency together with the common pathological lesions of enlarged hemorrhagic lymph nodes and splenomegaly with infarction. These results support that the pathogenicity among ASFV isolates in South Korea still remained unchanged during the study period.
RESUMEN
In South Korea, a total of 21 African swine fever (ASF) infected farms were confirmed during 2019-2021. ASF viruses (ASFVs) were isolated from the blood and spleen samples of the 21 affected farms and their genetic characteristics were analyzed. Phylogenetic analysis indicated that the 21 Korean ASFV strains belonged to p72 genotype II and serogroup 8. All isolates were of the intergenic region (IGR) II variant with 10 tandem repeat sequences between I73R and I329L and the central variable region (CVR) 1 variant of the B602L gene. There were no IGR variations between the A179L and A137R and between the MGF 505 9R and10R nor mutations in the O174L, K145R, MGF 505-5R, CP204L, and Bt/Sj regions. The genes of the 21 ASFV strains were identical to those of Georgia 2007/1 and Chinese and Vietnamese strains (Pig/HLJ/2018, China/2018/AnhuiXCGQ, and ASFV_NgheAn_2019); however, X69R of the J268L region of the 18th isolate (Korea/Pig/Goseong/2021) had three nucleotide (CTA) insertions at the 209th position, which led to the addition of one tyrosine (Y) at the C-terminal. This suggests that there are variations among ASFVs circulating in South Korea and the 18th ASFV-infected farm was due to a variant different from those of the other 20 pig farms.
Asunto(s)
Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Fiebre Porcina Africana/epidemiología , Sus scrofa , Granjas , Filogenia , Genotipo , República de Corea/epidemiología , Brotes de Enfermedades/veterinariaRESUMEN
In October 2020, a suspect case of African swine fever (ASF) was detected at an abattoir located in the north-central border region of South Korea. The farm of origin was traced and confirmed positive for ASF. This recurrence was following a period of absence of outbreaks in domestic pigs after the first incursion in 2019, during which a total of 14 domestic pig farms were confirmed between September and October 2019. In 2020, a total of two farms were confirmed, and the molecular characterization of key regions of the genome showed that the two isolates from 2020 were identical with the previous isolates from South Korea in 2019. The continued spread and circulation of ASF in the wild boar population represents an increased risk of spill-over outbreaks in domestic pigs, and, therefore, additional control measures should be implemented for farms in these regions, including a heightened level of surveillance. This was the case for the index farm, which was required to send pigs only to the designated abattoir at which the suspect case was quickly detected. The improvement of biosecurity in pig farms, particularly at the wild boar-domestic pig interface, will be key to the successful control of ASF in the region.
RESUMEN
African swine fever (ASF) was first reported in South Korea in September 2019, and as of 31 December 2021, a total of 21 cases in domestic pig farms and 1875 ASFV-infected wild boars have been confirmed in the country. With the continued circulation of ASF in wild boars, and subsequent outbreaks in domestic pigs, concerns were raised about the possible changes in virulence occurring among African swine fever viruses (ASFV) circulating in South Korea. In this study, four Korean ASFV strains isolated from domestic pig farms at different time points between 2019 and 2021 were chosen, and used to experimentally infect domestic pigs by intramuscular inoculation to compare their virulence. All challenged pigs died at 4-9 days post-inoculation, with many showing clinical symptoms of fever, depression, loss of appetite, and recumbency. Gross lesions observed at necropsy included enlargement and hemorrhage of the lymph nodes and hydropericardium. The study showed that all four Korean ASFV isolates caused acute forms of illness, which supports the view that virulence among the circulating ASFV isolates in South Korea remained unchanged and highly virulent during this period.
Asunto(s)
Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Humanos , Fiebre Porcina Africana/epidemiología , Granjas , Virulencia , Sus scrofa , República de Corea/epidemiologíaRESUMEN
Random mutagenesis was performed on beta-agarase, AgaB, from Zobellia galactanivorans to improve its catalytic activity and thermostability. The activities of three mutants E99K, T307I and E99K-T307I were approx. 140, 190 and 200%, respectively, of wild type beta-agarase (661 U/mg) at 40 degrees C. All three mutant enzymes were stable up to 50 degrees C and E99K-T307I had the highest thermostability. The melting temperature (Tm) of E99K-T307I, determined by CD spectra, was increased by 5.2 degrees C over that of the wild-type enzyme (54.6 degrees C). Activities of both the wild-type and E99K-T307I enzymes, as well as their overall thermostabilities, increased in 1 mM CaCl2. The E99K-T307I enzyme was stable at 55 degrees C with 1 mM CaCl2, reaching 260% of the activity the wild-type enzyme held at 40 degrees C without CaCl2.
Asunto(s)
Proteínas Bacterianas/química , Flavobacteriaceae/enzimología , Glicósido Hidrolasas/química , Calor , Mutagénesis , Sustitución de Aminoácidos/genética , Proteínas Bacterianas/genética , Cloruro de Calcio/metabolismo , Dicroismo Circular , Análisis Mutacional de ADN , Estabilidad de Enzimas , Flavobacteriaceae/genética , Glicósido Hidrolasas/genética , Proteínas Mutantes/química , Proteínas Mutantes/genética , Mutación Missense , Estabilidad Proteica , Temperatura de TransiciónRESUMEN
On 17 September 2019, the first outbreak of African swine fever in a pig farm was confirmed in South Korea. By 9 October, 14 outbreaks of ASF in domestic pigs had been diagnosed in 4 cities/counties. We isolated viruses from all infected farms and performed genetic characterization. The phylogenetic analysis showed that all of fourteen ASFV isolates in South Korea belong to genotype II and serogroup 8. Additionally, all isolates had an intergenic region (IGR) II variant with additional tandem repeat sequences (TRSs) between the I73R and I329L genes and showed characteristics of central variable region (CVR) 1 of the B602L gene and IGR 1 of MGF 505 9R/10R genes. These are identical to the genetic characteristics of some European isolates and Chinese isolates.
Asunto(s)
Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/aislamiento & purificación , Fiebre Porcina Africana/virología , Brotes de Enfermedades , Filogenia , Fiebre Porcina Africana/epidemiología , Virus de la Fiebre Porcina Africana/clasificación , Animales , Células Cultivadas , ADN Intergénico , ADN Viral/genética , Granjas , Genotipo , Macrófagos Alveolares/virología , República de Corea/epidemiología , Análisis de Secuencia de ADN , Serogrupo , Sus scrofa/virología , PorcinosRESUMEN
The murine dopamine receptor regulating factor (DRRF) gene is transcribed from a TATA-less promoter that has several putative Sp1 binding sites. The present investigation identifies functional transcription factors that modulate the expression of this gene. In the D2-dopamine receptor expressing NB41A3 cells, Sp1 potently activates transcription from the DRRF promoter in pCAT-DRRF-1153/+17, while DRRF itself effectively inhibits it. Sp1 also activates this promoter in pCAT-DRRF-310/+17. In competitive co-transfection experiments, DRRF represses the transcriptional activation induced by Sp1, while Sp1 de-represses the inhibitory effect of DRRF. Deletion of the 31 bp fragment between -1153 and -1122 decreased basal transcription down to about 60%. This fragment contains a functional AP1 binding site. In addition, deletion of the 129 bp region between -901 and -772 further decreased transcription. The latter region has a functional AP2 binding site. The present observations suggest that DRRF auto-regulates its own promoter by competing with Sp1 and that both AP1 and AP2 modulate expression of this gene.
Asunto(s)
Factores de Transcripción de Tipo Kruppel/genética , Transcripción Genética , Animales , Línea Celular Tumoral , Ratones , Regiones Promotoras Genéticas , Eliminación de Secuencia , Factor de Transcripción Sp1/genética , Factor de Transcripción AP-1/genética , Factor de Transcripción AP-2/genética , Sitio de Iniciación de la Transcripción , Activación TranscripcionalRESUMEN
Previous studies have shown that tri- or di-methylation of histone H3 at lysine 9 (H3K9me3/me2) on the promoter of the peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα) contribute to the repression of PPARγ and C/EBPα and inhibition of adipogenesis in 3T3-L1 preadipocytes. The balance of histone methylation is regulated by histone methyltransferases and demethylases. However, it is poorly understood which demethylases are responsible for removing H3K9me3/me2 on the promoter of PPARγ and C/EBPα. JMJD2B is a H3K9me3/me2 demethylase that was previously shown to activate adipogenesis by promoting mitotic clonal expansion. Nevertheless, it remains unclear whether JMJD2B plays a role in the regulation of adipogenesis by removing H3K9me3/me2 on the promoter of PPARγ and C/EBPα and subsequently activating PPARγ and C/EBPα expression. Here, we showed that JMJD2B decreased H3K9me3/me2 on the promoter of PPARγ and C/EBPα, which in turn stimulated the expression of PPARγ and C/EBPα. JMJD2B knockdown using siRNA in 3T3-L1 preadipocytes repressed the expression of PPARγ and C/EBPα, resulting in inhibition of adipogenesis. This was accompanied by increased enrichment of H3K9me3/me2 on the promoter of PPARγ and C/EBPα. In contrast, overexpression of JMJD2B increased the expression of PPARγ and C/EBPα, which was accompanied by decreased enrichment of H3K9me3/me2 on the promoter and activated adipogenesis. Together, these results indicate that JMJD2B regulates PPARγ and C/EBPα during adipogenesis.
Asunto(s)
Proteínas Potenciadoras de Unión a CCAAT/genética , Regulación de la Expresión Génica , Histonas/metabolismo , Histona Demetilasas con Dominio de Jumonji/metabolismo , PPAR gamma/genética , Células 3T3-L1 , Adipocitos/citología , Adipocitos/metabolismo , Adipogénesis/genética , Animales , Histona Demetilasas con Dominio de Jumonji/genética , Metilación , Ratones , Regiones Promotoras GenéticasRESUMEN
Gomisin N (GN) is a physiological lignan derived from Schisandra chinensis. In the present study, we investigated the inhibitory effects of GN on differentiation of 3T3-L1 preadipocytes and the anti-obesity effects of GN in high-fat diet (HFD)-induced obese mice. Incubation with GN significantly inhibited the differentiation of 3T3-L1 preadipocytes in a dose-dependent manner. This inhibitory effect primarily occurred at an early adipogenic stage through impairment of mitotic clonal expansion (MCE) caused by cell cycle arrest at the G1/S phase transition. GN inhibited the extracellular signal-regulated kinase and phosphoinositide 3-kinase/protein kinase B signaling in the MCE process and activated AMP-activated protein kinase. Furthermore, GN downregulated CCAT/enhancer-binding protein ß (C/EBPß) and histone H3K9 demethylase JMJD2B during early stages of adipogenesis, and therefore repressed the expression of C/EBPß-targeted cell cycle genes. In addition, GN also repressed the expression of histone H3K4 methyltransferase MLL4 and reduced PPARγ expression. Moreover, GN effectively lowered the final body weight, adipose tissue mass, and reduced the serum levels of glucose, total triglyceride, and cholesterol in the HFD-induced obese mice. GN also markedly reduced hepatic triglyceride level induced by HFD. Collectively, these findings suggest that GN has potential as a novel agent for the prevention and treatment of obesity.
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Adipogénesis/efectos de los fármacos , Lignanos/farmacología , Lignanos/uso terapéutico , Obesidad/tratamiento farmacológico , Obesidad/prevención & control , Compuestos Policíclicos/farmacología , Compuestos Policíclicos/uso terapéutico , Células 3T3-L1 , Adipocitos/citología , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Animales , Proteína beta Potenciadora de Unión a CCAAT/metabolismo , Células Clonales , Quinasa 2 Dependiente de la Ciclina/metabolismo , Quinasa 6 Dependiente de la Ciclina/metabolismo , Ciclinas/metabolismo , Ciclooctanos/farmacología , Ciclooctanos/uso terapéutico , Dieta Alta en Grasa , Regulación hacia Abajo/efectos de los fármacos , Hígado Graso/complicaciones , Hígado Graso/tratamiento farmacológico , Hígado Graso/patología , N-Metiltransferasa de Histona-Lisina , Masculino , Ratones , Ratones Endogámicos C57BL , Mitosis/efectos de los fármacos , Obesidad/sangre , Obesidad/complicaciones , PPAR gamma/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
In this study, we performed high throughput RNA sequencing at the preadipocyte (D0) and differentiated adipocyte (D7) stages of primary brown preadipocyte differentiation in order to characterize the transcriptional events regulating differentiation and function. Compared to the preadipocyte stage (D0), 6,668 genes were identified as differentially expressed genes (DEGs) with a fold change of ≥ 2.0 at the differentiated adipocyte stage (D7). Several adipogenic genes including peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein-α (C/EBPα), and Krüppel-like factor (KLF) family genes were differentially expressed at D0 and D7. Since KLF16 gene expression was downregulated at day 7 and its adipogenic function has not been characterized, we investigated its role in adipogenesis. Knockdown of KLF16 stimulated the differentiation of both brown and 3T3-L1 preadipocytes, and led to increased PPARγ expression. However, overexpression of KLF16 had opposite effects. Furthermore, KLF16 downregulated PPARγ expression in brown adipocytes and inhibited its promoter activity. These results indicate that KLF16 inhibits adipogenesis through downregulation of PPARγ expression.
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Adipogénesis/fisiología , Factores de Transcripción de Tipo Kruppel/fisiología , Adipogénesis/genética , Tejido Adiposo Pardo/citología , Animales , Femenino , Regulación de la Expresión Génica , Factores de Transcripción de Tipo Kruppel/genética , Masculino , Ratones , Ratones Endogámicos C57BL , PPAR gamma/genética , PPAR gamma/metabolismo , Análisis de Secuencia de ARN , TranscriptomaRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Schisandra chinensis (Turcz.) Baill. (SC) is a traditional Chinese herbal medicine with diverse pharmacological activities for treatment of various human diseases. Endoplasmic reticulum (ER) stress is associated with the pathogenesis of nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the protective effects of methanol extract of Schisandra chinensis (SC extract) against ER stress-induced NAFLD in vitro and in vivo. MATERIAL AND METHODS: The protective effects of SC extract were examined in tunicamycin- or palmitate-treated HepG2 cells in vitro, and in tunicamycin-injected mice or high fed diet (HFD) obese mice in vivo. Expression of ER stress markers including glucose regulated protein 78 (GRP78), C/EBP homolog protein (CHOP), and X-box-binding protein-1 (XBP-1), and triglyceride accumulation were measured in HepG2 cells and in the liver of mice. RESULTS: SC extract significantly inhibited expression of tunicamycin-induced ER stress markers in tunicamycin-treated HepG2 cells and in the liver of tunicamycin-injected mice, and it also inhibited tunicamycin-induced triglyceride accumulation. Similar observations were made under physiological ER stress conditions such as in palmitate-treated HepG2 cells and in the liver of HFD obese mice. In addition, SC extract repressed the expression of inflammatory genes and lipogenic genes in palmitate-treated HepG2 cells. Schisandrin, an abundant bioactive lignan in SC extract, inhibited the expression of ER stress markers in tunicamycin-or palmitate-treated HepG2 cells, whereas Gomisin J did not affect ER stress markers. CONCLUSIONS: SC attenuates ER stress and prevents development of NAFLD. SC may be useful as a pharmacological agent for protection against ER stress-induced human diseases.