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Sample records for factor sterol regulatory

  1. Activation of Sterol Regulatory Element Binding Factors by Fenofibrate and Gemfibrozil Stimulate Myelination in Zebrafish

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    Yuhei Nishimura

    2016-07-01

    Full Text Available Oligodendrocytes are major myelin-producing cells and play essential roles in the function of a healthy nervous system. However, they are also one of the most vulnerable neural cell types in the central nervous system (CNS, and myelin abnormalities in the CNS are found in a wide variety of neurological disorders, including multiple sclerosis, adrenoleukodystrophy, and schizophrenia. There is an urgent need to identify small molecular weight compounds that can stimulate myelination. In this study, we performed comparative transcriptome analysis to identify pharmacodynamic effects common to miconazole and clobetasol, which have been shown to stimulate myelination by mouse oligodendrocyte progenitor cells (OPCs. Of the genes differentially expressed in both miconazole- and clobetasol-treated mouse OPCs compared with untreated cells, we identified differentially expressed genes (DEGs common to both drug treatments. Gene ontology analysis revealed that these DEGs are significantly associated with the sterol biosynthetic pathway, and further bioinformatics analysis suggested that sterol regulatory element binding factors (SREBFs might be key upstream regulators of the DEGs. In silico screening of a public database for chemicals associated with SREBF activation identified fenofibrate, a peroxisome proliferator-activated receptor α (PPARα agonist, as a drug that increases the expression of known SREBF targets, raising the possibility that fenofibrate may also stimulate myelination. To test this, we performed in vivo imaging of zebrafish expressing a fluorescent reporter protein under the control of the myelin basic protein (mbp promoter. Treatment of zebrafish with fenofibrate significantly increased expression of the fluorescent reporter compared with untreated zebrafish. This increase was attenuated by co-treatment with fatostatin, a specific inhibitor of SREBFs, confirming that the fenofibrate effect was mediated via SREBFs. Furthermore, incubation

  2. Sterol regulatory element binding transcription factor 1 (SREBF1) polymorphism and milk fatty acid composition.

    Science.gov (United States)

    Nafikov, R A; Schoonmaker, J P; Korn, K T; Noack, K; Garrick, D J; Koehler, K J; Minick-Bormann, J; Reecy, J M; Spurlock, D E; Beitz, D C

    2013-04-01

    Milk is known to contain high concentrations of saturated fatty acids-such as palmitic (16:0), myristic (14:0), and lauric (12:0) acids-that can raise plasma cholesterol in humans, making their presence in milk undesirable. The main objective of our candidate gene study was to develop genetic markers that can be used to improve the healthfulness of bovine milk. The sterol regulatory element binding transcription factor 1 (SREBF1) known to regulate the transcription of lipogenic genes together with SREBF chaperone and insulin induced gene 1 were the candidate genes. The results showed significant association of the overall SREBF1 haplotypes with milk production and variations in lauric (12:0) and myristic (14:0) acid concentrations in milk. Haplotype H1 of SREBF1 was the most desirable to improve milk healthfulness because it was significantly associated with lower lauric (12:0) and myristic (14:0) acid concentrations compared with haplotype H3 of SREBF1, and lower lauric acid (12:0) concentration compared with haplotype H2 of SREBF1. Haplotype H1 of SREBF1, however, was significantly associated with lower milk production compared with haplotype H3 of SREBF1. We did not detect any significant associations between genetic polymorphisms in insulin induced gene 1 (INSIG1) and SREBF chaperone and milk fatty acid composition. In conclusion, genetic polymorphisms in SREBF1 can be used to develop genetic tools for the selection of animals producing milk with healthier fatty acid composition.

  3. Maintaining cholesterol homeostasis:Sterol regulatory element-binding proteins

    Institute of Scientific and Technical Information of China (English)

    Lutz W. Weber; Meinrad Boll; Andreas Stampfl

    2004-01-01

    The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins are members of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP).The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones,cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.

  4. FoxO4 interacts with the sterol regulatory factor SREBP2 and the hypoxia inducible factor HIF2α at the CYP51 promoter.

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    Zhu, Jun; Jiang, Xiangning; Chehab, Farid F

    2014-03-01

    The late steps of cholesterol biosynthesis are oxygen demanding, requiring eleven oxygen molecules per synthesized cholesterol molecule. A key enzymatic reaction, which occurs at the top of the Bloch and Kandutsch-Russell pathways, is the demethylation of lanosterol and dihydrolanosterol (DHL). This reaction is catalyzed by lanosterol 14α demethylase (CYP51) and requires three oxygen molecules. Thus, it is the first step in the distal pathway to be susceptible to oxygen deprivation. Having previously identified that the forkhead transcription factor 4 (FoxO4) represses CYP51 expression, we aimed to characterize its role at the CYP51 promoter. Hypoxia-treated 3T3L1 cells showed decreased cholesterol biosynthesis, accumulation of lanosterol/DHL, and stimulation of FoxO4 expression and its cytoplasmic translocation to the nucleus. Transfection assays with a CYP51 promoter reporter gene revealed that FoxO4 and sterol regulatory element binding protein (SREBP)2 exert a stimulatory effect, whereas FoxO4 and the hypoxia inducible factor (HIF)2α repress CYP51 promoter activity. Electromobility shift, chromatin immunoprecipitation, pull-down, and coimmunoprecipitation assays show that FoxO4 interacts with SREBP2 and HIF2α to modulate CYP51 promoter activity. We also show an inverse correlation between FoxO4 and CYP51 in adipose tissue of ob/ob mice and mouse fetal cortical neurons exposed to hypoxia. Overall, these studies demonstrate a role for FoxO4 in the regulation of CYP51 expression.

  5. Sterol regulatory element binding transcription factor 1 expression and genetic polymorphism significantly affect intramuscular fat deposition in the longissimus muscle of Erhualian and Sutai pigs.

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    Chen, J; Yang, X J; Xia, D; Chen, J; Wegner, J; Jiang, Z; Zhao, R Q

    2008-01-01

    Two experiments were performed to elucidate the role of sterol regulatory element binding transcription factor 1 (SREBF1) in i.m. fat (IMF) deposition in pigs. In Exp. 1, LM samples were removed from 4 male and 4 female Erhualian piglets at 3, 20, and 45 d of age, and SREBF1 mRNA expression level and IMF content were measured. Intramuscular fat content and expression of SREBF1 mRNA was greater (P Single-strand conformation polymorphism (SSCP) analysis of the reverse transcription PCR products of the SREBF1 gene revealed 3 genotypes in Sutai pigs with frequencies of 50% for AA, 36% for AB, and 14% for BB, respectively. Both SREBF1 mRNA level and IMF content in muscle were greater (P < 0.05) in AB and BB animals than in AA animals, whereas no difference in backfat thickness was observed among the 3 genotypes. Sequencing analysis identified 2 SNP at T1006C and C1033T within the open reading frame of the SREBF1 gene (NM_214157). Although both are silent mutations, they affected the secondary structure of SREBF1 mRNA. These results suggest that SREBF1 might play an important role in regulation of muscle fat deposition during postnatal growth of pigs. The SNP identified in the SREBF1 gene suggest that it could be used as a genetic marker to improve IMF content in pigs.

  6. Hepatitis C virus nonstructural protein-5A activates sterol regulatory element-binding protein-1c through transcription factor Sp1

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Zhonghua; Qiao, Ling; Zhou, Yan [Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3 (Canada); Babiuk, Lorne A. [University of Alberta, Edmonton, Alberta (Canada); Liu, Qiang, E-mail: qiang.liu@usask.ca [Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3 (Canada)

    2010-11-19

    Research highlights: {yields} A chimeric subgenomic HCV replicon expresses HCV-3a NS5A in an HCV-1b backbone. {yields} HCV-3a NS5A increases mature SREBP-1c protein level. {yields} HCV-3a NS5A activates SREBP-1c transcription. {yields} Domain II of HCV-3a NS5A is more effective in SREBP-1c promoter activation. {yields} Transcription factor Sp1 is required for SREBP-1c activation by HCV-3a NS5A. -- Abstract: Steatosis is an important clinical manifestation of hepatitis C virus (HCV) infection. The molecular mechanisms of HCV-associated steatosis are not well understood. Sterol regulatory element-binding protein-1c (SREBP-1c) is a key transcription factor which activates the transcription of lipogenic genes. Here we showed that the nuclear, mature SREBP-1c level increases in the nucleus of replicon cells expressing HCV-3a nonstructural protein-5A (NS5A). We further showed that HCV-3a NS5A up-regulates SREBP-1c transcription. Additional analysis showed that transcriptional factor Sp1 is involved in SREBP-1c activation by HCV-3a NS5A because inhibition of Sp1 activity by mithramycin A or a dominant-negative Sp1 construct abrogated SREBP-1c promoter activation by HCV-3a NS5A. In addition, chromatin immunoprecipitation (ChIP) assay demonstrated enhanced binding of Sp1 on the SREBP-1c promoter in HCV-3a NS5A replicon cells. These results showed that HCV-3a NS5A activates SREBP-1c transcription through Sp1. Taken together, our results suggest that HCV-3a NS5A is a contributing factor for steatosis caused by HCV-3a infection.

  7. A novel processing system of sterol regulatory element-binding protein-1c regulated by polyunsaturated fatty acid.

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    Nakakuki, Masanori; Kawano, Hiroyuki; Notsu, Tatsuto; Imada, Kazunori; Mizuguchi, Kiyoshi; Shimano, Hitoshi

    2014-05-01

    The proteolytic cascade is the key step in transactivation of sterol regulatory element-binding proteins (SREBPs), a transcriptional factor of lipid synthesis. Proteolysis of SREBP-2 is strictly regulated by sterols, but that of SREBP-1c was not strongly sterol-regulated, but inhibited by polyunsaturated fatty acids (PUFAs). In this study, the proteolytic processing of SREBP-1 and -2 was examined by transfection studies of cDNA-encoding mutants in which all the known cleavage sites were disrupted. In cultured cells, sterol-regulated SREBP-2 processing was completely eliminated by mutation of cleavage sites. In contrast, the corresponding SREBP-1c mutants as well as wild type exhibited large amounts of cleaved products in the nuclear extracts from culture cells and murine liver in vivo. The nuclear form of the mutant SREBP-1c was induced by delipidated condition and suppressed by eicosapentaenoic acid, an n-3 PUFA, but not by sterols. This novel processing mechanism was affected by neither SREBP cleavage-activating protein (SCAP) nor insulin-induced gene (Insig)-1, unlike SREBP-2, but abolished by a serine protease inhibitor. Through analysis of deletion mutant, a site-2 protease recognition sequence (DRSR) was identified to be involved in this novel processing. These findings suggest that SREBP-1c cleavage could be subjected to a novel PUFA-regulated cleavage system in addition to the sterol-regulatory SCAP/Insig system.

  8. Zinc finger transcription factors displaced SREBP proteins as the major Sterol regulators during Saccharomycotina evolution.

    Directory of Open Access Journals (Sweden)

    Sarah L Maguire

    2014-01-01

    Full Text Available In most eukaryotes, including the majority of fungi, expression of sterol biosynthesis genes is regulated by Sterol-Regulatory Element Binding Proteins (SREBPs, which are basic helix-loop-helix transcription activators. However, in yeasts such as Saccharomyces cerevisiae and Candida albicans sterol synthesis is instead regulated by Upc2, an unrelated transcription factor with a Gal4-type zinc finger. The SREBPs in S. cerevisiae (Hms1 and C. albicans (Cph2 have lost a domain, are not major regulators of sterol synthesis, and instead regulate filamentous growth. We report here that rewiring of the sterol regulon, with Upc2 taking over from SREBP, likely occurred in the common ancestor of all Saccharomycotina. Yarrowia lipolytica, a deep-branching species, is the only genome known to contain intact and full-length orthologs of both SREBP (Sre1 and Upc2. Deleting YlUPC2, but not YlSRE1, confers susceptibility to azole drugs. Sterol levels are significantly reduced in the YlUPC2 deletion. RNA-seq analysis shows that hypoxic regulation of sterol synthesis genes in Y. lipolytica is predominantly mediated by Upc2. However, YlSre1 still retains a role in hypoxic regulation; growth of Y. lipolytica in hypoxic conditions is reduced in a Ylupc2 deletion and is abolished in a Ylsre1/Ylupc2 double deletion, and YlSre1 regulates sterol gene expression during hypoxia adaptation. We show that YlSRE1, and to a lesser extent YlUPC2, are required for switching from yeast to filamentous growth in hypoxia. Sre1 appears to have an ancestral role in the regulation of filamentation, which became decoupled from its role in sterol gene regulation by the arrival of Upc2 in the Saccharomycotina.

  9. Association of variants in the sterol regulatory element-binding factor 1 gene (SREBF1) with type 2 diabetes, glycemia, and insulin resistance - A study of 15,734 Danish subjects

    DEFF Research Database (Denmark)

    Grarup, Niels; Stender-Petersen, Kirstine L; Andersson, Ehm A

    2008-01-01

    Objective: We evaluated association of variants in the sterol regulatory element-binding factor 1 gene (SREBF1) with type 2 diabetes. Due to the previous inconclusive quantitative trait associations, we also did studies of intermediate quantitative phenotypes. Research design and methods: We...... genotyped four variants in SREBF1 in the population-based Inter99 cohort (n=6,070), the Danish ADDITION study (n=8,662) and in additional type 2 diabetic patients (n=1,002). The case-control studies involved 2,980 type 2 diabetic patients and 4,522 glucose-tolerant subjects. Results: The minor alleles...... of the rs2297508, rs11868035 and rs1889018 (linkage disequilibrium R(2)=0.6-0.8) associated with a modestly increased risk of type 2 diabetes (rs2297508: OR 1.17 [95% CI 1.05-1.30], P=0.003) which was confirmed in meta-analyses of all published studies (rs2297508 G-allele: OR 1.08 [1.03-1.14] per allele, P...

  10. Caloric restriction-associated remodeling of rat white adipose tissue: effects on the growth hormone/insulin-like growth factor-1 axis, sterol regulatory element binding protein-1, and macrophage infiltration.

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    Chujo, Yoshikazu; Fujii, Namiki; Okita, Naoyuki; Konishi, Tomokazu; Narita, Takumi; Yamada, Atsushi; Haruyama, Yushi; Tashiro, Kosuke; Chiba, Takuya; Shimokawa, Isao; Higami, Yoshikazu

    2013-08-01

    The role of the growth hormone (GH)-insulin-like growth factor (IGF)-1 axis in the lifelong caloric restriction (CR)-associated remodeling of white adipose tissue (WAT), adipocyte size, and gene expression profiles was explored in this study. We analyzed the WAT morphology of 6-7-month-old wild-type Wistar rats fed ad libitum (WdAL) or subjected to CR (WdCR), and of heterozygous transgenic dwarf rats bearing an anti-sense GH transgene fed ad libitum (TgAL) or subjected to CR (TgCR). Although less effective in TgAL, the adipocyte size was significantly reduced in WdCR compared with WdAL. This CR effect was blunted in Tg rats. We also used high-density oligonucleotide microarrays to examine the gene expression profile of WAT of WdAL, WdCR, and TgAL rats. The gene expression profile of WdCR, but not TgAL, differed greatly from that of WdAL. The gene clusters with the largest changes induced by CR but not by Tg were genes involved in lipid biosynthesis and inflammation, particularly sterol regulatory element binding proteins (SREBPs)-regulated and macrophage-related genes, respectively. Real-time reverse-transcription polymerase chain reaction analysis confirmed that the expression of SREBP-1 and its downstream targets was upregulated, whereas the macrophage-related genes were downregulated in WdCR, but not in TgAL. In addition, CR affected the gene expression profile of Tg rats similarly to wild-type rats. Our findings suggest that CR-associated remodeling of WAT, which involves SREBP-1-mediated transcriptional activation and suppression of macrophage infiltration, is regulated in a GH-IGF-1-independent manner.

  11. Functional interaction of hepatic nuclear factor-4 and peroxisome proliferator-activated receptor-gamma coactivator 1alpha in CYP7A1 regulation is inhibited by a key lipogenic activator, sterol regulatory element-binding protein-1c.

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    Ponugoti, Bhaskar; Fang, Sungsoon; Kemper, Jongsook Kim

    2007-11-01

    Insulin inhibits transcription of cholesterol 7alpha-hydroxylase (Cyp7a1), a key gene in bile acid synthesis, and the hepatic nuclear factor-4 (HNF-4) site in the promoter was identified as a negative insulin response sequence. Using a fasting/feeding protocol in mice and insulin treatment in HepG2 cells, we explored the inhibition mechanisms. Expression of sterol regulatory element-binding protein-1c (SREBP-1c), an insulin-induced lipogenic factor, inversely correlated with Cyp7a1 expression in mouse liver. Interaction of HNF-4 with its coactivator, peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha), was observed in livers of fasted mice and was reduced after feeding. Conversely, HNF-4 interaction with SREBP-1c was increased after feeding. In vitro studies suggested that SREBP-1c competed with PGC-1alpha for direct interaction with the AF2 domain of HNF-4. Reporter assays showed that SREBP-1c, but not of a SREBP-1c mutant lacking the HNF-4 interacting domain, inhibited HNF-4/PGC-1alpha transactivation of Cyp7a1. SREBP-1c also inhibited PGC-1alpha-coactivation of estrogen receptor, constitutive androstane receptor, pregnane X receptor, and farnesoid X receptor, implying inhibition of HNF-4 by SREBP-1c could extend to other nuclear receptors. In chromatin immunoprecipitation studies, HNF-4 binding to the promoter was not altered, but PGC-1alpha was dissociated, SREBP-1c and histone deacetylase-2 (HDAC2) were recruited, and acetylation of histone H3 was decreased upon feeding. Adenovirus-mediated expression of a SREBP-1c dominant-negative mutant, which blocks the interaction of SREBP-1c and HNF-4, partially but significantly reversed the inhibition of Cyp7a1 after feeding. Our data show that SREBP-1c functions as a non-DNA-binding inhibitor and mediates, in part, suppression of Cyp7a1 by blocking functional interaction of HNF-4 and PGC-1alpha. This mechanism may be relevant to known repression of many other HNF-4 target genes upon

  12. Expression of sterol regulatory element-binding transcription factor (SREBF 2 and SREBF cleavage-activating protein (SCAP in human atheroma and the association of their allelic variants with sudden cardiac death

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    Kytömäki Leena

    2008-12-01

    Full Text Available Abstract Background Disturbed cellular cholesterol homeostasis may lead to accumulation of cholesterol in human atheroma plaques. Cellular cholesterol homeostasis is controlled by the sterol regulatory element-binding transcription factor 2 (SREBF-2 and the SREBF cleavage-activating protein (SCAP. We investigated whole genome expression in a series of human atherosclerotic samples from different vascular territories and studied whether the non-synonymous coding variants in the interacting domains of two genes, SREBF-2 1784G>C (rs2228314 and SCAP 2386A>G, are related to the progression of coronary atherosclerosis and the risk of pre-hospital sudden cardiac death (SCD. Methods Whole genome expression profiling was completed in twenty vascular samples from carotid, aortic and femoral atherosclerotic plaques and six control samples from internal mammary arteries. Three hundred sudden pre-hospital deaths of middle-aged (33–69 years Caucasian Finnish men were subjected to detailed autopsy in the Helsinki Sudden Death Study. Coronary narrowing and areas of coronary wall covered with fatty streaks or fibrotic, calcified or complicated lesions were measured and related to the SREBF-2 and SCAP genotypes. Results Whole genome expression profiling showed a significant (p = 0.02 down-regulation of SREBF-2 in atherosclerotic carotid plaques (types IV-V, but not in the aorta or femoral arteries (p = NS for both, as compared with the histologically confirmed non-atherosclerotic tissues. In logistic regression analysis, a significant interaction between the SREBF-2 1784G>C and the SCAP 2386A>G genotype was observed on the risk of SCD (p = 0.046. Men with the SREBF-2 C allele and the SCAP G allele had a significantly increased risk of SCD (OR 2.68, 95% CI 1.07–6.71, compared to SCAP AA homologous subjects carrying the SREBF-2 C allele. Furthermore, similar trends for having complicated lesions and for the occurrence of thrombosis were found, although the

  13. Association of sterol regulatory element binding protein 2 and insulin-like growth factor binding protein 3 genetic polymorphisms with avascular necrosis of the femoral head in the Chinese population

    Institute of Scientific and Technical Information of China (English)

    SONG Yang; DU Zhen-wu; LI Qiu-ju; ZHANG Gui-zhen; WANG Ling-ling; WU Ning; WANG Jin-cheng; GAO Zhong-li

    2012-01-01

    Background Sterol regulatory element binding protein(SREBP)-2 plays a key role in lipid homeostasis by stimulating gene expression of cholesterol biosynthetic pathways.The insulin-like growth factor binding protein(IGFBP)family regulates growth and metabolism,especially bone cell metabolism,and correlates with osteonecrosis.However,association of their gene polymorphisms with risk of avascular necrosis of the femoral head(ANFH)has rarely been reported.We determined whether SREBP-2 and IGFBP-3 gene polymorphisms were associated with increased ANFH risk in the Chinese population.Methods Two single nucleotide polymorphisms of SREBP2 gene,rs2267439 and rs2267443,and one of IGFBP-3 gene,rs2453839,were selected and genotyped in 49 ANFH patients and 42 control individuals by direct sequencing assay.Results The frequencies of rs2267439 TT and rs2267443 GA of SREBP2 and rs2453839 TT and CT of IGFBP-3 in the ANFH group showed increased and decreased tendencies(against normal control group),respectively.Interaction analysis of genes revealed that the frequency of carrying rs2267439 TT and rs2267443 GA genctypes of SREBF-2 in ANFH patients was significantly higher than in the control group(P<0.05).Association analysis between polymorphisms and clinical phenotype demonstrated that the disease course in ANFH patients with the rs2453839 TT genotype of IGFBP-3 was significantly shorter than that of CT+CC carriers(P<0.01).CT+CC genotype frequency in patients with stage Ⅲ/Ⅳ?bilateral hip lesions was significantly higher than in those with stage Ⅲ/Ⅳ?unilateral lesions and stage Ⅱ/Ⅲ?bilateral lesions(P<0.05-0.02).Conclusions Our results suggested that interaction of SREBP-2 gene polymorphisms and the relationship between the polymorphisms and clinical phenotype of IGFBP-3 were closely related to increased ANFH risk in the Chinese population.The most significant finding was that the CT+CC genotype carriers of IGFBP-3 rs2453839 were highly associated with the

  14. Lanosterol metabolism and sterol regulatory element binding protein (SREBP) expression in male germ cell maturation.

    Science.gov (United States)

    Fon Tacer, Klementina; Kalanj-Bognar, Svjetlana; Waterman, Michael R; Rozman, Damjana

    2003-06-01

    Expression of genes involved in cholesterol biosynthesis in male germ cells is insensitive to the negative cholesterol feedback regulation, in contrast to cholesterol level-sensitive/sterol regulatory element binding protein (SREBP)-dependent gene regulation in somatic cells. The role of sterol regulatory element binding proteins in spermatogenic cells was an enigma until recently, when a soluble, 55kDa cholesterol-insensitive form of SREBP2 (SREBP2gc) was discovered [Mol. Cell. Endocrinol. 22 (2002) 8478], being translated from a germ cell-specific SREBP2 mRNA. Our RT-PCR results also show that SREBP2 as well as SREBP1c mRNAs are detectable in prepubertal and postpubertal male germ cells while SREBP1a is not detected. Surprisingly, three SREBP2 immunoreactive proteins (72, 63 and 55kDa), that are not present in mouse liver nuclei, reside in testis nuclei of prepubertal and adult mice. The 55kDa protein is likely SREBP2gc, the other two isoforms are novel. HPLC measurements in liver and testes of fasted prepubertal and postpubertal mice showed no significant difference in cholesterol level. However, FF-MAS and lanosterol/testis-meiosis activating sterol (T-MAS) intermediates that are detectable mainly in testes, increase in fasted postpubertal mice which coincides well with the elevated level of 68kDa SREBP2. Similar to SREBP2gc, the two novel SREBP2 immunoreactive proteins seem to be insensitive to the level of cholesterol.

  15. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    OpenAIRE

    Andreas Bitter; Nüssler, Andreas K.; Thasler, Wolfgang E.; Kathrin Klein; Zanger, Ulrich M.; Matthias Schwab; Oliver Burk

    2015-01-01

    Background/Aims: Sterol regulatory element-binding protein (SREBP) 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human li...

  16. Xanthohumol Improves Diet-induced Obesity and Fatty Liver by Suppressing Sterol Regulatory Element-binding Protein (SREBP) Activation.

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    Miyata, Shingo; Inoue, Jun; Shimizu, Makoto; Sato, Ryuichiro

    2015-08-14

    Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different from sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)-SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1, and it inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome.

  17. Xanthohumol Improves Diet-induced Obesity and Fatty Liver by Suppressing Sterol Regulatory Element-binding Protein (SREBP) Activation*

    Science.gov (United States)

    Miyata, Shingo; Inoue, Jun; Shimizu, Makoto; Sato, Ryuichiro

    2015-01-01

    Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different from sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)-SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1, and it inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome. PMID:26140926

  18. Regulation of Calcium-Independent Phospholipase A2 Expression by Adrenoceptors and Sterol Regulatory Element Binding Protein-Potential Crosstalk Between Sterol and Glycerophospholipid Mediators.

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    Chew, Wee-Siong; Ong, Wei-Yi

    2016-01-01

    Calcium-independent phospholipase A2 (iPLA2) is an 85-kDa enzyme that releases docosahexaenoic acid (DHA) from glycerophospholipids. DHA can be metabolized to resolvins and neuroprotectins that have anti-inflammatory properties and effects on neural plasticity. Recent studies show an important role of prefrontal cortical iPLA2 in hippocampo-prefrontal cortical LTP and antidepressant-like effect of the norepinephrine reuptake inhibitor (NRI) antidepressant, maprotiline. In this study, we elucidated the cellular mechanisms through which stimulation of adrenergic receptors could lead to increased iPLA2 expression. Treatment of SH-SY5Y neuroblastoma cells with maprotiline, another tricyclic antidepressant with noradrenaline reuptake inhibiting properties, nortriptyline, and the adrenergic receptor agonist, phenylephrine, resulted in increased iPLA2β mRNA expression. This increase was blocked by inhibitors to alpha-1 adrenergic receptor, mitogen-activated protein (MAP) kinase or extracellular signal-regulated kinase (ERK) 1/2, and sterol regulatory element-binding protein (SREBP). Maprotiline and phenylephrine induced binding of SREBP-2 to sterol regulatory element (SRE) region on the iPLA2 promoter, as determined by electrophoretic mobility shift assay (EMSA). Together, results indicate that stimulation of adrenoreceptors causes increased iPLA2 expression via MAP kinase/ERK 1/2 and SREBP, and suggest a possible mechanism for effect of CNS noradrenaline on neural plasticity and crosstalk between sterol and glycerophospholipid mediators, that may play a role in physiological or pathophysiological processes in the brain and other organs.

  19. The flavone apigenin blocks nuclear translocation of sterol regulatory element-binding protein-2 in the hepatic cells WRL-68.

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    Wong, Tsz Yan; Lin, Shu-Mei; Leung, Lai K

    2015-06-28

    Sterol regulatory element-binding protein-2 (SREBP-2) is a pivotal transcriptional factor in cholesterol metabolism. Factors interfering with the proper functioning of SREBP-2 potentially alter plasma lipid concentrations. Consuming fruits and vegetables is associated with beneficial plasma lipid profile. The mechanism by which plant foods induce desirable lipid changes remains unclear. Apigenin, a common plant food flavonoid, was shown to modulate the nuclear translocation of SREBP-2 in the hepatic cells WRL-68 in the present study. The processing of SREBP-2 protein occurred after translation, and apigenin blocked this activation route. Further examination indicated that AMP-activated protein kinase (AMPK) was activated by the flavone, and co-administrating the AMPK-specific inhibitor compound C could release the blockage. Reporter gene assay revealed that the transactivation of sterol responsive element (SRE)-containing 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) promoter was suppressed by the flavone. Similarly, electromobility shift assay result also demonstrated a reduced DNA-binding activity on the SRE domain under the same treatment. The reduced transactivity and DNA-binding activity could be attributed to a decreased amount of SREBP-2 translocating from cytosol to nucleus as depicted by confocal microscopy. Quantitative RT-PCR assay demonstrated that the transcription of HMGCR followed the same pattern of SREBP-2 translocation. In summary, the present study showed that apigenin prevented SREBP-2 translocation and reduced the downstream gene HMGCR transcription. The minimum effective dosage should be achievable in the form of functional food consumption or dietary supplementation.

  20. Sterol Regulatory Element Binding Protein (Srb1) Is Required for Hypoxic Adaptation and Virulence in the Dimorphic Fungus Histoplasma capsulatum

    Science.gov (United States)

    DuBois, Juwen C.; Smulian, A. George

    2016-01-01

    The Histoplasma capsulatum sterol regulatory element binding protein (SREBP), Srb1 is a member of the basic helix-loop-helix (bHLH), leucine zipper DNA binding protein family of transcription factors that possess a unique tyrosine (Y) residue instead of an arginine (R) residue in the bHLH region. We have determined that Srb1 message levels increase in a time dependent manner during growth under oxygen deprivation (hypoxia). To further understand the role of Srb1 during infection and hypoxia, we silenced the gene encoding Srb1 using RNA interference (RNAi); characterized the resulting phenotype, determined its response to hypoxia, and its ability to cause disease within an infected host. Silencing of Srb1 resulted in a strain of H. capsulatum that is incapable of surviving in vitro hypoxia. We found that without complete Srb1 expression, H. capsulatum is killed by murine macrophages and avirulent in mice given a lethal dose of yeasts. Additionally, silencing Srb1 inhibited the hypoxic upregulation of other known H. capsulatum hypoxia-responsive genes (HRG), and genes that encode ergosterol biosynthetic enzymes. Consistent with these regulatory functions, Srb1 silenced H. capsulatum cells were hypersensitive to the antifungal azole drug itraconazole. These data support the theory that the H. capsulatum SREBP is critical for hypoxic adaptation and is required for H. capsulatum virulence. PMID:27711233

  1. Preventing Phosphorylation of Sterol Regulatory Element-Binding Protein 1a by MAP-Kinases Protects Mice from Fatty Liver and Visceral Obesity

    OpenAIRE

    Jorg Kotzka; Birgit Knebel; Jutta Haas; Lorena Kremer; Sylvia Jacob; Sonja Hartwig; Ulrike Nitzgen; Dirk Muller-Wieland

    2012-01-01

    The transcription factor sterol regulatory element binding protein (SREBP)-1a plays a pivotal role in lipid metabolism. Using the SREBP-1a expressing human hepatoma cell line HepG2 we have shown previously that human SREBP-1a is phosphorylated at serine 117 by ERK-mitogen-activated protein kinases (MAPK). Using a combination of cell biology and protein chemistry approach we show that SREBP-1a is also target of other MAPK-families, i.e. c-JUN N-terminal protein kinases (JNK) or p38 stress acti...

  2. Piperine Induces Hepatic Low-Density Lipoprotein Receptor Expression through Proteolytic Activation of Sterol Regulatory Element-Binding Proteins.

    Directory of Open Access Journals (Sweden)

    Ayasa Ochiai

    Full Text Available Elevated plasma low-density lipoprotein (LDL cholesterol is considered as a risk factor for atherosclerosis. Because the hepatic LDL receptor (LDLR uptakes plasma lipoproteins and lowers plasma LDL cholesterol, the activation of LDLR is a promising drug target for atherosclerosis. In the present study, we identified the naturally occurring alkaloid piperine, as an inducer of LDLR gene expression by screening the effectors of human LDLR promoter. The treatment of HepG2 cells with piperine increased LDLR expression at mRNA and protein levels and stimulated LDL uptake. Subsequent luciferase reporter gene assays revealed that the mutation of sterol regulatory element-binding protein (SREBP-binding element abolished the piperine-mediated induction of LDLR promoter activity. Further, piperine treatments increased mRNA levels of several SREBP targets and mature forms of SREBPs. However, the piperine-mediated induction of the mature forms of SREBPs was not observed in SRD-15 cells, which lack insulin-induced gene-1 (Insig-1 and Insig-2. Finally, the knockdown of SREBPs completely abolished the piperine-meditated induction of LDLR gene expression in HepG2 cells, indicating that piperine stimulates the proteolytic activation of SREBP and subsequent induction of LDLR expression and activity.

  3. Piperine Induces Hepatic Low-Density Lipoprotein Receptor Expression through Proteolytic Activation of Sterol Regulatory Element-Binding Proteins.

    Science.gov (United States)

    Ochiai, Ayasa; Miyata, Shingo; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

    2015-01-01

    Elevated plasma low-density lipoprotein (LDL) cholesterol is considered as a risk factor for atherosclerosis. Because the hepatic LDL receptor (LDLR) uptakes plasma lipoproteins and lowers plasma LDL cholesterol, the activation of LDLR is a promising drug target for atherosclerosis. In the present study, we identified the naturally occurring alkaloid piperine, as an inducer of LDLR gene expression by screening the effectors of human LDLR promoter. The treatment of HepG2 cells with piperine increased LDLR expression at mRNA and protein levels and stimulated LDL uptake. Subsequent luciferase reporter gene assays revealed that the mutation of sterol regulatory element-binding protein (SREBP)-binding element abolished the piperine-mediated induction of LDLR promoter activity. Further, piperine treatments increased mRNA levels of several SREBP targets and mature forms of SREBPs. However, the piperine-mediated induction of the mature forms of SREBPs was not observed in SRD-15 cells, which lack insulin-induced gene-1 (Insig-1) and Insig-2. Finally, the knockdown of SREBPs completely abolished the piperine-meditated induction of LDLR gene expression in HepG2 cells, indicating that piperine stimulates the proteolytic activation of SREBP and subsequent induction of LDLR expression and activity.

  4. MAP kinases Erk1/2 phosphorylate sterol regulatory element-binding protein (SREBP)-1a at serine 117 in vitro.

    Science.gov (United States)

    Roth, G; Kotzka, J; Kremer, L; Lehr, S; Lohaus, C; Meyer, H E; Krone, W; Müller-Wieland, D

    2000-10-27

    Sterol regulatory element-binding protein (SREBP)-1a is a transcription factor sensing cellular cholesterol levels and integrating gene regulatory signals mediated by MAP kinase cascades. Here we report the identification of serine 117 in SREBP-1a as the major phosphorylation site of the MAP kinases Erk1/2. This site was identified by nanoelectrospray mass spectrometry and peptide sequencing of recombinant fusion proteins phosphorylated by Erk1/2 in vitro. Serine 117 was verified as the major phosphorylation site by in vitro mutagenesis. Mutation of serine 117 to alanine abolished Erk2-mediated phosphorylation in vitro and the MAP kinase-related transcriptional activation of SREBP-1a by insulin and platelet-derived growth factor in vivo. Our data indicate that the MAP kinase-mediated effects on SREBP-1a-regulated target genes are linked to this phosphorylation site.

  5. Distribution and factors affecting adsorption of sterols in the surface sediments of Bosten Lake and Manas Lake, Xinjiang.

    Science.gov (United States)

    Liu, Jiang; Yao, Xiaorui; Lu, Jianjiang; Qiao, Xiuwen; Liu, Zilong; Li, Shanman

    2016-03-01

    This study investigated the concentrations and distribution of eight sterol compounds in the surface sediments of Bosten Lake and Manas Lake, Xinjiang, China. The ratios of sterols as diagnostic indices were used to identify pollution sources. The sediment of the two lakes was selected as an adsorbent to investigate the adsorption behaviour of sterols. Results showed that the sterols were widely distributed in the sediments of the lakes in the study areas. The total concentrations of the detected sterols in Bosten Lake and in Manas Lake were 1.584-27.897 and 2.048-18.373 μg g(-1)∙dw, respectively. In all of the sampling sites, the amount of faecal sterols was less than that of plant sterols. β-sitosterol was the dominant plant sterol with a mean concentration of 2.378 ± 2.234 μg g(-1)∙dw; cholesterol was the most abundant faecal sterol with a mean concentration of 1.060 ± 1.402 μg g(-1)∙dw. The pollution level was higher in Bosten Lake than in Manas Lake. Majority of the ratios clearly demonstrated that the contamination by human faecal sources was occurring at stations which are adjacent to residential areas and water inlets. The adsorption behaviour of sterols to sediment suggested that the sterol adsorption coefficients were reduced as temperature increased. As salinity increased, the adsorption quantity also increased. As pH increased, the sediment adsorption of sterol slightly increased because the strong alkaline solution is not conducive to the adsorption of sterols. The ratios between sterols did not change largely with the change in external factors.

  6. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    Directory of Open Access Journals (Sweden)

    Andreas Bitter

    2015-01-01

    Full Text Available Background/Aims: Sterol regulatory element-binding protein (SREBP 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human livers and primary human hepatocytes. Hepatocytes were treated with PF-429242 to inhibit the proteolytic activation of SREBP precursor protein. SREBP1a-specifc and pan-SREBP1 knock-down were performed by transfection of respective siRNAs. Lipogenic SREBP-target gene expression was analyzed by real-time RT-PCR. Results: In human liver, SREBP1a accounts for up to half of the total SREBP1 pool. Treatment with PF-429242 indicated SREBP-dependent auto-regulation of SREBP1a, which however was much weaker than of SREBP1c. SREBP1a-specifc knock-down also reduced significantly the expression of SREBP1c and of SREBP-target genes. Regarding most SREBP-target genes, simultaneous knock-down of both isoforms resulted in effects of only similar extent as SREBP1a-specific knock-down. Conclusion: We here showed that SREBP1a is significantly contributing to the human hepatic SREBP1 pool and has a share in human hepatic lipogenic gene expression.

  7. Sterol Regulatory Element Binding Protein 1a Regulates Hepatic Fatty Acid Partitioning by Activating Acetyl Coenzyme A Carboxylase 2

    OpenAIRE

    Im, Seung-Soon; Hammond, Linda E.; Yousef, Leyla; Nugas-Selby, Cherryl; Shin, Dong-Ju; Seo, Young-Kyo; Fong, Loren G.; Young, Stephen G.; Osborne, Timothy F.

    2009-01-01

    We generated a line of mice in which sterol regulatory element binding protein 1a (SREBP-1a) was specifically inactivated by insertional mutagenesis. Homozygous mutant mice were completely viable despite expressing SREBP-1a mRNA below 5% of normal, and there were minimal effects on expression of either SREBP-1c or -2. Microarray expression studies in liver, where SREBP-1a mRNA is 1/10 the level of the highly similar SREBP-1c, demonstrated that only a few genes were affected. The only downregu...

  8. Identification of Rbd2 as a candidate protease for sterol regulatory element binding protein (SREBP) cleavage in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinsil; Ha, Hye-Jeong [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Kim, Sujin [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Department of Functional Genomics, University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Choi, Ah-Reum [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Lee, Sook-Jeong [Department of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Hoe, Kwang-Lae, E-mail: kwanghoe@cnu.ac.kr [Department of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Kim, Dong-Uk, E-mail: kimdongu@kribb.re.kr [Aging Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of)

    2015-12-25

    Lipid homeostasis in mammalian cells is regulated by sterol regulatory element-binding protein (SREBP) transcription factors that are activated through sequential cleavage by Golgi Site-1 and Site-2 proteases. Fission yeast SREBP, Sre1, engages a different mechanism involving the Golgi Dsc E3 ligase complex, but it is not clearly understood exactly how Sre1 is proteolytically cleaved and activated. In this study, we screened the Schizosaccharomyces pombe non-essential haploid deletion collection to identify missing components of the Sre1 cleavage machinery. Our screen identified an additional component of the SREBP pathway required for Sre1 proteolysis named rhomboid protein 2 (Rbd2). We show that an rbd2 deletion mutant fails to grow under hypoxic and hypoxia-mimetic conditions due to lack of Sre1 activity and that this growth phenotype is rescued by Sre1N, a cleaved active form of Sre1. We found that the growth inhibition phenotype under low oxygen conditions is specific to the strain with deletion of rbd2, not any other fission yeast rhomboid-encoding genes. Our study also identified conserved residues of Rbd2 that are required for Sre1 proteolytic cleavage. All together, our results suggest that Rbd2 is a functional SREBP protease with conserved residues required for Sre1 cleavage and provide an important piece of the puzzle to understand the mechanisms for Sre1 activation and the regulation of various biological and pathological processes involving SREBPs. - Highlights: • An rbd2-deleted yeast strain shows defects in growth in response to low oxygen levels. • rbd2-deficient cells fail to generate cleaved Sre1 (Sre1N) under hypoxic conditions. • Expression of Sre1N rescues the rbd2 deletion mutant growth phenotype. • Rbd2 contains conserved residues potentially critical for catalytic activity. • Mutation of the conserved Rbd2 catalytic residues leads to defects in Sre1 cleavage.

  9. Dietary and nutritional manipulation of the nuclear transcription factors peroxisome proliferator-activated receptor and sterol regulatory element-binding proteins as a tool for reversing the primary diseases of premature death and delaying aging.

    Science.gov (United States)

    Kurtak, Karen A

    2014-04-01

    Evolution over 2.1 billion years has equipped us with a biochemical pathway that has the power to literally reverse the primary disease etiologies that have become the leading causes of death and aging in the developed world. Activation of the peroxisome proliferator-activated receptor (PPAR) pathway arrests inflammatory signaling throughout the body, reverses damage to tissues, reverses insulin resistance, and can even dissolve beta-amyloid plaque in the brain. It has played a critical role in the evolution of the metazoans and the successful migration of humans to all corners of the Earth. For two decades, various pharmaceuticals have been designed to activate the PPAR pathway but have consistently fallen short of expectations. There is nothing wrong with these drugs. The problem has been the standard "healthy" diet creating mixed signals that render the drugs ineffective. This article explores the ongoing dance between the two primary nuclear receptors that mediate gene regulation of fatty acids. It discusses their interaction with sirtuins and telomerase, optimization of their obligate heterodimers, and why manipulation of dietary and nutritional factors, like the ketogenic diet, is the most effective means of activation. These are effective tools that we can start implementing now to slow, and in some cases reverse, the diseases of aging.

  10. Curcumin up-regulates LDL receptor expression via the sterol regulatory element pathway in HepG2 cells.

    Science.gov (United States)

    Dou, Xiaobing; Fan, Chunlei; Wo, Like; Yan, Jin; Qian, Ying; Wo, Xingde

    2008-09-01

    Plasma low-density lipoprotein-cholesterol (LDL-C) is mainly taken up and cleared by the hepatocellular LDL receptor (LDL-R). LDL-R gene expression is regulated by the sterol regulatory element binding proteins (SREBPs). Previous studies have shown that curcumin reduces plasma LDL-C and has hypolipidemic and anti-atherosclerotic effects. Herein, we investigated the effect of curcumin on LDL-R expression and its molecular mechanism in HepG2 cells. Curcumin increased LDL-R expression (mRNA and protein) and the resultant uptake of DiI-LDL in a dose- and time-dependent manner. Using a GFP reporter system in a transfected HepG2/SRE-GFP cell line, we found that curcumin activated the sterol regulatory element of the LDL-R promoter. In HepG2/Insig2 cells, curcumin reversed the inhibition of LDL-R expression induced by Insig2 overexpression. These data demonstrate that curcumin increases LDL-R protein expression and uptake activity via the SREBPs pathway. These findings contribute to our further understanding of the cholesterol-lowering and anti-atherosclerotic effects of curcumin.

  11. Activation of sterol regulatory element binding protein and NLRP3 inflammasome in atherosclerotic lesion development in diabetic pigs.

    Directory of Open Access Journals (Sweden)

    Yu Li

    Full Text Available BACKGROUND: Aberrantly elevated sterol regulatory element binding protein (SREBP, the lipogenic transcription factor, contributes to the development of fatty liver and insulin resistance in animals. Our recent studies have discovered that AMP-activated protein kinase (AMPK phosphorylates SREBP at Ser-327 and inhibits its activity, represses SREBP-dependent lipogenesis, and thereby ameliorates hepatic steatosis and atherosclerosis in insulin-resistant LDLR(-/- mice. Chronic inflammation and activation of NLRP3 inflammasome have been implicated in atherosclerosis and fatty liver disease. However, whether SREBP is involved in vascular lipid accumulation and inflammation in atherosclerosis remains largely unknown. PRINCIPAL FINDINGS: The preclinical study with aortic pouch biopsy specimens from humans with atherosclerosis and diabetes shows intense immunostaining for SREBP-1 and the inflammatory marker VCAM-1 in atherosclerotic plaques. The cleavage processing of SREBP-1 and -2 and expression of their target genes are increased in the well-established porcine model of diabetes and atherosclerosis, which develops human-like, complex atherosclerotic plaques. Immunostaining analysis indicates an elevation in SREBP-1 that is primarily localized in endothelial cells and in infiltrated macrophages within fatty streaks, fibrous caps with necrotic cores, and cholesterol crystals in advanced lesions. Moreover, concomitant suppression of NAD-dependent deacetylase SIRT1 and AMPK is observed in atherosclerotic pigs, which leads to the proteolytic activation of SREBP-1 by diminishing the deacetylation and Ser-372 phosphorylation of SREBP-1. Aberrantly elevated NLRP3 inflammasome markers are evidenced by increased expression of inflammasome components including NLPR3, ASC, and IL-1β. The increase in SREBP-1 activity and IL-1β production in lesions is associated with vascular inflammation and endothelial dysfunction in atherosclerotic pig aorta, as demonstrated

  12. Sterol regulation of acetyl coenzyme A carboxylase: a mechanism for coordinate control of cellular lipid.

    OpenAIRE

    Lopez, J.M.; Bennett, M K; Sanchez, H B; Rosenfeld, J M; Osborne, T E

    1996-01-01

    Transcription from the housekeeping promoter for the acetyl coenzyme A carboxylase (ACC) gene, which encodes the rate-controlling enzyme of fatty acid biosynthesis, is shown to be regulated by cellular sterol levels through novel binding sites for the sterol-sensitive sterol regulatory element binding protein (SREBP)-1 transcription factor. The position of the SREBP sites relative to those for the ubiquitous auxiliary transcription factor Sp1 is reminiscent of that previously described for th...

  13. Regulation of the CDP-choline pathway by sterol regulatory element binding proteins involves transcriptional and post-transcriptional mechanisms.

    Science.gov (United States)

    Ridgway, Neale D; Lagace, Thomas A

    2003-06-15

    The synthesis of phosphatidylcholine (PtdCho) by the CDP-choline pathway is under the control of the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT). Sterol regulatory element binding proteins (SREBPs) have been proposed to regulate CCT at the transcriptional level, or via the synthesis of lipid activators or substrates of the CDP-choline pathway. To assess the contributions of these two mechanisms, we examined CCTalpha expression and PtdCho synthesis by the CDP-choline pathway in cholesterol and fatty acid auxotrophic CHO M19 cells inducibly expressing constitutively active nuclear forms of SREBP1a or SREBP2. Induction of either SREBP resulted in increased expression of mRNAs for sterol-regulated genes, elevated fatty acid and cholesterol synthesis (>10-50-fold) and increased PtdCho synthesis (2-fold). CCTalpha mRNA was increased 2-fold by enforced expression of SREBP1a or SREBP2. The resultant increase in CCTalpha protein and activity (2-fold) was restricted primarily to the soluble fraction of cells, and increased CCTalpha activity in vivo was not detected. Inhibition of the synthesis of fatty acids or their CoA esters by cerulenin or triacsin C respectively following SREBP induction effectively blocked the accompanying elevation in PtdCho synthesis. Thus PtdCho synthesis was driven by increased synthesis of fatty acids or a product thereof. These data show that transcriptional activation of CCTalpha is modest relative to that of other SREBP-regulated genes, and that stimulation of PtdCho synthesis by SREBPs in CHO cells is due primarily to increased fatty acid synthesis.

  14. Plant Sterols: Diversity, Biosynthesis, and Physiological Functions.

    Science.gov (United States)

    Valitova, J N; Sulkarnayeva, A G; Minibayeva, F V

    2016-08-01

    Sterols, which are isoprenoid derivatives, are structural components of biological membranes. Special attention is now being given not only to their structure and function, but also to their regulatory roles in plants. Plant sterols have diverse composition; they exist as free sterols, sterol esters with higher fatty acids, sterol glycosides, and acylsterol glycosides, which are absent in animal cells. This diversity of types of phytosterols determines a wide spectrum of functions they play in plant life. Sterols are precursors of a group of plant hormones, the brassinosteroids, which regulate plant growth and development. Furthermore, sterols participate in transmembrane signal transduction by forming lipid microdomains. The predominant sterols in plants are β-sitosterol, campesterol, and stigmasterol. These sterols differ in the presence of a methyl or an ethyl group in the side chain at the 24th carbon atom and are named methylsterols or ethylsterols, respectively. The balance between 24-methylsterols and 24-ethylsterols is specific for individual plant species. The present review focuses on the key stages of plant sterol biosynthesis that determine the ratios between the different types of sterols, and the crosstalk between the sterol and sphingolipid pathways. The main enzymes involved in plant sterol biosynthesis are 3-hydroxy-3-methylglutaryl-CoA reductase, C24-sterol methyltransferase, and C22-sterol desaturase. These enzymes are responsible for maintaining the optimal balance between sterols. Regulation of the ratios between the different types of sterols and sterols/sphingolipids can be of crucial importance in the responses of plants to stresses.

  15. Effects of retinoic acid and hydrogen peroxide on sterol regulatory element-binding protein-1a activation during adipogenic differentiation of 3T3-L1 cells

    OpenAIRE

    Eldaim, Mabrouk A. Abd; Okamatsu-Ogura, Yuko; Terao, Akira; Kimura, Kazuhiro

    2010-01-01

    Both retinoic acid (RA) and oxidative stress (H2O2) increased transcription and cleavage of membrane-bound sterol regulatory element-binding protein (SREBP)-1, leading to enhanced transcription of fatty acid synthase (FAS) in hepatoma cells. On the other hand, RA and H2O2 decreased and increased lipogenesis in adipocytes, respectively, although roles of SREBP-1 activation in these effects remain to be elucidated. To elucidate its involvement, we examined the activation of SREBP...

  16. Sterols and squalene in apricot (Prunus armeniaca L.) kernel oils: the variety as a key factor.

    Science.gov (United States)

    Rudzińska, Magdalena; Górnaś, Paweł; Raczyk, Marianna; Soliven, Arianne

    2017-01-01

    The profile of sterols and squalene content in oils recovered from the kernels of 15 apricot (Prunus armeniaca L.) varieties were investigated. Nine sterols (campesterol, β-sitosterol, Δ5-avenasterol, 24-methylene-cycloartanol, cholesterol, gramisterol, Δ7-stigmasterol, Δ7-avenasterol and citrostadienol) were identified in apricot kernel oils. The β-sitosterol was the predominant sterol in each cultivar and consisted of 76-86% of the total detected sterols. The content of total sterols and squalene were significantly affected by the variety and ranged between 215.7-973.6 and 12.6-43.9 mg/100 g of oil, respectively.

  17. Regulation of steroid 5-{alpha} reductase type 2 (Srd5a2) by sterol regulatory element binding proteins and statin

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Young-Kyo [Department of Molecular Biology and Biochemistry, 3244 McGaugh Hall, University of California, UC Irvine, Irvine, CA 92697-3900 (United States); Zhu, Bing [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0144 (United States); Jeon, Tae-Il [Department of Molecular Biology and Biochemistry, 3244 McGaugh Hall, University of California, UC Irvine, Irvine, CA 92697-3900 (United States); Osborne, Timothy F., E-mail: tfosborn@uci.edu [Department of Molecular Biology and Biochemistry, 3244 McGaugh Hall, University of California, UC Irvine, Irvine, CA 92697-3900 (United States)

    2009-11-01

    In this study, we show that sterol regulatory element binding proteins (SREBPs) regulate expression of Srd5a2, an enzyme that catalyzes the irreversible conversion of testosterone to dihydroxytestosterone in the male reproductive tract and is highly expressed in androgen-sensitive tissues such as the prostate and skin. We show that Srd5a2 is induced in livers and prostate from mice fed a chow diet supplemented with lovastatin plus ezitimibe (L/E), which increases the activity of nuclear SREBP-2. The three fold increase in Srd5a2 mRNA mediated by L/E treatment was accompanied by the induction of SREBP-2 binding to the Srd5a2 promoter detected by a ChIP-chip assay in liver. We identified a SREBP-2 responsive region within the first 300 upstream bases of the mouse Srd5a2 promoter by co-transfection assays which contain a site that bound SREBP-2 in vitro by an EMSA. Srd5a2 protein was also induced in cells over-expressing SREBP-2 in culture. The induction of Srd5a2 through SREBP-2 provides a mechanistic explanation for why even though statin therapy is effective in reducing cholesterol levels in treating hypercholesterolemia it does not compromise androgen production in clinical studies.

  18. Sterol regulatory element-binding protein-1 determines plasma remnant lipoproteins and accelerates atherosclerosis in low-density lipoprotein receptor-deficient mice.

    Science.gov (United States)

    Karasawa, Tadayoshi; Takahashi, Akimitsu; Saito, Ryo; Sekiya, Motohiro; Igarashi, Masaki; Iwasaki, Hitoshi; Miyahara, Shoko; Koyasu, Saori; Nakagawa, Yoshimi; Ishii, Kiyoaki; Matsuzaka, Takashi; Kobayashi, Kazuto; Yahagi, Naoya; Takekoshi, Kazuhiro; Sone, Hirohito; Yatoh, Shigeru; Suzuki, Hiroaki; Yamada, Nobuhiro; Shimano, Hitoshi

    2011-08-01

    Sterol regulatory element-binding protein-1 (SREBP-1) is nutritionally regulated and is known to be a key transcription factor regulating lipogenic enzymes. The goal of this study was to evaluate the roles of SREBP-1 in dyslipidemia and atherosclerosis. Transgenic mice that overexpress SREBP-1c in the liver and SREBP-1-deficient mice were crossed with low-density lipoprotein receptor (LDLR)-deficient mice, and the plasma lipids and atherosclerosis were analyzed. Hepatic SREBP-1c overexpression in LDLR-deficient mice caused postprandial hypertriglyceridemia, increased very-low-density lipoprotein (VLDL) cholesterol, and decreased high-density lipoprotein cholesterol in plasma, which resulted in accelerated aortic atheroma formation. Conversely, absence of SREBP-1 suppressed Western diet-induced hyperlipidemia in LDLR-deficient mice and ameliorated atherosclerosis. In contrast, bone marrow-specific SREBP-1 deficiency did not alter the development of atherosclerosis. The size of nascent VLDL particles secreted from the liver was increased in SREBP-1c transgenic mice and reduced in SREBP-1-deficient mice, accompanied by upregulation and downregulation of phospholipid transfer protein expression, respectively. Hepatic SREBP-1c determines plasma triglycerides and remnant cholesterol and contributes to atherosclerosis in hyperlipidemic states. Hepatic SREBP-1c also regulates the size of nascent VLDL particles.

  19. β-Hydroxybutyrate Facilitates Fatty Acids Synthesis Mediated by Sterol Regulatory Element-Binding Protein1 in Bovine Mammary Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Min Zhang

    2015-11-01

    Full Text Available Background/Aims: In dairy cows, β-hydroxybutyrate (BHBA is utilized as precursors of de novo synthesized fatty acids in mammary gland. Ketotic cows are characterized by excessive negative energy balance (NEB, which can further increase the blood BHBA concentration. Sterol regulatory element-binding protein1 (SREBP1 and cell death-inducing DNA fragmentation factor-alpha-like effector α (Cidea play crucial roles in lipid synthesis. Therefore, we hypothesized that BHBA could stimulate SREBP1/Cidea pathway to increase milk fat synthesis in bovine mammary epithelial cells. Methods: Bovine mammary epithelial cells were treated with different concentrations of BHBA and transfected with adenovirus to silence SREBP1 expression. The effects of BHBA on the lipid synthesis in bovine mammary epithelial cells were investigated. Results: The results showed that BHBA could significantly increase the expression of SREBP1, fatty acid synthase (FAS, acetyl-CoA carboxylase α (ACC-α, Cidea and diacylglycerol transferase-1 (DGAT-1, as well as the triglycerides (TG content in bovine mammary epithelial cells. BHBA treatment also increased the transfer of mature SREBP1 to nucleus compared with control group. However, SREBP1 silencing could significantly down-regulate the overexpression of FAS, ACC-α, Cidea and DGAT-1, as well as TG content induced by BHBA. Conclusion: The present data indicate that BHBA can significantly increase TG secretion mediated by SREBP1 in bovine mammary epithelial cells.

  20. Heat Shock Protein 90 Modulates Lipid Homeostasis by Regulating the Stability and Function of Sterol Regulatory Element-binding Protein (SREBP) and SREBP Cleavage-activating Protein.

    Science.gov (United States)

    Kuan, Yen-Chou; Hashidume, Tsutomu; Shibata, Takahiro; Uchida, Koji; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

    2017-02-17

    Sterol regulatory element-binding proteins (SREBPs) are the key transcription factors that modulate lipid biosynthesis. SREBPs are synthesized as endoplasmic reticulum-bound precursors that require proteolytic activation in the Golgi apparatus. The stability and maturation of precursor SREBPs depend on their binding to SREBP cleavage-activating protein (SCAP), which escorts the SCAP-SREBP complex to the Golgi apparatus. In this study, we identified heat shock protein (HSP) 90 as a novel SREBP regulator that binds to and stabilizes SCAP-SREBP. In HepG2 cells, HSP90 inhibition led to proteasome-dependent degradation of SCAP-SREBP, which resulted in the down-regulation of SREBP target genes and the reduction in intracellular triglyceride and cholesterol levels. We also demonstrated in vivo that HSP90 inhibition decreased SCAP-SREBP protein, down-regulated SREBP target genes, and reduced lipids levels in mouse livers. We propose that HSP90 plays an indispensable role in SREBP regulation by stabilizing the SCAP-SREBP complex, facilitating the activation of SREBP to maintain lipids homeostasis.

  1. Yeast sterol regulatory element-binding protein (SREBP) cleavage requires Cdc48 and Dsc5, a ubiquitin regulatory X domain-containing subunit of the Golgi Dsc E3 ligase.

    Science.gov (United States)

    Stewart, Emerson V; Lloyd, S Julie-Ann; Burg, John S; Nwosu, Christine C; Lintner, Robert E; Daza, Riza; Russ, Carsten; Ponchner, Karen; Nusbaum, Chad; Espenshade, Peter J

    2012-01-01

    Schizosaccharomyces pombe Sre1 is a membrane-bound transcription factor that controls adaptation to hypoxia. Like its mammalian homolog, sterol regulatory element-binding protein (SREBP), Sre1 activation requires release from the membrane. However, in fission yeast, this release occurs through a strikingly different mechanism that requires the Golgi Dsc E3 ubiquitin ligase complex and the proteasome. The mechanistic details of Sre1 cleavage, including the link between the Dsc E3 ligase complex and proteasome, are not well understood. Here, we present results of a genetic selection designed to identify additional components required for Sre1 cleavage. From the selection, we identified two new components of the fission yeast SREBP pathway: Dsc5 and Cdc48. The AAA (ATPase associated with diverse cellular activities) ATPase Cdc48 and Dsc5, a ubiquitin regulatory X domain-containing protein, interact with known Dsc complex components and are required for SREBP cleavage. These findings provide a mechanistic link between the Dsc E3 ligase complex and the proteasome in SREBP cleavage and add to a growing list of similarities between the Dsc E3 ligase and membrane E3 ligases involved in endoplasmic reticulum-associated degradation.

  2. Preventing phosphorylation of sterol regulatory element-binding protein 1a by MAP-kinases protects mice from fatty liver and visceral obesity.

    Science.gov (United States)

    Kotzka, Jorg; Knebel, Birgit; Haas, Jutta; Kremer, Lorena; Jacob, Sylvia; Hartwig, Sonja; Nitzgen, Ulrike; Muller-Wieland, Dirk

    2012-01-01

    The transcription factor sterol regulatory element binding protein (SREBP)-1a plays a pivotal role in lipid metabolism. Using the SREBP-1a expressing human hepatoma cell line HepG2 we have shown previously that human SREBP-1a is phosphorylated at serine 117 by ERK-mitogen-activated protein kinases (MAPK). Using a combination of cell biology and protein chemistry approach we show that SREBP-1a is also target of other MAPK-families, i.e. c-JUN N-terminal protein kinases (JNK) or p38 stress activated MAP kinases. Serine 117 is also the major phosphorylation site in SREBP-1a for JNK. In contrast to that the major phosphorylation sites of p38 MAPK family are serine 63 and threonine 426. Functional analyses reveal that phosphorylation of SREBP-1a does not alter protein/DNA interaction. The identified phosphorylation sites are specific for both kinase families also in cellular context. To provide direct evidence that phosphorylation of SREBP-1a is a regulatory principle of biological and clinical relevance, we generated transgenic mice expressing mature transcriptionally active N-terminal domain of human SREBP-1a variant lacking all identified phosphorylaton sites designed as alb-SREBP-1aΔP and wild type SREBP-1a designed as alb-SREBP-1a liver specific under control of the albumin promoter and a liver specific enhancer. In contrast to alb-SREBP-1a mice the phosphorylation-deficient mice develop no enlarged fatty livers under normocaloric conditions. Phenotypical examination reveales a massive accumulation of adipose tissue in alb-SREBP-1a but not in the phosphorylation deficient alb-SREBP-1aΔP mice. Moreover, preventing phosphorylation of SREBP-1a protects mice also from dyslipidemia. In conclusion, phosphorylation of SREBP-1a by ERK, JNK and p38 MAPK-families resembles a biological principle and plays a significant role, in vivo.

  3. Preventing phosphorylation of sterol regulatory element-binding protein 1a by MAP-kinases protects mice from fatty liver and visceral obesity.

    Directory of Open Access Journals (Sweden)

    Jorg Kotzka

    Full Text Available The transcription factor sterol regulatory element binding protein (SREBP-1a plays a pivotal role in lipid metabolism. Using the SREBP-1a expressing human hepatoma cell line HepG2 we have shown previously that human SREBP-1a is phosphorylated at serine 117 by ERK-mitogen-activated protein kinases (MAPK. Using a combination of cell biology and protein chemistry approach we show that SREBP-1a is also target of other MAPK-families, i.e. c-JUN N-terminal protein kinases (JNK or p38 stress activated MAP kinases. Serine 117 is also the major phosphorylation site in SREBP-1a for JNK. In contrast to that the major phosphorylation sites of p38 MAPK family are serine 63 and threonine 426. Functional analyses reveal that phosphorylation of SREBP-1a does not alter protein/DNA interaction. The identified phosphorylation sites are specific for both kinase families also in cellular context. To provide direct evidence that phosphorylation of SREBP-1a is a regulatory principle of biological and clinical relevance, we generated transgenic mice expressing mature transcriptionally active N-terminal domain of human SREBP-1a variant lacking all identified phosphorylaton sites designed as alb-SREBP-1aΔP and wild type SREBP-1a designed as alb-SREBP-1a liver specific under control of the albumin promoter and a liver specific enhancer. In contrast to alb-SREBP-1a mice the phosphorylation-deficient mice develop no enlarged fatty livers under normocaloric conditions. Phenotypical examination reveales a massive accumulation of adipose tissue in alb-SREBP-1a but not in the phosphorylation deficient alb-SREBP-1aΔP mice. Moreover, preventing phosphorylation of SREBP-1a protects mice also from dyslipidemia. In conclusion, phosphorylation of SREBP-1a by ERK, JNK and p38 MAPK-families resembles a biological principle and plays a significant role, in vivo.

  4. Sterol regulatory element-binding proteins are regulators of the rat thyroid peroxidase gene in thyroid cells.

    Directory of Open Access Journals (Sweden)

    Christine Rauer

    Full Text Available Sterol regulatory element-binding proteins (SREBPs-1c and -2, which were initially discovered as master transcriptional regulators of lipid biosynthesis and uptake, were recently identified as novel transcriptional regulators of the sodium-iodide symporter gene in the thyroid, which is essential for thyroid hormone synthesis. Based on this observation that SREBPs play a role for thyroid hormone synthesis, we hypothesized that another gene involved in thyroid hormone synthesis, the thyroid peroxidase (TPO gene, is also a target of SREBP-1c and -2. Thyroid epithelial cells treated with 25-hydroxycholesterol, which is known to inhibit SREBP activation, had about 50% decreased mRNA levels of TPO. Similarly, the mRNA level of TPO was reduced by about 50% in response to siRNA mediated knockdown of both, SREBP-1 and SREBP-2. Reporter gene assays revealed that overexpression of active SREBP-1c and -2 causes a strong transcriptional activation of the rat TPO gene, which was localized to an approximately 80 bp region in the intron 1 of the rat TPO gene. In vitro- and in vivo-binding of both, SREBP-1c and SREBP-2, to this region in the rat TPO gene could be demonstrated using gel-shift assays and chromatin immunoprecipitation. Mutation analysis of the 80 bp region of rat TPO intron 1 revealed two isolated and two overlapping SREBP-binding elements from which one, the overlapping SRE+609/InvSRE+614, was shown to be functional in reporter gene assays. In connection with recent findings that the rat NIS gene is also a SREBP target gene in the thyroid, the present findings suggest that SREBPs may be possible novel targets for pharmacological modulation of thyroid hormone synthesis.

  5. Regulation of Sterol Biosynthesis in the Human Fungal Pathogen Aspergillus fumigatus: Opportunities for Therapeutic Development

    Science.gov (United States)

    Dhingra, Sourabh; Cramer, Robert A.

    2017-01-01

    Sterols are a major component of eukaryotic cell membranes. For human fungal infections caused by the filamentous fungus Aspergillus fumigatus, antifungal drugs that target sterol biosynthesis and/or function remain the standard of care. Yet, an understanding of A. fumigatus sterol biosynthesis regulatory mechanisms remains an under developed therapeutic target. The critical role of sterol biosynthesis regulation and its interactions with clinically relevant azole drugs is highlighted by the basic helix loop helix (bHLH) class of transcription factors known as Sterol Regulatory Element Binding Proteins (SREBPs). SREBPs regulate transcription of key ergosterol biosynthesis genes in fungi including A. fumigatus. In addition, other emerging regulatory pathways and target genes involved in sterol biosynthesis and drug interactions provide additional opportunities including the unfolded protein response, iron responsive transcriptional networks, and chaperone proteins such as Hsp90. Thus, targeting molecular pathways critical for sterol biosynthesis regulation presents an opportunity to improve therapeutic options for the collection of diseases termed aspergillosis. This mini-review summarizes our current understanding of sterol biosynthesis regulation with a focus on mechanisms of transcriptional regulation by the SREBP family of transcription factors. PMID:28203225

  6. Tlr4-mutant mice are resistant to acute alcohol-induced sterol-regulatory element binding protein activation and hepatic lipid accumulation

    Science.gov (United States)

    Zhang, Zhi-Hui; Liu, Xiao-Qian; Zhang, Cheng; He, Wei; Wang, Hua; Chen, Yuan-Hua; Liu, Xiao-Jing; Chen, Xi; Xu, De-Xiang

    2016-01-01

    Previous studies demonstrated that acute alcohol intoxication caused hepatic lipid accumulation. The present study showed that acute alcohol intoxication caused hepatic lipid accumulation in Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic sterol-regulatory element binding protein (SREBP)-1, a transcription factor regulating fatty acid and triglyceride (TG) synthesis, was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic Fas, Acc, Scd-1 and Dgat-2, the key genes for fatty acid and TG synthesis, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Additional experiment showed that hepatic MyD88 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic NF-κB was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Moreover, hepatic GSH content was reduced and hepatic MDA level was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic CYP2E1 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic p67phox and gp91phox, two NADPH oxidase subunits, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin-trapping agent, protected against alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. In conclusion, Tlr4-mutant mice are resistant to acute alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. PMID:27627966

  7. Subunit architecture of the Golgi Dsc E3 ligase required for sterol regulatory element-binding protein (SREBP) cleavage in fission yeast.

    Science.gov (United States)

    Lloyd, S Julie-Ann; Raychaudhuri, Sumana; Espenshade, Peter J

    2013-07-19

    The membrane-bound sterol regulatory element-binding protein (SREBP) transcription factors regulate lipogenesis in mammalian cells and are activated through sequential cleavage by the Golgi-localized Site-1 and Site-2 proteases. The mechanism of fission yeast SREBP cleavage is less well defined and, in contrast, requires the Golgi-localized Dsc E3 ligase complex. The Dsc E3 ligase consists of five integral membrane subunits, Dsc1 through Dsc5, and resembles membrane E3 ligases that function in endoplasmic reticulum-associated degradation. Using immunoprecipitation assays and blue native electrophoresis, we determined the subunit architecture for the complex of Dsc1 through Dsc5, showing that the Dsc proteins form subcomplexes and display defined connectivity. Dsc2 is a rhomboid pseudoprotease family member homologous to mammalian UBAC2 and a central component of the Dsc E3 ligase. We identified conservation in the architecture of the Dsc E3 ligase and the multisubunit E3 ligase gp78 in mammals. Specifically, Dsc1-Dsc2-Dsc5 forms a complex resembling gp78-UBAC2-UBXD8. Further characterization of Dsc2 revealed that its C-terminal UBA domain can bind to ubiquitin chains but that the Dsc2 UBA domain is not essential for yeast SREBP cleavage. Based on the ability of rhomboid superfamily members to bind transmembrane proteins, we speculate that Dsc2 functions in SREBP recognition and binding. Homologs of Dsc1 through Dsc4 are required for SREBP cleavage and virulence in the human opportunistic pathogen Aspergillus fumigatus. Thus, these studies advance our organizational understanding of multisubunit E3 ligases involved in endoplasmic reticulum-associated degradation and fungal pathogenesis.

  8. Sterol regulation of human fatty acid synthase promoter I requires nuclear factor-Y- and Sp-1-binding sites.

    Science.gov (United States)

    Xiong, S; Chirala, S S; Wakil, S J

    2000-04-11

    To understand cholesterol-mediated regulation of human fatty acid synthase promoter I, we tested various 5'-deletion constructs of promoter I-luciferase reporter gene constructs in HepG2 cells. The reporter gene constructs that contained only the Sp-1-binding site (nucleotides -82 to -74) and the two tandem sterol regulatory elements (SREs; nucleotides -63 to -46) did not respond to cholesterol. Only the reporter gene constructs containing a nuclear factor-Y (NF-Y) sequence, the CCAAT sequence (nucleotides -90 to -86), an Sp-1 sequence, and the two tandem SREs responded to cholesterol. The NF-Y-binding site, therefore, is essential for cholesterol response. Mutating the SREs or the NF-Y site and inserting 4 bp between the Sp-1- and NF-Y-binding sites both resulted in a minimal cholesterol response of the reporter genes. Electrophoretic mobility-shift assays using anti-SRE-binding protein (SREBP) and anti-NF-Ya antibodies confirmed that these SREs and the NF-Y site bind the respective factors. We also identified a second Sp-1 site located between nucleotides -40 and -30 that can substitute for the mutated Sp-1 site located between nucleotides -82 and -74. The reporter gene expression of the wild-type promoter and the Sp-1 site (nucleotides -82 to -74) mutant promoter was similar when SREBP1a [the N-terminal domain of SREBP (amino acids 1-520)] was constitutively overexpressed, suggesting that Sp-1 recruits SREBP to the SREs. Under the same conditions, an NF-Y site mutation resulted in significant loss of reporter gene expression, suggesting that NF-Y is required to activate the cholesterol response.

  9. The gene encoding acyl-CoA-binding protein is subject to metabolic regulation by both sterol regulatory element-binding protein and peroxisome proliferator-activated receptor alpha in hepatocytes

    DEFF Research Database (Denmark)

    Sandberg, Maria B; Bloksgaard, Maria; Duran-Sandoval, Daniel

    2005-01-01

    gene in hepatocytes. Members of the SREBP family activate the rat ACBP gene through binding sites for SREBP and the auxiliary factors Sp1 and nuclear factor Y in the proximal promoter. In addition, we show that ACBP is a peroxisome proliferator-activated receptor (PPAR) alpha target gene in cultured...... observation that ACBP expression in rodent liver is down-regulated by fasting, and we show that insulin but not glucose is the inducer of ACBP expression in primary rat hepatocytes. In keeping with the regulation by insulin, we show that ACBP is a sterol regulatory element-binding protein 1c (SREBP-1c) target...... hepatocytes and is induced in the liver by fibrates in a PPARalpha-dependent manner. Thus, ACBP is a dual PPARalpha and SREBP-1c target gene in hepatocytes. Fasting leads to reduced activity of SREBP but increased activity of PPARalpha in hepatocytes, and in keeping with ACBP being a dual target gene, we show...

  10. Dsc E3 ligase localization to the Golgi requires the ATPase Cdc48 and cofactor Ufd1 for activation of Sterol Regulatory Element-binding Protein in fission yeast.

    Science.gov (United States)

    Burr, Risa; Ribbens, Diedre; Raychaudhuri, Sumana; Stewart, Emerson V; Ho, Jason; Espenshade, Peter J

    2017-08-18

    Sterol regulatory element-binding proteins (SREBPs) in the fission yeast Schizosaccharomyces pombe regulate lipid homeostasis and the hypoxic response under conditions of low sterol or oxygen availability. SREBPs are cleaved in the Golgi through the combined action of the Dsc E3 ligase complex, the rhomboid protease Rbd2, and the essential ATPases Associated with diverse cellular Activities (AAA+) ATPase Cdc48. The soluble SREBP N-terminal transcription factor domain is then released in the cytosol to enter the nucleus and regulate gene expression. Previously, we reported that Cdc48 binding to Rbd2 is required for Rbd2-mediated SREBP cleavage. Here, using affinity chromatography and mass spectrometry experiments, we identified Cdc48-binding proteins in S. pombe, generating a list of many previously unknown potential Cdc48 binding partners. We show that the established Cdc48 cofactor Ufd1 is required for SREBP cleavage but does not interact with the Cdc48-Rbd2 complex. Cdc48-Ufd1 is instead required at a step prior to Rbd2 function, during Golgi localization of the Dsc E3 ligase complex. Together, these findings demonstrate that two distinct Cdc48 complexes - Cdc48-Ufd1 and Cdc48-Rbd2 - are required for SREBP activation and low-oxygen adaptation in S. pombe. Copyright © 2017, The American Society for Biochemistry and Molecular Biology.

  11. 三种植物甾醇调控SRE元件和3T3-L1细胞脂肪化活性的作用%Effects of Three Plant Sterols on Activity of Sterol Regulatory Element and Adipogenesis of 3T3L-1

    Institute of Scientific and Technical Information of China (English)

    陈彦光; 张弦; 刘健

    2013-01-01

    [目的]为了研究植物甾醇对脂质代谢的调控作用.[方法]利用所构建的SRE荧光素酶活性测定系统,体外考察了豆甾醇、β-谷甾醇和菜油甾醇3种常见的植物甾醇对SRE元件的调控活性.[结果]植物甾醇能够增强SRE元件活性.植物甾醇也可以增加3T3-L1细胞的脂肪化作用.[结论]植物甾醇可能正调控脂质的合成.%[Objective] The research aimed to study the regulating effect of plant sterol on lipid metabolism.[Method] Luciferase reporter vector pGL3-basic that contained one or three sterol regulatory element (SRE) was transfected into HepG2,and luciferase activity of three plant sterols (stigmasterol,β-sitosterol and campesterol) was analyzed.[Result] The plant sterols had positive regulator of SRE.And plant sterols could increase adipogenesis of 3T3L-1.[Conclusion] Plant sterols could increase adipogenesis by increasing SRE activity.

  12. Sterol regulatory element binding protein (SREBP)-1 expression in brain is affected by age but not by hormones or metabolic changes.

    Science.gov (United States)

    Okamoto, Kenjirou; Kakuma, Tetsuya; Fukuchi, Satoshi; Masaki, Takayuki; Sakata, Toshiie; Yoshimatsu, Hironobu

    2006-04-07

    Sterol regulatory element binding protein (SREBP)-1 is a membrane-bound transcription factor that regulates the expression of several genes involved in cellular fatty acid synthesis in the peripheral tissues, including liver. Although SREBP-1 is expressed in brain, little is known about its function. The aim of the present study was to clarify the characteristics of SREBP-1 mRNA expression in rat brain under various nutritional and hormonal conditions. In genetically obese (fa/fa) Zucker rats, expression of SREBP-1 mRNA was greater in liver than in hypothalamus or cerebrum compared to the lean littermates of these rats. Fasting for 45 h and refeeding for 3 h did not affect expression in brains of Wistar rats of SREBP-1 mRNA or the mRNAs of lipogenic enzymes that are targets of SREBP-1, i.e., fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC). Infusion of 2.0 mIU insulin or 3.0 microg leptin into the third cerebroventricle did not affect SREBP-1 mRNA expression in either hypothalamus or cerebrum. SREBP-1 mRNA expression in brains of transgenic mice that overexpressed leptin did not differ from that of wild-type mice. However, we observed a unique age-related alteration in SREBP-1 mRNA expression in brains of Sprague-Dawley rats. Specifically, SREBP-1 mRNA expression increased between 1 and 20 months of age, while there was no such change in the expression of FAS or ACC. This raises the possibility that increased SREBP-1 expression secondary to aging-related decline of polyunsaturated fatty acid (PUFA) might compensate for the reduction of FAS expression in brain. These findings suggest that the expression of SREBP-1 and downstream lipogenic enzymes in brain is probably not regulated by peripheral nutritional conditions or humoral factors. Aging-related changes in SREBP-1 mRNA expression may be involved in developmental changes in brain lipid metabolism.

  13. Multiple Functions of Sterols in Yeast Endocytosis

    Science.gov (United States)

    Heese-Peck, Antje; Pichler, Harald; Zanolari, Bettina; Watanabe, Reika; Daum, Günther; Riezman, Howard

    2002-01-01

    Sterols are essential factors for endocytosis in animals and yeast. To investigate the sterol structural requirements for yeast endocytosis, we created a variety of ergΔ mutants, each accumulating a distinct set of sterols different from ergosterol. Mutant erg2Δerg6Δ and erg3Δerg6Δ cells exhibit a strong internalization defect of the α-factor receptor (Ste2p). Specific sterol structures are necessary for pheromone-dependent receptor hyperphosphorylation, a prerequisite for internalization. The lack of phosphorylation is not due to a defect in Ste2p localization or in ligand–receptor interaction. Contrary to most known endocytic factors, sterols seem to function in internalization independently of actin. Furthermore, sterol structures are required at a postinternalization step of endocytosis. ergΔ cells were able to take up the membrane marker FM4-64, but exhibited defects in FM4-64 movement through endosomal compartments to the vacuole. Therefore, there are at least two roles for sterols in endocytosis. Based on sterol analysis, the sterol structural requirements for these two processes were different, suggesting that sterols may have distinct functions at different places in the endocytic pathway. Interestingly, sterol structures unable to support endocytosis allowed transport of the glycosylphosphatidylinositol-anchored protein Gas1p from the endoplasmic reticulum to Golgi compartment. PMID:12181337

  14. Matrix metalloproteinase-2 mediates a mechanism of metabolic cardioprotection consisting of negative regulation of the sterol regulatory element-binding protein-2/3-hydroxy-3-methylglutaryl-CoA reductase pathway in the heart.

    Science.gov (United States)

    Wang, Xiang; Berry, Evan; Hernandez-Anzaldo, Samuel; Takawale, Abhijit; Kassiri, Zamaneh; Fernandez-Patron, Carlos

    2015-04-01

    Previously, we reported that cardiac matrix metalloproteinase (MMP)-2 is upregulated in hypertensive mice. How MMP-2 affects the development of cardiac disease is unclear. Here, we report that MMP-2 protects from hypertensive cardiac disease. In mice infused with angiotensin II, the lack of MMP-2 (Mmp2(-/-)) did not affect the severity of the hypertension but caused cardiac hypertrophy to develop earlier and to a greater extent versus wild-type (Mmp2(+/+)) mice, as measured by heart weight:body weight ratio and upregulation of hypertrophy and fibrosis markers. We further found numerous metabolic and inflammatory gene expression abnormalities in the left ventricle of Mmp2(-/-) mice. Interestingly, Mmp2(-/-) mice expressed greater amounts of sterol regulatory element-binding protein-2 and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (a target of sterol regulatory element-binding protein-2-mediated transcription and rate limiting enzyme in cholesterol and isoprenoids biosynthesis) in addition to markers of inflammation including chemokines of the C-C motif ligand family. We focused on the functionally related genes for sterol regulatory binding protein-2 and 3-hydroxy-3-methylglutaryl-coenzyme A reductase. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, lovastatin, attenuated angiotensin II-induced cardiac hypertrophy and fibrosis in Mmp2(-/-) and wild-type (Mmp2(+/+)) mice, with Mmp2(-/-) mice showing resistance to cardioprotection by lovastatin. MMP-2 deficiency predisposes to cardiac dysfunction as well as metabolic and inflammatory gene expression dysregulation. This complex phenotype is, at least in part, because of the cardiac sterol regulatory element-binding protein-2/3-hydroxy-3-methylglutaryl-coenzyme A reductase pathway being upregulated in MMP-2 deficiency.

  15. Lipid extract of Nostoc commune var. sphaeroides Kutzing, a blue-green alga, inhibits the activation of sterol regulatory element binding proteins in HepG2 cells.

    Science.gov (United States)

    Rasmussen, Heather E; Blobaum, Kara R; Park, Young-Ki; Ehlers, Sarah J; Lu, Fan; Lee, Ji-Young

    2008-03-01

    Nostoc commune var. sphaeroides Kützing (N. commune), a blue-green alga, has been used as both a food ingredient and in medicine for centuries. To determine the effect of N. commune on cholesterol metabolism, N. commune lipid extract was incubated at increasing concentrations (25-100 mg/L) with HepG2 cells, a human hepatoma cell line. The addition of N. commune lipid extract markedly reduced mRNA abundance of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and LDL receptor (LDLR) (P commune lipid extract confirmed the inhibitory role of N. commune in cholesterol synthesis (P commune lipid extract, expression of sterol regulatory element binding protein 2 (SREBP-2) was assessed. Whereas mRNA for SREBP-2 remained unchanged, SREBP-2 mature protein was reduced by N. commune (P commune lipid extract also decreased SREBP-1 mature protein by approximately 30% (P commune lipid extract inhibits the maturation process of both SREBP-1 and -2, resulting in a decrease in expression of genes involved in cholesterol and fatty acid metabolism.

  16. Dietary fiber prevents obesity-related liver lipotoxicity by modulating sterol-regulatory element binding protein pathway in C57BL/6J mice fed a high-fat/cholesterol diet.

    Science.gov (United States)

    Han, Shufen; Jiao, Jun; Zhang, Wei; Xu, Jiaying; Wan, Zhongxiao; Zhang, Weiguo; Gao, Xiaoran; Qin, Liqiang

    2015-10-29

    Adequate intake of dietary fibers has proven metabolic and cardiovascular benefits, molecular mechanisms remain still limited. This study was aimed to investigate the effects of cereal dietary fiber on obesity-related liver lipotoxicity in C57BL/6J mice fed a high-fat/cholesterol (HFC) diet and underlying mechanism. Forty-eight adult male C57BL/6J mice were randomly given a reference chow diet, or a high fat/cholesterol (HFC) diet supplemented with or without oat fiber or wheat bran fiber for 24 weeks. Our results showed mice fed oat or wheat bran fiber exhibited lower weight gain, lipid profiles and insulin resistance, compared with HFC diet. The two cereal dietary fibers potently decreased protein expressions of sterol regulatory element binding protein-1 and key factors involved in lipogenesis, including fatty acid synthase and acetyl-CoA carboxylase in target tissues. At molecular level, the two cereal dietary fibers augmented protein expressions of peroxisome proliferator-activated receptor alpha and gamma, liver X receptor alpha, and ATP-binding cassette transporter A1 in target tissues. Our findings indicated that cereal dietary fiber supplementation abrogated obesity-related liver lipotoxicity and dyslipidemia in C57BL/6J mice fed a HFC diet. In addition, the efficacy of oat fiber is greater than wheat bran fiber in normalizing these metabolic disorders and pathological profiles.

  17. Progesterone stimulates adipocyte determination and differentiation 1/sterol regulatory element-binding protein 1c gene expression. potential mechanism for the lipogenic effect of progesterone in adipose tissue.

    Science.gov (United States)

    Lacasa, D; Le Liepvre, X; Ferre, P; Dugail, I

    2001-04-13

    Fatty acid synthase (FAS), a nutritionally regulated lipogenic enzyme, is transcriptionally controlled by ADD1/SREBP1c (adipocyte determination and differentiation 1/sterol regulatory element-binding protein 1c), through insulin-mediated stimulation of ADD1/SREBP1c expression. Progesterone exerts lipogenic effects on adipocytes, and FAS is highly induced in breast tumor cell lines upon progesterone treatment. We show here that progesterone up-regulates ADD1/SREBP1c expression in the MCF7 breast cancer cell line and the primary cultured preadipocyte from rat parametrial adipose tissue. In MCF7, progesterone induced ADD1/SREBP1c and Metallothionein II (a well known progesterone-regulated gene) mRNAs, with comparable potency. In preadipocytes, progesterone increased ADD1/SREBP1c mRNA dose-dependently, but not SREBP1a or SREBP2. Run-on experiments demonstrated that progesterone action on ADD1/SREBP1c was primarily at the transcriptional level. The membrane-bound and mature nuclear forms of ADD1/SREBP1 protein accumulated in preadipocytes cultured with progesterone, and FAS induction could be abolished by adenovirus-mediated overexpression of a dominant negative form of ADD1/SREBP1 in these cells. Finally, in the presence of insulin, progesterone was unable to up-regulate ADD1/SREBP1c mRNA in preadipocytes, whereas its effect was restored after 24 h of insulin deprivation. Together these results demonstrate that ADD1/SREBP1c is controlled by progesterone, which, like insulin, acts by increasing ADD1/SREBP1c gene transcription. This provides a potential mechanism for the lipogenic actions of progesterone on adipose tissue.

  18. Central leptin regulates total ceramide content and sterol regulatory element binding protein-1C proteolytic maturation in rat white adipose tissue.

    Science.gov (United States)

    Bonzón-Kulichenko, Elena; Schwudke, Dominik; Gallardo, Nilda; Moltó, Eduardo; Fernández-Agulló, Teresa; Shevchenko, Andrej; Andrés, Antonio

    2009-01-01

    Obesity and type 2 diabetes are associated with insulin and leptin resistance, and increased ceramide contents in target tissues. Because the adipose tissue has become a central focus in these diseases, and leptin-induced increases in insulin sensitivity may be related to effects of leptin on lipid metabolism, we investigated herein whether central leptin was able to regulate total ceramide levels and the expression of enzymes involved in ceramide metabolism in rat white adipose tissue (WAT). After 7 d central leptin treatment, the total content of ceramides was analyzed by quantitative shotgun lipidomics mass spectrometry. The effects of leptin on the expression of several enzymes of the sphingolipid metabolism, sterol regulatory element binding protein (SREBP)-1c, and insulin-induced gene 1 (INSIG-1) in this tissue were studied. Total ceramide levels were also determined after surgical WAT denervation. Central leptin infusion significantly decreased both total ceramide content and the long-chain fatty acid ceramide species in WAT. Concomitant with these results, leptin decreased the mRNA levels of enzymes involved in de novo ceramide synthesis (SPT-1, LASS2, LASS4) and ceramide production from sphingomyelin (SMPD-1/2). The mRNA levels of enzymes of ceramide degradation (Asah1/2) and utilization (sphingomyelin synthase, ceramide kinase, glycosyl-ceramide synthase, GM3 synthase) were also down-regulated. Ceramide-lowering effects of central leptin were prevented by local autonomic nervous system denervation of WAT. Finally, central leptin treatment markedly increased INSIG-1 mRNA expression and impaired SREBP-1c activation in epididymal WAT. These observations indicate that in vivo central leptin, acting through the autonomic nervous system, regulates total ceramide levels and SREBP-1c proteolytic maturation in WAT, probably contributing to improve the overall insulin sensitivity.

  19. The Hepatitis C Virus-induced NLRP3 Inflammasome Activates the Sterol Regulatory Element-binding Protein (SREBP) and Regulates Lipid Metabolism.

    Science.gov (United States)

    McRae, Steven; Iqbal, Jawed; Sarkar-Dutta, Mehuli; Lane, Samantha; Nagaraj, Abhiram; Ali, Naushad; Waris, Gulam

    2016-02-12

    Hepatitis C virus (HCV) relies on host lipids and lipid droplets for replication and morphogenesis. The accumulation of lipid droplets in infected hepatocytes manifests as hepatosteatosis, a common pathology observed in chronic hepatitis C patients. One way by which HCV promotes the accumulation of intracellular lipids is through enhancing de novo lipogenesis by activating the sterol regulatory element-binding proteins (SREBPs). In general, activation of SREBPs occurs during cholesterol depletion. Interestingly, during HCV infection, the activation of SREBPs occurs under normal cholesterol levels, but the underlying mechanisms are still elusive. Our previous study has demonstrated the activation of the inflammasome complex in HCV-infected human hepatoma cells. In this study, we elucidate the potential link between chronic hepatitis C-associated inflammation and alteration of lipid homeostasis in infected cells. Our results reveal that the HCV-activated NLRP3 inflammasome is required for the up-regulation of lipogenic genes such as 3-hydroxy-3-methylglutaryl-coenzyme A synthase, fatty acid synthase, and stearoyl-CoA desaturase. Using pharmacological inhibitors and siRNA against the inflammasome components (NLRP3, apoptosis-associated speck-like protein containing a CARD, and caspase-1), we further show that the activation of the NLRP3 inflammasome plays a critical role in lipid droplet formation. NLRP3 inflammasome activation in HCV-infected cells enables caspase-1-mediated degradation of insulin-induced gene proteins. This subsequently leads to the transport of the SREBP cleavage-activating protein·SREBP complex from the endoplasmic reticulum to the Golgi, followed by proteolytic activation of SREBPs by S1P and S2P in the Golgi. Typically, inflammasome activation leads to viral clearance. Paradoxically, here we demonstrate how HCV exploits the NLRP3 inflammasome to activate SREBPs and host lipid metabolism, leading to liver disease pathogenesis associated with

  20. Sterol Regulatory Element-Binding Protein-1c Regulates Inflammasome Activation in Gingival Fibroblasts Infected with High-Glucose-Treated Porphyromonas gingivalis

    Science.gov (United States)

    Kuo, Hsing-Chun; Chang, Li-Ching; Chen, Te-Chuan; Lee, Ko-Chao; Lee, Kam-Fai; Chen, Cheng-Nan; Yu, Hong-Ren

    2016-01-01

    Background: Porphyromonas gingivalis is a major bacterial species implicated in the progression of periodontal disease, which is recognized as a common complication of diabetes. The interleukin (IL)-1β, processed by the NLR family pyrin domain containing 3 (NLRP3) inflammasome, has been identified as a target for pathogenic infection of the inflammatory response. However, the effect of P. gingivalis in a high-glucose situation in the modulation of inflammasome activation in human gingival fibroblasts (HGFs) is not well-understood. Methods: P. gingivalis strain CCUG25226 was used to study the mechanisms underlying the regulation of HGF NLRP3 expression by the infection of high-glucose-treated P. gingivalis (HGPg). Results: HGF infection with HGPg increases the expression of IL-1β and NLRP3. We further demonstrated that the upregulation of sterol regulatory element-binding protein (SREBP)-1c by activation of the Akt and p70S6K pathways is critical for HGPg-induced NLRP3 expression. We showed that the inhibition of Janus kinase 2 (JAK2) blocks the Akt- and p70S6K-mediated SREBP-1c, NLRP3, and IL-1β expression. The effect of HGPg on HGF signaling and NLRP3 expression is mediated by β1 integrin. In addition, gingival tissues from diabetic patients with periodontal disease exhibited higher NLRP3 and SREBP-1c expression. Conclusions: Our findings identify the molecular pathways underlying HGPg-dependent NLRP3 inflammasome expression in HGFs, providing insight into the effect of P. gingivalis invasion in HGFs. PMID:28083517

  1. Insect growth regulatory effects of some extracts and sterols from Myrtillocactus geometrizans (Cactaceae) against Spodoptera frugiperda and Tenebrio molitor.

    Science.gov (United States)

    Céspedes, Carlos L; Salazar, J Rodrigo; Martínez, Mariano; Aranda, Eduardo

    2005-10-01

    A methanol extract from the roots and aerial parts of Myrtillocactus geometrizans (Cactaceae) yielded peniocerol 1, macdougallin 2, and chichipegenin 3. The natural products 1, 2 their mixtures, MeOH and CH(2)Cl(2) extracts showed insecticidal and insect growth regulatory activity against fall armyworm [Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae)], an important insect pest of corn, and [Tenebrio molitor (Coleoptera)], a pest of stored grains in Mexico. The most active compounds were 1, 2, and a mixture (M(2)) of 1 and 2 (6:4). All these extracts, compounds and the mixture had insect growth regulating (IGR) activity between 5.0 and 50.0 ppm and insecticidal effects between 50 and 300 ppm in diets. The extracts were insecticidal to larvae, with lethal doses between 100 and 200 ppm. These compounds appear to have selective effects on the pre-emergence metabolism of Coleoptera, because in all treatments of the larvae of T. molitor, pupation were shortened and this process show precociousness in relation to controls. In contrast to S. frugiperda larvae, onset of pupation was noticeably delayed. Emergence in both cases was drastically diminished. In both pupae and in the few adults that were able to emerge, many deformations were observed. The results of these assays indicated that the compounds were more active than other known natural insect growth inhibitors such as gedunin and methanol extracts of Cedrela salvadorensis and Yucca periculosa. Peniocerol, macdougallin and chichipegenin, as well as mixtures of these substances, may be useful as natural insecticidal agents.

  2. A novel sterol regulatory element-binding protein gene (sreA identified in penicillium digitatum is required for prochloraz resistance, full virulence and erg11 (cyp51 regulation.

    Directory of Open Access Journals (Sweden)

    Jing Liu

    Full Text Available Penicillium digitatum is the most destructive postharvest pathogen of citrus fruits, causing fruit decay and economic loss. Additionally, control of the disease is further complicated by the emergence of drug-resistant strains due to the extensive use of triazole antifungal drugs. In this work, an orthologus gene encoding a putative sterol regulatory element-binding protein (SREBP was identified in the genome of P. digitatum and named sreA. The putative SreA protein contains a conserved domain of unknown function (DUF2014 at its carboxyl terminus and a helix-loop-helix (HLH leucine zipper DNA binding domain at its amino terminus, domains that are functionally associated with SREBP transcription factors. The deletion of sreA (ΔsreA in a prochloraz-resistant strain (PdHS-F6 by Agrobacterium tumefaciens-mediated transformation led to increased susceptibility to prochloraz and a significantly lower EC50 value compared with the HS-F6 wild-type or complementation strain (COsreA. A virulence assay showed that the ΔsreA strain was defective in virulence towards citrus fruits, while the complementation of sreA could restore the virulence to a large extent. Further analysis by quantitative real-time PCR demonstrated that prochloraz-induced expression of cyp51A and cyp51B in PdHS-F6 was completely abolished in the ΔsreA strain. These results demonstrate that sreA is a critical transcription factor gene required for prochloraz resistance and full virulence in P. digitatum and is involved in the regulation of cyp51 expression.

  3. A novel sterol regulatory element-binding protein gene (sreA) identified in penicillium digitatum is required for prochloraz resistance, full virulence and erg11 (cyp51) regulation.

    Science.gov (United States)

    Liu, Jing; Yuan, Yongze; Wu, Zhi; Li, Na; Chen, Yuanlei; Qin, Tingting; Geng, Hui; Xiong, Li; Liu, Deli

    2015-01-01

    Penicillium digitatum is the most destructive postharvest pathogen of citrus fruits, causing fruit decay and economic loss. Additionally, control of the disease is further complicated by the emergence of drug-resistant strains due to the extensive use of triazole antifungal drugs. In this work, an orthologus gene encoding a putative sterol regulatory element-binding protein (SREBP) was identified in the genome of P. digitatum and named sreA. The putative SreA protein contains a conserved domain of unknown function (DUF2014) at its carboxyl terminus and a helix-loop-helix (HLH) leucine zipper DNA binding domain at its amino terminus, domains that are functionally associated with SREBP transcription factors. The deletion of sreA (ΔsreA) in a prochloraz-resistant strain (PdHS-F6) by Agrobacterium tumefaciens-mediated transformation led to increased susceptibility to prochloraz and a significantly lower EC50 value compared with the HS-F6 wild-type or complementation strain (COsreA). A virulence assay showed that the ΔsreA strain was defective in virulence towards citrus fruits, while the complementation of sreA could restore the virulence to a large extent. Further analysis by quantitative real-time PCR demonstrated that prochloraz-induced expression of cyp51A and cyp51B in PdHS-F6 was completely abolished in the ΔsreA strain. These results demonstrate that sreA is a critical transcription factor gene required for prochloraz resistance and full virulence in P. digitatum and is involved in the regulation of cyp51 expression.

  4. Effect of a plant sterol, fish oil and B vitamin combination on cardiovascular risk factors in hypercholesterolemic children and adolescents: a pilot study

    Directory of Open Access Journals (Sweden)

    Garaiova Iveta

    2013-01-01

    Full Text Available Abstract Background Assessment of cardiovascular disease (CVD risk factors can predict clinical manifestations of atherosclerosis in adulthood. In this pilot study with hypercholesterolemic children and adolescents, we investigated the effects of a combination of plant sterols, fish oil and B vitamins on the levels of four independent risk factors for CVD; LDL-cholesterol, triacylglycerols, C-reactive protein and homocysteine. Methods Twenty five participants (mean age 16 y, BMI 23 kg/m2 received daily for a period of 16 weeks an emulsified preparation comprising plant sterols esters (1300 mg, fish oil (providing 1000 mg eicosapentaenoic acid (EPA plus docosahexaenoic acid (DHA and vitamins B12 (50 μg, B6 (2.5 mg, folic acid (800 μg and coenzyme Q10 (3 mg. Atherogenic and inflammatory risk factors, plasma lipophilic vitamins, provitamins and fatty acids were measured at baseline, week 8 and 16. Results The serum total cholesterol, LDL- cholesterol, VLDL-cholesterol, subfractions LDL-2, IDL-1, IDL-2 and plasma homocysteine levels were significantly reduced at the end of the intervention period (pp Conclusions Daily intake of a combination of plant sterols, fish oil and B vitamins may modulate the lipid profile of hypercholesterolemic children and adolescents. Trial registration Current Controlled Trials ISRCTN89549017

  5. Direct inhibition of the ubiquitin-proteasome pathway by ester bond-containing green tea polyphenols is associated with increased expression of sterol regulatory element-binding protein 2 and LDL receptor.

    Science.gov (United States)

    Kuhn, Deborah J; Burns, Audrey C; Kazi, Aslamuzzaman; Dou, Q Ping

    2004-06-01

    Green tea has been shown to lower plasma cholesterol, associated with up-regulation of the low-density lipoprotein receptor (LDLR) although the responsible molecular mechanism is unknown. Previously, we reported that ester bond-containing green tea polyphenols (GTPs), such as (-)-epigallocatechin-3-gallate [(-)-EGCG], potently inhibit the tumor cellular proteasome activity, which may contribute to the cancer-preventative effect of green tea. In the current study, we hypothesize that the proteasome is a heart disease-associated molecular target of GTPs. We have shown that ester bond-containing GTPs, including (-)-EGCG, potently inhibit the proteasomal activity in intact hepatocellular carcinoma HepG2 and cervical carcinoma HeLa cells, as evident by accumulation of ubiquitinated proteins and three natural proteasome targets (p27, IkappaB-alpha and Bax). (-)-EGCG selectively inhibits the chymotrypsin-like, but not trypsin-like, activity of the proteasome. Associated with proteasome inhibition by ester bond-containing GTPs, there was a significant, time- and concentration-dependent increase in levels of the cleaved, activated, but not the precursor, form of sterol regulatory element-binding protein 2 (SREBP-2), an essential factor for LDLR transcription. Subsequently, LDL receptor expression was increased dramatically in HepG2 and HeLa cells treated with (-)-EGCG. Our results suggest that ester bond-containing GTPs inhibit ubiquitin/proteasome-mediated degradation of the active SREBP-2, resulting in up-regulation of LDLR. This identified molecular mechanism may be related to the previously reported cholesterol-lowering and heart disease-preventative effects of green tea.

  6. Orchard factors associated with resistance and cross resistance to sterol demethylation inhibitor fungicides in populations of Venturia inaequalis from Pennsylvania.

    Science.gov (United States)

    Pfeufer, Emily E; Ngugi, Henry K

    2012-03-01

    Orchard management practices, such as destroying of overwintered inoculum and limiting the number of fungicide applications, are often recommended as tactics for slowing the development of resistance to sterol demethylation-inhibitor (DMI) fungicides in populations of Venturia inaequalis. However, there is little quantitative evidence relating the use of such practices to levels of resistance in orchards. The aim of this study was to evaluate the sensitivity of V. inaequalis isolates from Pennsylvania to DMI fungicides, and to identify orchard management factors related to the incidence of resistant isolates. In total, 644 single-spore V. inaequalis cultures obtained from 20 apple orchards in 2008 or 2009 were tested for sensitivity to myclobutanil, fenbuconazole, or difenoconazole. Growers provided management history of the sampled plots. Widespread shifts toward resistance to the three fungicides were noted, with mean effective concentration for 50% inhibition (EC(50)) values of 2.136, 0.786, and 0.187 μg/ml for myclobutanil, fenbuconazole, and difenoconazole, respectively. Cross resistance to the three fungicides was documented in high correlation (Spearman's r > 0.6) between mean EC(50) values for 14 orchards. Based on a 0.5-μg/ml threshold, 66 and 26% of isolates were resistant to myclobutanil and fenbuconazole, respectively, and 22% were cross resistant to the two fungicides. A significant between-year shift toward increased resistance was noted in two of three orchards surveyed in both years. Failure to use dormant copper sprays, older trees, larger orchards, orchards with ≤10 cultivars, and application of >4 DMI sprays were positively correlated (0.0001 resistant isolates. Isolates from orchards with >4 DMI sprays were four times as likely to be resistant to fenbuconazole (odds ratio = 4.57; P = 0.015). Isolates from orchards without dormant copper sprays were twice as likely to be cross-shifted toward resistance to all three fungicides (odds ratio = 1

  7. Sterol requirements in Drosophila melanogaster

    OpenAIRE

    Almeida de Carvalho, Maria Joao

    2009-01-01

    Sterol is an abundant component of eukaryotic cell membranes and is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila is an excellent model system in which to study functional requirements for membrane sterol because, although it does not synthesize sterol, it nevertheless requires sterols to complete development. Moreover, Drosophila normally incorporates sterols into cell membranes. Thus, dietary sterol depletion can be used to ...

  8. Sterol metabolism of insects

    NARCIS (Netherlands)

    Ritter, F.J.; Wientjens, W.H.J.M.

    1967-01-01

    This article surveys the present knowledge of the sterol metabolism of insects. It is emphasized that a high degree of purity of the dietary sterols and the climination of the influence of symbionts are essential to present ambiguity in interpreting results. It is pointed out that a sharp distinctio

  9. STARD4 Membrane Interactions and Sterol Binding.

    Science.gov (United States)

    Iaea, David B; Dikiy, Igor; Kiburu, Irene; Eliezer, David; Maxfield, Frederick R

    2015-08-01

    The steroidogenic acute regulatory protein-related lipid transfer (START) domain family is defined by a conserved 210-amino acid sequence that folds into an α/β helix-grip structure. Members of this protein family bind a variety of ligands, including cholesterol, phospholipids, sphingolipids, and bile acids, with putative roles in nonvesicular lipid transport, metabolism, and cell signaling. Among the soluble START proteins, STARD4 is expressed in most tissues and has previously been shown to transfer sterol, but the molecular mechanisms of membrane interaction and sterol binding remain unclear. In this work, we use biochemical techniques to characterize regions of STARD4 and determine their role in membrane interaction and sterol binding. Our results show that STARD4 interacts with anionic membranes through a surface-exposed basic patch and that introducing a mutation (L124D) into the Omega-1 (Ω1) loop, which covers the sterol binding pocket, attenuates sterol transfer activity. To gain insight into the attenuating mechanism of the L124D mutation, we conducted structural and biophysical studies of wild-type and L124D STARD4. These studies show that the L124D mutation reduces the conformational flexibility of the protein, resulting in a diminished level of membrane interaction and sterol transfer. These studies also reveal that the C-terminal α-helix, and not the Ω1 loop, partitions into the membrane bilayer. On the basis of these observations, we propose a model of STARD4 membrane interaction and sterol binding and release that requires dynamic movement of both the Ω1 loop and membrane insertion of the C-terminal α-helix.

  10. Sterol Synthesis in Diverse Bacteria.

    Science.gov (United States)

    Wei, Jeremy H; Yin, Xinchi; Welander, Paula V

    2016-01-01

    Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc), which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from five phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia) and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult. Some bacteria

  11. Oleanolic Acid Diminishes Liquid Fructose-Induced Fatty Liver in Rats: Role of Modulation of Hepatic Sterol Regulatory Element-Binding Protein-1c-Mediated Expression of Genes Responsible for De Novo Fatty Acid Synthesis

    Directory of Open Access Journals (Sweden)

    Changjin Liu

    2013-01-01

    Full Text Available Oleanolic acid (OA, contained in more than 1620 plants and as an aglycone precursor for naturally occurred and synthesized triterpenoid saponins, is used in China for liver disorders in humans. However, the underlying liver-protecting mechanisms remain largely unknown. Here, we found that treatment of rats with OA (25 mg/kg/day, gavage, once daily over 10 weeks diminished liquid fructose-induced excess hepatic triglyceride accumulation without effect on total energy intake. Attenuation of the increased vacuolization and Oil Red O staining area was evident on histological examination of liver in OA-treated rats. Hepatic gene expression profile demonstrated that OA suppressed fructose-stimulated overexpression of sterol regulatory element-binding protein-(SREBP- 1/1c mRNA and nuclear protein. In accord, overexpression of SREBP-1c-responsive genes responsible for fatty acid synthesis was also downregulated. In contrast, overexpressed nuclear protein of carbohydrate response element-binding protein and its target genes liver pyruvate kinase and microsomal triglyceride transfer protein were not altered. Additionally, OA did not affect expression of peroxisome proliferator-activated receptor-gamma- and -alpha and their target genes. It is concluded that modulation of hepatic SREBP-1c-mediated expression of the genes responsible for de novo fatty acid synthesis plays a pivotal role in OA-elicited diminishment of fructose-induced fatty liver in rats.

  12. Effects of Stearoyl-CoA Desaturase 1 and Sterol Regulatory Element Binding Protein Gene Polymorphisms on Milk Production, Composition and Coagulation Properties of Individual Milk of Brown Swiss Cows

    Directory of Open Access Journals (Sweden)

    Alice Maurmayr

    2011-10-01

    Full Text Available Associations between stearoyl-CoA desaturase (SCD and sterol regulatory element binding protein (SREBP-1 gene polymorphisms and milk production, composition (fat, protein, and casein content, acidity (pH and titratable acidity and coagulation properties (MCP, namely rennet coagulation time (RCT, min and curd firmness (a30, mm were investigated on individual Brown Swiss milk. A total of 294 cows from 16 herds and progeny of 15 sires were milk-sampled once. Th e additive effects of SCD and SREBP-1 genotypes on the aforementioned traits were analyzed through Bayesian linear models. The SCD gene was associated with protein content, casein content and a30. Lower protein, casein and a30 was observed for milk yielded by SCD V than A cows, whereas for other traits the effect was trivial. Animals carrying the L allele of SREBP-1 showed higher fat content than animals carrying the S allele. These results suggest a possible use of these loci in gene-assisted selection programs for the improvement of milk quality traits and MCP in Brown Swiss cattle, although large scale studies in different breeds are required.

  13. Effects of Stearoyl-CoA Desaturase 1 and Sterol Regulatory Element Binding Protein Gene Polymorphisms on Milk Production, Composition and Coagulation Properties of Individual Milk of Brown Swiss Cows

    Directory of Open Access Journals (Sweden)

    Alice Maurmayr

    2011-09-01

    Full Text Available Associations between stearoyl-CoA desaturase (SCD and sterol regulatory element binding protein (SREBP-1 gene polymorphisms and milk production, composition (fat, protein, and casein content, acidity (pH and titratable acidity and coagulation properties (MCP, namely rennet coagulation time (RCT, min and curd firmness (a30, mm were investigated on individual Brown Swiss milk. A total of 294 cows from 16 herds and progeny of 15 sires were milk-sampled once. Th e additive effects of SCD and SREBP-1 genotypes on the aforementioned traits were analyzed through Bayesian linear models. The SCD gene was associated with protein content, casein content and a30. Lower protein, casein and a30 was observed for milk yielded by SCD V than A cows, whereas for other traits the effect was trivial. Animals carrying the L allele of SREBP-1 showed higher fat content than animals carrying the S allele. These results suggest a possible use of these loci in gene-assisted selection programs for the improvement of milk quality traits and MCP in Brown Swiss cattle, although large scale studies in different breeds are required.

  14. Confined housing system increased abdominal and subcutaneous fat deposition and gene expressions of carbohydrate response element-binding protein and sterol regulatory element-binding protein 1 in chicken.

    Science.gov (United States)

    Li, Q; Zhao, X L; Gilbert, E R; Liu, Y P; Wang, Y; Qiu, M H; Zhu, Q

    2015-02-06

    Free-range production system is increasingly being used in poultry breeding and feed production in many countries. The objective of the current experiment was to evaluate the effects of different raising systems on fat-related traits and mRNA levels of liver lipogenesis genes in Erlang Mountainous chicken. Each of 10 birds (91 day old) from caged, indoor-floor housed, and free-range housing systems was slaughtered, and fat-related traits, live body weight (BW), subcutaneous fat thickness (SFT), abdominal fat weight (AFW), abdominal fat percentage (AFP), and intramuscular fat content were determined. The mRNA levels of liver X receptor α, carbohydrate response element-binding protein (ChREBP), sterol regulatory element-binding protein-1 (SREBP1), and fatty acid synthase were detected. The caged chicken exhibited significantly higher BW, SFT, and AFW than those of free-ranged chicken (P caged chicken, while the lowest level was found in free-ranged chicken. Association analysis indicated that there were significant (P caged chicken was probably induced by increased gene expression of ChREBP and SREBP1 in the liver.

  15. The Hypoxic Regulator of Sterol Synthesis Nro1 Is a Nuclear Import Adaptor

    Energy Technology Data Exchange (ETDEWEB)

    T Yeh; C Lee; L Amzel; P Espenshade; M Bianchet

    2011-12-31

    Fission yeast protein Sre1, the homolog of the mammalian sterol regulatory element-binding protein (SREBP), is a hypoxic transcription factor required for sterol homeostasis and low-oxygen growth. Nro1 regulates the stability of the N-terminal transcription factor domain of Sre1 (Sre1N) by inhibiting the action of the prolyl 4-hydroxylase-like Ofd1 in an oxygen-dependent manner. The crystal structure of Nro1 determined at 2.2 {angstrom} resolution shows an all-{alpha}-helical fold that can be divided into two domains: a small N-terminal domain, and a larger C-terminal HEAT-repeat domain. Follow-up studies showed that Nro1 defines a new class of nuclear import adaptor that functions both in Ofd1 nuclear localization and in the oxygen-dependent inhibition of Ofd1 to control the hypoxic response.

  16. Non-cholesterol sterols and cholesterol metabolism in sitosterolemia.

    Science.gov (United States)

    Othman, Rgia A; Myrie, Semone B; Jones, Peter J H

    2013-12-01

    Sitosterolemia (STSL) is a rare autosomal recessive disease, manifested by extremely elevated plant sterols (PS) in plasma and tissue, leading to xanthoma and premature atherosclerotic disease. Therapeutic approaches include limiting PS intake, interrupting enterohepatic circulation of bile acid using bile acid binding resins such as cholestyramine, and/or ileal bypass, and inhibiting intestinal sterol absorption by ezetimibe (EZE). The objective of this review is to evaluate sterol metabolism in STSL and the impact of the currently available treatments on sterol trafficking in this disease. The role of PS in initiation of xanthomas and premature atherosclerosis is also discussed. Blocking sterols absorption with EZE has revolutionized STSL patient treatment as it reduces circulating levels of non-cholesterol sterols in STSL. However, none of the available treatments including EZE have normalized plasma PS concentrations. Future studies are needed to: (i) explore where cholesterol and non-cholesterol sterols accumulate, (ii) assess to what extent these sterols in tissues can be mobilized after blocking their absorption, and (iii) define the factors governing sterol flux.

  17. Structure and regulatory function of plant transcription factors

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The expression of inducible genes in plants is regulated byspecific transcription factors at the transcriptional level. A typical transcription factor usually contains a DNA-binding domain, a transcription regulation domain, a dimerization site and a nuclear localization domain. These functional domains define the characteristic, localization and regulatory role of a transcription factor. Transcription factors recognize and bind to specific cis-acting elements or interact with other proteins, and then activate or repress the transcription of target genes by their functional domains. In recent years, elucidation on the structure and function of transcription factors has become an important subject in plant molecular biology.

  18. An expansive human regulatory lexicon encoded in transcription factor footprints.

    Science.gov (United States)

    Neph, Shane; Vierstra, Jeff; Stergachis, Andrew B; Reynolds, Alex P; Haugen, Eric; Vernot, Benjamin; Thurman, Robert E; John, Sam; Sandstrom, Richard; Johnson, Audra K; Maurano, Matthew T; Humbert, Richard; Rynes, Eric; Wang, Hao; Vong, Shinny; Lee, Kristen; Bates, Daniel; Diegel, Morgan; Roach, Vaughn; Dunn, Douglas; Neri, Jun; Schafer, Anthony; Hansen, R Scott; Kutyavin, Tanya; Giste, Erika; Weaver, Molly; Canfield, Theresa; Sabo, Peter; Zhang, Miaohua; Balasundaram, Gayathri; Byron, Rachel; MacCoss, Michael J; Akey, Joshua M; Bender, M A; Groudine, Mark; Kaul, Rajinder; Stamatoyannopoulos, John A

    2012-09-06

    Regulatory factor binding to genomic DNA protects the underlying sequence from cleavage by DNase I, leaving nucleotide-resolution footprints. Using genomic DNase I footprinting across 41 diverse cell and tissue types, we detected 45 million transcription factor occupancy events within regulatory regions, representing differential binding to 8.4 million distinct short sequence elements. Here we show that this small genomic sequence compartment, roughly twice the size of the exome, encodes an expansive repertoire of conserved recognition sequences for DNA-binding proteins that nearly doubles the size of the human cis-regulatory lexicon. We find that genetic variants affecting allelic chromatin states are concentrated in footprints, and that these elements are preferentially sheltered from DNA methylation. High-resolution DNase I cleavage patterns mirror nucleotide-level evolutionary conservation and track the crystallographic topography of protein-DNA interfaces, indicating that transcription factor structure has been evolutionarily imprinted on the human genome sequence. We identify a stereotyped 50-base-pair footprint that precisely defines the site of transcript origination within thousands of human promoters. Finally, we describe a large collection of novel regulatory factor recognition motifs that are highly conserved in both sequence and function, and exhibit cell-selective occupancy patterns that closely parallel major regulators of development, differentiation and pluripotency.

  19. Structural studies on meiosis-activating sterols and structurally related compounds : potential ligands of the FF-MAS receptor

    NARCIS (Netherlands)

    Boer, D.R.

    2001-01-01

    Meiosis Activating Sterols (MAS) are key regulatory factors in the meiotic cell cycle. Two compounds in this family, Follicular Fluid-MAS (FF-MAS or 4,4-dimethyl-5a-cholest-8,14,24-triene-3b-ol) and Testicular-MAS (T-MAS or 4,4-dimethyl-5a-cholest-8,14-diene-3b-ol), have been isolated and

  20. Simultaneous Effects of Light Intensity and Phosphorus Supply on the Sterol Content of Phytoplankton

    OpenAIRE

    Maike Piepho; Dominik Martin-Creuzburg; Alexander Wacker

    2010-01-01

    Sterol profiles of microalgae and their change with environmental conditions are of great interest in ecological food web research and taxonomic studies alike. Here, we investigated effects of light intensity and phosphorus supply on the sterol content of phytoplankton and assessed potential interactive effects of these important environmental factors on the sterol composition of algae. We identified sterol contents of four common phytoplankton genera, Scenedesmus, Chlamydomonas, Cryptomonas ...

  1. Regulatory coordination of clustered microRNAs based on microRNA-transcription factor regulatory network

    Directory of Open Access Journals (Sweden)

    Wang Jin

    2011-12-01

    Full Text Available Abstract Background MicroRNA (miRNA is a class of small RNAs of ~22nt which play essential roles in many crucial biological processes and numerous human diseases at post-transcriptional level of gene expression. It has been revealed that miRNA genes tend to be clustered, and the miRNAs organized into one cluster are usually transcribed coordinately. This implies a coordinated regulation mode exerted by clustered miRNAs. However, how the clustered miRNAs coordinate their regulations on large scale gene expression is still unclear. Results We constructed the miRNA-transcription factor regulatory network that contains the interactions between transcription factors (TFs, miRNAs and non-TF protein-coding genes, and made a genome-wide study on the regulatory coordination of clustered miRNAs. We found that there are two types of miRNA clusters, i.e. homo-clusters that contain miRNAs of the same family and hetero-clusters that contain miRNAs of various families. In general, the homo-clustered as well as the hetero-clustered miRNAs both exhibit coordinated regulation since the miRNAs belonging to one cluster tend to be involved in the same network module, which performs a relatively isolated biological function. However, the homo-clustered miRNAs show a direct regulatory coordination that is realized by one-step regulation (i.e. the direct regulation of the coordinated targets, whereas the hetero-clustered miRNAs show an indirect regulatory coordination that is realized by a regulation comprising at least three steps (e.g. the regulation on the coordinated targets by a miRNA through a sequential action of two TFs. The direct and indirect regulation target different categories of genes, the former predominantly regulating genes involved in emergent responses, the latter targeting genes that imply long-term effects. Conclusion The genomic clustering of miRNAs is closely related to the coordinated regulation in the gene regulatory network. The pattern of

  2. 叉头状转录因子O1对游离脂肪酸诱导的人肝癌细胞株HepG-2胰岛素抵抗和脂质堆积作用的研究%Effect of forkhead transcription factor O1 on free fatty acid induced insulin resistance and steatosis by sterol-regulatory element binding protein-1c pathway

    Institute of Scientific and Technical Information of China (English)

    张鹏宇; 秦贵军; 李雪峰; 任高飞; 刘会苗

    2012-01-01

    Objective To study the effects and potential mechanisms of Forkhead transcription factor O1 (FoxO1) on free fatty acid (FFA) induced insulin resistance (IR) and steatosis.Methods HepG-2 cells were induced to a status of insulin resistance by being exposed to 5.0 × 10 4 mmol/L palmitic acid (PA) for 24 hours.HepG-2 cells were devided into 4 groups,the HepG-2 cell group cultured with normal medium,the palmitic acid group,the blank plasmid group,and the siFoxO1 group.PA was added to normal medium to a final concentration of 5.0 × 10 -4 mol/L.The expression levels of FoxO1 in different groups were detected by RT-PCR.The glucose consumption was detected by using glucose oxidase method.MTT method was used to detect the proliferation of HepG-2 cells.Steatosis of HepG-2 cells was observed by Oil Red O staining.The mRNA and protein expression of SREBP-1c were determined by RT-PCR and Western blot.Results Compared with control,the glucose consumption of cells cultured with FFA was significantly reduced( 1.17 ±0.56 vs 4.31 ±0.21,t =10.587,P <0.01 ).Cellular lipid accumulation,the expressions of FoxO1 mRNA ( 0.78 ± 0.10 vs 0.51 ± 0.12,t =3.629,P < 0.05 ),SREBP-1c mRNA (0.71 ±0.17 vs 0.25 ±0.08,t =6.290,P <0.05),and the protein of SREBP-1c (0.69 ±0.10 vs 0.41 ± 0.07,t =4.797,P <0.01 )was increased.After transfected by siFoxO1 plasmids using Lipofectamine 2000,the mRNA expression of FoxO1 (0.38 ± 0.06 vs 0.78 ± 0.1 0,t =7.164,P < 0.01 ),SREB9-1 c (0.45 ±0.13 vs 0.71 ±0.17,t =2.479,P <0.05) and the SREBP-1 c protein expression (0.41 ±0.06 vs 0.69 ±0.10,t =4.797,P <0.01 ) were significantly decreased after tranfected by siFoxO1 plasminds,whereas the glucose consumption obviously the glucose consumption obviously increased ( 2.26 ± 0.41 vs 1.17 ± 0.56,t=3.144,P <0.05).The cellular lipod accumulation was decrease after transfected by siFoxO1.There was no remarkable difference between the palmitic acid group,and the blank plasmid group. Conclusions

  3. The effects of sterol structure upon sterol esterification.

    Science.gov (United States)

    Lin, Don S; Steiner, Robert D; Merkens, Louise S; Pappu, Anuradha S; Connor, William E

    2010-01-01

    Cholesterol is esterified in mammals by two enzymes: LCAT (lecithin cholesterol acyltransferase) in plasma and ACAT(1) and ACAT(2) (acyl-CoA cholesterol acyltransferases) in the tissues. We hypothesized that the sterol structure may have significant effects on the outcome of esterification by these enzymes. To test this hypothesis, we analyzed sterol esters in plasma and tissues in patients having non-cholesterol sterols (sitosterolemia and Smith-Lemli-Opitz syndrome). The esterification of a given sterol was defined as the sterol ester percentage of total sterols. The esterification of cholesterol in plasma by LCAT was 67% and in tissues by ACAT was 64%. Esterification of nine sterols (cholesterol, cholestanol, campesterol, stigmasterol, sitosterol, campestanol, sitostanol, 7-dehydrocholesterol and 8-dehydrocholesterol) was examined. The relative esterification (cholesterol being 1.0) of these sterols by the plasma LCAT was 1.00, 0.95, 0.89, 0.40, 0.85, 0.82 and 0.80, 0.69 and 0.82, respectively. The esterification by the tissue ACAT was 1.00, 1.29, 0.75, 0.49, 0.45, 1.21 and 0.74, respectively. The predominant fatty acid of the sterol esters was linoleic acid for LCAT and oleic acid for ACAT. We compared the esterification of two sterols differing by only one functional group (a chemical group attached to sterol nucleus) and were able to quantify the effects of individual functional groups on sterol esterification. The saturation of the A ring of cholesterol increased ester formation by ACAT by 29% and decreased the esterification by LCAT by 5.9%. Esterification by ACAT and LCAT was reduced, respectively, by 25 and 11% by the presence of an additional methyl group on the side chain of cholesterol at the C-24 position. This data supports our hypothesis that the structure of the sterol substrate has a significant effect on its esterification by ACAT or LCAT.

  4. Origin assessment of EV olive oils by esterified sterols analysis.

    Science.gov (United States)

    Giacalone, Rosa; Giuliano, Salvatore; Gulotta, Eleonora; Monfreda, Maria; Presti, Giovanni

    2015-12-01

    In this study extra virgin olive oils of Italian and non-Italian origin (from Spain, Tunisia and blends of EU origin) were differentiated by GC-FID analysis of sterols and esterified sterols followed by chemometric tools. PCA allowed to highlight the high significance of esterified sterols to characterise extra virgin olive oils in relation to their origin. SIMCA provided a sensitivity and specificity of 94.39% and 91.59% respectively; furthermore, an external set of 54 extra virgin olive oils bearing a designation of Italian origin on the labelling was tested by SIMCA. Prediction results were also compared with organoleptic assessment. Finally, the poor correlation found between ethylesters and esterified sterols allowed to hazard the guess, worthy of further investigations, that esterified sterols may prove to be promising in studies of geographical discrimination: indeed they appear to be independent of those factors causing the formation of ethyl esters and related to olive oil production.

  5. Putative regulatory factors associated with intramuscular fat content.

    Directory of Open Access Journals (Sweden)

    Aline S M Cesar

    Full Text Available Intramuscular fat (IMF content is related to insulin resistance, which is an important prediction factor for disorders, such as cardiovascular disease, obesity and type 2 diabetes in human. At the same time, it is an economically important trait, which influences the sensorial and nutritional value of meat. The deposition of IMF is influenced by many factors such as sex, age, nutrition, and genetics. In this study Nellore steers (Bos taurus indicus subspecies were used to better understand the molecular mechanisms involved in IMF content. This was accomplished by identifying differentially expressed genes (DEG, biological pathways and putative regulatory factors. Animals included in this study had extreme genomic estimated breeding value (GEBV for IMF. RNA-seq analysis, gene set enrichment analysis (GSEA and co-expression network methods, such as partial correlation coefficient with information theory (PCIT, regulatory impact factor (RIF and phenotypic impact factor (PIF were utilized to better understand intramuscular adipogenesis. A total of 16,101 genes were analyzed in both groups (high (H and low (L GEBV and 77 DEG (FDR 10% were identified between the two groups. Pathway Studio software identified 13 significantly over-represented pathways, functional classes and small molecule signaling pathways within the DEG list. PCIT analyses identified genes with a difference in the number of gene-gene correlations between H and L group and detected putative regulatory factors involved in IMF content. Candidate genes identified by PCIT include: ANKRD26, HOXC5 and PPAPDC2. RIF and PIF analyses identified several candidate genes: GLI2 and IGF2 (RIF1, MPC1 and UBL5 (RIF2 and a host of small RNAs, including miR-1281 (PIF. These findings contribute to a better understanding of the molecular mechanisms that underlie fat content and energy balance in muscle and provide important information for the production of healthier beef for human consumption.

  6. "Dinoflagellate Sterols" in marine diatoms.

    Science.gov (United States)

    Giner, José-Luis; Wikfors, Gary H

    2011-10-01

    Sterol compositions for three diatom species, recently shown to contain sterols with side chains typically found in dinoflagellates, were determined by HPLC and ¹H NMR spectroscopic analyses. The centric diatom Triceratium dubium (=Biddulphia sp., CCMP 147) contained the highest percentage of 23-methylated sterols (37.2% (24R)-23-methylergosta-5,22-dienol), whereas the pennate diatom Delphineis sp. (CCMP 1095) contained the cyclopropyl sterol gorgosterol, as well as the 27-norsterol occelasterol. The sterol composition of Ditylum brightwellii (CCMP 358) was the most complex, containing Δ⁰- and Δ⁷-sterols, in addition to the predominant Δ⁵-sterols. A pair of previously unknown sterols, stigmasta-5,24,28-trienol and stigmasta-24,28-dienol, were detected in D. brightwellii and their structures were determined by NMR spectroscopic analysis and by synthesis of the former sterol from saringosterol. Also detected in D. brightwellii was the previously unknown 23-methylcholesta-7,22-dienol. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Nuclear hormone receptors put immunity on sterols.

    Science.gov (United States)

    Santori, Fabio R

    2015-10-01

    Nuclear hormone receptors (NHRs) are transcription factors regulated by small molecules. The functions of NHRs range from development of primary and secondary lymphoid organs, to regulation of differentiation and function of DCs, macrophages and T cells. The human genome has 48 classic (hormone and vitamin receptors) and nonclassic (all others) NHRs; 17 nonclassic receptors are orphans, meaning that the endogenous ligand is unknown. Understanding the function of orphan NHRs requires the identification of their natural ligands. The mevalonate pathway, including its sterol and nonsterol intermediates and derivatives, is a source of ligands for many classic and nonclassic NHRs. For example, cholesterol biosynthetic intermediates (CBIs) are natural ligands for RORγ/γt. CBIs are universal endogenous metabolites in mammalian cells, and to study NHRs that bind CBIs requires ligand-free reporters system in sterol auxotroph cells. Furthermore, RORγ/γt shows broad specificity to sterol lipids, suggesting that RORγ/γt is either a general sterol sensor or specificity is defined by an abundant endogenous ligand. Unlike other NHRs, which regulate specific metabolic pathways, there is no connection between the genetic programs induced by RORγ/γt and ligand biosynthesis. In this review, we summarize the roles of nonclassic NHRs and their potential ligands in the immune system.

  8. Phylogenetic distribution of fungal sterols.

    Directory of Open Access Journals (Sweden)

    John D Weete

    Full Text Available BACKGROUND: Ergosterol has been considered the "fungal sterol" for almost 125 years; however, additional sterol data superimposed on a recent molecular phylogeny of kingdom Fungi reveals a different and more complex situation. METHODOLOGY/PRINCIPAL FINDINGS: The interpretation of sterol distribution data in a modern phylogenetic context indicates that there is a clear trend from cholesterol and other Delta(5 sterols in the earliest diverging fungal species to ergosterol in later diverging fungi. There are, however, deviations from this pattern in certain clades. Sterols of the diverse zoosporic and zygosporic forms exhibit structural diversity with cholesterol and 24-ethyl -Delta(5 sterols in zoosporic taxa, and 24-methyl sterols in zygosporic fungi. For example, each of the three monophyletic lineages of zygosporic fungi has distinctive major sterols, ergosterol in Mucorales, 22-dihydroergosterol in Dimargaritales, Harpellales, and Kickxellales (DHK clade, and 24-methyl cholesterol in Entomophthorales. Other departures from ergosterol as the dominant sterol include: 24-ethyl cholesterol in Glomeromycota, 24-ethyl cholest-7-enol and 24-ethyl-cholesta-7,24(28-dienol in rust fungi, brassicasterol in Taphrinales and hypogeous pezizalean species, and cholesterol in Pneumocystis. CONCLUSIONS/SIGNIFICANCE: Five dominant end products of sterol biosynthesis (cholesterol, ergosterol, 24-methyl cholesterol, 24-ethyl cholesterol, brassicasterol, and intermediates in the formation of 24-ethyl cholesterol, are major sterols in 175 species of Fungi. Although most fungi in the most speciose clades have ergosterol as a major sterol, sterols are more varied than currently understood, and their distribution supports certain clades of Fungi in current fungal phylogenies. In addition to the intellectual importance of understanding evolution of sterol synthesis in fungi, there is practical importance because certain antifungal drugs (e.g., azoles target reactions in

  9. DNA residence time is a regulatory factor of transcription repression.

    Science.gov (United States)

    Clauß, Karen; Popp, Achim P; Schulze, Lena; Hettich, Johannes; Reisser, Matthias; Escoter Torres, Laura; Uhlenhaut, N Henriette; Gebhardt, J Christof M

    2017-08-21

    Transcription comprises a highly regulated sequence of intrinsically stochastic processes, resulting in bursts of transcription intermitted by quiescence. In transcription activation or repression, a transcription factor binds dynamically to DNA, with a residence time unique to each factor. Whether the DNA residence time is important in the transcription process is unclear. Here, we designed a series of transcription repressors differing in their DNA residence time by utilizing the modular DNA binding domain of transcription activator-like effectors (TALEs) and varying the number of nucleotide-recognizing repeat domains. We characterized the DNA residence times of our repressors in living cells using single molecule tracking. The residence times depended non-linearly on the number of repeat domains and differed by more than a factor of six. The factors provoked a residence time-dependent decrease in transcript level of the glucocorticoid receptor-activated gene SGK1. Down regulation of transcription was due to a lower burst frequency in the presence of long binding repressors and is in accordance with a model of competitive inhibition of endogenous activator binding. Our single molecule experiments reveal transcription factor DNA residence time as a regulatory factor controlling transcription repression and establish TALE-DNA binding domains as tools for the temporal dissection of transcription regulation. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Uncovering Transcriptional Regulatory Networks by Sparse Bayesian Factor Model

    Science.gov (United States)

    Meng, Jia; Zhang, Jianqiu(Michelle); Qi, Yuan(Alan); Chen, Yidong; Huang, Yufei

    2010-12-01

    The problem of uncovering transcriptional regulation by transcription factors (TFs) based on microarray data is considered. A novel Bayesian sparse correlated rectified factor model (BSCRFM) is proposed that models the unknown TF protein level activity, the correlated regulations between TFs, and the sparse nature of TF-regulated genes. The model admits prior knowledge from existing database regarding TF-regulated target genes based on a sparse prior and through a developed Gibbs sampling algorithm, a context-specific transcriptional regulatory network specific to the experimental condition of the microarray data can be obtained. The proposed model and the Gibbs sampling algorithm were evaluated on the simulated systems, and results demonstrated the validity and effectiveness of the proposed approach. The proposed model was then applied to the breast cancer microarray data of patients with Estrogen Receptor positive ([InlineEquation not available: see fulltext.]) status and Estrogen Receptor negative ([InlineEquation not available: see fulltext.]) status, respectively.

  11. Uncovering Transcriptional Regulatory Networks by Sparse Bayesian Factor Model

    Directory of Open Access Journals (Sweden)

    Qi Yuan(Alan

    2010-01-01

    Full Text Available Abstract The problem of uncovering transcriptional regulation by transcription factors (TFs based on microarray data is considered. A novel Bayesian sparse correlated rectified factor model (BSCRFM is proposed that models the unknown TF protein level activity, the correlated regulations between TFs, and the sparse nature of TF-regulated genes. The model admits prior knowledge from existing database regarding TF-regulated target genes based on a sparse prior and through a developed Gibbs sampling algorithm, a context-specific transcriptional regulatory network specific to the experimental condition of the microarray data can be obtained. The proposed model and the Gibbs sampling algorithm were evaluated on the simulated systems, and results demonstrated the validity and effectiveness of the proposed approach. The proposed model was then applied to the breast cancer microarray data of patients with Estrogen Receptor positive ( status and Estrogen Receptor negative ( status, respectively.

  12. Survival strategies of a sterol auxotroph

    Science.gov (United States)

    Carvalho, Maria; Schwudke, Dominik; Sampaio, Julio L.; Palm, Wilhelm; Riezman, Isabelle; Dey, Gautam; Gupta, Gagan D.; Mayor, Satyajit; Riezman, Howard; Shevchenko, Andrej; Kurzchalia, Teymuras V.; Eaton, Suzanne

    2010-01-01

    The high sterol concentration in eukaryotic cell membranes is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila cannot synthesize sterols, but do require them for development. Does this simply reflect a requirement for sterols in steroid hormone biosynthesis, or is bulk membrane sterol also essential in Drosophila? If the latter is true, how do they survive fluctuations in sterol availability and maintain membrane homeostasis? Here, we show that Drosophila require both bulk membrane sterol and steroid hormones in order to complete adult development. When sterol availability is restricted, Drosophila larvae modulate their growth to maintain membrane sterol levels within tight limits. When dietary sterol drops below a minimal threshold, larvae arrest growth and development in a reversible manner. Strikingly, membrane sterol levels in arrested larvae are dramatically reduced (dropping sixfold on average) in most tissues except the nervous system. Thus, sterols are dispensable for maintaining the basic membrane biophysical properties required for cell viability; these functions can be performed by non-sterol lipids when sterols are unavailable. However, bulk membrane sterol is likely to have essential functions in specific tissues during development. In tissues in which sterol levels drop, the overall level of sphingolipids increases and the proportion of different sphingolipid variants is altered. These changes allow survival, but not growth, when membrane sterol levels are low. This relationship between sterols and sphingolipids could be an ancient and conserved principle of membrane homeostasis. PMID:20940226

  13. Phylogenetic Distribution of Fungal Sterols

    Science.gov (United States)

    Weete, John D.; Abril, Maritza; Blackwell, Meredith

    2010-01-01

    Background Ergosterol has been considered the “fungal sterol” for almost 125 years; however, additional sterol data superimposed on a recent molecular phylogeny of kingdom Fungi reveals a different and more complex situation. Methodology/Principal Findings The interpretation of sterol distribution data in a modern phylogenetic context indicates that there is a clear trend from cholesterol and other Δ5 sterols in the earliest diverging fungal species to ergosterol in later diverging fungi. There are, however, deviations from this pattern in certain clades. Sterols of the diverse zoosporic and zygosporic forms exhibit structural diversity with cholesterol and 24-ethyl -Δ5 sterols in zoosporic taxa, and 24-methyl sterols in zygosporic fungi. For example, each of the three monophyletic lineages of zygosporic fungi has distinctive major sterols, ergosterol in Mucorales, 22-dihydroergosterol in Dimargaritales, Harpellales, and Kickxellales (DHK clade), and 24-methyl cholesterol in Entomophthorales. Other departures from ergosterol as the dominant sterol include: 24-ethyl cholesterol in Glomeromycota, 24-ethyl cholest-7-enol and 24-ethyl-cholesta-7,24(28)-dienol in rust fungi, brassicasterol in Taphrinales and hypogeous pezizalean species, and cholesterol in Pneumocystis. Conclusions/Significance Five dominant end products of sterol biosynthesis (cholesterol, ergosterol, 24-methyl cholesterol, 24-ethyl cholesterol, brassicasterol), and intermediates in the formation of 24-ethyl cholesterol, are major sterols in 175 species of Fungi. Although most fungi in the most speciose clades have ergosterol as a major sterol, sterols are more varied than currently understood, and their distribution supports certain clades of Fungi in current fungal phylogenies. In addition to the intellectual importance of understanding evolution of sterol synthesis in fungi, there is practical importance because certain antifungal drugs (e.g., azoles) target reactions in the synthesis of

  14. Bayesian non-negative factor analysis for reconstructing transcription factor mediated regulatory networks

    Directory of Open Access Journals (Sweden)

    Chen Yidong

    2011-10-01

    Full Text Available Abstract Background Transcriptional regulation by transcription factor (TF controls the time and abundance of mRNA transcription. Due to the limitation of current proteomics technologies, large scale measurements of protein level activities of TFs is usually infeasible, making computational reconstruction of transcriptional regulatory network a difficult task. Results We proposed here a novel Bayesian non-negative factor model for TF mediated regulatory networks. Particularly, the non-negative TF activities and sample clustering effect are modeled as the factors from a Dirichlet process mixture of rectified Gaussian distributions, and the sparse regulatory coefficients are modeled as the loadings from a sparse distribution that constrains its sparsity using knowledge from database; meantime, a Gibbs sampling solution was developed to infer the underlying network structure and the unknown TF activities simultaneously. The developed approach has been applied to simulated system and breast cancer gene expression data. Result shows that, the proposed method was able to systematically uncover TF mediated transcriptional regulatory network structure, the regulatory coefficients, the TF protein level activities and the sample clustering effect. The regulation target prediction result is highly coordinated with the prior knowledge, and sample clustering result shows superior performance over previous molecular based clustering method. Conclusions The results demonstrated the validity and effectiveness of the proposed approach in reconstructing transcriptional networks mediated by TFs through simulated systems and real data.

  15. Clinical trials in "emerging markets": regulatory considerations and other factors.

    Science.gov (United States)

    Singh, Romi; Wang, Ouhong

    2013-11-01

    Clinical studies are being placed in emerging markets as part of global drug development programs to access large pool of eligible patients and to benefit from a cost effective structure. However, over the last few years, the definition of "emerging markets" is being revisited, especially from a regulatory perspective. For purposes of this article, countries outside US, EU and the traditional "western countries" are discussed. Multiple factors are considered for placement of clinical studies such as adherence to Good Clinical Practice (GCP), medical infrastructure & standard of care, number of eligible patients, etc. This article also discusses other quantitative factors such as country's GDP, patent applications, healthcare expenditure, healthcare infrastructure, corruption, innovation, etc. These different factors and indexes are correlated to the number of clinical studies ongoing in the "emerging markets". R&D, healthcare expenditure, technology infrastructure, transparency, and level of innovation, show a significant correlation with the number of clinical trials being conducted in these countries. This is the first analysis of its kind to evaluate and correlate the various other factors to the number of clinical studies in a country.

  16. Study of Behavior of Sterols at Interfaces

    Science.gov (United States)

    Klein, P. D.; Knight, J. C.; Szczepanik, P. A.

    1968-01-01

    Behavior of sterols and sterol acetates on various types of interfaces indicates that the function of a sterol depends upon a surface orientation and surface energy of the interface. Column-chromatographic techniques determine the retention volume of various sterols under standard conditions.

  17. Cell cycle regulatory factors in juxta-tumoral renal parenchyma.

    Science.gov (United States)

    Petruşcă, Daniela Nicoleta; Petrescu, Amelia; Vrabie, Camelia; Niculescu, L; Jinga, V; Diaconu, Carmen; Braşoveanu, Lorelei

    2005-01-01

    The aim of this study was to evaluate regulatory cell cycle factors in juxta-tumoral renal parenchyma in order to obtain information regarding early primary changes occurred in normal renal cells. Specimens of juxta-tumoral renal parenchyma were harvested from the tumoral kidney in 10 patients with no history of treatment before surgery. The expression of p53, Bcl-2, Rb and PCNA was studied by immunohistochemical methods in paraffin-embedded tissues. The apoptotic status was evaluated by flow-cytometry analysis following propidium iodide incorporation. The p53 protein expression was recognized in most of the cases (80%) with different intensities. High intensity apoptotic process detected in juxta-tumoral parenchyma seemed to be p53 dependent and well correlated with the low Bcl-2 expression. 70% of cases were Rb positive. In this type of tissue Rb has only an anti-proliferative and anti-tumoral role. PCNA was present in half of the cases being low expressed due to the tissue regenerating mechanism. Our data suggest that the high intensity of programmed cell death in this type of tissue is supported by the status of cell regulatory factors that control this process. Previous studies have demonstrated that healthy renal tissue has neither apoptosis nor mitotic activity. Juxta-tumoral renal tissue is also displaying normal morphology and DNA content (diploidy) but the microenvironmental status induced by the tumor presence prompts cells to choose death rather than malignant transformation. Further studies are necessary to emphasize if these results have a clinical relevance for the outcome of therapeutical approaches in renal carcinomas.

  18. MicroRNA and transcription factor mediated regulatory network analysis reveals critical regulators and regulatory modules in myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Guangde Zhang

    Full Text Available Myocardial infarction (MI is a severe coronary artery disease and a leading cause of mortality and morbidity worldwide. However, the molecular mechanisms of MI have yet to be fully elucidated. In this study, we compiled MI-related genes, MI-related microRNAs (miRNAs and known human transcription factors (TFs, and we then identified 1,232 feed-forward loops (FFLs among these miRNAs, TFs and their co-regulated target genes through integrating target prediction. By merging these FFLs, the first miRNA and TF mediated regulatory network for MI was constructed, from which four regulators (SP1, ESR1, miR-21-5p and miR-155-5p and three regulatory modules that might play crucial roles in MI were then identified. Furthermore, based on the miRNA and TF mediated regulatory network and literature survey, we proposed a pathway model for miR-21-5p, the miR-29 family and SP1 to demonstrate their potential co-regulatory mechanisms in cardiac fibrosis, apoptosis and angiogenesis. The majority of the regulatory relations in the model were confirmed by previous studies, which demonstrated the reliability and validity of this miRNA and TF mediated regulatory network. Our study will aid in deciphering the complex regulatory mechanisms involved in MI and provide putative therapeutic targets for MI.

  19. Altered oncomodules underlie chromatin regulatory factors driver mutations.

    Science.gov (United States)

    Frigola, Joan; Iturbide, Ane; Lopez-Bigas, Nuria; Peiro, Sandra; Gonzalez-Perez, Abel

    2016-05-24

    Chromatin regulatory factors (CRFs), are known to be involved in tumorigenesis in several cancer types. Nevertheless, the molecular mechanisms through which driver alterations of CRFs cause tumorigenesis remain unknown. Here, we developed a CRFs Oncomodules Discovery approach, which mines several sources of cancer genomics and perturbaomics data. The approach prioritizes sets of genes significantly miss-regulated in primary tumors (oncomodules) bearing mutations of driver CRFs. We applied the approach to eleven TCGA tumor cohorts and uncovered oncomodules potentially associated to mutations of five driver CRFs in three cancer types. Our results revealed, for example, the potential involvement of the mTOR pathway in the development of tumors with loss-of-function mutations of MLL2 in head and neck squamous cell carcinomas. The experimental validation that MLL2 loss-of-function increases the sensitivity of cancer cell lines to mTOR inhibition lends further support to the validity of our approach. The potential oncogenic modules detected by our approach may guide experiments proposing ways to indirectly target driver mutations of CRFs.

  20. Arenavirus nucleoprotein targets interferon regulatory factor-activating kinase IKKε.

    Science.gov (United States)

    Pythoud, Christelle; Rodrigo, W W Shanaka I; Pasqual, Giulia; Rothenberger, Sylvia; Martínez-Sobrido, Luis; de la Torre, Juan Carlos; Kunz, Stefan

    2012-08-01

    Arenaviruses perturb innate antiviral defense by blocking induction of type I interferon (IFN) production. Accordingly, the arenavirus nucleoprotein (NP) was shown to block activation and nuclear translocation of interferon regulatory factor 3 (IRF3) in response to virus infection. Here, we sought to identify cellular factors involved in innate antiviral signaling targeted by arenavirus NP. Consistent with previous studies, infection with the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) prevented phosphorylation of IRF3 in response to infection with Sendai virus, a strong inducer of the retinoic acid-inducible gene I (RIG-I)/mitochondrial antiviral signaling (MAVS) pathway of innate antiviral signaling. Using a combination of coimmunoprecipitation and confocal microscopy, we found that LCMV NP associates with the IκB kinase (IKK)-related kinase IKKε but that, rather unexpectedly, LCMV NP did not bind to the closely related TANK-binding kinase 1 (TBK-1). The NP-IKKε interaction was highly conserved among arenaviruses from different clades. In LCMV-infected cells, IKKε colocalized with NP but not with MAVS located on the outer membrane of mitochondria. LCMV NP bound the kinase domain (KD) of IKKε (IKBKE) and blocked its autocatalytic activity and its ability to phosphorylate IRF3, without undergoing phosphorylation. Together, our data identify IKKε as a novel target of arenavirus NP. Engagement of NP seems to sequester IKKε in an inactive complex. Considering the important functions of IKKε in innate antiviral immunity and other cellular processes, the NP-IKKε interaction likely plays a crucial role in arenavirus-host interaction.

  1. Sterols of the fungi - Distribution and biosynthesis

    Science.gov (United States)

    Weete, J. D.

    1973-01-01

    The importance of sterols in the growth and reproduction in fungi is becoming increasingly apparent. This article concerns the composition and biosynthesis of ergosterol in these organisms. Comparison to plant and animal sterol formation are made.

  2. Distribution and functions of sterols and sphingolipids.

    Science.gov (United States)

    Hannich, J Thomas; Umebayashi, Kyohei; Riezman, Howard

    2011-05-01

    Sterols and sphingolipids are considered mainly eukaryotic lipids even though both are present in some prokaryotes, with sphingolipids being more widespread than sterols. Both sterols and sphingolipids differ in their structural features in vertebrates, plants, and fungi. Interestingly, some invertebrates cannot synthesize sterols de novo and seem to have a reduced dependence on sterols. Sphingolipids and sterols are found in the plasma membrane, but we do not have a clear picture of their precise intracellular localization. Advances in lipidomics and subcellular fractionation should help to improve this situation. Genetic approaches have provided insights into the diversity of sterol and sphingolipid functions in eukaryotes providing evidence that these two lipid classes function together. Intermediates in sphingolipid biosynthesis and degradation are involved in signaling pathways, whereas sterol structures are converted to hormones. Both lipids have been implicated in regulating membrane trafficking.

  3. Sterols of the fungi - Distribution and biosynthesis

    Science.gov (United States)

    Weete, J. D.

    1973-01-01

    The importance of sterols in the growth and reproduction in fungi is becoming increasingly apparent. This article concerns the composition and biosynthesis of ergosterol in these organisms. Comparison to plant and animal sterol formation are made.

  4. Bim nuclear translocation and inactivation by viral interferon regulatory factor.

    Directory of Open Access Journals (Sweden)

    Young Bong Choi

    Full Text Available Viral replication efficiency is in large part governed by the ability of viruses to counteract pro-apoptotic signals induced by infection of the host cell. Human herpesvirus 8 (HHV-8 uses several strategies to block the host's innate antiviral defenses via interference with interferon and apoptotic signaling. Contributors include the four viral interferon regulatory factors (vIRFs 1-4, which function in dominant negative fashion to block cellular IRF activities in addition to targeting IRF signaling-induced proteins such as p53 and inhibiting other inducers of apoptosis such as TGFbeta receptor-activated Smad transcription factors. Here we identify direct targeting by vIRF-1 of BH3-only pro-apoptotic Bcl-2 family member Bim, a key negative regulator of HHV-8 replication, to effect its inactivation via nuclear translocation. vIRF-1-mediated relocalization of Bim was identified in transfected cells, by both immunofluorescence assay and western analysis of fractionated cell extracts. Also, co-localization of vIRF-1 and Bim was detected in nuclei of lytically infected endothelial cells. In vitro co-precipitation assays using purified vIRF-1 and Bim revealed direct interaction between the proteins, and Bim-binding residues of vIRF-1 were mapped by deletion and point mutagenesis. Generation and experimental utilization of Bim-refractory vIRF-1 variants revealed the importance of vIRF-1:Bim interaction, specifically, in pro-replication and anti-apoptotic activity of vIRF-1. Furthermore, blocking of the interaction with cell-permeable peptide corresponding to the Bim-binding region of vIRF-1 confirmed the relevance of vIRF-1:Bim association to vIRF-1 pro-replication activity. To our knowledge, this is the first report of an IRF protein that interacts with a Bcl-2 family member and of nuclear sequestration of Bim or any other member of the family as a means of inactivation. The data presented reveal a novel mechanism utilized by a virus to control

  5. Universal Behavior of Membranes with Sterols

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Rowat, Amy C.; Brief, E.

    2006-01-01

    Lanosterol is the biosynthetic precursor of cholesterol and ergosterol, sterols that predominate in the membranes of mammals and lower eukaryotes, respectively. These three sterols are structurally quite similar, yet their relative effects on membranes have been shown to differ. Here we study...... to different degrees by these structurally distinct sterols, yet nonetheless exhibit universal behavior....

  6. Plant Sterol Diversity in Pollen from Angiosperms.

    Science.gov (United States)

    Villette, Claire; Berna, Anne; Compagnon, Vincent; Schaller, Hubert

    2015-08-01

    Here we have examined the composition of free sterols and steryl esters of pollen from selected angiosperm species, as a first step towards a comprehensive analysis of sterol biogenesis in the male gametophyte. We detected four major sterol structural groups: cycloartenol derivatives bearing a 9β,19-cyclopropyl group, sterols with a double bond at C-7(8), sterols with a double bond at C-5(6), and stanols. All these groups were unequally distributed among species. However, the distribution of sterols as free sterols or as steryl esters in pollen grains indicated that free sterols were mostly Δ(5)-sterols and that steryl esters were predominantly 9β,19-cyclopropyl sterols. In order to link the sterol composition of a pollen grain at anthesis with the requirement for membrane lipid constituents of the pollen tube, we germinated pollen grains from Nicotiana tabacum, a model plant in reproductive biology. In the presence of radiolabelled mevalonic acid and in a time course series of measurements, we showed that cycloeucalenol was identified as the major neosynthesized sterol. Furthermore, the inhibition of cycloeucalenol neosynthesis by squalestatin was in full agreement with a de novo biogenesis and an apparent truncated pathway in the pollen tube.

  7. Bioactivities of six sterols isolated from marine invertebrates.

    Science.gov (United States)

    Zhou, Xuefeng; Sun, Jianfan; Ma, Wanlei; Fang, Wei; Chen, Zhefan; Yang, Bin; Liu, Yonghong

    2014-02-01

    Epidioxy sterols and sterols with special side chains, such as hydroperoxyl sterols, usually obtained from marine natural products, are attractive for bioactivities. To isolate and screen bioactive and special sterols from China Sea invertebrates. Two hydroperoxyl sterols (1 and 2) from the sponge Xestospongia testudinaria Lamarck (Petrosiidae), three epidioxy sterols (3-5) from the sea urchin Glyptocidaris crenularis A. Agassiz (Glyptocidaridae), sponge Mycale sp. (Mycalidae) and gorgonian Dichotella gemmacea Milne Edwards and Haime (Ellisellidae) and an unusual sterol with 25-acetoxy-19-oate (6) also from D. gemmacea were obtained and identified. Using high-throughput screening, their bioactivities were tested toward Forkhead box O 3a (Foxo3a), 3-hydroxy-3-methylglutaryl CoA reductase gene fluorescent protein (HMGCR-GFP), nuclear factor kappa B (NF-κB) luciferase, peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α), protein-tyrosine phosphatase 1B (PTP1B), mitochondrial membrane permeabilization (MMP) and adenosine monophosphate-activated protein kinase. Their structures were determined by comparing their nuclear magnetic resonance data with those reported in the literature. Three epidioxy sterols (3-5) showed inhibitory activities toward Foxo3a, HMGCR-GFP and NF-κB-luciferase with the IC50 values 4.9-6.8 μg/mL. The hydroperoxyl sterol 29-hydroperoxystigmasta-5,24(28)-dien-3-ol (2) had diverse inhibitory activities against Foxo3a, HMGCR-GFP, NF-κB-luciferase, PGC-1α, PTP1B and MMP, with IC50 values of 3.8-19.1 μg/mL. The bioactivities of 3-5 showed that 5α,8α-epidioxy is the active group. Otherwise, the most plausible biosynthesis pathway for 1 and 2 in sponge involves the abstraction of an allylic proton by an activated oxygen, such as O2, along with migration of carbon-carbon double bond. Therefore, the bioactive and unstable steroid should be biosynthesized in sponge under a special ecological environment to act as a defensive

  8. Characteristics of sterol uptake in Saccharomyces cerevisiae.

    OpenAIRE

    Lorenz, R T; Rodriguez, R J; Lewis, T A; Parks, L W

    1986-01-01

    A Saccharomyces cerevisiae sterol auxotroph, FY3 (alpha hem1 erg7 ura), was used to probe the characteristics of sterol uptake in S. cerevisiae. The steady-state cellular concentration of free sterol at the late exponential phase of growth could be adjusted within a 10-fold range by varying the concentration of exogenously supplied sterol. When cultured on 1 microgram of sterol ml-1, the cells contained a minimal cellular free-cholesterol concentration of 0.85 nmol/mg (dry weight) and were te...

  9. 腺病毒介导的秦川牛固醇调节元件结合蛋白2基因(SREBP2)过表达载体的构建与鉴定%Construction and Identification of Recombinant Adenovirus Vector Specific to Qinchuan Cattle(Bos taurus) Derived Sterol Regulatory Element Binding Protein 2 Gene (SREBP2)

    Institute of Scientific and Technical Information of China (English)

    付常振; 刘扬; 昝林森; 王虹; 成功; 王嘉力

    2013-01-01

    Sterol regulatory element binding protein 2(SERBP2) is a basic-helix-loop-helix-luecine zipper factor which regulates the metabolization process of cholesterol.We cloned the SREBP2 gene from Qinchuan cattle (Bos taurus) and constructed the overexpression adenoviral vector,and packed and amplified the virus for a high titer,as a antecedent work for the further study of cellular level function of SERBP2 gene.Total RNA was extracted from the adipose tissue of Qinchuan cattle and then reversely transcripted to cDNA.A pair of exclusive primers were designed according to the GenBank sequence information of SREBP2 gene(Accession No.NM_001205600) to amplify the complete coding sequence(CDS) area of SREBP2 gene by polymerase chain reaction (PCR).The fragments containing CDS area of SREBP2 gene were inserted into the shuttle vector to construct the pAdTrack-CMV-SREBP2 plasmid.The recombinant plasmid and the blank control pAdTrack-CMV were linearized by digesting with restriction endonuclease Pine Ⅰ and subsequently transformed into Escherichia coli B J5183 containing pAdEasy-1 to homologous recombine and obtain the recombinant adenovirus plasmid pAd-SREBP2 and pAd-CMV.And then,the confirmed recombinant adenovirus plasmid pAd-SREBP2 was digested with Pac Ⅰ and transfected into 293A cell line to package and amplify the recombinant adenovirus Ad-SREBP2 and Ad-CMV,and to collect virus of high titer.The viral titer of AdSREBP2 and Ad-CMV was 7 × 108 and 1.3 × 109 GFU/mL respectively,measured by green fluorescent protein (GFP) labelled method.Qinchuan cattle derived preadipocyte was infected by Ad-SREBP2 and Ad-CMV to verify the availability of the virues.The expression of SREBP2 increased by 102.3 times after infected with the recombinant adenovirus for 48 h,determined by quantitative Real-time PCR.The cloning of SERBP2 gene of Qinchuan cattle obtaining of recombinant adenoviru and virus of high titer are set as foundation for the studies of the gene function on cellular

  10. DMPD: TLR pathways and IFN-regulatory factors: to each its own. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17273997 TLR pathways and IFN-regulatory factors: to each its own. Colonna M. Eur J... Immunol. 2007 Feb;37(2):306-9. (.png) (.svg) (.html) (.csml) Show TLR pathways and IFN-regulatory factors: ...to each its own. PubmedID 17273997 Title TLR pathways and IFN-regulatory factors: to each its own. Authors C

  11. DMPD: The role of the interferon regulatory factor (IRF) family in dendritic celldevelopment and function. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17702640 The role of the interferon regulatory factor (IRF) family in dendritic cel...b 2007 Aug 16. (.png) (.svg) (.html) (.csml) Show The role of the interferon regulatory factor (IRF) family ...e interferon regulatory factor (IRF) family in dendritic celldevelopment and function. Authors Gabriele L, O

  12. DMPD: The interferon regulatory factor family in host defense: mechanism of action. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17502370 The interferon regulatory factor family in host defense: mechanism of acti....html) (.csml) Show The interferon regulatory factor family in host defense: mechanism of action. PubmedID 1...7502370 Title The interferon regulatory factor family in host defense: mechanism

  13. Polymorphisms in SREBF1 and SREBF2, two antipsychotic-activated transcription factors controlling cellular lipogenesis, are associated with schizophrenia in German and Scandinavian samples

    DEFF Research Database (Denmark)

    Le Hellard, S; Mühleisen, T W; Djurovic, S

    2010-01-01

    Several studies have reported structural brain abnormalities, decreased myelination and oligodendrocyte dysfunction in schizophrenia. In the central nervous system, glia-derived de novo synthesized cholesterol is essential for both myelination and synaptogenesis. Previously, we demonstrated...... in glial cell lines that antipsychotic drugs induce the expression of genes involved in cholesterol and fatty acids biosynthesis through activation of the sterol regulatory element binding protein (SREBP) transcription factors, encoded by the sterol regulatory element binding transcription factor 1 (SREBF1......) and sterol regulatory element binding transcription factor 2 (SREBF2) genes. Considering the importance of these factors in the lipid biosynthesis and their possible involvement in antipsychotic drug effects, we hypothesized that genetic variants of SREBF1 and/or SREBF2 could affect schizophrenia...

  14. The Experiment Study of Kaiyuqingre's Prescription on the Expression of Sterol Regulatory Element Binding Protein-1c and Fatty Acid Synthase in Peritoneal Adipose Tissue of Spontaneous Type 2 Diabetes Mellitus Rats(OLETF rats)%开郁清热方干预自发2型糖尿病大鼠腹腔脂肪组织SREBP-1c、FAS表达的实验研究

    Institute of Scientific and Technical Information of China (English)

    朴春丽; 仝小林; 韩笑

    2011-01-01

    目的:研究开郁清热方对自发2型糖尿病大鼠(OLETF大鼠)腹腔脂肪组织SIREBP-1c、FAS蛋白及mRNA表达的影响.方法:将成模OLETF大鼠随机分为模型组、二甲双胍组、开郁清热方组,以LETO大鼠为空白对照组.采用免第疫组化、RT-PCR法检测腹腔脂肪组织SREBP-1c、FAS蛋白及mRNA的表达.结果:开郁清热方组的脂肪组织SBEBP-1c、FAS蛋白及mPNA表达水平较模型组明显减低(P<0.01,P<0.05).结论:开郁清热方具有降低自发2型糖尿病大鼠脂肪组织SREBP-lc、FAS蛋白及mRNA表达的作用.%Objective: To observe the effect of Kaiyuqingre's Prescription on the protein and mRNA expression of sterol regulatory element binding protein - 1c and fatty acid synthase in peritoneal adipose tissue of spontaneous Type 2 Diabetes Mellitus rats(OLEFF rats). Methods :A control study was carried out between the OLETF rats and LETO rats,and all OLETF rats were divided into three groups randomly:Model group,Metformin group and Kaiyuqingre′s Prescription group. Immunohistochemical method and real-time flourescent quantitative polymerase chain reaction(PCR)technology were used to detect the expression of sterol regulatory element binding protein - 1c and fatty acid synthaso in adipose tissue from the protein and gene levels in each group. Results: The sterol regulatory dement binding protein - 1c and fatty acid synthase protein and mRNA expression in rats 'adipose tissue:Contrast to Modal group,the Kaiyuqingre′s Prescription group is significantly lower. Conclusion :Kaiyuqingre's Prescription has a role of reducing the expression of protein and mRNA of sterol regulatory dement binding protein - 1c and fatty acid synthase in adipose tissue of spontaneous Type 2 Diabetes Mellitus rats.

  15. Targeted inactivation of Snail family EMT regulatory factors by a Co(III)-Ebox conjugate

    National Research Council Canada - National Science Library

    Harney, Allison S; Meade, Thomas J; LaBonne, Carole

    2012-01-01

    Snail family proteins are core EMT (epithelial-mesenchymal transition) regulatory factors that play essential roles in both development and disease processes and have been associated with metastasis in carcinomas...

  16. The sterols isolated from Evening Primrose oil modulate the release of proinflammatory mediators.

    Science.gov (United States)

    Montserrat-de la Paz, Sergio; Fernández-Arche, Angeles; Angel-Martín, María; García-Giménez, María Dolores

    2012-09-15

    Evening Primrose oil is a natural product extracted by cold-pressed from Oenothera biennis L. seeds. The unsaponifiable matter of this oil is an important source of interesting minor compounds, like long-chain fatty alcohols, sterols and tocopherols. In the present study, sterols were isolated from the unsaponifiable matter of Evening Primrose oil, and the composition was identified and quantified by GC and GC-MS. The major components of sterols fraction were β-Sitosterol and campesterol. We investigated the ability of sterols from Evening Primrose oil to inhibit the release of different proinflammatory mediators in vitro by murine peritoneal macrophages stimulated with lipopolysaccharide. Sterols significantly and dose-dependently decreased nitric oxide production. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression. Sterols also reduced tumor necrosis factor-α, interleukine 1β and tromboxane B₂. However, sterols did not reduce prostaglandin E₂. The reduction of eicosanoid release was related to the inhibition of cyclooxygenase-2 expression. These results showed that sterols may have a protective effect on some mediators involved in inflammatory damage development, suggesting its potential value as a putative functional component of Evening Primrose oil.

  17. MicroRNA and transcription factor mediated regulatory network for ovarian cancer: regulatory network of ovarian cancer.

    Science.gov (United States)

    Ying, Huanchun; Lv, Jing; Ying, Tianshu; Li, Jun; Yang, Qing; Ma, Yuan

    2013-10-01

    A better understanding on the regulatory interactions of microRNA (miRNA) target genes and transcription factor (TF) target genes in ovarian cancer may be conducive for developing early diagnosis strategy. Thus, gene expression data and miRNA expression data were downloaded from The Cancer Genome Atlas in this study. Differentially expressed genes and miRNAs were selected out with t test, and Gene Ontology enrichment analysis was performed with DAVID tools. Regulatory interactions were retrieved from miRTarBase, TRED, and TRANSFAC, and then networks for miRNA target genes and TF target genes were constructed to globally present the mechanisms. As a result, a total of 1,939 differentially expressed genes were identified, and they were enriched in 28 functions, among which cell cycle was affected to the most degree. Besides, 213 differentially expressed miRNAs were identified. Two regulatory networks for miRNA target genes and TF target genes were established and then both were combined, in which E2F transcription factor 1, cyclin-dependent kinase inhibitor 1A, cyclin E1, and miR-16 were the hub genes. These genes may be potential biomarkers for ovarian cancer.

  18. Regulatory Enhancer-Core-Promoter Communication via Transcription Factors and Cofactors.

    Science.gov (United States)

    Zabidi, Muhammad A; Stark, Alexander

    2016-12-01

    Gene expression is regulated by genomic enhancers that recruit transcription factors and cofactors to activate transcription from target core promoters. Over the past years, thousands of enhancers and core promoters in animal genomes have been annotated, and we have learned much about the domain structure in which regulatory genomes are organized in animals. Enhancer-core-promoter targeting occurs at several levels, including regulatory domains, DNA accessibility, and sequence-encoded core-promoter specificities that are likely mediated by different regulatory proteins. We review here current knowledge about enhancer-core-promoter targeting, regulatory communication between enhancers and core promoters, and the protein factors involved. We conclude with an outlook on open questions that we find particularly interesting and that will likely lead to additional insights in the upcoming years.

  19. C26 sterol in a human urine.

    Science.gov (United States)

    Ikekawa, N; Fujimoto, Y; Isiguro, M; Suwa, S; Hirayama, Y; Mizunuma, H

    1979-06-15

    A new C26 sterol, 22-trans-27-norcholesta-5,22-dien-3 beta-ol, was found in the urine of a 6-year-old girl, with a clinical diagnosis of congenital adrenal hyperplasia of the salt losing type, accompanied by symptoms of mixed sex anatomy and skin pigmentation. The structure of the sterol was determined by comparison with the synthetic compound. The sterol was also detected in ther serum. This appears to be the first case in which a C26 sterol has occurred in mammalia.

  20. The sterols of calcareous sponges (Calcarea, Porifera).

    Science.gov (United States)

    Hagemann, Andrea; Voigt, Oliver; Wörheide, Gert; Thiel, Volker

    2008-11-01

    Sponges are sessile suspension-feeding organisms whose internal phylogenetic relationships are still the subject of intense debate. Sterols may have the potential to be used as independent markers to test phylogenetic hypotheses. Twenty representative specimens of calcareous sponges (class Calcarea, phylum Porifera) with a broad coverage within both subclasses Calcinea and Calcaronea were analysed for their sterol content. Two major pseudohomologous series were found, accompanied by some additional sterols. The first series encompassing conventional C(27) to C(29)Delta(5,7,22) sterols represented the major sterols, with ergosterol (ergosta-5,7,22-trien-3beta-ol, C(28)Delta(5,7,22)) being most prominent in many species. The second series consisted of unusual C(27) to C(29)Delta(5,7,9(11),22) sterols. Cholesterol occurred sporadically, mostly in trace amounts. The sterol patterns did not resolve intraclass phylogenetic relationships, namely the distinction between the subclasses, Calcinea and Calcaronea. This pointed towards major calcarean lipid traits being established prior to the separation of subclasses. Furthermore, calcarean sterol patterns clearly differ from those found in Hexactinellida, whereas partial overlap occurred with some Demospongiae. Hence, sterols only partly reflect the phylogenetic separation of Calcarea from both of the other poriferan classes that was proposed by recent molecular work and fatty acid analyses.

  1. Lipid-lowering Activity of Natural and Semi-Synthetic Sterols and Stanols.

    Science.gov (United States)

    Taha, Dhiaa A; Wasan, Ellen K; Wasan, Kishor M; Gershkovich, Pavel

    2015-01-01

    Consumption of plant sterols/ stanols has long been demonstrated to reduce plasma cholesterol levels. The objective of this review is to demonstrate the lipid-lowering activity and anti-atherogenic effects of natural and semi-synthetic plant sterols/ stanols based on evidence from cell-culture studies, animal studies and clinical trials. Additionally, this review highlights certain molecular mechanisms by which plant sterols/ stanols lower plasma cholesterol levels with a special emphasis on factors that affect the cholesterol-lowering activity of plant sterols/stanols. The crystalline nature and the poor oil solubility of these natural products could be important factors that limit their cholesterol-lowering efficiency. Several attempts have been made to improve the cholesterol-lowering activity by enhancing the bioavailability of crystalline sterols and stanols. Approaches involved reduction of the crystal size and/or esterification with fatty acids from vegetable or fish oils. However, the most promising approach in this context is the chemical modification of plant sterols /stanols into water soluble disodium ascorbyl phytostanyl phosphates analogue by esterification with ascorbic acid. This novel semi-synthetic stanol derivative has improved efficacy over natural plant sterols/ stanols and can provide additional benefits by combining the cholesterol-lowering properties of plant stanols with the antioxidant potential of ascorbic acid. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  2. Inferring the role of transcription factors in regulatory networks

    Directory of Open Access Journals (Sweden)

    Le Borgne Michel

    2008-05-01

    Full Text Available Abstract Background Expression profiles obtained from multiple perturbation experiments are increasingly used to reconstruct transcriptional regulatory networks, from well studied, simple organisms up to higher eukaryotes. Admittedly, a key ingredient in developing a reconstruction method is its ability to integrate heterogeneous sources of information, as well as to comply with practical observability issues: measurements can be scarce or noisy. In this work, we show how to combine a network of genetic regulations with a set of expression profiles, in order to infer the functional effect of the regulations, as inducer or repressor. Our approach is based on a consistency rule between a network and the signs of variation given by expression arrays. Results We evaluate our approach in several settings of increasing complexity. First, we generate artificial expression data on a transcriptional network of E. coli extracted from the literature (1529 nodes and 3802 edges, and we estimate that 30% of the regulations can be annotated with about 30 profiles. We additionally prove that at most 40.8% of the network can be inferred using our approach. Second, we use this network in order to validate the predictions obtained with a compendium of real expression profiles. We describe a filtering algorithm that generates particularly reliable predictions. Finally, we apply our inference approach to S. cerevisiae transcriptional network (2419 nodes and 4344 interactions, by combining ChIP-chip data and 15 expression profiles. We are able to detect and isolate inconsistencies between the expression profiles and a significant portion of the model (15% of all the interactions. In addition, we report predictions for 14.5% of all interactions. Conclusion Our approach does not require accurate expression levels nor times series. Nevertheless, we show on both data, real and artificial, that a relatively small number of perturbation experiments are enough to determine

  3. Depot sterols in comparisons with structural sterols in Cancer pagurus and Eriocheir sinensis

    NARCIS (Netherlands)

    Zandee, D.I.; Kruitwagen, E.C.J.

    1975-01-01

    The differences in sterol content and sterol composition between the midgut gland and remaining parts (structural lipids) of male and female specimens of Cancer pagurus and Eriocheir sinensis are investigated. There are no differences in sterol content in the structural lipids between male and femal

  4. Reconstruction and topological characterization of the sigma factor regulatory network of Mycobacterium tuberculosis.

    Science.gov (United States)

    Chauhan, Rinki; Ravi, Janani; Datta, Pratik; Chen, Tianlong; Schnappinger, Dirk; Bassler, Kevin E; Balázsi, Gábor; Gennaro, Maria Laura

    2016-03-31

    Accessory sigma factors, which reprogram RNA polymerase to transcribe specific gene sets, activate bacterial adaptive responses to noxious environments. Here we reconstruct the complete sigma factor regulatory network of the human pathogen Mycobacterium tuberculosis by an integrated approach. The approach combines identification of direct regulatory interactions between M. tuberculosis sigma factors in an E. coli model system, validation of selected links in M. tuberculosis, and extensive literature review. The resulting network comprises 41 direct interactions among all 13 sigma factors. Analysis of network topology reveals (i) a three-tiered hierarchy initiating at master regulators, (ii) high connectivity and (iii) distinct communities containing multiple sigma factors. These topological features are likely associated with multi-layer signal processing and specialized stress responses involving multiple sigma factors. Moreover, the identification of overrepresented network motifs, such as autoregulation and coregulation of sigma and anti-sigma factor pairs, provides structural information that is relevant for studies of network dynamics.

  5. Loregic: A Method to Characterize the Cooperative Logic of Regulatory Factors

    Science.gov (United States)

    Wang, Daifeng; Yan, Koon-Kiu; Sisu, Cristina; Cheng, Chao; Rozowsky, Joel; Meyerson, William; Gerstein, Mark B.

    2015-01-01

    The topology of the gene-regulatory network has been extensively analyzed. Now, given the large amount of available functional genomic data, it is possible to go beyond this and systematically study regulatory circuits in terms of logic elements. To this end, we present Loregic, a computational method integrating gene expression and regulatory network data, to characterize the cooperativity of regulatory factors. Loregic uses all 16 possible two-input-one-output logic gates (e.g. AND or XOR) to describe triplets of two factors regulating a common target. We attempt to find the gate that best matches each triplet’s observed gene expression pattern across many conditions. We make Loregic available as a general-purpose tool (github.com/gersteinlab/loregic). We validate it with known yeast transcription-factor knockout experiments. Next, using human ENCODE ChIP-Seq and TCGA RNA-Seq data, we are able to demonstrate how Loregic characterizes complex circuits involving both proximally and distally regulating transcription factors (TFs) and also miRNAs. Furthermore, we show that MYC, a well-known oncogenic driving TF, can be modeled as acting independently from other TFs (e.g., using OR gates) but antagonistically with repressing miRNAs. Finally, we inter-relate Loregic’s gate logic with other aspects of regulation, such as indirect binding via protein-protein interactions, feed-forward loop motifs and global regulatory hierarchy. PMID:25884877

  6. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the modification of the authorisation of a health claim related to plant sterol esters and lowering blood LDL-cholesterol; high blood LDL-cholesterol is a risk factor in the development

    DEFF Research Database (Denmark)

    Tetens, Inge

    of a health claim related to plant sterol esters and lowering blood LDL-cholesterol (high blood LDL-cholesterol is a risk factor in the development of (coronary) heart disease), pursuant to Article 14 of Regulation (EC) No 1924/2006. The applicant requested an extension of the conditions of use to powder...... supplements to be diluted in water at a dose of 2 g per day, which would lower blood LDL-cholesterol concentrations by “5.4-8.1 %” after six weeks of daily consumption. Plant sterol esters are sufficiently characterised. Lowering blood LDL-cholesterol concentrations is a beneficial physiological effect...... and elevated blood LDL-cholesterol concentration is a risk factor for coronary heart disease. The target population is subjects who need and want to lower their blood cholesterol. In weighing the evidence, the Panel took into account that only one human intervention study showed a reduction in blood LDL-cholesterol...

  7. Bioorthogonal probes for imaging sterols in cells.

    Science.gov (United States)

    Jao, Cindy Y; Nedelcu, Daniel; Lopez, Lyle V; Samarakoon, Thilani N; Welti, Ruth; Salic, Adrian

    2015-03-01

    Cholesterol is a fundamental lipid component of eukaryotic membranes and a precursor of potent signaling molecules, such as oxysterols and steroid hormones. Cholesterol and oxysterols are also essential for Hedgehog signaling, a pathway critical in embryogenesis and cancer. Despite their importance, the use of imaging sterols in cells is currently very limited. We introduce a robust and versatile method for sterol microscopy based on C19 alkyne cholesterol and oxysterol analogues. These sterol analogues are fully functional; they rescue growth of cholesterol auxotrophic cells and faithfully recapitulate the multiple roles that sterols play in Hedgehog signal transduction. Alkyne sterol analogues incorporate efficiently into cellular membranes and can be imaged with high resolution after copper(I)-catalyzed azide-alkyne cycloaddition reaction with fluorescent azides. We demonstrate the use of alkyne sterol probes for visualizing the subcellular distribution of cholesterol and for two-color imaging of sterols and choline phospholipids. Our imaging strategy should be broadly applicable to studying the role of sterols in normal physiology and disease.

  8. Dietary plant sterols accumulate in the brain

    NARCIS (Netherlands)

    Jansen, PJ; Lutjohann, D; Abildayeva, K; Vanmierlo, T; Plosch, T; Plat, J; von Bergmann, K; Groen, AK; Ramaekers, FCS; Kuipers, F; Mulder, M

    2006-01-01

    Dietary plant sterols and cholesterol have a comparable chemical structure. It is generally assumed that cholesterol and plant sterols do not cross the blood-brain barrier, but quantitative data are lacking. Here, we report that mice deficient for ATP-binding cassette transporter G5 (Abcg5) or Abcg8

  9. DMPD: Type I interferon [corrected] gene induction by the interferon regulatory factorfamily of transcription factors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16979567 Type I interferon [corrected] gene induction by the interferon regulatory factorfamily...ng) (.svg) (.html) (.csml) Show Type I interferon [corrected] gene induction by the interferon regulatory factorfamily...orrected] gene induction by the interferon regulatory factorfamily of transcription factors. Authors Honda K

  10. Comparative molecular modelling of biologically active sterols

    Science.gov (United States)

    Baran, Mariusz; Mazerski, Jan

    2015-04-01

    Membrane sterols are targets for a clinically important antifungal agent - amphotericin B. The relatively specific antifungal action of the drug is based on a stronger interaction of amphotericin B with fungal ergosterol than with mammalian cholesterol. Conformational space occupied by six sterols has been defined using the molecular dynamics method to establish if the conformational features correspond to the preferential interaction of amphotericin B with ergosterol as compared with cholesterol. The compounds studied were chosen on the basis of structural features characteristic for cholesterol and ergosterol and on available experimental data on the ability to form complexes with the antibiotic. Statistical analysis of the data obtained has been performed. The results show similarity of the conformational spaces occupied by all the sterols tested. This suggests that the conformational differences of sterol molecules are not the major feature responsible for the differential sterol - drug affinity.

  11. An information transmission model for transcription factor binding at regulatory DNA sites.

    Science.gov (United States)

    Tan, Mingfeng; Yu, Dong; Jin, Yuan; Dou, Lei; Li, Beiping; Wang, Yuelan; Yue, Junjie; Liang, Long

    2012-06-06

    Computational identification of transcription factor binding sites (TFBSs) is a rapid, cost-efficient way to locate unknown regulatory elements. With increased potential for high-throughput genome sequencing, the availability of accurate computational methods for TFBS prediction has never been as important as it currently is. To date, identifying TFBSs with high sensitivity and specificity is still an open challenge, necessitating the development of novel models for predicting transcription factor-binding regulatory DNA elements. Based on the information theory, we propose a model for transcription factor binding of regulatory DNA sites. Our model incorporates position interdependencies in effective ways. The model computes the information transferred (TI) between the transcription factor and the TFBS during the binding process and uses TI as the criterion to determine whether the sequence motif is a possible TFBS. Based on this model, we developed a computational method to identify TFBSs. By theoretically proving and testing our model using both real and artificial data, we found that our model provides highly accurate predictive results. In this study, we present a novel model for transcription factor binding regulatory DNA sites. The model can provide an increased ability to detect TFBSs.

  12. Mapping and Dynamics of Regulatory DNA and Transcription Factor Networks in A. thaliana

    Directory of Open Access Journals (Sweden)

    Alessandra M. Sullivan

    2014-09-01

    Full Text Available Our understanding of gene regulation in plants is constrained by our limited knowledge of plant cis-regulatory DNA and its dynamics. We mapped DNase I hypersensitive sites (DHSs in A. thaliana seedlings and used genomic footprinting to delineate ∼700,000 sites of in vivo transcription factor (TF occupancy at nucleotide resolution. We show that variation associated with 72 diverse quantitative phenotypes localizes within DHSs. TF footprints encode an extensive cis-regulatory lexicon subject to recent evolutionary pressures, and widespread TF binding within exons may have shaped codon usage patterns. The architecture of A. thaliana TF regulatory networks is strikingly similar to that of animals in spite of diverged regulatory repertoires. We analyzed regulatory landscape dynamics during heat shock and photomorphogenesis, disclosing thousands of environmentally sensitive elements and enabling mapping of key TF regulatory circuits underlying these fundamental responses. Our results provide an extensive resource for the study of A. thaliana gene regulation and functional biology.

  13. Sterols and sterol oxides in the potato products, and sterols in the vegetable oils used for industrial frying operations

    Directory of Open Access Journals (Sweden)

    Dutta, Paresh Chandra

    1996-04-01

    Full Text Available The objective of this study was to determine the composition of sterols in vegetable oils used in industrial frying operations, and sterols and sterol oxides in the fried potato products. The sterols and sterol oxides were enriched by saponification of oils and by solid phase extraction. Preparative thin layer chromatography, capillary gas chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy, were used to give qualitative and quantitative data. The results revealed that the content of desmethylsterols in palm oil, sunflower oil, high oleic sunflower oil, and rapeseed oil/palm oil blend were, 790, 4501, 3550, and 4497 ppm, respectively. Sitosterol was the major desmethylsterol in all samples. Palm oil also contained the lowest levels of total unsaponifiables. The sterols and unsaponifiable contents in sunflower oil were, to some extent, higher than in higholeic sunflower oil. The compositions of sterols after two days of frying were neither markedly different in the oils nor in the potato products fried in these oils compared with the original oils. Isomerised sterols were tentatively quantified to account for 10 ppm, 50 ppm and 20 ppm, in rapeseed oil/palm oil blend, sunflower oil, and high-oleic sunflower oils, respectively. Lipids extracted from French fries prepared in rapeseed oil/palm oil blend contained the highest levels of total sterol oxides, 191 ppm, and epoxides of both sitosterol and campesterol were the major contributors, together at a level of 172 ppm. On the other hand, lipids extracted from French fries prepared in sunflower oil and high-oleic sunflower oil contained 7α-hydroxy-, 7β-hydroxy-, 7-keto- and both epimers of epoxysitosterol, generally in equal amounts. All samples also contained small amounts of different oxidation products of campesterol and stigmasterol.

  14. Systematic genetic analysis of transcription factors to map the fission yeast transcription-regulatory network.

    Science.gov (United States)

    Chua, Gordon

    2013-12-01

    Mapping transcriptional-regulatory networks requires the identification of target genes, binding specificities and signalling pathways of transcription factors. However, the characterization of each transcription factor sufficiently for deciphering such networks remains laborious. The recent availability of overexpression and deletion strains for almost all of the transcription factor genes in the fission yeast Schizosaccharomyces pombe provides a valuable resource to better investigate transcription factors using systematic genetics. In the present paper, I review and discuss the utility of these strain collections combined with transcriptome profiling and genome-wide chromatin immunoprecipitation to identify the target genes of transcription factors.

  15. Thresholds for sterol-limited growth of Daphnia magna: a comparative approach using 10 different sterols.

    Science.gov (United States)

    Martin-Creuzburg, Dominik; Oexle, Sarah; Wacker, Alexander

    2014-09-01

    Arthropods are incapable of synthesizing sterols de novo and thus require a dietary source to cover their physiological demands. The most prominent sterol in animal tissues is cholesterol, which is an indispensable structural component of cell membranes and serves as precursor for steroid hormones. Instead of cholesterol, plants and algae contain a variety of different phytosterols. Consequently, herbivorous arthropods have to metabolize dietary phytosterols to cholesterol to meet their requirements for growth and reproduction. Here, we investigated sterol-limited growth responses of the freshwater herbivore Daphnia magna by supplementing a sterol-free diet with increasing amounts of 10 different phytosterols and comparing thresholds for sterol-limited growth. In addition, we analyzed the sterol composition of D. magna to explore sterol metabolic constraints and bioconversion capacities. We show that dietary phytosterols strongly differ in their potential to support somatic growth of D. magna. The dietary threshold concentrations obtained by supplementing the different sterols cover a wide range (3.5-34.4 μg mg C(-1)) and encompass the one for cholesterol (8.9 μg mg C(-1)), indicating that certain phytosterols are more efficient in supporting somatic growth than cholesterol (e.g., fucosterol, brassicasterol) while others are less efficient (e.g., dihydrocholesterol, lathosterol). The dietary sterol concentration gradients revealed that the poor quality of particular sterols can be alleviated partially by increasing dietary concentrations, and that qualitative differences among sterols are most pronounced at low to moderate dietary concentrations. We infer that the dietary sterol composition has to be considered in zooplankton nutritional ecology to accurately assess potential sterol limitations under field conditions.

  16. Non-cholesterol Sterols in the Diagnosis and Treatment of Dyslipidemias: A Review.

    Science.gov (United States)

    Baila-Rueda, Lucía; Cenarro, Ana; Civeira, Fernando

    2016-01-01

    Non-cholesterol sterols have been used as markers of cholesterol intestinal absorption and hepatic synthesis, leading to a better understanding of cholesterol homeostasis in humans. This review discusses the main noncholesterol sterols that are clinically useful, different methods to quantify the factors associated with blood concentration, and the potential role of non-cholesterol sterols in the diagnosis and treatment of different types of dyslipidemia. The main indication is the use of non-cholesterol sterols for the diagnosis of rare diseases associated with defects in cholesterol synthesis or anomalies in the absorption and/or elimination of phytosterols. However, other potential uses, including the diagnosis of certain hypercholesterolemias and the individualization of lipid-lowering therapies, are promising as they could help treat a wider population.

  17. Sterols in spermatogenesis and sperm maturation

    Science.gov (United States)

    Keber, Rok; Rozman, Damjana; Horvat, Simon

    2013-01-01

    Mammalian spermatogenesis is a complex developmental program in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. One intriguing aspect of sperm production is the dynamic change in membrane lipid composition that occurs throughout spermatogenesis. Cholesterol content, as well as its intermediates, differs vastly between the male reproductive system and nongonadal tissues. Accumulation of cholesterol precursors such as testis meiosis-activating sterol and desmosterol is observed in testes and spermatozoa from several mammalian species. Moreover, cholesterogenic genes, especially meiosis-activating sterol-producing enzyme cytochrome P450 lanosterol 14α-demethylase, display stage-specific expression patterns during spermatogenesis. Discrepancies in gene expression patterns suggest a complex temporal and cell-type specific regulation of sterol compounds during spermatogenesis, which also involves dynamic interactions between germ and Sertoli cells. The functional importance of sterol compounds in sperm production is further supported by the modulation of sterol composition in spermatozoal membranes during epididymal transit and in the female reproductive tract, which is a prerequisite for successful fertilization. However, the exact role of sterols in male reproduction is unknown. This review discusses sterol dynamics in sperm maturation and describes recent methodological advances that will help to illuminate the complexity of sperm formation and function. PMID:23093550

  18. Sterol-Rich Membrane Domains Define Fission Yeast Cell Polarity.

    Science.gov (United States)

    Makushok, Tatyana; Alves, Paulo; Huisman, Stephen Michiel; Kijowski, Adam Rafal; Brunner, Damian

    2016-05-19

    Cell polarization is crucial for the functioning of all organisms. The cytoskeleton is central to the process but its role in symmetry breaking is poorly understood. We study cell polarization when fission yeast cells exit starvation. We show that the basis of polarity generation is de novo sterol biosynthesis, cell surface delivery of sterols, and their recruitment to the cell poles. This involves four phases occurring independent of the polarity factor cdc42p. Initially, multiple, randomly distributed sterol-rich membrane (SRM) domains form at the plasma membrane, independent of the cytoskeleton and cell growth. These domains provide platforms on which the growth and polarity machinery assembles. SRM domains are then polarized by the microtubule-dependent polarity factor tea1p, which prepares for monopolar growth initiation and later switching to bipolar growth. SRM polarization requires F-actin but not the F-actin organizing polarity factors for3p and bud6p. We conclude that SRMs are key to cell polarization.

  19. Interferon regulatory factor 1 is required for mouse Gbp gene activation by gamma interferon.

    OpenAIRE

    1995-01-01

    Full-scale transcriptional activation of the mouse Gbp genes by gamma interferon (IFN-gamma) requires protein synthesis in embryonic fibroblasts. Although the Gbp-1 and Gbp-2 promoters contain binding sites for transcription factors Stat1 and IFN regulatory factor 1 (IRF-1), deletion analysis revealed that the Stat1 binding site is dispensable for IFN-gamma inducibility of Gbp promoter constructs in transfected fibroblasts. However, activation of the mouse Gbp promoter by IFN-gamma requires t...

  20. From System-Wide Differential Gene Expression to Perturbed Regulatory Factors: A Combinatorial Approach.

    Directory of Open Access Journals (Sweden)

    Gaurang Mahajan

    Full Text Available High-throughput experiments such as microarrays and deep sequencing provide large scale information on the pattern of gene expression, which undergoes extensive remodeling as the cell dynamically responds to varying environmental cues or has its function disrupted under pathological conditions. An important initial step in the systematic analysis and interpretation of genome-scale expression alteration involves identification of a set of perturbed transcriptional regulators whose differential activity can provide a proximate hypothesis to account for these transcriptomic changes. In the present work, we propose an unbiased and logically natural approach to transcription factor enrichment. It involves overlaying a list of experimentally determined differentially expressed genes on a background regulatory network coming from e.g. literature curation or computational motif scanning, and identifying that subset of regulators whose aggregated target set best discriminates between the altered and the unaffected genes. In other words, our methodology entails testing of all possible regulatory subnetworks, rather than just the target sets of individual regulators as is followed in most standard approaches. We have proposed an iterative search method to efficiently find such a combination, and benchmarked it on E. coli microarray and regulatory network data available in the public domain. Comparative analysis carried out on artificially generated differential expression profiles, as well as empirical factor overexpression data for M. tuberculosis, shows that our methodology provides marked improvement in accuracy of regulatory inference relative to the standard method that involves evaluating factor enrichment in an individual manner.

  1. From System-Wide Differential Gene Expression to Perturbed Regulatory Factors: A Combinatorial Approach.

    Science.gov (United States)

    Mahajan, Gaurang; Mande, Shekhar C

    2015-01-01

    High-throughput experiments such as microarrays and deep sequencing provide large scale information on the pattern of gene expression, which undergoes extensive remodeling as the cell dynamically responds to varying environmental cues or has its function disrupted under pathological conditions. An important initial step in the systematic analysis and interpretation of genome-scale expression alteration involves identification of a set of perturbed transcriptional regulators whose differential activity can provide a proximate hypothesis to account for these transcriptomic changes. In the present work, we propose an unbiased and logically natural approach to transcription factor enrichment. It involves overlaying a list of experimentally determined differentially expressed genes on a background regulatory network coming from e.g. literature curation or computational motif scanning, and identifying that subset of regulators whose aggregated target set best discriminates between the altered and the unaffected genes. In other words, our methodology entails testing of all possible regulatory subnetworks, rather than just the target sets of individual regulators as is followed in most standard approaches. We have proposed an iterative search method to efficiently find such a combination, and benchmarked it on E. coli microarray and regulatory network data available in the public domain. Comparative analysis carried out on artificially generated differential expression profiles, as well as empirical factor overexpression data for M. tuberculosis, shows that our methodology provides marked improvement in accuracy of regulatory inference relative to the standard method that involves evaluating factor enrichment in an individual manner.

  2. metagene Profiles Analyses Reveal Regulatory Element's Factor-Specific Recruitment Patterns.

    Science.gov (United States)

    Joly Beauparlant, Charles; Lamaze, Fabien C; Deschênes, Astrid; Samb, Rawane; Lemaçon, Audrey; Belleau, Pascal; Bilodeau, Steve; Droit, Arnaud

    2016-08-01

    ChIP-Sequencing (ChIP-Seq) provides a vast amount of information regarding the localization of proteins across the genome. The aggregation of ChIP-Seq enrichment signal in a metagene plot is an approach commonly used to summarize data complexity and to obtain a high level visual representation of the general occupancy pattern of a protein. Here we present the R package metagene, the graphical interface Imetagene and the companion package similaRpeak. Together, they provide a framework to integrate, summarize and compare the ChIP-Seq enrichment signal from complex experimental designs. Those packages identify and quantify similarities or dissimilarities in patterns between large numbers of ChIP-Seq profiles. We used metagene to investigate the differential occupancy of regulatory factors at noncoding regulatory regions (promoters and enhancers) in relation to transcriptional activity in GM12878 B-lymphocytes. The relationships between occupancy patterns and transcriptional activity suggest two different mechanisms of action for transcriptional control: i) a "gradient effect" where the regulatory factor occupancy levels follow transcription and ii) a "threshold effect" where the regulatory factor occupancy levels max out prior to reaching maximal transcription. metagene, Imetagene and similaRpeak are implemented in R under the Artistic license 2.0 and are available on Bioconductor.

  3. metagene Profiles Analyses Reveal Regulatory Element’s Factor-Specific Recruitment Patterns

    Science.gov (United States)

    Samb, Rawane; Lemaçon, Audrey; Bilodeau, Steve; Droit, Arnaud

    2016-01-01

    ChIP-Sequencing (ChIP-Seq) provides a vast amount of information regarding the localization of proteins across the genome. The aggregation of ChIP-Seq enrichment signal in a metagene plot is an approach commonly used to summarize data complexity and to obtain a high level visual representation of the general occupancy pattern of a protein. Here we present the R package metagene, the graphical interface Imetagene and the companion package similaRpeak. Together, they provide a framework to integrate, summarize and compare the ChIP-Seq enrichment signal from complex experimental designs. Those packages identify and quantify similarities or dissimilarities in patterns between large numbers of ChIP-Seq profiles. We used metagene to investigate the differential occupancy of regulatory factors at noncoding regulatory regions (promoters and enhancers) in relation to transcriptional activity in GM12878 B-lymphocytes. The relationships between occupancy patterns and transcriptional activity suggest two different mechanisms of action for transcriptional control: i) a “gradient effect” where the regulatory factor occupancy levels follow transcription and ii) a “threshold effect” where the regulatory factor occupancy levels max out prior to reaching maximal transcription. metagene, Imetagene and similaRpeak are implemented in R under the Artistic license 2.0 and are available on Bioconductor. PMID:27538250

  4. Biofuels. Altered sterol composition renders yeast thermotolerant

    DEFF Research Database (Denmark)

    Caspeta, Luis; Chen, Yun; Ghiaci, Payam

    2014-01-01

    adaptive laboratory evolution to select yeast strains with improved growth and ethanol production at ≥40°C. Sequencing of the whole genome, genome-wide gene expression, and metabolic-flux analyses revealed a change in sterol composition, from ergosterol to fecosterol, caused by mutations in the C-5 sterol...... desaturase gene, and increased expression of genes involved in sterol biosynthesis. Additionally, large chromosome III rearrangements and mutations in genes associated with DNA damage and respiration were found, but contributed less to the thermotolerant phenotype....

  5. Controllability analysis of transcriptional regulatory networks reveals circular control patterns among transcription factors

    DEFF Research Database (Denmark)

    Österlund, Tobias; Bordel, Sergio; Nielsen, Jens

    2015-01-01

    Transcriptional regulation is the most committed type of regulation in living cells where transcription factors (TFs) control the expression of their target genes and TF expression is controlled by other TFs forming complex transcriptional regulatory networks that can be highly interconnected. Here...... we analyze the topology and organization of nine transcriptional regulatory networks for E. coli, yeast, mouse and human, and we evaluate how the structure of these networks influences two of their key properties, namely controllability and stability. We calculate the controllability for each network...... as a measure of the organization and interconnectivity of the network. We find that the number of driver nodes n(D) needed to control the whole network is 64% of the TFs in the E. coli transcriptional regulatory network in contrast to only 17% for the yeast network, 4% for the mouse network and 8...

  6. Comparative Analysis of Regulatory Motif Discovery Tools for Transcription Factor Binding Sites

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the post-genomic era, identification of specific regulatory motifs or transcription factor binding sites (TFBSs) in non-coding DNA sequences, which is essential to elucidate transcriptional regulatory networks, has emerged as an obstacle that frustrates many researchers. Consequently, numerous motif discovery tools and correlated databases have been applied to solving this problem. However, these existing methods, based on different computational algorithms, show diverse motif prediction efficiency in non-coding DNA sequences. Therefore, understanding the similarities and differences of computational algorithms and enriching the motif discovery literatures are important for users to choose the most appropriate one among the online available tools. Moreover, there still lacks credible criterion to assess motif discovery tools and instructions for researchers to choose the best according to their own projects. Thus integration of the related resources might be a good approach to improve accuracy of the application. Recent studies integrate regulatory motif discovery tools with experimental methods to offer a complementary approach for researchers, and also provide a much-needed model for current researches on transcriptional regulatory networks. Here we present a comparative analysis of regulatory motif discovery tools for TFBSs.

  7. Scientific and regulatory standards for assessing product performance using the similarity factor, f2.

    Science.gov (United States)

    Stevens, Ruth E; Gray, Vivian; Dorantes, Angelica; Gold, Lynn; Pham, Loan

    2015-03-01

    The similarity factor, f2, measures the sameness of dissolution profiles. The following commentary is an overview of discussions and presentations from a group of industry and US regulatory experts that have integrated the science and regulatory research and practice for assessing product performance, particularly for modified-release (MR) dosage forms, using f2. For a drug development sponsor or applicant with an orally complex dosage formulation, it is critical to understand dissolution methods and the similarity factor and how and/or when to apply it in their NDA, ANDA, or PMA submission. As part of any regulatory submission, it is critical to justify that the product performance has not been impacted by any change in the manufacturing process and/or the delayed and/or prolonged drug release characteristics compared to a similar conventional or another orally complex dosage form. The purposes of this document are (1) to provide a description of appropriate dissolution methods, how is the f2 calculated and how it can be used to justify product performance similarity, or not; (2) to provide an overview of alternative methods available for dissolution profile comparisons, and (3) to illustrate how applying these concepts in a focused way supports approval of submissions and regulatory dossiers and aligns them with on-going science and regulatory initiatives. A case study will be used as an example to demonstrate how dissolution testing and the f2 calculation results can impact regulatory outcomes from an NDA (505(b)(1)), NDA (505(b)(2)), ANDA (505(j)), supplemental NDAs/ANDAs, or PMA perspective.

  8. Biosynthesis and composition of sterols and sterol esters in the land snail Cepaea nemoralis (L.) (gastropoda, pulmonata, stylommatophora)

    NARCIS (Netherlands)

    Horst, D.J. van der; Voogt, P.A.

    1972-01-01

    1. 1. The biosynthesis and composition of sterols and sterol esters were studied in the land snail Cepaea nemoralis after injection of Na-1-14C-acetate. 2. 2. Free and esterified sterols appeared to be synthesized by the animals, whilst the specific radioactivity of the sterols from the esters was

  9. Biosynthesis and composition of sterols and sterol esters in the land snail Cepaea nemoralis (L.) (gastropoda, pulmonata, stylommatophora)

    NARCIS (Netherlands)

    Horst, D.J. van der; Voogt, P.A.

    1972-01-01

    1. 1. The biosynthesis and composition of sterols and sterol esters were studied in the land snail Cepaea nemoralis after injection of Na-1-14C-acetate. 2. 2. Free and esterified sterols appeared to be synthesized by the animals, whilst the specific radioactivity of the sterols from the esters was

  10. Regulation of squalene synthase, a key enzyme of sterol biosynthesis, in tobacco.

    Science.gov (United States)

    Devarenne, Timothy P; Ghosh, Anirban; Chappell, Joe

    2002-07-01

    Squalene synthase (SS) represents a putative branch point in the isoprenoid biosynthetic pathway capable of diverting carbon flow specifically to the biosynthesis of sterols and, hence, is considered a potential regulatory point for sterol metabolism. For example, when plant cells grown in suspension culture are challenged with fungal elicitors, suppression of sterol biosynthesis has been correlated with a reduction in SS enzyme activity. The current study sought to correlate changes in SS enzyme activity with changes in the level of the corresponding protein and mRNA. Using an SS-specific antibody, the initial suppression of SS enzyme activity in elicitor-challenged cells was not reflected by changes in the absolute level of the corresponding polypeptide, implicating a post-translational control mechanism for this enzyme activity. In comparison, the absolute level of the SS mRNA did decrease approximately 5-fold in the elicitor-treated cells, which is suggestive of decreased transcription of the SS gene. Study of SS in intact plants was also initiated by measuring the level of SS enzyme activity, the level of the corresponding protein, and the expression of SS gene promoter-reporter gene constructs in transgenic plants. SS enzyme activity, polypeptide level, and gene expression were all localized predominately to the shoot apical meristem, with much lower levels observed in leaves and roots. These later results suggest that sterol biosynthesis is localized to the apical meristems and that apical meristems may be a source of sterols for other plant tissues.

  11. Patterns of Positive Selection of the Myogenic Regulatory Factor Gene Family in Vertebrates

    Science.gov (United States)

    Zhao, Xiao; Yu, Qi; Huang, Ling; Liu, Qing-Xin

    2014-01-01

    The functional divergence of transcriptional factors is critical in the evolution of transcriptional regulation. However, the mechanism of functional divergence among these factors remains unclear. Here, we performed an evolutionary analysis for positive selection in members of the myogenic regulatory factor (MRF) gene family of vertebrates. We selected 153 complete vertebrate MRF nucleotide sequences from our analyses, which revealed substantial evidence of positive selection. Here, we show that sites under positive selection were more frequently detected and identified from the genes encoding the myogenic differentiation factors (MyoG and Myf6) than the genes encoding myogenic determination factors (Myf5 and MyoD). Additionally, the functional divergence within the myogenic determination factors or differentiation factors was also under positive selection pressure. The positive selection sites were more frequently detected from MyoG and MyoD than Myf6 and Myf5, respectively. Amino acid residues under positive selection were identified mainly in their transcription activation domains and on the surface of protein three-dimensional structures. These data suggest that the functional gain and divergence of myogenic regulatory factors were driven by distinct positive selection of their transcription activation domains, whereas the function of the DNA binding domains was conserved in evolution. Our study evaluated the mechanism of functional divergence of the transcriptional regulation factors within a family, whereby the functions of their transcription activation domains diverged under positive selection during evolution. PMID:24651579

  12. Transforming growth factor-beta-induced regulatory T cells referee inflammatory and autoimmune diseases.

    Science.gov (United States)

    Wahl, Sharon M; Chen, Wanjun

    2005-01-01

    Naturally occurring CD4+CD25+ regulatory T cells mediate immune suppression to limit immunopathogenesis associated with chronic inflammation, persistent infections and autoimmune diseases. Their mode of suppression is contact-dependent, antigen-nonspecific and involves a nonredundant contribution from the cytokine transforming growth factor (TGF)-beta. Not only can TGF-beta mediate cell-cell suppression between the regulatory T cells and CD4+CD25- or CD8+ T cells, but new evidence also reveals its role in the conversion of CD4+CD25- T cells, together with TCR antigen stimulation, into the regulatory phenotype. Elemental to this conversion process is induction of expression of the forkhead transcription factor, Foxp3. This context-dependent coercion of naive CD4+ T cells into a powerful subset of regulatory cells provides a window into potential manipulation of these cells to orchestrate therapeutic intervention in diseases characterized by inadequate suppression, as well as a promising means of controlling pathologic situations in which excessive suppression dominates.

  13. Characterizing the interplay between multiple levels of organization within bacterial sigma factor regulatory networks.

    Science.gov (United States)

    Qiu, Yu; Nagarajan, Harish; Embree, Mallory; Shieu, Wendy; Abate, Elisa; Juárez, Katy; Cho, Byung-Kwan; Elkins, James G; Nevin, Kelly P; Barrett, Christian L; Lovley, Derek R; Palsson, Bernhard O; Zengler, Karsten

    2013-01-01

    Bacteria contain multiple sigma factors, each targeting diverse, but often overlapping sets of promoters, thereby forming a complex network. The layout and deployment of such a sigma factor network directly impacts global transcriptional regulation and ultimately dictates the phenotype. Here we integrate multi-omic data sets to determine the topology, the operational, and functional states of the sigma factor network in Geobacter sulfurreducens, revealing a unique network topology of interacting sigma factors. Analysis of the operational state of the sigma factor network shows a highly modular structure with σ(N) being the major regulator of energy metabolism. Surprisingly, the functional state of the network during the two most divergent growth conditions is nearly static, with sigma factor binding profiles almost invariant to environmental stimuli. This first comprehensive elucidation of the interplay between different levels of the sigma factor network organization is fundamental to characterize transcriptional regulatory mechanisms in bacteria.

  14. Characterizing the interplay betwen mulitple levels of organization within bacterial sigma factor regulatory networks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qiu [University of California, San Diego; Nagarajan, Harish [University of California, San Diego; Embree, Mallory [University of California, San Diego; Shieu, Wendy [University of California, San Diego; Abate, Elisa [University of California, San Diego; Juarez, Katy [Universidad Nacional Autonoma de Mexico (UNAM); Cho, Byung-Kwan [University of California, San Diego; Elkins, James G [ORNL; Nevin, Kelly P. [University of Massachusetts, Amherst; Barrett, Christian [University of California, San Diego; Lovley, Derek [University of Massachusetts, Amherst; Palsson, Bernhard O. [University of California, San Diego; Zengler, Karsten [University of California, San Diego

    2013-01-01

    Bacteria contain multiple sigma factors, each targeting diverse, but often overlapping sets of promoters, thereby forming a complex network. The layout and deployment of such a sigma factor network directly impacts global transcriptional regulation and ultimately dictates the phenotype. Here we integrate multi-omic data sets to determine the topology, the operational, and functional states of the sigma factor network in Geobacter sulfurreducens, revealing a unique network topology of interacting sigma factors. Analysis of the operational state of the sigma factor network shows a highly modular structure with sN being the major regulator of energy metabolism. Surprisingly, the functional state of the network during the two most divergent growth conditions is nearly static, with sigma factor binding profiles almost invariant to environmental stimuli. This first comprehensive elucidation of the interplay between different levels of the sigma factor network organization is fundamental to characterize transcriptional regulatory mechanisms in bacteria.

  15. Sterols from the Madagascar Sponge Fascaplysinopsis sp.

    Directory of Open Access Journals (Sweden)

    Yoel Kashman

    2010-12-01

    Full Text Available The sponge Fascaplysinopsis sp. (order Dictyoceratida, Family Thorectidae from the west coast of Madagascar (Indian Ocean is a particularly rich source of bioactive nitrogenous macrolides. The previous studies on this organism led to the suggestion that the latter should originate from associated microsymbionts. In order to evaluate the influence of microsymbionts on lipid content, 10 samples of Fascaplysinopsis sp. were investigated for their sterol composition. Contrary to the secondary metabolites, the sterol patterns established were qualitatively and quantitatively stable: 14 sterols with different unsaturated nuclei, D5, D7 and D5,7, were identified; the last ones being the main sterols of the investigated sponges. The chemotaxonomic significance of these results for the order Dictyoceratida is also discussed in the context of the literature. The conjugated diene system in D5,7 sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5a,8a-epidioxy sterols. However, in this study, no 5a,8a-epidioxysterols (or only trace amounts were observed. Thus, it was supposed that photo-oxidation was avoided thanks to the natural antioxidants detected in Fascaplysinopsis sp. by both the DPPH and b-caroten bleaching assays.

  16. Sterols from the Madagascar sponge Fascaplysinopsis sp.

    Science.gov (United States)

    Aknin, Maurice; Gros, Emmanuelle; Vacelet, Jean; Kashman, Yoel; Gauvin-Bialecki, Anne

    2010-12-17

    The sponge Fascaplysinopsis sp. (order Dictyoceratida, Family Thorectidae) from the west coast of Madagascar (Indian Ocean) is a particularly rich source of bioactive nitrogenous macrolides. The previous studies on this organism led to the suggestion that the latter should originate from associated microsymbionts. In order to evaluate the influence of microsymbionts on lipid content, 10 samples of Fascaplysinopsis sp. were investigated for their sterol composition. Contrary to the secondary metabolites, the sterol patterns established were qualitatively and quantitatively stable: 14 sterols with different unsaturated nuclei, Δ(5), Δ(7) and Δ(5,7), were identified; the last ones being the main sterols of the investigated sponges. The chemotaxonomic significance of these results for the order Dictyoceratida is also discussed in the context of the literature. The conjugated diene system in Δ(5,7) sterols is known to be unstable and easily photo-oxidized during storage and/or experiments to produce 5α,8α-epidioxy sterols. However, in this study, no 5α,8α-epidioxysterols (or only trace amounts) were observed. Thus, it was supposed that photo-oxidation was avoided thanks to the natural antioxidants detected in Fascaplysinopsis sp. by both the DPPH and β-caroten bleaching assays.

  17. Controllability analysis of transcriptional regulatory networks reveals circular control patterns among transcription factors.

    Science.gov (United States)

    Österlund, Tobias; Bordel, Sergio; Nielsen, Jens

    2015-05-01

    Transcriptional regulation is the most committed type of regulation in living cells where transcription factors (TFs) control the expression of their target genes and TF expression is controlled by other TFs forming complex transcriptional regulatory networks that can be highly interconnected. Here we analyze the topology and organization of nine transcriptional regulatory networks for E. coli, yeast, mouse and human, and we evaluate how the structure of these networks influences two of their key properties, namely controllability and stability. We calculate the controllability for each network as a measure of the organization and interconnectivity of the network. We find that the number of driver nodes nD needed to control the whole network is 64% of the TFs in the E. coli transcriptional regulatory network in contrast to only 17% for the yeast network, 4% for the mouse network and 8% for the human network. The high controllability (low number of drivers needed to control the system) in yeast, mouse and human is due to the presence of internal loops in their regulatory networks where the TFs regulate each other in a circular fashion. We refer to these internal loops as circular control motifs (CCM). The E. coli transcriptional regulatory network, which does not have any CCMs, shows a hierarchical structure of the transcriptional regulatory network in contrast to the eukaryal networks. The presence of CCMs also has influence on the stability of these networks, as the presence of cycles can be associated with potential unstable steady-states where even small changes in binding affinities can cause dramatic rearrangements of the state of the network.

  18. Retinoic acid exerts dual regulatory actions on the expression and nuclear localization of interferon regulatory factor-1.

    Science.gov (United States)

    Luo, Xin M; Ross, A Catharine

    2006-05-01

    Interferon regulatory factor-1 (IRF-1), a transcription factor and tumor suppressor involved in cell growth regulation and immune responses, has been shown to be induced by all-trans retinoic acid (ATRA). However, the factors controlling the cellular location and activity of IRF-1 are not well understood. In this study, we examined the expression of IRF-1 and its nuclear localization, DNA-binding activity, and target gene expression in human mammary epithelial MCF10A cells, a model of breast epithelial cell differentiation and carcinogenesis. Following initial treatment with ATRA, IRF-1 mRNA and protein were induced within 2 hrs, reached a peak (>30-fold induction) at 8 hrs, and declined afterwards. IRF-1 protein was predominantly cytoplasmic during this treatment. Although a second dose of ATRA or Am580 (a related retinoid selective for retinoic acid receptor-alpha [RARalpha]), given 16 hrs after the first dose, restimulated IRF-1 mRNA and protein levels to a similar level to that obtained by the first dose, IRF-1 was predominantly concentrated in the nucleus after restimulation. ATRA and Am580 also increased nuclear RARalpha, whereas retinoid X receptor-alpha (RXRalpha)--a dimerization partner for RARalpha, was localized to the nucleus upon second exposure to ATRA. However, ATRA and Am580 did not regulate the expression or activation of signal transducer and activator of transcription-1 (STAT-1), a transcription factor capable of inducing the expression of IRF-1, indicating an STAT-1-independent mechanism of regulation by ATRA and Am580. The increase in nuclear IRF-1 after retinoid restimulation was accompanied by enhanced binding to an IRF-E DNA response element, and elevated expression of an IRF-1 target gene, 2',5'-oligoadenylate synthetase-2. The dual effect of retinoids in increasing IRF-1 mRNA and protein and in augmenting the nuclear localization of IRF-1 protein may be essential for maximizing the tumor suppressor activity and the immunosurveillance

  19. Plant sterols in food: No consensus in guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Weingärtner, Oliver, E-mail: oweingartner@aol.com [Abteilung für Kardiologie, Klinikum Oldenburg, European Medical School Oldenburg-Groningen, Carl von Ossietzky Universität, Oldenburg (Germany); Baber, Ronny [Institut für Laboratoriumsmedizin, Klinische Chemie und Molekulare Diagnostik, Universität Leipzig, Leipzig (Germany); LIFE – Leipziger Forschungszentrum für Zivilisationserkrankungen, Universität Leipzig, Leipzig (Germany); Teupser, Daniel [Institut für Laboratoriumsmedizin, Ludwig-Maximilians-Universität, München (Germany)

    2014-04-11

    Highlights: • Plant sterols are used as food supplement to reduce serum cholesterol levels. • Reductions in serum cholesterol levels are achieved at the expense of increased plant sterol levels. • The potential atherogenicity of increased serum plant sterol levels is controversially debated. • This dispute is reflected by different guideline recommendations in regard to plant sterols. - Abstract: Plant sterols are supplemented in foods to reduce cardiovascular risk. Randomized controlled trials show 2 g of plant sterols a day reduce serum cholesterol by about 10%. This reduction in serum cholesterol levels is achieved at the expense of increased serum plant sterol levels. Findings in patients with phytosterolemia, in experimental studies and in clinical trials have lead to speculations that plant sterols might be atherogenic. In view of emerging safety issues the role of plant sterols in cardiovascular prevention has become controversial. This review reflects the ongoing controversial scientific debate and points out recent developments in guidelines of national and international societies.

  20. Melissa officinalis essential oil reduces plasma triglycerides in human apolipoprotein E2 transgenic mice by inhibiting sterol regulatory element-binding protein-1c-dependent fatty acid synthesis.

    Science.gov (United States)

    Jun, Hee-Jin; Lee, Ji Hae; Jia, Yaoyao; Hoang, Minh-Hien; Byun, Hanna; Kim, Kyoung Heon; Lee, Sung-Joon

    2012-03-01

    We investigated the hypolipidemic effects of Melissa officinalis essential oil (MOEO) in human APOE2 transgenic mice and lipid-loaded HepG2 cells. Plasma TG concentrations were significantly less in APOE2 mice orally administered MOEO (12.5 μg/d) for 2 wk than in the vehicle-treated group. Cellular TG and cholesterol concentrations were also significantly decreased in a dose- (400 and 800 mg/L) and time- (12 and 24 h) dependent manner in HepG2 cells stimulated with MOEO compared with controls. Mouse hepatic transcriptome analysis suggested MOEO feeding altered several lipid metabolic pathways, including bile acid and cholesterol synthesis and fatty acid metabolism. In HepG2 cells, the rate of fatty acid oxidation, as assessed using [1-(14)C]palmitate, was unaltered; however, the rate of fatty acid synthesis quantified with [1-(14)C]acetate was significantly reduced by treatment with 400 and 800 mg/L MOEO compared with untreated controls. This reduction was due to the decreased expression of SREBP-1c and its responsive genes in fatty acid synthesis, including FAS, SCD1, and ACC1. Subsequent chromatin immunoprecipitation analysis further demonstrated that the binding of p300/CBP-associated factor, a coactivator of SREBP-1c, and histone H3 lysine 14 acetylation at the FAS, SCD1, and ACC1 promoters were significantly reduced in the livers of APOE2 mice and HepG2 cells treated with MOEO compared with their controls. Additionally, MOEO stimulation in HepG2 cells induced bile acid synthesis and reduced the nuclear form of SREBP-2, a key transcription factor in hepatic cholesterol synthesis. These findings suggest that the intake of phytochemicals with pleasant scent could have beneficial metabolic effects.

  1. Comparative analysis of the transcription-factor gene regulatory networks of E. coli and S. cerevisiae

    Directory of Open Access Journals (Sweden)

    Santillán Moisés

    2008-01-01

    Full Text Available Abstract Background The regulatory interactions between transcription factors (TF and regulated genes (RG in a species genome can be lumped together in a single directed graph. The TF's and RG's conform the nodes of this graph, while links are drawn whenever a transcription factor regulates a gene's expression. Projections onto TF nodes can be constructed by linking every two nodes regulating a common gene. Similarly, projections onto RG nodes can be made by linking every two regulated genes sharing at least one common regulator. Recent studies of the connectivity pattern in the transcription-factor regulatory network of many organisms have revealed some interesting properties. However, the differences between TF and RG nodes have not been widely explored. Results After analysing the RG and TF projections of the transcription-factor gene regulatory networks of Escherichia coli and Saccharomyces cerevisiae, we found several common characteristic as well as some noticeable differences. To better understand these differences, we compared the properties of the E. coli and S. cerevisiae RG- and TF-projected networks with those of the corresponding projections built from randomized versions of the original bipartite networks. These last results indicate that the observed differences are mostly due to the very different ratios of TF to RG counts of the E. coli and S. cerevisiae bipartite networks, rather than to their having different connectivity patterns. Conclusion Since E. coli is a prokaryotic organism while S. cerevisiae is eukaryotic, there are important differences between them concerning processing of mRNA before translation, DNA packing, amount of junk DNA, and gene regulation. From the results in this paper we conclude that the most important effect such differences have had on the development of the corresponding transcription-factor gene regulatory networks is their very different ratios of TF to RG numbers. This ratio is more than three

  2. Involvement of the Phospholipid Sterol Acyltransferase1 in Plant Sterol Homeostasis and Leaf Senescence1[W

    Science.gov (United States)

    Bouvier-Navé, Pierrette; Berna, Anne; Noiriel, Alexandre; Compagnon, Vincent; Carlsson, Anders S.; Banas, Antoni; Stymne, Sten; Schaller, Hubert

    2010-01-01

    Genes encoding sterol ester-forming enzymes were recently identified in the Arabidopsis (Arabidopsis thaliana) genome. One belongs to a family of six members presenting homologies with the mammalian Lecithin Cholesterol Acyltransferases. The other one belongs to the superfamily of Membrane-Bound O-Acyltransferases. The physiological functions of these genes, Phospholipid Sterol Acyltransferase1 (PSAT1) and Acyl-CoA Sterol Acyltransferase1 (ASAT1), respectively, were investigated using Arabidopsis mutants. Sterol ester content decreased in leaves of all mutants and was strongly reduced in seeds from plants carrying a PSAT1-deficient mutation. The amount of sterol esters in flowers was very close to that of the wild type for all lines studied. This indicated further functional redundancy of sterol acylation in Arabidopsis. We performed feeding experiments in which we supplied sterol precursors to psat1-1, psat1-2, and asat1-1 mutants. This triggered the accumulation of sterol esters (stored in cytosolic lipid droplets) in the wild type and the asat1-1 lines but not in the psat1-1 and psat1-2 lines, indicating a major contribution of the PSAT1 in maintaining free sterol homeostasis in plant cell membranes. A clear biological effect associated with the lack of sterol ester formation in the psat1-1 and psat1-2 mutants was an early leaf senescence phenotype. Double mutants lacking PSAT1 and ASAT1 had identical phenotypes to psat1 mutants. The results presented here suggest that PSAT1 plays a role in lipid catabolism as part of the intracellular processes at play in the maintenance of leaf viability during developmental aging. PMID:19923239

  3. A Review on the Regulatory Strategy of Human Factors Engineering Consideration in Pakistan Nuclear Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Sohail, Sabir [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Choi, Seong Nam [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-10-15

    In this paper, the legal and regulatory infrastructure available in Pakistan for HFE requirements is assessed, and the methodology for strengthening of legal infrastructure is presented. The regulatory strategy on evaluation of HFE consideration should provide reviewers with guidance on review process. Therefore, the suggested methodology is based on preparation of guidance documents such as checklist, working procedures, S and Gs etc.; incorporation of PRM elements in regulatory system; and finally the development of PRM implementation criteria. Altogether, the scheme provide the enhancement in regulatory infrastructure and also the effective and efficient review process. The Three Mile Island (TMI) accident brought the general consensus among the nuclear community on the integration of human factors engineering (HFE) principles in all phases of nuclear power. This notion has further strengthened after the recent Fukushima nuclear accident. Much effort has been put over to incorporate the lesson learned and continuous technical evolution on HFE to device different standards. The total of 174 ergonomics standards are alone identified by Dul et al. (2004) published by International Organization for Standardization (ISO) and the European Committee for Standardization (CEN) and number of standards and HFE guidelines (S and Gs) are also published by organizations like Institute for Electrical and Electronics Engineering (IEEE), International Electrotechnical Commission (IEC), International Atomic Energy Agency (IAEA), United States Nuclear Regulatory Commission (USNRC), etc. The ambition of effective review on HFE integration in nuclear facility might be accomplished through the development of methodology for systematic implementation of S and Gs. Such kind of methodology would also be beneficial for strengthening the regulatory framework and practices for countries new in the nuclear arena and with small scale nuclear program. The objective of paper is to review the

  4. Effects of the 54G/C polymorphism of sterol regulatory element-binding protein-1c on changes of serum lipid ratios induced by high-carbohydrate/low-fat diet in healthy youth%固醇调节元件结合蛋白-1c基因54G/C多态性对高糖低脂膳食诱导的健康青年人血脂比值的影响

    Institute of Scientific and Technical Information of China (English)

    张珍; 方定志; 龚仁蓉; 杜娟; 汤慧; 黄鑫; 甘婵芬

    2010-01-01

    Objective To investigate the effects of 54G/C polymorphism of sterol regulatory elementbinding protein-1c gene (SREBP-1c)on serum lipid ratios and their response to high-carbohydrate/low-fat(HC/LF) diet in healthy youth. Methods After a regular diet for 7 days of wash-out, 56 healthy youth (22.89±1.80 yrs) were given HC/LF diet for 6 days. The regular diet contained 54% carbohydrate, 15%protein, and 31% fat of the total energy. The HC/LF diet contained 70% carbohydrate, 15% protein, and 15% fat of the total energy. The serum lipids and glucose were measured on the 1st, 8th and 14th days.The ratios of TG/HDL-C, log (TG/HDL-C), TC/HDL-C, and LDL-C/HDL-C were calculated. The 54G/C polymorphism of SREBP-1c gene was analyzed by PCR-RFLP method. Results No significant difference was found in lipid ratios and glucose at baseline and after regular diet in subjects with different genotypes in either the whole studied population or in males or females only. However, after HC/LF diet, LDL-C/HDL-C was significantly lower in females carrying the C allele than those of GG homozygotes (P< 0.05).Compared with those before HC/LF diet, TC/HDL-C and LDL-C/HDL-C were significantly decreased in all the subjects (P<0.05). When gender was taken into account, significant increase of TG/HDL-C and log(TG/HDL-C) was found only in females with GG genotype (P<0.05). All the subjects experienced significant decrease of TC/HDL-C and LDL-C/HDL-C regardless of their genders and genotypes (P<0.05). Conclusion The 54G/C polymorphism of SREBP-1c gene can influence the response of TG/HDL-C and log(TG/HDL-C) to HC/LF diet in females. The C allele may be a protective factor to prevent the increase of TG induced by HC/LF diet in females.%目的 探讨固醇调节元件结合蛋白-1c(sterol regulatory element-binding protein-1c,SREBP-1c)基因54G/C多态性对健康青年血脂比值的影响及在高糖低脂(high-carbohydrate/low-fat,HC/LF)膳食诱导的变化中的作用.方法 对56

  5. Transcriptional control of yeast ribosome biogenesis: A multifaceted role for general regulatory factors.

    Science.gov (United States)

    Bosio, Maria Cristina; Fermi, Beatrice; Dieci, Giorgio

    2017-08-08

    In Saccharomyces cerevisiae, a group of more than 200 co-regulated genes (Ribi genes) is involved in ribosome biogenesis. This regulon has recently been shown to rely on a small set of transcriptional regulators (mainly Abf1, but also Reb1, Tbf1 and Rap1) previously referred to as general regulatory factors (GRFs) because of their widespread binding and action at many promoters and other specialized genomic regions. Intriguingly, Abf1 binding to Ribi genes is differentially modulated in response to distinct nutrition signaling pathways. Such a dynamic promoter association has the potential to orchestrate both activation and repression of Ribi genes in synergy with neighboring regulatory sites and through the functional interplay of histone acetyltransferases and deacetylases.

  6. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    OpenAIRE

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF...

  7. Sterol composition of virgin olive oil of forty-three olive cultivars from the World Collection Olive Germplasm Bank of Cordoba.

    Science.gov (United States)

    Kyçyk, Onejda; Aguilera, Maria Paz; Gaforio, José Juan; Jiménez, Antonio; Beltrán, Gabriel

    2016-09-01

    In olive oil, sterols constitute the majority of the unsaponifiable fraction. In recent years there has been increased interest in the sterols of olive oil for their health benefits and their importance to virgin olive oil (VOO) quality regulation. Forty-three olive (Olea europaea L.) cultivars from the World Olive Germplasm Bank, IFAPA Centro 'Alameda de Obispo', Cordoba, Spain were studied for their oil sterol composition and total content. The main sterols found in olive oil were β-sitosterol, Δ(5) -avenasterol, campesterol and stigmasterol, most of them showing high variability. Most cultivars showed total sterol contents within the limits established by EU regulations, although 28% of VOOs analysed were outside the limits established for total content and/or for individual sterols. Over the group of cultivars, total sterol contents ranged from 855 to 2185 mg kg(-1) . The high variability observed was due to the genetic component, since other agronomic and technological factors were similar. Because of the high variability, the sterol fraction can be considered as a useful tool to characterize and discriminate monovarietal VOOs. The results can be useful for nutritionists for VOO inclusion in nutrition studies. Furthermore, the variability observed can be applied in olive breeding projects to select the parents of new olive cultivars with an improved sterol fraction. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  8. Integration and diversity of the regulatory network composed of Maf and CNC families of transcription factors.

    Science.gov (United States)

    Motohashi, Hozumi; O'Connor, Tania; Katsuoka, Fumiki; Engel, James Douglas; Yamamoto, Masayuki

    2002-07-10

    Recent progress in the analysis of transcriptional regulation has revealed the presence of an exquisite functional network comprising the Maf and Cap 'n' collar (CNC) families of regulatory proteins, many of which have been isolated. Among Maf factors, large Maf proteins are important in the regulation of embryonic development and cell differentiation, whereas small Maf proteins serve as obligatory heterodimeric partner molecules for members of the CNC family. Both Maf homodimers and CNC-small Maf heterodimers bind to the Maf recognition element (MARE). Since the MARE contains a consensus TRE sequence recognized by AP-1, Jun and Fos family members may act to compete or interfere with the function of CNC-small Maf heterodimers. Overall then, the quantitative balance of transcription factors interacting with the MARE determines its transcriptional activity. Many putative MARE-dependent target genes such as those induced by antioxidants and oxidative stress are under concerted regulation by the CNC family member Nrf2, as clearly proven by mouse germline mutagenesis. Since these genes represent a vital aspect of the cellular defense mechanism against oxidative stress, Nrf2-null mutant mice are highly sensitive to xenobiotic and oxidative insults. Deciphering the molecular basis of the regulatory network composed of Maf and CNC families of transcription factors will undoubtedly lead to a new paradigm for the cooperative function of transcription factors.

  9. Sterol-dependent nuclear import of ORP1S promotes LXR regulated trans-activation of apoE

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungsoo, E-mail: sungsoo.lee@utsouthwestern.edu [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States); Wang, Ping-Yuan [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States); Jeong, Yangsik; Mangelsdorf, David J. [Departments of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041 (United States); Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041 (United States); Anderson, Richard G.W. [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States); Michaely, Peter, E-mail: peter.michaely@utsouthwestern.edu [Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039 (United States)

    2012-10-01

    Oxysterol binding protein related protein 1S (ORP1S) is a member of a family of sterol transport proteins. Here we present evidence that ORP1S translocates from the cytoplasm to the nucleus in response to sterol binding. The sterols that best promote nuclear import of ORP1S also activate the liver X receptor (LXR) transcription factors and we show that ORP1S binds to LXRs, promotes binding of LXRs to LXR response elements (LXREs) and specifically enhances LXR-dependent transcription via the ME.1 and ME.2 enhancer elements of the apoE gene. We propose that ORP1S is a cytoplasmic sterol sensor, which transports sterols to the nucleus and promotes LXR-dependent gene transcription through select enhancer elements. -- Highlights: Black-Right-Pointing-Pointer ORP1S translocates to the nucleus in response to sterol binding. Black-Right-Pointing-Pointer The sterols that best promote nuclear import of ORP1S are LXR agonists. Black-Right-Pointing-Pointer ORP1S binds to LXRs, enhances binding of LXRs to LXREs and promotes LXR-dependent transcription of apoE.

  10. Quantitative and qualitative analysis of sterols/sterolins and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-03

    Jun 3, 2008 ... Quantitative and qualitative analysis of sterols/sterolins ... method was developed to identify and quantify sterols (especially β-sitosterol) in chloroform extracts of ... Studies with phytosterols, especially β-sitosterol, have.

  11. Lovastatin insensitive 1, a Novel pentatricopeptide repeat protein, is a potential regulatory factor of isoprenoid biosynthesis in Arabidopsis.

    Science.gov (United States)

    Kobayashi, Keiko; Suzuki, Masashi; Tang, Jianwei; Nagata, Noriko; Ohyama, Kiyoshi; Seki, Hikaru; Kiuchi, Reiko; Kaneko, Yasuko; Nakazawa, Miki; Matsui, Minami; Matsumoto, Shogo; Yoshida, Shigeo; Muranaka, Toshiya

    2007-02-01

    Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidal non-mevalonate (MEP) pathway. Despite the compartmentalization of these two pathways, metabolic flow occurs between them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cross-talk. To identify such regulatory mechanisms, we isolated and characterized the Arabidopsis T-DNA insertion mutant lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, inhibitors of the MVA and MEP pathways, respectively. The accumulation of the major products of these pathways, i.e. sterols and chlorophyll, was less affected by lovastatin and clomazone, respectively, in loi1 than in the wild type. Furthermore, the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity analysis showed higher activity of HMGR in loi1-1 treated with lovastatin than that in the WT. We consider that the lovastatin-resistant phenotype of loi1-1 was derived from this post-transcriptional up-regulation of HMGR. The LOI1 gene encodes a novel pentatricopeptide repeat (PPR) protein. PPR proteins are thought to regulate the expression of genes encoded in organelle genomes by post-transcriptional regulation in mitochondria or plastids. Our results demonstrate that LOI1 is predicted to localize in mitochondria and has the ability to bind single-stranded nucleic acids. Our investigation revealed that the post-transcriptional regulation of mitochondrial RNA may be involved in isoprenoid biosynthesis in both the MVA and MEP pathways.

  12. Interplay of mitochondria apoptosis regulatory factors and microRNAs in valvular heart disease.

    Science.gov (United States)

    Jan, Muhammad Ishtiaq; Khan, Riaz Anwar; Ali, Tahir; Bilal, Muhammad; Bo, Long; Sajid, Abdul; Malik, Abdul; Urehman, Naseeb; Waseem, Nayyar; Nawab, Javed; Ali, Murad; Majeed, Abdul; Ahmad, Hamid; Aslam, Sohail; Hamera, Sadia; Sultan, Aneesa; Anees, Mariam; Javed, Qamar; Murtaza, Iram

    2017-09-06

    Valvular heart disease (VHD) is an active process involving a wide range of pathological changes. The major complications of VHD are stenosis and regurgitation, which are macroscopic phenomena, induced in part through cellular changes. Altered expression of mitochondria associated genes causes membrane potential depolarization, leading to the increased levels of apoptosis observed in cardiac dysfunction. Objective of this study is to find molecular medicine candidates that can control expression of the key mitochondria apoptosis regulatory genes. Present study aims to assess the way microRNA are involved in regulating mitochondrial apoptosis regulatory genes and observation of their expression in the heart valve dysfunction. Apoptotic genes PUMA and DRP1 were found to be highly expressed, whereas anti-apoptotic gene ARC was down regulated. The expression level of GATA-4 transcription factor was also reduced in cardiac valve tissues. MicroRNAs miR-15a and miR-29a were repressed, while miR-214 was up regulated. Furthermore, study showed that PUMA, DRP1 and ARC expression might be attenuated by their respective miRNAs. Our results indicate that mitochondria regulatory genes might be controlled by miR-15a, miR-29a and miR-214, in VHD patients. Present study may provide platform for future research regarding potential therapeutic role of miRNAs in CVDs. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Enzyme mechanisms for sterol C-methylations.

    Science.gov (United States)

    Nes, W David

    2003-09-01

    The mechanisms by which sterol methyl transferases (SMT) transform olefins into structurally different C-methylated products are complex, prompting over 50 years of intense research. Recent enzymological studies, together with the latest discoveries in the fossil record, functional analyses and gene cloning, establish new insights into the enzymatic mechanisms of sterol C-methylation and form a basis for understanding regulation and evolution of the sterol pathway. These studies suggest that SMTs, originated shortly after life appeared on planet earth. SMTs, including those which ultimately give rise to 24 alpha- and 24 beta-alkyl sterols, align the si(beta)-face pi-electrons of the Delta(24)-double bond with the S-methyl group of AdoMet relative to a set of deprotonation bases in the active site. From the orientation of the conformationally flexible side chain in the SMT Michaelis complex, it has been found that either a single product is formed or cationic intermediates are partitioned into multiple olefins. The product structure and stereochemistry of SMT action is phylogenetically distinct and physiologically significant. SMTs control phytosterol homeostasis and their activity is subject to feedback regulation by specific sterol inserts in the membrane. A unified conceptual framework has been formulated in the steric-electric plug model that posits SMT substrate acceptability on the generation of single or double 24-alkylated side chains, which is the basis for binding order, stereospecificity and product diversity in this class of AdoMet-dependent methyl transferase enzymes. The focus of this review is the mechanism of the C-methylation process which, as discussed, can be altered by point mutations in the enzyme to direct the shape of sterol structure to optimize function.

  14. Increments and duplication events of enzymes and transcription factors influence metabolic and regulatory diversity in prokaryotes.

    Directory of Open Access Journals (Sweden)

    Mario Alberto Martínez-Núñez

    Full Text Available In this work, the content of enzymes and DNA-binding transcription factors (TFs in 794 non-redundant prokaryotic genomes was evaluated. The identification of enzymes was based on annotations deposited in the KEGG database as well as in databases of functional domains (COG and PFAM and structural domains (Superfamily. For identifications of the TFs, hidden Markov profiles were constructed based on well-known transcriptional regulatory families. From these analyses, we obtained diverse and interesting results, such as the negative rate of incremental changes in the number of detected enzymes with respect to the genome size. On the contrary, for TFs the rate incremented as the complexity of genome increased. This inverse related performance shapes the diversity of metabolic and regulatory networks and impacts the availability of enzymes and TFs. Furthermore, the intersection of the derivatives between enzymes and TFs was identified at 9,659 genes, after this point, the regulatory complexity grows faster than metabolic complexity. In addition, TFs have a low number of duplications, in contrast to the apparent high number of duplications associated with enzymes. Despite the greater number of duplicated enzymes versus TFs, the increment by which duplicates appear is higher in TFs. A lower proportion of enzymes among archaeal genomes (22% than in the bacterial ones (27% was also found. This low proportion might be compensated by the interconnection between the metabolic pathways in Archaea. A similar proportion was also found for the archaeal TFs, for which the formation of regulatory complexes has been proposed. Finally, an enrichment of multifunctional enzymes in Bacteria, as a mechanism of ecological adaptation, was detected.

  15. Increments and duplication events of enzymes and transcription factors influence metabolic and regulatory diversity in prokaryotes.

    Science.gov (United States)

    Martínez-Núñez, Mario Alberto; Poot-Hernandez, Augusto Cesar; Rodríguez-Vázquez, Katya; Perez-Rueda, Ernesto

    2013-01-01

    In this work, the content of enzymes and DNA-binding transcription factors (TFs) in 794 non-redundant prokaryotic genomes was evaluated. The identification of enzymes was based on annotations deposited in the KEGG database as well as in databases of functional domains (COG and PFAM) and structural domains (Superfamily). For identifications of the TFs, hidden Markov profiles were constructed based on well-known transcriptional regulatory families. From these analyses, we obtained diverse and interesting results, such as the negative rate of incremental changes in the number of detected enzymes with respect to the genome size. On the contrary, for TFs the rate incremented as the complexity of genome increased. This inverse related performance shapes the diversity of metabolic and regulatory networks and impacts the availability of enzymes and TFs. Furthermore, the intersection of the derivatives between enzymes and TFs was identified at 9,659 genes, after this point, the regulatory complexity grows faster than metabolic complexity. In addition, TFs have a low number of duplications, in contrast to the apparent high number of duplications associated with enzymes. Despite the greater number of duplicated enzymes versus TFs, the increment by which duplicates appear is higher in TFs. A lower proportion of enzymes among archaeal genomes (22%) than in the bacterial ones (27%) was also found. This low proportion might be compensated by the interconnection between the metabolic pathways in Archaea. A similar proportion was also found for the archaeal TFs, for which the formation of regulatory complexes has been proposed. Finally, an enrichment of multifunctional enzymes in Bacteria, as a mechanism of ecological adaptation, was detected.

  16. Increments and Duplication Events of Enzymes and Transcription Factors Influence Metabolic and Regulatory Diversity in Prokaryotes

    Science.gov (United States)

    Martínez-Núñez, Mario Alberto; Poot-Hernandez, Augusto Cesar; Rodríguez-Vázquez, Katya; Perez-Rueda, Ernesto

    2013-01-01

    In this work, the content of enzymes and DNA-binding transcription factors (TFs) in 794 non-redundant prokaryotic genomes was evaluated. The identification of enzymes was based on annotations deposited in the KEGG database as well as in databases of functional domains (COG and PFAM) and structural domains (Superfamily). For identifications of the TFs, hidden Markov profiles were constructed based on well-known transcriptional regulatory families. From these analyses, we obtained diverse and interesting results, such as the negative rate of incremental changes in the number of detected enzymes with respect to the genome size. On the contrary, for TFs the rate incremented as the complexity of genome increased. This inverse related performance shapes the diversity of metabolic and regulatory networks and impacts the availability of enzymes and TFs. Furthermore, the intersection of the derivatives between enzymes and TFs was identified at 9,659 genes, after this point, the regulatory complexity grows faster than metabolic complexity. In addition, TFs have a low number of duplications, in contrast to the apparent high number of duplications associated with enzymes. Despite the greater number of duplicated enzymes versus TFs, the increment by which duplicates appear is higher in TFs. A lower proportion of enzymes among archaeal genomes (22%) than in the bacterial ones (27%) was also found. This low proportion might be compensated by the interconnection between the metabolic pathways in Archaea. A similar proportion was also found for the archaeal TFs, for which the formation of regulatory complexes has been proposed. Finally, an enrichment of multifunctional enzymes in Bacteria, as a mechanism of ecological adaptation, was detected. PMID:23922780

  17. Identification of High-Impact cis-Regulatory Mutations Using Transcription Factor Specific Random Forest Models.

    Directory of Open Access Journals (Sweden)

    Dmitry Svetlichnyy

    2015-11-01

    Full Text Available Cancer genomes contain vast amounts of somatic mutations, many of which are passenger mutations not involved in oncogenesis. Whereas driver mutations in protein-coding genes can be distinguished from passenger mutations based on their recurrence, non-coding mutations are usually not recurrent at the same position. Therefore, it is still unclear how to identify cis-regulatory driver mutations, particularly when chromatin data from the same patient is not available, thus relying only on sequence and expression information. Here we use machine-learning methods to predict functional regulatory regions using sequence information alone, and compare the predicted activity of the mutated region with the reference sequence. This way we define the Predicted Regulatory Impact of a Mutation in an Enhancer (PRIME. We find that the recently identified driver mutation in the TAL1 enhancer has a high PRIME score, representing a "gain-of-target" for MYB, whereas the highly recurrent TERT promoter mutation has a surprisingly low PRIME score. We trained Random Forest models for 45 cancer-related transcription factors, and used these to score variations in the HeLa genome and somatic mutations across more than five hundred cancer genomes. Each model predicts only a small fraction of non-coding mutations with a potential impact on the function of the encompassing regulatory region. Nevertheless, as these few candidate driver mutations are often linked to gains in chromatin activity and gene expression, they may contribute to the oncogenic program by altering the expression levels of specific oncogenes and tumor suppressor genes.

  18. Systematic Discovery of Archaeal Transcription Factor Functions in Regulatory Networks through Quantitative Phenotyping Analysis.

    Science.gov (United States)

    Darnell, Cynthia L; Tonner, Peter D; Gulli, Jordan G; Schmidler, Scott C; Schmid, Amy K

    2017-01-01

    Gene regulatory networks (GRNs) are critical for dynamic transcriptional responses to environmental stress. However, the mechanisms by which GRN regulation adjusts physiology to enable stress survival remain unclear. Here we investigate the functions of transcription factors (TFs) within the global GRN of the stress-tolerant archaeal microorganism Halobacterium salinarum. We measured growth phenotypes of a panel of TF deletion mutants in high temporal resolution under heat shock, oxidative stress, and low-salinity conditions. To quantitate the noncanonical functional forms of the growth trajectories observed for these mutants, we developed a novel modeling framework based on Gaussian process regression and functional analysis of variance (FANOVA). We employ unique statistical tests to determine the significance of differential growth relative to the growth of the control strain. This analysis recapitulated known TF functions, revealed novel functions, and identified surprising secondary functions for characterized TFs. Strikingly, we observed that the majority of the TFs studied were required for growth under multiple stress conditions, pinpointing regulatory connections between the conditions tested. Correlations between quantitative phenotype trajectories of mutants are predictive of TF-TF connections within the GRN. These phenotypes are strongly concordant with predictions from statistical GRN models inferred from gene expression data alone. With genome-wide and targeted data sets, we provide detailed functional validation of novel TFs required for extreme oxidative stress and heat shock survival. Together, results presented in this study suggest that many TFs function under multiple conditions, thereby revealing high interconnectivity within the GRN and identifying the specific TFs required for communication between networks responding to disparate stressors. IMPORTANCE To ensure survival in the face of stress, microorganisms employ inducible damage repair

  19. Biological removal of phyto-sterols in pulp mill effluents.

    Science.gov (United States)

    Mahmood-Khan, Zahid; Hall, Eric R

    2013-12-15

    Phyto-sterols and extractives found in pulp mill effluents are suspected to cause endocrine abnormalities in receiving water fish. The control of sterols in pulp mill effluents through biological secondary wastewater treatment was studied using two lab-scale bioreactor systems. After achieving a stable performance, both bioreactor systems successfully removed (>90%) sterols and the estimated biodegradation was up to 80%. Reactor 1 system operating at 6.7 ± 0.2 pH effectively treated pulp mill effluent sterols spiked up to 4500 μg/L in 11 h HRT and 11 day SRT. However, Reactor 2 system operating at 7.6 ± 0.2 pH performed relatively poorly. Retention time reductions beyond critical values deteriorated the performance of treatment systems and quickly reduced the sterols biodegradation. The biodegradation loss was indicated by mixed liquor sterols content that started increasing. This biodegradation loss was compensated by the increased role of bio-adsorption and the overall sterols removal remained relatively high. Hence, a relatively small (20-30%) loss in the overall sterols removal efficiency did not fully reflect the associated major (60-70%) loss in the sterols biodegradation because the amount of sterols accumulated in the sludge due to adsorption increased so the estimate of sterols removal through adsorption increased from 30-40% to 70-80% keeping the overall sterols removal still high.

  20. Deficiency in the Lipid Exporter ABCA1 Impairs Retrograde Sterol Movement and Disrupts Sterol Sensing at the Endoplasmic Reticulum.

    Science.gov (United States)

    Yamauchi, Yoshio; Iwamoto, Noriyuki; Rogers, Maximillian A; Abe-Dohmae, Sumiko; Fujimoto, Toyoshi; Chang, Catherine C Y; Ishigami, Masato; Kishimoto, Takuma; Kobayashi, Toshihide; Ueda, Kazumitsu; Furukawa, Koichi; Chang, Ta-Yuan; Yokoyama, Shinji

    2015-09-25

    Cellular cholesterol homeostasis involves sterol sensing at the endoplasmic reticulum (ER) and sterol export from the plasma membrane (PM). Sterol sensing at the ER requires efficient sterol delivery from the PM; however, the macromolecules that facilitate retrograde sterol transport at the PM have not been identified. ATP-binding cassette transporter A1 (ABCA1) mediates cholesterol and phospholipid export to apolipoprotein A-I for the assembly of high density lipoprotein (HDL). Mutations in ABCA1 cause Tangier disease, a familial HDL deficiency. Several lines of clinical and experimental evidence suggest a second function of ABCA1 in cellular cholesterol homeostasis in addition to mediating cholesterol efflux. Here, we report the unexpected finding that ABCA1 also plays a key role in facilitating retrograde sterol transport from the PM to the ER for sterol sensing. Deficiency in ABCA1 delays sterol esterification at the ER and activates the SREBP-2 cleavage pathway. The intrinsic ATPase activity in ABCA1 is required to facilitate retrograde sterol transport. ABCA1 deficiency causes alternation of PM composition and hampers a clathrin-independent endocytic activity that is required for ER sterol sensing. Our finding identifies ABCA1 as a key macromolecule facilitating bidirectional sterol movement at the PM and shows that ABCA1 controls retrograde sterol transport by modulating a certain clathrin-independent endocytic process.

  1. Skeletal muscle hypertrophy and regeneration: interplay between the myogenic regulatory factors (MRFs) and insulin-like growth factors (IGFs) pathways.

    Science.gov (United States)

    Zanou, Nadège; Gailly, Philippe

    2013-11-01

    Adult skeletal muscle can regenerate in response to muscle damage. This ability is conferred by the presence of myogenic stem cells called satellite cells. In response to stimuli such as injury or exercise, these cells become activated and express myogenic regulatory factors (MRFs), i.e., transcription factors of the myogenic lineage including Myf5, MyoD, myogenin, and Mrf4 to proliferate and differentiate into myofibers. The MRF family of proteins controls the transcription of important muscle-specific proteins such as myosin heavy chain and muscle creatine kinase. Different growth factors are secreted during muscle repair among which insulin-like growth factors (IGFs) are the only ones that promote both muscle cell proliferation and differentiation and that play a key role in muscle regeneration and hypertrophy. Different isoforms of IGFs are expressed during muscle repair: IGF-IEa, IGF-IEb, or IGF-IEc (also known as mechano growth factor, MGF) and IGF-II. MGF is expressed first and is observed in satellite cells and in proliferating myoblasts whereas IGF-Ia and IGF-II expression occurs at the state of muscle fiber formation. Interestingly, several studies report the induction of MRFs in response to IGFs stimulation. Inversely, IGFs expression may also be regulated by MRFs. Various mechanisms are proposed to support these interactions. In this review, we describe the general process of muscle hypertrophy and regeneration and decipher the interactions between the two groups of factors involved in the process.

  2. Two New Sterols from Bolbostemma paniculatum

    Institute of Scientific and Technical Information of China (English)

    Wen Yong LIU; Wei Dong ZHANG; Hai Sheng CHEN; Zheng Bing GU; Ting Zhao LI; Wan Sheng CHEN

    2003-01-01

    Two new sterols were isolated from bulbs of Bolbostemma paniculatum (Maxim.)Franquet. Their structures were elucidated as stigmasta-7, 22, 25-triene-3-O-nonadecanoic acidester (1) and stigmasta-7, 22, 25-triene-3-O-β-D- (6'-palmitoyl) glucopyranoside (2) by chemicaland spectroscopic methods.

  3. Sterol composition of shellfish species commonly consumed in the United States

    Directory of Open Access Journals (Sweden)

    Katherine M. Phillips

    2012-10-01

    and quantitation of sterols in marine species more complex than in animal and plant tissues. The detailed sterol composition reported herein provides data that may be useful in research on the impact of shellfish consumption on dietary risk factors.

  4. Effect of plant sterols on the lipid profile of patients with hypercholesterolaemia. Randomised, experimental study

    Directory of Open Access Journals (Sweden)

    Lloret Ángeles

    2011-09-01

    Full Text Available Abstract Background Studies have been conducted on supplementing the daily diet with plant sterol ester-enriched milk derivatives in order to reduce LDL-cholesterol levels and, consequently, cardiovascular risk. However, clinical practice guidelines on hypercholesterolaemia state that there is not sufficient evidence to recommend their use in subjects with hypercholesterolaemia. The main objective of this study is to determine the efficacy of the intake of 2 g of plant sterol esters a day in lowering LDL-cholesterol levels in patients diagnosed with hypercholesterolaemia. The specific objectives are: 1 to quantify the efficacy of the daily intake of plant sterol esters in lowering LDL-cholesterol, total cholesterol and cardiovascular risk in patients with hypercholesterolaemia; 2 to evaluate the occurrence of adverse effects of the daily intake of plant sterol esters; 3 to identify the factors that determine a greater reduction in lipid levels in subjects receiving plant sterol ester supplements. Methods/Design Randomised, double-blind, placebo controlled experimental trial carried out at family doctors' surgeries at three health centres in the Health Area of Albacete (Spain. The study subjects will be adults diagnosed with "limit" or "defined" hypercholesterolaemia and who have LDL cholesterol levels of 130 mg/dl or over. A dairy product in the form of liquid yoghurt containing 2 g of plant sterol ester per container will be administered daily after the main meal, for a period of 24 months. The control group will receive a daily unit of yogurt not supplemented with plant sterol esters that has a similar appearance to the enriched yoghurt. The primary variable is the change in lipid profile at 1, 3, 6, 12, 18 and 24 months. The secondary variables are: change in cardiovascular risk, adherence to the dairy product, adverse effects, adherence to dietary recommendations, frequency of food consumption, basic physical examination data, health

  5. Effect of plant sterols on the lipid profile of patients with hypercholesterolaemia. Randomised, experimental study.

    Science.gov (United States)

    Párraga, Ignacio; López-Torres, Jesús; Andrés, Fernando; Navarro, Beatriz; del Campo, José M; García-Reyes, Mercedes; Galdón, María P; Lloret, Angeles; Precioso, Juan C; Rabanales, Joseba

    2011-09-12

    Studies have been conducted on supplementing the daily diet with plant sterol ester-enriched milk derivatives in order to reduce LDL-cholesterol levels and, consequently, cardiovascular risk. However, clinical practice guidelines on hypercholesterolaemia state that there is not sufficient evidence to recommend their use in subjects with hypercholesterolaemia. The main objective of this study is to determine the efficacy of the intake of 2 g of plant sterol esters a day in lowering LDL-cholesterol levels in patients diagnosed with hypercholesterolaemia. The specific objectives are: 1) to quantify the efficacy of the daily intake of plant sterol esters in lowering LDL-cholesterol, total cholesterol and cardiovascular risk in patients with hypercholesterolaemia; 2) to evaluate the occurrence of adverse effects of the daily intake of plant sterol esters; 3) to identify the factors that determine a greater reduction in lipid levels in subjects receiving plant sterol ester supplements. Randomised, double-blind, placebo controlled experimental trial carried out at family doctors' surgeries at three health centres in the Health Area of Albacete (Spain). The study subjects will be adults diagnosed with "limit" or "defined" hypercholesterolaemia and who have LDL cholesterol levels of 130 mg/dl or over. A dairy product in the form of liquid yoghurt containing 2 g of plant sterol ester per container will be administered daily after the main meal, for a period of 24 months. The control group will receive a daily unit of yogurt not supplemented with plant sterol esters that has a similar appearance to the enriched yoghurt. The primary variable is the change in lipid profile at 1, 3, 6, 12, 18 and 24 months. The secondary variables are: change in cardiovascular risk, adherence to the dairy product, adverse effects, adherence to dietary recommendations, frequency of food consumption, basic physical examination data, health problems, lipid-lowering medication, physical activity

  6. Plant Sterols as Anticancer Nutrients: Evidence for Their Role in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Bruce J. Grattan

    2013-01-01

    Full Text Available While many factors are involved in the etiology of cancer, it has been clearly established that diet significantly impacts one’s risk for this disease. More recently, specific food components have been identified which are uniquely beneficial in mitigating the risk of specific cancer subtypes. Plant sterols are well known for their effects on blood cholesterol levels, however research into their potential role in mitigating cancer risk remains in its infancy. As outlined in this review, the cholesterol modulating actions of plant sterols may overlap with their anti-cancer actions. Breast cancer is the most common malignancy affecting women and there remains a need for effective adjuvant therapies for this disease, for which plant sterols may play a distinctive role.

  7. Interferon regulatory factor 5 gene polymorphism in Egyptian children with systemic lupus erythematosus.

    Science.gov (United States)

    Hammad, A; Mossad, Y M; Nasef, N; Eid, R

    2017-01-01

    Background Increased expression of interferon-inducible genes is implicated in the pathogenesis of systemic lupus erythematosus (SLE). Interferon regulatory factor 5 (IRF5) is one of the transcription factors regulating interferon and was proved to be implicated in the pathogenesis of SLE in different populations. Objectives The objective of this study was to investigate the correlation between polymorphisms of the IRF5 gene and SLE susceptibility in a cohort of Egyptian children and to investigate their association with clinico-pathological features, especially lupus nephritis. Subjects and methods Typing of interferon regulatory factor 5 rs10954213, rs2004640 and rs2280714 polymorphisms were done using polymerase chain reaction-restriction fragment length polymorphism for 100 children with SLE and 100 matched healthy controls. Results Children with SLE had more frequent T allele and TT genotype of rs2004640 ( Pc = 0.003 and 0.024, respectively) compared to controls. Patients with nephritis had more frequent T allele of rs2004640 compared to controls ( Pc = 0.003). However the allele and genotype frequencies of the three studied polymorphisms did not show any difference in patients with nephritis in comparison to those without nephritis. Haplotype GTA of rs10954213, rs2004640 and rs2280714, respectively, was more frequent in lupus patients in comparison to controls ( p = 0.01) while the haplotype GGG was more frequent in controls than lupus patients ( p = 0.011). Conclusion The rs2004640 T allele and TT genotype and GTA haplotype of rs rs10954213, rs2004640, and rs2280714, respectively, can be considered as risk factors for the development of SLE. The presence of the rs2004640 T allele increases the risk of nephritis development in Egyptian children with SLE.

  8. A consensus network of gene regulatory factors in the human frontal lobe

    Directory of Open Access Journals (Sweden)

    Stefano eBerto

    2016-03-01

    Full Text Available Cognitive abilities, such as memory, learning, language, problem solving, and planning, involve the frontal lobe and other brain areas. Not much is known yet about the molecular basis of cognitive abilities, but it seems clear that cognitive abilities are determined by the interplay of many genes. One approach for analyzing the genetic networks involved in cognitive functions is to study the coexpression networks of genes with known importance for proper cognitive functions, such as genes that have been associated with cognitive disorders like intellectual disability (ID or autism spectrum disorders (ASD. Because many of these genes are gene regulatory factors (GRFs we aimed to provide insights into the gene regulatory networks active in the human frontal lobe. Using genome wide human frontal lobe expression data from 10 independent data sets, we first derived 10 individual coexpression networks for all GRFs including their potential target genes. We observed a high level of variability among these 10 independently derived networks, pointing out that relying on results from a single study can only provide limited biological insights. To instead focus on the most confident information from these 10 networks we developed a method for integrating such independently derived networks into a consensus network. This consensus network revealed robust GRF interactions that are conserved across the frontal lobes of different healthy human individuals. Within this network, we detected a strong central module that is enriched for 166 GRFs known to be involved in brain development and/or cognitive disorders. Interestingly, several hubs of the consensus network encode for GRFs that have not yet been associated with brain functions. Their central role in the network suggests them as excellent new candidates for playing an essential role in the regulatory network of the human frontal lobe, which should be investigated in future studies.

  9. A Consensus Network of Gene Regulatory Factors in the Human Frontal Lobe.

    Science.gov (United States)

    Berto, Stefano; Perdomo-Sabogal, Alvaro; Gerighausen, Daniel; Qin, Jing; Nowick, Katja

    2016-01-01

    Cognitive abilities, such as memory, learning, language, problem solving, and planning, involve the frontal lobe and other brain areas. Not much is known yet about the molecular basis of cognitive abilities, but it seems clear that cognitive abilities are determined by the interplay of many genes. One approach for analyzing the genetic networks involved in cognitive functions is to study the coexpression networks of genes with known importance for proper cognitive functions, such as genes that have been associated with cognitive disorders like intellectual disability (ID) or autism spectrum disorders (ASD). Because many of these genes are gene regulatory factors (GRFs) we aimed to provide insights into the gene regulatory networks active in the human frontal lobe. Using genome wide human frontal lobe expression data from 10 independent data sets, we first derived 10 individual coexpression networks for all GRFs including their potential target genes. We observed a high level of variability among these 10 independently derived networks, pointing out that relying on results from a single study can only provide limited biological insights. To instead focus on the most confident information from these 10 networks we developed a method for integrating such independently derived networks into a consensus network. This consensus network revealed robust GRF interactions that are conserved across the frontal lobes of different healthy human individuals. Within this network, we detected a strong central module that is enriched for 166 GRFs known to be involved in brain development and/or cognitive disorders. Interestingly, several hubs of the consensus network encode for GRFs that have not yet been associated with brain functions. Their central role in the network suggests them as excellent new candidates for playing an essential role in the regulatory network of the human frontal lobe, which should be investigated in future studies.

  10. Factors influencing quality decision-making: regulatory and pharmaceutical industry perspectives.

    Science.gov (United States)

    Donelan, Ronan; Walker, Stuart; Salek, Sam

    2015-03-01

    Currently, there is no qualified understanding of the influences, behaviours and other factors that impact the decision-making of individuals and organisations involved in the development of new medicines. The aim of this qualitative study was to investigate and identify the important issues that influence quality decision-making. Semi-structured interviews were carried out with 29 senior decision-makers from the pharmaceutical industry and regulatory authorities. The study participants were invited to discuss and review their perception of decision-making within their organisation, its role in drug development and the regulatory review and their awareness and use of decision-making techniques and the impact and monitoring of decisions. The analyses (using NVivo 8(©) software) resulted in the identification of 32 major and 97 sub-themes that were consolidated into 19 overarching themes. These included items such as quality and validity of data, time considerations, organisational and cultural influences, analytical and logical approach, qualification and experience, subjective and personal considerations, political influences, precedents for similar previous decisions, understanding of the decision in question, impact analyses, audit trail, education and awareness, individual versus corporate decision-making and frameworks. Relationships between themes were identified. The 19 overarching decision-making themes were integrated into a framework for quality decision-making. This study has achieved its aim of exploring decision-making from the perspective of the individual and the organisation working in drug development and the regulatory review and has identified issues and considerations relating to making good quality decisions and allowed for the generation of a framework to aid quality decision-making. Copyright © 2015 John Wiley & Sons, Ltd.

  11. Targeted inactivation of Snail family EMT regulatory factors by a Co(III)-Ebox conjugate.

    Science.gov (United States)

    Harney, Allison S; Meade, Thomas J; LaBonne, Carole

    2012-01-01

    Snail family proteins are core EMT (epithelial-mesenchymal transition) regulatory factors that play essential roles in both development and disease processes and have been associated with metastasis in carcinomas. Snail factors are required for the formation of neural crest stem cells in most vertebrate embryos, as well as for the migratory invasive behavior of these cells. Snail factors have recently been linked to the formation of cancer stem cells, and expression of Snail proteins may be associated with tumor recurrence and resistance to chemotherapy and radiotherapy. We report that Co(III)-Ebox is a potent inhibitor of Snail-mediated transcriptional repression in breast cancer cells and in the neural crest of Xenopus. We further show that the activity of Co(III)-Ebox can be modulated by temperature, increasing the utility of this conjugate as a Snail inhibitor in model organisms. We exploit this feature to further delineate the requirements for Snail function during neural crest development, showing that in addition to the roles that Snail factors play in neural crest precursor formation and neural crest EMT/migration, inhibition of Snail function after the onset of neural crest migration leads to a loss of neural crest derived melanocytes. Co(III)-Ebox-mediated inhibition therefore provides a powerful tool for analysing the function of these core EMT factors with unparalleled temporal resolution. Moreover, the potency of Co(III)-Ebox as a Snail inhibitor in breast cancer cells suggests its potential as a therapeutic inhibitor of tumor progression and metastasis.

  12. Chromatin properties of regulatory DNA probed by manipulation of transcription factors.

    Science.gov (United States)

    Sharov, Alexei A; Nishiyama, Akira; Qian, Yong; Dudekula, Dawood B; Longo, Dan L; Schlessinger, David; Ko, Minoru S H

    2014-08-01

    Transcription factors (TFs) bind to DNA and regulate the transcription of nearby genes. However, only a small fraction of TF binding sites have such regulatory effects. Here we search for the predictors of functional binding sites by carrying out a systematic computational screening of a variety of contextual factors (histone modifications, nuclear lamin-bindings, and cofactor bindings). We used regression analysis to test if contextual factors are associated with upregulation or downregulation of neighboring genes following the induction or knockdown of the 9 TFs in mouse embryonic stem (ES) cells. Functional TF binding sites appeared to be either active (i.e., bound by P300, CHD7, mediator, cohesin, and SWI/SNF) or repressed (i.e., with H3K27me3 histone marks and bound by Polycomb factors). Active binding sites mediated the downregulation of nearby genes upon knocking down the activating TFs or inducing repressors. Repressed TF binding sites mediated the upregulation of nearby genes (e.g., poised developmental regulators) upon inducing TFs. In addition, repressed binding sites mediated repressive effects of TFs, identified by the downregulation of target genes after the induction of TFs or by the upregulation of target genes after the knockdown of TFs. The contextual factors associated with functions of DNA-bound TFs were used to improve the identification of candidate target genes regulated by TFs.

  13. Chromatin Properties of Regulatory DNA Probed by Manipulation of Transcription Factors

    Science.gov (United States)

    Sharov, Alexei A.; Nishiyama, Akira; Qian, Yong; Dudekula, Dawood B.; Longo, Dan L.; Schlessinger, David

    2014-01-01

    Abstract Transcription factors (TFs) bind to DNA and regulate the transcription of nearby genes. However, only a small fraction of TF binding sites have such regulatory effects. Here we search for the predictors of functional binding sites by carrying out a systematic computational screening of a variety of contextual factors (histone modifications, nuclear lamin-bindings, and cofactor bindings). We used regression analysis to test if contextual factors are associated with upregulation or downregulation of neighboring genes following the induction or knockdown of the 9 TFs in mouse embryonic stem (ES) cells. Functional TF binding sites appeared to be either active (i.e., bound by P300, CHD7, mediator, cohesin, and SWI/SNF) or repressed (i.e., with H3K27me3 histone marks and bound by Polycomb factors). Active binding sites mediated the downregulation of nearby genes upon knocking down the activating TFs or inducing repressors. Repressed TF binding sites mediated the upregulation of nearby genes (e.g., poised developmental regulators) upon inducing TFs. In addition, repressed binding sites mediated repressive effects of TFs, identified by the downregulation of target genes after the induction of TFs or by the upregulation of target genes after the knockdown of TFs. The contextual factors associated with functions of DNA-bound TFs were used to improve the identification of candidate target genes regulated by TFs. PMID:24918633

  14. The Ets-1 transcription factor controls the development and function of natural regulatory T cells

    Science.gov (United States)

    Mouly, Enguerran; Chemin, Karine; Nguyen, Hai Vu; Chopin, Martine; Mesnard, Laurent; Leite-de-Moraes, Maria; Burlen-defranoux, Odile; Bandeira, Antonio

    2010-01-01

    Regulatory T cells (T reg cells) constitute a population of CD4+ T cells that limits immune responses. The transcription factor Foxp3 is important for determining the development and function of T reg cells; however, the molecular mechanisms that trigger and maintain its expression remain incompletely understood. In this study, we show that mice deficient for the Ets-1 transcription factor (Ets-1−/−) developed T cell–mediated splenomegaly and systemic autoimmunity that can be blocked by functional wild-type T reg cells. Spleens of Ets-1−/− mice contained mostly activated T cells, including Th2-polarized CD4+ cells and had reduced percentages of T reg cells. Splenic and thymic Ets-1−/− T reg cells expressed low levels of Foxp3 and displayed the CD103 marker that characterizes antigen-experienced T reg cells. Thymic development of Ets-1−/− T reg cells appeared intrinsically altered as Foxp3-expressing cells differentiate poorly in mixed fetal liver reconstituted chimera and fetal thymic organ culture. Ets-1−/− T reg cells showed decreased in vitro suppression activity and did not protect Rag2−/− hosts from naive T cell–induced inflammatory bowel disease. Furthermore, in T reg cells, Ets-1 interacted with the Foxp3 intronic enhancer and was required for demethylation of this regulatory sequence. These data demonstrate that Ets-1 is required for the development of natural T reg cells and suggest a role for this transcription factor in the regulation of Foxp3 expression. PMID:20855499

  15. Medusa structure of the gene regulatory network: dominance of transcription factors in cancer subtype classification.

    Science.gov (United States)

    Guo, Yuchun; Feng, Ying; Trivedi, Niraj S; Huang, Sui

    2011-05-01

    Gene expression profiles consisting of ten thousands of transcripts are used for clustering of tissue, such as tumors, into subtypes, often without considering the underlying reason that the distinct patterns of expression arise because of constraints in the realization of gene expression profiles imposed by the gene regulatory network. The topology of this network has been suggested to consist of a regulatory core of genes represented most prominently by transcription factors (TFs) and microRNAs, that influence the expression of other genes, and of a periphery of 'enslaved' effector genes that are regulated but not regulating. This 'medusa' architecture implies that the core genes are much stronger determinants of the realized gene expression profiles. To test this hypothesis, we examined the clustering of gene expression profiles into known tumor types to quantitatively demonstrate that TFs, and even more pronounced, microRNAs, are much stronger discriminators of tumor type specific gene expression patterns than a same number of randomly selected or metabolic genes. These findings lend support to the hypothesis of a medusa architecture and of the canalizing nature of regulation by microRNAs. They also reveal the degree of freedom for the expression of peripheral genes that are less stringently associated with a tissue type specific global gene expression profile.

  16. Engineering Synthetic cis-Regulatory Elements for Simultaneous Recognition of Three Transcriptional Factors in Bacteria.

    Science.gov (United States)

    Amores, Gerardo Ruiz; Guazzaroni, María-Eugenia; Silva-Rocha, Rafael

    2015-12-18

    Recognition of cis-regulatory elements by transcription factors (TF) at target promoters is crucial to gene regulation in bacteria. In this process, binding of TFs to their cognate sequences depends on a set of physical interactions between these proteins and specific nucleotides in the operator region. Previously, we showed that in silico optimization algorithms are able to generate short sequences that are recognized by two different TFs of Escherichia coli, namely, CRP and IHF, thus generating an AND logic gate. Here, we expanded this approach in order to engineer DNA sequences that can be simultaneously recognized by three unrelated TFs (CRP, IHF, and Fis). Using in silico optimization and experimental validation strategies, we were able to obtain a candidate promoter (Plac-CFI1) regulated by only two TFs with an AND logic, thus demonstrating a limitation in the design. Subsequently, we modified the algorithm to allow the optimization of extended sequences, and were able to design two synthetic promoters (PCFI20-1 and PCFI22-5) that were functional in vivo. Expression assays in E. coli mutant strains for each TF revealed that while CRP positively regulates the promoter activities, IHF and Fis are strong repressors of both the promoter variants. Taken together, our results demonstrate the potential of in silico strategies in bacterial synthetic promoter engineering. Furthermore, the study also shows how small modifications in cis-regulatory elements can drastically affect the final logic of the resulting promoter.

  17. Brain-derived neurotrophic factor enhances calcium regulatory mechanisms in human airway smooth muscle.

    Directory of Open Access Journals (Sweden)

    Amard J Abcejo

    Full Text Available Neurotrophins (NTs, which play an integral role in neuronal development and function, have been found in non-neuronal tissue (including lung, but their role is still under investigation. Recent reports show that NTs such as brain-derived neurotrophic factor (BDNF as well as NT receptors are expressed in human airway smooth muscle (ASM. However, their function is still under investigation. We hypothesized that NTs regulate ASM intracellular Ca(2+ ([Ca(2+](i by altered expression of Ca(2+ regulatory proteins. Human ASM cells isolated from lung samples incidental to patient surgery were incubated for 24 h (overnight in medium (control or 1 nM BDNF in the presence vs. absence of inhibitors of signaling cascades (MAP kinases; PI3/Akt; NFκB. Measurement of [Ca(2+](i responses to acetylcholine (ACh and histamine using the Ca(2+ indicator fluo-4 showed significantly greater responses following BDNF exposure: effects that were blunted by pathway inhibitors. Western analysis of whole cell lysates showed significantly higher expression of CD38, Orai1, STIM1, IP(3 and RyR receptors, and SERCA following BDNF exposure, effects inhibited by inhibitors of the above cascades. The functional significance of BDNF effects were verified by siRNA or pharmacological inhibition of proteins that were altered by this NT. Overall, these data demonstrate that NTs activate signaling pathways in human ASM that lead to enhanced [Ca(2+](i responses via increased regulatory protein expression, thus enhancing airway contractility.

  18. Transcription profile of Escherichia coli: genomic SELEX search for regulatory targets of transcription factors.

    Science.gov (United States)

    Ishihama, Akira; Shimada, Tomohiro; Yamazaki, Yukiko

    2016-03-18

    Bacterial genomes are transcribed by DNA-dependent RNA polymerase (RNAP), which achieves gene selectivity through interaction with sigma factors that recognize promoters, and transcription factors (TFs) that control the activity and specificity of RNAP holoenzyme. To understand the molecular mechanisms of transcriptional regulation, the identification of regulatory targets is needed for all these factors. We then performed genomic SELEX screenings of targets under the control of each sigma factor and each TF. Here we describe the assembly of 156 SELEX patterns of a total of 116 TFs performed in the presence and absence of effector ligands. The results reveal several novel concepts: (i) each TF regulates more targets than hitherto recognized; (ii) each promoter is regulated by more TFs than hitherto recognized; and (iii) the binding sites of some TFs are located within operons and even inside open reading frames. The binding sites of a set of global regulators, including cAMP receptor protein, LeuO and Lrp, overlap with those of the silencer H-NS, suggesting that certain global regulators play an anti-silencing role. To facilitate sharing of these accumulated SELEX datasets with the research community, we compiled a database, 'Transcription Profile of Escherichia coli' (www.shigen.nig.ac.jp/ecoli/tec/). © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Hepatic expression of sterol regulatory element binding protein 1c and its significance in patients with non-alcoholic fatty liver disease%非酒精性脂肪肝患者肝脏固醇调节元件结合蛋白1c的表达及意义

    Institute of Scientific and Technical Information of China (English)

    孙振江; 石伟珍; 王宇芳; 施军平; 过建春

    2014-01-01

    Objective To investigate the hepatic expression of sterol regulatory element binding protein (SREBP)-1c in patients with non-alcoholic fatty liver disease (NAFLD) and its significance.Methods Twenty patients with NAFLD were included,and 20 age/sex matched asymptomatic HBV carriers (ASC) without steatosis evidenced by liver biopsy were used as control in the same time scale.Hepatic SREBP1c was detected using SP method of immunohistochemistry.An automatic biochemical analyzer (Hitachi 7060) was used to measure serum levels of lipids (TG,CHO),fasting blood glucose (FBG) and liver enzymes (AST,A LT,and GGT),and electrochemiluminescence was used to determine fasting insulin (FINS).Results Compared with the control group,NAFLD patients showed diffusely hepatic steatosis and a significantly higher expression of hepatic SREBP1c (P < 0.05).Consistently,serum levels of ALT,AST,TG,CHO,FSG and FINS all increased than those of control group (P < 0.05).Conclusions Hepatic expression of SREBP1c increased significantly in patients with NAFLD,and this over expression may be involve in fatty degeneration of the livers in human.%目的 观察非酒精性脂肪性肝病(NAFLD)患者肝组织固醇调节元件结合蛋白(SREBP1c)的表达变化,探讨其在NAFLD病理变化形成中的作用.方法 研究对象为NAFLD患者20例,20例年龄性别匹配的同期住院行肝活检无活动肝病组织学证据且肝脂肪变<5%的慢性HBV携带者(ASC)设为对照组.免疫组织化学染色检测两组患者肝组织SREBP1c的表达,并比较血脂(TG、CHO)、空腹血糖(FBG)、空腹胰岛素(FINS)和血清肝脏酶谱(AST、ALT、GGT)等的组间差异.结果 与对照组患者比较,NAFLD组肝组织呈不同程度的弥漫性肝细胞脂肪变性,肝组织SREBP1c表达明显升高(P<0.05),与此一致,血清ALT、AST、TG、CHO、FBG、FINS水平升高(P均<0.05).结论 NAFLD患者肝组织SREBP1 c表达增高,在人NAFLD脂肪变形成过程中起重要作用.

  20. Regulatory Network of Transcription Factors in Response to Drought in Arabidopsis and Crops

    Institute of Scientific and Technical Information of China (English)

    Chen Li-miao; Li Wen-bin; Zhou Xin-an

    2012-01-01

    Drought is one of the most important environmental constraints limiting plant growth, development and crop yield. Many drought-inducible genes have been identified by molecular and genomic analyses in Arabidopsis, rice and other crops. To better understand reaction mechanism of plant to drought tolerance, we mainly focused on introducing the research of transcription factors (TFs) in signal transduction and regulatory network of gene expression conferring drought. A TF could bind multiple target genes to increase one or more kinds of stress tolerance. Sometimes, several TFs might act together with a target gene. So drought-tolerance genes or TFs might respond to high-salinity, cold or other stresses. The crosstalk of multiple stresses signal pathways is a crucial aspect of understanding stress signaling.

  1. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression.

    Science.gov (United States)

    Wei, Zhiquan; Yan, Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-08-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interferon regulatory factor 5 (IRF5) has been identified as a key regulatory factor for macrophage classical activation. The present study used the THP‑1 human monocyte cell line to investigate whether mangiferin inhibits macrophage classical activation via suppressing IRF5 expression in vitro. THP‑1 cells were differentiated to macrophages by phorbol 12‑myristate 13‑acetate. Macrophages were polarized to M1 macrophages following stimulation with lipopolysaccharide (LPS)/interferon‑γ (IFN‑γ). Flow cytometric analysis was conducted to detect the M1 macrophages. Reverse transcription‑quantitative polymerase chain reaction was used to investigate cellular IRF5 gene expression. Levels of proinflammatory cytokines and IRF5 were assessed following cell culture and cellular homogenization using enzyme‑linked immunosorbent assay. IRF5 protein and nuclei co‑localization was performed in macrophages with laser scanning confocal microscope immunofluorescence analysis. The results of the present study demonstrated that mangiferin significantly inhibits LPS/IFN‑γ stimulation‑induced classical activation of macrophages in vitro and markedly decreases proinflammatory cytokine release. In addition, cellular IRF5 expression was markedly downregulated. These results suggest that the inhibitory effect of mangiferin on classical activation of macrophages may be exerted via downregulation of cellular IRF5 expression levels.

  2. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression

    Science.gov (United States)

    Wei, Zhiquan; Yan, Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-01-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interferon regulatory factor 5 (IRF5) has been identified as a key regulatory factor for macrophage classical activation. The present study used the THP-1 human monocyte cell line to investigate whether mangiferin inhibits macrophage classical activation via suppressing IRF5 expression in vitro. THP-1 cells were differentiated to macrophages by phorbol 12-myristate 13-acetate. Macrophages were polarized to M1 macrophages following stimulation with lipopolysaccharide (LPS)/interferon-γ (IFN-γ). Flow cytometric analysis was conducted to detect the M1 macrophages. Reverse transcription-quantitative polymerase chain reaction was used to investigate cellular IRF5 gene expression. Levels of proinflammatory cytokines and IRF5 were assessed following cell culture and cellular homogenization using enzyme-linked immunosorbent assay. IRF5 protein and nuclei co-localization was performed in macrophages with laser scanning confocal microscope immunofluorescence analysis. The results of the present study demonstrated that mangiferin significantly inhibits LPS/IFN-γ stimulation-induced classical activation of macrophages in vitro and markedly decreases proinflammatory cytokine release. In addition, cellular IRF5 expression was markedly downregulated. These results suggest that the inhibitory effect of mangiferin on classical activation of macrophages may be exerted via downregulation of cellular IRF5 expression levels. PMID:27277156

  3. Interferon Regulatory Factor 7 Functions as a Novel Negative Regulator of Pathological Cardiac Hypertrophy

    Science.gov (United States)

    Jiang, Ding-Sheng; Liu, Yu; Zhou, Heng; Zhang, Yan; Zhang, Xiao-Dong; Zhang, Xiao-Fei; Chen, Ke; Gao, Lu; Peng, Juan; Gong, Hui; Chen, Yingjie; Yang, Qinglin; Liu, Peter P.; Fan, Guo-Chang; Zou, Yunzeng; Li, Hongliang

    2017-01-01

    Cardiac hypertrophy is a complex pathological process that involves multiple factors including inflammation and apoptosis. Interferon regulatory factor 7 (IRF7) is a multifunctional regulator that participates in immune regulation, cell differentiation, apoptosis, and oncogenesis. However, the role of IRF7 in cardiac hypertrophy remains unclear. We performed aortic banding in cardiac-specific IRF7 transgenic mice, IRF7 knockout mice, and the wild-type littermates of these mice. Our results demonstrated that IRF7 was downregulated in aortic banding–induced animal hearts and cardiomyocytes that had been treated with angiotensin II or phenylephrine for 48 hours. Accordingly, heart-specific overexpression of IRF7 significantly attenuated pressure overload–induced cardiac hypertrophy, fibrosis, and dysfunction, whereas loss of IRF7 led to opposite effects. Moreover, IRF7 protected against angiotensin II–induced cardiomyocyte hypertrophy in vitro. Mechanistically, we identified that IRF7-dependent cardioprotection was mediated through IRF7 binding to inhibitor of κB kinase-β, and subsequent nuclear factor-κB inactivation. In fact, blocking nuclear factor-κB signaling with cardiac-specific inhibitors of κBαS32A/S36A super-repressor transgene counteracted the adverse effect of IRF7 deficiency. Conversely, activation of nuclear factor-κB signaling via a cardiac-specific conditional inhibitor of κB kinase-βS177E/S181E (constitutively active) transgene negated the antihypertrophic effect of IRF7 overexpression. Our data demonstrate that IRF7 acts as a novel negative regulator of pathological cardiac hypertrophy by inhibiting nuclear factor-κB signaling and may constitute a potential therapeutic target for pathological cardiac hypertrophy. PMID:24396025

  4. Interferon regulatory factor 7 functions as a novel negative regulator of pathological cardiac hypertrophy.

    Science.gov (United States)

    Jiang, Ding-Sheng; Liu, Yu; Zhou, Heng; Zhang, Yan; Zhang, Xiao-Dong; Zhang, Xiao-Fei; Chen, Ke; Gao, Lu; Peng, Juan; Gong, Hui; Chen, Yingjie; Yang, Qinglin; Liu, Peter P; Fan, Guo-Chang; Zou, Yunzeng; Li, Hongliang

    2014-04-01

    Cardiac hypertrophy is a complex pathological process that involves multiple factors including inflammation and apoptosis. Interferon regulatory factor 7 (IRF7) is a multifunctional regulator that participates in immune regulation, cell differentiation, apoptosis, and oncogenesis. However, the role of IRF7 in cardiac hypertrophy remains unclear. We performed aortic banding in cardiac-specific IRF7 transgenic mice, IRF7 knockout mice, and the wild-type littermates of these mice. Our results demonstrated that IRF7 was downregulated in aortic banding-induced animal hearts and cardiomyocytes that had been treated with angiotensin II or phenylephrine for 48 hours. Accordingly, heart-specific overexpression of IRF7 significantly attenuated pressure overload-induced cardiac hypertrophy, fibrosis, and dysfunction, whereas loss of IRF7 led to opposite effects. Moreover, IRF7 protected against angiotensin II-induced cardiomyocyte hypertrophy in vitro. Mechanistically, we identified that IRF7-dependent cardioprotection was mediated through IRF7 binding to inhibitor of κB kinase-β, and subsequent nuclear factor-κB inactivation. In fact, blocking nuclear factor-κB signaling with cardiac-specific inhibitors of κBα(S32A/S36A) super-repressor transgene counteracted the adverse effect of IRF7 deficiency. Conversely, activation of nuclear factor-κB signaling via a cardiac-specific conditional inhibitor of κB kinase-β(S177E/S181E) (constitutively active) transgene negated the antihypertrophic effect of IRF7 overexpression. Our data demonstrate that IRF7 acts as a novel negative regulator of pathological cardiac hypertrophy by inhibiting nuclear factor-κB signaling and may constitute a potential therapeutic target for pathological cardiac hypertrophy.

  5. Inferring regulatory element landscapes and transcription factor networks from cancer methylomes.

    Science.gov (United States)

    Yao, Lijing; Shen, Hui; Laird, Peter W; Farnham, Peggy J; Berman, Benjamin P

    2015-05-21

    Recent studies indicate that DNA methylation can be used to identify transcriptional enhancers, but no systematic approach has been developed for genome-wide identification and analysis of enhancers based on DNA methylation. We describe ELMER (Enhancer Linking by Methylation/Expression Relationships), an R-based tool that uses DNA methylation to identify enhancers and correlates enhancer state with expression of nearby genes to identify transcriptional targets. Transcription factor motif analysis of enhancers is coupled with expression analysis of transcription factors to infer upstream regulators. Using ELMER, we investigated more than 2,000 tumor samples from The Cancer Genome Atlas. We identified networks regulated by known cancer drivers such as GATA3 and FOXA1 (breast cancer), SOX17 and FOXA2 (endometrial cancer), and NFE2L2, SOX2, and TP63 (squamous cell lung cancer). We also identified novel networks with prognostic associations, including RUNX1 in kidney cancer. We propose ELMER as a powerful new paradigm for understanding the cis-regulatory interface between cancer-associated transcription factors and their functional target genes.

  6. Quantitative comparison of the expression of myogenic regulatory factors in flounder(Paralichthys olivaceus) embryos and adult tissues

    Institute of Scientific and Technical Information of China (English)

    张玉青; 谭训刚; 徐芃; 孙威; 徐永立; 张培军

    2010-01-01

    MyoD,Myf5,and myogenin are myogenic regulatory factors that play important roles during myogenesis.It is thought that MyoD and Myf5 are required for myogenic determination,while myogenin is important for terminal differentiation and lineage maintenance.To better understand the function of myogenic regulatory factors in muscle development of flounder,an important economic fish in Asia,real-time quantitative RT-PCR was used to characterize the expression patterns of MyoD,Myf5, and myogenin at early stages of ...

  7. Targeted inactivation of Snail family EMT regulatory factors by a Co(III-Ebox conjugate.

    Directory of Open Access Journals (Sweden)

    Allison S Harney

    Full Text Available Snail family proteins are core EMT (epithelial-mesenchymal transition regulatory factors that play essential roles in both development and disease processes and have been associated with metastasis in carcinomas. Snail factors are required for the formation of neural crest stem cells in most vertebrate embryos, as well as for the migratory invasive behavior of these cells. Snail factors have recently been linked to the formation of cancer stem cells, and expression of Snail proteins may be associated with tumor recurrence and resistance to chemotherapy and radiotherapy. We report that Co(III-Ebox is a potent inhibitor of Snail-mediated transcriptional repression in breast cancer cells and in the neural crest of Xenopus. We further show that the activity of Co(III-Ebox can be modulated by temperature, increasing the utility of this conjugate as a Snail inhibitor in model organisms. We exploit this feature to further delineate the requirements for Snail function during neural crest development, showing that in addition to the roles that Snail factors play in neural crest precursor formation and neural crest EMT/migration, inhibition of Snail function after the onset of neural crest migration leads to a loss of neural crest derived melanocytes. Co(III-Ebox-mediated inhibition therefore provides a powerful tool for analysing the function of these core EMT factors with unparalleled temporal resolution. Moreover, the potency of Co(III-Ebox as a Snail inhibitor in breast cancer cells suggests its potential as a therapeutic inhibitor of tumor progression and metastasis.

  8. Robust dynamic balance of AP-1 transcription factors in a neuronal gene regulatory network

    Directory of Open Access Journals (Sweden)

    Schwaber James S

    2010-12-01

    Full Text Available Abstract Background The octapeptide Angiotensin II is a key hormone that acts via its receptor AT1R in the brainstem to modulate the blood pressure control circuits and thus plays a central role in the cardiac and respiratory homeostasis. This modulation occurs via activation of a complex network of signaling proteins and transcription factors, leading to changes in levels of key genes and proteins. AT1R initiated activity in the nucleus tractus solitarius (NTS, which regulates blood pressure, has been the subject of extensive molecular analysis. But the adaptive network interactions in the NTS response to AT1R, plausibly related to the development of hypertension, are not understood. Results We developed and analyzed a mathematical model of AT1R-activated signaling kinases and a downstream gene regulatory network, with structural basis in our transcriptomic data analysis and literature. To our knowledge, our report presents the first computational model of this key regulatory network. Our simulations and analysis reveal a dynamic balance among distinct dimers of the AP-1 family of transcription factors. We investigated the robustness of this behavior to simultaneous perturbations in the network parameters using a novel multivariate approach that integrates global sensitivity analysis with decision-tree methods. Our analysis implicates a subset of Fos and Jun dependent mechanisms, with dynamic sensitivities shifting from Fos-regulating kinase (FRK-mediated processes to those downstream of c-Jun N-terminal kinase (JNK. Decision-tree analysis indicated that while there may be a large combinatorial functional space feasible for neuronal states and parameters, the network behavior is constrained to a small set of AP-1 response profiles. Many of the paths through the combinatorial parameter space lead to a dynamic balance of AP-1 dimer forms, yielding a robust AP-1 response counteracting the biological variability. Conclusions Based on the simulation

  9. Identification of direct regulatory targets of the transcription factor Sox10 based on function and conservation

    Directory of Open Access Journals (Sweden)

    Lee Sanghyuk

    2008-09-01

    Full Text Available Abstract Background Sox10, a member of the Sry-related HMG-Box gene family, is a critical transcription factor for several important cell lineages, most notably the neural crest stem cells and the derivative peripheral glial cells and melanocytes. Thus far, only a handful of direct target genes are known for this transcription factor limiting our understanding of the biological network it governs. Results We describe identification of multiple direct regulatory target genes of Sox10 through a procedure based on function and conservation. By combining RNA interference technique and DNA microarray technology, we have identified a set of genes that show significant down-regulation upon introduction of Sox10 specific siRNA into Schwannoma cells. Subsequent comparative genomics analyses led to potential binding sites for Sox10 protein conserved across several mammalian species within the genomic region proximal to these genes. Multiple sites belonging to 4 different genes (proteolipid protein, Sox10, extracellular superoxide dismutase, and pleiotrophin were shown to directly interact with Sox10 by chromatin immunoprecipitation assay. We further confirmed the direct regulation through the identified cis-element for one of the genes, extracellular superoxide dismutase, using electrophoretic mobility shift assay and reporter assay. Conclusion In sum, the process of combining differential expression profiling and comparative genomics successfully led to further defining the role of Sox10, a critical transcription factor for the development of peripheral glia. Our strategy utilizing relatively accessible techniques and tools should be applicable to studying the function of other transcription factors.

  10. Elongation factor P mediates a novel post-transcriptional regulatory pathway critical for bacterial virulence

    DEFF Research Database (Denmark)

    Zou, S Betty; Roy, Hervé; Ibba, Michael;

    2012-01-01

    Bacterial pathogens detect and integrate multiple environmental signals to coordinate appropriate changes in gene expression including the selective expression of virulence factors, changes to metabolism and the activation of stress response systems. Mutations that abolish the ability of the path......Bacterial pathogens detect and integrate multiple environmental signals to coordinate appropriate changes in gene expression including the selective expression of virulence factors, changes to metabolism and the activation of stress response systems. Mutations that abolish the ability...... of the pathogen to respond to external cues are typically attenuating. Here we discuss our recent discovery of a novel post-transcriptional regulatory pathway critical for Salmonella virulence and stress resistance. The enzymes PoxA and YjeK coordinately attach a unique beta-amino acid onto a highly conserved...... our laboratory and others now suggests that EF-P, previously thought to be essential, instead plays an ancillary role in translation by regulating the synthesis of a relatively limited subset of proteins. Other observations suggest that the eukaryotic homolog of EF-P, eIF5A, may illicit similar...

  11. SNP2TFBS – a database of regulatory SNPs affecting predicted transcription factor binding site affinity

    Science.gov (United States)

    Kumar, Sunil; Ambrosini, Giovanna; Bucher, Philipp

    2017-01-01

    SNP2TFBS is a computational resource intended to support researchers investigating the molecular mechanisms underlying regulatory variation in the human genome. The database essentially consists of a collection of text files providing specific annotations for human single nucleotide polymorphisms (SNPs), namely whether they are predicted to abolish, create or change the affinity of one or several transcription factor (TF) binding sites. A SNP's effect on TF binding is estimated based on a position weight matrix (PWM) model for the binding specificity of the corresponding factor. These data files are regenerated at regular intervals by an automatic procedure that takes as input a reference genome, a comprehensive SNP catalogue and a collection of PWMs. SNP2TFBS is also accessible over a web interface, enabling users to view the information provided for an individual SNP, to extract SNPs based on various search criteria, to annotate uploaded sets of SNPs or to display statistics about the frequencies of binding sites affected by selected SNPs. Homepage: http://ccg.vital-it.ch/snp2tfbs/. PMID:27899579

  12. Dissecting role of regulatory factors in NF-κB pathway with siRNA

    Institute of Scientific and Technical Information of China (English)

    Jun GUO; Yu-cai FU; Carlos R BECERRA

    2005-01-01

    NF-κB, a family of related transcription factors, has been a focus of intense scientific research during the past decade.Multiple stimuli, both extracellular and intracellular, lead to its activation.The NF-κB pathway regulates expression of a diverse array of genes involved in different biological processes.Various pathological states are characterized by the dysregulated NF-κB pathway.Recently,NF-κB activation has been connected with multiple aspects of oncogenesis and serves as an important mechanism to regulate cell survival in response to chemotherapy by activating different genes that inhibit apoptosis.Several methods of inhibiting NF-κB activation, such as antisense oligonucleotides, proteosome inhibitors and RNA interference (RNAi) are currently under investigation.RNAi represents a powerful tool to better define the role of specific genes in different signal transduction pathways and has recently been used to define the function of genes that regulate the NF-κB pathway.This review discusses the emerging role of RNAi to dissect the function of regulatory factors in the NF-κB pathway and its potential use as a targeted therapy.

  13. Advances in Translational Medicine of Liver Regeneration-Associated Regulatory Factors

    Institute of Scientific and Technical Information of China (English)

    HAN Jin-bin; MA Cong; SHI Yan-qiong

    2016-01-01

    The liver is an important organ that has strong regeneration and defensive ability in human body. The cell types participating in liver regeneration have close association with the severity of liver injury. When the liver is in mild injury, it mainly repairs the injury through the cellular proliferation of liver parenchyma, whereas when the liver is in severe injury complicated with liver cell aplasia, the liver tissues will launch stem cell proliferative responses. Liver cells and stem cells have different responses to injury, so there may be specific regulation of signal routines and factors. Translational medicine mainly guides clinical practice through basic research, which not only promotes the development of modern medicine, but also is the strong impetus that promotes the development of modern medicine. The application of translational medicine has greatly improved the therapeutic efifcacy of liver surgery, liver cancer and liver transplantation around the world. This study mainly reviewed the advances in translational medicine of liver regeneration-associated regulatory factors, hoping to provide references for the clinical diagnosis and treatment of liver diseases.

  14. Opposing roles for interferon regulatory factor-3 (IRF-3 and type I interferon signaling during plague.

    Directory of Open Access Journals (Sweden)

    Ami A Patel

    Full Text Available Type I interferons (IFN-I broadly control innate immunity and are typically transcriptionally induced by Interferon Regulatory Factors (IRFs following stimulation of pattern recognition receptors within the cytosol of host cells. For bacterial infection, IFN-I signaling can result in widely variant responses, in some cases contributing to the pathogenesis of disease while in others contributing to host defense. In this work, we addressed the role of type I IFN during Yersinia pestis infection in a murine model of septicemic plague. Transcription of IFN-β was induced in vitro and in vivo and contributed to pathogenesis. Mice lacking the IFN-I receptor, Ifnar, were less sensitive to disease and harbored more neutrophils in the later stage of infection which correlated with protection from lethality. In contrast, IRF-3, a transcription factor commonly involved in inducing IFN-β following bacterial infection, was not necessary for IFN production but instead contributed to host defense. In vitro, phagocytosis of Y. pestis by macrophages and neutrophils was more effective in the presence of IRF-3 and was not affected by IFN-β signaling. This activity correlated with limited bacterial growth in vivo in the presence of IRF-3. Together the data demonstrate that IRF-3 is able to activate pathways of innate immunity against bacterial infection that extend beyond regulation of IFN-β production.

  15. Distribution of sterols in the fungi. I - Fungal spores

    Science.gov (United States)

    Weete, J. D.; Laseter, J. L.

    1974-01-01

    Mass spectrometry was used to examine freely extractable sterols from spores of several species of fungi. Ergosterol was the most common sterol produced by any individual species, but it was completely absent from two species belonging to apparently distantly related groups of fungi: the aquatic Phycomycetes and the rust fungi. This fact could have taxonomic or phylogenetic implications. The use of glass capillary columns in the resolution of the sterols is shown to eliminate some of the difficulty inherent in this process.

  16. Distribution of sterols in the fungi. I - Fungal spores

    Science.gov (United States)

    Weete, J. D.; Laseter, J. L.

    1974-01-01

    Mass spectrometry was used to examine freely extractable sterols from spores of several species of fungi. Ergosterol was the most common sterol produced by any individual species, but it was completely absent from two species belonging to apparently distantly related groups of fungi: the aquatic Phycomycetes and the rust fungi. This fact could have taxonomic or phylogenetic implications. The use of glass capillary columns in the resolution of the sterols is shown to eliminate some of the difficulty inherent in this process.

  17. [Plant sterols, cholesterol precursors and oxysterols: small amounts, big effects].

    Science.gov (United States)

    Olkkonen, Vesa M; Gylling, Helena; Ikonen, Elina

    2015-01-01

    Noncholesterol sterols are present in the body in very low concentrations compared with cholesterol. Minor structural changes in sterols give them completely individual biological activities. Steroid hormones are the best known example of this. The knowledge of other relatives of cholesterol, particularly plant sterols, cholesterol precursors and oxysterols, their properties, physiological effects, significance in disease processes and diagnostic applications has recently undergone a rapid increase.

  18. Cholesterol homeostasis: How do cells sense sterol excess?

    Science.gov (United States)

    Howe, Vicky; Sharpe, Laura J; Alexopoulos, Stephanie J; Kunze, Sarah V; Chua, Ngee Kiat; Li, Dianfan; Brown, Andrew J

    2016-09-01

    Cholesterol is vital in mammals, but toxic in excess. Consequently, elaborate molecular mechanisms have evolved to maintain this sterol within narrow limits. How cells sense excess cholesterol is an intriguing area of research. Cells sense cholesterol, and other related sterols such as oxysterols or cholesterol synthesis intermediates, and respond to changing levels through several elegant mechanisms of feedback regulation. Cholesterol sensing involves both direct binding of sterols to the homeostatic machinery located in the endoplasmic reticulum (ER), and indirect effects elicited by sterol-dependent alteration of the physical properties of membranes. Here, we examine the mechanisms employed by cells to maintain cholesterol homeostasis.

  19. Using graphical adaptive lasso approach to construct transcription factor and microRNA's combinatorial regulatory network in breast cancer.

    Science.gov (United States)

    Su, Naifang; Dai, Ding; Deng, Chao; Qian, Minping; Deng, Minghua

    2014-06-01

    Discovering the regulation of cancer-related gene is of great importance in cancer biology. Transcription factors and microRNAs are two kinds of crucial regulators in gene expression, and they compose a combinatorial regulatory network with their target genes. Revealing the structure of this network could improve the authors' understanding of gene regulation, and further explore the molecular pathway in cancer. In this article, the authors propose a novel approach graphical adaptive lasso (GALASSO) to construct the regulatory network in breast cancer. GALASSO use a Gaussian graphical model with adaptive lasso penalties to integrate the sequence information as well as gene expression profiles. The simulation study and the experimental profiles verify the accuracy of the authors' approach. The authors further reveal the structure of the regulatory network, and explore the role of feedforward loops in gene regulation. In addition, the authors discuss the combinatorial regulatory effect between transcription factors and microRNAs, and select miR-155 for detailed analysis of microRNA's role in cancer. The proposed GALASSO approach is an efficient method to construct the combinatorial regulatory network. It also provides a new way to integrate different data sources and could find more applications in meta-analysis problem.

  20. A deeper look into transcription regulatory code by preferred pair distance templates for transcription factor binding sites

    KAUST Repository

    Kulakovskiy, Ivan V.

    2011-08-18

    Motivation: Modern experimental methods provide substantial information on protein-DNA recognition. Studying arrangements of transcription factor binding sites (TFBSs) of interacting transcription factors (TFs) advances understanding of the transcription regulatory code. Results: We constructed binding motifs for TFs forming a complex with HIF-1α at the erythropoietin 3\\'-enhancer. Corresponding TFBSs were predicted in the segments around transcription start sites (TSSs) of all human genes. Using the genome-wide set of regulatory regions, we observed several strongly preferred distances between hypoxia-responsive element (HRE) and binding sites of a particular cofactor protein. The set of preferred distances was called as a preferred pair distance template (PPDT). PPDT dramatically depended on the TF and orientation of its binding sites relative to HRE. PPDT evaluated from the genome-wide set of regulatory sequences was used to detect significant PPDT-consistent binding site pairs in regulatory regions of hypoxia-responsive genes. We believe PPDT can help to reveal the layout of eukaryotic regulatory segments. © The Author 2011. Published by Oxford University Press. All rights reserved.

  1. Expression regulation of zebrafish interferon regulatory factor 9 by promoter analysis.

    Science.gov (United States)

    Shi, Jun; Zhang, Yi-Bing; Zhang, Jian-She; Gui, Jian-Fang

    2013-12-01

    We previously showed that a fish interferon (IFN) regulatory factor 9 (IRF9) homologue, crucian carp Carassius auratus IRF9, displays constitutively nuclear localization and involvement in fish IFN-dependent JAK-STAT signaling; however, little is known about the expression regulation of fish IRF9. Here, we characterized the expression of zebrafish IRF9 by promoter analysis. Zebrafish IRF9 gene promoter contained several putative transcription factor binding sites, including one ISRE (IFN-stimulated response element), one GAS (IFN gamma activation sequence) and three GATEs (IFNγ activated transcriptional element, GATE1/2/3). Further sequence analyses revealed that GAS and GATE motifs existed in all promoters of IRF9 from mammals and fishes. Luciferase assays confirmed that zebrafish IRF9 promoter could be activated by zebrafish IFNφs and zebrafish IFNγ2, as well as transcription factors IRF3, IRF7, and combination of IRF9 and STAT2. Treatment of recombinant crucian carp IFN protein or overexpression of zebrafish IFNγ2 both led to significant increase in crucian carp IRF9 mRNA and protein in cultured fish cells. Comparison of IFN-stimulated promoter activity revealed much more significant induction of zebrafish IRF9 by zebrafish IFNγ2 than by zebrafish IFNφs. Mutation analyses showed that the putative GAS and GATE3 contributed to zebrafish IFNγ2-triggered IRF9 expression, whereas the putative ISRE and the other two GATEs were not functional for induction of zebrafish IRF9. These results together indicated that the expression property of IRF9 might be conserved from fish to mammals and that some not yet identified mechanisms could exist in IRF9 gene transcription regulation in response to IFNs.

  2. Is the iron regulatory hormone hepcidin a risk factor for alcoholic liver disease?

    Institute of Scientific and Technical Information of China (English)

    Duygu Dee Harrison-Findik

    2009-01-01

    Despite heavy consumption over a long period of time,only a small number of alcoholics develop alcoholic liver disease. This alludes to the possibility that other factors,besides alcohol, may be involved in the progression of the disease. Over the years, many such factors have indeed been identified, including iron. Despite being crucial for various important biological processes, iron can also be harmful due to its ability to catalyze Fenton chemistry. Alcohol and iron have been shown to interact synergistically to cause liver injury. Iron-mediated cell signaling has been reported to be involved in the pathogenesis of experimental alcoholic liver disease. Hepcidin is an iron-regulatory hormone synthesized by the liver,which plays a pivotal role in iron homeostasis. Both acute and chronic alcohol exposure suppress hepcidin expression in the liver. The sera of patients with alcoholic liver disease, particularly those exhibiting higher serum iron indices, have also been reported to display reduced prohepcidin levels. Alcohol-mediated oxidative stress is involved in the inhibition of hepcidin promoter activity and transcription in the liver. This in turn leads to an increase in intestinal iron transport and liver iron storage. Hepcidin is expressed primarily in hepatocytes.It is noteworthy that both hepatocytes and Kupffer cells are involved in the progression of alcoholic liver disease. However, the activation of Kupffer cells and TNF-α signaling has been reported not to be involved in the down-regulation of hepcidin expression by alcohol in the liver. Alcohol acts within the parenchymal cells of the liver to suppress the synthesis of hepcidin. Due to its crucial role in the regulation of body iron stores, hepcidin may act as a secondary risk factor in the progression of alcoholic liver disease. The clarification of the mechanisms by which alcohol disrupts iron homeostasis will allow for further understanding of the pathogenesis of alcoholic liver disease.

  3. Functional Development of the Human Gastrointestinal Tract: Hormone- and Growth Factor-Mediated Regulatory Mechanisms

    Directory of Open Access Journals (Sweden)

    Daniel Ménard

    2004-01-01

    Full Text Available The present review focuses on the control of gastrointestinal (GI tract development. The first section addresses the differences in general mechanisms of GI development in humans versus rodents, highlighting that morphogenesis of specific digestive organs and the differentiation of digestive epithelia occur not only at different stages of ontogeny but also at different rates. The second section provides an overview of studies from the author's laboratory at the Université de Sherbrooke pertaining to the development of the human fetal small intestine and colon. While both segments share similar morphological and functional characteristics, they are nevertheless modulated by distinct regulatory mechanisms. Using the organ culture approach, the author and colleagues were able to establish that hormones and growth factors, such as glucocorticoids, epidermal growth factor, insulin and keratinocyte growth factor, not only exert differential effects within these two segments, they can also trigger opposite responses in comparison with animal models. In the third section, emphasis is placed on the functional development of human fetal stomach and its various epithelial cell types; in particular, the glandular chief cells responsible for the synthesis and secretion of gastric enzymes such as pepsinogen-5 and gastric lipase. Bearing in mind that limitations of available cell models have, until now, greatly impeded the comprehension of molecular mechanisms regulating human gastric epithelial cell functions, the last section focuses on new human gastric epithelial cell models recently developed in the author's laboratory. These models comprise a novel primary culture system of human fetal gastric epithelium including, for the first time, functional chief cells, and human gastric epithelium cell lines cloned from the parental NCI-N87 strain. These new cells lines could serve important applications in the study of pathogenic action and epithelial

  4. Interferon Regulatory Factor 7 Promoted Glioblastoma Progression and Stemness by Modulating IL-6 Expression in Microglia

    Science.gov (United States)

    Li, Zongze; Huang, Qiming; Chen, Heping; Lin, Zhiqin; Zhao, Meng; Jiang, Zhongli

    2017-01-01

    Background: Interferon Regulatory Factor 7 (IRF7) is associated with chronic inflammation initiated by the activation of microglia. However it remains poorly defined how IRF7 activates microglia to initiate inflammatory microenvironment, and thus promotes the growth and malignancy of glioblastoma multiforme (GBM). This study investigated the role of IRF7 expression in microglia which increases GBM progression. Methods: We established stable human microglia (HMs) over-expressing IRF-7 or empty vector by lentiviral transduction and stable selection. These HM-IRF-7 cells were co-cultured with U87-MG to examine their influence on GBM, in terms of cell proliferation, apoptosis and stemness of U87-MG. By qRT-PCR and ELISA assays, the expression of key genes and secretion of inflammatory factors were identified in inflammatory signal pathway respectively. We also analyzed whether the expression of IRF7 and its target gene IL-6 correlated with PFS (progression-free survival) and OS (overall survival) in clinical samples by Kaplan-Meier survival curves. Results: HMs can be engineered to stably express high level of IFR7 with IRF7 lentivirus, and was found to promote U87-MG growth and inhibit its apoptosis in co-culture. Meanwhile, U87-MG seemed to show stem cell character with ALDH1 expression. These results may be related to IRF7 initiating IL-6 expression and secretion in both HM and U87-MG cells. The IRF7 and IL-6 were highly expressed in GBM tissues, and IL-6 secretion was high in GBM serums, both of which were significantly correlated with PFS and OS. Conclusions: The immune function of HMs was changed while it expressed IRF7 genes. The results demonstrated for the first time that IRF7 of microglia promoted GBM growth and stemness by mediating IL-6 expression, and revealed that IRF-7 and IL-6 were independent factors affecting the overall survival probability.

  5. Environmental and state-level regulatory factors affect the incidence of autism and intellectual disability.

    Directory of Open Access Journals (Sweden)

    Andrey Rzhetsky

    2014-03-01

    Full Text Available Many factors affect the risks for neurodevelopmental maladies such as autism spectrum disorders (ASD and intellectual disability (ID. To compare environmental, phenotypic, socioeconomic and state-policy factors in a unified geospatial framework, we analyzed the spatial incidence patterns of ASD and ID using an insurance claims dataset covering nearly one third of the US population. Following epidemiologic evidence, we used the rate of congenital malformations of the reproductive system as a surrogate for environmental exposure of parents to unmeasured developmental risk factors, including toxins. Adjusted for gender, ethnic, socioeconomic, and geopolitical factors, the ASD incidence rates were strongly linked to population-normalized rates of congenital malformations of the reproductive system in males (an increase in ASD incidence by 283% for every percent increase in incidence of malformations, 95% CI: [91%, 576%], p<6×10(-5. Such congenital malformations were barely significant for ID (94% increase, 95% CI: [1%, 250%], p = 0.0384. Other congenital malformations in males (excluding those affecting the reproductive system appeared to significantly affect both phenotypes: 31.8% ASD rate increase (CI: [12%, 52%], p<6×10(-5, and 43% ID rate increase (CI: [23%, 67%], p<6×10(-5. Furthermore, the state-mandated rigor of diagnosis of ASD by a pediatrician or clinician for consideration in the special education system was predictive of a considerable decrease in ASD and ID incidence rates (98.6%, CI: [28%, 99.99%], p = 0.02475 and 99% CI: [68%, 99.99%], p = 0.00637 respectively. Thus, the observed spatial variability of both ID and ASD rates is associated with environmental and state-level regulatory factors; the magnitude of influence of compound environmental predictors was approximately three times greater than that of state-level incentives. The estimated county-level random effects exhibited marked spatial clustering, strongly

  6. Plant sterols for adults with hypercholesterolemia treated with or without medication (statins

    Directory of Open Access Journals (Sweden)

    Raquel Bernácer

    2015-07-01

    Full Text Available Hypercholesterolemia is the most common coronary risk factor among the Spanish population; 37.4% of the Spanish adult population have cholesterol levels between 190 and 240 mg/dl. Foods enriched with plant sterols (PS can effectively reduce plasma cholesterol in patients with high levels. However, its effectiveness and safety in adults with moderate hypercholesterolemia who are on medication (statins or not has been less studied. The aim of this review is to establish the possible role of plant sterols in the control of hypercholesterolemia, as well as how safe they are for people with moderate hypercholesterolemia treated with statins. The main studies were looked at, regardless of design, language or publication date which studied the connection between “plant sterols” and “hypercholesterolemia”, using Pubmed/Medline, SCOPUS and Google Scholar databases. The studies brought together in this review show that an intake of between 2 and 3g/day of plant sterols effectively reduces plasma cholesterol levels in patients with hypercholesterolemia. Both clinical studies and available meta-analyses do not indicate any problems related to the drug-nutrient interaction associated with the use of plant sterol-enriched foods. In patients with moderate hypercholesterolemia where the use of statins is not justified a healthy diet, exercise and foods high in PS can provide the best therapeutic approach.

  7. Biosynthesis of sterols and triterpenes in cell suspension cultures of Uncaria tomentosa.

    Science.gov (United States)

    Flores-Sánchez, Isvett J; Ortega-López, Jaime; del Carmen Montes-Horcasitas, María; Ramos-Valdivia, Ana C

    2002-12-01

    Pectin administered to Uncaria tomentosa cell suspension cultures, was found to increase the production of triterpene acids (ursolic and oleanolic acid), however, neither growth nor sterol accumulation were affected. Cell cultures showed that pectin treatment caused a rapid threefold increase in the activities of enzymes involved in the biosynthesis of C(5) and C(30 )isoprenoid, such as isopentenyl diphosphate isomerase and squalene synthase. The activity of a farnesyl diphosphatase, which could divert the flux of farnesyl diphosphate to farnesol, was two times lower in elicited than in control cells. Elicited cells also transformed more rapidly a higher percentage of [5-(3)H]mevalonic acid into triterpene acids. Interestingly, addition of terbinafine, an inhibitor of squalene epoxidase, to elicited cell cultures inhibited sterol accumulation while triterpene production was not inhibited. These results suggest that in U. tomentosa cells, both the previously mentioned enzymes and those involved in squalene 2,3-oxide formation play an important regulatory role in the biosynthesis of sterols and triterpenes.

  8. Mitochondrial function and regulation of macrophage sterol metabolism and inflammatory responses

    Institute of Scientific and Technical Information of China (English)

    Annette; Graham; Anne-Marie; Allen

    2015-01-01

    The aim of this review is to explore the role of mitochondria in regulating macrophage sterol homeostasis and inflammatory responses within the aetiology of atherosclerosis.Macrophage generation of oxysterol activators of liver X receptors(LXRs),via sterol 27-hydroxylase,is regulated by the rate of flux of cholesterolto the inner mitochondrial membrane,via a complex of cholesterol trafficking proteins.Oxysterols are key signalling molecules,regulating the transcriptional activity of LXRs which coordinate macrophage sterol metabolism and cytokine production,key features influencing the impact of these cells within atherosclerotic lesions.The precise identity of the complex of proteins mediating mitochondrial cholesterol trafficking in macrophages remains a matter of debate,but may include steroidogenic acute regulatory protein and translocator protein.There is clear evidence that targeting either of these proteins enhances removal of cholesterol via LXRα-dependent induction of ATP binding cassette transporters(ABCA1,ABCG1) and limits the production of inflammatory cytokines; interventions which influence mitochondrial structure and bioenergetics also impact on removal of cholesterol from macrophages.Thus,molecules which can sustain or improve mitochondrial structure,the function of the electron transport chain,or increase the activity of components of the protein complex involved in cholesterol transfer,may therefore have utility in limiting or regressing atheroma development,reducing the incidence of coronary heart disease and myocardial infarction.

  9. Involvement of heme biosynthesis in control of sterol uptake by Saccharomyces cerevisiae.

    OpenAIRE

    Lewis, T A; Taylor, F R; Parks, L W

    1985-01-01

    Wild-type Saccharomyces cerevisiae do not accumulate exogenous sterols under aerobic conditions, and a mutant allele conferring sterol auxotrophy (erg7) could be isolated only in strains with a heme deficiency. delta-Aminolevulinic acid (ALA) fed to a hem1 (ALA synthetase-) erg7 (2,3-oxidosqualene cyclase-) sterol-auxotrophic strain of S. cerevisiae inhibited sterol uptake, and growth was negatively affected when intracellular sterol was depleted. The inhibition of sterol uptake (and growth o...

  10. Spermatogenesis associated 4 promotes Sertoli cell proliferation modulated negatively by regulatory factor X1.

    Directory of Open Access Journals (Sweden)

    Junjun Jiang

    Full Text Available Spermatogenesis associated 4 (Spata4, a testis-specific and CpG island associated gene, is involved in regulating cell proliferation, differentiation and apoptosis. To obtain insight into the role of Spata4 in cell cycling control, we characterized the promoter region of Spata4 and investigated its transcriptional regulation mechanism. The Spata4 promoter is unidirectional transcribed and possesses multiple transcription start sites. Moreover, we present evidence that regulatory factor X1 (RFX1 could bind the typical 14-bp cis-elements of Spata4 promoter, modulate transcriptional activity and endogenous expression of Spata4, and further regulate the proliferation of Sertoli cells. Overexpression of RFX1 was shown to down-regulate both the promoter activity and mRNA expression of Spata4, whereas knockdown of RFX1 demonstrated the opposite effects. Our studies provide insight into Spata4 gene regulation and imply the potential role of RFX1 in growth of Sertoli cells. RFX1 may have negative effect on cell proliferation of Sertoli cells via modulating Spata4 expression levels by binding the conserved 14-bp cis-elements of Spata4 promoter.

  11. Effects of oral creatine and resistance training on myogenic regulatory factor expression.

    Science.gov (United States)

    Willoughby, Darryn S; Rosene, John M

    2003-06-01

    This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on skeletal muscle creatine kinase (M-CK) mRNA expression and the mRNA and protein expression of the myogenic regulatory factors Myo-D, myogenin, MFR-4, and Myf5. Twenty-two untrained males were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after training. PLC and CRT trained thrice weekly using 3 sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk while PLC consumed the equal amount of placebo. After training, M-CK mRNA expression, as well as myogenin and MRF-4 mRNA and protein expression, were found to be significantly greater for CRT compared with PLC and CON, whereas PLC was also significantly different from CON (P 0.05). M-CK mRNA was correlated with myogenin (r = 0.916) and MRF-4 (r = 0.883) protein (P resistance training, Cr supplementation increases M-CK mRNA expression, likely due to concomitant increases in the expression of myogenin and MRF-4. Therefore, increases in myogenin and MRF-4 mRNA and protein may play a role in increasing myosin heavy chain expression, already shown to occur with Cr supplementation.

  12. Myogenic regulatory factor (MRF) expression is affected by exercise in postnatal chicken skeletal muscles.

    Science.gov (United States)

    Yin, Huadong; Li, Diyan; Wang, Yan; Zhao, Xiaoling; Liu, Yiping; Yang, Zhiqin; Zhu, Qing

    2015-05-01

    The MyoD1, MyoG, Myf5, and Mrf4 proteins belong to the family of muscle regulatory factors (MRFs) and play important roles in skeletal muscle hyperplasia and hypertrophy. We hypothesized that exercise would affect MRF mRNA and protein abundance in postnatal chicken skeletal muscle driving molecular changes that could ultimately lead to increased muscle fiber diameter. At day (d) 43, twelve hundred chickens with similar body weight were randomly assigned to cage, pen, and free-range groups. The MRF mRNA abundance was measured in the pectoralis major and thigh muscle at d56, d70, and d84, and the protein levels of MRFs were determined from the thigh muscle at d84. The results showed no significant difference in mRNA of the MRFs among the three groups at d56 (P>0.05). At d84, chicken in the pen and free-range group showed higher MyoD1, MyoG, Myf5, and Mrf4 mRNA abundance compared to the caged chickens (Pchickens had higher Mrf4 and MyoG expression than those in penned ones (Pchickens (Pchickens.

  13. Affinity Density: a novel genomic approach to the identification of transcription factor regulatory targets.

    Science.gov (United States)

    Hazelett, Dennis J; Lakeland, Daniel L; Weiss, Joseph B

    2009-07-01

    A new method was developed for identifying novel transcription factor regulatory targets based on calculating Local Affinity Density. Techniques from the signal-processing field were used, in particular the Hann digital filter, to calculate the relative binding affinity of different regions based on previously published in vitro binding data. To illustrate this approach, the complete genomes of Drosophila melanogaster and D.pseudoobscura were analyzed for binding sites of the homeodomain proteinc Tinman, an essential heart development gene in both Drosophila and Mouse. The significant binding regions were identified relative to genomic background and assigned to putative target genes. Valid candidates common to both species of Drosophila were selected as a test of conservation. The new method was more sensitive than cluster searches for conserved binding motifs with respect to positive identification of known Tinman targets. Our Local Affinity Density method also identified a significantly greater proportion of Tinman-coexpressed genes than equivalent, optimized cluster searching. In addition, this new method predicted a significantly greater than expected number of genes with previously published RNAi phenotypes in the heart. Algorithms were implemented in Python, LISP, R and maxima, using MySQL to access locally mirrored sequence data from Ensembl (D.melanogaster release 4.3) and flybase (D.pseudoobscura). All code is licensed under GPL and freely available at http://www.ohsu.edu/cellbio/dev_biol_prog/affinitydensity/.

  14. Are good ideas enough? The impact of socio-economic and regulatory factors on GMO commercialisation.

    Science.gov (United States)

    Vàzquez-Salat, Núria

    2013-01-01

    In recent years scientific literature has seen an increase in publications describing new transgenic applications. Although technically-sound, these promising developments might not necessarily translate into products available to the consumer. This article highlights the impact of external factors on the commercial viability of Genetically Modified (GM) animals in the pharmaceutical and food sectors. Through the division of the production chain into three Policy Domains -Science, Market and Public- I present an overview of the broad range of regulatory and socio-economic components that impacts on the path towards commercialisation of GM animals. To further illustrate the unique combination of forces that influence each application, I provide an in-depth analysis of two real cases: GM rabbits producing human polyclonal antibodies (pharmaceutical case study) and GM cows producing recombinant human lactoferrin (food case study). The inability to generalise over the commercial success of a given transgenic application should encourage researchers to perform these type of exercises early in the R & D process. Furthermore, through the analysis of these case studies we can observe a change in the biopolitics of Genetically Modified Organisms (GMOs). Contrary to the GM plant biopolitical landscape, developing states such as China and Argentina are placing themselves as global leaders in GM animals. The pro-GM attitude of these states is likely to cause a shift in the political evolution of global GMO governance.

  15. Interferon regulatory factor 4 attenuates Notch signaling to suppress the development of chronic lymphocytic leukemia.

    Science.gov (United States)

    Shukla, Vipul; Shukla, Ashima; Joshi, Shantaram S; Lu, Runqing

    2016-07-05

    Molecular pathogenesis of Chronic Lymphocytic Leukemia (CLL) is not fully elucidated. Genome wide association studies have linked Interferon Regulatory Factor 4 (IRF4) to the development of CLL. We recently established a causal relationship between low levels of IRF4 and development of CLL. However, the molecular mechanism through which IRF4 suppresses CLL development remains unclear. Deregulation of Notch signaling pathway has been identified as one of the most recurrent molecular anomalies in the pathogenesis of CLL. Yet, the role of Notch signaling as well as its regulation during CLL development remains poorly understood. Previously, we demonstrated that IRF4 deficient mice expressing immunoglobulin heavy chain Vh11 (IRF4-/-Vh11) developed spontaneous CLL with complete penetrance. In this study, we show that elevated Notch2 expression and the resulting hyperactivation of Notch signaling are common features of IRF4-/-Vh11 CLL cells. Our studies further reveal that Notch signaling is indispensable for CLL development in the IRF4-/-Vh11 mice. Moreover, we identify E3 ubiquitin ligase Nedd4, which targets Notch for degradation, as a direct target of IRF4 in CLL cells and their precursors. Collectively, our studies provide the first in vivo evidence for an essential role of Notch signaling in the development of CLL and establish IRF4 as a critical regulator of Notch signaling during CLL development.

  16. SUPLEMENTASI STEROL LEMBAGA GANDUM (Triticum sp. PADA MARGARIN (Supplementation of Margarine with Wheat Germ Sterol

    Directory of Open Access Journals (Sweden)

    Sri Anna Marliyati1*

    2010-06-01

    Full Text Available Margarine is a water in oil (w/o emulsion product which is widely used for household cooking and baking industry. Consuming of margarine, which contains trans fatty acid may cause health problem due to the increase of LDL cholesterol. Since margarine is also a good carrier of phytosterol which prevent the absorption of cholesterol, there is a possibility to formulate a healthier margarine. In this research formulation and characteristics of products was investigated. The research work consisted of two steps: (1 supplementation of wheat germ sterol into margarine (two methods and (2 analysis of physical, chemical characteristics and hedonic score. Parameters of physical characteristics were melting point and emulsion stability, whereas chemical characteristics were water and oil contents. The hedonic test was carried out based on product’s color, odor, taste, texture, and spreadability. Results showed that method II of supplementation produced better margarine than method I, in which the concentration of sterol in the margarine was higher with a melting point similar to that of control, better emulsion stability, and higher hedonic score. Supplementation process was carried out by mixing sterol into fat phase melted at 50 0C, followed by mixing with aqueous phase at 4 0C. Sterol used for method II was extracted using mixed solvent of hexane and ethanol at the ratio of 1:2 (v/v, which was resulted from previous experimentation.

  17. FOXA and master transcription factors recruit Mediator and Cohesin to the core transcriptional regulatory circuitry of cancer cells

    Science.gov (United States)

    Fournier, Michèle; Bourriquen, Gaëlle; Lamaze, Fabien C.; Côté, Maxime C.; Fournier, Éric; Joly-Beauparlant, Charles; Caron, Vicky; Gobeil, Stéphane; Droit, Arnaud; Bilodeau, Steve

    2016-10-01

    Controlling the transcriptional program is essential to maintain the identity and the biological functions of a cell. The Mediator and Cohesin complexes have been established as central cofactors controlling the transcriptional program in normal cells. However, the distribution, recruitment and importance of these complexes in cancer cells have not been fully investigated. Here we show that FOXA and master transcription factors are part of the core transcriptional regulatory circuitry of cancer cells and are essential to recruit M ediator and Cohesin. Indeed, Mediator and Cohesin occupied the enhancer and promoter regions of actively transcribed genes and maintained the proliferation and colony forming potential. Through integration of publically available ChIP-Seq datasets, we predicted the core transcriptional regulatory circuitry of each cancer cell. Unexpectedly, for all cells investigated, the pioneer transcription factors FOXA1 and/or FOXA2 were identified in addition to cell-specific master transcription factors. Loss of both types of transcription factors phenocopied the loss of Mediator and Cohesin. Lastly, the master and pioneer transcription factors were essential to recruit Mediator and Cohesin to regulatory regions of actively transcribed genes. Our study proposes that maintenance of the cancer cell state is dependent on recruitment of Mediator and Cohesin through FOXA and master transcription factors.

  18. FOXA and master transcription factors recruit Mediator and Cohesin to the core transcriptional regulatory circuitry of cancer cells.

    Science.gov (United States)

    Fournier, Michèle; Bourriquen, Gaëlle; Lamaze, Fabien C; Côté, Maxime C; Fournier, Éric; Joly-Beauparlant, Charles; Caron, Vicky; Gobeil, Stéphane; Droit, Arnaud; Bilodeau, Steve

    2016-10-14

    Controlling the transcriptional program is essential to maintain the identity and the biological functions of a cell. The Mediator and Cohesin complexes have been established as central cofactors controlling the transcriptional program in normal cells. However, the distribution, recruitment and importance of these complexes in cancer cells have not been fully investigated. Here we show that FOXA and master transcription factors are part of the core transcriptional regulatory circuitry of cancer cells and are essential to recruit M ediator and Cohesin. Indeed, Mediator and Cohesin occupied the enhancer and promoter regions of actively transcribed genes and maintained the proliferation and colony forming potential. Through integration of publically available ChIP-Seq datasets, we predicted the core transcriptional regulatory circuitry of each cancer cell. Unexpectedly, for all cells investigated, the pioneer transcription factors FOXA1 and/or FOXA2 were identified in addition to cell-specific master transcription factors. Loss of both types of transcription factors phenocopied the loss of Mediator and Cohesin. Lastly, the master and pioneer transcription factors were essential to recruit Mediator and Cohesin to regulatory regions of actively transcribed genes. Our study proposes that maintenance of the cancer cell state is dependent on recruitment of Mediator and Cohesin through FOXA and master transcription factors.

  19. FOXA and master transcription factors recruit Mediator and Cohesin to the core transcriptional regulatory circuitry of cancer cells

    Science.gov (United States)

    Fournier, Michèle; Bourriquen, Gaëlle; Lamaze, Fabien C.; Côté, Maxime C.; Fournier, Éric; Joly-Beauparlant, Charles; Caron, Vicky; Gobeil, Stéphane; Droit, Arnaud; Bilodeau, Steve

    2016-01-01

    Controlling the transcriptional program is essential to maintain the identity and the biological functions of a cell. The Mediator and Cohesin complexes have been established as central cofactors controlling the transcriptional program in normal cells. However, the distribution, recruitment and importance of these complexes in cancer cells have not been fully investigated. Here we show that FOXA and master transcription factors are part of the core transcriptional regulatory circuitry of cancer cells and are essential to recruit M ediator and Cohesin. Indeed, Mediator and Cohesin occupied the enhancer and promoter regions of actively transcribed genes and maintained the proliferation and colony forming potential. Through integration of publically available ChIP-Seq datasets, we predicted the core transcriptional regulatory circuitry of each cancer cell. Unexpectedly, for all cells investigated, the pioneer transcription factors FOXA1 and/or FOXA2 were identified in addition to cell-specific master transcription factors. Loss of both types of transcription factors phenocopied the loss of Mediator and Cohesin. Lastly, the master and pioneer transcription factors were essential to recruit Mediator and Cohesin to regulatory regions of actively transcribed genes. Our study proposes that maintenance of the cancer cell state is dependent on recruitment of Mediator and Cohesin through FOXA and master transcription factors. PMID:27739523

  20. CoryneRegNet: An ontology-based data warehouse of corynebacterial transcription factors and regulatory networks

    Directory of Open Access Journals (Sweden)

    Czaja Lisa F

    2006-02-01

    Full Text Available Abstract Background The application of DNA microarray technology in post-genomic analysis of bacterial genome sequences has allowed the generation of huge amounts of data related to regulatory networks. This data along with literature-derived knowledge on regulation of gene expression has opened the way for genome-wide reconstruction of transcriptional regulatory networks. These large-scale reconstructions can be converted into in silico models of bacterial cells that allow a systematic analysis of network behavior in response to changing environmental conditions. Description CoryneRegNet was designed to facilitate the genome-wide reconstruction of transcriptional regulatory networks of corynebacteria relevant in biotechnology and human medicine. During the import and integration process of data derived from experimental studies or literature knowledge CoryneRegNet generates links to genome annotations, to identified transcription factors and to the corresponding cis-regulatory elements. CoryneRegNet is based on a multi-layered, hierarchical and modular concept of transcriptional regulation and was implemented by using the relational database management system MySQL and an ontology-based data structure. Reconstructed regulatory networks can be visualized by using the yFiles JAVA graph library. As an application example of CoryneRegNet, we have reconstructed the global transcriptional regulation of a cellular module involved in SOS and stress response of corynebacteria. Conclusion CoryneRegNet is an ontology-based data warehouse that allows a pertinent data management of regulatory interactions along with the genome-scale reconstruction of transcriptional regulatory networks. These models can further be combined with metabolic networks to build integrated models of cellular function including both metabolism and its transcriptional regulation.

  1. Oxidatively generated base modifications in DNA: Not only carcinogenic risk factor but also regulatory mark?

    Science.gov (United States)

    Seifermann, Marco; Epe, Bernd

    2017-06-01

    The generation of DNA modifications in cells is in most cases accidental and associated with detrimental consequences such as increased mutation rates and an elevated risk of malignant transformation. Accordingly, repair enzymes involved in the removal of the modifications have primarily a protective function. Among the well-established exceptions of this rule are 5-methylcytosine and uracil, which are generated in DNA enzymatically under controlled conditions and fulfill important regulatory functions in DNA as epigenetic marks and in antibody diversification, respectively. More recently, considerable evidence has been obtained that also 8-oxo-7,8-dihydroguanine (8-oxoG), a frequent pro-mutagenic DNA modification generated by endogenous or exogenous reactive oxygen species (ROS), has distinct roles in the regulation of both transcription and signal transduction. Thus, the activation of transcription by the estrogen receptor, NF-κB, MYC and other transcription factors was shown to depend on the presence of 8-oxoG in the promoter regions and its recognition by the DNA repair glycosylase OGG1. The lysine-specific histone demethylase LSD1, which produces H2O2 as a by-product, was indentified as a local generator of 8-oxoG in some of these cases. In addition, a complex of OGG1 with the excised free substrate base was demonstrated to act as a guanine nucleotide exchange factor (GEF) for small GTPases such as Ras, Rac and Rho, thus stimulating signal transduction. The various findings and intriguing novel mechanisms suggested will be described and compared in this review. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Early Pregnancy Factor Enhances the Generation and Function of CD4(+)CD25(+) Regulatory T Cells.

    Science.gov (United States)

    Chen, Quangang; Zhu, Xiaorong; Chen, Renjin; Liu, Jing; Liu, Peng; Hu, Ankang; Wu, Lianlian; Hua, Hui; Yuan, Honghua

    2016-11-01

    The mechanisms of fetal semi-allograft acceptance by the mother's immune system have been the target of many immunological studies. Early pregnancy factor (EPF) is a molecule present in the serum of pregnant mammals soon after conception that has been reported to have immunomodulatory effects. In the present study, we aimed to determine whether immune cells such as CD4(+)CD25(+) regulatory T cells (Tregs) are involved in the suppressive mechanism of EPF. Accordingly, CD4(+)CD25(-) T cells were isolated from spleens of female C57BL/6 mice and stimulated with anti-CD3 antibody, anti-CD28 antibody and IL-2 in the presence or absence of EPF. Flow cytometry was used to analyze the differentiation of CD4(+)CD25(-) T cells to CD4(+)CD25(+) Tregs. We thus found a remarkable rise in the Treg ratio in the EPF-treated cells. Higher mRNA and protein levels of fork head box P3 (Foxp3), a marker of the Treg lineage, were also observed in cells treated with EPF. Furthermore, the effect of EPF on Treg immunosuppressive capacity was evaluated. EPF treatment induced the expression of interleukin-10 and transforming growth factor β1 in Tregs. The suppressive capacity of Tregs was further measured by their capability to inhibit T cell receptor-mediated proliferation of CD4(+)CD25(-) T cells. We thus found that EPF exposure can enhance the immunosuppressive functions of Tregs. Overall, our data suggest that EPF induces the differentiation of Tregs and increases their immunosuppressive activities, which might be an important mechanism to inhibit immune responses during pregnancy.

  3. Crystal structure of the DNA-binding domain of Myelin-gene Regulatory Factor.

    Science.gov (United States)

    Zhen, Xiangkai; Li, Bowen; Hu, Fen; Yan, Shufeng; Meloni, Gabriele; Li, Huiliang; Shi, Ning

    2017-06-16

    Myelin-gene Regulatory Factor (MyRF) is one of the master transcription factors controlling myelin formation and development in oligodendrocytes which is crucial for the powerful brain functions. The N-terminal of MyRF, which contains a proline-rich region and a DNA binding domain (DBD), is auto-cleaved from the ER membrane, and then enters the nucleus to participate in transcription regulation of the myelin genes. Here we report the crystal structure of MyRF DBD. It shows an Ig-fold like architecture which consists of two antiparallel β-sheets with 7 main strands, packing against each other, forming a β-sandwich. Compared to its homolog, Ndt80, MyRF has a smaller and less complex DBD lacking the helices and the big loops outside the core. Structural alignment reveals that MyRF DBD possess less interaction sites with DNA than Ndt80 and may bind only at the major groove of DNA. Moreover, the structure reveals a trimeric assembly, agreeing with the previous report that MyRF DBD functions as a trimer. The mutant that we designed based on the structure disturbed trimer formation, but didn't affect the auto-cleavage reaction. It demonstrates that the activation of self-cleavage reaction of MyRF is independent of the presence of its N-terminal DBD homotrimer. The structure reported here will help to understand the molecular mechanism underlying the important roles of MyRF in myelin formation and development.

  4. Regulatory Factor X (RFX)-mediated transcriptional rewiring of ciliary genes in animals.

    Science.gov (United States)

    Piasecki, Brian P; Burghoorn, Jan; Swoboda, Peter

    2010-07-20

    Cilia were present in the last eukaryotic common ancestor (LECA) and were retained by most organisms spanning all extant eukaryotic lineages, including organisms in the Unikonta (Amoebozoa, fungi, choanoflagellates, and animals), Archaeplastida, Excavata, Chromalveolata, and Rhizaria. In certain animals, including humans, ciliary gene regulation is mediated by Regulatory Factor X (RFX) transcription factors (TFs). RFX TFs bind X-box promoter motifs and thereby positively regulate >50 ciliary genes. Though RFX-mediated ciliary gene regulation has been studied in several bilaterian animals, little is known about the evolutionary conservation of ciliary gene regulation. Here, we explore the evolutionary relationships between RFX TFs and cilia. By sampling the genome sequences of >120 eukaryotic organisms, we show that RFX TFs are exclusively found in unikont organisms (whether ciliated or not), but are completely absent from the genome sequences of all nonunikont organisms (again, whether ciliated or not). Sampling the promoter sequences of 12 highly conserved ciliary genes from 23 diverse unikont and nonunikont organisms further revealed that phylogenetic footprints of X-box promoter motif sequences are found exclusively in ciliary genes of certain animals. Thus, there is no correlation between cilia/ciliary genes and the presence or absence of RFX TFs and X-box promoter motifs in nonanimal unikont and in nonunikont organisms. These data suggest that RFX TFs originated early in the unikont lineage, distinctly after cilia evolved. The evolutionary model that best explains these observations indicates that the transcriptional rewiring of many ciliary genes by RFX TFs occurred early in the animal lineage.

  5. Two New Sterols from Amoora yunnanensis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two new sterols, 3β,7α,16β-trihydroxy-stigmast-5,22-diene 1, 3β,7α,16β-trihydroxy-stigmast-5-ene 2, were isolated together with two known ergosterols, ergosta-5,24(28)-diene-3β,7α-diol, ergosta-5,24(28)-diene-3β,7α,16β-triol from the bark of Amoora yunnanensis (H. L. Li) C. Y. Wu. Their structures were deduced on the basis of spectral data.

  6. Sterols from the Fungus Catathelasma imperiale

    Institute of Scientific and Technical Information of China (English)

    YANG, Sheng-Ping; XU, Jun; YUE, Jian-Min

    2003-01-01

    Eight ergostane-type sterols and three their derivatives (one mono-linoleate and two mono-glucosides) were isolated from the ethyl acetate soluble fraction of the fungus Catathelasma imperiale. Two of them are novel compounds, namely 22E, 24R-ergosta-7,22-diene-3β, 5α-diol-6β-linoleate (1) and 22E, 24R-ergosta-7,22-diene-3β,5β,6α-triol (5) with an uncommon cisfused A/B ring. Structures of these compounds were demonstrated on the basis of their chemical evidences and spectroscopic methods, especially 2D NMR techniques.

  7. A reappraisal of the mechanism by which plant sterols promote neutral sterol loss in mice.

    Directory of Open Access Journals (Sweden)

    Gemma Brufau

    Full Text Available UNLABELLED: Dietary plant sterols (PS reduce serum total and LDL-cholesterol in hyperlipidemic animal models and in humans. This hypocholesterolemic effect is generally ascribed to inhibition of cholesterol absorption. However, whether this effect fully explains the reported strong induction of neutral sterol excretion upon plant sterol feeding is not known. Recent data demonstrate that the intestine directly mediates plasma cholesterol excretion into feces, i.e., without involvement of the hepato-biliary route. OBJECTIVE: Aim of this study was to determine whether stimulation of fecal neutral sterol loss during PS feeding is (partly explained by increased intestinal cholesterol excretion and to assess the role of the cholesterol transporter Abcg5/Abcg8 herein. METHODS AND RESULTS: Wild-type mice were fed a control diet or diets enriched with increasing amounts of PS (1%, 2%, 4% or 8%, wt/wt for two weeks. In addition, Abcg5(-/- mice were fed either control or 8% PS diet. PS feeding resulted in a dose-dependent decrease of fractional cholesterol absorption (∼2-7-fold reduction in wild-type mice and ∼80% reduction in Abcg5(-/- mice. Furthermore, PS feeding led to a strong, dose-independent induction of neutral sterol excretion (3.4-fold in wild-types and 2.7-fold in Abcg5(-/- mice without changes in biliary cholesterol secretion. It was calculated that PS feeding stimulated intestinal cholesterol excretion by ∼500% in wild-type mice and by ∼250% in Abcg5(-/-. CONCLUSIONS: Our data indicate that in mice the cholesterol-lowering effects of PS are to a large extent attributable to stimulation of intestinal, non-bile derived, cholesterol excretion. The Abcg5/Abcg8 heterodimer is involved in facilitating this PS-induced flux of cholesterol.

  8. Tritium Suicide Selection Identifies Proteins Involved in the Uptake and Intracellular Transport of Sterols in Saccharomyces cerevisiae▿

    Science.gov (United States)

    Sullivan, David P.; Georgiev, Alexander; Menon, Anant K.

    2009-01-01

    Sterol transport between the plasma membrane (PM) and the endoplasmic reticulum (ER) occurs by a nonvesicular mechanism that is poorly understood. To identify proteins required for this process, we isolated Saccharomyces cerevisiae mutants with defects in sterol transport. We used Upc2-1 cells that have the ability to take up sterols under aerobic conditions and exploited the observation that intracellular accumulation of exogenously supplied [3H]cholesterol in the form of [3H]cholesteryl ester requires an intact PM-ER sterol transport pathway. Upc2-1 cells were mutagenized using a transposon library, incubated with [3H]cholesterol, and subjected to tritium suicide selection to isolate mutants with a decreased ability to accumulate [3H]cholesterol. Many of the mutants had defects in the expression and trafficking of Aus1 and Pdr11, PM-localized ABC transporters that are required for sterol uptake. Through characterization of one of the mutants, a new role was uncovered for the transcription factor Mot3 in controlling expression of Aus1 and Pdr11. A number of mutants had transposon insertions in the uncharacterized Ydr051c gene, which we now refer to as DET1 (decreased ergosterol transport). These mutants expressed Aus1 and Pdr11 normally but were severely defective in the ability to accumulate exogenously supplied cholesterol. The transport of newly synthesized sterols from the ER to the PM was also defective in det1Δ cells. These data indicate that the cytoplasmic protein encoded by DET1 is involved in intracellular sterol transport. PMID:19060182

  9. 固醇调节元件结合蛋白2在软骨细胞退变过程中的表达%Expression of sterol regulatory element-binding protein-2 in the process of chondrocyte degeneration

    Institute of Scientific and Technical Information of China (English)

    翁鉴; 曾晖; 肖德明; 陶可; 康斌; 梁浩锋

    2015-01-01

    背景:近期研究证实了固醇调节元件结合  蛋白2基因在骨关节炎发生过程中起重要作用,但其具体发病机制尚未完全清楚。目的:通过白细胞介素1β体外诱导关节软骨细胞退变,观察固醇调节元件结合蛋白2在软骨细胞退变过程中的表达变化。方法:体外分离培养C57BL/6J小鼠关节软骨细胞,将第2代软骨细胞随机分为4组:对照组、白细胞介素1β24,48,72 h组。后3组细胞分别以10μg/L白细胞介素1β干预细胞。结果与结论:软骨细胞经白细胞介素1β刺激后呈肥大化表现,软骨细胞活性随白细胞介素1β刺激时间的延长而逐渐降低。与对照组相比,白细胞介素1β24,48,72 h组软骨细胞中固醇调节元件结合蛋白2与固醇调节元件结合蛋白裂解激活蛋白 mRNA表达水平增加,而蛋白聚糖和Ⅱ型胶原 mRNA 表达水平降低。提示白细胞介素1β能抑制软骨细胞增殖和细胞重要基质成分表达,诱导其出现肥大化退行性改变,且在退变的过程中,固醇调节元件结合蛋白2表达逐渐上调,与软骨关键基因的表达呈负向变化关系。%BACKGROUND: Recent studies have demonstrated that sterol regulatory element binding protein-2 (SREBP-2) plays a key role in osteoarthritis, but its exact pathogenesis remains incompletely understood yet. OBJECTIVE:To investigate the expression of SREBP-2 in the process of interleukin-1β-induced articular chondrocyte degenerationin vitro. METHODS: Articular chondrocytes obtained from C57BL/6J mice were culturedin vitro. After the second passage, cels were randomly divided into four groups: control group, and three experimental groups treated with 10 μg/L interleukin-1β for 24, 48 and 72 hours, respectively. RESULTS AND CONCLUSION:The cels became hypertrophic after being stimulated by interleukin-1β, and the staining of colagen X was positive at 72 hours. MTT assay demonstrated that the cel

  10. Reduced fecal sterol excretion in subjects with familial hypoalphalipoproteinemia

    NARCIS (Netherlands)

    El Harchaoui, Karim; Franssen, Remco; Hovingh, G. Kees; Bisoendial, Radjesh J.; Stellaard, Frans; Kuipers, Folkert; Kastelein, John J. P.; Kuivenhoven, Jan Albert; Stroes, Erik S. G.; Groen, Albert K.

    2009-01-01

    BACKGROUND: Fecal bile acid and neutral sterol excretion are the obligate endpoints of the reverse cholesterol transport pathway (RCT). In studies in mice, no evidence was found for a relation between HDL-cholesterol (HDL-c) levels and fecal sterol excretion. In this study, we have evaluated this re

  11. Detailed sterol compositions of two pathogenic rust fungi.

    Science.gov (United States)

    Giner, José-Luis; Zhao, Hui

    2004-08-01

    Teliospores of cedar-apple rust Gymnosporangium juniperi-virginianae were collected from the eastern red cedar Juniperus virginiana, and aeciospores of quince rust G. clavipes were collected from the fruit of English hawthorn Crataegus laevigata. The sterol fractions were separated by HPLC, and their identities were determined by 600 MHz 1H NMR. Twenty-six sterols were isolated from G. juniperi-virginianae and 18 sterols were isolated from G. clavipes. The principal sterol of both fungi was (Z)-stigmasta-7,24(28)-dien-3beta-ol. Other major sterols were (24S)-ergost-7-en-3beta-ol, (24S)-stigmast-7-en-3beta-ol, and (24S)-stigmasta-5,7-dien-3beta-ol. The sterols of the hosts were found to be very different from those of the fungi. The 24-alkyl sterols of the fungi had the 24alpha-configuration, whereas those of the hosts had the 24beta-configuration. Similarities to the sterol composition of the AIDS pneumonia fungus Pneumocystis carinii are discussed.

  12. Composition of plant sterols and stanols in supplemented food products

    Science.gov (United States)

    All fruits, vegetables, grains and other plant materials contain small amounts of plant sterols, which are essential for the function of the biological membranes in living cells. The average human consumption of plant sterols has been estimated to be about 150-350 mg/day and trace amounts of stanol...

  13. STEROLS AS BIOMARKERS IN GYMNODINIUM BREVE DISTRIBUTION IN DINOFLAGELLATES

    Science.gov (United States)

    The sterol composition of marine microalgae has been shown to be a chemotaxonomic property potentially of value in distinguishing members of different algal classes. For example, members of the class Dinophyceae display sterol compositions ranging from as few as two (cholesterol ...

  14. Sterol Ring System Oxidation Pattern in Marine Sponges

    Directory of Open Access Journals (Sweden)

    S. Ramakrishna Rao

    2005-06-01

    Full Text Available Abstract: The marine sponges (Porifera are a unique group of sedentary organisms from which several novel natural products are reported, many of which have useful biological activities. In producing unusual sterols, they occupy a preeminent position among the various groups of organisms. The polar sterols of sponges reported as at the end of the year 2002 number about 250; their ring structure changing a hundred times. The oxidation pattern in the sterol ring system, from the point of view of biogenesis seems to be mainly of four types. Each sponge species is able to produce sterols fitting into one of the four main biogenetic pathways viz., (i 3β-hydroxy-Δ5-sterol pathway, (ii 3β-hydroxy-Δ7-sterol pathway, (iii 3β-hydroxy-Δ5,7-sterol pathway, and (iv 3α-hydroxy sterol pathway.

  15. Regulatory components of the alternative complement pathway in endothelial cell cytoplasm, factor H and factor I, are not packaged in Weibel-Palade bodies.

    Directory of Open Access Journals (Sweden)

    Nancy A Turner

    Full Text Available It was recently reported that factor H, a regulatory component of the alternative complement pathway, is stored with von Willebrand factor (VWF in the Weibel-Palade bodies of endothelial cells. If this were to be the case, it would have therapeutic importance for patients with the atypical hemolytic-uremic syndrome that can be caused either by a heterozygous defect in the factor H gene or by the presence of an autoantibody against factor H. The in vivo Weibel-Palade body secretagogue, des-amino-D-arginine vasopressin (DDAVP, would be expected to increase transiently the circulating factor H levels, in addition to increasing the circulating levels of VWF. We describe experiments demonstrating that factor H is released from endothelial cell cytoplasm without a secondary storage site. These experiments showed that factor H is not stored with VWF in endothelial cell Weibel-Palade bodies, and is not secreted in response in vitro in response to the Weibel-Palade body secretagogue, histamine. Furthermore, the in vivo Weibel-Palade body secretagogue, DDAVP does not increase the circulating factor H levels concomitantly with DDAVP-induced increased VWF. Factor I, a regulatory component of the alternative complement pathway that is functionally related to factor H, is also located in endothelial cell cytoplasm, and is also not present in endothelial cell Weibel-Palade bodies. Our data demonstrate that the factor H and factor I regulatory proteins of the alternative complement pathway are not stored in Weibel-Palade bodies. DDAVP induces the secretion into human plasma of VWF--but not factor H.

  16. Regulatory components of the alternative complement pathway in endothelial cell cytoplasm, factor H and factor I, are not packaged in Weibel-Palade bodies.

    Science.gov (United States)

    Turner, Nancy A; Sartain, Sarah E; Hui, Shiu-Ki; Moake, Joel L

    2015-01-01

    It was recently reported that factor H, a regulatory component of the alternative complement pathway, is stored with von Willebrand factor (VWF) in the Weibel-Palade bodies of endothelial cells. If this were to be the case, it would have therapeutic importance for patients with the atypical hemolytic-uremic syndrome that can be caused either by a heterozygous defect in the factor H gene or by the presence of an autoantibody against factor H. The in vivo Weibel-Palade body secretagogue, des-amino-D-arginine vasopressin (DDAVP), would be expected to increase transiently the circulating factor H levels, in addition to increasing the circulating levels of VWF. We describe experiments demonstrating that factor H is released from endothelial cell cytoplasm without a secondary storage site. These experiments showed that factor H is not stored with VWF in endothelial cell Weibel-Palade bodies, and is not secreted in response in vitro in response to the Weibel-Palade body secretagogue, histamine. Furthermore, the in vivo Weibel-Palade body secretagogue, DDAVP does not increase the circulating factor H levels concomitantly with DDAVP-induced increased VWF. Factor I, a regulatory component of the alternative complement pathway that is functionally related to factor H, is also located in endothelial cell cytoplasm, and is also not present in endothelial cell Weibel-Palade bodies. Our data demonstrate that the factor H and factor I regulatory proteins of the alternative complement pathway are not stored in Weibel-Palade bodies. DDAVP induces the secretion into human plasma of VWF--but not factor H.

  17. Sterols of Pneumocystis carinii hominis organisms isolated from human lungs

    DEFF Research Database (Denmark)

    Kaneshiro, E S; Amit, Z; Chandra, Jan Suresh

    1999-01-01

    The opportunistic pathogen Pneumocystis carinii causes pneumonia (P. carinii pneumonia, or PCP) in immunocompromised individuals such as AIDS patients. Rat-derived P. carinii carinii organisms have distinct sterols which are not synthesized by mammals and not found in other microbes infecting...... mammalian lungs. The dominant sterol present in the organism is cholesterol (which is believed to be scavenged from the host), but other sterols in P. carinii carinii have an alkyl group at C-24 of the sterol side chain (C(28) and C(29) 24-alkylsterols) and a double bond at C-7 of the nucleus. Recently...... in conjunction with analyses of chemically synthesized authentic standards. The sterol composition of isolated P. carinii hominis organisms has yet to be reported. If P. carinii from animal models is to be used for identifying potential drug targets and for developing chemotherapeutic approaches to clear human...

  18. Sterols and Fatty Acids of the Harmful Dinoflagellate Cochlodinium polykrikoides.

    Science.gov (United States)

    Giner, José-Luis; Ceballos, Harriette; Tang, Ying-Zhong; Gobler, Christopher J

    2016-02-01

    Sterol and fatty acid compositions were determined for Cochlodinium polykrikoides, a toxic, bloom-forming dinoflagellate of global significance. The major sterols were dinosterol (40% of total sterols), dihydrodinosterol (32%), and the rare 4α-methyl Δ(8(14)) sterol, amphisterol (23%). A minor sterol, 4α-methylergost-24(28)-enol was also detected (5.0%). The fatty acids had a high proportion of PUFAs (47%), consisting mainly of EPA (20%) and the relatively uncommon octadecapentaenoic acid (18 : 5, 22%). While unlikely to be responsible for toxicity to fish, these lipids may contribute to the deleterious effects of this alga to invertebrates. Copyright © 2016 Verlag Helvetica Chimica Acta AG, Zürich.

  19. Diversity of Sterol Composition in Tunisian Pistacia lentiscus Seed Oil.

    Science.gov (United States)

    Mezni, Faten; Labidi, Arbia; Khouja, Mohamed Larbi; Martine, Lucy; Berdeaux, Olivier; Khaldi, Abdelhamid

    2016-05-01

    Pistacia lentiscus L. seed oil is used in some Mediterranean forest area for culinary and medicinal purposes. In this study, we aim to examine, for the first time, the effect of growing area on sterol content of Pistacia lentiscus seed oil. Fruits were harvested from 13 different sites located in northern and central Tunisia. Gas chromatography-flame-ionization detection (GC-FID) was used to quantify sterols and gas chromatography/mass spectrometry (GC/MS) was used to identify them. The major sterol identified was β-sitosterol with a value ranging from 854.12 to 1224.09 mg/kg of oil, thus making up more than 54% of the total sterols. The other two main sterols were cycloartenol (11%) and 24-methylene-cycloartenol (5%). Statistical results revealed that growing location significantly (P < 0.001) affected phytosterol levels in these oils.

  20. Profiling and Metabolism of Sterols in the Weaver Ant Genus Oecophylla.

    Science.gov (United States)

    Vidkjær, Nanna H; Jensen, Karl-Martin V; Gislum, René; Fomsgaard, Inge S

    2016-01-01

    Sterols are essential to insects because they are vital for many biochemical processes, nevertheless insects cannot synthesize sterols but have to acquire them through their diet. Studies of sterols in ants are sparse and here the sterols of the weaver ant genus Oecophylla are identified for the first time. The sterol profile and the dietary sterols provided to a laboratory Oecophylla longinoda colony were analyzed. Most sterols originated from the diet, except one, which was probably formed via dealkylation in the ants and two sterols of fungal origin, which likely originate from hitherto unidentified endosymbionts responsible for supplying these two compounds. The sterol profile of a wild Oecophylla smaragdina colony was also investigated. Remarkable qualitative similarities were established between the two species despite the differences in diet, species, and origin. This may reflect a common sterol need/aversion in the weaver ants. Additionally, each individual caste of both species displayed unique sterol profiles.

  1. THAP and ATF-2 regulated sterol carrier protein-2 promoter activities in the larval midgut of the yellow fever mosquito, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Rong Peng

    Full Text Available Expression of sterol carrier protein-2 (SCP-2 in Aedes aegypti shows a distinct temporal/spatial pattern throughout the life cycle. In order to identify the transcription factors responsible for the larval temporal/spatial regulation of AeSCP-2 transcription, AeSCP-2 promoter activities were studied in vivo via transient transfection of promoter/reporter gene assays. Regulatory sequences upstream -1.3 kb of the transcription start site of AeSCP-2 were found to be critical for the in vivo temporal/spatial promoter activity. Interestingly, the -1.6 kb promoter sequence efficiently drove the larval midgut-specific siRNA expression, indicating that the -1.6 kb upstream sequence is sufficient for temporal/spatial AeSCP-2 transcriptional activity. Four transcription factors were identified in the midgut nuclear extract from feeding larvae via labeled -1.6/-1.3 kb DNA probe pull-down and proteomic analysis. Co-transfection of the promoter/reporter gene with inducible siRNA expression of each transcription factor was performed to confirm the regulatory function of individual transcription factor on AeSCP-2 transcriptional activities in the larval midgut. The results indicate that two of the identified transcription factors, Thanatos-associated protein (THAP and activating transcription factor-2 (ATF-2, antagonistically control AeSCP-2 transcriptional activity in the midgut of feeding larvae via the regulatory sequences between -1.6 to -1.3 kb 5' upstream of the transcription start site. In vivo expression knockdown of THAP and ATF-2 resulted in significant changes in developmental progression, which may be partially due to their effects on AeSCP-2 expression.

  2. THAP and ATF-2 Regulated Sterol Carrier Protein-2 Promoter Activities in the Larval Midgut of the Yellow Fever Mosquito, Aedes aegypti

    Science.gov (United States)

    Peng, Rong; Fu, Qiang; Hong, Huazhu; Schwaegler, Tyler; Lan, Que

    2012-01-01

    Expression of sterol carrier protein-2 (SCP-2) in Aedes aegypti shows a distinct temporal/spatial pattern throughout the life cycle. In order to identify the transcription factors responsible for the larval temporal/spatial regulation of AeSCP-2 transcription, AeSCP-2 promoter activities were studied in vivo via transient transfection of promoter/reporter gene assays. Regulatory sequences upstream −1.3 kb of the transcription start site of AeSCP-2 were found to be critical for the in vivo temporal/spatial promoter activity. Interestingly, the −1.6 kb promoter sequence efficiently drove the larval midgut-specific siRNA expression, indicating that the −1.6 kb upstream sequence is sufficient for temporal/spatial AeSCP-2 transcriptional activity. Four transcription factors were identified in the midgut nuclear extract from feeding larvae via labeled −1.6/−1.3 kb DNA probe pull-down and proteomic analysis. Co-transfection of the promoter/reporter gene with inducible siRNA expression of each transcription factor was performed to confirm the regulatory function of individual transcription factor on AeSCP-2 transcriptional activities in the larval midgut. The results indicate that two of the identified transcription factors, Thanatos-associated protein (THAP) and activating transcription factor-2 (ATF-2), antagonistically control AeSCP-2 transcriptional activity in the midgut of feeding larvae via the regulatory sequences between −1.6 to −1.3 kb 5′ upstream of the transcription start site. In vivo expression knockdown of THAP and ATF-2 resulted in significant changes in developmental progression, which may be partially due to their effects on AeSCP-2 expression. PMID:23056538

  3. Interferon Regulatory Factor-1 Exerts Inhibitory Effect on Neointimal Formation after Vascular Injury

    Institute of Scientific and Technical Information of China (English)

    Zhen Li; Zhong-gao Wang; Ce Bian; Xiao-dong Chen; Jian-wen Li; Xiu Chen; Bing Han; Gao-feng Hou; Jian Chu; Qi Cui

    2009-01-01

    To investigate the effect of interferon regulatory factors (IRFs) on neointimal formation after vascular injury in the mouse, and its possible mechanism.Methods Vascular injury was induced by polyethylene cuff placement around the left femoral artery of IRF-1-deficient mice and C57BL/6J mice. The mRNA expressions of IRF-1, IRF-2, angiotensin Ⅱ type 2 (AT) receptor, interleukin-1β converting enzyme (ICE), inducible nitric oxide synthase (iNOS) were detected by RT-PCR and immunohistochemical staining.Results Neointimal formation after vascular injury was significantly greater in IRF-1-deficient mice than that in C57BL/6J mice (P<0.05). In contrast, TUNEL-positive nuclei to total nuclei in the neointima and media in vascular smooth muscle cell (VSMC) in the injured artery significantly attenuated in IRF-1-deficient mice compared to C57BL/6J mice (P<0.05). The expressions of AT2 receptor as well as pro-apoptotic genes such as ICE and iNOS in C57BL/6J mice were up-regulated in response to vascular injury, but this upregulation was attenuated in IRF-1-deficient mice.Conclusions Our results suggest that IRF-1 induces VSMC apoptosis and inhibits neointimal formation after vascular injury at least partly due to the upregulation of AT2 receptor, ICE and iNOS expressions. These results indicate that IRF-1 exerts an inhibitory effect on neointimal formation through the induction of apoptosis inVSMCs.

  4. Epithelial nuclear factor-κB signaling promotes lung carcinogenesis via recruitment of regulatory T lymphocytes.

    Science.gov (United States)

    Zaynagetdinov, R; Stathopoulos, G T; Sherrill, T P; Cheng, D-S; McLoed, A G; Ausborn, J A; Polosukhin, V V; Connelly, L; Zhou, W; Fingleton, B; Peebles, R S; Prince, L S; Yull, F E; Blackwell, T S

    2012-06-28

    The mechanisms by which chronic inflammatory lung diseases, particularly chronic obstructive pulmonary disease, confer enhanced risk for lung cancer are not well-defined. To investigate whether nuclear factor (NF)-κB, a key mediator of immune and inflammatory responses, provides an interface between persistent lung inflammation and carcinogenesis, we utilized tetracycline-inducible transgenic mice expressing constitutively active IκB kinase β in airway epithelium (IKTA (IKKβ trans-activated) mice). Intraperitoneal injection of ethyl carbamate (urethane), or 3-methylcholanthrene (MCA) and butylated hydroxytoluene (BHT) was used to induce lung tumorigenesis. Doxycycline-treated IKTA mice developed chronic airway inflammation and markedly increased numbers of lung tumors in response to urethane, even when transgene expression (and therefore epithelial NF-κB activation) was begun after exposure to carcinogen. Studies using a separate tumor initiator/promoter model (MCA+BHT) indicated that NF-κB functions as an independent tumor promoter. Enhanced tumor formation in IKTA mice was preceded by increased proliferation and reduced apoptosis of alveolar epithelium, resulting in increased formation of premalignant lesions. Investigation of inflammatory cells in lungs of IKTA mice revealed a substantial increase in macrophages and lymphocytes, including functional CD4+/CD25+/FoxP3+ regulatory T lymphocytes (Tregs). Importantly, Treg depletion using repetitive injections of anti-CD25 antibodies limited excessive tumor formation in IKTA mice. At 6 weeks following urethane injection, antibody-mediated Treg depletion in IKTA mice reduced the number of premalignant lesions in the lungs in association with an increase in CD8 lymphocytes. Thus, persistent NF-κB signaling in airway epithelium facilitates carcinogenesis by sculpting the immune/inflammatory environment in the lungs.

  5. Vascular endothelial growth factor expression and T-regulatory cells in premenopausal breast cancer.

    Science.gov (United States)

    Recchia, Francesco; Candeloro, Giampiero; Necozione, Stefano; Desideri, Giovambattista; Cesta, Alisia; Recchia, Laura; Rea, Silvio

    2013-04-01

    Estradiol (E2) plays a key role in human reproduction through the induction of vascular endothelial growth factor (VEGF) and T-regulatory cells (T-Regs), which are also important in breast cancer (BC) growth. The primary endpoint of the present study was the investigation of whether E2 suppression, chemotherapy and radiation therapy decreased the levels of VEGF and T-Regs of premenopausal patients with high-risk early BC. The secondary endpoints were toxicity, progression-free survival (PFS) and overall survival (OS). Between April 2003 and July 2008, 100 premenopausal women with early, high-risk BC were entered into the study. The characteristics of the patients were as follows: median age, 43 years (range, 26-45); median number of positive axillary nodes, 3.3; median Ki-67, 33%. Plasma E2, VEGF and T-Reg were measured at baseline and every year. Treatment comprised luteneizing hormone-releasing hormone (LH-RH) analogue, tailored chemotherapy, radiation therapy and hormonal therapy in oestrogen receptor-positive (ER(+)) tumours. At 4 years, a statistically significant decrease in E2, VEGF and T-Reg levels was observed; the PFS and OS rates were 94 and 98%, respectively. Hot flushes and G1 osteopenia occurred following LH-RH analogue administration, while no unexpected toxicity was observed following chemotherapy. E2 deprivation with an LH-RH analogue, tailored chemotherapy, radiation therapy and hormonal therapy in ER(+) tumours decreased plasma VEGF levels and T-Regs numbers in premenopausal high-risk ER(+) and ER- BC patients. In addition, a favorable impact on PFS and OS was observed.

  6. Sustained activation of interferon regulatory factor 3 during infection by paramyxoviruses requires MDA5.

    Science.gov (United States)

    Grandvaux, Nathalie; Guan, Xiaochun; Yoboua, Fabrice; Zucchini, Nicolas; Fink, Karin; Doyon, Priscilla; Martin, Lydie; Servant, Marc J; Chartier, Stéfany

    2014-01-01

    Retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) are the main cytosolic sensors of single-stranded RNA viruses, including paramyxoviruses, and are required to initiate a quick and robust innate antiviral response. Despite different ligand-binding properties, the consensus view is that RIG-I and MDA5 trigger common signal(s) to activate interferon regulatory factor 3 (IRF-3) and NF-κB, and downstream antiviral and proinflammatory cytokine expression. Here, we performed a thorough analysis of the temporal involvement of RIG-I and MDA5 in the regulation of IRF-3 during respiratory syncytial virus (RSV) infection. Based on specific RNA interference-mediated knockdown of RIG-I and MDA5 in A549 cells, we confirmed that RIG-I is critical for the initiation of IRF-3 phosphorylation, dimerization and downstream gene expression. On the other hand, our experiments yielded the first evidence that knockdown of MDA5 leads to early ubiquitination and proteasomal degradation of active IRF-3. Conversely, ectopic expression of MDA5 prolonged RIG-I-induced IRF-3 activation. Altogether, we provide novel mechanistic insight into the temporal involvement of RIG-I and MDA5 in the innate antiviral response. While RIG-I is essential for initial IRF-3 activation, engagement of induced MDA5 is essential to prevent early degradation of IRF-3, thereby sustaining IRF-3-dependent antiviral gene expression. MDA5 plays a similar role during Sendai virus infection suggesting that this model is not restricted to RSV amongst paramyxoviruses.

  7. ATP-binding cassette transporters and sterol O-acyltransferases interact at membrane microdomains to modulate sterol uptake and esterification.

    Science.gov (United States)

    Gulati, Sonia; Balderes, Dina; Kim, Christine; Guo, Zhongmin A; Wilcox, Lisa; Area-Gomez, Estela; Snider, Jamie; Wolinski, Heimo; Stagljar, Igor; Granato, Juliana T; Ruggles, Kelly V; DeGiorgis, Joseph A; Kohlwein, Sepp D; Schon, Eric A; Sturley, Stephen L

    2015-11-01

    A key component of eukaryotic lipid homeostasis is the esterification of sterols with fatty acids by sterol O-acyltransferases (SOATs). The esterification reactions are allosterically activated by their sterol substrates, the majority of which accumulate at the plasma membrane. We demonstrate that in yeast, sterol transport from the plasma membrane to the site of esterification is associated with the physical interaction of the major SOAT, acyl-coenzyme A:cholesterol acyltransferase (ACAT)-related enzyme (Are)2p, with 2 plasma membrane ATP-binding cassette (ABC) transporters: Aus1p and Pdr11p. Are2p, Aus1p, and Pdr11p, unlike the minor acyltransferase, Are1p, colocalize to sterol and sphingolipid-enriched, detergent-resistant microdomains (DRMs). Deletion of either ABC transporter results in Are2p relocalization to detergent-soluble membrane domains and a significant decrease (53-36%) in esterification of exogenous sterol. Similarly, in murine tissues, the SOAT1/Acat1 enzyme and activity localize to DRMs. This subcellular localization is diminished upon deletion of murine ABC transporters, such as Abcg1, which itself is DRM associated. We propose that the close proximity of sterol esterification and transport proteins to each other combined with their residence in lipid-enriched membrane microdomains facilitates rapid, high-capacity sterol transport and esterification, obviating any requirement for soluble intermediary proteins.

  8. Fast and accurate method for total 4-desmethyl sterol(s) content in spreads, fat-blends and raw materials

    NARCIS (Netherlands)

    Duchateau, G.S.M.J.E.; Bauer-Plank, C.G.; Louter, A.J.H.; Ham, M. van der; Boerma, J.A.; Rooijen, J.J.M. van; Zandbelt, P.A.

    2002-01-01

    Plant sterols are added as their FA esters to vegetable oil table spreads at levels of approximately 8% as a means to reduce blood cholesterol levels. A new chromatographic method was designed to quantify quickly the level of plant sterol FA esters in incoming (raw) materials and to monitor their

  9. Construction of pancreatic cancer double-factor regulatory network based on chip data on the transcriptional level.

    Science.gov (United States)

    Zhao, Li-Li; Zhang, Tong; Liu, Bing-Rong; Liu, Tie-Fu; Tao, Na; Zhuang, Li-Wei

    2014-05-01

    Transcription factor (TF) and microRNA (miRNA) have been discovered playing crucial roles in cancer development. However, the effect of TFs and miRNAs in pancreatic cancer pathogenesis remains vague. We attempted to reveal the possible mechanism of pancreatic cancer based on transcription level. Using GSE16515 datasets downloaded from gene expression omnibus database, we first identified the differentially expressed genes (DEGs) in pancreatic cancer by the limma package in R. Then the DEGs were mapped into DAVID to conduct the kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. TFs and miRNAs that DEGs significantly enriched were identified by Fisher's test, and then the pancreatic cancer double-factor regulatory network was constructed. In our study, total 1117 DEGs were identified and they significantly enriched in 4 KEGG pathways. A double-factor regulatory network was established, including 29 DEGs, 24 TFs, 25 miRNAs. In the network, LAMC2, BRIP1 and miR155 were identified which may be involved in pancreatic cancer development. In conclusion, the double-factor regulatory network was found to play an important role in pancreatic cancer progression and our results shed new light on the molecular mechanism of pancreatic cancer.

  10. Restricted maternal nutrition alters myogenic regulatory factor expression in satellite cells of ovine offspring.

    Science.gov (United States)

    Raja, J S; Hoffman, M L; Govoni, K E; Zinn, S A; Reed, S A

    2016-07-01

    Poor maternal nutrition inhibits muscle development and postnatal muscle growth. Satellite cells are myogenic precursor cells that contribute to postnatal muscle growth, and their activity can be evaluated by the expression of several transcription factors. Paired-box (Pax)7 is expressed in quiescent and active satellite cells. MyoD is expressed in activated and proliferating satellite cells and myogenin is expressed in terminally differentiating cells. Disruption in the expression pattern or timing of expression of myogenic regulatory factors negatively affects muscle development and growth. We hypothesized that poor maternal nutrition during gestation would alter the in vitro temporal expression of MyoD and myogenin in satellite cells from offspring at birth and 3 months of age. Ewes were fed 100% or 60% of NRC requirements from day 31±1.3 of gestation. Lambs from control-fed (CON) or restricted-fed (RES) ewes were euthanized within 24 h of birth (birth; n=5) or were fed a control diet until 3 months of age (n=5). Satellite cells isolated from the semitendinosus muscle were used for gene expression analysis or cultured for 24, 48 or 72 h and immunostained for Pax7, MyoD or myogenin. Fusion index was calculated from a subset of cells allowed to differentiate. Compared with CON, temporal expression of MyoD and myogenin was altered in cultured satellite cells isolated from RES lambs at birth. The percent of cells expressing MyoD was greater in RES than CON (P=0.03) after 24 h in culture. After 48 h of culture, there was a greater percent of cells expressing myogenin in RES compared with CON (P0.05). In satellite cells from RES lambs at 3 months of age, the percent of cells expressing MyoD and myogenin were greater than CON after 72 h in culture (Psatellite cells of the offspring, which may reduce the pool of myoblasts, decrease myoblast fusion and contribute to the poor postnatal muscle growth previously observed in these animals.

  11. Characterization of the regulatory mechanisms of activating transcription factor 3 by hypertrophic stimuli in rat cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Elina Koivisto

    Full Text Available AIMS: Activating transcription factor 3 (ATF3 is a stress-activated immediate early gene suggested to have both detrimental and cardioprotective role in the heart. Here we studied the mechanisms of ATF3 activation by hypertrophic stimuli and ATF3 downstream targets in rat cardiomyocytes. METHODS AND RESULTS: When neonatal rat cardiomyocytes were exposed to endothelin-1 (ET-1, 100 nM and mechanical stretching in vitro, maximal increase in ATF3 expression occurred at 1 hour. Inhibition of extracellular signal-regulated kinase (ERK by PD98059 decreased ET-1- and stretch-induced increase of ATF3 protein but not ATF3 mRNA levels, whereas protein kinase A (PKA inhibitor H89 attenuated both ATF3 mRNA transcription and protein expression in response to ET-1 and stretch. To characterize further the regulatory mechanisms upstream of ATF3, p38 mitogen-activated protein kinase (MAPK signaling was investigated using a gain-of-function approach. Adenoviral overexpression of p38α, but not p38β, increased ATF3 mRNA and protein levels as well as DNA binding activity. To investigate the role of ATF3 in hypertrophic process, we overexpressed ATF3 by adenovirus-mediated gene transfer. In vitro, ATF3 gene delivery attenuated the mRNA transcription of interleukin-6 (IL-6 and plasminogen activator inhibitor-1 (PAI-1, and enhanced nuclear factor-κB (NF-κB and Nkx-2.5 DNA binding activities. Reduced PAI-1 expression was also detected in vivo in adult rat heart by direct intramyocardial adenovirus-mediated ATF3 gene delivery. CONCLUSIONS: These data demonstrate that ATF3 activation by ET-1 and mechanical stretch is partly mediated through ERK and cAMP-PKA pathways, whereas p38 MAPK pathway is involved in ATF3 activation exclusively through p38α isoform. ATF3 activation caused induction of modulators of the inflammatory response NF-κB and Nkx-2.5, as well as attenuation of pro-fibrotic and pro-inflammatory proteins IL-6 and PAI-1, suggesting cardioprotective role

  12. Comparison of Enzymatic Hydrolysis and Acid Hydrolysis of Sterol Glycosides from Foods Rich in Δ(7)-Sterols.

    Science.gov (United States)

    Münger, Linda H; Jutzi, Sabrina; Lampi, Anna-Maija; Nyström, Laura

    2015-08-01

    In this study, we present the difference in sterol composition of extracted steryl glycosides (SG) hydrolyzed by either enzymatic or acid hydrolysis. SG were analyzed from foods belonging to the plant families Cucurbitaceae (melon and pumpkin seeds) and Amaranthaceae (amaranth and beetroot), both of which are dominated by Δ(7)-sterols. Released sterols were quantified by gas chromatography with a flame ionization detector (GC-FID) and identified using gas chromatography/mass spectrometry (GC-MS). All Δ(7)-sterols identified (Δ(7)-stigmastenyl, spinasteryl, Δ(7)-campesteryl, Δ(7)-avenasteryl, poriferasta-7,25-dienyl and poriferasta-7,22,25-trienyl glucoside) underwent isomerization under acidic conditions and high temperature. Sterols with an ethylidene or methylidene side chain were found to form multiple artifacts. The artifact sterols coeluted with residues of incompletely isomerized Δ(7)-sterols, or Δ(5)-sterols if present, and could be identified as Δ(8(14))-sterols on the basis of relative retention time, and their MS spectra as trimethylsilyl (TMS) and acetate derivatives. For instance, SG from melon were composed of 66% Δ(7)-stigmastenol when enzymatic hydrolysis was performed, whereas with acid hydrolysis only 8% of Δ(7)-stigmastenol was determined. The artifact of Δ(7)-stigmastenol coeluted with residual non-isomerized spinasterol, demonstrating the high risk of misinterpretation of compositional data obtained after acid hydrolysis. Therefore, the accurate composition of SG from foods containing sterols with a double bond at C-7 can only be obtained by enzymatic hydrolysis or by direct analysis of the intact SG.

  13. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase.

    Science.gov (United States)

    Kaneshiro, Edna S; Johnston, Laura Q; Nkinin, Stephenson W; Romero, Becky I; Giner, José-Luis

    2015-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The Pneumocystis carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions, whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild-type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography and proton nuclear magnetic resonance spectroscopy ((1)H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ(24(28)) -sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii.

  14. The role of Smad Ubiquitin Regulatory Factor-1: SMURF1 in the differentiation 3T3-L1

    OpenAIRE

    Muñiz Diego, María del Carmen

    2013-01-01

    The Smad Ubiquitin Regulatory Factor-1: SMURF1 is an E3 ligase. This E3 ligase has been linked to several important biological pathways, including the bone morphogenetic protein pathway, the non-canonical Wnt pathway and the mitogen-activated protein kinase pathway. Multiple functions of Smurf1 have been discovered in cell growth and morphogenesis, cell migration, cell polarity and autophagy. Previous studies, in 2003, have demonstrated that overexpression of Smurf1 induces proteasomal degrad...

  15. Vpu Mediates Depletion of Interferon Regulatory Factor 3 during HIV Infection by a Lysosome-Dependent Mechanism

    OpenAIRE

    Doehle, Brian P.; Chang, Kristina; Rustagi, Arjun; McNevin, John; McElrath, M. Juliana; Gale, Michael

    2012-01-01

    HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon ...

  16. Sterol Composition in Infant Formulas and Estimated Intake.

    Science.gov (United States)

    Claumarchirant, Lorena; Matencio, Esther; Sanchez-Siles, Luis Manuel; Alegría, Amparo; Lagarda, María Jesús

    2015-08-19

    Sterol contents in infant formulas (IFs) from the European market were determined, and their intakes by infants between 0 and 6 months were evaluated. Total animal sterols (mg/100 mL) ranged from 1.71 to 5.46, cholesterol being the main animal sterol (1.46-5.1). In general, cholesterol and desmosterol were lower than the human milk (HM) values indicated by other authors. Total plant sterol (mg/100 mL) ranged from 3.1 to 5.0. β-Sitosterol, the most abundant phytosterol, ranged from 1.82 to 3.01, followed by campesterol (0.72-1.15), stigmasterol (0.27-0.53), and brassicasterol (0.14-0.28). Cholesterol intake (mg/day) ranged from 9 to 51 and plant sterol intake (mg/day) from 19 to 50. The sterol profile of IFs is highly dependent on the type and quantity of fats used in their formula. The use of bovine milk fat and milk fat globule membrane in the IFs can approximate the profile of animal sterols to those found in HM, though cholesterol intakes in breastfed infants are still higher than in formula-fed infants.

  17. Sterols of a contemporary lacustrine sediment. [in English postglacial lake

    Science.gov (United States)

    Gaskell, S. J.; Eglinton, G.

    1976-01-01

    Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

  18. Sterols of a contemporary lacustrine sediment. [in English postglacial lake

    Science.gov (United States)

    Gaskell, S. J.; Eglinton, G.

    1976-01-01

    Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

  19. Sterol composition from inflorescences of Hieracium pilosella L.

    Directory of Open Access Journals (Sweden)

    Tadeusz Krzaczek

    2011-01-01

    Full Text Available The fraction of sterol acetates from the inflorescences of Hieracium pilosella has been isolated in the typical way from petroleum ether extract. By means of the weight method the total amount of sterols was determined (0.2659%. The mixtures of sterol acetates and free sterols were investigated using GC-MS techniques. The occurrence of about 18 sterols has been observed. Cholesterol, cholest-8(14-en-3b-ol, cholesta-5.7-dien-3b-ol, cholest-7-en-3b-ol, ergosta-5.24-dien-3b-ol, campesterol, stigmasterol, b-sitosterol, fucosterol, 5a-stigmast-7-en-3a-ol were identified. The probable structures of lophenol, isofucosterol, 5a-stigmasta-7.24-dien-3b-ol, lanosta-9(11.24-dien-3b-ol and 24-ethylidene lophenol were stated on the basis of literature data. The last 4 sterols occur in a vestigial quantity, which made its identification impossible. Sitos erol and cholesterol are remarkably dominating sterols in the fraction.

  20. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    Science.gov (United States)

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF MS) to resolve and identify the molecular species of all four sterol lipid classes from Arabidopsis thaliana. Free sterols were derivatized with chlorobetainyl chloride. Sterol esters, sterol glycosides, and acylated sterol glycosides were ionized as ammonium adducts. Quantification of molecular species was achieved in the positive mode after fragmentation in the presence of internal standards. The amounts of sterol lipids quantified by Q-TOF MS/MS were validated by comparison with results obtained with TLC/GC. Quantification of sterol lipids from leaves and roots of phosphate-deprived A. thaliana plants revealed changes in the amounts and molecular species composition. The Q-TOF method is far more sensitive than GC or HPLC. Therefore, Q-TOF MS/MS provides a comprehensive strategy for sterol lipid quantification that can be adapted to other tandem mass spectrometers. PMID:21382968

  1. Neutral Sterols of Cephalic Glands of Stingless Bees and Their Correlation with Sterols from Pollen

    Directory of Open Access Journals (Sweden)

    Maria Juliana Ferreira-Caliman

    2012-01-01

    de novo and, thus, all phytophagous insects depend on an exogenous source of sterols for growth, development, and reproduction. The sterol requirements of social bees are not fully known due to the fact that there is no well-defined diet available throughout the year with regard to floral resources. Our study aimed to characterize the sterols present in pollen stored in Melipona marginata and Melipona scutellaris colonies, as well as evaluating their presence in the mandibular, hypopharyngeal, and cephalic salivary gland secretions. We analyzed the chemical composition of pollen stored in the colonies and the composition of the cephalic glands of workers in three adult functional phases (newly emerged, nurses, and foragers by gas chromatography and mass spectrometry. The results showed that the pollen analyzed contained campesterol, stigmasterol, sitosterol, isofucosterol, lanosterol, and small amounts of cholesterol. The glands showed the same compounds found in the pollen analyzed, except lanosterol that was not found in M. scutellaris glands. Surprisingly, cholesterol was found in some glands with relative ratios greater than those found in pollen.

  2. Interaction of the P-Glycoprotein Multidrug Transporter with Sterols.

    Science.gov (United States)

    Clay, Adam T; Lu, Peihua; Sharom, Frances J

    2015-11-01

    The ABC transporter P-glycoprotein (Pgp, ABCB1) actively exports structurally diverse substrates from within the lipid bilayer, leading to multidrug resistance. Many aspects of Pgp function are altered by the phospholipid environment, but its interactions with sterols remain enigmatic. In this work, the functional interaction between purified Pgp and various sterols was investigated in detergent solution and proteoliposomes. Fluorescence studies showed that dehydroergosterol, cholestatrienol, and NBD-cholesterol interact intimately with Pgp, resulting in both quenching of protein Trp fluorescence and enhancement of sterol fluorescence. Kd values indicated binding affinities in the range of 3-9 μM. Collisional quenching experiments showed that Pgp-bound NBD-cholesterol was protected from the external milieu, resonance energy transfer was observed between Pgp Trp residues and the sterol, and the fluorescence emission of bound sterol was enhanced. These observations suggested an intimate interaction of bound sterols with the transporter at a protected nonpolar site. Cholesterol hemisuccinate altered the thermal unfolding of Pgp and greatly stabilized its basal ATPase activity in both a detergent solution and reconstituted proteoliposomes of certain phospholipids. Other sterols, including dehydroergosterol, did not stabilize the basal ATPase activity of detergent-solubilized Pgp, which suggests that this is not a generalized sterol effect. The phospholipid composition and cholesterol hemisuccinate content of Pgp proteoliposomes altered the basal ATPase and drug transport cycles differently. Sterols may interact with Pgp and modulate its structure and function by occupying part of the drug-binding pocket or by binding to putative consensus cholesterol-binding (CRAC/CARC) motifs located within the transmembrane domains.

  3. Paleoproterozoic sterol biosynthesis and the rise of oxygen

    Science.gov (United States)

    Gold, David A.; Caron, Abigail; Fournier, Gregory P.; Summons, Roger E.

    2017-03-01

    Natural products preserved in the geological record can function as ‘molecular fossils’, providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids. Complex sterols with modified side chains are unique to eukaryotes, although simpler sterols can also be synthesized by a few bacteria. Sterol biosynthesis is an oxygen-intensive process; thus, the presence of complex steranes in ancient rocks not only signals the presence of eukaryotes, but also aerobic metabolic processes. In 1999, steranes were reported in 2.7 billion year (Gyr)-old rocks from the Pilbara Craton in Australia, suggesting a long delay between photosynthetic oxygen production and its accumulation in the atmosphere (also known as the Great Oxidation Event) 2.45-2.32 Gyr ago. However, the recent reappraisal and rejection of these steranes as contaminants pushes the oldest reported steranes forward to around 1.64 Gyr ago (ref. 6). Here we use a molecular clock approach to improve constraints on the evolution of sterol biosynthesis. We infer that stem eukaryotes shared functionally modern sterol biosynthesis genes with bacteria via horizontal gene transfer. Comparing multiple molecular clock analyses, we find that the maximum marginal probability for the divergence time of bacterial and eukaryal sterol biosynthesis genes is around 2.31 Gyr ago, concurrent with the most recent geochemical evidence for the Great Oxidation Event. Our results therefore indicate that simple sterol biosynthesis existed well before the diversification of living eukaryotes, substantially predating the oldest detected sterane biomarkers (approximately 1.64 Gyr ago), and furthermore, that the evolutionary history of sterol biosynthesis is tied to the first widespread availability of molecular oxygen in the ocean-atmosphere system.

  4. Paleoproterozoic sterol biosynthesis and the rise of oxygen.

    Science.gov (United States)

    Gold, David A; Caron, Abigail; Fournier, Gregory P; Summons, Roger E

    2017-03-16

    Natural products preserved in the geological record can function as 'molecular fossils', providing insight into organisms and physiologies that existed in the deep past. One important group of molecular fossils is the steroidal hydrocarbons (steranes), which are the diagenetic remains of sterol lipids. Complex sterols with modified side chains are unique to eukaryotes, although simpler sterols can also be synthesized by a few bacteria. Sterol biosynthesis is an oxygen-intensive process; thus, the presence of complex steranes in ancient rocks not only signals the presence of eukaryotes, but also aerobic metabolic processes. In 1999, steranes were reported in 2.7 billion year (Gyr)-old rocks from the Pilbara Craton in Australia, suggesting a long delay between photosynthetic oxygen production and its accumulation in the atmosphere (also known as the Great Oxidation Event) 2.45-2.32 Gyr ago. However, the recent reappraisal and rejection of these steranes as contaminants pushes the oldest reported steranes forward to around 1.64 Gyr ago (ref. 6). Here we use a molecular clock approach to improve constraints on the evolution of sterol biosynthesis. We infer that stem eukaryotes shared functionally modern sterol biosynthesis genes with bacteria via horizontal gene transfer. Comparing multiple molecular clock analyses, we find that the maximum marginal probability for the divergence time of bacterial and eukaryal sterol biosynthesis genes is around 2.31 Gyr ago, concurrent with the most recent geochemical evidence for the Great Oxidation Event. Our results therefore indicate that simple sterol biosynthesis existed well before the diversification of living eukaryotes, substantially predating the oldest detected sterane biomarkers (approximately 1.64 Gyr ago), and furthermore, that the evolutionary history of sterol biosynthesis is tied to the first widespread availability of molecular oxygen in the ocean-atmosphere system.

  5. Sterol composition of the Adriatic Sea algae Ulva lactuca, Codium dichotomum, Cystoseira adriatica and Fucus virsoides

    Directory of Open Access Journals (Sweden)

    RADOMIR KAPETANOVIC

    2005-12-01

    Full Text Available The sterol composition of two green algae and two brown algae from the South Adriatic was determined. In the green alga Ulva lactuca, the principal sterols were cholesterol and isofucosterol. In the brown alga Cystoseira adriatica, the main sterols were cholesterol and stigmast-5-en-3ß-ol, while the characteristic sterol of the brown algae, fucosterol, was found only in low concentration. The sterol fractions of the green alga Codium dichotomum and the brown alga Fucus virsoides contained practically only one sterol each, comprising more than 90 % of the total sterols (clerosterol in the former and fucosterol in the latter.

  6. Regulatory Lymphocytes Are Key Factors in MHC-Independent Resistance to EAE

    Directory of Open Access Journals (Sweden)

    Nieves Marín

    2014-01-01

    Full Text Available Background and Objectives. Resistant and susceptible mouse strains to experimental autoimmune encephalomyelitis (EAE, an inducible demyelinating experimental disease serving as animal model for multiple sclerosis, have been described. We aimed to explore MHC-independent mechanisms inducing resistance to EAE. Methods. For EAE induction, female C57BL/6 (susceptible strain and CD1 (resistant outbred strain showing heterogeneous MHC antigens mice were immunized with the 35–55 peptide of myelin oligodendrocyte glycoprotein (MOG35−55. We studied T cell proliferation, regulatory and effector cell subpopulations, intracellular and serum cytokine patterns, and titers of anti-MOG serum antibodies. Results. Upon immunization with MOG35−55, T lymphocytes from susceptible mice but not that of resistant strain were capable of proliferating when stimulated with MOG35−55. Accordingly, resistant mice experienced a rise in regulatory B cells (P=0.001 and, to a lower extent, in regulatory T cells (P=0.02 compared with C57BL/6 susceptible mice. As a consequence, MOG35−55-immunized C57BL/6 mice showed higher percentages of CD4+ T cells producing both IFN-gamma (P=0.02 and IL-17 (P=0.009 and higher serum levels of IL-17 (P=0.04 than resistant mice. Conclusions. Expansion of regulatory B and T cells contributes to the induction of resistance to EAE by an MHC-independent mechanism.

  7. Regulatory Lymphocytes Are Key Factors in MHC-Independent Resistance to EAE

    Science.gov (United States)

    Marín, Nieves; Mecha, Miriam; Espejo, Carmen; Mestre, Leyre; Eixarch, Herena; Montalban, Xavier; Álvarez-Cermeño, José C.; Guaza, Carmen; Villar, Luisa M.

    2014-01-01

    Background and Objectives. Resistant and susceptible mouse strains to experimental autoimmune encephalomyelitis (EAE), an inducible demyelinating experimental disease serving as animal model for multiple sclerosis, have been described. We aimed to explore MHC-independent mechanisms inducing resistance to EAE. Methods. For EAE induction, female C57BL/6 (susceptible strain) and CD1 (resistant outbred strain showing heterogeneous MHC antigens) mice were immunized with the 35–55 peptide of myelin oligodendrocyte glycoprotein (MOG35−55). We studied T cell proliferation, regulatory and effector cell subpopulations, intracellular and serum cytokine patterns, and titers of anti-MOG serum antibodies. Results. Upon immunization with MOG35−55, T lymphocytes from susceptible mice but not that of resistant strain were capable of proliferating when stimulated with MOG35−55. Accordingly, resistant mice experienced a rise in regulatory B cells (P = 0.001) and, to a lower extent, in regulatory T cells (P = 0.02) compared with C57BL/6 susceptible mice. As a consequence, MOG35−55-immunized C57BL/6 mice showed higher percentages of CD4+ T cells producing both IFN-gamma (P = 0.02) and IL-17 (P = 0.009) and higher serum levels of IL-17 (P = 0.04) than resistant mice. Conclusions. Expansion of regulatory B and T cells contributes to the induction of resistance to EAE by an MHC-independent mechanism. PMID:24868560

  8. Boolean Modelling Reveals New Regulatory Connections between Transcription Factors Orchestrating the Development of the Ventral Spinal Cord

    Science.gov (United States)

    Lovrics, Anna; Gao, Yu; Juhász, Bianka; Bock, István; Byrne, Helen M.; Dinnyés, András; Kovács, Krisztián A.

    2014-01-01

    We have assembled a network of cell-fate determining transcription factors that play a key role in the specification of the ventral neuronal subtypes of the spinal cord on the basis of published transcriptional interactions. Asynchronous Boolean modelling of the network was used to compare simulation results with reported experimental observations. Such comparison highlighted the need to include additional regulatory connections in order to obtain the fixed point attractors of the model associated with the five known progenitor cell types located in the ventral spinal cord. The revised gene regulatory network reproduced previously observed cell state switches between progenitor cells observed in knock-out animal models or in experiments where the transcription factors were overexpressed. Furthermore the network predicted the inhibition of Irx3 by Nkx2.2 and this prediction was tested experimentally. Our results provide evidence for the existence of an as yet undescribed inhibitory connection which could potentially have significance beyond the ventral spinal cord. The work presented in this paper demonstrates the strength of Boolean modelling for identifying gene regulatory networks. PMID:25398016

  9. Boolean modelling reveals new regulatory connections between transcription factors orchestrating the development of the ventral spinal cord.

    KAUST Repository

    Lovrics, Anna

    2014-11-14

    We have assembled a network of cell-fate determining transcription factors that play a key role in the specification of the ventral neuronal subtypes of the spinal cord on the basis of published transcriptional interactions. Asynchronous Boolean modelling of the network was used to compare simulation results with reported experimental observations. Such comparison highlighted the need to include additional regulatory connections in order to obtain the fixed point attractors of the model associated with the five known progenitor cell types located in the ventral spinal cord. The revised gene regulatory network reproduced previously observed cell state switches between progenitor cells observed in knock-out animal models or in experiments where the transcription factors were overexpressed. Furthermore the network predicted the inhibition of Irx3 by Nkx2.2 and this prediction was tested experimentally. Our results provide evidence for the existence of an as yet undescribed inhibitory connection which could potentially have significance beyond the ventral spinal cord. The work presented in this paper demonstrates the strength of Boolean modelling for identifying gene regulatory networks.

  10. Activation of Vago by interferon regulatory factor (IRF) suggests an interferon system-like antiviral mechanism in shrimp.

    Science.gov (United States)

    Li, Chaozheng; Li, Haoyang; Chen, Yixiao; Chen, Yonggui; Wang, Sheng; Weng, Shao-Ping; Xu, Xiaopeng; He, Jianguo

    2015-10-13

    There is a debate on whether invertebrates possess an antiviral immunity similar to the interferon (IFN) system of vertebrates. The Vago gene from arthropods encodes a viral-activated secreted peptide that restricts virus infection through activating the JAK-STAT pathway and is considered to be a cytokine functionally similar to IFN. In this study, the first crustacean IFN regulatory factor (IRF)-like gene was identified in Pacific white shrimp, Litopenaeus vannamei. The L. vannamei IRF showed similar protein nature to mammalian IRFs and could be activated during virus infection. As a transcriptional regulatory factor, L. vannamei IRF could activate the IFN-stimulated response element (ISRE)-containing promoter to regulate the expression of mammalian type I IFNs and initiate an antiviral state in mammalian cells. More importantly, IRF could bind the 5'-untranslated region of L. vannamei Vago4 gene and activate its transcription, suggesting that shrimp Vago may be induced in a similar manner to that of IFNs and supporting the opinion that Vago might function as an IFN-like molecule in invertebrates. These suggested that shrimp might possess an IRF-Vago-JAK/STAT regulatory axis, which is similar to the IRF-IFN-JAK/STAT axis of vertebrates, indicating that invertebrates might possess an IFN system-like antiviral mechanism.

  11. Global characterization of interferon regulatory factor (IRF genes in vertebrates: Glimpse of the diversification in evolution

    Directory of Open Access Journals (Sweden)

    Xu Zhen

    2010-05-01

    Full Text Available Abstract Background Interferon regulatory factors (IRFs, which can be identified based on a unique helix-turn-helix DNA-binding domain (DBD are a large family of transcription factors involved in host immune response, haemotopoietic differentiation and immunomodulation. Despite the identification of ten IRF family members in mammals, and some recent effort to identify these members in fish, relatively little is known in the composition of these members in other classes of vertebrates, and the evolution and probably the origin of the IRF family have not been investigated in vertebrates. Results Genome data mining has been performed to identify any possible IRF family members in human, mouse, dog, chicken, anole lizard, frog, and some teleost fish, mainly zebrafish and stickleback, and also in non-vertebrate deuterostomes including the hemichordate, cephalochordate, urochordate and echinoderm. In vertebrates, all ten IRF family members, i.e. IRF-1 to IRF-10 were identified, with two genes of IRF-4 and IRF-6 identified in fish and frog, respectively, except that in zebrafish exist three IRF-4 genes. Surprisingly, an additional member in the IRF family, IRF-11 was found in teleost fish. A range of two to ten IRF-like genes were detected in the non-vertebrate deuterostomes, and they had little similarity to those IRF family members in vertebrates as revealed in genomic structure and in phylogenetic analysis. However, the ten IRF family members, IRF-1 to IRF-10 showed certain degrees of conservation in terms of genomic structure and gene synteny. In particular, IRF-1, IRF-2, IRF-6, IRF-8 are quite conserved in their genomic structure in all vertebrates, and to a less degree, some IRF family members, such as IRF-5 and IRF-9 are comparable in the structure. Synteny analysis revealed that the gene loci for the ten IRF family members in vertebrates were also quite conservative, but in zebrafish conserved genes were distributed in a much longer distance in

  12. Global characterization of interferon regulatory factor (IRF) genes in vertebrates: glimpse of the diversification in evolution.

    Science.gov (United States)

    Huang, Bei; Qi, Zhi T; Xu, Zhen; Nie, Pin

    2010-05-05

    Interferon regulatory factors (IRFs), which can be identified based on a unique helix-turn-helix DNA-binding domain (DBD) are a large family of transcription factors involved in host immune response, haemotopoietic differentiation and immunomodulation. Despite the identification of ten IRF family members in mammals, and some recent effort to identify these members in fish, relatively little is known in the composition of these members in other classes of vertebrates, and the evolution and probably the origin of the IRF family have not been investigated in vertebrates. Genome data mining has been performed to identify any possible IRF family members in human, mouse, dog, chicken, anole lizard, frog, and some teleost fish, mainly zebrafish and stickleback, and also in non-vertebrate deuterostomes including the hemichordate, cephalochordate, urochordate and echinoderm. In vertebrates, all ten IRF family members, i.e. IRF-1 to IRF-10 were identified, with two genes of IRF-4 and IRF-6 identified in fish and frog, respectively, except that in zebrafish exist three IRF-4 genes. Surprisingly, an additional member in the IRF family, IRF-11 was found in teleost fish. A range of two to ten IRF-like genes were detected in the non-vertebrate deuterostomes, and they had little similarity to those IRF family members in vertebrates as revealed in genomic structure and in phylogenetic analysis. However, the ten IRF family members, IRF-1 to IRF-10 showed certain degrees of conservation in terms of genomic structure and gene synteny. In particular, IRF-1, IRF-2, IRF-6, IRF-8 are quite conserved in their genomic structure in all vertebrates, and to a less degree, some IRF family members, such as IRF-5 and IRF-9 are comparable in the structure. Synteny analysis revealed that the gene loci for the ten IRF family members in vertebrates were also quite conservative, but in zebrafish conserved genes were distributed in a much longer distance in chromosomes. Furthermore, all ten different

  13. Lipid Synthetic Transcription Factor SREBP-1a Activates p21WAF1/CIP1, a Universal Cyclin-Dependent Kinase Inhibitor

    OpenAIRE

    INOUE, Noriyuki; Shimano, Hitoshi; Nakakuki, Masanori; Matsuzaka, Takashi; Nakagawa, Yoshimi; Yamamoto, Takashi; Sato, Ryuichiro; Takahashi, Akimitsu; Sone, Hirohito; Yahagi, Naoya; Suzuki, Hiroaki; Toyoshima, Hideo; Yamada, Nobuhiro

    2005-01-01

    Sterol regulatory element-binding proteins (SREBPs) are membrane-bound transcription factors that regulate lipid synthetic genes. In contrast to SREBP-2, which regulates cellular cholesterol level in normal cells, SREBP-1a is highly expressed in actively growing cells and activates entire programs of genes involved in lipid synthesis such as cholesterol, fatty acids, triglycerides, and phospholipids. Previously, the physiological relevance of this potent activity of SREBP-1a has been thought ...

  14. Pregna-5,17(20)-dien-21-oyl amides affecting sterol and triglyceride biosynthesis in Hep G2 cells.

    Science.gov (United States)

    Stulov, Sergey V; Mankevich, Olga V; Dugin, Nikita O; Novikov, Roman A; Timofeev, Vladimir P; Misharin, Alexander Yu

    2013-04-01

    Synthesis of series [17(20)Z]- and [17(20)E]-pregna-5,17(20)-dien-21-oyl amides, containing polar substituents in amide moiety, based on rearrangement of 17α-bromo-21-iodo-3β-acetoxypregn-5-en-20-one caused by amines, is presented. The titled compounds were evaluated for their potency to regulate sterol and triglyceride biosynthesis in human hepatoma Hep G2 cells in comparison with 25-hydroxycholesterol. Three [17(20)E]-pregna-5,17(20)-dien-21-oyl amides at a concentrations of 5 μM inhibited sterol biosynthesis and stimulated triglyceride biosynthesis; their regulatory potency was dependent on the structure of amide moiety; the isomeric [17(20)Z]-pregna-5,17(20)-dien-21-oyl amides were inactive.

  15. Genome-wide identification of the regulatory targets of a transcription factor using biochemical characterization and computational genomic analysis

    Directory of Open Access Journals (Sweden)

    Jolly Emmitt R

    2005-11-01

    Full Text Available Abstract Background A major challenge in computational genomics is the development of methodologies that allow accurate genome-wide prediction of the regulatory targets of a transcription factor. We present a method for target identification that combines experimental characterization of binding requirements with computational genomic analysis. Results Our method identified potential target genes of the transcription factor Ndt80, a key transcriptional regulator involved in yeast sporulation, using the combined information of binding affinity, positional distribution, and conservation of the binding sites across multiple species. We have also developed a mathematical approach to compute the false positive rate and the total number of targets in the genome based on the multiple selection criteria. Conclusion We have shown that combining biochemical characterization and computational genomic analysis leads to accurate identification of the genome-wide targets of a transcription factor. The method can be extended to other transcription factors and can complement other genomic approaches to transcriptional regulation.

  16. A DNA-binding-site landscape and regulatory network analysis for NAC transcription factors in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Lindemose, Søren; Jensen, Michael Krogh; de Velde, Jan Van

    2014-01-01

    regulatory networks of 12 NAC transcription factors. Our data offer specific single-base resolution fingerprints for most TFs studied and indicate that NAC DNA-binding specificities might be predicted from their DNA-binding domain's sequence. The developed methodology, including the application...... of complementary functional genomics filters, makes it possible to translate, for each TF, protein binding microarray data into a set of high-quality target genes. With this approach, we confirm NAC target genes reported from independent in vivo analyses. We emphasize that candidate target gene sets together......Target gene identification for transcription factors is a prerequisite for the systems wide understanding of organismal behaviour. NAM-ATAF1/2-CUC2 (NAC) transcription factors are amongst the largest transcription factor families in plants, yet limited data exist from unbiased approaches to resolve...

  17. Two New C29 Sterols from Clerodendrum colebrookianum

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    From the aerial parts of Clerodendrum colebrookianum Walp., two new C29 sterols, colebrin A and colebrin B, were isolated, along with a known compound, clerosterol .The structures of the new compounds were elucidated on the basis of spectral evidence.

  18. New cytotoxic oxygenated sterols from the marine bryozoan Cryptosula pallasiana.

    Science.gov (United States)

    Tian, Xiang-Rong; Tang, Hai-Feng; Li, Yu-Shan; Lin, Hou-Wen; Chen, Xiao-Li; Ma, Ning; Yao, Min-Na; Zhang, Ping-Hu

    2011-01-28

    Six new sterols (1-6), together with seven known sterols (7-13), were isolated from the CCl(4) extract of the marine bryozoan Cryptosula pallasiana, four (3-6) of which have already been reported as synthetic sterols. This is the first time that these compounds (3-6) are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D) NMR and HR-ESI-MS data. Compounds 1-4, 7 and 10-13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC(50) values from 14.73 to 22.11 µg/mL except for compounds 12 and 13.

  19. New Cytotoxic Oxygenated Sterols from the Marine Bryozoan Cryptosula pallasiana

    Directory of Open Access Journals (Sweden)

    Ping-Hu Zhang

    2011-01-01

    Full Text Available Six new sterols (1–6, together with seven known sterols (7–13, were isolated from the CCl4 extract of the marine bryozoan Cryptosula pallasiana, four (3–6 of which have already been reported as synthetic sterols. This is the first time that these compounds (3–6 are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D NMR and HR-ESI-MS data. Compounds 1–4, 7 and 10–13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC50 values from 14.73 to 22.11 µg/mL except for compounds 12 and 13.

  20. Identifying significant genetic regulatory networks in the prostate cancer from microarray data based on transcription factor analysis and conditional independency

    Directory of Open Access Journals (Sweden)

    Yeh Cheng-Yu

    2009-12-01

    Full Text Available Abstract Background Prostate cancer is a world wide leading cancer and it is characterized by its aggressive metastasis. According to the clinical heterogeneity, prostate cancer displays different stages and grades related to the aggressive metastasis disease. Although numerous studies used microarray analysis and traditional clustering method to identify the individual genes during the disease processes, the important gene regulations remain unclear. We present a computational method for inferring genetic regulatory networks from micorarray data automatically with transcription factor analysis and conditional independence testing to explore the potential significant gene regulatory networks that are correlated with cancer, tumor grade and stage in the prostate cancer. Results To deal with missing values in microarray data, we used a K-nearest-neighbors (KNN algorithm to determine the precise expression values. We applied web services technology to wrap the bioinformatics toolkits and databases to automatically extract the promoter regions of DNA sequences and predicted the transcription factors that regulate the gene expressions. We adopt the microarray datasets consists of 62 primary tumors, 41 normal prostate tissues from Stanford Microarray Database (SMD as a target dataset to evaluate our method. The predicted results showed that the possible biomarker genes related to cancer and denoted the androgen functions and processes may be in the development of the prostate cancer and promote the cell death in cell cycle. Our predicted results showed that sub-networks of genes SREBF1, STAT6 and PBX1 are strongly related to a high extent while ETS transcription factors ELK1, JUN and EGR2 are related to a low extent. Gene SLC22A3 may explain clinically the differentiation associated with the high grade cancer compared with low grade cancer. Enhancer of Zeste Homolg 2 (EZH2 regulated by RUNX1 and STAT3 is correlated to the pathological stage

  1. Sterols in a unicellular relative of the metazoans

    Science.gov (United States)

    Kodner, Robin B.; Summons, Roger E.; Pearson, Ann; King, Nicole; Knoll, Andrew H.

    2008-01-01

    Molecular clocks suggest that animals originated well before they first appear as macroscopic fossils, but geologic tests of these hypotheses have been elusive. A rare steroid hydrocarbon, 24-isopropylcholestane, has been hypothesized to be a biomarker for sponges or their immediate ancestors because of its relatively high abundance in pre-Ediacaran to Early Cambrian sedimentary rocks and oils. Biolipid precursors of this sterane have been reported to be prominent in several demosponges. Whether 24-isopropylcholestane can be interpreted as a sponge (and, hence, animal) biomarker, and so provide clues about early metazoan history, depends on an understanding of the distribution of sterol biosynthesis among animals and their protistan relatives. Accordingly, we characterized the sterol profile of the choanoflagellate Monosiga brevicollis, a representative of the unicellular sister group of animals. M. brevicollis does not produce a candidate sterol precursor for 24-isopropylcholestane under our experimental growth conditions. It does, however, produce a number of other sterols, and comparative genomics confirms its biosynthetic potential to produce the full suite of compounds recovered. Consistent with the phylogenetic position of choanoflagellates, the sterol profile and biosynthetic pathway of M. brevicollis display characteristics of both fungal and poriferan sterol biosynthesis. This is an example in which genomic and biochemical information have been used together to investigate the taxonomic specificity of a fossil biomarker. PMID:18632573

  2. Fiber, intestinal sterols, and colon cancer.

    Science.gov (United States)

    Huang, C T; Gopalakrishna, G S; Nichols, B L

    1978-03-01

    It has been postulated that dietary fiber's protective effect against the development of colon cancer, diverticular disease, and atherosclerosis may be due to the adsorption and/or dilution of intestinal sterols such as bile acids and neural sterols and their bacterial metabolites by component(s) of fiber. Dietary fiber is made up of four major components-cellulose, hemicellulose, lignin, and pectin. There is evidence that hemicellulose and pectin may induce an increase in fecal bile acid excretion in man which may be accompanied by a decrease in serum cholesterol. Natural fibers, such as rolled oats, alfalfa, guar gum, and Bengal gram have been shown to have hypocholesterolemic properties of alfalfa, wheat straw, and some other fibers found considerable amounts of bile acids in vitro. On the other hand, wheat bran, oat hulls, and all the synthetic fibers tested bound only negligible amounts of bile acids under the same conditions. Vegetarians in the United States have lower plasma lipids and different plasma lipoprotein patterns than those of comparable control populations on regular mixed diet. They also have smaller daily fractional turnover rates of cholic acid and deoxycholic acid pool size. In addition, populations on a mixed Western diet, where the rate of large bowel cancer is high (North American, English, Scottish, etc.) degraded and excreted cholesterol and bile acid metabolites to a greater degree than populations where the rate of colon cancer is comparatively low (Ugandan, Japanese, etc). It cannot be denied that the fiber theory linking fiber deficiency with the development of colon cancer and other diseases, is simple, attractive and appears to be firmly based in common sense. When subjected to research studies, however, the situation appears much more complex than expected. Although some progress is being made, the data are often contradictory and confusing, probably due to lack of adequate documentation of fiber intake (e.g., use of dietary fiber

  3. SURVEY OF THE STEROL COMPOSITION OF THE MARINE DINOFLAGELLATES KARENIA BREVIS, KARENIA MIKIMOTOI, AND KARLODINIUM MICRUM: DISTRIBUTION OF STEROLS WITHIN OTHER MEMBERS OF THE CLASS DINOPHYCEAE

    Science.gov (United States)

    The sterol composition of different marine microalgae was examined to determine the utility of sterols as biomarkers to distinguish members of various algal classes. For example, members of the class Dinophyceae possess certain 4-methyl sterols, such as dinosterol, which are rare...

  4. Effects of a Plant Sterol or Stanol Enriched Mixed Meal on Postprandial Lipid Metabolism in Healthy Subjects

    Science.gov (United States)

    Baumgartner, Sabine; Mensink, Ronald P.; Plat, Jogchum

    2016-01-01

    Background Evidence is increasing that plant sterols and stanols not only lower fasting serum low-density lipoprotein concentrations, but also those of triglycerides (TG). Insight into effects of these components on postprandial TG metabolism, an emerging risk factor for cardiovascular disease, is missing. Objective Our objective was to examine the 8-hour postprandial response after consuming plant sterol or stanol enriched margarine as part of a mixed meal. Methods This postprandial study was part of a randomized crossover study in which 42 subjects consumed plant sterol enriched (3 g/d plant sterols), plant stanol enriched (3 g/d plant stanols), and control margarines for 4 weeks. After each period, subjects consumed a shake enriched with 3g plant sterols (sterol period), 3g plant stanols (stanol period) or no addition (control period). Subjects received a second shake with no addition after 4 hours. Results TG and apoB48 incremental areas under the curves (iAUC) of the total (0-8h) and 1st meal response (0-4h) were comparable between the meals and in all age categories (I:18-35y, II:36-52y, III:53-69y). In subjects aged 53-69y, TG iAUC after the 2nd meal (4-8h) was higher in the stanol period as compared with the sterol (63.1±53.0 mmol/L/min; P sterol period (67.1±77.0 mg/L/min; P < 0.05) and tended to be higher than after the control period (43.1±64.5 mg/L/min; P = 0.08) in subjects aged 53-69y. These increased postprandial responses may be due to reduced lipoprotein lipase activity, since postprandial apoCIII/II ratios were increased after stanol consumption compared with the control meal. Conclusion Postprandial TG and apoB48 responses are age-dependently increased after plant stanol consumption, which might be related to a changed clearance of triglyceride-rich lipoproteins. Trial Registration ClinicalTrials.gov NCT01559428 PMID:27611192

  5. Osh proteins regulate membrane sterol organization but are not required for sterol movement between the ER and PM

    Science.gov (United States)

    Georgiev, Alexander; Sullivan, David P.; Kersting, Michael C.; Dittman, Jeremy S.; Beh, Christopher T.; Menon, Anant K.

    2011-01-01

    Sterol transport between the endoplasmic reticulum (ER) and plasma membrane (PM) occurs by an ATP-dependent, non-vesicular mechanism that is presumed to require sterol transport proteins (STPs). In Saccharomyces cerevisiae, homologues of the mammalian oxysterol-binding protein (Osh1–7) have been proposed to function as STPs. To evaluate this proposal we took two approaches. First we used dehydroergosterol (DHE) to visualize sterol movement in living cells by fluorescence microscopy. DHE was introduced into the PM under hypoxic conditions and observed to redistribute to lipid droplets on growing the cells aerobically. Redistribution required ATP and the sterol acyltransferase Are2, but did not require PM-derived transport vesicles. DHE redistribution occurred robustly in a conditional yeast mutant (oshΔ osh4-1ts) that lacks all functional Osh proteins at 37°C. In a second approach we used a pulse-chase protocol to analyze the movement of metabolically radiolabeled ergosterol from the ER to the PM. Arrival of radiolabeled ergosterol at the PM was assessed in isolated PM-enriched fractions as well by extracting sterols from intact cells with methyl-β-cyclodextrin. These experiments revealed that whereas ergosterol is transported effectively from the ER to the PM in Osh-deficient cells, the rate at which it moves within the PM to equilibrate with the methyl-β-cyclodextrin extractable sterol pool is slowed. We conclude (i) that the role of Osh proteins in nonvesicular sterol transport between the PM, ER and lipid droplets is either minimal, or subsumed by other mechanisms and (ii) that Osh proteins regulate the organization of sterols at the PM. PMID:21689253

  6. A novel interferon-inducible domain: structural and functional analysis of the human interferon regulatory factor 1 gene promoter.

    OpenAIRE

    1993-01-01

    We have cloned and functionally characterized the human interferon regulatory factor 1 (IRF-1) gene promoter. The promoter contains a CpG island, with several GC boxes, a CAAT box, but no TATA box. IRF-1 mRNA is strongly induced by gamma interferon (IFN-gamma) but more weakly and transiently by IFN-alpha. There are several putative kappa B motifs and numerous AA(G/A)G(G/T)A and GAAANN motifs throughout the promoter. The IRF-1 promoter is not autoregulated by the IRF-1 gene product. IFN induci...

  7. Uncovering MicroRNA and Transcription Factor Mediated Regulatory Networks in Glioblastoma

    OpenAIRE

    Jingchun Sun; Xue Gong; Benjamin Purow; Zhongming Zhao

    2012-01-01

    Glioblastoma multiforme (GBM) is the most common and lethal brain tumor in humans. Recent studies revealed that patterns of microRNA (miRNA) expression in GBM tissue samples are different from those in normal brain tissues, suggesting that a number of miRNAs play critical roles in the pathogenesis of GBM. However, little is yet known about which miRNAs play central roles in the pathology of GBM and their regulatory mechanisms of action. To address this issue, in this study, we systematically ...

  8. Fatigue risk management: Organizational factors at the regulatory and industry/company level.

    Science.gov (United States)

    Gander, Philippa; Hartley, Laurence; Powell, David; Cabon, Philippe; Hitchcock, Edward; Mills, Ann; Popkin, Stephen

    2011-03-01

    This paper focuses on the development of fatigue risk management systems (FRMS) in the transport sector. The evolution of regulatory frameworks is traced, from uni-dimensional hours of service regulations through to frameworks that enable multi-dimensional FRMS. These regulatory changes reflect advances in understanding of human error in the aetiology of accidents, and in fatigue and safety science. Implementation of FRMS shifts the locus of responsibility for safety away from the regulator towards companies and individuals, and requires changes in traditional roles. Organizational, ethnic, and national culture need to be considered. Recent trends in the work environment have potential to adversely affect FRMS, including precarious employment and shortages of skilled labour. Essential components of an FRMS, and examples of FRMS in different transport modes, are described. It is vital that regulators, employer, and employees have an understanding of the causes and consequences of fatigue that is sufficient for them to meet their responsibilities in relation to FRMS. While there is a strong evidence base supporting the principles of FRMS, experience with implementation is more limited. The evidence base for effective implementation will expand, since FRMS is data-driven, and ongoing evaluation is integral. We strongly advocate that experience be shared wherever possible. Copyright © 2009 Elsevier Ltd. All rights reserved.

  9. Regulatory Mechanisms Involved in the Expression of Brain-Derived Neurotrophic Factor and Glial Cell Line-Derived Neurotrophic Factor

    Science.gov (United States)

    1996-03-01

    Growth Factor Nerve growth factor (NGF), the prototypical neurotrophin, originally isolated by Levi -Montalcini and colleagues ( Levi -Montalcini, 1987; see...inclusion of NGF antibodies ( Levi -Montalcini, 1987). In addition, these neurons exhibit enhanced differentiation, as evidenced by extensive neurite...the nerve growth factor family reveal a novel member abundantly expressed in Xenopus ovary. Neuron 6: 845-858, 1991. Hefti, F. Nerve growth factor

  10. PcFKH1, a novel regulatory factor from the forkhead family, controls the biosynthesis of penicillin in Penicillium chrysogenum.

    Science.gov (United States)

    Domínguez-Santos, Rebeca; García-Estrada, Carlos; Kosalková, Katarina; Prieto, Carlos; Santamarta, Irene; Martín, Juan-Francisco

    2015-08-01

    Penicillin biosynthesis in Penicillium chrysogenum (re-identified as Penicillium rubens) is a good example of a biological process subjected to complex global regulatory networks and serves as a model to study fungal secondary metabolism. The winged-helix family of transcription factors recently described, which includes the forkhead type of proteins, is a key type of regulatory proteins involved in this process. In yeasts and humans, forkhead transcription factors are involved in different processes (cell cycle regulation, cell death control, pre-mRNA processing and morphogenesis); one member of this family of proteins has been identified in the P. chrysogenum genome (Pc18g00430). In this work, we have characterized this novel transcription factor (named PcFKH1) by generating knock-down mutants and overexpression strains. Results clearly indicate that PcFKH1 positively controls antibiotic biosynthesis through the specific interaction with the promoter region of the penDE gene, thus regulating penDE mRNA levels. PcFKH1 also binds to the pcbC promoter, but with low affinity. In addition, it also controls other ancillary genes of the penicillin biosynthetic process, such as phlA (encoding phenylacetyl CoA ligase) and ppt (encoding phosphopantetheinyl transferase). PcFKH1 also plays a role in conidiation and spore pigmentation, but it does not seem to be involved in hyphal morphology or cell division in the improved laboratory reference strain Wisconsin 54-1255. A genome-wide analysis of processes putatively coregulated by PcFKH1 and PcRFX1 (another winged-helix transcription factor) in P. chrysogenum provided evidence of the global effect of these transcription factors in P. chrysogenum metabolism.

  11. A Minimal Regulatory Network of Extrinsic and Intrinsic Factors Recovers Observed Patterns of CD4+ T Cell Differentiation and Plasticity.

    Directory of Open Access Journals (Sweden)

    Mariana Esther Martinez-Sanchez

    2015-06-01

    Full Text Available CD4+ T cells orchestrate the adaptive immune response in vertebrates. While both experimental and modeling work has been conducted to understand the molecular genetic mechanisms involved in CD4+ T cell responses and fate attainment, the dynamic role of intrinsic (produced by CD4+ T lymphocytes versus extrinsic (produced by other cells components remains unclear, and the mechanistic and dynamic understanding of the plastic responses of these cells remains incomplete. In this work, we studied a regulatory network for the core transcription factors involved in CD4+ T cell-fate attainment. We first show that this core is not sufficient to recover common CD4+ T phenotypes. We thus postulate a minimal Boolean regulatory network model derived from a larger and more comprehensive network that is based on experimental data. The minimal network integrates transcriptional regulation, signaling pathways and the micro-environment. This network model recovers reported configurations of most of the characterized cell types (Th0, Th1, Th2, Th17, Tfh, Th9, iTreg, and Foxp3-independent T regulatory cells. This transcriptional-signaling regulatory network is robust and recovers mutant configurations that have been reported experimentally. Additionally, this model recovers many of the plasticity patterns documented for different T CD4+ cell types, as summarized in a cell-fate map. We tested the effects of various micro-environments and transient perturbations on such transitions among CD4+ T cell types. Interestingly, most cell-fate transitions were induced by transient activations, with the opposite behavior associated with transient inhibitions. Finally, we used a novel methodology was used to establish that T-bet, TGF-β and suppressors of cytokine signaling proteins are keys to recovering observed CD4+ T cell plastic responses. In conclusion, the observed CD4+ T cell-types and transition patterns emerge from the feedback between the intrinsic or intracellular

  12. A Minimal Regulatory Network of Extrinsic and Intrinsic Factors Recovers Observed Patterns of CD4+ T Cell Differentiation and Plasticity

    Science.gov (United States)

    Martinez-Sanchez, Mariana Esther; Mendoza, Luis; Villarreal, Carlos; Alvarez-Buylla, Elena R.

    2015-01-01

    CD4+ T cells orchestrate the adaptive immune response in vertebrates. While both experimental and modeling work has been conducted to understand the molecular genetic mechanisms involved in CD4+ T cell responses and fate attainment, the dynamic role of intrinsic (produced by CD4+ T lymphocytes) versus extrinsic (produced by other cells) components remains unclear, and the mechanistic and dynamic understanding of the plastic responses of these cells remains incomplete. In this work, we studied a regulatory network for the core transcription factors involved in CD4+ T cell-fate attainment. We first show that this core is not sufficient to recover common CD4+ T phenotypes. We thus postulate a minimal Boolean regulatory network model derived from a larger and more comprehensive network that is based on experimental data. The minimal network integrates transcriptional regulation, signaling pathways and the micro-environment. This network model recovers reported configurations of most of the characterized cell types (Th0, Th1, Th2, Th17, Tfh, Th9, iTreg, and Foxp3-independent T regulatory cells). This transcriptional-signaling regulatory network is robust and recovers mutant configurations that have been reported experimentally. Additionally, this model recovers many of the plasticity patterns documented for different T CD4+ cell types, as summarized in a cell-fate map. We tested the effects of various micro-environments and transient perturbations on such transitions among CD4+ T cell types. Interestingly, most cell-fate transitions were induced by transient activations, with the opposite behavior associated with transient inhibitions. Finally, we used a novel methodology was used to establish that T-bet, TGF-β and suppressors of cytokine signaling proteins are keys to recovering observed CD4+ T cell plastic responses. In conclusion, the observed CD4+ T cell-types and transition patterns emerge from the feedback between the intrinsic or intracellular regulatory core

  13. Identifying avian sources of faecal contamination using sterol analysis.

    Science.gov (United States)

    Devane, Megan L; Wood, David; Chappell, Andrew; Robson, Beth; Webster-Brown, Jenny; Gilpin, Brent J

    2015-10-01

    Discrimination of the source of faecal pollution in water bodies is an important step in the assessment and mitigation of public health risk. One tool for faecal source tracking is the analysis of faecal sterols which are present in faeces of animals in a range of distinctive ratios. Published ratios are able to discriminate between human and herbivore mammal faecal inputs but are of less value for identifying pollution from wildfowl, which can be a common cause of elevated bacterial indicators in rivers and streams. In this study, the sterol profiles of 50 avian-derived faecal specimens (seagulls, ducks and chickens) were examined alongside those of 57 ruminant faeces and previously published sterol profiles of human wastewater, chicken effluent and animal meatwork effluent. Two novel sterol ratios were identified as specific to avian faecal scats, which, when incorporated into a decision tree with human and herbivore mammal indicative ratios, were able to identify sterols from avian-polluted waterways. For samples where the sterol profile was not consistent with herbivore mammal or human pollution, avian pollution is indicated when the ratio of 24-ethylcholestanol/(24-ethylcholestanol + 24-ethylcoprostanol + 24-ethylepicoprostanol) is ≥0.4 (avian ratio 1) and the ratio of cholestanol/(cholestanol + coprostanol + epicoprostanol) is ≥0.5 (avian ratio 2). When avian pollution is indicated, further confirmation by targeted PCR specific markers can be employed if greater confidence in the pollution source is required. A 66% concordance between sterol ratios and current avian PCR markers was achieved when 56 water samples from polluted waterways were analysed.

  14. Sterols of Pneumocystis carinii hominis Organisms Isolated from Human Lungs

    Science.gov (United States)

    Kaneshiro, Edna S.; Amit, Zunika; Chandra, Jyotsna; Baughman, Robert P.; Contini, Carlo; Lundgren, Bettina

    1999-01-01

    The opportunistic pathogen Pneumocystis carinii causes pneumonia (P. carinii pneumonia, or PCP) in immunocompromised individuals such as AIDS patients. Rat-derived P. carinii carinii organisms have distinct sterols which are not synthesized by mammals and not found in other microbes infecting mammalian lungs. The dominant sterol present in the organism is cholesterol (which is believed to be scavenged from the host), but other sterols in P. carinii carinii have an alkyl group at C-24 of the sterol side chain (C28 and C29 24-alkylsterols) and a double bond at C-7 of the nucleus. Recently, pneumocysterol (C32), which is essentially lanosterol with a C-24 ethylidene group, was detected in lipids extracted from a formalin-fixed human P. carinii-infected lung, and its structures were elucidated by gas-liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectrometry in conjunction with analyses of chemically synthesized authentic standards. The sterol composition of isolated P. carinii hominis organisms has yet to be reported. If P. carinii from animal models is to be used for identifying potential drug targets and for developing chemotherapeutic approaches to clear human infections, it is important to determine whether the 24-alkylsterols of organisms found in rats are also present in organisms in humans. In the present study, sterol analyses of P. carinii hominis organisms isolated from cryopreserved human P. carinii-infected lungs and from bronchoalveolar lavage fluid were performed. Several of the same distinct sterols (e.g., fungisterol and methylcholest-7-ene-3β-ol) previously identified in P. carinii carinii were also present in organisms isolated from human specimens. Pneumocysterol was detected in only some of the samples. PMID:10548595

  15. Free and Esterified Sterol Distribution in Four Romanian Vegetable Oil

    Directory of Open Access Journals (Sweden)

    Francisc Vasile DULF

    2010-09-01

    Full Text Available The unsaponifiable lipid fraction of plant-based foods is a potential source of bioactive components such as phytosterols, triterpenoids, carotenoids, tocopherols and various hydrocarbons. The free and esterified sterol concentrations in four Romanian edible oils (corn germ, wheat germ, sweet almond and grape seed oil were determined, including individual values for β-sitosterol, campesterol, stigmasterol, Δ5-avenasterol, sitostanol, campestanol, and cholesterol. Free and esterified sterols were separated by solid-phase extraction (SPE, saponified, and analyzed as trimethylsilyl ether derivatives using gas-chromatography (GC with flame ionization detector (FID. Differences in total sterol content and the proportion of esterified (ES and free sterols (FS were evident for studied oil samples. In general, β-sitosterol was the most prevalent phytosterol, ranging in concentration from 158.3 mg/100 g in grape seed oil to 478.5 mg/100 g in corn germ oil. Only in these two vegetable oil, we identified trace amount of cholesterol (<3 mg/100g. The total sterol concentrations ranged from 199.9 mg/100g (sweet almond oil to 745.2 mg/100 g (corn germ oil. In corn germ and wheat germ oil, the dominant form of sterols was the esterified one (60.7% ES and 55.6% ES, respectively, of total sterols. This study consolidates the view that vegetable oils are good natural sources of phytosterols. The analyses of these components provide rich information about the identity and quality of vegetable oils. The corn germ and wheat germ oils proved to be the richest sources in phytosterols, being recommended as functional oils.

  16. Boundaries of regulatory fit: Is it the thought that counts?

    DEFF Research Database (Denmark)

    Leikas, S.; Lindeman, M.; Roininen, K.

    2009-01-01

    (N = 71) first completed a regulatory focus manipulation task and were then led to believe that they would receive either rich or accurate information concerning vegetable sterols, evoking beliefs that they used eager or vigilant information search strategies. In reality, all participants received...

  17. RNA-Seq analysis uncovers non-coding small RNA system of Mycobacterium neoaurum in the metabolism of sterols to accumulate steroid intermediates.

    Science.gov (United States)

    Liu, Min; Zhu, Zhan-Tao; Tao, Xin-Yi; Wang, Feng-Qing; Wei, Dong-Zhi

    2016-04-25

    Understanding the metabolic mechanism of sterols to produce valuable steroid intermediates in mycobacterium by a noncoding small RNA (sRNA) view is still limited. In the work, RNA-seq was implemented to investigate the noncoding transcriptome of Mycobacterium neoaurum (Mn) in the transformation process of sterols to valuable steroid intermediates, including 9α-hydroxy-4-androstene-3,17-dione (9OHAD), 1,4-androstadiene-3,17-dione (ADD), and 22-hydroxy-23, 24-bisnorchola-1,4-dien-3-one (1,4-BNA). A total of 263 sRNA candidates were predicted from the intergenic regions in Mn. Differential expression of sRNA candidates was explored in the wide type Mn with vs without sterol addition, and the steroid intermediate producing Mn strains vs wide type Mn with sterol addition, respectively. Generally, sRNA candidates were differentially expressed in various strains, but there were still some shared candidates with outstandingly upregulated or downregulated expression in these steroid producing strains. Accordingly, four regulatory networks were constructed to reveal the direct and/or indirect interactions between sRNA candidates and their target genes in four groups, including wide type Mn with vs without sterol addition, 9OHAD, ADD, and BNA producing strains vs wide type Mn with sterol addition, respectively. Based on these constructed networks, several highly focused sRNA candidates were discovered to be prevalent in the networks, which showed comprehensive regulatory roles in various cellular processes, including lipid transport and metabolism, amino acid transport and metabolism, signal transduction, cell envelope biosynthesis and ATP synthesis. To explore the functional role of sRNA candidates in Mn cells, we manipulated the overexpression of candidates 131 and 138 in strain Mn-9OHAD, which led to enhanced production of 9OHAD from 1.5- to 2.3-fold during 6 d' fermentation and a slight effect on growth rate. This study revealed the complex and important regulatory

  18. Development of safety and regulatory requirements for Korean next generation reactor - Development of human factors design review guidelines (II)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Woon; Oh, In Suk; Lee, Hyun Chul; Cheon, Se Woo [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-02-01

    The objective of this study is to develop human factors engineering program review guidelines and alarm system review guidelines in order to resolve the two major technical issues: '25. Human Factors Engineering Program Review Model' and '26. Review Criteria for Human Factors Aspects of Advanced Controls and Instrumentation', which are related to the development of human factors safety regulation guides being performed by KINS. For the development of human factors program review guidelines, we made a Korean version of NUREG-0711 and added our comments by considering Korean regulatory situation and the characteristics of the KNGR design, and reviewing the reference documents of NURGE-0711. We also computerized the Korean version of NUREG-0711, additional comments, and selected portion of the reference documents for the developer of safety regulation guides at KINS to see the contents comparatively at a glance and use them easily. For the development of alarm system design review guidelines, we made a Korean version of NUREG/CR-6105, which was published by NRC in 1994 as a guideline document for the human factors review of alarm systems. Then we updated the guidelines by reviewing the literature related to alarm design that published after 1994. 12 refs., 11 figs., 2 tabs. (Author)

  19. Immune regulatory gene polymorphisms as predisposing risk factors for the development of factor VIII inhibitors in Indian severe haemophilia A patients.

    Science.gov (United States)

    Pinto, P; Ghosh, K; Shetty, S

    2012-09-01

    Development of inhibitors to factor VIII, a serious complication of replacement therapy in haemophilia A patients, leads to increased bleeding, morbidity and mortality. There is no data on the risk factors for inhibitor development in Indian patients with severe haemophilia A. Our aim was to study the role of immune regulatory gene polymorphisms in the development of inhibitors. Fourteen immune regulatory gene polymorphisms (IL1β, IL4, IL10, TNFA and CTLA4) were analysed in 120 patients with severe haemophilia A, i.e. 50 inhibitor positive patients, and 70 inhibitor negative control patients, by PCR-RFLP, DNA sequencing and allele-specific PCRs. The IL10 promoter 'GCC' haplotypes overall (P: 0.002, OR: 3.452, 95% CI: 1.607-7.416), and 'GCC/ATA' (P: 0.011, OR: 3.492, 95% CI: 1.402-8.696) haplotype, associated with high and intermediate IL10 production, respectively, were significantly higher in inhibitor positive patients, whereas the 'non-GCC' haplotypes overall (P: 0.002,OR: 0.290, 95% CI 0.135-0.622) and 'ATA/ATA' haplotype (P: 0.025, OR: 0.278, 95% CI: 0.096-0.802), associated with low IL10 synthesis, were significantly higher among inhibitor negative patients. The TNFA rs1799724 C/T heterozygote prevalence was significantly higher in the inhibitor positive group (P: 0.021, OR: 3.190, 95% CI: 1.273-7.990), whereas the other polymorphisms showed no statistically significant association with the presence of inhibitors. Different immune regulatory gene polymorphisms play a significant role as possible risk factors for the development of inhibitors in severe haemophilia A patients. © 2012 Blackwell Publishing Ltd.

  20. Two new monoclonal antibodies for biochemical and flow cytometric analyses of human interferon regulatory factor-3 activation, turnover, and depletion.

    Science.gov (United States)

    Rustagi, Arjun; Doehle, Brian P; McElrath, M Juliana; Gale, Michael

    2013-02-01

    Interferon regulatory factor-3 (IRF-3) is a master transcription factor that drives the host intracellular innate immune response to virus infection. The importance of IRF-3 in innate immune responses is highlighted by the fact that pathogenic viruses have developed strategies for antagonism of IRF-3. Several tools exist for evaluation of viral regulation of IRF-3 activation and function, but high-quality monoclonal antibodies that mark the differential activation states of human IRF-3 are lacking. To study IRF-3 activation, turnover, and depletion in a high-throughput manner in the context of virus infection, we have developed two new monoclonal antibodies to human IRF-3. These antibodies detect IRF-3 in virus-infected cells in a wide variety of assays and provide a new tool to study virus-host interactions and innate immune signaling.

  1. Sterols indicate water quality and wastewater treatment efficiency.

    Science.gov (United States)

    Reichwaldt, Elke S; Ho, Wei Y; Zhou, Wenxu; Ghadouani, Anas

    2017-01-01

    As the world's population continues to grow, water pollution is presenting one of the biggest challenges worldwide. More wastewater is being generated and the demand for clean water is increasing. To ensure the safety and health of humans and the environment, highly efficient wastewater treatment systems, and a reliable assessment of water quality and pollutants are required. The advance of holistic approaches to water quality management and the increasing use of ecological water treatment technologies, such as constructed wetlands and waste stabilisation ponds (WSPs), challenge the appropriateness of commonly used water quality indicators. Instead, additional indicators, which are direct measures of the processes involved in the stabilisation of human waste, have to be established to provide an in-depth understanding of system performance. In this study we identified the sterol composition of wastewater treated in WSPs and assessed the suitability of human sterol levels as a bioindicator of treatment efficiency of wastewater in WSPs. As treatment progressed in WSPs, the relative abundance of human faecal sterols, such as coprostanol, epicoprostanol, 24-ethylcoprostanol, and sitostanol decreased significantly and the sterol composition in wastewater changed significantly. Furthermore, sterol levels were found to be correlated with commonly used wastewater quality indicators, such as BOD, TSS and E. coli. Three of the seven sterol ratios that have previously been used to track sewage pollution in the environment, detected a faecal signal in the effluent of WSPs, however, the others were influenced by high prevalence of sterols originating from algal and fungal activities. This finding poses a concern for environmental assessment studies, because environmental pollution from waste stabilisation ponds can go unnoticed. In conclusion, faecal sterols and their ratios can be used as reliable indicators of treatment efficiency and water quality during wastewater

  2. Plant phloem sterol content: forms, putative functions, and implications for phloem-feeding insects

    Directory of Open Access Journals (Sweden)

    Spencer eBehmer

    2013-09-01

    Full Text Available All eukaryotes contain sterols, which serve as structural components in cell membranes, and as precursors for important hormones. Plant vegetative tissues are known to contain mixtures of sterols, but very little is known about the sterol composition of phloem. Plants are food for many animals, but plant-feeding arthropods (including phloem-feeding insets are unique among animals in that they have lost the ability to synthesize sterols, and must therefore acquire these essential nutrients from their food, or via endosymbionts. Our paper starts by providing a very brief overview of variation in plant sterol content, and how different sterols can affect insect herbivores, including those specializing on phloem. We then describe an experiment, where we bulk collected phloem sap exudate from bean and tobacco, and analyzed its sterol content. This approach revealed two significant observations concerning phloem sterols. First, the phloem exudate from each plant was found to contain sterols in three different fractions – free sterols, sterols conjugated to lipids (acylated, and sterols conjugated to carbohydrates (glycosylated. Second, for both plants, cholesterol was identified as the dominant sterol in each phloem exudate fraction; the remaining sterol in the fraction was a mixture of common phytosterols. We discuss our phloem exudate sterol profiles in a plant physiology/biochemistry context, and how it relates to the nutritional physiology/ecology of phloem-feeding insects. We close by proposing important next steps that will advance our knowledge concerning plant phloem sterol biology, and how phloem-sterol content might affect phloem-feeding insects.

  3. Genetic variation in plant CYP51s confers resistance against voriconazole, a novel inhibitor of brassinosteroid-dependent sterol biosynthesis.

    Directory of Open Access Journals (Sweden)

    Wilfried Rozhon

    Full Text Available Brassinosteroids (BRs are plant steroid hormones with structural similarity to mammalian sex steroids and ecdysteroids from insects. The BRs are synthesized from sterols and are essential regulators of cell division, cell elongation and cell differentiation. In this work we show that voriconazole, an antifungal therapeutic drug used in human and veterinary medicine, severely impairs plant growth by inhibiting sterol-14α-demethylation and thereby interfering with BR production. The plant growth regulatory properties of voriconazole and related triazoles were identified in a screen for compounds with the ability to alter BR homeostasis. Voriconazole suppressed growth of the model plant Arabidopsis thaliana and of a wide range of both monocotyledonous and dicotyledonous plants. We uncover that voriconazole toxicity in plants is a result of a deficiency in BRs that stems from an inhibition of the cytochrome P450 CYP51, which catalyzes a step of BR-dependent sterol biosynthesis. Interestingly, we found that the woodland strawberry Fragaria vesca, a member of the Rosaceae, is naturally voriconazole resistant and that this resistance is conferred by the specific CYP51 variant of F. vesca. The potential of voriconazole as a novel tool for plant research is discussed.

  4. Integrative analysis of the zinc finger transcription factor Lame duck in the Drosophila myogenic gene regulatory network.

    Science.gov (United States)

    Busser, Brian W; Huang, Di; Rogacki, Kevin R; Lane, Elizabeth A; Shokri, Leila; Ni, Ting; Gamble, Caitlin E; Gisselbrecht, Stephen S; Zhu, Jun; Bulyk, Martha L; Ovcharenko, Ivan; Michelson, Alan M

    2012-12-11

    Contemporary high-throughput technologies permit the rapid identification of transcription factor (TF) target genes on a genome-wide scale, yet the functional significance of TFs requires knowledge of target gene expression patterns, cooperating TFs, and cis-regulatory element (CRE) structures. Here we investigated the myogenic regulatory network downstream of the Drosophila zinc finger TF Lame duck (Lmd) by combining both previously published and newly performed genomic data sets, including ChIP sequencing (ChIP-seq), genome-wide mRNA profiling, cell-specific expression patterns of putative transcriptional targets, analysis of histone mark signatures, studies of TF cooccupancy by additional mesodermal regulators, TF binding site determination using protein binding microarrays (PBMs), and machine learning of candidate CRE motif compositions. Our findings suggest that Lmd orchestrates an extensive myogenic regulatory network, a conclusion supported by the identification of Lmd-dependent genes, histone signatures of Lmd-bound genomic regions, and the relationship of these features to cell-specific gene expression patterns. The heterogeneous cooccupancy of Lmd-bound regions with additional mesodermal regulators revealed that different transcriptional inputs are used to mediate similar myogenic gene expression patterns. Machine learning further demonstrated diverse combinatorial motif patterns within tissue-specific Lmd-bound regions. PBM analysis established the complete spectrum of Lmd DNA binding specificities, and site-directed mutagenesis of Lmd and additional newly discovered motifs in known enhancers demonstrated the critical role of these TF binding sites in supporting full enhancer activity. Collectively, these findings provide insights into the transcriptional codes regulating muscle gene expression and offer a generalizable approach for similar studies in other systems.

  5. Genomic analysis of host - Peste des petits ruminants vaccine viral transcriptome uncovers transcription factors modulating immune regulatory pathways.

    Science.gov (United States)

    Manjunath, Siddappa; Kumar, Gandham Ravi; Mishra, Bishnu Prasad; Mishra, Bina; Sahoo, Aditya Prasad; Joshi, Chaitanya G; Tiwari, Ashok K; Rajak, Kaushal Kishore; Janga, Sarath Chandra

    2015-02-24

    Peste des petits ruminants (PPR), is an acute transboundary viral disease of economic importance, affecting goats and sheep. Mass vaccination programs around the world resulted in the decline of PPR outbreaks. Sungri 96 is a live attenuated vaccine, widely used in Northern India against PPR. This vaccine virus, isolated from goat works efficiently both in sheep and goat. Global gene expression changes under PPR vaccine virus infection are not yet well defined. Therefore, in this study we investigated the host-vaccine virus interactions by infecting the peripheral blood mononuclear cells isolated from goat with PPRV (Sungri 96 vaccine virus), to quantify the global changes in the transcriptomic signature by RNA-sequencing. Viral genome of Sungri 96 vaccine virus was assembled from the PPRV infected transcriptome confirming the infection and demonstrating the feasibility of building a complete non-host genome from the blood transcriptome. Comparison of infected transcriptome with control transcriptome revealed 985 differentially expressed genes. Functional analysis showed enrichment of immune regulatory pathways under PPRV infection. Key genes involved in immune system regulation, spliceosomal and apoptotic pathways were identified to be dysregulated. Network analysis revealed that the protein - protein interaction network among differentially expressed genes is significantly disrupted in infected state. Several genes encoding TFs that govern immune regulatory pathways were identified to co-regulate the differentially expressed genes. These data provide insights into the host - PPRV vaccine virus interactome for the first time. Our findings suggested dysregulation of immune regulatory pathways and genes encoding Transcription Factors (TFs) that govern these pathways in response to viral infection.

  6. RNA-Sequencing Analysis Reveals a Regulatory Role for Transcription Factor Fezf2 in the Mature Motor Cortex

    Directory of Open Access Journals (Sweden)

    Alison J. Clare

    2017-09-01

    Full Text Available Forebrain embryonic zinc finger (Fezf2 encodes a transcription factor essential for the specification of layer 5 projection neurons (PNs in the developing cerebral cortex. As with many developmental transcription factors, Fezf2 continues to be expressed into adulthood, suggesting it remains crucial to the maintenance of neuronal phenotypes. Despite the continued expression, a function has yet to be explored for Fezf2 in the PNs of the developed cortex. Here, we investigated the role of Fezf2 in mature neurons, using lentiviral-mediated delivery of a shRNA to conditionally knockdown the expression of Fezf2 in the mouse primary motor cortex (M1. RNA-sequencing analysis of Fezf2-reduced M1 revealed significant changes to the transcriptome, identifying a regulatory role for Fezf2 in the mature M1. Kyoto Encyclopedia Genes and Genomes (KEGG pathway analyses of Fezf2-regulated genes indicated a role in neuronal signaling and plasticity, with significant enrichment of neuroactive ligand-receptor interaction, cell adhesion molecules and calcium signaling pathways. Gene Ontology analysis supported a functional role for Fezf2-regulated genes in neuronal transmission and additionally indicated an importance in the regulation of behavior. Using the mammalian phenotype ontology database, we identified a significant overrepresentation of Fezf2-regulated genes associated with specific behavior phenotypes, including associative learning, social interaction, locomotor activation and hyperactivity. These roles were distinct from that of Fezf2-regulated genes identified in development, indicating a dynamic transition in Fezf2 function. Together our findings demonstrate a regulatory role for Fezf2 in the mature brain, with Fezf2-regulated genes having functional roles in sustaining normal neuronal and behavioral phenotypes. These results support the hypothesis that developmental transcription factors are important for maintaining neuron transcriptomes and that

  7. Shielding hospital rooms for brachytherapy patients: design, regulatory and cost/benefit factors.

    Science.gov (United States)

    Gitterman, M; Webster, E W

    1984-03-01

    The current regulations of the U.S. Nuclear Regulatory Commission (NRC) normally require limitation of radiation exposure in any part of unrestricted occupied areas to 2 mrem in any one hour and to 100 mrem in 7 days. To meet these limits when patients are treated therapeutically with radioactive materials, it is advisable to designate specific rooms in a hospital and often necessary to incorporate substantial costly shielding into one or more walls and the room door. Plans have been formulated for shielding existing hospital rooms housing brachytherapy patients receiving 192Ir and 137Cs therapy in order to meet the above NRC requirements for adjacent corridors and rooms. Typical shielding thicknesses required are 4-6 in. of concrete for certain walls and 1/4 in. of lead in the doors. Shielding costs are approx. $6000 per room for one shielded wall and a shielded door. Applying recent estimates of the cancer risk from low-level gamma radiation, the cost of shielding per cancer fatality averted has been estimated to range from $1.8 million to $10.9 million. Cost/benefit comparisons with many other life-saving activities suggest that these costs and the application of the 2 mrem/hr limit which necessitated them are not justified.

  8. PreImplantation factor (PIF*) regulates systemic immunity and targets protective regulatory and cytoskeleton proteins.

    Science.gov (United States)

    Barnea, Eytan R; Hayrabedyan, Soren; Todorova, Krassimira; Almogi-Hazan, Osnat; Or, Reuven; Guingab, Joy; McElhinney, James; Fernandez, Nelson; Barder, Timothy

    2016-07-01

    Secreted by viable embryos, PIF is expressed by the placenta and found in maternal circulation. It promotes implantation and trophoblast invasion, achieving systemic immune homeostasis. Synthetic PIF successfully transposes endogenous PIF features to non-pregnant immune and transplant models. PIF affects innate and activated PBMC cytokines and genes expression. We report that PIF targets similar proteins in CD14+, CD4+ and CD8+ cells instigating integrated immune regulation. PIF-affinity chromatography followed by mass-spectrometry, pathway and heatmap analysis reveals that SET-apoptosis inhibitor, vimentin, myosin-9 and calmodulin are pivotal for immune regulation. PIF acts on macrophages down-stream of LPS (lipopolysaccharide-bacterial antigen) CD14/TLR4/MD2 complex, targeting myosin-9, thymosin-α1 and 14-3-3eta. PIF mainly targets platelet aggregation in CD4+, and skeletal proteins in CD8+ cells. Pathway analysis demonstrates that PIF targets and regulates SET, tubulin, actin-b, and S100 genes expression. PIF targets systemic immunity and has a short circulating half-life. Collectively, PIF targets identified; protective, immune regulatory and cytoskeleton proteins reveal mechanisms involved in the observed efficacy against immune disorders. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. A trans-acting Variant within the Transcription Factor RIM101 Interacts with Genetic Background to Determine its Regulatory Capacity.

    Science.gov (United States)

    Read, Timothy; Richmond, Phillip A; Dowell, Robin D

    2016-01-01

    Most genetic variants associated with disease occur within regulatory regions of the genome, underscoring the importance of defining the mechanisms underlying differences in regulation of gene expression between individuals. We discovered a pair of co-regulated, divergently oriented transcripts, AQY2 and ncFRE6, that are expressed in one strain of Saccharomyces cerevisiae, ∑1278b, but not in another, S288c. By combining classical genetics techniques with high-throughput sequencing, we identified a trans-acting single nucleotide polymorphism within the transcription factor RIM101 that causes the background-dependent expression of both transcripts. Subsequent RNA-seq experiments revealed that RIM101 regulates many more targets in S288c than in ∑1278b and that deletion of RIM101 in both backgrounds abrogates the majority of differential expression between the strains. Strikingly, only three transcripts undergo a significant change in expression after swapping RIM101 alleles between backgrounds, implying that the differences in the RIM101 allele lead to a remarkably focused transcriptional response. However, hundreds of RIM101-dependent targets undergo a subtle but consistent shift in expression in the S288c RIM101-swapped strain, but not its ∑1278b counterpart. We conclude that ∑1278b may harbor a variant(s) that buffers against widespread transcriptional dysregulation upon introduction of a non-native RIM101 allele, emphasizing the importance of accounting for genetic background when assessing the impact of a regulatory variant.

  10. Sterols as biomarkers in the surface microlayer of the estuarine areas.

    Science.gov (United States)

    Alsalahi, Murad Ali; Latif, Mohd Talib; Ali, Masni Mohd; Dominick, Doreena; Khan, Md Firoz; Mustaffa, Nur Ili Hamizah; Nadzir, Mohd Shahrul Mohd; Nasher, Essam; Zakaria, Mohamad Pauzi

    2015-04-15

    This study aims to determine the concentration of sterols used as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. Samples were collected during different seasons through the use of a rotation drum. The analysis of sterols was performed using gas chromatography equipped with a flame ionisation detector (GC-FID). The results showed that the concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L(-1). The total sterol concentration was found to be higher in the wet season. Cholesterol was found to be the most abundant sterols component in the SML. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).

  11. Comparative seasonal sterol profiles in edible parts of Mediterranean fish and shellfish species.

    Science.gov (United States)

    Ozyurt, Gülsün; Kuley, Esmeray; Etyemez, Miray; Ozoğul, Fatih

    2013-06-01

    The effect of different seasons on sterol content of seafoods was investigated. There were four sterols (cholesterol, sitosterol, desmosterol and stigmasterol) identified, with cholesterol being the predominant sterol. Stigmasterol was a minor component in fish muscle, whilst sitosterol was one of the main phytosterols found in fish muscle. Cholesterol content of fish consisted of 38-100% of total sterols in fish and 54-80% of total sterols in shellfish. The highest cholesterol content of fish muscle was found in summer and the lowest in autumn, whereas season did not have any effect on cholesterol level of green tiger prawn and speckled shrimp. Total sterol content of fish muscle ranged from 49 to 110 mg/100 g, although the range of total sterols in shrimp muscle was between 62 and 91 mg/100 g. The result of the study showed that total sterols in fish were generally found at lower levels in winter compared with other seasons.

  12. Plant sterol metabolism. Δ7-Sterol-C5-Desaturase (STE1/DWARF7), Δ5,7-Sterol-Δ7-Reductase (DWARF5) and Δ24-Sterol-Δ24-Reductase (DIMINUTO/DWARF1) show multiple subcellular localizations in Arabidopsis thaliana (Heynh) L

    DEFF Research Database (Denmark)

    Silvestro, Daniele; Andersen, Tonni Grube; Schaller, Hubert

    2013-01-01

    Sterols are crucial lipid components that regulate membrane permeability and fluidity and are the precursors of bioactive steroids. The plant sterols exist as three major forms, free sterols, steryl glycosides and steryl esters. The storage of steryl esters in lipid droplets has been shown...... to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map...... of steroidogenic enzymes in cells, the coding regions of ¿(7)-sterol-C(5)-desaturase (STE1/DWARF7), ¿(24)-sterol-¿(24)-reductase (DIMINUTO/DWARF1) and ¿(5,7)-sterol-¿(7)-reductase (DWARF5) were fused to the yellow fluorescent protein (YFP) and transformed into Arabidopsis thaliana mutant lines deficient...

  13. A data mining approach to dinoflagellate clustering according to sterol composition: Correlations with evolutionary history.

    Science.gov (United States)

    This study examined the sterol compositions of 102 dinoflagellates (including several previously unexamined species) using clustering techniques as a means of determining the relatedness of the organisms. In addition, dinoflagellate sterol-based relationships were compared statistically to dinoflag...

  14. Plant sterol metabolism. Δ7-Sterol-C5-Desaturase (STE1/DWARF7), Δ5,7-Sterol-Δ7-Reductase (DWARF5) and Δ24-Sterol-Δ24-Reductase (DIMINUTO/DWARF1) show multiple subcellular localizations in Arabidopsis thaliana (Heynh) L

    DEFF Research Database (Denmark)

    Silvestro, Daniele; Andersen, Tonni Grube; Schaller, Hubert;

    2013-01-01

    to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map...... of steroidogenic enzymes in cells, the coding regions of ¿(7)-sterol-C(5)-desaturase (STE1/DWARF7), ¿(24)-sterol-¿(24)-reductase (DIMINUTO/DWARF1) and ¿(5,7)-sterol-¿(7)-reductase (DWARF5) were fused to the yellow fluorescent protein (YFP) and transformed into Arabidopsis thaliana mutant lines deficient...... in the corresponding enzymes. All fusion proteins were found to localize in the endoplasmic reticulum in functionally complemented plants. The results show that both ¿(5,7)-sterol-¿(7)-reductase and ¿(24)-sterol-¿(24)-reductase are in addition localized to the plasma membrane, whereas ¿(7)-sterol-C(5)-desaturase...

  15. New method to determine free sterols/oxysterols in food matrices using gas chromatography and ion trap mass spectrometry (GC-IT-MS).

    Science.gov (United States)

    Szterk, Arkadiusz; Pakuła, Lucyna

    2016-05-15

    Sterols/oxysterols in food may be free or bound i.e. esterified with fatty acids. Methods commonly applied to determine those compounds in such matrices (based on various analytical techniques) usually start with hydrolysis of the food lipid fraction, which means that the results are no good indication of concentration of free sterols/oxysterols only. But only free oxysterols are proatherogenic factors, bound ones are not. There are some published methods selectively sensitive to free oxysterols only, but they are capable to determine only a few compounds and feature very low recovery rates. The aim of this work was to develop a method to determine various free (non-esterified) sterols/oxysterols in various food matrices. The developed method is based on the GC-IT-MS technique used in the chemical ionization mode. It was applied to determine 16 different free sterols/oxysterols in egg powder, cheese, butter, milk and salami. Fat extracted from the given matrix is purified on a specially prepared silica-gel bed to separate the sterol fraction from the oxysterol one. Sterols are silylated using N,O-bis(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane BSTFA:TMCS, then GC-IT-MS analysed. The method features high recovery rates (75-95%), high reproducibility (RSD<20%), and sensitivity within the 0.01-0.3 mg 100 g(-1) range, depending on the analysed compound. The method is ideally suited for determination of free sterols/oxysterols. Besides, should total concentration of both free and bound forms be of interest, food lipids may be transesterificated before the silica-gel bed purification step.

  16. Sterols and sphingolipids: Dynamic duo or partners in crime?

    Science.gov (United States)

    Gulati, Sonia; Liu, Ying; Munkacsi, Andrew B.; Wilcox, Lisa; Sturley, Stephen L.

    2010-01-01

    One manner in which eukaryotic cells respond to their environments is by optimizing the composition and proportions of sterols and sphingolipids in membranes. The physical association of the planar ring of sterols with the acyl chains of phospholipids, particularly sphingolipids, produces membrane micro-heterogeneity that is exploited to coordinate several crucial pathways. We hypothesize that these lipid molecules play an integrated role in human disease; when one of the partners is mis-regulated, pathology frequently ensues. Sterols and sphingolipid levels are not coordinated by the action of a single master regulator, however the cross talk between their metabolic pathways is considerable. We describe our perspectives on the key components of synthesis, catabolism and transport of these lipid partners with an emphasis on evolutionarily conserved reactions that produce disease states when defective. PMID:20362613

  17. New Marine Sterols from a Gorgonian Pinnigorgia sp.

    Science.gov (United States)

    Chang, Yu-Chia; Hwang, Tsong-Long; Chao, Chih-Hua; Sung, Ping-Jyun

    2017-03-03

    Continuous chemical investigation of the gorgonian coral Pinnigorgia sp. resulted in the isolation of two new sterols, 5α,6α-epoxy-(22E,24R)-3β,11-dihydroxy-9,11-secoergosta-7-en-9-one (1) and (22R)-acetoxy-(24ξ)-ergosta-5-en-3β,25-diol (2). The structures of sterols 1 and 2 were elucidated using spectroscopic methods. Sterol 1 displayed inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils with IC50 values of 8.65 and 5.86 μM, respectively. The structure of a known metabolite, pubinernoid A (3), is revised as (+)-loliolide (4).

  18. Multicolor bleach-rate imaging enlightens in vivo sterol transport

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Sage, Daniel

    2011-01-01

    ) labelled with GFP-tagged RME-1 (GFP-RME-1) in the intestine of both, wild-type nematodes and mutant animals lacking intestinal gut granules (glo1-mutants). DHE-enriched intestinal organelles of glo1-mutants were decorated with GFPrme8, a marker for early endosomes. No co-localization was found......, dehydroergosterol (DHE) in the genetically tractable model organism Caenorhabditis elegans (C. elegans). DHE is structurally very similar to cholesterol and ergosterol, two sterols used by the sterol-auxotroph nematode. We developed a new computational method measuring fluorophore bleaching kinetics at every pixel...... with a lysosomal marker, GFP-LMP1. Our new methods hold great promise for further studies on endosomal sterol transport in C. elegans....

  19. Differential impact of interferon regulatory factor 7 in the initiation of the type I interferon response in the LCMV infected CNS versus the periphery

    DEFF Research Database (Denmark)

    Christensen, Jeanette Erbo; Fenger, Christina; Issazadeh-Navikas, Shohreh

    2012-01-01

    Interferon (IFN) regulatory factors (IRFs) are a family of transcription factors involved in regulating type I IFN genes and other genes participating in the early antiviral host response. To better understand the mechanisms involved in virus-induced central nervous system (CNS) inflammation, we...

  20. Improvement of livestock breeding strategies using physiologic and functional genomic information of the muscle regulatory factors gene family for skeletal muscle development

    NARCIS (Netherlands)

    Pas, te M.F.W.; Soumillon, A.

    2001-01-01

    A defined number of skeletal muscle fibers are formed in two separate waves during prenatal development, while postnatal growth is restricted to hypertrophic muscle fiber growth. The genes of the MRF (muscle regulatory factors) gene family, consisting of 4 structurally related transcription factors

  1. Identification and characterization of a novel regulatory factor: IgA-inducing protein.

    Science.gov (United States)

    Austin, Amy S; Haas, Karen M; Naugler, Sasha M; Bajer, Anna A; Garcia-Tapia, David; Estes, D Mark

    2003-08-01

    IgA is the predominant Ig isotype in mucosal secretions and thus plays a pivotal role in host defense. The mechanisms by which IgA expression is regulated may differ among species and involve multiple pathways. Various cytokines and costimulators have been identified which regulate expression of this isotype, including IL-10, IL-2, vasoactive intestinal peptide, and TGF-beta. We have tested a wide array of known factors, but only under very limited conditions do these factors mediate substantial IgA production in vitro from bovine B cells. In response to these findings, we generated a cDNA library in a mammalian expression vector from activated cells derived from bovine gut-associated lymphoid tissues (Peyer's patch and mesenteric lymph node cells) as a source of soluble factor(s) that may regulate IgA production. We have identified a novel factor, IgA-inducing protein, which stimulates relatively high levels of IgA production in vitro following CD40 stimulation in coculture with IL-2. Our data suggest that IgA-inducing protein regulates IgA by acting as a switch or differentiation factor and is expressed in a variety of lymphoid and nonlymphoid tissues.

  2. Sterol and genomic analyses validate the sponge biomarker hypothesis.

    Science.gov (United States)

    Gold, David A; Grabenstatter, Jonathan; de Mendoza, Alex; Riesgo, Ana; Ruiz-Trillo, Iñaki; Summons, Roger E

    2016-03-01

    Molecular fossils (or biomarkers) are key to unraveling the deep history of eukaryotes, especially in the absence of traditional fossils. In this regard, the sterane 24-isopropylcholestane has been proposed as a molecular fossil for sponges, and could represent the oldest evidence for animal life. The sterane is found in rocks ∼650-540 million y old, and its sterol precursor (24-isopropylcholesterol, or 24-ipc) is synthesized today by certain sea sponges. However, 24-ipc is also produced in trace amounts by distantly related pelagophyte algae, whereas only a few close relatives of sponges have been assayed for sterols. In this study, we analyzed the sterol and gene repertoires of four taxa (Salpingoeca rosetta, Capsaspora owczarzaki, Sphaeroforma arctica, and Creolimax fragrantissima), which collectively represent the major living animal outgroups. We discovered that all four taxa lack C30 sterols, including 24-ipc. By building phylogenetic trees for key enzymes in 24-ipc biosynthesis, we identified a candidate gene (carbon-24/28 sterol methyltransferase, or SMT) responsible for 24-ipc production. Our results suggest that pelagophytes and sponges independently evolved C30 sterol biosynthesis through clade-specific SMT duplications. Using a molecular clock approach, we demonstrate that the relevant sponge SMT duplication event overlapped with the appearance of 24-isopropylcholestanes in the Neoproterozoic, but that the algal SMT duplication event occurred later in the Phanerozoic. Subsequently, pelagophyte algae and their relatives are an unlikely alternative to sponges as a source of Neoproterozoic 24-isopropylcholestanes, consistent with growing evidence that sponges evolved long before the Cambrian explosion ∼542 million y ago.

  3. Miscibility and interactions of animal and plant sterols with choline plasmalogen in binary and multicomponent model systems.

    Science.gov (United States)

    Hąc-Wydro, Katarzyna; Luty, Katarzyna

    2014-04-01

    In this work miscibility and interactions of sterols with choline plasmalogen (PC-plasm) in Langmuir monolayers were studied. Moreover, the properties of cholesterol/phosphatidylcholine/plasmalogen mixtures of different PC-plasm concentration were investigated. The foregoing systems were treated as a model of cancer cell membranes, which are of higher plasmalogen level than normal cells. Finally, the influence of β-sitosterol and stigmasterol (phytosterols differing in anticancer potency) on these mixtures was verified. The properties of monolayers were analyzed based on the parameters derived from the surface pressure-area isotherms and images taken with Brewster Angle Microscope. It was found that at 30% of sterol in sterol/plasmalogen monolayer the lipids are immiscible and 3D crystallites are formed within the film. Cholesterol molecules mix favorably with PC-plasm at Xchol ≥ 0.5, while the investigated phytosterols only at their prevailing proportion in binary system. The increase of choline plasmalogen in cholesterol/phosphatidylcholine monolayer causes destabilization of the system. Moreover, the incorporation of phytosterols into cholesterol/phosphatidylcholine+PC-plasm mixtures disturbed membrane morphology and this effect was stronger for β-sitosterol as compared to stigmasterol. It was concluded that the presence of vinyl ether bond at sn-1 position in PC-plasm molecule strongly affects miscibility of choline plasmalogen with sterols. The comparison of the collected data with those reported in literature allowed one to conclude that miscibility and interactions of sterols with PC-plasm are less favorable than those with phosphatidylcholine. It was also suggested that overexpression of plasmalogens in cancer cell membranes may be a factor differentiating sensitivity of cells to anticancer effect of phytosterols. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor X (RFX) transcription factors through X-box promoter motifs

    Science.gov (United States)

    Tammimies, Kristiina; Bieder, Andrea; Lauter, Gilbert; Sugiaman-Trapman, Debora; Torchet, Rachel; Hokkanen, Marie-Estelle; Burghoorn, Jan; Castrén, Eero; Kere, Juha; Tapia-Páez, Isabel; Swoboda, Peter

    2016-01-01

    DYX1C1, DCDC2, and KIAA0319 are three of the most replicated dyslexia candidate genes (DCGs). Recently, these DCGs were implicated in functions at the cilium. Here, we investigate the regulation of these DCGs by Regulatory Factor X transcription factors (RFX TFs), a gene family known for transcriptionally regulating ciliary genes. We identify conserved X-box motifs in the promoter regions of DYX1C1, DCDC2, and KIAA0319 and demonstrate their functionality, as well as the ability to recruit RFX TFs using reporter gene and electrophoretic mobility shift assays. Furthermore, we uncover a complex regulation pattern between RFX1, RFX2, and RFX3 and their significant effect on modifying the endogenous expression of DYX1C1 and DCDC2 in a human retinal pigmented epithelial cell line immortalized with hTERT (hTERT-RPE1). In addition, induction of ciliogenesis increases the expression of RFX TFs and DCGs. At the protein level, we show that endogenous DYX1C1 localizes to the base of the cilium, whereas DCDC2 localizes along the entire axoneme of the cilium, thereby validating earlier localization studies using overexpression models. Our results corroborate the emerging role of DCGs in ciliary function and characterize functional noncoding elements, X-box promoter motifs, in DCG promoter regions, which thus can be targeted for mutation screening in dyslexia and ciliopathies associated with these genes.—Tammimies, K., Bieder, A., Lauter, G., Sugiaman-Trapman, D., Torchet, R., Hokkanen, M.-E., Burghoorn, J., Castrén, E., Kere, J., Tapia-Páez, I., Swoboda, P. Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor (RF) X transcription factors through X-box promoter motifs. PMID:27451412

  5. Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor X (RFX) transcription factors through X-box promoter motifs.

    Science.gov (United States)

    Tammimies, Kristiina; Bieder, Andrea; Lauter, Gilbert; Sugiaman-Trapman, Debora; Torchet, Rachel; Hokkanen, Marie-Estelle; Burghoorn, Jan; Castrén, Eero; Kere, Juha; Tapia-Páez, Isabel; Swoboda, Peter

    2016-10-01

    DYX1C1, DCDC2, and KIAA0319 are three of the most replicated dyslexia candidate genes (DCGs). Recently, these DCGs were implicated in functions at the cilium. Here, we investigate the regulation of these DCGs by Regulatory Factor X transcription factors (RFX TFs), a gene family known for transcriptionally regulating ciliary genes. We identify conserved X-box motifs in the promoter regions of DYX1C1, DCDC2, and KIAA0319 and demonstrate their functionality, as well as the ability to recruit RFX TFs using reporter gene and electrophoretic mobility shift assays. Furthermore, we uncover a complex regulation pattern between RFX1, RFX2, and RFX3 and their significant effect on modifying the endogenous expression of DYX1C1 and DCDC2 in a human retinal pigmented epithelial cell line immortalized with hTERT (hTERT-RPE1). In addition, induction of ciliogenesis increases the expression of RFX TFs and DCGs. At the protein level, we show that endogenous DYX1C1 localizes to the base of the cilium, whereas DCDC2 localizes along the entire axoneme of the cilium, thereby validating earlier localization studies using overexpression models. Our results corroborate the emerging role of DCGs in ciliary function and characterize functional noncoding elements, X-box promoter motifs, in DCG promoter regions, which thus can be targeted for mutation screening in dyslexia and ciliopathies associated with these genes.-Tammimies, K., Bieder, A., Lauter, G., Sugiaman-Trapman, D., Torchet, R., Hokkanen, M.-E., Burghoorn, J., Castrén, E., Kere, J., Tapia-Páez, I., Swoboda, P. Ciliary dyslexia candidate genes DYX1C1 and DCDC2 are regulated by Regulatory Factor (RF) X transcription factors through X-box promoter motifs.

  6. Study on sterols from brown algae (Sargassum muticum)

    Institute of Scientific and Technical Information of China (English)

    WANG Peirong; XU Guanjun; BIAN Lizeng; ZHANG Shuichang; SONG Fuqing

    2006-01-01

    Various △5-3β-sterenols, whose carbon numbers range from C19-C23 to C26-C30and some compounds have many stereomers maximal up to six,have been detected out from the extract of brown algae (Sargassum muticum), which means that steranes with lower carbon numbers are likely different in the origin, and some corresponding sterol stereoisomers may have already existed in their precursor organisms. This provides some experimental evidence for supplementing and amending the traditional interpretation of the sterol stereoisomer transformation during the deposition and diagenesis of organic matter.

  7. Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2009-01-01

    Full Text Available Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS, which catalyzes the first committed step in sterol biosynthesis, (d allylamines, inhibitors of squalene epoxidase, (e azoles, which inhibit C14α-demethylase, and (f azasterols, which inhibit Δ24(25-sterol methyltransferase (SMT. Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures, and their effects on protozoan structural organization (as evaluted by light and electron microscopy and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take

  8. Screening of the transcriptional regulatory regions of vascular endothelial growth factor receptor 2 (VEGFR2 in amyotrophic lateral sclerosis

    Directory of Open Access Journals (Sweden)

    Hartley Judith

    2007-04-01

    Full Text Available Abstract Background Vascular endothelial growth factor (VEGF has neurotrophic activity which is mediated by its main agonist receptor, VEGFR2. Dysregulation of VEGF causes motor neurone degeneration in a mouse model of amyotrophic lateral sclerosis (ALS, and expression of VEGFR2 is reduced in motor neurones and spinal cord of patients with ALS. Methods We have screened the promoter region and 4 exonic regions of functional significance of the VEGFR2 gene in a UK population of patients with ALS, for mutations and polymorphisms that may affect expression or function of this VEGF receptor. Results No mutations were identified in the VEGFR2 gene. We found no association between polymorphisms in the regulatory regions of the VEGFR2 gene and ALS. Conclusion Mechanisms other than genetic variation may downregulate expression or function of the VEGFR2 receptor in patients with ALS.

  9. Mga2 transcription factor regulates an oxygen-responsive lipid homeostasis pathway in fission yeast

    DEFF Research Database (Denmark)

    Burr, Risa; Stewart, Emerson V; Shao, Wei

    2016-01-01

    Eukaryotic lipid synthesis is oxygen-dependent with cholesterol synthesis requiring 11 oxygen molecules and fatty acid desaturation requiring 1 oxygen molecule per double bond. Accordingly, organisms evaluate oxygen availability to control lipid homeostasis. The sterol regulatory element......-binding protein (SREBP) transcription factors regulate lipid homeostasis. In mammals, SREBP-2 controls cholesterol biosynthesis, whereas SREBP-1 controls triacylglycerol and glycerophospholipid biosynthesis. In the fission yeast Schizosaccharomyces pombe, the SREBP-2 homolog Sre1 regulates sterol homeostasis....... In the absence of mga2, fission yeast exhibited growth defects under both normoxia and low oxygen conditions. Mga2 transcriptional targets were enriched for lipid metabolism genes, and mga2Δ cells showed disrupted triacylglycerol and glycerophospholipid homeostasis, most notably with an increase in fatty acid...

  10. Influence of the sterol aliphatic side chain on membrane properties: a molecular dynamics study.

    Science.gov (United States)

    Robalo, João R; Ramalho, J P Prates; Huster, Daniel; Loura, Luís M S

    2015-09-21

    Following a recent experimental investigation of the effect of the length of the alkyl side chain in a series of cholesterol analogues (Angew. Chem., Int. Ed., 2013, 52, 12848-12851), we report here an atomistic molecular dynamics characterization of the behaviour of methyl-branched side chain sterols (iso series) in POPC bilayers. The studied sterols included androstenol (i-C0-sterol) and cholesterol (i-C8-sterol), as well as four other derivatives (i-C5, i-C10, i-C12 and i-C14-sterol). For each sterol, both subtle local effects and more substantial differential alterations of membrane properties along the iso series were investigated. The location and orientation of the tetracyclic ring system is almost identical in all compounds. Among all the studied sterols, cholesterol is the sterol that presents the best matching with the hydrophobic length of POPC acyl chains, whereas longer-chained sterols interdigitate into the opposing membrane leaflet. In accordance with the experimental observations, a maximal ordering effect is observed for intermediate sterol chain length (i-C5, cholesterol, i-C10). Only for these sterols a preferential interaction with the saturated sn-1 chain of POPC (compared to the unsaturated sn-2 chain) was observed, but not for either shorter or longer-chained derivatives. This work highlights the importance of the sterol alkyl chain in the modulation of membrane properties and lateral organization in biological membranes.

  11. Efficacy and safety of plant stanols and sterols in the control of blood cholesterol levels

    NARCIS (Netherlands)

    Katan, M.B.; Grundy, S.M.; Jones, P.J.H.; Law, M.R.; Miettinen, T.; Paoletti, R.

    2003-01-01

    Foods with plant stanol or sterol esters lower serum cholesterol levels. We summarize the deliberations of 32 experts on the efficacy and safety of sterols and stanols. A meta-analysis of 41 trials showed that intake of 2 g/d of stanols or sterols reduced low-density lipoprotein (LDL) by 10%; higher

  12. 4-Methyl Sterols Regulate Fission Yeast SREBP-Scap under Low Oxygen and Cell Stress*

    Science.gov (United States)

    Hughes, Adam L.; Lee, Chih-Yung S.; Bien, Clara M.; Espenshade, Peter J.

    2008-01-01

    In fission yeast, orthologs of mammalian SREBP and Scap, called Sre1 and Scp1, monitor oxygen-dependent sterol synthesis as a measure of cellular oxygen supply. Under low oxygen conditions, sterol synthesis is inhibited and Sre1 cleavage is activated. However, the sterol signal for Sre1 activation is unknown. In this study, we characterize the sterol signal for Sre1 activation using a combination of Sre1 cleavage assays and gas chromatography sterol analysis. We find that Sre1 activation is regulated by levels of the 4-methyl sterols 24-methylene lanosterol and 4,4-dimethylfecosterol under conditions of low oxygen and cell stress. Both increases and decreases in the level of these ergosterol pathway intermediates induce Sre1 proteolysis in a Scp1-dependent manner. The SREBP ortholog in the pathogenic fungus Cryptococcus neoformans is also activated by high levels of 4-methyl sterols, suggesting that this signal for SREBP activation is conserved among unicellular eukaryotes. Finally, we provide evidence that the sterol sensing domain of Scp1 is important for regulating Sre1 proteolysis. The conserved mutations Y247C, L264F, and D392N in Scp1 that render Scap insensitive to sterols cause constitutive Sre1 activation. These findings indicate that unlike Scap, fission yeast Scp1 responds to 4-methyl sterols and thus shares properties with mammalian HMG-CoA reductase, a sterol sensing domain protein whose degradation is regulated by the 4-methyl sterol lanosterol. PMID:17595166

  13. Plant sterol metabolism. Δ(7-Sterol-C5-desaturase (STE1/DWARF7, Δ(5,7-sterol-Δ(7-reductase (DWARF5 and Δ(24-sterol-Δ(24-reductase (DIMINUTO/DWARF1 show multiple subcellular localizations in Arabidopsis thaliana (Heynh L.

    Directory of Open Access Journals (Sweden)

    Daniele Silvestro

    Full Text Available Sterols are crucial lipid components that regulate membrane permeability and fluidity and are the precursors of bioactive steroids. The plant sterols exist as three major forms, free sterols, steryl glycosides and steryl esters. The storage of steryl esters in lipid droplets has been shown to contribute to cellular sterol homeostasis. To further document cellular aspects of sterol biosynthesis in plants, we addressed the question of the subcellular localization of the enzymes implicated in the final steps of the post-squalene biosynthetic pathway. In order to create a clear localization map of steroidogenic enzymes in cells, the coding regions of Δ(7-sterol-C(5-desaturase (STE1/DWARF7, Δ(24-sterol-Δ(24-reductase (DIMINUTO/DWARF1 and Δ(5,7-sterol-Δ(7-reductase (DWARF5 were fused to the yellow fluorescent protein (YFP and transformed into Arabidopsis thaliana mutant lines deficient in the corresponding enzymes. All fusion proteins were found to localize in the endoplasmic reticulum in functionally complemented plants. The results show that both Δ(5,7-sterol-Δ(7-reductase and Δ(24-sterol-Δ(24-reductase are in addition localized to the plasma membrane, whereas Δ(7-sterol-C(5-desaturase was clearly detected in lipid particles. These findings raise new challenging questions about the spatial and dynamic cellular organization of sterol biosynthesis in plants.

  14. Transcription Factor Binding Probabilities in Orthologous Promoters: An Alignment-Free Approach to the Inference of Functional Regulatory Targets

    Science.gov (United States)

    Liu, Xiao; Clarke, Neil D.

    Using a physically principled method of scoring genomic sequences for the potential to be bound by transcription factors, we have developed an algorithm for assessing the conservation of predicted binding occupancy that does not rely on sequence alignment of promoters. The method, which we call ortholog-weighting, assesses the degree to which the predicted binding occupancy of a transcription factor in a reference gene is also predicted in the promoters of orthologous genes. The analysis was performed separately for over 100 different transcription factors in S. cerevisiae. Statistical significance was evaluated by simulation using permuted versions of the position weight matrices. Ortholog-weighting produced about twice as many significantly high scoring genes as were obtained from the S. cerevisiae genome alone. Gene Ontology analysis found a similar two-fold enrichment of genes. Both analyses suggest that ortholog-weighting improves the prediction of true regulatory targets. Interestingly, the method has only a marginal effect on the prediction of binding by chromatin immunoprecipitation (ChIP) assays. We suggest several possibilities for reconciling this result with the improved enrichment that we observe for functionally related promoters and for promoters that are under positive selection.

  15. Expression Pattern of Myogenic Regulatory Transcription Factor mRNAs in the Embryo and Adult Labeo rohita (Hamilton, 1822

    Directory of Open Access Journals (Sweden)

    Archya Sengupta

    2014-01-01

    Full Text Available Understanding the regulation of skeletal muscle development is important to meet the increasing demand of Indian major carp Labeo rohita. Myogenic regulatory factors (MRFs along with myocyte specific enhancer factor 2 (MEF2 play the pivotal role in the determination and differentiation of skeletal muscle. The majority of skeletal muscle genes require both MRFs and MEF2 family members to activate their transcription. In this study, the expression pattern of MyoD, myf-5, myogenin, and MEF2A was observed from 6 h after fertilization to 12 months of age using semiquantitative RT-PCR as well as real-time PCR method. MyoD and myf-5 mRNAs were expressed at high level at the early embryonic stages. Myogenin and MEF2A were expressed after MyoD and myf-5 and remained active up to adult stage. Expression of MyoD was lower than that of Myf-5 after the 5th month. Partial sequencing of MyoD, myf-5, and MEF2A was done to draw phylogeny. In phylogenetic study, Labeo MyoD, MEF2A and myf-5 were found to be closely related to those of common carp. The present investigation suggests that the four transcription factors play pivotal role in the regulation of muscle growth of Labeo rohita in an overlapping and interconnected way.

  16. Beta-catenin regulates myogenesis by relieving I-mfa-mediated suppression of myogenic regulatory factors in P19 cells.

    Science.gov (United States)

    Pan, Weijun; Jia, Yingying; Wang, Jiyong; Tao, Donglei; Gan, Xiaoqing; Tsiokas, Leonidas; Jing, Naihe; Wu, Dianqing; Li, Lin

    2005-11-29

    Wnt/beta-catenin signaling plays a critical role in embryonic myogenesis. Here we show that, in P19 embryonic carcinoma stem cells, Wnt/beta-catenin signaling initiates the myogenic process depends on beta-catenin-mediated relief of I-mfa (inhibitor of MyoD Family a) suppression of myogenic regulatory factors (MRFs). We found that beta-catenin interacted with I-mfa and that the interaction was enhanced by Wnt3a. In addition, we found that the interaction between beta-catenin and I-mfa was able to attenuate the interaction of I-mfa with MRFs, relieve I-mfa-mediated suppression of the transcriptional activity and cytosolic sequestration of MRFs, and initiate myogenesis in a P19 myogenic model system that expresses exogenous myogenin. This work reveals a mechanism for the regulation of MRFs during myogenesis by elucidating a beta-catenin-mediated, but lymphoid enhancing factor-1/T cell factor independent, mechanism in regulation of myogenic fate specification and differentiation of P19 mouse stem cells.

  17. Regulatory and Functional Connection of Microphthalmia-Associated Transcription Factor and Anti-Metastatic Pigment Epithelium Derived Factor in Melanoma

    Directory of Open Access Journals (Sweden)

    Asunción Fernández-Barral

    2014-06-01

    Full Text Available Pigment epithelium-derived factor (PEDF, a member of the serine protease inhibitor superfamily, has potent anti-metastatic effects in cutaneous melanoma through its direct actions on endothelial and melanoma cells. Here we show that PEDF expression positively correlates with microphthalmia-associated transcription factor (MITF in melanoma cell lines and human samples. High PEDF and MITF expression is characteristic of low aggressive melanomas classified according to molecular and pathological criteria, whereas both factors are decreased in senescent melanocytes and naevi. Importantly, MITF silencing down-regulates PEDF expression in melanoma cell lines and primary melanocytes, suggesting that the correlation in the expression reflects a causal relationship. In agreement, analysis of Chromatin immunoprecipitation coupled to high throughput sequencing (ChIP-seq data sets revealed three MITF binding regions within the first intron of SERPINF1, and reporter assays demonstrated that the binding of MITF to these regions is sufficient to drive transcription. Finally, we demonstrate that exogenous PEDF expression efficiently halts in vitro migration and invasion, as well as in vivo dissemination of melanoma cells induced by MITF silencing. In summary, these results identify PEDF as a novel transcriptional target of MITF and support a relevant functional role for the MITF-PEDF axis in the biology of melanoma.

  18. Regulatory roles of tumor necrosis factor alpha-induced proteins (TNFAIPs) 3 and 9 in arthritis.

    Science.gov (United States)

    Matsumoto, Isao; Inoue, Asuka; Takai, Chinatsu; Umeda, Naoto; Tanaka, Yuki; Kurashima, Yuko; Sumida, Takayuki

    2014-07-01

    Tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) have proved to be important in rheumatoid arthritis (RA) because the outcome of RA has greatly improved with the recent availability of biologics targeting them. It is well accepted that these cytokines are involved in the activation of the nuclear factor-κB (NF-κB) signaling pathway, but our understanding of the dependency of these pro-inflammatory cytokines and the link between them in RA is currently limited. Recently, we and others proved the importance of TNFα-induced protein (TNFAIP), due to the spontaneous development of arthritis in deficient animals that are dependent on IL-6. To date, nine TNFAIPs have been identified, and TNFAIP3 and TNFAIP9 were found to be clearly associated with mouse and human arthritis. In this review, we compare and discuss recent TNFAIP topics, especially focusing on TNFAIP3 and TNFAIP9 in autoimmune arthritis in mice and humans.

  19. Relationship between Helicobacter pylori virulence factors and regulatory cytokines as predictors of clinical outcome

    Science.gov (United States)

    Serrano, Carolina; Diaz, Maria Ines; Valdivia, Alejandra; Godoy, Alex; Peña, Alfredo; Rollan, Antonio; Kirberg, Arturo; Hebel, Eduardo; Fierro, Jaqueline; Klapp, Gerardo; Venegas, Alejandro; Harris, Paul R.

    2013-01-01

    H. pylori infection is highly prevalent in Chile (73%). Usually a minority of infected patients develops complications such as ulcers and gastric cancer that have been associated with the presence of virulence factors (cagA, vacA) and host T helper response (Th1/Th2). Our aim was to evaluate the relationship between strain virulence and host immune response, using a multiple regression approach for the development of a model based on data collected from H. pylori infected patients in Chile. We analyzed levels of selected cytokines determined by ELISA (IL-12, IL-10, IFN-γ and IL-4) and the presence of cagA and vacA alleles polymorphisms determined by PCR in antral biopsies of 41 patients referred to endoscopy. By multiple regression analysis we established a correlation between bacterial and host factors using clinical outcome (gastritis and duodenal ulcer) as dependent variables. The selected model was described by: clinical outcome = 0.867491 (cagA) + 0.0131847 (IL-12/IL-10) + 0.0103503 (IFN-γ/IL-4) and it was able to explain over 90% of clinical outcomes observations (R2=96.4). This model considers that clinical outcomes are better explained by the interaction of host immune factors and strain virulence as a complex and interdependent mechanism. PMID:17336120

  20. Regulatory role of DREB transcription factors in plant drought, salt and cold tolerance

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    rd29A gene of Arabidopsis encodes a LEA-like hydrophilic protein, its expression is induced by drought, high-salt and cold stress. In the promoter region of rd29A gene, there are 2 DRE cis-acting elements involved in responses to these environmental stresses. 5 cDNAs (DREB1A~C and DREB2A~B) encoding DREB transcription factors, which specifically bind to DRE element and control the expression of reporter gene under drought, high-salt and stress, have been isolated by One-Hybrid screening method and with DRE element of rd29A promoter. DREB transcription factors and DRE element function in signal transduction of drought, high-salt and cold stress. One DREB transcription factor can control the expression of several target functional genes involved in plant tolerance to drought, high-salt and cold stress. Thus, it may be an effective strategy to achieve ideal, multiple and fundamental effect for improving plant stress-resistance by DREB gene transfer.

  1. EXPRESSION OF HYPOXIA INDUCIBLE FACTOR-1α AND ITS REGULATORY ROLE IN DEVELOPING VERTEBRAE

    Institute of Scientific and Technical Information of China (English)

    ZHU Xun-bing; DENG Lian-fu; XIAO Yu-zhou

    2009-01-01

    Objective To explore the expression pattern and possible role of hypoxia inducible factor-1α(HIF-1α) in fetal vertebrae development of mouse.Methods The developmental stages of mice fetal vertebrae were observed from embryonic days 13.5 to 18.5 (E13.5 to E18.5) by stereoscopic and light microscopes respectively, and the expressions of HIF-1α at various times were also detected at levels of mRNA and protein by using methods of RT-PCR and Western blotting. Distribution of HIF-1α in the vertebrae was examined by immunohistochemical assay. Vascular endothelia growth factor (VEGF) mRNA and other chondro-osteoblast marker genes as type Ⅱ collagen a1 (Coll2a1) and osteocalcin (OCN) were detected by RT-PCR too.Results The cartilaginous spine column began to form at E13.5, followed by the arising of the primary ossification center in vertebrae at E15.5, then the osteogenesis expanded and extended to both sides of the vertebrae. HIF-1α mRNA began to express at E13.5, and showed significantly higher level at E14.5 (P<0.05), then declined to a low level. VEGF mRNA expressed coincidently with HIF-1α. While HIF-1α protein expression was observed at E14.5 and lasted at low level till to birth. The expression pattern of Coll2a1 and OCN elucidated the cell evolution from chondrocyte to osteoblast.Conclusion The developmental pattern of vertebrae appears to be an endochondral osteogenesis process. Existed hypoxia microenviroment in the vertebrae may increase HIF-1α mRNA and protein contents thus activate VEGF expression, as may be related to the activation of other downstream genes of hypoxia inducible factor-1α and initiate the cascade of endochondral osteogenesis.

  2. Free Sterols of the red alga Chondria armata (Kutz.) Okamura

    Digital Repository Service at National Institute of Oceanography (India)

    Govenkar, M.B.; Wahidullah, S.

    The free sterols of the red alga, Chondria armata have been identified by means of NMR, EIMS and GCMS analyses. The mixture contained besides cholesterol, C sub(28) and C sub(29) saturated as well as unsaturated components. The major component...

  3. Minor sterols from the sponge Ircinia ramosa (Killer)

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Naik, C.G.; Das, B.; Kamat, S.Y.

    Three sterols, isolated from the lipid fraction of the sponge Ircinia ramosa were characterised as cholest-5-en-3 beta-ol-7-one (7-oxo cholesterol, 1), cholest 5-23-dien-b beta ol-7-one (7-oxo demosterol, 2) and 24E-ethyl cholest-5-en-3 beta -ol-7...

  4. Shotgun lipidomic analysis of chemically sulfated sterols compromises analytical sensitivity

    DEFF Research Database (Denmark)

    Casanovas, Albert; Hannibal-Bach, Hans Kristian; Jensen, Ole Nørregaard

    2014-01-01

    Fourier transform mass spectrometry (FTMS) for identification and quantification of lipid species [6]. Shotgun lipidomics affords extensive lipidome coverage by combining the analysis of lipid extracts in positive and negative ion mode [1, 3]. Notably, sterols such as cholesterol and ergosterol exhibit...

  5. Sterols from the Lakshadweep sponge, Ircinia ramosa (Killer)

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Naik, C.G.; Das, B.; Kamat, S.Y.

    Four monohydroxy sterols, viz, (22E,24S)-24-methylcholest-5,22-dien-3(beta)-ol (3), cholesterol (4), 24(Xi)-ethylcholesterol (8) and the corresponding Delta super(4)-3 ketones, viz. (22E,24S)-24-methylcholest-4,22-dien-3-one (1), cholest-4-en-3-one...

  6. An Abietane Diterpene and a Sterol from Fungus Phellinus igniarius

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new abietane diterpene 12-hydroxy-7-oxo-5, 8, 11, 13-tetraene-18, 6-abietanolide,together with a new natural sterol stigmasta-7, 22-diene-3β, 5α, 6α-triol have been isolated from the fruiting body of the fungus Phellinus igniarius. Their structures were elucidated by spectroscopic methods including 2D NMR techniques.

  7. Cuf2 Is a Novel Meiosis-Specific Regulatory Factor of Meiosis Maturation

    Science.gov (United States)

    Ioannoni, Raphael; Beaudoin, Jude; Lopez-Maury, Luis; Codlin, Sandra; Bahler, Jurg; Labbe, Simon

    2012-01-01

    Background Meiosis is the specialized form of the cell cycle by which diploid cells produce the haploid gametes required for sexual reproduction. Initiation and progression through meiosis requires that the expression of the meiotic genes is precisely controlled so as to provide the correct gene products at the correct times. During meiosis, four temporal gene clusters are either induced or repressed by a cascade of transcription factors. Principal Findings In this report a novel copper-fist-type regulator, Cuf2, is shown to be expressed exclusively during meiosis. The expression profile of the cuf2+ mRNA revealed that it was induced during middle-phase meiosis. Both cuf2+ mRNA and protein levels are unregulated by copper addition or starvation. The transcription of cuf2+ required the presence of a functional mei4+ gene encoding a key transcription factor that activates the expression of numerous middle meiotic genes. Microscopic analyses of cells expressing a functional Cuf2-GFP protein revealed that Cuf2 co-localized with both homologous chromosomes and sister chromatids during the meiotic divisions. Cells lacking Cuf2 showed an elevated and sustained expression of several of the middle meiotic genes that persisted even during late meiosis. Moreover, cells carrying disrupted cuf2Δ/cuf2Δ alleles displayed an abnormal morphology of the forespore membranes and a dramatic reduction of spore viability. Significance Collectively, the results revealed that Cuf2 functions in the timely repression of the middle-phase genes during meiotic differentiation. PMID:22558440

  8. A model for genetic and epigenetic regulatory networks identifies rare pathways for transcription factor induced pluripotency

    Science.gov (United States)

    Artyomov, Maxim; Meissner, Alex; Chakraborty, Arup

    2010-03-01

    Most cells in an organism have the same DNA. Yet, different cell types express different proteins and carry out different functions. This is because of epigenetic differences; i.e., DNA in different cell types is packaged distinctly, making it hard to express certain genes while facilitating the expression of others. During development, upon receipt of appropriate cues, pluripotent embryonic stem cells differentiate into diverse cell types that make up the organism (e.g., a human). There has long been an effort to make this process go backward -- i.e., reprogram a differentiated cell (e.g., a skin cell) to pluripotent status. Recently, this has been achieved by transfecting certain transcription factors into differentiated cells. This method does not use embryonic material and promises the development of patient-specific regenerative medicine, but it is inefficient. The mechanisms that make reprogramming rare, or even possible, are poorly understood. We have developed the first computational model of transcription factor-induced reprogramming. Results obtained from the model are consistent with diverse observations, and identify the rare pathways that allow reprogramming to occur. If validated, our model could be further developed to design optimal strategies for reprogramming and shed light on basic questions in biology.

  9. IFN regulatory factor 8 is a key constitutive determinant of the morphological and molecular properties of microglia in the CNS.

    Directory of Open Access Journals (Sweden)

    Carsten Minten

    Full Text Available IFN regulatory factor (IRF 8 is a transcription factor that has a key role in the cellular response to IFN-γ and is pivotal in myeloid cell differentiation. Whether IRF8 plays a role in the development and function of microglia, the tissue-resident myeloid cells of the brain, is unknown. Here, we show IRF8 is a constitutively produced nuclear factor in microglia, which suggested that IRF8 might also be a key homeostatic transcriptional determinant of the microglial cell phenotype. In support of this, in mice with a targeted disruption of the IRF8 gene, microglia were increased in number and showed gross alterations in morphology and surface area. In situ analysis of some key myeloid markers revealed that IRF8-deficient microglia had significantly reduced levels of Iba1, but increased levels of CD206 (mannose receptor and F4/80 as well as increased tomato lectin binding. Analysis of microglia ex vivo revealed IRF8-deficient microglia had significantly increased levels of CD45, CD11b and F4/80, but significantly decreased levels of the chemokine receptors CCR2, CCR5 and CX3CR1. The known involvement of some of these molecular markers in membrane dynamics and phagocytosis led us to examine the phagocytic capacity of cultured IRF8-deficient microglia, however, this was found to be similar to wild type microglia. We conclude IRF8 is a constitutively produced nuclear factor in resident microglia of the CNS being a crucial transcriptional determinant of the phenotype of these cells in the healthy brain.

  10. Cuf2 is a novel meiosis-specific regulatory factor of meiosis maturation.

    Directory of Open Access Journals (Sweden)

    Raphael Ioannoni

    Full Text Available BACKGROUND: Meiosis is the specialized form of the cell cycle by which diploid cells produce the haploid gametes required for sexual reproduction. Initiation and progression through meiosis requires that the expression of the meiotic genes is precisely controlled so as to provide the correct gene products at the correct times. During meiosis, four temporal gene clusters are either induced or repressed by a cascade of transcription factors. PRINCIPAL FINDINGS: In this report a novel copper-fist-type regulator, Cuf2, is shown to be expressed exclusively during meiosis. The expression profile of the cuf2(+ mRNA revealed that it was induced during middle-phase meiosis. Both cuf2(+ mRNA and protein levels are unregulated by copper addition or starvation. The transcription of cuf2(+ required the presence of a functional mei4(+ gene encoding a key transcription factor that activates the expression of numerous middle meiotic genes. Microscopic analyses of cells expressing a functional Cuf2-GFP protein revealed that Cuf2 co-localized with both homologous chromosomes and sister chromatids during the meiotic divisions. Cells lacking Cuf2 showed an elevated and sustained expression of several of the middle meiotic genes that persisted even during late meiosis. Moreover, cells carrying disrupted cuf2Δ/cuf2Δ alleles displayed an abnormal morphology of the forespore membranes and a dramatic reduction of spore viability. SIGNIFICANCE: Collectively, the results revealed that Cuf2 functions in the timely repression of the middle-phase genes during meiotic differentiation.

  11. Characterization of flounder ( Paralichthys olivaceus) FoxD5 and its function in regulating myogenic regulatory factor

    Science.gov (United States)

    Tan, Xungang; Zhang, Yuqing; Sun, Wei; Zhang, Peijun; Xu, Yongli

    2012-03-01

    As one member of winged helix domain transcription factors, FoxD5 was reported to be a trunk organizer. Recent study showed that zebrafish foxd5 is expressed in the somites. To further understand the function of FoxD5 in fish muscle development, the FoxD5 gene was isolated from flounder. Its expression pattern was analyzed by in situ hybridization, while its function in regulating myogenic regulatory factor, MyoD, was analyzed by ectopic expression. It showed that flounder FoxD5 was firstly expressed in the tailbud, adaxial cells, and neural plate of the head. In flounder embryo, FoxD5 is expressed not only in forebrain but also in somite cells that will form muscle in the future. When flounder FoxD5 was over-expressed in zebrafish by microinjection, the expression of zebrafish MyoD in the somites was reduced, suggesting that FoxD5 is involved in myogenesis by regulating the expression of MyoD.

  12. A regulatory pathway, ecdysone-transcription factor relish-cathepsin L, is involved in insect fat body dissociation.

    Directory of Open Access Journals (Sweden)

    Yao Zhang

    Full Text Available Insect fat body is the organ for intermediary metabolism, comparable to vertebrate liver and adipose tissue. Larval fat body is disintegrated to individual fat body cells and then adult fat body is remodeled at the pupal stage. However, little is known about the dissociation mechanism. We find that the moth Helicoverpa armigera cathepsin L (Har-CL is expressed heavily in the fat body and is released from fat body cells into the extracellular matrix. The inhibitor and RNAi experiments demonstrate that Har-CL functions in the fat body dissociation in H. armigera. Further, a nuclear protein is identified to be transcription factor Har-Relish, which was found in insect immune response and specifically binds to the promoter of Har-CL gene to regulate its activity. Har-Relish also responds to the steroid hormone ecdysone. Thus, the dissociation of the larval fat body is involved in the hormone (ecdysone-transcription factor (Relish-target gene (cathepsin L regulatory pathway.

  13. HIV-1, interferon and the interferon regulatory factor system: an interplay between induction, antiviral responses and viral evasion.

    Science.gov (United States)

    Marsili, Giulia; Remoli, Anna Lisa; Sgarbanti, Marco; Perrotti, Edvige; Fragale, Alessandra; Battistini, Angela

    2012-01-01

    Thirty years after the first isolation of the etiological agent of AIDS, the virus HIV-1 is still a major threat worldwide with millions of individuals currently infected. Although current combination therapies allow viral replication to be controlled, HIV-1 is not eradicated and persists in drug- and immune system-insensitive reservoirs and a cure is still lacking. Pathogens such as HIV-1 that cause chronic infections are able to adapt to the host in a manner that ensures long term residence and survival, via the evolution of numerous mechanisms that evade various aspects of the innate and adaptive immune response. One such mechanism is targeted to members of the interferon (IFN) regulatory factor (IRF) family of proteins. These transcription factors regulate a variety of biological processes including interferon induction, immune cell activation and downstream pattern recognition receptors (PRRs). HIV-1 renders IRFs harmless and hijacks them to its own advantage in order to facilitate its replication and evasion of immune responses. Type I interferon (IFN), the canonical antiviral innate response, can be induced in both acute and chronic HIV-1 infection in vivo, but in the majority of individuals this initial response is not protective and can contribute to disease progression. Type I IFN expression is largely inhibited in T cells and macrophages in order to successfully establish productive infection, whereas sustained IFN production by plasmacytoid dendritic cells is considered an important source of chronic immune activation, a hallmark to AIDS progression.

  14. Molecular effects of autoimmune-risk promoter polymorphisms on expression, exon choice, and translational efficiency of interferon regulatory factor 5.

    Science.gov (United States)

    Clark, Daniel N; Lambert, Jared P; Till, Rodney E; Argueta, Lissenya B; Greenhalgh, Kathryn E; Henrie, Brandon; Bills, Trieste; Hawkley, Tyson F; Roznik, Marinya G; Sloan, Jason M; Mayhew, Vera; Woodland, Loc; Nelson, Eric P; Tsai, Meng-Hsuan; Poole, Brian D

    2014-05-01

    The rs2004640 single nucleotide polymorphism and the CGGGG copy-number variant (rs77571059) are promoter polymorphisms within interferon regulatory factor 5 (IRF5). They have been implicated as susceptibility factors for several autoimmune diseases. IRF5 uses alternative promoter splicing, where any of 4 first exons begin the mRNA. The CGGGG indel is in exon 1A's promoter; the rs2004640 allele creates a splicing recognition site, enabling usage of exon 1B. This study aimed at characterizing alterations in IRF5 mRNA due to these polymorphisms. Cells with risk polymorphisms exhibited ~2-fold higher levels of IRF5 mRNA and protein, but demonstrated no change in mRNA stability. Quantitative PCR demonstrated decreased usage of exons 1C and 1D in cell lines with the risk polymorphisms. RNA folding analysis revealed a hairpin in exon 1B; mutational analysis showed that the hairpin shape decreased translation 5-fold. Although translation of mRNA that uses exon 1B is low due to a hairpin, increased IRF5 mRNA levels in individuals with the rs2004640 risk allele lead to higher overall protein expression. In addition, several new splice variants of IRF5 were sequenced. IRF5's promoter polymorphisms alter first exon usage and increase transcription levels. High levels of IRF5 may bias the immune system toward autoimmunity.

  15. Different papillomaviruses have different repertoires of transcription factor binding sites: convergence and divergence in the upstream regulatory region

    Directory of Open Access Journals (Sweden)

    Alonso Ángel

    2006-03-01

    Full Text Available Abstract Background Papillomaviruses (PVs infect stratified squamous epithelia in warm-blooded vertebrates and have undergone a complex evolutionary process. The control of the expression of the early ORFs in PVs depends on the binding of cellular and viral transcription factors to the upstream regulatory region (URR of the virus. It is believed that there is a core of transcription factor binding sites (TFBS common to all PVs, with additional individual differences, although most of the available information focuses only on a handful of viruses. Results We have studied the URR of sixty-one PVs, covering twenty different hosts. We have predicted the TFBS present in the URR and analysed these results by principal component analysis and genetic algorithms. The number and nature of TFBS in the URR might be much broader than thus far described, and different PVs have different repertoires of TFBS. Conclusion There are common fingerprints in the URR in PVs that infect primates, although the ancestors of these viruses diverged a long time ago. Additionally, there are obvious differences between the URR of alpha and beta PVs, despite these PVs infect similar histological cell types in the same host, i.e. human. A thorough analysis of the TFBS in the URR might provide crucial information about the differential biology of cancer-associated PVs.

  16. Increased plant sterol and stanol levels in brain of Watanabe rabbits fed rapeseed oil derived plant sterol or stanol esters

    DEFF Research Database (Denmark)

    Fricke, Christiane B.; Schrøder, Malene; Poulsen, Morten

    2007-01-01

    of these components in brain tissue of homozygous and heterozygous Watanabe rabbits, an animal model for familial hypercholesterolemia. Homozygous animals received either a standard diet, RSO stanol or RSO sterol ester while heterozygous animals were additionally fed with 2 g cholesterol/kg to the respective diet...

  17. Endogenous Purification Reveals GREB1 as a Key Estrogen Receptor Regulatory Factor

    Directory of Open Access Journals (Sweden)

    Hisham Mohammed

    2013-02-01

    Full Text Available Estrogen receptor-α (ER is the driving transcription factor in most breast cancers, and its associated proteins can influence drug response, but direct methods for identifying interacting proteins have been limited. We purified endogenous ER using an approach termed RIME (rapid immunoprecipitation mass spectrometry of endogenous proteins and discovered the interactome under agonist- and antagonist-liganded conditions in breast cancer cells, revealing transcriptional networks in breast cancer. The most estrogen-enriched ER interactor is GREB1, a potential clinical biomarker with no known function. GREB1 is shown to be a chromatin-bound ER coactivator and is essential for ER-mediated transcription, because it stabilizes interactions between ER and additional cofactors. We show a GREB1-ER interaction in three xenograft tumors, and using a directed protein-protein approach, we find GREB1-ER interactions in half of ER+ primary breast cancers. This finding is supported by histological expression of GREB1, which shows that GREB1 is expressed in half of ER+ cancers, and predicts good clinical outcome. These findings reveal an unexpected role for GREB1 as an estrogen-specific ER cofactor that is expressed in drug-sensitive contexts.

  18. Uncovering early response of gene regulatory networks in ES cells by systematic induction of transcription factors

    Science.gov (United States)

    Nishiyama, Akira; Xin, Li; Sharov, Alexei A.; Thomas, Marshall; Mowrer, Gregory; Meyers, Emily; Piao, Yulan; Mehta, Samir; Yee, Sarah; Nakatake, Yuhki; Stagg, Carole; Sharova, Lioudmila; Correa-Cerro, Lina S.; Bassey, Uwem; Hoang, Hien; Kim, Eugene; Tapnio, Richard; Qian, Yong; Dudekula, Dawood; Zalzman, Michal; Li, Manxiang; Falco, Geppino; Yang, Hsih-Te; Lee, Sung-Lim; Monti, Manuela; Stanghellini, Ilaria; Islam, Md. Nurul; Nagaraja, Ramaiah; Goldberg, Ilya; Wang, Weidong; Longo, Dan L.; Schlessinger, David; Ko, Minoru S. H.

    2009-01-01

    SUMMARY To examine transcription factor (TF) network(s), we created mouse ES cell lines, in each of which one of 50 TFs tagged with a FLAG moiety is inserted into a ubiquitously controllable tetracycline-repressible locus. Of the 50 TFs, Cdx2 provoked the most extensive transcriptome perturbation in ES cells, followed by Esx1, Sox9, Tcf3, Klf4, and Gata3. ChIP-Seq revealed that CDX2 binds to promoters of up-regulated target genes. By contrast, genes down-regulated by CDX2 did not show CDX2 binding, but were enriched with binding sites for POU5F1, SOX2, and NANOG. Genes with binding sites for these core TFs were also down-regulated by the induction of at least 15 other TFs, suggesting a common initial step for ES cell differentiation mediated by interference with the binding of core TFs to their target genes. These ES cell lines provide a fundamental resource to study biological networks in ES cells and mice. PMID:19796622

  19. Discovery of transcription factors and regulatory regions driving in vivo tumor development by ATAC-seq and FAIRE-seq open chromatin profiling.

    Directory of Open Access Journals (Sweden)

    Kristofer Davie

    2015-02-01

    Full Text Available Genomic enhancers regulate spatio-temporal gene expression by recruiting specific combinations of transcription factors (TFs. When TFs are bound to active regulatory regions, they displace canonical nucleosomes, making these regions biochemically detectable as nucleosome-depleted regions or accessible/open chromatin. Here we ask whether open chromatin profiling can be used to identify the entire repertoire of active promoters and enhancers underlying tissue-specific gene expression during normal development and oncogenesis in vivo. To this end, we first compare two different approaches to detect open chromatin in vivo using the Drosophila eye primordium as a model system: FAIRE-seq, based on physical separation of open versus closed chromatin; and ATAC-seq, based on preferential integration of a transposon into open chromatin. We find that both methods reproducibly capture the tissue-specific chromatin activity of regulatory regions, including promoters, enhancers, and insulators. Using both techniques, we screened for regulatory regions that become ectopically active during Ras-dependent oncogenesis, and identified 3778 regions that become (over-activated during tumor development. Next, we applied motif discovery to search for candidate transcription factors that could bind these regions and identified AP-1 and Stat92E as key regulators. We validated the importance of Stat92E in the development of the tumors by introducing a loss of function Stat92E mutant, which was sufficient to rescue the tumor phenotype. Additionally we tested if the predicted Stat92E responsive regulatory regions are genuine, using ectopic induction of JAK/STAT signaling in developing eye discs, and observed that similar chromatin changes indeed occurred. Finally, we determine that these are functionally significant regulatory changes, as nearby target genes are up- or down-regulated. In conclusion, we show that FAIRE-seq and ATAC-seq based open chromatin profiling

  20. EXO70C2 is a key regulatory factor for optimal tip growth of pollen

    KAUST Repository

    Synek, Lukas

    2017-03-30

    The exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.

  1. Basolateral Na+/HCO3– cotransport activity is regulated by the dissociable Na+/H+ exchanger regulatory factor

    Science.gov (United States)

    Bernardo, Angelito A.; Kear, Felicidad T.; Santos, Anna V.P.; Ma, Jianfei; Steplock, Debra; Robey, R. Brooks; Weinman, Edward J.

    1999-01-01

    In the renal proximal tubule, the activities of the basolateral Na+/HCO3– cotransporter (NBC) and the apical Na+/H+ exchanger (NHE3) uniformly vary in parallel, suggesting that they are coordinately regulated. PKA-mediated inhibition of NHE3 is mediated by a PDZ motif–containing protein, the Na+/H+ exchanger regulatory factor (NHE-RF). Given the common inhibition of these transporters after protein kinase A (PKA) activation, we sought to determine whether NHE-RF also plays a role in PKA-regulated NBC activity. Renal cortex immunoblot analysis using anti-peptide antibodies directed against rabbit NHE-RF demonstrated the presence of this regulatory factor in both brush-border membranes (BBMs) and basolateral membranes (BLMs). Using a reconstitution assay, we found that limited trypsin digestion of detergent solubilized rabbit renal BLM preparations resulted in NBC activity that was unaffected by PKA activation. Co-reconstitution of these trypsinized preparations with a recombinant protein corresponding to wild-type rabbit NHE-RF restored the inhibitory effect of PKA on NBC activity in a concentration-dependent manner. NBC activity was inhibited 60% by 10–8M NHE-RF; this effect was not observed in the absence of PKA. Reconstitution with heat-denatured NHE-RF also failed to attenuate NBC activity. To establish further a physiologic role for NHE-RF in NBC regulation, the renal epithelial cell line B-SC-1, which lacks detectable endogenous NHE-RF expression, was engineered to express stably an NHE-RF transgene. NHE-RF–expressing B-SC-1 cells (B-SC-RF) exhibited markedly lower basal levels of NBC activity than did wild-type controls. Inhibition of NBC activity in B-SC-RF cells was enhanced after 10 μM of forskolin treatment, consistent with a postulated role for NHE-RF in mediating the inhibition of NBC activity by PKA. These findings not only suggest NHE-RF involvement in PKA-regulated NBC activity, but also provide a unique molecular mechanism whereby

  2. Defective jejunal and colonic salt absorption and alteredNa +/H+ exchanger 3 (NHE3) activity in NHE regulatory factor 1 (NHERF1) adaptor protein-deficient mice

    NARCIS (Netherlands)

    N. Broere (Nellie); M. Chen (Min); A. Cinar (Ayhan); A.K. Singh (Arbind); J. Hillesheim (Jutta); B. Riederer (Beat Michel); M. Lunnemann; I. Rottinghaus (Ingrid); A. Krabbenhöft (Anja); R. Engelhardt (Regina); B. Rausch; E.J. Weinman (Edward); M. Donowitz (Mark); A. Hubbard; O. Kocher (Olivier); H.R. de Jonge (Hugo); B.M. Hogema (Boris); U. Seidler (Ursula)

    2009-01-01

    textabstractWe investigated the role of the Na+/H+ exchanger regulatory factor 1 (NHERF1) on intestinal salt and water absorption, brush border membrane (BBM) morphology, and on the NHE3 mRNA expression, protein abundance, and transport activity in the murine intestine. NHERF1-deficient mice display

  3. A Regulatory Circuit Composed of a Transcription Factor, IscR, and a Regulatory RNA, RyhB, Controls Fe-S Cluster Delivery

    Directory of Open Access Journals (Sweden)

    Pierre Mandin

    2016-09-01

    Full Text Available Fe-S clusters are cofactors conserved through all domains of life. Once assembled by dedicated ISC and/or SUF scaffolds, Fe-S clusters are conveyed to their apo-targets via A-type carrier proteins (ATCs. Escherichia coli possesses four such ATCs. ErpA is the only ATC essential under aerobiosis. Recent studies reported a possible regulation of the erpA mRNA by the small RNA (sRNA RyhB, which controls the expression of many genes under iron starvation. Surprisingly, erpA has not been identified in recent transcriptomic analysis of the iron starvation response, thus bringing into question the actual physiological significance of the putative regulation of erpA by RyhB. Using an sRNA library, we show that among 26 sRNAs, only RyhB represses the expression of an erpA-lacZ translational fusion. We further demonstrate that this repression occurs during iron starvation. Using mutational analysis, we show that RyhB base pairs to the erpA mRNA, inducing its disappearance. In addition, IscR, the master regulator of Fe-S homeostasis, represses expression of erpA at the transcriptional level when iron is abundant, but depleting iron from the medium alleviates this repression. The conjunction of transcriptional derepression by IscR and posttranscriptional repression by RyhB under Fe-limiting conditions is best described as an incoherent regulatory circuit. This double regulation allows full expression of erpA at iron concentrations for which Fe-S biogenesis switches from the ISC to the SUF system. We further provide evidence that this regulatory circuit coordinates ATC usage to iron availability.

  4. Regulatory agencies and regulatory risk

    OpenAIRE

    Knieps, Günter; Weiß, Hans-Jörg

    2007-01-01

    The aim of this paper is to show that regulatory risk is due to the discretionary behaviour of regulatory agencies, caused by a too extensive regulatory mandate provided by the legislator. The normative point of reference and a behavioural model of regulatory agencies based on the positive theory of regulation are presented. Regulatory risk with regard to the future behaviour of regulatory agencies is modelled as the consequence of the ex ante uncertainty about the relative influence of inter...

  5. Auxin Response Factor SlARF2 Is an Essential Component of the Regulatory Mechanism Controlling Fruit Ripening in Tomato.

    Science.gov (United States)

    Hao, Yanwei; Hu, Guojian; Breitel, Dario; Liu, Mingchun; Mila, Isabelle; Frasse, Pierre; Fu, Yongyao; Aharoni, Asaph; Bouzayen, Mondher; Zouine, Mohamed

    2015-12-01

    Ethylene is the main regulator of climacteric fruit ripening, by contrast the putative role of other phytohormones in this process remains poorly understood. The present study brings auxin signaling components into the mechanism regulating tomato fruit ripening through the functional characterization of Auxin Response Factor2 (SlARF2) which encodes a downstream component of auxin signaling. Two paralogs, SlARF2A and SlARF2B, are found in the tomato genome, both displaying a marked ripening-associated expression but distinct responsiveness to ethylene and auxin. Down-regulation of either SlARF2A or SlARF2B resulted in ripening defects while simultaneous silencing of both genes led to severe ripening inhibition suggesting a functional redundancy among the two ARFs. Tomato fruits under-expressing SlARF2 produced less climacteric ethylene and exhibited a dramatic down-regulation of the key ripening regulators RIN, CNR, NOR and TAGL1. Ethylene treatment failed to reverse the non-ripening phenotype and the expression of ethylene signaling and biosynthesis genes was strongly altered in SlARF2 down-regulated fruits. Although both SlARF proteins are transcriptional repressors the data indicate they work as positive regulators of tomato fruit ripening. Altogether, the study defines SlARF2 as a new component of the regulatory network controlling the ripening process in tomato.

  6. Auxin Response Factor SlARF2 Is an Essential Component of the Regulatory Mechanism Controlling Fruit Ripening in Tomato.

    Directory of Open Access Journals (Sweden)

    Yanwei Hao

    2015-12-01

    Full Text Available Ethylene is the main regulator of climacteric fruit ripening, by contrast the putative role of other phytohormones in this process remains poorly understood. The present study brings auxin signaling components into the mechanism regulating tomato fruit ripening through the functional characterization of Auxin Response Factor2 (SlARF2 which encodes a downstream component of auxin signaling. Two paralogs, SlARF2A and SlARF2B, are found in the tomato genome, both displaying a marked ripening-associated expression but distinct responsiveness to ethylene and auxin. Down-regulation of either SlARF2A or SlARF2B resulted in ripening defects while simultaneous silencing of both genes led to severe ripening inhibition suggesting a functional redundancy among the two ARFs. Tomato fruits under-expressing SlARF2 produced less climacteric ethylene and exhibited a dramatic down-regulation of the key ripening regulators RIN, CNR, NOR and TAGL1. Ethylene treatment failed to reverse the non-ripening phenotype and the expression of ethylene signaling and biosynthesis genes was strongly altered in SlARF2 down-regulated fruits. Although both SlARF proteins are transcriptional repressors the data indicate they work as positive regulators of tomato fruit ripening. Altogether, the study defines SlARF2 as a new component of the regulatory network controlling the ripening process in tomato.

  7. The PDZ Protein Na+/H+ Exchanger Regulatory Factor-1 (NHERF1) Regulates Planar Cell Polarity and Motile Cilia Organization.

    Science.gov (United States)

    Treat, Anny Caceres; Wheeler, David S; Stolz, Donna B; Tsang, Michael; Friedman, Peter A; Romero, Guillermo

    2016-01-01

    Directional flow of the cerebrospinal fluid requires coordinated movement of the motile cilia of the ependymal epithelium that lines the cerebral ventricles. Here we report that mice lacking the Na+/H+ Exchanger Regulatory Factor 1 (NHERF1/Slc9a3r1, also known as EBP50) develop profound communicating hydrocephalus associated with fewer and disorganized ependymal cilia. Knockdown of NHERF1/slc9a3r1 in zebrafish embryos also causes severe hydrocephalus of the hindbrain and impaired ciliogenesis in the otic vesicle. Ultrastructural analysis did not reveal defects in the shape or organization of individual cilia. Similar phenotypes have been described in animals with deficiencies in Wnt signaling and the Planar Cell Polarity (PCP) pathway. We show that NHERF1 binds the PCP core genes Frizzled (Fzd) and Vangl. We further show that NHERF1 assembles a ternary complex with Fzd4 and Vangl2 and promotes translocation of Vangl2 to the plasma membrane, in particular to the apical surface of ependymal cells. Taken together, these results strongly support an important role for NHERF1 in the regulation of PCP signaling and the development of functional motile cilia.

  8. Dynamic Na+-H+ Exchanger Regulatory Factor-1 Association and Dissociation Regulate Parathyroid Hormone Receptor Trafficking at Membrane Microdomains*

    Science.gov (United States)

    Ardura, Juan A.; Wang, Bin; Watkins, Simon C.; Vilardaga, Jean-Pierre; Friedman, Peter A.

    2011-01-01

    Na/H exchanger regulatory factor-1 (NHERF1) is a cytoplasmic PDZ (postsynaptic density 95/disc large/zona occludens) protein that assembles macromolecular complexes and determines the localization, trafficking, and signaling of select G protein-coupled receptors and other membrane-delimited proteins. The parathyroid hormone receptor (PTHR), which regulates mineral ion homeostasis and bone turnover, is a G protein-coupled receptor harboring a PDZ-binding motif that enables association with NHERF1 and tethering to the actin cytoskeleton. NHERF1 interactions with the PTHR modify its trafficking and signaling. Here, we characterized by live cell imaging the mechanism whereby NHERF1 coordinates the interactions of multiple proteins, as well as the fate of NHERF1 itself upon receptor activation. Upon PTHR stimulation, NHERF1 rapidly dissociates from the receptor and induces receptor aggregation in long lasting clusters that are enriched with the actin-binding protein ezrin and with clathrin. After NHERF1 dissociates from the PTHR, ezrin then directly interacts with the PTHR to stabilize the PTHR at the cell membrane. Recruitment of β-arrestins to the PTHR is delayed until NHERF1 dissociates from the receptor, which is then trafficked to clathrin for internalization. The ability of NHERF to interact dynamically with the PTHR and cognate adapter proteins regulates receptor trafficking and signaling in a spatially and temporally coordinated manner. PMID:21832055

  9. Dynamic Na+-H+ exchanger regulatory factor-1 association and dissociation regulate parathyroid hormone receptor trafficking at membrane microdomains.

    Science.gov (United States)

    Ardura, Juan A; Wang, Bin; Watkins, Simon C; Vilardaga, Jean-Pierre; Friedman, Peter A

    2011-10-07

    Na/H exchanger regulatory factor-1 (NHERF1) is a cytoplasmic PDZ (postsynaptic density 95/disc large/zona occludens) protein that assembles macromolecular complexes and determines the localization, trafficking, and signaling of select G protein-coupled receptors and other membrane-delimited proteins. The parathyroid hormone receptor (PTHR), which regulates mineral ion homeostasis and bone turnover, is a G protein-coupled receptor harboring a PDZ-binding motif that enables association with NHERF1 and tethering to the actin cytoskeleton. NHERF1 interactions with the PTHR modify its trafficking and signaling. Here, we characterized by live cell imaging the mechanism whereby NHERF1 coordinates the interactions of multiple proteins, as well as the fate of NHERF1 itself upon receptor activation. Upon PTHR stimulation, NHERF1 rapidly dissociates from the receptor and induces receptor aggregation in long lasting clusters that are enriched with the actin-binding protein ezrin and with clathrin. After NHERF1 dissociates from the PTHR, ezrin then directly interacts with the PTHR to stabilize the PTHR at the cell membrane. Recruitment of β-arrestins to the PTHR is delayed until NHERF1 dissociates from the receptor, which is then trafficked to clathrin for internalization. The ability of NHERF to interact dynamically with the PTHR and cognate adapter proteins regulates receptor trafficking and signaling in a spatially and temporally coordinated manner.

  10. Na/H Exchanger Regulatory Factors Control Parathyroid Hormone Receptor Signaling by Facilitating Differential Activation of Gα Protein Subunits*

    Science.gov (United States)

    Wang, Bin; Ardura, Juan A.; Romero, Guillermo; Yang, Yanmei; Hall, Randy A.; Friedman, Peter A.

    2010-01-01

    The Na/H exchanger regulatory factors, NHERF1 and NHERF2, are adapter proteins involved in targeting and assembly of protein complexes. The parathyroid hormone receptor (PTHR) interacts with both NHERF1 and NHERF2. The NHERF proteins toggle PTHR signaling from predominantly activation of adenylyl cyclase in the absence of NHERF to principally stimulation of phospholipase C when the NHERF proteins are expressed. We hypothesized that this signaling switch occurs at the level of the G protein. We measured G protein activation by [35S]GTPγS binding and Gα subtype-specific immunoprecipitation using three different cellular models of PTHR signaling. These studies revealed that PTHR interactions with NHERF1 enhance receptor-mediated stimulation of Gαq but have no effect on stimulation of Gαi or Gαs. In contrast, PTHR associations with NHERF2 enhance receptor-mediated stimulation of both Gαq and Gαi but decrease stimulation of Gαs. Consistent with these functional data, NHERF2 formed cellular complexes with both Gαq and Gαi, whereas NHERF1 was found to interact only with Gαq. These findings demonstrate that NHERF interactions regulate PTHR signaling at the level of G proteins and that NHERF1 and NHERF2 exhibit isotype-specific effects on G protein activation. PMID:20562104

  11. Genetic variation in metallothionein and metal-regulatory transcription factor 1 in relation to urinary cadmium, copper, and zinc

    Science.gov (United States)

    Adams, Scott V.; Barrick, Brian; Freney, Emily P.; Shafer, Martin M.; Makar, Karen; Song, Xiaoling; Lampe, Johanna; Vilchis, Hugo; Ulery, April; Newcomb, Polly A.

    2015-01-01

    Background Metallothionein (MT) proteins play critical roles in the physiological handling of both essential (Cu and Zn) and toxic (Cd) metals. MT expression is regulated by metal-regulatory transcription factor 1 (MTF1). Hence, genetic variation in the MT gene family and MTF1 might therefore influence excretion of these metals. Methods 321 women were recruited in Seattle, WA and Las Cruces, NM and provided demographic information, urine samples for measurement of metal concentrations by mass spectrometry and creatinine, and blood or saliva for extraction of DNA. Forty-one single nucleotide polymorphisms (SNPs) within the MTF1 gene region and the region of chromosome 16 encoding the MT gene family were selected for genotyping in addition to an ancestry informative marker panel. Linear regression was used to estimate the association of SNPs with urinary Cd, Cu, and Zn, adjusted for age, urinary creatinine, smoking history, study site, and ancestry. Results Minor alleles of rs28366003 and rs10636 near the MT2A gene were associated with lower urinary Cd, Cu, and Zn. Minor alleles of rs8044719 and rs1599823, near MT1A and MT1B, were associated with lower urinary Cd and Zn, respectively. Minor alleles of rs4653329 in MTF1 was associated with lower urinary Cd. Conclusions These results suggest that genetic variation in the MT gene region and MTF1 influences urinary Cd, Cu, and Zn excretion. PMID:26529669

  12. Does positive selection drive transcription factor binding site turnover? A test with Drosophila cis-regulatory modules.

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    Bin Z He

    2011-04-01

    Full Text Available Transcription factor binding site(s (TFBS gain and loss (i.e., turnover is a well-documented feature of cis-regulatory module (CRM evolution, yet little attention has been paid to the evolutionary force(s driving this turnover process. The predominant view, motivated by its widespread occurrence, emphasizes the importance of compensatory mutation and genetic drift. Positive selection, in contrast, although it has been invoked in specific instances of adaptive gene expression evolution, has not been considered as a general alternative to neutral compensatory evolution. In this study we evaluate the two hypotheses by analyzing patterns of single nucleotide polymorphism in the TFBS of well-characterized CRM in two closely related Drosophila species, Drosophila melanogaster and Drosophila simulans. An important feature of the analysis is classification of TFBS mutations according to the direction of their predicted effect on binding affinity, which allows gains and losses to be evaluated independently along the two phylogenetic lineages. The observed patterns of polymorphism and divergence are not compatible with neutral evolution for either class of mutations. Instead, multiple lines of evidence are consistent with contributions of positive selection to TFBS gain and loss as well as purifying selection in its maintenance. In discussion, we propose a model to reconcile the finding of selection driving TFBS turnover with constrained CRM function over long evolutionary time.

  13. Reconstruction and analysis of transcription factor-miRNA co-regulatory feed-forward loops in human cancers using filter-wrapper feature selection.

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    Chen Peng

    Full Text Available BACKGROUND: As one of the most common types of co-regulatory motifs, feed-forward loops (FFLs control many cell functions and play an important role in human cancers. Therefore, it is crucial to reconstruct and analyze cancer-related FFLs that are controlled by transcription factor (TF and microRNA (miRNA simultaneously, in order to find out how miRNAs and TFs cooperate with each other in cancer cells and how they contribute to carcinogenesis. Current FFL studies rely on predicted regulation information and therefore suffer the false positive issue in prediction results. More critically, FFLs generated by existing approaches cannot represent the dynamic and conditional regulation relationship under different experimental conditions. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we proposed a novel filter-wrapper feature selection method to accurately identify co-regulatory mechanism by incorporating prior information from predicted regulatory interactions with parallel miRNA/mRNA expression datasets. By applying this method, we reconstructed 208 and 110 TF-miRNA co-regulatory FFLs from human pan-cancer and prostate datasets, respectively. Further analysis of these cancer-related FFLs showed that the top-ranking TF STAT3 and miRNA hsa-let-7e are key regulators implicated in human cancers, which have regulated targets significantly enriched in cellular process regulations and signaling pathways that are involved in carcinogenesis. CONCLUSIONS/SIGNIFICANCE: In this study, we introduced an efficient computational approach to reconstruct co-regulatory FFLs by accurately identifying gene co-regulatory interactions. The strength of the proposed feature selection method lies in the fact it can precisely filter out false positives in predicted regulatory interactions by quantitatively modeling the complex co-regulation of target genes mediated by TFs and miRNAs simultaneously. Moreover, the proposed feature selection method can be generally applied to

  14. Vpu mediates depletion of interferon regulatory factor 3 during HIV infection by a lysosome-dependent mechanism.

    Science.gov (United States)

    Doehle, Brian P; Chang, Kristina; Rustagi, Arjun; McNevin, John; McElrath, M Juliana; Gale, Michael

    2012-08-01

    HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV.

  15. Dynamic changes in binding of immunoglobulin heavy chain 3' regulatory region to protein factors during class switching.

    Science.gov (United States)

    Chatterjee, Sanjukta; Ju, Zhongliang; Hassan, Rabih; Volpi, Sabrina A; Emelyanov, Alexander V; Birshtein, Barbara K

    2011-08-19

    The 3' regulatory region (3' RR) of the Igh locus works at long distances on variable region (V(H)) and switch region (I) region promoters to initiate germ line (non-coding) transcription (GT) and promote class switch recombination (CSR). The 3' RR contains multiple elements, including enhancers (hs3a, hs1.2, hs3b, and hs4) and a proposed insulator region containing CTCF (CCCTC-binding factor) binding sites, i.e. hs5/6/7 and the downstream region ("38"). Notably, deletion of each individual enhancer (hs3a-hs4) has no significant phenotypic consequence, suggesting that the 3' RR has considerable structural flexibility in its function. To better understand how the 3' RR functions, we identified transcription factor binding sites and used chromatin immunoprecipitation (ChIP) assays to monitor their occupancy in splenic B cells that initiate GT and undergo CSR (LPS±IL4), are deficient in GT and CSR (p50(-/-)), or do not undergo CSR despite efficient GT (anti-IgM+IL4). Like 3' RR enhancers, hs5-7 and the 38 region were observed to contain multiple Pax5 binding sites (in addition to multiple CTCF sites). We found that the Pax5 binding profile to the 3' RR dynamically changed during CSR independent of the specific isotype to which switching was induced, and binding focused on hs1.2, hs4, and hs7. CTCF-associated and CTCF-independent cohesin interactions were also identified. Our observations are consistent with a scaffold model in which a platform of active protein complexes capable of facilitating GT and CSR can be formed by varying constellations of 3' RR elements.

  16. Interferon regulatory factor-1 mediates the release of high mobility group box-1 in endotoxemia in mice

    Institute of Scientific and Technical Information of China (English)

    PAN Pin-hua; Jon Cardinal; LI Mo-li; HU Cheng-ping; Allan Tsung

    2013-01-01

    Background The extracellular release of the danger signal high mobility group box-1 (HMGB1) has been implicated in the pathogenesis and outcomes of sepsis.Understanding the mechanisms responsible for HMGB1 release can lead to the identification of targets that may inhibit this process.The transcription factor interferon regulatory factor-1 (IRF-1) is an important mediator of innate immune responses and has been shown to participate in mortality associated with endotoxemia; however,its role in mediating the release of HMGB1 in these settings is unknown.Methods Male IRF-1 knockout (KO) and age matched C57BL/6 wild type (WT) mice were given intraperitoneal (IP)injections of lipopolysaccharide (LPS).In some experiments,96 hours survival rates were observed.In other experiments,mice were sacrificed 12 hours after LPS administration and sera were harvested for future analysis.In in vitro study,RAW 264.7 murine monocyte/macrophage-like cells or primary peritoneal macrophage obtained from IRF-1 KO and WF mice were cultured for LPS mediated HMGB1 release analysis.And the mechanism for HMGB1 release was analyzed by immune-precipitation.Results IRF-1 KO mice experienced less mortality,and released less systerric HMGB1 compared to their WT counterparts.Exogenous administration of recombinant HMGB1 to IRF-1 KO mice returned the mortality rate to that seen originally in IRF-1 WT mice.Using cultures of peritoneal macrophages or RAW264.7 cells,in vitro LPS stimulation induced the release of HMGB1 in an IRF-1 dependent manner.And the janus associated kinase (JAK)-IRF-1 signal pathway appeared to participate in the signaling mechanisms of LPS-induced HMGB1 release by mediating acetylation of HMGB1.Conclusion IRF-1 plays a role in LPS induced release of HMGB1 and therefore may serve as a novel target in sepsis.

  17. Interferon regulatory factor 8-deficiency determines massive neutrophil recruitment but T cell defect in fast growing granulomas during tuberculosis.

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    Stefano Rocca

    Full Text Available Following Mycobacterium tuberculosis (Mtb infection, immune cell recruitment in lungs is pivotal in establishing protective immunity through granuloma formation and neogenesis of lymphoid structures (LS. Interferon regulatory factor-8 (IRF-8 plays an important role in host defense against Mtb, although the mechanisms driving anti-mycobacterial immunity remain unclear. In this study, IRF-8 deficient mice (IRF-8⁻/⁻ were aerogenously infected with a low-dose Mtb Erdman virulent strain and the course of infection was compared with that induced in wild-type (WT-B6 counterparts. Tuberculosis (TB progression was examined in both groups using pathological, microbiological and immunological parameters. Following Mtb exposure, the bacterial load in lungs and spleens progressed comparably in the two groups for two weeks, after which IRF-8⁻/⁻ mice developed a fatal acute TB whereas in WT-B6 the disease reached a chronic stage. In lungs of IRF-8⁻/⁻, uncontrolled growth of pulmonary granulomas and impaired development of LS were observed, associated with unbalanced homeostatic chemokines, progressive loss of infiltrating T lymphocytes and massive prevalence of neutrophils at late infection stages. Our data define IRF-8 as an essential factor for the maintenance of proper immune cell recruitment in granulomas and LS required to restrain Mtb infection. Moreover, IRF-8⁻/⁻ mice, relying on a common human and mouse genetic mutation linked to susceptibility/severity of mycobacterial diseases, represent a valuable model of acute TB for comparative studies with chronically-infected congenic WT-B6 for dissecting protective and pathological immune reactions.

  18. Interferon regulatory factor 8-deficiency determines massive neutrophil recruitment but T cell defect in fast growing granulomas during tuberculosis.

    Science.gov (United States)

    Rocca, Stefano; Schiavoni, Giovanna; Sali, Michela; Anfossi, Antonio Giovanni; Abalsamo, Laura; Palucci, Ivana; Mattei, Fabrizio; Sanchez, Massimo; Giagu, Anna; Antuofermo, Elisabetta; Fadda, Giovanni; Belardelli, Filippo; Delogu, Giovanni; Gabriele, Lucia

    2013-01-01

    Following Mycobacterium tuberculosis (Mtb) infection, immune cell recruitment in lungs is pivotal in establishing protective immunity through granuloma formation and neogenesis of lymphoid structures (LS). Interferon regulatory factor-8 (IRF-8) plays an important role in host defense against Mtb, although the mechanisms driving anti-mycobacterial immunity remain unclear. In this study, IRF-8 deficient mice (IRF-8⁻/⁻) were aerogenously infected with a low-dose Mtb Erdman virulent strain and the course of infection was compared with that induced in wild-type (WT-B6) counterparts. Tuberculosis (TB) progression was examined in both groups using pathological, microbiological and immunological parameters. Following Mtb exposure, the bacterial load in lungs and spleens progressed comparably in the two groups for two weeks, after which IRF-8⁻/⁻ mice developed a fatal acute TB whereas in WT-B6 the disease reached a chronic stage. In lungs of IRF-8⁻/⁻, uncontrolled growth of pulmonary granulomas and impaired development of LS were observed, associated with unbalanced homeostatic chemokines, progressive loss of infiltrating T lymphocytes and massive prevalence of neutrophils at late infection stages. Our data define IRF-8 as an essential factor for the maintenance of proper immune cell recruitment in granulomas and LS required to restrain Mtb infection. Moreover, IRF-8⁻/⁻ mice, relying on a common human and mouse genetic mutation linked to susceptibility/severity of mycobacterial diseases, represent a valuable model of acute TB for comparative studies with chronically-infected congenic WT-B6 for dissecting protective and pathological immune reactions.

  19. Regulatory mechanism of pyrrolidine dithiocarbamate is mediated by nuclear factor-κB and inhibits neutrophil accumulation in ARDS mice.

    Science.gov (United States)

    Wang, Hongman; Xu, Lisheng; Zhao, Jiping; Wang, Donghui; Guo, Ranran; Wang, Junfei; Gong, Wenbin; Liu, Tian; Zhang, Yuanyuan; Dong, Liang

    2014-08-01

    The aim of the present study was to investigate the regulatory mechanism of nuclear factor (NF)-κB on polymorphonuclear neutrophil (PMN) accumulation and the inflammatory response in lung tissues with acute respiratory distress syndrome (ARDS), as well as the therapeutic effect of pyrrolidine dithiocarbamate (PDTC). Mouse models of ARDS were established by intraperitoneal injection of lipopolysaccharide (LPS). BALB/c mice were divided into control, LPS and PDTC + LPS groups. The expression of PMN adhesion molecules, CD11b/CD18 and intercellular adhesion molecule-1 (ICAM-1), were detected by immunohistochemistry, while the protein expression levels of NF-κB p65 in the lung tissue were analyzed by western blot analysis. In addition, flow cytometry was used to investigate the apoptosis rate of PMNs in the bronchoalveolar fluid, and the expression levels of interleukin (IL)-1β, IL-8 and tumor necrosis factor (TNF)-α and myeloperoxidase (MPO) activity were also determined. Following an intraperitoneal injection of LPS, alveolar septum rupture, pulmonary interstitial hyperemia and PMN infiltration in the alveolar was observed. The protein expression of p65 in the pulmonary cytoplasm decreased, while the expression of p65 in the nucleus increased. The levels of IL-8, IL-1β and TNF-α increased and the high expression status was maintained for 24 h. As the time increased, CD11b/CD18 and ICAM-1 expression increased, as well as MPO activity, while the apoptosis of PMNs was delayed. Compared with the LPS group, the expression of p65 in the pulmonary cytoplasm and the PMN apoptosis rate increased following PDTC intervention, while the expression of p65 in the nucleus decreased, as well as the expression levels of the cytokines and MPO activity. Therefore, PDTC reduced the production of inflammatory cytokines via the NF-κB pathway, which reduced the activation of PMNs in the lung tissue and promoted PMN apoptosis.

  20. The carboxy-terminal domain of Dictyostelium C-module-binding factor is an independent gene regulatory entity.

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    Jörg Lucas

    Full Text Available The C-module-binding factor (CbfA is a multidomain protein that belongs to the family of jumonji-type (JmjC transcription regulators. In the social amoeba Dictyostelium discoideum, CbfA regulates gene expression during the unicellular growth phase and multicellular development. CbfA and a related D. discoideum CbfA-like protein, CbfB, share a paralogous domain arrangement that includes the JmjC domain, presumably a chromatin-remodeling activity, and two zinc finger-like (ZF motifs. On the other hand, the CbfA and CbfB proteins have completely different carboxy-terminal domains, suggesting that the plasticity of such domains may have contributed to the adaptation of the CbfA-like transcription factors to the rapid genome evolution in the dictyostelid clade. To support this hypothesis we performed DNA microarray and real-time RT-PCR measurements and found that CbfA regulates at least 160 genes during the vegetative growth of D. discoideum cells. Functional annotation of these genes revealed that CbfA predominantly controls the expression of gene products involved in housekeeping functions, such as carbohydrate, purine nucleoside/nucleotide, and amino acid metabolism. The CbfA protein displays two different mechanisms of gene regulation. The expression of one set of CbfA-dependent genes requires at least the JmjC/ZF domain of the CbfA protein and thus may depend on chromatin modulation. Regulation of the larger group of genes, however, does not depend on the entire CbfA protein and requires only the carboxy-terminal domain of CbfA (CbfA-CTD. An AT-hook motif located in CbfA-CTD, which is known to mediate DNA binding to A+T-rich sequences in vitro, contributed to CbfA-CTD-dependent gene regulatory functions in vivo.

  1. Transforming growth factor-beta1 inhibits tissue engineering cartilage absorption via inducing the generation of regulatory T cells.

    Science.gov (United States)

    Li, Chichi; Bi, Wei; Gong, Yiming; Ding, Xiaojun; Guo, Xuehua; Sun, Jian; Cui, Lei; Yu, Youcheng

    2016-02-01

    The objective of the present study was to explore the mechanisms of transforming growth factor (TGF)-β1 inhibiting the absorption of tissue engineering cartilage. We transfected TGF-β1 gene into bone marrow mesenchymal stem cells (BMMSCs) and co-cultured with interferon (IFN)-γ and tumour necrosis factor (TNF)-α and CD4(+) CD25(-) T lymphocytes. We then characterized the morphological changes, apoptosis and characterization of chondrogenic-committed cells from TGF-β1(+) BMMSCs and explored their mechanisms. Results showed that BMMSCs apoptosis and tissue engineering cartilage absorption in the group with added IFN-γ and TNF-α were greater than in the control group. In contrast, there was little BMMSC apoptosis and absorption by tissue engineering cartilage in the group with added CD4(+) CD25(-) T lymphocytes; Foxp3(+) T cells and CD25(+) CD39(+) T cells were found. In contrast, no type II collagen or Foxp3(+) T cells or CD25(+) CD39(+) T cells was found in the TGF-β1(-) BMMSC group. The data suggest that IFN-γ and TNF-α induced BMMSCs apoptosis and absorption of tissue engineering cartilage, but the newborn regulatory T (Treg) cells inhibited the function of IFN-γ and TNF-α and protected BMMSCs and tissue engineering cartilage. TGF-β1not only played a cartilage inductive role, but also inhibited the absorption of tissue engineering cartilage. The pathway proposed in our study may simulate the actual reaction procedure after implantation of BMMSCs and tissue engineering cartilage in vivo. Copyright © 2013 John Wiley & Sons, Ltd.

  2. Vpu Mediates Depletion of Interferon Regulatory Factor 3 during HIV Infection by a Lysosome-Dependent Mechanism

    Science.gov (United States)

    Doehle, Brian P.; Chang, Kristina; Rustagi, Arjun; McNevin, John; McElrath, M. Juliana

    2012-01-01

    HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV. PMID:22593165

  3. The expression of tumor necrosis factor-alpha, its receptors and steroidogenic acute regulatory protein during corpus luteum regression

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    Arfuso Frank

    2008-11-01

    Full Text Available Abstract Background Corpus luteum (CL regression is known to occur as two parts; functional regression when steroidogenesis declines and structural regression when apoptosis is induced. Previous studies suggest this process occurs by the production of luteolytic factors, such as tumour necrosis factor-alpha (TNF-alpha. Methods We examined TNF-alpha, TNF-alpha receptors (TNFR1 and 2 and steroidogenic acute regulatory (StAR protein expression during CL regression in albino Wistar rats. CL from Days 16 and 22 of pregnancy and Day 3 post-partum were examined, in addition CL from Day 16 of pregnancy were cultured in vitro to induce apoptosis. mRNA was quantitated by kinetic RT-PCR and protein expression examined by immunohistochemistry and Western blot analyses. Results TNF-alpha mRNA increased on Day 3 post-partum. TNFR were immunolocalized to luteal cells, and an increase in TNFR2 mRNA observed on Day 3 post-partum whilst no change was detected in TNFR1 mRNA relative to Day 16. StAR protein decreased on Day 3 post-partum and following trophic withdrawal but no change was observed following exogenous TNF-alpha treatment. StAR mRNA decreased on Day 3 post-partum; however, it increased following trophic withdrawal and TNF-alpha treatment in vitro. Conclusion These results demonstrate the existence of TNFR1 and TNFR2 in rat CL and suggest the involvement of TNF-alpha in rat CL regression following parturition. Furthermore, decreased StAR expression over the same time points was consistent with the functional regression of the CL.

  4. Expression of Smad7 and Smad ubiquitin regulatory factor 2 in a rat model of chronic pancreatitis.

    Science.gov (United States)

    Hou, Xiao Jia; Jin, Zhen Dong; Jiang, Fei; Zhu, Jian Wei; Li, Zhao Shen

    2015-07-01

    To quantify the expressions of Smad7 and Smad ubiquitin regulatory factor 2 (Smurf2) in the pancreas in rats with chronic pancreatitis (CP). A total of 16 male Wistar rats were randomly divided into the control group and the CP group, with 8 rats in each group. CP was induced in vivo with dibutyltin dichloride (DBTC). Four weeks after DBTC administration, histological assessment and the measurement of hydroxyproline content in the pancreatic tissues were performed to assess the inflammation and fibrosis of the pancreas. Immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) for transforming growth factor (TGF)-β1 and α-smooth muscle actin (α-SMA) were applied to assess activated pancreatic stellate cells (PSC) and TGF-β1 expression. Smad7 and Smurf2 expressions in the pancreas were measured using Western blot and RT-PCR. Typical histopathological characteristics of DBTC-induced CP in the rats with extensively activated PSC. Compared with the control group, the expressions of TGF-β1, α-SMA and hydroxyproline content in the pancreatic tissues in the CP group were significantly increased. Meanwhile, the mRNA and protein expressions of Smad7 and Smurf2 were significant increased in the fibrotic pancreas, in which the expressions of Smad7 proteins showed an obvious reduction compared with controls. The dysregulation of Smad7 and Smurf2 may be associated with the pathogenesis of pancreatic fibrosis through the TGF-β signaling pathway. © 2015 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

  5. Comparative analysis of sterol acquisition in the oomycetes Saprolegnia parasitica and Phytophthora infestans

    Science.gov (United States)

    Dahlin, Paul; Srivastava, Vaibhav; Ekengren, Sophia; McKee, Lauren S.; Bulone, Vincent

    2017-01-01

    The oomycete class includes pathogens of animals and plants which are responsible for some of the most significant global losses in agriculture and aquaculture. There is a need to replace traditional chemical means of controlling oomycete growth with more targeted approaches, and the inhibition of sterol synthesis is one promising area. To better direct these efforts, we have studied sterol acquisition in two model organisms: the sterol-autotrophic Saprolegnia parasitica, and the sterol-heterotrophic Phytophthora infestans. We first present a comprehensive reconstruction of a likely sterol synthesis pathway for S. parasitica, causative agent of the disease saprolegniasis in fish. This pathway shows multiple potential routes of sterol synthesis, and draws on several avenues of new evidence: bioinformatic mining for genes with sterol-related functions, expression analysis of these genes, and analysis of the sterol profiles in mycelium grown in different media. Additionally, we explore the extent to which P. infestans, which causes the late blight in potato, can modify exogenously provided sterols. We consider whether the two very different approaches to sterol acquisition taken by these pathogens represent any specific survival advantages or potential drug targets. PMID:28152045

  6. Sterol biosynthesis is required for heat resistance but not extracellular survival in leishmania.

    Science.gov (United States)

    Xu, Wei; Hsu, Fong-Fu; Baykal, Eda; Huang, Juyang; Zhang, Kai

    2014-10-01

    Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols) in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM) in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm(-)) were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm(-) mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm(-) causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance.

  7. Distribution of sterols and the sources of pollution in surface sediments of Ulungur lake, Xinjiang.

    Science.gov (United States)

    Yao, Xiaorui; Lu, Jianjiang; Liu, Zilong; Ran, Dan; Huang, Yating

    2013-01-01

    Domestic sewage discharged into lakes brings great pressure to the ecological environment. This study selected sediment from an inland lake as a research object to evaluate pollution of the environment. Eight sterols were used to evaluate the content of pollutants, while the ratios of sterols were used as the index to analyze the sources of pollution. The correlations were analyzed between sterols and total organic carbon (TOC), salinity and particle size. The distribution and composition of sterol compounds were determined in 12 surface sediment samples collected from Ulungur lake. The total concentrations of detected sterols in the sediments ranged from 1.3 to 36.3 μg/g.dw. The most abundant sterol detected was β-sitosterol (STI) with average concentrations of 2.6 μg/g.dw, followed by cholesterol (CHOE), stigmasterol (STIG) and stigmastanol (STAN). The concentration of coprostanol (COP) was between 0.03 and 1.66 μg/g.dw. Through correlation analysis, it was found that there was a significant correlation between fecal sterols and plant sterols. So the plant sterols shall not be neglected in evaluating the sources of pollution for their impact to identify the fecal sources. The study suggests that the composition and distribution of sterols in surface sediment provide useful information for environmental contamination monitoring and assessment in the inland lake.

  8. Sterol Biosynthesis Is Required for Heat Resistance but Not Extracellular Survival in Leishmania

    Science.gov (United States)

    Xu, Wei; Hsu, Fong-Fu; Baykal, Eda; Huang, Juyang; Zhang, Kai

    2014-01-01

    Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols) in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM) in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm −) were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm − mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm − causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance. PMID:25340392

  9. Sterol biosynthesis is required for heat resistance but not extracellular survival in leishmania.

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2014-10-01

    Full Text Available Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm(- were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm(- mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm(- causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance.

  10. Differential effects of fenpropimorph and fenhexamid, two sterol biosynthesis inhibitor fungicides, on arbuscular mycorrhizal development and sterol metabolism in carrot roots.

    Science.gov (United States)

    Campagnac, Estelle; Fontaine, Joël; Sahraoui, Anissa Lounès-Hadj; Laruelle, Frédéric; Durand, Roger; Grandmougin-Ferjani, Anne

    2008-12-01

    Sterols composition of transformed carrot roots incubated in presence of increasing concentrations of fenpropimorph (0.02; 0.2; 2mgl(-1)) and fenhexamid (0.02; 0.2; 2; 20mgl(-1)), colonized or not by Glomus intraradices was determined. In mycorrhizal roots treated with fenpropimorph, normal Delta(5)-sterols were replaced by unusual compounds such as 9beta,19-cyclopropylsterols (24-methylpollinastanol), Delta(8,14)-sterols (ergosta-8,14-dienol, stigmasta-8,14-dienol), Delta(8)-sterols (Delta(8) sitosterol) and Delta(7)-sterols (ergosta-7,22-dienol). After application of fenpropimorph, a drastic reduction of the mycorrhizal root growth, root colonization and extraradical fungal development was observed. Application of fenhexamid did not modify sterol profiles and the total colonization of roots. But the arbuscule frequency of the fungal partner was significantly affected. Comparison of the effects caused by the tested fungicides indicates that the usual phytosterols may be involved in symbiosis development. Indeed, observed modifications of root sterols composition could explain the high fenpropimorph toxicity to the AM symbiosis. However, the absence of sterolic modifications in the roots treated with fenhexamid could account for its more limited impact on mycorrhization.

  11. Evaluation of T Regulatory Lymphocytes Transcription Factors in HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) Patients.

    Science.gov (United States)

    Ghezeldasht, Sanaz Ahmadi; Sadeghian, Hamed; Azarpazhooh, Mahmoud Reza; Shamsian, Seyyed Ali Akbar; Rafatpanah, Houshang; Mahmoodi, Mahmood; Rezaee, Seyyed Abdolrahim

    2017-08-01

    HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an aggressive neurological disease. The CD4(+)CD25(+) T cell population plays pivotal roles in the maintenance of immunological tolerance and prevention of such autoimmune diseases. In the current study, proviral load (PVL), factor forkhead box p3 (Foxp3), and glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) gene expression and regulatory T cells (Tregs) counts of 21 HAM/TSP patients and 16 HTLV-1 healthy carriers (ACs) were measured using real-time PCR, TaqMan method, and flow cytometry. The demographic, history of disease, and severity of myelopathy were assessed by a checklist and the Osame motor disability score (OMDS). The mean OMDS for HAM/TSP was 4.82 ± 2.37 which had no significant correlation with Treg count or the expression of Foxp3, GITR, and PVL. The CD4(+)CD25(+) cell counts had no significant differences between HAM/TSP and ACs. Findings revealed a higher PVL in HAM/TSPs (313.36 copies/10(4)) compared to ACs (144.93 copies/10(4), p = 0.035). The Foxp3 and GITR mRNA levels were lower in HAM/TSP patients (11.78 and 13.80, respectively) than those in healthy carriers (18.44 and 21.00, p = 0.041 and 0.03, respectively). There was a significant correlation between Treg frequency and Foxp3 gene expression (R = 0.67, p = 0.006) and GITR and Foxp3 (R = 0.84, p = 0.042) in HAM/TSP patients. Furthermore, the transcription factors have strong correlations with CD4(+)CD25(+) T cell frequencies. These findings suggest that HTLV-1 infection can modify the expression of main functional transcription factors, FOXP3 and GITR, which may lead to immune response deterioration of Tregs and consequently HAM/TSP manifestation.

  12. Acute sterol o-acyltransferase 2 (SOAT2 knockdown rapidly mobilizes hepatic cholesterol for fecal excretion.

    Directory of Open Access Journals (Sweden)

    Stephanie M Marshall

    Full Text Available The primary risk factor for atherosclerotic cardiovascular disease is LDL cholesterol, which can be reduced by increasing cholesterol excretion from the body. Fecal cholesterol excretion can be driven by a hepatobiliary as well as a non-biliary pathway known as transintestinal cholesterol efflux (TICE. We previously showed that chronic knockdown of the hepatic cholesterol esterifying enzyme sterol O-acyltransferase 2 (SOAT2 increased fecal cholesterol loss via TICE. To elucidate the initial events that stimulate TICE, C57Bl/6 mice were fed a high cholesterol diet to induce hepatic cholesterol accumulation and were then treated for 1 or 2 weeks with an antisense oligonucleotide targeting SOAT2. Within 2 weeks of hepatic SOAT2 knockdown (SOAT2HKD, the concentration of cholesteryl ester in the liver was reduced by 70% without a reciprocal increase in hepatic free cholesterol. The rapid mobilization of hepatic cholesterol stores resulted in a ∼ 2-fold increase in fecal neutral sterol loss but no change in biliary cholesterol concentration. Acute SOAT2HKD increased plasma cholesterol carried primarily in lipoproteins enriched in apoB and apoE. Collectively, our data suggest that acutely reducing SOAT2 causes hepatic cholesterol to be swiftly mobilized and packaged onto nascent lipoproteins that feed cholesterol into the TICE pathway for fecal excretion.

  13. Sterols from Mytilidae show anti-aging and neuroprotective effects via anti-oxidative activity.

    Science.gov (United States)

    Sun, Yujuan; Lin, Yanfei; Cao, Xueli; Xiang, Lan; Qi, Jianhua

    2014-11-25

    For screening anti-aging samples from marine natural products, K6001 yeast strain was employed as a bioassay system. The active mussel extract was separated to give an active sterol fraction (SF). SF was further purified, and four sterol compounds were obtained. Their structures were determined to be cholesterol (CHOL), brassicasterol, crinosterol, and 24-methylenecholesterol. All compounds showed similar anti-aging activity. To understand the action mechanism involved, anti-oxidative experiments, reactive oxygen species (ROS) assays, and malondialdehyde (MDA) tests were performed on the most abundant compound, CHOL. Results indicated that treatment with CHOL increases the survival rate of yeast under oxidative stress and decreases ROS and MDA levels. In addition, mutations of uth1, skn7, sod1, and sod2, which feature a K6001 background, were employed and the lifespans of the mutations were not affected by CHOL. These results demonstrate that CHOL exerts anti-aging effects via anti-oxidative stress. Based on the connection between neuroprotection and anti-aging, neuroprotective experiments were performed in PC12 cells. Paraquat was used to induce oxidative stress and the results showed that the CHOL and SF protect the PC12 cells from the injury induced by paraquat. In addition, these substance exhibited nerve growth factor (NGF) mimic activities again confirmed their neuroprotective function.

  14. New anti-inflammatory sterols from a gorgonian Pinnigorgia sp.

    Science.gov (United States)

    Su, Yin-Di; Cheng, Ching-Hsiao; Wen, Zhi-Hong; Wu, Yang-Chang; Sung, Ping-Jyun

    2016-07-01

    Chemical investigation on the EtOAc-soluble fraction from the MeOH/DCM extract of a gorgonian Pinnigorgia sp. afforded two new sterols, 11-acetoxy-24S-methyl-3β,5α,6α-trihydroxy-9,11-secocholest-7-en-9-one (1) and 5β,6β-epoxy-(22E,24R)-ergosta-8,22-diene-3β,7β-diol (2). The structures of sterols 1 and 2 were elucidated on the basis of spectroscopic analysis and by comparison of their spectroscopic data with those of related analogues. Both 1 and 2 were shown to significantly inhibit the accumulation of the pro-inflammatory iNOS and COX-2 protein in LPS-stimulated RAW264.7 macrophage cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The sterols of Cucurbita moschata ("calabacita") seed oil.

    Science.gov (United States)

    Rodriguez, J B; Gros, E G; Bertoni, M H; Cattaneo, P

    1996-11-01

    From the sterol fraction of seed oil from commercial Cucurbita moschata Dutch ("calabacita") delta 5 and delta 7 sterols having saturated and unsaturated side chain were isolated by chromatographic procedures and characterized by spectroscopic (1H and 13C-nuclear magnetic resonance, mass spectrometry) methods. The main components were identified as 24S-ethyl 5 alpha-cholesta-7,22E-dien-3 beta-ol (alpha-spinasterol); 24S-ethyl 5 alpha-cholesta-7,22E,25-trien-3 beta-ol (25-dehydrochondrillasterol); 24S-ethyl 5 alpha-cholesta-7,25-dien-3 beta-ol; 24R-ethyl-cholesta-7-en-3 beta-ol (delta 7-stigmastenol) and 24-ethyl-cholesta-7, 24(28)-dien-3 beta-ol (delta 7,24(28)-stigmastadienol).

  16. The Identification of Two New Sterols from Marine Organism

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two new sterol have been isolated from the South China Sea marine organism. Compound 1 was isolated from the sponge Polymastia sobustia and compound 2 was obtained from the soft coral Sinularia inexplicata. Their structures were established as 3β -hydroxy- stigmast-5en-7-one and 24 - methylene cholestan -3β, 6β, 9α, 19 -tetrol by variety of spectral analysis such as IR, EIMS, 1DNMR, 1H-1H COSY, HMQC, HMBC, NOESY.

  17. [Sterol extracts from Begonia Sinensis Rhizome against respiratory inflammation].

    Science.gov (United States)

    Yao, Yong; Jiang, Wei; Li, Yu-shan

    2015-08-01

    The acute and chronic respiratory tract inflammation models were made to investigate the effect and mechanism of sterol extracts from Begonia Sinensis Rhizome (BSR). The first model of acute lung injury was made with Kunming mice by inhaling cigarette smoke, then the mice were treated with different concentrations of BSR sterol extracts. Lung tissue morphology was detected by HE staining, TNF-alpha/MPO were detected by Elisa, and cPLA2 protein were, detected by Western blotting respectively. Results showed that in model group, lung sheet became real, alveolar space shrank or disappeared, alveolar septum was thickened, plenty of inflammatory cells were infiltrated, capillary blood vessels were congestive and the expression of TNF-α, MPO, cPLA2 increased; after administration, a small amount of inflammatory cells were infiltrated, alveolar septum became obvious, capillary congestion status was significantly relieved and the expression of TNF-α, MPO, cPLA2 decreased (P < 0.05). The second model of chronic respiratory tract inflammation in BALB/c mice with bronchial asthma was induced by OVA, then the mice were treated with different concentrations of BSR sterol extracts. Lung tissue morphology was detected by HE staining, indexes such as IL-4, IL-5, IL-13 were detected by Elisa, and the cPLA2 protein expression was detected by Western blotting respectively. Results showed that in model group, a lot of inflammatory cells around lung vessels and bronchi exuded, bronchial goblet cells proliferated and the expression of IL-4, IL-5, IL-13, cPLA2 increased; after administration, inflammatory and goblet cell hyperplasia reduced, the expression of IL-4, IL-5, IL-13, cPLA2 also decreased (P < 0.05). The above results showed BSR sterol extracts could resist against respiratory inflammation by inhibiting cPLA2 in a dose-dependent manner.

  18. Building Synthetic Sterols Computationally - Unlocking the Secrets of Evolution?

    DEFF Research Database (Denmark)

    Róg, Tomasz; Pöyry, Sanja; Vattulainen, Ilpo

    2015-01-01

    Cholesterol is vital in regulating the physical properties of animal cell membranes. While it remains unclear what renders cholesterol so unique, it is known that other sterols are less capable in modulating membrane properties, and there are membrane proteins whose function is dependent on chole......Cholesterol is vital in regulating the physical properties of animal cell membranes. While it remains unclear what renders cholesterol so unique, it is known that other sterols are less capable in modulating membrane properties, and there are membrane proteins whose function is dependent...... on cholesterol. Practical applications of cholesterol include its use in liposomes in drug delivery and cosmetics, cholesterol-based detergents in membrane protein crystallography, its fluorescent analogs in studies of cholesterol transport in cells and tissues, etc. Clearly, in spite of their difficult...... dynamics simulation studies that have predicted new synthetic sterols with properties comparable to those of cholesterol. We also discuss more recent experimental studies that have vindicated these predictions. The paper highlights the strength of computational simulations in making predictions...

  19. Distribution of free and glycosylated sterols within Cycas micronesica plants

    Science.gov (United States)

    Marler, Thomas E.; Shaw, Christopher A.

    2010-01-01

    Flour derived from Cycas micronesica seeds was once the dominant source of starch for Guam's residents. Cycad consumption has been linked to high incidence of human neurodegenerative diseases. We determined the distribution of the sterols stigmasterol and β-sitosterol and their derived glucosides stigmasterol β-d-glucoside and β-sitosterol β-d-glucoside among various plant parts because they have been identified in cycad flour and have been shown to elicit neurodegenerative outcomes. All four compounds were common in seeds, sporophylls, pollen, leaves, stems, and roots. Roots contained the greatest concentration of both free sterols, and photosynthetic leaflet tissue contained the greatest concentration of both steryl glucosides. Concentration within the three stem tissue categories was low compared to other organs. Reproductive sporophyll tissue contained free sterols similar to seeds, but greater concentration of steryl glucosides than seeds. One of the glucosides was absent from pollen. Concentration in young seeds was higher than old seeds as reported earlier, but concentration did not differ among age categories of leaf, sporophyll, or vascular tissue. The profile differences among the various tissues within these organs may help clarify the physiological role of these compounds. PMID:20157629

  20. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase (SAM:SMT)

    Science.gov (United States)

    Kaneshiro, Edna S.; Johnston, Laura Q.; Nkinin, Stephenson W.; Romero, Becky I.; Giner, José-Luis

    2014-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The P. carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography (HPLC) and proton nuclear magnetic resonance spectroscopy (1H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ24(28)-sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii. PMID:25230683

  1. Secretion and Signaling Activities of Lipoprotein-Associated Hedgehog and Non-Sterol-Modified Hedgehog in Flies and Mammals

    Science.gov (United States)

    Kumari, Veena; Ehrhart-Bornstein, Monika; Bornstein, Stefan R.; Eaton, Suzanne

    2013-01-01

    Hedgehog (Hh) proteins control animal development and tissue homeostasis. They activate gene expression by regulating processing, stability, and activation of Gli/Cubitus interruptus (Ci) transcription factors. Hh proteins are secreted and spread through tissue, despite becoming covalently linked to sterol during processing. Multiple mechanisms have been proposed to release Hh proteins in distinct forms; in Drosophila, lipoproteins facilitate long-range Hh mobilization but also contain lipids that repress the pathway. Here, we show that mammalian lipoproteins have conserved roles in Sonic Hedgehog (Shh) release and pathway repression. We demonstrate that lipoprotein-associated forms of Hh and Shh specifically block lipoprotein-mediated pathway inhibition. We also identify a second conserved release form that is not sterol-modified and can be released independently of lipoproteins (Hh-N*/Shh-N*). Lipoprotein-associated Hh/Shh and Hh-N*/Shh-N* have complementary and synergistic functions. In Drosophila wing imaginal discs, lipoprotein-associated Hh increases the amount of full-length Ci, but is insufficient for target gene activation. However, small amounts of non-sterol-modified Hh synergize with lipoprotein-associated Hh to fully activate the pathway and allow target gene expression. The existence of Hh secretion forms with distinct signaling activities suggests a novel mechanism for generating a diversity of Hh responses. PMID:23554573

  2. Identification of a phosphorylation-dependent nuclear localization motif in interferon regulatory factor 2 binding protein 2.

    Directory of Open Access Journals (Sweden)

    Allen C T Teng

    Full Text Available BACKGROUND: Interferon regulatory factor 2 binding protein 2 (IRF2BP2 is a muscle-enriched transcription factor required to activate vascular endothelial growth factor-A (VEGFA expression in muscle. IRF2BP2 is found in the nucleus of cardiac and skeletal muscle cells. During the process of skeletal muscle differentiation, some IRF2BP2 becomes relocated to the cytoplasm, although the functional significance of this relocation and the mechanisms that control nucleocytoplasmic localization of IRF2BP2 are not yet known. METHODOLOGY/PRINCIPAL FINDINGS: Here, by fusing IRF2BP2 to green fluorescent protein and testing a series of deletion and site-directed mutagenesis constructs, we mapped the nuclear localization signal (NLS to an evolutionarily conserved sequence (354ARKRKPSP(361 in IRF2BP2. This sequence corresponds to a classical nuclear localization motif bearing positively charged arginine and lysine residues. Substitution of arginine and lysine with negatively charged aspartic acid residues blocked nuclear localization. However, these residues were not sufficient because nuclear targeting of IRF2BP2 also required phosphorylation of serine 360 (S360. Many large-scale phosphopeptide proteomic studies had reported previously that serine 360 of IRF2BP2 is phosphorylated in numerous human cell types. Alanine substitution at this site abolished IRF2BP2 nuclear localization in C(2C(12 myoblasts and CV1 cells. In contrast, substituting serine 360 with aspartic acid forced nuclear retention and prevented cytoplasmic redistribution in differentiated C(2C(12 muscle cells. As for the effects of these mutations on VEGFA promoter activity, the S360A mutation interfered with VEGFA activation, as expected. Surprisingly, the S360D mutation also interfered with VEGFA activation, suggesting that this mutation, while enforcing nuclear entry, may disrupt an essential activation function of IRF2BP2. CONCLUSIONS/SIGNIFICANCE: Nuclear localization of IRF2BP2 depends on

  3. 甾体衍生物的合成%SYNTHESIS OF STEROL DERIVATIVES BASED ON STEROL METHYLTRANSFERASE ENZYME

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To study on sterol methytranferase enzyme. METHODS:Target compounds were synthesized from cycloartenoland 24(28)-methylenecycloartenol extracted from γ-oryzanol. RESULTS: 11 sterol derivatives were successfully synthesized. CONCLUSIONS:The target compounds were purified by HPLC and their structures were confirmed by NMR and GC/MS. The methods are simple and operable.%目的:研究甾体甲基化转移酶。方法:从γ-oryzanol提取的cycloartenol和 24(28)-methylenecycloartenol为初始原料合成目标化合物。结果:成功地合成了11个甾体衍生物。结论:目标化合物均经HPLC 纯化;结构均经NMR和GC/MS确证,方法简便易行。

  4. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast

    DEFF Research Database (Denmark)

    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D.

    2014-01-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been...... implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found...... that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S...

  5. Absence of sterols constrains food quality of cyanobacteria for an invasive freshwater bivalve.

    Science.gov (United States)

    Basen, Timo; Rothhaupt, Karl-Otto; Martin-Creuzburg, Dominik

    2012-09-01

    The accumulation of cyanobacterial biomass may severely affect the performance of aquatic consumers. Here, we investigated the role of sterols in determining the food quality of cyanobacteria for the invasive clam Corbicula fluminea, which has become a common benthic invertebrate in many freshwater ecosystems throughout the world. In standardized growth experiments, juvenile clams were fed mixtures of different cyanobacteria (Anabaena variabilis, Aphanothece clathrata, Synechococcus elongatus) or sterol-containing eukaryotic algae (Cryptomonas sp., Nannochloropsis limnetica, Scenedesmus obliquus). In addition, the cyanobacterial food was supplemented with different sterols. We provide evidence that somatic growth of C. fluminea on cyanobacterial diets is constrained by the absence of sterols, as indicated by a growth-enhancing effect of sterol supplementation. Thus, our findings contribute to our understanding of the consequences of cyanobacterial mass developments for benthic consumers and highlight the importance of considering sterols as potentially limiting nutrients in aquatic food webs.

  6. Functional characterization of a C-4 sterol methyl oxidase from the endomycorrhizal fungus Glomus intraradices.

    Science.gov (United States)

    Oger, Elodie; Ghignone, Stefano; Campagnac, Estelle; Fontaine, Joël; Grandmougin-Ferjani, Anne; Lanfranco, Luisa

    2009-01-01

    Sterols are crucial components of eukaryotic membranes that control membrane fluidity and permeability. They play an important role in cell signaling, polarity and sorting. Since many steps in the pathway are essential, sterol biosynthesis inhibitors (SBI) are widely used as antifungal agents. This work reports the identification and the characterization of a C-4 sterol methyl oxidase (SMO), the first gene involved in the sterol biosynthetic pathway, so far described from an arbuscular mycorrhizal fungus. The sequence, called GintSMO, shows a primary structure, a hydrophobicity profile and a pattern of histidine-rich motifs which are typical of C-4 methyl sterol oxidases. The complementation assay in a Saccharomyces cerevisiae mutant strain demonstrates that GintSMO encodes a functional SMO. Changes in GintSMO transcript levels and in the amount of the sterol precursor squalene were observed in in vitro grown extraradical structures exposed to the fenpropimorph SBI fungicide.

  7. LGP2 downregulates interferon production during infection with seasonal human influenza A viruses that activate interferon regulatory factor 3.

    Science.gov (United States)

    Malur, Meghana; Gale, Michael; Krug, Robert M

    2012-10-01

    LGP2, a member of the RIG-I-like receptor family, lacks the amino-terminal caspase activation recruitment domains (CARDs) required for initiating the activation of interferon regulatory factor 3 (IRF3) and interferon (IFN) transcription. The role of LGP2 in virus infection is controversial, and the only LGP2 experiments previously carried out with mammalian influenza A viruses employed an attenuated, mouse-adapted H1N1 A/PR/8/34 (PR8) virus that does not encode the NS1 protein. Here we determine whether LGP2 has a role during infection with wild-type, nonattenuated influenza A viruses that have circulated in the human population, specifically two types of seasonal influenza A viruses: (i) H3N2 and H1N1 viruses that activate IRF3 and IFN transcription and (ii) recent H1N1 viruses that block these two activations. In human cells infected with an H3N2 virus that activates IRF3, overexpression of LGP2 or its repressor domain decreased STAT1 activation and IFN-β transcription approximately 10-fold. Overexpression of LGP2 also caused a 10-fold decrease of STAT1 activation during infection with other seasonal influenza A viruses that activate IRF3. Using LGP2(+/+) and LGP2(-/-) mouse cells, we show that endogenous LGP2 decreased IFN production during H3N2 virus infection 3- to 4-fold. In contrast, in both mouse and human cells infected with H1N1 viruses that do not activate IRF3, LGP2 had no detectable role. These results demonstrate that LGP2 downregulates IFN production during infection by seasonal influenza A viruses that activate IRF3 and IFN transcription. It is intriguing that LGP2, a host protein induced during influenza A virus infection, downregulates the host antiviral IFN response.

  8. Relationship between interferon regulatory factor 4 genetic polymorphisms, measures of sun sensitivity and risk for non-Hodgkin lymphoma.

    Science.gov (United States)

    Gathany, Allison H; Hartge, Patricia; Davis, Scott; Cerhan, James R; Severson, Richard K; Cozen, Wendy; Rothman, Nathaniel; Chanock, Stephen J; Wang, Sophia S

    2009-10-01

    Sun exposure and sensitivity, including pigmentation, are associated with risk for non-Hodgkin lymphoma (NHL). One variant in the immune regulatory factor 4 (IRF4) gene (rs12203592) is associated with pigmentation, and a different IRF4 variant (rs12211228) is associated with NHL risk. We evaluated the independent roles of these IRF4 polymorphisms and sun sensitivity in mediating NHL risk and explored whether they are confounded or modified by each other. Genotyping of tag single nucleotide polymorphisms (SNPs) in the IRF4 gene was conducted in 990 NHL cases and 828 controls from a multi-center US study. Measures of sun sensitivity and exposure were ascertained from computer-assisted personal interviews. We used logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI) for NHL in relation to sun exposures, sun exposures in relation to IRF4 genotypes, and NHL in relation to sun exposures. We further assessed the effects of sun exposures in relation to IRF4 genotypes. As previously reported, we found significant associations between IRF4 rs12211228 and NHL and between hair and eye color and NHL. The IRF4 rs12203592 polymorphism (CT/TT genotype) was statistically significantly associated with eye color and particularly with hair color (OR(Light Blonde) = 0.24, 95% CI = 0.11-0.50, overall Chi square p = 0.0002). Analysis of joint effects between eye and hair color with the IRF4 rs12203592 SNP did not reveal statistically significant p-interactions although NHL risk did decline with lighter hair color and presence of the variant IRF4 rs12203592 allele, compared to those without a variant allele and with black/brown hair color. Our data do not statistically support a joint effect between IRF4 and sun sensitivity in mediating risk for NHL. Further evaluation of joint effects in other and larger populations is warranted.

  9. Dual functions of interferon regulatory factors 7C in Epstein-Barr virus-mediated transformation of human B lymphocytes.

    Directory of Open Access Journals (Sweden)

    Yong Zhao

    Full Text Available Epstein-Barr virus (EBV infection is associated with several human malignancies. Interferon (IFN regulatory factor 7 (IRF-7 has several splicing variants, and at least the major splicing variant (IRF-7A has oncogenic potential and is associated with EBV transformation processes. IRF-7C is an alternative splicing variant with only the DNA-binding domain of IRF-7. Whether IRF-7C is present under physiological conditions and its functions in viral transformation are unknown. In this report, we prove the existence of IRF-7C protein and RNA in certain cells under physiological conditions, and find that high levels of IRF-7C are associated with EBV transformation of human primary B cells in vitro as well as EBV type III latency. EBV latent membrane protein 1 (LMP-1 stimulates IRF-7C expression in B lymphocytes. IRF-7C has oncogenic potential in rodent cells and partially restores the growth properties of EBV-transformed cells under a growth-inhibition condition. A tumor array experiment has identified six primary tumor specimens with high levels of IRF-7C protein--all of them are lymphomas. Furthermore, we show that the expression of IRF-7C is apparently closely associated with other IRF-7 splicing variants. IRF-7C inhibits the function of IRF-7 in transcriptional regulation of IFN genes. These data suggest that EBV may use splicing variants of IRF-7 for its transformation process in two strategies: to use oncogenic properties of various IRF-7 splicing variants, but use one of its splicing variants (IRF-7C to block the IFN-induction function of IRF-7 that is detrimental for viral transformation. The work provides a novel relation of host/virus interactions, and has expanded our knowledge about IRFs in EBV transformation.

  10. Sterol O-Acyltransferase 2-Driven Cholesterol Esterification Opposes Liver X Receptor-Stimulated Fecal Neutral Sterol Loss.

    Science.gov (United States)

    Warrier, Manya; Zhang, Jun; Bura, Kanwardeep; Kelley, Kathryn; Wilson, Martha D; Rudel, Lawrence L; Brown, J Mark

    2016-02-01

    Statin drugs have proven a successful and relatively safe therapy for the treatment of atherosclerotic cardiovascular disease (CVD). However, even with the substantial low-density lipoprotein (LDL) cholesterol lowering achieved with statin treatment, CVD remains the top cause of death in developed countries. Selective inhibitors of the cholesterol esterifying enzyme sterol-O acyltransferase 2 (SOAT2) hold great promise as effective CVD therapeutics. In mouse models, previous work has demonstrated that either antisense oligonucleotide (ASO) or small molecule inhibitors of SOAT2 can effectively reduce CVD progression, and even promote regression of established CVD. Although it is well known that SOAT2-driven cholesterol esterification can alter both the packaging and retention of atherogenic apoB-containing lipoproteins, here we set out to determine whether SOAT2-driven cholesterol esterification can also impact basal and liver X receptor (LXR)-stimulated fecal neutral sterol loss. These studies demonstrate that SOAT2 is a negative regulator of LXR-stimulated fecal neutral sterol loss in mice.

  11. [Sources, Migration and Conversion of Dissolved Sterols in Qingmuguan Underground River].

    Science.gov (United States)

    Liang, Zuo-bing; Shen, Li-cheng; Sun, Yu-chuan; Wang, Zun-bo; Jiang, Ze-li; Zhang Mei; LIAO, Yu; Xie, Zheng-lan; Zhang, Yuan-zhu

    2015-11-01

    Water samples were collected from the Qinmuguan underground river from July to November in 2013. By gas chromatography-mass spectrometer (GC-MS), dissolved sterols were quantitatively analyzed. The results show that the average variation content of dissolved sterols ranges from 415 to 629 ng x L(-1), with the increasing migration distance of dissolved sterols in underground river, its contents are decreased. Between the inlet and outlet of Qingmuguan underground river, the average variation contents of dissolved sterol are between 724 and 374 ng x L(-1), and the average variation ratios of the content of stigmasterol with cholesterol range from 0.29 to 0.12. In short, their values are decreased accompanied by the increasing migration distance of underground river. The composing component in dissolved sterols varied differently between July to December, and the main component of dissolved sterols is cholesterin, the ratios of the content of dissolved sterols with cholesterin to the total dissolved sterols range from 37.30% to 94.85%. In addition, the ratios of the content of dissolved sterols with coprostanol to cholesterin, coprostanol to cholesterin are below 0.2 respectively, indicating the water quality of underground river is not contaminated by domestic sewage, but with the passage of time water quality tends to deterioration.

  12. Selective visualization of fluorescent sterols in Caenorhabditis elegans by bleach-rate-based image segmentation

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Landt Larsen, Ane; Færgeman, Nils J.

    2010-01-01

    The nematode Caenorhabditis elegans is a genetically tractable model organism to investigate sterol transport. In vivo imaging of the fluorescent sterol, dehydroergosterol (DHE), is challenged by C. elegans' high autofluorescence in the same spectral region as emission of DHE. We present a method...... autofluorescence and compare our method with three-photon excitation microscopy of sterol in selected tissues. Bleach-rate-based UV-WF imaging is a useful tool for genetic screening experiments on sterol transport, as exemplified by RNA interference against the rme-2 gene coding for the yolk receptor and for worm...

  13. Propiconazole inhibits the sterol 14α-demethylase in Glomus irregulare like in phytopathogenic fungi.

    Science.gov (United States)

    Calonne, Maryline; Sahraoui, Anissa Lounès-Hadj; Campagnac, Estelle; Debiane, Djouher; Laruelle, Frédéric; Grandmougin-Ferjani, Anne; Fontaine, Joël

    2012-04-01

    The increasing concentrations impact (0.02, 0.2 and 2 mg L(-1)) of a Sterol Biosynthesis Inhibitor (SBI) fungicide, propiconazole, was evaluated on development and sterol metabolism of two non-target organisms: mycorrhizal or non-mycorrhizal transformed chicory roots and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare using monoxenic cultures. In this work, we provide the first evidence of a direct impact of propiconazole on the AMF by disturbing its sterol metabolism. A significant decrease in end-products sterols contents (24-methylcholesterol and in 24-ethylcholesterol) was observed concomitantly to a 24-methylenedihydrolanosterol accumulation indicating the inhibition of a key enzyme in sterol biosynthesis pathway, the sterol 14α-demethylase like in phytopathogenic fungi. A decrease in end-product sterol contents in propiconazole-treated roots was also observed suggesting a slowing down of the sterol metabolism in plant. Taken together, our findings suggest that the inhibition of the both AM symbiotic partners development by propiconazole results from their sterol metabolism alterations.

  14. Plant sterols, cholesterol precursors and oxysterols: Minute concentrations-Major physiological effects.

    Science.gov (United States)

    Olkkonen, Vesa M; Gylling, Helena; Ikonen, Elina

    2017-05-01

    Non-cholesterol sterols are present in our body at very low concentrations as compared to cholesterol. Small changes in the structure of sterol molecules confer them highly distinct biological activities. The best-known example are steroid hormones derived from cholesterol. During the past decade, our knowledge of also other biomolecules related to or derived from cholesterol, particularly plant sterols, biosynthetic precursors of cholesterol, and oxysterols, has expanded rapidly. In this review article we recapitulate the latest insights into the properties and physiological activities of these non-cholesterol sterols, as well as their importance in disease processes and potential as diagnostic biomarkers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The changes of negative-regulatory factors A20, IRF-4 and TRAF4 of toll-like receptor signal pathways in immunological pathogenesis of Kawasaki disease

    Institute of Scientific and Technical Information of China (English)

    GUO BING WANG; CHENG RONG LI; JUN YANG; YING ZHU

    2007-01-01

    To investigate the role of negative-regulatory factors A20, IRF-4 and TRAF4 of the toll-like receptor (TLR) signal pathways in immunological pathogenesis of Kawasaki disease (KD), 48 children with Kawasaki disease, 16 children with infectious disease (ID) and 16 age-matched healthy children were studied. Reverse-transcription PCR (RT-PCR) and real-time PCR were used to evaluate the expression levels of negative-regulatory and effective factors in toll-like receptor 4 (TLR4) signal pathways and proinflammatory factors in peripheral blood monocyte/maerophage (MC). In this study, expression levels of TLR4, MD-2, MyD88, IRAK-4, TRAF6, TAK1, TAB1 and TAB2 Mrna in KD group were detected to be elevated significantly during acute phase of KD. Transcription levels of negative-regulatory factors A20, IRF-4 and TRAF4 Mrna in KD or ID patients increased remarkably. However, expressions of IRF-4 and TRAF4 in KD patients were detected to be lower than that in ID patients, except that transcription levels of A20 were found to be higher than that in ID patients. Simultaneously, expressions of proinflammatory cytokines such as L-1β, IL-6 and TNF-α in KD patients were significantly elevated compared with those in ID patients. Furthermore, it was found that stimulation of lipopelysaccharide (LPS)remarkably up-regulated the expressions of negative-regulatory factors A20, IRF-4 and TRAF4 in KD patients or healthy volunteers. The Mrna levels of all the three factors in KD patients were found to be lower than that in the latter. In addition, transcription levels of IRF-4 and TRAF4 in KD patients with coronary artery lesion (KD-CAL+ ) were detected to be lower than those in KD patients without coronary artery lesion (KD-CAL-) during acute phase, while that of A20 in KD-CAL+ group were lower than that in the latter. And the levels of expressions of proinflammatory eytokines in KD-CAL+ group were found to be higher than those in KD-CAL- group ( P<0.01 ). These findings suggest that

  16. A functional SNP in the regulatory region of the decay-accelerating factor gene associates with extraocular muscle pareses in myasthenia gravis

    OpenAIRE

    Heckmann, J M; Uwimpuhwe, H; Ballo, R; Kaur, M.; Bajic, V.B.; Prince, S.

    2009-01-01

    Complement activation in myasthenia gravis (MG) may damage muscle endplate and complement regulatory proteins such as decay-accelerating factor (DAF) or CD55 may be protective. We hypothesize that the increased prevalence of severe extraocular muscle (EOM) dysfunction among African MG subjects reported earlier may result from altered DAF expression. To test this hypothesis, we screened the DAF gene sequences relevant to the classical complement pathway and found an association between myasthe...

  17. Clearance of Apoptotic Cells by Macrophages Induces Regulatory Phenotype and Involves Stimulation of CD36 and Platelet-Activating Factor Receptor

    Directory of Open Access Journals (Sweden)

    Matheus Ferracini

    2013-01-01

    Full Text Available Phagocytosis of apoptotic cells (efferocytosis induces macrophage differentiation towards a regulatory phenotype (IL-10high/IL-12p40low. CD36 is involved in the recognition of apoptotic cells (AC, and we have shown that the platelet-activating factor receptor (PAFR is also involved. Here, we investigated the contribution of PAFR and CD36 to efferocytosis and to the establishment of a regulatory macrophage phenotype. Mice bone marrow-derived macrophages were cocultured with apoptotic thymocytes, and the phagocytic index was determined. Blockage of PAFR with antagonists or CD36 with specific antibodies inhibited the phagocytosis of AC (~70–80%. Using immunoprecipitation and confocal microscopy, we showed that efferocytosis increased the CD36 and PAFR colocalisation in the macrophage plasma membrane; PAFR and CD36 coimmunoprecipitated with flotillin-1, a constitutive lipid raft protein, and disruption of these membrane microdomains by methyl-β-cyclodextrin reduced AC phagocytosis. Efferocytosis induced a pattern of cytokine production, IL-10high/IL-12p40low, that is, characteristic of a regulatory phenotype. LPS potentiated the efferocytosis-induced production of IL-10, and this was prevented by blocking PAFR or CD36. It can be concluded that phagocytosis of apoptotic cells engages CD36 and PAFR, possibly in lipid rafts, and this is required for optimal efferocytosis and the establishment of the macrophage regulatory phenotype.

  18. Effects of dietary plant meal and soya-saponin supplementation on intestinal and hepatic lipid droplet accumulation and lipoprotein and sterol metabolism in Atlantic salmon (Salmo salar L.).

    Science.gov (United States)

    Gu, Min; Kortner, Trond M; Penn, Michael; Hansen, Anne Kristine; Krogdahl, Åshild

    2014-02-01

    Altered lipid metabolism has been shown in fish fed plant protein sources. The present study aimed to gain further insights into how intestinal and hepatic lipid absorption and metabolism are modulated by plant meal (PM) and soya-saponin (SA) inclusion in salmon feed. Post-smolt Atlantic salmon were fed for 10 weeks one of four diets based on fishmeal or PM, with or without 10 g/kg SA. PM inclusion resulted in decreased growth performance, excessive lipid droplet accumulation in the pyloric caeca and liver, and reduced plasma cholesterol levels. Intestinal and hepatic gene expression profiling revealed an up-regulation of the expression of genes involved in lipid absorption and lipoprotein (LP) synthesis (apo, fatty acid transporters, microsomal TAG transfer protein, acyl-CoA cholesterol acyltransferase, choline kinase and choline-phosphate cytidylyltransferase A), cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase) and associated transcription factors (sterol regulatory element-binding protein 2 and PPARγ). SA inclusion resulted in reduced body pools of cholesterol and bile salts. The hepatic gene expression of the rate-limiting enzyme in bile acid biosynthesis (cytochrome P450 7A1 (cyp7a1)) as well as the transcription factor liver X receptor and the bile acid transporter abcb11 (ATP-binding cassette B11) was down-regulated by SA inclusion. A significant interaction was observed between PM inclusion and SA inclusion for plasma cholesterol levels. In conclusion, gene expression profiling suggested that the capacity for LP assembly and cholesterol synthesis was up-regulated by PM exposure, probably as a compensatory mechanism for excessive lipid droplet accumulation and reduced plasma cholesterol levels. SA inclusion had hypocholesterolaemic effects on Atlantic salmon, accompanied by decreased bile salt metabolism.

  19. The Transcription Factor Interferon Regulatory Factor-1 (IRF1) Plays a Key Role in the Terminal Effector Pathways of Human Preterm Labor.

    Science.gov (United States)

    Lim, Ratana; Tran, Ha Thi; Liong, Stella; Barker, Gillian; Lappas, Martha

    2016-02-01

    Preterm birth is the largest single cause of neonatal death and morbidity. By activating cytokine- and Toll-like receptor (TLR)-signaling pathways, infection and/or inflammation are strongly associated with preterm delivery. Interferon regulatory factor-1 (IRF1) is an important regulator of the inflammatory response. The aims of this study were to establish the effect of 1) labor on IRF1 expression in human fetal membranes and myometrium, 2) prolabor mediators on IRF1 expression and activity, and 3) IRF1 small interfering RNA on the expression of prolabor mediators. IRF1 expression was higher in fetal membranes and myometrium after spontaneous term labor and in preterm fetal membranes with infection. The proinflammatory cytokine IL1B, the bacterial product fsl-1, and viral analog polyinosinic:polycytidylic acid (poly [I:C]) significantly increased IRF1 mRNA expression and transcriptional activity in human primary myometrial cells. In addition, IL1B increased IRF1 activity in primary amnion cells. IRF1 silencing in myometrial cells decreased IL1B-, fsl-1-, and poly (I:C)-induced cytokine (IL6, TNF, IL1B) and chemokine (CXCL8, CCL2) mRNA expression and IL6, CXCL8, and CCL2 release. IL1B-, fsl-1-, and poly (I:C)-induced PTGS2 mRNA expression and IL1B-induced prostaglandin release was also decreased by IRF1 silencing. In conclusion, IRF1 upregulation in fetal membranes and myometrium after term labor indicates a proinflammatory role for IRF1 in human parturition. IRF1 is involved in TLR- and cytokine-mediated signaling in human myometrium. These data provide new insights into the mechanisms associated with inflammation- and infection-associated preterm birth. IRF1 inhibitors as therapeutics for the management of spontaneous preterm birth warrants further investigation. © 2016 by the Society for the Study of Reproduction, Inc.

  20. Human herpesvirus 8 interferon regulatory factor-mediated BH3-only protein inhibition via Bid BH3-B mimicry.

    Directory of Open Access Journals (Sweden)

    Young Bong Choi

    Full Text Available Viral replication efficiency is in large part governed by the ability of viruses to counteract pro-apoptotic signals induced by infection of host cells. For HHV-8, viral interferon regulatory factor-1 (vIRF-1 contributes to this process in part via inhibitory interactions with BH3-only protein (BOP Bim, recently identified as an interaction partner of vIRF-1. Here we recognize that the Bim-binding domain (BBD of vIRF-1 resembles a region (BH3-B of Bid, another BOP, which interacts intramolecularly with the functional BH3 domain of Bid to inhibit it pro-apoptotic activity. Indeed, vIRF-1 was found to target Bid in addition to Bim and to interact, via its BBD region, with the BH3 domain of each. In functional assays, BBD could substitute for BH3-B in the context of Bid, to suppress Bid-induced apoptosis in a BH3-binding-dependent manner, and vIRF-1 was able to protect transfected cells from apoptosis induced by Bid. While vIRF-1 can mediate nuclear sequestration of Bim, this was not the case for Bid, and inhibition of Bid and Bim by vIRF-1 could occur independently of nuclear localization of the viral protein. Consistent with this finding, direct BBD-dependent inactivation by vIRF-1 of Bid-induced mitochondrial permeabilization was demonstrable in vitro and isolated BBD sequences were also active in this assay. In addition to Bim and Bid BH3 domains, BH3s of BOPs Bik, Bmf, Hrk, and Noxa also were found to bind BBD, while those of both pro- and anti-apoptotic multi-BH domain Bcl-2 proteins were not. Finally, the significance of Bid to virus replication was demonstrated via Bid-depletion in HHV-8 infected cells, which enhanced virus production. Together, our data demonstrate and characterize BH3 targeting and associated inhibition of BOP pro-apoptotic activity by vIRF-1 via Bid BH3-B mimicry, identifying a novel mechanism of viral evasion from host cell defenses.

  1. Impact of ice melting on distribution of particulate sterols in glacial fjords of Chilean Patagonia

    Science.gov (United States)

    Gutiérrez, Marcelo H.; Riquelme, Pablo; Pantoja, Silvio

    2016-04-01

    We analyzed variability in abundance and composition of sterols in waters of the fjord adjacent to glacier Jorge Montt, one of the fastest retreated glaciers in Patagonian Icefields. The study was carried out between August 2012 and November 2013 under different meltwater scenarios. Distribution of sterols in surface and bottom waters was determined by Gas Chromatography coupled to Mass Spectrometry. Sterol concentration ranged from 18 to 1726 ng/L in surface and bottom waters and was positive correlated with chlorophyll-a concentration. Under high melting conditions in austral summer, surface meltwaters showed high concentrations of sterols and were dominated by methylene-cholesterol, a representative sterol of centric diatoms. In the area near open ocean and in austral autumn, winter and spring in proglacial fjord, lower sterol concentrations in surface waters were accompanied by other microalgae sterols and an increase in relative abundance of plant sterols, evidencing a different source of organic matter. In autumn, when high meltwater flux was also evidenced, presence of stanols and an uncommon tri-unsaturated sterol suggests influence of meltwaters in composition of sterols in the downstream fjord. We conclude that ice melting can modify sterol composition by setting conditions for development of a singular phytoplankton population able to thrive in surface meltwater and by carrying glacier organic matter into Patagonian glacial fjords. In projected ice melting scenario, these changes in organic matter quantity and quality can potentially affect availability of organic substrates for heterotrophic activity and trophic status of glacial fjords. This research was funded by COPAS Sur-Austral (PFB-31)

  2. A Novel C30 Sterol from Porana racemosa

    Institute of Scientific and Technical Information of China (English)

    LIBo-Gang; CHENBin; WANGDing-Yong; YEQi; ZHANGGuo-Lin

    2004-01-01

    A novel C30 sterol, (22E, 24ξ)-24-n-propylcholest-7, 22-dien-3β-ol (racemosol, 1), along withscopoletin (2), scopolin (3), umbelliferone (4), methylβ-D-frucopyranoside (5), syringaresinol-4-O-β-D-glucopyranoside (6), quercetin-3-O-β-D-glucopyranoside (7), quercetin-3-O-α-L-rhamnopyranoside (8),eupatilin (9), kaempferol-3-O-β-D-glucopyranoside (10) and (E)-N-2-(2,3-dihydroxyphenyl) ethyl cinnamamide(11), was isolated from the whole plants of Porana racemosa Roxb. Their structures were elucidatedpredominantly by spectral evidence.

  3. A functional SNP in the regulatory region of the decay-accelerating factor gene associates with extraocular muscle pareses in myasthenia gravis

    KAUST Repository

    Heckmann, J M

    2009-08-13

    Complement activation in myasthenia gravis (MG) may damage muscle endplate and complement regulatory proteins such as decay-accelerating factor (DAF) or CD55 may be protective. We hypothesize that the increased prevalence of severe extraocular muscle (EOM) dysfunction among African MG subjects reported earlier may result from altered DAF expression. To test this hypothesis, we screened the DAF gene sequences relevant to the classical complement pathway and found an association between myasthenics with EOM paresis and the DAF regulatory region c.-198CG SNP (odds ratio8.6; P0.0003). This single nucleotide polymorphism (SNP) results in a twofold activation of a DAF 5?-flanking region luciferase reporter transfected into three different cell lines. Direct matching of the surrounding SNP sequence within the DAF regulatory region with the known transcription factor-binding sites suggests a loss of an Sp1-binding site. This was supported by the observation that the c.-198CG SNP did not show the normal lipopolysaccharide-induced DAF transcriptional upregulation in lymphoblasts from four patients. Our findings suggest that at critical periods during autoimmune MG, this SNP may result in inadequate DAF upregulation with consequent complement-mediated EOM damage. Susceptible individuals may benefit from anti-complement therapy in addition to immunosuppression. © 2010 Macmillan Publishers Limited. All rights reserved.

  4. A functional SNP in the regulatory region of the decay-accelerating factor gene associates with extraocular muscle pareses in myasthenia gravis.

    Science.gov (United States)

    Heckmann, J M; Uwimpuhwe, H; Ballo, R; Kaur, M; Bajic, V B; Prince, S

    2010-01-01

    Complement activation in myasthenia gravis (MG) may damage muscle endplate and complement regulatory proteins such as decay-accelerating factor (DAF) or CD55 may be protective. We hypothesize that the increased prevalence of severe extraocular muscle (EOM) dysfunction among African MG subjects reported earlier may result from altered DAF expression. To test this hypothesis, we screened the DAF gene sequences relevant to the classical complement pathway and found an association between myasthenics with EOM paresis and the DAF regulatory region c.-198C>G SNP (odds ratio=8.6; P=0.0003). This single nucleotide polymorphism (SNP) results in a twofold activation of a DAF 5'-flanking region luciferase reporter transfected into three different cell lines. Direct matching of the surrounding SNP sequence within the DAF regulatory region with the known transcription factor-binding sites suggests a loss of an Sp1-binding site. This was supported by the observation that the c.-198C>G SNP did not show the normal lipopolysaccharide-induced DAF transcriptional upregulation in lymphoblasts from four patients. Our findings suggest that at critical periods during autoimmune MG, this SNP may result in inadequate DAF upregulation with consequent complement-mediated EOM damage. Susceptible individuals may benefit from anti-complement therapy in addition to immunosuppression.

  5. Effect of Sterol Structure on Chain Ordering of an Unsaturated Phospholipid: A 2H-NMR Study of POPC/Sterol Membranes

    Science.gov (United States)

    Shaghaghi, Mehran; Thewalt, Jenifer; Zuckermann, Martin

    2012-10-01

    The physical properties of biological membranes are considerably altered by the presence of sterols. In particular, sterols help to maintain the integrity of the cell by adjusting the fluidity of the plasma membrane. Cholesterol is in addition an important component of lipid rafts which are hypothesized to compartmentalize the cell membrane surface thereby making it possible for certain proteins to function. Using 2H-NMR spectroscopy, we studied the effect of a series of different sterols on the chain ordering of POPC, an unsaturated phospholipid present in eukaryotic cell membranes. We were able to assigned specific roles to the structural differences between the sterols by comparing the manner in which they affect the average lipid chain conformation of POPC.

  6. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast.

    Science.gov (United States)

    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D; Andersen, Tonni G; Pomorski, Thomas G

    2014-12-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S. cerevisiae requires the presence of serum or albumin for efficient cholesterol uptake. These results suggest that albumin can serve as sterol donor in ABC transporter-dependent sterol uptake, a process potentially important for growth of C. glabrata inside infected humans.

  7. Plant sterol intakes and colorectal cancer risk in the Netherlands : cohort study on diet and cancer

    NARCIS (Netherlands)

    Normén, A.L.; Brants, H.A.M.; Voorrips, L.E.; Andersson, H.A.; Brandt, P.A. van den

    2001-01-01

    Background: Plant sterols in vegetable foods might prevent colorectal cancer. Objective: The objective was to study plant sterol intakes in relation to colorectal cancer risk in an epidemiologic study. Design: The study was performed within the framework of the Netherlands Cohort Study on Diet and C

  8. The biosynthesis, absorption, and origin of cholesterol and plant sterols in the Florida land crab.

    Science.gov (United States)

    Douglass, T S; Connor, W E; Lin, D S

    1981-08-01

    In order to study the biosynthesis, composition, and origin of sterols in the Florida land crabs, Cardisoma guanhumi (Latreille), we fed 17 male crabs either a cholesterol-free or a high cholesterol diet for 2 to 7 weeks. The origin of sterols in these crabs, whether from biosynthesis or from the diet, was determined by tahree procedures: the incorporation of isotopic mevalonate into the cholesterol when the diet was cholesterol-free; the absorption of isotopic cholesterol and sitosterol from the diet; the cholesterol and plant sterol concentrations of hepatopancreas, plasma, and muscle under conditions of cholesterol-free and high cholesterol diets. In addition, the interconversion of cholesterol and sitosterol was investigated. Dietary sterols of plant and animal sources were readily absorbed and provided the major source of sterols for this species of crab. The biosynthesis of cholesterol from mevalonate in this crab was minimal. However, cholesterol was synthesized from dietary sitosterol by dealkylation. Cholesterol and the three plant sterols (24 epsilon-methyl cholesterol, stigmasterol, and sitosterol) were found in the hepatopancreas, plasma, and muscle of the crab. Plant sterols contributed from 9 to 37% of the total sterols in the hepatopancreas, plasma, and muscle of the crabs fed a cholesterol-free diet.

  9. Specific Sterols Required for the Internalization Step of Endocytosis in Yeast

    Science.gov (United States)

    Munn, Alan L.; Heese-Peck, Antje; Stevenson, Brian J.; Pichler, Harald; Riezman, Howard

    1999-01-01

    Sterols are major components of the plasma membrane, but their functions in this membrane are not well understood. We isolated a mutant defective in the internalization step of endocytosis in a gene (ERG2) encoding a C-8 sterol isomerase that acts in the late part of the ergosterol biosynthetic pathway. In the absence of Erg2p, yeast cells accumulate sterols structurally different from ergosterol, which is the major sterol in wild-type yeast. To investigate the structural requirements of ergosterol for endocytosis in more detail, several erg mutants (erg2Δ, erg6Δ, and erg2Δerg6Δ) were made. Analysis of fluid phase and receptor-mediated endocytosis indicates that changes in the sterol composition lead to a defect in the internalization step. Vesicle formation and fusion along the secretory pathway were not strongly affected in the ergΔ mutants. The severity of the endocytic defect correlates with changes in sterol structure and with the abundance of specific sterols in the ergΔ mutants. Desaturation of the B ring of the sterol molecules is important for the internalization step. A single desaturation at C-8,9 was not sufficient to support internalization at 37°C whereas two double bonds, either at C-5,6 and C-7,8 or at C-5,6 and C-8,9, allowed internalization. PMID:10564282

  10. Sterols of the green-pigmented, aberrant plastid dinoflagellate, Lepidodinium chlorophorum (Dinophyceae).

    Science.gov (United States)

    Leblond, Jeffrey D; Lasiter, Andrew D

    2012-01-01

    Lepidodinium chlorophorum is a green-pigmented dinoflagellate with an aberrant, tertiary plastid of chlorophyte ancestry rather than the typical red algal, secondary endosymbiont found in the vast majority of photosynthetic dinoflagellates. To date, only one published study exists on the galactolipids of L. chlorophorum, with nothing known about other lipid classes, including sterols. Our objectives were to examine the sterol composition of L. chlorophorum to determine if it produces any unique sterols with the potential to serve as biomarkers, and to compare it to members of the Chlorophyceae to determine if it has inherited any signature green algal sterols from its chlorophyte-derived endosymbiont. We have found that L. chlorophorum produces 6 sterols, all with a 4α-methyl substituent and none of which are known to occur in the Chlorophyceae. Rather, the sterols produced by L. chlorophorum place it within a group of dinoflagellates that have the common dinoflagellate sterols, dinosterol and dinostanol, as part of their sterol composition. Copyright © 2011 Elsevier GmbH. All rights reserved.

  11. Surfactants and Sterols Concentrations in the Surface Microlayer of the Estuarine Areas of Selangor River, Malaysia

    Science.gov (United States)

    Latif, M. T.; Alsalahi, M. A.; Ali, M. M.; Dominick, D.; Khan, M. F.; Wahid, N. B. A.; Mustaffa, N. I. H.

    2016-02-01

    This study aims to determine the concentration of surfactant and sterols as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. SML samples were collected during different seasons using a rotation drum method. The compositions of surfactants were determined as methylene blue active substances (MBAS) and disulphine blue active substances (DBAS) as anionic and cationic surfactants respectively. The concentration of sterols was determined using a gas chromatography equipped with a flame ionization detector (GC-FID). The results show that the concentrations of surfactants around the estuarine area were dominated by anionic surfactants (MBAS) with average concentrations of 0.39 µmol L-1. .The concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L-1. The surfactants and total sterol concentrations were found to be higher in the wet season compare to dry season. Cholesterol was found to be the most abundant sterols component in the SML of the Selangor River. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).

  12. The use of the Dhcr7 knockout mouse to accurately determine the origin of fetal sterols

    Science.gov (United States)

    Tint, G. S.; Yu, Hongwei; Shang, Quan; Xu, Guorong; Patel, Shailendra B.

    2006-01-01

    Mice with a targeted mutation of 3β-hydroxysterol Δ7-reductase (Dhcr7) that cannot convert 7-dehydrocholesterol to cholesterol were used to identify the origin of fetal sterols. Because their heterozygous mothers synthesize cholesterol normally, virtually all sterols found in a Dhcr7 knockout fetus having a Δ7 or a Δ8 double bond must have been synthesized by the fetus itself but any cholesterol had to have come from the mother. Early in gestation, most fetal sterols were of maternal origin, but at approximately E13–14, in situ synthesis became increasingly important, and by birth, 55–60% of liver and lung sterols had been made by the fetus. In contrast, at E10–11, upon formation of the blood-brain barrier, the brain rapidly became the source of almost all of its own sterols (90% at birth). New, rapid, de novo sterol synthesis in brain was confirmed by the observation that concentrations of C24,25-unsaturated sterols were low in the brains of all very young fetuses but increased rapidly beginning at approximately E11–12. Reduced activity of sterol C24,25-reductase (Dhcr24) in brain, suggested by the abundance of C24,25-unsaturated compounds, seems to be the result of suppressed Dhcr24 expression. The early fetal brain also appears to conserve cholesterol by keeping cholesterol 24-hydroxylase expression low until approximately E18. PMID:16651660

  13. Effect of plant sterols and tannins on Phytophthora ramorum growth and sporulation

    Science.gov (United States)

    The acquisition of plant sterols, mediated via elicitins, is required for growth and sporulation of Phytophthora spp. In this paper, we looked at the interaction between elicitins, sterols, and tannins. When ground leaf tissue was added to growth media, P. ramorum growth and sporulation was greates...

  14. Plasma plant sterols serve as poor markers of cholesterol absorption in man

    NARCIS (Netherlands)

    Jakulj, Lily; Mohammed, Hussein; van Dijk, Theo H.; Boer, Theo; Turner, Scott; Groen, Albert K.; Vissers, Maud N.; Stroes, Erik S. G.

    The validation of the use of plasma plant sterols as a marker of cholesterol absorption is frail. Nevertheless, plant sterol concentrations are routinely used to describe treatment-induced changes in cholesterol absorption. Their use has also been advocated as a clinical tool to tailor

  15. A potential biochemical mechanism underlying the influence of sterol deprivation stress on Caenorhabditis elegans longevity

    Science.gov (United States)

    To investigate the biochemical mechanism for sterol-mediated alteration in aging in Caenorhabditis elegans, we established sterol depletion conditions by treating worms with azacoprostane, which reduced mean lifespan of adult C. elegans by 35%. Proteomic analyses of egg proteins from treated and un...

  16. Sterol ratios as a tool for sewage pollution assessment of river sediments in Serbia.

    Science.gov (United States)

    Matić Bujagić, Ivana; Grujić, Svetlana; Jauković, Zorica; Laušević, Mila

    2016-06-01

    In this work, source pollution tracing of the sediments of the Danube River and its tributaries in Serbia was performed using sterol ratios. Improved liquid chromatography-tandem mass spectrometry method, which enabled complete chromatographic separation of four analytes with identical fragmentation reactions (epicoprostanol, coprostanol, epicholestanol and cholestanol), was applied for the determination of steroid compounds (hormones, human/animal and plant sterols). A widespread occurrence of sterols was identified in all analyzed samples, whereas the only detected hormones were mestranol and 17α-estradiol. A human-sourced sewage marker coprostanol was detected at the highest concentration (up to 1939 ng g(-1)). The ratios between the key sterol biomarkers, as well as the percentage of coprostanol relative to the total sterol amount, were applied with the aim of selecting the most reliable for distinction between human-sourced pollution and the sterols originated from the natural sources in river sediments. The coprostanol/(cholesterol + cholestanol) and coprostanol/epicoprostanol ratios do not distinguish between human and natural sources of sterols in the river sediments in Serbia. The most reliable sterol ratios for the sewage pollution assessment of river sediments in the studied area were found to be coprostanol/(coprostanol + cholestanol), coprostanol/cholesterol and epicoprostanol/coprostanol. For the majority of sediments, human-derived pollution was determined. Two sediment samples were identified as influenced by a combination of human and natural biogenic sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Applying Clustering and Phylogeny Analysis to Study Dinoflagellates based on Sterol Composition.

    Science.gov (United States)

    Sterol compositions of dinoflagellates have been studied for several decades as a means of assessing whether certain species possess unique chemical biomarkers. However, no attempt has been made to compile the results from numerous studies to examine how sterol compositions may relate to the phylog...

  18. Investigations of the capacity of synthesizing 3β-sterols in mollusca—VI. The biosynthesis and composition of 3β-sterols in the neogastropods Purpura lapillus and Murex brandaris

    NARCIS (Netherlands)

    Voogt, P.A.

    1972-01-01

    1. 1. It is shown that Purpura lapillus and Murex brandaris are capable of synthesizing sterols from mevalonate and acetate. The biosynthesis of sterols from acetate proceeds only at a slow rate. This phenomenon is compared with that observed in Natica cataena. 2. 2. The composition of the sterol m

  19. Investigations of the capacity of synthesizing 3β-sterols in mollusca—VI. The biosynthesis and composition of 3β-sterols in the neogastropods Purpura lapillus and Murex brandaris

    NARCIS (Netherlands)

    Voogt, P.A.

    1972-01-01

    1. 1. It is shown that Purpura lapillus and Murex brandaris are capable of synthesizing sterols from mevalonate and acetate. The biosynthesis of sterols from acetate proceeds only at a slow rate. This phenomenon is compared with that observed in Natica cataena. 2. 2. The composition of the sterol m

  20. An Interferon Regulated MicroRNA Provides Broad Cell-Intrinsic Antiviral Immunity through Multihit Host-Directed Targeting of the Sterol Pathway.

    Science.gov (United States)

    Robertson, Kevin A; Hsieh, Wei Yuan; Forster, Thorsten; Blanc, Mathieu; Lu, Hongjin; Crick, Peter J; Yutuc, Eylan; Watterson, Steven; Martin, Kimberly; Griffiths, Samantha J; Enright, Anton J; Yamamoto, Mami; Pradeepa, Madapura M; Lennox, Kimberly A; Behlke, Mark A; Talbot, Simon; Haas, Jürgen; Dölken, Lars; Griffiths, William J; Wang, Yuqin; Angulo, Ana; Ghazal, Peter

    2016-03-01

    In invertebrates, small interfering RNAs are at the vanguard of cell-autonomous antiviral immunity. In contrast, antiviral mechanisms initiated by interferon (IFN) signaling predominate in mammals. Whilst mammalian IFN-induced miRNA are known to inhibit specific viruses, it is not known whether host-directed microRNAs, downstream of IFN-signaling, have a role in mediating broad antiviral resistance. By performing an integrative, systematic, global analysis of RNA turnover utilizing 4-thiouridine labeling of newly transcribed RNA and pri/pre-miRNA in IFN-activated macrophages, we identify a new post-transcriptional viral defense mechanism mediated by miR-342-5p. On the basis of ChIP and site-directed promoter mutagenesis experiments, we find the synthesis of miR-342-5p is coupled to the antiviral IFN response via the IFN-induced transcription factor, IRF1. Strikingly, we find miR-342-5p targets mevalonate-sterol biosynthesis using a multihit mechanism suppressing the pathway at different functional levels: transcriptionally via SREBF2, post-transcriptionally via miR-33, and enzymatically via IDI1 and SC4MOL. Mass spectrometry-based lipidomics and enzymatic assays demonstrate the targeting mechanisms reduce intermediate sterol pathway metabolites and total cholesterol in macrophages. These results reveal a previously unrecognized mechanism by which IFN regulates the sterol pathway. The sterol pathway is known to be an integral part of the macrophage IFN antiviral response, and we show that miR-342-5p exerts broad antiviral effects against multiple, unrelated pathogenic viruses such Cytomegalovirus and Influenza A (H1N1). Metabolic rescue experiments confirm the specificity of these effects and demonstrate that unrelated viruses have differential mevalonate and sterol pathway requirements for their replication. This study, therefore, advances the general concept of broad antiviral defense through multihit targeting of a single host pathway.

  1. Plant sterol ester diet supplementation increases serum plant sterols and markers of cholesterol synthesis, but has no effect on total cholesterol levels.

    Science.gov (United States)

    Weingärtner, Oliver; Bogeski, Ivan; Kummerow, Carsten; Schirmer, Stephan H; Husche, Constanze; Vanmierlo, Tim; Wagenpfeil, Gudrun; Hoth, Markus; Böhm, Michael; Lütjohann, Dieter; Laufs, Ulrich

    2017-05-01

    This double-blind, randomized, placebo-controlled, cross-over intervention-study was conducted in healthy volunteers to evaluate the effects of plant sterol ester supplemented margarine on cholesterol, non-cholesterol sterols and oxidative stress in serum and monocytes. Sixteen volunteers, average age 34 years, with no or mild hypercholesterolemia were subjected to a 4 week period of daily intake of 3g plant sterols per day supplied via a supplemented margarine on top of regular eating habits. After a wash-out period of one week, volunteers switched groups. Compared to placebo, a diet supplementation with plant sterols increased serum levels of plant sterols such as campesterol (+0.16±0.19mg/dL, p=0.005) and sitosterol (+0.27±0.18mg/dL, pcholesterol synthesis such as desmosterol (+0.05±0.07mg/dL, p=0.006) as well as lathosterol (+0.11±0.16mg/dL, p=0.012). Cholesterol serum levels, however, were not changed significantly (+18.68±32.6mg/dL, p=0.052). These findings could not be verified in isolated circulating monocytes. Moreover, there was no effect on monocyte activation and no differences with regard to redox state after plant sterol supplemented diet. Therefore, in a population of healthy volunteers with no or mild hypercholesterolemia, consumption of plant sterol ester supplemented margarine results in increased concentrations of plant sterols and cholesterol synthesis markers without affecting total cholesterol in the serum, activation of circulating monocytes or redox