scholarly journals Positive Regulation of fur Gene Expression via Direct Interaction of Fur in a Pathogenic Bacterium, Vibrio vulnificus

2007 ◽  
Vol 189 (7) ◽  
pp. 2629-2636 ◽  
Author(s):  
Hyun-Jung Lee ◽  
So Hyun Bang ◽  
Kyu-Ho Lee ◽  
Soon-Jung Park
Keyword(s):  
Gene Expression ◽  
Pathogenic Bacteria ◽  
Vibrio Vulnificus ◽  
Iron Concentration ◽  
Direct Interaction ◽  
Repeated Sequence ◽  
Upstream Region ◽  
Fur Protein

ABSTRACT In pathogenic bacteria, the ability to acquire iron, which is mainly regulated by the ferric uptake regulator (Fur), is essential to maintain growth as well as its virulence. In Vibrio vulnificus, a human pathogen causing gastroenteritis and septicemia, fur gene expression is positively regulated by Fur when the iron concentration is limited (H.-J. Lee et al., J. Bacteriol. 185:5891-5896, 2003). Footprinting analysis revealed that an upstream region of the fur gene was protected by the Fur protein from DNase I under iron-depleted conditions. The protected region, from −142 to −106 relative to the transcription start site of the fur gene, contains distinct AT-rich repeats. Mutagenesis of this repeated sequence resulted in abolishment of binding by Fur. To confirm the role of this cis-acting element in Fur-mediated control of its own gene in vivo, fur expression was monitored in V. vulnificus strains using a transcriptional fusion containing the mutagenized Fur-binding site (fur mt::luxAB). Expression of fur mt::luxAB showed that it was not regulated by Fur and was not influenced by iron concentration. Therefore, this study demonstrates that V. vulnificus Fur acts as a positive regulator under iron-limited conditions by direct interaction with the fur upstream region.

scholarly journals hfqPlays Important Roles in Virulence and Stress Adaptation in Cronobacter sakazakii ATCC 29544

2015 ◽  
Vol 83 (5) ◽  
pp. 2089-2098 ◽  
Author(s):  
Seongok Kim ◽  
Hyelyeon Hwang ◽  
Kwang-Pyo Kim ◽  
Hyunjin Yoon ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Soft Agar ◽  
Host Cells ◽  
Neonatal Meningitis ◽  
Animal Cells ◽  
Content Type ◽  
Flagellar Biosynthesis

Cronobacterspp. are opportunistic pathogens that cause neonatal meningitis and sepsis with high mortality in neonates. Despite the peril associated withCronobacterinfection, the mechanisms of pathogenesis are still being unraveled. Hfq, which is known as an RNA chaperone, participates in the interaction with bacterial small RNAs (sRNAs) to regulate posttranscriptionally the expression of various genes. Recent studies have demonstrated that Hfq contributes to the pathogenesis of numerous species of bacteria, and its roles are varied between bacterial species. Here, we tried to elucidate the role of Hfq inC. sakazakiivirulence. In the absence ofhfq,C. sakazakiiwas highly attenuated in disseminationin vivo, showed defects in invasion (3-fold) into animal cells and survival (103-fold) within host cells, and exhibited low resistance to hydrogen peroxide (102-fold). Remarkably, the loss ofhfqled to hypermotility on soft agar, which is contrary to what has been observed in other pathogenic bacteria. The hyperflagellated bacteria were likely to be attributable to the increased transcription of genes associated with flagellar biosynthesis in a strain lackinghfq. Together, these data strongly suggest thathfqplays important roles in the virulence ofC. sakazakiiby participating in the regulation of multiple genes.

Abstract 314: BRaf Plays a Major Role in Gene Expression in Cardiomyocytes in Mouse Hearts in vivo

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Michelle A Hardyman ◽  
Stephen J Fuller ◽  
Daniel N Meijles ◽  
Kerry A Rostron ◽  
Sam J Leonard ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cardiac Hypertrophy ◽  
Cardiac Function ◽  
Left Ventricular ◽  
Braf Mutations ◽  
Gene Markers ◽  
Lv Mass ◽  
Cardiac Volumes

Introduction: Raf kinases lie upstream of ERK1/2 with BRaf being the most highly expressed and having the highest basal activity. V600E BRaf mutations constitutively activate ERK1/2 and are common in cancer. The role of BRaf in the adult heart is yet to be established. ERK1/2 regulate cardiomyocyte gene expression, promoting cardiac hypertrophy and cardioprotection, but effects of ERK1/2 may depend on signal strength. Hypothesis: Our hypotheses are that BRaf is critical in regulating ERK1/2 signaling in cardiomyocytes and, whilst moderate ERK1/2 activity is beneficial, excessive ERK1/2 activity is detrimental to the heart. Methods: We generated heterozygote mice for tamoxifen- (Tam-) inducible cardiomyocyte-specific knockin of V600E in the endogenous BRaf gene. Mice (12 wks) received 2 injections of Tam or vehicle on consecutive days (n=4-10 per group). Kinase activities and mRNA expression were assessed by immunoblotting and qPCR. Echocardiography was performed (Vevo2100). M-mode images (short axis view) were analyzed; data for each mouse were normalized to the mean of 2 baseline controls. Results: V600E knockin did not affect overall BRaf or cRaf levels in mouse hearts, but significantly increased ERK1/2 activities within 48 h (1.51±0.05 fold). Concurrently, mRNAs for hypertrophic gene markers including BNP and immediate early genes (IEGs) increased signficantly. At 72 h, expression of BNP, Fosl1, Myc, Ereg and CTGF increased further, other IEGs (Jun, Fos, Egr1, Atf3) declined, and ANF was upregulated. In contrast, expression of α and β myosin heavy chain mRNAs was substantially downregulated (0.46/0.41±0.05 relative to controls). Within 72 h, left ventricular (LV) mass and diastolic LV wall thickness had increased (1.23±0.05 relative to controls), but cardiac function was severely compromised with significant decreases in ejection fraction and cardiac output (0.53/0.68±0.09 relative to controls) associated with increased LV internal diameters and cardiac volumes. Conclusions: Endogenous cardiomyocyte BRaf is sufficient to activate ERK1/2 in mouse hearts and induce cardiac hypertrophy associated with dynamic temporal changes in gene expression. However, excessive activation of ERK1/2 in isolation is detrimental to cardiac function.

scholarly journals The neutrophil-mobilizing cytokine interleukin-26 in the airways of long-term tobacco smokers

2018 ◽  
Vol 132 (9) ◽  
pp. 959-983 ◽  
Author(s):  
Karlhans Fru Che ◽  
Ellen Tufvesson ◽  
Sara Tengvall ◽  
Elisa Lappi-Blanco ◽  
Riitta Kaarteenaho ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chronic Bronchitis ◽  
Pathogenic Bacteria ◽  
Cell Model ◽  
Water Soluble ◽  
Chronic Obstructive ◽  
Neutrophil Accumulation

Long-term tobacco smokers with chronic obstructive pulmonary disease (COPD) or chronic bronchitis display an excessive accumulation of neutrophils in the airways; an inflammation that responds poorly to established therapy. Thus, there is a need to identify new molecular targets for the development of effective therapy. Here, we hypothesized that the neutrophil-mobilizing cytokine interleukin (IL)-26 (IL-26) is involved in airway inflammation amongst long-term tobacco smokers with or without COPD, chronic bronchitis or colonization by pathogenic bacteria. By analyzing bronchoalveolar lavage (BAL), bronchail wash (BW) and induced sputum (IS) samples, we found increased extracellular IL-26 protein in the airways of long-term smokers in vivo without further increase amongst those with clinically stable COPD. In human alveolar macrophages (AM) in vitro, the exposure to water-soluble tobacco smoke components (WTC) enhanced IL-26 gene and protein. In this cell model, the same exposure increased gene expression of the IL-26 receptor complex (IL10R2 and IL20R1) and nuclear factor κ B (NF-κB); a proven regulator of IL-26 production. In the same cell model, recombinant human IL-26 in vitro caused a concentration-dependent increase in the gene expression of NF-κB and several pro-inflammatory cytokines. In the long-term smokers, we also observed that extracellular IL-26 protein in BAL samples correlates with measures of lung function, tobacco load, and several markers of neutrophil accumulation. Extracellular IL-26 was further increased in long-term smokers with exacerbations of COPD (IS samples), with chronic bronchitis (BAL samples ) or with colonization by pathogenic bacteria (IS and BW samples). Thus, IL-26 in the airways emerges as a promising target for improving the understanding of the pathogenic mechanisms behind several pulmonary morbidities in long-term tobacco smokers.

The calcitonin receptor regulates osteocyte lacunae acidity during lactation in mice

2021 ◽  
Vol 249 (1) ◽  
pp. 31-41
Author(s):  
Rachel A Davey ◽  
Michele V Clarke ◽  
Suzanne B Golub ◽  
Patricia K Russell ◽  
Jeffrey D Zajac
Keyword(s):  
Gene Expression ◽  
Direct Action ◽  
Physiological Role ◽  
Calcitonin Receptor ◽  
Ph Indicator ◽  
Osteocyte Lacunae ◽  
Osteocytic Osteolysis ◽  
Indicator Dye

The physiological role of calcitonin, and its receptor, the CTR (or Calcr), has long been debated. We previously provided the first evidence for a physiological role of the CTR to limit maternal bone loss during lactation in mice by a direct action on osteocytes to inhibit osteocytic osteolysis. We now extend these findings to show that CTR gene expression is upregulated two- to three-fold in whole bone of control mice at the end of pregnancy (E18) and lactation (P21) compared to virgin controls. This was associated with an increase in osteoclast activity evidenced by increases in osteoclast surface/bone surface and Dcstamp gene expression. To investigate the mechanism by which the CTR inhibits osteocytic osteolysis, in vivo acidification of the osteocyte lacunae during lactation (P14 days) was assessed using a pH indicator dye. A lower pH was observed in the osteocyte lacunae of lactating Global-CTRKOs compared to controls and was associated with an increase in the gene expression of ATPase H+ transporting V0 subunit D2 (Atp6v0d2) in whole bone of Global-CTRKOs at the end of lacation (P21). To determine whether the CTR is required for the replacement of mineral within the lacunae post-lactation, lacunar area was determined 3 weeks post-weaning. Comparison of the largest 20% of lacunae by area did not differ between Global-CTRKOs and controls post-lactation. These results provide evidence for CTR activation to inhibit osteocytic osteolysis during lactation being mediated by regulating the acidity of the lacunae microenvironment, whilst the CTR is dispensable for replacement of bone mineral within lacunae by osteocytes post-lactation.

scholarly journals Loss of keratin 6 (K6) proteins reveals a function for intermediate filaments during wound repair

2003 ◽  
Vol 163 (2) ◽  
pp. 327-337 ◽  
Author(s):  
Pauline Wong ◽  
Pierre A. Coulombe
Keyword(s):  
Gene Expression ◽  
Wound Repair ◽  
Tissue Injury ◽  
Blood Clot ◽  
Explant Culture ◽  
Null Mouse ◽  
Actin Organization ◽  
Mammalian Tissues

The ability to heal wounds is vital to all organisms. In mammalian tissues, alterations in intermediate filament (IF) gene expression represent an early reaction of cells surviving injury. We investigated the role of keratin IFs during the epithelialization of skin wounds using a keratin 6α and 6β (K6α/K6β)-null mouse model. In skin explant culture, null keratinocytes exhibit an enhanced epithelialization potential due to increased migration. The extent of the phenotype is strain dependent, and is accompanied by alterations in keratin IF and F-actin organization. However, in wounded skin in vivo, null keratinocytes rupture as they attempt to migrate under the blood clot. Fragility of the K6α/K6β-null epidermis is confirmed when applying trauma to chemically treated skin. We propose that the alterations in IF gene expression after tissue injury foster a compromise between the need to display the cellular pliability necessary for timely migration and the requirement for resilience sufficient to withstand the rigors of a wound site.

scholarly journals PRMT5 Is Required for Bovine Leukemia Virus Infection In Vivo and Regulates BLV Gene Expression, Syncytium Formation, and Glycosylation In Vitro

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 650 ◽  
Author(s):  
Wlaa Assi ◽  
Tomoya Hirose ◽  
Satoshi Wada ◽  
Ryosuke Matsuura ◽  
Shin-nosuke Takeshima ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Molecule ◽  
Bovine Leukemia Virus ◽  
Proviral Load ◽  
Leukemia Virus ◽  
Syncytium Formation ◽  
High Proviral Load

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, which is the most common neoplastic disease of cattle and is closely related to human T-cell leukemia viruses. We investigated the role of a new host protein, PRMT5, in BLV infection. We found that PRMT5 is overexpressed only in BLV-infected cattle with a high proviral load, but not in those with a low proviral load. Furthermore, this upregulation continued to the lymphoma stage. PRMT5 expression was upregulated in response to experimental BLV infection; moreover, PRMT5 upregulation began in an early stage of BLV infection rather than after a long period of proviral latency. Second, siRNA-mediated PRMT5 knockdown enhanced BLV gene expression at the transcript and protein levels. Additionally, a selective small-molecule inhibitor of PRMT5 (CMP5) enhanced BLV gene expression. Interestingly, CMP5 treatment, but not siRNA knockdown, altered the gp51 glycosylation pattern and increased the molecular weight of gp51, thereby decreasing BLV-induced syncytium formation. This was supported by the observation that CMP5 treatment enhanced the formation of the complex type of N-glycan more than the high mannose type. In conclusion, PRMT5 overexpression is related to the development of BLV infection with a high proviral load and lymphoma stage and PRMT5 inhibition enhances BLV gene expression. This is the first study to investigate the role of PRMT5 in BLV infection in vivo and in vitro and to reveal a novel function for a small-molecule compound in BLV-gp51 glycosylation processing.

scholarly journals Foxa3 (HNF-3γ) binds to and activates the rat proglucagon gene promoter but is not essential for proglucagon gene expression

2002 ◽  
Vol 366 (2) ◽  
pp. 633-641 ◽  
Author(s):  
Yuanfang LIU ◽  
Wei SHEN ◽  
Patricia L. BRUBAKER ◽  
Klaus H. KAESTNER ◽  
Daniel J. DRUCKER
Keyword(s):  
Gene Expression ◽  
Cell Lines ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Forkhead Box ◽  
Mild Hypoglycaemia ◽  
Element Binding Protein ◽  
Prolonged Fast

Members of the Forkhead box a (Foxa) transcription factor family are expressed in the liver, pancreatic islets and intestine and both Foxa1 and Foxa2 regulate proglucagon gene transcription. As Foxa proteins exhibit overlapping DNA-binding specificities, we examined the role of Foxa3 [hepatocyte nuclear factor (HNF)-3γ] in control of proglucagon gene expression. Foxa3 was detected by reverse transcriptase PCR in glucagon-producing cell lines and binds to the rat proglucagon gene G2 promoter element in GLUTag enteroendocrine cells. Although Foxa3 increased rat proglucagon promoter activity in BHK fibroblasts, augmentation of Foxa3 expression did not increase proglucagon promoter activity in GLUTag cells. Furthermore, adenoviral Foxa3 expression did not affect endogenous proglucagon gene expression in islet or intestinal endocrine cell lines. Although Foxa3-/- mice exhibit mild hypoglycaemia during a prolonged fast, the levels of proglucagon-derived peptides and proglucagon mRNA transcripts were comparable in tissues from wild-type and Foxa3-/- mice. These findings identify Foxa3 as a member of the proglucagon gene G2 element binding-protein family that, unlike Foxa1, is not essential for control of islet or intestinal proglucagon gene expression in vivo.

A Novel Role of Coagulation Proteases on Viral-Based Gene Transfer Efficacy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 691-691
Author(s):  
Joerg Schuettrumpf ◽  
Jianxiang Zou ◽  
Shin Jen Tai ◽  
Alexander Schlachterman ◽  
Kian Tian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Transfer ◽  
Knockout Mice ◽  
Viral Vectors ◽  
Hemophilia B ◽  
Gene Copy ◽  
Dependent Manner ◽  
Deficient Mice

Abstract Coagulation proteases are crucial for hemostasis and have also been implicated in inflammatory responses, blood vessel formation, and tumor cell metastasis. Cellular responses triggered by proteases are mediated by protease-activated receptors (PAR). Adeno-associated virus (AAV)-2 vectors hold promise for the treatment of several diseases and were already tested in Phase I studies for hemophilia B following intramuscular or hepatic artery deliveries. Previously, we determined an unexpected inhibitory effect (60–70% downregulation) on AAV-2 and adenovirus mediated gene transfer by thrombin- or FXa inhibitors. These results were independent of mouse strain, transgene product, or vector promoter, and gene expression by vectors of alternate serotypes AAV-5 or -8, which do not share cellular receptors with AAV-2, were not affected by any drug. Here we present in vivo evidence of a novel role of coagulation proteases and PARs in modulating gene transfer by viral vectors. We tested AAV-2 gene transfer efficacy in (a) animal models for proteases deficiency [FX and FIX deficient animals], (b) PAR-1 or PAR-2 deficient mice, (c) and following in vivo activation of PARs. FX knockout mice with residual activity of only 1–3% of normal (n=9) were injected with AAV-2-human(h)FIX vector and compared to littermates with FX levels of 50% (n=4). FIX expression levels were 2-fold lower among FX-deficient mice compared to controls (p<0.03). The second model, FIX deficient mice, received AAV expressing α1-antitrypsin (AAT-1). Severe hemophilia B models due to large-gene deletion (n=5) or missense mutation (R180T) in the FIX gene (n=3, <1% FIX) were compared to littermate controls with normal FIX levels (n=6). The results showed that AAT-1 levels among hemophilia B mice were 2-fold lower than in controls (24 vs 48 ng/ml, p<0.05, respectively). Because PAR activation by thrombin enhances αVβ5 (co-receptor for AAV-2 and adenovirus)-dependent cellular function (JBC 276:10952) we hypothesized that PAR modulates AAV-2 gene transfer. Homozygous (−/−) or heterozygous deficient (+/−) PAR-1 (n=24) or PAR-2 (n=25) mice received AAV-2-hF.IX and were compared to littermate controls (+/+). FIX levels among PAR-1 controls (1.9 μg/ml) were comparable to levels obtained among heterozygotes but higher than in homozygotes (1.1 μg/ml, p<0.02). Similarly, PAR-2 deficient mice presented 2-fold lower FIX levels than controls (0.7 vs 1.3 μg/ml, p<0.02) whereas heterozygous mice presented intermediate levels. To further confirm the role of PARs in AAV-2 gene transfer we activated PARs prior to AAV-2 injection. C57BL/6 mice received specific peptide agonists at doses ranging from 10 to 60 μM/kg (n=4 per dose and per peptide) and were compared to controls receiving scramble peptide. FIX levels increased 1.5 to 5-fold in a dose-dependent manner and the activation of PAR-1 and -2 simultaneously was superior to single peptide. Gene copy monitoring revealed low vector uptake by livers of PAR knockout mice while activation of PARs increased uptake. In conclusion, these data demonstrated a novel in vivo role of coagulation proteases and PARs on viral vectors (AAV-2 and adenovirus)-mediated gene expression and provide an alternative target to modulate gene therapy strategies.

Biologic consequences of androgen receptor (AR) activity in MDV3100-resistant LNCaP cells and dependence on AR full length.

2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 74-74
Author(s):  
Yoshiaki Yamamoto ◽  
Yohann Loriot ◽  
Eliana Beraldi ◽  
Tianyuan Zhou ◽  
Youngsoo Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Androgen Receptor ◽  
Cell Growth ◽  
Functional Role ◽  
Full Length ◽  
Lncap Cells ◽  
Exon 1

74 Background: While recent reports link androgen receptor (AR) variants (AR-Vs) to castration resistant prostate cancer (CRPC), the biological significance of AR-Vs in AR-regulated cell survival and proliferation, independent of AR full length (AR-FL), remains controversial. To define the functional role of AR-FL and AR-Vs in MDV3100-resistant (MDV-R), we designed antisense oligonucleotide (ASO) targeting exon 1 and exon 8 in AR to knockdown AR-FL alone or in combination with AR-Vs and examined these effects in MDV-R LNCaP-derived cells in vitro and in vivo. Methods: We generated by selection MDV-R LNCaP-derived sub-lines that uniformly expressed high levels of both AR-FL and AR-V7 compared to CRPC LNCaP xenografts. Cell growth rates, protein and gene expression were analyzed using crystal violet assay, western blotting and real-time PCR, respectively. Exon 1 and 8 AR-ASO were evaluated in MDV-R49F CRPC LNCaP xenografts. Results: AR-V7 was transiently transfected in MDV-R49F cells and differential knockdown of AR-V7 and/or AR-FL by exon 1 versus exon 8 AR-ASO was used to evaluate relative biologic contributions of AR-FL versus AR-V7 in MDV-R LNCaP AR-V7 overexpressing cells. Exon 1 and 8 AR-ASO treatment in these cells similarly decreased prostate-specific antigen (PSA) expression and induced apoptosis as measured by caspase-3 and PARP cleavage and cell growth inhibition. To further define the functional role of AR-Vs in MDV-R LNCaP cells, we used a CE3 siRNA that specifically silenced AR-V7, but not AR-FL in MDV-R LNCaP cells. AR-V7 knockdown did not decrease PSA levels, did not induce apoptosis, and did not inhibit cell growth. In MDV-R LNCaP cells, exon 1 and 8 ASO similarly suppressed cell growth and AR-regulated gene expression in vitro and in vivo. Conclusions: These results indicate that the AR remains an important driver of MDV3100 resistance and, the biologic consequences mainly driven by AR-FL in MDV-R LNCaP models.

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