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  • 1
    Language: English
    In: Molecular microbiology, June 2011, Vol.80(6), pp.1479-95
    Description: The photosynthetic alphaproteobacterium Rhodobacter sphaeroides has to cope with photooxidative stress that is caused by the bacteriochlorophyll a-mediated formation of singlet oxygen ((1)O(2)). Exposure to (1)O(2) induces the alternative sigma factors RpoE and RpoH(II) which then promote transcription of photooxidative stress-related genes, including small RNAs (sRNAs). The ubiquitous RNA chaperone Hfq is well established to interact with and facilitate the base-pairing of sRNAs and target mRNAs to influence mRNA stability and/or translation. Here we report on the pleiotropic phenotype of a Δhfq mutant of R. sphaeroides, which is less pigmented, produces minicells and is more sensitive to (1)O(2). The higher (1)O(2) sensitivity of the Δhfq mutant is paralleled by a reduced RpoE activity and a disordered induction of RpoH(II)-dependent genes. We used co-immunoprecipitation of FLAG-tagged Hfq combined with RNA-seq to identify association of at least 25 sRNAs and of mRNAs encoding cell division proteins and ribosomal proteins with Hfq. Remarkably, 〉 70% of the Hfq-bound sRNAs are (1)O(2)-affected. Proteomics analysis of the Hfq-deficient strain revealed an impact of Hfq on amino acid transport and metabolic functions. Our data demonstrate for the first time an involvement of Hfq in regulation of photosynthesis genes and in the photooxidative stress response.
    Keywords: Gene Expression Regulation, Bacterial ; Oxidative Stress ; Protein Binding ; Bacterial Proteins -- Metabolism ; Host Factor 1 Protein -- Metabolism ; Rhodobacter Sphaeroides -- Metabolism
    ISSN: 0950382X
    E-ISSN: 1365-2958
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  • 2
    In: Nature, 2010, Vol.464(7286), p.250
    Description: Genome sequencing of Helicobacter pylori has revealed the potential proteins and genetic diversity of this prevalent human pathogen, yet little is known about its transcriptional organization and noncoding RNA output. Massively parallel cDNA sequencing (RNA-seq) has been revolutionizing global transcriptomic analysis. Here, using a novel differential approach (dRNA-seq) selective for the 5' end of primary transcripts, we present a genome-wide map of H. pylori transcriptional start sites and operons. We discovered hundreds of transcriptional start sites within operons, and opposite to annotated genes, indicating that complexity of gene expression from the small H. pylori genome is increased by uncoupling of polycistrons and by genome-wide antisense transcription. We also discovered an unexpected number of approximately 60 small RNAs including the epsilon-subdivision counterpart of the regulatory 6S RNA and associated RNA products, and potential regulators of cis- and trans-encoded target messenger RNAs. Our approach establishes a paradigm for mapping and annotating the primary transcriptomes of many living species.
    Keywords: Gene Expression Profiling ; Genome, Bacterial -- Genetics ; Helicobacter Infections -- Microbiology ; Helicobacter Pylori -- Genetics ; RNA, Bacterial -- Genetics;
    ISSN: 0028-0836
    E-ISSN: 14764687
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  • 3
    In: Nature Microbiology, 2016, Vol.2
    Description: Intracellular bacterial pathogens can exhibit large heterogeneity in growth rate inside host cells, with major consequences for the infection outcome. If and how the host responds to this heterogeneity remains poorly understood. Here, we combined a fluorescent reporter of bacterial cell division with single-cell RNA-sequencing analysis to study the macrophage response to different intracellular states of the model pathogen Salmonella enterica serovar Typhimurium. The transcriptomes of individual infected macrophages revealed a spectrum of functional host response states to growing and non-growing bacteria. Intriguingly, macrophages harbouring non-growing Salmonella display hallmarks of the proinflammatory M1 polarization state and differ little from bystander cells, suggesting that non-growing bacteria evade recognition by intracellular immune receptors. By contrast, macrophages containing growing bacteria have turned into an anti-inflammatory, M2-like state, as if fast-growing intracellular Salmonella overcome host defence by reprogramming macrophage polarization. Additionally, our clustering approach reveals intermediate host functional states between these extremes. Altogether, our data suggest that gene expression variability in infected host cells shapes different cellular environments, some of which may favour a growth arrest of Salmonella facilitating immune evasion and the establishment of a long-term niche, while others allow Salmonella to escape intracellular antimicrobial activity and proliferate.
    Keywords: Biology;
    ISBN: 0003971049000
    E-ISSN: 2058-5276
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  • 4
    Language: English
    In: Journal of cellular and molecular medicine, July 2017, Vol.21(7), pp.1394-1410
    Description: The (pro)renin receptor [(P)RR, ATP6AP2] is a multifunctional transmembrane protein that activates local renin-angiotensin systems, but also interacts with Wnt pathways and vacuolar H -ATPase (V-ATPase) during organogenesis. The aim of this study was to characterize the role of ATP6AP2 in the cell cycle in more detail. ATP6AP2 down-regulation by siRNA in renal As4.1 cells resulted in a reduction in the rate of proliferation and a G0/G1 phase cell cycle arrest. We identified a number of novel target genes downstream of ATP6AP2 knock-down that were related to the primary cilium (Bbs-1, Bbs-3, Bbs-7, Rabl5, Ttc26, Mks-11, Mks-5, Mks-2, Tctn2, Nme7) and the cell cycle (Pierce1, Clock, Ppif). Accordingly, the number of cells expressing the primary cilium was markedly increased. We found no indication that these effects were dependent of V-ATPase activity, as ATP6AP2 knock-down did not affect lysosomal pH and bafilomycin A neither influenced the ciliary expression pattern nor the percentage of ciliated cells. Furthermore, ATP6AP2 appears to be essential for mitosis. ATP6AP2 translocated from the endoplasmatic reticulum to mitotic spindle poles (pro-, meta- and anaphase) and the central spindle bundle (telophase) and ATP6AP2 knock-down results in markedly deformed spindles. We conclude that ATP6AP2 is necessary for cell division, cell cycle progression and mitosis. ATP6AP2 also inhibits ciliogenesis, thus promoting proliferation and preventing differentiation.
    Keywords: (P)Rr/Atp6ap2 ; V-Atpase ; Cell Cycle ; Ciliogenesis ; Proliferation ; Cilia -- Genetics ; Organogenesis -- Genetics ; Proton-Translocating Atpases -- Genetics ; Receptors, Cell Surface -- Genetics ; Vacuolar Proton-Translocating Atpases -- Genetics
    ISSN: 15821838
    E-ISSN: 1582-4934
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  • 5
    In: Arteriosclerosis, Thrombosis, and Vascular Biology: Journal of the American Heart Association, 2002, Vol.22(6), pp.914-920
    Description: Inflammatory response and chemotaxis of vascular wall cells play an important pathogenic role in the development of atherosclerosis. Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant for monocytes. Besides the induction of monocyte recruitment, it has been suggested that MCP-1 may directly activate smooth muscle cells. We investigated whether MCP-1 affects the proliferation and cytokine production of human vascular smooth muscle cells (VSMCs) and determined the underlying signal transduction pathways. Stimulation of VSMCs with MCP-1 induced proliferation and resulted in a concentration- and time-dependent release of the proinflammatory cytokine interleukin-6 (IL-6). Pretreatment with pertussis toxin, GF109203X, and pyrrolidine dithiocarbamate inhibited MCP-1–dependent IL-6 release, suggesting the involvement of Gi proteins, protein kinase C, and nuclear factor-κB (NF-κB). MCP-1 also induced extracellular signal–regulated kinase, which, along with IL-6 release, was inhibited by pertussis toxin. PD98059 prevented MCP-1–induced extracellular signal–regulated kinase activation and cell proliferation. MCP-1 stimulated the binding activity of NF-κB and of activator protein-1 (AP-1). As demonstrated by cis element double-stranded (decoy) oligodeoxynucleotides, NF-κB was involved in IL-6 release by MCP-1, whereas proliferation was dependent on AP-1. The results clearly demonstrate that MCP-1 induces differential activation of NF-κB and AP-1 in VSMCs. Thus, our data propose a new mechanism for the proatherogenic effect of MCP-1.
    Keywords: Medicine;
    ISSN: 1079-5642
    E-ISSN: 15244636
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  • 6
    Language: English
    In: Molecular and cellular biochemistry, January 2003, Vol.242(1-2), pp.39-45
    Description: Smooth muscle cells (SMC) and endothelial cells (EC) play a pivotal role in arteriogenesis and atherosclerosis. We evaluated the role of EC on the growth of SMC and neonatal cardiomyocytes (NEO) by using serum-free EC-supernatant (AoCM). Five percent fetal calf serum was used in order to mimic growth effects of blood. EC and SMC purities were 99% as determined by absence or presence of markers such as CD31, desmin, alpha-smooth muscle actin and tropomyosin using immunostaining and FACS analysis. AoCM markedly influenced the morphology of NEO as determined by alpha-actinin staining but showed only little effect on the phenotype of SMC. Protein synthesis after 2 days increased 2.5-fold in SMC and 3.7-fold in NEO as determined by tritium incorporation. The values for serum (2.8 and 2.3-fold, respectively) were comparable. The induction of DNA-synthesis by serum in NEO was twice that of AoCM (3.9-fold). However, proliferative effects of serum and AoCM on SMC differed markedly: Serum induced a 66-fold increase in DNA-synthesis resulting in a 54% higher cell number. DNA-synthesis after AoCM treatment lead to a nonsignificant small increase and no proliferation was detected. Platelet derived growth factor (PDGF-AB), present in blood, induced a 47-fold increase in DNA-synthesis and a 38% increase in cell number. Our data suggest that EC in the absence of physical forces exert strong morphogenic effects on cardiomyocytes but they lack specific effects on smooth muscle cells. In vessels EC might function as a border to isolate SMC from key regulators in blood such as PDGFs.
    Keywords: Endothelium, Vascular -- Cytology ; Muscle, Smooth, Vascular -- Cytology ; Myocytes, Cardiac -- Cytology ; Myocytes, Smooth Muscle -- Cytology
    ISSN: 0300-8177
    E-ISSN: 15734919
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  • 7
    In: Anti-Cancer Drugs, 2000, Vol.11(5), pp.369-376
    Description: Bovine seminal ribonuclease (BS-RNase) is a protein with a number of biological effects. It shows antitumoral, aspermatogenic, antiembryonic, immunosuppressive and antiviral properties. The cytotoxic effects appear to be specific for tumor cells as non-malignant cells seem to be unaffected in vitro. Unfortunately, the in vivo application of BS-RNase so far was successful only when it was administered intratumorally. Therefore, the objective of the present investigation was to improve the properties of BS-RNase by attachment to nanoparticles made of polylactic acid (PLA-NP) using an adsorption method. This preparation was tested in vitro against leukemia (MOLT-4) and lymphoma (H9) cell lines sensitive and resistant to cytarabine. No difference between the nanoparticle preparation and pure BS-RNase was found in these tests. To examine the in vivo effects, the preparations were tested for their aspermatogenic and antiembryonal efficacy compared to the pure BS-RNase as a rapid test for antitumoral activity. The aspermatogenic and antiembryonal effects were enhanced by the nanoparticle preparation. Consequently, BS-RNase loaded adsorptively to PLA-NP holds promise for the in vivo use as an antitumoral agent. Further research will investigate the efficacy of this preparations in an in vivo tumor model.
    Keywords: Antineoplastic Agents -- Pharmacology ; Endoribonucleases -- Pharmacology ; Leukemia -- Drug Therapy ; Lymphoma -- Drug Therapy ; Tumor Cells, Cultured -- Drug Effects;
    ISSN: 0959-4973
    E-ISSN: 14735741
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