Lung damage in mice after inhalation of nanofilm spray products: The role of perfluorination and free hydroxyl groups. Nørgaard AW, Larsen ST, Hammer M, Poulsen SS, Jensen KA, Nielsen GD, Wolkoff P Toxicol Sci
2010
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Exposures to two commercial nanofilm spray products (NFPs), a floor sealant (NFP 1) and a coating product for tiles (NFP 2), were investigated for airway irritation, airway inflammation and lung damage in a mouse inhalation model. The particle-exposure was characterized by particle number, particle size-distribution and gravimetric analysis. BALB/cJ mice were exposed for 60 min to the aerosolized products at 3.3-60 mg/m(3) (10(5) - 10(6) fine particles/cm(3)) measured in the breathing zone of the mice. Lung inflammation and lung damage were assessed by study of bronchoalveolar lavage fluid (BALF) cytology, protein in BALF and histology. Mass spectral analysis showed that NFP 1 and NFP 2 contained hydrolysates and condensates of a perfluorosilane and alkylsilane, respectively. NFP 1 induced a concentration-dependent decrease of the tidal volume lasting for at least one day. Exposure concentrations above 16.1 mg/m(3) (2.5x10(6) fine particles/cm(3)) gave rise to significant increases of protein level in BALF, reduced body weight, and histological examination showed atelectasis, emphysema and hemorrhages. A narrow interval between the no-effect level (16.1 mg/m(3)) and lethal concentrations (18.4 mg/m(3)) was observed. The alkylsilane based product (NFP 2) had no effect at the concentrations studied. Experiments with different types of perfluorinated silanes and siloxanes showed that the toxic effects did not arise solely from the perfluorination. The number of free hydroxyl groups in the silanes/siloxanes was also critical for the toxicity. | 20348230
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Impairment of PGC-1alpha expression, Neuropathology and Hepatic Steatosis in a transgenic mouse model of Huntington's disease following chronic energy deprivation. Chaturvedi RK, Calingasan NY, Yang L, Hennessey T, Johri A, Beal MF Hum Mol Genet
2010
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We investigated the ability of AMP-activated protein kinase (AMPK) to activate PPARgamma coactivator-1alpha (PGC-1alpha) in the brain, liver and brown adipose tissue (BAT) of the NLS-N171-82Q transgenic mouse model of Huntington's Disease (HD). In the striatum of the HD mice, the baseline levels of PGC-1alpha, NRF1, NRF2, Tfam, COX-II, PPARdelta, CREB and ERRalpha mRNA, and mitochondrial DNA (mtDNA), were significantly reduced. Administration of the creatine analog beta guanidinopropionic acid (GPA), reduced ATP and PCr levels, and increased AMPK mRNA in both the cerebral cortex and striatum. Treatment with GPA significantly increased expression of PGC-1alpha, NRF1, Tfam, and downstream genes in the striatum and cerebral cortex of wildtype (WT) mice, but there was no effect on these genes in the HD mice. The striatum of the untreated HD mice showed microvacuolation in the neuropil, as well as gliosis and huntingtin aggregates, which were exacerbated by treatment with GPA. GPA treatment produced a significant increase in mtDNA in the cerebral cortex and striatum of WT mice, but not in HD mice. The HD mice treated with GPA had impaired activation of liver PGC-1alpha, and developed hepatic steatosis with accumulation of lipids, degeneration of hepatocytes, and impaired activation of gluconeogenesis. The BAT in the HD mice showed vacuolation due to accumulation of neutral lipids, and age-dependent impairment of UCP-1 activation and temperature regulation. Impaired activation of PGC-1alpha, therefore plays an important role in the behavioral phenotype, metabolic disturbances, and pathology of HD, which suggests the possibility that agents which enhance PGC-1alpha function, will exert therapeutic benefits in HD patients. | 20529956
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Custom-designed MLPA using multiple short synthetic probes: application to methylation analysis of five promoter CpG islands in tumor and urine specimens from patients with bladder cancer. Serizawa RR, Ralfkiaer U, Dahl C, Lam GW, Hansen AB, Steven K, Horn T, Guldberg P J Mol Diagn
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402-8. Epub 2010 Apr 22.
2010
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Ligation of two oligonucleotide probes hybridized adjacently to a DNA template has been widely used for detection of genome alterations. The multiplex ligation-dependent probe amplification (MLPA) technique allows simultaneous screening of multiple target sequences in a single reaction by using pairs of probes that carry tails for binding of common amplification primers. Resolution of the various targets is achieved by electrophoresis on the basis of predefined differences in amplicon length. In the conventional MLPA approach, one of the two target probes is generated by cloning in a single-stranded bacteriophage vector to introduce a sequence of defined length between the primer binding site and the specific target sequence. Here we demonstrate that differences in amplicon length can be achieved by using multiple short synthetic probes for each target sequence. When joined by a DNA ligase, these probes will form a single amplifiable template whose length is defined by the number and lengths of the individual probes. We have used this principle to establish a methylation-specific MLPA (MS-MLPA) assay that simultaneously determines the methylation status of five promoter CpG islands, and we have used this assay to analyze DNA from tumor tissue and corresponding urine samples from patients with bladder cancer. Our data show that the use of multiple short synthetic probes provides a simple means for custom-designed MS-MLPA analysis. Full Text Article | 20413679
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Genome-wide analysis of DNA binding and transcriptional regulation by the mammalian Doublesex homolog DMRT1 in the juvenile testis. Murphy MW, Sarver AL, Rice D, Hatzi K, Ye K, Melnick A, Heckert LL, Zarkower D, Bardwell VJ Proc Natl Acad Sci U S A
2010
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The DM domain proteins Doublesex- and MAB-3-related transcription factors (DMRTs) are widely conserved in metazoan sex determination and sexual differentiation. One of these proteins, DMRT1, plays diverse and essential roles in development of the vertebrate testis. In mammals DMRT1 is expressed and required in both germ cells and their supporting Sertoli cells. Despite its critical role in testicular development, little is known about how DMRT1 functions as a transcription factor or what genes it binds and regulates. We combined ChIP methods with conditional gene targeting and mRNA expression analysis and identified almost 1,400 promoter-proximal regions bound by DMRT1 in the juvenile mouse testis and determined how expression of the associated mRNAs is affected when Dmrt1 is selectively mutated in germ cells or Sertoli cells. These analyses revealed that DMRT1 is a bifunctional transcriptional regulator, activating some genes and repressing others. ChIP analysis using conditional mutant testes showed that DNA binding and transcriptional regulation of individual target genes can differ between germ cells and Sertoli cells. Genes bound by DMRT1 in vivo were enriched for a motif closely resembling the sequence DMRT1 prefers in vitro. Differential response of genes to loss of DMRT1 corresponded to differences in the enriched motif, suggesting that other transacting factors may modulate DMRT1 activity. DMRT1 bound its own promoter and those of six other Dmrt genes, indicating auto- and cross-regulation of these genes. Many of the DMRT1 target genes identified here are known to be important for a variety of functions in testicular development; the others are candidates for further investigation. | 20616082
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Exposure to bioaerosols during the growth season in an organic greenhouse tomato production using Supresivit(R) (Trichoderma harzianum) and Mycostop(R) (Streptomyces griseoviridis). Hansen VM, Winding A, Madsen AM Appl Environ Microbiol
2010
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In working environments, especially in confined spaces like greenhouses, elevated concentrations of airborne microorganisms may become a problem for workers' health. Additionally, the use of microbial pest control agents may increase exposure to microorganisms. The aim of this study was to investigate tomato growers' exposure to naturally occurring bioaerosol components (dust, bacteria, fungi, actinomycetes, (1-->3)-beta-D-glucans and endotoxin) and microbial pest control agents applied by drip irrigation. Airborne dust was collected with filter samplers and analyzed for microorganisms by plate counts and total counts in microscope. Analysis of (1-->3)-beta-D-glucan and endotoxin content were performed by kinetic, chromatic Limulus Amoebocyte Lysate tests. The fungal strain (Trichoderma harzianum) from the biocontrol product Supresivit(R) was identified by PCR analysis. Measurements were performed on the day of drip irrigation and one week, one month and three months after the irrigation. T. harzianum from Supresivit(R) could only be detected on the day of treatment. Streptomyces griseoviridis, an applied microbial pest control agent, was not detected in the air during this investigation. We found that bioaerosol exposure increases during the growth season and that exposure to fungi, bacteria, and endotoxin can reach levels during the harvest period, that may cause respiratory symptoms in growers. The collected data indicates that MPCAs applied by drip irrigation do not become airborne later in the season. | 20622135
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Tarp regulates early Chlamydia-induced host cell survival through interactions with the human adaptor protein SHC1. Mehlitz A, Banhart S, Mäurer AP, Kaushansky A, Gordus AG, Zielecki J, Macbeath G, Meyer TF J Cell Biol
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143-57.
2010
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Many bacterial pathogens translocate effector proteins into host cells to manipulate host cell functions. Here, we used a protein microarray comprising virtually all human SRC homology 2 (SH2) and phosphotyrosine binding domains to comprehensively and quantitatively assess interactions between host cell proteins and the early phase Chlamydia trachomatis effector protein translocated actin-recruiting phosphoprotein (Tarp), which is rapidly tyrosine phosphorylated upon host cell entry. We discovered numerous novel interactions between human SH2 domains and phosphopeptides derived from Tarp. The adaptor protein SHC1 was among Tarp's strongest interaction partners. Transcriptome analysis of SHC1-dependent gene regulation during infection indicated that SHC1 regulates apoptosis- and growth-related genes. SHC1 knockdown sensitized infected host cells to tumor necrosis factor-induced apoptosis. Collectively, our findings reveal a critical role for SHC1 in early C. trachomatis-induced cell survival and suggest that Tarp functions as a multivalent phosphorylation-dependent signaling hub that is important during the early phase of chlamydial infection. | 20624904
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Antibody-directed myostatin inhibition in 21-mo-old mice reveals novel roles for myostatin signaling in skeletal muscle structure and function. Murphy KT, Koopman R, Naim T, Léger B, Trieu J, Ibebunjo C, Lynch GS FASEB J
2010
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Sarcopenia is the progressive loss of skeletal muscle mass and function with advancing age, leading to reduced mobility and quality of life. We tested the hypothesis that antibody-directed myostatin inhibition would attenuate the decline in mass and function of muscles of aged mice and that apoptosis would be reduced. Eighteen-month-old C57BL/6 mice were treated for 14 wk with a once-weekly injection of saline (control, n=9) or a mouse chimera of anti-human myostatin antibody (PF-354, 10 mg/kg; n=12). PF-354 prevented the age-related reduction in body mass and increased soleus, gastrocnemius, and quadriceps muscle mass (P<0.05). PF-354 increased fiber cross-sectional area by 12% and enhanced maximum in situ force of tibialis anterior (TA) muscles by 35% (P<0.05). PF-354 increased the proportion of type IIa fibers by 114% (P<0.01) and enhanced activity of oxidative enzymes (SDH) by 39% (P<0.01). PF-354 reduced markers of apoptosis in TA muscle cross-sections by 56% (P<0.03) and reduced caspase3 mRNA by 65% (P<0.04). Antibody-directed myostatin inhibition attenuated the decline in mass and function of muscles of aging mice, in part, by reducing apoptosis. These observations identify novel roles for myostatin in regulation of muscle mass and highlight the therapeutic potential of antibody-directed myostatin inhibition for sarcopenia.-Murphy, K. T., Koopman, R., Naim, T., Léger, B., Trieu, J., Ibebunjo, C. Lynch, G. S. Antibody-directed myostatin inhibition in 21-mo-old mice reveals novel roles for myostatin signaling in skeletal muscle structure and function. | 20624929
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DNA polymerase theta up-regulation is associated with poor survival in breast cancer, perturbs DNA replication, and promotes genetic instability. Lemée F, Bergoglio V, Fernandez-Vidal A, Machado-Silva A, Pillaire MJ, Bieth A, Gentil C, Baker L, Martin AL, Leduc C, Lam E, Magdeleine E, Filleron T, Oumouhou N, Kaina B, Seki M, Grimal F, Lacroix-Triki M, Thompson A, Roché H, Bourdon JC, Wood RD, Hoffmann JS, Cazaux C Proc Natl Acad Sci U S A
107
13390-5. Epub 2010 Jul 12.
2010
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"Replicative stress" is one of the main factors underlying neoplasia from its early stages. Genes involved in DNA synthesis may therefore represent an underexplored source of potential prognostic markers for cancer. To this aim, we generated gene expression profiles from two independent cohorts (France, n=206; United Kingdom, n=117) of patients with previously untreated primary breast cancers. We report here that among the 13 human nuclear DNA polymerase genes, DNA Polymerase (POLQ) is the only one significantly up-regulated in breast cancer compared with normal breast tissues. Importantly, POLQ up-regulation significantly correlates with poor clinical outcome (4.3-fold increased risk of death in patients with high POLQ expression), and this correlation is independent of Cyclin E expression or the number of positive nodes, which are currently considered as markers for poor outcome. POLQ expression provides thus an additional indicator for the survival outcome of patients with high Cyclin E tumor expression or high number of positive lymph nodes. Furthermore, to decipher the molecular consequences of POLQ up-regulation in breast cancer, we generated human MRC5-SV cell lines that stably overexpress POLQ. Strong POLQ expression was directly associated with defective DNA replication fork progression and chromosomal damage. Therefore, POLQ overexpression may be a promising genetic instability and prognostic marker for breast cancer. Full Text Article | 20624954
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MicroRNA-10a regulation of proinflammatory phenotype in athero-susceptible endothelium in vivo and in vitro. Fang Y, Shi C, Manduchi E, Civelek M, Davies PF Proc Natl Acad Sci U S A
2010
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A chronic proinflammatory state precedes pathological change in arterial endothelial cells located within regions of susceptibility to atherosclerosis. The potential contributions of regulatory microRNAs to this disequilibrium were investigated by artery site-specific profiling in normal adult swine. Expression of endothelial microRNA10a (miR-10a) was lower in the athero-susceptible regions of the inner aortic arch and aorto-renal branches than elsewhere. Expression of Homeobox A1 (HOXA1), a known miR-10a target, was up-regulated in the same locations. Endothelial transcriptome microarray analysis of miR-10a knockdown in cultured human aortic endothelial cells (HAEC) identified IkappaB/NF-kappaB-mediated inflammation as the top category of up-regulated biological processes. Phosphorylation of IkappaBalpha, a prerequisite for IkappaBalpha proteolysis and NF-kappaB activation, was significantly up-regulated in miR-10a knockdown HAEC and was accompanied by increased nuclear expression of NF-kappaB p65. The inflammatory biomarkers monocyte chemotactic protein 1 (MCP-1), IL-6, IL-8, vascular cell adhesion molecule 1 (VCAM-1), and E-selectin were elevated following miR-10a knockdown. Conversely, knockin of miR-10a (a conservative 25-fold increase) inhibited the basal expression of VCAM-1 and E-selectin in HAEC. Two key regulators of IkappaBalpha degradation-mitogen-activated kinase kinase kinase 7 (MAP3K7; TAK1) and beta-transducin repeat-containing gene (betaTRC)-contain a highly conserved miR-10a binding site in the 3' UTR. Both molecules were up-regulated by miR-10a knockdown and suppressed by miR-10a knockin, and evidence of direct miR-10a binding to the 3' UTR was demonstrated by luciferase assay. Comparative expression studies of endothelium located in athero-susceptible aortic arch and athero-protected descending thoracic aorta identified significantly up-regulated MAP3K7, betaTRC, phopho-IkappaBalpha, and nuclear p65 expression suggesting that the differential expression of miR-10a contributes to the regulation of proinflammatory endothelial phenotypes in athero-susceptible regions in vivo. | 20624982
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Sucrose nonfermenting AMPK-related kinase (SNARK) mediates contraction-stimulated glucose transport in mouse skeletal muscle. Koh HJ, Toyoda T, Fujii N, Jung MM, Rathod A, Middelbeek RJ, Lessard SJ, Treebak JT, Tsuchihara K, Esumi H, Richter EA, Wojtaszewski JF, Hirshman MF, Goodyear LJ Proc Natl Acad Sci U S A
2010
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The signaling mechanisms that mediate the important effects of contraction to increase glucose transport in skeletal muscle are not well understood, but are known to occur through an insulin-independent mechanism. Muscle-specific knockout of LKB1, an upstream kinase for AMPK and AMPK-related protein kinases, significantly inhibited contraction-stimulated glucose transport. This finding, in conjunction with previous studies of ablated AMPKalpha2 activity showing no effect on contraction-stimulated glucose transport, suggests that one or more AMPK-related protein kinases are important for this process. Muscle contraction increased sucrose nonfermenting AMPK-related kinase (SNARK) activity, an effect blunted in the muscle-specific LKB1 knockout mice. Expression of a mutant SNARK in mouse tibialis anterior muscle impaired contraction-stimulated, but not insulin-stimulated, glucose transport. Whole-body SNARK heterozygotic knockout mice also had impaired contraction-stimulated glucose transport in skeletal muscle, and knockdown of SNARK in C2C12 muscle cells impaired sorbitol-stimulated glucose transport. SNARK is activated by muscle contraction and is a unique mediator of contraction-stimulated glucose transport in skeletal muscle. | 20713714
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