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1.
J Clin Invest ; 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31600168

RESUMO

Novel approaches for adjunctive therapy are urgently needed for complicated infections and patients with compromised immunity. Necrotizing fasciitis (NF) is a destructive skin and soft tissue infection. Despite treatment with systemic antibiotics and radical debridement of necrotic tissue, lethality remains high. The key iron regulatory hormone hepcidin was originally identified as a cationic antimicrobial peptide (AMP), but its putative expression and role in the skin, a major site of AMP production, have never been investigated. We report here that hepcidin production is induced in the skin of patients with group A Streptococcus (GAS) NF. In a GAS-induced NF model, mice lacking hepcidin in keratinocytes failed to restrict systemic spread of infection from an initial tissue focus. Unexpectedly, this effect was due to its ability to promote production of the CXCL1 chemokine by keratinocytes, resulting in neutrophil recruitment. Unlike CXCL1, hepcidin is resistant to degradation by major GAS proteases and could therefore serve as a reservoir to maintain steady-state levels of CXCL1 in infected tissue. Finally, injection of synthetic hepcidin at the site of infection can limit or completely prevent systemic spread of GAS infection, suggesting that hepcidin agonists could have a therapeutic role in NF.

2.
Acc Chem Res ; 52(4): 849-857, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30925037

RESUMO

Water security to protect human lives and support sustainable development is one of the greatest global challenges of this century. While a myriad of water pollutants can impact public health, the greatest threat arises from pathogenic bacteria that can be harbored in different components of water treatment, distribution, and reuse systems. Bacterial biofilms can also promote water infrastructure corrosion and biofouling, which substantially increase the cost and complexity of many critical operations. Conventional disinfection and microbial control approaches are often insufficient to keep up with the increasing complexity and renewed relevance of this pressing challenge. For example, common disinfectants cannot easily penetrate and eradicate biofilms, and are also relatively ineffective against resistant microorganisms. The use of chemical disinfectants is also curtailed by regulations aimed at minimizing the formation of harmful disinfection byproducts. Furthermore, disinfectants cannot be used to kill problematic bacteria in biological treatment processes without upsetting system performance. This underscores the need for novel, more precise, and more sustainable microbial control technologies. Bacteriophages (phages), which are viruses that exclusively infect bacteria, are the most abundant (and perhaps the most underutilized) biological resource on Earth, and hold great promise for targeting problematic bacteria. Although phages should not replace broad-spectrum disinfectants in drinking water treatment, they offer great potential for applications where selective targeting of problematic bacteria is warranted and antimicrobial chemicals are either relatively ineffective or their use would result in unintended detrimental consequences. Promising applications for phage-based biocontrol include selectively suppressing bulking and foaming bacteria that hinder activated sludge clarification, mitigating proliferation of antibiotic resistant strains in biological wastewater treatment systems where broad-spectrum antimicrobials would impair pollutant biodegradation, and complementing biofilm eradication efforts to delay corrosion and biofouling. Phages could also mitigate harmful cyanobacteria blooms that produce toxins in source waters, and could also serve as substitutes for the prophylactic use of antibiotics and biocides in animal agriculture to reduce their discharge to source waters and the associated selective pressure for resistant bacteria. Here, we consider the phage life cycle and its implications for bacterial control, and elaborate on the biochemical basis of such potential application niches in the water supply and reuse cycle. We also discuss potential technological barriers for phage-based bacterial control and suggest strategies and research needs to overcome them.

3.
Circulation ; 139(12): 1530-1547, 2019 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-30586758

RESUMO

BACKGROUND: Defective systemic and local iron metabolism correlates with cardiac disorders. Hepcidin, a master iron sensor, actively tunes iron trafficking. We hypothesized that hepcidin could play a key role to locally regulate cardiac homeostasis after acute myocardial infarction. METHODS: Cardiac repair was analyzed in mice harboring specific cardiomyocyte or myeloid cell deficiency of hepcidin and challenged with acute myocardial infarction. RESULTS: We found that the expression of hepcidin was elevated after acute myocardial infarction and the specific deletion of hepcidin in cardiomyocytes failed to improve cardiac repair and function. However, transplantation of bone marrow-derived cells from hepcidin-deficient mice ( Hamp-/-) or from mice with specific deletion of hepcidin in myeloid cells (LysMCRE/+/ Hampf/f) improved cardiac function. This effect was associated with a robust reduction in the infarct size and tissue fibrosis in addition to favoring cardiomyocyte renewal. Macrophages lacking hepcidin promoted cardiomyocyte proliferation in a prototypic model of apical resection-induced cardiac regeneration in neonatal mice. Interleukin (IL)-6 increased hepcidin levels in inflammatory macrophages. Hepcidin deficiency enhanced the number of CD45+/CD11b+/F4/80+/CD64+/MHCIILow/chemokine (C-C motif) receptor 2 (CCR2)+ inflammatory macrophages and fostered signal transducer and activator of transcription factor-3 (STAT3) phosphorylation, an instrumental step in the release of IL-4 and IL-13. The combined genetic suppression of hepcidin and IL-4/IL-13 in macrophages failed to improve cardiac function in both adult and neonatal injured hearts. CONCLUSIONS: Hepcidin refrains macrophage-induced cardiac repair and regeneration through modulation of IL-4/IL-13 pathways.

4.
Appl Environ Microbiol ; 84(18)2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-30006404

RESUMO

Bacterial endospores can serve as phage genome protection shells against various environmental stresses to enhance microbial control applications. The genomes of polyvalent lytic Bacillus phages PBSC1 and PBSC2, which infect both B. subtilis subsp. subtilis and B. cereus NRS 248, were incorporated into B. subtilis endospores (without integration into the host chromosome). When PBSC1 and PBSC2 were released from germinating endospores, they significantly inhibited the growth of the targeted opportunistic pathogen B. cereus Optimal endospore entrapment was achieved when phages were introduced to the fast-sporulating prespores at a multiplicity of infection of 1. Longer endospore maturation (48 h versus 24 h) increased both spore yield and efficiency of entrapment. Compared with free phages, spore-protected phage genomes showed significantly higher resistance toward high temperatures (60 to 80°C), extreme pH (pH 2 or pH 12), and copper ions (0.1 to 10 mg/liter). Endospore germination is inducible by low concentrations of l-alanine or by a germinant mixture (l-asparagine, d-glucose, d-fructose, and K+) to trigger the expression, assembly, and consequent release of phage particles within 60 to 90 min. Overall, the superior resiliency of polyvalent phages protected by endospores might enable nonrefrigerated phage storage and enhance phage applications after exposure to adverse environmental conditions.IMPORTANCE Bacteriophages are being considered for the control of multidrug-resistant and other problematic bacteria in environmental systems. However, the efficacy of phage-based microbial control is limited by infectivity loss during phage delivery and/or storage. Here, we exploit the pseudolysogenic state of phages, which involves incorporation of their genome into bacterial endospores (without integration into the host chromosome), to enhance survival in unfavorable environments. We isolated polyvalent (broad-host-range) phages that efficiently infect both benign and opportunistically pathogenic Bacillus strains and encapsulated the phage genomes in B. subtilis endospores to significantly improve resistance to various environmental stressors. Encapsulation by spores also significantly enhanced phage genome viability during storage. We also show that endospore germination can be induced on demand with nutrient germinants that trigger the release of active phages. Overall, we demonstrate that encapsulation of polyvalent phage genomes into benign endospores holds great promise for broadening the scope and efficacy of phage biocontrol.


Assuntos
Fagos Bacilares/genética , Bacillus cereus/virologia , Bacillus subtilis/virologia , Genoma Viral , Esporos Bacterianos/virologia , Fagos Bacilares/química , Fagos Bacilares/crescimento & desenvolvimento , Bacillus cereus/genética , Bacillus cereus/crescimento & desenvolvimento , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Temperatura Alta , Concentração de Íons de Hidrogênio , Esporos Bacterianos/química , Esporos Bacterianos/genética , Esporos Bacterianos/crescimento & desenvolvimento
5.
Appl Microbiol Biotechnol ; 102(7): 3375-3386, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29464325

RESUMO

Pseudonocardia spp. are receiving increasing attention due to their ability to biodegrade recalcitrant cyclic ether pollutants (e.g., 1,4-dioxane and tetrahydrofuran), as well as for their distinctive ecological niches (e.g., symbiosis with ants/plants and production of antibiotics). Isolating and characterizing Pseudonocardia spp. is thus important to discern their metabolic and physiological idiosyncrasies and advance their potential applications. However, slow growth, low cell yield, and dissimilar colony morphology hinder efficient isolation of Pseudonocardia using conventional plating methods. Here, we develop the first fluorescent probe (Pse631) targeting the 16S rRNA of Pseudonocardia members. In combination with flow cytometry and cell sorting, in situ hybridization with this probe enables sensitive and specific detection of Pseudonocardia cells in mixed cultures and enriched environmental samples without significant false positives, using Escherichia coli, Bacillus subtilis, and Mycobacterium spp. as negative controls. Pseudonocardia dioxanivorans CB1190 cells labeled with Pse631 as a positive control were detected when their relative abundance in the total bacterial community was as low as 0.1%. Effective separation of Pseudonocardia cells from the mixed consortium was confirmed by quantitative PCR analysis of sorted cells. This study provides a culture-independent high-throughput molecular approach enabling effective separation of Pseudonocardia populations from complex microbial communities. This approach will not only facilitate subsequent molecular analyses including species identification and quantification, but also advance understanding of their catabolic capacities and functional molecular diversity.


Assuntos
Actinomycetales/genética , Actinomycetales/isolamento & purificação , Citometria de Fluxo , Hibridização in Situ Fluorescente , Técnicas Microbiológicas/métodos , RNA Ribossômico 16S/genética , Sondas de Oligonucleotídeos/genética , Sondas de Oligonucleotídeos/metabolismo
6.
Microb Biotechnol ; 11(1): 189-198, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28984418

RESUMO

Two bacterial consortia were enriched from uncontaminated soil by virtue of their ability to grow on 1,4-dioxane (dioxane) as a sole carbon and energy source. Their specific dioxane degradation rates at 30°C, pH = 7 (i.e. 5.7 to 7.1 g-dioxane per g-protein per day) were comparable to those of two dioxane-metabolizing archetypes: Pseudonocardia dioxanivoransCB1190 and Mycobacterium dioxanotrophicusPH-06. Based on 16S rRNA sequencing, Mycobacterium was the dominant genus. Acetylene inhibition tests suggest that dioxane degradation was mediated by monooxygenases. However, qPCR analyses targeting the tetrahydrofuran/dioxane monooxygenase gene (thmA/dxmA) (which is, to date, the only sequenced dioxane monooxygenase gene) were negative, indicating that other (as yet unknown) catabolic gene(s) were responsible. DNA sequence analyses also showed threefold to sevenfold enrichment of group 5 and group 6 soluble di-iron monooxygenase (SDIMO) genes relative to the original soil samples. Whereas biodegradation of trace levels of dioxane is a common challenge at contaminated sites, both consortia degraded dioxane at low initial concentrations (300 µg l-1 ) below detectable levels (5 µg l-1 ) in bioaugmented microcosms prepared with impacted groundwater. Overall, this work shows that dioxane-degrading bacteria (and the associated natural attenuation potential) exist even in some uncontaminated soils, and may be enriched to broaden bioaugmentation options for sites experiencing insufficient dioxane catabolic capacity.


Assuntos
Bactérias/enzimologia , Dioxanos/metabolismo , Consórcios Microbianos , Oxigenases de Função Mista/metabolismo , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Biotransformação , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Concentração de Íons de Hidrogênio , Oxigenases de Função Mista/genética , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Temperatura Ambiente
7.
Front Physiol ; 8: 804, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29089902

RESUMO

Pulmonary iron excess is deleterious and contributes to a range of chronic and acute inflammatory diseases. Optimal lung iron concentration is maintained through dynamic regulation of iron transport and storage proteins. The iron-regulatory hormone hepcidin is also expressed in the lung. In order to better understand the interactions between iron-associated molecules and the hepcidin-ferroportin axis in lung iron balance, we examined lung physiology and inflammatory responses in two murine models of systemic iron-loading, either hepcidin knock-out (Hepc KO) or liver-specific hepcidin KO mice (Hepc KOliv), which do (Hepc KOliv) or do not (Hepc KO) express lung hepcidin. We have found that increased plasma iron in Hepc KO mice is associated with increased pulmonary iron levels, consistent with increased cellular iron uptake by pulmonary epithelial cells, together with an increase at the apical membrane of the cells of the iron exporter ferroportin, consistent with increased iron export in the alveoli. Subsequently, alveolar macrophages (AM) accumulate iron in a non-toxic form and this is associated with elevated production of ferritin. The accumulation of iron in the lung macrophages of hepcidin KO mice contrasts with splenic and hepatic macrophages which contain low iron levels as we have previously reported. Hepc KOliv mice with liver-specific hepcidin deficiency demonstrated same pulmonary iron overload profile as the Hepc KO mice, suggesting that pulmonary hepcidin is not critical in maintaining local iron homeostasis. In addition, the high iron load in the lung of Hepc KO mice does not appear to enhance acute lung inflammation or injury. Lastly, we have shown that intraperitoneal LPS injection is not associated with pulmonary hepcidin induction, despite high levels of inflammatory cytokines. However, intranasal LPS injection stimulates a hepcidin response, likely derived from AM, and alters pulmonary iron content in Hepc KO mice.

8.
Genome Announc ; 5(35)2017 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-28860235

RESUMO

We report here the complete genome sequence of Mycobacterium dioxanotrophicus PH-06, which is capable of using 1,4-dioxane as a sole source of carbon and energy. The reported sequence will enable the elucidation of this novel metabolic pathway and the development of molecular biomarkers to assess bioremediation potential at contaminated sites.

9.
J Am Soc Nephrol ; 28(12): 3605-3615, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28784700

RESUMO

Renal transplants remain a medical challenge, because the parameters governing allograft outcome are incompletely identified. Here, we investigated the role of serum iron in the sterile inflammation that follows kidney ischemia-reperfusion injury. In a retrospective cohort study of renal allograft recipients (n=169), increased baseline levels of serum ferritin reliably predicted a positive outcome for allografts, particularly in elderly patients. In mice, systemic iron overload protected against renal ischemia-reperfusion injury-associated sterile inflammation. Furthermore, chronic iron injection in mice prevented macrophage recruitment after inflammatory stimuli. Macrophages cultured in high-iron conditions had reduced responses to Toll-like receptor-2, -3, and -4 agonists, which associated with decreased reactive oxygen species production, increased nuclear localization of the NRF2 transcription factor, increased expression of the NRF2-related antioxidant response genes, and limited NF-κB and proinflammatory signaling. In macrophage-depleted animals, the infusion of macrophages cultured in high-iron conditions did not reconstitute AKI after ischemia-reperfusion, whereas macrophages cultured in physiologic iron conditions did. These findings identify serum iron as a critical protective factor in renal allograft outcome. Increasing serum iron levels in patients may thus improve prognosis of renal transplants.


Assuntos
Ferro/sangue , Rim/patologia , Traumatismo por Reperfusão/prevenção & controle , Adulto , Aloenxertos , Animais , Antioxidantes/metabolismo , Feminino , Ferritinas/sangue , Taxa de Filtração Glomerular , Humanos , Inflamação , Ferro/química , Rim/metabolismo , Transplante de Rim , Macrófagos/citologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Monócitos/citologia , Fator 2 Relacionado a NF-E2/metabolismo , Peritonite/metabolismo , Prognóstico , Espécies Reativas de Oxigênio/metabolismo , Traumatismo por Reperfusão/metabolismo , Transdução de Sinais
10.
Sci Rep ; 7(1): 2197, 2017 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-28526856

RESUMO

Oxidative stress causes significant increases in both cholesterol uptake and intracellular accumulation of the aging biomarker lipofuscin. Here we show that HPßCD addition mitigates these adverse effects in human fibroblasts by significantly reducing LDLr and SREBP1 gene expression. In the absence of oxidative stress, HPßCD addition induces a paradoxical response, increasing cholesterol accumulation (but not lipofuscin) via upregulation of cholesterol biosynthesis. These two distinct, but opposite effects highlight a previously overlooked therapeutic consideration: the cholesterol content of the treated cell determines which cholesterol pathways, either beneficial or harmful, are responsive to HPßCD.


Assuntos
2-Hidroxipropil-beta-Ciclodextrina/farmacologia , Colesterol/metabolismo , Lipofuscina/metabolismo , Redes e Vias Metabólicas , Fatores Etários , Apoptose , Linhagem Celular , Permeabilidade da Membrana Celular , Fibroblastos/metabolismo , Humanos , Lisossomos/metabolismo
11.
Environ Sci Technol ; 51(9): 5270-5278, 2017 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-28414441

RESUMO

Bacteriophages are widely recognized for their importance in microbial ecology and bacterial control. However, little is known about how phage polyvalence (i.e., broad host range) affects bacterial suppression and interspecies competition in environments harboring enteric pathogens and soil bacteria. Here we compare the efficacy of polyvalent phage PEf1 versus coliphage T4 in suppressing a model enteric bacterium (E. coli K-12) in mixtures with soil bacteria (Pseudomonas putida F1 and Bacillus subtilis 168). Although T4 was more effective than PEf1 in infecting E. coli K-12 in pure cultures, PEf1 was 20-fold more effective in suppressing E. coli under simulated multispecies biofilm conditions because polyvalence enhanced PEf1 propagation in P. putida. In contrast, soil bacteria do not propagate coliphages and hindered T4 diffusion through the biofilm. Similar tests were also conducted under planktonic conditions to discern how interspecies competition contributes to E. coli suppression without the confounding effects of restricted phage diffusion. Significant synergistic suppression was observed by the combined effects of phages plus competing bacteria. T4 was slightly more effective in suppressing E. coli in these planktonic mixed cultures, even though PEf1 reached higher concentrations by reproducing also in P. putida (7.2 ± 0.4 vs 6.0 ± 1.0 log10PFU/mL). Apparently, enhanced suppression by higher PEf1 propagation was offset by P. putida lysis, which decreased stress from interspecies competition relative to incubations with T4. In similar planktonic tests with more competing soil bacteria species, P. putida lysis was less critical in mitigating interspecies competition and PEf1 eliminated E. coli faster than T4 (36 vs 42 h). Overall, this study shows that polyvalent phages can propagate in soil bacteria and significantly enhance suppression of co-occurring enteric species.


Assuntos
Bacteriófagos , Enterobacteriaceae , Colífagos , Escherichia coli , Solo
12.
Water Res ; 112: 217-225, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28161562

RESUMO

A microcosm study was conducted to assess two biostimulation strategies (relative to natural attenuation) to bioremediate 1,4-dioxane contamination at a site in west Texas. Dioxane concentrations were relatively low (<300 µg/L), which represents a potential challenge to sustain and induce specific degraders. Thus, biostimulation was attempted with an auxiliary substrate known to induce dioxane-degrading monooxygenases (i.e., tetrahydrohyran [THF]) or with a non-inducing growth substrate (1-butanol [1-BuOH]). Amendment of 1-BuOH (100 mg/L) to microcosms that were not oxygen-limited temporarily enhanced dioxane biodegradation by the indigenous microorganisms. However, this stimulatory effect was not sustained by repeated amendments, which might be attributed to i) the inability of 1-BuOH to induce dioxane-degrading enzymes, ii) curing of catabolic plasmids, iii) metabolic flux dilution and catabolite repression, and iv) increased competition by commensal bacteria that do not degrade dioxane. Experiments with the archetype dioxane degrader Pseudonocardia dioxanivorans CB1190 repeatedly amended with 1-BuOH (500 mg/L added weekly for 4 weeks) corroborated the partial curing of catabolic plasmids (9.5 ± 7.4% was the plasmid retention ratio) and proliferation of derivative segregants that lost their ability to degrade dioxane. Addition of THF (300 µg/L) also had limited benefit due to competitive inhibition; significant dioxane degradation occurred only when the THF concentration decreased below approximately 160 µg/L. Overall, these results illustrate the importance of considering the possibility of unintentional hindrance of catabolism associated with the addition of auxiliary carbon sources to bioremediate aquifers impacted with trace concentrations of dioxane.


Assuntos
Actinomycetales/metabolismo , Biodegradação Ambiental , 1-Butanol , Bactérias , Água Subterrânea
13.
Environ Sci Technol ; 50(5): 2498-506, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26284736

RESUMO

Pyrolysis of contaminated soils at 420 °C converted recalcitrant heavy hydrocarbons into "char" (a carbonaceous material similar to petroleum coke) and enhanced soil fertility. Pyrolytic treatment reduced total petroleum hydrocarbons (TPH) to below regulatory standards (typically <1% by weight) within 3 h using only 40-60% of the energy required for incineration at 600-1200 °C. Formation of polycyclic aromatic hydrocarbons (PAHs) was not observed, with post-pyrolysis levels well below applicable standards. Plant growth studies showed a higher biomass production of Arabidopsis thaliana and Lactuca sativa (Simpson black-seeded lettuce) (80-900% heavier) in pyrolyzed soils than in contaminated or incinerated soils. Elemental analysis showed that pyrolyzed soils contained more carbon than incinerated soils (1.4-3.2% versus 0.3-0.4%). The stark color differences between pyrolyzed and incinerated soils suggest that the carbonaceous material produced via pyrolysis was dispersed in the form of a layer coating the soil particles. Overall, these results suggest that soil pyrolysis could be a viable thermal treatment to quickly remediate soils impacted by weathered oil while improving soil fertility, potentially enhancing revegetation.


Assuntos
Fertilizantes , Hidrocarbonetos/química , Poluentes do Solo/química , Solo/química , Arabidopsis/crescimento & desenvolvimento , Carbono , Hidrocarbonetos/análise , Incineração , Alface/crescimento & desenvolvimento , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Poluentes do Solo/análise , Tecnologia/métodos , Termogravimetria
14.
Appl Environ Microbiol ; 82(3): 808-15, 2016 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-26590277

RESUMO

Many studies on phage biology are based on isolation methods that may inadvertently select for narrow-host-range phages. Consequently, broad-host-range phages, whose ecological significance is largely unexplored, are consistently overlooked. To enhance research on such polyvalent phages, we developed two sequential multihost isolation methods and tested both culture-dependent and culture-independent phage libraries for broad infectivity. Lytic phages isolated from activated sludge were capable of interspecies or even interorder infectivity without a significant reduction in the efficiency of plating (0.45 to 1.15). Two polyvalent phages (PX1 of the Podoviridae family and PEf1 of the Siphoviridae family) were characterized in terms of adsorption rate (3.54 × 10(-10) to 8.53 × 10(-10) ml/min), latent time (40 to 55 min), and burst size (45 to 99 PFU/cell), using different hosts. These phages were enriched with a nonpathogenic host (Pseudomonas putida F1 or Escherichia coli K-12) and subsequently used to infect model problematic bacteria. By using a multiplicity of infection of 10 in bacterial challenge tests, >60% lethality was observed for Pseudomonas aeruginosa relative to uninfected controls. The corresponding lethality for Pseudomonas syringae was ∼ 50%. Overall, this work suggests that polyvalent phages may be readily isolated from the environment by using different sequential hosts, and this approach should facilitate the study of their ecological significance as well as enable novel applications.


Assuntos
Bacteriófagos/isolamento & purificação , Bacteriófagos/fisiologia , Especificidade de Hospedeiro , Esgotos/virologia , Cultura de Vírus/métodos , Bacteriófagos/classificação , Bacteriófagos/patogenicidade , DNA Viral , Escherichia coli K12/virologia , Podoviridae/isolamento & purificação , Podoviridae/fisiologia , Fagos de Pseudomonas/isolamento & purificação , Fagos de Pseudomonas/fisiologia , Pseudomonas aeruginosa/virologia , Pseudomonas putida/virologia , Pseudomonas syringae/virologia , Siphoviridae/isolamento & purificação , Siphoviridae/fisiologia
15.
Toxins (Basel) ; 7(8): 2918-58, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26248079

RESUMO

Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.


Assuntos
Autofagia/efeitos dos fármacos , Toxinas Bacterianas/farmacologia , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/metabolismo , Humanos
16.
J Immunol ; 194(7): 3389-99, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25750431

RESUMO

Besides their role in cellular responses to hypoxia, hypoxia-inducible factors (HIFs) are involved in innate immunity and also have anti-inflammatory (M2) functions, such as resolution of inflammation preceding healing. Whereas the first steps of the inflammatory response are associated with proinflammatory (M1) macrophages (MPs), resolution of inflammation is associated with anti-inflammatory MPs exhibiting an M2 phenotype. This M1 to M2 sequence is observed during postinjury muscle regeneration, which provides an excellent paradigm to study the resolution of sterile inflammation. In this study, using in vitro and in vivo approaches in murine models, we demonstrated that deletion of hif1a or hif2a in MPs has no impact on the acquisition of an M2 phenotype. Furthermore, using a multiscale methodological approach, we showed that muscles did not require macrophagic hif1a or hif2a to regenerate. These results indicate that macrophagic HIFs do not play a crucial role during skeletal muscle regeneration induced by sterile tissue damage.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Inflamação/genética , Inflamação/metabolismo , Músculo Esquelético/fisiologia , Células Mieloides/metabolismo , Regeneração , Animais , Animais Geneticamente Modificados , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Modelos Animais de Doenças , Técnicas de Inativação de Genes , Hipóxia/genética , Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Inflamação/diagnóstico , Inflamação/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Imagem por Ressonância Magnética , Masculino , Camundongos , Imagem Molecular , Músculo Esquelético/patologia , Fagocitose , Fenótipo
17.
Cell Metab ; 21(2): 311-323, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25651183

RESUMO

Mitochondrial iron accumulation is a hallmark of diseases associated with impaired iron-sulfur cluster (Fe-S) biogenesis, such as Friedreich ataxia linked to frataxin (FXN) deficiency. The pathophysiological relevance of the mitochondrial iron loading and the underlying mechanisms are unknown. Using a mouse model of hepatic FXN deficiency in combination with mice deficient for iron regulatory protein 1 (IRP1), a key regulator of cellular iron metabolism, we show that IRP1 activation in conditions of Fe-S deficiency increases the available cytosolic labile iron pool. Surprisingly, our data indicate that IRP1 activation sustains mitochondrial iron supply and function rather than driving detrimental iron overload. Mitochondrial iron accumulation is shown to depend on mitochondrial dysfunction and heme-dependent upregulation of the mitochondrial iron importer mitoferrin-2. Our results uncover an unexpected protective role of IRP1 in pathological conditions associated with altered Fe-S metabolism.


Assuntos
Proteína 1 Reguladora do Ferro/metabolismo , Proteínas de Ligação ao Ferro/genética , Proteínas de Ligação ao Ferro/metabolismo , Ferro/metabolismo , Mitocôndrias/metabolismo , Animais , Ataxia de Friedreich/genética , Ataxia de Friedreich/metabolismo , Ataxia de Friedreich/patologia , Proteína 1 Reguladora do Ferro/deficiência , Proteína 1 Reguladora do Ferro/genética , Proteínas com Ferro-Enxofre/deficiência , Proteínas com Ferro-Enxofre/metabolismo , Fígado/metabolismo , Fígado/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
18.
J Acquir Immune Defic Syndr ; 68 Suppl 2: S221-31, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25723988

RESUMO

BACKGROUND: Female sex workers (FSW) in Mali are highly vulnerable to HIV. Their prevalence in 2009 was 9 times higher (24.2%) than that among pregnant women (2.7%). METHODS: Four Integrated HIV/sexually transmitted infection (STI) Surveillance and Behavioral Surveys among FSW in Mali (2000, 2003, 2006, and 2009) tracked demographic characteristics, behavior, and HIV and STI prevalence. Logistic regression using generalized estimating equations to control for the cluster effect identified factors associated with HIV-positive serostatus adjusting for potential confounding. RESULTS: Of 2430 FSW, 40.8% were Nigerian, 36.8% were Malian, and 22.4% were from other neighboring countries. Between 2003 and 2009, HIV prevalence dropped from 44.14% to 28.49% (P < 0.0001) among Malians, from 21.33% to 12.71% (P = 0.0082) among Nigerians, and from 43.42% to 33.67% (P = 0.0442) among "others." Between 2000 and 2009, condom availability increased (89.18%-99.3%; P < 0.0001) as did HIV testing (40%-75%; P < 0.0001). Consistent condom use with clients improved for Malians (72.3%-81.5%; P = 0.0092), but not among Nigerians (92.7%-90.94%; P = 0.8240) and "others" (88.9%-88.48%; P = 0.8452). Consistent condom use with boyfriends was low and improved only for Nigerians (9.8%-28.4%; P = 0.0003). Factors associated with HIV prevalence in the multivariate model were older age, study year (2003 and 2006), nationality, lack of education, mobility, STI symptoms, gonorrhea prevalence, and younger age at first sex. CONCLUSIONS: This study documents progress in the fight against HIV among FSW in Mali. The different vulnerabilities to HIV found for different nationality FSW should be considered in programming and future research.


Assuntos
Infecções por HIV/prevenção & controle , Adulto , Preservativos , Emigrantes e Imigrantes , Feminino , Infecções por HIV/epidemiologia , Comportamentos Relacionados com a Saúde , Humanos , Mali/epidemiologia , Prevalência , Fatores de Risco , Sexo sem Proteção , Adulto Jovem
19.
J Immunol ; 194(7): 3259-66, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25710915

RESUMO

Helicobacter pylori infection triggers chronic inflammation of the gastric mucosa that may progress to gastric cancer. The hypoxia-inducible factors (HIFs) are the central mediators of cellular adaptation to low oxygen levels (hypoxia), but they have emerged recently as major transcriptional regulators of immunity and inflammation. No studies have investigated whether H. pylori affects HIF signaling in immune cells and a potential role for HIF in H. pylori-mediated gastritis. HIF-1 and HIF-2 expression was examined in human H. pylori-positive gastritis biopsies. Subsequent experiments were performed in naive and polarized bone marrow-derived macrophages from wild-type (WT) and myeloid HIF-1α-null mice (HIF-1(Δmyel)). WT and HIF-1(Δmyel) mice were inoculated with H. pylori by oral gavage and sacrificed 6 mo postinfection. HIF-1 was specifically expressed in macrophages of human H. pylori-positive gastritis biopsies. Macrophage HIF-1 strongly contributed to the induction of proinflammatory genes (IL-6, IL-1ß) and inducible NO synthase in response to H. pylori. HIF-2 expression and markers of M2 macrophage differentiation were decreased in response to H. pylori. HIF-1(Δmyel) mice inoculated with H. pylori for 6 mo presented with a similar bacterial colonization than WT mice but, surprisingly, a global increase of inflammation, leading to a worsening of the gastritis, measured by an increased epithelial cell proliferation. In conclusion, myeloid HIF-1 is protective in H. pylori-mediated gastritis, pointing to the complex counterbalancing roles of innate immune and inflammatory phenotypes in driving this pathology.


Assuntos
Gastrite/etiologia , Gastrite/metabolismo , Infecções por Helicobacter/complicações , Infecções por Helicobacter/metabolismo , Helicobacter pylori , Fator 1 Induzível por Hipóxia/metabolismo , Células Mieloides/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Biópsia , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Mucosa Gástrica/imunologia , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Gastrite/patologia , Infecções por Helicobacter/genética , Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Humanos , Mediadores da Inflamação/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos , Camundongos Transgênicos , Células Mieloides/imunologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/microbiologia
20.
World J Urol ; 33(2): 281-7, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24748552

RESUMO

OBJECTIVE: To evaluate the expression of CXCR4, its ligand SDF-1, ß-catenin and E-cadherin throughout the local tumor microenvironment of prostate cancer. PATIENTS AND METHODS: A total of 64 prostate cancer specimens, 24 frozen and 40 paraffin-embedded sections, were obtained from patients treated with radical prostatectomy for clinically localized cancer. Real-time RT-PCR was used for mRNA quantification of CXCR4 and SDF-1 in the tumor center (T), tumor front (F) and distant peritumoral tissue (D). Immunohistochemical analysis was used to investigate the expression patterns of CXCR4, E-cadherin and ß-catenin. Clinical records of these patients were studied for follow-up data, and the prognostic value of these molecules' expression was statistically assessed. RESULTS: CXCR4 mRNA and protein were significantly increased at the tumor front as compared to distant tissue or tumor center. In comparison, SDF-1 mRNA level gradually increased from the tumor center to the distant peritumoral tissue. High CXCR4 at the tumor front was associated with high Gleason score. Low SDF-1 at the tumor front was associated with locally advanced cancer and disease recurrence. Moreover, high CXCR4 staining at the tumor front and increased cytosolic E-cadherin expression in the same location was associated with locally advanced disease. CONCLUSIONS: CXCR4 seems overexpressed at the tumor front of prostate tumors, where it potentially promotes cell migration toward the SDF-1 centrifugal attracting gradient, as well as epithelial-mesenchymal transition. High CXCR4 and low SDF-1 levels at tumor front were both associated with adverse histological features.


Assuntos
Biomarcadores Tumorais/biossíntese , Caderinas/biossíntese , Quimiocina CXCL12/biossíntese , Neoplasias da Próstata/metabolismo , Receptores CXCR4/biossíntese , beta Catenina/biossíntese , Idoso , Movimento Celular , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Prostatectomia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/cirurgia , RNA Mensageiro/biossíntese
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