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1.
Crohns Colitis 360 ; 4(3): otac032, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36777428

RESUMO

Background: A Functional Medicine program was developed at an inflammatory bowel disease (IBD) center with the goal of integrating strategies to address modifiable lifestyle factors and to complete a 6-week elimination diet under the direction of a trained Functional Medicine dietitian and Functional Medicine providers. Methods: From January 2019 to November 2019, patients with controlled, but persistent, symptoms from IBD were offered enrollment. Each of the 5 visits incorporated an educational session focused on nutrition followed by a session focusing on modifiable lifestyle factors. The patients were placed on a supervised 6-week elimination diet. At each visit, patients completed the SIBDQ (Short Inflammatory Bowel Disease Questionnaire), FSS (Fatigue Severity Scale), PSQI (The Pittsburgh Sleep Quality Index), and MSQ (Medical Symptoms Questionnaire). Statistical analysis was performed using the Wilcoxon matched pairs signed-rank test. Results: Nineteen patients enrolled (2 men: 1 ulcerative colitis [UC], 1 Crohn's disease [CD]; 17 women: 3 UC, 14 CD). 15 patients completed all modules. There was improvement in all patient-reported outcomes (PROs) (FSS, P < .001; PSQI, P < .001; SIBDQ, P < .001; MSQ, P < .001). Every patient who completed the last session demonstrated weight loss. Conclusions: The psychoemotional roots to immune disease states, particularly IBD, are complicated and often not addressed in traditional care. We are just beginning to understand the impact of nutrition, sleep, stress, movement, and relationships on IBD. In this cohort, utilizing Functional Medicine as an adjunct to traditional care resulted in improvement in all PROs.

2.
Neurol Clin ; 38(4): 937-951, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33040870

RESUMO

The calcineurin inhibitors cyclosporine and tacrolimus are used for their immunosuppressive effects. Neurotoxic side effects include tremor, paresthesia, and headache. Rarer neurotoxicities include seizure, posterior reversible encephalopathy syndrome, and encephalopathy. Tacrolimus tends to be more neurotoxic than cyclosporine. Management of toxicities associated with calcineurin inhibitors includes dose reduction, switching between calcineurin inhibitors, or switching to a calcineurin-free regimen. Tumor necrosis factor (TNF) inhibitors are used in autoimmune diseases. Management of demyelinating conditions among patients treated with anti-TNF should follow standard of care and withdrawal of the anti-TNF. This drug class should be avoided in patients with a history of demyelinating conditions.


Assuntos
Inibidores de Calcineurina/efeitos adversos , Síndromes Neurotóxicas/etiologia , Inibidores do Fator de Necrose Tumoral/efeitos adversos , Humanos
3.
mBio ; 11(4)2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843554

RESUMO

Staphylococcus aureus is a common cause of bacteremia that can lead to severe complications once the bacteria exit the bloodstream and establish infection in secondary organs. Despite its clinical relevance, little is known about the bacterial factors facilitating the development of these metastatic infections. Here, we used an S. aureus transposon mutant library coupled to transposon insertion sequencing (Tn-Seq) to identify genes that are critical for efficient bacterial colonization of secondary organs in a murine model of metastatic bloodstream infection. Our transposon screen identified a LysR-type transcriptional regulator (LTTR), which was required for efficient colonization of secondary organs such as the kidneys in infected mice. The critical role of LTTR in secondary organ colonization was confirmed using an isogenic mutant deficient in the expression of LTTR. To identify the set of genes controlled by LTTR, we used an S. aureus strain carrying the LTTR gene in an inducible expression plasmid. Gene expression analysis upon induction of LTTR showed increased transcription of genes involved in branched-chain amino acid biosynthesis, a methionine sulfoxide reductase, and a copper transporter as well as decreased transcription of genes coding for urease and components of pyrimidine nucleotides. Furthermore, we show that transcription of LTTR is repressed by glucose, is induced under microaerobic conditions, and required trace amounts of copper ions. Our data thus pinpoints LTTR as an important element that enables a rapid adaptation of S. aureus to the changing host microenvironment.IMPORTANCEStaphylococcus aureus is an important pathogen that can disseminate via the bloodstream and establish metastatic infections in distant organs. To achieve a better understanding of the bacterial factors facilitating the development of these metastatic infections, we used in this study a Staphylococcus aureus transposon mutant library in a murine model of intravenous infection, where bacteria first colonize the liver as the primary infection site and subsequently progress to secondary sites such as the kidney and bones. We identified a novel LysR-type transcriptional regulator (LTTR), which was specifically required by S. aureus for efficient colonization of secondary organs. We also determined the transcriptional activation as well as the regulon of LTTR, which suggests that this regulator is involved in the metabolic adaptation of S. aureus to the host microenvironment found in secondary infection sites.


Assuntos
Bacteriemia/microbiologia , Proteínas de Bactérias/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade , Fatores de Transcrição/genética , Animais , Proteínas de Bactérias/metabolismo , Feminino , Regulação Bacteriana da Expressão Gênica , Camundongos , Camundongos Endogâmicos C57BL , Organismos Livres de Patógenos Específicos , Fatores de Transcrição/metabolismo , Transcrição Gênica , Virulência , Fatores de Virulência
4.
Rapid Commun Mass Spectrom ; 34(15): e8818, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32342561

RESUMO

RATIONALE: Acquisition quality in analytical science is key to obtaining optimal data from a sample. In very high-resolution mass spectrometry, quality is driven by the optimization of multiple parameters, including the use of scans and micro-scans (or transients) for performing a Fourier transformation. METHODS: Thirty-nine mass spectra of a single synthesized complex sample were acquired using various numbers of scans and micro-scans determined through a simple experimental design. An electrospray ionization source coupled with an LTQ Orbitrap XL™ mass spectrometer was used, and acquisition was performed using a single mass range. All the resulting spectra were treated in the same way to enable comparisons of assigned stoichiometric formulae between acquisitions. RESULTS: Converting the number of scans into micro-scans enhances signal quality by lowering noise and reducing artifacts. This modification also increases the number of attributed stoichiometric formulae for an equivalent acquisition time, giving access to a larger molecular diversity for the analyzed complex sample. CONCLUSIONS: For complex samples, the use of long acquisition times leads to optimal data quality, and the use of micro-scans instead of scans-only maximizes the number of attributed stoichiometric formulae.

5.
Rapid Commun Mass Spectrom ; 34(8): e8684, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31783433

RESUMO

RATIONALE: Quadrupole mass spectrometers equipped with an electron ionization (EI) sources have been widely used in space exploration to investigate the composition of planetary surfaces and atmospheres. However, the complexity of the samples and the minimal calibration for the fragmentation of molecules in the ionization chambers have prevented the deconvolution of the majority of the mass spectra obtained at different targets, thus limiting the determination of the exact composition of the samples analyzed. We propose a Monte-Carlo approach to solve this issue mathematically. METHODS: We decomposed simulated mass spectra of mixtures acquired with unit resolving power mass spectrometers and EI sources into the sum of the single components fragmentation patterns weighted by their relative concentration using interior-point least-square fitting. To fit compounds with poorly known fragmentation patterns, we used a Monte-Carlo method to vary the intensity of individual fragment ions. We then decomposed the spectrum thousands of times to obtain a statistical distribution. RESULTS: By performing the deconvolution on a mixture of seven different molecules with interfering fragmentation patterns (H2 O, O2 , CH4 , Ar, N2 , C2 H4 , and C2 H6 ) we show that this approach retrieves the mixing ratio of the individual components more accurately than regular mass spectra decomposition methods that rely on fragmentation patterns from general databases. It also provides the probability density function for each species's mixing ratio. CONCLUSIONS: By removing the solution degeneracy in the decomposition of mass spectra, the method described herein could significantly increase the scientific retrieval from archived space flight mass spectrometry data, where calibration of the ionization source is no longer an option.

6.
Perm J ; 232019.
Artigo em Inglês | MEDLINE | ID: mdl-31314736

RESUMO

The decline in cardiovascular disease mortality is stalling, and Million Hearts, a nationwide cardiovascular risk factor control campaign, is only halfway to its goal. In this commentary we identify 3 barriers beyond public reporting of performance that are hard stops for many Medical Groups that are participating in the Million Hearts initiative: 1) the inability of many physicians to access and visualize their patient panel electronic medical record data for patient and quality management, 2) a lack of compensation for the cost of team-based primary care, and 3) external support for single-condition registries rather than a single registry that contains the information that is necessary to manage all conditions of interest. These barriers have been overcome by high-performing Medical Groups and, if their innovations are adopted as standard practice by the US health care community, we believe that the Million Hearts goal can be achieved.


Assuntos
Doenças Cardiovasculares/prevenção & controle , Doenças Cardiovasculares/economia , Doenças Cardiovasculares/epidemiologia , Centers for Disease Control and Prevention, U.S. , Centers for Medicare and Medicaid Services, U.S. , Registros Eletrônicos de Saúde , Humanos , Equipe de Assistência ao Paciente/economia , Sistema de Registros , Estados Unidos/epidemiologia
7.
Biol Blood Marrow Transplant ; 23(9): 1473-1477, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28546074

RESUMO

Light chain amyloidosis (AL) results in tissue deposition of misfolded proteins, causing organ dysfunction. In an era of modern therapies, such as bortezomib, reassessment of the benefit of autologous hematopoietic cell transplantation (AHCT) should be considered. In this study, we compared outcomes between patients with AL receiving chemotherapy alone (CT) and those undergoing AHCT. Seventy-four patients with AL were analyzed retrospectively. Two cohorts of patients were studied, those receiving CT (n = 31) and those undergoing AHCT (n = 43). Of the 43 patients in the AHCT cohort, 29 received induction chemotherapy before AHCT, whereas 14 proceeded straight to AHCT without induction therapy. Compared with the CT cohort, patients in the AHCT cohort were younger and had higher ejection fractions, lower brain natriuretic peptide levels, and more severe proteinuria. The majority (87%) of patients in the CT cohort received bortezomib-based treatment. Transplantation-related mortality (TRM) was 7%. Patients receiving AHCT were more likely to achieve complete or very good partial response (P = .048). The median progression-free survival (PFS) and overall survival (OS) were superior in the AHCT cohort (not reached versus 9 months; P < .01 and 74 months versus 8 months; P = .03, respectively). Multivariable analysis demonstrated that improved PFS (hazard ratio, 3.86; 95% confidence interval [CI] 1.3 to 11.5; P = .02) and OS (hazard ratio, 5.6; 95% CI, 1.9 to 16; P < .001) were associated with use of AHCT compared with CT. Patients in the AHCT cohort had deeper and longer durations of response, with superior PFS and OS, compared with those in the CT cohort. Despite the limitations of this study, AHCT should be considered for eligible patients with AL at experienced transplantation centers that can offer this therapy with a low risk of TRM.


Assuntos
Antineoplásicos/uso terapêutico , Bortezomib/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/métodos , Amiloidose de Cadeia Leve de Imunoglobulina/terapia , Proteinúria/terapia , Adulto , Idoso , Feminino , Humanos , Amiloidose de Cadeia Leve de Imunoglobulina/imunologia , Amiloidose de Cadeia Leve de Imunoglobulina/mortalidade , Amiloidose de Cadeia Leve de Imunoglobulina/patologia , Quimioterapia de Indução/métodos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Peptídeo Natriurético Encefálico/sangue , Modelos de Riscos Proporcionais , Proteinúria/imunologia , Proteinúria/mortalidade , Proteinúria/patologia , Estudos Retrospectivos , Volume Sistólico/fisiologia , Transplante Autólogo , Resultado do Tratamento
8.
J Geophys Res Planets ; 121(9): 1814-1826, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29629249

RESUMO

We use observations from the Imaging Science Subsystem on Cassini to create maps of Saturn's Northern Hemisphere (NH) from 2008 to 2015, a time period including a seasonal transition (i.e., Spring Equinox in 2009) and the 2010 giant storm. The processed maps are used to investigate vortices in the NH during the period of 2008-2015. All recorded vortices have diameters (east-west) smaller than 6000 km except for the largest vortex that developed from the 2010 giant storm. The largest vortex decreased its diameter from ~11000 km in 2011 to ~5000 km in 2015, and its average diameter is ~6500 km during the period of 2011-2015. The largest vortex lasts at least 4 years, which is much longer than the lifetimes of most vortices (less than 1 year). The largest vortex drifts to north, which can be explained by the beta drift effect. The number of vortices displays varying behaviors in the meridional direction, in which the 2010 giant storm significantly affects the generation and development of vortices in the middle latitudes (25-45°N). In the higher latitudes (45-90°N), the number of vortices also displays strong temporal variations. The solar flux and the internal heat do not directly contribute to the vortex activities, leaving the temporal variations of vortices in the higher latitudes (45-90°N) unexplained.

9.
Pathogens ; 4(4): 722-38, 2015 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-26512700

RESUMO

The complement anaphylatoxin C5a contributes to host defense against Staphylococcus aureus. In this study, we investigated the functional role of the two known C5a receptors, C5aR1 and C5aR2, in the host response to S. aureus. We found that C5aR1(-/)(-) mice exhibited greater susceptibility to S. aureus bloodstream infection than wild type and C5aR2(-/)(-) mice, as demonstrated by the significantly higher bacterial loads in the kidneys and heart at 24 h of infection, and by the higher levels of inflammatory IL-6 in serum. Histological and immunohistochemistry investigation of infected kidneys at 24 h after bacterial inoculation revealed a discrete infiltration of neutrophils in wild type mice but already well-developed abscesses consisting of bacterial clusters surrounded by a large number of neutrophils in both C5aR1(-/)(-) and C5aR2(-/)(-) mice. Furthermore, blood neutrophils from C5aR1(-/)(-) mice were less efficient than those from wild type or C5aR2(-/)(-) mice at killing S. aureus. The requirement of C5aR1 for efficient killing of S. aureus was also demonstrated in human blood after disrupting C5a-C5aR1 signaling using specific inhibitors. These results demonstrated a role for C5aR1 in S. aureus clearance as well as a role for both C5aR1 and C5aR2 in the orchestration of the inflammatory response during infection.

10.
J Immunol ; 194(3): 1100-11, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25548227

RESUMO

Staphylococcus aureus can cause difficult-to-treat chronic infections. We recently reported that S. aureus chronic infection was associated with a profound inhibition of T cell responses. In this study, we investigated the mechanisms responsible for the suppression of T cell responses during chronic S. aureus infection. Using in vitro coculture systems, as well as in vivo adoptive transfer of CFSE-labeled OT-II cells, we demonstrated the presence of immunosuppressive mechanisms in splenocytes of S. aureus-infected mice that inhibited the response of OT-II cells to cognate antigenic stimulation. Immunosuppression was IL-10/TGF-ß independent but required cell-cell proximity. Using DEREG and Foxp3(gfp) mice, we demonstrated that CD4(+)CD25(+)Foxp3(+) regulatory T cells contributed, but only to a minor degree, to bystander immunosuppression. Neither regulatory B cells nor tolerogenic dendritic cells contributed to immunosuppression. Instead, we found a significant expansion of granulocytic (CD11b(+)Ly6G(+)Ly6C(low)) and monocytic (CD11b(+)Ly6G(-)Ly6C(high)) myeloid-derived suppressor cells (MDSC) in chronically infected mice, which exerted a strong immunosuppressive effect on T cell responses. Splenocytes of S. aureus-infected mice lost most of their suppressive activity after the in vivo depletion of MDSC by treatment with gemcitabine. Furthermore, a robust negative correlation was observed between the degree of T cell inhibition and the number of MDSC. An increase in the numbers of MDSC in S. aureus-infected mice by adoptive transfer caused a significant exacerbation of infection. In summary, our results indicate that expansion of MDSC and, to a minor degree, of regulatory T cells in S. aureus-infected mice may create an immunosuppressive environment that sustains chronic infection.


Assuntos
Imunomodulação , Células Mieloides/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Linfócitos B Reguladores/imunologia , Linfócitos B Reguladores/metabolismo , Comunicação Celular , Técnicas de Cocultura , Citocinas/biossíntese , Células Dendríticas/imunologia , Modelos Animais de Doenças , Feminino , Tolerância Imunológica/imunologia , Imunofenotipagem , Camundongos , Camundongos Transgênicos , Fenótipo , Índice de Gravidade de Doença , Baço/citologia , Baço/imunologia , Infecções Estafilocócicas/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/metabolismo
11.
mBio ; 5(6)2014 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-25538190

RESUMO

UNLABELLED: Osteomyelitis is a difficult-to-eradicate bone infection typically caused by Staphylococcus aureus. In this study, we investigated the in vivo transcriptional adaptation of S. aureus during bone infection. To this end, we determined the transcriptome of S. aureus during the acute (day 7) and chronic (day 28) phases of experimental murine osteomyelitis using RNA sequencing (RNA-Seq). We identified a total of 180 genes significantly more highly expressed by S. aureus during acute or chronic in vivo infection than under in vitro growth conditions. These genes encoded proteins involved in gluconeogenesis, proteolysis of host proteins, iron acquisition, evasion of host immune defenses, and stress responses. At the regulatory level, sarA and -R and saeR and -S as well as the small RNA RsaC were predominantly expressed by S. aureus during in vivo infection. Only nine genes, including the genes encoding the arginine deiminase (ADI) pathway and those involved in the stringent response, were significantly more highly expressed by S. aureus during the chronic than the acute stage of infection. Analysis by quantitative reverse transcription-PCR (qRT-PCR) of a subset of these in vivo-expressed genes in clinical specimens yielded the same results as those observed in the murine system. Collectively, our results show that during acute osteomyelitis, S. aureus induced the transcription of genes that mediate metabolic adaptation, immune evasion, and replication. During the chronic phase, however, S. aureus switched its transcriptional response from a proliferative to a persistence mode, probably driven by the severe deficiency in nutrient supplies. Interfering with the survival strategies of S. aureus during chronic infection could lead to more effective treatments. IMPORTANCE: The key to the survival success of pathogens during an infection is their capacity to rapidly adjust to the host environment and to evade the host defenses. Understanding how a pathogen redirects and fine-tunes its gene expression in response to the challenges of infection is central to the development of more efficient anti-infective therapies. Osteomyelitis is a debilitating infection of the bone predominantly caused by S. aureus. In this study, we evaluated the transcriptional response of S. aureus during bone infection. Our results indicate that S. aureus reprograms its genetic repertoire during the acute phase of infection to adapt to nutrient availability and to replicate within the host. During the chronic phase, S. aureus upregulates a survival genetic program activated in response to nutrient starvation. Thus, we have uncovered key survival pathways of S. aureus during acute and chronic osteomyelitis that can be used as therapeutic targets.


Assuntos
Perfilação da Expressão Gênica , Expressão Gênica , Osteomielite/microbiologia , Staphylococcus aureus/fisiologia , Estresse Fisiológico , Adaptação Fisiológica , Animais , Modelos Animais de Doenças , Camundongos , Reação em Cadeia da Polimerase em Tempo Real , Staphylococcus aureus/genética
12.
J Innate Immun ; 5(6): 581-90, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23571837

RESUMO

TREM-1 (triggering receptor expressed on myeloid cells) is a surface molecule expressed on neutrophils and macrophages which has been implicated in the amplification of inflammatory responses triggered during infection. In the present study, we have investigated the clinical significance of TREM-1 in Streptococcus pyogenes-induced severe sepsis in both experimentally infected mice as well as in patients with streptococcal toxic shock. We found that S. pyogenes induced a dose-dependent upregulation of TREM-1 in in vitro cultured phagocytic cells and in the organs of S. pyogenes-infected mice. Furthermore, we reported a positive correlation between serum levels of soluble TREM-1 (sTREM-1) and disease severity in infected patients as well as in experimentally infected mice. Hence, sTREM-1 may represent a useful surrogate marker for streptococcal sepsis. We found that modulation of TREM-1 by administration of the TREM-1 decoy receptor rTREM-1/Fc substantially attenuated the synthesis of inflammatory cytokines. More importantly, treatment of S. pyogenes-infected septic mice with rTREM-1/Fc or the synthetically produced conserved extracellular domain LP17 significantly improved disease outcome. In summary, our data suggest that TREM-1 may not only represent a valuable marker for S. pyogenes infection severity but it may also be an attractive target for the treatment of streptococcal sepsis.


Assuntos
Glicoproteínas de Membrana/imunologia , Receptores Imunológicos/imunologia , Sepse/imunologia , Infecções Estreptocócicas/imunologia , Streptococcus pyogenes/imunologia , Animais , Biomarcadores/sangue , Células Cultivadas , Feminino , Expressão Gênica/imunologia , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Humanos , Fragmentos Fc das Imunoglobulinas/genética , Fragmentos Fc das Imunoglobulinas/imunologia , Fragmentos Fc das Imunoglobulinas/metabolismo , Interleucina-6/imunologia , Interleucina-6/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/microbiologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Microscopia de Fluorescência , Prognóstico , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sepse/tratamento farmacológico , Sepse/microbiologia , Choque Séptico/sangue , Choque Séptico/imunologia , Choque Séptico/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/efeitos dos fármacos , Streptococcus pyogenes/fisiologia , Análise de Sobrevida , Receptor Gatilho 1 Expresso em Células Mieloides , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismo
13.
Am J Pathol ; 181(4): 1206-14, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22902429

RESUMO

Osteomyelitis is a serious bone infection typically caused by Staphylococcus aureus. The pathogenesis of osteomyelitis remains poorly understood, mainly for lack of experimental models that closely mimic human disease. We describe a novel murine model of metastatic chronic osteomyelitis initiated after intravenous inoculation of S. aureus microorganisms. The bacteria entered bones through the bloodstream and, after an acute phase with progressive growth (first 2 weeks after infection), they remained at constant numbers for up to 56 days (chronic phase). Clinical signs of illness and systemic inflammation were apparent only during the acute phase. Bone destruction and remodeling processes were readily detectable by magnetic resonance and X-ray imaging 3 weeks after infection, and high levels of bone deformation were observed during the chronic phase. Histological examination of infected bones demonstrated suppurative inflammation with foci of intense bacterial multiplication and necrosis during acute infection and osteoclastic resorption accompanied by new woven bone formation during chronic infection. Transmission electron microscopy revealed S. aureus microorganisms forming microcolonies within the nonmineralized collagen matrix or located intracellularly within neutrophils. In summary, our mouse model of staphylococcal hematogenous osteomyelitis precisely reproduces most features of the human disease. Although the extent of lesions in the chronic phase was subject to variation, this model is ideal for testing and monitoring novel treatment modalities via noninvasive imaging.


Assuntos
Osteomielite/microbiologia , Osteomielite/patologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/fisiologia , Animais , Fenômenos Biomecânicos , Doença Crônica , Modelos Animais de Doenças , Progressão da Doença , Feminino , Humanos , Úmero/diagnóstico por imagem , Úmero/microbiologia , Úmero/patologia , Imageamento Tridimensional , Inflamação/patologia , Imageamento por Ressonância Magnética , Camundongos , Camundongos Endogâmicos C57BL , Osteomielite/fisiopatologia , Radiografia , Infecções Estafilocócicas/fisiopatologia , Tíbia/diagnóstico por imagem , Tíbia/microbiologia , Tíbia/patologia , Tíbia/ultraestrutura , Fatores de Tempo
15.
PLoS One ; 6(11): e26974, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22073230

RESUMO

Production of reactive oxygen species represents a fundamental innate defense against microbes in a diversity of host organisms. Oxidative stress, amongst others, converts peptidyl and free methionine to a mixture of methionine-S- (Met-S-SO) and methionine-R-sulfoxides (Met-R-SO). To cope with such oxidative damage, methionine sulfoxide reductases MsrA and MsrB are known to reduce MetSOs, the former being specific for the S-form and the latter being specific for the R-form. However, at present the role of methionine sulfoxide reductases in the pathogenesis of intracellular bacterial pathogens has not been fully detailed. Here we show that deletion of msrA in the facultative intracellular pathogen Salmonella (S.) enterica serovar Typhimurium increased susceptibility to exogenous H(2)O(2), and reduced bacterial replication inside activated macrophages, and in mice. In contrast, a ΔmsrB mutant showed the wild type phenotype. Recombinant MsrA was active against free and peptidyl Met-S-SO, whereas recombinant MsrB was only weakly active and specific for peptidyl Met-R-SO. This raised the question of whether an additional Met-R-SO reductase could play a role in the oxidative stress response of S. Typhimurium. MsrC is a methionine sulfoxide reductase previously shown to be specific for free Met-R-SO in Escherichia (E.) coli. We tested a ΔmsrC single mutant and a ΔmsrBΔmsrC double mutant under various stress conditions, and found that MsrC is essential for survival of S. Typhimurium following exposure to H(2)O(2,) as well as for growth in macrophages, and in mice. Hence, this study demonstrates that all three methionine sulfoxide reductases, MsrA, MsrB and MsrC, facilitate growth of a canonical intracellular pathogen during infection. Interestingly MsrC is specific for the repair of free methionine sulfoxide, pointing to an important role of this pathway in the oxidative stress response of Salmonella Typhimurium.


Assuntos
Metionina Sulfóxido Redutases/metabolismo , Salmonella typhimurium/patogenicidade , Animais , Peróxido de Hidrogênio/metabolismo , Camundongos , Mutação , Salmonella typhimurium/enzimologia , Salmonella typhimurium/genética , Virulência
16.
J Bacteriol ; 192(11): 2929-32, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20304995

RESUMO

At present, Salmonella is considered to express two peroxiredoxin-type peroxidases, TsaA and AhpC. Here we describe an additional peroxiredoxin, Tpx, in Salmonella enterica and show that a single tpx mutant is susceptible to exogenous hydrogen peroxide (H(2)O(2)), that it has a reduced capacity to degrade H(2)O(2) compared to the ahpCF and tsaA mutants, and that its growth is affected in activated macrophages. These results suggest that Tpx contributes significantly to the sophisticated defense system that the pathogen has evolved to survive oxidative stress.


Assuntos
Proteínas de Bactérias/fisiologia , Peróxido de Hidrogênio/farmacologia , Peroxidases/fisiologia , Salmonella enterica/enzimologia , Salmonella enterica/crescimento & desenvolvimento , Animais , Proteínas de Bactérias/genética , Linhagem Celular , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/genética , Camundongos , Camundongos Endogâmicos BALB C , Peroxidases/genética , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética
17.
Microbiology (Reading) ; 155(Pt 4): 1332-1339, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19332834

RESUMO

Mycobacterium tuberculosis can utilize various nutrients including nitrate as a source of nitrogen. Assimilation of nitrate requires the reduction of nitrate via nitrite to ammonium, which is then incorporated into metabolic pathways. This study was undertaken to define the molecular mechanism of nitrate assimilation in M. tuberculosis. Homologues to a narGHJI-encoded nitrate reductase and a nirBD-encoded nitrite reductase have been found on the chromosome of M. tuberculosis. Previous studies have implied a role for NarGHJI in nitrate respiration rather than nitrate assimilation. Here, we show that a narG mutant of M. tuberculosis failed to grow on nitrate. A nirB mutant of M. tuberculosis failed to grow on both nitrate and nitrite. Mutant strains of Mycobacterium smegmatis mc(2)155 that are unable to grow on nitrate were isolated. The mutants were rescued by screening a cosmid library from M. tuberculosis, and a gene with homology to the response regulator gene glnR of Streptomyces coelicolor was identified. A DeltaglnR mutant of M. tuberculosis was generated, which also failed to grow on nitrate, but regained its ability to utilize nitrate when nirBD was expressed from a plasmid, suggesting a role of GlnR in regulating nirBD expression. A specific binding site for GlnR within the nirB promoter was identified and confirmed by electrophoretic mobility shift assay using purified recombinant GlnR. Semiquantitative reverse transcription PCR, as well as microarray analysis, demonstrated upregulation of nirBD expression in response to GlnR under nitrogen-limiting conditions. In summary, we conclude that NarGHJI and NirBD of M. tuberculosis mediate the assimilatory reduction of nitrate and nitrite, respectively, and that GlnR acts as a transcriptional activator of nirBD.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Mycobacterium tuberculosis/crescimento & desenvolvimento , Nitrato Redutase/metabolismo , Nitratos/metabolismo , Nitrito Redutases/metabolismo , Proteínas de Bactérias/genética , Meios de Cultura , Humanos , Dados de Sequência Molecular , Mutação , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Nitrato Redutase/genética , Nitrito Redutases/genética , Nitritos/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA
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