RESUMO
Enteroinvasive Escherichia coli (EIEC) is a diarrheagenic E. coli pathotype carrying a virulence plasmid that encodes a type III secretion system (TTSS) directly implicated in bacterial cell invasion. Since 2012, EIEC serotype O96:H19 has been recognized in Europe, Colombia, and most recently Uruguay. In addition to the invasion phenotype, the strains isolated from Colombian children with moderate-to-severe gastroenteritis had a strong biofilm formation phenotype, and as a result, they are referred to as biofilm-forming enteroinvasive E. coli (BF-EIEC). The objective of this study was to characterize the biofilm formation phenotype of the BF-EIEC O96:H19 strain 52.1 isolated from a child with moderate-to-severe gastroenteritis in Colombia. Random mutagenesis using Tn5 transposons identified 100 mutants unable to form biofilm; 20 of those had mutations within the pgaABCD operon. Site-directed mutagenesis of pgaB and pgaC confirmed the importance of these genes in N-acetylglucosamine-mediated biofilm formation. Both biofilm formation and TTSS-mediated host cell invasion were associated with host cell damage on the basis of cytotoxic assays comparing the wild type, invasion gene mutants, and biofilm formation mutants. Multilocus sequence typing-based phylogenetic analysis showed that BF-EIEC strain 52.1 does not cluster with classic EIEC serotype strains. Instead, BF-EIEC strain 52.1 clusters with EIEC serotype O96:H19 strains described in Europe and Uruguay. In conclusion, BF-EIEC O96:H19, an emerging pathogen associated with moderate-to-severe acute gastroenteritis in children under 5 years of age in Colombia, invades cells and has a strong biofilm formation capability. Both phenotypes are independently associated with in vitro cell cytotoxicity, and they may explain, at least in part, the higher disease severity reported in Europe and Latin America. IMPORTANCE Enteroinvasive Escherichia coli (EIEC), a close relative of Shigella, is implicated in dysenteric diarrhea. EIEC pathogenicity involves cell invasion mediated by effector proteins delivered by a type III secretion system (TTSS) that disrupt the cell cytoskeleton. These proteins and the VirF global regulator are encoded by a large (>200 kb) invasion plasmid (pINV). This study reports an emergent EIEC possessing a cell invasion phenotype and a strong polysaccharide matrix-mediated biofilm formation phenotype. Both phenotypes contribute to host cell cytotoxicity in vitro and may contribute to the severe disease reported among children and adults in Europe and Latin America.
Assuntos
Infecções por Escherichia coli , Gastroenterite , Shigella , Biofilmes , Pré-Escolar , Escherichia coli/genética , Infecções por Escherichia coli/microbiologia , Gastroenterite/microbiologia , Humanos , Filogenia , Shigella/genética , Sistemas de Secreção Tipo IIIRESUMO
BACKGROUND: The World Health Organization considers climate change an urgent global health challenge requiring prioritised action. A recent global survey reported that only 15% of medical schools have incorporated climate change and health into the curriculum. OBJECTIVES: This research study was carried out from November 2020 and April 2021 using the Planetary Health Report Card (PHRC) initiative to assess the current level of planetary health teaching in medical schools in the Republic of Ireland. PHRC is a student-led international public initiative, which aims to compare medical schools using a planetary health report card. The assessment was submitted as a final report to the Irish Medical Council and to the medical schools involved. RESULTS: Very few learning outcomes in Irish medical curricula directly address or include the concept of planetary health. Inclusion of specific topics remains reliant on individual lecturer interest. While most universities have excellent research centres which cover specific aspects of planetary health, the links between these institutes and medical schools have not been created. CONCLUSIONS: Overall, there are promising examples of planetary health themes throughout the current Irish medical curricula, however, these remain poorly implemented or embedded within the curricula. Medical schools should incorporate education on planetary health to ensure graduates are equipped as to become medical leaders practising in a changing world.
Assuntos
Educação de Graduação em Medicina , Educação Médica , Humanos , Irlanda , Currículo , Faculdades de Medicina , Educação em Saúde , Inquéritos e QuestionáriosRESUMO
Chronic infection with Helicobacter pylori increases risk of gastric diseases including gastric cancer. Despite development of a robust immune response, H.â pylori persists in the gastric niche. Progression of gastric inflammation to serious disease outcomes is associated with infection with H.â pylori strains which encode the cag Typeâ IV Secretion System (cagâ T4SS). The cag T4SS is responsible for translocating the oncogenic protein CagA into host cells and inducing pro-inflammatory and carcinogenic signaling cascades. Our previous work demonstrated that nutrient iron modulates the activity of the T4SS and biogenesis of T4SS pili. In response to H.â pylori infection, the host produces a variety of antimicrobial molecules, including the iron-binding glycoprotein, lactoferrin. Our work shows that apo-lactoferrin exerts antimicrobial activity against H.â pylori under iron-limited conditions, while holo-lactoferrin enhances bacterial growth. Culturing H.â pylori in the presence of holo-lactoferrin prior to co-culture with gastric epithelial cells, results in repression of the cagâ T4SS activity. Concomitantly, a decrease in biogenesis of cagâ T4SS pili at the host-pathogen interface was observed under these culture conditions by high-resolution electron microscopy analyses. Taken together, these results indicate that acquisition of alternate sources of nutrient iron plays a role in regulating the pro-inflammatory activity of a bacterial secretion system and present novel therapeutic targets for the treatment of H.â pylori-related disease.
Assuntos
Helicobacter pylori/efeitos dos fármacos , Lactoferrina/farmacologia , Sistemas de Secreção Tipo IV/metabolismo , Animais , Modelos Animais de Doenças , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Mucosa Gástrica/citologia , Mucosa Gástrica/metabolismo , Gerbillinae , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/microbiologia , Helicobacter pylori/metabolismo , Imunidade Inata , Interleucina-8/metabolismo , Ferro/metabolismo , Lactoferrina/química , Lactoferrina/metabolismo , Lactoferrina/uso terapêutico , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/farmacologia , Isoformas de Proteínas/uso terapêutico , Sistemas de Secreção Tipo IV/antagonistas & inibidoresRESUMO
BACKGROUND: The study objective was to compare the ISS manually assigned by hospital personnel and those generated by the ICDPIC software for value agreement and predictive power of length of stay (LOS) and mortality. METHODS: We used data from the 2010-2016 trauma registry of a paediatric trauma centre (PTC) and 2014 National Trauma Data Bank (NTDB) hospitals that reported manually coded ISS. Agreement analysis was performed between manually and computer assigned ISS with severity groupings of 1-8, 9-15, 16-25 and 25-75. The prediction of LOS was compared using coefficients of determination (R2) from linear regression models. Mortality predictive power was compared using receiver operating characteristic (ROC) curves from logistic regression models. RESULTS: The proportion of agreement between manually and computer assigned ISS in PTC data was 0.84 and for NTDB was 0.75. Analysing predictive power for LOS in the PTC sample, the R2=0.19 for manually assigned scores, and the R2=0.15 for computer assigned scores (p=0.0009). The areas under the ROC curve indicated a mortality predictive power of 0.95 for manually assigned scores and 0.86 for computer assigned scores in the PTC data (p=0.0011). CONCLUSIONS: Manually and computer assigned ISS had strong comparative agreement for minor injuries but did not correlate well for critical injuries (ISS=25-75). The LOS and mortality predictive power were significantly higher for manually assigned ISS when compared with computer assigned ISS in both PTC and NTDB data sets. Thus, hospitals should be cautious about transitioning to computer assigned ISS, specifically for patients who are critically injured.
Assuntos
Centros de Traumatologia , Ferimentos e Lesões , Criança , Computadores , Humanos , Escala de Gravidade do Ferimento , Modelos Logísticos , Valor Preditivo dos Testes , Curva ROCRESUMO
UNLABELLED: Helicobacter pylori must be able to rapidly respond to fluctuating conditions within the stomach. Despite this need for constant adaptation, H. pylori encodes few regulatory proteins. Of the identified regulators, the ferric uptake regulator (Fur), the nickel response regulator (NikR), and the two-component acid response system (ArsRS) are each paramount to the success of this pathogen. While numerous studies have individually examined these regulatory proteins, little is known about their combined effect. Therefore, we constructed a series of isogenic mutant strains that contained all possible single, double, and triple regulatory mutations in Fur, NikR, and ArsS. A growth curve analysis revealed minor variation in growth kinetics across the strains; these were most pronounced in the triple mutant and in strains lacking ArsS. Visual analysis showed that strains lacking ArsS formed large aggregates and a biofilm-like matrix at the air-liquid interface. Biofilm quantification using crystal violet assays and visualization via scanning electron microscopy (SEM) showed that all strains lacking ArsS or containing a nonphosphorylatable form of ArsR (ArsR-D52N mutant) formed significantly more biofilm than the wild-type strain. Molecular characterization of biofilm formation showed that strains containing mutations in the ArsRS pathway displayed increased levels of cell aggregation and adherence, both of which are key to biofilm development. Furthermore, SEM analysis revealed prevalent coccoid cells and extracellular matrix formation in the ArsR-D52N, ΔnikR ΔarsS, and Δfur ΔnikR ΔarsS mutant strains, suggesting that these strains may have an exacerbated stress response that further contributes to biofilm formation. Thus, H. pylori ArsRS has a previously unrecognized role in biofilm formation. IMPORTANCE: Despite a paucity of regulatory proteins, adaptation is key to the survival of H. pylori within the stomach. While prior studies have focused on individual regulatory proteins, such as Fur, NikR, and ArsRS, few studies have examined the combined effect of these factors. Analysis of isogenic mutant strains that contained all possible single, double, and triple regulatory mutations in Fur, NikR, and ArsS revealed a previously unrecognized role for the acid-responsive two-component system ArsRS in biofilm formation.
Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica/fisiologia , Helicobacter pylori/fisiologia , Transativadores/metabolismo , Proteínas de Bactérias/genética , Helicobacter pylori/genética , Helicobacter pylori/ultraestrutura , Transativadores/genéticaRESUMO
During infectious processes, antimicrobial proteins are produced by both epithelial cells and innate immune cells. Some of these antimicrobial molecules function by targeting transition metals and sequestering these metals in a process referred to as "nutritional immunity." This chelation strategy ultimately starves invading pathogens, limiting their growth within the vertebrate host. Recent evidence suggests that these metal-binding antimicrobial molecules have the capacity to affect bacterial virulence, including toxin secretion systems. Our previous work showed that the S100A8/S100A9 heterodimer (calprotectin, or calgranulin A/B) binds zinc and represses the elaboration of the H. pylori cag type IV secretion system (T4SS). However, there are several other S100 proteins that are produced in response to infection. We hypothesized that the zinc-binding protein S100A12 (calgranulin C) is induced in response to H. pylori infection and also plays a role in controlling H. pylori growth and virulence. To test this, we analyzed gastric biopsy specimens from H. pylori-positive and -negative patients for S100A12 expression. These assays showed that S100A12 is induced in response to H. pylori infection and inhibits bacterial growth and viability in vitro by binding nutrient zinc. Furthermore, the data establish that the zinc-binding activity of the S100A12 protein represses the activity of the cag T4SS, as evidenced by the gastric cell "hummingbird" phenotype, interleukin 8 (IL-8) secretion, and CagA translocation assays. In addition, high-resolution field emission gun scanning electron microscopy (FEG-SEM) was used to demonstrate that S100A12 represses biogenesis of the cag T4SS. Together with our previous work, these data reveal that multiple S100 proteins can repress the elaboration of an oncogenic bacterial surface organelle.
Assuntos
Infecções por Helicobacter/imunologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/imunologia , Helicobacter pylori/fisiologia , Proteínas S100/metabolismo , Adulto , Biópsia , Mucosa Gástrica/patologia , Infecções por Helicobacter/patologia , Helicobacter pylori/crescimento & desenvolvimento , Helicobacter pylori/patogenicidade , Humanos , Viabilidade Microbiana , Microscopia Eletrônica de Varredura , Proteína S100A12 , Virulência , Zinco/metabolismoRESUMO
Bacteria alter their cell surface in response to changing environments, including those encountered upon invasion of a host during infection. One alteration that occurs in several Gram-positive pathogens is the presentation of cell wall-anchored components of the iron-regulated surface determinant (Isd) system, which extracts heme from host hemoglobin to fulfill the bacterial requirement for iron. Staphylococcus lugdunensis, an opportunistic pathogen that causes infective endocarditis, encodes an Isd system. Unique among the known Isd systems, S. lugdunensis contains a gene encoding a putative autolysin located adjacent to the Isd operon. To elucidate the function of this putative autolysin, here named IsdP, we investigated its contribution to Isd protein localization and hemoglobin-dependent iron acquisition. S. lugdunensis IsdP was found to be iron regulated and cotranscribed with the Isd operon. IsdP is a specialized peptidoglycan hydrolase that cleaves the stem peptide and pentaglycine crossbridge of the cell wall and alters processing and anchoring of a major Isd system component, IsdC. Perturbation of IsdC localization due to isdP inactivation results in a hemoglobin utilization growth defect. These studies establish IsdP as an autolysin that functions in heme acquisition and describe a role for IsdP in cell wall reorganization to accommodate nutrient uptake systems during infection.
Assuntos
Parede Celular/metabolismo , Ferro/metabolismo , N-Acetil-Muramil-L-Alanina Amidase/metabolismo , Infecções Estafilocócicas/metabolismo , Staphylococcus lugdunensis/metabolismo , Proteínas de Bactérias/metabolismo , Imunofluorescência , Immunoblotting , Espectrometria de Massas , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
BACKGROUND: Prior studies of undertriage have not made comparisons across multiple trauma levels. METHODS: Emergency department data was extracted from the Nationwide Emergency Department Sample for major trauma patients. We considered patients with moderate injuries (Injury Severity Score, ISS=16-24) and severe injuries (ISS=25-75) separately. Conditional logistic regression modeling was used to compare the odds of ED mortality for level I trauma centers (TC I) vs. nontrauma centers (NTC) and level II trauma centers (TC II) vs. NTC. An innovative 1:1:1 optimal matching (an extension of the traditional pair matching) was used to balance patient characteristics in three groups. To facilitate matching of all NTC patients, 3 subgroups were developed for ISS=16-24 and 2 subgroups for ISS=25-75. Sensitivity analyses were performed to assess the strength of the association between trauma center designation and ED mortality. RESULTS: For ISS=16-24, 2 of 3 subgroups had marginally significant reduced odds of ED mortality when properly triaged (TC I vs. NTC [T1:OR=0.63; 95%CI: 0.45 - 0.89, T2:OR=0.71;95%CI:0.51-0.99]). For ISS=25-75, both subgroups had significantly reduced odds of emergency department mortality when properly triaged (H1: TC I vs. NTC [OR=0.61; 95%CI: 0.50-0.74]; TC II vs. NTC [OR=0.49; 95%CI: 0.38 - 0.63]; H2: TC I vs. NTC [OR=0.50; 95%CI: 0.41 - 0.60]; TC II vs. NTC [OR=0.42; 95%CI: 0.33 - 0.53]). Conclusions for ISS 25-75 were robust to a hypothesized unobserved confounding variable as shown in sensitivity analysis. CONCLUSIONS: Trauma patients with ISS≥25 received most benefit from proper triage. Efforts to reduce undertriage should focus on this population.
Assuntos
Serviço Hospitalar de Emergência , Centros de Traumatologia , Triagem , Ferimentos e Lesões/mortalidade , Adolescente , Adulto , Feminino , Humanos , Escala de Gravidade do Ferimento , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Estados Unidos/epidemiologia , Adulto JovemRESUMO
BACKGROUND: There is evidence that regionalized trauma care and appropriate triage of major trauma patients improve patient outcomes. However, the national rate of undertriage and diagnoses of undertriaged patients are unknown. METHODS: We used the 2010 Nationwide Emergency Department Sample to estimate the national rate of undertriage, identify the prevalent diagnoses, and conduct a simulation analysis of the capacity increase required for level I and II trauma centers (TCs) to accommodate undertriaged patients. Undertriaged patients were those with major trauma, injury severity score ≥ 16, who received definitive care at nontrauma centers (NTCs), or level III TCs. The rate of undertriage was calculated with those receiving definitive care at an NTC center or level III center as a fraction of all major trauma patients. RESULTS: The estimated number of major trauma patient discharges in 2010 was 232448. Level of care was known for 197702 major trauma discharges, and 34.0% were undertriaged in emergency departments (EDs). Elderly patients were at a significantly higher risk of being undertriaged. Traumatic brain injury (TBI) was the most common diagnosis, 40.2% of the undertriaged patient diagnoses. To accommodate all undertriaged patients, level I and II TCs nationally would have to increase their capacity by 51.5%. CONCLUSIONS: We found that more than one-third of US ED major trauma patients were undertriaged, and more than 40% of undertriaged diagnoses were TBIs. A significant capacity increase at level I and II TCs to accommodate these patients appears not feasible.
Assuntos
Serviço Hospitalar de Emergência/estatística & dados numéricos , Triagem/estatística & dados numéricos , Ferimentos e Lesões/diagnóstico , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Serviço Hospitalar de Emergência/normas , Feminino , Humanos , Lactente , Recém-Nascido , Cobertura do Seguro/estatística & dados numéricos , Seguro Saúde/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Centros de Traumatologia/normas , Centros de Traumatologia/estatística & dados numéricos , Triagem/normas , Estados Unidos/epidemiologia , Ferimentos e Lesões/mortalidade , Ferimentos e Lesões/terapia , Adulto JovemRESUMO
OBJECTIVE: To evaluate the definition of traumatic brain injury (TBI) in the National Electronic Injury Surveillance System (NEISS) and compare TBI case ascertainment using NEISS vs. ICD-9-CM diagnosis coding. METHODS: Two data samples from a NEISS participating emergency department (ED) in 2008 were compared: (1) NEISS records meeting the recommended NEISS TBI definition and (2) Hospital ED records meeting the ICD-9-CM CDC recommended TBI definition. The sensitivity and positive predictive value were calculated for the NEISS definition using the ICD-9-CM definition as the gold standard. Further analyses were performed to describe cases characterized as TBIs in both datasets and to determine why some cases were not classified as TBIs in both datasets. RESULTS: There were 1834 TBI cases captured by the NEISS and 1836 TBI cases captured by the ICD-9-CM coded ED record, but only 1542 were eligible for inclusion in NEISS. There were 1403 cases classified as TBIs by both the NEISS and ICD-9-CM diagnosis codes. The NEISS TBI definition had a sensitivity of 91.0% (95% CI = 89.6-92.4%) and positive predictive value of 76.5% (95% CI = 74.6-78.4%). CONCLUSIONS: Using the NEISS TBI definition presented in this paper would standardize and improve the accuracy of TBI research using the NEISS.
Assuntos
Lesões Encefálicas/classificação , Serviço Hospitalar de Emergência/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Classificação Internacional de Doenças , Sistema de Registros , Adolescente , Lesões Encefálicas/epidemiologia , Criança , Pré-Escolar , Reações Falso-Negativas , Reações Falso-Positivas , Feminino , Humanos , Lactente , Modelos Logísticos , Masculino , Vigilância da População , Sensibilidade e Especificidade , Estados UnidosRESUMO
Perinatal infection with Streptococcus agalactiae, or Group B Streptococcus (GBS), is associated with preterm birth, neonatal sepsis, and stillbirth. Here, we study the interactions of GBS with macrophages, essential sentinel immune cells that defend the gravid reproductive tract. Transcriptional analyses of GBS-macrophage co-cultures reveal enhanced expression of a gene encoding a putative metal resistance determinant, cadD. Deletion of cadD reduces GBS survival in macrophages, metal efflux, and resistance to metal toxicity. In a mouse model of ascending infection during pregnancy, the ΔcadD strain displays attenuated bacterial burden, inflammation, and cytokine production in gestational tissues. Furthermore, depletion of host macrophages alters cytokine expression and decreases GBS invasion in a cadD-dependent fashion. Our results indicate that GBS cadD plays an important role in metal detoxification, which promotes immune evasion and bacterial proliferation in the pregnant host.
Assuntos
Nascimento Prematuro , Streptococcus agalactiae , Animais , Citocinas , Feminino , Humanos , Recém-Nascido , Contagem de Leucócitos , Macrófagos/microbiologia , Metais , Camundongos , Gravidez , Nascimento Prematuro/microbiologia , Streptococcus agalactiae/genéticaRESUMO
Staphylococcus lugdunensis is often found as part of the normal flora of human skin but has the potential to cause serious infections even in healthy individuals. It remains unclear what factors enable S. lugdunensis to transition from a skin commensal to an invasive pathogen. Analysis of the complete genome reveals a putative iron-regulated surface determinant (Isd) system encoded within S. lugdunensis. In other bacteria, the Isd system permits the utilization of host heme as a source of nutrient iron to facilitate bacterial growth during infection. In this study, we establish that S. lugdunensis expresses an iron-regulated IsdG-family heme oxygenase that binds and degrades heme. Heme degradation by IsdG results in the release of free iron and the production of the chromophore staphylobilin. IsdG-mediated heme catabolism enables the use of heme as a sole source of iron, establishing IsdG as a pathophysiologically relevant heme oxygenase in S. lugdunensis. Together these findings offer insight into how S. lugdunensis fulfills its nutritional requirements while invading host tissues and establish the S. lugdunensis Isd system as being involved in heme-iron utilization.
Assuntos
Heme/metabolismo , Ferro/metabolismo , Oxigenases/metabolismo , Staphylococcus lugdunensis/enzimologia , Staphylococcus lugdunensis/metabolismo , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular , Oxirredução , Filogenia , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
Degradation of specific native proteins allows bacteria to rapidly adapt to changing environments when the activity of those proteins is no longer required. Although these processes are vital to bacterial survival, relatively little is known regarding how bacterial proteins are recognized and targeted for degradation. Staphylococcus aureus is an important human pathogen that requires iron for growth and pathogenesis. In the vertebrate host, S. aureus fulfills its iron requirement by obtaining heme iron from host hemoproteins via IsdG- and IsdI-mediated heme degradation. IsdG and IsdI are structurally and mechanistically analogous but are differentially regulated by iron and heme availability. Specifically, IsdG is targeted for degradation in the absence of heme. Therefore, we utilized the differential regulation of IsdG and IsdI to investigate the mechanism of regulated proteolysis. In contrast to canonical protease recognition sequences, we show that IsdG is targeted for degradation by internally coded sequences. Specifically, a flexible loop near the heme-binding pocket is required for IsdG degradation in the absence of heme.
Assuntos
Heme/deficiência , Oxigenases/química , Oxigenases/metabolismo , Staphylococcus aureus/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Marcação de Genes , Heme/genética , Hemeproteínas/metabolismo , Humanos , Ferro/química , Ferro/metabolismo , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Proteínas Mutantes Quiméricas/química , Proteínas Mutantes Quiméricas/genética , Proteínas Mutantes Quiméricas/metabolismo , Oxigenases/genética , Mutação Puntual , Conformação Proteica , Desnaturação Proteica , Estabilidade Proteica , Staphylococcus aureus/genéticaRESUMO
Epsilonproteobacteria are a diverse class of eubacteria within the Proteobacteria phylum that includes environmental sulfur-reducing bacteria and the human pathogens, Campylobacter jejuni and Helicobacter pylori. These pathogens infect and proliferate within the gastrointestinal tracts of multiple animal hosts, including humans, and cause a variety of disease outcomes. While infection of these hosts provides nutrients for the pathogenic Epsilonproteobacteria, many hosts have evolved a variety of strategies to either sequester metals from the invading pathogen or exploit the toxicity of metals and drive their accumulation as an antimicrobial strategy. As a result, C. jejuni and H. pylori have developed mechanisms to sense changes in metal availability and regulate their physiology in order to respond to either metal limitation or accumulation. In this review, we will discuss the challenges of metal availability at the host-pathogen interface during infection with C. jejuni and H. pylori and describe what is currently known about how these organisms alter their gene expression and/or deploy bacterial virulence factors in response to these environments.
Assuntos
Campylobacter jejuni/metabolismo , Helicobacter pylori/metabolismo , Homeostase , Metais Pesados/metabolismo , Transporte BiológicoRESUMO
Ongoing advancements in the treatment of acute myocardial infarction (MI) have significantly decreased MI related mortality. Consequently, the number of patients experiencing post-MI heart failure (HF) has continued to rise. Infarction size and the extent of left ventricular (LV) remodeling are largely determined by the extent of ischemia at the time of myocardial injury. In the setting of MI or acute phase of post-MI LV remodeling, anti-inflammatory drugs including intravenous immunoglobulin (IVIG) and Pentoxifylline have shown potential efficacy in preventing post-MI remodeling in-vitro and in some clinical trials. However, systemic administration of anti-inflammatory drugs are not without their off-target side effects. Herein, we explore the clinical feasibility of targeted myocardial delivery of anti-inflammatory drugs via biodegradable polymers, liposomes, hydrogels, and nano-particle based drug delivery models (NDDM) based on existing pre-clinical and clinical models. We summarize the barriers to clinical application of targeted anti-inflammatory delivery post-MI, including challenges in achieving sufficient retention and distribution, as well as the potential need for multiple dosing. Collectively, we suggest that localized delivery of anti-inflammatory agents to the myocardium using NDDM is a promising approach for successful treatment of ischemic HF. Future studies will be instrumental in determining the most effective target and delivery modalities for orchestrating NDDM-mediated treatment of HF.
Assuntos
Anti-Inflamatórios/administração & dosagem , Insuficiência Cardíaca/tratamento farmacológico , Infarto do Miocárdio/tratamento farmacológico , Animais , Anti-Inflamatórios/farmacologia , Sistemas de Liberação de Medicamentos , Insuficiência Cardíaca/etiologia , Humanos , Hidrogéis , Lipossomos , Infarto do Miocárdio/complicações , Isquemia Miocárdica/complicações , Isquemia Miocárdica/tratamento farmacológico , Nanopartículas , Remodelação Ventricular/efeitos dos fármacosRESUMO
Podocyte loss plays a pivotal role in the pathogenesis of glomerular disease. However, the mechanisms underlying podocyte damage and loss remain poorly understood. Although detachment of viable cells has been documented in experimental Diabetic Nephropathy, correlations between reduced podocyte density and disease severity have not yet been established. YAP, a mechanosensing protein, has recently been shown to correlate with glomerular disease progression, however, the underlying mechanism has yet to be fully elucidated. In this study, we sought to document podocyte density in Diabetic Nephropathy using an amended podometric methodology, and to investigate the interplay between YAP and cytoskeletal integrity during podocyte injury. Podocyte density was quantified using TLE4 and GLEPP1 multiplexed immunofluorescence. Fourteen Diabetic Nephropathy cases were analyzed for both podocyte density and cytoplasmic translocation of YAP via automated image analysis. We demonstrate a significant decrease in podocyte density in Grade III/IV cases (124.5 per 106 µm3) relative to Grade I/II cases (226 per 106 µm3) (Student's t-test, p < 0.001), and further show that YAP translocation precedes cytoskeletal rearrangement following injury. Based on these findings we hypothesize that a significant decrease in podocyte density in late grade Diabetic Nephropathy may be explained by early cytoplasmic translocation of YAP.
RESUMO
Triple-negative breast cancer (TNBC) is a subtype of breast cancer without a targeted form of therapy. Unfortunately, up to 70% of patients with TNBC develop resistance to treatment. A known contributor to chemoresistance is dysfunctional mitochondrial apoptosis signaling. We set up a phenotypic small-molecule screen to reveal vulnerabilities in TNBC cells that were independent of mitochondrial apoptosis. Using a functional genetic approach, we identified that a "hit" compound, BAS-2, had a potentially similar mechanism of action to histone deacetylase inhibitors (HDAC). An in vitro HDAC inhibitor assay confirmed that the compound selectively inhibited HDAC6. Using state-of-the-art acetylome mass spectrometry, we identified glycolytic substrates of HDAC6 in TNBC cells. We confirmed that inhibition or knockout of HDAC6 reduced glycolytic metabolism both in vitro and in vivo. Through a series of unbiased screening approaches, we have identified a previously unidentified role for HDAC6 in regulating glycolytic metabolism.
Assuntos
Neoplasias de Mama Triplo Negativas , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Detecção Precoce de Câncer , Desacetilase 6 de Histona/genética , Desacetilase 6 de Histona/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Humanos , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismoRESUMO
Calgranulin proteins are an important class of molecules involved in innate immunity. These members of the S100 class of the EF-hand family of calcium-binding proteins have numerous cellular and antimicrobial functions. One protein in particular, S100A12 (also called EN-RAGE or calgranulin C), is highly abundant in neutrophils during acute inflammation and has been implicated in immune regulation. Structure-function analyses reveal that S100A12 has the capacity to bind calcium, zinc, and copper, processes that contribute to nutritional immunity against invading microbial pathogens. S100A12 is a ligand for the receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), and CD36, which promote cellular and immunological pathways to alter inflammation. We conducted a scoping review of the existing literature to define what is known about the association of S100A12 with digestive disease and health. Results suggest that S100A12 is implicated in gastroenteritis, necrotizing enterocolitis, gastritis, gastric cancer, Crohn's disease, irritable bowel syndrome, inflammatory bowel disease, and digestive tract cancers. Together, these results reveal S100A12 is an important molecule broadly associated with the pathogenesis of digestive diseases.
RESUMO
Streptococcal species are Gram-positive bacteria responsible for a variety of disease outcomes including pneumonia, meningitis, endocarditis, erysipelas, necrotizing fasciitis, periodontitis, skin and soft tissue infections, chorioamnionitis, premature rupture of membranes, preterm birth, and neonatal sepsis. In response to streptococcal infections, the host innate immune system deploys a repertoire of antimicrobial and immune modulating molecules. One important molecule that is produced in response to streptococcal infections is lactoferrin. Lactoferrin has antimicrobial properties including the ability to bind iron with high affinity and sequester this important nutrient from an invading pathogen. Additionally, lactoferrin has the capacity to alter the host inflammatory response and contribute to disease outcome. This Review presents the most recent published work that studies the interaction between the host innate immune protein lactoferrin and the invading pathogen, Streptococcus.
Assuntos
Anti-Infecciosos , Nascimento Prematuro , Infecções Estreptocócicas , Feminino , Humanos , Imunidade , Recém-Nascido , Lactoferrina/metabolismo , Gravidez , Infecções Estreptocócicas/tratamento farmacológicoRESUMO
PURPOSE: Invasive lobular carcinoma (ILC) is a subtype of breast cancer accounting for 10% of breast tumors. The majority of patients are treated with endocrine therapy; however, endocrine resistance is common in estrogen receptor-positive breast cancer and new therapeutic strategies are needed. Bromodomain and extraterminal inhibitors (BETi) are effective in diverse types of breast cancer but they have not yet been assessed in ILC. EXPERIMENTAL DESIGN: We assessed whether targeting the BET proteins with JQ1 could serve as an effective therapeutic strategy in ILC in both 2D and 3D models. We used dynamic BH3 profiling and RNA-sequencing (RNA-seq) to identify transcriptional reprograming enabling resistance to JQ1-induced apoptosis. As part of the RATHER study, we obtained copy-number alterations and RNA-seq on 61 ILC patient samples. RESULTS: Certain ILC cell lines were sensitive to JQ1, while others were intrinsically resistant to JQ1-induced apoptosis. JQ1 treatment led to an enhanced dependence on antiapoptotic proteins and a transcriptional rewiring inducing fibroblast growth factor receptor 1 (FGFR1). This increase in FGFR1 was also evident in invasive ductal carcinoma (IDC) cell lines. The combination of JQ1 and FGFR1 inhibitors was highly effective at inhibiting growth in both 2D and 3D models of ILC and IDC. Interestingly, we found in the RATHER cohort of 61 ILC patients that 20% had FGFR1 amplification and we showed that high BRD3 mRNA expression was associated with poor survival specifically in ILC. CONCLUSIONS: We provide evidence that BETi either alone or in combination with FGFR1 inhibitors or BH3 mimetics may be a useful therapeutic strategy for recurrent ILC patients.