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As antibiotic-resistant bacteria continue to emerge frequently, bacterial infections have become a significant and pressing challenge to global public health. Innate immunity triggers the activation of host responses by sensing "non-self" components through various pattern recognition receptors (PRRs), serving as the first line of antibacterial defense. Stimulator of interferon genes (STING) is a PRR that binds with cyclic dinucleotides (CDN) to exert effects against bacteria, viruses, and cancer by inducing the production of type I interferon and inflammatory cytokines, and facilitating regulated cell death. Currently, drugs targeting the STING signaling pathway are predominantly applied in the fields of modulating host immune defense against cancer and viral infections, with relatively limited application in treating bacterial infections. Given the significant immunomodulatory functions of STING in the interaction between bacteria and hosts, this review summarizes the research progress on STING signaling pathways and their roles in bacterial infection, as well as the novel functions of STING modulators, aiming to offer insights for the development of antibacterial drugs.
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BACKGROUND: Acute aortic dissection (AD) in pregnancy poses a lethal risk to both mother and fetus. However, well-established therapeutic guidelines are lacking. This study aimed to investigate clinical features, outcomes and optimal management strategies for pregnancy-related AD. METHODS: We conducted a retrospective multicentre cohort study including 67 women with acute AD during pregnancy or within 12 weeks postpartum from three major cardiovascular centres in China between 2003 and 2021. Patient characteristics, management strategies and short-term outcomes were analysed. RESULTS: Median age was 31 years, with AD onset at median 32 weeks gestation. Forty-six patients (68.7%) had type A AD, of which 41 underwent immediate surgery. Overall maternal mortality was 10.4% (7/67) and fetal mortality was 26.9% (18/67). Compared with immediate surgery, selective surgery was associated with higher risk of composite maternal and fetal death (adjusted RR: 12.47 (95% CI 3.26 to 47.73); p=0.0002) and fetal death (adjusted RR: 8.77 (95% CI 2.33 to 33.09); p=0.001). CONCLUSIONS: Immediate aortic surgery should be considered for type A AD at any stage of pregnancy or postpartum. For pregnant women with AD before fetal viability, surgical treatment with the fetus in utero should be considered. Management strategies should account for dissection type, gestational age, and fetal viability. TRIAL REGISTRATION NUMBER: NCT05501145.
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Cladosporium and Epicoccum are cosmopolitan fungi of the class Dothideomycetes with few cultured and genomic representatives. Here, we report draft reference genome sequences of Epicoccum sp. F181 (GenBank accession number JAJSLS01), Cladosporium sp. F165 (JAJSLR01), and F190 (JAJSLT01) isolated from recycling and waste management facilities in New Zealand.
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Background: Although genome-wide association studies (GWAS) have identified 14 loci associated with frailty index (FI) susceptibility, the underlying causative genes and biological mechanisms remain elusive. Methods: A cross-tissue transcriptome-wide association study (TWAS) was conducted utilizing the Unified Test for Molecular Markers (UTMOST), which integrates GWAS summary statistics from 164,610 individuals of European ancestry and 10,616 Swedish participants, alongside gene expression matrices from the Genotype-Tissue Expression (GTEx) Project. Validation of the significant genes was performed through three distinct methods: FUSION, FOCUS, and Multiple Marker Analysis of Genome-wide Annotation (MAGMA). Exploration of tissue and functional enrichment for FI-associated SNPs was conducted using MAGMA. Conditional and joint analyses, along with fine mapping, were employed to enhance our understanding of FI's genetic architecture. Mendelian randomization was employed to ascertain causal relationships between significant genes and FI, and co-localization analysis was utilized to investigate shared SNPs between significant genes and FI. Results: In this study, two novel susceptibility genes associated with the risk of FI were identified through the application of four TWAS methods. Mendelian randomization demonstrated that HTT may elevate the risk of developing frailty, whereas LRPPRC could offer protection against the onset of frailty. Additionally, co-localization analysis identified a shared SNP between LRPPRC and FI. Tissue enrichment analyses revealed that genomic regions linked to SNPs associated with frailty were predominantly enriched in various brain regions, including the frontal cortex, cerebral cortex, and cerebellar hemispheres. Conditional, combined analyses, and fine mapping collectively identified two genetic regions associated with frailty: 2p21 and 4q16.3. Functional enrichment analyses revealed that the pathways associated with frailty were primarily related to the MHC complex, PD-1 signaling, cognition, inflammatory response to antigenic stimuli, and the production of second messenger molecules. Conclusion: This investigation uncovers two newly identified genes with forecasted expression levels associated with the risk of FI, offering new perspectives on the genetic architecture underlying FI.
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Tears in the lateral meniscus, especially the body and posterior horn, are a common sports medicine injury, and severe cases require arthroscopic treatment. However, the narrow space in the posterolateral compartment of the knee joint makes the surgeon's operation inconvenient. Here we have proposed a suture technique suitable for lateral meniscus posterior horn/body injuries known as the Chinese Union Suture Procedure. The introduction of the posteromedial-transseptal portal allows for a suitable angle of operation for suture hooks in case of injuries to the posterior horn of the lateral meniscus or the popliteal hiatus area of the lateral meniscus. The use of the continuous sewing machine-like suture technique allows surgeons to more quickly and flexibly address meniscus tears. We have also introduced a retractor as an auxiliary tool for portal establishment. In conclusion, our improved technique enables vertical mattress suturing for meniscus tears, and it allows for tying knots on the tibial surface of the meniscus, which is challenging to achieve with traditional all-inside suture hook techniques. Our technique combines flexibility, speed, and cost-effectiveness, making it valuable for clinical applications.
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The main method for arthroscopic repair of the subscapularis is repair with suture anchors. The surgeon generally establishes the anterior and anterolateral operation portals to complete anchor implantation and suture passing, respectively. The single-operation portal technique has been developed recently. However, in the traditional single-operation portal technique, the suture device and grasper are difficult to operate simultaneously. In addition, with the traditional rotator cuff suture device, it is easy to cause further iatrogenic injury to the rotator cuff because of its larger diameter. Therefore, we describe a modified single-operation portal technique for suture passing percutaneously with a spinal needle taking into account the shortcomings of existing techniques. Our modified technique avoids the use of traditional suturing devices and effectively avoids further damage to the rotator cuff. The use of a single operation portal makes the operation more minimally invasive and simple and effectively avoids the problem of interference between the suture device and grasper in the same portal. The entire operational process does not require the use of costly consumables, resulting in increased cost-effectiveness and a significantly reduced operating time. In conclusion, our modified technique achieves the use of a single operation portal to suture the subscapularis through spinal needle suture passing, which has good clinical value.
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Non-typhoidal Salmonella infection is among the most frequent foodborne diseases threatening human health worldwide. The host circadian clock orchestrates daily rhythms to adapt to environmental changes, including coordinating immune function in response to potential infections. However, the molecular mechanisms underlying the interplay between the circadian clock and the immune system in modulating infection processes are incompletely understood. Here, we demonstrate that NLRP6, a novel nucleotide-oligomerization domain (NOD)-like receptor (NLR) family member highly expressed in the intestine, is closely associated with the differential day-night response to Salmonella infection. The core clock component REV-ERBα negatively regulates NLRP6 transcription, leading to the rhythmic expression of NLRP6 and the secretion of IL-18 in intestinal epithelial cells, playing a crucial role in mediating the differential day-night response to Salmonella infection. Activating REV-ERBα with agonist SR9009 in wild-type mice attenuated the severity of infection by decreasing the NLRP6 level in intestinal epithelial cells. Our findings provide new insights into the association between the host circadian clock and the immune response to enteric infections by revealing the regulation of Salmonella infection via the inhibitory effect of REV-ERBα on NLRP6 transcription. Targeting REV-ERBα to modulate NLRP6 activation may be a potential therapeutic strategy for bacterial infections.
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Programmed cell death (PCD) is tightly orchestrated by molecularly defined executors and signaling pathways. NLRP6, a member of cytoplasmic pattern recognition receptors, has a multifaceted role in host resistance to bacterial infection. However, whether and how NLRP6 may contribute to regulate host PCD during Gram-negative bacterial infection remain to be illuminated. Here, we report that NLRP6 promotes RIP1 kinase-mediated necroptosis, a form of lytic PCD, in both an in vitro and in vivo model of Salmonella typhimurium infection. By downregulating TAK1-mediated p38MAPK/MK2 phosphorylation, NLRP6 decreased RIP1 phosphorylation at residue S321 and subsequently increased RIP1 kinase-dependent MLKL phosphorylation. Suppression of p38MAPK/MK2 cascade not only reduced the number of dead cells caused by NLRP6 but also decreased the systemic dissemination of S. typhimurium resulting from NLRP6. Taken together, our findings provide new insights into the role and regulatory mechanism of NLRP6-associated antimicrobial responses by revealing a function for NLRP6 in regulating necroptosis.
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To examine the factors that contribute to patient delays among individuals with chronic kidney disease (CKD) and offer insights to help develop specific risk management strategies. Conducted as a cross-sectional study between September 2021 and April 2022, this study used a convenient sampling technique to select 245 individuals diagnosed with CKD from a Grade 3 Class A hospital located in Shanxi Province. These individuals were chosen as the subjects of the study. The research participants underwent an investigation using several assessment tools, including socio-demographic information questionnaire, medical behavior, the social support rating scale, the simplified coping style questionnaire, and the General Self-efficacy Scale. The study revealed that 35.4% of individuals with CKD experienced patient delay (the interval between the initial onset and the time of seeking medical attention being longer than or equal to 3 months). Through a multifactorial logistic regression analysis, it was determined that various factors independently influenced patient delay in patients with CKD. These factors included the level of knowledge about CKD, educational level, frequency of attending physical examinations, severity of initial symptoms, social support, self-efficacy, positive coping, and negative coping. Numerous factors contribute to the Patient Delay. To effectively enhance awareness and coping abilities regarding CKD in high-risk groups, it is essential to implement focused and continuous interventions throughout the medical seeking process.
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Insuficiência Renal Crônica , Humanos , Estudos Transversais , Insuficiência Renal Crônica/terapia , AutoeficáciaRESUMO
The quality of pasteurized milk is commonly assessed through microbiological analysis, with variations in storage conditions significantly impacting the suppression of bacterial growth throughout the milk's shelf life. This study investigated the dynamics of total bacterial counts (TBCs) and bacterial community shifts in milk that underwent pasteurization at 80 °C for 15 s. The milk was subsequently stored at 4 °C for varying intervals of 1, 4, 7, 10, 13, and 16 days. Culture-based testing revealed a significant TBC increase during the storage period spanning 1 to 16 days (up to -log10 4.2 CFU/mL at day 16). The TBC in pasteurized milk exhibited accelerated microbial growth from day 13 onwards, ultimately peaking on day 16. Bacillus was detected through 16S rRNA identification. Principal component analysis demonstrated a significant impact of storage time on bacterial communities in pasteurized milk. Analysis of bacterial diversity revealed a negative correlation between the Shannon index and the duration of pasteurized milk storage. Using high-throughput sequencing, Streptococcus and Acinetobacter were detected as prevalent bacterial genera, with Streptococcus dysgalactiae and Streptococcus uberis showing as dominant taxa. The presence of Streptococcus dysgalactiae and Streptococcus uberis in pasteurized milk might be attributed to the initial contamination from raw milk with mastitis. This study offers new evidence of the prevalence of bacterial community in pasteurized milk, thereby adding value to the enhancement of quality control and the development of strategies for reducing microbial risks.
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Salmonella is responsible for the majority of food poisoning outbreaks around the world. Pathogenic Salmonella mostly carries a virulence plasmid that contains the Salmonella plasmid virulence gene (spv), a highly conserved sequence encoding effector proteins that can manipulate host cells. Intestinal epithelial cells are crucial components of the innate immune system, acting as the first barrier of defense against infection. When the barrier is breached, Salmonella encounters the underlying macrophages in lamina propria, triggering inflammation and engaging in combat with immune cells recruited by inflammatory factors. Host regulated cell death (RCD) provides a variety of means to fight against or favour Salmonella infection. However, Salmonella releases effector proteins to regulate RCD, evading host immune killing and neutralizing host antimicrobial effects. This review provides an overview of pathogen-host interactions in terms of (1) pathogenicity of Salmonella spv on intestinal epithelial cells and macrophages, (2) mechanisms of host RCD to limit or promote pathogenic Salmonella expansion, and (3) effects and mechanisms of Salmonella spv gene on host RCD.
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Morte Celular Regulada , Salmonella , Virulência/genética , Salmonella/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Plasmídeos/genéticaRESUMO
BACKGROUND: Pichia pastoris is a widely utilized host for heterologous protein expression and biotransformation. Despite the numerous strategies developed to optimize the chassis host GS115, the potential impact of changes in cell wall polysaccharides on the fitness and performance of P. pastoris remains largely unexplored. This study aims to investigate how alterations in cell wall polysaccharides affect the fitness and function of P. pastoris, contributing to a better understanding of its overall capabilities. RESULTS: Two novel mutants of GS115 chassis, H001 and H002, were established by inactivating the PAS_chr1-3_0225 and PAS_chr1-3_0661 genes involved in ß-glucan biosynthesis. In comparison to GS115, both modified hosts exhibited a looser cell surface and larger cell size, accompanied by faster growth rates and higher carbon-to-biomass conversion ratios. When utilizing glucose, glycerol, and methanol as exclusive carbon sources, the carbon-to-biomass conversion rates of H001 surpassed GS115 by 10.00%, 9.23%, and 33.33%, respectively. Similarly, H002 exhibited even higher increases of 32.50%, 12.31%, and 53.33% in carbon-to-biomass conversion compared to GS115 under the same carbon sources. Both chassis displayed elevated expression levels of green fluorescent protein (GFP) and human epidermal growth factor (hegf). Compared to GS115/pGAPZ A-gfp, H002/pGAPZ A-gfp showed a 57.64% higher GFP expression, while H002/pPICZα A-hegf produced 66.76% more hegf. Additionally, both mutant hosts exhibited enhanced biosynthesis efficiencies of S-adenosyl-L-methionine and ergothioneine. H001/pGAPZ A-sam2 synthesized 21.28% more SAM at 1.14 g/L compared to GS115/pGAPZ A-sam2, and H001/pGAPZ A-egt1E obtained 45.41% more ERG at 75.85 mg/L. The improved performance of H001 and H002 was likely attributed to increased supplies of NADPH and ATP. Specifically, H001 and H002 exhibited 5.00-fold and 1.55-fold higher ATP levels under glycerol, and 6.64- and 1.47-times higher ATP levels under methanol, respectively, compared to GS115. Comparative lipidomic analysis also indicated that the mutations generated richer unsaturated lipids on cell wall, leading to resilience to oxidative damage. CONCLUSIONS: Two novel P. pastoris chassis hosts with impaired ß-1,3-D-glucan biosynthesis were developed, showcasing enhanced performances in terms of growth rate, protein expression, and catalytic capabilities. These hosts exhibit the potential to serve as attractive alternatives to P. pastoris GS115 for various bioproduction applications.
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Metanol , Pichia , Saccharomycetales , Humanos , Pichia/metabolismo , Metanol/metabolismo , Glicerol/metabolismo , Trifosfato de Adenosina/metabolismo , Carbono/metabolismo , Parede Celular/metabolismo , Polissacarídeos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
Cronobacter sakazakii, an opportunistic milk-borne pathogen responsible for severe neonatal meningitis and bacteremia, can synthesize yellow pigment (various carotenoids) benefiting for bacterial survival, while little literature was available about the influence of various carotenoids on bacterial resistance to a series of stresses and the characteristics of cell membrane, obstructing the development of novel bactericidal strategies overcoming the strong tolerance of C. sakazakii. Thus in this study, for the first time, five carotenogenic genes of C. sakazakii BAA-894 were inactivated, respectively, to construct a series of mutants producing various carotenoids and their effects on the cell membrane properties, and resistances to food- and host-related stresses, were investigated systematically. Furthermore, to explore its possible mode of action, comparative lipidomics analysis was performed to reveal the change of lipids that were mainly located at cell membranes. The results showed that five mutants (ΔcrtB, ΔcrtI, ΔcrtY, ΔcrtZ, and ΔcrtX) displayed negligible change in growth rate but higher permeability of the outer membrane and lower fluidity of cell membrane compared to the wild type. Besides, these mutants exhibited poorer ability of biofilm formation and lower resistances to acid, oxidative, osmotic, and desiccation stresses, indicating that different carotenoid composition significantly affected environmental tolerance of C. sakazakii. To discover the possible causes, lipidomics analysis of C. sakazakii was conducted and more than 500 lipid species belonging to 27 classes had been identified at first. Compared to that of BAA-894, the composition and relative intensity of lipid species in five mutants varied significantly, especially the monounsaturated and biunsaturated phosphatidylethanolamine. The evidence presented in this study demonstrated that the varied composition of carotenoids in C. sakazakii significantly altered the lipid profile and intensity, which maybe a crucial means to influencing the characteristics of cell membranes and resistance to environmental stresses.
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Cronobacter sakazakii , Cronobacter , Recém-Nascido , Humanos , Cronobacter sakazakii/genética , Carotenoides/metabolismo , Estresse Fisiológico , LipídeosRESUMO
OBJECTIVE: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a representative model organism for investigating host-pathogen interactions. It was reported that S. Typhimurium spvC gene alleviated intestinal inflammation to aggravate systemic infection, while the precise mechanisms remain unclear. In this study, the influence of spvC on the antibacterial defense of macrophage/neutrophil mediated by gasdermin D (GSDMD) was investigated. METHODS: Mouse macrophage-like cell lines J774A.1 and RAW264.7, neutrophil-like cells derived from HL-60 cells (human promyletic leukemia cell lines) were infected with S. Typhimurium wild type, spvC deletion and complemented strains. Cell death was evaluated by LDH release and Annexin V-FITC/PI staining. Macrophage pyroptosis and neutrophil NETosis were detected by western blotting, live cell imaging and ELISA. Flow cytometry was used to assess the impact of spvC on macrophage-neutrophil cooperation in macrophage (dTHP-1)-neutrophil (dHL-60) co-culture model pretreated with GSDMD inhibitor disulfiram. Wild-type and Gsdmd-/- C57BL/6J mice were utilized for in vivo assay. The degree of phagocytes infiltration and inflammation were analyzed by immunofluorescence and transmission electron microscopy. RESULTS: Here we find that spvC inhibits pyroptosis in macrophages via Caspase-1/Caspase-11 dependent canonical and non-canonical pathways, and restrains neutrophil extracellular traps extrusion in GSDMD-dependent manner. Moreover, spvC could ameliorate macrophages/neutrophils infiltration and cooperation in the inflammatory response mediated by GSDMD to combat Salmonella infection. CONCLUSIONS: Our findings highlight the antibacterial activity of GSDMD in phagocytes and reveal a novel pathogenic mechanism employed by spvC to counteract this host defense, which may shed new light on designing effective therapeutics to control S. Typhimurium infection.
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Gasderminas , Neutrófilos , Animais , Camundongos , Humanos , Camundongos Endogâmicos C57BL , Salmonella , Macrófagos , Antibacterianos , Inflamação , CaspasesRESUMO
This study aimed to investigate the reasons for patient delay in chronic kidney disease (CKD) and provide a scientific basis for implementing effective interventions. With the adoption of the phenomenological method in qualitative research, semi-structured, face-to-face interviews were conducted with 14 cases, and the Colaizzi seven-step analysis method was used to analyze the interview data and refine the themes. A total of 4 themes were obtained, namely, a cognitive explanation of illness, negative psychological emotions, socioeconomic levels, and limited medical resources. The current status of patient delay in chronic kidney disease is serious, and there are various reasons for it. Health management departments and healthcare providers at all levels should pay attention to this situation and provide targeted supportive interventions and health education to help patients establish the correct awareness of medical consultation and effectively improve their quality of survival.
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Insuficiência Renal Crônica , Humanos , Insuficiência Renal Crônica/terapia , Insuficiência Renal Crônica/psicologia , Pesquisa Qualitativa , Pessoal de Saúde , Educação em SaúdeRESUMO
Hypoxic-ischemic brain damage (HIBD) can result in significant global rates of neonatal death or permanent neurological disability. N6-methyladenosine (m6A) modification of RNA influences fundamental aspects of RNA metabolism, and m6A dysregulation is implicated in various neurological diseases. However, the biological roles and clinical significance of m6A in HIBD remain unclear. We currently evaluated the effect of HIBD on cerebral m6A methylation in RNAs in neonatal rats. The m6A dot blot assay showed a global augmentation in RNA m6A methylation post-HI. Herein, we also report on demethylase FTO, which is markedly downregulated in the hippocampus and is the main factor involved with aberrant m6A modification following HI. By conducting a comprehensive analysis of RNA-seq data and m6A microarray results, we found that transcripts with m6A modifications were more highly expressed overall than transcripts without m6A modifications. The overexpression of FTO resulted in the promotion of Akt/mTOR pathway hyperactivation, while simultaneously inhibiting autophagic function. This is carried out by the demethylation activity of FTO, which selectively demethylates transcripts of phosphatase and tensin homolog (PTEN), thus promoting its degradation and reduced protein expression after HI. Moreover, the synaptic and neurocognitive disorders induced by HI were effectively reversed through the overexpression of FTO in the hippocampus. Cumulatively, these findings demonstrate the functional importance of FTO-dependent hippocampal m6A methylome in cognitive function and provides novel mechanistic insights into the therapeutic potentials of FTO in neonatal HIBD.
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Disfunção Cognitiva , RNA , Animais , Ratos , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Animais Recém-Nascidos , Disfunção Cognitiva/genética , RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Following the publication of the above article, an interested reader drew to the authors' attention that the 'Control' and 'miR218 / BMI1' data panels for the Transwell invasion assay experiments shown in Figs. 4D and 5D on p. 100 and 101 respectively contained apparently overlapping data, albeit presented in different orientations, such that these data would have been derived from the same original source, even though they were intended to have shown the results from different experiments. On reexamining their original data, the authors realized that they had inadvertently assembled the data from the Transwell assay experiments incorrectly in Figs. 2, 4 and 5. The authors elected to repeat these Transwell assay experiments in view of the errors made in assembling these figures, and the revised versions of Figs. 2, 4 and 5 (specificially, containing the replacement Transwell assay data in Figs. 2F, 4D and 5D) are shown on the next three pages. Note that the errors made in assembling these figures did not affect the overall conclusions reported in the paper. All the authors agree with the publication of this corrigendum, and are grateful to the Editor of International Journal of Molecular Medicine for granting them the opportunity to publish this. Furthermore, they apologize to the readership for any inconvenience caused. [International Journal of Molecular Medicine 36: 93102, 2015; DOI: 10.3892/ijmm.2015.2216].
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SopF, a newly discovered effector secreted by Salmonella pathogenicity island-1 type III secretion system (T3SS1), was reported to target phosphoinositide on host cell membrane and aggravate systemic infection, while its functional relevance and underlying mechanisms have yet to be elucidated. PANoptosis (pyroptosis, apoptosis, and necroptosis) of intestinal epithelial cells (IECs) has been characterized as a pivotal host defense to limit the dissemination of foodborne pathogens, whereas the effect of SopF on IECs PANoptosis induced by Salmonella is rather limited. Here, we show that SopF can attenuate intestinal inflammation and suppress IECs expulsion to promote bacterial dissemination in mice infected with Salmonella enterica serovar Typhimurium (S. Typhimurium). We revealed that SopF could activate phosphoinositide-dependent protein kinase-1 (PDK1) to phosphorylate p90 ribosomal S6 kinase (RSK) which down-regulated Caspase-8 activation. Caspase-8 inactivated by SopF resulted in inhibition of pyroptosis and apoptosis, but promotion of necroptosis. The administration of both AR-12 (PDK1 inhibitor) and BI-D1870 (RSK inhibitor) potentially overcame Caspase-8 blockade and subverted PANoptosis challenged by SopF. Collectively, these findings demonstrate that this virulence strategy elicited by SopF aggregates systemic infection via modulating IEC PANoptosis through PDK1-RSK signaling, which throws light on novel functions of bacterial effectors, as well as a mechanism employed by pathogens to counteract host immune defense.
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Microbioma Gastrointestinal , Animais , Camundongos , Caspase 8/metabolismo , Salmonella typhimurium/metabolismo , Células Epiteliais/metabolismo , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Fosfatidilinositóis/metabolismo , Proteínas de Bactérias/metabolismoRESUMO
Anaplasma phagocytophilum, the aetiologic agent of human granulocytic anaplasmosis (HGA), is an obligate intracellular Gram-negative bacterium. During infection, A. phagocytophilum enhances the adhesion of neutrophils to the infected endothelial cells. However, the bacterial factors contributing to this phenomenon remain unknown. In this study, we characterized a type IV secretion system substrate of A. phagocytophilum, AFAP (an actin filament-associated Anaplasma phagocytophilum protein) and found that it dynamically changed its pattern and subcellular location in cells and enhanced cell adhesion. Tandem affinity purification combined with mass spectrometry identified host nucleolin as an AFAP-interacting protein. Further study showed the disruption of nucleolin by RNA interference, and the treatment of a nucleolin-binding DNA aptamer AS1411 attenuated AFAP-mediated cell adhesion, indicating that AFAP enhanced cell adhesion in a nucleolin-dependent manner. The characterization of cell adhesion-enhancing AFAP and the identification of host nucleolin as its interaction partner may help understand the mechanism underlying A. phagocytophilum-promoting cell adhesion, facilitating the elucidation of HGA pathogenesis.
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Escherichia coli (E. coli) bloodstream infections (BSIs) are among the most predominant causes of death in infants and children worldwide. NDM-5 (New Delhi Metallo-lactamase-5) is responsible for one of the main mechanisms of carbapenem resistance in E. coli. To analyze the phenotypic and genomic characteristics of NDM-5-producing E. coli from bloodstream infections (BSIs), a total of 114 E. coli strains was collected from a children's hospital in Jiangsu province, China. Eight blaNDM-5-carrying E. coli strains were identified which were all carbapenem-resistant and carried diverse antimicrobial resistance genes apart from blaNDM-5. They belonged to six distinct sequence types (STs) and serotypes including one each for ST38/O7:H8, ST58/O?:H37, ST131/O25:H4, ST156/O11:H25 and ST361/O9:H30 and three strains are originating from a single clone belonging to ST410/O?:H9. Apart from blaNDM-5, the E. coli strains isolated from BSIs also carried other ß-lactamase genes, including blaCMY-2 (n = 4), blaCTX-M-14 (n = 2), blaCTX-M-15 (n = 3), blaCTX-M-65 (n = 1), blaOXA-1 (n = 4) and blaTEM-1B (n = 5). The blaNDM-5 genes were located on three different types of plasmids, which were IncFII/I1 (n = 1), IncX3 (n = 4) and IncFIA/FIB/FII/Q1 (n = 3). The former two types were conjugatively transferable at frequencies of 10-3 and 10-6, respectively. The dissemination of NDM-producing strains, which exhibit resistance to the last-line antibiotics, carbapenems, may increase the muti-antimicrobial resistance burden among E. coli BSIs and further threaten public health.