Effects of A. baumannii infection on A549 cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE300474 | GEO | 2026/08/31
REPOSITORIES: GEO
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Project description:The bacterial pathogen, Acinetobacter baumannii, is a leading cause of drug-resistant infections. Here, we investigated the potential of developing nanobodies that specifically recognize A. baumannii over other Gram-negative bacteria. Through generation and panning of a synthetic nanobody library, we identified several potential lead candidates. We demonstrate how incorporation of next generation sequencing analysis can aid in selection of lead candidates for further characterization. Using monoclonal phage display, we validated the binding of several lead nanobodies to A. baumannii. Subsequent purification and biochemical characterization revealed one particularly robust nanobody that broadly and specifically bound A. baumannii compared to other common drug resistant pathogens. These findings support the potentially for nanobodies to selectively target A. baumannii and the identification of lead candidates for possible future diagnostic and therapeutic development.
2023-06-21 | GSE202972 | GEO
Project description:Acinetobacter baumannii is a Gram-negative opportunistic pathogen that causes multiple infections, including pneumonia, bacteremia, and wound infections. Due to multiple intrinsic and acquired drug-resistance mechanisms, A. baumannii isolates are commonly multi-drug resistant and infections are notoriously difficult to treat. Therefore, it is important to identify mechanisms used by A. baumannii to survive stresses encountered during infection as a means of identifying new drug targets. In this study, we determined the transcriptional response of A. baumannii to hydrogen peroxide stress using RNASequencing. Upon exposure to hydrogen peroxide, A. baumannii differentially transcribes several hundred genes. In this study, we also determined the transcriptional profile of A. baumannii strains with the transcriptional regulators mumR or oxyR genetically inactivated and identified transcriptional differences between these strains and wild-type A. baumannii in response to hydrogen peroxide stress. In doing this, the function of A. baumannii OxyR in hydrogen peroxide stress resistance and regulation of genes required for hydrogen peroxide detoxification was defined. Moreover, the contribution of the uncharacterized regulator MumR to hydrogen peroxide stress resistance was also explored. This work reveals the transcriptome of an important human pathogen in the presence of hydrogen peroxide stress.
2018-11-13 | GSE114130 | GEO
Project description:Broad-spectrum antibiotics are frequently administered prophylactically to intensive care unit patients as part of empiric care. This treatment has been associated with subsequent infections by the emerging nosocomial pathogen Acinetobacter baumannii; however, the mechanisms underlying this association remain unclear. Here, we demonstrate in a murine model that prophylactic broad-spectrum antibiotic administration drives susceptibility to intranasal infections with A. baumannii, and that reconstitution of the intestinal microbiota by fecal microbiota transplant restores control of infection, implicating microbiota dysbiosis as a key driver of pulmonary disease. Using single-cell RNA sequencing, we determine that prophylaxis suppresses phagocyte effector functions in the lung, including nutritional immunity pathways that restrict pathogen access to essential nutrient metals. Depletion studies identify neutrophils and inflammatory monocytes as central mediators of microbiota-dependent protection, and infection of mice lacking nutritional immunity components lipocalin-2 or calprotectin abrogates the effects of prophylaxis, establishing a causal linkage between microbiota dysbiosis and impaired phagocyte-mediated nutritional immunity. Together, these findings provide a mechanism for the increased severity of A. baumannii pneumonia following antibiotic exposure and highlight the intestinal microbiota as a potential therapeutic target to prevent future nosocomial infections with this and other healthcare-associated pathogens.
2026-04-06 | GSE313334 | GEO
Project description:The long-term resistance to desiccation on abiotic surfaces is a key determinant of the adaptive success of Acinetobacter baumannii as a healthcare-associated bacterial pathogen. Here, the cellular and molecular mechanisms enabling A. baumannii to resist desiccation and persist on abiotic surfaces were investigated. Experiments were set up to mimic the A. baumannii response to air-drying that would occur when bacterial cells contaminate fomites in hospitals. Resistance to desiccation and transition to the “viable but nonculturable” (VBNC) state were determined in the laboratory-adapted strain ATCC 19606T and the epidemic strain ACICU. Culturability, membrane integrity, metabolic activity, virulence, and gene expression profile were compared between the two strains at different stages of desiccation. Upon desiccation, ATCC 19606T and ACICU cells lose culturability and membrane integrity, lower their metabolism, and enter the VBNC state. However, desiccated A. baumannii cells fully recover culturability and virulence in an insect infection model following rehydration in physiological buffers or human biological fluids. Transcriptome and chemical analyses of A. baumannii cells during desiccation unveiled the production of protective metabolites (L-cysteine and L-glutamate) and decreased energetic metabolism consequent to activation of the glyoxylate shunt (GS) pathway, as confirmed by reduced resuscitation efficiency of aceA mutants, lacking the key enzyme of the GS pathway. VBNC cell formation and extensive metabolic reprogramming provide a biological basis for the response of A. baumannii to desiccation, with implications on environmental control measures aimed at preventing the transmission of A. baumannii infection in hospitals.
2024-09-23 | GSE249021 | GEO
Project description:Acinetobacter baumannii poses a substantial global health threat, causing severe multi-drug-resistant infections in hospitalized patients. Circulating clinical isolates present remarkable diversity, with a proportion capable of establishing a transient intracellular niche suitable for persistence, multiplication, and spread. Yet, it remains unknown which bacterial factors mediate the formation and maintenance of this niche, especially within non-phagocytic cells, nor what host responses are elicited. This work demonstrates that the invasive A. baumannii ABC141 strain does not secrete ammonia in endothelial cells as previously shown for other A. baumannii strains multiplying within macrophages but resides in an acidic vacuole devoid of active lysosomal degradative enzymes. Using a Dual-RNAseq approach, we mapped the host and bacterial gene expression during the replicative stage of the infection. An atypical hypoxia cell response was observed without significant induction of the HIF1 pathway, with no metabolic shift or disturbance of mitochondria. Surprisingly, ABC141 efficiently grew in hypoxic conditions in culture and within host cells. In addition, we found a bacterial signature reflective of an adaptation to a nutrient-deprived environment. Our work also highlights a differential role for ABC141 secretion systems, with the T1SS assisting intracellular multiplication and the T2SS required for host cell invasion, implicating for the first time the T2SS in the intracellular lifecycle of invasive ABC141 in endothelial cells.
2025-06-04 | GSE299021 | GEO
Project description:Opportunistic pathogen Acinetobacter baumannii possesses stress tolerance strategies against host innate immunity and antibiotic killing. However, how the host-pathogen-antibiotic interaction affects the overall molecular regulation of pro- and anti-pathogenic machineries remains unexplored. Here, we simultaneously investigate proteomic changes in A. baumannii and macrophages following infection in the absence or presence of the last-line polymyxins. We discover that macrophages and polymyxins exhibit complementary effects to disarm several A. baumannii stress tolerance and survival strategies, including oxidative stress resistance, copper tolerance, bacterial iron acquisition and stringent response regulation systems. Using bacterial mutants with impaired stringent response associated (p)ppGpp synthetase/hydrolase spoT we demonstrate that spot mutants exhibit significantly enhanced susceptibility to polymyxin killing and reduced in vivo survivability compared to the wild-type strain. Together, our findings highlight that improved understanding of host-pathogen-antibiotic interplay is critical for optimisation of antibiotic use in patients and discovery of new antibiotics to tackle multidrug-resistant bacterial infections.
2022-02-11 | PXD028502 | Pride
Project description:Acinetobacter baumannii is an emerging nosocomial pathogen that causes severe infections such as pneumonia or blood stream infections. As the incidence of multidrug-resistant A. baumannii infections in intensive care units increases, the pathogen is considered of greater clinical concern. Little is known about the molecular interaction of A. baumannii with its host yet. In order to study the host cell response upon A. baumannii infection, a complexome analysis was performed. For this, we identified a virulent ( A. baumannii 2778) and a non virulent (A. baumannii 1372) clinical isolate of genetic similarity > 95 % (both isolates from IC 2 harboring OXA 23). HUVECs were infected with each strain and enriched mitochondrial fraction was used for complexome profiling. Complexome analysis identified dramatic reduction of mitochondrial protein complexes in the strain of greater virulence.
2023-04-10 | PXD035235 | Pride
Project description:Typically viral infections make the host more susceptible to subsequent bacterial infections by mechanisms that are incompletely defined. To identify host changes that occur in response to HK68 infection, gene expression of A549 lung epithelial cells were identified. Changes included an increase in transcripts encoding proteins with fibronectin-type III (FnIII) domains, such as fibronectin (Fn), tenascin N (TNN), and tenascin C (TNC). Results provide insight on the host response to IAV infection, including the production of a variety of ECM proteins, which can create an environment rich in host ligands for bacteria adherence
2018-12-25 | GSE112215 | GEO
Project description:Carbapenem-resistant Acinetobacter baumannii (CRAB) is a recognized nosocomial pathogen with limited therapeutics options. Lactic acid bacteria (LAB) constitute a promising therapeutic alternative. Here we aimed to study the antibacterial properties of a collection of LAB strains using phenotypic and transcriptomic analysis against A. baumannii clinical strains. One strain, Lacticaseibacillus rhamnosus CRL 2244, exerts a strong inhibitory capacity on A. baumannii with a strong killing activity. Scanning electron microscopy images showed changes in the morphology of A. baumannii with an increase formation of outer membrane vesicles. Significant changes in the expression levels a wide variety of genes were observed. Interestingly, most of the modified genes were involved in metabolic pathway known to be associated with bacterial survival. The paa operon, Hut system, and fatty acid degradation were some of the pathways that have been induced. The data reveals the impact of Lcb. rhamnosus CRL 2244 on A. baumannii response, resulting in bacterial stress and subsequent cell death. These findings highlight the antibacterial properties of Lcb. rhamnosus CRL 2244 and its potential as an alternative or complementary strategy for treating infections. Further exploration and development of this LAB as a treatment option could provide valuable alternatives for combating CRAB infections.
2023-09-14 | GSE236782 | GEO
Project description:Epithelial cells are the first line of defense within the lung. Disruption of the epithelial barrier by pathogens enables the systematic dissemination of bacteria or viruses within the host, leading to severe diseases with fatal outcomes. Thus, the lung epithelium can be damaged by seasonal and pandemic influenza A viruses. Influenza A virus infection induced dysregulation of the immune system is beneficial for the dissemination of bacteria to the lower respiratory tract, causing bacterial and viral co-infection. Host cells regulate protein homeostasis and the response to different stimuli, for instance pathogen infections, by post translational modification of proteins. Aside from protein phosphorylation, ubiquitination of proteins is an essential regulatory tool in virtually every cellular process, such as protein homeostasis, the host immune response, cell morphology, and in clearing of cytosolic pathogens. Here, we analyzed the proteome and ubiquitinome of A549 cells in response to Streptococcus pneumoniae D39 Δcps and influenza A virus H1N1 as well as bacterial and viral co-infection. Pneumococcal infection induced alterations in the ubiquitination of proteins involved in the organization of the actin cytoskeleton and Rho GTPases, but had minor effects on the abundance of host proteins. H1N1 infection is reflected by an anti-viral state of A549 cells. Finally, co infection resembled the imprints of both infecting pathogens with a minor increase in the observed alterations in protein and ubiquitination abundance.
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