Selective packaged circular RNAs in milk extracellular vesicles during Staphylococcus aureus infection may have potential against bacterial infection.
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ABSTRACT:
SUBMITTER: Ma S
PROVIDER: S-EPMC8078504 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:PURPOSE:The microbial environment is an important factor that contributes to the pathogenesis of atopic dermatitis (AD). Recently, it was revealed that not only bacteria itself but also extracellular vesicles (EVs) secreted from bacteria affect the allergic inflammation process. However, almost all research carried out so far was related to local microorganisms, not the systemic microbial distribution. We aimed to compare the bacterial EV composition between AD patients and healthy subjects and to experimentally find out the beneficial effect of some bacterial EV composition. METHODS:Twenty-seven AD patients and 6 healthy control subjects were enrolled. After urine and serum were obtained, EVs were prepared from samples. Metagenomic analysis of 16s ribosomal DNA extracted from the EVs was performed, and bacteria showing the greatest difference between controls and patients were identified. In vitro and in vivo therapeutic effects of significant bacterial EV were evaluated with keratinocytes and with Staphylococcus aureus-induced mouse AD models, respectively. RESULTS:The proportions of Lactococcus, Leuconostoc and Lactobacillus EVs were significantly higher and those of Alicyclobacillus and Propionibacterium were lower in the control group than in the AD patient group. Therefore, lactic acid bacteria were considered to be important ones that contribute to the difference between the patient and control groups. In vitro, interleukin (IL)-6 from keratinocytes and macrophages decreased and cell viability was restored with Lactobacillus plantarum-derived EV treatment prior to S. aureus EV treatment. In S. aureus-induced mouse AD models, L. plantarum-derived EV administration reduced epidermal thickening and the IL-4 level. CONCLUSIONS:We suggested the protective role of lactic acid bacteria in AD based on metagenomic analysis. Experimental findings further suggest that L. plantarum-derived EV could help prevent skin inflammation.
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Project description:The prevalence of Staphylococcus aureus worldwide as a nosocomial infectious agent is recognized but the reason behind the spread of this bacterium has remained elusive. Here, we hypothesized that the communication of S. aureus might benefit from it blocking other bacteria from establishing themselves on the surface. This was found to be the case for several pathogens as the S. aureus supernatant curtailed their ability to form biofilms. Subsequent analyses using Acinetobacter baumannii as a model found this effect is primarily mediated by S. aureus' extracellular vesicles (EVs), which bound to the polystyrene surface. We found the EV-treated surfaces were significantly more hydrophilic after EV treatment, a condition that made it difficult for A. baumannii to initially adhere to the polystyrene surface and reduced its resulting biofilm by up to 93%. Subsequent tests found this also extended to several other bacterial pathogens, with a 40-70% decrease in their biofilm mass. The S. aureus EVs and their activity still remained after the surface was washed with 10% bleach, while the use of ethylenediaminetetraacetic acid (EDTA) removed both the EVs from the surface and their activity.
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Project description:Breast cancer is the second cause of cancer-associated death among women and seriously endangers women's health. Therefore, early identification of breast cancer would be beneficial to women's health. At present, circular RNA (circRNA) not only exists in the extracellular vesicles (EVs) in plasma, but also presents distinct patterns under different physiological and pathological conditions. Therefore, we assume that circRNA could be used for early diagnosis of breast cancer. Here, we developed classifiers for breast cancer diagnosis that relied on 259 samples, including 144 breast cancer patients and 115 controls. In the discovery stage, we compared the genome-wide long RNA profiles of EVs in patients with breast cancer (n=14) and benign breast (n=6). To further verify its potential in early diagnosis of breast cancer, we prospectively collected plasma samples from 259 individuals before treatment, including 144 breast cancer patients and 115 controls. Finally, we developed and verified the predictive classifies based on their circRNA expression profiles of plasma EVs by using multiple machine learning models. By comparing their circRNA profiles, we found 439 circRNAs with significantly different levels between cancer patients and controls. Considering the cost and practicability of the test, we selected 20 candidate circRNAs with elevated levels and detected their levels by quantitative real-time polymerase chain reaction. In the training cohort, we found that BCExoC, a nine-circRNA combined classifier with SVM model, achieved the largest AUC of 0.83 [95% CI 0.77-0.88]. In the validation cohort, the predictive efficacy of the classifier achieved 0.80 [0.71-0.89]. Our work reveals the application prospect of circRNAs in plasma EVs as non-invasive liquid biopsies in the diagnosis and management of breast cancer.
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Project description:Backspliced circular RNAs (circRNAs) are prevalent in many eukaryotic systems and are spliced from thousands of different genes. Where examined, circRNAs are often highly stable and the mechanisms by which cells degrade and/or clear circRNAs from the cells are unknown. Here we investigated the possibility that cells can eliminate circRNAs into extracellular space, possibly within released vesicles such as exosomes and microvesicles. From three different cell lines and examining multiple circRNAs, we show that extracellular vesicle (EVs) preparations recovered from cell culture conditioned media contain established circRNAs. Moreover, these circRNAs are enriched over their linear counterparts within EV preparations when compared to the producing cells. This supports the idea that expulsion from cells into extracellular space, as by EVs release, can be a mechanism by which cells clear circRNAs. Moreover, since EVs can be taken up by other cells, excreted circRNAs could contribute to cell to cell communication.
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Project description:Staphylococcus aureus is a pathogenic bacterium but also a commensal of skin and anterior nares in humans. As S. aureus transits from skins/nares to inside the human body, it experiences changes in temperature. The production and content of S. aureus extracellular vesicles (EVs) have been increasingly studied over the past few years, and EVs are increasingly being recognized as important to the infectious process. Nonetheless, the impact of temperature variation on S. aureus EVs has not been studied in detail, as most reports that investigate EV cargoes and host cell interactions are performed using vesicles produced at 37°C. Here, we report that EVs in S. aureus differ in size and protein/RNA cargo depending on the growth temperature used. We demonstrate that the temperature-dependent regulation of vesicle production in S. aureus is mediated by the alpha phenol-soluble modulin peptides (αPSMs). Through proteomic analysis, we observed increased packaging of virulence factors at 40°C, whereas the EV proteome has greater diversity at 34°C. Similar to the protein content, we perform transcriptomic analysis and demonstrate that the RNA cargo also is impacted by temperature. Finally, we demonstrate greater αPSM- and alpha-toxin-mediated erythrocyte lysis with 40°C EVs, but 34°C EVs are more cytotoxic toward THP-1 cells. Together, our study demonstrates that small temperature variations have great impact on EV biogenesis and shape the interaction with host cells. IMPORTANCE Extracellular vesicles (EVs) are lipid bilayer spheres that contain proteins, nucleic acids, and lipids secreted by bacteria. They are involved in Staphylococcus aureus infections, as they package virulence factors and deliver their contents inside host cells. The impact of temperature variations experienced by S. aureus during the infectious process on EVs is unknown. Here, we demonstrate the importance of temperature in vesicle production and packaging. High temperatures promote packaging of virulence factors and increase the protein and lipid concentration but reduce the overall RNA abundance and protein diversity in EVs. The importance of temperature changes is highlighted by the fact that EVs produced at low temperature are more toxic toward macrophages, whereas EVs produced at high temperature display more hemolysis toward erythrocytes. Our research brings new insights into temperature-dependent vesiculation and interaction with the host during S. aureus transition from colonization to virulence.
| S-EPMC8510519 | biostudies-literature
Project description:Staphylococcal aureus (S. aureus), a Gram-positive bacteria, is known to cause various infections. Extracellular vesicles (EVs) are a heterogeneous array of membranous structures secreted by cells from all three domains of life, i.e., eukaryotes, bacteria, and archaea. Bacterial EVs are implied to be involved in both bacteria-bacteria and bacteria-host interactions during infections. It is still unclear how S. aureus EVs interact with host cells and induce inflammatory responses. In this study, EVs were isolated from S. aureus and mutant strains deficient in either prelipoprotein lipidation (Δlgt) or major surface proteins (ΔsrtAB). Their immunostimulatory capacities were assessed both in vitro and in vivo. We found that S. aureus EVs induced pro-inflammatory responses both in vitro and in vivo. However, this activity was dependent on lipidated lipoproteins (Lpp), since EVs isolated from the Δlgt showed no stimulation. On the other hand, EVs isolated from the ΔsrtAB mutant showed full immune stimulation, indicating the cell wall anchoring of surface proteins did not play a role in immune stimulation. The immune stimulation of S. aureus EVs was mediated mainly by monocytes/macrophages and was TLR2 dependent. In this study, we demonstrated that not only free Lpp but also EV-imbedded Lpp had high pro-inflammatory activity.
| S-EPMC8268867 | biostudies-literature
Project description:Staphylococcus aureus generates and releases extracellular vesicles (EVs) that package cytosolic, cell-wall associated, and membrane proteins, as well as glycopolymers and exoproteins, including alpha hemolysin, leukocidins, phenol-soluble modulins, superantigens, and enzymes. S. aureus EVs, but not EVs from pore-forming toxin-deficient strains, were cytolytic for a variety of mammalian cell types, but EV internalization was not essential for cytotoxicity. Because S. aureus is subject to various environmental stresses during its encounters with the host during infection, we assessed how these exposures affected EV production in vitro. Staphylococci grown at 37 °C or 40 °C did not differ in EV production, but cultures incubated at 30 °C yielded more EVs when grown to the same optical density.S. aureus cultivated in the presence of oxidative stress, in iron-limited media, or with subinhibitory concentrations of ethanol, showed greater EV production as determined by protein yield and quantitative immunoblots. In contrast, hyperosmotic stress or subinhibitory concentrations of erythromycin reduced S. aureus EV yield. EVs represent a novel S. aureus secretory system that is affected by a variety of stress responses and allows the delivery of biologically active pore-forming toxins and other virulence determinants to host cells.
| S-EPMC7909408 | biostudies-literature
Project description:Secretion of extracellular vesicles (EVs), a process common to eukaryotes, archae, and bacteria, represents a secretory pathway that allows cell-free intercellular communication. Microbial EVs package diverse proteins and influence the host-pathogen interaction, but the mechanisms underlying EV production in Gram-positive bacteria are poorly understood. Here we show that EVs purified from community-associated methicillin-resistant Staphylococcus aureus package cytosolic, surface, and secreted proteins, including cytolysins. Staphylococcal alpha-type phenol-soluble modulins promote EV biogenesis by disrupting the cytoplasmic membrane; whereas, peptidoglycan cross-linking and autolysin activity modulate EV production by altering the permeability of the cell wall. We demonstrate that EVs purified from a S. aureus mutant that is genetically engineered to express detoxified cytolysins are immunogenic in mice, elicit cytolysin-neutralizing antibodies, and protect the animals in a lethal sepsis model. Our study reveals mechanisms underlying S. aureus EV production and highlights the usefulness of EVs as a S. aureus vaccine platform.
| S-EPMC5895597 | biostudies-literature
Project description:The roles of bacterial extracellular vesicles (EVs) in cell-to-cell signaling are progressively being unraveled. These membranous spheres released by many living cells carry various macromolecules, some of which influence host-pathogen interactions. Bacterial EVs contain RNA, which may serve in communicating with their infected hosts. Staphylococcus aureus, an opportunistic human and animal pathogen, produces EVs whose RNA content is still poorly characterized. Here, we investigated in depth the RNA content of S. aureus EVs. A high-throughput RNA sequencing approach identified RNAs in EVs produced by the clinical S. aureus strain HG003 under different environmental conditions: early- and late-stationary growth phases, and presence or absence of a sublethal vancomycin concentration. On average, sequences corresponding to 78.0% of the annotated transcripts in HG003 genome were identified in HG003 EVs. However, only ~5% of them were highly covered by reads (≥90% coverage) indicating that a large fraction of EV RNAs, notably mRNAs and sRNAs, were fragmented in EVs. According to growth conditions, from 86 to 273 highly covered RNAs were identified into the EVs. They corresponded to 286 unique RNAs, including 220 mRNAs. They coded for numerous virulence-associated factors (hld encoded by the multifunctional sRNA RNAIII, agrBCD, psmβ1, sbi, spa, and isaB), ribosomal proteins, transcriptional regulators, and metabolic enzymes. Twenty-eight sRNAs were also detected, including bona fide RsaC. The presence of 22 RNAs within HG003 EVs was confirmed by reverse transcription quantitative PCR (RT-qPCR) experiments. Several of these 286 RNAs were shown to belong to the same transcriptional units in S. aureus. Both nature and abundance of the EV RNAs were dramatically affected depending on the growth phase and the presence of vancomycin, whereas much less variations were found in the pool of cellular RNAs of the parent cells. Moreover, the RNA abundance pattern differed between EVs and EV-producing cells according to the growth conditions. Altogether, our findings show that the environment shapes the RNA cargo of the S. aureus EVs. Although the composition of EVs is impacted by the physiological state of the producing cells, our findings suggest a selective packaging of RNAs into EVs, as proposed for EV protein cargo. Our study shedds light to the possible roles of potentially functional RNAs in S. aureus EVs, notably in host-pathogen interactions.
| S-EPMC7990786 | biostudies-literature
Project description:Staphylococcus aureus is a pathogenic bacterium but also a commensal of skin and anterior nares in humans. As S. aureus transits from skins/nares to inside the human body, it experiences changes in temperature. The production and content of S. aureus extracellular vesicles (EV) have been increasingly studied over the past few years and EVs are increasingly being recognized as important to the infectious process. Nonetheless, the impact of temperature variation on S. aureus EVs has not been studied in detail as most reports that investigate EV cargoes and host cell interactions are performed using vesicles produced at 37˚C. Here we report that S. aureus vesicle production is temperature-dependent with greater vesiculation at 40˚C. We demonstrate that the temperature dependent regulation of vesicle production in S. aureus is mediated by the alpha phenol soluble modulin peptides (αPSMs). Through proteomic analysis, we observed increased packaging of virulence factors at 40˚C whereas more total proteins are present in EVs produced at 34˚C. Similar to the protein content, we perform transcriptomic analysis and demonstrate that the RNA cargo is impacted by temperature also. Finally, we demonstrate greater αPSM- and α-toxin mediated erythrocyte lysis with 40˚C EVs but 34˚C EVs are more cytotoxic toward THP-1 cells. Together our study demonstrates that small temperature variations have great impact on EV biogenesis and shape the interaction with host cells.
2021-09-17 | GSE171489 | GEO