Temperature influences the composition and cytotoxicity of extracellular vesicles in Staphylococcus aureus
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ABSTRACT: 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.
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.
Project description:Staphylococcus aureus is an opportunistic pathogen that colonizes the anterior nares of about 30-50% of the population. Colonization is most often asymptomatic, however, self-inoculation through inhalation, ingestion, or an open wound, can give rise to potentially fatal infections of the deeper tissues and blood. Like all bacteria, S. aureus is able to sense and respond to environmental cues and modify gene expression to adapt to specific environmental conditions. The transition of S. aureus from the nares to the deeper tissues and blood is accompanied by a number of changes in environmental conditions, such as nutrient availability, pH, and temperature. On average, the human anterior nares are 34 ˚C while a healthy individual maintains a core body temperature of 37 ˚C. In this study we investigate the response of S. aureus to changing temperature. Transcriptomics and proteomics were performed on S. aureus cultures growing at three physiologically relevant temperatures, 34˚C (nares), 37˚C (body), and 40˚C (pyrexia), to determine if small scale, biologically meaningful alterations in temperature have an impact on S. aureus gene expression. Results show that small but definite temperature changes elicit a large-scale restructuring of the S. aureus transcriptome and proteome. We demonstrate that these changes have physiological relevance through phenotypic analyses. Finally, using a human epithelial cell line infection assay, we investigate the impact that temperature dependent alterations in gene expression have on S. aureus pathogenesis and demonstrate decreased intracellular invasion of S. aureus cells grown at 34˚C. Collectively, our results demonstrate that small but biologically meaningful alterations in temperature can influence on S. aureus gene expression and may be a major contributor to the transition from a commensal to pathogen.
Project description:Staphylococcus aureus is an opportunistic pathogen that colonizes the anterior nares of 30-50% of the population. Colonization is most often asymptomatic, however, self-inoculation can give rise to potentially fatal infections of the deeper tissues and blood. Like all bacteria, S. aureus is able to sense and respond to environmental cues and modify gene expression to adapt to specific environmental conditions. The transition of S. aureus from the nares to the deeper tissues and blood is accompanied by changes in environmental conditions, such as nutrient availability, pH, and temperature. On average, the human anterior nares are 34°C while a healthy individual maintains a core body temperature of 37°C. In this study we investigate the response of S. aureus to changing temperature. Transcriptomics and proteomics were performed on S. aureus cultures growing at three physiologically relevant temperatures, 34°C (nares), 37°C (body), and 40°C (pyrexia), to determine if small scale, biologically meaningful alterations in temperature have an impact on S. aureus gene expression. Results show that small but definite temperature changes elicit a large-scale restructuring of the S. aureus transcriptome and proteome. We demonstrate that these changes have physiological relevance through phenotypic analyses. Finally, we investigate the impact of temperature dependent alterations in gene expression on S. aureus pathogenesis and demonstrate decreased intracellular invasion of S. aureus grown at 34°C. Collectively, our results demonstrate that small but biologically meaningful alterations in temperature influence S. aureus gene expression, a process that is likely a major contributor to the transition from a commensal to pathogen.
Project description:Oncogenes reprogram multiple metabolic phenotypes of cancer cells including the balance between anabolic and catabolic processes, mechanisms of nutrient uptake, and choices in nutrient utilization. Here, we explore how different oncogenes regulate biomass loss via extracellular vesicle release. We use isogenic mammary breast epithelial cells transformed with a panel of oncogenes found commonly mutated, amplified or overexpressed in multiple cancers. We observe an increase in extracellular vesicle (EV) release upon oncogenic transformation, with MYC and AURKB oncogenes eliciting the highest number of EVs produced. Oncogene expression altered the protein composition of released EVs. Likewise, miRNAs were differentially sorted into EVs in an oncogene-specific manner. We performed an integrated pathway analysis of metabolites and gene expression across different oncogene-expressing cells and identified that ceramide-sphingosine metabolism was broadly deregulated, especially in MYC overexpressing cells. Inhibition of neutral sphingomyelinases (N-SMase) resulted in significant decrease in EV production in MYC high cells, while ESCRT-dependent small EV production predominated in AURKB cells.
Project description:Beyond forming bone, osteoblasts play pivotal roles in various biological processes, including hematopoiesis and bone metastasis. Extracellular vesicles (EVs) have recently been implicated in intercellular communication via transfer of proteins and nucleic acids between cells. Here, we focused on the proteomic characterization of non-mineralizing (NMOBs) and mineralizing (MOBs) human osteoblast (SV-HFOs) EVs and investigated their effect on human prostate cancer (PC3) cells by microscopic, proteomic and gene expression analyses. Proteomic analysis showed that 97% of the proteins were shared among NMOB and MOB EVs, and 30% were novel osteoblast-specific EV proteins. Label-free quantification demonstrated mineralization stage-dependent five-fold enrichment of 59 and 451 EV proteins in NMOBs and MOBs, respectively. Interestingly, bioinformatic analyses of the osteoblast EV proteomes and EV-regulated prostate cancer gene expression profiles showed that they converged on pathways involved in cell survival and growth. This was verified by in vitro proliferation assays where osteoblast EV uptake led to two-fold increase in PC3 cell growth compared to cell-free culture medium-derived vesicle controls. Our findings elucidate the mineralization stage-specific protein content of osteoblast-secreted EVs, show a novel way by which osteoblasts communicate with prostate cancer, and open up innovative avenues for therapeutic intervention. PC3 cells were treated with extracellular vesicles from non-mineralizing and mineralizing SV-HFOs for three different incubation times (4hrs, 24hrs, 48hr)
Project description:Extracellular vesicles (EVs) are nanosized cell-derived vesicles found in all bodily fluids which provide a route of intercellular communication by transmitting biological cargo. While EVs offer promise as therapeutic agents, the molecular mechanisms of EV biogenesis are not yet fully elucidated, in part due to the concurrence of numerous interwoven pathways which give rise to heterogenous EV populations in vitro. The effects of conditions in the cellular environment on EV production are of particular interest. In this study, we utilize a quantifiable EV-engineering approach to investigate how various cell media conditions alter EV production. The presence of serum, exogenous EVs, and other signaling factors in cell media alters EV production on physical, molecular, and transcriptional levels. Further, we demonstrate that exosome biogenesis pathways are the major factors contributing to EV production under optimized conditions. Our findings suggest a novel understanding to the mechanisms underlying EV production in cell culture which can be applied to develop advanced EV production methods.
Project description:With this experiment we sought to characterise the effect of Extracellular Vesicle (EV) mediated transfer of mitochondria from Neural Stem Cells (NSCs) to macrophages. Briefly, macrophages were obtained from the bone marrow of C57BL/6 mice and stimulated with 50 ng/ml LPS. Macrophages were treated with EVs derived from Neural Stem Cells for 6 hours after which RNA was extracted for microarray analysis.
Project description:This project detected the protein composition of extracellular vesicles (EV) produced by S. aureus WT JE2 strain and its lgt mutant (lipoprotein deficient mutant). Our recent study found that mutation of lgt in S. aureus USA300 JE2 strain significantly increased EV production in S. aureus and decreased the pore-forming toxin content of vesicles, indicatiung that lipoproteins modulate the EV biogenesis of S. aureus. To gain a better understanding of this process, we detected the protein compositions associated with EVs purified from both WT and lgt mutant EVs by LC-MS/MS. Compared to WT EVs, more cytosoli proteins and less extracellular proteins were identified in lgt mutant EVs. A total of 180 and 198 proteins were identified from WT and lgt mutant EVs, respectively.In addition 27.2% and 33.8% of identified proteins were unique to WT or lgt mutant EVs respectively.
Project description:Exosomes and microvesicles (i.e., extracellular vesicles; EVs) have been identified within ovarian follicular fluid, and recent evidence suggests that EVs are able to elicit profound effects on ovarian cell function. While existence of miRNA within EVs has been reported, it remains unknown if EV size and concentration as well as their cargos (i.e., proteins and RNA) change during antral follicle growth. Extracellular vesicles isolated from follicular fluid of small, medium and large bovine follicles were similar in size, while concentration of EVs decreased progressively as follicle size increased. Electron microscopy indicated a highly purified population of the lipid bilayer enclosed vesicles that were enriched in exosome biomarkers including CD81 and Alix. Small RNA sequencing identified a large number of known and novel miRNAs that changed in the EVs of different size follicles. Ingenuity Pathway Analysis (IPA) indicated that miRNA abundant in small follicle EV preparations were associated with cell proliferation pathways, while those miRNA abundant in large follicle preparations were related to inflammatory response pathways. These studies are the first to demonstrate that EVs change in their levels and makeup during antral follicle development and point to the potential for a unique vesicle-mediated cell-to-cell communication network within the ovarian follicle. Examination of small RNA population in bovine follicular fluid extracellular vesicles isolated from antral follicles
Project description:In this study, we present the comparative transcriptome analysis of human osteoblasts and their corresponding EVs using next-generation sequencing. We demonstrate that osteoblast-EVs are specifically depleted of cellular mRNAs that encode proteins involved in basic cellular activities, such as cytoskeletal functions, cell survival and apoptosis. In contrast, EVs are significantly enriched with 254 mRNAs that are associated with protein translation and RNA processing. Moreover, mRNAs enriched in EVs encode proteins important for communication with the surrounding cells, in particular with osteoclasts, adipocytes and hematopoietic stem cells. Strikingly, EVs are particularly enriched with RAB13 mRNA, which is linked to vesicular trafficking. The latter suggests that EVs may affect vesicle production in target cells. These findings provide the foundation for understanding the molecular mechanism and function of EV-mediated interactions between osteoblasts and the surrounding bone microenvironment.