scholarly journals Salmonella Outer Membrane Vesicles contain tRNA Fragments (tRFs) that Inhibit Bacteriophage P22 infection

2021 ◽  
Author(s):  
Dominika Houserova ◽  
Yulong Huang ◽  
Mohan V. Kasukurthi ◽  
Brianna C. Watters ◽  
Fiza F. Khan ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Dependent Manner ◽  
Rna Seq ◽  
Bacteriophage P22 ◽  
Bacteriophage Infection ◽  
Serovar Typhimurium ◽  
Dose Dependent

Salmonella Outer Membrane Vesicles (OMVs) were recently shown to inhibit P22 bacteriophage infection. Furthermore, despite there being several published reports now independently describing (1) the marked prevalence of tRFs within secreted vesicle transcriptomes and (2) roles for specific tRFs in facilitating/inhibiting viral replication, there have been no examinations of the effects of vesicle-secreted tRFs on viral infection reported to date. Notably, while specific tRFs have been reported in a number of bacteria, the tRFs expressed by salmonellae have not been previously characterized. As such, we recently screened small RNA-seq datasets for the presence of recurrent, specifically excised tRFs and identified 31 recurrent, relatively abundant tRFs expressed by Salmonella enterica serovar Typhimurium (SL1344). Furthermore, we find S. Typhimurium OMVs contain significant levels of tRFs highly complementary to known Salmonella enterica-infecting bacteriophage with 17 of 31 tRFs bearing marked complementarity to at least one known Salmonella enterica-infecting phage (averaging 97.4% complementarity over 22.9 nt). Most notably, tRNA-Thr-CGT-1-1, 44-73, bears 100% sequence complementary over its entire 30 nt length to 29 distinct, annotated Salmonella enterica-infecting bacteriophage including P22. Importantly, we find inhibiting this tRF in secreted OMVs improves P22 infectivity in a dose dependent manner whereas raising OMV tRF levels conversely inhibits P22 infectivity. Furthermore, we find P22 phage pre-incubation with OMVs isolated from naive, control SL1344 S. Typhimurium, successfully rescues the ability of S. Typhimurium transformed with a specific tRNA-Thr-CGT-1-1, 44-73 tRF inhibitor to defend against P22. Collectively, these experiments confirm tRFs secreted in S. Typhimurium OMVs are directly involved with and required for the ability of OMVs to defend against bacteriophage predation. As we find the majority of OMV tRFs are highly complementary to an array of known Salmonella enterica-infecting bacteriophage, we suggest OMV tRFs may primarily function as a broadly acting, previously uncharacterized innate antiviral defense.

scholarly journals Salmonella Outer Membrane Vesicles contain tRNA Fragments (tRFs) that Inhibit Bacteriophage P22 infection

2021 ◽  
Author(s):  
Dominika Houserova ◽  
Yulong Huang ◽  
Kasukurthi Kasukurthi ◽  
Brianna Watters ◽  
Fiza Khan ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Dependent Manner ◽  
Antiviral Defense ◽  
Bacteriophage P22 ◽  
Bacteriophage Infection ◽  
Serovar Typhimurium ◽  
Dose Dependent

Abstract Salmonella Outer Membrane Vesicles (OMVs) were recently shown to inhibit P22 bacteriophage infection. Interestingly, we identify 31 recurrent tRFs abundantly expressed by Salmonella enterica serovar Typhimurium and find these tRFs are highly complementary to known Salmonella enterica-infecting bacteriophage (17 averaging 97.4% complementarity over 22.9 nt) and specifically enriched in S. Typhimurium OMVs. Most notably, tRNA-Thr-CGT-1-1, 44-73, bears 100% complementary over its entire 30 nt length to 29 distinct Salmonella enterica-infecting bacteriophage including P22. Importantly, we find inhibiting this tRF in secreted OMVs improves P22 infectivity in a dose dependent manner whereas raising OMV tRF levels conversely inhibits P22. Furthermore, we find P22 pre-incubation with OMVs isolated from naïve S. Typhimurium, rescues the ability of S. Typhimurium depleted of tRNA-Thr-CGT-1-1, 44-73 tRF to defend against P22. Collectively, these experiments confirm tRFs secreted in S. Typhimurium OMVs are directly involved with and required for the ability of OMVs to defend against bacteriophage predation. As we find the majority of OMV tRFs are highly complementary to an array of known Salmonella enterica-infecting bacteriophage, we suggest OMV tRFs may primarily function as a broadly acting, previously uncharacterized ancient antiviral defense.

scholarly journals Display of Recombinant Proteins on Bacterial Outer Membrane Vesicles by Using Protein Ligation

2018 ◽  
Vol 84 (8) ◽  
pp. e02567-17 ◽  
Author(s):  
H. Bart van den Berg van Saparoea ◽  
Diane Houben ◽  
Marien I. de Jonge ◽  
Wouter S. P. Jong ◽  
Joen Luirink
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Salmonella Enterica ◽  
Membrane Vesicles ◽  
Therapeutic Agents ◽  
Outer Membrane Vesicles ◽  
High Density ◽  
Content Type ◽  
Protein Ligation ◽  
Serovar Typhimurium

ABSTRACT The Escherichia coli virulence factor hemoglobin protease (Hbp) has been engineered into a surface display system that can be expressed to high density on live E. coli and Salmonella enterica serovar Typhimurium cells or derived outer membrane vesicles (OMVs). Multiple antigenic sequences can be genetically fused into the Hbp core structure for optimal exposure to the immune system. Although the Hbp display platform is relatively tolerant, increasing the number, size, and complexity of integrated sequences generally lowers the expression of the fused constructs and limits the density of display. This is due to the intricate mechanism of Hbp secretion across the outer membrane and the efficient quality control of translocation-incompetent chimeric Hbp molecules in the periplasm. To address this shortcoming, we explored the coupling of purified proteins to the Hbp carrier after its translocation across the outer membrane using the recently developed SpyTag/SpyCatcher protein ligation system. As expected, fusion of the small SpyTag to Hbp did not hamper display on OMVs. Subsequent addition of purified proteins fused to the SpyCatcher domain resulted in efficient covalent coupling to Hbp-SpyTag. Using in addition the orthogonal SnoopTag/SnoopCatcher system, multiple antigen modules could be coupled to Hbp in a sequential ligation strategy. Not only antigens proved suitable for Spy-mediated ligation but also nanobodies. Addition of this functionality to the platform might allow the targeting of live bacterial or OMV vaccines to certain tissues or immune cells to tailor immune responses.IMPORTANCE Outer membrane vesicles (OMVs) derived from Gram-negative bacteria attract increasing interest in the development of vaccines and therapeutic agents. We aim to construct a semisynthetic OMV platform for recombinant antigen presentation on OMVs derived from attenuated Salmonella enterica serovar Typhimurium cells displaying an adapted Escherichia coli autotransporter, Hbp, at the surface. Although this autotransporter accepts substantial modifications, its capacity with respect to the number, size, and structural complexity of the antigens genetically fused to the Hbp carrier is restricted. Here we describe the application of SpyCatcher/SpyTag protein ligation technology to enzymatically link antigens to Hbp present at high density in OMVs. Protein ligation was apparently unobstructed by the membrane environment and allowed a high surface density of coupled antigens, a property we have shown to be important for vaccine efficacy. The OMV coupling procedure appears versatile and robust, allowing fast production of experimental vaccines and therapeutic agents through a modular plug-and-display procedure.

scholarly journals Reducing Mortality in Salmonella enterica Serovar Typhimurium-Infected Mice with a Tripeptidic Serum Fraction

2002 ◽  
Vol 46 (6) ◽  
pp. 1971-1973 ◽  
Author(s):  
Todd A. Parker ◽  
Kenneth O. Willeford ◽  
Suzanne Parker ◽  
Karyl Buddington
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Dependent Manner ◽  
Serovar Typhimurium ◽  
Dose Dependent

ABSTRACT Salmonellosis-induced mortality in female Swiss Webster mice decreased significantly when tripeptidic immunostimulant (TPI) was administered prophylactically. Prophylactic benefits developed in a dose-dependent manner wherein 15 mg of TPI given 1 day before challenge reduced mortality by 70%.

scholarly journals Naturally Occurring IgG Antibodies Provide Innate Protection against Vibrio cholerae Bacteremia by Recognition of the Outer Membrane Protein U

2016 ◽  
Vol 8 (3) ◽  
pp. 269-283 ◽  
Author(s):  
Kyaw Min Aung ◽  
Annika E. Sjöström ◽  
Ulrich von Pawel-Rammingen ◽  
Kristian Riesbeck ◽  
Bernt Eric Uhlin ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Outer Membrane Protein ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Immune Defense ◽  
Dependent Manner ◽  
Naturally Occurring ◽  
Serum Killing

Cholera epidemics are caused by Vibrio cholerae serogroups O1 and O139, whereas strains collectively known as non-O1/non-O139 V. cholerae are found in cases of extraintestinal infections and bacteremia. The mechanisms and factors influencing the occurrence of bacteremia and survival of V. cholerae in normal human serum have remained unclear. We found that naturally occurring IgG recognizing V. cholerae outer membrane protein U (OmpU) mediates a serum-killing effect in a complement C1q-dependent manner. Moreover, outer membrane vesicles (OMVs) containing OmpU caused enhanced survival of highly serum-sensitive classical V. cholerae in a dose-dependent manner. OMVs from wild-type and ompU mutant V. cholerae thereby provided a novel means to verify by extracellular transcomplementation the involvement of OmpU. Our data conclusively indicate that loss, or reduced expression, of OmpU imparts resistance to V. cholerae towards serum killing. We propose that the difference in OmpU protein levels is a plausible reason for differences in serum resistance and the ability to cause bacteremia observed among V. cholerae biotypes. Our findings provide a new perspective on how naturally occurring antibodies, perhaps induced by members of the microbiome, may play a role in the recognition of pathogens and the provocation of innate immune defense against bacteremia.

scholarly journals Decoration of Outer Membrane Vesicles with Multiple Antigens by Using an Autotransporter Approach

2014 ◽  
Vol 80 (18) ◽  
pp. 5854-5865 ◽  
Author(s):  
Maria H. Daleke-Schermerhorn ◽  
Tristan Felix ◽  
Zora Soprova ◽  
Corinne M. ten Hagen-Jongman ◽  
David Vikström ◽  
...  
Keyword(s):  
Immune Responses ◽  
Outer Membrane ◽  
Vaccine Development ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Heterologous Proteins ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Heterologous Antigens

ABSTRACTOuter membrane vesicles (OMVs) are spherical nanoparticles that naturally shed from Gram-negative bacteria. They are rich in immunostimulatory proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive vaccine vectors. By packaging foreign polypeptides in OMVs, specific immune responses can be raised toward heterologous antigens in the context of an intrinsic adjuvant. Antigens exposed at the vesicle surface have been suggested to elicit protection superior to that from antigens concealed inside OMVs, but hitherto robust methods for targeting heterologous proteins to the OMV surface have been lacking. We have exploited our previously developed hemoglobin protease (Hbp) autotransporter platform for display of heterologous polypeptides at the OMV surface. One, two, or three of theMycobacterium tuberculosisantigens ESAT6, Ag85B, and Rv2660c were targeted to the surface ofEscherichia coliOMVs upon fusion to Hbp. Furthermore, a hypervesiculating ΔtolRΔtolAderivative of attenuatedSalmonella entericaserovar Typhimurium SL3261 was generated, enabling efficient release and purification of OMVs decorated with multiple heterologous antigens, exemplified by theM. tuberculosisantigens and epitopes fromChlamydia trachomatismajor outer membrane protein (MOMP). Also, we showed that delivery ofSalmonellaOMVs displaying Ag85B to antigen-presenting cellsin vitroresults in processing and presentation of an epitope that is functionally recognized by Ag85B-specific T cell hybridomas. In conclusion, the Hbp platform mediates efficient display of (multiple) heterologous antigens, individually or combined within one molecule, at the surface of OMVs. Detection of antigen-specific immune responses upon vesicle-mediated delivery demonstrated the potential of our system for vaccine development.

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