Study on RNA Regulating Iron Transport in Outer Membrane Vesicles of Hypervirulent Klebsiella Pneumoniae

Abstract Background: The iron acquisition ability of hypervirulent Klebsiella pneumoniae (hvKP) is an important part of its super virulence mechanism, increasing studies have proved that outer membrane vesicles (OMVs) are involved in the iron acquisition process of bacteria. Thus, we compared the difference in RNA expression in OMVs of hvKP in iron-rich and iron-deficient medium, and explore the possible mechanism of RNA in OMVs involved in hvKP iron acquisition. Results: The results of high-throughput sequencing showed that in iron-deficient medium, there were 239 up-regulated and 89 down-regulated mRNAs in OMVs of hvKP, of which 20 mRNAs related to iron transport was up-regulated, mainly including siderophore synthesis and receptor genes, ATP binding cassette transporter family and iron sulfur cluster. Only two of the differential ncRNAs that regulate these mRNAs are up-regulated, which are lncRNAs.Conclusion: We demonstrated that mRNA and lncRNA in OMVs were directly or indirectly involved in the iron acquisition mechanism of hvKP under iron deficiency environment, which enhanced the adaptive survival ability of hvKP. It provided a basis for further exploring the iron acquisition mechanism of OMVs involved in hvKP.

Download Full-text

Lipidomic Analysis of the Outer Membrane Vesicles from Paired Polymyxin-Susceptible and -Resistant Klebsiella pneumoniae Clinical Isolates

International Journal of Molecular Sciences ◽

10.3390/ijms19082356 ◽

2018 ◽

Vol 19 (8) ◽

pp. 2356 ◽

Cited By ~ 5

Author(s):

Raad Jasim ◽

Mei-Ling Han ◽

Yan Zhu ◽

Xiaohan Hu ◽

Maytham Hussein ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Outer Membrane ◽

Membrane Vesicles ◽

Average Diameter ◽

Polymyxin B ◽

Outer Membrane Vesicles ◽

Resistant Isolate ◽

Average Particle ◽

Lipid Species ◽

The Impact

Gram-negative bacteria produce outer membrane vesicles (OMVs) as delivery vehicles for nefarious bacterial cargo such as virulence factors, which are antibiotic resistance determinants. This study aimed to investigate the impact of polymyxin B treatment on the OMV lipidome from paired polymyxin-susceptible and -resistant Klebsiella pneumoniae isolates. K. pneumoniae ATCC 700721 was employed as a reference strain in addition to two clinical strains, K. pneumoniae FADDI-KP069 and K. pneumoniae BM3. Polymyxin B treatment of the polymyxin-susceptible strains resulted in a marked reduction in the glycerophospholipid, fatty acid, lysoglycerophosphate and sphingolipid content of their OMVs. Conversely, the polymyxin-resistant strains expressed OMVs richer in all of these lipid species, both intrinsically and increasingly under polymyxin treatment. The average diameter of the OMVs derived from the K. pneumoniae ATCC 700721 polymyxin-susceptible isolate, measured by dynamic light scattering measurements, was ~90.6 nm, whereas the average diameter of the OMVs isolated from the paired polymyxin-resistant isolate was ~141 nm. Polymyxin B treatment (2 mg/L) of the K. pneumoniae ATCC 700721 cells resulted in the production of OMVs with a larger average particle size in both the susceptible (average diameter ~124 nm) and resistant (average diameter ~154 nm) strains. In light of the above, we hypothesize that outer membrane remodelling associated with polymyxin resistance in K. pneumoniae may involve fortifying the membrane structure with increased glycerophospholipids, fatty acids, lysoglycerophosphates and sphingolipids. Putatively, these changes serve to make the outer membrane and OMVs more impervious to polymyxin attack.

Download Full-text

Physicochemical Evidence that Francisella FupA and FupB Proteins Are Porins

International Journal of Molecular Sciences ◽

10.3390/ijms21155496 ◽

2020 ◽

Vol 21 (15) ◽

pp. 5496

Author(s):

Claire Siebert ◽

Corinne Mercier ◽

Donald K. Martin ◽

Patricia Renesto ◽

Beatrice Schaack

Keyword(s):

Outer Membrane ◽

Lipid Bilayers ◽

Lipid Membranes ◽

Iron Transport ◽

Molecular Mechanisms ◽

Protein A ◽

Membrane Vesicles ◽

Disodium Salt ◽

Outer Membrane Vesicles ◽

Novel Therapeutic Strategies

Responsible for tularemia, Francisella tularensis bacteria are highly infectious Gram-negative, category A bioterrorism agents. The molecular mechanisms for their virulence and resistance to antibiotics remain largely unknown. FupA (Fer Utilization Protein), a protein mediating high-affinity transport of ferrous iron across the outer membrane, is associated with both. Recent studies demonstrated that fupA deletion contributed to lower F. tularensis susceptibility towards fluoroquinolones, by increasing the production of outer membrane vesicles. Although the paralogous FupB protein lacks such activity, iron transport capacity and a role in membrane stability were reported for the FupA/B chimera, a protein found in some F. tularensis strains, including the live vaccine strain (LVS). To investigate the mode of action of these proteins, we purified recombinant FupA, FupB and FupA/B proteins expressed in Escherichia coli and incorporated them into mixed lipid bilayers. We examined the porin-forming activity of the FupA/B proteoliposomes using a fluorescent 8-aminonaphthalene-1,3,6-trisulfonic acid, disodium salt (ANTS) probe. Using electrophysiology on tethered bilayer lipid membranes, we confirmed that the FupA/B fusion protein exhibits pore-forming activity with large ionic conductance, a property shared with both FupA and FupB. This demonstration opens up new avenues for identifying functional genes, and novel therapeutic strategies against F. tularensis infections.

Download Full-text

A Pseudomonas T6SS effector recruits PQS-containing outer membrane vesicles for iron acquisition

Nature Communications ◽

10.1038/ncomms14888 ◽

2017 ◽

Vol 8 (1) ◽

Cited By ~ 83

Author(s):

Jinshui Lin ◽

Weipeng Zhang ◽

Juanli Cheng ◽

Xu Yang ◽

Kaixiang Zhu ◽

...

Keyword(s):

Outer Membrane ◽

Iron Acquisition ◽

Membrane Vesicles ◽

Outer Membrane Vesicles

Download Full-text

Porin Loss Impacts the Host Inflammatory Response to Outer Membrane Vesicles of Klebsiella pneumoniae

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01627-15 ◽

2015 ◽

Vol 60 (3) ◽

pp. 1360-1369 ◽

Cited By ~ 11

Author(s):

Kelli L. Turner ◽

Bethaney K. Cahill ◽

Sarah K. Dilello ◽

Dedra Gutel ◽

Debra N. Brunson ◽

...

Keyword(s):

Antibiotic Resistance ◽

Klebsiella Pneumoniae ◽

Outer Membrane ◽

Proinflammatory Cytokine ◽

Membrane Vesicles ◽

Outer Membrane Vesicles ◽

Cytokine Secretion ◽

Phagocytic Cells ◽

Altered Expression ◽

Content Type

Antibiotic-resistant strains ofKlebsiella pneumoniaeoften exhibit porin loss. In this study, we investigated how porin loss impacted the composition of secreted outer membrane vesicles as well as their ability to trigger proinflammatory cytokine secretion by macrophages. We hypothesize that porin loss associated with antibiotic resistance will directly impact both the composition of outer membrane vesicles and their interactions with phagocytic cells. Using clonally related clinical isolates of extended-spectrum beta-lactamase (ESBL)-positiveKlebsiella pneumoniaewith different patterns of porin expression, we demonstrated that altered expression of OmpK35 and OmpK36 results in broad alterations to the protein profile of secreted vesicles. Additionally, the level of OmpA incorporation was elevated in strains lacking a single porin. Porin loss significantly impacted macrophage inflammatory responses to purified vesicles. Outer membrane vesicles lacking both OmpK35 and OmpK36 elicited significantly lower levels of proinflammatory cytokine secretion than vesicles from strains expressing one or both porins. These data demonstrate that antibiotic resistance-associated porin loss has a broad and significant effect on both the composition of outer membrane vesicles and their interactions with phagocytic cells, which may impact bacterial survival and inflammatory reactions in the host.

Download Full-text

Isolation, characterization and analysis of pro-inflammatory potential of Klebsiella pneumoniae outer membrane vesicles

Microbial Pathogenesis ◽

10.1016/j.micpath.2019.103719 ◽

2019 ◽

Vol 136 ◽

pp. 103719 ◽

Cited By ~ 1

Author(s):

Francesca Martora ◽

Federica Pinto ◽

Veronica Folliero ◽

Marcella Cammarota ◽

Federica Dell’Annunziata ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Outer Membrane ◽

Membrane Vesicles ◽

Outer Membrane Vesicles

Download Full-text

Nanoparticle reinforced bacterial outer-membrane vesicles effectively prevent fatal infection of carbapenem-resistant Klebsiella pneumoniae

Nanomedicine Nanotechnology Biology and Medicine ◽

10.1016/j.nano.2019.102148 ◽

2020 ◽

Vol 24 ◽

pp. 102148 ◽

Cited By ~ 3

Author(s):

Guangxi Wu ◽

Haiying Ji ◽

Xiaoyu Guo ◽

Yongyong Li ◽

Tianbin Ren ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Outer Membrane ◽

Membrane Vesicles ◽

Outer Membrane Vesicles ◽

Fatal Infection ◽

Carbapenem Resistant ◽

Bacterial Outer Membrane

Download Full-text

Outer Membrane Vesicles Derived from Klebsiella pneumoniae Influence the miRNA Expression Profile in Human Bronchial Epithelial BEAS-2B Cells

Microorganisms ◽

10.3390/microorganisms8121985 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1985

Author(s):

Federica Dell’Annunziata ◽

Concetta Paola Ilisso ◽

Carmela Dell’Aversana ◽

Giuseppe Greco ◽

Alessandra Coppola ◽

...

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Klebsiella Pneumoniae ◽

Outer Membrane ◽

Expression Profile ◽

Mirna Expression ◽

Membrane Vesicles ◽

Outer Membrane Vesicles ◽

Human Bronchial Epithelial Cells ◽

Bronchial Epithelial

Klebsiella pneumoniae is an opportunistic pathogen that causes nosocomial and community-acquired infections. The spread of resistant strains of K. pneumoniae represents a growing threat to human health, due to the exhaustion of effective treatments. K. pneumoniae releases outer membrane vesicles (OMVs). OMVs are a vehicle for the transport of virulence factors to host cells, causing cell injury. Previous studies have shown changes of gene expression in human bronchial epithelial cells after treatment with K. pneumoniae OMVs. These variations in gene expression could be regulated through microRNAs (miRNAs), which participate in several biological mechanisms. Thereafter, miRNA expression profiles in human bronchial epithelial cells were evaluated during infection with standard and clinical K. pneumoniae strains. Microarray analysis and RT-qPCR identified the dysregulation of miR-223, hsa-miR-21, hsa-miR-25 and hsa-let-7g miRNA sequences. Target gene prediction revealed the essential role of these miRNAs in the regulation of host immune responses involving NF-ĸB (miR-223), TLR4 (hsa-miR-21), cytokine (hsa-miR-25) and IL-6 (hsa-let-7g miRNA) signalling pathways. The current study provides the first large scale expression profile of miRNAs from lung cells and predicted gene targets, following exposure to K. pneumoniae OMVs. Our results suggest the importance of OMVs in the inflammatory response.

Download Full-text