Objective To evaluate whether Vibrio vulnificus secreted exotoxin-hemolysin (VVH) can activate platelet, an important blood immune cell, and to explore the possible molecular mechanism of platelet activation by VVH. Methods Transcriptomics and immunohistochemistry were used to analyze whether Vibrio vulnificus infection caused platelet activation in mice. Then, flow cytometry was used to identify whether VVH was the main stimulator of platelet activation. Naturally expressed VVH toxin was purified and prepared. The effects of extracellular and intracellular Ca²⁺ signal inhibitors on VVH activated platelets were evaluated by flow cytometry and Western blotting. The immune activation effect of VVH in the early stage of Vibrio vulnificus infection was analyzed in vivo. Results VVH was the main stimulator of platelet activation in Vibrio vulnificus culture supernatant. Natural VVH can induce the increase of P-selectin (CD62P) on platelet surface, the formation of platelet-neutrophil complex (PNC), and the release of platelet microvesicles. The activation mechanism may be related to the VVH pore-dependent Ca²⁺-calmodulin (CaM) -myosin light chain kinase (MLCK) signaling pathway, which led to the release of platelet alpha particles and cascade activation of platelets. In a mouse model of ALD infected by Vibrio vulnificus gavage, VVH was strongly associated with platelet activation. Conclusion This study shows that VVH is an important platelet activating molecule in the early stage of Vibrio vulnificus infection, and its induction of platelet activation may be related to the pathogenic process.
Animals ; Platelet Activation/drug effects* ; Hemolysin Proteins/pharmacology* ; Vibrio vulnificus/metabolism* ; Mice ; Blood Platelets/drug effects* ; Vibrio Infections/immunology* ; P-Selectin/metabolism* ; Bacterial Proteins ; Female

Vibrio vulnificus causes fatal infections in susceptible individuals. Group 1 capsular polysaccharide (CPS) operon is responsible for CPS expression, which plays an essential role in the pathogenesis of this pathogen. Cyclic AMP (cAMP) and cAMP receptor protein (crp) complex, which responds to glucose availability and functions as a global regulator, has been known to affect CPS production in this pathogen. This study was undertaken to experimentally verify whether cAMP-Crp directly or indirectly affects CPS production. A mutation in cyaA encoding adenylate cyclase, which is required for cAMP biosynthesis, inhibited V. vulnificus growth and changed opaque colonies to translucent colonies, and these changes were recovered by complementing cyaA or by adding exogenous cAMP. A mutation in crp encoding Crp also inhibited V. vulnificus growth and changed opaque colonies to translucent colonies, and these changes were recovered by complementing crp. Moreover, the crp or cyaA mutation decreased the susceptibility of V. vulnificus against NaOCl. The crp mutation reduced the transcription levels of group 1 CPS operon on a per cell basis. Glucose addition in the absence of Crp stimulated V. vulnificus growth, changed translucent colonies to opaque colonies, and increased the transcription levels of group 1 CPS operon. These results indicate that cAMP or Crp is indirectly involved in optimal CPS production by positively affecting metabolism or V. vulnificus growth rather than by directly controlling the expression of group 1 CPS operon.
Adenylyl Cyclases ; Complement System Proteins ; Cyclic AMP Receptor Protein ; Cyclic AMP* ; Glucose ; Metabolism ; Operon ; Vibrio vulnificus

BACKGROUNDVibrio vulnificus (Vv) is an estuarine bacterium that can cause primary septicemia as well as serious wound infections. However, little is known about the mechanisms by which Vv infects dendritic cells (DCs) and its effects on cytoskeleton. In this study, we aimed to investigate the invasion, internalization, and the organelles damage of the cultured dendritic cells (a DC 2.4 strain) during Vv infection.

METHODSThe study model was the cultured DCs infected by a Vv 1.758 strain. Electron microscopy was used to observe the localization of bacteria at the different time points of infection, cell morphology, and the process of organelles changes. The cytoskeleton structure including the microfilaments and the microtubules rearrangement was examined under a fluorescence microscope.

RESULTSThe Vv were pinocytosised into the DC cells through double-sides, and localized at 1 - 2 mm of the inner side membrane. It took 1.3, 1.9, and 3.4 hours to reach the infection ratio of 25%, 50%, and 75%, respectively. Using electron microscopy, the DCs had been observed to have developed chromatin aggregation within 4.0 hours, and significant cytoskeleton structure disruption was noted within 6.0 hours.

CONCLUSIONThe high lethality of Vv infection may be associated with the direct disruption of the DCs cytoskeleton structure.

Animals ; Apoptosis ; physiology ; Cells, Cultured ; Cytoskeleton ; metabolism ; ultrastructure ; DNA Fragmentation ; Dendritic Cells ; metabolism ; microbiology ; ultrastructure ; Mice ; Microscopy, Electron ; Microscopy, Electron, Transmission ; Vibrio Infections ; metabolism ; Vibrio vulnificus ; pathogenicity

OBJECTIVETo investigate the influence of genetic polymorphism in NF-E2-related factor-2 (nrf2) gene promoter locus at 336 in alcoholic liver disease (ALD) with Vibrio vulnificus (VV) sepsis.

METHODSThrough the simple random sampling method, C57B6 male mice were divided into normal feeding group (group A, 10 mice), alcoholic liver disease group (group B, 10 mice), normal feeding group infected with VV through intraperitoneal injection (group C, 8 mice), alcoholic liver disease group infected with VV (group D, 110 mice). Through gene sequencing method, nrf2 gene promoter 336 polymorphism in D group was analyzed and grouped into: non-mutation group (336T) (group D1, 7 mice) and mutation group (336C) (group D2, 10 mice). Through RT-PCR, Western-blotting and ELISA method, expressions of nrf2, tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), high mobility group protein 1 (HMGB(1)) gene and protein of liver were measured. The pathological changes in liver were recorded with light microscope.

RESULTSAfter infected with VV for 48 hours for A, B, C, D1, D2 group, the expression medians of nrf2 mRNA in liver were 0.115, 0.173, 0.211, 0.764, 0.352, respectively (χ(2) = 40.64, P < 0.05), the expression medians of IL-10 mRNA in liver were 0.338, 0.637, 1.002, 1.825, 1.403, respectively (χ(2) = 41.05, P < 0.05), the expression medians of TNF-α mRNA in liver were 0.140, 0.254, 0.372, 0.399, 0.699, respectively (χ(2) = 38.16, P < 0.05), the expression medians of HMGB(1) mRNA in liver were 0.230, 0.410, 0.668, 0.508, 1.021, respectively (χ(2) = 31.45, P < 0.05). After infected with VV 48 hours for mice in A, B, C, D1, D2 group, the expression medians of nrf2 protein in liver were 0.908, 1.461, 2.061, 3.982, 2.243, respectively (χ(2) = 33.72, P < 0.05), the expression medians of IL-10 protein in liver were 13.97, 22.54, 30.14, 57.98, 41.53, respectively (χ(2) = 37.31, P < 0.05), the expression medians of TNF-α protein in liver were 114.07, 142.94, 175.44, 174.60, 266.11, respectively (χ(2) = 32.29, P < 0.05), the expression medians of HMGB(1) protein in liver were 2.01, 6.05, 9.62, 6.24, 12.89, respectively (χ(2) = 36.94, P < 0.05). Compared with group A, there were large amount of fat drops, fatty changes in group B, inflammatory cell infiltration, disorder of hepatic cell in group C, and extension of hepatic duct and vein, edema of liver cells and disorder of hepatic cells in group D.

CONCLUSIONThe nrf2 gene promoter of T336C mutation in C57B6 mouse of ALD can significantly decrease the expression of nrf2, and intensify organ inflammation and damage when they were infected by VV.

Animals ; Liver Diseases, Alcoholic ; complications ; genetics ; metabolism ; microbiology ; Male ; Mice ; Mice, Inbred C57BL ; NF-E2-Related Factor 2 ; genetics ; metabolism ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic ; Sepsis ; complications ; genetics ; microbiology ; Vibrio Infections ; complications ; genetics ; Vibrio vulnificus

We identified 6 sucrose-fermenting Vibrio vulnificus strains and examined their virulence characteristics. They were all encapsulated, motile, capable of producing toxins and utilizing transferrin-bound iron, cytotoxic to cultured cells, and virulent enough to kill mice. They could be definitely identified only by genetic identification methods such as PCR, and not by conventional culture-based identification methods such as API 20E (bioMerieux, France). These results indicate that it is essential to adopt genetic approaches as early as possible in order to avoid misdiagnosis of such strains, especially in clinical situations.
Animals ; Bacterial Proteins/genetics ; Fermentation ; Mice ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Sucrose/*metabolism ; Vibrio vulnificus/genetics/growth & development/*pathogenicity ; Virulence

BACKGROUNDSepticemia and inflammation-mediated septic shock caused by Vibrio vulnificus (VV) is strongly associated with chronic liver disease. This study examined the effects of antimicrobial therapy on expression of hepatic toll-like receptors and inflammatory cytokines in rats with alcohol-induced liver disease complicated by VV sepsis.

METHODSMale Sprague-Dawley rats were assigned to the following treatment groups: normal control (N), alcoholic liver disease control (A), antimicrobial-treated alcoholic liver disease control (AA), alcoholic liver disease with VV sepsis (AV), and antimicrobial-treated alcoholic liver disease with VV sepsis (AVA). Alcohol-induced liver disease was observed in all groups except N. Expression of mRNAs encoding hepatic toll-like receptors 2 and 4, myeloid differentiation protein-2, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6 and IL-10 was determined by RT-PCR.

RESULTSmRNAs encoding toll-like receptors 2 and 4 and myeloid differentiation protein-2 were significantly up-regulated in group AV as compared to control groups at 2 - 24 hours of sepsis; peak expression occurred at 12 hours. These mRNAs were also up-regulated in group AVA but to lesser degrees than in group AV at comparable time post-infection. mRNAs encoding TNF-alpha, IL-1beta and IL-6 were significantly elevated in group AV as a function of infection. In group AVA as compared to AV, expression of TNF-alpha and IL-1beta mRNAs was lower at 12 - 24 hours post-infection and expression of IL-6 mRNA was lower at 24 hours post-infection. Compared with control groups, IL-10 mRNA expression in group AV was markedly higher at 12 - 24 hours of sepsis. Expression of IL-10 mRNA was lower in group AVA as compared to AV at 24 hours of sepsis.

CONCLUSIONSAntimicrobial therapy reduces expression of toll-like receptors and cytokines in rats with alcohol-induced liver disease complicated by VV sepsis. Monitoring hepatic toll-like receptor and cytokine expression during antibiotic therapy may be valuable for determining the course of VV sepsis in subjects with liver disease.

Adaptor Proteins, Signal Transducing ; genetics ; Animals ; Anti-Infective Agents ; therapeutic use ; Cytokines ; genetics ; Interleukin-10 ; genetics ; Interleukin-1beta ; genetics ; Interleukin-6 ; genetics ; Liver ; drug effects ; metabolism ; Liver Diseases, Alcoholic ; drug therapy ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Sepsis ; drug therapy ; genetics ; microbiology ; Toll-Like Receptor 2 ; genetics ; Toll-Like Receptor 4 ; genetics ; Toll-Like Receptors ; genetics ; Tumor Necrosis Factor-alpha ; genetics ; Vibrio Infections ; drug therapy ; Vibrio vulnificus ; physiology

OBJECTIVETo detect the effects of antimicrobial agents on the toll-like receptor (TLR) and so on in liver tissue of rats after intragastric infusion with alcohol with vibrio vulnificus (VV) sepsis.

METHODSSprague-Dawley rats were randomly divided into normal control group (N group, n = 6), rats after intragastric infusion with alcohol control group (group A, n = 6), drug intervention on rats after intragastric infusion with alcohol control group (group AA, n = 6), rats after intragastric infusion with alcohol with VV sepsis group (group AV, n = 24, killed at 2, 6, 12, 24 hours after injecting VV respectively, six rats per group), as well as drug intervention on rats after intragastric infusion with alcohol with vibrio vulnificus sepsis group (group AVA, n = 30, killed at 6, 12, 24 hours and one week after injecting VV respectively, six rats per group). The expressions and dynamic changes of TLR4 mRNA and so on by RT-PCR in liver tissue of each group were measured.

RESULTSThe expressions of TLR4 mRNA in AV-6 hours group was 0.775 +/- 0.101, the expressions of TLR4 mRNA in AVA-6 hours group was 0.600 +/- 0.064; the expressions of TLR4 mRNA in AV-12 hours group was 0.918 +/- 0.133, the expressions of TLR4 mRNA in AVA-12 hours group was 0.583 +/- 0.112; the expressions of TLR4 mRNA in AV-24 hours group was 0.732 +/- 0.110, the expressions of TLR4 mRNA in AVA-24 hours group was 0.512 +/- 0.118. Compared with AV group, the expressions of TLR4 mRNA in liver diminished greatly in AVA group at 6, 12 and 24 hours after being injected with VV (AVA-6 hours group compare with AV-6 hours group, t = -3.573, P < 0.01; AVA-12 hours group compared with AV-12 hours group, t = - 4.722, P < 0.01; AVA-24 hours group compare with AV-24 hours group, t = - 3.340, P < 0.01).

CONCLUSIONThe treatment with antibacterial agents may reduced the expression of TLR and so on in liver of rats after intragastric infusion with alcohol with VV sepsis. The treatment with antibacterial agents may regulate the balance of the inflammatory response in VV sepsis and generate the visible therapeutical effect for VV sepsis.

Animals ; Disease Models, Animal ; Ethanol ; Interleukin-10 ; metabolism ; Liver ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Sepsis ; immunology ; metabolism ; Toll-Like Receptors ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Vibrio vulnificus

Among the exotoxins produced by V. vulnificus, hemolysin (HS) has been reported to be the most potent one. To investigate the factors up- or down-regulating HS production in the context of pathogenesis, we observed the effects of salinity or/and temperature shifting, glucose, and acidic pH on the production of HS by V. vulnificus C7184 strain in vitro. Significantly more HS was produced when V. vulnificus was cultured in 0.9% salinity and 37 degrees C than in 2.5% and 25 degrees C. When the culture condition reflecting natural habitat of V. vulnificus (2.5% salinity and 25degrees C) was changed into that reflecting human body (0.9% salinity and 37 degrees C), 2.5 fold or more HS was produced than in the V. vulnificus being cultured continuously in 0.9% NaCl at 37 degrees C. This result suggests that V. vulnificus somehow recognizes the shifting in salinity and temperature and stimulate HS production. Glucose addition in the culture medium resulted in a dose- dependent decrease in the HS production. Glucose itself and acidic pH resulting from its metabolism both appeared to inhibit the HS production. Glucose in itself had more dominant role in suppressing the HS production than the lowered pH accompanying the metabolism of glucose. This result suggests that HS production is down-regulated in the presence of glucose and under environmental acidic pH.
Ecosystem ; Exotoxins ; Glucose* ; Human Body ; Hydrogen-Ion Concentration ; Metabolism ; Salinity* ; Vibrio vulnificus* ; Vibrio* ; Virulence

Vibrio vulnificus cytolysin forms transmembrane pores that are permeable to calcium ions in pulmonary endothelial cells, and has been suggested as an important virulence factor that sequestrate neutrophils primarily in the lung. To elucidate the mechanism we investigated whether the cytolysin affect the expression of endothelial P-selectin and adhesiveness of pulmonary endothelial cells for neutrophils. The cytolysin increased the adhesiveness of CPAE cell, a pulmonary endothelial cell line, for neutrophils in a concentrationand time-dependent manner. The increase of adhesiveness occurred within several minutes after the cytolysin exposure, persisted up to 90 min, and was not affected by cycloheximide. Furthermore, flow cytometric analyses showed that cytolysin enhanced the level of P-selectin on CPAE cell surface. Therefore, these results suggest that the cytolysin-induced hyperadhesiveness of pulmonary endothelial cells for neutrophils is mediated by the mobilization of endothelial P-selectin to the cell surface.
Animals ; Cattle ; Cell Adhesion/*drug effects ; Cell Line ; Cycloheximide/pharmacology ; Cytotoxins/*toxicity ; Dose-Response Relationship, Drug ; Endothelium, Vascular/cytology/*drug effects/metabolism ; Kinetics ; Neutrophils/*drug effects/pathology ; P-Selectin/*metabolism ; Protein Synthesis Inhibitors/pharmacology ; Pulmonary Artery/cytology/*drug effects/metabolism ; Rats ; Vibrio Infections/etiology/pathology ; Vibrio vulnificus/*pathogenicity

Vibrio vulnificus cytolysin forms transmembrane pores that are permeable to calcium ions in pulmonary endothelial cells, and has been suggested as an important virulence factor that sequestrate neutrophils primarily in the lung. To elucidate the mechanism we investigated whether the cytolysin affect the expression of endothelial P-selectin and adhesiveness of pulmonary endothelial cells for neutrophils. The cytolysin increased the adhesiveness of CPAE cell, a pulmonary endothelial cell line, for neutrophils in a concentrationand time-dependent manner. The increase of adhesiveness occurred within several minutes after the cytolysin exposure, persisted up to 90 min, and was not affected by cycloheximide. Furthermore, flow cytometric analyses showed that cytolysin enhanced the level of P-selectin on CPAE cell surface. Therefore, these results suggest that the cytolysin-induced hyperadhesiveness of pulmonary endothelial cells for neutrophils is mediated by the mobilization of endothelial P-selectin to the cell surface.
Animals ; Cattle ; Cell Adhesion/*drug effects ; Cell Line ; Cycloheximide/pharmacology ; Cytotoxins/*toxicity ; Dose-Response Relationship, Drug ; Endothelium, Vascular/cytology/*drug effects/metabolism ; Kinetics ; Neutrophils/*drug effects/pathology ; P-Selectin/*metabolism ; Protein Synthesis Inhibitors/pharmacology ; Pulmonary Artery/cytology/*drug effects/metabolism ; Rats ; Vibrio Infections/etiology/pathology ; Vibrio vulnificus/*pathogenicity