Characteristics and complete genome sequence of the virulent Vibrio alginolyticus phage VAP7, isolated in Hainan, China.

A novel Vibrio alginolyticus phage, VAP7, was isolated from seawater collected from Sanya, Hainan province, China. Whole-genome sequencing analysis revealed that phage VAP7 has a linear, double-stranded DNA genome of 144,685 bp with an average G+C content of 41.9% and a high degree of sequence similarity to Vibrio phage VP-1. Annotation results identified 193 open reading frames and one transfer RNA-encoding gene in the phage genome. The morphology and the results of phylogenetic analysis suggest that VAP7 should be classified as a new member of the family Ackermannviridae. Moreover, phage VAP7 grew over a wide pH (5.0-10.0) and temperature (4-40 °C) range. Host-range experiments revealed that VAP7 could infect 31 Vibrio alginolyticus strains. Thus, VAP7 infecting Vibrio alginolyticus strains represents a potential new candidate for use in phage therapy.

Isolation and Characterization of a Novel Bacteriophage Infecting Carbapenem-Resistant Klebsiella pneumoniae.

A novel virulent phage, vB_KpnP_IME337, isolated from a hospital sewage in Beijing, China, that infects carbapenem-resistant Klebsiella pneumoniae KN2 capsular type was identified and characterized. Next-generation sequencing and genome analysis revealed that vB_KpnP_IME337 had a linear double-stranded genome with a length of 44,266 base pairs and G+C content of 53.7%. Fifty-two putative open reading frames were identified, and no transfer RNA-encoding genes were detected. BLASTn analysis revealed that phage vB_KpnP_IME337 had the highest sequence similarity with Klebsiella phage phiBO1E, with genome coverage of 79%. Based on morphology, phage vB_KpnP_IME337 was determined to belong to the family Podoviridae of the order Caudovirales. It was shown that phage vB_KpnP_IME337 had an infection duration of ~ 90 min and 10 min latent period, and a highly specific to host strain. In conclusion, phage vB_KpnP_IME337 may be a promising alternative candidate to antibiotic treatment for controlling diseases caused by drug-resistant K. pneumoniae.

Safety, pharmacokinetics, and pharmacodynamics of anti-IL-4Rα antibody SHR-1819 in healthy subjects: A randomized, controlled phase I study.

SHR-1819 is a novel anti-IL-4Rα monoclonal antibody currently under clinical development for use in patients with type 2 inflammatory diseases. In this randomized, double-blind, placebo-controlled, single-dose escalation phase I trial, we evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of SHR-1819 in healthy subjects. Subjects received a single subcutaneous injection of SHR-1819 or placebo, with dose escalation starting at 60 mg and subsequently increasing to 120, 240, 360, and 720 mg. A total of 42 eligible subjects were randomized, and 33 received SHR-1819 (1 subject in the 60 mg cohort and 8 subjects each in the 120, 240, 360 , and 720 mg cohorts) and 9 received placebo. SHR-1819 was well-tolerated, with the majority of adverse events being mild in severity. The exposure of SHR-1819 increased in a manner greater than proportionally with a dose range of 120 to 720 mg. The median Tmax was within 4-7 days (60-720 mg), and the mean half-life ranged from 2.88 to 5.97 days (120-720 mg). The clearance rate of SHR-1819 exhibited a decrease with increasing dose level. Administration of SHR-1819 resulted in a certain degree of reduction in the percentage change from baseline in concentrations of inflammatory biomarkers TARC/CCL17 and IgE, while the reduction of TARC/CCL17 concentrations showed a dose-dependent trend. More than half of the total subjects treated with SHR-1819 were reported antidrug antibody-negative. The preliminary data from this phase I study support further development of SHR-1819 for the treatment of type 2 inflammatory diseases.

A recombinant pseudotyped lentivirus expressing the envelope glycoprotein of hantaan virus induced protective immunity in mice.

BACKGROUND: Hantaviruses cause acute hemorrhagic fever with renal syndrome (HFRS). Currently, several types of inactivated HFRS vaccines are widely used, however the limited ability of these immunogen to elicit neutralizing antibodies restricts vaccine efficacy. Development of an effective vaccine to overcome this weakness is must. METHODS: In the present study, a recombinant pseudotyped lentivirus bearing the hantaan virus (HTNV) envelope glycoproteins (GP), rLV-M, was constructed. C57BL/6 mice were immunized with the rLV-M and a series of immunological assays were conducted to determine the immunogenicity of the recombinant pseudotyped lentivirus. The humoral and cell-mediated immune responses induced by rLV-M were compared with those of the inactivated HFRS vaccine. RESULTS: Indirect immunofluorescence assay (IFA) showed the rLV-M expressed target proteins in HEK-293 cells. In mice, the rLV-M efficiently induced GP-specific humoral responses and protection against HTNV infection. Furthermore, the rLV-M induced higher neutralizing antibody titers than the inactivated HFRS vaccine control. CONCLUSIONS: The results indicated the potential of using a pseudotyped lentivirus as a delivery vector for a hantavirus vaccine immunogen.

Tigecycline in the treatment of fulminant Mycoplasma pneumoniae pneumonia non-responsive to azithromycin and fluoroquinolone: A case report.

RATIONALE: Fulminant macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) has seldom been reported, and cases of MPP usually show rapid improvement after fluoroquinolones or tetracyclines addition. The purpose of this case report is to highlight the importance of proper selection of antibiotics for treatment of severe MPP and increase awareness concerning the emergence of fluoroquinolone-resistant MPP. PATIENT CONCERNS: A case of severe life-threatening pneumonia in a 26-year-old man with high fever and cough was non-responsive to azithromycin and fluoroquinolones. DIAGNOSES: The patient was diagnosed with MPP based on the test results of bronchoalveolar lavage using real-time quantitative PCR method. INTERVENTIONS: Tigecycline was given to the patient after azithromycin and fluoroquinolones failed. OUTCOMES: The patients fever subsided within the first day of tigecycline therapy. He showed rapid symptom resolution and improvement in lung infiltration after 4 days of tigecycline therapy. LESSONS: The case suggests that fulminant MPP should be timely treated with proper antibiotics, and the possible emergence of fluoroquinolone-resistant MPP should be of concern.

Development and Evaluation of a Loop-Mediated Isothermal Amplification Assay for Rapid and Specific Identification of Carbapenem-Resistant Acinetobacter baumannii Strains Harboring blaOXA-23, and the Epidemiological Survey of Clinical Isolates.

Acinetobacter baumannii is an important nosocomial pathogen in hospital-acquired infections, and carbapenem resistance has been increasingly observed worldwide. Oxacillinase production by blaOXA-23 is a predominant and prevalent carbapenem resistance mechanism of A. baumannii, especially in China. Rapid and specific detection of blaOXA-23 may offer valuable insight for administration of directed antimicrobial therapy. In this study, we aimed to develop a loop-mediated isothermal amplification (LAMP)-based method for identifying carbapenem-resistant A. baumannii (CRAB) harboring the blaOXA-23 gene. High-specificity primers for screening blaOXA-23 were designed and synthesized, and the LAMP reactions were performed. Clinical A. baumannii strains isolated from the Former 307th Hospital of People's Liberation Army were used to determine the sensitivity and specificity of this method compared with those of phenotypic antimicrobial susceptibility testing and the traditional PCR method. Multilocus sequence typing (MLST) was performed to investigate the epidemiology of the A. baumannii bacterial population. Compared with antimicrobial susceptibility testing, the sensitivity and specificity of LAMP in detecting blaOXA-23 were 88.4% and 97.7%, respectively. However, the LAMP method is much simpler and less time-consuming (within 60 minutes) than conventional PCR and phenotypic susceptibility testing. The 113 isolates could be clustered into 30 sequence types, and most strains (83/113) belonged to clonal complex (CC) 92, which is also the dominant CC in China. The LAMP-based method detected blaOXA-23 in a simpler manner and could provide rapid results for identifying CRAB. Consequently, blaOXA-23 may serve as a surrogate marker for the presence of CRAB in patients with serious infections in clinical practice.

Identification of a Novel Acinetobacter baumannii Phage-Derived Depolymerase and Its Therapeutic Application in Mice.

The rapid expansion of Acinetobacter baumannii clinical isolates exhibiting resistance to most or all available antibiotics is a global concern. Current treatments for infections caused by this bacterium have become less effective, and the need to explore new alternative therapies is urgent. Depolymerases derived from phages are emerging as attractive anti-virulence agents. In this study, a previously isolated A. baumannii phage (designated as vB_AbaM_IME285) was characterized, and genomic study was carried out using various bioinformatics tools. A gene predicted as encoding for the depolymerase was cloned and expressed, and the depolymerase activity of the recombinant enzyme (Dp49) was identified both in vitro and in experimental mice. The results showed that phage IME285 formed translucent halos around the plaques when inoculated onto a lawn of the host bacteria, exibiting depolymerase activity against this strain. On the basis of complete genome sequencing and bioinformatics analysis, ORF49 was speculated to be a gene encoding for the putative capsule depolymerase. The expressed recombinant Dp49 displayed an effective depolymerase activity and had a spectrum of activity similar to its parental phage IME285, which was active against 25 out of 49 A. baumannii strains. It was found that Dp49 greatly improved the inhibitory effect of serum on bacterial growth in vitro, and the administration of this enzyme significantly increased the survival rates of A. baumannii-infected mice in the animal experiment. In conclusion, the phage-encoded depolymerase Dp49 might be a promising alternative means of controlling infections mediated by multidrug-resistant A. baumannii.

Identification of Two Depolymerases From Phage IME205 and Their Antivirulent Functions on K47 Capsule of Klebsiella pneumoniae.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) pose a significant threat to global public health. In present research, a total of 80 CRKP strains belonging to ST11 were collected with 70% (56 of 80 isolates) expressing a K47 capsular type. Thus, it is significant to prevent and control infections caused by these bacteria. Capsule depolymerases could degrade bacterial surface polysaccharides to reduce their virulence and expose bacteria to host immune attack. Previous studies have demonstrated the potential of phage-encoded depolymerases as antivirulent agents in treating CRKP infections in vitro and in vivo. Here, two capsule depolymerases (Dpo42 and Dpo43) derived from phage IME205 were expressed and characterized. Although both depolymerases act on strains with a capsular serotype K47, they are active against different subsets of strains, indicating subtle differences in capsule composition that exist within this serotype. The host range of phage IME205 matched to the sum of specificity range of Dpo42 and Dpo43. These two enzymes maintained stable activity in a relatively broad range of pH levels (pH 5.0-8.0 for Dpo42 and pH 4.0-8.0 for Dpo43) and temperatures (20-70°C). Besides, both Dpo42 and Dpo43 could make host bacteria fully susceptible to the killing effect of serum complement and display no hemolytic activity to erythrocytes. In summary, capsule depolymerases are promising antivirulent agents to combat CRKP infections.

Efficacy of pulmonary transplantation of engineered macrophages secreting IL-4 on acute lung injury in C57BL/6J mice.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are major causes of respiratory failure, but currently, no effective pharmacotherapy exists for these disorders. Alveolar macrophages play a critical role in both the acute/initial phase and chronic/resolving phase of ALI, rendering them a potential therapeutic target. Interleukin-4 (IL-4), a Th2 cytokine, not only directly inhibits the secretion of pro-inflammatory factors from macrophages but also drives macrophages to the anti-inflammatory and tissue remodeling M2 type. However, the short half-life of IL-4 in vivo hampers its effect on disease treatment. In this study, macrophages secreting IL-4 (M-IL-4) were established and used to treat ALI through pulmonary macrophage transplantation (PMT). The results showed that highly sustained levels of IL-4 and M2 macrophage markers were detected in mice lungs following pulmonary M-IL-4 transplantation. Furthermore, PMT improved the therapeutic effect by reducing lung inflammation, alleviating tissue injury, reducing alveolar macrophages necrotic cell death, and decreasing mortality in mice with ALI. These results suggest an efficient macrophage-based protein drug delivery strategy, and for the first time, prove the feasibility and efficacy of PMT in ALI treatment.

The Capsule Depolymerase Dpo48 Rescues Galleria mellonella and Mice From Acinetobacter baumannii Systemic Infections.

The emergence of multidrug- and extensively drug-resistant Acinetobacter baumannii has made it difficult to treat and control infections caused by this bacterium. Thus, alternatives to conventional antibiotics for management of severe A. baumannii infections is urgently needed. In our previous study, we found that a capsule depolymerase Dpo48 could strip bacterial capsules, and the non-capsuled A. baumannii were significantly decreased in the presence of serum complement in vitro. Here, we further explored its potential as a therapeutic agent for controlling systemic infections caused by extensively drug-resistant A. baumannii. Prior to mammalian studies, the anti-virulence efficacy of Dpo48 was first tested in a Galleria mellonella infection model. Survival rate of Dpo48-pretreated bacteria or Dpo48 treatment group was significantly increased compared to the infective G. mellonella without treatment. Furthermore, the safety and therapeutic efficacy of Dpo48 to mice were evaluated. The mice treated with Dpo48 displayed normal serum levels of TBIL, AST, ALT, ALP, Cr, BUN and LDH, while no significant histopathology changes were observed in tissues of liver, spleen, lung, and kidney. Treatment with Dpo48 could rescue normal and immunocompromised mice from lethal peritoneal sepsis, with the bacterial counts in blood, liver, spleen, lung, and kidney significantly reduced by 1.4-3.3 log colony-forming units at 4 h posttreatment. Besides, the hemolysis and cytotoxicity assays showed that Dpo48 was non-homolytic to human red blood cells and non-toxic to human lung, liver and kidney cell lines. Overall, the present study demonstrated the promising potential of capsule depolymerases as therapeutic agents to prevent antibiotic-resistant A. baumannii infections.

[Corrigendum] NLRP3 inflammasome is responsible for Hantavirus inducing interleukin­1ß in THP­1 cells.

Subsequently to the publication of the above article, the authors have realized that an error was introduced in the preparation of Fig. 2B for publication. In Fig. 2B, the lanes shown for the western blot were misannotated. Additionally, in the legend of Fig. 2C, '24 h post­infection' should have been written as '12 h post­infection'. Furthermore, the description of the data shown in Fig. 2B in the Results section (sentence commencing on p. 1635, the subsection 'HTNV activates caspase­1 and pro­IL­1ß in THP­1 cells', line 10), was incomplete. The sentence here should have read as follows (the added text is highlighted in bold): 'In order to investigate whether caspase­1 was activated during HTNV infection, the culture supernatant of HTNV­infected THP­1 was ultra­ï¬ltered and an increased concentration of secreted caspase­1 was detected post­infection compared with the Mock group; similar results were also observed in the LPS­ and ATP­stimulated groups (Fig. 2B)'. The correct version of Fig. 2, with the lanes of the western blot in Fig. 2B labelled correctly and the appropriate changes having been made to the Figure legend, is shown opposite. The errors associated with this Figure did not have an impact on the overall meaning of the paper, or on the reported conclusions of this study. The authors regret that this Figure was not corrected prior to the publication of this article, and apologize to the readership for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 35: 1633­1640, 2015; DOI: 10.3892/ijmm.2015.2162].

Corrigendum: The Capsule Depolymerase Dpo48 Rescues Galleria mellonella and Mice From Acinetobacter baumannii Systemic Infections.

[This corrects the article DOI: 10.3389/fmicb.2019.00545.].

Protective and therapeutic application of the depolymerase derived from a novel KN1 genotype of Klebsiella pneumoniae bacteriophage in mice.

Klebsiella pneumoniae is one of the major Gram-negative bacterial pathogens causing hospital-acquired multidrug-resistant infections, and the antimicrobial treatment options are scarce. The lack of available antimicrobials has prompted the development of alternative strategies for the treatment of these infections. In this study, a K. pneumoniae bacteriophage (vB_KpnP_IME321) targeting a KN1 capsular type strain, Kp409, was isolated, characterized and sequenced. This bacteriophage has a latent period of 20 min and a burst size of approximately 410 pfu/cell. It contained 49 predicted open reading frames, of which ORF42 was identified as encoding the putative capsule depolymerase. The enzyme expressed and purified in the Escherichia coli BL21 system, namely Dp42, could depolymerize the capsular polysaccharide of Kp409 and form translucent halos on the plates. The phage-encoded depolymerase could increase the inhibitory effect of serum on the growth of bacteria in vitro. Pre-treated with Dp42 rescued 100% of mice following lethal Kp409 challenge, and administration of this enzyme after infection significantly increased survival rates of infected mice in the animal experiment. In conclusion, the phage-encoded depolymerase Dp42 represents a potential alternative strategy for controlling infections mediated by K. pneumoniae expressing the KN1 capsular polysaccharide.

Identification and characterization of capsule depolymerase Dpo48 from Acinetobacter baumannii phage IME200.

BACKGROUND: The emergence of multidrug- or extensively drug-resistant Acinetobacter baumannii has made it difficult to treat and control infections caused by this bacterium. It is urgently necessary to search for alternatives to conventional antibiotics for control of severe A. baumannii infections. In recent years, bacteriophages and their derivatives, such as depolymerases, showed great potential as antibacterial or antivirulence agents against bacterial infections. Nonetheless, unlike broad-spectrum bactericidal antibiotics, phage-encoded depolymerase targets only a limited number of bacterial strains. Therefore, identification of novel depolymerases and evaluation of their ability to control A. baumannii infections is important. METHODS: A bacteriophage was isolated from hospital sewage using an extensively drug-resistant A. baumannii strain as the host bacterium, and the phage's plaque morphology and genomic composition were studied. A polysaccharide depolymerase (Dpo48) was expressed and identified, and the effects of pH and temperature on its activity were determined. Besides, a serum killing assay was conducted, and amino acid sequences homologous to those of putative polysaccharide depolymerases were compared. RESULTS: Phage IME200 yielded clear plaques surrounded by enlarged halos, with polysaccharide depolymerase activity against the host bacterium. A tail fiber protein with a Pectate_lyase_3 domain was identified as Dpo48 and characterized . Dpo48 was found to degrade the capsule polysaccharide of the bacterial surface, as revealed by Alcian blue staining. Dpo48 manifested stable activity over a broad range of pH (5.0-9.0) and temperatures (20-70 °C). Results from in vitro serum killing assays indicated that 50% serum was sufficient to cause a five log reduction of overnight enzyme-treated bacteria, with serum complement playing an important role in these killing assays. Moreover, Dpo48 had a spectrum of activity exactly the same as its parental phage IME200, which was active against 10 out of 41 A. baumannii strains. Amino acid sequence alignment showed that the putative tail fiber proteins had a relatively short, highly conserved domain in their N-terminal sequences, but their amino acid sequences containing pectate lyase domains, found in the C-terminal regions, were highly diverse. CONCLUSIONS: Phage-encoded capsule depolymerases may become promising antivirulence agents for preventing and controlling A. baumannii infections.

Rapid detection of Mycoplasma pneumoniae by loop-mediated isothermal amplification assay.

To improve the diagnosis and treatment of Mycoplasma pneumoniae (Mp) infection and reduce the misuse of antibiotics, we sought to establish a loop-mediated isothermal amplification (LAMP) assay for rapid detection of Mp.Six primers specific for the Mp P1 gene were designed, and the LAMP method was used to rapidly detect Mp. The sensitivity of the LAMP method was determined by serial dilution of the standard Mp strain FH (standard strains of Mycoplasma pneumoniae). Specificity was assessed with 17 common pathogenic microorganisms in the respiratory tract. Patient samples were collected from the Department of Respiratory and Critical Care Medicine at the 307th Hospital of Chinese People's Liberation Army from March 2016 to May 2017, examined prospectively, and compared with diagnosis by quantitative real-time polymerase chain reaction (qRT-PCR).The LAMP assay for Mp detection can be completed within 60 minutes. The minimum detection limit was 39 pg/µL, and no cross-reaction was observed with 17 common respiratory tract pathogens. Of the 125 clinical specimens tested, 43 cases were positive by LAMP assay, and 40 cases were positive by qRT-PCR (P = .162). All 43 samples determined as positive by LAMP test were confirmed to be Mp by Mp P1 protein sequencing.The LAMP assay is suitable for rapid detection of Mp. It has high sensitivity and specificity, and the detection results are not inferior to those of qRT-PCR.

Rapid visual detection of binary toxin producing Clostridium difficile by loop-mediated isothermal amplification.

The binary toxin Clostridium difficile transferase (CDT) is frequently observed in C. difficile strains and is associated with an increased severity of C. difficile infection. CDT-producing C. difficile infections cause higher fatality rates than infections with CDT negative isolates. Thus, the rapid and accurate identification of a CDT positive C. difficile infection is critical for effective treatment. The present study demonstrates how loop-mediated isothermal amplification (LAMP) can be used to detect CDT-producing C. difficile based on visual observation. This is a low complexity, rapid molecular method that has the potential to be used within a point of care setting. The specificity and sensitivity of the primers in the LAMP reactions for CDT detection were determined using two different methods, a real-time turbidity monitor and visual detection after the addition of calcein to the reaction tube. The results revealed that target DNA was amplified and visualized by these two detection methods within 60 min at a temperature of 60°C. The sensitivity of the LAMP assay was identified to be 10-fold greater than that of polymerase chain reaction analysis. When 25 alternative bacterial strains lacking CDT were tested, the results of the amplification were negative, confirming the specificity of the primers. In conclusion, the visual LAMP method established in the present study may be a rapid, reliable and cost-effective tool for detecting CDT-producing C. difficile strains at the point of care.

Combination therapy of human umbilical cord mesenchymal stem cells and FTY720 attenuates acute lung injury induced by lipopolysaccharide in a murine model.

ALI/ARDS remain the main reason of morbidity and mortality in the critically ill. Studies have indicated that human umbilical cord mesenchymal stem cells (hUC-MSCs) can be useful in the treatment of ALI/ARDS. Sphingosine-1-phosphate (S1P) and its analog FTY720 significantly reduce lipopolysaccharide (LPS)-induced lung edema and inflammatory lung injury. This study aimed to assess the therapeutic effects of hUC-MSCs combined with FTY720 in an LPS-induced murine model of ALI. Eight-week-old female C57BL/6 mice were divided into a normal control group, an LPS group, an hUC-MSC group, an FTY720 group, and an hUC-MSCs+FTY720 group randomly. At 24 hours post injury, mice were administrated hUC-MSCs via the tail vein and/or intraperitoneally injected with FTY720. We assessed histopathology and histologic scores, lung wet/dry weight ratio, micro-CT scans, and total protein in the bronchoalveolar lavage fluid (BALF), as well as cytokines in the BALF at 48 h post injury. All treatment groups showed higher survival rates and attenuated lung injuries. The hUC-MSCs+FTY720 group yielded better results than hUC-MSCs or FTY720 alone. While the underlying mechanism requires further study, we anticipate that combination therapy of hUC-MSCs and FTY720 could be an effective strategy for ALI.

Isolation and Whole-genome Sequence Analysis of the Imipenem Heteroresistant Acinetobacter baumannii Clinical Isolate HRAB-85.

OBJECTIVES: Heteroresistance is a phenomenon in which there are various responses to antibiotics from bacterial cells within the same population. Here, we isolated and characterised an imipenem heteroresistant Acinetobacter baumannii strain (HRAB-85). METHODS: The genome of strain HRAB-85 was completely sequenced and analysed to understand its antibiotic resistance mechanisms. Population analysis and multilocus sequence typing were performed. RESULTS: Subpopulations grew in the presence of imipenem at concentrations of up to 64µg/mL, and the strain was found to belong to ST208. The total length of strain HRAB-85 was 4,098,585bp with a GC content of 39.98%. The genome harboured at least four insertion sequences: the common ISAba1, ISAba22, ISAba24, and newly reported ISAba26. Additionally, 19 antibiotic-resistance genes against eight classes of antimicrobial agents were found, and 11 genomic islands (GIs) were identified. Among them, GI3, GI10, and GI11 contained many ISs and antibiotic-resistance determinants. CONCLUSIONS: The existence of imipenem heteroresistant phenotypes in A. baumannii was substantiated in this hospital, and imipenem pressure, which could induce imipenem-heteroresistant subpopulations, may select for highly resistant strains. The complete genome sequencing and bioinformatics analysis of HRAB-85 could improve our understanding of the epidemiology and resistance mechanisms of carbapenem-heteroresistant A. baumannii.

Regulation of S1P receptors and sphingosine kinases expression in acute pulmonary endothelial cell injury.

BACKGROUND: Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) is a severe clinical syndrome with mortality rate as high as 30-40%. There is no treatment yet to improve pulmonary endothelial barrier function in patients with severe pulmonary edema. Developing therapies to protect endothelial barrier integrity and stabilizing gas exchange is getting more and more attention. Sphingosine-1-phosphate (S1P) is able to enhance the resistance of endothelial cell barrier. S1P at physiological concentrations plays an important role in maintaining endothelial barrier function. Proliferation, regeneration and anti-inflammatory activity that mesenchymal stem cells (MSCs) exhibit make it possible to regulate the homeostatic control of S1P. METHODS: By building a pulmonary endothelial cell model of acute injury, we investigated the regulation of S1P receptors and sphingosine kinases expression by MSCs during the treatment of acute lung injury using RT-PCR, and investigated the HPAECs Micro-electronics impedance using Real Time Cellular Analysis. RESULTS: It was found that the down-regulation of TNF-α expression was more significant when MSC was used in combination with S1P. The combination effection mainly worked on S1PR2, S1PR3 and SphK2. The results show that when MSCs were used in combination with S1P, the selectivity of S1P receptors was increased and the homeostatic control of S1P concentration was improved through regulation of expression of S1P metabolic enzymes. DISCUSSIONS: The study found that, as a potential treatment, MSCs could work on multiple S1P related genes simultaneously. When it was used in combination with S1P, the expression regulation result of related genes was not simply the superposition of each other, but more significant outcome was obtained. This study establishes the experimental basis for further exploring the efficacy of improving endothelial barrier function in acute lung injury, using MSCs in combination with S1P and their possible synergistic mechanism.

Complete Genome Sequence of IME207, a Novel Bacteriophage Which Can Lyse Multidrug-Resistant Klebsiella pneumoniae and Salmonella.

A novel lytic Salmonella bacteriophage was isolated by using Klebsiella pneumoniae as host cells. The phage's genome was determined to be 47,564 bp and has the highest similarity to Salmonella phage E1 and Salmonella phage 64795_sal3, with coverages of 61% and 56%, respectively. Here, we announce the phage's complete genome.