USP8 inhibition regulates autophagy flux and controls Salmonella infection

Introduction

Ubiquitination is an important protein modification that regulates various essential cellular processes, including the functions of innate immune cells. Deubiquitinases are enzymes responsible for removing ubiquitin modification from substrates, and the regulation of deubiquitinases in macrophages during infection with Salmonella Typhimurium and Yersinia enterocolitica remains unknown.

Methods

To identify deubiquitinases regulated in human macrophages during bacterial infection, an activity-based proteomics screen was conducted. The effects of pharmacological inhibition of the identified deubiquitinase, USP8, were examined, including its impact on bacterial survival within macrophages and its role in autophagy regulation during Salmonella infection.

Results

Several deubiquiitnases were differentially regulated in infected macrophages. One of the deubiquitinases identified was USP8, which was downregulated upon Salmonella infection. Inhibition of USP8 was associated with a decrease in bacterial survival within macrophages, and it was found to play a distinct role in regulating autophagy during Salmonella infection. The inhibition of USP8 led to the downregulation of the p62 autophagy adaptor.

Discussion

The findings of this study suggest a novel role of USP8 in regulating autophagy flux, which restricts intracellular bacteria, particularly during Salmonella infection.

Extracellular vesicles elicit protective immune responses against Salmonella infection

Small extracellular vesicles (sEVs) produced by antigen-presenting cells represent a novel mechanism of cell-to-cell communication. The sEVs have been shown to drive Th1-type adaptive immune responses against intracellular infections such as Salmonella. In this study, we have demonstrated that an administration of sEVs produced by Salmonella-infected macrophages to BALB/c mice that were then challenged with Salmonella infection decreased bacterial load in infected animals and led to protection against a lethal dose of Salmonella. Second, the same sEVs induced a robust production of IgA anti-Salmonella antibodies (Abs) in BALB/c mice, including IgA anti-OmpD Abs. These results show that the nanoscale sEVs stimulate adaptive immune responses against intracellular pathogens and that these sEVs can be used to provide animals with complete protection against lethal infection, such as the systemic bacterial infection in immunodeficient BALB/c mice.

Fluorescent Labeling of Small Extracellular Vesicles (EVs) Isolated from Conditioned Media

Extracellular vesicles (EVs), such as exosomes, are produced by all known eukaryotic cells, and constitute essential means of intercellular communication. Recent studies have unraveled the important roles of EVs in migrating to specific sites and cells. Functional studies of EVs using in vivo and in vitro systems require tracking these organelles using fluorescent dyes or, alternatively, transfected and fluorescent-tagged proteins, located either intravesicularly or anchored to the EV bilayer membrane. Due to design simplicity, the fluorescent dye might be a preferred method if the cells are difficult to modify by transfection or when the genetic alteration of the mother cells is not desired. This protocol describes techniques to label cultured cell-derived EVs, using lipophilic DiR [DiIC18(7) (1,1'-Dioctadecyl-3,3,3',3'-Tetramethylindotricarbocyanine Iodide)] fluorophore. This technique can be used to study the cellular uptake and intracellular localization of EVs, and their biodistribution in vivo , which are crucial evaluations of any isolated EVs.

Antigen-encapsulating host extracellular vesicles derived from Salmonella-infected cells stimulate pathogen-specific Th1-type responses in vivo

Salmonella Typhimurium is a causative agent of nontyphoidal salmonellosis, for which there is a lack of a clinically approved vaccine in humans. As an intracellular pathogen, Salmonella impacts many cellular pathways. However, the intercellular communication mechanism facilitated by host-derived small extracellular vesicles (EVs), such as exosomes, is an overlooked aspect of the host responses to this infection. We used a comprehensive proteome-based network analysis of exosomes derived from Salmonella-infected macrophages to identify host molecules that are trafficked via these EVs. This analysis predicted that the host-derived small EVs generated during macrophage infection stimulate macrophages and promote activation of T helper 1 (Th1) cells. We identified that exosomes generated during infection contain Salmonella proteins, including unique antigens previously shown to stimulate protective immune responses against Salmonella in murine studies. Furthermore, we showed that host EVs formed upon infection stimulate a mucosal immune response against Salmonella infection when delivered intranasally to BALB/c mice, a route of antigen administration known to initiate mucosal immunity. Specifically, the administration of these vesicles to animals stimulated the production of anti-Salmonella IgG antibodies, such as anti-OmpA antibodies. Exosomes also stimulated antigen-specific cell-mediated immunity. In particular, splenic mononuclear cells isolated from mice administered with exosomes derived from Salmonella-infected antigen-presenting cells increased CD4+ T cells secreting Th1-type cytokines in response to Salmonella antigens. These results demonstrate that small EVs, formed during infection, contribute to Th1 cell bias in the anti-Salmonella responses. Collectively, this study helps to unravel the role of host-derived small EVs as vehicles transmitting antigens to induce Th1-type immunity against Gram-negative bacteria. Understanding the EV-mediated defense mechanisms will allow the development of future approaches to combat bacterial infections.

[The association between single nucleotide polymorphism of interleukin-1β gene rs1143627 site and susceptibility to active tuberculosis]

Objective: To investigate the relationship between single nucleotide polymorphism (SNP) of IL-1β gene and susceptibility to tuberculosis. Methods: A case-control study was conducted in Shenzhen Third People's Hospital from January 2012 to December 2014. A total of 1 533 patients with active tuberculosis were enrolled, including 1 432 cases of pulmonary tuberculosis[920 males and 512 females, mean age (37±14) years] and 101 cases of extrapulmonary tuberculosis [60 males and 41 females, mean age (35±13) years]. At the same time, 1 445 healthy controls (882 males and 563 females, mean age (37±20) years) were selected. The genotypes of rs1143627, rs1143623, rs16944 and rs2853550 of IL-1β gene were detected by time-of-flight mass spectrometry. The allele frequencies of rs1143627 T>C (-31) were compared between patients with pulmonary tuberculosis and those with extrapulmonary tuberculosis. Fifty-three patients with active tuberculosis [male 32, female 21, mean age (37±15) years] were randomly selected, and the correlation between SNP alleles and tuberculosis severity was analyzed before and after treatment. Results: Time-of-flight mass spectrometry effectively detected the genotypes of 4 SNP loci. Among the 4 SNP loci, only the allele frequency of -31 locus was significantly different between the active tuberculosis group and the control group. The allele frequency of rs1143627 T locus in active tuberculosis group was 53.3%(1 634/3 066), which was significantly higher than that in the healthy control group 48.7%(1 407/2 890; OR=1.20, 95%CI=1.09-1.33, P=0.001 6) .The frequencies of the other 3 SNP alleles were not significantly different between the active tuberculosis group and the control group. The frequencies of the other 3 SNP alleles were 59% (1 821/3 066) and 60% (1 732/2 890) for rs1143623 G allele, 51% (1 574/3 066) and 52% (1 499/2 890) for rs16944 G allele, and 64% (1 964/3 066) and 65% (1 875/2 890) for rs2853550 T allele respectively. Stratified analysis showed that the frequency of the -31 T allele in patients with extrapulmonary tuberculosis (62.9%, 127/202) was significantly higher than that in patients with pulmonary tuberculosis (52.6%,1 507/2 864) (OR=1.53; 95% CI=1.13-2.05; P=0.005).The HRCT scores of patients with rs1143627 TT, TC and CC genotypes were 26.6, 13.9 and 13.3 respectively before anti-tuberculosis treatment, and after 2 years of anti-tuberculosis treatment, the HRCT scores of patients with rs1143627 TT, TC and CC genotypes were 14.7, 6.6 and 5.4 respectively, which indicated that TB patients with rs1143627T allele were associated with more severe pulmonary disease. Conclusion: The SNP of IL-1β-31T>C was associated with susceptibility to active tuberculosis, and T allele was the susceptible gene and individuals carrying T allele were more likely to develop extrapulmonary tuberculosis.

Influence of salmonid aquaculture activities on a rock-cliff epifaunal community in Jervis Inlet, British Columbia

Benthic video surveys were carried out at two marine finfish aquaculture and associated reference sites in Jervis Inlet (JI), British Columbia. Substrate composition, epifaunal diversity, mat-forming taxa (primary indicators: opportunistic polychaete complexes (OPCs) and sulfide-oxidizing bacteria) and waste pellets were quantitatively assessed. Hard-bottom substrates were dominated by rock wall, skeletal sponge matrix, graded bedrock, rock-veneer, and cobble. Aquaculture waste outputs (modelled depositional carbon fluxes and observations of waste feed/faecal pellets) were correlated with benthic organic enrichment indicators (OPC and sulfide-oxidizing bacteria). Sulfide-oxidizing bacteria varied in abundance up to a modelled depositional carbon flux of ~2gCm^-2day^-1 where it sustained 50% areal coverage. Glass sponges revealed an inverse relationship with aquaculture waste outputs and sulfide-oxidizing bacteria. Plumose anemones and shrimp showed a low frequency of occurrence at reference sites; however, they were abundant within the near-field zone of the aquaculture sites associated with a higher modelled carbon flux. Future research should focus on the response of various taxa to depositional gradients and their potential role as secondary indicators of aquaculture activities associated with rock-cliff communities.

The prevalence of latent tuberculosis infection in rural Jiangsu, China

OBJECTIVES

Diagnosis and interventional treatment of latent tuberculosis (TB) infection (LTBI) are important components in tuberculosis control. But systematic studies regarding the epidemic of LTBI are still rare in China. The objective of this study was to assess the prevalence and risk factors associated with LTBI based on the results of a domestic TB-specific gamma interferon (IFN-γ) release assay (TB-IGRA) in rural Jiangsu, China.

STUDY DESIGN

Cross-sectional study of subjects registered in eight villages in Jiangsu, China.

METHODS

This study was conducted in 2012 in eight villages. After recruitment, individuals with active TB or a history of TB were excluded. The TB-IGRA was performed for diagnosis of LTBI.

RESULTS

2169 of 2185 subjects met the requirement and were analysed in this study. 524 (24.3%) had a positive result, and positive rate gradually increased with age (P for trend <0.001). Multivariate analyses showed that increasing age, male gender and a history of TB exposure were risk factors associated with LTBI. Bacillus Calmette-Guérin (BCG) vaccination did not reduce the risk of TB infection in participants (aged ≥20 years).

CONCLUSIONS

The findings of this study demonstrate that the prevalence of LTBI in China might be overestimated by tuberculin skin test compared with IFN-γ release assay (IGRA). The degree of TB exposure is related to Mycobacterium tubercuium (MTB) infection, and BCG vaccination offers little protection against MTB infection in adults. The early and effective detection and treatment of active TB patients, and screening and intervention for LTBI patients with a high risk of developing active TB could be cost-effective methods for TB control in China.

Inhibition of cdk9 during herpes simplex virus 1 infection impedes viral transcription

During herpes simplex virus 1 (HSV-1) infection there is a loss of the serine-2 phosphorylated form of RNA polymerase II (RNAP II) found in elongation complexes. This occurs in part because RNAP II undergoes ubiquitination and proteasomal degradation during times of highly active viral transcription, which may result from stalled elongating complexes. In addition, a viral protein, ICP22, was reported to trigger a loss of serine-2 RNAP II. These findings have led to some speculation that the serine-2 phosphorylated form of RNAP II may not be required for HSV-1 transcription, although this form is required for cellular transcription elongation and RNA processing. Cellular kinase cdk9 phosphorylates serine-2 in the C-terminal domain (CTD) of RNAP II. To determine if serine-2 phosphorylated RNAP II is required for HSV-1 transcription, we inhibited cdk9 during HSV-1 infection and measured viral gene expression. Inhibition was achieved by adding cdk9 inhibitors 5,6-dichlorobenzimidazone-1-β-D-ribofuranoside (DRB) or flavopiridol (FVP) or by expression of a dominant–negative cdk9 or HEXIM1, which in conjunction with 7SK snRNA inhibits cdk9 in complex with cyclin 1. Here we report that inhibition of cdk9 resulted in decreased viral yields and levels of late proteins, poor formation of viral transcription-replication compartments, reduced levels of poly(A)+ mRNA and decreased RNA synthesis as measured by uptake of 5-bromouridine into nascent RNA. Importantly, a global reduction in viral mRNAs was seen as determined by microarray analysis. We conclude that serine-2 phosphorylation of the CTD of RNAP II is required for HSV-1 transcription.

Complete Genome Sequence of a thermotolerant sporogenic lactic acid bacterium, Bacillus coagulans strain 36D1

Bacillus coagulans is a ubiquitous soil bacterium that grows at 50-55 °C and pH 5.0 and ferments various sugars that constitute plant biomass to L (+)-lactic acid. The ability of this sporogenic lactic acid bacterium to grow at 50-55 °C and pH 5.0 makes this organism an attractive microbial biocatalyst for production of optically pure lactic acid at industrial scale not only from glucose derived from cellulose but also from xylose, a major constituent of hemicellulose. This bacterium is also considered as a potential probiotic. Complete genome sequence of a representative strain, B. coagulans strain 36D1, is presented and discussed.

Human telomerase RNA gene (TERC) gain and polysomy of chromosome 3 in cervicovaginal liquid-based pap preparations: a fluorescence in situ hybridization study

PURPOSE. This study investigated human telomerase RNA gene (TERC) gain and polysomy of chromosome 3 in cervicovaginal liquid-based pap preparations in Guilin, China, and assessed the relationship between FISH findings and clinical diagnoses. METHODS. Slides prepared from 63 liquid-based preparations with cytologic diagnoses of negative for squamous intraepithelial lesion or malignancy (NILM n = 9), atypical squamous cells of undetermined significance (ASCUS, n = 18), low-grade squamous intraepithelial lesion (LSIL, n = 14), high-grade squamous intraepithelial lesion (HSIL, n = 9), and cervical squamous cell carcinoma (SCCA, n = 13) were analyzed for TERC gain and polysomy of chromosome 3 using a commercially available two-color FISH probe. The results of the cytologic analysis and those of concurrent or subsequent biopsies, when available, were compared with the FISH findings. The Mann-Whitney test was used to assess associations between FISH findings and diagnoses. RESULTS. TERC gain and polysomy of chromosome 3 were significantly associated with the cytologic diagnosis (p? 0.001). Patients with HSIL or SCCA cytology diagnoses had a significantly higher percentage of cells with TERC gain and polysomy of chromosome 3 than did patients with NILM, ASCUS or LSIL cytologic diagnoses. Those abnormal cases with CIN1 histological diagnosis had a significantly lower percentage of cells with TERC gain and polysomy of chromosome 3 than did patients with a CIN2, CIN3 and SCCA histological diagnosis. CONCLUSIONS. TERC gain and polysomy of chromosome 3 may be important associated genetic events in cervical intraepithelial neoplasia and carcinoma. FISH is a potential tool for the diagnoses of uterine cervix disease.

Fermentation of sugar cane bagasse hemicellulose hydrolysate to L(+)-lactic acid by a thermotolerant acidophilic Bacillus sp

Sugar cane bagasse hemicellulose, hydrolyzed by dilute H2SO4, supplemented with mineral salts and 0.5% corn steep liquor, was fermented to L(+)-lactic acid using a newly isolated strain of Bacillus sp. In batch fermentations at 50 degrees C and pH 5, over 5.5% (w/v) L(+)-lactic acid was produced (89% theoretical yield; 0.9 g lactate per g sugar) with an optical purity of 99.5%.

[The detection of virus antigen in the lower respiratory tract of the patients with lung cancer]

OBJECTIVE

To find out about the viral infection situation of lower respiratory tract of the patients with lung cancer.

METHODS

The excretion from the surface of bronchiogenic carcinoma was brushed under fibrobronchoscopy. The respiratory virus antigen was detected and analysed by reagent kit produced by the 262nd Hospital of Beijing Military Region.

RESULTS

The respiratory virus antigen was positive in eight cases of lung cancer group, the positive rate was 17.4%(8/46), it was significantly higher than that in non-lung cancer group (P < 0.05). Among them, there were one case of influenza virus A, two cases of influenza virus B, two cases of para-influenza 1,3, two cases of adenovirus and one case of respiratory syncytial virus. The carcinoma accompanied with viral infection were 4,3,1, cases in order of squamous carcinoma, small cell lung carcinoma and adenocarcinoma.

CONCLUSION

The results showed that a relationship existed between lung cancer and viral infection of respiratory tract statistically. The viral infection increased in patients with lung cancer, this is worthy to pay attention to.

p53 overexpression and downregulation of inter-alpha-inhibitor are associated with hyaluronidase enhancement of TNF cytotoxicity in L929 fibroblasts

Degradation of extracellular matrix by hyaluronidase increases murine L929 cell sensitivity to tumor necrosis factor (TNF) cytotoxicity. Seeding and culturing L929 cells onto the matrix of serum fetuin and the hyaluronate-binding inter-alpha-inhibitor resulted in inhibition of hyaluronidase-enhanced TNF killing, suggesting that the release of these proteins from hyaluronidase-degraded matrix confers cellular TNF susceptibility. Metabolic labeling studies showed that hyaluronidase mediated de novo protein synthesis and down regulated several proteins in L929 cells. Specifically, hyaluronidase upregulated p53 protein expression (>200%) but down regulated a p85 inter-alpha-inhibitor-like protein (>90%) in L929 cells, whereas it had no effect on the protein levels of ICH-1, Bcl-xL, Bcl-2, Fas ligand, CAS (cellular apoptosis susceptible protein), TIAR (an RNA-binding protein) and alpha-tubulin. Conceivably, hyaluronidase enhancement of TNF sensitivity in L929 cells is p53-dependent and the matrix inter-alpha-inhibitor contributes a protective role against TNF cytotoxicity.

[Factors influencing morale among the elderly in long-term care]

The purpose of this research was to investigate the factors which influence morale among the elderly in long-term care. The sampling criteria for subjects were that they were (1) 65 years old or older and were residents or care recipients at a nursing home, day care or home care center which participated in the experimental project in Department of Health; (2) able to understand the Mandarin or Taiwanese language; (3) capable of verbal communication; and (4) family caregivers whose elder family met the above three requirements. A total sample of 174 subjects consisting of 87 elderly and 87 caregivers were chosen. Research findings revealed: the mean score for morale for elderly in this study was 11.71 out of range 2-19. Except for birthplace and caring models, there was no significant difference among the elderly. The elderly born in Taiwan had significantly higher morale than those born in Mainland China. The elderly in day care had significantly higher morale than those in home care and nursing homes. No significant difference was found among family caregivers, except for family caregivers who had changed their job due to the demands of caring for elderly relations. Elderly in this situation showed significantly lower morale in the elderly whose family caregivers did not change jobs. Correlation analysis showed a positive relationship between the elderly's level of daily activity and their morale level. Higher morale in the elderly was also found to be positively related to perceived higher levels of social support in family caregivers. In multiple regression, morale among the elderly was used as the criterion variable, while the variables of birth place, functional status, caregivers' perceived social support, home care, nursing home, changed job, never having had a job, caregivers' sex caregivers' educational level were used as predictors. The explanation variance achieved using the above research model was 30.78%. Recommendations derived from this study include suggesting the establishment of community adult day care centers to facilitate the elderly being able to stay within their communities, and to provide mental support for caregivers.

Analysis on decay rate of vibration following impact to human dry skull with and without mouthguards

The modal analysis on vibration in the human dry skull with and without mouthguards was performed in order to clarify which elasticity modulus of the material and what form of the mouthguard are best. Nine different mouthguards were prepared for this study from three materials with different elasticity moduli amd three different forms: Soft MOLTENO (registered) mouthguards of long, middle, and short forms. Regular MOLENTO (registered) mouthguards of long, middle and short forms, and Hard MOLENTO(registered) mouthguards of long, middle and short forms. Thirty-five measurement points were established on the skull. The main measurement system was composed of a 512-D Vibration Generator, LV-1300 Laser-Doppler Vibrometer, CF-6400 FFT Analyzer, PC-9821Xn personal computer, and Vibrant PC modal analysis software. The decay rate was calculated to evaluate effectiveness of the absorption of vibration of the skull with and without mouthguards when stress was put on the skull. The results showed that he skull fitted with the long and middle mouthguards made of regular MOLTENO (registered) had a higher decay rate than the skull w the mouthguard, and that the material properties of the mouthguards influenced the absorption of the skull vibration more intensively that did the forms of the mouthguards.

A new method of purification and sensitive bioassay of platelet-activating factor (PAF) in human whole blood

There is no satisfactory assay procedure of PAF in human whole blood in terms of sensitivity, reproducibility and simplicity. This is due to coexisting lipids from plasma and cellular membranes which inhibit measurement of PAF in various assay procedures, including bioassay. In the present study, an attempt was made to eliminate these interfering lipid inhibitors from blood samples. Lipids in human whole blood were extracted according to the method of Bligh & Dyer and the organic layer was dried under a stream of nitrogen. Then, the dried organic layer was dissolved in diethyl-ether and the solution was kept at -20 degrees C which was then centrifuged. The resulting supernatant was then applied to an anion-exchange column and the PAF fraction was obtained by step-wise gradient elution. The fraction was further purified by normal phase HPLC. Then PAF in the final sample was determined by sensitive bioassay using rabbit platelets containing fibrinogen and epinephrine. The recovery rate of PAF throughout this procedure was constant and satisfactory (37.4 +/- 9.7%), which was confirmed using [3H]-PAF. The lower limit of the present assay was estimated to be 5pg in 1 ml of blood and it was sensitive enough to detect PAF in blood samples from healthy volunteers and patients with sepsis or liver cirrhosis. Furthermore, attempts were made to compare the sensitivity and the recovery of our method with these of a commercially available radioimmunoassay (RIA) kit for PAF. However, it was not possible to detect any amount of authentic PAF added to whole blood.

[Effect of yin and qi tonifying herbs on hyperthyroid model of yin-deficient rats]

The article reports the effect of Yin and Qi tonifying herbs (Radix Rehmanniae, Radix Ophiopogonis and Pseudostellaria Heterophylla) on hyperthyroid model of Yin-deficient rats. The model rats were made Yin-deficient by injecting thyroxine. Observation showed that after injection, indexes such as anus temperature, oxygen consumption, weight, diet, activity, general conditions, triiodothyronine (T3) and thyroxine (T4) in serum were markedly changed. It is thus suggested that the Yin and Qi tonifying mixture of the above three herbs can regulate and correct Yin-deficiency in hyperthyroid model of Yin-deficient rats.

Species differences in platelet aggregation induced by platelet-activating factor (PAF)

Species differences in platelet aggregation induced by platelet-activating factor (PAF) were investigated by using the same procedure of platelet preparation and biological assay. Washed platelets of six different species (horses, dogs, rats, rabbits, sheep and guinea pigs) were prepared employing the same method and platelet aggregation was induced by C16-PAF. Horse platelets were most sensitive to PAF (8.0 x 10(-12) M) and rabbit platelets activated by 5.0 x 10(-11) M PAF were also sensitive enough to detect PAF in clinical samples.

Simple and rapid measurement of platelet-activating factor (PAF) in whole blood

A simple assay of platelet-activating factor (PAF) in whole blood was developed, employing acetone extraction and thin layer chromatography (TLC) purification of blood sample. The activity of acetylhydrolase present in blood sample was almost completely suppressed by ice-cold acetone extraction, and other inhibitory substances interfering the activity of PAF were effectively removed from the acetone extract by TLC. Then, the treated samples were subjected to a conventional PAF bioassay using rabbit platelets. The recovery rate of PAF by the above procedure was constant and feasible (46-48%). The lower limit of the present assay was estimated to be 1.0 x 10(-10) M. Employing the present method, it was able to determine the amount of PAF in blood (1.2-6.0 x 10(-10) M) of 6 out of 14 septic patients, while no significant PAF activity was detected in the samples from 6 healthy subjects. These results indicate a potential application of the present method in the clinical assay of PAF in blood.