Blood microbial signatures associated with mortality in patients with sepsis: A pilot study.

Sepsis is a life-threatening illness caused by the dysregulated host response to infection. Nevertheless, our current knowledge of the microbial landscape in the blood of septic patients is still limited. Next-generation sequencing (NGS) is a sensitive method to quantitatively characterize microbiomes at various sites of the human body. In this study, we analyzed the blood microbial DNA of 22 adult patients with sepsis and 3 healthy subjects. The presence of non-human DNA was identified in both healthy and septic subjects. Septic patients had a markedly altered microbial DNA profile compared to healthy subjects over α- and ß-diversity. Unexpectedly, the patients could be further divided into two subgroups (C1 and C2) based on ß-diversity analysis. C1 patients showed much higher bacteria, viruses, fungi, and archaea abundance, and a higher level of α-diversity (Chao1, Observed and Shannon index) than both C2 patients and healthy subjects. The most striking difference was seen in the case of Streptomyces violaceusniger, Phenylobacterium sp. HYN0004, Caulobacter flavus, Streptomyces sp. 11-1-2, and Phenylobacterium zucineum, the abundance of which was the highest in the C1 group. Notably, C1 patients had a significantly poorer outcome than C2 patients. Moreover, by analyzing the patterns of microbe-microbe interactions in healthy and septic subjects, we revealed that C1 and C2 patients exhibited distinct co-occurrence and co-exclusion relationships. Together, our study uncovered two distinct microbial signatures in the blood of septic patients. Compositional and ecological analysis of blood microbial DNA may thus be useful in predicting mortality of septic patients.

LOX-1 acts as an N6-methyladenosine-regulated receptor for Helicobacter pylori by binding to the bacterial catalase.

The role of N6-methyladenosine (m6A) modification of host mRNA during bacterial infection is unclear. Here, we show that Helicobacter pylori infection upregulates host m6A methylases and increases m6A levels in gastric epithelial cells. Reducing m6A methylase activity via hemizygotic deletion of methylase-encoding gene Mettl3 in mice, or via small interfering RNAs targeting m6A methylases, enhances H. pylori colonization. We identify LOX-1 mRNA as a key m6A-regulated target during H. pylori infection. m6A modification destabilizes LOX-1 mRNA and reduces LOX-1 protein levels. LOX-1 acts as a membrane receptor for H. pylori catalase and contributes to bacterial adhesion. Pharmacological inhibition of LOX-1, or genetic ablation of Lox-1, reduces H. pylori colonization. Moreover, deletion of the bacterial catalase gene decreases adhesion of H. pylori to human gastric sections. Our results indicate that m6A modification of host LOX-1 mRNA contributes to protection against H. pylori infection by downregulating LOX-1 and thus reducing H. pylori adhesion.

3'untranslated regions of tumor suppressor genes evolved specific features to favor cancer resistance.

Cancer-related genes have evolved specific genetic and genomic features to favor tumor suppression. Previously we reported that tumor suppressor genes (TSGs) acquired high promoter CpG dinucleotide frequencies during evolution to maintain high expression in normal tissues and resist cancer-specific downregulation. In this study, we investigated whether 3'untranslated regions (3'UTRs) of TSGs have evolved specific features to carry out similar functions. We found that 3'UTRs of TSGs, especially those involved in multiple histological types and pediatric cancers, are longer than those of non-cancer genes. 3'UTRs of TSGs also exhibit higher density of binding sites for RNA-binding proteins (RBPs), particularly those having high affinities to C-rich motifs. Both longer 3'UTR length and RBP binding sites enrichment are correlated with higher gene expression in normal tissues across tissue types. Moreover, both features together with the correlated N6-methyladenosine modification and the extent of protein-protein interactions are positively associated with the ability of TSGs to resist cancer-specific downregulation. These results were successfully validated with independent datasets. Collectively, these findings indicate that TSGs have evolved longer 3'UTR with increased propensity to RBP binding, N6-methyladenosine modification and protein-protein interactions for optimizing their tumor-suppressing functions.

Single-Hit Inactivation Drove Tumor Suppressor Genes Out of the X Chromosome during Evolution.

Cancer-related genes are under intense evolutionary pressure. In this study, we conjecture that X-linked tumor suppressor genes (TSG) are not protected by the Knudson's two-hit mechanism and are therefore subject to negative selection. Accordingly, nearly all mammalian species exhibited lower TSG-to-noncancer gene ratios on their X chromosomes compared with nonmammalian species. Synteny analysis revealed that mammalian X-linked TSGs were depleted shortly after the emergence of the XY sex-determination system. A phylogeny-based model unveiled a higher X chromosome-to-autosome relocation flux for human TSGs. This was verified in other mammals by assessing the concordance/discordance of chromosomal locations of mammalian TSGs and their orthologs in Xenopus tropicalis. In humans, X-linked TSGs are younger or larger in size. Consistently, pan-cancer analysis revealed more frequent nonsynonymous somatic mutations of X-linked TSGs. These findings suggest that relocation of TSGs out of the X chromosome could confer a survival advantage by facilitating evasion of single-hit inactivation. SIGNIFICANCE: This work unveils extensive trafficking of TSGs from the X chromosome to autosomes during evolution, thus identifying X-linked TSGs as a genetic Achilles' heel in tumor suppression.

Stress Hyperglycemia Is Associated With an Increased Risk of Subsequent Development of Diabetes Among Bacteremic and Nonbacteremic Patients.

OBJECTIVE: Stress hyperglycemia is associated with an increased risk of diabetes among survivors of critical illness. We investigated whether patients without diabetes hospitalized for bacteremia or nonbacteremic diseases with transient stress hyperglycemia would have a higher risk of subsequent diabetes development compared with those who remained normoglycemic. RESEARCH DESIGN AND METHODS: This retrospective observational study was conducted on 224,534 in-patients with blood culture records. Stress hyperglycemia was defined based on the highest random glucose level ≥7.8 mmol/L during the index admission period. Diagnosis of diabetes, as the primary end point of interest, was defined based on diagnostic codes, blood test results, or medication records. Differences in cumulative incidence and hazard ratios (HRs) of diabetes between groups were assessed using the Kaplan-Meier estimator and Cox regression. RESULTS: After exclusion of patients with preexisting or undiagnosed diabetes or indeterminate diabetes status and propensity score matching, bacteremic patients with stress hyperglycemia had a significantly higher cumulative incidence of diabetes (HR 1.7, 95% CI 1.2-2.4) compared with those who remained normoglycemic. Stress hyperglycemia was further confirmed to be a diabetes predictor independent of age, sex, comorbidity, and other serological markers. For the nonbacteremic patients, stress hyperglycemia was similarly associated with a higher cumulative incidence of diabetes (HR 1.4, 95% CI 1.2-1.7). CONCLUSIONS: Hospitalized patients with transient stress hyperglycemia had a higher risk of subsequent diabetes development compared with their normoglycemic counterparts. Recognition of an increased risk of diabetes in these patients can allow early detection and monitoring in their subsequent follow-ups.

Vitamin D3 and carbamazepine protect against Clostridioides difficile infection in mice by restoring macrophage lysosome acidification.

Clostridioides difficile infection (CDI) is a common cause of nosocomial diarrhea. TcdB is a major C. difficile exotoxin that activates macrophages to promote inflammation and epithelial damage. Lysosome impairment is a known trigger for inflammation. Herein, we hypothesize that TcdB could impair macrophage lysosomal function to mediate inflammation during CDI. Effects of TcdB on lysosomal function and the downstream pro-inflammatory SQSTM1/p62-NFKB (nuclear factor kappa B) signaling were assessed in cultured macrophages and in a murine CDI model. Protective effects of two lysosome activators (i.e., vitamin D3 and carbamazepine) were assessed. Results showed that TcdB inhibited CTNNB1/ß-catenin activity to downregulate MITF (melanocyte inducing transcription factor) and its direct target genes encoding components of lysosomal membrane vacuolar-type ATPase, thereby suppressing lysosome acidification in macrophages. The resulting lysosomal dysfunction then impaired autophagic flux and activated SQSTM1-NFKB signaling to drive the expression of IL1B/IL-1ß (interleukin 1 beta), IL8 and CXCL2 (chemokine (C-X-C motif) ligand 2). Restoring MITF function by enforced MITF expression or restoring lysosome acidification with 1α,25-dihydroxyvitamin D3 or carbamazepine suppressed pro-inflammatory cytokine expression in vitro. In mice, gavage with TcdB-hyperproducing C. difficile or injection of TcdB into ligated colon segments caused prominent MITF downregulation in macrophages. Vitamin D3 and carbamazepine lessened TcdB-induced lysosomal dysfunction, inflammation and histological damage. In conclusion, TcdB inhibits the CTNNB1-MITF axis to suppress lysosome acidification and activates the downstream SQSTM1-NFKB signaling in macrophages during CDI. Vitamin D3 and carbamazepine protect against CDI by restoring MITF expression and lysosomal function in mice.Abbreviations: ATP6V0B: ATPase H+ transporting V0 subunit b; ATP6V0C: ATPase H+ transporting V0 subunit c; ATP6V0E1: ATPase H+ transporting V0 subunit e1; ATP6V1H: ATPase H+ transporting V1 subunit H; CBZ: carbamazepine; CDI: C. difficile infection; CXCL: chemokine C-X-X motif ligand; IL: interleukin; LAMP1: lysosomal-associated membrane protein 1; LC3: microtubule-associated protein 1 light chain 3; LEF: lymphoid enhancer binding factor 1; MITF: melanocyte inducing transcription factor; NFKB: nuclear factor kappa B; PMA: phorbol 12-myristate 13-acetate; TcdA: Clostridial toxin A; TcdB: Clostridial toxin B; TFE3: transcription factor E3; TFEB: transcription factor EB.

SARS-CoV-2 non-structural protein 6 triggers NLRP3-dependent pyroptosis by targeting ATP6AP1.

A recent mutation analysis suggested that Non-Structural Protein 6 (NSP6) of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a key determinant of the viral pathogenicity. Here, by transcriptome analysis, we demonstrated that the inflammasome-related NOD-like receptor signaling was activated in SARS-CoV-2-infected lung epithelial cells and Coronavirus Disease 2019 (COVID-19) patients' lung tissues. The induction of inflammasomes/pyroptosis in patients with severe COVID-19 was confirmed by serological markers. Overexpression of NSP6 triggered NLRP3/ASC-dependent caspase-1 activation, interleukin-1ß/18 maturation, and pyroptosis of lung epithelial cells. Upstream, NSP6 impaired lysosome acidification to inhibit autophagic flux, whose restoration by 1α,25-dihydroxyvitamin D3, metformin or polydatin abrogated NSP6-induced pyroptosis. NSP6 directly interacted with ATP6AP1, a vacuolar ATPase proton pump component, and inhibited its cleavage-mediated activation. L37F NSP6 variant, which was associated with asymptomatic COVID-19, exhibited reduced binding to ATP6AP1 and weakened ability to impair lysosome acidification to induce pyroptosis. Consistently, infection of cultured lung epithelial cells with live SARS-CoV-2 resulted in autophagic flux stagnation, inflammasome activation, and pyroptosis. Overall, this work supports that NSP6 of SARS-CoV-2 could induce inflammatory cell death in lung epithelial cells, through which pharmacological rectification of autophagic flux might be therapeutically exploited.

Outcomes of respiratory viral-bacterial co-infection in adult hospitalized patients.

BACKGROUND: Viral infections of the respiratory tract represent a major global health concern. Co-infection with bacteria may contribute to severe disease and increased mortality in patients. Nevertheless, viral-bacterial co-infection patterns and their clinical outcomes have not been well characterized to date. This study aimed to evaluate the clinical features and outcomes of patients with viral-bacterial respiratory tract co-infections. METHODS: We included 19,361 patients with respiratory infection due to respiratory viruses [influenza A and B, respiratory syncytial virus (RSV), parainfluenza] and/or bacteria in four tertiary hospitals in Hong Kong from 2013 to 2017 using a large territory-wide healthcare database. All microbiological tests were conducted within 48 h of hospital admission. Four etiological groups were included: (1) viral infection alone; (2) bacterial infection alone; (3) laboratory-confirmed viral-bacterial co-infection and (4) clinically suspected viral-bacterial co-infection who were tested positive for respiratory virus and negative for bacteria but had received at least four days of antibiotics. Clinical features and outcomes were recorded for laboratory-confirmed viral-bacterial co-infection patients compared to other three groups as control. The primary outcome was 30-day mortality. Secondary outcomes were intensive care unit (ICU) admission and length of hospital stay. Propensity score matching estimated by binary logistic regression was used to adjust for the potential bias that may affect the association between outcomes and covariates. FINDINGS: Among 15,906 patients with respiratory viral infection, there were 8451 (53.1%) clinically suspected and 1,087 (6.8%) laboratory-confirmed viral-bacterial co-infection. Among all the bacterial species, Haemophilus influenzae (226/1,087, 20.8%), Pseudomonas aeruginosa (180/1087, 16.6%) and Streptococcus pneumoniae (123/1087, 11.3%) were the three most common bacterial pathogens in the laboratory-confirmed co-infection group. Respiratory viruses co-infected with non-pneumococcal streptococci or methicillin-resistant Staphylococcus aureus was associated with the highest death rate [9/30 (30%) and 13/48 (27.1%), respectively] in this cohort. Compared with other infection groups, patients with laboratory-confirmed co-infection had higher ICU admission rate (p < 0.001) and mortality rate at 30 days (p = 0.028), and these results persisted after adjustment for potential confounders using propensity score matching. Furthermore, patients with laboratory-confirmed co-infection had significantly higher mortality compared to patients with bacterial infection alone. INTERPRETATION: In our cohort, bacterial co-infection is common in hospitalized patients with viral respiratory tract infection and is associated with higher ICU admission rate and mortality. Therefore, active surveillance for bacterial co-infection and early antibiotic treatment may be required to improve outcomes in patients with respiratory viral infection.

Annexin A2 traps mu-opioid receptors in recycling endosomes upon remifentanil-induced internalization.

•ANXA2 is a novel MOR1-interacting protein regulating MOR1 sub-cellular localization.•ANXA2 retains MOR1 in late recycling endosomes after remifentanil exposure.

Multi-omic analysis suggests tumor suppressor genes evolved specific promoter features to optimize cancer resistance.

Tumor suppressor genes (TSGs) exhibit distinct evolutionary features. We speculated that TSG promoters could have evolved specific features that facilitate their tumor-suppressing functions. We found that the promoter CpG dinucleotide frequencies of TSGs are significantly higher than that of non-cancer genes across vertebrate genomes, and positively correlated with gene expression across tissue types. The promoter CpG dinucleotide frequencies of all genes gradually increase with gene age, for which young TSGs have been subject to a stronger evolutionary pressure. Transcription-related features, namely chromatin accessibility, methylation and ZNF263-, SP1-, E2F4- and SP2-binding elements, are associated with gene expression. Moreover, higher promoter CpG dinucleotide frequencies and chromatin accessibility are positively associated with the ability of TSGs to resist downregulation during tumorigenesis. These results were successfully validated with independent datasets. In conclusion, TSGs evolved specific promoter features that optimized cancer resistance through achieving high expression in normal tissues and resistance to downregulation during tumorigenesis.

Lysosome activation in peripheral blood mononuclear cells and prognostic significance of circulating LC3B in COVID-19.

Coronavirus disease 2019 (COVID-19) has spread rapidly worldwide, causing significant mortality. There is a mechanistic relationship between intracellular coronavirus replication and deregulated autophagosome-lysosome system. We performed transcriptome analysis of peripheral blood mononuclear cells (PBMCs) from COVID-19 patients and identified the aberrant upregulation of genes in the lysosome pathway. We further determined the capability of two circulating markers, namely microtubule-associated proteins 1A/1B light chain 3B (LC3B) and (p62/SQSTM1) p62, both of which depend on lysosome for degradation, in predicting the emergence of moderate-to-severe disease in COVID-19 patients requiring hospitalization for supplemental oxygen therapy. Logistic regression analyses showed that LC3B was associated with moderate-to-severe COVID-19, independent of age, sex and clinical risk score. A decrease in LC3B concentration <5.5 ng/ml increased the risk of oxygen and ventilatory requirement (adjusted odds ratio: 4.6; 95% CI: 1.1-22.0; P = 0.04). Serum concentrations of p62 in the moderate-to-severe group were significantly lower in patients aged 50 or below. In conclusion, lysosome function is deregulated in PBMCs isolated from COVID-19 patients, and the related biomarker LC3B may serve as a novel tool for stratifying patients with moderate-to-severe COVID-19 from those with asymptomatic or mild disease. COVID-19 patients with a decrease in LC3B concentration <5.5 ng/ml will require early hospital admission for supplemental oxygen therapy and other respiratory support.

Streptococcus thermophilus Inhibits Colorectal Tumorigenesis Through Secreting ß-Galactosidase.

BACKGROUND & AIMS: Streptococcus thermophilus was identified to be depleted in patients with colorectal cancer (CRC) by shotgun metagenomic sequencing of 526 multicohort fecal samples. Here, we aim to investigate whether this bacterium could act as a prophylactic for CRC prevention. METHODS: The antitumor effects of S thermophilus were assessed in cultured colonic epithelial cells and in 2 murine models of intestinal tumorigenesis. The tumor-suppressive protein produced by S thermophilus was identified by mass spectrometry and followed by ß-galactosidase activity assay. The mutant strain of S thermophilus was constructed by homologous recombination. The effect of S thermophilus on the gut microbiota composition was assessed by shotgun metagenomic sequencing. RESULTS: Oral gavage of S thermophilus significantly reduced tumor formation in both Apcmin/+ and azoxymethane-injected mice. Coincubation with S thermophilus or its conditioned medium decreased the proliferation of cultured CRC cells. ß-Galactosidase was identified as the critical protein produced by S thermophilus by mass spectrometry screening and ß-galactosidase activity assay. ß-Galactosidase secreted by S thermophilus inhibited cell proliferation, lowered colony formation, induced cell cycle arrest, and promoted apoptosis of cultured CRC cells and retarded the growth of CRC xenograft. The mutant S thermophilus without functional ß-galactosidase lost its tumor-suppressive effect. Also, S thermophilus increased the gut abundance of known probiotics, including Bifidobacterium and Lactobacillus via ß-galactosidase. ß-Galactosidase-dependent production of galactose interfered with energy homeostasis to activate oxidative phosphorylation and downregulate the Hippo pathway kinases, which partially mediated the anticancer effects of S thermophilus. CONCLUSION: S thermophilus is a novel prophylactic for CRC prevention in mice. The tumor-suppressive effect of S thermophilus is mediated at least by the secretion of ß-galactosidase.

A surveillance method to identify patients with sepsis from electronic health records in Hong Kong: a single centre retrospective study.

BACKGROUND: Currently there are only two population studies on sepsis incidence in Asia. The burden of sepsis in Hong Kong is unknown. We developed a sepsis surveillance method to estimate sepsis incidence from a population electronic health record (EHR) in Hong Kong using objective clinical data. The study objective was to assess our method's performance in identifying sepsis using a retrospective cohort. We compared its accuracy to administrative sepsis surveillance methods such as Angus' and Martin's methods. METHOD: In this single centre retrospective study we applied our sepsis surveillance method on adult patients admitted to a tertiary hospital in Hong Kong. Two clinicians independently reviewed the clinical notes to determine which patients had sepsis. Performance was assessed by sensitivity, specificity, positive predictive value, negative predictive value and area under the curve (AUC) of Angus', Martin's and our surveillance methods using clinical review as "gold standard." RESULTS: Between January 1 and February 28, 2018, our sepsis surveillance method identified 1352 adult patients hospitalised with suspected infection. We found that 38.9% (95%CI 36.3-41.5) of these patients had sepsis. Using a 490 patient validation cohort, two clinicians had good agreement with weighted kappa of 0.75 (95% CI 0.69-0.81) before coming to consensus on diagnosis of uncomplicated infection or sepsis for all patients. Our method had sensitivity 0.93 (95%CI 0.89-0.96), specificity 0.86 (95%CI 0.82-0.90) and an AUC 0.90 (95%CI 0.87-0.92) when validated against clinician review. In contrast, Angus' and Martin's methods had AUCs 0.56 (95%CI 0.53-0.58) and 0.56 (95%CI 0.52-0.59), respectively. CONCLUSIONS: A sepsis surveillance method based on objective data from a population EHR in Hong Kong was more accurate than administrative methods. It may be used to estimate sepsis population incidence and outcomes in Hong Kong. TRIAL REGISTRATION: This study was retrospectively registered at clinicaltrials.gov on October 3, 2019 ( NCT04114214 ).

Association of NPAC score with survival after acute myocardial infarction.

BACKGROUND AND AIMS: Risk stratification in acute myocardial infarction (AMI) is important for guiding clinical management. Current risk scores are mostly derived from clinical trials with stringent patient selection. We aimed to establish and evaluate a composite scoring system to improve short-term mortality classification after index episodes of AMI, independent of electrocardiography (ECG) pattern, in a large real-world cohort. METHODS: Using electronic health records, patients admitted to our regional teaching hospital (derivation cohort, n = 1747) and an independent tertiary care center (validation cohort, n = 1276), with index acute myocardial infarction between January 2013 and December 2017, as confirmed by principal diagnosis and laboratory findings, were identified retrospectively. RESULTS: Univariate logistic regression was used as the primary model to identify potential contributors to mortality. Stepwise forward likelihood ratio logistic regression revealed that neutrophil-to-lymphocyte ratio, peripheral vascular disease, age, and serum creatinine (NPAC) were significant for 90-day mortality (Hosmer- Lemeshow test, p = 0.21). Each component of the NPAC score was weighted by beta-coefficients in multivariate analysis. The C-statistic of the NPAC score was 0.75, which was higher than the conventional Charlson's score (C-statistic = 0.63). Judicious application of a deep learning model to our dataset improved the accuracy of classification with a C-statistic of 0.81. CONCLUSIONS: The NPAC score comprises four items from routine laboratory parameters to basic clinical information and can facilitate early identification of cases at risk of short-term mortality following index myocardial infarction. Deep learning model can serve as a gatekeeper to facilitate clinical decision-making.

Cathelicidin preserves intestinal barrier function in polymicrobial sepsis.

OBJECTIVES: The intestinal epithelium compartmentalizes the sterile bloodstream and the commensal bacteria in the gut. Accumulating evidence suggests that this barrier is impaired in sepsis, aggravating systemic inflammation. Previous studies reported that cathelicidin is differentially expressed in various tissues in sepsis. However, its role in sepsis-induced intestinal barrier dysfunction has not been investigated. DESIGN: To examine the role of cathelicidin in polymicrobial sepsis, cathelicidin wild-(Cnlp+/+) and knockout (Cnlp-/-) mice underwent cecal-ligation and puncture (CLP) followed by the assessment of septic mortality and morbidity as well as histological, biochemical, immunological, and transcriptomic analyses in the ileal tissues. We also evaluated the prophylactic and therapeutic efficacies of vitamin D3 (an inducer of endogenous cathelicidin) in the CLP-induced murine polymicrobial sepsis model. RESULTS: The ileal expression of cathelicidin was increased by three-fold after CLP, peaking at 4 h. Knockout of Cnlp significantly increased 7-day mortality and was associated with a higher murine sepsis score. Alcian-blue staining revealed a reduced number of mucin-positive goblet cells, accompanied by reduced mucin expression. Increased number of apoptotic cells and cleavage of caspase-3 were observed. Cnlp deletion increased intestinal permeability to 4kD fluorescein-labeled dextran and reduced the expression of tight junction proteins claudin-1 and occludin. Notably, circulating bacterial DNA load increased more than two-fold. Transcriptome analysis revealed upregulation of cytokine/inflammatory pathway. Depletion of Cnlp induced more M1 macrophages and neutrophils compared with the wild-type mice after CLP. Mice pre-treated with cholecalciferol (an inactive form of vitamin D3) or treated with 1alpha, 25-dihydroxyvitamin D3 (an active form of VD3) had decreased 7-day mortality and significantly less severe symptoms. Intriguingly, the administration of cholecalciferol after CLP led to worsened 7-day mortality and the associated symptoms. CONCLUSIONS: Endogenous cathelicidin promotes intestinal barrier integrity accompanied by modulating the infiltration of neutrophils and macrophages in polymicrobial sepsis. Our data suggested that 1alpha, 25-dihydroxyvitamin D3 but not cholecalciferol is a potential therapeutic agent for treating sepsis.

Autophagy in intracellular bacterial infection.

Autophagy is a conserved intracellular degradation process enclosing the bulk of cytosolic components for lysosomal degradation to maintain cellular homeostasis. Accumulating evidences showed that a specialized form of autophagy, known as xenophagy, could serve as an innate immune response to defend against pathogens invading inside the host cells. Correspondingly, infectious pathogens have developed a variety of strategies to disarm xenophagy, leading to a prolonged and persistent intracellular colonization. In this review, we first summarize the current knowledge about the general mechanisms of intracellular bacterial infections and xenophagy. We then focus on the ongoing battle between these two processes.

PREhabilitation for improving QUality of recovery after ELective cardiac surgery (PREQUEL) study: protocol of a randomised controlled trial.

INTRODUCTION: Frailty is a multidimensional syndrome in which multiple small physiological deficits accumulate gradually, resulting in a loss of physiological reserve and adaptability, putting a patient that is exposed to a stressor at a higher risk of adverse outcomes. Both pre-frailty and frailty are associated with poor patient outcomes and higher healthcare costs. The effect of a prehabilitation programme and standard care on the quality of recovery in pre-frail and frail patients undergoing elective cardiac surgery will be compared. METHOD AND ANALYSIS: A single-centre, superiority, stratified randomised controlled trial with a blinded outcome assessment and intention-to-treat analysis. Pre-frail and frail patients awaiting elective coronary artery bypass graft, with or without valvular repair/replacement, will be recruited. 164 participants will be randomly assigned to either prehabilitation (intervention) or standard care (no intervention) groups. The prehabilitation group will attend two sessions/week of structured exercise (aerobic and resistance) training, supervised by a physiotherapist, for 6-10 weeks before surgery with early health promotion advice in addition to standard care. The standard care group will receive the usual routine care (no prehabilitation). Frailty will be assessed at baseline, hospital admission and at 1 and 3 months after surgery. The primary outcomes will be participants' perceived quality of recovery (15-item Quality of Recovery questionnaire) after surgery (day 3), days at home within 30 days of surgery and the changes in WHO Disability Assessment Schedule 2.0 score between baseline and at 1 and 3 months after surgery. Secondary outcomes will include major adverse cardiac and cerebrovascular events, psychological distress levels, health-related quality of life and healthcare costs. ETHICS AND DISSEMINATION: The Joint CUHK-NTEC Clinical Research Ethics Committee approved the study protocol (CREC Ref. No. 2017.696 T). The findings will be presented at scientific meetings, in peer-reviewed journals and to study participants. TRIAL REGISTRATION NUMBER: ChiCTR1800016098; Pre-results.

A Novel Peptide Interfering with proBDNF-Sortilin Interaction Alleviates Chronic Inflammatory Pain.

Rationale: Brain-derived neurotrophic factor (BDNF) is a key mediator in the development of chronic pain. Sortilin is known to interact with proBDNF and regulate its activity-dependent secretion in cortical neurons. In a rat model of inflammatory pain with intraplantar injection of complete Freund's adjuvant (CFA), we examined the functional role of proBDNF-sortilin interaction in dorsal root ganglia (DRG). Methods: Expression and co-localization of BDNF and sortilin were determined by immunofluorescence. ProBDNF-sortilin interaction interface was mapped using co-immunoprecipitation and bimolecular fluorescence complementation assay. The analgesic effect of intrathecal injection of a synthetic peptide interfering with proBDNF-sortilin interaction was measured in the CFA model. Results: BDNF and sortilin were co-localized and their expression was significantly increased in ipsilateral L4/5 DRG upon hind paw CFA injection. In vivo adeno-associated virus-mediated knockdown of sortilin-1 in L5 DRG alleviated pain-like responses. Mapping by serial deletions in the BDNF prodomain indicated that amino acid residues 71-100 supported the proBDNF-sortilin interaction. A synthetic peptide identical to amino acid residues 89-98 of proBDNF, as compared with scrambled peptide, was found to interfere with proBDNF-sortilin interaction, inhibit activity-dependent release of BDNF in vitro and reduce CFA-induced mechanical allodynia and heat hyperalgesia in vivo. The synthetic peptide also interfered with capsaicin-induced phosphorylation of extracellular signal-regulated kinases in ipsilateral spinal cord of CFA-injected rats. Conclusions: Sortilin-mediated secretion of BDNF from DRG neurons contributes to CFA-induced inflammatory pain. Interfering with proBDNF-sortilin interaction reduced activity-dependent release of BDNF and might serve as a therapeutic approach for chronic inflammatory pain.

The phytochemical polydatin ameliorates non-alcoholic steatohepatitis by restoring lysosomal function and autophagic flux.

Impaired autophagic degradation of intracellular lipids is causally linked to the development of non-alcoholic steatohepatitis (NASH). Pharmacological agents that can restore hepatic autophagic flux could therefore have therapeutic potentials for this increasingly prevalent disease. Herein, we investigated the effects of polydatin, a natural precursor of resveratrol, in a murine nutritional model of NASH and a cell line model of steatosis. Results showed that oral administration of polydatin protected against hepatic lipid accumulation and alleviated inflammation and hepatocyte damage in db/db mice fed methionine-choline deficient diet. Polydatin also alleviated palmitic acid-induced lipid accumulation in cultured hepatocytes. In both models, polydatin restored lysosomal function and autophagic flux that were impaired by NASH or steatosis. Mechanistically, polydatin inhibited mTOR signalling and up-regulated the expression and activity of TFEB, a known master regulator of lysosomal function. In conclusion, polydatin ameliorated NASH through restoring autophagic flux. The polydatin-regulated autophagy was associated with inhibition of mTOR pathway and restoration of lysosomal function by TFEB. Our study provided affirmative preclinical evidence to inform future clinical trials for examining the potential anti-NASH effect of polydatin in humans.

Exhaled air dispersion during high-flow nasal cannula therapy versus CPAP via different masks.

BACKGROUND: High-flow nasal cannula (HFNC) is an emerging therapy for respiratory failure but the extent of exhaled air dispersion during treatment is unknown. We examined exhaled air dispersion during HFNC therapy versus continuous positive airway pressure (CPAP) on a human patient simulator (HPS) in an isolation room with 16 air changes·h-1. METHODS: The HPS was programmed to represent different severity of lung injury. CPAP was delivered at 5-20 cmH2O via nasal pillows (Respironics Nuance Pro Gel or ResMed Swift FX) or an oronasal mask (ResMed Quattro Air). HFNC, humidified to 37°C, was delivered at 10-60 L·min-1 to the HPS. Exhaled airflow was marked with intrapulmonary smoke for visualisation and revealed by laser light-sheet. Normalised exhaled air concentration was estimated from the light scattered by the smoke particles. Significant exposure was defined when there was ≥20% normalised smoke concentration. RESULTS: In the normal lung condition, mean±sd exhaled air dispersion, along the sagittal plane, increased from 186±34 to 264±27 mm and from 207±11 to 332±34 mm when CPAP was increased from 5 to 20 cmH2O via Respironics and ResMed nasal pillows, respectively. Leakage from the oronasal mask was negligible. Mean±sd exhaled air distances increased from 65±15 to 172±33 mm when HFNC was increased from 10 to 60 L·min-1. Air leakage to 620 mm occurred laterally when HFNC and the interface tube became loose. CONCLUSION: Exhaled air dispersion during HFNC and CPAP via different interfaces is limited provided there is good mask interface fitting.