Early pathophysiology-driven airway pressure release ventilation versus low tidal volume ventilation strategy for patients with moderate-severe ARDS: study protocol for a randomized, multicenter, controlled trial.

BACKGROUND: Conventional Mechanical ventilation modes used for individuals suffering from acute respiratory distress syndrome have the potential to exacerbate lung injury through regional alveolar overinflation and/or repetitive alveolar collapse with shearing, known as atelectrauma. Animal studies have demonstrated that airway pressure release ventilation (APRV) offers distinct advantages over conventional mechanical ventilation modes. However, the methodologies for implementing APRV vary widely, and the findings from clinical studies remain controversial. This study (APRVplus trial), aims to assess the impact of an early pathophysiology-driven APRV ventilation approach compared to a low tidal volume ventilation (LTV) strategy on the prognosis of patients with moderate to severe ARDS. METHODS: The APRVplus trial is a prospective, multicenter, randomized clinical trial, building upon our prior single-center study, to enroll 840 patients from at least 35 hospitals in China. This investigation plans to compare the early pathophysiology-driven APRV ventilation approach with the control intervention of LTV lung-protective ventilation. The primary outcome measure will be all-cause mortality at 28 days after randomization in the intensive care units (ICU). Secondary outcome measures will include assessments of oxygenation, and physiology parameters at baseline, as well as on days 1, 2, and 3. Additionally, clinical outcomes such as ventilator-free days at 28 days, duration of ICU and hospital stay, ICU and hospital mortality, and the occurrence of adverse events will be evaluated. TRIAL ETHICS AND DISSEMINATION: The research project has obtained approval from the Ethics Committee of West China Hospital of Sichuan University (2019-337). Informed consent is required. The results will be submitted for publication in a peer-reviewed journal and presented at one or more scientific conferences. TRIAL REGISTRATION: The study was registered at Clinical Trials.gov (NCT03549910) on June 8, 2018.

Ferroptosis-related signature and immune infiltration characterization in acute lung injury/acute respiratory distress syndrome.

BACKGROUND: Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is one of the most life-threatening diseases in the intensive care unit with high mortality and morbidity. Ferroptosis is a newly discovered immune related cell death that is associated with various lung diseases. However, the role of immune-mediated ferroptosis in ALI/ARDS has not been elucidated. METHOD: We analyzed two Gene Expression Omnibus (GEO) datasets (GSE2411 and GSE109913) and extracted characteristic ferroptosis-related genes (FRGs) between the control and ALI groups through bioinformatic analysis. Then, we prospectively collected bronchoalveolar lavage fluid (BALF) from patients with ARDS and verified the expression of characteristic FRGs. Lastly, we constructed the ALI/ARDS model induced by LPS and isolated the primary neutrophils of mice. Erastin, an ferroptosis inducer, was used at the cellular level to verify the effect of neutrophils on ferroptosis in lung epithelium cells. RESULT: We identified three characteristic FRGs, Cp, Slc39a14 and Slc7a11, by analyzing two gene expression profiling datasets. Immune infiltration analysis showed that the three characteristic genes were significantly positively correlated with the infiltration levels of neutrophils. We collected BALF from 59 ARDS patients to verify the expression of Cp, Slc7a11 and Slc39a14 in humans. The results showed that Cp was elevated in patients with severe ARDS (p = 0.019), Slc7a11 was significantly elevated in patients with moderate ARDS (p = 0.021) relative to patients with mild ARDS. The levels of neutrophils in the peripheral blood of ARDS patients were positively correlated with the expression levels of Slc7a11 (Pearson's R2 = 0.086, p = 0.033). Three characteristic FRGs were significantly activated after the onset of ferroptosis (6 h) early in LPS induced ALI model, and that ferroptosis was alleviated after the organism compensated within 12 to 48 h. We extracted primary activated neutrophils from mice and co-cultured them with MLE-12 in transwell, Slc7a11, Cp and Slc39a14 in MLE-12 cells were significantly upregulated as the number of neutrophils increased. The results showed that neutrophil infiltration alleviated erastin-induced MDA accumulation, GSH depletion, and divalent iron accumulation, accompanied by upregulation of Slc7a11 and Gpx4, implying the existence of a compensatory effect of lipid oxidation in neutrophils after acute lung injury in the organism. CONCLUSION: We identified three immune-mediated ferroptosis genes, namely, Cp, Slc7a11 and Slc39a14, which possibly regulated by neutrophils during the development of ALI, and their pathways may be involved in anti-oxidative stress and anti-lipid metabolism. Thus, the present study contributes to the understanding of ALI/ARDS and provide novel targets for future immunotherapeutic.

SUMO and PIAS repress NF-κB activation in a basal chordate.

Small ubiquitin-like modifier (SUMO) regulates various biological processes, including the MyD88/TICAMs-IRAKs-TRAF6-NF-κB pathway, one of the core immune pathways. However, its functions are inconsistent between invertebrates and vertebrates and have rarely been investigated in lower chordates, including amphioxus and fishes. Here, we investigated the SUMOylation gene system in the amphioxus, a living basal chordate. We found that amphioxus has a SUMOylation system that has a complete set of genes and preserves several ancestral traits. We proceeded to study their molecular functions using the mammal cell lines. Both amphioxus SUMO1 and SUMO2 were shown to be able to attach to NF-κB Rel and to inhibit NF-κB activation by 50-75% in a dose-dependent fashion. The inhibition by SUMO2 could be further enhanced by the addition of the SUMO E2 ligase UBC9. In comparison, while human SUMO2 inhibited RelA, human SUMO1 slightly activated RelA. We also showed that, similar to human PIAS1-4, amphioxus PIAS could serve as a SUMO E3 ligase and promote its self-SUMOylation. This suggests that amphioxus PIAS is functionally compatible in human cells. Moreover, we showed that amphioxus PIAS is not only able to inhibit NF-κB activation induced by MyD88, TICAM-like, TRAF6 and IRAK4 but also able to suppress NF-κB Rel completely in the presence of SUMO1/2 in a dose-insensitive manner. This suggests that PIAS could effectively block Rel by promoting Rel SUMOylation. In comparison, in humans, only PIAS3, but not PIAS1/2/4, has been reported to promote NF-κB SUMOylation. Taken together, the findings from amphioxus, together with those from mammals and other species, not only offer insights into the functional volatility of the animal SUMO system, but also shed light on its evolutionary transitions from amphioxus to fish, and ultimately to humans.

Differential roles of the fish chitinous membrane in gut barrier immunity and digestive compartments.

The chitin-based peritrophic matrix (PM) is a structure critical for both gut immunity and digestion in invertebrates. PM was traditionally considered lost in all vertebrates, but a PM-like chitinous membrane (CM) has recently been discovered in fishes, which may increase the knowledge on vertebrate gut physiology and structural evolution. Here, we show that in zebrafish, the CM affects ingestion behavior, microbial homeostasis, epithelial renewal, digestion, growth, and longevity. Young mutant fish without CM appear healthy and are able to complete their life cycle normally, but with increasing age they develop gut inflammation, resulting in gut atrophy. Unlike mammals, zebrafish have no visible gel-forming mucin layers to protect their gut epithelia, but at least in young fish, the CM is not a prerequisite for the antibacterial gut immunity. These findings provide new insights into the role of the CM in fish prosperity and its eventual loss in tetrapods. These findings may also help to improve fish health and conservation, as well as to advance the understanding of vertebrate gut physiology and human intestinal diseases.

Clinical efficacy and safety of linezolid in intensive care unit patients.

Background: To characterize the population of critically ill patients and infections treated with linezolid in the intensive care unit (ICU), and to evaluate the clinical efficacy and safety of linezolid therapy. Methods: This multi-center, observational, real-world study was conducted across 52 hospitals between June 9, 2018, and December 28, 2019. Patients who met the following inclusion criteria were included: (1) admitted to the ICU, (2) of any age group, and (3) having a clinical or laboratory diagnosis of a Gram-positive bacterial infection. Clinical efficacy was categorized as success (cured or improved), failed, or non-evaluable. Adverse events and serious adverse events were recorded during treatment. Results: A total of 366 ICU patients who met the inclusion criteria were evaluated. Linezolid was used as second- and first-line treatment in 232 (63.4%) and 134 (36.6%) patients, respectively. The most common isolated strain was Staphylococcus aureus (methicillin-resistant Staphylococcus aureus: n=37/119, 31.1%; methicillin-susceptible Staphylococcus aureus: n=15/119, 12.6%); this was followed by Enterococci (vancomycin-resistant Enterococci: n=8/119, 6.7%; vancomycin-susceptible Enterococci: n=11/119, 9.2%) and Streptococcus pneumoniae (multidrug-resistant: n=4/119, 3.4%; non-multidrug resistant: n=2/119, 1.7%). The main infection sites where pathogens were detected included the lung (n=216/366, 59.6%), skin and soft tissue (n=104/366, 28.4%), and blood (n=50/366, 13.7%). Clinical success was achieved in 301 (82.2%) patients; 34 (9.3%) were cured and 267 (73.0%) improved; treatment failure and non-evaluable outcomes were observed in 29 (7.9%) in 36 (9.8%) patients, respectively. Linezolid-related adverse events were reported in 8 (2.2%) patients. No treatment-related serious adverse events were reported. Conclusions: Based on real-world results, linezolid was found to be effective and safe in the treatment of Gram-positive bacterial infections in critically ill patients.

Bridge-DNA synthesis triggered by an allosteric aptamer for the colorimetric detection of pathogenic bacteria.

Rapid and sensitive quantification of pathogenic bacteria is highly desired for environmental health supervision and food safety control. Yet, the amplification and detection of bacteria with a concentration lower than 102 cfu mL-1 remains a great challenge. Here, we combined an allosteric aptamer (AAP) with a gold nanoparticle (AuNP) for assembling a bridge-DNA synthesis system (named as AuNP-BDS) to amplify the bacterial signals. The AAP and its paired primer (PP) were covalently linked to two different AuNPs, respectively: one named as AAP-AuNP and the other PP-AuNP. Upon recognition of the antigen from the pathogenic bacteria, AAP alters its conformation to initiate DNA synthesis on the AuNP surface. The DNA products from AAP-AuNP and PP-AuNP form bridges to each other through base pairing, resulting in the aggregation and colorimetric response of the AuNPs. By using E. coli O157:H7 as an example, the AuNP-BDS could quantify pathogenic bacteria in water with a concentration as low as 10 cfu mL-1 within 60 min and without any enrichment. The colorimetric response values of AuNP-BDS were found to be linearly related to the bacterial concentrations in the range of 10 to 103 cfu mL-1. Good practicability of the AuNP-BDS in quantifying E. coli O157:H7 from tap water, juices, and milks was demonstrated. The AuNP-BDS could be exploited to facilitate the rapid and sensitive quantification of pathogenic bacteria for food safety control.

Effects of airway pressure release ventilation on multi-organ injuries in severe acute respiratory distress syndrome pig models.

BACKGROUND: Extra-pulmonary multi-organ failure in patients with severe acute respiratory distress syndrome (ARDS) is a major cause of high mortality. Our purpose is to assess whether airway pressure release ventilation (APRV) causes more multi-organ damage than low tidal volume ventilation (LTV). METHODS: Twenty one pigs were randomized into control group (n = 3), ARDS group (n = 3), LTV group (n = 8) and APRV group (n = 7). Severe ARDS model was induced by repeated bronchial saline lavages. Pigs were ventilated and monitored continuously for 48 h. Respiratory data, hemodynamic data, serum inflammatory cytokines were collected throughout the study. Histological injury and apoptosis were assessed by two pathologists. RESULTS: After severe ARDS modeling, pigs in ARDS, LTV and APRV groups experienced significant hypoxemia and reduced lung static compliance (Cstat). Oxygenation recovered progressively after 16 h mechanical ventilation (MV) in LTV and APRV group. The results of the repeated measures ANOVA showed no statistical difference in the PaO2/FiO2 ratio between the APRV and LTV groups (p = 0.54). The Cstat showed a considerable improvement in APRV group with statistical significance (p < 0.01), which was significantly higher than in the LTV group since 16 h (p = 0.04). Histological injury scores showed a significantly lower injury score in the middle and lower lobes of the right lung in the APRV group compared to LTV (pmiddle = 0.04, plower = 0.01), and no significant increase in injury scores for extra-pulmonary organs, including kidney (p = 0.10), small intestine (p = 1.0), liver (p = 0.14, p = 0.13) and heart (p = 0.20). There were no significant differences in serum inflammatory cytokines between the two groups. CONCLUSION: In conclusion, in the experimental pig models of severe ARDS induced by repetitive saline lavage, APRV improved lung compliance with reduced lung injury of middle and lower lobes, and did not demonstrate more extra-pulmonary organ injuries as compared with LTV.

Two novel mollusk short-form ApeC-containing proteins act as pattern recognition proteins for peptidoglycan.

The Apextrin C-terminal (ApeC) domain is a new protein domain largely specific to aquatic invertebrates. In amphioxus, a short-form ApeC-containing protein (ACP) family is capable of binding peptidoglycan (PGN) and agglutinating bacteria via its ApeC domain. However, the functions of ApeC in other phyla remain unknown. Here we examined 130 ACPs from gastropods and bivalves, the first and second biggest mollusk classes. They were classified into nine groups based on their phylogenetics and architectures, including three groups of short-form ACPs, one group of apextrins and two groups of ACPs of complex architectures. No groups have orthologs in other phyla and only four groups have members in both gastropods and bivalves, suggesting that mollusk ACPs are highly diversified. We selected one bivalve ACP (CgACP1; from the oyster Crossostrea gigas) and one gastropod ACP (BgACP1; from the snail Biomphalaria glabrata) for functional experiments. Both are highly-expressed, secreted short-form ACPs and hence comparable to the amphioxus ACPs previously reported. We found that recombinant CgACP1 and BgACP1 bound with yeasts and several bacteria with different affinities. They also agglutinated these microbes, but showed no inhibiting or killing effects. Further analyses show that both ACPs had high affinities to the Lys-type PGN from S. aureus but weak or no affinities to the DAP-type PGN from Bacillus subtilis. Both recombinant ACPs displayed weak or no affinities to other microbial cell wall components, including lipopolysaccharide (LPS), lipoteichoic acid (LTA), zymosan A, chitin, chitosan and cellulose, as well as to several PGN moieties, including muramyl dipeptide (MDP), N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc). Besides, CgACP1 had the highest expression in the gill and could be greatly up-regulated quickly after bacterial challenge. This is reminiscent of the amphioxus ACP1/2 which serve as essential mucus lectins in the gill. Taken together, the current findings from mollusk and amphioxus ACPs suggest several basic common traits for the ApeC domains, including the high affinity to Lys-type PGN, the bacterial binding and agglutinating capacity, and the role as mucus proteins to protect the mucosal surface.

The Effects of Airway Pressure Release Ventilation on Pulmonary Permeability in Severe Acute Respiratory Distress Syndrome Pig Models.

Objective: The aim of the study was to compare the effects of APRV and LTV ventilation on pulmonary permeability in severe ARDS. Methods: Mini Bama adult pigs were randomized into the APRV group (n = 5) and LTV group (n = 5). A severe ARDS animal model was induced by the whole lung saline lavage. Pigs were ventilated and monitored continuously for 48 h. Results: Compared with the LTV group, CStat was significantly better (p < 0.05), and the PaO2/FiO2 ratio showed a trend to be higher throughout the period of the experiment in the APRV group. The extravascular lung water index and pulmonary vascular permeability index showed a trend to be lower in the APRV group. APRV also significantly mitigates lung histopathologic injury determined by the lung histopathological injury score (p < 0.05) and gross pathological changes of lung tissues. The protein contents of occludin (p < 0.05), claudin-5 (p < 0.05), E-cadherin (p < 0.05), and VE-cadherin (p < 0.05) in the middle lobe of the right lung were higher in the APRV group than in the LTV group; among them, the contents of occludin (p < 0.05) and E-cadherin (p < 0.05) of the whole lung were higher in the APRV group. Transmission electron microscopy showed that alveolar-capillary barrier damage was more severe in the middle lobe of lungs in the LTV group. Conclusion: In comparison with LTV, APRV could preserve the alveolar-capillary barrier architecture, mitigate lung histopathologic injury, increase the expression of cell junction protein, improve respiratory system compliance, and showed a trend to reduce extravascular lung water and improve oxygenation. These findings indicated that APRV might lead to more profound beneficial effects on the integrity of the alveolar-capillary barrier architecture and on the expression of biomarkers related to pulmonary permeability.

HBx Mediated Increase of DDX17 Contributes to HBV-Related Hepatocellular Carcinoma Tumorigenesis.

HBV is strongly associated with HCC development and DEAD-box RNA helicase 17 (DDX17) is a very important member of the DEAD box family that plays key roles in HCC development by promoting cancer metastasis. However, the important role of DDX17 in the pathogenesis of HBV-related HCC remains unclear. In this study, we investigated the role of DDX17 in the replication of HBV and the development of HBV-associated HCC. Based on data from the GEO database and HBV-infected cells, we found that DDX17 was upregulated by the HBV viral protein X (HBx). Mechanistically, increased DDX17 expression promoted HBV replication and transcription by upregulating ZWINT. Further study showed that DDX17 could promote HBx-mediated HCC metastasis. Finally, the promotive effect of DDX17 on HBV and HBV-related HCC was confirmed in vivo. In summary, the results revealed the novel role of DDX17 in the replication of HBV and the metastasis of HBV-associated HCC.

SIRT2 Promotes HBV Transcription and Replication by Targeting Transcription Factor p53 to Increase the Activities of HBV Enhancers and Promoters.

Chronic hepatitis B (CHB) virus infection is one of the leading causes of cirrhosis and liver cancer. Although the major drugs against CHB including nucleos(t)ide analogs and PEG-interferon can effectively control human hepatitis B virus (HBV) infection, complete cure of HBV infection is quite rare. Targeting host factors involved in the viral life cycle contributes to developing innovative therapeutic strategies to improve HBV clearance. In this study, we found that the mRNA and protein levels of SIRT2, a class III histone deacetylase, were significantly upregulated in CHB patients, and that SIRT2 protein level was positively correlated with HBV viral load, HBsAg/HBeAg levels, HBcrAg, and ALT/AST levels. Functional analysis confirmed that ectopic SIRT2 overexpression markedly increased total HBV RNAs, 3.5-kb RNA and HBV core DNA in HBV-infected HepG2-Na+/taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, SIRT2 silencing inhibited HBV transcription and replication. In addition, we found a positive correlation between SIRT2 expression and HBV RNAs synthesis as well as HBV covalently closed circular DNA transcriptional activity. A mechanistic study suggested that SIRT2 enhances the activities of HBV enhancer I/HBx promoter (EnI/Xp) and enhancer II/HBc promoter (EnII/Cp) by targeting the transcription factor p53. The levels of HBV EnI/Xp and EnII/Cp-bound p53 were modulated by SIRT2. Both the mutation of p53 binding sites in EnI/Xp and EnII/Cp as well as overexpression of p53 abolished the effect of SIRT2 on HBV transcription and replication. In conclusion, our study reveals that, in terms of host factors, a SIRT2-targeted program might be a more effective therapeutic strategy for HBV infection.

Does airway pressure release ventilation offer new hope for treating acute respiratory distress syndrome?

Mechanical ventilation (MV) is an essential life support method for patients with acute respiratory distress syndrome (ARDS), which is one of the most common critical illnesses with high mortality in the intensive care unit (ICU). A lung-protective ventilation strategy based on low tidal volume (LTV) has been recommended since a few years; however, as this did not result in a significant decrease of ARDS-related mortality, a more optimal ventilation mode was required. Airway pressure release ventilation (APRV) is an old method defined as a continuous positive airway pressure (CPAP) with a brief intermittent release phase based on the open lung concept; it also perfectly fits the ARDS treatment principle. Despite this, APRV has not been widely used in the past, rather only as a rescue measure for ARDS patients who are difficult to oxygenate. Over recent years, with an increased understanding of the pathophysiology of ARDS, APRV has been reproposed to improve patient prognosis. Nevertheless, this mode is still not routinely used in ARDS patients given its vague definition and complexity. Consequently, in this paper, we summarize the studies that used APRV in ARDS, including adults, children, and animals, to illustrate the settings of parameters, effectiveness in the population, safety (especially in children), incidence, and mechanism of ventilator-induced lung injury (VILI) and effects on extrapulmonary organs. Finally, we found that APRV is likely associated with improvement in ARDS outcomes, and does not increase injury to the lungs and other organs, thereby indicating that personalized APRV settings may be the new hope for ARDS treatment.

Two Amphioxus ApeC-Containing Proteins Bind to Microbes and Inhibit the TRAF6 Pathway.

The apextrin C-terminal (ApeC) domain is a class of newly discovered protein domains with an origin dating back to prokaryotes. ApeC-containing proteins (ACPs) have been found in various marine and aquatic invertebrates, but their functions and the underlying mechanisms are largely unknown. Early studies suggested that amphioxus ACP1 and ACP2 bind to bacterial cell walls and have a role in immunity. Here we identified another two amphioxus ACPs (ACP3 and ACP5), which belong to the same phylogenetic clade with ACP1/2, but show distinct expression patterns and sequence divergence (40-50% sequence identities). Both ACP3 and ACP5 were mainly expressed in the intestine and hepatic cecum, and could be up-regulated after bacterial challenge. Both prokaryotic-expressed recombinant ACP3 and ACP5 could bind with several species of bacteria and yeasts, showing agglutinating activity but no microbicidal activity. ELISA assays suggested that their ApeC domains could interact with peptidoglycan (PGN), but not with lipoteichoic acid (LTA), lipopolysaccharides (LPS) and zymosan A. Furthermore, they can only bind to Lys-type PGN from Staphylococcus aureus, but not to DAP-type PGN from Bacillus subtilis and not to moieties of PGN such as MDPs, NAMs and NAGs. This recognition spectrum is different from that of ACP1/2. We also found that when expressed in mammalian cells, ACP3 could interact with TRAF6 via a conserved non-ApeC region, which inhibited the ubiquitination of TRAF6 and hence suppressed downstream NF-κB activation. This work helped define a novel subfamily of ACPs, which have conserved structures, and have related yet diversified molecular functions. Its members have dual roles, with ApeC as a lectin and a conserved unknown region as a signal transduction regulator. These findings expand our understanding of the ACP functions and may guide future research on the role of ACPs in different animal clades.

The neutrophil to lymphocyte ratio is an independent predictor for severe COVID-19 : Evidence from a multicenter case-control study and meta-analyses.

PURPOSE: The aim of this study was to determine whether the neutrophil to lymphocyte ratio (NLR) can predict severe Coronavirus disease 2019 (COVID-19). PATIENTS AND METHODS: A multicenter case-control study was conducted to investigate whether the NLR can help predict the severity of COVID-19. Patients confirmed to have COVID-19 between 16 January 2020 and 15 March 2020 were enrolled. Furthermore, meta-analyses were conducted based on both previous studies and our case-control study. RESULTS: In the case-control study, 213 patients (severe: 81) were included. The results suggested that the NLR was an independent risk factor (odds ratio [OR], 1.155, 95% confidence interval [95% CI]: 1.043-1.279, P = 0.006) and a great predictor (the area under the ROC curve was 0.728, 95% CI: 0.656-0.800) for severe COVID-19. In total, 18 datasets from 16 studies combined with our case-control study (severe: 1211; non-severe: 5838) were included in the meta-analyses and the results showed that the NLR of the severe COVID-19 group was significantly higher than that of the non-severe group (SMD = 1.10, 95% CI: 0.90-1.31, P < 0.001). Based on the 2â€¯× 2 data from 6 studies, the SROC of NLR for predicting severe COVID-19 was 0.802, with a sensitivity of 0.67 (95% CI: 0.61-0.72) and a specificity of 0.75 (95% CI: 0.73-0.78). CONCLUSION: Based on a multicenter case-control study and a meta-analysis, we found that the initial NLR was a great predictor of severe COVID-19.

[The role of respiratory therapists in the treatment of coronavirus disease 2019 patients in China].

OBJECTIVE: To investigate the clinical practice of Chinese respiratory therapists (RTs) participating in the treatment of coronavirus disease 2019 (COVID-19) patients and summarize the experience and role of RTs in the treatment of pandemic infectious diseases. METHODS: A self-designed questionnaire was used to investigate the RTs who treated COVID-19 patients in 31 provinces, cities and autonomous regions in China. The survey questionnaire included the basic work of RTs, the specific work of the treatment for COVID-19 patients and problems encountered at work. RESULTS: A total of 126 questionnaires were issued and 40 valid questionnaires were collected from RTs who treated COVID-19 patients at 22 COVID-19 designated hospitals in 8 provinces and municipalities. This included 7 hospitals in Wuhan, the epicenter of the epidemic. In their medical team, RTs accounted for 2.9% (1.5%, 6.7%) of medical staff, the working experience of the RTs was about (6.2±5.4) years, the ratio of RTs to beds was about 1:11 (1:5, 1:26), and 85.0% (34/40) of RTs were transferred from other hospitals. 97.5% (39/40) of RTs were involved in formulating individual respiratory care strategies in their medical teams, and they were all involved in the evaluation of respiratory care and decision-making as well as the early identification of deterioration of respiratory function. All RTs [100% (40/40)] indicated that they would actively monitor patients' respiratory status, increase the means and frequency of the monitoring, implement standardized oxygen therapy, prevent ventilator-associated lung injury (VALI), and standardize the management of artificial airway. However, less than 50% of RTs had carried out stress and strain, transpulmonary pressure, partial pressure of end-tidal carbon dioxide (PetCO2), end-expiratory lung volume, electrical impedance tomography (EIT) and other respiratory function monitoring. 85% of RTs conducted training and education related to respiratory care and formulated relevant standard operating procedures for their medical teams. More than 90% of RTs led the implementation of high-flow nasal cannula oxygen therapy (HFNC), pulmonary protective mechanical ventilation, prone ventilation, pulmonary rehabilitation, airway management, transfer of critical patients, and other respiratory treatment. CONCLUSIONS: RTs performed their professional role fully in the assessment, decision-making, and clinical practice in the treatment of COVID-19 patients. However, the manpower shortage of RTs is extremely prominent, the practical experience has provided the basis for the future treatment of infectious respiratory diseases and effectively promoted the development of respiratory care in China.

KAT2A Promotes Hepatitis B Virus Transcription and Replication Through Epigenetic Regulation of cccDNA Minichromosome.

Hepatitis B virus (HBV) infection remains a major health problem worldwide. Sufficient maintenance of the HBV covalently closed circular DNA (cccDNA), which serves as a template for HBV transcription, is responsible for the failure of antiviral therapies. While accumulating evidence suggests that cccDNA transcription is regulated by epigenetic machinery, particularly the acetylation and methylation of cccDNA-bound histone 3 (H3) and histone 4 (H4), the potential contributions of histone succinylation and related host factors remain obscured. Here, by screening a series of succinyltransferases and desuccinylases, we identified KAT2A as an important host factor of HBV transcription and replication. By using HBV-infected cells and mouse models with HBV infection, KAT2A was found to affect the transcriptional activity of cccDNA but did not affect cccDNA production. Mechanism studies showed that KAT2A is mainly located in the nucleus and could bind to cccDNA through interaction with HBV core protein (HBc). Moreover, we confirmed histone H3K79 succinylation (H3K79succ) as a histone modification on cccDNA minichromosome by using the cccDNA ChIP-Seq approach. Importantly, KAT2A silencing specifically reduced the level of cccDNA-bound succinylated H3K79. In conclusion, KAT2A promotes HBV transcription and replication through epigenetic machinery, and our findings may provide new insight into the treatment of HBV infection.

Broad distribution, high diversity and ancient origin of the ApeC-containing proteins.

Apextrin C-terminal (ApeC) is a novel protein domain with unknown functions, although early studies suggest that some ApeC-containing proteins (ACPs) bind to carbohydrates and have a role in development and immunity. Here we investigated the taxonomic distribution, sequence diversification and origin of ACPs in Metazoa. Most ACPs are present in invertebrates from aquatic or moist environments, including cnidarians, mollusks, echinoderms, cephalochordates, flatworms, water bears, nematodes and annelids. However, ACPs are absent in vertebrates and in most arthropod lineages (e.g. insects and crustaceans) except arachnids. ACPs apparently undergo rapid turnover and diversification, hence no orthologs could be found between (sub)phyla. ApeC can function either as a standalone domain or as a partner domain. It has been found to pair up with over ten different domain types in different ACPs. The partner domains are related to immunity, extracellular matrix, protein-protein and protein-carbohydrate interactions. Notably, the domain pair with the widest taxonomic distribution is MACPF/perforin-ApeC, which represent a classic group of ACPs called apextrins. ApeC also frequently pairs up with itself to form dual-ApeC modules in different phyla. Notably, in parasite flatworms, dual-ApeCs are present in 70% of ACPs and all inherited from a common ancestor. The broad distribution of MACPF-ApeC and dual-ApeC suggest their conserved yet unknown functions. We also discovered distant ApeC homologs in bacteria, hence tracing the origin of ApeC back to prokaryotes. Our findings show that ApeC has an ancient origin and is able to function alone or in complex domain architectures, though it is less prevalent than other versatile domains such as immunoglobulin domains and C-type lectin domains. This work provides a foundation for further functional study of this novel domain type.

[Association of Glucose Variability and ICU Delirium of Patients after Liver Transplantation].

OBJECTIVE: To study the association of glucose variability and ICU delirium of patients after liver transplantation. METHODS: This was a retrospective, single-center cohort study. Patients who admitted to ICU after liver transplantation during Aug. 2016 to Dec. 2018 were enrolled. They were divided into two groups accoding to whether they had delirium in ICU. Multivariate logistic regression analysis model was used to analyze the relationship between glucose variability and ICU delirium, and Cochran-Armitage trend test was used to analyze the linear relationship between blood glucose variability levels and the incidence of delirium. RESULTS: A total of 242 patients were enrolled, among them, 36 patients had delirium. The occurrence rate of delirium was 14.9% (36/242). Results indicated that glucose variability was an independently risk factor of ICU delirium for liver transplant patients ( P=0.045), and delirium was more common in patients with higher glucose variability (fourth quartile vs. first quartile, odds ratio =5.283, 95% confidence interval: 1.092～25.550, P=0.038). Results of Cochran-Armitage trend test indicated that there was a linear relationship between blood glucose variability level and ICU delirium rate, with the increase of glucose variability level, the risk of ICU delirium was increased too ( P<0.001). CONCLUSION: Glucose variability was an independently risk factor of ICU delirium in liver transplantation patients.

Neutrophil-to-lymphocyte ratio as a predictive biomarker for moderate-severe ARDS in severe COVID-19 patients.

TRIAL REGISTRATION: ChiCTR, ChiCTR2000029758. Registered 12 February 2020 - Retrospectively registered.

Functional Variation of IL-1R-Associated Kinases in the Conserved MyD88-TRAF6 Pathway during Evolution.

IL-1R-associated kinases (IRAK) are important regulators in the TLR/IL-1R pathways, but their function appears inconsistent between Drosophila, bony fishes, and vertebrates. This causes a difficulty to understand the IRAK functions. As a step to reveal the evolution of IRAKs, in this study, we performed comparative and functional analysis of IRAKs by exploiting the amphioxus, a pivotal taxon connecting invertebrates and vertebrates. Sequence and phylogenetic analysis indicated three major IRAK lineages: IRAK1/2/3 is a vertebrate-specific lineage, IRAK4 is an ancient lineage conserved between invertebrate and vertebrates, and Pelle is another ancient lineage that is preserved in protostomes and invertebrate deuterostomes but lost in vertebrate deuterostomes. Pelle is closer neither to IRAK4 nor to IRAK1/2/3, hence suggesting no clear functional analogs to IRAK1/2/3 in nonvertebrates. Functional analysis showed that both amphioxus IRAK4 and Pelle could suppress NF-κB activation induced by MyD88 and TRAF6, which are unlike mammalian and Drosophila IRAKs, but, surprisingly, similar to bony fish IRAK4. Also unlike Drosophila IRAKs, no interaction was detected between amphioxus IRAK4 and Pelle, although both of them were shown capable of binding MyD88. These findings, together with previous reports, show that unlike other signal transducers in the TLR/IL-1R pathways, such as MyD88 and TRAF6, the functions of IRAKs are highly variable during evolution and very specialized in different major animal taxa. Indeed, we suggest that the functional variability of IRAKs might confer plasticity to the signal transduction of the TLR/IL-1R pathways, which in return helps the species to evolve against the pathogens.