Lactate-lactylation-HSPA6 axis promotes PRRSV replication by impairing IFN-ß production.

Lactate, traditionally considered a metabolic by-product, has recently been identified as a substrate for the induction of lactylation, a newly identified epigenetic modification that plays an important role in the regulation of host gene expression. Our previous study showed that lactate levels were significantly elevated in cells infected with the porcine reproductive and respiratory syndrome virus (PRRSV), an Arterivirus that has devastated the swine industry worldwide for over 30 years. However, the role of elevated lactate in PRRSV infections remains unknown. In this study, we found that lactate was required for optimal PRRSV proliferation, and PRRSV infection increased cellular lactylation in a dose-dependent manner. Using the Cleavage Under Targets and Tagmentation (CUT&Tag) combined with RNA sequencing (RNA-seq) to screen the downstream genes regulated by lactylation in PRRSV-infected cells, we found that PRRSV-induced lactylation activated the expression of heat shock 70 kDa protein 6 (HSPA6). Follow-up experiments showed that HSPA6 is important for PRRSV proliferation by negatively modulating interferon (IFN)-ß induction. Mechanistically, HSPA6 impeded the interaction between TNF-receptor-associated factor 3 (TRAF3) and inhibitor of nuclear factor kappa-B kinase subunit epsilon (IKKε), thereby hindering the production of IFN-ß. Taken together, these results indicate that the activated lactate-lactylation-HSPA6 axis promotes viral growth by impairing IFN-ß induction, providing new therapeutic targets for the prevention and control of PRRSV infection. The results presented here also link lactylation to the virus life cycle, improving our understanding of epigenetic regulation in viral infection.IMPORTANCEAs a newly identified epigenetic modification, lactate-induced lactylation has received attentions because it plays important roles in gene expression and contributes to tumorigenesis and the innate immune response. Previous studies showed that many viruses upregulate cellular lactate levels; however, whether virus-elevated lactate induces lactylation and the subsequent biological significance of the modification to viral infection have not been reported. In this study, we demonstrated that porcine reproductive and respiratory syndrome virus (PRRSV) infection induced cellular lactylation, which, in turn, upregulated the expression of HSPA6, an IFN-negative regulator. We also dissected the mechanism by which HSPA6 negatively regulates IFN-ß production. To our knowledge, this is the first report to study virus-induced lactylation and establish the relationship between lactylation and virus infection.

Unfolding of an RNA G-quadruplex motif in the negative strand genome of porcine reproductive and respiratory syndrome virus by host and viral helicases to promote viral replication.

G-quadruplex (G4) is a unique secondary structure formed by guanine-rich nucleic acid sequences. Growing studies reported that the genomes of some viruses harbor G4 structures associated with viral replication, opening up a new field to dissect viral infection. Porcine reproductive and respiratory syndrome virus (PRRSV), a representative member of Arteriviridae, is an economically significant pathogen that has devastated the swine industry worldwide for over 30 years. In this study, we identified a highly conserved G-rich sequence with parallel-type G4 structure (named PRRSV-G4) in the negative strand genome RNA of PRRSV. Pyridostatin (PDS), a well-known G4-binding ligand, stabilized the PRRSV-G4 structure and inhibited viral replication. By screening the proteins interacting with PRRSV-G4 in PRRSV-infected cells and single-molecule magnetic tweezers analysis, we found that two helicases, host DDX18 and viral nsp10, interact with and efficiently unwound the PRRSV-G4 structure, thereby facilitating viral replication. Using a PRRSV reverse genetics system, we confirmed that recombinant PRRSV with a G4-disruptive mutation exhibited resistance to PDS treatment, thereby displaying higher replication than wild-type PRRSV. Collectively, these results demonstrate that the PRRSV-G4 structure plays a crucial regulatory role in viral replication, and targeting this structure represents a promising strategy for antiviral therapies.

Oncolytic vaccinia virus harboring aphrocallistes vastus lectin exerts anti-tumor effects by directly oncolysis and inducing immune response through enhancing ROS in human ovarian cancer.

Aphrocallistes vastus lectin (AVL) is a Ca2+ dependent C-type lectin produced by sponges. Previous studies have demonstrated that oncolytic vaccinia virus harboring AVL (oncoVV-AVL) effectively triggers cell death in various tumors. However, the effects of oncoVV-AVL on human ovarian cancer (OV) remain unknown. This study aims to investigate the mechanism-of-action of oncoVV-AVL in human OV cell lines and in tumor-bearing nude mice. We found that oncoVV-AVL could directly induce apoptosis and autophagy in ovarian cancer cells. Additionally, our results showed that oncoVV-AVL increased the serum levels of mouse IFN-γ (mIFN-γ), leading to the activation of M1-polarized macrophages. Conversely, NADPH, a reducing agent by providing reducing equivalents, reduced the production of mIFN-γ, and suppressed M1-polarization of macrophage. Based on these findings, we propose that oncoVV-AVL not only contributes to direct cytolysis, but also enhances host immune response by promoting ROS levels.

ROS Induced by Aphrocallistes vastus Lectin Enhance Oncolytic Vaccinia Virus Replication and Induce Apoptosis in Hepatocellular Carcinoma Cells.

Oncolytic virotherapy is expected to provide a new treatment strategy for cancer. Aphrocallistes vastus lectin (AVL) is a Ca2+-dependent lectin receptor containing the conserved domain of C-type lectin and the hydrophobic N-terminal region, which can bind to the bird's nest glycoprotein and D-galactose. Our previous studies suggested that the oncolytic vaccinia virus (oncoVV) armed with the AVL gene exerted remarkable replication and antitumor effects in vitro and in vivo. In this study, we found that oncoVV-AVL may reprogram the metabolism of hepatocellular carcinoma cells to promote ROS, and elevated ROS subsequently promoted viral replication and induced apoptosis. This study will provide a new theoretical basis for the application of oncoVV-AVL in liver cancer.

Cloning, expression of porcine GSDME and identification of its site cleaved by caspase-3.

As a member of the gasdermin family, gasdermin E (GSDME) is specifically cleaved by caspase-3, resulting in pyroptosis. To date, the biological characteristics and functions of human and mouse GSDME have been extensively studied; however, little is known of porcine GSDME (pGSDME). In this study, the full-length pGSDME-FL was cloned, which encodes 495 amino acids (aa) that have closely evolutionary relationships to the homolog of camelus, aquatic mammals, cattle and goat. Moreover, pGSDME was detected at different levels of expression in 21 tissues and 5 pig-derived cell lines tested by qRT-PCR, with the highest expression levels in mesenteric lymph nodes and PK-15 cell lines. Anti-pGSDME polyclonal antibody (pAb) with good specificity was generated by expressing the truncated recombinant protein pGSDME-1-208 and immunizing the rabbits. By western blot analysis using highly specific anti-pGSDME polyclonal antibody (pAb) prepared as primary antibody, it was not only confirmed that paclitaxel and cisplatin were positive stimuli to pGSDME cleavage and caspase-3 activation, but also identified the aspartate (D268) at position 268th of pGSDME as a cleavage site of caspase-3, and the overexpressed pGSDME-1-268 possesses cytotoxicity to HEK-293T cells, indicating that pGSDME-1-268 may contain active domains and involve pGSDME-mediated pyroptosis. These results lay a foundation for further investigating the function of pGSDME, especially its role in pyroptosis and its interaction with pathogens.

The Impact of Shared Decision-Making on the Quality of Decision Making in Aortic Dissection: A before-and-after Comparison Study.

Background: Complex surgical plans and consideration of risks and benefits often cause decisional conflicts for decision-makers in aortic dissection (AD) surgery, resulting in decision delay. Shared decision-making (SDM) improves decision readiness and reduces decisional conflicts. The purpose of this study was to investigate the impact of SDM on decision quality in AD. Methods: One hundred and sixty AD decision-makers were divided into two groups: control (n = 80) and intervention (n = 80). The surgical plan for the intervention group was determined using patient decision aids. The primary outcome was decisional conflict. Secondary outcomes included decision preparation, decision satisfaction, surgical method, postoperative complications, actual participation role, and duration of consultation. The data were analyzed with SPSS 26.0 (IBM Corp., Chicago, IL, USA). p < 0.05 was considered statistically significant. Results: The decisional conflict score was significantly lower in the intervention group than in the control group (p < 0.001). The decision preparation and decision satisfaction scores in the intervention group were significantly higher than those in the control group (p < 0.001). There were more SDM decision-makers in the intervention group (16 [20%] vs. 42 [52.50%]). There was no statistical significance in the choice of surgical, postoperative complications, duration of consultation, and hospital and post-operative intensive care unit stay time (p = 0.267, p = 0.130, p = 0.070, p = 0.397, p = 0.421, respectively). Income, education level, and residence were the influencing factors of decision-making conflict. Conclusions: SDM can reduce decisional conflict, improve decision preparation and satisfaction, and help decision-makers actively participate in the medical management of patients with AD without affecting the medical outcome.

A Comparative Study of Oncolytic Vaccinia Viruses Harboring Different Marine Lectins in Breast Cancer Cells.

Our previous studies demonstrated that arming vaccinia viruses with marine lectins enhanced the antitumor efficacy in several cancer cells. This study aims to compare the efficacy of oncolytic vaccinia viruses harboring Tachypleus tridentatus lectin (oncoVV-TTL), Aphrocallistes vastus lectin (oncoVV-AVL), white-spotted charr lectin (oncoVV-WCL), and Asterina pectinifera lectin (oncoVV-APL) in breast cancer cells (BC). These results indicated that oncoVV-AVL elicited the highest anti-tumor effect, followed by oncoVV-APL, while oncoVV-TTL and oncoVV-WCL had lower effects in BC. Further studies showed that apoptosis and replication may work together to enhance the cytotoxicity of oncoVV-lectins in a cell-type dependent manner. TTL/AVL/APL/WCL may mediate multiple pathways, including ERK, JNK, Hippo, and PI3K pathways, to promote oncoVV replication in MDA-MB-231 cells. In contrast, these pathways did not affect oncoVV-TTL/AVL/APL/WCL replication in MCF-7 cells, suggesting that the mechanisms of recombinant viruses in MCF-7 (ER+, PR+) and MDA-MB-231 (TNBC) cells were significantly different. Based on this study, we hypothesized that ER or PR may be responsible for the differences in promoting viral replication and inducing apoptosis between MCF-7 and MDA-MB-231 cells, but the specific mechanism needs to be further explored. In addition, small-molecule drugs targeting key cellular signaling pathways, including MAPK, PI3K/Akt, and Hippo, could be conjunction with oncoVV-AVL to promote breast cancer therapy, and key pathway factors in the JNK and PI3K pathways may be related to the efficacy of oncoVV-APL/TTL/WCL. This study provides a basis for applying oncolytic vaccinia virus in breast carcinoma.

Knowledge, attitude, and practice regarding postoperative delirium among cardiac surgery nurses: A cross-sectional multi-centre study.

AIMS AND OBJECTIVES: To examine knowledge, attitude, and practice regarding postoperative delirium and the relationships among cardiac surgery nurses in China. BACKGROUND: Postoperative delirium is a prevalent and devastating complication following cardiac surgery. Nurses play a part in multi-disciplinary collaboration for preventing and managing postoperative delirium, of whom knowledge, attitude, and practice are essential. DESIGN: A cross-sectional multi-centre study. METHODS: Nurses from cardiac surgery wards and intensive care units of five tertiary hospitals in Wuhan, Hubei Province, China were enrolled. Data were gathered online using a self-administered questionnaire. Student's t-test, or analysis of variance, or non-parametric tests were performed to compare differences across groups. Bootstrapping mediation analysis was conducted to examine the relationship between knowledge, attitude, and practice. The STROBE checklist was used for the reporting of this study. RESULTS: Of 429 nurses, a moderate level of knowledge and high levels of attitude and practice regarding postoperative delirium were revealed. Nurses with higher education, higher academic title, 5-10 years of practice in nursing and cardiac surgery nursing exhibited increased knowledge. With advanced age, practice in a specialised hospital, and training experience, nurses reported a better degree of practice. Attitude played a full mediating effect in the relationship between knowledge and practice, accounting for 81.82% of the total effects. CONCLUSIONS: Knowledge, attitude, and practice regarding postoperative delirium are promising among Chinese cardiac surgery nurses, with knowledge of screening tools and perioperative nonpharmacological interventions and practice of screening in need of enhancement. Attitudes act as an intermediary between knowledge and practice regarding postoperative delirium. RELEVANCE TO CLINICAL PRACTICE: Innovative and stratified in-service education is warranted to address knowledge enhancement. Meanwhile, organisations are suggested to make efforts to foster nurses' positive attitudes, particularly in creating a favourable culture and developing institutional protocols for postoperative delirium management to improve practice. NO PATIENT OR PUBLIC CONTRIBUTION: This study is focused on cardiac surgery nurses' knowledge, attitude, and practice regarding postoperative delirium, and the research questions and design are from clinical nursing practice, literature review, and expert panel review, in which the patient or public is temporarily not involved.

Effects of Oncolytic Vaccinia Viruses Harboring Different Marine Lectins on Hepatocellular Carcinoma Cells.

Oncolytic viruses are being developed as novel strategies for cancer therapy. Our previous studies have shown that vaccinia viruses armed with marine lectins improved the antitumor efficacy in diverse cancer types. The objective of this study was to assess the cytotoxic effects of oncoVV harboring Tachypleus tridentatus lectin (oncoVV-TTL), Aphrocallistes vastus lectin (oncoVV-AVL), white-spotted charr lectin (oncoVV-WCL), and Asterina pectinifera lectin (oncoVV-APL) on HCC. Our data revealed that the effects of recombinant viruses on Hep-3B cells were oncoVV-AVL > oncoVV-APL > oncoVV-TTL > oncoVV-WCL; oncoVV-AVL showed stronger cytotoxicity than oncoVV-APL, while oncoVV-TTL/WCL had no effect on cell killing in Huh7 cells, and PLC/PRF/5 cells exhibited sensitivity to oncoVV-AVL/TTL but not to oncoVV-APL/WCL. The cytotoxicity of oncoVV-lectins could be enhanced by apoptosis and replication in a cell-type-dependent manner. Further research revealed that AVL may mediate various pathways, including MAPK, Hippo, PI3K, lipid metabolism, and androgen pathways through AMPK crosstalk, to promote oncoVV replication in HCC in a cell-dependent manner. OncoVV-APL replication could be affected by AMPK/Hippo/lipid metabolism pathways in Hep-3B cells, AMPK/Hippo/PI3K/androgen pathways in Huh7 cells, and AMPK/Hippo pathways in PLC/PRF/5 cells. OncoVV-WCL replication was also multi-mechanistic, which could be affected by AMPK/JNK/lipid metabolism pathways in Hep-3B cells, AMPK/Hippo/androgen pathways in Huh7 cells, and AMPK/JNK/Hippo pathways in PLC/PRF/5 cells. In addition, AMPK and lipid metabolism pathways may play critical roles in oncoVV-TTL replication in Hep-3B cells, and oncoVV-TTL replication in Huh7 cells may depend on AMPK/PI3K/androgen pathways. This study provides evidence for the application of oncolytic vaccinia viruses in hepatocellular carcinoma.

[Postoperative Delirium in Patients on Cardiopulmonary Bypass for Cardiovascular Surgeries: Incidence and Influencing Factors].

Objective: To investigate the incidence and influencing factors of postoperative delirium (POD) and subsyndromal delirium (SSD) in patients connected to cardiopulmonary bypass during cardiovascular surgeries. Methods: We collected the general data and the data for the perioperative hematological, physiological, and biochemical indicators and the surgical and therapeutic conditions of patients connected to cardiopulmonary bypass during the course of cardiovascular surgeries conducted at a tertiary-care hospital in Hubei province between May 2022 and September 2022. The outcome indicators, including the incidence of POD and SSD, were assessed with the Nursing Delirium Screening Scale (Nu-DESC). Multinomial logistic regression was performed to analyze the influencing factors of patients with different statuses of POD and SSD. Results: Among the 202 patients, the incidence of SSD, SSD progressing to POD, and no POD or SSD (ND) progressing to POD were 13.4%, 6.4%, and 34.2%, respectively. Regression analysis showed that, with ND patients as the controls, the influencing factors for SSD were preoperative blood glucose (odds ratio [ OR]=0.38, 95% confidence interval [ CI]: 0.19-0.76), intraoperative platelet transfusion ( OR=0.37, 95% CI: 0.15-0.92), intraoperative etomidate ( OR=0.93, 95% CI: 0.87-0.98), and postoperative total bilirubin level ( OR=1.04, 95% CI: 1.01-1.07). For the progression of SSD to POD, the influencing factors were age ( OR=1.09, 95% CI: 1.01-1.17), ASA classification of IV and above ( OR=10.72, 95% CI: 1.85-62.08), intraoperative dexmedetomidine ( OR=1.01, 95% CI: 1.003-1.02), and the duration of mechanical ventilation ( OR=1.04, 95% CI: 1.01-1.07). For the progression of ND to POD, the influencing factors were age ( OR=1.06, 95% CI: 1.02-1.10), middle or high school education ( OR=0.35, 95% CI: 0.15-0.83), and the duration of mechanical ventilation ( OR=1.04, 95% CI: 1.01-1.07). Conclusion: Age, education, ASA classification, preoperative blood glucose, intraoperative platelet transfusion, intraoperative etomidate, intraoperative dexmedetomidine, postoperative total bilirubin, and the duration of mechanical ventilation are influencing factors for different statuses of POD and SSD among patients connected to cardiopulmonary bypass when they are undergoing cardiovascular surgeries. The influencing factors vary across groups of patients with different statuses of POD and SSD. Therefore, we should accurately assess the risk factors of patients with different statuses of POD and SSD and carry out corresponding interventions, thereby preventing or reducing the occurrence of POD and SSD, and ultimately promoting enhanced recovery after surgery.

Preliminary evaluation of the Chinese version of the patient-reported outcomes measurement information system 29-item profile in patients with aortic dissection.

BACKGROUND: The Patient-Reported Outcomes Measurement Information System 29-item Profile (PROMIS-29) has been widely used to measure health outcomes from the patient's perspective. It has not been validated in adults with aortic disease. The aim of this study was to explore the reliability and validity of the Chinese PROMIS-29 among patients undergoing surgery for aortic dissection (AD). METHODS: A cross-sectional design was applied. Eligible patients completed a questionnaire that contained the PROMIS-29 and legacy measures, including the Short Form-12 Health Survey (SF-12), 8-item Somatic Symptom Scale (SSS-8), Generalized Anxiety Disorder-2 (GAD-2), and Patient Health Questionnaire-2 (PHQ-2). The structural validity of the PROMIS-29 was evaluated using confirmatory factor analysis (CFA). Reliability was evaluated with Cronbach's α. Construct validity was assessed by calculating Spearman's rank correlations and comparing known-group differences. RESULTS: In total, a sample of 327 AD patients was included in the final analysis. Most of them were male (89%) with a mean age of 52.7 (± 10.3). CFA revealed good model fit of the seven-factor structure within PROMIS-29, as well as most domains in single-factor analysis. Reliability was confirmed with Cronbach's α > 0.90. Correlations between comparable domains of the PROMIS-29 and those of legacy questionnaires and most know-group comparisons were observed as hypothesized. CONCLUSIONS: This study found evidence for acceptable structural validity, construct validity and internal consistency of the PROMIS-29 in a sample of AD patients. It can be applied to AD survivors by researchers or clinicians, measuring outcomes after surgery and identifying those with worse health status.

Oncolytic Vaccinia Virus Harboring Aphrocallistes vastus Lectin Inhibits the Growth of Hepatocellular Carcinoma Cells.

Oncolytic vaccinia virus has been developed as a novel cancer therapeutic drug in recent years. Our previous studies demonstrated that the antitumor effect of oncolytic vaccina virus harboring Aphrocallistes vastus lectin (oncoVV-AVL) was significantly enhanced in several cancer cells. In the present study, we investigated the underlying mechanisms of AVL that affect virus replication and promote the antitumor efficacy of oncolytic virus in hepatocellular carcinoma (HCC). Our results showed that oncoVV-AVL markedly exhibited antitumor effects in both hepatocellular carcinoma cell lines and a xenograft mouse model. Further investigation illustrated that oncoVV-AVL could activate tumor immunity by upregulating the expression of type I interferons and enhance virus replication by inhibiting ISRE mediated viral defense response. In addition, we inferred that AVL promoted the ability of virus replication by regulating the PI3K/Akt, MAPK/ERK, and Hippo/MST pathways through cross-talk Raf-1, as well as metabolism-related pathways. These findings provide a novel perspective for the exploitation of marine lectins in oncolytic therapy.

Oncolytic Vaccinia Virus Carrying Aphrocallistes vastus Lectin (oncoVV-AVL) Enhances Inflammatory Response in Hepatocellular Carcinoma Cells.

Aphrocallistes vastus lectin (AVL) is a C-type marine lectin derived from sponges. Our previous study demonstrated that oncolytic vaccinia virus carrying AVL (oncoVV-AVL) significantly enhanced the cytotoxicity of oncoVV in cervical cancer, colorectal cancer and hepatocellular carcinoma through the activation of Ras/ERK, MAPK/ERK and PI3K/Akt signaling pathways. In this study, the inflammatory response induced by oncoVV-AVL in a hepatocellular carcinoma cell (HCC) model was investigated. The results showed that oncoVV-AVL increased the levels of inflammatory cytokines including IL-6, IL-8 and TNF-α through activating the AP-1 signaling pathway in HCC. This study provides novel insights into the utilization of lectin AVL in the field of cancer therapy.

Clinical nurses' moral courage and related factors: an empowerment perspective.

BACKGROUND: Moral courage as part of the moral competence of nurses has received increasing attention. Determination of the factors affecting moral courage is important in improving the quality of care. The purpose of this study was to investigate moral courage and related factors among frontline nurses from an empowerment perspective. METHODS: A cross-sectional study was conducted using data collection instruments comprising four main parts: the self-designed form of demographic characteristics, Conditions for Work Effectiveness II (CWEQ-II), Spreitzer's Psychological Empowerment Scale (PES) and Nurses' Moral Courage Scale (NMCS). Data were collected from 226 nurses in a tertiary hospital between February and March 2022 in Wuhan, the capital city of Hubei Province in central China. Descriptive statistics and multiple linear regression were used to analyze the data. RESULTS: The means of the total scores for the CWEQ-II, PES and the NMCS were 3.52 (SD = 0.69), 3.85 (SD = 0.53) and 3.90 (SD = 0.67), respectively. All the dimensions and the total scores of the CWEQ-II and PES were significantly correlated with the NMCS (p < 0.001). According to the multivariate stepwise regression analysis, CWEQ-II and PES were determined to be factors affecting NMCS. These variables explained 35.9% of the total variance in the moral courage scores of nurses. CONCLUSION: The level of moral courage among nurses is above average. Structural empowerment and psychological empowerment were the key factors affecting the promotion of moral courage. Hospital and organizational administrations should be conscious of the role of attach structural empowerment and psychological empowerment in the nursing workplace in increasing moral courage.

Porcine Deltacoronavirus nsp5 Cleaves DCP1A To Decrease Its Antiviral Activity.

Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus. The nonstructural protein nsp5, also called 3C-like protease, is responsible for processing viral polyprotein precursors in coronavirus (CoV) replication. Previous studies have shown that PDCoV nsp5 cleaves the NF-κB essential modulator and the signal transducer and activator of transcription 2 to disrupt interferon (IFN) production and signaling, respectively. Whether PDCoV nsp5 also cleaves IFN-stimulated genes (ISGs), IFN-induced antiviral effector molecules, remains unclear. In this study, we screened 14 classical ISGs and found that PDCoV nsp5 cleaved the porcine mRNA-decapping enzyme 1a (pDCP1A) through its protease activity. Similar cleavage of endogenous pDCP1A was also observed in PDCoV-infected cells. PDCoV nsp5 cleaved pDCP1A at glutamine 343 (Q343), and the cleaved pDCP1A fragments, pDCP1A1-343 and pDCP1A344-580, were unable to inhibit PDCoV infection. Mutant pDCP1A-Q343A, which resists nsp5-mediated cleavage, exhibited a stronger ability to inhibit PDCoV infection than wild-type pDCP1A. Interestingly, the Q343 cleavage site is highly conserved in DCP1A homologs from other mammalian species. Further analyses demonstrated that nsp5 encoded by seven tested CoVs that can infect human or pig also cleaved pDCP1A and human DCP1A, suggesting that DCP1A may be the common target for cleavage by nsp5 of mammalian CoVs.IMPORTANCE Interferon (IFN)-stimulated gene (ISG) induction through IFN signaling is important to create an antiviral state and usually directly inhibits virus infection. The present study first demonstrated that PDCoV nsp5 can cleave mRNA-decapping enzyme 1a (DCP1A) to attenuate its antiviral activity. Furthermore, cleaving DCP1A is a common characteristic of nsp5 proteins from different coronaviruses (CoVs), which represents a common immune evasion mechanism of CoVs. Previous evidence showed that CoV nsp5 cleaves the NF-κB essential modulator and signal transducer and activator of transcription 2. Taken together, CoV nsp5 is a potent IFN antagonist because it can simultaneously target different aspects of the host IFN system, including IFN production and signaling and effector molecules.

Natural Products from Actinomycetes Associated with Marine Organisms.

The actinomycetes have proven to be a rich source of bioactive secondary metabolites and play a critical role in the development of pharmaceutical researches. With interactions of host organisms and having special ecological status, the actinomycetes associated with marine animals, marine plants, macroalgae, cyanobacteria, and lichens have more potential to produce active metabolites acting as chemical defenses to protect the host from predators as well as microbial infection. This review focuses on 536 secondary metabolites (SMs) from actinomycetes associated with these marine organisms covering the literature to mid-2021, which will highlight the taxonomic diversity of actinomycetes and the structural classes, biological activities of SMs. Among all the actinomycetes listed, members of Streptomyces (68%), Micromonospora (6%), and Nocardiopsis (3%) are dominant producers of secondary metabolites. Additionally, alkaloids (37%), polyketides (33%), and peptides (15%) comprise the largest proportion of natural products with mostly antimicrobial activity and cytotoxicity. Furthermore, the data analysis and clinical information of SMs have been summarized in this article, suggesting that some of these actinomycetes with multiple host organisms deserve more attention to their special ecological status and genetic factors.

Structural Characterization and Heparanase Inhibitory Activity of Fucosylated Glycosaminoglycan from Holothuria floridana.

Unique fucosylated glycosaminoglycans (FG) have attracted increasing attention for various bioactivities. However, the precise structures of FGs usually vary in a species-specific manner. In this study, HfFG was isolated from Holothuria floridana and purified by anion exchange chromatography with the yield of ~0.9%. HfFG was composed of GlcA, GalNAc and Fuc, its molecular weight was 47.3 kDa, and the -OSO3-/-COO- molar ratio was 3.756. HfFG was depolymerized by a partial deacetylation-deaminative cleavage method to obtain the low-molecular-weight HfFG (dHfFG). Three oligosaccharide fragments (Fr-1, Fr-2, Fr-3) with different molecular weights were isolated from the dHfFG, and their structures were revealed by 1D and 2D NMR spectroscopy. HfFG should be composed of repeating trisaccharide units -{(L-FucS-α1,3-)d-GlcA-ß1,3-d-GalNAc4S6S-ß1,4-}-, in which sulfated fucose (FucS) includes Fuc2S4S, Fuc3S4S and Fuc4S residues linked to O-3 of GlcA in a ratio of 45:35:20. Furthermore, the heparanase inhibitory activities of native HfFG and oligosaccharide fragments (Fr-1, Fr-2, Fr-3) were evaluated. The native HfFG and its oligosaccharides exhibited heparanase inhibitory activities, and the activities increased with the increase of molecular weight. Additionally, structural characteristics such as sulfation patterns, the terminal structure of oligosaccharides and the presence of fucosyl branches may be important factors affecting heparanase inhibiting activity.

Porcine Reproductive and Respiratory Syndrome Virus Nonstructural Protein 4 Cleaves Porcine DCP1a To Attenuate Its Antiviral Activity.

As one of the most significant etiological agents in pigs, porcine reproductive and respiratory syndrome virus (PRRSV) has adversely impacted the global swine industry since it was discovered in the 1980s. The mRNA-decapping enzyme 1a (DCP1a), a regulatory factor involved in removing the 5'-methylguanosine cap from eukaryotic mRNA, has recently been identified as an IFN-stimulated gene. However, the role of DCP1a in PRRSV infection is not well understood. In this study, overexpression and knockdown of porcine DCP1a (pDCP1a) showed that pDCP1a affected PRRSV infection. Interestingly, we found that PRRSV infection significantly downregulated pDCP1a expression at the protein level by cleaving pDCP1a. Furthermore, we demonstrated that PRRSV nonstructural protein 4 (nsp4), a 3C-like proteinase, is responsible for pDCP1a cleavage, and the cleaved site is at glutamic acid 238 (E238) of pDCP1a. The mutant pDCP1a-E238A, which cannot be cleaved by nsp4, showed higher anti-PRRSV activity, and the antiviral effects of two cleavage products (pDCP1a1-238 and pDCP1a239-580) were significantly decreased compared with wild type pDCP1a. Unexpectedly, PRRSV infection or overexpression of nsp4 did not cleave monkey DCP1a, and monkey DCP1a showed a higher anti-PRRSV activity than pDCP1a. Taken together, this study reveals a new strategy evolved by PRRSV to dampen the host defense, complementing the known PRRSV-mediated immune evasion mechanisms.

Porcine Reproductive and Respiratory Syndrome Virus Infection Induces both eIF2α Phosphorylation-Dependent and -Independent Host Translation Shutoff.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an Arterivirus that has caused tremendous economic losses in the global swine industry since it was discovered in the late 1980s. Inducing host translation shutoff is a strategy used by many viruses to optimize their replication and spread. Here, we demonstrate that PRRSV infection causes host translation suppression, which is strongly dependent on viral replication. By screening PRRSV-encoded nonstructural proteins (nsps), we found that nsp2 participates in the induction of host translation shutoff and that its transmembrane (TM) domain is required for this process. nsp2-induced translation suppression is independent of protein degradation pathways and the phosphorylation of eukaryotic initiation factor 2α (eIF2α). However, the overexpression of nsp2 or its TM domain significantly attenuated the mammalian target of rapamycin (mTOR) signaling pathway, an alternative pathway for modulating host gene expression. PRRSV infection also attenuated the mTOR signaling pathway, and PRRSV-induced host translation shutoff could be partly reversed when the attenuated mTOR phosphorylation was reactivated by an activator of the mTOR pathway. PRRSV infection still negatively regulated the host translation when the effects of eIF2α phosphorylation were completely reversed. Taken together, our results demonstrate that PRRSV infection induces host translation shutoff and that nsp2 is associated with this process. Both eIF2α phosphorylation and the attenuation of the mTOR signaling pathway contribute to PRRSV-induced host translation arrest.IMPORTANCE Viruses are obligate parasites, and the production of progeny viruses relies strictly on the host translation machinery. Therefore, the efficient modulation of host mRNA translation benefits viral replication, spread, and evolution. In this study, we provide evidence that porcine reproductive and respiratory syndrome virus (PRRSV) infection induces host translation shutoff and that the viral nonstructural protein nsp2 is associated with this process. Many viruses induce host translation shutoff by phosphorylating eukaryotic initiation factor 2α (eIF2α). However, PRRSV nsp2 does not induce eIF2α phosphorylation but attenuates the mTOR signaling pathway, another pathway regulating the host cell translational machinery. We also found that PRRSV-induced host translation shutoff was partly reversed by eliminating the effects of eIF2α phosphorylation or reactivating the mTOR pathway, indicating that PRRSV infection induces both eIF2α phosphorylation-dependent and -independent host translation shutoff.

Enhancing peptaibols production in the biocontrol fungus Trichoderma longibrachiatum SMF2 by elimination of a putative glucose sensor.

Trichoderma spp. are main producers of peptide antibiotics known as peptaibols. While peptaibols have been shown to possess a range of biological activities, molecular understanding of the regulation of their production is largely unclear, which hampers the production improvement through genetic engineering. Here, we demonstrated that the orthologue of glucose sensors in the outstanding biocontrol fungus Trichoderma longibrachiatum SMF2, TlSTP1, participates in the regulation of peptaibols production. Deletion of Tlstp1 markedly impaired hyphal growth and conidiation, but significantly increased peptaibols yield by 5-fold for Trichokonins A and 2.6-fold for Trichokonins B. Quantitative real-time polymerase chain reaction analyses showed that the increased peptaibols production occurs at the transcriptional levels of the two nonribosomal peptide synthetase encoding genes, tlx1 and tlx2. Transcriptome analyses of the wild type and the Tlstp1 mutant strains indicated that TlSTP1 exerts a regulatory effect on a set of genes that are involved in a number of metabolic and cellular processes, including synthesis of several other secondary metabolites. These results suggest an important role of TlSTP1 in the regulation of vegetative growth and peptaibols production in T. longibrachiatum SMF2 and provide insights into construction of peptaibol-hyperproducing strains through genetic engineering.