Non-canonical regulation of the reactivation of an oncogenic herpesvirus by the OTUD4-USP7 deubiquitinases

Deubiquitinases (DUBs) remove ubiquitin from substrates and play crucial roles in diverse biological processes. However, our understanding of deubiquitination in viral replication remains limited. Employing an oncogenic human herpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV) to probe the role of protein deubiquitination, we found that Ovarian tumor family deubiquitinase 4 (OTUD4) promotes KSHV reactivation. OTUD4 interacts with the replication and transcription activator (K-RTA), a key transcription factor that controls KSHV reactivation, and enhances K-RTA stability by promoting its deubiquitination. Notably, the DUB activity of OTUD4 is not required for K-RTA stabilization; instead, OTUD4 functions as an adaptor protein to recruit another DUB, USP7, to deubiquitinate K-RTA and facilitate KSHV lytic reactivation. Our study has revealed a novel mechanism whereby KSHV hijacks OTUD4-USP7 deubiquitinases to promote lytic reactivation, which could be potentially harnessed for the development of new antiviral therapies.

Metabolic Enzymes in Viral Infection and Host Innate Immunity

Metabolic enzymes are central players for cell metabolism and cell proliferation. These enzymes perform distinct functions in various cellular processes, such as cell metabolism and immune defense. Because viral infections inevitably trigger host immune activation, viruses have evolved diverse strategies to blunt or exploit the host immune response to enable viral replication. Meanwhile, viruses hijack key cellular metabolic enzymes to reprogram metabolism, which generates the necessary biomolecules for viral replication. An emerging theme arising from the metabolic studies of viral infection is that metabolic enzymes are key players of immune response and, conversely, immune components regulate cellular metabolism, revealing unexpected communication between these two fundamental processes that are otherwise disjointed. This review aims to summarize our present comprehension of the involvement of metabolic enzymes in viral infections and host immunity and to provide insights for potential antiviral therapy targeting metabolic enzymes.

[Daratumumab maintenance after autologous hematopoietic stem cell transplantation for newly diagnosed multiple myeloma]

Objective: This study aimed to evaluate the efficacy and safety of daratumumab as a maintenance treatment after autologous hematopoietic stem cell transplantation (auto-HSCT) in patients with newly diagnosed multiple myeloma (NDMM) . Methods: The clinical data, hematological and renal response, and safety of 15 post-transplant patients with NDMM who had received daratumumab maintenance between May 1, 2022 and June 30, 2023 were retrospectively analyzed. Results: Fifteen patients (11 males and 4 females) with a median age of 58 (41-72) years were included. Thirteen patients did not receive daratumumab during induction therapy and auto-HSCT, 6 patients had renal impairment, and nine patients had high-risk cytogenetics. The median infusion of daratumumab was 12 (6-17) times, and the median duration of maintenance was 6 (1.5-12) months. The treatment efficacy was evaluated in all 15 patients, and daratumumab maintenance therapy increased the rate of stringent complete response from 40% to 60%. The renal response rate and median estimated glomerular filtration rate of six patients with RI-NDMM were also improved. During daratumumab maintenance therapy, the most common hematological grade 3 adverse event (AE) was lymphopenia [4 of 15 patients (26.67%) ], whereas the most common nonhematologic AEs were infusion-related reactions [7 of 15 patients (46.67%) ] and grade 3 pneumonia [5 of 15 patients (33.33%) ]. The five patients with pneumonia were daratumumab naive [5 of 13 patients (38.46%) ], with a median of 8 (6-10) infusions. Among them, the chest computed tomography of three patients showed interstitial infiltrates, and treatment with methylprednisolone was effective. With a median follow-up of 12 months, the 1-year overall survival rate was 93.33%, and only one patient died (which was not related to daratumumab treatment) . Conclusions: Daratumumab was safe and effective as a maintenance agent for post-auto-HSCT patients with NDMM, and AEs were controllable. The most common nonhematologic AE was grade 3 pneumonia, and a less dose-intense maintenance regimen for the first 8 weeks could reduce the incidence of pneumonia.

The Interferon-inducible NAMPT acts as a protein phosphoribosylase to restrict viral infection

As obligate intracellular pathogens, viruses often activate host metabolic enzymes to supply intermediates that support progeny production. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the salvage NAD+ synthesis, is an interferon-inducible protein that inhibits the replication of several RNA and DNA viruses with unknown mechanism. Here we report that NAMPT restricts herpes simplex virus 1 (HSV-1) replication via phosphoribosyl-hydrolase activity toward key viral structural proteins, independent of NAD+ synthesis. Deep mining of enriched phosphopeptides of HSV-1-infected cells identified phosphoribosylated viral structural proteins, particularly glycoproteins and tegument proteins. Indeed, NAMPT de-phosphoribosylates viral proteins in vitro and in cells. Chimeric and recombinant HSV-1 carrying phosphoribosylation-resistant mutations show that phosphoribosylation promotes the incorporation of structural proteins into HSV-1 virions and subsequent virus entry. Moreover, loss of NAMPT renders mice highly susceptible to HSV-1 infection. The work describes a hidden enzyme activity of a metabolic enzyme in viral infection and host defense, offering a system to interrogate roles of phosphoribosylation in metazoans.

The Apolipoprotein E neutralizing antibody inhibits SARS-CoV-2 infection by blocking cellular entry of lipoviral particles

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causal agent for coronavirus disease 2019 (COVID-19). Although vaccines have helped to prevent uncontrolled viral spreading, our understanding of the fundamental biology of SARS-CoV-2 infection remains insufficient, which hinders effective therapeutic development. Here, we found that Apolipoprotein E (ApoE), a lipid binding protein, is hijacked by SARS-CoV-2 for infection. Preincubation of SARS-CoV-2 with a neutralizing antibody specific to ApoE led to inhibition of SARS-CoV-2 infection. The ApoE neutralizing antibody efficiently blocked SARS-CoV-2 infection of human iPSC-derived astrocytes and air-liquid interface organoid models in addition to human ACE2-expressing HEK293T cells and Calu-3 lung cells. ApoE mediates SARS-CoV-2 entry through binding to its cellular receptors such as the low density lipoprotein receptor (LDLR). LDLR knockout or ApoE mutations at the receptor binding domain or an ApoE mimetic peptide reduced SARS-CoV-2 infection. Furthermore, we detected strong membrane LDLR expression on SARS-CoV-2 Spike-positive cells in human lung tissues, whereas no or low ACE2 expression was detected. This study provides a new paradigm for SARS-CoV-2 cellular entry through binding of ApoE on the lipoviral particles to host cell receptor(s). Moreover, this study suggests that ApoE neutralizing antibodies are promising antiviral therapies for COVID-19 by blocking entry of both parental virus and variants of concern.

Locoregional radiotherapy improves survival outcomes in de novo metastatic nasopharyngeal carcinoma treated with chemoimmunotherapy

BACKGROUND

We aimed to investigate the efficacy of locoregional radiotherapy (LRRT) in patients with de novo metastatic nasopharyngeal carcinoma (dmNPC) receiving chemotherapy combined with anti-programmed cell death receptor-1 monoclonal antibodies (anti-PD-1 mAbs) as first-line treatment and identify optimal candidates for LRRT.

MATERIALS AND METHODS

We enrolled patients with dmNPC receiving platinum-based palliative chemotherapy and anti-PD-1 mAbs followed or not followed by LRRT from four centers. The endpoints were progression-free survival (PFS), objective response rate (ORR), and overall survival (OS). We used the inverse probability of treatment weighting (IPTW) to balance the baseline characteristics of the LRRT and non-LRRT groups to minimize selection bias before comparative analyses. Multivariate analyses were carried out using the Cox proportional hazards model.

RESULTS

We included 163 patients with dmNPC (median follow-up: 22 months). The median PFS was 20 months, and the ORR was 92.0%; the median OS was not achieved. After IPTW adjustments, patients who received LRRT had a significant survival benefit over those not receiving LRRT (median PFS: 28 versus 15 months, P < 0.001). The Epstein-Barr virus DNA (EBV DNA) level after four to six cycles of anti-PD-1 mAbs [weighted hazard ratio (HR): 2.19, 95% confidence interval (CI) 1.22-3.92, P = 0.008] and LRRT (weighted HR: 0.58, 95% CI 0.34-0.99, P = 0.04) were independent prognostic factors. Patients with undetectable EBV DNA levels after four to six cycles of anti-PD-1 mAbs (early EBV DNA clearance) benefitted from LRRT (HR: 0.41, 95% CI 0.22-0.79, P = 0.008), whereas those with detectable levels did not (HR: 1.30, 95% CI 0.59-2.87, P = 0.51).

CONCLUSIONS

Palliative chemotherapy combined with anti-PD-1 mAbs followed by LRRT was associated with improved PFS in patients with dmNPC, especially for patients with early EBV DNA clearance.

Alkyne as a Latent Warhead to Covalently Target SARS-CoV-2 Main Protease

There is an urgent need for improved therapy to better control the ongoing COVID-19 pandemic. The main protease Mpro plays a pivotal role in SARS-CoV-2 replications, thereby representing an attractive target for antiviral development. We seek to identify novel electrophilic warheads for efficient, covalent inhibition of Mpro. By comparing the efficacy of a panel of warheads installed on a common scaffold against Mpro, we discovered that the terminal alkyne could covalently modify Mpro as a latent warhead. Our biochemical and X-ray structural analyses revealed the irreversible formation of the vinyl-sulfide linkage between the alkyne and the catalytic cysteine of Mpro. Clickable probes based on the alkyne inhibitors were developed to measure target engagement, drug residence time, and off-target effects. The best alkyne-containing inhibitors potently inhibited SARS-CoV-2 infection in cell infection models. Our findings highlight great potentials of alkyne as a latent warhead to target cystine proteases in viruses and beyond.

Mechanistic insights into the role of herpes simplex virus 1 in Alzheimer's disease

Alzheimer's Disease (AD) is an aging-associated neurodegenerative disorder, threatening millions of people worldwide. The onset and progression of AD can be accelerated by environmental risk factors, such as bacterial and viral infections. Human herpesviruses are ubiquitous infectious agents that underpin numerous inflammatory disorders including neurodegenerative diseases. Published studies concerning human herpesviruses in AD imply an active role HSV-1 in the pathogenesis of AD. This review will summarize the current understanding of HSV-1 infection in AD and highlight some barriers to advance this emerging field.

METTL16 controls Kaposi's sarcoma-associated herpesvirus replication by regulating S-adenosylmethionine cycle

Oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV) consists of latent and lytic replication phases, both of which are important for the development of KSHV-related cancers. As one of the most abundant RNA modifications, N6-methyladenosine (m6A) and its related complexes regulate KSHV life cycle. However, the role of METTL16, a newly discovered RNA methyltransferase, in KSHV life cycle remains unknown. In this study, we have identified a suppressive role of METTL16 in KSHV lytic replication. METTL16 knockdown increased while METTL16 overexpression reduced KSHV lytic replication. METTL16 binding to and writing of m6A on MAT2A transcript are essential for its splicing, maturation and expression. As a rate-limiting enzyme in the methionine-S-adenosylmethionine (SAM) cycle, MAT2A catalyzes the conversion of L-methionine to SAM required for the transmethylation of protein, DNA and RNA, transamination of polyamines, and transsulfuration of cystathionine. Consequently, knockdown or chemical inhibition of MAT2A reduced intracellular SAM level and enhanced KSHV lytic replication. In contrast, SAM treatment was sufficient to inhibit KSHV lytic replication and reverse the effect of the enhanced KSHV lytic program caused by METTL16 or MAT2A knockdown. Mechanistically, METTL16 or MAT2A knockdown increased while SAM treatment decreased the intracellular reactive oxygen species level by altering glutathione level, which is essential for efficient KSHV lytic replication. These findings demonstrate that METTL16 suppresses KSHV lytic replication by modulating the SAM cycle to maintain intracellular SAM level and redox homeostasis, thus illustrating the linkage of KSHV life cycle with specific m6A modifications, and cellular metabolic and oxidative conditions.

STING is a cell-intrinsic metabolic checkpoint restricting aerobic glycolysis by targeting HK2

Evasion of antitumour immunity is a hallmark of cancer. STING, a putative innate immune signalling adaptor, has a pivotal role in mounting antitumour immunity by coordinating innate sensing and adaptive immune surveillance in myeloid cells. STING is markedly silenced in various human malignancies and acts as a cell-intrinsic tumour suppressor. How STING exerts intrinsic antitumour activity remains unclear. Here, we report that STING restricts aerobic glycolysis independent of its innate immune function. Mechanistically, STING targets hexokinase II (HK2) to block its hexokinase activity. As such, STING inhibits HK2 to restrict tumour aerobic glycolysis and promote antitumour immunity in vivo. In human colorectal carcinoma samples, lactate, which can be used as a surrogate for aerobic glycolysis, is negatively correlated with STING expression level and antitumour immunity. Taken together, this study reveals that STING functions as a cell-intrinsic metabolic checkpoint that restricts aerobic glycolysis to promote antitumour immunity. These findings have important implications for the development of STING-based therapeutic modalities to improve antitumour immunotherapy.

Genome-Wide CRISPR-Cas9 Screen Identifies SMCHD1 as a Restriction Factor for Herpesviruses

Intrinsic immunity is the frontline of host defense against invading pathogens. To combat viral infection, mammalian hosts deploy cell-intrinsic effectors to block viral replication prior to the onset of innate and adaptive immunity. In this study, SMCHD1 is identified as a pivotal cellular factor that restricts Kaposi's sarcoma-associated herpesvirus (KSHV) lytic reactivation through a genome-wide CRISPR-Cas9 knockout screen. Genome-wide chromatin profiling revealed that SMCHD1 associates with the KSHV genome, most prominently the origin of lytic DNA replication (ORI-Lyt). SMCHD1 mutants defective in DNA binding could not bind ORI-Lyt and failed to restrict KSHV lytic replication. Moreover, SMCHD1 functioned as a pan-herpesvirus restriction factor that potently suppressed a wide range of herpesviruses, including alpha, beta, and gamma subfamilies. SMCHD1 deficiency facilitated the replication of a murine herpesvirus in vivo. These findings uncovered SMCHD1 as a restriction factor against herpesviruses, and this could be harnessed for the development of antiviral therapies to limit viral infection. IMPORTANCE Intrinsic immunity represents the frontline of host defense against invading pathogens. However, our understanding of cell-intrinsic antiviral effectors remains limited. In this study, we identified SMCHD1 as a cell-intrinsic restriction factor that controlled KSHV lytic reactivation. Moreover, SMCHD1 restricted the replication of a wide range of herpesviruses by targeting the origins of viral DNA replication (ORIs), and SMCHD1 deficiency facilitated the replication of a murine herpesvirus in vivo. This study helps us to better understand intrinsic antiviral immunity, which may be harnessed to develop new therapeutics for the treatment of herpesvirus infection and the related diseases.

[A cross-sectional survey on the allocation of nursing human resources in burn centers in China]

Objective: To investigate the allocation of nursing human resources in burn centers in China. Methods: A cross-sectional survey was conducted. Using a self-designed questionnaire, a survey was carried out from January to March 2022 to investigate the January to December 2021 status of 39 burn centers in China that met the inclusion criteria based on six strategic regions and other regions, including the hospital grade and the region, the number of nurses and opening beds in the burn centers and burn intensive care units (BICUs), the age, working seniority in burn specialty, educational background, professional title, personnel employment, and turnover of nurses and training of newly recruited nurses in the burn centers. Results: This survey covered 30 provinces, municipalities, and autonomous regions in China (excluding Hong Kong Special Administrative Region, Macao Special Administrative Region, and Taiwan region of China). A total of 39 questionnaires were collected, all of which were valid. The 39 burn centers were located in 38 tertiary A hospitals and 1 tertiary B hospital, with 26 burn centers in strategic areas. The nurse/bed ratio of burn centers in the Greater Bay Area of Guangdong, Hong Kong, and Macao was the highest, while the nurse/bed ratio of burn centers in border ethnic minority area was the lowest. Except for the Chengdu-Chongqing Economic Circle, BICUs had been set up in burn centers in other regions. Among the 39 burn centers, the percentage of nurses aged 25 to 34 years was 51.21% (738/1 441), the percentage of nurses worked in burn specialty for less than 5 years was 31.16% (449/1 441), the percentage of nurses with bachelor's degree was 69.74% (1 005/1 441), and the percentage of nurses with nursing professional title was 44.14% (636/1 441), which were the highest. There were significant differences in the employment of nurses, the percentage of permanent nurses in burn centers in the collaborative development zone of Beijing-Tianjin-Hebei was 82.48% (113/137), while the percentage of permanent nurses in burn centers in important military strategic area was only 9.42% (34/361); the turnover rate of nurses was 9.03% (143/1 584), among which the turnover rate of nurses was 18.14% (80/441) in burn centers in important military strategic area. The training for newly recruited nurses in 39 burn centers was mainly based on the guidance of senior nurses and the pre-job education+specialist training. Conclusions: The burn nursing human resources in strategic areas in China are seriously insufficient and unevenly distributed, with unstable nurse team and lack of standardized specialist training. In particular, the nursing human resources in BICUs need to be equipped and supplemented urgently.

Factor Xa cleaves SARS-CoV-2 spike protein to block viral entry and infection

Serine proteases (SP), including furin, trypsin, and TMPRSS2 cleave the SARS-CoV-2 spike (S) protein, enabling the virus to enter cells. Here, we show that factor (F) Xa, an SP involved in blood coagulation, is upregulated in COVID-19 patients. In contrast to other SPs, FXa exerts antiviral activity. Mechanistically, FXa cleaves S protein, preventing its binding to ACE2, and thus blocking viral entry and infection. However, FXa is less effective against variants carrying the D614G mutation common in all pandemic variants. The anticoagulant rivaroxaban, a direct FXa inhibitor, inhibits FXa-mediated S protein cleavage and facilitates viral entry, whereas the indirect FXa inhibitor fondaparinux does not. In the lethal SARS-CoV-2 K18-hACE2 model, FXa prolongs survival yet its combination with rivaroxaban but not fondaparinux abrogates that protection. These results identify both a previously unknown function for FXa and an associated antiviral host defense mechanism against SARS-CoV-2 and suggest caution in considering direct FXa inhibitors for preventing or treating thrombotic complications in COVID-19 patients.

STeerING PI4P for innate immune activation

STING transverses the endoplasmic reticulum (ER), Golgi, and endosomal compartments before its degradation within the lysosomes. In this issue of Immunity, Fang et al. demonstrate that the enrichment of cholesterol and sphingomyelin in the trans-Golgi network and endosomes mediated by the ARMH3-PI4KB-PI4P pathway plays a pivotal role in STING activation under cGAS-dependent and -independent conditions.

Potent NKT cell ligands overcome SARS-CoV-2 immune evasion to mitigate viral pathogenesis in mouse models

One of the major pathogenesis mechanisms of SARS-CoV-2 is its potent suppression of innate immunity, including blocking the production of type I interferons. However, it is unknown whether and how the virus interacts with different innate-like T cells, including NKT, MAIT and γδ T cells. Here we reported that upon SARS-CoV-2 infection, invariant NKT (iNKT) cells rapidly trafficked to infected lung tissues from the periphery. We discovered that the envelope (E) protein of SARS-CoV-2 efficiently down-regulated the cell surface expression of the antigen-presenting molecule, CD1d, to suppress the function of iNKT cells. E protein is a small membrane protein and a viroporin that plays important roles in virion packaging and envelopment during viral morphogenesis. We showed that the transmembrane domain of E protein was responsible for suppressing CD1d expression by specifically reducing the level of mature, post-ER forms of CD1d, suggesting that it suppressed the trafficking of CD1d proteins and led to their degradation. Point mutations demonstrated that the putative ion channel function was required for suppression of CD1d expression and inhibition of the ion channel function using small chemicals rescued the CD1d expression. Importantly, we discovered that among seven human coronaviruses, only E proteins from highly pathogenic coronaviruses including SARS-CoV-2, SARS-CoV and MERS suppressed CD1d expression, whereas the E proteins of human common cold coronaviruses, HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1, did not. These results suggested that E protein-mediated evasion of NKT cell function was likely an important pathogenesis factor, enhancing the virulence of these highly pathogenic coronaviruses. Remarkably, activation of iNKT cells with their glycolipid ligands, both prophylactically and therapeutically, overcame the putative viral immune evasion, significantly mitigated viral pathogenesis and improved host survival in mice. Our results suggested a novel NKT cell-based anti-SARS-CoV-2 therapeutic approach.

Ultralight type I transvaginal mesh: an alternative for recurrent severe posterior vaginal prolapse

OBJECTIVE

This study aimed to analyze the medium-term outcomes of ultralight type I mesh for postmenopausal women with recurrent severe posterior vaginal prolapse (PVP).

METHODS

All participants underwent transvaginal ultralight type I mesh repair between April 2016 and April 2021 and were followed until May 2022. Pelvic Organ Prolapse Quantification System (POP-Q) staging, mesh-related complications, Patient Global Impression of Improvement (PGI-I) scale and quality of life questionnaire responses were evaluated. The primary outcome was composite surgical success rate at the last follow-up, composite success being defined as no vaginal bulge symptoms, no POP-Q point at or beyond the hymen and no re-treatment for POP. Secondary outcomes included anatomic outcomes (POP-Q score), symptomatic relief and complications.

RESULTS

The median follow-up was 37.3 months. At the last follow-up, the composite success rate was 75%, and POP-Q scores for the vault and posterior wall and quality of life questionnaire scores were significantly improved (p < 0.01). The subjective satisfaction (PGI-I ≤ 2) rate was 83.3%. There were no mesh-related complications.

CONCLUSIONS

Ultralight mesh can achieve good clinical outcomes and substantially improve the quality of life of patients with severe recurrent PVP in the medium term, and may thus be a viable alternative for treating this condition.

Early pregnancy regulates the expression of prolactin and its receptor in the thymus, the liver, the spleen and lymph nodes in sheep

As a pituitary hormone, prolactin (PRL) is also synthesized by immune system cells, and exerts its effects on the immune system by binding to its receptor (PRLR) via endocrine and paracrine/autocrine pathways. The immune organs adapt to the presence of fetal alloantigens during pregnancy, and the immune system is composed of primary organs and secondary organs. The objective of this study is to analyze the effects of early pregnancy on expression of PRL and PRLR in maternal immune organs in sheep. In this study, the thymus, lymph node, the spleen and the liver were sampled at day 16 of the estrous cycle, and at days 13, 16, and 25 of pregnancy in ewes. Expression of PRL and PRLR was analyzed through quantitative real-time PCR, Western blot and immunohistochemistry. Our data showed that there were an upregulation of PRL and PRLR in the thymus, lymph node and the spleen, and a downregulation in the liver during early pregnancy in ewes. In conclusion, it is reported for the first time that early pregnancy has tissue specific effects on expression of PRL isoform and PRLR isoform in the thymus, lymph node, the spleen and the liver, which may be owing to these organs exerting different functions during early pregnancy, and necessary for the successful pregnancy in sheep.

Impacts of menopause hormone therapy on mood disorders among postmenopausal women

OBJECTIVE

This study aimed to explore the modulatory effects of menopause hormone therapy (MHT) on mood disorders among postmenopausal women.

METHODS

A cross-sectional study was conducted to recruit postmenopausal women, including patients (arranged MHT for over 3 years as the medication group) and non-MHT controls. All participants were asked to respond to the Center for Epidemiological Studies Depression Scale (CES-D) and Generalized Anxiety Disorder Screener (GAD-7) questionnaires to assess their depression and anxiety status.

RESULTS

A total of 230 cases from the two groups were determined based on propensity score matching analysis by matching the menopausal age and menopausal durations. We found that MHT served as a favorable modulator in the depression status of postmenopausal women. Among the four factors of the CES-D questionnaire, our data indicated that the differences between the two groups fell primarily into two aspects: depressive emotion, and somatic symptoms or retarded activities. MHT was mainly involved in improving the depression of overweight women. However, no substantial effects of MHT were observed on the regulation of anxiety.

CONCLUSION

Postmenopausal women, especially the overweight population, who have experienced MHT exhibited an improved depressive status but not their anxiety condition.

The roles of APOBEC-mediated RNA editing in SARS-CoV-2 mutations, replication and fitness

During COVID-19 pandemic, mutations of SARS-CoV-2 produce new strains that can be more infectious or evade vaccines. Viral RNA mutations can arise from misincorporation by RNA-polymerases and modification by host factors. Analysis of SARS-CoV-2 sequence from patients showed a strong bias toward C-to-U mutation, suggesting a potential mutational role by host APOBEC cytosine deaminases that possess broad anti-viral activity. We report the first experimental evidence demonstrating that APOBEC3A, APOBEC1, and APOBEC3G can edit on specific sites of SARS-CoV-2 RNA to produce C-to-U mutations. However, SARS-CoV-2 replication and viral progeny production in Caco-2 cells are not inhibited by the expression of these APOBECs. Instead, expression of wild-type APOBEC3 greatly promotes viral replication/propagation, suggesting that SARS-CoV-2 utilizes the APOBEC-mediated mutations for fitness and evolution. Unlike the random mutations, this study suggests the predictability of all possible viral genome mutations by these APOBECs based on the UC/AC motifs and the viral genomic RNA structure.

The Roles of APOBEC-mediated RNA Editing in SARS-CoV-2 Mutations, Replication and Fitness.. [PMID: 35441170 PMCID: PMC9016648 DOI: 10.21203/rs.3.rs-1524060/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

During COVID-19 pandemic, mutations of SARS-CoV-2 produce new strains that can be more infectious or evade vaccines. Viral RNA mutations can arise from misincorporation by RNA-polymerases and modification by host factors. Analysis of SARS-CoV-2 sequence from patients showed a strong bias toward C-to-U mutation, suggesting a potential mutational role by host APOBEC cytosine deaminases that possess broad anti-viral activity. We report the first experimental evidence demonstrating that APOBEC3A, APOBEC1, and APOBEC3G can edit on specific sites of SARS-CoV-2 RNA to produce C-to-U mutations. However, SARS-CoV-2 replication and viral progeny production in Caco-2 cells are not inhibited by the expression of these APOBECs. Instead, expression of wild-type APOBEC3 greatly promotes viral replication/propagation, suggesting that SARS-CoV-2 utilizes the APOBEC-mediated mutations for fitness and evolution. Unlike the random mutations, this study suggests the predictability of all possible viral genome mutations by these APOBECs based on the UC/AC motifs and the viral genomic RNA structure.

Efficient Editing of SARS-CoV-2 genomic RNA by Host APOBEC deaminases and Its Potential Impacts on the Viral Replication and Emergence of New Strains in COVID-19 Pandemic

Simultaneous Detection of Herpes Simplex Virus Type 1 Latent and Lytic Transcripts in Brain Tissue

Neurotrophic herpes simplex virus type 1 (HSV-1) establishes lifelong latent infection in humans. Accumulating studies indicate that HSV-1, a risk factor of neurodegenerative diseases, exacerbates the sporadic Alzheimer's disease (AD). The analysis of viral genetic materials via genomic sequencing and quantitative PCR (qPCR) is the current approach used for the detection of HSV-1; however, this approach is limited because of its difficulty in detecting both latent and lytic phases of the HSV-1 life cycle in infected hosts. RNAscope, a novel in situ RNA hybridization assay, enables visualized detection of multiple RNA targets on tissue sections. Here, we developed a fluorescent multiplex RNAscope assay in combination with immunofluorescence to detect neuronal HSV-1 transcripts in various types of mouse brain samples and human brain tissues. Specifically, the RNA probes were designed to separately recognize two transcripts in the same brain section: (1) the HSV-1 latency-associated transcript (LAT) and (2) the lytic-associated transcript, the tegument protein gene of the unique long region 37 (UL37). As a result, both LAT and UL37 signals were detectable in neurons in the hippocampus and trigeminal ganglia (TG). The quantifications of HSV-1 transcripts in the TG and CNS neurons are correlated with the viral loads during lytic and latent infection. Collectively, the development of combinational detection of neuronal HSV-1 transcripts in mouse brains can serve as a valuable tool to visualize HSV-1 infection phases in various types of samples from AD patients and facilitate our understanding of the infectious origin of neurodegeneration and dementia.

SARS-CoV-2 Nsp5 Demonstrates Two Distinct Mechanisms Targeting RIG-I and MAVS To Evade the Innate Immune Response

Newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic with astonishing mortality and morbidity. The high replication and transmission of SARS-CoV-2 are remarkably distinct from those of previous closely related coronaviruses, and the underlying molecular mechanisms remain unclear. The innate immune defense is a physical barrier that restricts viral replication. We report here that the SARS-CoV-2 Nsp5 main protease targets RIG-I and mitochondrial antiviral signaling (MAVS) protein via two distinct mechanisms for inhibition. Specifically, Nsp5 cleaves off the 10 most-N-terminal amino acids from RIG-I and deprives it of the ability to activate MAVS, whereas Nsp5 promotes the ubiquitination and proteosome-mediated degradation of MAVS. As such, Nsp5 potently inhibits interferon (IFN) induction by double-stranded RNA (dsRNA) in an enzyme-dependent manner. A synthetic small-molecule inhibitor blunts the Nsp5-mediated destruction of cellular RIG-I and MAVS and processing of SARS-CoV-2 nonstructural proteins, thus restoring the innate immune response and impeding SARS-CoV-2 replication. This work offers new insight into the immune evasion strategy of SARS-CoV-2 and provides a potential antiviral agent to treat CoV disease 2019 (COVID-19) patients. IMPORTANCE The ongoing COVID-19 pandemic is caused by SARS-CoV-2, which is rapidly evolving with better transmissibility. Understanding the molecular basis of the SARS-CoV-2 interaction with host cells is of paramount significance, and development of antiviral agents provides new avenues to prevent and treat COVID-19 diseases. This study describes a molecular characterization of innate immune evasion mediated by the SARS-CoV-2 Nsp5 main protease and subsequent development of a small-molecule inhibitor.

[A prospective study on the associations between dietary intakes of energy and macronutrients before menarche and age at menarche among girls]

Based on the data from China Health and Nutrition Survey (CHNS), 840 girls aged 6-15 years who had information about menarche and participated in dietary survey at least once within 1-5 years before onset of menarche between 1989 and 2015 were included in the study. The median age at baseline of the 840 participants was 10 (9, 11) years. The median age at menarche of the participants was 13 (12, 14) years. After adjusting for the age of birth, place of residence, body mass index Z-score, physical activity level and annual household income per capita, the average age of menarche was advanced by 0.036 (95%CI: -0.068, -0.004) years for every 10 g increase in daily fat intake before menarche. The average age at menarche was 0.008 (95%CI: -0.014, -0.001) years earlier for every 1% increase in the daily energy supply ratio of fat before menarche.

Dual roles of a novel oncolytic viral vector-based SARS-CoV-2 vaccine: preventing COVID-19 and treating tumor progression

The ongoing coronavirus disease 2019 (COVID-19) pandemic is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Cancer patients are usually immunocompromised and thus are particularly susceptible to SARS-CoV-2 infection resulting in COVID-19. Although many vaccines against COVID-19 are being preclinically or clinically tested or approved, none have yet been specifically developed for cancer patients or reported as having potential dual functions to prevent COVID-19 and treat cancer. Here, we confirmed that COVID-19 patients with cancer have low levels of antibodies against the spike (S) protein, a viral surface protein mediating the entry of SARS-CoV-2 into host cells, compared with COVID-19 patients without cancer. We developed an oncolytic herpes simplex virus-1 vector-based vaccine named oncolytic virus (OV)-spike. OV-spike induced abundant anti-S protein neutralization antibodies in both tumor-free and tumor-bearing mice, which inhibit infection of VSV-SARS-CoV-2 and wild-type (WT) live SARS-CoV-2 as well as the B.1.1.7 variant in vitro. In the tumor-bearing mice, OV-spike also inhibited tumor growth, leading to better survival in multiple preclinical tumor models than the untreated control. Furthermore, OV-spike induced anti-tumor immune response and SARS-CoV-2-specific T cell response without causing serious adverse events. Thus, OV-spike is a promising vaccine candidate for both preventing COVID-19 and enhancing the anti-tumor response.

One Sentence Summary

A herpes oncolytic viral vector-based vaccine is a promising vaccine with dual roles in preventing COVID-19 and treating tumor progression.

Species-Specific Deamidation of RIG-I Reveals Collaborative Action between Viral and Cellular Deamidases in HSV-1 Lytic Replication

Retinoic acid-inducible gene I (RIG-I) is a sensor that recognizes cytosolic double-stranded RNA derived from microbes to induce host immune response. Viruses, such as herpesviruses, deploy diverse mechanisms to derail RIG-I-dependent innate immune defense. In this study, we discovered that mouse RIG-I is intrinsically resistant to deamidation and evasion by herpes simplex virus 1 (HSV-1). Comparative studies involving human and mouse RIG-I indicate that N495 of human RIG-I dictates species-specific deamidation by HSV-1 UL37. Remarkably, deamidation of the other site, N549, hinges on that of N495, and it is catalyzed by cellular phosphoribosylpyrophosphate amidotransferase (PPAT). Specifically, deamidation of N495 enables RIG-I to interact with PPAT, leading to subsequent deamidation of N549. Collaboration between UL37 and PPAT is required for HSV-1 to evade RIG-I-mediated antiviral immune response. This work identifies an immune regulatory role of PPAT in innate host defense and establishes a sequential deamidation event catalyzed by distinct deamidases in immune evasion.IMPORTANCE Herpesviruses are ubiquitous pathogens in human and establish lifelong persistence despite host immunity. The ability to evade host immune response is pivotal for viral persistence and pathogenesis. In this study, we investigated the evasion, mediated by deamidation, of species-specific RIG-I by herpes simplex virus 1 (HSV-1). Our findings uncovered a collaborative and sequential action between viral deamidase UL37 and a cellular glutamine amidotransferase, phosphoribosylpyrophosphate amidotransferase (PPAT), to inactivate RIG-I and mute antiviral gene expression. PPAT catalyzes the rate-limiting step of the de novo purine synthesis pathway. This work describes a new function of cellular metabolic enzymes in host defense and viral immune evasion.

Targeting CTP Synthetase 1 to Restore Interferon Induction and Impede Nucleotide Synthesis in SARS-CoV-2 Infection

The newly emerged SARS-CoV-2 caused a global pandemic with astonishing mortality and morbidity. The mechanisms underpinning its highly infectious nature remain poorly understood. We report here that SARS-CoV-2 exploits cellular CTP synthetase 1 (CTPS1) to promote CTP synthesis and suppress interferon (IFN) induction. Screening a SARS-CoV-2 expression library identified ORF7b and ORF8 that suppressed IFN induction via inducing the deamidation of interferon regulatory factor 3 (IRF3). Deamidated IRF3 fails to bind the promoters of classic IRF3-responsible genes, thus muting IFN induction. Conversely, a shRNA-mediated screen focused on cellular glutamine amidotransferases corroborated that CTPS1 deamidates IRF3 to inhibit IFN induction. Functionally, ORF7b and ORF8 activate CTPS1 to promote de novo CTP synthesis while shutting down IFN induction. De novo synthesis of small-molecule inhibitors of CTPS1 enabled CTP depletion and IFN induction in SARS-CoV-2 infection, thus impeding SARS-CoV-2 replication. Our work uncovers a strategy that a viral pathogen couples immune evasion to metabolic activation to fuel viral replication. Inhibition of the cellular CTPS1 offers an attractive means for developing antiviral therapy that would be resistant to SARS-CoV-2 mutation.

Herpes Simplex Virus and Pattern Recognition Receptors: An Arms Race

Herpes simplex viruses (HSVs) are experts in establishing persistent infection in immune-competent humans, in part by successfully evading immune activation through diverse strategies. Upon HSV infection, host deploys pattern recognition receptors (PRRs) to recognize various HSV-associated molecular patterns and mount antiviral innate immune responses. In this review, we describe recent advances in understanding the contributions of cytosolic PRRs to detect HSV and the direct manipulations on these receptors by HSV-encoded viral proteins as countermeasures. The continuous update and summarization of these mechanisms will deepen our understanding on HSV-host interactions in innate immunity for the development of novel antiviral therapies, vaccines and oncolytic viruses.

DNA-PK deficiency potentiates cGAS-mediated antiviral innate immunity

Upon sensing cytosolic DNA, the enzyme cGAS induces innate immune responses that underpin anti-microbial defenses and certain autoimmune diseases. Missense mutations of PRKDC encoding the DNA-dependent protein kinase (DNA-PK) catalytic subunit (DNA-PKcs) are associated with autoimmune diseases, yet how DNA-PK deficiency leads to increased immune responses remains poorly understood. In this study, we report that DNA-PK phosphorylates cGAS and suppresses its enzymatic activity. DNA-PK deficiency reduces cGAS phosphorylation and promotes antiviral innate immune responses, thereby potently restricting viral replication. Moreover, cells isolated from DNA-PKcs-deficient mice or patients carrying PRKDC missense mutations exhibit an inflammatory gene expression signature. This study provides a rational explanation for the autoimmunity of patients with missense mutations of PRKDC, and suggests that cGAS-mediated immune signaling is a potential target for therapeutic interventions.

Viral pseudoenzymes in infection and immunity

Pseudoenzymes are proteins that are evolutionarily related to active enzymes, but lack relevant catalytic activity. As obligate intracellular pathogens, viruses complete their life cycle fully dependent on the cellular supplies of macromolecule and energy. Traditionally, studies of viral proteins sharing high homology with host counterparts reveal insightful mechanisms by which host signaling pathways are delicately regulated. Recent investigations into the action of cellular pseudoenzymes elucidate diverse molecular means how enzymes are differentially controlled under various physiological conditions, hinting to the potential that pathogens may exploit these regulatory modalities. To date, there have been three types of viral pseudoenzymes reported and our understanding concerning their mechanism of regulation is rudimentary at best. However, it is clear that viral pseudoenzymes are emerging with surprising functions in infection and immunity, and we are only at the beginning to understand this new group of enzyme regulators. In this review, we will summarize current knowledge in viral pseudoenzymes and provide a perspective for future research.

Influence of an InGaN superlattice pre-layer on the performance of semi-polar (11-22) green LEDs grown on silicon

It is well-known that it is crucial to insert either a single InGaN underlayer or an InGaN superlattice (SLS) structure (both with low InN content) as a pre-layer prior to the growth of InGaN/GaN multiple quantum wells (MQWs) served as an active region for a light-emitting diode (LED). So far, this growth scheme has achieved a great success in the growth of III-nitride LEDs on c-plane substrates, but has not yet been applied in the growth of any other orientated III-nitride LEDs. In this paper, we have applied this growth scheme in the growth of semi-polar (11–22) green LEDs, and have investigated the impact of the SLS pre-layer on the optical performance of semi-polar (11–22) green LEDs grown on patterned (113) silicon substrates. Our results demonstrate that the semi-polar LEDs with the SLS pre-layer exhibit an improvement in both internal quantum efficiency and light output, which is similar to their c-plane counterparts. However, the performance improvement is not so significant as in the c-plane case. This is because the SLS pre-layer also introduces extra misfit dislocations for the semi-polar, but not the c-plane case, which act as non-radiative recombination centres.

Attitude and knowledge for menopause management among health professionals in mainland China

OBJECTIVE

This study aims to understand the attitude of health-care professionals (HPs) in mainland China toward menopause management (MM) as well as the knowledge they have received regarding MM during training.

METHODS

An anonymous survey recruited 3709 medical workers nationwide (including physicians, orthopedists, obstetricians and gynecologists, and general practitioners) through online surveys and on-site interviews at professional meetings.

RESULTS

Of the 3709 questionnaires completed, 3426 questionnaires met the inclusion criteria. Of the participants, 1532 HPs had not received menopause management training (MMT) in nearly 1 year. Among the residents and physician assistants, 103 reported they were not familiar with MM. Satisfyingly, 98.3% of HPs considered it very important or essential to accept MM. Although most interviewees replied some correct menopausal knowledge, nearly half of them could not correctly identify the contraindications for menopause hormone therapy (MHT). Additionally, 73.1% of HPs would advise patients with premature ovarian insufficiency to receive hormone replacement therapy at least until the average age of menopause.

CONCLUSION

This survey indicated that HPs have some knowledge regarding MM, but a gap remains to master the basic theory of MHT. In order to manage the growing menopausal population in China, creating more in-depth educational MMT programs for HPs is necessary.

Herpesvirus-bacteria synergistic interaction in periodontitis

The etiopathogenesis of severe periodontitis includes herpesvirus-bacteria coinfection. This article evaluates the pathogenicity of herpesviruses (cytomegalovirus and Epstein-Barr virus) and periodontopathic bacteria (Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis) and coinfection of these infectious agents in the initiation and progression of periodontitis. Cytomegalovirus and A. actinomycetemcomitans/P. gingivalis exercise synergistic pathogenicity in the development of localized ("aggressive") juvenile periodontitis. Cytomegalovirus and Epstein-Barr virus are associated with P. gingivalis in adult types of periodontitis. Periodontal herpesviruses that enter the general circulation may also contribute to disease development in various organ systems. A 2-way interaction is likely to occur between periodontal herpesviruses and periodontopathic bacteria, with herpesviruses promoting bacterial upgrowth, and bacterial factors reactivating latent herpesviruses. Bacterial-induced gingivitis may facilitate herpesvirus colonization of the periodontium, and herpesvirus infections may impede the antibacterial host defense and alter periodontal cells to predispose for bacterial adherence and invasion. Herpesvirus-bacteria synergistic interactions, are likely to comprise an important pathogenic determinant of aggressive periodontitis. However, mechanistic investigations into the molecular and cellular interaction between periodontal herpesviruses and bacteria are still scarce. Herpesvirus-bacteria coinfection studies may yield significant new discoveries of pathogenic determinants, and drug and vaccine targets to minimize or prevent periodontitis and periodontitis-related systemic diseases.

Oncogenic human herpesvirus hijacks proline metabolism for tumorigenesis

Three-dimensional (3D) cell culture is well documented to regain intrinsic metabolic properties and to better mimic the in vivo situation than two-dimensional (2D) cell culture. Particularly, proline metabolism is critical for tumorigenesis since pyrroline-5-carboxylate (P5C) reductase (PYCR/P5CR) is highly expressed in various tumors and its enzymatic activity is essential for in vitro 3D tumor cell growth and in vivo tumorigenesis. PYCR converts the P5C intermediate to proline as a biosynthesis pathway, whereas proline dehydrogenase (PRODH) breaks down proline to P5C as a degradation pathway. Intriguingly, expressions of proline biosynthesis PYCR gene and proline degradation PRODH gene are up-regulated directly by c-Myc oncoprotein and p53 tumor suppressor, respectively, suggesting that the proline-P5C metabolic axis is a key checkpoint for tumor cell growth. Here, we report a metabolic reprogramming of 3D tumor cell growth by oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV), an etiological agent of Kaposi's sarcoma and primary effusion lymphoma. Metabolomic analyses revealed that KSHV infection increased nonessential amino acid metabolites, specifically proline, in 3D culture, not in 2D culture. Strikingly, the KSHV K1 oncoprotein interacted with and activated PYCR enzyme, increasing intracellular proline concentration. Consequently, the K1-PYCR interaction promoted tumor cell growth in 3D spheroid culture and tumorigenesis in nude mice. In contrast, depletion of PYCR expression markedly abrogated K1-induced tumor cell growth in 3D culture, not in 2D culture. This study demonstrates that an increase of proline biosynthesis induced by K1-PYCR interaction is critical for KSHV-mediated transformation in in vitro 3D culture condition and in vivo tumorigenesis.

[The association of pre-pregnancy body mass and weight gain during pregnancy with macrosomia: a cohort study]

Objective: To examine the association of pre-pregnancy body mass and weight gain during pregnancy with macrosomia. Methods: From January 2015 to December 2015, a total of 20 477 pregnant women were recruited by probabilistic proportional scale sampling with simple randomization in Sichuan, Yunnan and Guizhou Provinces. Basic information of pregnant women, weight gain during pregnancy and weight of newborn were collected. A multiple logistic regression model was used to assess the association between the pre-pregnancy body mass and gestational weight gain indicators with macrosomia. Results: 20 321 mother-infant were included in the final analysis. 20 321 pregnant women were (30.09±4.10) years old and delivered at (39.20±1.29) weeks, among which 12 341 (60.73%) cases were cesarean delivery. The birth weight of 20 321 infants were (3 292.26±431.67) grams, and 970 (4.77%) were macrosomia. The multiple logistic regression model showed that after adjusting for the age of women, compared to the normal weight group in the pre-pregnancy, the overweight and obesity group elevated the risk of macrosomia, with OR (95%CI) about 1.99 (95%CI: 1.69-2.35) and 4.05 (95%CI: 3.05-5.39), respectively. After adjusting for the age, the pre-pregnancy BMI, delivery weeks, delivery mode and infant's gender, compared to the weight-gain appropriate group, higher weight gain rate in the mid-pregnancy and excessive total gestational weight gain elevated the risk of macrosomia, with OR (95%CI) about 1.99 (95%CI: 1.66-2.39) and 1.80 (95%CI: 1.55-2.08), respectively. Conclusion: The overweight before pregnancy, obesity before pregnancy, the rate of weight gain in the second trimester and the high total weight gain during pregnancy could increase the risk of macrosomia.

Post-translational Control of Innate Immune Signaling Pathways by Herpesviruses

Herpesviruses constitute a large family of disease-causing DNA viruses. Each herpesvirus strain is capable of infecting particular organisms with a specific cell tropism. Upon infection, pattern recognition receptors (PRRs) recognize conserved viral features to trigger signaling cascades that culminate in the production of interferons and pro-inflammatory cytokines. To invoke a proper immune response while avoiding collateral tissue damage, signaling proteins involved in these cascades are tightly regulated by post-translational modifications (PTMs). Herpesviruses have developed strategies to subvert innate immune signaling pathways in order to ensure efficient viral replication and achieve persistent infection. The ability of these viruses to control the proteins involved in these signaling cascades post-translationally, either directly via virus-encoded enzymes or indirectly through the deregulation of cellular enzymes, has been widely reported. This ability provides herpesviruses with a powerful tool to shut off or restrict host antiviral and inflammatory responses. In this review, we highlight recent findings on the herpesvirus-mediated post-translational control along PRR-mediated signaling pathways.

Black carp IRF5 interacts with TBK1 to trigger cell death following viral infection

Interferon regulated factor 5 (IRF5) is a key regulator of inflammatory responses in human and mammals; however, its role in teleost remains largely unknown. In this study, IRF5 homologue of black carp (Mylopharyngodon piceus) has been cloned and characterized, which possesses conservation in structure and sequence to its mammalian counterparts. Black carp IRF5 (bcIRF5) was characterized as a predominantly cytosolic protein by immunofluorescent staining and showed little IFN promoter-inducing ability in reporter assay. The direct association between bcIRF5 and black carp TBK1 (bcTBK1) were identified through co-immunoprecipitation assay, and co-expressed bcIRF5 in EPC cells suppressed bcTBK1-mediated IFN promoter transcription in reporter assay. Surprisingly, the titer of grass carp reovirus (GCRV) in the media of EPC cells co-expressing bcIRF5 and bcTBK1 was obviously lower than that of EPC cells expressing bcTBK1 alone. It was interesting that expression of bcIRF5 and/or bcTBK1 in EPC cells showed little effect on cell growth; however, the survival ratio of EPC cells co-expressing bcTBK1 and bcIRF5 post GCRV infection was much lower than that of EPC cells expressing bcIRF5 or bcTBK1 alone. These results indicate that bcIRF5 negatively regulates bcTBK1-mediated IFN signaling in healthy cells; however, it correlates with bcTBK1 and triggers cell death to inhibit the virus replication during the innate immune activation.

Antiviral activity of a purine synthesis enzyme reveals a key role of deamidation in regulating protein nuclear import

Protein nuclear translocation is highly regulated and crucial for diverse biological processes. However, our understanding concerning protein nuclear import is incomplete. Here we report that a cellular purine synthesis enzyme inhibits protein nuclear import via deamidation. Employing human Kaposi's sarcoma-associated herpesvirus (KSHV) to probe the role of protein deamidation, we identified a purine synthesis enzyme, phosphoribosylformylglycinamidine synthetase (PFAS) that inhibits KSHV transcriptional activation. PFAS deamidates the replication transactivator (RTA), a transcription factor crucial for KSHV lytic replication. Mechanistically, deamidation of two asparagines flanking a positively charged nuclear localization signal impaired the binding of RTA to an importin β subunit, thus diminishing RTA nuclear localization and transcriptional activation. Finally, RTA proteins of all gamma herpesviruses appear to be regulated by PFAS-mediated deamidation. These findings uncover an unexpected function of a metabolic enzyme in restricting viral replication and a key role of deamidation in regulating protein nuclear import.

Viperin catalyzes methionine oxidation to promote protein expression and function of helicases

Helicases play pivotal roles in fundamental biological processes, and posttranslational modifications regulate the localization, function, and stability of helicases. Here, we report that methionine oxidation of representative helicases, including DNA and RNA helicases of viral (ORF44 of KSHV) and cellular (MCM7 and RIG-I) origin, promotes their expression and functions. Cellular viperin, a major antiviral interferon-stimulated gene whose functions beyond host defense remain largely unknown, catalyzes the methionine oxidation of these helicases. Moreover, biochemical studies entailing loss-of-function mutations of helicases and a pharmacological inhibitor interfering with lipid metabolism and, hence, decreasing viperin activity indicate that methionine oxidation potently increases the stability and enzyme activity of these helicases that are critical for DNA replication and immune activation. Our work uncovers a pivotal role of viperin in catalyzing the methionine oxidation of helicases that are implicated in diverse fundamental biological processes.

Modulation of Innate Immune Signaling Pathways by Herpesviruses

Herpesviruses can be detected by pattern recognition receptors (PRRs), which then activate downstream adaptors, kinases and transcription factors (TFs) to induce the expression of interferons (IFNs) and inflammatory cytokines. IFNs further activate the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, inducing the expression of interferon-stimulated genes (ISGs). These signaling events constitute host innate immunity to defeat herpesvirus infection and replication. A hallmark of all herpesviruses is their ability to establish persistent infection in the presence of active immune response. To achieve this, herpesviruses have evolved multiple strategies to suppress or exploit host innate immune signaling pathways to facilitate their infection. This review summarizes the key host innate immune components and their regulation by herpesviruses during infection. Also we highlight unanswered questions and research gaps for future perspectives.

Predicting cyanobacteria bloom occurrence in lakes and reservoirs before blooms occur

With increased global warming, cyanobacteria are blooming more frequently in lakes and reservoirs, severely damaging the health and stability of aquatic ecosystems and threatening drinking water safety and human health. There is an urgent demand for the effective prediction and prevention of cyanobacterial blooms. However, it is difficult to effectively reduce the risks and loss caused by cyanobacterial blooms because most methods are unable to successfully predict cyanobacteria blooms. Therefore, in this study, we proposed a new cyanobacterial bloom occurrence prediction method to analyze the probability and driving factors of the blooms for effective prevention and control. Dominant cyanobacterial species with bloom capabilities were initially determined using a dominant species identification model, and the principal driving factors of the dominant species were then analyzed using canonical correspondence analysis (CCA). Cyanobacterial bloom probability was calculated using a newly-developed model, after which, the probable mutation points were identified and thresholds for the principal driving factors of cyanobacterial blooms were predicted. A total of 141 phytoplankton data sets from 90 stations were collected from six large-scale hydrology, water-quality ecology, integrated field surveys in Jinan City, China in 2014-2015 and used for model application and verification. The results showed that there were six dominant cyanobacterial species in the study area, and that the principal driving factors were water temperature, pH, total phosphorus, ammonia nitrogen, chemical oxygen demand, and dissolved oxygen. The cyanobacterial blooms corresponded to a threshold water temperature range, pH, total phosphorus (TP), ammonium nitrogen level, chemical oxygen demand, and dissolved oxygen levels of 19.5-32.5 °C, 7.0-9.38, 0.13-0.22 mg L^-1, 0.38-0.63 mg L^-1, 10.5-17.5 mg L^-1, and 4.97-8.28 mg L^-1, respectively. Comparison with research results from other global regions further supported the use of these thresholds, indicating that this method could be used in habitats beyond China. We found that the probability of cyanobacterial bloom was 0.75, a critical point for prevention and control. When this critical point was exceeded, cyanobacteria could proliferate rapidly, increasing the risk of cyanobacterial blooms. Changes in driving factors need to be rapidly controlled, based on these thresholds, to prevent cyanobacterial blooms. Temporal and spatial scales were critical factors potentially affecting the selection of driving factors. This method is versatile and can help determine the risk of cyanobacterial blooms and the thresholds of the principal driving factors. It can effectively predict and help prevent cyanobacterial blooms to reduce the global probability of occurrence, protect the health and stability of water ecosystems, ensure drinking water safety, and protect human health.

Quantitative assessment of the effects of human activities on phytoplankton communities in lakes and reservoirs

Global algal blooms have been severely threatening safety of drinking water and development of socio-economy. Effective prevention and accurate control of algal blooms require a quantitative assessment of the influence of human activities and identification of priority areas. However, previous studies on the quantitative assessment of the effects of human activities on algal communities are lacking, severely hindering the effective and precise control of algal blooms. This paper proposes a quantitative assessment model to evaluate the impact intensity of human activities on phytoplankton. Applications showed that the proliferation of phytoplankton were more limited by nutrients such as total phosphorus and ammonia where waters are less influenced by human activities, yet were less limited by these nutrients where there are highly intensive human activities. The density of phytoplankton in waters increased with an increase in human activity intensity, particularly in concentrated agricultural areas, which are priority areas for the prevention and control of algal blooms. The methodologies can clearly identify key areas for algal bloom prevention and control and can provide scientific evidence for water and nutrient management throughout the world, reducing the risk of algal blooms and ensuring aquatic ecosystem health and potable water safety.

STAT1a and STAT1b of black carp play important roles in the innate immune defense against GCRV

Signal transducer and activator of transcription 1 (STAT1) plays an important role in the Janus kinase (JAK)-STAT signaling of human and mammals; however, the mechanism of STAT1 in innate immune activation of teleost fishes remains largely unknown. In this study, two STAT1 homologues (bcSTAT1a and bcSTAT1b) of black carp (Mylopharyngodon piceus) have been cloned and characterized. Both bcSTAT1a and bcSTAT1b transcription in host cells was obviously increased in response to the stimulation of poly (I:C), lipopolysaccharide (LPS), grass carp reovirus (GCRV) and interferon (IFN); however, the increase rate of bcSTAT1b transcription post stimulation was obviously higher than that of bcSTAT1a. bcSTAT1a and bcSTAT1b were distributed in both cytoplasm and nucleus in the immunofluorescence staining assay. Self-association of bcSTAT1a and bcSTAT1b, and the interaction between bcSTAT1a and bcSTAT1b have been detected through co-immunoprecipitation (co-IP) assay; and the data of native polyacrylamide gel electrophoresis (PAGE) implied that bcSTAT1a and bcSTAT1b might form homodimer and heterodimer in vivo like their mammalian counterparts. Both bcSTAT1a and bcSTAT1b presented IFN-inducing ability in report assay, and both bcSTAT1a and bcSTAT1b showed antiviral activities against GCRV in EPC cells. Our data support the conclusion that both bcSTAT1a and bcSTAT1b play important roles in host antiviral innate immune activation initiated by GCRV.

FoxO1 Suppresses Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication and Controls Viral Latency

Kaposi's sarcoma-associated herpesvirus (KSHV) has latent and lytic replication phases, both of which contribute to the development of KSHV-induced malignancies. Among the numerous factors identified to regulate the KSHV life cycle, oxidative stress, caused by imbalanced clearing and production of reactive oxygen species (ROS), has been shown to robustly disrupt KSHV latency and induce viral lytic replication. In this study, we identified an important role of the antioxidant defense factor forkhead box protein O1 (FoxO1) in the KSHV life cycle. Either chemical inhibition of the FoxO1 function or knockdown of FoxO1 expression led to an increase in the intracellular ROS level that was subsequently sufficient to disrupt KSHV latency and induce viral lytic reactivation. On the other hand, treatment with N-acetyl-l-cysteine (NAC), an oxygen free radical scavenger, led to a reduction in the FoxO1 inhibition-induced ROS level and, ultimately, the attenuation of KSHV lytic reactivation. These findings reveal that FoxO1 plays a critical role in keeping KSHV latency in check by maintaining the intracellular redox balance.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with several cancers, including Kaposi's sarcoma (KS). Both the KSHV latent and lytic replication phases are important for the development of KS. Identification of factors regulating the KSHV latent phase-to-lytic phase switch can provide insights into the pathogenesis of KSHV-induced malignancies. In this study, we show that the antioxidant defense factor forkhead box protein O1 (FoxO1) maintains KSHV latency by suppressing viral lytic replication. Inhibition of FoxO1 disrupts KSHV latency and induces viral lytic replication by increasing the intracellular ROS level. Significantly, treatment with an oxygen free radical scavenger, N-acetyl-l-cysteine (NAC), attenuated the FoxO1 inhibition-induced intracellular ROS level and KSHV lytic replication. Our works reveal a critical role of FoxO1 in suppressing KSHV lytic replication, which could be targeted for antiviral therapy.

Development of a three-wave far-infrared laser interferometry and polarimetry diagnostic system for the C-2W field-reversed configuration plasmas

Great advancements in modern field-reversed configuration (FRC) experiments motivated the development of a 14-chord three-wave far infrared (FIR) laser interferometry and polarimetry diagnostic system, which can provide simultaneous high temporal resolution measurements of density and Faraday rotation profiles with high accuracy. The unique challenges facing FIR diagnostics in high beta FRC plasmas are the extremely small (<0.5°) Faraday rotation angles, and severe laser beam refraction effects due to high density gradient and choice of long wavelength. The diagnostic system design and development are described with methods to overcome the challenges, and initial experimental data are also presented.

Interplay between Cellular Metabolism and Cytokine Responses during Viral Infection

Metabolism and immune responses are two fundamental biological processes that serve to protect hosts from viral infection. As obligate intracellular pathogens, viruses have evolved diverse strategies to activate metabolism, while inactivating immune responses to achieve maximal reproduction or persistence within their hosts. The two-way virus-host interaction with metabolism and immune responses choreograph cytokine production via reprogramming metabolism of infected cells/hosts. In return, cytokines can affect the metabolism of virus-infected and bystander cells to impede viral replication processes. This review aims to summarize our current understanding of the cross-talk between metabolic reprogramming and cytokine responses, and to highlight future potential research topics. Although the focus is placed on viral pathogens, relevant findings from other microbes are integrated to provide an overall picture, particularly when corresponding information on viral infection is lacking.