Genome-Wide Association Analysis of Effective Tillers in Rice under Different Nitrogen Gradients.

Nitrogen is a crucial element that impacts rice yields, and effective tillering is a significant agronomic characteristic that can influence rice yields. The way that reduced nitrogen affects effective tillering is a complex quantitative trait that is controlled by multiple genes, and its genetic basis requires further exploration. In this study, 469 germplasm varieties were used for a genome-wide association analysis aiming to detect quantitative trait loci (QTL) associated with effective tillering at low (60 kg/hm2) and high (180 kg/hm2) nitrogen levels. QTLs detected over multiple years or under different treatments were scrutinized in this study, and candidate genes were identified through haplotype analysis and spatio-temporal expression patterns. A total of seven genes (NAL1, OsCKX9, Os01g0690800, Os02g0550300, Os02g0550700, Os04g0615700, and Os04g06163000) were pinpointed in these QTL regions, and were considered the most likely candidate genes. These results provide favorable information for the use of auxiliary marker selection in controlling effective tillering in rice for improved yields.

Development and validation of a nomogram for predicting overall survival in patients with sinonasal mucosal melanoma.

BACKGROUND: Sinonasal mucosal melanoma (SNMM) is a relatively rare malignant tumour with a poor prognosis. This study was designed to identify prognostic factors and establish a nomogram model to predict the overall survival (OS) of patients with SNMM. METHODS: A total of 459 patients with SNMM were selected from the Surveillance, Epidemiology, and End Results (SEER) database as the training cohort. Univariate and multivariate Cox regression analyses were used to screen for independent factors associated with patient prognosis and develop the nomogram model. In addition, external validation was performed to evaluate the effectiveness of the nomogram with a cohort of 34 patients with SNMM from Peking Union Medical College Hospital. RESULTS: The median OS in the cohort from the SEER database was 28 months. The 1-year, 3-year and 5-year OS rates were 69.8%, 40.4%, and 30.0%, respectively. Multivariate Cox regression analysis indicated that age, T stage, N stage, surgery and radiotherapy were independent variables associated with OS. The areas under the receiver operating characteristic curves (AUCs) of the nomograms for predicting 1-, 3- and 5-year OS were 0.78, 0.71 and 0.71, respectively, in the training cohort. In the validation cohort, the area under the curve (AUC) of the nomogram for predicting 1-, 3- and 5-year OS were 0.90, 0.75 and 0.78, respectively. Patients were classified into low- and high-risk groups based on the total score of the nomogram. Patients in the low-risk group had a significantly better survival prognosis than patients in the high-risk group in both the training cohort (P < 0.0001) and the validation cohort (P = 0.0016). CONCLUSION: We established and validated a novel nomogram model to predict the OS of SNMM patients stratified by age, T stage, N stage, surgery and radiotherapy. This predictive tool is of potential importance in the realms of patient counselling and clinical decision-making.

Infratemporal Fossa Metastasis of Non-Small-Cell Lung Adenocarcinoma: A Case Report and Literature Review.

Neoplasms in the infratemporal fossa (ITF) are rare and insidious lesions that cause various symptoms due to involvement of the temporomandibular joint (TMJ), paranasal sinuses, and orbit. Here, we report a case of metastatic non-small cell lung adenocarcinoma in the ITF. The patient presented with facial pain and limited mouth opening, which did not respond to treatment for TMJ disorder, and a neoplasm was discovered in the ITF through medical imaging. With an open biopsy, the diagnosis was finalized. This report suggested that the physician should consider lesions in the ITF when facial pain and limited mouth opening failed local treatment, and distant metastasis of malignant tumor should be alerted. We also reviewed the literature regarding metastatic cancer to the ITF.

Burden of stroke in China and the different SDI regions over the world.

Background: Stroke is a significant global health issue, ranking as the second leading cause of death and the third leading cause of death and disability combined. This study aimed to examine the changes and differences in stroke burden from 1990 to 2019 in China and various global socio-demographic index (SDI) regions. Methods: Data were obtained from the Global Burden of Diseases Study 2019, which included the incidence, prevalence, mortality, disability-adjusted life years (DALY), years of life with disability (YLD), and years of life lost (YLL) of stroke. The change trend of stroke burden was assessed based on age-standardised rates per 100 000 person-years and estimated annual percentage changes. The average annual rate of change in stroke burden was analysed using the average annual percentage change from 1990 to 2019. Pearson correlation analysis was used to explore the strength and direction of the correlation between stroke burden and SDI. Results: Regions with high SDI showed the largest decline in age-standardised incidence, death, DALY, YLD, and YLL rates of stroke from 1990 to 2019. China experienced the largest increase in age-standardised prevalence and YLD rates of stroke from 1990 to 2019. There were significant differences in the average annual percent change in stroke burden among the majority of SDI regions. The burden for stroke at the national level was inversely correlated with SDI, despite some exceptions (Incidence: R = -0.417, P < 0.001; prevalence: R = -0.297, P < 0.001; mortality: R = -0.510, P < 0.001; DALY: R = -0.550, P < 0.001; YLD: R = -0.125, P = 0.075; YLL: R = -0.569, P < 0.001). Conclusions: There were significant differences in the stroke burden across different regions with varying SDI levels from 1990 to 2019. The age-standardised prevalence rate and attributable disability burden of stroke remain substantial in different SDI regions, making it a major contributor to the overall disease burden. The severe burden of stroke highlights the importance of primary and secondary stroke-prevention strategies. Therefore, future strategies to prevent and reduce the burden of stroke should be formulated and implemented according to the SDI of each country.

Adverse Events for Monoclonal Antibodies in Patients with Allergic Rhinitis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

(1) Background: Allergic rhinitis (AR) is a common disease in otolaryngology and novel biological therapies are required for clinical needs. To assess the tolerability of monoclonal antibodies, justifying their clinical applications, we presented a comprehensive safety profile of biologics in AR; (2) Methods: A systematic literature search was conducted following PRISMA guidelines for randomized clinical trials comparing monoclonal antibodies and placebo in AR. PubMed, Web of Science, Medline, and Cochrane were searched up until 9 January 2023. Among 3590 records in total, 12 studies with more than 2600 patients were included. Quality was assessed for all studies using Cochrane risk-of-bias tool for randomized trials, and subgrouped meta-analysis was performed; (3) Results: We accomplished an up-to-date literature overview and analysis on adverse events of monoclonal antibodies in AR. Total, common, severe, discontinuation-causing, and serious adverse events failed to reach statistical significance. Country was an essential factor for heterogeneity, and urticaria was the adverse event at highest risk (RR 2.81, 95% CI 0.79-9.95); (4) Conclusions: Monoclonal antibodies are considered well tolerated and relatively safe in patients with AR. The regions of patients and hypersensitive adverse reactions such as urticaria require a special caution in biological treatments in AR.

Sinonasal NUT carcinoma: A retrospective case series from a single institution.

Purpose: Nuclear protein in testis (NUT) carcinoma is a rare, aggressive tumor defined by the presence of NUT gene rearrangement. The aim of this study was to describe the clinical, radiologic, and biological features of sinonasal NUT carcinoma. Methods: We retrospectively investigated NUT expression with clinicopathologic features in 145 cases with sinonasal malignancies diagnosed from January 2017 to December 2021 and reviewed the reported cases. Results: Three (3/145, 2.07%) cases showed strong nuclear expression for NUT immunohistochemical, including one male and two females with ages from 37 to 57 years (mean, 45.33 years). All three cases involved the nasal cavity and sinuses; one of them involved the orbit and intracranial area. Histologically, all subjects showed poorly differentiated, small round cell morphology with distinct nuclei. All patients received surgery and chemoradiotherapy. One patient died of the disease 13 months after diagnosis, and two survived 12 and 15 months, respectively, without evidence of tumor recurrence. 51 cases of sinonasal NUT carcinoma (mean age 40.96 years) have been described to date. Among them, 28 are male, and 23 are female. Most cases expressed p63, AE1/AE3, as well as p40. Conclusion: NUT carcinoma is a rare and aggressive disease with a poor prognosis. It is crucial to perform NUT rearrangement-related tests for differential diagnosis of poorly differentiated/undifferentiated tumors in the nasal cavity and sinuses.

A study of primary health care service efficiency and its spatial correlation in China.

BACKGROUND: China's primary health care system has undergone major changes since the new round of medical reform in 2009, but the current status of primary health care institution service efficiency is still unsatisfactory. The purpose of this study is to compare and evaluate the China's primary health care institution service efficiency and provide a reference for improving the efficiency and promoting the development of primary health care institution. METHODS: Based on panel data of 31 provinces (municipalities directly under the central government and autonomous regions) in mainland China from 2011 to 2020, using the super efficiency slack-based measure-data envelopment analysis model, to analyze the data from a static perspective, and the changes in the efficiency of primary health care services were analyzed from a dynamic perspective by using the Malmquist index method. Spatial autocorrelation analysis method was used to verify the spatial correlation of primary health care service efficiency among various regions. RESULTS: The number of Primary health care institutions increased from 918,000 in 2011 to 970,000 in 2020. The average primary health care institution service efficiency in the northeastern region including Jilin (0.324), Heilongjiang (0.460), Liaoning (0.453) and northern regions such as Shaanxi (0.344) and Neimenggu (0.403) was at a low level, while the eastern coastal regions such as Guangdong (1.116), Zhejiang (1.211), Shanghai (1.402) have higher average service efficiency levels. The global Moran's I showed the existence of spatial autocorrelation, and the local Moran's I index suggested that the problem of uneven regional development was prominent, showing a contiguous regional distribution pattern. Among them, H-H (high-efficiency regions) were mainly concentrated in Jiangsu, Anhui and Shanghai, and L-L regions (low-efficiency regions) were mostly in northern and northeastern China. CONCLUSION: The service efficiency of primary health care institution in China showed a rising trend in general, but the overall average efficiency was still at a low level, and there were significant geographical differences, which showed a spatial distribution of "high in the east and low in the west, high in the south and low in the north". The northwestern region, after receiving relevant support, has seen a rapid development of primary health care, and its efficiency was steadily improving and gradually reaching a high level. The average primary health care institution service efficiency in the northeastern region including the northern region of China was at a low level, while the average efficiency in the eastern coastal region and some economically developed regions was high, which also verifies the dependence and high symbiosis of primary health care institution service efficiency on regional economy.

Development of an Inactivated Avian Influenza Virus Vaccine against Circulating H9N2 in Chickens and Ducks.

Avian influenza virus (AIV) subtype H9N2 is the most widespread AIV in poultry worldwide, causing great economic losses in the global poultry industry. Chickens and ducks are the major hosts and play essential roles in the transmission and evolution of H9N2 AIV. Vaccines are considered an effective strategy for fighting H9N2 infection. However, due to the differences in immune responses to infection, vaccines against H9N2 AIV suitable for use in both chickens and ducks have not been well studied. This study developed an inactivated H9N2 vaccine based on a duck-origin H9N2 AIV and assessed its effectiveness in the laboratory. The results showed that the inactivated H9N2 vaccine elicited significant haemagglutination inhibition (HI) antibodies in both chickens and ducks. Virus challenge experiments revealed that immunization with this vaccine significantly blocked virus shedding after infection by both homogenous and heterologous H9N2 viruses. The vaccine was efficacious in chicken and duck flocks under normal field conditions. We also found that egg-yolk antibodies were produced by laying birds immunized with the inactivated vaccine, and high levels of maternal antibodies were detected in the serum of the offspring. Taken together, our study showed that this inactivated H9N2 vaccine could be extremely favourable for the prevention of H9N2 in both chickens and ducks.

Influencing Factors of International Students' Anxiety Under Online Learning During the COVID-19 Pandemic: A Cross-Sectional Study of 1,090 Chinese International Students.

Objective: We conducted the following cross-sectional study to comprehensively assess the anxiety among Chinese international students who studied online during the COVID-19 pandemic and its influencing factors. Methods: Questionnaires were distributed through "Sojump," and a total of 1,090 valid questionnaires were collected. The questionnaire was divided into two parts: general situation and anxiety assessment of students. The former used a self-made questionnaire, and the international general GAD-7 scale was used to measure anxiety. Chi-square test was used to analyze the differences between groups, and logistic regression analysis was performed for the factors with differences. Results: Anxiety was found in 707 (64.9%) of 1,090 international students. Chi-square test and multivariate Logistic regression analysis showed that the incidence of anxiety was higher in the group under 22 years of age than in the group over 22 years of age (68% vs. 61%, p = 0.015; OR = 1.186, 95% CI 1.045-1.347, p = 0.008); International students living in big cities had a higher incidence of anxiety than those living in rural areas (67% vs. 60%, p = 0.022; OR = 1.419, 95%CI 1.038-1.859, p = 0.011); international students who socialized 3 times or less monthly had a higher incidence of anxiety than those who socialized more than 3 times per month (68% vs. 58%, p = 0.003; OR = 1.52, 95%CI 1.160-1.992, p = 0.002); international students who expected purely online teaching had a higher incidence of anxiety than those who expected purely offline teaching or dual-track teaching (72% vs. 64%, p = 0.037; OR = 1.525, 95%CI 1.069-2.177, p = 0.02); international students with a subjective score of online learning experience of 6 or less had a higher incidence of anxiety than those with subjective scores of more than 6 (70% vs. 60%, p = 0.001, OR = 1.25, 95%CI 1.099-1.422, p = 0.001). However, gender, emotional status, BMI, major of study, vaccination status, and degree type had no significant difference in the incidence of anxiety among international students who studied online during the COVID-19 pandemic. Conclusion: During COVID-19, international students who were younger, came from big cities, had low social frequency, expected purely online teaching, and had poor experience of online classes were risk factors for anxiety during online classes.

Heat shock protein 70 (HSP70) plays important role in tembusu virus infection.

Tembusu virus (TMUV) is an avian-origined flavivirus that is prevalent in ducks and geese. TMUV causes reduced egg production and neurological problems, resulting in profound economic losses to the waterfowl industry. In the viral life cycle, cellular factors are required for viral entry, replication, assembly, release and so on. Heat shock protein 70 (HSP70) is reported to be involved in the replication of multiple viruses. In this study, we explored the roles of HSP70 in the TMUV life cycle. The results showed that TMUV infection induced HSP70 expression starting 12 h post-infection. An HSP70 inhibitor reduced TMUV viral RNA production and the number of virus particles, whereas an HSP70 activator enhanced the amount of viral RNA and virions that released from the cells. Further analysis revealed that HSP70 played important roles in the postentry stages of the TMUV life cycle, including viral replication, assembly and release. We also found that inhibition of HSP70 expression significantly reduced TMUV-induced apoptosis. Additionally, incubation of TMUV particles with an anti-HSP70 antibody significantly reduced viral infectivity, suggesting an association between HSP70 and TMUV particles. These results implicate HSP70 in the life cycle of TMUV, and therefore, targeting HSP70 may be a strategy for developing an anti-TMUV therapy.

The E3 Ubiquitin Ligase TRIM25 Inhibits Tembusu Virus Replication in vitro.

Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused significant economic losses to the duck industry in China since 2010 due to egg production losses and neurological dysfunction. DTMUV is a public health concern because the infection spreads rapidly among birds. Retinoic acid-inducible gene-I (RIG-I)serves as an innate immune sensor and plays a key role in host antiviral defenses. Tripartite motif-containing protein 25 (TRIM25), an E3 ubiquitin ligase, is pivotal for RIG-I ubiquitination and activation. In addition, TRIM25 acts as an interferon-stimulated gene and mediates the antiviral activity. However, the effect of duck TRIM25 on DTMUV has not been assessed. Herein, we reportthe antiviral function of TRIM25 against DTMUV. First, we constructed the pcDNA3.1-c-myc-duTRIM25 plasmid. TRIM25 has a 2052 bp open reading frame that encodes a predicted 684 amino acid protein consisting of a RING finger domain, a B-box domain, a coiled-coil domain, and a PRY/SPRY domain. The protein sequence identity with chicken, mouse, and human TRIM25 is 69.7, 47.8, and 48.3%, respectively. TRIM25 was upregulated in BHK-21 cells, duck embryo fibroblasts, and 293T cellsupon DTMUV infection. The expression of viral RNA and proteins was significantly lower in cells over expressing TRIM25 than in control cells. Furthermore, siRNA-mediated silencing of TRIM25 increased the production of viral progeny. These results help elucidate the molecular mechanisms underlying the host response to DTMUV infection and suggest potential control measures for DTMUV outbreaks.

Sustained Attention Deficits in Adults With Juvenile-Onset Type 1 Diabetes Mellitus.

OBJECTIVE: This study aimed to investigate whether patients with juvenile-onset type 1 diabetes mellitus (T1DM) have poorer sustained attention than their counterparts with adult-onset T1DM, and whether there is a relationship between diabetes-related variables and sustained attention. METHODS: This study included 76 participants with juvenile-onset T1DM, 68 participants with adult-onset T1DM, and 85 healthy controls (HCs). All participants completed the Sustained Attention to Response Task, Beck Depression Inventory-II, and the Chinese version of the Wechsler Adult Intelligence Scale. RESULTS: The juvenile-onset group showed more omission errors (p = .007) than the adult-onset group and shorter reaction time (p = .005) than HCs, whereas the adult-onset group showed no significant differences compared with HCs. Hierarchical linear regression analysis revealed that the age of onset was associated with omission errors in T1DM participants (ß = -0.275, t = -2.002, p = .047). In the juvenile-onset group, the omission error rate were associated with the history of severe hypoglycemia (ß = 0.225, t = 1.996, p = .050), whereas reaction time was associated with the age of onset (ß = -0.251, t = -2.271, p = .026). Fasting blood glucose levels were significantly associated with reaction time in both the juvenile-onset and adult-onset groups (ß = -0.236, t = -2.117, p = .038, and ß = 0.259, t = 2.041, p = .046, respectively). CONCLUSIONS: Adults with juvenile-onset T1DM have sustained attention deficits in contrast to their adult-onset counterparts, suggesting that the disease adversely affects the developing brain. Both the history of severe hypoglycemia and fasting blood glucose levels are factors associated with sustained attention impairment. Early diagnosis and treatment in juvenile patients are required to prevent the detrimental effects of diabetes.

Transcriptome analysis reveals new insight of duck Tembusu virus (DTMUV)-infected DF-1 cells.

Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused huge economic losses to the duck industry in China since 2010. Moreover, the infection has spread rapidly, resulted in a potential public health concern. To improve our understanding of the host cellular responses to virus infection and the pathogenesis of DTMUV infection, we used RNA-Seq to detect the gene changes in DF-1 cells infected and mock-infected with DTMUV. A total of 663 differentially-expressed genes (DEGs) were identified in DTMUV-infected compared with mock-infected DF-1 cells at 24 h post-infection (hpi), among which 590 were up regulated and 73 were down regulated. Gene Ontology analysis indicated that the DEGs were mainly involved in cellular process, immune system processes, metabolic processes, and signal-organism process. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the DEGs were mainly involved in several signaling pathways such as Toll-like receptor signaling, Jak-STAT signaling, RIG-I-like receptor signaling and AGE-RAGE signaling pathway. Moreover, some selected DEGs were further confirmed by real-time PCR and the results were consistent with the sequencing data. To our knowledge, this study is the first to analyze the transcriptomic change in DF-1 cells following DTMUV infection. We believe that our research provides useful information in better understanding the host response to DTMUV infection and the inherent mechanism of DTMUV replication and pathogenicity.

Analysis of the microRNA expression profiles of chicken dendritic cells in response to H9N2 avian influenza virus infection.

MicroRNA (miRNA) plays a key role in virus-host interactions. Here, we employed deep sequencing technology to determine cellular miRNA expression profiles in chicken dendritic cells infected with H9N2 avian influenza virus (AIV). A total of 66 known and 36 novel miRNAs were differently expressed upon H9N2 infection, including 72 up-regulated and 30 down-regulated miRNAs. Functional analysis showed that the predicted targets of these miRNAs were significantly enriched in several pathways including endocytosis, notch, lysosome, p53, RIG-I-like and NOD-like receptor signaling pathways. These data provide valuable information for further investigating the roles of miRNA in AIV pathogenesis and host defense response.

Tembusu virus enters BHK-21 cells through a cholesterol-dependent and clathrin-mediated endocytosis pathway.

Tembusu virus (TMUV) is a newly emerging flavivirus and has caused significant economic loss to the poultry industry in China. To date, the entry of TMUV into host cells remains poorly understood. Here, the mechanism of TMUV entry into BHK-21 cells was investigated. The depletion of cellular cholesterol by methyl-ß-cyclodextrin led to a significant decline in the titers and RNA levels of the infectious TMUV. This reduction was restored by supplementation of exogenous cholesterol. Membrane cholesterol depletion mainly blocked viral internalization but not attachment. However, viral infection was unaffected by genistein treatment or caveolin-1 silencing by small interfering RNA. In addition, clathrin-mediated endocytosis might be utilized in TMUV entry given that the viral infection was inhibited by knockdown of clathrin heavy chain and treatment of chlorpromazine (CPZ). Moreover, the number of internalized virus particles decreased under CPZ treatment. Dynasore inhibited TMUV entry suggesting a role for dynamin. Our results reveal that TMUV entry into BHK-21 cells is dependent on cholesterol, clathrin and dynamin but not caveolae.

Peptide inhibitors of tembusu virus infection derived from the envelope protein.

The outbreak and spread of Tembusu virus (TMUV) has caused very large losses in the waterfowl-breeding industry since 2010. The viral envelope (E) protein, the principal surface protein of viral particles, plays a vital role in viral entry and fusion. In this study, two peptides derived from domain II (DII) and the stem of the TMUV envelope protein, TP1 and TP2, respectively, were tested for their antiviral activity. TP1 and TP2 inhibited TMUV infection in BHK-21 cells, and their 50% inhibitory concentrations (IC50) were 14.19 mg/L and 7.64 mg/L, respectively. Viral inhibition assays in different cell lines of avian origin showed that the inhibitory effects of TP1 and TP2 are not cell type dependent. Moreover, TP2 also exhibited inhibitory activity against Japanese encephalitis virus (JEV) infection. The two peptides inhibited antibody-mediated TMUV infection of duck peripheral blood lymphocytes. Co-immunoprecipitation assays and indirect enzyme-linked immunosorbent assays (ELISAs) indicated that both peptides interact with the surface of the TMUV virion. RNase digestion assays confirmed the release of viral RNA following incubation with TP1, while incubation with TP1 or TP2 interfered with the binding between TMUV and cells. Taken together, these results show that TP1 and TP2 may be developed into antiviral treatments against TMUV infection.

Global gene expression analysis data of chicken dendritic cells infected with H9N2 avian influenza virus.

This data article reports the global gene expression analysis data of chicken DCs infected with H9N2 avian influenza virus (AIV) compared with mock infection. The differentially expressed genes (DEGs), and the data of GO enrichment analysis and KEGG pathway analysis for DEGs were reported here. In addition, some of these DEGs associated with innate immune response and antigen presentation were also verified by qPCR. The replication of H9N2 AIV in DCs, and the viability kinetic of DCs during H9N2 AIV infection, and the primers for qPCR were also reported in this data article. The data presented here was used on the research article entitled "Transcriptomic profile of chicken bone marrow-derive dendritic cells in response to H9N2 avianinfluenza A virus".

Transcriptomic profile of chicken bone marrow-derive dendritic cells in response to H9N2 avian influenza A virus.

Avian influenza subtype H9N2 infection is a mild but highly contagious disease that is associated with a decrease in the efficacy of vaccine interventions, and an increase in susceptibility to secondary infections in poultry. However, the immune evasion mechanism of H9N2 avian influenza viruses (AIVs) in chickens is poorly understood. Dendritic cells (DCs) are immune cells of major importance, involved in innate immune responses against viruses, but also in the setting of adaptive immune response due to their high ability to present viral antigen. Therefore, in the present study we used high-throughput RNA-sequencing technology at the transcriptome level to identify the differentially expressed genes (DEGs) between chicken DCs infected with H9N2 virus and mock-infected DCs. We identified 4151 upregulated DEGs and 2138 downregulated DEGs. Further enrichment analysis showed that the upregulated DEGs were enriched in the biological processes mainly involved in signal transduction, transmembrane transport, and innate immune/inflammatory responses. In contrast, the downregulated DEGs were associated with the biological processes mainly including metabolic process, and MHC class I antigen processing and presentation. In addition, 49 of these immune-related DEGs were validated by reverse transcription quantitative PCR (RT-qPCR). Collectively, these data suggest that H9N2 virus infection may enhance the signal transduction, and innate immune responses in chicken DCs, but impair their metabolic functions and antigen-presenting responses, which provide helpful insight into the pathogenesis of H9N2 AIVs in chickens and managing this infection in poultry farms.

The ubiquitin-proteasome system is necessary for the replication of duck Tembusu virus.

Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused massive economic losses to the duck industry in China. The cellular factors required for DTMUV replication have been poorly studied. The ubiquitin-proteasome system (UPS), the major intracellular proteolytic pathway, mediates diverse cellular processes, including endocytosis and signal transduction, which may be involved in the entry of virus. In the present study, we explored the interplay between DTMUV replication and the UPS in BHK-21 cells and found that treatment with proteasome inhibitor (MG132 and lactacystin) significantly decreased the DTMUV progency at the early infection stage. We further revealed that inhibition of the UPS mainly occurs on the level of viral protein expression and RNA transcription. In addition, using specific siRNAs targeting ubiquitin reduces the production of viral progeny. In the presence of MG132 the staining for the envelope protein of DTMUV was dramatically reduced in comparison with the untreated control cells. Overall, our observations reveal an important role of the UPS in multiple steps of the DTMUV infection cycle and identify the UPS as a potential drug target to modulate the impact of DTMUV infection.

The unfolded protein response induced by Tembusu virus infection.

BACKGROUND: Tembusu virus (TMUV), classified in the genus Flavivirus, causes reduced egg production and neurological problems in poultry. Flavivirus replication depends on the host endoplasmic reticulum (ER) and induces ER stress that leads to activation of the cellular unfolded protein response (UPR), an important signalling pathway that regulates many biological functions involved in viral pathogenesis and innate immunity. However, the mechanism of TMUV-induced UPR activation remains unclear. RESULTS: In this study, we systematically investigated the three UPR pathways in TMUV-infected BHK-21 cells. Our results showed that expression of glucose-related protein 78 (GRP78) and GRP94 was upregulated during the course of TMUV infection. We then demonstrated that TMUV activated the PERK pathway in the early stage of infection, resulting in upregulation of ATF4, GADD34 and CHOP, with CHOP induction leading to caspase-3 activation. We also found the IRE1 pathway to be activated, leading to splicing of X box binding protein 1 (XBP1) mRNA and enhanced expression of p58IPK. Finally, we observed increased expression of ATF6 and activity of ER stress-response elements, suggesting stimulation of the ATF6 pathway. In addition, ATF6 pathway activation correlated with the induction of downstream chaperones calnexin, calreticulin, ERp57 and PDI. UPR activity was also observed by the marked elevation in GRP78 and sXBP1 levels in TMUV-infected DF-1 cells. CONCLUSIONS: This is the first report that TMUV infection-induced ER stress activates three branches of the UPR, and these results lay the foundation for elucidating the pathogenesis of TMUV and understanding the inherent mechanism of TMUV infection as well as the host response.