Pristimerin exhibits anti-cancer activity by inducing ER stress and AKT/GSK3ß pathway through increasing intracellular ROS production in human esophageal cancer cells.

Pristimerin (Pris), a bioactive triterpenoid compound extracted from the Celastraceae and Hippocrateaceae families, has been reported to exhibit an anti-cancer property on various cancers. However, the effects of Pris on esophageal cancer are poorly investigated. This current study sought to explore the activity and underlying mechanism of Pris against human esophageal squamous cell carcinoma (ESCC) cells. We demonstrated that Pris showed cytotoxicity in TE-1 and TE-10 ESCC cell lines, and significantly inhibited cell viability in a concentration dependent manner. Pris induced G0/G1 phase arrest and triggered apoptosis. It was also observed that the intracellular ROS level was remarkedly increased by Pris treatment. Besides, the function of Pris mediating the activation of ER stress and the inhibition of AKT/GSK3ß signaling pathway in TE-1 and TE-10 cells was further confirmed, which resulted in cell growth inhibition. And moreover, we revealed that all of the above pathways were regulated through ROS generation. In conclusion, our findings suggested that Pris might be considered as a novel natural compound for the developing anti-cancer drug candidate for human esophageal cancer.

(-)-Epicatechin gallate ameliorates cyprodinil-induced cardiac developmental defects through inhibiting aryl hydrocarbon receptor in zebrafish.

BACKGROUND: Cyprodinil is a widely used fungicide with broad-spectrum activity, but it has been associated with cardiac abnormalities. (-)-Epicatechin gallate (ECG), a natural polyphenolic compound, has been shown to possess protective properties in cardiac development. METHODS: In this study, we investigated whether ECG could mitigate cyprodinil-induced heart defects using zebrafish embryos as a model. Zebrafish embryos were exposed to cyprodinil with or without ECG. RESULTS: Our results demonstrated that ECG significantly improved the survival rate, embryo movement, and hatching delay induced by cyprodinil. Furthermore, ECG effectively ameliorated cyprodinil-induced cardiac developmental toxicity, including pericardial anomaly and impairment of cardiac function. Mechanistically, ECG attenuated the cyprodinil-induced alterations in mRNA expression related to cardiac development, such as amhc, vmhc, tbx5, and gata4, as well as calcium ion channels, such as ncx1h, atp2a2a, and cdh2. Additionally, ECG was found to inhibit the activity of the aryl hydrocarbon receptor (AhR) signaling pathways induced by cyprodinil. CONCLUSIONS: In conclusion, our findings provide evidence for the protective effects of ECG against cyprodinil-induced cardiac developmental toxicity, mediated through the inhibition of AhR activity. These findings contribute to a better understanding of the regulatory mechanisms and safe utilization of pesticide, such as cyprodinil.

Survival benefits of human papillomavirus 16 infection in patients with esophageal squamous cell carcinoma undergoing chemoradiotherapy: A retrospective cohort study.

The role of human papillomavirus 16 (HPV 16) in esophageal squamous cell carcinoma (ESCC) remains uncertain. Therefore, this study aimed to investigate the prevalence of HPV 16 in patients with ESCC and its impact on theirprognosis. HPV 16 was detected using FISH, and TP53 status was evaluated via immunohistochemistry. The factors influencing prognosis were ananalyzed using the Log-rank test and Cox regression analyses. Among 178 patients with ESCC, 105 and 73 patients were categorized into concurrent chemoradiotherapy (CCRT) and postoperative chemoradiotherapy (POCRT) cohorts, respectively. Among 178 patients, 87 (48.87%) tested positive for HPV 16. Log-rank tests revealed that the overall survival (OS) of patients with ESCC who were HPV 16-positive was longer than that of those who were HPV 16-negative (median OS: 57 months vs. 27 months, p < 0.01**). HPV 16 infection and TP53 mutation status were identified as independent events. The OS of patients with mutant TP53 who were HPV 16-positive was longer than that of those who were HPV 16-negative in both CCRT and POCRT cohorts (p = 0.002** for CCRT cohorts and p = 0.0023** for POCRT cohorts). Conversely, HPV 16 infection had no effect on OS in the wild-type TP53 subgroup (p = 0.13 and 0.052 for CCRT and POCRT cohorts, respectively). As a conclusion, the positive rate of HPV 16 in ESCC in this study was 48.87% (87/178). Among the patients with ESCC who had TP53 mutation, those who were HPV 16-positive exhibited a better prognosis than those who were HPV 16-negative.

Multi-omics cluster defines the subtypes of CRC with distinct prognosis and tumor microenvironment.

BACKGROUND: Colorectal cancer (CRC) is a complex malignancy characterized by diverse molecular profiles, clinical outcomes, and limited precision in prognostic markers. Addressing these challenges, this study utilized multi-omics data to define consensus molecular subtypes in CRC and elucidate their association with clinical outcomes and underlying biological processes. METHODS: Consensus molecular subtypes were obtained by applying ten integrated multi-omics clustering algorithms to analyze TCGA-CRC multi-omics data, including mRNA, lncRNA, miRNA, DNA methylation CpG sites, and somatic mutation data. The association of subtypes with prognoses, enrichment functions, immune status, and genomic alterations were further analyzed. Next, we conducted univariate Cox and Lasso regression analyses to investigate the potential prognostic application of biomarkers associated with multi-omics subtypes derived from weighted gene co-expression network analysis (WGCNA). The function of one of the biomarkers MID2 was validated in CRC cell lines. RESULTS: Two CRC subtypes linked to distinct clinical outcomes were identified in TCGA-CRC cohort and validated with three external datasets. The CS1 subtype exhibited a poor prognosis and was characterized by higher tumor-related Hallmark pathway activity and lower metabolism pathway activity. In addition, the CS1 was predicted to have less immunotherapy responder and exhibited more genomic alteration compared to CS2. Then a prognostic model comprising five genes was established, with patients in the high-risk group showing substantial concordance with the CS1 subtype, and those in the low-risk group with the CS2 subtype. The gene MID2, included in the prognostic model, was found to be correlated with epithelial-mesenchymal transition (EMT) pathway and distinct DNA methylation patterns. Knockdown of MID2 in CRC cells resulted in reduced colony formation, migration, and invasion capacities. CONCLUSION: The integrative multi-omics subtypes proposed potential biomarkers for CRC and provided valuable knowledge for precision oncology.

USP11 promotes glycolysis by regulating HIF-1α stability in hepatocellular carcinoma.

Understanding the mechanisms underlying metastasis in hepatocellular carcinoma (HCC) is crucial for developing new therapies against this fatal disease. Deubiquitinase ubiquitin-specific protease 11 (USP11) belongs to the deubiquitinating family and has previously been reported to play a critical role in cancer pathogenesis. Although it has been established that USP11 can facilitate the metastasis and proliferation ability of HCC, the underlying regulatory mechanisms are poorly understood. The primary objective of this research was to reveal hitherto undocumented functions of USP11 during HCC progression, especially those related to metabolism. Under hypoxic conditions, USP11 was found to significantly impact the glycolysis of HCC cells, as demonstrated through various techniques, including RNA-Seq, migration and colony formation assays, EdU and co-immunoprecipitation. Interestingly, we found that USP11 interacted with the HIF-1α complex and maintained HIF-1α protein stability by removing ubiquitin. Moreover, USP11/HIF-1α could promote glycolysis through the PDK1 and LDHA pathways. In general, our results demonstrate that USP11 promotes HCC proliferation and metastasis through HIF-1α/LDHA-induced glycolysis, providing new insights and the experimental basis for developing new treatments for this patient population.

Knockdown of SQLE promotes CD8+ T cell infiltration in the tumor microenvironment.

Cholesterol biosynthesis and metabolism are critical aspects that shape the process of tumor development and associated microenvironmental conditions owing to the ability of cholesterol to drive tumor growth and invasion. Squalene Epoxidase (SQLE) is the second rate-limiting enzyme involved in the synthesis of cholesterol. The functional role of SQLE within the tumor microenvironment, however, has yet to be established. Here we show that SQLE is distinctively expressed across most types of cancer, and the expression level is highly correlated with tumor mutation burden and microsatellite instability. Accordingly, SQLE was identified as a prognostic risk factor in cancer patients. In addition, we observed a negative correlation between SQLE expression and immune cell infiltration across multiple cancers, and murine xenograft model further confirmed that SQLE knockdown was associated with enhanced intratumoral CD8+ T cell infiltration. Using next-generation sequencing, we identified 410 genes distinctively expressed in tumors exhibiting SQLE inhibition. KEGG and GO analysis further verified that SQLE altered the immune response in the tumor microenvironment. Furthermore, we found that the metabolism and translation of proteins is the main binding factor with SQLE. Our findings ascertain that SQLE is a potential target in multiple cancers and suppressing SQLE establishes an essential mechanism for shaping tumor microenvironment.

The AEG-1-USP10-PARP1 axis confers radioresistance in esophageal squamous cell carcinoma via facilitating homologous recombination-dependent DNA damage repair.

Radiotherapy is the standard adjuvant treatment for esophageal squamous cell carcinoma (ESCC), yet radioresistance remains a major obstacle leading to treatment failure and unfavorable prognosis. Previous reports have demonstrated the involvement of astrocyte elevated gene-1 (AEG-1) in tumorigenesis and progression of multiple malignancies. Nevertheless, the precise role of AEG-1 in the radioresistance of ESCC remains elusive. Here, we unveiled a strong correlation between aberrant AEG-1 gene overexpression and malignant progression as well as adverse prognosis in ESCC patients. Moreover, both in vitro and in vivo investigations revealed that AEG-1 significantly alleviated irradiation-induced DNA damage and enhanced radiation resistance in ESCC cells. Mechanistically, AEG-1 recruited the deubiquitinase USP10 to remove the K48-linked polyubiquitin chains at the Lys425 of PARP1, thus preventing its proteasomal degradation. This orchestrated process facilitated homologous recombination-mediated DNA double-strand breaks (DSBs) repair, culminating in mitigated DNA damage and acquired radioresistance in ESCC cells. Notably, PARP1 overexpression reversed the radiosensitizing effect caused by AEG-1 deficiency. Collectively, these findings shed new light on the mechanism of ESCC radioresistance, providing potential therapeutic targets to enhance the efficacy of radiotherapy in ESCC.

IHGA: An interactive web server for large-scale and comprehensive discovery of genes of interest in hepatocellular carcinoma.

Mining gene expression data is valuable for discovering novel biomarkers and therapeutic targets in hepatocellular carcinoma (HCC). Although emerging data mining tools are available for pan-cancer-related gene data analysis, few tools are dedicated to HCC. Moreover, tools specifically designed for HCC have restrictions such as small data scale and limited functionality. Therefore, we developed IHGA, a new interactive web server for discovering genes of interest in HCC on a large-scale and comprehensive basis. Integrative HCC Gene Analysis (IHGA) contains over 100 independent HCC patient-derived datasets (with over 10,000 tissue samples) and more than 90 cell models. IHGA allows users to conduct a series of large-scale and comprehensive analyses and data visualizations based on gene mRNA levels, including expression comparison, correlation analysis, clinical characteristics analysis, survival analysis, immune system interaction analysis, and drug sensitivity analysis. This method notably enhanced the richness of clinical data in IHGA. Additionally, IHGA integrates artificial intelligence (AI)-assisted gene screening based on natural language models. IHGA is free, user-friendly, and can effectively reduce time spent during data collection, organization, and analysis. In conclusion, IHGA is competitive in terms of data scale, data diversity, and functionality. It effectively alleviates the obstacles caused by HCC heterogeneity to data mining work and helps advance research on the molecular mechanisms of HCC.

The diagnostic potential of two exosome-derived circRNAs for papillary thyroid cancer.

BACKGROUND: As a critical component of exosomes, circular RNAs (circRNAs) have shown great value in cancer diagnosis. This study aimed to identify circRNAs in exosomes for the diagnosis of PTC (papillary thyroid carcinoma). METHODS: We selected hsa_circ_0082002 and hsa_circ_0003863 based on circRNA microarray. The levels of exosomal hsa_circ_0082002 and hsa_circ_0003863 in the sera of healthy control (n = 68), benign thyroid tumors (n = 60), and PTC without and with Hashimoto's thyroiditis (n = 164) were quantified by qPCR (quantitative polymerase chain reaction). Receiver operating characteristic analyses were conducted to evaluate the diagnostic sensitivity and specificity. Bioinformatics databases were used to predict the microRNAs and proteins binding with hsa_circ_0082002 and hsa_circ_0003863. RESULTS: The levels of exosomal hsa_circ_0082002 and hsa_circ_0003863 were positively associated and statistically increased in PTC compared to healthy and benign thyroid tumors. Intriguingly, higher levels of exosomal hsa_circ_0082002 and hsa_circ_0003863 were positively correlated with lymph node metastasis and vascular invasion in PTC. Further stability tests show that exosomal hsa_circ_0082002 and hsa_circ_0003863 could exist stably in sera treated by several freeze-thaw cycles at -20 °C and with a storage time shorter than 24 h at 4 °C. Furthermore, hsa_circ_0082002 and hsa_circ_0003863 were predicted to interact with microRNAs and proteins, suggesting that hsa_circ_0082002 and hsa_circ_0003863 might contribute to the occurrence and progression of PTC through interacting with microRNAs and RNA binding proteins. CONCLUSION: Collectively, we identified two PTC-related circRNAs incorporated in exosomes and uncovered their potential as tumor markers to diagnose PTC, in particular, more aggressive PTC.

An artificial neural network-based radiomics model for predicting the radiotherapy response of advanced esophageal squamous cell carcinoma patients: a multicenter study.

Radiotherapy benefits patients with advanced esophageal squamous cell carcinoma (ESCC) in terms of symptom relief and long-term survival. In contrast, a substantial proportion of ESCC patients have not benefited from radiotherapy. This study aimed to establish and validate an artificial neural network-based radiomics model for the pretreatment prediction of the radiotherapy response of advanced ESCC by using integrated data combined with feasible baseline characteristics of computed tomography. A total of 248 patients with advanced ESCC who underwent baseline CT and received radiotherapy were enrolled in this study and were analyzed by two types of radiomics models, machine learning and deep learning. As a result, the Att. Resnet50 pretrained network model indicated superior performance, with AUCs of 0.876, 0.802 and 0.732 in the training, internal validation, and external validation cohorts, respectively. Similarly, our Att. Resnet50 pretrained network model showed excellent calibration and significant clinical benefit according to the C index and decision curve analysis. Herein, a novel pretreatment radiomics model was established based on deep learning methods and could be used for radiotherapy response prediction in advanced ESCC patients, thus providing reliable evidence for therapeutic decision-making.

Four m6A RNA Methylation Gene Signatures and Their Prognostic Values in Lung Adenocarcinoma.

Introduction: Evidence demonstrates that N6-methyladenosine (m6A) modification plays an increasingly important role in the development of tumors. The aim of this study is to explore the expression of m6A-related regulators in lung adenocarcinoma, identify the effect of altered key factors modified by m6A on the prognosis of patients with lung adenocarcinoma. Methods: A comprehensive analysis of m6A-related gene expressions in patients with lung adenocarcinoma based on The Cancer Genome Atlas database (TCGA) and the CBioPortal database. A prognostic risk score was established based on a linear combination of 4 key gene expression levels using the regression coefficients of the multivariate Cox regression models. Immunohistochemical staining analysis was performed to validate the relationship between the protein expression level of m6A regulators and the prognosis of patients retrospectively. The possible mechanism and prospective therapeutic targets of these key m6A molecules were explored by the M6A2Target database and the CMAP database. Results: Mutation pattern analysis revealed that 32% of 656 patients had genetic alterations. Four genes (writer: methyltransferase like 3 [METTL3] and three readers: insulin like growth factor 2 mRNA binding protein 2 [IGF2BP2], heterogeneous nuclear ribonucleoprotein C [HNRNPC], and heterogeneous nuclear ribonucleoprotein A2/B1 [HNRNPA2B1]) were selected to construct a survival risk prediction model and the results of immunohistochemical staining showed that the expression of these four m6A genes was significantly different between lung adenocarcinoma tissues and normal lung tissues (p < .01). The possible downstream genes and prospective therapeutic targets of these four m6A key molecules were discovered. Conclusion: These four m6A RNA methylation regulators may be effective prognostic and diagnostic factors which can provide auxiliary diagnosis and prognosis of lung adenocarcinoma.

2D-ultrathin MXene/DOXjade platform for iron chelation chemo-photothermal therapy.

An increased demand for iron is a hallmark of cancer cells and is thought necessary to promote high cell proliferation, tumor progression and metastasis. This makes iron metabolism an attractive therapeutic target. Unfortunately, current iron-based therapeutic strategies often lack effectiveness and can elicit off-target toxicities. We report here a dual-therapeutic prodrug, DOXjade, that allows for iron chelation chemo-photothermal cancer therapy. This prodrug takes advantage of the clinically approved iron chelator deferasirox (ExJade®) and the topoisomerase 2 inhibitor, doxorubicin (DOX). Loading DOXjade onto ultrathin 2D Ti3C2 MXene nanosheets produces a construct, Ti 3 C 2 -PVP@DOXjade, that allows the iron chelation and chemotherapeutic functions of DOXjade to be photo-activated at the tumor sites, while potentiating a robust photothermal effect with photothermal conversion efficiencies of up to 40%. Antitumor mechanistic investigations reveal that upon activation, Ti 3 C 2 -PVP@DOXjade serves to promote apoptotic cell death and downregulate the iron depletion-induced iron transferrin receptor (TfR). A tumor pH-responsive iron chelation/photothermal/chemotherapy antitumor effect was achieved both in vitro and in vivo. The results of this study highlight what may constitute a promising iron chelation-based phototherapeutic approach to cancer therapy.

The E2F1/USP11 positive feedback loop promotes hepatocellular carcinoma metastasis and inhibits autophagy by activating ERK/mTOR pathway.

Deubiquitinase ubiquitin-specific protease 11 (USP11), a member of the deubiquitinating family, plays an important but still controversial role in cancer development. Namely, USP11 has been shown to promote the proliferation and metastasis of hepatocellular carcinoma (HCC), but the underlying molecular basis is poorly understood. This study aimed to unravel novel functions of USP11 in HCC, especially those related to autophagy. Here, EdU, migration and colony formation assays, and mouse models showed that USP11 played a crucial role in HCC cell proliferation and metastasis in vitro and in vivo. Results from co-immunoprecipitation and ubiquitination assays demonstrated that USP11 interacted with E2F1 and maintained E2F1 protein stability by removing its ubiquitin. Notably, E2F1 regulated USP11 expression at the transcriptional level. Thus, the E2F1/USP11 formed a positive feedback loop to promote the proliferation and migration of HCC cells. Moreover, E2F1/USP11 inhibited autophagy by regulating ERK/mTOR pathway. In addition, the combination treatment inhibition of USP11 and autophagy enhanced the apoptosis of HCC cells and inhibited the tumor growth in mice more effective than either treatment alone. Taken together, these results indicate that the E2F1/USP11 signal axis promotes HCC proliferation and metastasis and inhibits autophagy, which provides an experimental basis for the treatment of HCC.

Hypoxia associated multi-omics molecular landscape of tumor tissue in patients with hepatocellular carcinoma.

The present study was designed to update the knowledge about hypoxia-related multi-omic molecular landscape in hepatocellular carcinoma (HCC) tissues. Large-size HCC datasets from multiple centers were collected. The hypoxia exposure of tumor tissue from patients in 10 HCC cohorts was estimated using a novel HCC-specific hypoxia score system constructed in our previous study. A comprehensive bioinformatical analysis was conducted to compare hypoxia-associated multi-omic molecular features in patients with a high hypoxia score to a low hypoxia score. We found that patients with different exposure to hypoxia differed significantly in transcriptomic, genomic, epigenomic, and proteomic alterations, including differences in mRNA, microRNA (miR), and long non-coding RNA (lncRNA) expression, differences in copy number alterations (CNAs), differences in DNA methylation levels, differences in RNA alternative splicing events, and differences in protein levels. HCC survival- associated molecular events were identified. The potential correlation between molecular features related to hypoxia has also been explored, and various networks have been constructed. We revealed a particularly comprehensive hypoxia-related molecular landscape in tumor tissues that provided novel evidence and perspectives to explain the role of hypoxia in HCC. Clinically, the data obtained from the present study may enable the development of individualized treatment or management strategies for HCC patients with different levels of hypoxia exposure.

Scalable Fabrication of Metallopolymeric Superstructures for Highly Efficient Removal of Methylene Blue.

Metallopolymeric superstructures (MPS) are hybrid functional materials that find wide applications in environmental, energy, catalytic and biomedical-related scenarios, while their fabrication usually suffers from the complicated polymerization between monomeric ligands and metal ions. In this work, we have developed a facile one-step protocol to fabricate metallopolymeric superstructures with different morphology including nanospheres, nanocubes, nanorods, and nanostars for environmental remediation application. Specifically, we have firstly synthesized the amphiphilic block copolymers (BCP) bearing hydrophobic aromatic backbone and hydrophilic pendent carboxylic/sulfonic groups, which have been subsequently transformed into MPS via the metal ions mediated self-assembly in mixed solution of dimethylformamide (DMF) and H2O. Based on SEM, FTIR, XRD and XPS characterization, we have revealed that the fine morphology and condensed structures of MPS can be modulated via the metal ions and BCP concentration, and the obtained MPS can be employed as efficient adsorbents for the removal of methylene blue with maximum adsorption capacity approaching 936.13 mg/g.

Generation of a broadly reactive influenza H1 antigen using a consensus HA sequence.

H1N1, one of the most prevalent influenza A virus subtypes affecting the human population, can cause infections varying from mild respiratory syndrome to severe pneumonia. The current H1N1 vaccine needs to be updated annually and does not protect against future outbreaks. Here, we downloaded 2,656 HA protein sequences of human H1N1 viruses from the NCBI influenza database (up to the date of Aug. 2012) and constructed a phylogenetic tree of these H1 proteins via the neighbor-joining method using MEGA 5.0 software. A consensus H1 protein (CH1) was generated and was further modified with published conserved T-cell and B-cell epitopes. Interestingly, this CH1 protein is genetically similar to an H1 isolate obtained during the 1980s (A/Memphis/7/1980), indicating that a universal HA antigen may exist in nature. Vaccination with a DNA vaccine expressing CH1 elicited broadly reactive T-cell and B-cell responses to heterologous H1N1 viruses, though this vaccine did not successfully neutralize pdm09 H1N1 viruses. A combination of CH1 and pdm09 HA in a DNA vaccination neutralized pdm09 H1N1 viruses and protected mice from lethal infections by all representative H1N1 viruses. Moreover, a recombinant chimeric PR8-CH1 virus carrying HA sequence of the consensus H1 and all other seven genes from the PR8 strain was highly attenuated in mice, with a lethal dose (LD50) of more than 106 pfu. Vaccination with PR8-CH1 virus provided complete protection against infections by heterologous H1N1 strains. Taken together, a universal H1 antigen, CH1, was developed by constructing a consensus HA sequence, and the PR8-CH1 virus containing this consensus sequence elicited broadly protective immunity against heterologous H1N1 viruses.

A Vero-cell-adapted vaccine donor strain of influenza A virus generated by serial passages.

A cell culture-based vaccine production system is preferred for the large-scale production of influenza vaccines and has advantages for generating vaccines against highly pathogenic influenza A viruses. Vero cells have been widely used in human vaccine manufacturing, and the safety of these cells has been well demonstrated. However, the most commonly used influenza-vaccine donor virus, A/Puerto Rico/8/1934 (PR8) virus, does not grow efficiently in Vero cells. Therefore, we adapted the PR8 virus to Vero cells by continuous passaging, and a high-growth strain was obtained after 20 passages. Sequence analysis and virological assays of the adapted strain revealed that mutations in four viral internal genes (NP, PB1, PA and NS1) were sufficient for adaptation. The recombinant virus harboring these mutations (PR8-4mut) displayed accelerated viral transport into the nucleus and increased RNP activity. Importantly, the PR8-4mut could serve as a backbone donor virus to support the growth of the H7N1, H9N2 and H5N1 avian viruses and the H1N1 and H3N2 human viruses in Vero cells without changing its pathogenicity in either chicken embryos or mice. Thus, our work describes the generation of a Vero-adapted, high-yield PR8-4mut virus that may serve as a promising candidate for an influenza-vaccine donor virus.

Fully human broadly neutralizing monoclonal antibodies against influenza A viruses generated from the memory B cells of a 2009 pandemic H1N1 influenza vaccine recipient.

Whether the 2009 pandemic H1N1 influenza vaccine can induce heterosubtypic cross-protective anti-hemagglutinin (HA) neutralizing antibodies is an important issue. We obtained a panel of fully human monoclonal antibodies from the memory B cells of a 2009 pandemic H1N1 influenza vaccine recipient. Most of the monoclonal antibodies targeted the HA protein but not the HA1 fragment. Among the analyzed antibodies, seven mAbs exhibited neutralizing activity against several influenza A viruses of different subtypes. The conserved linear epitope targeted by the neutralizing mAbs (FIEGGWTGMVDGWYGYHH) is part of the fusion peptide on HA2. Our work suggests that a heterosubtypic neutralizing antibody response primarily targeting the HA stem region exists in recipients of the 2009 pandemic H1N1 influenza vaccine. The HA stem region contains various conserved neutralizing epitopes with the fusion peptide as an important one. This work may aid in the design of a universal influenza A virus vaccine.

Amino acids 473V and 598P of PB1 from an avian-origin influenza A virus contribute to polymerase activity, especially in mammalian cells.

It has been reported that the avian-origin influenza A virus PB1 protein (avian PB1) enhances influenza A virus polymerase activity in mammalian cells when it replaces the human-origin PB1 protein (human PB1). Characterization of the amino acid residues that contribute to this enhancement is needed. In this study, it was found that PB1 from an avian-origin influenza A virus [A/Cambodia/P0322095/2005, H5N1 (Cam)] could enhance the polymerase activity of an attenuated human isolated virus, A/WSN/33, carrying the PB2 K627E mutation (WSN627E) in vitro. Furthermore, 473V and 598P in the Cam PB1 were identified as the residues responsible for this enhanced activity. The results from recombinant virus experiments demonstrated the contribution of PB1 amino acids 473V and 598P to polymerase activity in mammalian cells and in mice. Interestingly, 473V is conserved in pH1N1 viruses from the 2009 pandemic. Substitution of 473V by leucine in pH1N1 PB1 led to a decreased viral polymerase activity and a lower growth rate in mammalian cells, suggesting that the PB1 473V also plays a role in maintaining efficient virus replication of the pH1N1 virus. Thus, it was concluded that two amino acids in avian-origin PB1, 473V and 598P, contribute to the polymerase activity of the H5N1 virus, especially in mammalian cells, and that 473V in PB1 also contributes to efficient replication of the pH1N1 strain.

Efficient induction of CD25- iTreg by co-immunization requires strongly antigenic epitopes for T cells.

BACKGROUND: We previously showed that co-immunization with a protein antigen and a DNA vaccine coding for the same antigen induces CD40 low IL-10 high tolerogenic DCs, which in turn stimulates the expansion of antigen-specific CD4+CD25-Foxp3+ regulatory T cells (CD25- iTreg). However, it was unclear how to choose the antigen sequence to maximize tolerogenic antigen presentation and, consequently, CD25- iTreg induction. RESULTS: In the present study, we demonstrated the requirement of highly antigenic epitopes for CD25- iTreg induction. Firstly, we showed that the induction of CD25- iTreg by tolerogenic DC can be blocked by anti-MHC-II antibody. Next, both the number and the suppressive activity of CD25- iTreg correlated positively with the overt antigenicity of an epitope to activate T cells. Finally, in a mouse model of dermatitis, highly antigenic epitopes derived from a flea allergen not only induced more CD25- iTreg, but also more effectively prevented allergenic reaction to the allergen than did weakly antigenic epitopes. CONCLUSIONS: Our data thus indicate that efficient induction of CD25- iTreg requires highly antigenic peptide epitopes. This finding suggests that highly antigenic epitopes should be used for efficient induction of CD25- iTreg for clinical applications such as flea allergic dermatitis.