Xijiao Dihuang decoction combined with Yinqiao powder promotes autophagy-dependent ROS decrease to inhibit ROS/NLRP3/pyroptosis regulation axis in influenza virus infection.

BACKGROUND: Influenza viral pneumonia is a common complication after influenza virus infection. Xijiao Dihuang Decoction combined with Yinqiao Powder (XDY) is effective on improving influenza viral pneumonia. PURPOSE: This study further explores the anti-inflammatory mechanism of XDY in the treatment of influenza viral pneumonia. STUDY DESIGN: The effects of XDY on inflammation, autophagy, NACHT-LRR-PYD-containing protein 3 (NLRP3) inflammasome and pyroptosis were assessed in the mice with influenza viral pneumonia. In addition, the mouse macrophage cell line (J774A.1) infected with influenza virus was adopted to decode the in vitro effects of XDY on autophagy, reactive oxygen species (ROS), NLRP3 inflammasome and pyroptosis. We analyzed the XDY-induced autophagy, especially the mitophagy-related ROS clearance, and the subsequent inhibition of ROS/NLRP3 inflammasome/pyroptosis signaling in the infected macrophages by different assays based on quantitative polymerase chain reaction, western blot, flow cytometry, immunofluorescence and enzyme-linked immunosorbent assay. RESULTS: In vivo, XDY could effectively improve the lung inflammatory response in the mice with influenza virus pneumonia, due to an intact autophagy flux-promoting effect and the inhibiting roles on NLRP3 inflammasome and pyroptosis. Notably, in vitro, compared with the infected macrophages treated by the NLRP3 inflammasome agonist (Monosodium urate) or the mitochondrial-targeted antioxidant agent, the XDY-dependent treating could inhibit pyroptosis by negatively regulating the signaling axis of ROS/NLRP3 inflammasome/pyroptosis in the influenza virus-infected macrophages. More interestingly, XDY could promote an intact autophagy flux, inducing mitophagy eliminating the damaged mitochondria to reduce the intracellular ROS accumulation, and thus decrease the oxidative stress in the infected macrophages. Especially, the inhibitor of autophagy inition, 3-Methyladenine, could reverse the inhibitory effect of XDY on ROS-NLRP3 inflammasome-mediated pyroptosis, indicating an XDY-promoted mitophagy-dependent ROS scavenging. CONCLUSION: XDY can promote an intact autophagy flux to eliminate damaged mitochondria, namely mitophagy, which reduces the intracellular ROS accumulation contributing to NLRP3 inflammasome activation, restricting pyroptosis and eventually alleviating the influenza virus-induced inflammatory lesions. The obtained results provide new insights into the mechanism of action of XDY in alleviating influenza virus pneumonia, especially the roles of XDY in anti-oxidation, anti-inflammation and anti-pyroptosis, with potential therapeutic targets for future application in integrative medicine.

Identification of a disulfidptosis-related genes signature for prognostic implication in lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is the most prevalent subtype of non-small cell lung cancer. Additionally, disulfidptosis, a newly discovered type of cell death, has been found to be closely associated with the onset and progression of tumors. METHODS: The study first identified genes related to disulfidptosis through correlation analysis. These genes were then screened using univariate cox regression and LASSO regression, and a prognostic model was constructed through multivariate cox regression. A nomogram was also created to predict the prognosis of LUAD. The model was validated in three independent data sets: GSE72094, GSE31210, and GSE37745. Next, patients were grouped based on their median risk score, and differentially expressed genes between the two groups were analyzed. Enrichment analysis, immune infiltration analysis, and drug sensitivity evaluation were also conducted. RESULTS: In this study, we examined 21 genes related to disulfidptosis and developed a gene signature that was found to be associated with a poorer prognosis in LUAD. Our model was validated using three independent datasets and showed AUC values greater than 0.5 at 1, 3, and 5 years. Enrichment analysis revealed that the disulfidptosis-related genes signature had a multifaceted impact on LUAD, particularly in relation to tumor development, proliferation, and metastasis. Patients in the high-risk group exhibited higher tumor purity and lower stromal score, ESTIMATE score, and Immune score. CONCLUSION: This study constructed a gene signature related to disulfidptosis in lung adenocarcinoma and analyzed its impact on the disease and its association with the tumor microenvironment. The findings of this research provide valuable insights into the understanding of lung adenocarcinoma and could potentially lead to the development of new treatment strategies.

Identification of an immune-related 6-lncRNA panel with a good performance for prognostic prediction in hepatocellular carcinoma by integrated bioinformatics analysis.

Hepatocellular carcinoma (HCC) is one of the most malignant tumors with a poor prognosis. The long non-coding RNA (lncRNA) has been found to have great potential as a prognostic biomarker or therapeutic target for cancer patients. However, the prognostic value and tumor immune infiltration of lncRNAs in HCC has yet to be fully elucidated. To identify prognostic biomarkers of lncRNA in HCC by integrated bioinformatics analysis and explore their functions and relationship with tumor immune infiltration. The prognostic risk assessment model for HCC was constructed by comprehensively using univariate/multivariate Cox regression analysis, Kaplan-Meier survival analysis, and the least absolute shrinkage and selection operator regression analysis. Subsequently, the accuracy, independence, and sensitivity of our model were evaluated, and a nomogram for individual prediction in the clinic was constructed. Tumor immune microenvironment (TIME), immune checkpoints, and human leukocyte antigen alleles were compared in high- and low-risk patients. Finally, the functions of our lncRNA signature were examined using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and gene set enrichment analysis. A 6-lncRNA panel of HCC consisting of RHPN1-AS1, LINC01224, CTD-2510F5.4, RP1-228H13.5, LINC01011, and RP11-324I22.4 was eventually identified, and show good performance in predicting the survivals of patients with HCC and distinguishing the immunomodulation of TIME of high- and low-risk patients. Functional analysis also suggested that this 6-lncRNA panel may play an essential role in promoting tumor progression and immune regulation of TIME. In this study, 6 potential lncRNAs were identified as the prognostic biomarkers in HCC, and the regulatory mechanisms involved in HCC were initially explored.

Compound Kushen Injection inhibits epithelial-mesenchymal transition of gastric carcinoma by regulating VCAM1 induced by the TNF signaling pathway.

BACKGROUND: Gastric carcinoma (GC) treatment needs to be developed rapidly. Compound Kushen Injection (CKI), a formula from traditional Chinese medicine, has been used clinically in combination with chemotherapy to treat GC with satisfactory results. However, the molecular mechanism by which CKI acts to cure GC is still unclear. METHODS: In the present study, in vivo and in vitro experiments were used to assess the efficacy of CKI. Using ceRNA microarray and TMT technologies, the molecular mechanism of CKI was further investigated at the transcriptional and protein levels, and a bioinformatics approach was employed to investigate and functionally validate key CKI targets in GC. RESULTS: When combined with cisplatin (DDP), CKI significantly increased its efficacy in preventing the proliferation and metastasis of GC cells and malignant-looking tumors in mice. High-throughput sequencing data and bioinformatics analysis showed that CKI regulated the TNF signaling pathway, epithelial-mesenchymal transition (EMT), with VCAM1 as a key target. The transcription factors CEBPB, JUN, RELA, NFKB1, the EMT mesenchymal-like cell markers N-cadherin and vimentin, as well as the expression of VCAM1 and its upstream signaling driver TNF, were all downregulated by CKI. In contrast, the expression of the EMT epithelial-like cell marker E-cadherin was upregulated. CONCLUSION: CKI can effectively inhibit GC growth and metastasis, improve body's immunity, and protect normal tissues from damage. The molecular mechanism by which CKI inhibits metastasis of GC is by regulating VCAM1 induced by the TNF signaling pathway to inhibit EMT of GC. Our results provide an important clue to clarify precisely the multi-scale molecular mechanism of CKI in the treatment of GC.

Elucidating the pharmacological effects of Compound Kushen injection on MYC-P15-CCND1 signaling pathway in nasopharyngeal carcinoma - An in vitro study.

ETHNOPHARMACOLOGICAL RELEVANCE: Compound Kushen injection (CKI) is a representative medication of Chinese herbal injection and is often used in the adjuvant treatment of nasopharyngeal carcinoma (NPC), but its antitumor mechanism is poorly understood. AIM OF THE STUDY: To preliminarily elucidate the effects and possible mechanisms of CKI on NPC. METHODS: In this work, we explored the possible molecular mechanisms of CKI against NPC by using network pharmacology and molecular docking. In addition, proteomics was used to explore the localization and quantitative information of protein in NPC C666-1 cells after the intervention of CKI, and enrichment analysis was used to obtain the potential targets and pathways. Finally, the effect and the core targets of CKI in the intervention of NPC were explored in vitro experiments. RESULTS: Network pharmacology analysis identified three active components of CKI and 13 key targets. Molecular docking analysis showed that TNF, PTEN, CCND1, MAPK3, IL6, HIF1A, MYC had high affinity with corresponding components. Then the key pathway, cell cycle and the core targets MYC, CCND1, and P15 related to the key pathway were obtained. The results of in vitro experiments showed that CKI could inhibit the proliferation, migration, and invasion of NPC 5-8F cells and C666-1 cells, induce apoptosis of C666-1 cells, and arrest cell cycle G0/G1 phase. In addition, RT-qPCR and western blot showed that the expression of P15 was up-regulated and E2F4, E2F5, c-Myc, CCND1, and P107 was down-regulated in 5-8F cells and C666-1 cells intervened by CKI. CONCLUSION: The key pathway, cell cycle and the corresponding core targets MYC, CCND1, and P15 were obtained from network pharmacology, molecular docking, and proteomics. CKI could inhibit the proliferation, migration, and invasion of NPC cells, induce apoptosis of C666-1 cells. Especially CKI may arrest cell cycle G0/G1 phase through regulating targets MYC/P15/CCND1 of cell cycle pathway.

Data mining combines bioinformatics discover immunoinfiltration-related gene SERPINE1 as a biomarker for diagnosis and prognosis of stomach adenocarcinoma.

Stomach adenocarcinoma (STAD) is a type of cancer which often at itsadvanced stage apon diagnosis and mortality in clinical practice. Several factors influencethe prognosis of STAD, including the expression and regulation of immune cells in the tumor microenvironment. We here investigated the biomarkers related to the diagnosis and prognosis of gastric cancer, hoping to provide insights for the diagnosis and treatment of gastric cancer in the future. STAD and normal patient RNA sequencing data sets were accessed from the cancer genome atlas (TCGA database). Differential genes were determined and obtained by using the R package DESeq2. The stromal, immune, and ESTIMATE scores are calculated by the ESTIMATE algorithm, followed by the modular genes screening using the R package WGCNA. Subsequently, the intersection between the modular gene and the differential gene was taken and the STRING database was used for PPI network module analysis. The R packages clusterProfiler, enrichplot, and ggplot2 were used for GO and KEGG enrichment analysis. Cox regression analysis was used to screen survival-related genes, and finally, the R package Venn Diagram was used to take the intersection and obtain 7 hub genes. The time-dependent ROC curve and Kaplan-Meier survival curve were used to find the SERPINE1 gene, which plays a critical role in prognosis. Finally, the expression pattern, clinical characteristics, and regulatory mechanism of SERPINE1 were analyzed in STAD. We revealed that the expression of SERPINE1 was significantly increased in the samples from STAD compared with normal samples. Cox regression, time-dependent ROC, and Kaplan-Meier survival analyses demonstrated that SERPINE1 was significantly related to the adverse prognosis of STAD patients. The expression of SERPINE1 increased with the progression of T, N, and M classification of the tumor. In addition, the results of immune infiltration analysis indicated that the immune cells' expression were higher in high SERPINE1 expression group than that in low SERPINE1 expression group, including CD4+ T cells, B cells, CD8+ T cells, macrophages, neutrophils and other immune cells. SERPINE1 was closely related to immune cells in the STAD immune microenvironment and had a synergistic effect with the immune checkpoints PD1 and PD-L1. In conclusion, we proved that SERPINE1 is a promising prognostic and diagnostic biomarker for STAD and a potential target for immunotherapy.

Identification of key pharmacological components and targets for Aidi injection in the treatment of pancreatic cancer by UPLC-MS, network pharmacology, and in vivo experiments.

BACKGROUND: Pancreatic cancer is one of the most lethal cancers worldwide. Aidi injection (ADI) is a representative antitumor medication based on Chinese herbal injection, but its antitumor mechanisms are still poorly understood. MATERIALS AND METHODS: In this work, the subcutaneous xenograft model of human pancreatic cancer cell line Panc-1 was established in nude mice to investigate the anticancer effect of ADI in vivo. We then determined the components of ADI using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS) and explored the possible molecular mechanisms against pancreatic cancer using network pharmacology. RESULTS: In vivo experiments, the volume, weight, and degree of histological abnormalities of implanted tumors were significantly lower in the medium and high concentration ADI injection groups than in the control group. Network pharmacology analysis identified four active components of ADI and seven key targets, TNF, VEGFA, HSP90AA1, MAPK14, CASP3, P53 and JUN. Molecular docking also revealed high affinity between the active components and the target proteins, including Astragaloside IV to P53 and VEGFA, Ginsenoside Rb1 to CASP3 and Formononetin to JUN. CONCLUSION: ADI could reduce the growth rate of tumor tissue and alleviate the structural abnormalities in tumor tissue. ADI is predicted to act on VEGFA, P53, CASP3, and JUN in ADI-mediated treatment of pancreatic cancer.

Berberine ameliorates pulmonary inflammation in mice with influenza viral pneumonia by inhibiting NLRP3 inflammasome activation and gasdermin D-mediated pyroptosis.

Viral pneumonia is a common complication caused by Influenza A virus infection and is characterized by severe pulmonary inflammation. A previous study showed that berberine (BBR) significantly ameliorated the pulmonary inflammation in mice with influenza viral pneumonia but its underlying mechanism is not entirely understood. In this study, we reproduced the mouse model of influenza viral pneumonia through intranasal infection of A/Puerto Rico/8/34 (H1N1), to further investigate the anti-inflammatory mechanism of BBR based on nucleotide-binding oligomerization domain-like receptor protein (NLRP) 3 inflammasome activation and Gasdermin D (GSDMD)-mediated pyroptosis. Consistent with MCC950 (10 mg/kg, a specific NLRP3 inflammasome inhibitor), BBR (10 mg/kg) obviously improved the weight loss and survival rate of infected mice, alleviated their pulmonary inflammation, and suppressed the accumulation of tumor necrosis factor and interleukin (IL)-6 in lungs without obvious inhibition on viral multiplication (hemagglutinin titer and nucleoprotein messenger RNA). Moreover, BBR (10 mg/kg) reduced the expressions of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), and cysteinyl aspartate-specific proteinase (Caspase)1 (Caspase1 precursor [Pro-caspase1] + Caspase1p20 subunit) and the ratio of Caspase1p20 subunit to Caspase1, thus inhibiting the NLRP3 inflammasome activation and resulting in the decreased contents of mature IL-1ß and IL-18 in lungs. The GSDMD expression (GSDMD precursor [Pro-GSDMD] + GSDMD-N terminal [NT]) and the ratio of GSDMD-NT to GSDMD were also declined by BBR (10 mg/kg). These evidence indicate that BBR may ameliorate pulmonary inflammation in mice with influenza viral pneumonia through inhibiting NLRP3 inflammasome activation, as well as depressing GSDMD-mediated pyroptosis via declining GSDMD expression and restraining NLRP3 inflammasome-mediated GSDMD activation.

Single-Cell and Bulk RNA Sequencing Reveal Malignant Epithelial Cell Heterogeneity and Prognosis Signatures in Gastric Carcinoma.

Gastric carcinoma (GC) heterogeneity represents a major barrier to accurate diagnosis and treatment. Here, we established a comprehensive single-cell transcriptional atlas to identify the cellular heterogeneity in malignant epithelial cells of GC using single-cell RNA sequencing (scRNA-seq). A total of 49,994 cells from nine patients with paired primary tumor and normal tissues were analyzed by multiple strategies. This study focused on the malignant epithelial cells, which were divided into three subtypes, including pit mucous cells, chief cells, and gastric and intestinal cells. The trajectory analysis results suggest that the differentiation of the three subtypes could be from the pit mucous cells to the chief cells and then to the gastric and intestinal cells. Lauren's histopathology of GC might originate from various subtypes of malignant epithelial cells. The functional enrichment analysis results show that the three subtypes focused on different biological processes (BP) and pathways related to tumor development. In addition, we generated and validated the prognostic signatures for predicting the OS in GC patients by combining the scRNA-seq and bulk RNA sequencing (bulk RNA-seq) datasets. Overall, our study provides a resource for understanding the heterogeneity of GC that will contribute to accurate diagnosis and prognosis.

An advanced network pharmacology study to explore the novel molecular mechanism of Compound Kushen Injection for treating hepatocellular carcinoma by bioinformatics and experimental verification.

BACKGROUND: Compound Kushen Injection (CKI) is a Chinese patent drug that exerts curative effects in the clinical treatment of hepatocellular carcinoma (HCC). This study aimed to explore the targets and potential pharmacological mechanisms of CKI in the treatment of HCC. METHODS: In this study, network pharmacology was used in combination with molecular biology experiments to predict and verify the molecular mechanism of CKI in the treatment of HCC. The constituents of CKI were identified by UHPLC-MS/MS and literature search. The targets corresponding to these compounds and the targets related to HCC were collected based on public databases. To screen out the potential hub targets of CKI in the treatment of HCC, a compound-HCC target network was constructed. The underlying pharmacological mechanism was explored through the subsequent enrichment analysis. Interactive Gene Expression Profiling Analysis and Kaplan-Meier plotter were used to examine the expression and prognostic value of hub genes. Furthermore, the effects of CKI on HCC were verified through molecular docking simulations and cell experiments in vitro. RESULTS: Network analysis revealed that BCHE, SRD5A2, EPHX2, ADH1C, ADH1A and CDK1 were the key targets of CKI in the treatment of HCC. Among them, only CDK1 was highly expressed in HCC tissues, while the other 5 targets were lowly expressed. Furthermore, the six hub genes were all closely related to the prognosis of HCC patients in survival analysis. Molecular docking revealed that there was an efficient binding potential between the constituents of CKI and BCHE. Experiments in vitro proved that CKI inhibited the proliferation of HepG2 cells and up-regulated SRD5A2 and ADH1A, while down-regulated CDK1 and EPHX2. CONCLUSIONS: This study revealed and verified the targets of CKI on HCC based on network pharmacology and experiments and provided a scientific reference for further mechanism research.

A network pharmacology approach to reveal the pharmacological targets and biological mechanism of compound kushen injection for treating pancreatic cancer based on WGCNA and in vitro experiment validation.

BACKGROUND: Compound kushen injection (CKI), a Chinese patent drug, is widely used in the treatment of various cancers, especially neoplasms of the digestive system. However, the underlying mechanism of CKI in pancreatic cancer (PC) treatment has not been totally elucidated. METHODS: Here, to overcome the limitation of conventional network pharmacology methods with a weak combination with clinical information, this study proposes a network pharmacology approach of integrated bioinformatics that applies a weighted gene co-expression network analysis (WGCNA) to conventional network pharmacology, and then integrates molecular docking technology and biological experiments to verify the results of this network pharmacology analysis. RESULTS: The WGCNA analysis revealed 2 gene modules closely associated with classification, staging and survival status of PC. Further CytoHubba analysis revealed 10 hub genes (NCAPG, BUB1, CDK1, TPX2, DLGAP5, INAVA, MST1R, TMPRSS4, TMEM92 and SFN) associated with the development of PC, and survival analysis found 5 genes (TSPOAP1, ADGRG6, GPR87, FAM111B and MMP28) associated with the prognosis and survival of PC. By integrating these results into the conventional network pharmacology study of CKI treating PC, we found that the mechanism of CKI for PC treatment was related to cell cycle, JAK-STAT, ErbB, PI3K-Akt and mTOR signalling pathways. Finally, we found that CDK1, JAK1, EGFR, MAPK1 and MAPK3 served as core genes regulated by CKI in PC treatment, and were further verified by molecular docking, cell proliferation assay, RT-qPCR and western blot analysis. CONCLUSIONS: Overall, this study suggests that the optimized network pharmacology approach is suitable to explore the molecular mechanism of CKI in the treatment of PC, which provides a reference for further investigating biomarkers for diagnosis and prognosis of PC and even the clinical rational application of CKI.

A New Strategy to Identify ceRNA-Based CCDC144NL-AS1/SERPINE1 Regulatory Axis as a Novel Prognostic Biomarker for Stomach Adenocarcinoma via High Throughput Transcriptome Data Mining and Computational Verification.

Stomach adenocarcinoma (STAD) is one of the most malignant cancers that endanger human health. There is growing evidence that competitive endogenous RNA (ceRNA) regulatory networks play an important role in various human tumors. However, the complexity and behavioral characteristics of the ceRNA network in STAD are still unclear. In this study, we constructed a ceRNA regulatory network to identify the potential prognostic biomarkers associated with STAD. The expression profile of lncRNA, miRNA, and mRNA was downloaded from The Cancer Genome Atlas (TCGA). After performing bioinformatics analysis, the CCDC144NL-AS1/hsa-miR-145-5p/SERPINE1 ceRNA network associated to STAD prognosis of STAD was obtained. The CCDC144NL-AS1/SERPINE1 axis in the ceRNA network was identified by correlation analysis and considered as a clinical prognosis model by Cox regression analysis. In addition, methylation analysis indicated that the abnormal upregulation of CCDC144NL-AS1/SERPINE1 axis might be related to the aberrant methylation of some sites, and immune infiltration analysis suggested that CCDC144NL-AS1/SERPINE1 axis probably influences the alteration of tumor immune microenvironment and the occurrence and development of STAD. In particular, the CCDC144NL-AS1/SERPINE1 axis based on the ceRNA network constructed in the present study might be an important novel factor correlating with the diagnosis and prognosis of STAD.

Berberine suppresses influenza virus-triggered NLRP3 inflammasome activation in macrophages by inducing mitophagy and decreasing mitochondrial ROS.

Berberine (BBR) is an isoquinoline alkaloid extracted from several commonly used Chinese herbs. Our previous studies demonstrated BBR-mediated alleviation of lung injury due to inflammation and decrease in the mortality of mice with influenza viral pneumonia. The recent argument of autophagy against inflammatory responses has aroused wide concerns. This study focuses on the reactive oxygen species-Nod-like receptor protein 3 (ROS-NLRP3) pathway to investigate whether BBR inhibits NLRP3 inflammasome activation by inducing mitophagy. Our results demonstrate that BBR and mitochondrion-targeted superoxide dismutase mimetic (Mito-TEMPO; a specific mitochondrial ROS scavenger) significantly restricted NLRP3 inflammasome activation, increased mitochondrial membrane potential (MMP), and decreased mitochondrial ROS (mtROS) generation in J774A.1 macrophages infected with PR8 influenza virus. These observations suggest that the inhibitory effects of BBR on NLRP3 inflammasome activation were associated with the amelioration of mtROS generation. BBR treatment induced regular mitophagy, as evident from the increase in microtubule-associated protein 1 light chain 3 II, decrease in p62, colocalization of LC3 and mitochondria, and formation of autophagosomes. However, 3-methyladenine, an autophagy inhibitor, reversed the inhibitory effects of BBR on mitochondrial damage and NLRP3 inflammasome activation in influenza virus-infected macrophages, indicating the involvement of mitophagy in mediating the inhibitory effects of BBR on NLRP3 inflammasome activation. Furthermore, the knockdown of Bcl-2/adenovirus E18-19-kDa interacting protein 3 (BNIP3) expression attenuated the effects of BBR on mitophagy induction to some extent, suggesting that the BBR-induced mitophagy may be, at least in part, mediated in a BNIP3-dependent manner. Similar results were obtained in vivo using a mouse model of influenza viral pneumonia that was administered with BBR. Taken together, these findings suggest that restricting NLRP3 inflammasome activation by decreasing ROS generation through mitophagy induction may be crucial for the BBR-mediated alleviation of influenza virus-induced inflammatory lesions.

Dynamic Regulation of Tandem 3' Untranslated Regions in Zebrafish Spleen Cells during Immune Response.

Alternative polyadenylation (APA) has been found to be involved in tumorigenesis, development, and cell differentiation, as well as in the activation of several subsets of immune cells in vitro. Whether APA takes place in immune responses in vivo is largely unknown. We profiled the variation in tandem 3' untranslated regions (UTRs) in pathogen-challenged zebrafish and identified hundreds of APA genes with ∼ 10% being immune response genes. The detected immune response APA genes were enriched in TLR signaling, apoptosis, and JAK-STAT signaling pathways. A greater number of microRNA target sites and AU-rich elements were found in the extended 3' UTRs than in the common 3' UTRs of these APA genes. Further analysis suggested that microRNA and AU-rich element-mediated posttranscriptional regulation plays an important role in modulating the expression of APA genes. These results indicate that APA is extensively involved in immune responses in vivo, and it may be a potential new paradigm for immune regulation.

Evaluation of two statistical methods provides insights into the complex patterns of alternative polyadenylation site switching.

Switching between different alternative polyadenylation (APA) sites plays an important role in the fine tuning of gene expression. New technologies for the execution of 3'-end enriched RNA-seq allow genome-wide detection of the genes that exhibit significant APA site switching between different samples. Here, we show that the independence test gives better results than the linear trend test in detecting APA site-switching events. Further examination suggests that the discrepancy between these two statistical methods arises from complex APA site-switching events that cannot be represented by a simple change of average 3'-UTR length. In theory, the linear trend test is only effective in detecting these simple changes. We classify the switching events into four switching patterns: two simple patterns (3'-UTR shortening and lengthening) and two complex patterns. By comparing the results of the two statistical methods, we show that complex patterns account for 1/4 of all observed switching events that happen between normal and cancerous human breast cell lines. Because simple and complex switching patterns may convey different biological meanings, they merit separate study. We therefore propose to combine both the independence test and the linear trend test in practice. First, the independence test should be used to detect APA site switching; second, the linear trend test should be invoked to identify simple switching events; and third, those complex switching events that pass independence testing but fail linear trend testing can be identified.

Surface IgM on DT40 cells may be a component of the putative receptor complex responsible for the binding of infectious bursal disease virus.

To investigate the host-pathogen interactions between infectious bursal disease virus (IBDV) and target B-lymphocytic cells, a cDNA T7 phage display library from the chicken bursa of Fabricius was constructed and screened for virus binding. Surface immunoglobulin M (sIgM) was isolated as a putative candidate binding site and its interactions with IBDV were further investigated using a chicken bursal lymphoma-derived cell line DT40. The results showed that the λ light chain of sIgM specifically interacted with IBDV in a virulence-independent manner in vitro, and most of the binding of IBDV to DT40 cells was inhibited by sIgM-specific monoclonal antibodies. Further, the infectivity of IBDV in vitro was reduced by sIgM-specific monoclonal antibodies. Our data provided evidence that sIgM may participate as one of the putative membrane binding sites responsible for IBDV infection.

Infectivity and propagation of attenuated infectious bursal disease virus in the chicken B-lymphocyte cell line DT40.

In this paper, the infectivity and propagation of two attenuated infectious bursal disease virus (IBDV) strains in DT40 cells were investigated. The results showed that both of the tested strains, TAD and HN(3), directly infect and proliferate in DT40 cells, requiring no adaptive passages. Unexpectedly, IBDV can be rapidly propagated and continuously harvested at high titers for a long time, accompanied by the rapid growth of host cells and showing no increase in pathogenicity. Our results provide further support to suggest that DT40 cells can be used as an ideal model for studying IBDV pathogenesis. Additionally, the DT40 cell line could also serve as a potential system for commercial IBDV vaccine preparation.