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Your search keyword '"Yu, Xilan"' showing total 38 results
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38 results on '"Yu, Xilan"'

35. The expanding roles of endoplasmic reticulum stress in virus replication and pathogenesis.

Author

Li, Shanshan, Kong, Lingbao, and Yu, Xilan

Subjects
ENDOPLASMIC reticulum, VIRAL replication, DEVELOPMENTAL biology, HOMEOSTASIS, CELLULAR signal transduction, ANTIVIRAL agents, DRUG development
Abstract

The endoplasmic reticulum (ER) is a cellular membrane organelle that plays important roles in virus replication and maturation. Accumulating evidence indicates that virus infection often disturbs ER homeostasis and leads to ER stress, which is associated with a variety of prevalent diseases. To cope with the deleterious effects of virus-induced ER stress, cells activate critical signaling pathways including the unfolded protein response (UPR) and intrinsic mitochondrial apoptosis, which have complex effects on virus replication and pathogenesis. In this review, we present a comprehensive summary of recent research in this field, which revealed that about 36 viruses trigger ER stress and differentially activate ER stress-related signaling pathways. We also highlight the strategies evolved by viruses to modulate ER stress-related signaling networks including immune responses in order to ensure their survival and pathogenesis. Together, the knowledge gained from this field will shed light on unveiling the mechanisms of virus replication and pathogenesis and provide insight for future research as well as antiviral development. [ABSTRACT FROM AUTHOR]

Published
2015
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36. Transcriptional Analysis of the Global Regulatory Networks Active in Pseudomonas syringaeduring Leaf Colonization

Author

Yu, Xilan, Lund, Steven P., Greenwald, Jessica W., Records, Angela H., Scott, Russell A., Nettleton, Dan, Lindow, Steven E., Gross, Dennis C., and Beattie, Gwyn A.

Abstract

ABSTRACTThe plant pathogen Pseudomonas syringaepv. syringae B728a grows and survives on leaf surfaces and in the leaf apoplast of its host, bean (Phaseolus vulgaris). To understand the contribution of distinct regulators to B728a fitness and pathogenicity, we performed a transcriptome analysis of strain B728a and nine regulatory mutants recovered from the surfaces and interior of leaves and exposed to environmental stresses in culture. The quorum-sensing regulators AhlR and AefR influenced few genes in plantaor in vitro. In contrast, GacS and a downstream regulator, SalA, formed a large regulatory network that included a branch that regulated diverse traits and was independent of plant-specific environmental signals and a plant signal-dependent branch that positively regulated secondary metabolite genes and negatively regulated the type III secretion system. SalA functioned as a central regulator of iron status based on its reciprocal regulation of pyoverdine and achromobactin genes and also sulfur uptake, suggesting a role in the iron-sulfur balance. RetS functioned almost exclusively to repress secondary metabolite genes when the cells were not on leaves. Among the sigma factors examined, AlgU influenced many more genes than RpoS, and most AlgU-regulated genes depended on RpoN. RpoN differentially impacted many AlgU- and GacS-activated genes in cells recovered from apoplastic versus epiphytic sites, suggesting differences in environmental signals or bacterial stress status in these two habitats. Collectively, our findings illustrate a central role for GacS, SalA, RpoN, and AlgU in global regulation in B728a in plantaand a high level of plasticity in these regulators’ responses to distinct environmental signals.IMPORTANCELeaves harbor abundant microorganisms, all of which must withstand challenges such as active plant defenses and a highly dynamic environment. Some of these microbes can influence plant health. Despite knowledge of individual regulators that affect the fitness or pathogenicity of foliar pathogens, our understanding of the relative importance of various global regulators to leaf colonization is limited. Pseudomonas syringaestrain B728a is a plant pathogen and a good colonist of both the surfaces and interior of leaves. This study used global transcript profiles of strain B728a to investigate the complex regulatory network of putative quorum-sensing regulators, two-component regulators, and sigma factors in cells colonizing the leaf surface and leaf interior under stressful in vitroconditions. The results highlighted the value of evaluating these networks in plantadue to the impact of leaf-specific environmental signals and suggested signal differences that may enable cells to differentiate surface versus interior leaf habitats.

Published
2014
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37. Anti-tumor activity of metformin: from metabolic and epigenetic perspectives.

Author

Yu X, Mao W, Zhai Y, Tong C, Liu M, Ma L, Yu X, and Li S

Subjects
Apoptosis drug effects, Humans, Neoplasms immunology, Antineoplastic Agents pharmacology, Epigenesis, Genetic drug effects, Metformin pharmacology, Neoplasms metabolism
Abstract

Metformin has been used to treat type 2 diabetes for over 50 years. Epidemiological, preclinical and clinical studies suggest that metformin treatment reduces cancer incidence in diabetes patients. Due to its potential as an anti-cancer agent and its low cost, metformin has gained intense research interest. Its traditional anti-cancer mechanisms involve both indirect and direct insulin-dependent pathways. Here, we discussed the anti-tumor mechanism of metformin from the aspects of cell metabolism and epigenetic modifications. The effects of metformin on anti-cancer immunity and apoptosis were also described. Understanding these mechanisms will shed lights on application of metformin in clinical trials and development of anti-cancer therapy.

Published
2017
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38. Hepatitis C virus NS4B induces unfolded protein response and endoplasmic reticulum overload response-dependent NF-kappaB activation.

Author

Li S, Ye L, Yu X, Xu B, Li K, Zhu X, Liu H, Wu X, and Kong L

Subjects
Activating Transcription Factor 6 metabolism, Calcium metabolism, Cell Line, Cell Nucleus chemistry, Cytoplasm chemistry, DNA-Binding Proteins metabolism, Humans, I-kappa B Proteins metabolism, NF-KappaB Inhibitor alpha, Reactive Oxygen Species metabolism, Regulatory Factor X Transcription Factors, Transcription Factors metabolism, X-Box Binding Protein 1, Endoplasmic Reticulum metabolism, Hepacivirus physiology, Hepatocytes virology, NF-kappa B biosynthesis, Viral Nonstructural Proteins metabolism
Abstract

Hepatitis C virus nonstructural protein 4B (NS4B) is an endoplasmic reticulum (ER) membrane associated protein and a potent causative factor of ER stress. Here we reported that unfolded protein response (UPR) can be activated by HCV NS4B through inducing both XBP1 mRNA splicing and ATF6 cleavage in human hepatic cells. Flow cytometric analysis revealed that HCV NS4B stimulates the production of reactive oxygen species (ROS) by perturbing intracellular Ca(2+) homeostasis. Luciferase assay showed that HCV NS4B also activates the multifunctional transcription factor, NF-kappaB, in a dose-dependent manner through Ca(2+) signaling and ROS. Further immunoblot analysis showed that HCV NS4B promotes NF-kappaB translocation into the nucleus via protein-tyrosine kinase (PTK) mediated phosphorylation and subsequent degradation of IkappaBalpha. These studies provide an important insight into the implication of NS4B in HCV life cycle and HCV-associated liver disease by affecting host intracellular signal transduction pathways.

Published
2009
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