A Novel Vibriophage vB＿VcaS＿HC Containing Lysogeny-Related Gene Has Strong Lytic Ability against Pathogenic Bacteria

To avoid the negative effects of antibiotics, using phage to prevent animal disease becomes a promising method in aquaculture. Here, a lytic phage provisionally named v B＿VcaS＿HC that can infect the pathogen(i.e., Vibrio campbellii 18)of prawn was isolated. The phage has an isometric head and a non-contractile tail. During phage infection, the induced host mortality in 5.5 h reached ca. 96%, with a latent period of 1.5 h and a burst size of 172 PFU/cell. It has an 81,566 bp circular dsDNA genome containing 121 open reading frames(ORFs), and ca. 71% of the ORFs are functionally unknown.Comparative genomic and phylogenetic analysis revealed that it is a novel phage belonging to Delepquintavirus,Siphoviridae, Caudovirales. In the phage genome, besides the ordinary genes related to structure assembly and DNA metabolism, there are 10 auxiliary metabolic genes. For the first time, the pyruvate phosphate dikinase(PPDK) gene was found in phages whose product is a key rate-limiting enzyme involving Embden-Meyerhof-Parnas(EMP) reaction.Interestingly, although the phage has a strong bactericidal activity and contains a potential lysogeny related gene, i.e., the recombinase(RecA) gene, we did not find the phage turned into a lysogenic state. Meanwhile, the phage genome does not contain any bacterial virulence gene or antimicrobial resistance gene. This study represents the first comprehensive characterization of a lytic V. campbellii phage and indicates that it is a promising candidate for the treatment of V.campbellii infections.     

Advanced glycation end products of bovine serum albumin affect the cell growth of human umbilical vein endothelial cells via modulation of MEG3/miR-93/p21 pathway

Advanced glycation end products of BSA (AGE-BSA) contribute to the pathogenesis of diabetic vascular diseases.However,the roles and underlying mechanisms of AGE-BSA in diabetic vascular diseases remain largely unclear.Long non-coding RNAs (lncRNAs) are widely identified and known as gene regulators.However,the roles of lncRNAs in diabetic vascular disease are still vague.In this study,we sought to investigate the contributions of lncRNAs in human umbilical vein endothelial cells (HUVECs) treated with AGE-BSA.We first demonstrated that AGE-BSA reduced the cell viability and inhibited the cell proliferation of HUVECs.Then,we found that lncRNA MEG3 was up-regulated in HUVECs treated with AGE-BSA.Furthermore,inhibition of MEG3 restored the AGE-BSA-induced repression of cell viability and proliferation.In addition,our results revealed that MEG3 played its role via modulation of miR-93 expression in HUVECs treated with AGE-BSA.Furthermore,we illustrated that miR-93 played its role via regulation of p21 in HUVECs treated with AGE-BSA.Ultimately,our study displayed that AGE-BSA exerted its function via modulation of MEG3/miR-93/p21 pathway in HUVECs.Thus,for the first time,we identified the MEG3/miR-93/p21 axis in HUVECs treated with AGE-BSA,which might be a novel regulatory network in diabetic vascular cells,and possess the potential therapeutic value for diabetes mellitus.     

The role of the N-methyl-d-aspartate receptor in the proliferation of adult hippocampal neural stem and precursor cells

New neurons are continuously generated from resident pools of neural stem and precursor cells(NSPCs)in the adult brain.There are multiple pathways through which adult neurogenesis is regulated,and here we review the role of the N-methyl-D-aspartate receptor(NMDAR)in regulating the proliferation of NSPCs in the adult hippocampus.Hippocampal-dependent learning tasks,enriched environments,running,and activity-dependent synaptic plasticity,all potently up-regulate hippocampal NSPC proliferation.We first consider the requirement of the NMDAR in activity-dependent synaptic plasticity,and the role the induction of synaptic plasticity has in regulating NSPCs and newborn neurons.We address how specific NMDAR agonists and antagonists modulate proliferation,both in vivo and in vitro,and then review the evidence supporting the hypothesis that NMDARs are present on NSPCs.We believe it is important to understand the mechanisms underlying the activation of adult neurogenesis,given the potential that endogenous stem cell populations have for repopulating the hippocampus with functional new neurons.In conditions such as age-related memory decline,neurodegeneration and psychiatric disease,mature neurons are lost or become defective;as such,stimulating adult neurogenesis may provide a therapeutic strategy to overcome these conditions.     

m6A mRNA modification potentiates Th17 functions to inflame autoimmunity

N⁶-methyladenosine (m⁶A),the most common and abundant epigenetic RNA modification,governs m RNA metabolism to determine cell differentiation,proliferation and response to stimulation.m⁶A methyltransferase METTL3 has been reported to control T cell homeostasis and sustain the suppressive function of regulatory T cells (Tregs).However,the role of m⁶A methyltransferase in other subtypes of T cells remains unknown.T helper cells 17 (Th17) play a pivotal ro...     

TRIM29 prevents hepatocellular carcinoma progression by inhibiting Wnt/β-catenin signaling pathway

TRIM29 plays an important role in many neoplasms.In this study,we aimed to elucidate its role in hepatocellular carcinoma (HCC) and explore the corresponding potential mechanism.The expression level of TRIM29 in HCC samples and hepatoma cell lines was detected.We found that TRIM29 was down-regulated in clinical HCC samples and cultured hepatoma cell lines by western blot analysis and quantitative polymerase chain reaction.In addition,we demonstrated that higher TRIM29 expression was associated with higher differentiation grade of HCC.To explore the effect of TRIM29 on hepatoma cells and its possible mechanisms,TRIM29-knockdown and overexpression cell models were constructed.The results showed that the depletion of TRIM29 promoted liver cancer cell proliferation,clone formation,migration and invasion in vitro probably through the Wnt/β-catenin signaling pathway.This study revealed the inhibitory roles of TRIM29 in HCC and the possible mechanisms.     

The roles of endomembrane trafficking in plant abiotic stress responses

Endomembrane trafficking is a fundamental cellular process in all eukaryotic cells and its regulatory mechanisms have been extensively studied.In plants,the endomembrane trafficking system needs to be constantly adjusted to adapt to the ever-changing environment.Evidence has accumulated supporting the idea that endomembrane trafficking is tightly linked to stress signaling pathways to meet the demands of rapid changes in cellular processes and to ensure the correct delivery of stress-related cargo molecules.However,the underlying mechanisms remain unknown.In this review,we summarize the recent findings on the functional roles of both secretory trafficking and endocytic trafficking in different types of abiotic stresses.We also highlight and discuss the unique properties of specific regulatory molecules beyond their conventional functions in endosomal trafficking during plant growth under stress conditions.     

Tumor necrosis factor a accelerates Hep-2 cells proliferation by suppressing TRPP2 expression

TRPP2, a Ca~(2+)-permeable non-selective cation channel, has been shown to negatively regulate cell cycle, but the mechanism underlying this regulation is unknown. Tumor necrosis factor a(TNF-α) is a proinflammatory cytokine extensively involved in immune system regulation, cell proliferation and cell survival. However, the effects and mechanisms for the role of TNF-αin laryngeal cancer remain unclear. Here, we demonstrated using western blot analyses and intracellular Ca~(2+) concentration measurements that TNF-α treatment suppressed both TRPP2 expression and ATP-induced Ca~(2+) release in a laryngeal cancer cell line(Hep-2). Knockdown of TRPP2 by a specific siRNA significantly decreased ATP-induced Ca~(2+) release and abolished the effect of TNF-α on the ATP-induced Ca~(2+) release. TNF-α treatment also enhanced Hep-2 cell proliferation and growth, as determined using cell counting and flow cytometry cell cycle assays. Moreover, TNF-α treatment down-regulated phosphorylated protein kinase R-like endoplasmic reticulum kinase(p-PERK) and phosphorylated eukaryotic translation initiation factor(p-eIF2α)expression levels, without affecting PERK and eIF2 a expression levels in Hep-2 cells. We concluded that suppressing TRPP2 expression and TRPP2-mediated Ca~(2+) signaling may be one mechanism underlying TNF-α-enhanced Hep-2 cell proliferation.These results offer new insights into the mechanisms of TNF-α-mediated laryngeal cancer cell proliferation, and provide evidences showing a potential role of TNF-α in the development of laryngeal cancer.     

mTOR regulates TLR-induced c-fos and Th1 responses to HBV and HCV vaccines

Although IL-12 plays a critical role in priming Th1 and cytotoxic T lymphocyte(CTL) responses, Toll-like receptor(TLR) signaling only induces low amounts of IL-12 in dendritic cells and macrophages, implying the existence of stringent regulatory mechanisms. In this study, we sought to uncover the mechanisms underlying TLR-induced IL-12 expression and the Th1 response. By systemic screening, we identified a number of protein kinases involved in the regulation of TLRinduced IL-12 expression. In particular, PI3 K, ERK, and m TOR play critical roles in the TLR-induced Th1 response by regulating IL-12 and IL-10 production in innate immune cells. Moreover, we identified c-fos as a key molecule that mediates m TOR-regulated IL-12 and IL-10 expression in TLR signaling. Mechanistically, m TOR plays a crucial role in c-fos expression, thereby modulating NFκB binding to promoters of IL-12 and IL-10. By controlling the expression of a special innate gene program, m TOR can specifically regulate the TLR-induced T cell response in vivo. Furthermore, blockade of m TOR by rapamycin efficiently boosted TLR-induced antigen-specific T and B cell responses to HBV and HCV vaccines. Taken together, these results reveal a novel mechanism through which m TOR regulates TLR-induced IL-12 and IL-10 production, contributing new insights for strategies to improve vaccine efficacy.     

Regulation of EGF-induced ERK/MAPK activation and EGFR internalization by G protein-coupled receptor kinase 2

G protein-coupled receptor kinases （GRKs） mediate agonist-induced phosphorylation and desensitization of various G protein-coupled receptors （GPCRs）. We investigate the role of GRK2 on epidermal growth factor （EGF） receptor signaling, including EGF-induced extracellular signal-regulated kinase and mitogen-activated protein kinase （ERK/MAPK） activation and EGFR internalization. Immunoprecipitation and immunofluorescence experiments show that EGF stimulates GRK2 binding to EGFR complex and GRK2 translocating from cytoplasm to the plasma membrane in human embryonic kidney 293 cells. Western blotting assay shows that EGF-induced ERK/MAPK phosphorylation increases 1.9-fold, 1.1-fold and 1.5fold （P〈0.05） at time point 30, 60 and 120 min, respectively when the cells were transfected with GRK2,suggesting the regulatory role of GRK2 on EGF-induced ERK/MAPK activation. Flow cytometry experiments show that GRK2 overexpression has no effect on EGF-induced EGFR internalization, however, it increases agonist-induced G protein-coupled δ5 opioid receptor internalization by approximately 40% （P〈0.01）. Overall,these data suggest that GRK2 has a regulatory role in EGF-induced ERK/MAPK activation, and that the mechanisms underlying the modulatory role of GRK2 in EGFR and GPCR signaling pathways are somewhat different at least in receptor internalization.     

The hidden switches undertying RORα-mediated circuits that critically regulate uncontrolled cell proliferation

Prostaglandin E2 （PGE2） is known to have a key role in the development of colorectal cancer, but previous experiments showed its contrasting （i.e. tumor-promoting or tu mor-suppressive） roles depending on experimental conditions. To elucidate the mechanisms underlying such contrasting roles of PG E2 in tumorigenesis, we investigated all the previous experiments and found a new signal transduction pathway mediated by retinoic acid receptor-related orphan receptor （ROR）α, in which PGE2/PKCα-dependent phosphorylation of RORα attenuates Wnt target gene expression in colon cancer ceils. From mathematical simulations combined with biochemical experimentation, we revealed that RORα induces a biphasic response of Wnt target genes to PGE2 stimulation through a regulatory switch formed by an incoherent feedforward loop, which provides a mechanistic explanation on the contrasting roles of PGE2 observed in previous experiments. More interestingly, we found that RORα constitutes another regulatory switch formed by coupled positive and negative feedback loops, which regulates the hysteretic response of Wnt signaling and eventually converts a proliferative cellular state into an anti-proliferative state in a very delicate way. Our results indicate that RORα is the key regulator at the center of these hidden switches that critically regulate cancer celt proliferation and thereby being a promising anti-cancer therapeutic target.     

Genomic instability as a major mechanism for acquired resistance to EGFR tyrosine kinase inhibitors in cancer

The mutation-mediated overexpression of epidermal growth factor receptor tyrosine kinase(EGFR TK)and its activation play an important role in the cellular proliferation and epithelial tumorigenesis.A series of inhibitors targeting the intracellular tyrosine kinase(TK)domain of EGFR have been developed and applied to clinical practice.Although these inhibitors safely and effectively restrain tumor cell proliferation and prolong survival in some patients,acquired resistance ultimately arises.DNA mutations contribute to druginduced cancer-cell resistance.     

The revolution of the biology of the genome

Sequence data of entire eukaryotic genomes and their detailed comparison have provided new evidence on genome evolution. The major mechanisms involved in the increase of genome sizes are polyploidization and gene duplication.Subsequent gene silencing or mutations, preferentially in regulatory sequences of genes, modify the genome and permit the development of genes with new properties. Mechanisms such as lateral gene transfer, exon shuffling or the creation of new genes by transposition contribute to the evolution of a genome, but remain of relatively restricted relevance.Mechanisms to decrease genome sizes and, in particular, to remove specific DNA sequences, such as blocks of satellite DNAs, appear to involve the action of RNA interference (RNAi). RNAi mechanisms have been proven to be involved in chromatin packaging related with gene inactivation as well as in DNA excision during the macronucleus development in ciliates.