WTAP facilitates progression of endometrial cancer via CAV-1/NF-κB axis

The N⁶-methyladenosine (m⁶A) modification is one of the most prevalent methylations in eukaryotic messenger RNA (mRNA), and it is essential for the development of many important biological processes such as multiple types of tumors. One of the most important enzymes catalyzing generation of m⁶A on mRNA is Wilms' tumor 1-associating protein (WTAP); however, the potential role of WTAP in endometrial cancer (EC) still remains unknown. Here, we investigated WTAP expression level in cancer tissue and paracancerous tissue from an EC patient. Subsequently, WTAP was knocked down by small interfering RNA in EC cell line of Ishikawa and HEC-1A, respectively. Cell proliferation, migration, and invasion were studied. The expression of caveolin-1 (CAV-1) was detected by quantitative polymerase chain reaction (qPCR). The enrichments of m⁶A and METTL3 on CAV-1 were detected using RNA immunoprecipitation-qPCR. The activity of nuclear factor-κB (NF-κB) was studied using Western blot. We observed that WTAP was dramatically upregulated in the cancer tissue, and there was an enhancement in cell proliferation, migration, and invasion and a decrease in EC apoptosis in vivo and in vitro, which indicated higher tumor malignancy and worse survival outcome. After WTAP was knocked down in EC cells, CAV-1 was significantly upregulated and the enrichments of m⁶A and METTL3 at 3′-untranslated region (UTR) region of CAV-1 were decreased. Moreover, the activity of NF-κB signaling pathway was inhibited by its regulator CAV-1. Taken together, we concluded that WTAP could methylate 3′-UTR of CAV-1 and downregulate CAV-1 expression to activate NF-κB signaling pathway in EC, which promoted EC progression.     

Scaffold compound L971 exhibits anti‐inflammatory activities through inhibition of JAK/STAT and NFκB signalling pathways

JAK/STAT and NFκB signalling pathways play essential roles in regulating inflammatory responses, which are important pathogenic factors of various serious immune‐related diseases, and function individually or synergistically. To find prodrugs that can treat inflammation, we performed a preliminary high‐throughput screening of 18 840 small molecular compounds and identified scaffold compound L971 which significantly inhibited JAK/STAT and NFκB driven luciferase activities. L971 could inhibit the constitutive and stimuli‐dependent activation of STAT1, STAT3 and IκBα and could significantly down‐regulate the proinflammatory gene expression in mouse peritoneal macrophages stimulated by LPS. Gene expression profiles upon L971 treatment were determined using high‐throughput RNA sequencing, and significant differentially up‐regulated and down‐regulated genes were identified by DESeq analysis. The bioinformatic studies confirmed the anti‐inflammatory effects of L971. Finally, L971 anti‐inflammatory character was further verified in LPS‐induced sepsis shock mouse model in vivo. Taken together, these data indicated that L971 could down‐regulate both JAK/STAT and NFκB signalling activities and has the potential to treat inflammatory diseases such as sepsis shock.     

Sulfuretin attenuates allergic airway inflammation in mice

Sulfuretin is one of the main flavonoids produced by Rhus verniciflua, which is reported to inhibit the inflammatory response by suppressing the NF-κB pathway. Because NF-κB activation plays a pivotal role in the pathogenesis of allergic airway inflammation, we here examined the effect of sulfuretin on an ovalbumin-induced airway inflammation model in mice. We isolated sulfuretin from R. verniciflua. Sulfuretin was delivered intraperitoneally after the last ovalbumin challenge. Airway hyper-responsiveness, cytokines, mucin, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. A single administration of sulfuretin reduced airway inflammatory cell recruitment and peribronchiolar inflammation and suppressed the production of various cytokines in bronchoalveolar fluid. In addition, sulfuretin suppressed mucin production and prevented the development of airway hyper-responsiveness. The protective effect of sulfuretin was mediated by the inhibition of the NF-κB signaling pathway. Our results suggest that sulfuretin may have therapeutic potential for the treatment of allergic airway inflammation.     

Cysteine-to-Serine Mutants Dramatically Reorder the Active Site of Human ABO(H) Blood Group B Glycosyltransferase without Affecting Activity: Structural Insights into Cooperative Substrate Binding

A common feature in the structures of GT-A-fold-type glycosyltransferases is a mobile polypeptide loop that has been observed to participate in substrate recognition and enclose the active site upon substrate binding. This is the case for the human ABO(H) blood group B glycosyltransferase GTB, where amino acid residues 177-195 display significantly higher levels of disorder in the unliganded state than in the fully liganded state. Structural studies of mutant enzymes GTB/C80S/C196S and GTB/C80S/C196S/C209S at resolutions ranging from 1.93 to 1.40 Å display the opposite trend, where the unliganded structures show nearly complete ordering of the mobile loop residues that is lost upon substrate binding. In the liganded states of the mutant structures, while the UDP moiety of the donor molecule is observed to bind in the expected location, the galactose moiety is observed to bind in a conformation significantly different from that observed for the wild-type chimeric structures. Although this would be expected to impede catalytic turnover, the kinetics of the transfer reaction are largely unaffected. These structures demonstrate that the enzymes bind the donor in a conformation more similar to the dominant solution rotamer and facilitate its gyration into the catalytically competent form. Further, by preventing active-site closure, these structures provide a basis for recently observed cooperativity in substrate binding. Finally, the mutation of C80S introduces a fully occupied UDP binding site at the enzyme dimer interface that is observed to be dependent on the binding of H antigen acceptor analog.     

Metal-directed affinity labeling of zinc(II), cobalt(II) and cadmium(II) horse liver alcohol dehydrogenases

The active site metal in horse liver alcohol dehydrogenase has been studied by metal-directed affinity labeling of the native zinc(II) enzyme and that substituted with cobalt(II) or cadmium(II). Reversible binding of bromoimidazolyl propionic acid to the cobalt enzyme blueshifts the visible absorption band originating from the catalytic cobalt atom at 655 to 630 nm. Binding of imidazole to the cobalt(II) enzyme redshifts the 655 nm band to 667 nm. Addition of bromoimidazolyl propionic acid blueshifts this 667 nm band back to 630 nm. This proves direct binding of the label to the active site metal in competition with imidazole. The affinity of the label for the reversible binding site in the three enzymes follows the order Zn ? Cd ? Co. After reversible complex formation, bromoimidazolyl propionic acid alkylates cysteine-46, one of the protein ligands to the active site metal. The nucleophilic reactivity of this metal-mercaptide bond in each reversible complex follows the order Co ? Zn ? Cd.     

63例慢性乙肝e抗原阴性HBV基因多态性检测结果报告

用地高辛标记引物酶显色法,检测了63例e抗原阴性慢性肝炎HBV基因多态性。结果突变率为53.9%(34/63)。前C/C区1896位突变率最高为49.2%(31/63),1814位38.1%(24/63);BCP区1762位、1764位均为39.7%(25/63),552位突变率为14.3%(9/63)。该检测方法灵敏度高,简便易行。严格控制杂交温度及显色温度是检测操作的关键。     

Role of the adaptor protein CIKS in the activation of the IKK complex

Nuclear factor kappaB (NF-kappaB) plays a pivotal role in numerous cellular processes, including stress response, inflammation, and protection from apoptosis. Therefore, the activity of NF-kappaB needs to be tightly regulated. We have previously identified a novel gene, named CIKS (connection to IkappaB-kinase and SAPK), able to bind the regulatory sub-unit NEMO/IKKgamma and to activate NF-kappaB. Here, we demonstrate that CIKS forms homo-oligomers, interacts with NEMO/IKKgamma, and is recruited to the IKK-complex upon cell stimulation. In addition, we identified the regions of CIKS responsible for these functions. We found that the ability of CIKS to oligomerize, and to be recruited to the IKK-complex is not sufficient to activate the NF-kappaB. In fact, a deletion mutant of CIKS able to oligomerize, to interact with NEMO/IKKgamma, and to be recruited to the IKK-complex does not activate NF-kappaB, suggesting that CIKS needs a second level of regulation to efficiently activate NF-kappaB.     

Alteration of poly(ADP-ribose) glycohydrolase nucleocytoplasmic shuttling characteristics upon cleavage by apoptotic proteases

Poly(ADP-ribosyl)ation is an important post-translational modification which mostly affects nuclear proteins. The major roles of poly(ADP-ribose) synthesis are assigned to DNA damage signalling during base excision repair, apoptosis and excitotoxicity. The transient nature and modulation of poly(ADP-ribose) levels depend mainly on the activity of poly(ADP-ribose) polymerase-1 (PARP-1) and poly(ADP-ribose) glycohydrolase (PARG), the key catabolic enzyme of poly(ADP-ribose). Given the fact that PARG substrate, poly(ADP-ribose), is found almost exclusively in the nucleus and that PARG is mainly localized in the cytoplasm, we wanted to have a closer look at PARG subcellular localization in order to better understand the mechanism by which PARG regulates intracellular poly(ADP-ribose) levels. We examined the subcellular distribution of PARG and of its two enzymatically active C-terminal apoptotic fragments both biochemically and by fluorescence microscopy. Green fluorescent protein (GFP) fusion proteins were constructed for PARG (GFP-PARG), its 74 kDa (GFP-74) and 85 kDa (GFP-85) apoptotic fragments and transiently expressed in COS-7 cells. Localization experiments reveal that all three fusion proteins localize predominantly to the cytoplasm and that a fraction also co-localizes with the Golgi marker FTCD. Moreover, leptomycin B, a drug that specifically inhibits nuclear export signal (NES)-dependent nuclear export, induces a redistribution of GFP-PARG from the cytoplasm to the nucleus and this nuclear accumulation is even more pronounced for the GFP-74 and GFP-85 apoptotic fragments. This observation confirms our hypothesis for the presence of important regions in the PARG sequence that would allow the protein to engage in CRM1-dependent nuclear export. Moreover, the altered nuclear import kinetics found for the apoptotic fragments highlights the importance of PARG N-terminal sequence in modulating PARG nucleocytoplasmic trafficking properties.     

Small molecule glutaminase inhibitors block glutamate release from stimulated microglia

Glutaminase plays a critical role in the generation of glutamate, a key excitatory neurotransmitter in the CNS. Excess glutamate release from activated macrophages and microglia correlates with upregulated glutaminase suggesting a pathogenic role for glutaminase. Both glutaminase siRNA and small molecule inhibitors have been shown to decrease excess glutamate and provide neuroprotection in multiple models of disease, including HIV-associated dementia (HAD), multiple sclerosis and ischemia. Consequently, inhibition of glutaminase could be of interest for treatment of these diseases. Bis-2-(5-phenylacetimido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES) and 6-diazo-5-oxo-l-norleucine (DON), two most commonly used glutaminase inhibitors, are either poorly soluble or non-specific. Recently, several new BPTES analogs with improved physicochemical properties were reported. To evaluate these new inhibitors, we established a cell-based microglial activation assay measuring glutamate release. Microglia-mediated glutamate levels were significantly augmented by tumor necrosis factor (TNF)-α, phorbol 12-myristate 13-acetate (PMA) and Toll-like receptor (TLR) ligands coincident with increased glutaminase activity. While several potent glutaminase inhibitors abrogated the increase in glutamate, a structurally related analog devoid of glutaminase activity was unable to block the increase. In the absence of glutamine, glutamate levels were significantly attenuated. These data suggest that the in vitro microglia assay may be a useful tool in developing glutaminase inhibitors of therapeutic interest.