Coronaviruses encode multifunctional proteins that are critical for viral replication and for blocking the innate immune response to viral infection. One such multifunctional domain is the coronavirus papain-like protease (PLP), which processes the viral replicase polyprotein, has deubiquitinating (DUB) activity, and antagonizes the induction of type I interferon (IFN). Here we characterized the DUB and IFN antagonism activities of the PLP domains of human coronavirus NL63 and severe acute respiratory syndrome (SARS) coronavirus to determine if DUB activity mediates interferon antagonism. We found that NL63 PLP2 deconjugated ubiquitin (Ub) and the Ub-line molecule ISG15 from cellular substrates and processed both lysine-48-and lysine-63-linked polyubiquitin chains. This PLP2 DUB activity was dependent on an intact catalytic cysteine residue. We demonstrated that in contrast to PLP2 DUB activity, PLP2-mediated interferon antagonism did not require enzymatic activity. Furthermore, addition of an inhibitor that blocks coronavirus protease/DUB activity did not abrogate interferon antagonism. These results indicated that a component of coronavirus PLP-mediated interferon antagonism was independent of protease and DUB activity. Overall, these results demonstrate the multifunctional nature of the coronavirus PLP domain as a viral protease, DUB, and IFN antagonist and suggest that these independent activities may provide multiple targets for antiviral therapies.The front-line defense of a host cell against virus infection is the innate immune system, which utilizes multiple membrane and cytoplasmic sensors, such as toll-like receptors (TLRs) and RNA helicases, to detect pathogen-associated molecular patterns like viral RNA (3,9,31,47,54). Activation of these sensors by viral RNA intermediates sets off a cascade of signaling events that ultimately turn on transcription factors, such as NF-B, ATF2/c-Jun, IRF-7, and IRF-3. These activated transcription factors translocate to the nucleus and upregulate transcription of interferon (IFN) mRNAs. The translation and subsequent secretion of IFNs activates cells to upregulate interferon-stimulated genes (ISGs) to establish an antiviral state hostile to viral replication. Of importance for this study, many of the signaling events that link the sensors to the transcription factors are mediated by the activities of kinases and ubiquitinating enzymes that modify and activate critical intermediates in the cascade (7,8,20,25). For example, signaling from RIG-I can proceed through MAVS/TRAF3/TANK to TBKI and inducible IB kinase (IKKi), which ultimately phosphorylate IRF-3. Recent studies indicate that both TRAF3 and TANK are modified by lysine-63-linked polyubiquitination and can be inactivated by DUBA, a cellular deubiquitinating (DUB) enzyme (28). Thus, ubiquitinating enzymes and DUBs are critical players in modulating the innate immune response.For positive-strand RNA viruses that replicate in the cytoplasm of the cell using double-stranded RNA intermediates, the cytoplasmic innate i...
Purpose – In response to food scares related to high levels of agro-chemical residues sometimes found on foods, consumers in China increasingly demand for organic foods. As little is known on consumer perceptions and attitudes toward organic food products, the purpose of this paper is to gain insight into the purchase of organic food products by consumers and to explore the main factors driving this process. Design/methodology/approach – Mixed (quantitative and qualitative) market survey approaches were used to provide a potentially deeper insight into consumer’s perspective and could help get a better picture of the complex factors involved. Findings – The main trigger for purchasing organic food products is that consumers expect them to be healthier and safer. The respondents who have bought organic food products tend to have a higher education level and disposable incomes, be families with children and be older than those who have not bought them. The main barriers to increasing the market share of organic food products are the consumers’ lack of knowledge, the relatively high price premium and the lack of availability of organic food products. Informing consumers about unique characteristics of organic production methods, the decline in the prices of and increasing the availability of organic food products to its customers might be a promising strategy to develop the market for organic food products. Originality/value – This paper provides a unique insight into buying behavior and attitudes of organic consumers in China. The results of the research could provide information for the organic food industry to expand its market and improve its profitability and reliability.
Axicabtagene ciloleucel (Axi-cel) is a CD-19 Chimeric Antigen Receptor T cell therapy approved for the treatment of relapsed/refractory diffuse large B cell lymphoma. We treated ten patients with DLBCL post-FDA approval in an inner-city tertiary center in the Bronx. Eight patients (80%) had received ≥ 3 lines of therapy, six patients had received prior radiation, and seven had recurrent disease after prior autologous hematopoietic stem cell transplant (AHCT). Our cohort included one patient with HIV, two patients with hepatitis B, and two patients with CNS involvement of lymphoma. Axi-cel treatment led to significant responses with 8/10 patients achieving a complete remission at 3 months, including both patients with prior CNS involvement. The treatment was generally well tolerated with 20% of patients experiencing grade ≥ 2 CRS. One patient each with HIV and hepatitis B responded without significant toxicities. In conclusion, Axi-cel led to significant efficacy with manageable toxicity in DLBCL in a real-world setting.
Abstract. We use the discriminant to determine the automorphism groups of some noncommutative algebras, and we prove that a family of noncommutative algebras has tractable automorphism groups.
Halogen bonding, a specific intermolecular noncovalent interaction, plays crucial roles in fields as diverse as molecular recognition, crystal engineering, and biological systems. This paper presents an ab initio investigation of a series of dimeric complexes formed between bromobenzene and several electron donors. Such small model systems are selected to mimic halogen bonding interactions found within crystal structures as well as within biological molecules. In all cases, the intermolecular distances are shown to be equal to or below sums of van der Waals radii of the atoms involved. Halogen bonding energies, calculated at the MP2/aug-cc-pVDZ level, span over a wide range, from -1.52 to -15.53 kcal/mol. The interactions become comparable to, or even prevail over, classical hydrogen bonding. For charge-assisted halogen bonds, calculations have shown that the strength decreases in the order OH- > F- > HCO2- > Cl- > Br-, while for neutral systems, their relative strengths attenuate in the order H2CS > H2CO > NH3 > H2S > H2O. These results agree with those of the quantum theory of atoms in molecules (QTAIM) since bond critical points (BCPs) are identified for these halogen bonds. The QTAIM analysis also suggests that strong halogen bonds are more covalent in nature, while weak ones are mostly electrostatic interactions. The electron densities at the BCPs are recommended as a good measure of the halogen bond strength. Finally, natural bond orbital (NBO) analysis has been applied to gain more insights into the origin of halogen bonding interactions.
Human coronavirus NL63 (HCoV-NL63), a common human respiratory pathogen, is associated with both upper and lower respiratory tract disease in children and adults. Currently, no antiviral drugs are available to treat CoV infections; thus, potential drug targets need to be identified and characterized. Here, we identify HCoV-NL63 replicase gene products and characterize two viral papain-like proteases (PLPs), PLP1 and PLP2, which process the viral replicase polyprotein. We generated polyclonal antisera directed against two of the predicted replicase nonstructural proteins (nsp3 and nsp4) and detected replicase proteins from HCoV-NL63-infected LLC-MK2 cells by immunofluorescence, immunoprecipitation, and Western blot assays. We found that HCoV-NL63 replicase products can be detected at 24 h postinfection and that these proteins accumulate in perinuclear sites, consistent with membrane-associated replication complexes. To determine which viral proteases are responsible for processing these products, we generated constructs representing the amino-terminal end of the HCoV-NL63 replicase gene and established protease cis-cleavage assays. We found that PLP1 processes cleavage site 1 to release nsp1, whereas PLP2 is responsible for processing both cleavage sites 2 and 3 to release nsp2 and nsp3. We expressed and purified PLP2 and used a peptide-based assay to identify the cleavage sites recognized by this enzyme. Furthermore, by using K48-linked hexa-ubiquitin substrate and ubiquitin-vinylsulfone inhibitor specific for deubiquitinating enzymes (DUBs), we confirmed that, like severe acute respiratory syndrome (SARS) CoV PLpro, HCoV-NL63 PLP2 has DUB activity. The identification of the replicase products and characterization of HCoV-NL63 PLP DUB activity will facilitate comparative studies of CoV proteases and aid in the development of novel antiviral reagents directed against human pathogens such as HCoV-NL63 and SARS-CoV.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.