Title: Design, Synthesis and Biological Evaluation of New 3,4-Dihydro-2(1H)-Quinolinone-Dithiocarbamate Derivatives as Multifunctional Agents for the Treatment of Alzheimer's Disease Guo J, Xu A, Cheng M, Wan Y, Wang R, Fang Y, Jin Y, Xie SS, Liu J Ref: Drug Des Devel Ther, 16:1495, 2022 : PubMed
BACKGROUND: Alzheimer's disease (AD) belongs to neurodegenerative disease, and the increasing number of AD patients has placed a heavy burden on society, which needs to be addressed urgently. ChEs/MAOs dual-target inhibitor has potential to treat AD according to reports. PURPOSE: To obtain effective multi-targeted agents for the treatment of AD, a novel series of hybrid compounds were designed and synthesized by fusing the pharmacophoric features of 3,4-dihydro-2 (1H)-quinolinone and dithiocarbamate. METHODS: All compounds were evaluated for their inhibitory abilities of ChEs and MAOs. Then, further biological activities of the most promising candidate 3e were determined, including the ability to cross the blood-brain barrier (BBB), kinetics and molecular model analysis, cytotoxicity in vitro and acute toxicity studies in vivo. RESULTS: Most compounds showed potent and clear inhibition to AChE and MAOs. Among them, compound 3e was considered to be the most effective and balanced inhibitor to both AChE and MAOs (IC(50)=0.28 microM to eeAChE; IC(50)=0.34 microM to hAChE; IC(50)=2.81 microM to hMAO-B; IC(50)=0.91 microM to hMAO-A). In addition, 3e showed mixed inhibition of hAChE and competitive inhibition of hMAO-B in the enzyme kinetic studies. Further studies indicated that 3e could penetrate the BBB and showed no toxicity on PC12 cells and HT-22 cells when the concentration of 3e was lower than 12.5 microM. More importantly, 3e lacked acute toxicity in mice even at high dose (2500 mg/kg, P.O.). CONCLUSION: This work indicated that compound 3e with a six-carbon atom linker and a piperidine moiety at terminal position was a promising candidate and was worthy of further study.
Title: Identification and Comparative Genomic Analysis of Type VI Secretion Systems and Effectors in Klebsiella pneumoniae Li W, Liu X, Tsui W, Xu A, Li D, Zhang X, Li P, Bian X, Zhang J Ref: Front Microbiol, 13:853744, 2022 : PubMed
Klebsiella pneumoniae is a nosocomial opportunistic pathogen that can cause pneumonia, liver abscesses, and infections of the bloodstream. The resistance and pathogenicity of K. pneumoniae pose major challenges to clinical practice. However, the ecology and pathogenic mechanisms of K. pneumoniae have not been fully elucidated. Among these mechanisms, the secretion systems encoded by strains of the bacteria confer adaptive advantages depending on the niche occupied. The type VI secretion system (T6SS) is a multi-protein complex that delivers effector proteins to the extracellular environment or directly to eukaryotic or prokaryotic cells. T6SSs are widely distributed in Gram-negative bacteria and play an important role in bacterial virulence and the interactions between bacteria and other microorganisms or the environment. This study aimed to enhance the understanding of the characteristics of T6SSs in K. pneumoniae through an in-depth comparative genomic analysis of the T6SS in 241 sequenced strains of K. pneumoniae. We identified the T6SS loci, the synteny of the loci in different species, as well as the effectors and core T6SS-related genes in K. pneumoniae. The presence of a T6SS was a common occurrence in K. pneumoniae, and two T6SS clusters are the most prevalent. The variable region downstream of the gene vgrG usually encodes effector proteins. Conserved domain analysis indicated that the identified putative effectors in K. pneumoniae had the functions of lipase, ribonuclease, deoxyribonuclease, and polysaccharide hydrolase. However, some effectors did not contain predicted functional domains, and their specific functions have yet to be elucidated. This in silico study represents a detailed analysis of T6SS-associated genes in K. pneumoniae and provides a foundation for future studies on the mechanism(s) of T6SSs, especially effectors, which may generate new insights into pathogenicity and lead to the identification of proteins with novel antimicrobial properties.
Title: Application of a novel fluorogenic polyurethane analogue probe in polyester-degrading microorganisms screening by microfluidic droplet Xu A, Liu J, Cao S, Xu B, Guo C, Yu Z, Chen X, Zhou J, Dong W, Jiang M Ref: Microb Biotechnol, :, 2022 : PubMed
Application of polyester-degrading microorganisms or enzymes should be considered as an eco-friendly alternative to chemical recycling due to the huge plastic waste disposal nowadays. However, current impranil DLN-based screening of polyester-degrading microorganisms is time-consuming, labour-intensive and unable to distinguish polyesterases from other protease- or amidase-like enzymes. Herein, we present an approach that combined a novel synthetic fluorescent polyurethane analogue probe (FPAP), along with the droplet-based microfluidics to screen polyurethane-degrading microorganisms through fluorescence-activated droplet sorting (FADS) pipeline. The fluorescent probe FPAP exhibited a fluorescence enhancement effect once hydrolysed by polyesterases, along with a strong specificity in discriminating polyesterases from other non-active enzymes. Application of FPAP in a microfluidic droplet system demonstrated that this probe exhibited high sensitivity and efficiency in selecting positive droplets containing leaf-branch compost cutinase (LCC) enzymes. This novel fluorogenic probe, FPAP, combined with the droplet microfluidic system has the potential to be used in the exploitation of novel PUR-biocatalysts for biotechnological and environmental applications.
Title: Tacrine-hydroxamate derivatives as multitarget-directed ligands for the treatment of Alzheimer's disease: Design, synthesis, and biological evaluation Xu A, He F, Zhang X, Li X, Ran Y, Wei C, James Chou C, Zhang R, Wu J Ref: Bioorg Chem, 98:103721, 2020 : PubMed
In order to develop multitarget-directed ligands as potential treatments for Alzheimer's disease, twenty-eight new tacrine-hydroxamate derivatives were designed, synthesized, and biologically evaluated. As expected, most of the compounds exhibited inhibitory activities against cholinesterases (ChEs) and histone deacetylase (HDACs). Among the tested compounds, A10 showed not only potent and selective inhibition on AChE at sub-nanomolar potency (AChEIC50 = 0.12 nM, BChEIC50 = 361.52 nM) but also potent inhibition on HDAC (IC50 = 0.23 nM). Moreover, A10 exhibited inhibitory activity on Abeta1-42 self-aggregation as well as disaggregation activity on pre-formed Abeta fibrils. Furthermore, A10 exhibited antioxidant activity and metal chelating properties. Further mechanistic studies demonstrated that A10 is a pan-inhibitor of HDACs and a mixed-type inhibitor for AChE. It shown that A10 is a BBB penetrant by online prediction. Taken together, the results indicate that A10 can serve as a lead compound to develop promising candidate analogs as AD therapeutics.
Title: The Synergistic Effects of Heat Shock Protein 70 and Ginsenoside Rg1 against Tert-Butyl Hydroperoxide Damage Model In Vitro Lu D, Xu A, Mai H, Zhao J, Zhang C, Qi R, Wang H, Zhu L Ref: Oxid Med Cell Longev, 2015:437127, 2015 : PubMed
Neural stem cells (NSCs) transplanted is one of the hottest research to treat Alzheimer's disease (AD), but cholinergic neurons from stem cells were also susceptible to cell death which Heat shock protein 70 (HSP70) was affirmed to reverse. Related to cognitive impairment, cholinergic nervous cells should be investigated and ginsenoside Rg1 (G-Rg1) was considered to increase them. We chose tert-butyl hydroperoxide (t-BHP) damage model to study in vitro. Functional properties of our recombination plasmid pEGFP-C2-HSP70 were affirmed by SH-SY5Y cells. To opposite the transitory appearance of HSP70, NSCs used as the vectors of HSP70 gene overexpressed HSP70 for at least 7 days in vitro. After transfection for 3 days, G-Rg1 pretreatment for 4 hours, and coculture for 3 days, the expression of acetylcholinesterase (ChAT), synaptophysin, and the ratio of NeuN and GFAP were assessed by western blot; Morphological properties were detected by 3D reconstruction and immunofluorescence. ChAT was markedly improved in the groups contained G-Rg1. In coculture system, the ratio of neurons/astrocytes and the filaments of neurons were increased; apoptosis cells were decreased, compared to monotherapy (P < 0.05). In conclusion, we demonstrated that, as a safe cotreatment affirmed in vitro, overexpression of HSP70 in NSCs plus G-Rg1 promoted nervous cells regeneration from chronic oxidative damage.
Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.
The aim of this study was to investigate the effects of histamine H(1) and H(3) antagonists on learning and mnemonic dysfunction in mice. Two H(1) antagonists, pyrilamine and clozapine, and the prototypic H(3) antagonist thioperamide were used to study the role of histamine in mice with social isolation and repeated methamphetamine administration. Mice with social isolation and repeated methamphetamine administration showed significant disruption of prepulse inhibition as compared to both the socially-housed mice and isolation-housing mice. Furthermore, social isolation and repeated methamphetamine administration caused significant learning and mnemonic dysfunctions. Treatment with clozapine improved learning and mnemonic ability in all of the tasks. Pyrilamine treatment ameliorated performance in all the tests examined except for the passive avoidance test. Thioperamide, however, did not change the learning and mnemonic ability. Donepezil, an acetylcholinesterase inhibitor, reversed the learning and mnemonic dysfunction in all four tasks. The present study has shown that blockade of histamine H(1) receptor improved the learning and mnemonic ability in mice, raising the possibility that treatment with clozapine or pyrilamine may improve learning and mnemonic performance in certain patients with psychiatric diseases such as schizophrenic patients with cognitive dysfunction.
Childhood epilepsy is one of the main risk factors for a variety of problems involving cognition and behavior. Pentylenetetrazol (PTZ) kindling is currently an acceptable model for epilepsy research. The objectives of this study are to clarify the learning and mnemonic characteristics of PTZ kindling in developing mice, and to examine the effects of thioperamide and JNJ-5207852, two histamine H(3) receptor antagonists and donepezil, an acetylcholinesterase (AChE) inhibitor, on learning and memory deficits induced by PTZ kindling in the brains of developing mice. PTZ kindling led to learning and mnemonic deficits as assessed by social discrimination, acoustic fear conditioning, water maze and passive avoidance tests. Thioperamide and JNJ-5207852, ameliorated PTZ kindling-induced learning and mnemonic deficits in all tests except for the water maze test. In addition, the learning and mnemonic impairments induced by PTZ kindling were significantly improved by donepezil in all tests. These findings suggest that histamine and acetylcholine are involved in the different processes of learning and memory in the brain and that histamine H(3) receptor antagonists might be useful in the treatment of cognitive impairment in epilepsy.
Title: Secretion, purification, and characterization of a recombinant Aspergillus oryzae tannase in Pichia pastoris Zhong X, Peng L, Zheng S, Sun Z, Ren Y, Dong M, Xu A Ref: Protein Expr Purif, 36:165, 2004 : PubMed
Tannase (tannin acyl hydrolase) is an industrially important enzyme produced by a large number of fungi, which hydrolyzes the ester and depside bonds of gallotannins and gallic acid esters. In the present work, a tannase from Aspergillus oryzae has been cloned and expressed in Pichia pastoris. The catalytic activity of the recombinant enzyme was assayed. A secretory form of enzyme was made with the aid of Saccharomyces cerevisiae alpha-factor, and a simple procedure purification protocol yielded tannase in pure form. The productivity of secreted tannase achieved 7000 IU/L by fed-batch culture. Recombinant tannase had a molecular mass of 90 kDa, which consisted of two kinds of subunits linked by a disulfide bond(s). Our study is the first report on the heterologous expression of tannase suggesting that the P. pastoris system represents an attractive means of generating large quantities of tannase for both research and industrial purpose.
