Title: Synergism of Feeding and Digestion Regulated by the Neuropeptide F System in Ostrinia furnacalis Larvae Zhao J, Song Y, Jiang X, He L, Wei L, Zhao Z Ref: Cells, 12:, 2023 : PubMed
Feeding is crucial for the growth and survival of animals, including humans, but relatively little is known about how it is regulated. Here, we show that larval feeding in Ostrinia furnacalis is regulated by neuropeptide F (NPF, the homologous peptide of mammalian NPY) via the insulin signalling pathway in the midgut. Furthermore, the genes pi3k and mtor in the insulin pathway positively regulate alpha-amylase and lipase of the midgut by recruiting the transcription factors c-Myc and PPARgamma for binding to the promotors of these two enzymes. Importantly, we find that the feeding behaviour and the digestive system of midgut in O. furnacalis larvae are closely related and interactive in that knocking down alpha-amylase or lipase induces a reduction in larval feeding, while food-deprived larvae lead to fewer expressions of alpha-amylase and lipase. Importantly, it is the gut NPF that regulates the alpha-amylase and lipase, while variations of alpha-amylase and lipase may feed back to the brain NPF. This current study reveals a molecular feedback mechanism between feeding behaviour and the digestive system that is regulated by the conserved NPF via insulin signalling systems in the midgut of O. furnacalis larvae.
Title: New insights into the role of dipeptidyl peptidase 8 and dipeptidyl peptidase 9 and their inhibitors Cui C, Tian X, Wei L, Wang Y, Wang K, Fu R Ref: Front Pharmacol, 13:1002871, 2022 : PubMed
Dipeptidyl peptidase 8 (DPP8) and 9 (DPP9) are widely expressed in mammals including humans, mainly locate in the cytoplasm. The DPP8 and DPP9 (DPP8/9) belong to serine proteolytic enzymes, they can recognize and cleave N-terminal dipeptides of specific substrates if proline is at the penultimate position. Because the localization of DPP8/9 is different from that of DPP4 and the substrates for DPP8/9 are not yet completely clear, their physiological and pathological roles are still being further explored. In this article, we will review the recent research advances focusing on the expression, regulation, and functions of DPP8/9 in physiology and pathology status. Emerging research results have shown that DPP8/9 is involved in various biological processes such as cell behavior, energy metabolism, and immune regulation, which plays an essential role in maintaining normal development and physiological functions of the body. DPP8/9 is also involved in pathological processes such as tumorigenesis, inflammation, and organ fibrosis. In recent years, related research on immune cell pyroptosis has made DPP8/9 a new potential target for the treatment of hematological diseases. In addition, DPP8/9 inhibitors also have great potential in the treatment of tumors and chronic kidney disease.
Title: Fabrication of immobilized lipases for efficient preparation of 1,3-dioleoyl-2-palmitoylglycerol He L, Zeng C, Wei L, Xu L, Song F, Huang J, Zhong N Ref: Food Chem, 408:135236, 2022 : PubMed
This study aims to fabricate immobilized lipases for efficient preparation of 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) through acidolysis of glycerol tripalmitate (PPP). Twelve (three types) supports and five lipases were studied carefully. Among them, the immobilized Thermomyces lanuginosa lipase (TLL) samples exhibited overall better performance than that of other immobilized lipases. Particularly, organic groups functionalized SBA-15 (R-SBA-15) supported TLL (TLL@R-SBA-15) samples gave PPP conversion from 97.70 to 99.00s% and OPO content from 59.52 to 64.73s%. After optimization, PPP conversion up to 99.07s%, OPO content 73.15s% and sn-2 palmitic acid content 90.09s% were obtained with TLL@C(18)H(37)-SBA-15 as catalyst. Moreover, TLL@C(18)H(37)-SBA-15 exhibited better acidolysis performance from 50s degreesC than that from 60 to 80s degreesC, which helped inhibit acyl migration. In addition, after 5 cycles of reuse, TLL@C(18)H(37)-SBA-15 retained 81.04s% (based on OPO content) and 98.88s% (based on sn-2 palmitic acid content) of its initial activity, indicating it had an attractive prospect in future applications.
Both strigolactones (SLs) and nitric oxide (NO) are regulatory signals with diverse roles during stress responses. At present, the interaction and mechanism of SLs and NO in tomato salt tolerance remain unclear. In the current study, tomato 'Micro-Tom' was used to study the roles and interactions of SLs and NO in salinity stress tolerance. The results show that 15 microM SLs synthetic analogs GR24 and 10 microM NO donor S-nitrosoglutathione (GSNO) promoted seedling growth under salt stress. TIS108 (an inhibitor of strigolactone synthesis) suppressed the positive roles of NO in tomato growth under salt stress, indicating that endogenous SLs might be involved in NO-induced salt response in tomato seedlings. Meanwhile, under salt stress, GSNO or GR24 treatment induced the increase of endogenous SLs content in tomato seedlings. Moreover, GR24 or GSNO treatment effectively increased the content of chlorophyll, carotenoids and ascorbic acid (ASA), and enhanced the activities of antioxidant enzymes (superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase), glutathione reductase (GR) and cleavage dioxygenase (CCD) enzyme. Additionally, GSNO or GR24 treatment also up-regulated the expression of SLs synthesis genes (SlCCD7, SlCCD8, SlD27 and SlMAX1) and its signal transduction genes (SlD14 and SlMAX2) in tomato seedlings under salt stress. While, a strigolactone synthesis inhibitor TIS108 blocked the increase of endogenous SLs, chlorophyll, carotenoids and ASA content, and antioxidant enzyme, GR, CCD enzyme activity and SLs-related gene expression levels induced by GSNO. Thus, SLs may play an important role in NO-enhanced salinity tolerance in tomato seedlings by increasing photosynthetic pigment content, enhancing antioxidant capacity and improving endogenous SLs synthesis.
In this review, we argue that there is much to be learned by transferring knowledge from research on lignocellulose degradation to that on plastic. Plastic waste accumulates in the environment to hazardous levels, because it is inherently recalcitrant to biological degradation. Plants evolved lignocellulose to be resistant to degradation, but with time, fungi became capable of utilising it for their nutrition. Examples of how fungal strategies to degrade lignocellulose could be insightful for plastic degradation include how fungi overcome the hydrophobicity of lignin (e.g. production of hydrophobins) and crystallinity of cellulose (e.g. oxidative approaches). In parallel, knowledge of the methods for understanding lignocellulose degradation could be insightful such as advanced microscopy, genomic and post-genomic approaches (e.g. gene expression analysis). The known limitations of biological lignocellulose degradation, such as the necessity for physiochemical pretreatments for biofuel production, can be predictive of potential restrictions of biological plastic degradation. Taking lessons from lignocellulose degradation for plastic degradation is also important for biosafety as engineered plastic-degrading fungi could also have increased plant biomass degrading capabilities. Even though plastics are significantly different from lignocellulose because they lack hydrolysable C-C or C-O bonds and therefore have higher recalcitrance, there are apparent similarities, e.g. both types of compounds are mixtures of hydrophobic polymers with amorphous and crystalline regions, and both require hydrolases and oxidoreductases for their degradation. Thus, many lessons could be learned from fungal lignocellulose degradation.
Title: Chlorogenic acid alleviates thioacetamide-induced toxicity and promotes liver development in zebrafish (Danio rerio) through the Wnt signaling pathway Liu Y, Guo J, Zhang J, Deng Y, Xiong G, Fu J, Wei L, Lu H Ref: Aquat Toxicol, 242:106039, 2021 : PubMed
Chlorogenic acid (CGA) is a phenylpropanoid compound that is well known to improve the antioxidant capacity and other biological activities. However, the roles of CGA in the liver development of organisms are unclear. In the present study, we aimed to investigate the function of CGA in the hepatic development in thioacetamide (TAA)-induced zebrafish embryos. We found that CGA exerted certain beneficial effects on zebrafish larvae from TAA-exposed zebrafish embryos, such as increasing the liver size, body length, heart rate, acetylcholinesterase activity, and motor ability. In addition, CGA displayed an antioxidant effect on TAA-induced zebrafish embryos by enhancing the activities of superoxide dismutase (SOD), catalase (CAT), and glucose-6-phosphate dehydrogenase (G6PDH), and decreasing of the contents of malondialdehyde (MDA), reactive oxygen species (ROS), and nitric oxide (NO). The results of western blotting analysis showed that CGA inhibited cell apoptosis by increasing the levels of Bcl2 apoptosis regulator and decreasing the levels of Bcl2 associated X (Bax), apoptosis regulator and tumor protein P53. Moreover, CGA promoted cell proliferation in TAA-induced zebrafish larvae, as detected using proliferating cell nuclear antigen fluorescence immunostaining. In addition, CGA inhibited the expression of Wnt signaling pathway genes Dkk1 (encoding Dickkopf Wnt signaling pathway inhibitors), and promoted the expression of Lef1 (encoding lymphoid enhancer binding factor 1) and Wnt2bb (encoding wingless-type MMTV integration site family, member 2Bb). When the Wnt signal inhibitor IWR-1 was added, there was no significant change in liver development in the IWR-1 + TAA group compared with the IWR-1 + TAA + CGA group (p <0.05), which suggested that CGA regulates liver development via Wnt signaling pathway. Overall, our results suggested that CGA might alleviate TAA-induced toxicity in zebrafish and promote liver development through the Wnt signaling pathway, which provides a basis for the therapeutic effect of CGA on liver dysplasia.
Title: MiR-188-3p and miR-133b Suppress Cell Proliferation in Human Hepatocellular Carcinoma via Post-Transcriptional Suppression of NDRG1 Luo Z, Fan Y, Liu X, Liu S, Kong X, Ding Z, Li Y, Wei L Ref: Technol Cancer Research Treat, 20:15330338211033074, 2021 : PubMed
BACKGROUND: Previous studies reported that N-myc downstream-regulated gene 1 (NDRG1) was upregulated in various cancer tissues and decreased expression of miR-188-3p and miR-133b could suppress cell proliferation, metastasis, and invasion and induce apoptosis of cancer cells. However, the molecular mechanism of NRDG1 involved in hepatocellular carcinoma (HCC) tumorigenesis is still unknown. METHODS: The expressions of miR-188-3p, miR-133b, and NRDG1 in HCC tissues and cells were quantified by qRT-PCR and Western blot. MTT assay and transwell invasion assay were performed to evaluate cell growth and cell migration, respectively. Luciferase reporter assay were performed to determine whether miR-188-3p and miR-133b could directly bind to NRDG1 in HCC cells. RESULTS: The results showed that NRDG1 was upregulated and these 2 microRNAs were downregulated in HCC tissues. NRDG1 was negatively correlated with miR-188-3p and miR-133b in HCC tissues. MiR-188-3p and miR-133b were demonstrated to directly bind to 3'UTR of NRDG1 and inhibit its expression. Upregulation of miR-188-3p and miR-133b reduced NRDG1 expression in hepatocellular carcinoma cell lines, which consequently inhibited cell growth and cell migration. CONCLUSIONS: Our finding suggested that miR-188-3p and miR-133b exert a suppressive effect on hepatocellular carcinoma proliferation, invasion, and migration through downregulation of NDRG1.
Title: Insecticidal Activity of Artemisia vulgaris Essential Oil and Transcriptome Analysis of Tribolium castaneum in Response to Oil Exposure Gao S, Zhang K, Wei L, Wei G, Xiong W, Lu Y, Zhang Y, Gao A, Li B Ref: Front Genet, 11:589, 2020 : PubMed
Red flour beetle (Tribolium castaneum) is one of the most destructive pests of stored cereals worldwide. The essential oil (EO) of Artemisia vulgaris (mugwort) is known to be a strong toxicant that inhibits the growth, development, and reproduction of T. castaneum. However, the molecular mechanisms underlying the toxic effects of A. vulgaris EO on T. castaneum remain unclear. Here, two detoxifying enzymes, carboxylesterase (CarEs) and cytochrome oxidase P450 (CYPs), were dramatically increased in red flour beetle larvae when they were exposed to A. vulgaris EO. Further, 758 genes were differentially expressed between EO treated and control samples. Based on Gene Ontology (GO) analysis, numerous differentially expressed genes (DEGs) were enriched for terms related to the regulation of biological processes, response to stimulus, and antigen processing and presentation. Our results indicated that A. vulgaris EO disturbed the antioxidant activity in larvae and partially inhibited serine protease (SP), cathepsin (CAT), and lipase signaling pathways, thus disrupting larval development and reproduction as well as down-regulating the stress response. Moreover, these DEGs showed that A. vulgaris indirectly affected the development and reproduction of beetles by inducing the expression of genes encoding copper-zinc-superoxide dismutase (CuZnSOD), heme peroxidase (HPX), antioxidant enzymes, and transcription factors. Moreover, the majority of DEGs were mapped to the drug metabolism pathway in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Notably, the following genes were detected: 6 odorant binding proteins (OBPs), 5 chemosensory proteins (CSPs), 14 CYPs, 3 esterases (ESTs), 5 glutathione S-transferases (GSTs), 6 UDP-glucuronosyltransferases (UGTs), and 2 multidrug resistance proteins (MRPs), of which 8 CYPs, 2 ESTs, 2 GSTs, and 3 UGTs were up-regulated dramatically after exposure to A. vulgaris EO. The residual DEGs were significantly down-regulated in EO exposed larvae, implying that partial compensation of metabolism detoxification existed in treated beetles. Furthermore, A. vulgaris EO induced overexpression of OBP/CYP, and RNAi against these genes significantly increased mortality of larvae exposed to EO, providing further evidence for the involvement of OBP/CYP in EO metabolic detoxification in T. castaneum. Our results provide an overview of the transcriptomic changes in T. castaneum in response to A. vulgaris EO.
Title: Single-particle enumeration-based ultrasensitive enzyme activity quantification with fluorescent polymer nanoparticles Han Y, Ye Z, Wang F, Chen T, Wei L, Chen L, Xiao L Ref: Nanoscale, 11:14793, 2019 : PubMed
Acetylcholinesterase (AChE) plays a vital role in nerve conduction through rapidly hydrolyzing the neurotransmitter acetylcholine (ACh) and is correlated with Alzheimer's disease. In this work, a label-free single-particle enumeration (SPE) method for the quantitative detection of acetylcholinesterase (AChE) activity is developed. The design is based on the fluorescence resonance energy transfer (FRET) between fluorescent conjugated polymer nanoparticles (FCPNPs) and MnO2 nanosheets. The fluorescence of FCPNPs can be effectively quenched by MnO2 nanosheets via hydrogen bonding interaction. In the presence of acetylcholinesterase (AChE), acetylthiocholine (ATCh) could be hydrolyzed to thiocholine (TCh), which can reduce MnO2 to Mn2+ and trigger the decomposition of MnO2 nanosheets. As a result, the fluorescence of FCPNPs is restored. Taking advantage of the superior brightness and stable fluorescence emission from individual FCPNPs, the accurate quantification of AChE is achieved by statistically counting the fluorescent particles on the glass slide surface. A linear range from 5 to 1600 muU mL-1 is obtained for AChE assay and the limit-of-detection (LOD) is 1.02 muU mL-1, which is far below the spectroscopic measurements in bulk solution. In the human serum sample, satisfactory recovery efficiencies are determined in a range of 91.0%-103.0%. Furthermore, pesticide carbaryl as an inhibitor of AChE activity was detected. The LOD is 1.12 pg mL-1 with linear responses ranging from 5 to 300 pg mL-1, which demonstrates the feasibility of this approach for AChE inhibitor screening. As a consequence, the label-free SPE-based method affords a promising platform for the sensitive detection of target molecules in the future.
Title: Latrophilin mediates insecticides susceptibility and fecundity through two carboxylesterases, esterase4 and esterase6, in Tribolium castaneum Wei L, Gao S, Xiong W, Liu J, Mao J, Lu Y, Song X, Li B Ref: Bull Entomol Res, :1, 2019 : PubMed
Latrophilin (LPH) is known as an adhesion G-protein-coupled receptor which involved in multiple physiological processes in organisms. Previous studies showed that lph not only involved the susceptibility to anticholinesterase insecticides but also affected fecundity in Tribolium castaneum. However, its regulatory mechanisms in these biological processes are still not clear. Here, we identified two potential downstream carboxylesterase (cce) genes of Tclph, esterase4 and esterase6, and further characterized their interactions with Tclph. After treatment of T. castaneum larvae with carbofuran or dichlorvos insecticides, the transcript levels of Tcest4 and Tcest6 were significantly induced from 12 to 72 h. RNAi against Tcest4 or Tcest6 led to the higher mortality compared with the controls after the insecticides treatment, suggesting that these two genes play a vital role in detoxification of insecticides in T. castaneum. Furthermore, with insecticides exposure to Tclph knockdown beetles, the expression of Tcest4 was upregulated but Tcest6 was downregulated, indicating that beetles existed a compensatory response against the insecticides. Additionally, RNAi of Tcest6 resulted in 43% reductions in female egg laying and completely inhibited egg hatching, which showed the similar phenotype as that of Tclph knockdown. These results indicated that Tclph affected fecundity by positively regulating Tcest6 expression. Our findings will provide a new insight into the molecular mechanisms of Tclph involved in physiological functions in T. castaneum.
OBJECTIVE Respiratory dysfunction is the leading cause of mortality following upper cervical spinal cord injury (SCI). The authors' previous study suggested that vagus nerve (VN) and phrenic nerve (PN) anastomosis could partially improve respiratory function in rabbits that had been subjected to PN transection. As a branch of the VN and a motor fiber-dominated nerve, the recurrent laryngeal nerve (RLN) seems a better choice to anastomose with the PN for respiratory function restoration after upper cervical SCI. This study was designed to determine whether RLN-PN anastomosis could restore the respiratory function after upper cervical SCI in rabbits. METHODS Twelve male New Zealand rabbits were randomly divided into 3 groups: 1) sham group (no injury), 2) transection group (right RLN and PN were transected), and 3) bridge group (transected right RLN and PN were immediately anastomosed). Spontaneous discharges of the RLN and PN were compared using a bio-signal collection system. RLN and PN cross sections were stained for acetylcholinesterase (AChE), and the numbers of motor fibers were compared. Three months after the initial surgical procedures, the movement of the diaphragm was assessed using a digital subtraction angiography (DSA) system, and discharges from the right diaphragm muscle were recorded. Toluidine blue staining, electron microscopy, and staining for AChE were used to assess whether motor fibers from the RLN regenerated into the PN, and sections of diaphragm were examined after AChE staining to assess the motor endplates. RESULTS Both the RLN and PN exhibited highly rhythmic discharges, synchronized with respiration, and most fibers in the RLN and PN were found to be motor fibers. Numerous myelinated fibers were observed in anastomosed PN using toluidine blue staining and electron microscopy. Staining for AChE showed that those regenerated fibers had typical characteristics of motor fibers, and motor endplates with typical morphological characteristics were observed in the diaphragm. Reestablished rhythmic contraction of the hemidiaphragm was directly observed using the DSA system, and rhythmic spontaneous discharge was recorded from the reinnervated hemidiaphragm using the bio-signal collection system. CONCLUSIONS Motor fibers from the RLN could regenerate into the PN after end-to-end anastomosis and reinnervate the denervated hemidiaphragm in rabbits. Those regenerated motor fibers restored rhythmic and autonomic movement of the paralyzed diaphragm. These results suggest that the RLN is an optimal donor nerve to anastomose with the PN in order to reestablish the autonomic movement of paralyzed diaphragms after high-level SCI.
Targeting of the human ribosome is an unprecedented therapeutic modality with a genome-wide selectivity challenge. A liver-targeted drug candidate is described that inhibits ribosomal synthesis of PCSK9, a lipid regulator considered undruggable by small molecules. Key to the concept was the identification of pharmacologically active zwitterions designed to be retained in the liver. Oral delivery of the poorly permeable zwitterions was achieved by prodrugs susceptible to cleavage by carboxylesterase 1. The synthesis of select tetrazole prodrugs was crucial. A cell-free in vitro translation assay containing human cell lysate and purified target mRNA fused to a reporter was used to identify active zwitterions. In vivo PCSK9 lowering by oral dosing of the candidate prodrug and quantification of the drug fraction delivered to the liver utilizing an oral positron emission tomography (18) F-isotopologue validated our liver-targeting approach.
Title: Pratensein attenuates Abeta-induced cognitive deficits in rats: Enhancement of synaptic plasticity and cholinergic function Wei L, Lv S, Huang Q, Wei J, Zhang S, Huang R, Lu Z, Lin X Ref: Fitoterapia, 101C:208, 2015 : PubMed
An isoflavone was isolated from Trifolium pratense using bioassay-guided screening. The structure of this natural compound was elucidated based on its spectral data, and it was identified as pratensein. The protective effect of pratensein was evaluated using a cognitive impairment model induced by injecting amyloid beta (1-42) (Abeta1-42) into the bilateral hippocampus of rats. The results showed that pratensein treatment significantly protected against Abeta1-42-induced cognitive impairments, as evidenced by the improvement in learning and memory and the attenuation of neuronal degeneration and apoptosis in hippocampus. Analysis of the potential mechanisms of action showed that pratensein significantly decreased inflammatory indicators such as MDA, NO, nNOS, IL-1beta and TNF-alpha. Pratensein markedly decreased the content and deposition of beta-amyloid peptide through regulating the expressions of Abeta-related genes including APP, BACE1, CatB, NEP and IDE. Moreover, pratensein significantly increased the expressions of synapse plasticity-related proteins, i.e., PSD-95, p-NMDAR1, p-CaMKII, p-PKACbeta, PKCgamma, p-CREB and BDNF. In addition, pratensein significantly decreased the activity of cholinesterase, then subsequently elevated the level of acetylcholine. In summary, our study indicated that pratensein may have a likely protective effect against Alzheimer's disease (AD) via improving synaptic plasticity and increasing cholinesterase activity.
Title: A cold-adapted, solvent and salt tolerant esterase from marine bacterium Psychrobacter pacificensis Wu G, Zhang X, Wei L, Kumar A, Mao T, Liu Z Ref: Int J Biol Macromol, 81:180, 2015 : PubMed
Lipolytic enzymes with unique physico-chemical characteristics are gaining more attention for their immense industrial importance. In this study, a novel lipolytic enzyme (Est11) was cloned from the genomic library of a marine bacterium Psychrobacter pacificensis. The enzyme was expressed in Escherichia coli and purified to homogeneity with molecular mass of 32.9kDa. The recombinant Est11 was able to hydrolyze short chain esters (C2-C8) and displayed an optimum activity against butyrate ester (C4). The optimal temperature and pH were 25 degrees C and 7.5, respectively. Est11 retained more than 70% of its original activity at 10 degrees C, suggesting that it was a cold-active esterase. The enzyme was highly active and stable at high concentration of NaCl (5M). Further, incubation with ethanol, isopropanol, propanediol, DMSO, acetonitrile, and glycerol rendered remarkable positive effects on Est11 activity. Typically, even at the concentration of 30% (v/v), ethanol, DMSO, and propanediol increased Est11 activity by 1.3, 2.0, and 2.4-folds, respectively. This new robust enzyme with remarkable properties like cold-adaptability, exceptional tolerance to salt and organic solvents provides us a promising candidate to meet the needs of some harsh industrial processes.
Title: The structural basis of the Tle4-Tli4 complex reveals the self-protection mechanism of H2-T6SS in Pseudomonas aeruginosa Lu D, Zheng Y, Liao N, Wei L, Xu B, Liu X, Liu J Ref: Acta Crystallographica D Biol Crystallogr, 70:3233, 2014 : PubMed
The type VI secretion system (T6SS) has recently been demonstrated to mediate interbacterial competition and to discriminate between self and nonself. T6SS+ bacteria employ toxic effectors to inhibit rival cells and concurrently use effector cognate immunity proteins to protect their sibling cells. The effector and immunity pairs (E-I pairs) endow the bacteria with a great advantage in niche competition. Tle4-Tli4 (PA1510-PA1509) is a newly identified E-I pair that is controlled by H2-T6SS in Pseudomonas aeruginosa. Tle4 exhibits phospholipase activity, which destroys the cell membrane of rival cells, and the periplasm-located Tli4 in donor cells eliminates this toxic effect of Tle4. In this paper, the structure of the Tle4-Tli4 complex is reported at 1.75 A resolution. Tle4 consists of two domains: a conserved alpha/beta-hydrolase domain and an unusual cap domain in which two lid regions (lid1 and lid2) display a closed conformation that buries the catalytic triad in a deep funnel. Tli4 also displays a two-domain structure, in which a large lobe and a small lobe form a crab claw-like conformation. Tli4 uses this crab claw to grasp the cap domain of Tle4, especially the lid2 region, which prevents the interfacial activation of Tle4 and thus causes enzymatic dysfunction of Tle4 in sister cells.
The nonhuman primates most commonly used in medical research are from the genus Macaca. To better understand the genetic differences between these animal models, we present high-quality draft genome sequences from two macaque species, the cynomolgus/crab-eating macaque and the Chinese rhesus macaque. Comparison with the previously sequenced Indian rhesus macaque reveals that all three macaques maintain abundant genetic heterogeneity, including millions of single-nucleotide substitutions and many insertions, deletions and gross chromosomal rearrangements. By assessing genetic regions with reduced variability, we identify genes in each macaque species that may have experienced positive selection. Genetic divergence patterns suggest that the cynomolgus macaque genome has been shaped by introgression after hybridization with the Chinese rhesus macaque. Macaque genes display a high degree of sequence similarity with human disease gene orthologs and drug targets. However, we identify several putatively dysfunctional genetic differences between the three macaque species, which may explain functional differences between them previously observed in clinical studies.
The synthesis, selectivity, rat pharmacokinetic profile, and drug metabolism profiles of a series of potent fluoroolefin-derived DPP-4 inhibitors (4) are reported. A radiolabeled fluoroolefin 33 was shown to possess a high propensity to form reactive metabolites, thus revealing a potential liability for this class of DPP-4 inhibitors.
anti-Substituted beta-methylphenylalanine derived amides have been shown to be potent DPP-IV inhibitors exhibiting excellent selectivity over both DPP8 and DPP9. The optimized compound exhibited good pharmacokinetic profiles in three preclinical species.
A novel series of oxadiazole based amides have been shown to be potent DPP-4 inhibitors. The optimized compound 43 exhibited excellent selectivity over a variety of DPP-4 homologs.
anti-Substituted beta-methylphenylalanine derived amides have been shown to be potent DPP-IV inhibitors exhibiting excellent selectivity over both DPP8 and DPP9. These are among the most potent compounds reported to date lacking an electrophilic trap. The most potent compound among these is 5-oxo-1,2,4-oxadiazole 44, which is a 3 nM DPP-IV inhibitor.
A large-scale assay was performed by transfecting 29,910 individual cDNA clones derived from human placenta, fetus, and normal liver tissues into human hepatoma cells and 22,926 cDNA clones into mouse NIH 3T3 cells. Based on the results of colony formation in hepatoma cells and foci formation in NIH 3T3 cells, 3,806 cDNA species (8,237 clones) were found to possess the ability of either stimulating or inhibiting cell growth. Among them, 2,836 (6,958 clones) were known genes, 372 (384 clones) were previously unrecognized genes, and 598 (895 clones) were unigenes of uncharacterized structure and function. A comprehensive analysis of the genes and the potential mechanisms for their involvement in the regulation of cell growth is provided. The genes were classified into four categories: I, genes related to the basic cellular mechanism for growth and survival; II, genes related to the cellular microenvironment; III, genes related to host-cell systemic regulation; and IV, genes of miscellaneous function. The extensive growth-regulatory activity of genes with such highly diversified functions suggests that cancer may be related to multiple levels of cellular and systemic controls. The present assay provides a direct genomewide functional screening method. It offers a better understanding of the basic machinery of oncogenesis, including previously undescribed systemic regulatory mechanisms, and also provides a tool for gene discovery with potential clinical applications.
Title: Synaptic transmission deficits in Caenorhabditis elegans synaptobrevin mutants Nonet ML, Saifee O, Zhao H, Rand JB, Wei L Ref: Journal of Neuroscience, 18:70, 1998 : PubMed
Synaptobrevins are vesicle-associated proteins implicated in neurotransmitter release by both biochemical studies and perturbation experiments that use botulinum toxins. To test these models in vivo, we have isolated and characterized the first synaptobrevin mutants in metazoans and show that neurotransmission is severely disrupted in mutant animals. Mutants lacking snb-1 die just after completing embryogenesis. The dying animals retain some capability for movement, although they are extremely uncoordinated and incapable of feeding. We also have isolated and characterized several hypomorphic snb-1 mutants. Although fully viable, these mutants exhibit a variety of behavioral abnormalities that are consistent with a general defect in the efficacy of synaptic transmission. The viable mutants are resistant to the acetylcholinesterase inhibitor aldicarb, indicating that cholinergic transmission is impaired. Extracellular recordings from pharyngeal muscle also demonstrate severe defects in synaptic transmission in the mutants. The molecular lesions in the hypomorphic alleles reside on the hydrophobic face of a proposed amphipathic-helical region implicated biochemically in interacting with the t-SNAREs syntaxin and SNAP-25. Finally, we demonstrate that double mutants lacking both the v-SNAREs synaptotagmin and snb-1 are phenotypically similar to snb-1 mutants and less severe than syntaxin mutants. Our work demonstrates that synaptobrevin is essential for viability and is required for functional synaptic transmission. However, our analysis also suggests that transmitter release is not completely eliminated by removal of either one or both v-SNAREs.
Title: The caenorhabditis elegans unc-64 locus encodes a syntaxin that interacts genetically with synaptobrevin Saifee O, Wei L, Nonet ML Ref: Molecular Biology of the Cell, 9:1235, 1998 : PubMed
We describe the molecular cloning and characterization of the unc-64 locus of Caenorhabditis elegans. unc-64 expresses three transcripts, each encoding a molecule with 63-64% identity to human syntaxin 1A, a membrane- anchored protein involved in synaptic vesicle fusion. Interestingly, the alternative forms of syntaxin differ only in their C-terminal hydrophobic membrane anchors. The forms are differentially expressed in neuronal and secretory tissues; genetic evidence suggests that these forms are not functionally equivalent. A complete loss-of-function mutation in unc-64 results in a worm that completes embryogenesis, but arrests development shortly thereafter as a paralyzed L1 larva, presumably as a consequence of neuronal dysfunction. The severity of the neuronal phenotypes of C. elegans syntaxin mutants appears comparable to those of Drosophila syntaxin mutants. However, nematode syntaxin appears not to be required for embryonic development, for secretion of cuticle from the hypodermis, or for the function of muscle, in contrast to Drosophila syntaxin, which appears to be required in all cells. Less severe viable unc-64 mutants exhibit a variety of behavioral defects and show strong resistance to the acetylcholinesterase inhibitor aldicarb. Extracellular physiological recordings from pharyngeal muscle of hypomorphic mutants show alterations in the kinetics of transmitter release. The lesions in the hypomorphic alleles map to the hydrophobic face of the H3 coiled-coil domain of syntaxin, a domain that in vitro mediates physical interactions with similar coiled-coil domains in SNAP-25 and synaptobrevin. Furthermore, the unc-64 syntaxin mutants exhibit allele-specific genetic interactions with mutants carrying lesions in the coiled-coil domain of synaptobrevin, providing in vivo evidence for the significance of these domains in regulating synaptic vesicle fusion.
