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Defective insulin secretion is a feature of type 2 diabetes that results from inadequate compensatory increase in β-cell mass, decreased β-cell survival and impaired glucose-dependent insulin release. Pancreatic β-cell proliferation, survival and secretion are thought to be regulated by signalling pathways linked to G-protein coupled receptors (GPCRs), such as the glucagon-like peptide-1 (GLP-1) and the pituitary adenylate cyclase-activating polypeptide (PACAP) receptors. β-arrestin-1 serves as a multifunctional adaptor protein that mediates receptor desensitization, receptor internalization, and links GPCRs to downstream pathways such as tyrosine kinase Src, ERK1/2 or Akt/PKB. Importantly, recent studies found that β-arrestin-1 mediates GLP-1 signalling to insulin secretion, GLP-1 antiapoptotic effect by phosphorylating the proapoptotic protein Bad through ERK1/2 activation, and PACAP potentiation of glucose-induced long-lasting ERK1/2 activation controlling IRS-2 expression. Together, these novel findings reveal an important functional role for β-arrestin-1 in the regulation of insulin secretion and β-cell survival by GPCRs. 相似文献
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Emilie Lecomte Sylvie Saleun Mathieu Bolteau Aurélien Guy-Duché Oumeya Adjali Véronique Blouin Magalie Penaud-Budloo Eduard Ayuso 《Biotechnology journal》2021,16(1):2000016
Adeno-associated viral vectors (AAV) are efficient engineered tools for delivering genetic material into host cells. The commercialization of AAV-based drugs must be accompanied by the development of appropriate quality control (QC) assays. Given the potential risk of co-transfer of oncogenic or immunogenic sequences with therapeutic vectors, accurate methods to assess the level of residual DNA in AAV vector stocks are particularly important. An assay based on high-throughput sequencing (HTS) to identify and quantify DNA species in recombinant AAV batches is developed. Here, it is shown that PCR amplification of regions that have a local GC content >90% and include successive mononucleotide stretches, such as the CAG promoter, can introduce bias during DNA library preparation, leading to drops in sequencing coverage. To circumvent this problem, SSV-Seq 2.0, a PCR-free protocol for sequencing AAV vector genomes containing such sequences, is developed. The PCR-free protocol improves the evenness of the rAAV genome coverage and consequently leads to a more accurate relative quantification of residual DNA. HTS-based assays provide a more comprehensive assessment of DNA impurities and AAV vector genome integrity than conventional QC tests based on real-time PCR and are useful methods to improve the safety and efficacy of these viral vectors. 相似文献
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Hadhemi Kaddour Yosra Hamdi David Vaudry Magalie Basille Laurence Desrues Jérôme Leprince Hélène Castel Hubert Vaudry Marie‐Christine Tonon Mohamed Amri Olfa Masmoudi‐Kouki 《Journal of neurochemistry》2013,125(4):620-633
Oxidative stress, induced by various neurodegenerative diseases, initiates a cascade of events leading to apoptosis, and thus plays a critical role in neuronal injury. In this study, we have investigated the potential neuroprotective effect of the octadecaneuropeptide (ODN) on 6‐hydroxydopamine (6‐OHDA)‐induced oxidative stress and apoptosis in cerebellar granule neurons (CGN). ODN, which is produced by astrocytes, is an endogenous ligand for both central‐type benzodiazepine receptors (CBR) and a metabotropic receptor. Incubation of neurons with subnanomolar concentrations of ODN (10?18 to 10?12 M) inhibited 6‐OHDA‐evoked cell death in a concentration‐dependent manner. The effect of ODN on neuronal survival was abrogated by the metabotropic receptor antagonist, cyclo1–8[DLeu5]OP, but not by a CBR antagonist. ODN stimulated polyphosphoinositide turnover and ERK phosphorylation in CGN. The protective effect of ODN against 6‐OHDA toxicity involved the phospholipase C/ERK MAPK transduction cascade. 6‐OHDA treatment induced an accumulation of reactive oxygen species, an increase of the expression of the pro‐apoptotic gene Bax, a drop of the mitochondrial membrane potential and a stimulation of caspase‐3 activity. Exposure of 6‐OHDA‐treated cells to ODN blocked all the deleterious effects of the toxin. Taken together, these data demonstrate for the first time that ODN is a neuroprotective agent that prevents 6‐OHDA‐induced oxidative stress and apoptotic cell death. 相似文献
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Jie Chen Magalie Moinard Jianping Xu Shouxian Wang Marie Foulongne-Oriol Ruilin Zhao Kevin D. Hyde Philippe Callac 《PloS one》2016,11(5)
The internal transcribed spacer (ITS) region of the nuclear ribosomal RNA gene cluster is widely used in fungal taxonomy and phylogeographic studies. The medicinal and edible mushroom Agaricus subrufescens has a worldwide distribution with a high level of polymorphism in the ITS region. A previous analysis suggested notable ITS sequence heterogeneity within the wild French isolate CA487. The objective of this study was to investigate the pattern and potential mechanism of ITS sequence heterogeneity within this strain. Using PCR, cloning, and sequencing, we identified three types of ITS sequences, A, B, and C with a balanced distribution, which differed from each other at 13 polymorphic positions. The phylogenetic comparisons with samples from different continents revealed that the type C sequence was similar to those found in Oceanian and Asian specimens of A. subrufescens while types A and B sequences were close to those found in the Americas or in Europe. We further investigated the inheritance of these three ITS sequence types by analyzing their distribution among single-spore isolates from CA487. In this analysis, three co-dominant markers were used firstly to distinguish the homokaryotic offspring from the heterokaryotic offspring. The homokaryotic offspring were then analyzed for their ITS types. Our genetic analyses revealed that types A and B were two alleles segregating at one locus ITSI, while type C was not allelic with types A and B but was located at another unlinked locus ITSII. Furthermore, type C was present in only one of the two constitutive haploid nuclei (n) of the heterokaryotic (n+n) parent CA487. These data suggest that there was a relatively recent introduction of the type C sequence and a duplication of the ITS locus in this strain. Whether other genes were also transferred and duplicated and their impacts on genome structure and stability remain to be investigated. 相似文献
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We present ParaDB (http://abi.marseille.inserm.fr/paradb/), a new database for large-scale paralogy studies in vertebrate genomes. We intended to collect all information (sequence, mapping and phylogenetic data) needed to map and detect new paralogous regions, previously defined as Paralogons. The AceDB database software was used to generate graphical objects and to organize data. General data were automatically collated from public sources (Ensembl, GadFly and RefSeq). ParaDB provides access to data derived from whole genome sequences (Homo sapiens, Mus musculus and Drosophila melanogaster): cDNA and protein sequences, positional information, bibliographical links. In addition, we provide BLAST results for each protein sequence, InParanoid orthologs and 'In-Paralogs' data, previously established paralogy data, and, to compare vertebrates and Drosophila, orthology data. 相似文献
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A serologic survey for Toxoplasma gondii in 18 free-ranging forest mammal species (n = 456) in French Guiana was undertaken with a direct agglutination test. Serum antibody prevalence varied from 0-71%. The relationships between ecologic features of the species and seroprevalence were investigated. Terrestrial mammals were significantly more exposed to T. gondii than other mammals. This result is concordant with oral exposure to T. gondii related to ground dwelling behavior and/or carnivory. 相似文献
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Subtypes of the somatostatin receptor assemble as functional homo- and heterodimers 总被引:29,自引:0,他引:29
Rocheville M Lange DC Kumar U Sasi R Patel RC Patel YC 《The Journal of biological chemistry》2000,275(11):7862-7869
The existence of receptor dimers has been proposed for several G protein-coupled receptors. However, the question of whether G protein-coupled receptor dimers are necessary for activating or modulating normal receptor function is unclear. We address this question with somatostatin receptors (SSTRs) of which there are five distinct subtypes. By using transfected mutant and wild type receptors, as well as endogenous receptors, we provide pharmacological, biochemical, and physical evidence, based on fluorescence resonance energy transfer analysis, that activation by ligand induces SSTR dimerization, both homo- and heterodimerization with other members of the SSTR family, and that dimerization alters the functional properties of the receptor such as ligand binding affinity and agonist-induced receptor internalization and up-regulation. Double label confocal fluorescence microscopy showed that when SSTR1 and SSTR5 subtypes were coexpressed in Chinese hamster ovary-K1 cells and treated with agonist they underwent internalization and were colocalized in cytoplasmic vesicles. SSTR5 formed heterodimers with SSTR1 but not with SSTR4 suggesting that heterodimerization is a specific process that is restricted to some but not all receptor subtype combinations. Direct protein interaction between different members of the SSTR subfamily defines a new level of molecular cross-talk between subtypes of the SSTR and possibly related receptor families. 相似文献
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Vassili Valayannopoulos Coralie Haudry Valérie Serre Magalie Barth Nathalie Boddaert Jean-Baptiste Arnoux Valérie Cormier-Daire Marlène Rio Daniel Rabier Anne Vassault Arnold Munnich Jean-Paul Bonnefont Pascale de Lonlay Agnès Rötig Anne-Sophie Lebre 《Mitochondrion》2010,10(4):335-341
Deficiencies in two subunits of the succinyl-coenzyme A synthetase (SCS) have been involved in patients with encephalomyopathy and mild methylmalonic aciduria (MMA). In this study, we described three new SUCLG1 patients and performed a meta-analysis of the literature. Our report enlarges the phenotypic spectrum of SUCLG1 mutations and confirms that a characteristic metabolic profile (presence of MMA and C4-DC carnitine in urines) and basal ganglia MRI lesions are the hallmarks of SCS defects. As mitochondrial DNA depletion in muscle is not a constant finding in SUCLG1 patients, this may suggest that diagnosis should not be based on it, but also that alternative physiopathological mechanisms may be considered to explain the combined respiratory chain deficiency observed in SCS patients. 相似文献