Publicació científica

S'han trobat 1157 publicacions amb els criteris indicats.
Yamamoto M, Cid E, Yamamoto F

ABO blood group A transferases catalyze the biosynthesis of FORS blood group FORS1 antigen upon deletion of exon 3 or 4.

Blood Adv 26 Des 2017, 1 (27) 2756-2766. Epub 20 Des 2017
Evolutionarily related ABO and GBGT1 genes encode, respectively, A and B glycosyltransferases (AT and BT) and Forssman glycolipid synthase (FS), which catalyze the biosynthesis of A and B, and Forssman (FORS1) oligosaccharide antigens responsible for the ABO and FORS blood group systems. Humans are a Forssman antigen-negative species; however, rare individuals with Apae phenotype express FORS1 on their red blood cells. We previously demonstrated that the replacement of the LeuGlyGly tripeptide sequence at codons 266 to 268 of human AT with GBGT1-encoded FS-specific GlyGlyAla enabled the enzyme to produce FORS1 antigen, although the FS activity was weak. We searched for additional molecular mechanisms that might allow human AT to express FORS1. A variety of derivative expression constructs of human AT were prepared. DNA was transfected into COS1 (B3GALNT1) cells, and cell-surface expression of FORS1 was immunologically monitored. To our surprise, the deletion of exon 3 or 4, but not of exon 2 or 5, of human AT transcripts bestowed moderate FS activity, indicating that the A allele is inherently capable of producing a protein with FS activity. Because RNA splicing is frequently altered in cancer, this mechanism may explain, at least partially, the appearance of FORS1 in human cancer. Furthermore, strong FS activity was attained, in addition to AT and BT activities, by cointroducing 1 of those deletions and the GlyGlyAla substitution, possibly by the synergistic effects of altered intra-Golgi localization/conformation by the former and modified enzyme specificity by the latter.
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Van de Sompele S, Pécheux L, Couso J, Meunier A, Sanchez M, De Baere E

Functional characterization of a novel non-coding mutation "Ghent +49A > G" in the iron-responsive element of L-ferritin causing hereditary hyperferritinaemia-cataract syndrome.

Sci Rep 21 Des 2017, 7 (1) 18025. Epub 21 Des 2017
Hereditary hyperferritinaemia-cataract syndrome (HHCS) is a rare disorder usually caused by heterozygous mutations in the iron-responsive element (IRE) in the 5' untranslated region (5'UTR) of the L-ferritin gene (FTL), disturbing the binding of iron regulatory proteins (IRPs) and the post-transcriptional regulation of ferritin expression. Here, the proband of a consanguineous family displayed moderate bilateral cataracts and elevated serum ferritin in the absence of iron overload. The parents and siblings showed variable degrees of mild bilateral cataracts combined with elevated levels of circulating ferritin. Sequencing of FTL identified a novel 5'UTR mutation c.-151A > G, also named "Ghent +49A > G". The zygosity of the mutation, occurring in homozygous and heterozygous state in the proband and other affected family members respectively, correlated well with severity of ophthalmological and hematological manifestations. The substitution is expected to impair the secondary structure of the upper IRE stem. Functional characterization of +49A > G by electrophoretic mobility shift assays demonstrated a reduced binding affinity for IRP1 compared to the wild-type IRE of FTL. Overall, we have expanded the repertoire of deleterious biallelic FTL IRE mutations in HHCS with this novel +49A > G mutation, the zygosity of which correlated well with the disease expression.
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Luscieti S, Galy B, Gutierrez L, Reinke M, Couso J, Shvartsman M, Di Pascale A, Witke W, Hentze MW, Pilo Boyl P, Sanchez M

The actin-binding protein profilin 2 is a novel regulator of iron homeostasis.

Blood 26 Oct 2017, 130 (17) 1934-1945. Epub 3 Ago 2017
Cellular iron homeostasis is controlled by the iron regulatory proteins (IRPs) 1 and 2 that bind cis-regulatory iron-responsive elements (IRE) on target messenger RNAs (mRNA). We identified profilin 2 (Pfn2) mRNA, which encodes an actin-binding protein involved in endocytosis and neurotransmitter release, as a novel IRP-interacting transcript, and studied its role in iron metabolism. A combination of electrophoretic mobility shift assay experiments and bioinformatic analyses led to the identification of an atypical and conserved IRE in the 3' untranslated region of Pfn2 mRNA. Pfn2 mRNA levels were significantly reduced in duodenal samples from mice with intestinal IRP ablation, suggesting that IRPs exert a positive effect on Pfn2 mRNA expression in vivo. Overexpression of Pfn2 in HeLa and Hepa1-6 cells reduced their metabolically active iron pool. Importantly, Pfn2-deficient mice showed iron accumulation in discrete areas of the brain (olfactory bulb, hippocampus, and midbrain) and reduction of the hepatic iron store without anemia. Despite low liver iron levels, hepatic hepcidin expression remained high, likely because of compensatory activation of hepcidin by mild inflammation. Splenic ferroportin was increased probably to sustain hematopoiesis. Overall, our results indicate that Pfn2 expression is controlled by the IRPs in vivo and that Pfn2 contributes to maintaining iron homeostasis in cell lines and mice.
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Marjanović MP, Hurtado-Bagès S, Lassi M, Valero V, Malinverni R, Delage H, Navarro M, Corujo D, Guberovic I, Douet J, Gama-Perez P, Garcia-Roves PM, Ahel I, Ladurner AG, Yanes O, Bouvet P, Suelves M, Teperino R, Pospisilik JA, Buschbeck M

MacroH2A1.1 regulates mitochondrial respiration by limiting nuclear NAD(+) consumption.

Nat. Struct. Mol. Biol. 9 Oct 2017, . Epub 9 Oct 2017
Histone variants are structural components of eukaryotic chromatin that can replace replication-coupled histones in the nucleosome. The histone variant macroH2A1.1 contains a macrodomain capable of binding NAD(+)-derived metabolites. Here we report that macroH2A1.1 is rapidly induced during myogenic differentiation through a switch in alternative splicing, and that myotubes that lack macroH2A1.1 have a defect in mitochondrial respiratory capacity. We found that the metabolite-binding macrodomain was essential for sustained optimal mitochondrial function but dispensable for gene regulation. Through direct binding, macroH2A1.1 inhibits basal poly-ADP ribose polymerase 1 (PARP-1) activity and thus reduces nuclear NAD(+) consumption. The resultant accumulation of the NAD(+) precursor NMN allows for maintenance of mitochondrial NAD(+) pools that are critical for respiration. Our data indicate that macroH2A1.1-containing chromatin regulates mitochondrial respiration by limiting nuclear NAD(+) consumption and establishing a buffer of NAD(+) precursors in differentiated cells.
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Manils J, Fischer H, Climent J, Casas E, García-Martínez C, Bas J, Sukseree S, Vavouri T, Ciruela F, de Anta JM, Tschachler E, Eckhart L, Soler C

Double deficiency of Trex2 and DNase1L2 nucleases leads to accumulation of DNA in lingual cornifying keratinocytes without activating inflammatory responses.

Sci Rep 19 Set 2017, 7 (1) 11902. Epub 19 Set 2017
The cornification of keratinocytes on the surface of skin and oral epithelia is associated with the degradation of nuclear DNA. The endonuclease DNase1L2 and the exonuclease Trex2 are expressed specifically in cornifying keratinocytes. Deletion of DNase1L2 causes retention of nuclear DNA in the tongue epithelium but not in the skin. Here we report that lack of Trex2 results in the accumulation of DNA fragments in the cytoplasm of cornifying lingual keratinocytes and co-deletion of DNase1L2 and Trex2 causes massive accumulation of DNA fragments throughout the cornified layers of the tongue epithelium. By contrast, cornification-associated DNA breakdown was not compromised in the epidermis. Aberrant retention of DNA in the tongue epithelium was associated neither with enhanced expression of DNA-driven response genes, such as Ifnb, Irf7 and Cxcl10, nor with inflammation. Of note, the expression of Tlr9, Aim2 and Tmem173, key DNA sensor genes, was markedly lower in keratinocytes and keratinocyte-built tissues than in macrophages and immune tissues, and DNA-driven response genes were not induced by introduction of DNA in keratinocytes. Altogether, our results indicate that DNase1L2 and Trex2 cooperate in the breakdown and degradation of DNA during cornification of lingual keratinocytes and aberrant DNA retention is tolerated in the oral epithelium.
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Lo Re O, Fusilli C, Rappa F, Van Haele M, Douet J, Pindjakova J, Rocha SW, Pata I, Valčíková B, Uldrijan S, Yeung RS, Peixoto CA, Roskams T, Buschbeck M, Mazza T, Vinciguerra M

Induction of cancer cell stemness by depletion of macrohistone H2A1 in hepatocellular carcinoma.

Hepatology 15 Set 2017, . Epub 15 Set 2017
Hepatocellular carcinomas (HCC) contain a sub-population of cancer stem cells (CSCs), which exhibit stem-cell like features and are responsible for tumor relapse, metastasis, and chemoresistance. The development of effective treatments for HCC will depend on a molecular-level understanding of the specific pathways driving CSC emergence and stemness. MacroH2A1 is a variant of the histone H2A and an epigenetic regulator of stem cell function, where it promotes differentiation and, conversely, acts as a barrier to somatic cell reprogramming. Here we focused on the role played by the histone variant macroH2A1 as a potential epigenetic factor promoting CSC differentiation. In human HCC sections we uncovered a significant correlation between low frequencies of macroH2A1 staining and advanced, aggressive HCC subtypes with poorly-differentiated tumor phenotypes. Using HCC cell lines we found that shRNA-mediated macroH2A1 knock-down induces acquisition of CSC-like features, including the growth of significantly larger and less-differentiated tumors when injected into nude mice. MacroH2A1-depleted HCC cells also exhibited reduced proliferation, resistance to chemotherapeutic agents, and stem-like metabolic changes consistent with enhanced hypoxia responses and increased glycolysis. The loss of macroH2A1 increased expression of a panel of stemness-associated genes, and drove hyper-activation of the NF-κBp65 pathway. Blocking phosphorylation of NF-κBp65 on Ser536 inhibited the emergence of CSC-like features in HCC cells knocked-down for macroH2A1.
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Yamamoto F

Evolutionary divergence of the ABO and GBGT1 genes specifying the ABO and FORS blood group systems through chromosomal rearrangements.

Sci Rep 24 Ago 2017, 7 (1) 9375. Epub 24 Ago 2017
Human alleles at the ABO and GBGT1 genetic loci specify glycosylation polymorphism of ABO and FORS blood group systems, respectively, and their allelic basis has been elucidated. These genes are also present in other species, but presence/absence, as well as functionality/non-functionality are species-dependent. Molecular mechanisms and forces that created this species divergence were unknown. Utilizing genomic information available from GenBank and Ensembl databases, gene order maps were constructed of a chromosomal region surrounding the ABO and GBGT1 genes from a variety of vertebrate species. Both similarities and differences were observed in their chromosomal organization. Interestingly, the ABO and GBGT1 genes were found located at the boundaries of chromosomal fragments that seem to have been inverted/translocated during species evolution. Genetic alterations, such as deletions and duplications, are prevalent at the ends of rearranged chromosomal fragments, which may partially explain the species-dependent divergence of those clinically important glycosyltransferase genes.
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Klosin A, Reis K, Hidalgo-Carcedo C, Casas E, Vavouri T, Lehner B

Impaired DNA replication derepresses chromatin and generates a transgenerationally inherited epigenetic memory.

Sci Adv Ago 2017, 3 (8) e1701143. Epub 16 Ago 2017
Impaired DNA replication is a hallmark of cancer and a cause of genomic instability. We report that, in addition to causing genetic change, impaired DNA replication during embryonic development can have major epigenetic consequences for a genome. In a genome-wide screen, we identified impaired DNA replication as a cause of increased expression from a repressed transgene in Caenorhabditis elegans. The acquired expression state behaved as an "epiallele," being inherited for multiple generations before fully resetting. Derepression was not restricted to the transgene but was caused by a global reduction in heterochromatin-associated histone modifications due to the impaired retention of modified histones on DNA during replication in the early embryo. Impaired DNA replication during development can therefore globally derepress chromatin, creating new intergenerationally inherited epigenetic expression states.
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Benoit YD, Mitchell RR, Risueño RM, Orlando L, Tanasijevic B, Boyd AL, Aslostovar L, Salci KR, Shapovalova Z, Russell J, Eguchi M, Golubeva D, Graham M, Xenocostas A, Trus MR, Foley R, Leber B, Collins TJ, Bhatia M

Sam68 Allows Selective Targeting of Human Cancer Stem Cells.

Cell Chem Biol 20 Jul 2017, 24 (7) 833-844.e9. Epub 22 Jun 2017
Targeting of human cancer stem cells (CSCs) requires the identification of vulnerabilities unique to CSCs versus healthy resident stem cells (SCs). Unfortunately, dysregulated pathways that support transformed CSCs, such as Wnt/β-catenin signaling, are also critical regulators of healthy SCs. Using the ICG-001 and CWP family of small molecules, we reveal Sam68 as a previously unappreciated modulator of Wnt/β-catenin signaling within CSCs. Disruption of CBP-β-catenin interaction via ICG-001/CWP induces the formation of a Sam68-CBP complex in CSCs that alters Wnt signaling toward apoptosis and differentiation induction. Our study identifies Sam68 as a regulator of human CSC vulnerability.
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Torres-Ruiz R, Martinez-Lage M, Martin MC, Garcia A, Bueno C, Castaño J, Ramirez JC, Menendez P, Cigudosa JC, Rodriguez-Perales S

Efficient Recreation of t(11;22) EWSR1-FLI1(+) in Human Stem Cells Using CRISPR/Cas9.

Stem Cell Reports 9 Mai 2017, 8 (5) 1408-1420.
Efficient methodologies for recreating cancer-associated chromosome translocations are in high demand as tools for investigating how such events initiate cancer. The CRISPR/Cas9 system has been used to reconstruct the genetics of these complex rearrangements at native loci while maintaining the architecture and regulatory elements. However, the CRISPR system remains inefficient in human stem cells. Here, we compared three strategies aimed at enhancing the efficiency of the CRISPR-mediated t(11;22) translocation in human stem cells, including mesenchymal and induced pluripotent stem cells: (1) using end-joining DNA processing factors involved in repair mechanisms, or (2) ssODNs to guide the ligation of the double-strand break ends generated by CRISPR/Cas9; and (3) all-in-one plasmid or ribonucleoprotein complex-based approaches. We report that the generation of targeted t(11;22) is significantly increased by using a combination of ribonucleoprotein complexes and ssODNs. The CRISPR/Cas9-mediated generation of targeted t(11;22) in human stem cells opens up new avenues in modeling Ewing sarcoma.
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