Browsing by Author "Craigen, William J."

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    Aberrant Function of the C-Terminal Tail of HIST1H1E Accelerates Cellular Senescence and Causes Premature Aging
    (Cell Press, 2019-09-05) Flex, Elisabetta; Martinelli, Simone; Van Dijck, Anke; Ciolfi, Andrea; Cecchetti, Serena; Coluzzi, Elisa; Pannone, Luca; Andreoli, Cristina; Radio, Francesca Clementina; Pizzi, Simone; Carpentieri, Giovanna; Bruselles, Alessandro; Catanzaro, Giuseppina; Pedace, Lucia; Miele, Evelina; Carcarino, Elena; Ge, Xiaoyan; Chijiwa, Chieko; Lewis, M.E. Suzanne; Meuwissen, Marije; Kenis, Sandra; Van der Aa, Nathalie; Larson, Austin; Brown, Kathleen; Wasserstein, Melissa P.; Skotko, Brian G.; Begtrup, Amber; Person, Richard; Karayiorgou, Maria; Roos, J. Louw; Van Gassen, Koen L.; Koopmans, Marije; Bijlsma, Emilia K.; Santen, Gijs W.E.; Barge-Schaapveld, Daniela Q.C.M.; Ruivenkamp, Claudia A.L.; Hoffer, Mariette J.V.; Lalani, Seema R.; Streff, Haley; Craigen, William J.; Graham, Brett H.; van den Elzen, Annette P.M.; Kamphuis, Daan J.; Ounap, Katrin; Reinson, Karit; Pajusalu, Sander; Wojcik, Monica H.; Viberti, Clara; Di Gaetano, Cornelia; Bertini, Enrico; Petrucci, Simona; De Luca, Alessandro; Rota, Rossella; Ferretti, Elisabetta; Matullo, Giuseppe; Dallapiccola, Bruno; Sgura, Antonella; Walkiewicz, Magdalena; Kooy, R. Frank; Tartaglia, Marco; Medical and Molecular Genetics, School of Medicine
    Histones mediate dynamic packaging of nuclear DNA in chromatin, a process that is precisely controlled to guarantee efficient compaction of the genome and proper chromosomal segregation during cell division and to accomplish DNA replication, transcription, and repair. Due to the important structural and regulatory roles played by histones, it is not surprising that histone functional dysregulation or aberrant levels of histones can have severe consequences for multiple cellular processes and ultimately might affect development or contribute to cell transformation. Recently, germline frameshift mutations involving the C-terminal tail of HIST1H1E, which is a widely expressed member of the linker histone family and facilitates higher-order chromatin folding, have been causally linked to an as-yet poorly defined syndrome that includes intellectual disability. We report that these mutations result in stable proteins that reside in the nucleus, bind to chromatin, disrupt proper compaction of DNA, and are associated with a specific methylation pattern. Cells expressing these mutant proteins have a dramatically reduced proliferation rate and competence, hardly enter into the S phase, and undergo accelerated senescence. Remarkably, clinical assessment of a relatively large cohort of subjects sharing these mutations revealed a premature aging phenotype as a previously unrecognized feature of the disorder. Our findings identify a direct link between aberrant chromatin remodeling, cellular senescence, and accelerated aging.
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    Knockout of Vdac1 activates hypoxia-inducible factor through reactive oxygen species generation and induces tumor growth by promoting metabolic reprogramming and inflammation
    (BioMed Central, 2015-08-26) Brahimi-Horn, Christiane; Giuliano, Sandy; Saland, Estelle; Lacas-Gervais, Sandra; Sheiko, Tatiana; Pelletier, Joffrey; Bourget, Isabelle; Bost, Frédéric; Féral, Chloé; Boulter, Etienne; Tauc, Michel; Ivan, Mircea; Garmy-Susini, Barbara; Popa, Alexandra; Mari, Bernard; Sarry, Jean-Emmanuel; Craigen, William J.; Pouysségur, Jacques; Mazure, Nathalie M.; Department of Microbiology and Immunology, IU School of Medicine
    BACKGROUND: Mitochondria are more than just the powerhouse of cells; they dictate if a cell dies or survives. Mitochondria are dynamic organelles that constantly undergo fusion and fission in response to environmental conditions. We showed previously that mitochondria of cells in a low oxygen environment (hypoxia) hyperfuse to form enlarged or highly interconnected networks with enhanced metabolic efficacy and resistance to apoptosis. Modifications to the appearance and metabolic capacity of mitochondria have been reported in cancer. However, the precise mechanisms regulating mitochondrial dynamics and metabolism in cancer are unknown. Since hypoxia plays a role in the generation of these abnormal mitochondria, we questioned if it modulates mitochondrial function. The mitochondrial outer-membrane voltage-dependent anion channel 1 (VDAC1) is at center stage in regulating metabolism and apoptosis. We demonstrated previously that VDAC1 was post-translationally C-terminal cleaved not only in various hypoxic cancer cells but also in tumor tissues of patients with lung adenocarcinomas. Cells with enlarged mitochondria and cleaved VDAC1 were also more resistant to chemotherapy-stimulated cell death than normoxic cancer cells. RESULTS: Transcriptome analysis of mouse embryonic fibroblasts (MEF) knocked out for Vdac1 highlighted alterations in not only cancer and inflammatory pathways but also in the activation of the hypoxia-inducible factor-1 (HIF-1) signaling pathway in normoxia. HIF-1α was stable in normoxia due to accumulation of reactive oxygen species (ROS), which decreased respiration and glycolysis and maintained basal apoptosis. However, in hypoxia, activation of extracellular signal-regulated kinase (ERK) in combination with maintenance of respiration and increased glycolysis counterbalanced the deleterious effects of enhanced ROS, thereby allowing Vdac1 (-/-) MEF to proliferate better than wild-type MEF in hypoxia. Allografts of RAS-transformed Vdac1 (-/-) MEF exhibited stabilization of both HIF-1α and HIF-2α, blood vessel destabilization, and a strong inflammatory response. Moreover, expression of Cdkn2a, a HIF-1-target and tumor suppressor gene, was markedly decreased. Consequently, RAS-transformed Vdac1 (-/-) MEF tumors grew faster than wild-type MEF tumors. CONCLUSIONS: Metabolic reprogramming in cancer cells may be regulated by VDAC1 through vascular destabilization and inflammation. These findings provide new perspectives into the understanding of VDAC1 in the function of mitochondria not only in cancer but also in inflammatory diseases.
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    Pathogenic Variants in Fucokinase Cause a Congenital Disorder of Glycosylation
    (Elsevier, 2018-12-06) Ng, Bobby G.; Rosenfeld, Jill A.; Emrick, Lisa; Jain, Mahim; Burrage, Lindsay C.; Lee, Brendan; Craigen, William J.; Bearden, David R.; Graham, Brett H.; Freeze, Hudson H.; Medical and Molecular Genetics, School of Medicine
    FUK encodes fucokinase, the only enzyme capable of converting L-fucose to fucose-1-phosphate, which will ultimately be used for synthesizing GDP-fucose, the donor substrate for all fucosyltransferases. Although it is essential for fucose salvage, this pathway is thought to make only a minor contribution to the total amount of GDP-fucose. A second pathway, the major de novo pathway, involves conversion of GDP-mannose to GDP-fucose. Here we describe two unrelated individuals who have pathogenic variants in FUK and who presented with severe developmental delays, encephalopathy, intractable seizures, and hypotonia. The first individual was compound heterozygous for c.667T>C (p.Ser223Pro) and c.2047C>T (p.Arg683Cys), and the second individual was homozygous for c.2980A>C (p.Lys994Gln). Skin fibroblasts from the first individual confirmed the variants as loss of function and showed significant decreases in total GDP-[3H] fucose and [3H] fucose-1-phosphate. There was also a decrease in the incorporation of [5,6-3H]-fucose into fucosylated glycoproteins. Lys994 has previously been shown to be an important site for ubiquitin conjugation. Here, we show that loss-of-function variants in FUK cause a congenital glycosylation disorder characterized by a defective fucose-salvage pathway.