Type 2 diabetes is thought to involve a compromised β cell differentiation state, but the mechanisms underlying this dysfunction remain unclear. Here, we report a key role for the TF PAX6 in the maintenance of adult β cell identity and function. PAX6 was downregulated in β cells of diabetic
Avital Swisa, Dana Avrahami, Noa Eden, Jia Zhang, Eseye Feleke, Tehila Dahan, Yamit Cohen-Tayar, Miri Stolovich-Rain, Klaus H. Kaestner, Benjamin Glaser, Ruth Ashery-Padan, Yuval Dor
The recognition of β cell dedifferentiation in type 2 diabetes raises the translational relevance of mechanisms that direct and maintain β cell identity. LIM domain–binding protein 1 (LDB1) nucleates multimeric transcriptional complexes and establishes promoter-enhancer looping, thereby directing fate assignment and maturation of progenitor populations. Many terminally differentiated endocrine cell types, however, remain enriched for LDB1, but its role is unknown. Here, we have demonstrated a requirement for LDB1 in maintaining the terminally differentiated status of pancreatic β cells. Inducible ablation of LDB1 in mature β cells impaired insulin secretion and glucose homeostasis. Transcriptomic analysis of LDB1-depleted β cells revealed the collapse of the terminally differentiated gene program, indicated by a loss of β cell identity genes and induction of the endocrine progenitor factor neurogenin 3 (NEUROG3). Lineage tracing confirmed that LDB1-depleted, insulin-negative β cells express NEUROG3 but do not adopt alternate endocrine cell fates. In primary mouse islets, LDB1 and its LIM homeodomain–binding partner islet 1 (ISL1) were coenriched at chromatin sites occupied by pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1), forkhead box A2 (FOXA2), and NK2 homeobox 2 (NKX2.2) — factors that co-occupy active enhancers in 3D chromatin domains in human islets. Indeed, LDB1 was enriched at active enhancers in human islets. Thus, LDB1 maintains the terminally differentiated state of β cells and is a component of active enhancers in both murine and human islets.
Benjamin N. Ediger, Hee-Woong Lim, Christine Juliana, David N. Groff, LaQueena T. Williams, Giselle Dominguez, Jin-Hua Liu, Brandon L. Taylor, Erik R. Walp, Vasumathi Kameswaran, Juxiang Yang, Chengyang Liu, Chad S. Hunter, Klaus H. Kaestner, Ali Naji, Changhong Li, Maike Sander, Roland Stein, Lori Sussel, Kyoung-Jae Won, Catherine Lee May, Doris A. Stoffers
Prader-Willi syndrome (PWS) is caused by a loss of paternally expressed genes in an imprinted region of chromosome 15q. Among the canonical PWS phenotypes are hyperphagic obesity, central hypogonadism, and low growth hormone (GH). Rare microdeletions in PWS patients define a 91-kb minimum critical deletion region encompassing 3 genes, including the noncoding RNA gene
Lisa C. Burnett, Charles A. LeDuc, Carlos R. Sulsona, Daniel Paull, Richard Rausch, Sanaa Eddiry, Jayne F. Martin Carli, Michael V. Morabito, Alicja A. Skowronski, Gabriela Hubner, Matthew Zimmer, Liheng Wang, Robert Day, Brynn Levy, Ilene Fennoy, Beatrice Dubern, Christine Poitou, Karine Clement, Merlin G. Butler, Michael Rosenbaum, Jean Pierre Salles, Maithe Tauber, Daniel J. Driscoll, Dieter Egli, Rudolph L. Leibel
Tuberous sclerosis complex (TSC) is an autosomal dominant tumor-suppressor gene syndrome caused by inactivating mutations in either
Juxiang Cao, Magdalena E. Tyburczy, Joel Moss, Thomas N. Darling, Hans R. Widlund, David J. Kwiatkowski
Malignant tumors develop through multiple steps of initiation and progression, and tumor initiation is of singular importance in tumor prevention, diagnosis, and treatment. However, the molecular mechanism whereby a signaling network of interacting pathways restrains proliferation in normal cells and prevents tumor initiation is still poorly understood. Here, we have reported that the Hippo, Wnt/β-catenin, and Notch pathways form an interacting network to maintain liver size and suppress hepatocellular carcinoma (HCC). Ablation of the mammalian Hippo kinases
Wantae Kim, Sanjoy Kumar Khan, Jelena Gvozdenovic-Jeremic, Youngeun Kim, Jason Dahlman, Hanjun Kim, Ogyi Park, Tohru Ishitani, Eek-hoon Jho, Bin Gao, Yingzi Yang
Retinitis pigmentosa (RP) encompasses a diverse group of Mendelian disorders leading to progressive degeneration of rods and then cones. For reasons that remain unclear, diseased RP photoreceptors begin to deteriorate, eventually leading to cell death and, consequently, loss of vision. Here, we have hypothesized that RP associated with mutations in phosphodiesterase-6 (PDE6) provokes a metabolic aberration in rod cells that promotes the pathological consequences of elevated cGMP and Ca2+, which are induced by the
Lijuan Zhang, Jianhai Du, Sally Justus, Chun-Wei Hsu, Luis Bonet-Ponce, Wen-Hsuan Wu, Yi-Ting Tsai, Wei-Pu Wu, Yading Jia, Jimmy K. Duong, Vinit B. Mahajan, Chyuan-Sheng Lin, Shuang Wang, James B. Hurley, Stephen H. Tsang
MHC class I–associated peptides (MAPs) define the immune self for CD8+ T lymphocytes and are key targets of cancer immunosurveillance. Here, the goals of our work were to determine whether the entire set of protein-coding genes could generate MAPs and whether specific features influence the ability of discrete genes to generate MAPs. Using proteogenomics, we have identified 25,270 MAPs isolated from the B lymphocytes of 18 individuals who collectively expressed 27 high-frequency HLA-A,B allotypes. The entire MAP repertoire presented by these 27 allotypes covered only 10% of the exomic sequences expressed in B lymphocytes. Indeed, 41% of expressed protein-coding genes generated no MAPs, while 59% of genes generated up to 64 MAPs, often derived from adjacent regions and presented by different allotypes. We next identified several features of transcripts and proteins associated with efficient MAP production. From these data, we built a logistic regression model that predicts with good accuracy whether a gene generates MAPs. Our results show preferential selection of MAPs from a limited repertoire of proteins with distinctive features. The notion that the MHC class I immunopeptidome presents only a small fraction of the protein-coding genome for monitoring by the immune system has profound implications in autoimmunity and cancer immunology.
Hillary Pearson, Tariq Daouda, Diana Paola Granados, Chantal Durette, Eric Bonneil, Mathieu Courcelles, Anja Rodenbrock, Jean-Philippe Laverdure, Caroline Côté, Sylvie Mader, Sébastien Lemieux, Pierre Thibault, Claude Perreault
Fanconi anemia (FA) is a recessive genetic disease characterized by congenital abnormalities, chromosome instability, progressive bone marrow failure (BMF), and a strong predisposition to cancer. Twenty FA genes have been identified, and the FANC proteins they encode cooperate in a common pathway that regulates DNA crosslink repair and replication fork stability. We identified a child with severe BMF who harbored biallelic inactivating mutations of the translesion DNA synthesis (TLS) gene
Dominique Bluteau, Julien Masliah-Planchon, Connor Clairmont, Alix Rousseau, Raphael Ceccaldi, Catherine Dubois d’Enghien, Olivier Bluteau, Wendy Cuccuini, Stéphanie Gachet, Régis Peffault de Latour, Thierry Leblanc, Gérard Socié, André Baruchel, Dominique Stoppa-Lyonnet, Alan D. D’Andrea, Jean Soulier
The telomerase RNA component (TERC) is a critical determinant of cellular self-renewal. Poly(A)-specific ribonuclease (PARN) is required for posttranscriptional maturation of TERC.
Baris Boyraz, Diane H. Moon, Matthew Segal, Maud Z. Muosieyiri, Asli Aykanat, Albert K. Tai, Patrick Cahan, Suneet Agarwal
The structural maintenance of chromosomes (SMC) family of proteins supports mitotic proliferation, meiosis, and DNA repair to control genomic stability. Impairments in chromosome maintenance are linked to rare chromosome breakage disorders. Here, we have identified a chromosome breakage syndrome associated with severe lung disease in early childhood. Four children from two unrelated kindreds died of severe pulmonary disease during infancy following viral pneumonia with evidence of combined T and B cell immunodeficiency. Whole exome sequencing revealed biallelic missense mutations in the
Saskia N. van der Crabben, Marije P. Hennus, Grant A. McGregor, Deborah I. Ritter, Sandesh C.S. Nagamani, Owen S. Wells, Magdalena Harakalova, Ivan K. Chinn, Aaron Alt, Lucie Vondrova, Ron Hochstenbach, Joris M. van Montfrans, Suzanne W. Terheggen-Lagro, Stef van Lieshout, Markus J. van Roosmalen, Ivo Renkens, Karen Duran, Isaac J. Nijman, Wigard P. Kloosterman, Eric Hennekam, Jordan S. Orange, Peter M. van Hasselt, David A. Wheeler, Jan J. Palecek, Alan R. Lehmann, Antony W. Oliver, Laurence H. Pearl, Sharon E. Plon, Johanne M. Murray, Gijs van Haaften
Risk for ischemic stroke has a strong genetic basis, but heritable factors also contribute to the extent of damage after a stroke has occurred. We previously identified a locus on distal mouse chromosome 7 that contributes over 50% of the variation in postischemic cerebral infarct volume observed between inbred strains. Here, we used ancestral haplotype analysis to fine-map this locus to 12 candidate genes. The gene encoding the IL-21 receptor (
Han Kyu Lee, Sehoon Keum, Huaxin Sheng, David S. Warner, Donald C. Lo, Douglas A. Marchuk
Hydrops fetalis describes fluid accumulation in at least 2 fetal compartments, including abdominal cavities, pleura, and pericardium, or in body tissue. The majority of hydrops fetalis cases are nonimmune conditions that present with generalized edema of the fetus, and approximately 15% of these nonimmune cases result from a lymphatic abnormality. Here, we have identified an autosomal dominant, inherited form of lymphatic-related (nonimmune) hydrops fetalis (LRHF). Independent exome sequencing projects on 2 families with a history of in utero and neonatal deaths associated with nonimmune hydrops fetalis uncovered 2 heterozygous missense variants in the gene encoding Eph receptor B4 (
Silvia Martin-Almedina, Ines Martinez-Corral, Rita Holdhus, Andres Vicente, Elisavet Fotiou, Shin Lin, Kjell Petersen, Michael A. Simpson, Alexander Hoischen, Christian Gilissen, Heather Jeffery, Giles Atton, Christina Karapouliou, Glen Brice, Kristiana Gordon, John W. Wiseman, Marianne Wedin, Stanley G. Rockson, Steve Jeffery, Peter S. Mortimer, Michael P. Snyder, Siren Berland, Sahar Mansour, Taija Makinen, Pia Ostergaard
Homocystinuria, which typically results from cystathionine β-synthase (CBS) deficiency, is the most common defect of sulfur amino acid metabolism. CBS condenses homocysteine and serine to cystathionine that is then converted to cysteine. Individuals with homocystinuria have markedly elevated plasma levels of homocysteine and methionine and reduced concentrations of cystathionine and cysteine. Clinical disease manifestations include thromboembolism and neuropsychiatric, ocular, and skeletal complications. Here, we have shown that administration of PEGylated CBS into the circulation of homocystinuria model mice alters the extra- and intracellular equilibrium of sulfur amino acids, resulting in a decrease of approximately 75% in plasma total homocysteine (tHcy) and normalization of cysteine concentrations. Moreover, the decrease in homocysteine and the normalization of cysteine in PEGylated CBS–treated model mice were accompanied by improvement of histopathological liver symptoms and increased survival. Together, these data suggest that CBS enzyme replacement therapy (ERT) is a promising approach for the treatment of homocystinuria and that ERT for metabolic diseases may not necessitate introduction of the deficient enzyme into its natural intracellular compartment.
Erez M. Bublil, Tomas Majtan, Insun Park, Richard S. Carrillo, Helena Hůlková, Jakub Krijt, Viktor Kožich, Jan P. Kraus
The alternatively spliced products of
John M. Lee, Chika Nobumori, Yiping Tu, Catherine Choi, Shao H. Yang, Hea-Jin Jung, Timothy A. Vickers, Frank Rigo, C. Frank Bennett, Stephen G. Young, Loren G. Fong
Selenium is a trace element that is essential for human health and is incorporated into more than 25 human selenocysteine-containing (Sec-containing) proteins via unique Sec-insertion machinery that includes a specific, nuclear genome–encoded, transfer RNA (tRNA[Ser]Sec). Here, we have identified a human tRNA[Ser]Sec mutation in a proband who presented with a variety of symptoms, including abdominal pain, fatigue, muscle weakness, and low plasma levels of selenium. This mutation resulted in a marked reduction in expression of stress-related, but not housekeeping, selenoproteins. Evaluation of primary cells from the homozygous proband and a heterozygous parent indicated that the observed deficit in stress-related selenoprotein production is likely mediated by reduced expression and diminished 2′-O-methylribosylation at uridine 34 in mutant tRNA[Ser]Sec. Moreover, this methylribosylation defect was restored by cellular complementation with normal tRNA[Ser]Sec. This study identifies a tRNA mutation that selectively impairs synthesis of stress-related selenoproteins and demonstrates the importance of tRNA modification for normal selenoprotein synthesis.
Erik Schoenmakers, Bradley Carlson, Maura Agostini, Carla Moran, Odelia Rajanayagam, Elena Bochukova, Ryuta Tobe, Rachel Peat, Evelien Gevers, Francesco Muntoni, Pascale Guicheney, Nadia Schoenmakers, Sadaf Farooqi, Greta Lyons, Dolph Hatfield, Krishna Chatterjee
The transcription factor GATA3 is essential for the genesis and maturation of the T cell lineage, and GATA3 dysregulation has pathological consequences. Previous studies have shown that GATA3 function in T cell development is regulated by multiple signaling pathways and that the Notch nuclear effector, RBP-J, binds specifically to the
Sakie Ohmura, Seiya Mizuno, Hisashi Oishi, Chia-Jui Ku, Mary Hermann, Tomonori Hosoya, Satoru Takahashi, James Douglas Engel
Yavuz Bayram, Ender Karaca, Zeynep Coban Akdemir, Elif Ozdamar Yilmaz, Gulsen Akay Tayfun, Hatip Aydin, Deniz Torun, Sevcan Tug Bozdogan, Alper Gezdirici, Sedat Isikay, Mehmed M. Atik, Tomasz Gambin, Tamar Harel, Ayman W. El-Hattab, Wu-Lin Charng, Davut Pehlivan, Shalini N. Jhangiani, Donna M. Muzny, Ali Karaman, Tamer Celik, Ozge Ozalp Yuregir, Timur Yildirim, Ilhan A. Bayhan, Eric Boerwinkle, Richard A. Gibbs, Nursel Elcioglu, Beyhan Tuysuz, James R. Lupski
Exon skipping uses antisense oligonucleotides as a treatment for genetic diseases. The antisense oligonucleotides used for exon skipping are designed to bypass premature stop codons in the target RNA and restore reading frame disruption. Exon skipping is currently being tested in humans with dystrophin gene mutations who have Duchenne muscular dystrophy. For Duchenne muscular dystrophy, the rationale for exon skipping derived from observations in patients with naturally occurring dystrophin gene mutations that generated internally deleted but partially functional dystrophin proteins. We have now expanded the potential for exon skipping by testing whether an internal, in-frame truncation of a transmembrane protein γ-sarcoglycan is functional. We generated an internally truncated γ-sarcoglycan protein that we have termed Mini-Gamma by deleting a large portion of the extracellular domain. Mini-Gamma provided functional and pathological benefits to correct the loss of γ-sarcoglycan in a
Quan Q. Gao, Eugene Wyatt, Jeff A. Goldstein, Peter LoPresti, Lisa M. Castillo, Alec Gazda, Natalie Petrossian, Judy U. Earley, Michele Hadhazy, David Y. Barefield, Alexis R. Demonbreun, Carsten Bönnemann, Matthew Wolf, Elizabeth M. McNally
David A. Zeevi, Gheona Altarescu, Ariella Weinberg-Shukron, Fouad Zahdeh, Tama Dinur, Gaya Chicco, Yair Herskovitz, Paul Renbaum, Deborah Elstein, Ephrat Levy-Lahad, Arndt Rolfs, Ari Zimran
The genetic disorder Kabuki syndrome (KS) is characterized by developmental delay and congenital anomalies. Dominant mutations in the chromatin regulators lysine (K)–specific methyltransferase 2D (
Nina Bögershausen, I-Chun Tsai, Esther Pohl, Pelin Özlem Simsek Kiper, Filippo Beleggia, E. Ferda Percin, Katharina Keupp, Angela Matchan, Esther Milz, Yasemin Alanay, Hülya Kayserili, Yicheng Liu, Siddharth Banka, Andrea Kranz, Martin Zenker, Dagmar Wieczorek, Nursel Elcioglu, Paolo Prontera, Stanislas Lyonnet, Thomas Meitinger, A. Francis Stewart, Dian Donnai, Tim M. Strom, Koray Boduroglu, Gökhan Yigit, Yun Li, Nicholas Katsanis, Bernd Wollnik