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Du Z, Iyyanki T, Lessard S, Chao M, Asbrand C, Nassar D, Klinger K, de Rinaldis E, Khader S, Chatelain C. Genome-wide association study analysis of disease severity in Acne reveals novel biological insights. medRxiv 2023:2023.11.13.23298473. [PMID: 38014089 PMCID: PMC10680891 DOI: 10.1101/2023.11.13.23298473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Acne vulgaris is a common skin disease that affects >85% of teenage young adults among which >8% develop severe lesions that leaves permanent scars. Genetic heritability studies of acne in twin cohorts have estimated that the heritability for acne is 80%. Previous genome-wide association studies (GWAS) have identified 50 genetic loci associated with increased risk of developing acne when compared to healthy individuals. However only a few studies have investigated genetic association with disease severity. GWAS of disease progression may provide a more effective approach to unveil potential disease modifying therapeutic targets. Here, we performed a multi-ethnic GWAS analysis to capture disease severity in acne patients by using individuals with normal acne as a control. Our cohort consists of a total of 2,956 participants, including 290 severe acne cases and 930 normal acne controls from FinnGen, and 522 cases and 1,214 controls from BioVU. We also performed mendelian randomization (MR), colocalization analyses and transcriptome-wide association study (TWAS) to identify putative causal genes. Lastly, we performed gene-set enrichment analysis using MAGMA to implicate biological pathways that drive disease severity in Acne. We identified two new loci associated with acne severity at the genome-wide significance level, six novel associated genes by MR, colocalization and TWAS analyses, including genes CDC7, SLC7A1, ADAM23, TTLL10, CDK20 and DNAJA4 , and 5 novel pathways by MAGMA analyses. Our study suggests that the etiologies of acne susceptibility and severity have limited overlap, with only 26% of known acne risk loci presenting nominal association with acne severity and none of the novel severity associated genes reported as associated with acne risk in previous GWAS.
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Lessard S, He C, Rajpal DK, Klinger K, Loh C, Harris T, Dumont J. Genome-Wide Association Study and Gene-Based Analysis of Participants With Hemophilia A and Inhibitors in the My Life, Our Future Research Repository. Front Med (Lausanne) 2022; 9:903838. [PMID: 35814780 PMCID: PMC9260508 DOI: 10.3389/fmed.2022.903838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Up to 30% of individuals with hemophilia A develop inhibitors to replacement factor VIII (FVIII), rendering the treatment ineffective. The underlying mechanism of inhibitor development remains poorly understood. The My Life, Our Future Research Repository (MLOF RR) has gathered F8 and F9 mutational information, phenotypic data, and biological material from over 11,000 participants with hemophilia A (HA) and B as well as carriers enrolled across US hemophilia treatment centers, including over 5,000 whole-genome sequences. Identifying genes associated with inhibitors may contribute to our understanding of why certain patients develop those neutralizing antibodies. Aim and Methods Here, we performed a genome-wide association study and gene-based analyses to identify genes associated with inhibitors in participants with HA from the MLOF RR. Results We identify a genome-wide significant association within the human leukocyte antigen (HLA) locus in participants with HA with F8 intronic inversions. HLA typing revealed independent associations with the HLA alleles major histocompatibility complex, class II, DR beta 1 (HLA DRB1*15:01) and major histocompatibility complex, class II, DQ beta 1 (DQB1*03:03). Variant aggregation tests further identified low-frequency variants within GRID2IP (glutamate receptor, ionotropic, delta 2 [GRID2] interacting protein 1) significantly associated with inhibitors. Conclusion Overall, our study confirms the association of DRB1*15:01 with FVIII inhibitors and identifies a novel association of DQB1*03:03 in individuals with HA carrying intronic inversions of F8. In addition, our results implicate GRID2IP, encoding GRID2-interacting protein, with the development of inhibitors, and suggest an unrecognized role of this gene in autoimmunity.
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Affiliation(s)
- Samuel Lessard
- Sanofi S.A., Framingham, MA, United States
- *Correspondence: Samuel Lessard,
| | - Chunla He
- American Thrombosis and Hemostasis Network, Rochester, NY, United States
| | | | | | - Christine Loh
- Bioverativ, a Sanofi Company, Waltham, MA, United States
| | - Tim Harris
- Bioverativ, a Sanofi Company, Waltham, MA, United States
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Canver MC, Tripathi P, Bullen MJ, Olshansky M, Kumar Y, Wong LH, Turner SJ, Lessard S, Pinello L, Orkin SH, Das PP. A saturating mutagenesis CRISPR-Cas9-mediated functional genomic screen identifies cis- and trans-regulatory elements of Oct4 in murine ESCs. J Biol Chem 2020; 295:15797-15809. [PMID: 32994224 DOI: 10.1074/jbc.ra120.013772] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/15/2020] [Indexed: 11/06/2022] Open
Abstract
Regulatory elements (REs) consist of enhancers and promoters that occupy a significant portion of the noncoding genome and control gene expression programs either in cis or in trans Putative REs have been identified largely based on their regulatory features (co-occupancy of ESC-specific transcription factors, enhancer histone marks, and DNase hypersensitivity) in mouse embryonic stem cells (mESCs). However, less has been established regarding their regulatory functions in their native context. We deployed cis- and trans-regulatory elements scanning through saturating mutagenesis and sequencing (ctSCAN-SMS) to target elements within the ∼12-kb cis-region (cis-REs; CREs) of the Oct4 gene locus, as well as genome-wide 2,613 high-confidence trans-REs (TREs), in mESCs. ctSCAN-SMS identified 10 CREs and 12 TREs as novel candidate REs of the Oct4 gene in mESCs. Furthermore, deletions of these candidate REs confirmed that the majority of the REs are functionally active, and CREs are more active than TREs in controlling Oct4 gene expression. A subset of active CREs and TREs physically interact with the Oct4 promoter to varying degrees; specifically, a greater number of active CREs, compared with active TREs, physically interact with the Oct4 promoter. Moreover, comparative genomics analysis reveals that a greater number of active CREs than active TREs are evolutionarily conserved between mice and primates, including humans. Taken together, our study demonstrates the reliability and robustness of ctSCAN-SMS screening to identify critical REs and investigate their roles in the regulation of transcriptional output of a target gene (in this case Oct4) in their native context.
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Affiliation(s)
- Matthew C Canver
- Division of Hematology/Oncology, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute (DFCI), Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Pratibha Tripathi
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Michael J Bullen
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Moshe Olshansky
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Computational Biology and Bioinformatics, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Yogesh Kumar
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Lee H Wong
- Department of Biochemistry and Molecular Biology, Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Stephen J Turner
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Samuel Lessard
- Research Center, Montreal Heart Institute, Montréal, Quebec, Canada; Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Luca Pinello
- Molecular Pathology and Cancer Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Stuart H Orkin
- Division of Hematology/Oncology, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute (DFCI), Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, USA; Howard Hughes Medical Institute, Boston, Massachusetts, USA.
| | - Partha Pratim Das
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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Rimmele P, Ling H, Lessard S, Moran K, Vieira B, Lin YD, Hong V, Reik A, Dang D, Huttner K, Hicks A. PF736 ZINC FINGER NUCLEASE-MEDIATED DISRUPTION OF THE BCL11A ERYTHROID ENHANCER IN PLERIXAFOR MOBILIZED CD34+ CELLS RESULTS IN ENRICHED BIALLELEIC EDITING AND ALLELE-ADDITIVE INCREASES IN FETAL HEMOGLOBIN. Hemasphere 2019. [DOI: 10.1097/01.hs9.0000561228.81599.cf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Lessard S, Beaudoin M, Orkin SH, Bauer DE, Lettre G. 14q32 and let-7 microRNAs regulate transcriptional networks in fetal and adult human erythroblasts. Hum Mol Genet 2019; 27:1411-1420. [PMID: 29432581 DOI: 10.1093/hmg/ddy051] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/05/2018] [Indexed: 12/29/2022] Open
Abstract
In humans, fetal erythropoiesis takes place in the liver whereas adult erythropoiesis occurs in the bone marrow. Fetal and adult erythroid cells are not only produced at different sites, but are also distinguished by their respective transcriptional program. In particular, whereas fetal erythroid cells express γ-globin chains to produce fetal hemoglobin (HbF), adult cells express β-globin chains to generate adult hemoglobin. Understanding the transcriptional regulation of the fetal-to-adult hemoglobin switch is clinically important as re-activation of HbF production in adult erythroid cells would represent a promising therapy for the hemoglobin disorders sickle cell disease and β-thalassemia. We used RNA-sequencing to measure global gene and microRNA (miRNA) expression in human erythroblasts derived ex vivo from fetal liver (n = 12 donors) and bone marrow (n = 12 donors) hematopoietic stem/progenitor cells. We identified 7829 transcripts and 402 miRNA that were differentially expressed (false discovery rate <5%). The miRNA expression patterns were replicated in an independent collection of human erythroblasts using a different technology. By combining gene and miRNA expression data, we developed transcriptional networks which show substantial differences between fetal and adult human erythroblasts. Our analyses highlighted the miRNAs at the imprinted 14q32 locus in fetal erythroblasts and the let-7 miRNA family in adult erythroblasts as key regulators of stage-specific erythroid transcriptional programs. Altogether, our results provide a comprehensive resource to prioritize genes that may modify clinical severity in red blood cell (RBC) disorders, or genes that might be implicated in erythropoiesis by genome-wide association studies of RBC traits.
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Affiliation(s)
- Samuel Lessard
- Montreal Heart Institute, Montréal, QC H1T 1C8, Canada.,Faculté de Médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | | | - Stuart H Orkin
- Division of Hematology/Oncology, Boston Children's Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.,Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Daniel E Bauer
- Division of Hematology/Oncology, Boston Children's Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Guillaume Lettre
- Montreal Heart Institute, Montréal, QC H1T 1C8, Canada.,Faculté de Médecine, Université de Montréal, Montréal, QC H3T 1J4, Canada
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Saber MG, Osman M, Patel D, Samani A, El-Fiky E, Alam MS, Shahriar KA, Xing Z, Jacques M, Dortschy B, Vall-Llosera G, Urban PJ, Cavaliere F, Lessard S, Plant DV. Demonstration of a 120° hybrid based simplified coherent receiver on SOI for high speed PON applications. Opt Express 2018; 26:31222-31232. [PMID: 30650711 DOI: 10.1364/oe.26.031222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate the first simplified coherent receiver using a 120° hybrid on silicon-on-insulator (SOI) for high speed PON applications. This coherent receiver integrates an inverse taper edge coupler for the received signal, a vertical grating coupler for the local oscillator input, a polarization splitter and rotator (PSR), a 120° hybrid based on a 3×3 multimode interference (MMI) coupler, and three germanium photodetectors. We achieved 25 Gbit/s two-level pulse amplitude modulation (PAM-2) transmission over 30 km standard single mode fiber (SMF) in the C-band without any digital signal processing (DSP) (e.g., pre-emphasis, pulse shaping, equalization, nonlinearity compensation) and dispersion compensation (e.g., optical or digital) either at the transmitter or at the receiver. The requirements for frequency and phase locking of the local oscillator (LO) were avoided due to the use of intensity modulated signals. Receiver sensitivities of -23.70 dBm, -20.30 dBm, and -15.10 dBm are achieved at a bit error rate (BER) below the hard-decision forward error correction (HD-FEC) threshold (i.e., 3.8 × 10-3) in back-to-back (B2B), after 21 km and 30 km, respectively. We also demonstrate 25 Gbit/s PAM-4 transmission achieving receiver sensitivities of -15.30 dBm, -13.90 dBm, and -9.50 dBm below the HD-FEC threshold in B2B, after 10.5 km and 21 km, respectively.
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Benard T, Parnell L, Lessard S, Fielding R, Rivas D. SHIFTS IN MICRORNA EXPRESSION PROFILES WITHIN SKELETAL MUSCLE AND ADIPOSE ACROSS THE LIFESPAN. Innov Aging 2018. [DOI: 10.1093/geroni/igy023.384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - L Parnell
- USDA Agricultural Research Service, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | | | - R Fielding
- Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
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8
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Raffield LM, Ulirsch JC, Naik RP, Lessard S, Handsaker RE, Jain D, Kang HM, Pankratz N, Auer PL, Bao EL, Smith JD, Lange LA, Lange EM, Li Y, Thornton TA, Young BA, Abecasis GR, Laurie CC, Nickerson DA, McCarroll SA, Correa A, Wilson JG, Lettre G, Sankaran VG, Reiner AP. Common α-globin variants modify hematologic and other clinical phenotypes in sickle cell trait and disease. PLoS Genet 2018; 14:e1007293. [PMID: 29590102 PMCID: PMC5891078 DOI: 10.1371/journal.pgen.1007293] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/09/2018] [Accepted: 03/06/2018] [Indexed: 11/18/2022] Open
Abstract
Co-inheritance of α-thalassemia has a significant protective effect on the severity of complications of sickle cell disease (SCD), including stroke. However, little information exists on the association and interactions for the common African ancestral α-thalassemia mutation (-α3.7 deletion) and β-globin traits (HbS trait [SCT] and HbC trait) on important clinical phenotypes such as red blood cell parameters, anemia, and chronic kidney disease (CKD). In a community-based cohort of 2,916 African Americans from the Jackson Heart Study, we confirmed the expected associations between SCT, HbC trait, and the -α3.7 deletion with lower mean corpuscular volume/mean corpuscular hemoglobin and higher red blood cell count and red cell distribution width. In addition to the recently recognized association of SCT with lower estimated glomerular filtration rate and glycated hemoglobin (HbA1c), we observed a novel association of the -α3.7 deletion with higher HbA1c levels. Co-inheritance of each additional copy of the -α3.7 deletion significantly lowered the risk of anemia and chronic kidney disease among individuals with SCT (P-interaction = 0.031 and 0.019, respectively). Furthermore, co-inheritance of a novel α-globin regulatory variant was associated with normalization of red cell parameters in individuals with the -α3.7 deletion and significantly negated the protective effect of α-thalassemia on stroke in 1,139 patients with sickle cell anemia from the Cooperative Study of Sickle Cell Disease (CSSCD) (P-interaction = 0.0049). Functional assays determined that rs11865131, located in the major alpha-globin enhancer MCS-R2, was the most likely causal variant. These findings suggest that common α- and β-globin variants interact to influence hematologic and clinical phenotypes in African Americans, with potential implications for risk-stratification and counseling of individuals with SCD and SCT.
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Affiliation(s)
- Laura M. Raffield
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Jacob C. Ulirsch
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Rakhi P. Naik
- Hematology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Samuel Lessard
- Department of Medicine, Université de Montréal, Montréal, Quebec, Canada
- Montreal Heart Institute, Montréal, Quebec, Canada
| | - Robert E. Handsaker
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Deepti Jain
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Hyun M. Kang
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Nathan Pankratz
- Department of Laboratory Medicine & Pathology, School of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Paul L. Auer
- Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Erik L. Bao
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Joshua D. Smith
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Leslie A. Lange
- Department of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Ethan M. Lange
- Department of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Yun Li
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Computer Science, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Timothy A. Thornton
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Bessie A. Young
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Seattle Epidemiologic Research and Information Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, United States of America
| | - Goncalo R. Abecasis
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Cathy C. Laurie
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Deborah A. Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Steven A. McCarroll
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Adolfo Correa
- Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - James G. Wilson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | | | - Guillaume Lettre
- Department of Medicine, Université de Montréal, Montréal, Quebec, Canada
- Montreal Heart Institute, Montréal, Quebec, Canada
| | - Vijay G. Sankaran
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- * E-mail: (APR); (VGS)
| | - Alex P. Reiner
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
- * E-mail: (APR); (VGS)
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Lessard S, Francioli L, Alfoldi J, Tardif JC, Ellinor PT, MacArthur DG, Lettre G, Orkin SH, Canver MC. Human genetic variation alters CRISPR-Cas9 on- and off-targeting specificity at therapeutically implicated loci. Proc Natl Acad Sci U S A 2017; 114:E11257-E11266. [PMID: 29229813 PMCID: PMC5748207 DOI: 10.1073/pnas.1714640114] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The CRISPR-Cas9 nuclease system holds enormous potential for therapeutic genome editing of a wide spectrum of diseases. Large efforts have been made to further understanding of on- and off-target activity to assist the design of CRISPR-based therapies with optimized efficacy and safety. However, current efforts have largely focused on the reference genome or the genome of cell lines to evaluate guide RNA (gRNA) efficiency, safety, and toxicity. Here, we examine the effect of human genetic variation on both on- and off-target specificity. Specifically, we utilize 7,444 whole-genome sequences to examine the effect of variants on the targeting specificity of ∼3,000 gRNAs across 30 therapeutically implicated loci. We demonstrate that human genetic variation can alter the off-target landscape genome-wide including creating and destroying protospacer adjacent motifs (PAMs). Furthermore, single-nucleotide polymorphisms (SNPs) and insertions/deletions (indels) can result in altered on-target sites and novel potent off-target sites, which can predispose patients to treatment failure and adverse effects, respectively; however, these events are rare. Taken together, these data highlight the importance of considering individual genomes for therapeutic genome-editing applications for the design and evaluation of CRISPR-based therapies to minimize risk of treatment failure and/or adverse outcomes.
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Affiliation(s)
- Samuel Lessard
- Research Center, Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Laurent Francioli
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142
| | - Jessica Alfoldi
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142
| | - Jean-Claude Tardif
- Research Center, Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Patrick T Ellinor
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA 02129
| | - Daniel G MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114
- Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142
| | - Guillaume Lettre
- Research Center, Montreal Heart Institute, Montréal, QC H1T 1C8, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Stuart H Orkin
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115;
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115
- Howard Hughes Medical Institute, Boston, MA 02115
| | - Matthew C Canver
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115;
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115
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10
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Lessard S, Gatof ES, Beaudoin M, Schupp PG, Sher F, Ali A, Prehar S, Kurita R, Nakamura Y, Baena E, Ledoux J, Oceandy D, Bauer DE, Lettre G. An erythroid-specific ATP2B4 enhancer mediates red blood cell hydration and malaria susceptibility. J Clin Invest 2017; 127:3065-3074. [PMID: 28714864 PMCID: PMC5531409 DOI: 10.1172/jci94378] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/01/2017] [Indexed: 12/12/2022] Open
Abstract
The lack of mechanistic explanations for many genotype-phenotype associations identified by GWAS precludes thorough assessment of their impact on human health. Here, we conducted an expression quantitative trait locus (eQTL) mapping analysis in erythroblasts and found erythroid-specific eQTLs for ATP2B4, the main calcium ATPase of red blood cells (rbc). The same SNPs were previously associated with mean corpuscular hemoglobin concentration (MCHC) and susceptibility to severe malaria infection. We showed that Atp2b4-/- mice demonstrate increased MCHC, confirming ATP2B4 as the causal gene at this GWAS locus. Using CRISPR-Cas9, we fine mapped the genetic signal to an erythroid-specific enhancer of ATP2B4. Erythroid cells with a deletion of the ATP2B4 enhancer had abnormally high intracellular calcium levels. These results illustrate the power of combined transcriptomic, epigenomic, and genome-editing approaches in characterizing noncoding regulatory elements in phenotype-relevant cells. Our study supports ATP2B4 as a potential target for modulating rbc hydration in erythroid disorders and malaria infection.
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Affiliation(s)
- Samuel Lessard
- Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Emily Stern Gatof
- Division of Hematology/Oncology, Boston Children’s Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
- Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Mélissa Beaudoin
- Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Patrick G. Schupp
- Division of Hematology/Oncology, Boston Children’s Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Falak Sher
- Division of Hematology/Oncology, Boston Children’s Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Adnan Ali
- Cancer Research UK Manchester Institute, and
| | - Sukhpal Prehar
- Division of Cardiovascular Sciences, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Ryo Kurita
- Cell Engineering Division, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan
| | - Yukio Nakamura
- Cell Engineering Division, RIKEN BioResource Center, Tsukuba, Ibaraki, Japan
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | | | - Jonathan Ledoux
- Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
| | - Delvac Oceandy
- Division of Cardiovascular Sciences, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Daniel E. Bauer
- Division of Hematology/Oncology, Boston Children’s Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Guillaume Lettre
- Montreal Heart Institute and Université de Montréal, Montréal, Québec, Canada
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11
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Lalonde S, Stone OA, Lessard S, Lavertu A, Desjardins J, Beaudoin M, Rivas M, Stainier DYR, Lettre G. Frameshift indels introduced by genome editing can lead to in-frame exon skipping. PLoS One 2017; 12:e0178700. [PMID: 28570605 PMCID: PMC5453576 DOI: 10.1371/journal.pone.0178700] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 05/17/2017] [Indexed: 12/31/2022] Open
Abstract
The introduction of frameshift indels by genome editing has emerged as a powerful technique to study the functions of uncharacterized genes in cell lines and model organisms. Such mutations should lead to mRNA degradation owing to nonsense-mediated mRNA decay or the production of severely truncated proteins. Here, we show that frameshift indels engineered by genome editing can also lead to skipping of “multiple of three nucleotides” exons. Such splicing events result in in-frame mRNA that may encode fully or partially functional proteins. We also characterize a segregating nonsense variant (rs2273865) located in a “multiple of three nucleotides” exon of LGALS8 that increases exon skipping in human erythroblast samples. Our results highlight the potentially frequent contribution of exonic splicing regulatory elements and are important for the interpretation of negative results in genome editing experiments. Moreover, they may contribute to a better annotation of loss-of-function mutations in the human genome.
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Affiliation(s)
| | - Oliver A. Stone
- Department of Biochemistry & Biophysics, UCSF, San Francisco, California, United States of America
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Samuel Lessard
- Montreal Heart Institute, Montreal, Quebec, Canada
- Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Adam Lavertu
- Department of Biomedical Data Science, Stanford University, Stanford, California, United States of America
| | | | | | - Manuel Rivas
- Department of Biomedical Data Science, Stanford University, Stanford, California, United States of America
| | - Didier Y. R. Stainier
- Department of Biochemistry & Biophysics, UCSF, San Francisco, California, United States of America
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Guillaume Lettre
- Montreal Heart Institute, Montreal, Quebec, Canada
- Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
- * E-mail:
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12
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Canver MC, Lessard S, Pinello L, Wu Y, Ilboudo Y, Stern EN, Needleman AJ, Galactéros F, Brugnara C, Kutlar A, McKenzie C, Reid M, Chen DD, Das PP, A Cole M, Zeng J, Kurita R, Nakamura Y, Yuan GC, Lettre G, Bauer DE, Orkin SH. Variant-aware saturating mutagenesis using multiple Cas9 nucleases identifies regulatory elements at trait-associated loci. Nat Genet 2017; 49:625-634. [PMID: 28218758 PMCID: PMC5374001 DOI: 10.1038/ng.3793] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/25/2017] [Indexed: 02/06/2023]
Abstract
Cas9-mediated, high-throughput, saturating in situ mutagenesis permits fine-mapping of function across genomic segments. Disease- and trait-associated variants from genome-wide association studies largely cluster in regulatory DNA. Here we demonstrate the use of multiple designer nucleases and variant-aware library design to interrogate trait-associated regulatory DNA at high resolution. We developed a computational tool for the creation of saturating mutagenesis libraries with single or combinatorial nucleases with incorporation of variants. We applied this methodology to the HBS1L-MYB intergenic region, a locus associated with red blood cell traits, including fetal hemoglobin levels. This approach identified putative regulatory elements that control MYB expression. Analysis of genomic copy number highlighted potential false positive regions, which emphasizes the importance of off-target analysis in design of saturating mutagenesis experiments. Taken together, these data establish a widely applicable high-throughput and high-resolution methodology to reliably identify minimal functional sequences within large regions of disease- and trait-associated DNA.
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Affiliation(s)
- Matthew C Canver
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Samuel Lessard
- Montreal Heart Institute, Université de Montréal, Montréal, Québec, Canada
| | - Luca Pinello
- Department of Molecular Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yuxuan Wu
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Yann Ilboudo
- Montreal Heart Institute, Université de Montréal, Montréal, Québec, Canada
| | - Emily N Stern
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Austen J Needleman
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Frédéric Galactéros
- Red Cell Genetic Disease Unit, Hôpital Henri-Mondor, Assistance Publique-Hôpitaux de Paris (AP-HP), UPeC, IMRB U955 Equipe no. 2, Créteil, France
| | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Abdullah Kutlar
- Department of Medicine, Sickle Cell Center, Augusta University, Augusta, Georgia, USA
| | - Colin McKenzie
- The Caribbean Institute for Health Research, University of the West Indies, Mona, Kingston, Jamaica
| | - Marvin Reid
- The Caribbean Institute for Health Research, University of the West Indies, Mona, Kingston, Jamaica
| | - Diane D Chen
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Partha Pratim Das
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Mitchel A Cole
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Jing Zeng
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Ryo Kurita
- Department of Research and Development, Central Blood Institute, Japanese Red Cross Society, Tokyo, Japan
| | - Yukio Nakamura
- Cell Engineering Division, RIKEN BioResource Center, Tsukuba, Japan.,Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Guo-Cheng Yuan
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Guillaume Lettre
- Montreal Heart Institute, Université de Montréal, Montréal, Québec, Canada
| | - Daniel E Bauer
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Stuart H Orkin
- Division of Hematology/Oncology, Boston Children's Hospital; Department of Pediatric Oncology, Dana-Farber Cancer Institute; Harvard Stem Cell Institute; and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Boston, Massachusetts, USA
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13
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Nguyen A, Mamarbachi M, Turcot V, Lessard S, Yu C, Luo X, Lalongé J, Hayami D, Gayda M, Juneau M, Thorin-Trescases N, Lettre G, Nigam A, Thorin E. Lower Methylation of the ANGPTL2 Gene in Leukocytes from Post-Acute Coronary Syndrome Patients. PLoS One 2016; 11:e0153920. [PMID: 27101308 PMCID: PMC4839636 DOI: 10.1371/journal.pone.0153920] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/06/2016] [Indexed: 02/08/2023] Open
Abstract
DNA methylation is believed to regulate gene expression during adulthood in response to the constant changes in environment. The methylome is therefore proposed to be a biomarker of health through age. ANGPTL2 is a circulating pro-inflammatory protein that increases with age and prematurely in patients with coronary artery diseases; integrating the methylation pattern of the promoter may help differentiate age- vs. disease-related change in its expression. We believe that in a pro-inflammatory environment, ANGPTL2 is differentially methylated, regulating ANGPTL2 expression. To test this hypothesis we investigated the changes in promoter methylation of ANGPTL2 gene in leukocytes from patients suffering from post-acute coronary syndrome (ACS). DNA was extracted from circulating leukocytes of post-ACS patients with cardiovascular risk factors and from healthy young and age-matched controls. Methylation sites (CpGs) found in the ANGPTL2 gene were targeted for specific DNA methylation quantification. The functionality of ANGPTL2 methylation was assessed by an in vitro luciferase assay. In post-ACS patients, C-reactive protein and ANGPTL2 circulating levels increased significantly when compared to healthy controls. Decreased methylation of specific CpGs were found in the promoter of ANGPTL2 and allowed to discriminate age vs. disease associated methylation. In vitro DNA methylation of specific CpG lead to inhibition of ANGPTL2 promoter activity. Reduced leukocyte DNA methylation in the promoter region of ANGPTL2 is associated with the pro-inflammatory environment that characterizes patients with post-ACS differently from age-matched healthy controls. Methylation of different CpGs in ANGPTL2 gene may prove to be a reliable biomarker of coronary disease.
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Affiliation(s)
- Albert Nguyen
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Maya Mamarbachi
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
| | - Valérie Turcot
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
| | - Samuel Lessard
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
| | - Carol Yu
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Xiaoyan Luo
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
| | - Julie Lalongé
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Cardiac Rehabilitation and Prevention Center (EPIC) of the Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Doug Hayami
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Cardiac Rehabilitation and Prevention Center (EPIC) of the Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Mathieu Gayda
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Cardiac Rehabilitation and Prevention Center (EPIC) of the Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Martin Juneau
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Cardiac Rehabilitation and Prevention Center (EPIC) of the Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | | | - Guillaume Lettre
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Anil Nigam
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Cardiac Rehabilitation and Prevention Center (EPIC) of the Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
- * E-mail: (AN); (ET)
| | - Eric Thorin
- Montreal Heart Institute, Research Center, Université de Montréal, Montreal, Quebec, Canada
- Department of Surgery, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
- * E-mail: (AN); (ET)
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14
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Lessard S, Manning AK, Low-Kam C, Auer PL, Giri A, Graff M, Schurmann C, Yaghootkar H, Luan J, Esko T, Karaderi T, Bottinger EP, Lu Y, Carlson C, Caulfield M, Dubé MP, Jackson RD, Kooperberg C, McKnight B, Mongrain I, Peters U, Reiner AP, Rhainds D, Sotoodehnia N, Hirschhorn JN, Scott RA, Munroe PB, Frayling TM, Loos RJF, North KE, Edwards TL, Tardif JC, Lindgren CM, Lettre G. Testing the role of predicted gene knockouts in human anthropometric trait variation. Hum Mol Genet 2016; 25:2082-2092. [PMID: 26908616 PMCID: PMC5062577 DOI: 10.1093/hmg/ddw055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/15/2016] [Indexed: 11/12/2022] Open
Abstract
Although the role of complete gene inactivation by two loss-of-function mutations inherited in trans is well-established in recessive Mendelian diseases, we have not yet explored how such gene knockouts (KOs) could influence complex human phenotypes. Here, we developed a statistical framework to test the association between gene KOs and quantitative human traits. Our method is flexible, publicly available, and compatible with common genotype format files (e.g. PLINK and vcf). We characterized gene KOs in 4498 participants from the NHLBI Exome Sequence Project (ESP) sequenced at high coverage (>100×), 1976 French Canadians from the Montreal Heart Institute Biobank sequenced at low coverage (5.7×), and >100 000 participants from the Genetic Investigation of ANthropometric Traits (GIANT) Consortium genotyped on an exome array. We tested associations between gene KOs and three anthropometric traits: body mass index (BMI), height and BMI-adjusted waist-to-hip ratio (WHR). Despite our large sample size and multiple datasets available, we could not detect robust associations between specific gene KOs and quantitative anthropometric traits. Our results highlight several limitations and challenges for future gene KO studies in humans, in particular when there is no prior knowledge on the phenotypes that might be affected by the tested gene KOs. They also suggest that gene KOs identified with current DNA sequencing methodologies probably do not strongly influence normal variation in BMI, height, and WHR in the general human population.
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Affiliation(s)
- Samuel Lessard
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Alisa K Manning
- Medical and Population Genetics Program, Broad Institute, Cambridge, MA 02142, USA Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA Department of Medicine and
| | - Cécile Low-Kam
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Paul L Auer
- School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, WI 53201-0413, USA
| | - Ayush Giri
- Division of Epidemiology, Institute for Medicine and Public Health and
| | - Mariaelisa Graff
- University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC 27599, USA
| | - Claudia Schurmann
- The Charles Bronfman Institute for Personalized Medicine and The Mindich Child Health and Development Institute, the Genetics of Obesity and Related Metabolic Traits Program, The Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hanieh Yaghootkar
- Genetics of Complex Traits, University of Exeter Medical School, University of Exeter, Exeter EX2 5DW, UK
| | - Jian'an Luan
- Medical Research Council Epidemiology Unit, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Tonu Esko
- Medical and Population Genetics Program, Broad Institute, Cambridge, MA 02142, USA Estonian Genome Center, University of Tartu, Tartu, Estonia Division of Endocrinology, Genetics and Basic and Translational Obesity Research, Children's Hospital Boston, Boston, MA 02115, USA
| | - Tugce Karaderi
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | | | | | | | | | | | - Yingchang Lu
- The Charles Bronfman Institute for Personalized Medicine and
| | - Chris Carlson
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Mark Caulfield
- Clinical Pharmacology, William Harvey Research Institute and NIHR Barts Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Marie-Pierre Dubé
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Rebecca D Jackson
- Division of Endocrinology, Diabetes and Metabolism, Ohio State University, Columbus, OH 43210, USA
| | - Charles Kooperberg
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Barbara McKnight
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Ian Mongrain
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada
| | - Ulrike Peters
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Alex P Reiner
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - David Rhainds
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada
| | - Nona Sotoodehnia
- Division of Cardiology, Cardiovascular Health Research Unit, University of Washington, Seattle, WA 98195-6422, USA
| | - Joel N Hirschhorn
- Medical and Population Genetics Program, Broad Institute, Cambridge, MA 02142, USA Department of Genetics, Harvard Medical School, Boston, MA 02115, USA Division of Endocrinology, Genetics and Basic and Translational Obesity Research, Children's Hospital Boston, Boston, MA 02115, USA
| | - Robert A Scott
- Medical Research Council Epidemiology Unit, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Patricia B Munroe
- Clinical Pharmacology, William Harvey Research Institute and NIHR Barts Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Timothy M Frayling
- Genetics of Complex Traits, University of Exeter Medical School, University of Exeter, Exeter EX2 5DW, UK
| | - Ruth J F Loos
- The Charles Bronfman Institute for Personalized Medicine and The Mindich Child Health and Development Institute, the Genetics of Obesity and Related Metabolic Traits Program, The Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kari E North
- University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC 27599, USA
| | - Todd L Edwards
- Division of Epidemiology, Institute for Medicine and Public Health and Department of Medicine, Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37203, USA
| | - Jean-Claude Tardif
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Cecilia M Lindgren
- Medical and Population Genetics Program, Broad Institute, Cambridge, MA 02142, USA Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK The Big Data Institute, University of Oxford, Oxford, UK
| | - Guillaume Lettre
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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15
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Lessard S, Beaudoin M, Benkirane K, Lettre G. Comparison of DNA methylation profiles in human fetal and adult red blood cell progenitors. Genome Med 2015; 7:1. [PMID: 25606059 PMCID: PMC4298057 DOI: 10.1186/s13073-014-0122-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/09/2014] [Indexed: 11/21/2022] Open
Abstract
Background DNA methylation is an epigenetic modification that plays an important role during mammalian development. Around birth in humans, the main site of red blood cell production moves from the fetal liver to the bone marrow. DNA methylation changes at the β-globin locus and a switch from fetal to adult hemoglobin production characterize this transition. Understanding this globin switch may improve the treatment of patients with sickle cell disease and β-thalassemia, two of the most common Mendelian diseases in the world. The goal of our study was to describe and compare the genome-wide patterns of DNA methylation in fetal and adult human erythroblasts. Methods We used the Illumina HumanMethylation 450 k BeadChip to measure DNA methylation at 402,819 CpGs in ex vivo-differentiated erythroblasts from 12 fetal liver and 12 bone marrow CD34+ donors. Results We identified 5,937 differentially methylated CpGs that overlap with erythroid enhancers and binding sites for erythropoiesis-related transcription factors. Combining this information with genome-wide association study results, we show that erythroid enhancers define particularly promising genomic regions to identify new genetic variants associated with fetal hemoglobin (HbF) levels in humans. Many differentially methylated CpGs are located near genes with unanticipated roles in red blood cell differentiation and proliferation. For some of these new candidate genes, we confirm the correlation between DNA methylation and gene expression levels in red blood cell progenitors. We also provide evidence that DNA methylation and genetic variation at the β-globin locus independently control globin gene expression in adult erythroblasts. Conclusions Our DNA methylome maps confirm the widespread dynamic changes in DNA methylation that occur during human erythropoiesis. These changes tend to happen near erythroid enhancers, further highlighting their importance in erythroid regulation and HbF production. Finally, DNA methylation may act independently of the transcription factor BCL11A to repress fetal hemoglobin production. This provides cues on strategies to more efficiently re-activate HbF production in sickle cell disease and β-thalassemia patients. Electronic supplementary material The online version of this article (doi:10.1186/s13073-014-0122-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samuel Lessard
- Montreal Heart Institute, 5000 Bélanger Street, Montréal, Québec H1T 1C8 Canada ; Faculté de Médecine, Université de Montréal, 2900 Boul. Édouard-Montpetit, Montréal, Québec H3T 1J4 Canada
| | - Mélissa Beaudoin
- Montreal Heart Institute, 5000 Bélanger Street, Montréal, Québec H1T 1C8 Canada
| | - Karim Benkirane
- Hôpital Maisonneuve-Rosemont, 5415 Boul. de l'Assomption, Montréal, Québec H1T 2M4 Canada
| | - Guillaume Lettre
- Montreal Heart Institute, 5000 Bélanger Street, Montréal, Québec H1T 1C8 Canada ; Faculté de Médecine, Université de Montréal, 2900 Boul. Édouard-Montpetit, Montréal, Québec H3T 1J4 Canada
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16
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Bauer DE, Kamran SC, Lessard S, Xu J, Fujiwara Y, Lin C, Shao Z, Canver MC, Smith EC, Pinello L, Sabo PJ, Vierstra J, Voit RA, Yuan GC, Porteus MH, Stamatoyannopoulos JA, Lettre G, Orkin SH. An erythroid enhancer of BCL11A subject to genetic variation determines fetal hemoglobin level. Science 2013; 342:253-7. [PMID: 24115442 PMCID: PMC4018826 DOI: 10.1126/science.1242088] [Citation(s) in RCA: 448] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Genome-wide association studies (GWASs) have ascertained numerous trait-associated common genetic variants, frequently localized to regulatory DNA. We found that common genetic variation at BCL11A associated with fetal hemoglobin (HbF) level lies in noncoding sequences decorated by an erythroid enhancer chromatin signature. Fine-mapping uncovers a motif-disrupting common variant associated with reduced transcription factor (TF) binding, modestly diminished BCL11A expression, and elevated HbF. The surrounding sequences function in vivo as a developmental stage-specific, lineage-restricted enhancer. Genome engineering reveals the enhancer is required in erythroid but not B-lymphoid cells for BCL11A expression. These findings illustrate how GWASs may expose functional variants of modest impact within causal elements essential for appropriate gene expression. We propose the GWAS-marked BCL11A enhancer represents an attractive target for therapeutic genome engineering for the β-hemoglobinopathies.
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Affiliation(s)
- Daniel E. Bauer
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115
- Harvard Medical School, Boston, MA, 02115
| | - Sophia C. Kamran
- Harvard Medical School, Boston, MA, 02115
- Howard Hughes Medical Institute, Boston, MA, 02115
| | - Samuel Lessard
- Montreal Heart Institute and Université Montréal, Montreal, Quebec, H1T 1C8, Canada
| | - Jian Xu
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
- Harvard Medical School, Boston, MA, 02115
| | - Yuko Fujiwara
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
| | - Carrie Lin
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
| | - Zhen Shao
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
| | | | - Elenoe C. Smith
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
| | - Luca Pinello
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA, 02115
| | - Peter J. Sabo
- Departments of Genome Sciences and Medicine, University of Washington, Seattle, WA, 98195
| | - Jeff Vierstra
- Departments of Genome Sciences and Medicine, University of Washington, Seattle, WA, 98195
| | - Richard A. Voit
- Department of Pediatrics, Stanford University, Palo Alto, CA, 94304
| | - Guo-Cheng Yuan
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA, 02115
- Harvard School of Public Health, Boston, MA, 02115
| | | | | | - Guillaume Lettre
- Montreal Heart Institute and Université Montréal, Montreal, Quebec, H1T 1C8, Canada
| | - Stuart H. Orkin
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, MA, 02115
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115
- Harvard Medical School, Boston, MA, 02115
- Howard Hughes Medical Institute, Boston, MA, 02115
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Chue P, Malla A, Bouchard RH, Lessard S, Ganesan S, Stip E, Johnson S, Chen E, Ahn YM, Kim YS, Robinson G, Schweikert C, Gendron A, Eriksson H. The long-term clinical benefit and effectiveness of switching to once-daily quetiapine extended release in patients with schizophrenia. Curr Med Res Opin 2013; 29:227-39. [PMID: 23281876 DOI: 10.1185/03007995.2012.762903] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To evaluate the long-term clinical benefit and effectiveness of switching to once-daily quetiapine extended release (XR) from an oral antipsychotic in patients with schizophrenia. Reasons for switching included insufficient efficacy, tolerability, and/or non-acceptability. The primary endpoint was the percentage of patients achieving an improvement in Clinical Global Impression - Clinical Benefit (CGI-CB) scale scores. RESEARCH DESIGN AND METHODS A 24-week, international, multicentre, open-label, prospective study ( www.clinicaltrials.gov : NCT00640601). After a 7-14 day enrolment period (depending whether prior antipsychotic mono- or combination therapy), all patients received quetiapine XR 300 mg once daily (day 1), 600 mg/day (day 2), 600-800 mg/day (day 3) and 400-800 mg/day thereafter, with down-titration and discontinuation of prior antipsychotic by day 4. RESULTS A total of 62% of patients completed the study and 56.9% (LOCF, ITT) achieved a significant improvement in CGI-CB (95% CI [0.51, 0.63]; p = 0.02). Switches due to insufficient efficacy showed a significant improvement (60%, 95% CI [0.51, 0.68]; p = 0.02), compared to 54.4% ([0.44, 0.64]; p = 0.38) and 52.4% ([0.36, 0.68]; p = 0.76) of switches due to insufficient tolerability and non-acceptability respectively (both p = ns). Patients previously on olanzapine and quetiapine IR showed a significant improvement in CGI-CB (62.6% [p = 0.02] and 61.2% [p = 0.04], respectively). Somnolence (18.0%) and dizziness (14.6%) were the main adverse events. Anticholinergic use decreased from 7.1 to 2.7%. Overall mean weight gain was 0.4 kg; 12.9% of patients experienced a weight gain of ≥7% and 15% experienced a clinically relevant shift in triglycerides from baseline. CONCLUSIONS A majority of patients switched from other antipsychotics to quetiapine XR experienced clinical benefit. This was supported by all other efficacy outcomes regardless of the reason for switching. Safety data confirmed quetiapine XR was safe and well tolerated. The open-label design and lack of a placebo group represent limitations.
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Affiliation(s)
- P Chue
- Department of Psychiatry, Faculty of Medicine, University of Alberta, 9942-108 Street, Edmonton, Alberta T5K 2J5, Canada.
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Katzman MA, Vermani M, Jacobs L, Marcus M, Kong B, Lessard S, Galarraga W, Struzik L, Gendron A. Quetiapine as an adjunctive pharmacotherapy for the treatment of non-remitting generalized anxiety disorder: a flexible-dose, open-label pilot trial. J Anxiety Disord 2008; 22:1480-6. [PMID: 18455360 DOI: 10.1016/j.janxdis.2008.03.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Revised: 02/27/2008] [Accepted: 03/05/2008] [Indexed: 11/17/2022]
Abstract
BACKGROUND Generalized anxiety disorder (GAD) is a chronic disorder associated with significant morbidity and disability. Traditional therapies are associated with poor levels of remission, and often result in troublesome side effects. METHODS This was a 12-week, open-label, flexible-dose study to assess the efficacy and tolerability of quetiapine as an adjunctive treatment to traditional medication. 40 outpatients with GAD who had not achieved remission following at least 8 weeks of an adequate dose of traditional therapy were enrolled. The primary endpoint was the mean change from pre-treatment to week 12 in the Hamilton Anxiety Rating Scale (HAM-A) total scores. Secondary endpoints included: the proportion of patients achieving remission (HAM-A total score of < or =10 at week 12), Clinical Global Impressions-Severity of Illness (CGI-S), Clinical Global Impressions-Global Improvement (CGI-I), Pittsburgh Sleep Quality Index (PSQI) and Penn State Worry Questionnaire (PSWQ). RESULTS Adjunctive quetiapine (mean dose 386mg/day at week 12) significantly reduced the HAM-A total scores from pre-treatment (29.8+/-9.0) to week 12 (9.0+/-10.2) (-20.6; p<0.001). The HAM-A remission rate was 72.1% at week 12. Adjunctive quetiapine resulted in a significant reduction in all efficacy measures by study end. Quetiapine was well tolerated: the most common adverse event (AE) was sedation, with no incidence of serious AEs and no clinically significant changes in vital signs, weight (mean gain 0.5kg at week 12) or laboratory assessments. CONCLUSION The results of this small pilot trial suggest that quetiapine adjunctive to traditional therapy may be a useful treatment in patients with GAD or treatment-resistant GAD, and warrant further investigation.
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Affiliation(s)
- M A Katzman
- START Clinic for Mood and Anxiety Disorders, Canada.
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Hawke TJ, Lessard S, Vickery L, Lipskie SL, Lindinger MI. Ouabain stimulates unidirectional and net potassium efflux in resting mammalian skeletal muscle. Can J Physiol Pharmacol 2001; 79:932-41. [PMID: 11760095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The present study compared ouabain-sensitive unidirectional K+ flux into (JinK) and out of (JoutK) perfused rat hindlimb skeletal muscle in situ and mouse flexor digitorum brevis (FDB) in vitro. In situ, 5 mM ouabain inhibited 54 +/- 4% of the total JinK in 28 +/- 1 min, and increased the net and unidirectional efflux of K+ within 4 min. In contrast, 1.8 mM ouabain inhibited 40 +/- 8% of the total JinK in 38 +/- 2 min, but did not significantly affect JoutK. In vitro, 1.8 and 0.2 mM ouabain decreased JinK to a greater extent (83 +/- 5%) than in situ, but did not significantly affect 42K loss rate compared with controls. The increase in unidirectional K+ efflux (JoutK) with 5 mM ouabain in situ was attributed to increased K+ efflux through cation channels, since addition of barium (1 mM) to ouabain-perfused muscles returned JoutK to baseline values within 12 min. Perfusion with 5 mM ouabain plus 2 mM tetracaine for 30 min decreased JinK 46 +/- 9% (0.30 +/- 0.03 to 0.16 +/- 0.02 micromol x min(-1) x g(-1)), however tetracaine was unable to abolish the ouabain-induced increase in unidirectional K+ efflux. In both rat hindlimb and mouse FDB, tetracaine had no effect on JoutK. Perfusion of hindlimb muscle with 0.1 mM tetrodotoxin (TTX, a Na+ channel blocker) decreased JinK by 15 +/- 1%, but had no effect on JoutK; subsequent addition of ouabain (5 mM) decreased JinK a further 32 +/- 2%. The ouabain-induced increase in unidirectional K+ efflux did not occur when TTX was perfused prior to and during perfusion with 5 mM ouabain. We conclude that 5 mM ouabain increases the unidirectional efflux of K+ from skeletal muscle through a barium and TTX-sensitive pathway, suggestive of voltage sensitive Na+ channels, in addition to inhibiting Na+/K+-ATPase activity.
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Affiliation(s)
- T J Hawke
- Department of Human Biology and Nutritional Sciences, University of Guelph, ON, Canada.
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20
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Lessard S. Busting our mental blocks on drugs and crime. Wash Mon 2001; 3:6-18. [PMID: 11636868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Abstract
We investigate the equilibrium structure for an evolutionary genetic model in discrete time involving two monoecious populations subject to intraspecific and interspecific random pairwise interactions. A characterization for local stability of an equilibrium is found, related to the proximity of this equilibrium with evolutionarily stable strategies (ESS). This extends to a multi-population framework a principle initially proposed for single populations, which states that the mean population strategy at a locally stable equilibrium is as close as possible to an ESS.
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Affiliation(s)
- M Lemire
- Département de Mathématiques et de Statistique, Université de Montréal, Québec, Canada
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22
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Lessard S. William D. Hamilton: a tribute. Theor Popul Biol 2001; 59:7-9. [PMID: 11243922 DOI: 10.1006/tpbi.2000.1502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- S Lessard
- Département de Mathématiques et de Statistique, Université de Montréal, Succursale Centre-ville, Montréal, Québec, H3C 3J7, Canada
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Abstract
In this paper, we develop a general method to determine evolutionary equilibrium sex ratios and to check evolutionary stability, continuous stability and invadability in exact genetic models with or without dominance. This method is then applied to three kinds of models for structured populations: the first one concerns Hamilton's LMC model, except that only a fraction beta of female offspring mate with male offspring born in the same colonies, while a fraction 1-beta mate with male offspring chosen at random within the whole population; in the second model, it is assumed that partial dispersal of inseminated females occurs after mating; in the third model, partial dispersal of male and female offspring occurs before mating. In the first model, the effect of population regulation is studied while, in the other models, two kinds of dispersal are considered: proportional and uniform.
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Affiliation(s)
- J Courteau
- Département de mathématiques et de statistique, Université de Montréal, Succursale Centre-ville, Montréal, H3C 3J7, Canada
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Abstract
Following Ewens' interpretation about Fisher's fundamental theorem of natural selection, the matrix game model for diploid populations undergoing non-overlapping, discrete generations is investigated. The total genetic variance is decomposed and it is shown that the partial change in the mean fitness, which is equal to the additive genetic variance over the mean fitness, can be thought of as a change due only to the partial changes in the phenotypic frequencies.
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Affiliation(s)
- T Yi
- Département de Mathématiques et de Statistique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
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Mahdi S, Lessard S. Variability in centred house-of-cards mutation models. IMA J Math Appl Med Biol 2000; 17:185-200. [PMID: 11103717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Convergence of variability in phenotypic models with balance between selection and mutation is analysed. The mutation assumed occurs with weak probability and brings down the evolutionary process built up by selection around the mean in the population. Gaussian approximations are used.
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Affiliation(s)
- S Mahdi
- Department of Computer Science, Mathematics and Physics, University of the West Indies, Barbados, West Indies.
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Abstract
We undertake a detailed study of the one-locus two-allele partial selfing selection model. We show that a polymorphic equilibrium can exist only in the cases of overdominance and underdominance and only for a certain range of selfing rates. Furthermore, when it exists, we show that the polymorphic equilibrium is unique. The local stability of the polymorphic equilibrium is investigated and exact analytical conditions are presented. We also carry out an analysis of local stability of the fixation states and then conclude that only overdominance can maintain polymorphism in the population. When the linear local analysis is inconclusive, a quadratic analysis is performed. For some sets of selective values, we demonstrate global convergence. Finally, we compare and discuss results under the partial selfing model and the random mating model.
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Affiliation(s)
- G Rocheleau
- Département de mathématiques et de statistique, Université de Montréal, Québec, Canada
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27
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Abstract
In this paper, a sex-dependent matrix game haploid model is investigated. For this model, since the phenotypes of female and male individuals are determined by alleles located at a single locus and are sex dependent, any given genotype corresponds to a strategy pair. Thus, a strategy pair is an ESS if and only if the allele corresponding to this strategy pair cannot be invaded by any mutant allele. We show that an ESS equilibrium must be locally asymptotically stable if it exists.
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Affiliation(s)
- T Yi
- Département de Mathématiques et de Statistique, Université de Montréal, Québec, Canada
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28
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Abstract
LMC (local mate competition) was first introduced by W. D. Hamilton to explain extraordinary female-biased sex ratios observed in a variety of insects and mites. In the original model, the population is subdivided into an infinite number of colonies founded by a fixed number of inseminated females producing the same very large number of offspring. The male offspring compete within the colonies to inseminate the female offspring and then these disperse at random to found new colonies. An unbeatable sex ratio strategy is found to be female-biased. In this paper, the effects of having colonies of random size and foundresses producing a random finite number of offspring are considered. The exact evolutionarily stable strategy (ESS) sex ratio is deduced and comparisons with previous approximate or numerical results are made. As the mean or the variance of brood size increases, the ESS sex ratio becomes more female-biased. An increase in the variance of colony size increases the ESS proportion of males when the mean brood size and colony size are both small, but decreases this proportion when the mean brood size or the mean colony size is large.
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Affiliation(s)
- J Courteau
- Département de mathématiques et de statistique, Université de Montréal, Succursale Centre-ville, Montréal, H3C 3J7, Canada
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29
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Abstract
W. J. Ewens, following G. R. Price, has stressed that Fisher's fundamental theorem of natural selection about the increase in mean fitness is of general validity without any restrictive assumptions on the mating system, the fitness parameters, or the numbers of loci and alleles involved, but that it concerns only a partial change in mean fitness. This partial change is obtained by replacing the actual genotypic fitnesses by the corresponding additive genetic values and by keeping these values fixed in the change of the mean with respect to changes in genotype frequencies. We propose an alternate interpretation for this partial change which uses partial changes in genotype frequencies directly consequent on changes in gene frequencies, the fitness parameters being kept constant. We argue that this interpretation agrees more closely with Fisher's own explanations. Moreover, this approach leads to a decomposition for the total change in mean fitness which explains, unifies, and extends previous decompositions. We consider a wide range of models, from discrete-time selection models with nonoverlapping generations to continuous-time models with overlapping generations and age effects on viability and fecundity, which is the original framework for Fisher's fundamental theorem.
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Affiliation(s)
- S Lessard
- Département de mathématiques et de statistique, Université de Montréal, Succursale Centre-Ville, Montréal, Québec, H3C 3J7, Canada.
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Abstract
We show that an optimal migration rate may not exist in a population distributed over an infinite number of individual living sites if empty sites occur. This is the case when the mean number of offspring per individual mu is finite. We make the assumption of uniform migration to other sites whose rate is determined by the parent's genotype or the offspring's genotype at a single locus in a diploid hermaphrodite population undergoing random mating. In both cases, for mu small enough, any population at fixation would go to extinction. Moreover, in the latter case, for intermediate values of mu, the only fixation state that could resist the invasion of any mutant would lead the population to extinction. These are the two conditions for the non-existence of an optimal migration rate. They become less stringent as the cost for migration expressed by a coefficient of selection 1-beta becomes larger, that is closer to 1. The results are obtained assuming that the allele at fixation is either nondominant or dominant. Although the optimal migration rate is the same in both cases when it exists, the optimality properties may differ.
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Affiliation(s)
- M Lemire
- Département de mathématiques et de statistique, Université de Montréal, Québec, Canada
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Johansen H, Chagani K, Lessard S, Nair C. Person-based information from Canadian hospital discharge data. Leadersh Health Serv 1996; 5:27-32. [PMID: 10161456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Statistics summarizing Canadians' use of hospital services are usually based on simple discharge totals, without any attempt to distinguish which discharges may have belonged to the same person. This leads to a distorted view of the prevalence of illness and the resources required to serve each patient. Statistics based on the number of people going to hospital shed new light on the demand for resources by various groups, now and in the future.
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Abstract
We correct an equation characterizing the additive allelic effects on fitness determined at many loci without the assumption of random mating given in Ewens (1989, 1992) and we show that the additive genetic variance in fitness divided by the mean fitness is equal to a partial change in the mean fitness from one generation to the next as stated in Ewens (1989).
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Affiliation(s)
- A M Castilloux
- Département de mathématiques et de statistique, Université de Montréal, Québec, Canada
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33
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Abstract
We show that the Fundamental Theorem of Natural Selection in Ewens' sense is valid in the case of fertility selection: the additive genetic variance in fertility divided by the mean fertility is exactly equal to the partial change in the mean fertility from the current generation to the next. This partial change is the increase in the mean additive value caused by frequency changes from on generation to the next. This partial change is the increase in the mean additive value caused by frequency changes from one generation to the next but keeping unchanged the additive values. The only hypothesis on mating is that it does not affect the allelic frequencies in the sense that these are the same before and after mating in the parental generation, which occurs for a wide range of mating patterns going from random mating to several regular systems of inbreeding and cases of assortative mating. The fertility of couples is determined by the genes at an arbitrary number of loci, and the additive (average) allelic allelic effects are defined by a linear system of equations, which is used to extend Ewens' optimality principle to the case of fertility selection.
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Affiliation(s)
- S Lessard
- Département de Mathématiques et de Statistique, Université de Montréal, Québec, Canada
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35
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Abstract
Relatedness arising in kin selection theory is measured by a variable taking as values two pedigree indices in populations with inbreeding when selection is weak. This variable reduces to a single pedigree index when inbreeding is caused by partial selfing or partial sib-mating. General inclusive fitness formulations of kin selection models based on such a variable of relatedness are proposed.
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Affiliation(s)
- S Lessard
- Département de Mathématiques et de Statistique, Université de Montréal, Québec, Canada
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Stene JM, Karlin S, Lessard S. Theoretical Studies on Sex Ratio Evolution. Biometrics 1989. [DOI: 10.2307/2531516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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37
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Abstract
The equilibrium configurations for a two-locus multialle model of sex-linked meiotic drive are studied with regard to the recombination fraction:limit cycles can occur in the case of small recombination while stable equilibrium points associated with linkage equilibrium can exist for an intermediate range of recombination values depending on the equilibrium sex ratio, linkage disequilibrium at nearby equilibrium points taking turn with loser linkage. The evolutionary dynamics in two-locus sex-ratio distortion systems is enlightened: while equilibria with a sex ratio closer to 1/2 are more likely to be stable with respect to perturbations on the frequencies of sex-ratio distorters that are represented at equilibrium, such equilibria are also more vulnerable to the invasion of mutant distorters when there is some degree of linkage with the sex-determining locus. For X-linked multimodifier systems of sex-ratio distortion, differential fertilities and viabilities are incorporated and a maximum principle is suggested.
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Abstract
The evolutionary dynamics in general two-sex two-phenotype frequency-dependent selection models are studied with respect to underlying multi-allele one-locus genetic systems. Two classes of equilibria come into play: genotypic equilibria, with equilibrium allelic frequencies independent of the phenotype, and phenotypic equilibria, which are characterized by equal mean phenotypic fitnesses. The exact conditions for genotypic equilibria to exist and be stable and for phenotypic equilibria to exist and be evolutionarily attractive are examined. Using adequate definitions of mean fitnesses in general contexts of frequency-dependent selection in dioecious populations, we show that two phenotypes, when they can coexist in the population, tend to balance their fitnesses as far as is allowed by the genetic system as more alleles responsible for phenotype determination are introduced into the population.
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Karlin S, Lessard S. On the optimal sex-ratio: a stability analysis based on a characterization for one-locus multiallele viability models. J Math Biol 1984; 20:15-38. [PMID: 6491543 DOI: 10.1007/bf00275859] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Theoretical one-locus multiallele sex-determination models are found to admit even sex ratio equilibrium surfaces besides the equilibria for corresponding one-locus multiallele viability models. Both types of equilibria can be defined in terms of a single spectral radius function, the former corresponding to level surfaces and the latter to critical points. The stable equilibria in the corresponding viability models are associated with the local maxima, and the equilibrium structures for the sex-determination models can be fully described. Several optimality properties of the even-sex-ratio equilibrium surfaces can be deduced.
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40
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Abstract
General frequency-dependent selection models based on two phenotypic classes are analyzed with underlying one-locus multiallele phenotypic determination systems in diploid populations. It is proved that the mean phenotypic fitnesses tend to equality over discrete generations and genetic mutations if a phenotypic polymorphism is to be maintained. The exact conditions are examined. The present results are valid for a wide class of models whenever random groupings or assortative patterns based on phenotype and affecting fitness, linearly or not, are independent of sex, mating preferences, or kinship. They can also be applied to two-sex haploid models.
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Abstract
The equilibrium structures for various multiallele sex-determining genetic models of panmictic populations with sex expression depending on the genotypes of either the zygote or a parent are described. Even-sex-ratio equilibrium surfaces can exist apart from equilibrium points having coincident male and female allelic frequency sets. The latter (symmetric) equilibrium states entail biased sex ratios. A stable symmetric equilibrium and an even-sex-ratio equilibrium segregating the same alleles cannot coexist. The tendency to evolve toward an even-sex ratio is embodied by the following optimality property: starting from an equilibrium having a biased sex ratio, mutant sex-determining alleles can accumulate only in the case in which in the augmented system all attainable equilibrium states have a sex ratio closer to one to one.
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Lessard S, Karlin S. A criterion for stability--instability at fixation states involving an eigenvalue one with applications in population genetics. Theor Popul Biol 1982; 22:108-26. [PMID: 7147205 DOI: 10.1016/0040-5809(82)90038-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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