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Dambrova M, Makrecka-Kuka M, Kuka J, Vilskersts R, Nordberg D, Attwood MM, Smesny S, Sen ZD, Guo AC, Oler E, Tian S, Zheng J, Wishart DS, Liepinsh E, Schiöth HB. Acylcarnitines: Nomenclature, Biomarkers, Therapeutic Potential, Drug Targets, and Clinical Trials. Pharmacol Rev 2022; 74:506-551. [PMID: 35710135 DOI: 10.1124/pharmrev.121.000408] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acylcarnitines are fatty acid metabolites that play important roles in many cellular energy metabolism pathways. They have historically been used as important diagnostic markers for inborn errors of fatty acid oxidation and are being intensively studied as markers of energy metabolism, deficits in mitochondrial and peroxisomal β -oxidation activity, insulin resistance, and physical activity. Acylcarnitines are increasingly being identified as important indicators in metabolic studies of many diseases, including metabolic disorders, cardiovascular diseases, diabetes, depression, neurologic disorders, and certain cancers. The US Food and Drug Administration-approved drug L-carnitine, along with short-chain acylcarnitines (acetylcarnitine and propionylcarnitine), is now widely used as a dietary supplement. In light of their growing importance, we have undertaken an extensive review of acylcarnitines and provided a detailed description of their identity, nomenclature, classification, biochemistry, pathophysiology, supplementary use, potential drug targets, and clinical trials. We also summarize these updates in the Human Metabolome Database, which now includes information on the structures, chemical formulae, chemical/spectral properties, descriptions, and pathways for 1240 acylcarnitines. This work lays a solid foundation for identifying, characterizing, and understanding acylcarnitines in human biosamples. We also discuss the emerging opportunities for using acylcarnitines as biomarkers and as dietary interventions or supplements for many wide-ranging indications. The opportunity to identify new drug targets involved in controlling acylcarnitine levels is also discussed. SIGNIFICANCE STATEMENT: This review provides a comprehensive overview of acylcarnitines, including their nomenclature, structure and biochemistry, and use as disease biomarkers and pharmaceutical agents. We present updated information contained in the Human Metabolome Database website as well as substantial mapping of the known biochemical pathways associated with acylcarnitines, thereby providing a strong foundation for further clarification of their physiological roles.
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Affiliation(s)
- Maija Dambrova
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Marina Makrecka-Kuka
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Janis Kuka
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Reinis Vilskersts
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Didi Nordberg
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Misty M Attwood
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Stefan Smesny
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Zumrut Duygu Sen
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - An Chi Guo
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Eponine Oler
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Siyang Tian
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Jiamin Zheng
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - David S Wishart
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Edgars Liepinsh
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
| | - Helgi B Schiöth
- Laboratory of Pharmaceutical Pharmacology, Latvian Institute of Organic Synthesis, Riga, Latvia (M.D., M.M.-K., J.K., R.V., E.L.); Section of Functional Pharmacology, Department of Neuroscience, Uppsala University, Uppsala, Sweden, (D.N., M.M.A., H.B.S.); Department of Psychiatry, Jena University Hospital, Jena, Germany (S.S., Z.D.S.); and Department of Biological Sciences, University of Alberta, Edmonton, Canada (A.C.G., E.O., S.T., J.Z., D.S.W.)
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Minigene Splicing Assays Identify 20 Spliceogenic Variants of the Breast/Ovarian Cancer Susceptibility Gene RAD51C. Cancers (Basel) 2022; 14:cancers14122960. [PMID: 35740625 PMCID: PMC9221245 DOI: 10.3390/cancers14122960] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 12/11/2022] Open
Abstract
RAD51C loss-of-function variants are associated with an increased risk of breast and ovarian cancers. Likewise, splicing disruptions are a frequent mechanism of gene inactivation. Taking advantage of a previous splicing-reporter minigene with exons 2-8 (mgR51C_ex2-8), we proceeded to check its impact on the splicing of candidate ClinVar variants. A total of 141 RAD51C variants at the intron/exon boundaries were analyzed with MaxEntScan. Twenty variants were selected and genetically engineered into the wild-type minigene. All the variants disrupted splicing, and 18 induced major splicing anomalies without any trace or minimal amounts (<2.4%) of the minigene full-length (FL) transcript. Twenty-seven transcripts (including the wild-type and r.904A FL transcripts) were identified by fluorescent fragment electrophoresis; of these, 14 were predicted to truncate the RAD51C protein, 3 kept the reading frame, and 8 minor isoforms (1.1−4.7% of the overall expression) could not be characterized. Finally, we performed a tentative interpretation of the variants according to an ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology)-based classification scheme, classifying 16 variants as likely pathogenic. Minigene assays have been proven as valuable tools for the initial characterization of potential spliceogenic variants. Hence, minigene mgR51C_ex2-8 provided useful splicing data for 40 RAD51C variants.
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Dominguez CE, Cunningham D, Venkataramany AS, Chandler DS. Heat increases full-length SMN splicing: promise for splice-augmenting therapies for SMA. Hum Genet 2022; 141:239-256. [PMID: 35088120 DOI: 10.1007/s00439-021-02408-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/30/2021] [Indexed: 11/28/2022]
Abstract
Spinal muscular atrophy (SMA) is a debilitating neurodegenerative pediatric disease characterized by low levels of the survival motor protein (SMN). Humans have two SMN genes that produce identical SMN proteins, but they differ at a key nucleotide in exon 7 that induces differential mRNA splicing. SMN1 primarily produces full-length SMN protein, but due to the spliceosome's inability to efficiently recognize exon 7, SMN2 transcripts are often truncated. SMA occurs primarily through mutations or deletions in the SMN1 gene; therefore, current therapies use antisense oligonucleotides (ASOs) to target exon 7 inclusion in SMN2 mRNA and promote full-length SMN protein production. Here, we explore additional methods that can target SMN splicing and therapeutically increase full-length SMN protein. We demonstrate that in vitro heat treatment of cells increases exon 7 inclusion and relative abundance of full-length SMN2 mRNA and protein, a response that is modulated through the upregulation of the positive splicing factor TRA2 beta. We also observe that HSP90, but not HSP40 or HSP70, in the heat shock response is essential for SMN2 exon 7 splicing under hyperthermic conditions. Finally, we show that pulsatile heat treatments for one hour in vitro and in vivo are effective in increasing full-length SMN2 levels. These findings suggest that timed interval treatments could be a therapeutic alternative for SMA patients who do not respond to current ASO-based therapies or require a unique combination regimen.
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Affiliation(s)
- Catherine E Dominguez
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - David Cunningham
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Akila S Venkataramany
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA.,Medical Scientist Training Program, The Ohio State University, Columbus, OH, USA
| | - Dawn S Chandler
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA. .,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA. .,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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Rossi A, Turturo M, Albano L, Fecarotta S, Barretta F, Crisci D, Gallo G, Perfetto R, Uomo F, Vallone F, Villani G, Strisciuglio P, Parenti G, Frisso G, Ruoppolo M. Long-term monitoring for short/branched-chain acyl-CoA dehydrogenase deficiency: A single-center 4-year experience and open issues. Front Pediatr 2022; 10:895921. [PMID: 36147814 PMCID: PMC9485620 DOI: 10.3389/fped.2022.895921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Short/branched-chain acyl-CoA dehydrogenase deficiency (SBCADD) is an inherited disorder of L-isoleucine metabolism due to mutations in the ACADSB gene. The role of current diagnostic biomarkers [i.e., blood 2-methylbutyrylcarnitine (C5) and urine 2-methylbutyrylglycine (2MBG)] in patient monitoring and the effects of proposed treatments remain uncertain as follow-data are lacking. This study presents first systematic longitudinal biochemical assessment in SBCADD patients. METHODS A retrospective, observational single-center study was conducted on newborns born between 2017 and 2020 and suspected with SBCADD. Biochemical, molecular, clinical and dietary data collected upon NBS recall and during the subsequent follow-up were recorded. RESULTS All enrolled subjects (n = 10) received adequate protein intake and L-carnitine supplementation. Nine subjects were diagnosed with SBCADD. During the follow-up [median: 20.5 (4-40) months] no patient developed symptoms related to SBCADD. No patient normalized serum C5 and urine 2MBG values. In 7/9 SBCADD patients mean serum C5 values decreased or stabilized compared to their first serum C5 value. A major increase in serum C5 values was observed in two patients after L-carnitine discontinuation and during intercurrent illness, respectively. Urine 2MBG values showed moderate intra-patient variability. DISCUSSION The relatively stable serum C5 values observed during L-carnitine supplementation together with C5 increase occurring upon L-carnitine discontinuation/intercurrent illness may support the value of serum C5 as a monitoring biomarker and the benefit of this treatment in SBCADD patients. The role of urine 2MBG in patient monitoring remains uncertain. As all patients were asymptomatic, no association between biochemical parameters and clinical phenotype could be investigated in this study.
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Affiliation(s)
- Alessandro Rossi
- Department of Translational Medicine, Section of Pediatrics, University of Naples "Federico II", Naples, Italy
| | - Mariagrazia Turturo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Lucia Albano
- CEINGE Biotecnologie Avanzate s.c.ar.l, Naples, Italy
| | - Simona Fecarotta
- Department of Translational Medicine, Section of Pediatrics, University of Naples "Federico II", Naples, Italy
| | - Ferdinando Barretta
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.,CEINGE Biotecnologie Avanzate s.c.ar.l, Naples, Italy
| | | | | | - Rosa Perfetto
- CEINGE Biotecnologie Avanzate s.c.ar.l, Naples, Italy
| | - Fabiana Uomo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | | | - Guglielmo Villani
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.,CEINGE Biotecnologie Avanzate s.c.ar.l, Naples, Italy
| | - Pietro Strisciuglio
- Department of Translational Medicine, Section of Pediatrics, University of Naples "Federico II", Naples, Italy
| | - Giancarlo Parenti
- Department of Translational Medicine, Section of Pediatrics, University of Naples "Federico II", Naples, Italy
| | - Giulia Frisso
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.,CEINGE Biotecnologie Avanzate s.c.ar.l, Naples, Italy
| | - Margherita Ruoppolo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.,CEINGE Biotecnologie Avanzate s.c.ar.l, Naples, Italy
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Comprehensive germline-genomic and clinical profiling in 160 unselected children and adolescents with cancer. Eur J Hum Genet 2021; 29:1301-1311. [PMID: 33840814 PMCID: PMC8385053 DOI: 10.1038/s41431-021-00878-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/05/2021] [Accepted: 03/25/2021] [Indexed: 02/02/2023] Open
Abstract
In childhood cancer, the frequency of cancer-associated germline variants and their inheritance patterns are not thoroughly investigated. Moreover, the identification of children carrying a genetic predisposition by clinical means remains challenging. In this single-center study, we performed trio whole-exome sequencing and comprehensive clinical evaluation of a prospectively enrolled cohort of 160 children with cancer and their parents. We identified in 11/160 patients a pathogenic germline variant predisposing to cancer and a further eleven patients carried a prioritized VUS with a strong association to the cancerogenesis of the patient. Through clinical screening, 51 patients (31.3%) were identified as suspicious for an underlying cancer predisposition syndrome (CPS), but only in ten of those patients a pathogenic variant could be identified. In contrast, one patient with a classical CPS and ten patients with prioritized VUS were classified as unremarkable in the clinical work-up. Taken together, a monogenetic causative variant was detected in 13.8% of our patients using WES. Nevertheless, the still unclarified clinical suspicious cases emphasize the need to consider other genetic mechanisms including new target genes, structural variants, or polygenic interactions not previously associated with cancer predisposition.
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Lin Y, Gao H, Lin C, Chen Y, Zhou S, Lin W, Zheng Z, Li X, Li M, Fu Q. Biochemical, Clinical, and Genetic Characteristics of Short/Branched Chain Acyl-CoA Dehydrogenase Deficiency in Chinese Patients by Newborn Screening. Front Genet 2019; 10:802. [PMID: 31555323 PMCID: PMC6727870 DOI: 10.3389/fgene.2019.00802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 07/31/2019] [Indexed: 11/13/2022] Open
Abstract
Short/branched chain acyl-CoA dehydrogenase deficiency (SBCADD) is an autosomal recessive disorder of impaired isoleucine catabolism caused by mutations in the ACADSB gene. There are limited SBCADD cases worldwide and to date no Chinese patients with SBCADD have been reported. The aim of this study was to investigate the biochemical, clinical information, and genotypes of twelve patients with SBCADD in China for the first time. The estimated incidence of SBCADD was 1 in 30,379 in Quanzhou, China. The initial newborn screening (NBS) results revealed that all patients showed slightly or moderately elevated C5 concentrations with C5/C2 and C5/C3 ratios in the reference range, which has the highest risk of being missed. All patients who underwent urinary organic acid analysis showed elevation of 2-methylburtyrylglycine in urine. All patients were asymptomatic at diagnosis, and had normal growth and development during follow-up. Eight different variants in the ACADSB gene, including five previously unreported variants were identified, namely c.596A > G (p.Tyr199Cys), c.653T > C (p.Leu218Pro), c.746del (p.Pro249Leufs*15), c.886G > T (p.Gly296*) and c.923G > A (p.Cys308Tyr). The most common variant was c.1165A > G (33.3%), followed by c.275C > G (20.8%). All previously unreported variants may cause structural damage and dysfunction of SBCAD, as predicted by bioinformatics analysis. Thus, our findings indicate that SBCADD may be more frequent in the Chinese population than previously thought and newborn screening, combined with genetic testing is important for timely diagnosis. Although the clinical course of Chinese patients with SBCADD is likely benign, longitudinal follow-up may be helpful to better understand the natural history of SBCADD.
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Affiliation(s)
- Yiming Lin
- Neonatal Disease Screening Center, Quanzhou Maternal and Children's Hospital, Quanzhou, China
| | - Hongzhi Gao
- Department of Central Laboratory, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Chunmei Lin
- Neonatal Disease Screening Center, Quanzhou Maternal and Children's Hospital, Quanzhou, China
| | - Yanru Chen
- Neonatal Disease Screening Center, Quanzhou Maternal and Children's Hospital, Quanzhou, China
| | - Shuang Zhou
- Department of Central Laboratory, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Weihua Lin
- Neonatal Disease Screening Center, Quanzhou Maternal and Children's Hospital, Quanzhou, China
| | - Zhenzhu Zheng
- Neonatal Disease Screening Center, Quanzhou Maternal and Children's Hospital, Quanzhou, China
| | - Xiaoqing Li
- Department of Neonatal Intensive Care Unit, Quanzhou Maternal and Children's Hospital Quanzhou, China
| | - Min Li
- Zhejiang Biosan Biochemical Technologies Co., Ltd, Hangzhou, China
| | - Qingliu Fu
- Neonatal Disease Screening Center, Quanzhou Maternal and Children's Hospital, Quanzhou, China
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Porta F, Chiesa N, Martinelli D, Spada M. Clinical, biochemical, and molecular spectrum of short/branched-chain acyl-CoA dehydrogenase deficiency: two new cases and review of literature. J Pediatr Endocrinol Metab 2019; 32:101-108. [PMID: 30730842 DOI: 10.1515/jpem-2018-0311] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 12/18/2018] [Indexed: 02/04/2023]
Abstract
Background Short/branched-chain acyl-CoA dehydrogenase (SBCAD) deficiency is a rare inborn error of metabolism with uncertain clinical significance. As it leads to C5-carnitine (i.e. isovalerylcarnitine, 2methylbutyrilcarnitine, or pivaloylcarnitine) elevation, SBCAD deficiency is detectable at newborn screening, requiring differential diagnosis from isovaleric acidemia and pivalic acid administration. Increased urinary excretion of 2-methylbutyrylglycine (2MBG) is the hallmark of SBCAD deficiency. Methods We report two cases of SBCAD deficiency and provide a review of the available literature on this condition. Results Two siblings newly diagnosed with SBCAD deficiency are reported. Newborn screening allowed the early diagnosis in the second-born (C5=0.5 μmol/L, normal 0.05-0.3 μmol/L) and addressed selective screening in the 5-year asymptomatic brother (C5=1.9 μmol/L). Both patients showed increased urinary excretion of 2MBG and two mutations in the ACADSB gene (c.443C>T/c.1145C>T). Currently, both the patients are asymptomatic. Longitudinal biochemical monitoring of the two patients while on treatment with carnitine (100 mg/kg/day) was provided. Based on our experience and the literature review (162 patients), SBCAD deficiency is symptomatic in about 10% of reported patients. Clinical onset occurs in newborns or later in life with seizures, developmental delay, hypotonia, and failure to thrive. On longitudinal follow-up, epilepsy, developmental delay, microcephaly, and autism can develop. Acute metabolic decompensation due to catabolic stressors can occur, as observed in one newly reported patient. Fifteen mutations in the ACADSB gene are known, including the newly identified variant c.1145C>T (p.Thr382Met), variably associated to the phenotype. In the Hmong population, SBCAD deficiency is highly prevalent, mostly due to the founder mutation c.1165A>G, and is largely asymptomatic. Conclusions Although mostly asymptomatic, considering SBCAD deficiency as a non-disease in non-Hmong subjects appears unsafe. Catabolic situations can precipitate acute metabolic decompensation. Carnitine supplementation and valproate avoidance appear to be indicated. Providing an emergency protocol for the management of acute catabolic episodes seems reasonable in asymptomatic patients with SBCAD deficiency. Longitudinal follow-up is recommended.
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Affiliation(s)
- Francesco Porta
- Department of Pediatrics, University of Torino, Torino, Italy
| | | | - Diego Martinelli
- Division of Metabolism, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - Marco Spada
- Department of Pediatrics, University of Torino, Torino, Italy
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Jonsson F, Westin IM, Österman L, Sandgren O, Burstedt M, Holmberg M, Golovleva I. ATP-binding cassette subfamily A, member 4 intronic variants c.4773+3A>G and c.5461-10T>C cause Stargardt disease due to defective splicing. Acta Ophthalmol 2018; 96:737-743. [PMID: 29461686 DOI: 10.1111/aos.13676] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/21/2017] [Indexed: 12/13/2022]
Abstract
PURPOSE Inherited retinal dystrophies (IRDs) represent a group of progressive conditions affecting the retina. There is a great genetic heterogeneity causing IRDs, and to date, more than 260 genes are associated with IRDs. Stargardt disease, type 1 (STGD1) or macular degeneration with flecks, STGD1 represents a disease with early onset, central visual impairment, frequent appearance of yellowish flecks and mutations in the ATP-binding cassette subfamily A, member 4 (ABCA4) gene. A large number of intronic sequence variants in ABCA4 have been considered pathogenic although their functional effect was seldom demonstrated. In this study, we aimed to reveal how intronic variants present in patients with Stargardt from the same Swedish family affect splicing. METHODS The splicing of the ABCA4 gene was studied in human embryonic kidney cells, HEK293T, and in human retinal pigment epithelium cells, ARPE-19, using a minigene system containing variants c.4773+3A>G and c.5461-10T>C. RESULTS We showed that both ABCA4 variants, c.4773+3A>G and c.5461-10T>C, cause aberrant splicing of the ABCA4 minigene resulting in exon skipping. We also demonstrated that splicing of ABCA4 has different outcomes depending on transfected cell type. CONCLUSION Two intronic variants c.4773+3A>G and c.5461-10T>C, both predicted to affect splicing, are indeed disease-causing mutations due to skipping of exons 33, 34, 39 and 40 of ABCA4 gene. The experimental proof that ABCA4 mutations in STGD patients affect protein function is crucial for their inclusion to future clinical trials; therefore, functional testing of all ABCA4 intronic variants associated with Stargardt disease by minigene technology is desirable.
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Affiliation(s)
- Frida Jonsson
- Medical Biosciences/Medical and Clinical Genetics; University of Umeå; Umeå Sweden
| | - Ida Maria Westin
- Medical Biosciences/Medical and Clinical Genetics; University of Umeå; Umeå Sweden
| | - Lennart Österman
- Medical Biosciences/Medical and Clinical Genetics; University of Umeå; Umeå Sweden
| | - Ola Sandgren
- Clinical Sciences/Ophthalmology; University of Umeå; Umeå Sweden
| | - Marie Burstedt
- Clinical Sciences/Ophthalmology; University of Umeå; Umeå Sweden
| | - Monica Holmberg
- Medical Biosciences/Medical and Clinical Genetics; University of Umeå; Umeå Sweden
| | - Irina Golovleva
- Medical Biosciences/Medical and Clinical Genetics; University of Umeå; Umeå Sweden
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9
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Yamazaki N, Kanazawa K, Kimura M, Ike H, Shinomiya M, Tanaka S, Shinohara Y, Minakawa N, Itoh K, Takiguchi Y. Use of modified U1 small nuclear RNA for rescue from exon 7 skipping caused by 5′-splice site mutation of human cathepsin A gene. Gene 2018; 677:41-48. [DOI: 10.1016/j.gene.2018.07.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 06/30/2018] [Accepted: 07/11/2018] [Indexed: 01/04/2023]
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10
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Huerta-Ocampo JA, García-Muñoz MS, Velarde-Salcedo AJ, Hernández-Domínguez EE, González-Escobar JL, Barrera-Pacheco A, Grajales-Lagunes A, Barba de la Rosa AP. The proteome map of the escamolera ant (Liometopum apiculatum Mayr) larvae reveals immunogenic proteins and several hexamerin proteoforms. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2018; 28:107-121. [PMID: 30149319 DOI: 10.1016/j.cbd.2018.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/20/2018] [Accepted: 07/20/2018] [Indexed: 10/28/2022]
Abstract
The larvae of escamolera ant (Liometopum apiculatum Mayr) have been considered a delicacy since Pre-Hispanic times. The increased demand for this stew has led to massive collection of ant nests. Yet biological aspects of L. apiculatum larvae remain unknown, and mapping the proteome of this species is important for understanding its biological characteristics. Two-dimensional gel electrophoresis (2-DE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used to characterize the larvae proteome profile. From 380 protein spots analyzed, 174 were identified by LC-MS/MS and homology search against the Hymenoptera subset of the NCBInr protein database using the Mascot search engine. Peptide de novo sequencing and homology-based alignment allowed the identification of 36 additional protein spots. Identified proteins were classified by cellular location, molecular function, and biological process according to the Gene Ontology annotation. Immunity- and defense-related proteins were identified including PPIases, FK506, PEBP, and chitinases. Several hexamerin proteoforms were identified and the cDNA of the most abundant protein detected in the 2-DE map was isolated and characterized. L. apiculatum hexamerin (LaHEX, GeneBank accession no. MH256667) contains an open reading frame of 2199 bp encoding a polypeptide of 733 amino acid residues with a calculated molecular mass of 82.41 kDa. LaHEX protein is more similar to HEX110 than HEX70 from Apis mellifera. Down-regulation of LaHEX was observed throughout ant development. This work represents the first proteome map as well as the first hexamerin characterized from L. apiculatum larvae.
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Affiliation(s)
- José A Huerta-Ocampo
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José No. 2055, Lomas 4a Sección, 78216 San Luis Potosí, S.L.P, Mexico; CONACYT-Centro de Investigación en Alimentación y Desarrollo A.C., Carretera a La Victoria Km 0.6, Edificio C, C.P 83304 Hermosillo, Sonora, Mexico
| | - María S García-Muñoz
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Nava No.6, Zona Universitaria, C.P. 78200 San Luis Potosí, S.L.P, Mexico
| | - Aída J Velarde-Salcedo
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José No. 2055, Lomas 4a Sección, 78216 San Luis Potosí, S.L.P, Mexico
| | - Eric E Hernández-Domínguez
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José No. 2055, Lomas 4a Sección, 78216 San Luis Potosí, S.L.P, Mexico
| | - Jorge L González-Escobar
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José No. 2055, Lomas 4a Sección, 78216 San Luis Potosí, S.L.P, Mexico
| | - Alberto Barrera-Pacheco
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José No. 2055, Lomas 4a Sección, 78216 San Luis Potosí, S.L.P, Mexico
| | - Alicia Grajales-Lagunes
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Nava No.6, Zona Universitaria, C.P. 78200 San Luis Potosí, S.L.P, Mexico.
| | - Ana P Barba de la Rosa
- IPICyT, Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José No. 2055, Lomas 4a Sección, 78216 San Luis Potosí, S.L.P, Mexico.
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11
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Martínez-Pizarro A, Dembic M, Pérez B, Andresen BS, Desviat LR. Intronic PAH gene mutations cause a splicing defect by a novel mechanism involving U1snRNP binding downstream of the 5' splice site. PLoS Genet 2018; 14:e1007360. [PMID: 29684050 PMCID: PMC5933811 DOI: 10.1371/journal.pgen.1007360] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 05/03/2018] [Accepted: 04/11/2018] [Indexed: 11/18/2022] Open
Abstract
Phenylketonuria (PKU), one of the most common inherited diseases of amino acid metabolism, is caused by mutations in the phenylalanine hydroxylase (PAH) gene. Recently, PAH exon 11 was identified as a vulnerable exon due to a weak 3’ splice site, with different exonic mutations affecting exon 11 splicing through disruption of exonic splicing regulatory elements. In this study, we report a novel intron 11 regulatory element, which is involved in exon 11 splicing, as revealed by the investigated pathogenic effect of variants c.1199+17G>A and c.1199+20G>C, identified in PKU patients. Both mutations cause exon 11 skipping in a minigene system. RNA binding assays indicate that binding of U1snRNP70 to this intronic region is disrupted, concomitant with a slightly increased binding of inhibitors hnRNPA1/2. We have investigated the effect of deletions and point mutations, as well as overexpression of adapted U1snRNA to show that this splicing regulatory motif is important for regulation of correct splicing at the natural 5’ splice site. The results indicate that U1snRNP binding downstream of the natural 5’ splice site determines efficient exon 11 splicing, thus providing a basis for development of therapeutic strategies to correct PAH exon 11 splicing mutations. In this work, we expand the functional effects of non-canonical intronic U1 snRNP binding by showing that it may enhance exon definition and that, consequently, intronic mutations may cause exon skipping by a novel mechanism, where they disrupt stimulatory U1 snRNP binding close to the 5’ splice site. Notably, our results provide further understanding of the reported therapeutic effect of exon specific U1 snRNA for splicing mutations in disease. Splicing defects constitute a major cause of human disease. Mutations affecting conserved splicing sequences at exon-intron junctions are easily recognized as possibly pathogenic, whereas variants in exonic or intronic regions are difficult to classify without functional evidence provided by transcript analysis or in vitro analysis using minigenes. In this work, we sought out to study the pathogenicity of two novel intronic PAH variants identified in phenylketonuria patients. Both mutations resulted in exon skipping in minigenes. We demonstrate that U1snRNP70 binds to the intronic region and that this binding is abolished in the mutant sequences. Correction of the splicing defect was achieved using modified U1 snRNA perfectly complementary to each of the mutant sequences. The results extend the repertoire of natural U1 snRNP cellular functions by including its role as splicing enhancer via binding downstream of the natural 5’ splice site. In addition, our results correlate with the described therapeutic effect of modified U1snRNP for splicing mutations in different genes, thus having a significant impact in the development of specific therapies for splicing defects.
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Affiliation(s)
- Ainhoa Martínez-Pizarro
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Maja Dembic
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Belén Pérez
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
| | - Brage S. Andresen
- Department of Biochemistry and Molecular Biology and the Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
- * E-mail: (BSA); (LRD)
| | - Lourdes R. Desviat
- Centro de Biología Molecular Severo Ochoa UAM-CSIC, CEDEM, CIBERER, IdiPaz, Universidad Autónoma, Madrid, Spain
- * E-mail: (BSA); (LRD)
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12
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Nguyen H, Das U, Wang B, Xie J. The matrices and constraints of GT/AG splice sites of more than 1000 species/lineages. Gene 2018; 660:92-101. [PMID: 29588184 DOI: 10.1016/j.gene.2018.03.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/08/2018] [Accepted: 03/12/2018] [Indexed: 12/11/2022]
Abstract
To provide a resource for the splice sites (SS) of different species, we calculated the matrices of nucleotide compositions of about 38 million splice sites from >1000 species/lineages. The matrices are enriched of aGGTAAGT (5'SS) or (Y)6N(C/t)AG(g/a)t (3'SS) overall; however, they are quite diverse among hundreds of species. The diverse matrices remain prominent even under sequence selection pressures, suggesting the existence of diverse constraints as well as U snRNAs and other spliceosomal factors and/or their interactions with the splice sites. Using an algorithm to measure and compare the splice site constraints across all species, we demonstrate their distinct differences quantitatively. As an example of the resource's application to answering specific questions, we confirm that high constraints of particular positions are significantly associated with transcriptome-wide, increased occurrences of alternative splicing when uncommon nucleotides are present. More interestingly, the abundance of alternative splicing in 16 species correlates with the average constraint index of splice sites in a bell curve. This resource will allow users to assess specific sequences/splice sites against the consensus of every Ensembl-annotated species, and to explore the evolutionary changes or relationship to alternative splicing and transcriptome diversity. Web-search or update features are also included.
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Affiliation(s)
- Hai Nguyen
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - Urmi Das
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Benjamin Wang
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; University of Illinois Urbana-Champaign, IL, USA
| | - Jiuyong Xie
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.
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13
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Schlune A, Riederer A, Mayatepek E, Ensenauer R. Aspects of Newborn Screening in Isovaleric Acidemia. Int J Neonatal Screen 2018; 4:7. [PMID: 33072933 PMCID: PMC7548899 DOI: 10.3390/ijns4010007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 01/22/2018] [Indexed: 12/19/2022] Open
Abstract
Isovaleric acidemia (IVA), an inborn error of leucine catabolism, is caused by mutations in the isovaleryl-CoA dehydrogenase (IVD) gene, resulting in the accumulation of derivatives of isovaleryl-CoA including isovaleryl (C5)-carnitine, the marker metabolite used for newborn screening (NBS). The inclusion of IVA in NBS programs in many countries has broadened knowledge of the variability of the condition, whereas prior to NBS, two distinct clinical phenotypes were known, an "acute neonatal" and a "chronic intermittent" form. An additional biochemically mild and potentially asymptomatic form of IVA and its association with a common missense mutation, c.932C>T (p.A282V), was discovered in subjects identified through NBS. Deficiency of short/branched chain specific acyl-CoA dehydrogenase (2-methylbutyryl-CoA dehydrogenase), a defect of isoleucine degradation whose clinical significance remains unclear, also results in elevated C5-carnitine, and may therefore be detected by NBS for IVA. Treatment strategies for the long-term management of symptomatic IVA comprise the prevention of catabolism, dietary restriction of natural protein or leucine intake, and supplementation with l-carnitine and/or l-glycine. Recommendations on how to counsel and manage individuals with the mild phenotype detected by NBS are required.
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Affiliation(s)
- Andrea Schlune
- Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Anselma Riederer
- Department of Obstetrics and Gynecology, Hospital Altötting-Burghausen, Teaching Hospital of the Ludwig-Maximilians-Universität München, Vinzenz-von-Paul-Strasse 10, 84503 Altötting, Germany
| | - Ertan Mayatepek
- Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Regina Ensenauer
- Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
- Correspondence: ; Tel.: +49-211-81-17687
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14
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Abstract
Apoptosis is an important component of normal tissue physiology, and the prompt removal of apoptotic cells is equally essential to avoid the undesirable consequences of their accumulation and disintegration. Professional phagocytes are highly specialized for engulfing apoptotic cells. The recent ability to track cells that have undergone apoptosis in situ has revealed a division of labor among the tissue resident phagocytes that sample them. Macrophages are uniquely programmed to process internalized apoptotic cell-derived fatty acids, cholesterol and nucleotides, as a reflection of their dominant role in clearing the bulk of apoptotic cells. Dendritic cells carry apoptotic cells to lymph nodes where they signal the emergence and expansion of highly suppressive regulatory CD4 T cells. A broad suppression of inflammation is executed through distinct phagocyte-specific mechanisms. A clever induction of negative regulatory nodes is notable in dendritic cells serving to simultaneously shut down multiple pathways of inflammation. Several of the genes and pathways modulated in phagocytes in response to apoptotic cells have been linked to chronic inflammatory and autoimmune diseases such as atherosclerosis, inflammatory bowel disease and systemic lupus erythematosus. Our collective understanding of old and new phagocyte functions after apoptotic cell phagocytosis demonstrates the enormity of ways to mediate immune suppression and enforce tissue homeostasis.
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Affiliation(s)
- J Magarian Blander
- Jill Roberts Institute for Research in Inflammatory Bowel Disease, Joan and Sanford I. Weill Department of Medicine, Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, New York, NY, USA
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15
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Van Calcar SC, Baker MW, Williams P, Jones SA, Xiong B, Thao MC, Lee S, Yang MK, Rice GM, Rhead W, Vockley J, Hoffman G, Durkin MS. Prevalence and mutation analysis of short/branched chain acyl-CoA dehydrogenase deficiency (SBCADD) detected on newborn screening in Wisconsin. Mol Genet Metab 2013; 110:111-5. [PMID: 23712021 PMCID: PMC5006389 DOI: 10.1016/j.ymgme.2013.03.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 03/29/2013] [Accepted: 03/29/2013] [Indexed: 11/17/2022]
Abstract
Short/branched chain acyl-CoA dehydrogenase deficiency (SBCADD), also called 2-methylbutyryl CoA dehydrogenase deficiency (2-MBCDD), is a disorder of l-isoleucine metabolism of uncertain clinical significance. SBCADD is inadvertently detected on expanded newborn screening by elevated 2-methylbutyrylcarnitine (C5), which has the same mass to charge (m/s) on tandem mass spectrometry (MS/MS) as isovalerylcarnitine (C5), an analyte that is elevated in isovaleric acidemia (IVA), a disorder in leucine metabolism. SBCADD cases identified in the Hmong-American population have been found in association with the c.1165 A>G mutation in the ACADSB gene. The purposes of this study were to: (a) estimate the prevalence of SBCADD and carrier frequency of the c.1165 A>G mutation in the Hmong ethnic group; (b) determine whether the c.1165 A>G mutation is common to all Hmong newborns screening positive for SBCADD; and (c) evaluate C5 acylcarnitine cut-off values to detect and distinguish between SBCADD and IVA diagnoses. During the first 10years of expanded newborn screening using MS/MS in Wisconsin (2001-2011), 97 infants had elevated C5 values (≥0.44μmol/L), of whom five were Caucasian infants confirmed to have IVA. Of the remaining 92 confirmed SBCADD cases, 90 were of Hmong descent. Mutation analysis was completed on an anonymous, random sample of newborn screening cards (n=1139) from Hmong infants. Fifteen infants, including nine who had screened positive for SBCADD based on a C5 acylcarnitine concentration ≥0.44μmol/L, were homozygous for the c.1165 A>G mutation. This corresponds to a prevalence in this ethnic group of being homozygous for the mutation of 1.3% (95% confidence interval 0.8-2.2%) and of being heterozygous for the mutation of 21.8% (95% confidence interval 19.4-24.3%), which is consistent with the Hardy-Weinberg equilibrium. Detection of homozygous individuals who were not identified on newborn screening suggests that the C5 screening cut-off would need to be as low as 0.20μmol/L to detect all infants homozygous for the ACADSB c.1165 A>G mutation. However, lowering the screening cut-off to 0.20 would also result in five "false positive" (non-homozygous) screening results in the Hmong population for every c.1165 A>G homozygote detected. Increasing the cut-off to 0.60μmol/L and requiring elevated C5/C2 (acetylcarnitine) and C5/C3 (propionylcarnitine) ratios to flag a screen as abnormal would reduce the number of infants screening positive, but would still result in an estimated 5 infants with SBCADD per year who would require follow-up and additional biochemical testing to distinguish between SBCADD and IVA diagnoses. Further research is needed to determine the clinical outcomes of SBCADD detected on newborn screening and the c.1165 A>G mutation before knowing whether the optimal screening cut-off would minimize true positives or false negatives for SBCADD associated with this mutation.
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Affiliation(s)
- Sandra C. Van Calcar
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mei W. Baker
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Biochemical Genetics Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin–Madison, Madison, WI, USA
- Newborn Screening Program, Wisconsin State Laboratory of Hygiene, University of Wisconsin–Madison, Madison, WI, USA
| | - Phillip Williams
- Biochemical Genetics Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin–Madison, Madison, WI, USA
| | - Susan A. Jones
- Biochemical Genetics Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin–Madison, Madison, WI, USA
| | - Blia Xiong
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
| | - Mai Choua Thao
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
| | - Sheng Lee
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
| | - Mai Khou Yang
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
| | - Greg M. Rice
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Biochemical Genetics Laboratory, Wisconsin State Laboratory of Hygiene, University of Wisconsin–Madison, Madison, WI, USA
| | - William Rhead
- Genetics Clinic, Children’s Hospital of Wisconsin, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Gary Hoffman
- Newborn Screening Program, Wisconsin State Laboratory of Hygiene, University of Wisconsin–Madison, Madison, WI, USA
| | - Maureen S. Durkin
- Biochemical Genetics Program, Waisman Center, University of Wisconsin–Madison, Madison, WI, USA
- Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Corresponding author at: Population Heath Sciences, University of Wisconsin School of Medicine and Public Health, 1500 Highland Ave., Madison, WI 53705, USA., Fax: +1 608 263 2820., (M.S. Durkin)
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16
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Liu X, Wu L, Deng G, Chen G, Li N, Chu X, Li D. Comparative studies of Acyl-CoA dehydrogenases for monomethyl branched chain substrates in amino acid metabolism. Bioorg Chem 2013; 47:1-8. [PMID: 23474214 DOI: 10.1016/j.bioorg.2012.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 12/05/2012] [Accepted: 12/07/2012] [Indexed: 12/21/2022]
Abstract
Short/branched chain acyl-CoA dehydrogenase (SBCAD), isovaleryl-CoA dehydrogenase (IVD), and isobutyryl-CoA dehydrogenase (IBD) are involved in metabolism of isoleucine, leucine, and valine, respectively. These three enzymes all belong to acyl-CoA dehydrogenase (ACD) family, and catalyze the dehydrogenation of monomethyl branched-chain fatty acid (mmBCFA) thioester derivatives. In the present work, the catalytic properties of rat SBCAD, IVD, and IBD, including their substrate specificity, isomerase activity, and enzyme inhibition, were comparatively studied. Our results indicated that SBCAD has its catalytic properties relatively similar to those of straight-chain acyl-CoA dehydrogenases in terms of their isomerase activity and enzyme inhibition, while IVD and IBD are different. IVD has relatively broader substrate specificity than those of the other two enzymes in accommodating various substrate analogs. The present study increased our understanding for the metabolism of monomethyl branched-chain fatty acids (mmBCFAs) and branched-chain amino acids (BCAAs), which should also be useful for selective control of a particular reaction through the design of specific inhibitors.
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Affiliation(s)
- Xiaojun Liu
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, PR China
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17
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Roca X, Krainer AR, Eperon IC. Pick one, but be quick: 5' splice sites and the problems of too many choices. Genes Dev 2013; 27:129-44. [PMID: 23348838 DOI: 10.1101/gad.209759.112] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Splice site selection is fundamental to pre-mRNA splicing and the expansion of genomic coding potential. 5' Splice sites (5'ss) are the critical elements at the 5' end of introns and are extremely diverse, as thousands of different sequences act as bona fide 5'ss in the human transcriptome. Most 5'ss are recognized by base-pairing with the 5' end of the U1 small nuclear RNA (snRNA). Here we review the history of research on 5'ss selection, highlighting the difficulties of establishing how base-pairing strength determines splicing outcomes. We also discuss recent work demonstrating that U1 snRNA:5'ss helices can accommodate noncanonical registers such as bulged duplexes. In addition, we describe the mechanisms by which other snRNAs, regulatory proteins, splicing enhancers, and the relative positions of alternative 5'ss contribute to selection. Moreover, we discuss mechanisms by which the recognition of numerous candidate 5'ss might lead to selection of a single 5'ss and propose that protein complexes propagate along the exon, thereby changing its physical behavior so as to affect 5'ss selection.
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Affiliation(s)
- Xavier Roca
- School of Biological Sciences, Division of Molecular Genetics and Cell Biology, Nanyang Technological University, Singapore.
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18
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Neurochemical Evidence that the Metabolites Accumulating in 3-Methylcrotonyl-CoA Carboxylase Deficiency Induce Oxidative Damage in Cerebral Cortex of Young Rats. Cell Mol Neurobiol 2012; 33:137-46. [DOI: 10.1007/s10571-012-9879-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/13/2012] [Indexed: 12/13/2022]
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19
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Knebel LA, Zanatta Â, Tonin AM, Grings M, Alvorcem LDM, Wajner M, Leipnitz G. 2-Methylbutyrylglycine induces lipid oxidative damage and decreases the antioxidant defenses in rat brain. Brain Res 2012; 1478:74-82. [PMID: 22967964 DOI: 10.1016/j.brainres.2012.08.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 08/06/2012] [Accepted: 08/22/2012] [Indexed: 11/17/2022]
Abstract
Short/branched chain acyl-CoA dehydrogenase (SBCAD) deficiency is an autosomal recessive disorder of isoleucine metabolism biochemically characterized by accumulation of 2-methylbutyrylglycine (2MBG) and 2-methylbutyric acid (2MB). Affected patients present predominantly neurological symptoms, whose pathophysiology is not yet established. In the present study, we investigated the in vitro effects of 2MBG and 2MB on important parameters of oxidative stress in cerebral cortex of young rats and C6 glioma cells. 2MBG increased thiobarbituric acid-reactive species (TBA-RS), indicating an increase of lipid oxidation. 2MBG induced sulfhydryl oxidation in cortical supernatants and decreased glutathione (GSH) in these brain preparations, as well as in C6 cells, indicating a reduction of nonenzymatic brain antioxidant defenses. In contrast, 2MB did not alter any of these parameters and 2MBG and 2MB did not affect carbonyl formation (protein damage). In addition, 2MBG-induced increase of TBA-RS levels and decrease of GSH were prevented by free radical scavengers, implying that reactive species were involved in these effects. Furthermore, the decrease of GSH levels caused by 2MBG was not due to a direct oxidative action since this metabolite did not alter sulfhydryl content from a commercial solution of GSH. Nitric oxide production was not altered by 2MBG and 2MB, suggesting that reactive oxygen species possibly underlie 2MBG effects. Finally, we verified that 2MBG did not induce cell death in C6 cells. The present data show that 2MBG induces lipid oxidative damage and reduces the antioxidant defenses in rat brain. Therefore, it may be postulated that oxidative stress induced by 2MBG is involved, at least in part, in the pathophysiology of the brain damage found in SBCAD deficiency.
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Affiliation(s)
- Lisiane Aurélio Knebel
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90035003, Brazil
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20
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21
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Betz B, Theiss S, Aktas M, Konermann C, Goecke TO, Möslein G, Schaal H, Royer-Pokora B. Comparative in silico analyses and experimental validation of novel splice site and missense mutations in the genes MLH1 and MSH2. J Cancer Res Clin Oncol 2011; 136:123-34. [PMID: 19669161 DOI: 10.1007/s00432-009-0643-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 07/17/2009] [Indexed: 12/24/2022]
Abstract
Hereditary non-polyposis colorectal cancer, an autosomal dominant predisposition to colorectal cancer and other malignancies, is caused by inactivating mutations of DNA mismatch repair genes, mainly MLH1 and MSH2. Missense mutations affect protein structure or function, but may also cause aberrant splicing, if located within splice sites (ss) or cis-acting sequences of splicing regulatory proteins, i.e., exonic splicing enhancers or exonic splicing silencers. Despite significant progress of ss scoring algorithms, the prediction for the impact of mutations on splicing is still unsatisfactory. For this study, we assessed ten ss and nine missense mutations outside ss in MLH1 and MSH2, including eleven newly identified mutations, and experimentally analyzed their effect at the RNA level. We additionally tested and compared the reliability of several web-based programs for the prediction of splicing outcome for these mutations.
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Affiliation(s)
- Beate Betz
- Institut fuer Humangenetik, Universitaetsklinikum Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany
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22
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Dobrowolski SF, Andersen HS, Doktor TK, Andresen BS. The phenylalanine hydroxylase c.30C>G synonymous variation (p.G10G) creates a common exonic splicing silencer. Mol Genet Metab 2010; 100:316-23. [PMID: 20457534 DOI: 10.1016/j.ymgme.2010.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 04/07/2010] [Indexed: 11/30/2022]
Abstract
PKU is caused by mutations in PAH. A c.30C>G synonymous variation in exon 1, previously reported as neutral, was observed in two patients. The variation creates a GGG triplet, which is part of several exonic splicing silencer (ESS) motifs. Because the 5'-splice site of PAH exon 1 is intrinsically weak and therefore could be responsive to a new flanking ESS, we hypothesized that c.30C>G could cause aberrant mRNA splicing. We demonstrate that c.30C>G causes aberrant mRNA splicing in two different reporter minigenes, and that this is abolished if a preexisting flanking GGG triplet is disrupted. GGG triplets are part of the consensus motif bound by splicing-inhibitory hnRNPH proteins and we observed a dramatic increase in hnRNPH binding to c.30C>G PAH RNA. We conclude that c.30C>G creates a hnRNPH-binding ESS, which can disrupt mRNA splicing. A disease-causing mutation in HEXB, which has previously been associated with exon skipping in patients also creates a GGG triplet. We show that the mutant HEXB motif causes exon skipping of a reporter minigene and that this is also influenced by a flanking GGG triplet. We suggest that aberrant splicing caused by creation/abolishment of GGG triplets located together with a preexisting flanking GGG triplet, may be an underreported cause of human disease. It is important to recognize that exonic sequence changes may disrupt mRNA splicing. This is particularly important in PAH, since PKU patients harboring such mutations are unlikely to respond to therapy with 6R-tetrahydrobiopterin (BH(4)), despite the fact that the genetic code indicates otherwise.
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Affiliation(s)
- Steven F Dobrowolski
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, UT, USA
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23
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Alfardan J, Mohsen AW, Copeland S, Ellison J, Keppen-Davis L, Rohrbach M, Powell BR, Gillis J, Matern D, Kant J, Vockley J. Characterization of new ACADSB gene sequence mutations and clinical implications in patients with 2-methylbutyrylglycinuria identified by newborn screening. Mol Genet Metab 2010; 100:333-8. [PMID: 20547083 PMCID: PMC2906669 DOI: 10.1016/j.ymgme.2010.04.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 04/23/2010] [Indexed: 12/19/2022]
Abstract
Short/branched chain acyl-CoA dehydrogenase (SBCAD) deficiency, also known as 2-methylbutyryl-CoA dehydrogenase deficiency, is a recently described autosomal recessive disorder of isoleucine metabolism. Most patients reported thus far have originated from a founder mutation in the Hmong Chinese population. While the first reported patients had severe disease, most of the affected Hmong have remained asymptomatic. In this study, we describe 11 asymptomatic non-Hmong patients brought to medical attention by elevated C5-carnitine found by newborn screening and one discovered because of clinical symptoms. The diagnosis of SBCAD deficiency was determined by metabolite analysis of blood, urine, and fibroblast samples. PCR and bidirectional sequencing were performed on genomic DNA from five of the patients covering the entire SBCAD (ACADSB) gene sequence of 11 exons. Sequence analysis of genomic DNA from each patient identified variations in the SBCAD gene not previously reported. Escherichia coli expression studies revealed that the missense mutations identified lead to inactivation or instability of the mutant SBCAD enzymes. These findings confirm that SBCAD deficiency can be identified through newborn screening by acylcarnitine analysis. Our patients have been well without treatment and call for careful follow-up studies to learn the true clinical impact of this disorder.
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Affiliation(s)
| | | | | | | | | | - Marianne Rohrbach
- Hospital for Sick Children and University of Toronto, Ontario, Canada
- University Children‘s Hospital Zürich, Switzerland
| | | | - Jane Gillis
- IWK Health Centre and Dalhousie University, Halifax, Canada
| | | | - Jeffrey Kant
- University of Pittsburgh School of Medicine, USA
| | - Jerry Vockley
- University of Pittsburgh School of Medicine, USA
- University of Pittsburgh Graduate School of Public Health, USA
- Correspondence to: Jerry Vockley, University of Pittsburgh School of Medicine, The Children’s Hospital of Pittsburgh, Department of Pediatrics, 4401 Penn Avenue, Pittsburgh, PA 15224.
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Homolova K, Zavadakova P, Doktor TK, Schroeder LD, Kozich V, Andresen BS. The deep intronic c.903+469T>C mutation in the MTRR gene creates an SF2/ASF binding exonic splicing enhancer, which leads to pseudoexon activation and causes the cblE type of homocystinuria. Hum Mutat 2010; 31:437-44. [PMID: 20120036 PMCID: PMC3429857 DOI: 10.1002/humu.21206] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Deep intronic mutations are often ignored as possible causes of human diseases. A deep intronic mutation in the MTRR gene, c.903+469T>C, is the most frequent mutation causing the cblE type of homocystinuria. It is well known to be associated with pre-mRNA mis-splicing, resulting in pseudoexon inclusion; however, the pathological mechanism remains unknown. We used minigenes to demonstrate that this mutation is the direct cause of MTRR pseudoexon inclusion, and that the pseudoexon is normally not recognized due to a suboptimal 5' splice site. Within the pseudoexon we identified an exonic splicing enhancer (ESE), which is activated by the mutation. Cotransfection and siRNA experiments showed that pseudoexon inclusion depends on the cellular amounts of SF2/ASF and in vitro RNA-binding assays showed dramatically increased SF2/ASF binding to the mutant MTRR ESE. The mutant MTRR ESE sequence is identical to an ESE of the alternatively spliced MST1R proto-oncogene, which suggests that this ESE could be frequently involved in splicing regulation. Our study conclusively demonstrates that an intronic single nucleotide change is sufficient to cause pseudoexon activation via creation of a functional ESE, which binds a specific splicing factor. We suggest that this mechanism may cause genetic disease much more frequently than previously reported.
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Affiliation(s)
- Katerina Homolova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague 2, Czech Republic
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25
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Guédard-Méreuze SL, Vaché C, Molinari N, Vaudaine J, Claustres M, Roux AF, Tuffery-Giraud S. Sequence contexts that determine the pathogenicity of base substitutions at position +3 of donor splice-sites. Hum Mutat 2009; 30:1329-39. [DOI: 10.1002/humu.21070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Sass JO, Ensenauer R, Röschinger W, Reich H, Steuerwald U, Schirrmacher O, Engel K, Häberle J, Andresen BS, Mégarbané A, Lehnert W, Zschocke J. 2-Methylbutyryl-coenzyme A dehydrogenase deficiency: functional and molecular studies on a defect in isoleucine catabolism. Mol Genet Metab 2008; 93:30-5. [PMID: 17945527 DOI: 10.1016/j.ymgme.2007.09.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 09/01/2007] [Indexed: 11/25/2022]
Abstract
2-Methylbutyryl-CoA dehydrogenase (MBD; coded by the ACADSB gene) catalyzes the step in isoleucine metabolism that corresponds to the isovaleryl-CoA dehydrogenase reaction in the degradation of leucine. Deficiencies of both enzymes may be detected by expanded neonatal screening with tandem-mass spectrometry due to elevated pentanoylcarnitine (C5 acylcarnitine) in blood, but little information is available on the clinical relevance of MBD deficiency. We biochemically and genetically characterize six individuals with MBD deficiency from four families of different ethnic backgrounds. None of the six individuals showed clinical symptoms attributable to MBD deficiency although the defect in isoleucine catabolism was demonstrated both in vivo and in vitro. Several mutations in the ACADSB gene were identified, including a novel one. MBD deficiency may be a harmless metabolic variant although significant impairment of valproic acid metabolism cannot be excluded and further study is required to assess the long-term outcome of individuals with this condition. The relatively high prevalence of ACADSB gene mutations in control subjects suggests that MBD deficiency may be more common than previously thought but is not detected because of its usually benign nature.
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Affiliation(s)
- Jörn Oliver Sass
- Zentrum für Kinder-und Jugendmedizin, Universitätsklinikum Freiburg, Mathildenstrasse 1, Freiburg, Germany.
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27
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Roca X, Olson AJ, Rao AR, Enerly E, Kristensen VN, Børresen-Dale AL, Andresen BS, Krainer AR, Sachidanandam R. Features of 5'-splice-site efficiency derived from disease-causing mutations and comparative genomics. Genome Res 2007; 18:77-87. [PMID: 18032726 DOI: 10.1101/gr.6859308] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Many human diseases, including Fanconi anemia, hemophilia B, neurofibromatosis, and phenylketonuria, can be caused by 5'-splice-site (5'ss) mutations that are not predicted to disrupt splicing, according to position weight matrices. By using comparative genomics, we identify pairwise dependencies between 5'ss nucleotides as a conserved feature of the entire set of 5'ss. These dependencies are also conserved in human-mouse pairs of orthologous 5'ss. Many disease-associated 5'ss mutations disrupt these dependencies, as can some human SNPs that appear to alter splicing. The consistency of the evidence signifies the relevance of this approach and suggests that 5'ss SNPs play a role in complex diseases.
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Affiliation(s)
- Xavier Roca
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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28
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Kanavin OJ, Woldseth B, Jellum E, Tvedt B, Andresen BS, Stromme P. 2-methylbutyryl-CoA dehydrogenase deficiency associated with autism and mental retardation: a case report. J Med Case Rep 2007; 1:98. [PMID: 17883863 PMCID: PMC2045671 DOI: 10.1186/1752-1947-1-98] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 09/20/2007] [Indexed: 11/18/2022] Open
Abstract
Background 2-methylbutyryl-CoA dehydrogenase deficiency or short/branched chain acyl-CoA dehydrogenase deficiency (SBCADD) is caused by a defect in the degradation pathway of the amino acid L-isoleucine. Methods We report a four-year-old mentally retarded Somali boy with autism and a history of seizures, who was found to excrete increased amounts of 2-methylbutyryl glycine in the urine. The SBCAD gene was examined with sequence analysis. His development was assessed with psychometric testing before and after a trial with low protein diet. Results We found homozygosity for A > G changing the +3 position of intron 3 (c.303+3A > G) in the SBCAD gene. Psychometric testing showed moderate mental retardation and behavioral scores within the autistic spectrum. No beneficial effect was detected after 5 months with a low protein diet. Conclusion This mutation was also found in two previously reported cases with SBCADD, both originating from Somalia and Eritrea, indicating that it is relatively prevalent in this population. Autism has not previously been described with mutations in this gene, thus expanding the clinical spectrum of SBCADD.
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Affiliation(s)
- Oivind J Kanavin
- Department of Pediatrics, Ullevål University Hospital, Oslo, Norway
| | - Berit Woldseth
- Department of Clinical Chemistry, Rikshospitalet-Radiumhospitalet Medical Center, Oslo, Norway
| | - Egil Jellum
- Department of Clinical Chemistry, Rikshospitalet-Radiumhospitalet Medical Center, Oslo, Norway
| | - Bjorn Tvedt
- Department of Pediatrics, Ullevål University Hospital, Oslo, Norway
| | - Brage S Andresen
- Research Unit for Molecular Medicine, Skejby Sygehus, DK 8200, Århus N, Denmark
- Institute of Human Genetics, Aarhus University, Aarhus, Denmark
| | - Petter Stromme
- Department of Pediatrics, Ullevål University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Norway
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Korman SH. Inborn errors of isoleucine degradation: a review. Mol Genet Metab 2006; 89:289-99. [PMID: 16950638 DOI: 10.1016/j.ymgme.2006.07.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 07/27/2006] [Accepted: 07/27/2006] [Indexed: 11/28/2022]
Abstract
Three inborn errors have been identified in the pathway of isoleucine degradation. Deficiency of beta-ketothiolase (beta-KT, also known as T2, mitochondrial acetoacetyl-CoA thiolase and acetyl-CoA acetyltransferase 1) is a well-described disorder which presents with acute episodic ketoacidosis. In contrast, short/branched-chain acyl-CoA dehydrogenase (SBCAD) and 2-methyl-3-hydroxybutyryl-CoA dehydrogenase (MHBD) deficiencies are recently described and relatively rare defects which present with predominantly neurological manifestations, although acute metabolic decompensation may occur in the early newborn period. Careful examination of urine organic acids is required for identification and differential diagnosis of these disorders, with awareness that the abnormalities may be subtle and variable. Tandem MS analysis of acylcarnitines may reveal elevated C5 (SBCAD) or C5:1 and/or OH-C5 species (MHBD and beta-KT deficiencies) but the abnormalities are non-diagnostic and may be intermittent or absent. Confirmation of diagnosis is therefore advisable by specific enzyme assay and/or mutation analysis of the ACAT1 (beta-KT), ACADSB (SBCAD) or HADH2 (MHBD) genes. The latter is located on the X chromosome, accounting for the milder clinical phenotype in females. If beta-KT deficiency is diagnosed early and treated by fasting avoidance and modest protein restriction, ketoacidosis episodes can be prevented and the prognosis is excellent. The role of treatment in SBCAD deficiency remains unclear pending further delineation of its clinical phenotype and pathogenicity, particularly regarding asymptomatic individuals detected by expanded newborn screening. The ineffectiveness of isoleucine restriction in MHBD deficiency is consistent with the additional roles of this multifunctional enzyme in sex steroid and neurosteroid metabolism and its interaction with amyloid-beta peptide.
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Affiliation(s)
- Stanley H Korman
- Metabolic Diseases Unit, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel.
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30
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Desviat LR, Clavero S, Perez-Cerdá C, Navarrete R, Ugarte M, Perez B. New splicing mutations in propionic acidemia. J Hum Genet 2006; 51:992-997. [PMID: 17051315 DOI: 10.1007/s10038-006-0068-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 08/05/2006] [Indexed: 12/12/2022]
Abstract
Propionic acidemia results from mutations in either of the two genes, PCCA or PCCB, that encode the two subunits of the propionyl-CoA carboxylase (PCC) enzyme. In this study, we report the identification and analysis of seven novel splicing mutations involving consensus donor and acceptor splice sites. Most of them were identified in patients with a Central Asian origin, and some present in several alleles, probably reflecting founder effects. The functional consequences of the splicing mutations were analyzed in patients' fibroblasts, as well as transcript quantification using real-time PCR methods. In the PCCA gene, two mutations were demonstrated to affect 5' splice sites (c.231+1G>C and c.1209+3A>G) and two 3' acceptor splice sites (c.1210delG and c.1430G>T), all causing skipping of the exons involved, with no detectable levels of normally spliced transcript. In the PCCB gene, all three mutations involved 5' donor splice sites-two affected exon 1 splicing (c.154_183+17del46 and c.183+2T>C), the latter activating a cryptic splice site in intron 1, and the remaining mutation (c.1498+2T>C) resulted in exon 14 skipping. The results highlight the necessity to perform transcript analysis in addition to genomic DNA sequencing to characterize the effect of splicing mutations and add relevant information on the genetic epidemiology of the disease.
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Affiliation(s)
- Lourdes R Desviat
- Centro de Biología Molecular "Severo Ochoa" CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Sonia Clavero
- Centro de Biología Molecular "Severo Ochoa" CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Celia Perez-Cerdá
- Centro de Biología Molecular "Severo Ochoa" CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Rosa Navarrete
- Centro de Biología Molecular "Severo Ochoa" CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | - Magdalena Ugarte
- Centro de Biología Molecular "Severo Ochoa" CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain.
| | - Belen Perez
- Centro de Biología Molecular "Severo Ochoa" CSIC-UAM, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
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31
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Maydan G, Andresen BS, Madsen PP, Zeigler M, Raas-Rothschild A, Zlotogorski A, Gutman A, Korman SH. TAT gene mutation analysis in three Palestinian kindreds with oculocutaneous tyrosinaemia type II; characterization of a silent exonic transversion that causes complete missplicing by exon 11 skipping. J Inherit Metab Dis 2006; 29:620-6. [PMID: 16917729 DOI: 10.1007/s10545-006-0407-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2006] [Revised: 07/21/2006] [Accepted: 08/01/2006] [Indexed: 10/24/2022]
Abstract
Deficiency of the hepatic cytosolic enzyme tyrosine aminotransferase (TAT) causes marked hypertyrosinaemia leading to painful palmoplantar hyperkeratoses, pseudodendritic keratitis and variable mental retardation (oculocutaneous tyrosinaemia type II or Richner-Hanhart syndrome). Parents may therefore seek prenatal diagnosis, but this is not possible by biochemical assays as tyrosine does not accumulate in amniotic fluid and TAT is not expressed in chorionic villi or amniocytes. Molecular analysis is therefore the only possible approach for prenatal diagnosis and carrier detection. To this end, we sought TAT gene mutations in 9 tyrosinaemia II patients from three consanguineous Palestinian kindreds. In two kindreds (7 patients), the only potential abnormality identified after sequencing all 12 exons and exon-intron boundaries was homozygosity for a silent, single-nucleotide transversion c.1224G > T (p.T408T) at the last base of exon 11. This was predicted to disrupt the 5' donor splice site of exon 11 and result in missplicing. However, as TAT is expressed exclusively in liver, patient mRNA could not be obtained for splicing analysis. A minigene approach was therefore used to assess the effect of c.1224G > T on exon 11 splicing. Transfection experiments with wild-type and c.1224G > T mutant minigene constructs demonstrated that c.1224G > T results in complete exon 11 skipping, illustrating the utility of this approach for confirming a putative splicing defect when cDNA is unavailable. Homozygosity for a c.1249C > T (R417X) exon 12 nonsense mutation (previously reported in a French patient) was identified in both patients from the third kindred, enabling successful prenatal diagnosis of an unaffected fetus using chorionic villous tissue.
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Affiliation(s)
- G Maydan
- Department of Clinical Biochemistry, Hadassah--Hebrew University Medical Center, Jerusalem, Israel
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