1
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Matsell E, Andersen JP, Molday RS. Functional and in silico analysis of ATP8A2 and other P4-ATPase variants associated with human genetic diseases. Dis Model Mech 2024; 17:dmm050546. [PMID: 38436085 PMCID: PMC11073571 DOI: 10.1242/dmm.050546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 02/21/2024] [Indexed: 03/05/2024] Open
Abstract
P4-ATPases flip lipids from the exoplasmic to cytoplasmic leaflet of cell membranes, a property crucial for many biological processes. Mutations in P4-ATPases are associated with severe inherited and complex human disorders. We determined the expression, localization and ATPase activity of four variants of ATP8A2, the P4-ATPase associated with the neurodevelopmental disorder known as cerebellar ataxia, impaired intellectual development and disequilibrium syndrome 4 (CAMRQ4). Two variants, G447R and A772P, harboring mutations in catalytic domains, expressed at low levels and mislocalized in cells. In contrast, the E459Q variant in a flexible loop displayed wild-type expression levels, Golgi-endosome localization and ATPase activity. The R1147W variant expressed at 50% of wild-type levels but showed normal localization and activity. These results indicate that the G447R and A772P mutations cause CAMRQ4 through protein misfolding. The E459Q mutation is unlikely to be causative, whereas the R1147W may display a milder disease phenotype. Using various programs that predict protein stability, we show that there is a good correlation between the experimental expression of the variants and in silico stability assessments, suggesting that such analysis is useful in identifying protein misfolding disease-associated variants.
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Affiliation(s)
- Eli Matsell
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | - Robert S. Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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2
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Flannery KP, Safwat S, Matsell E, Battula N, Hamed AAA, Mohamed IN, Elseed MA, Koko M, Abubaker R, Abozar F, Elsayed LEO, Bhise V, Molday RS, Salih MA, Yahia A, Manzini MC. A novel missense variant in the ATPase domain of ATP8A2 and review of phenotypic variability of ATP8A2-related disorders caused by missense changes. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.15.24306843. [PMID: 38798571 PMCID: PMC11118633 DOI: 10.1101/2024.05.15.24306843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
ATPase, class 1, type 8A, member 2 (ATP8A2) is a P4-ATPase with a critical role in phospholipid translocation across the plasma membrane. Pathogenic variants in ATP8A2 are known to cause cerebellar ataxia, mental retardation, and disequilibrium syndrome 4 (CAMRQ4) which is often associated with encephalopathy, global developmental delay, and severe motor deficits. Here, we present a family with two siblings presenting with global developmental delay, intellectual disability, spasticity, ataxia, nystagmus, and thin corpus callosum. Whole exome sequencing revealed a homozygous missense variant in the nucleotide binding domain of ATP8A2 (p.Leu538Pro) that results in near complete loss of protein expression. This is in line with other missense variants in the same domain leading to protein misfolding and loss of ATPase function. In addition, by performing diffusion-weighted imaging, we identified bilateral hyperintensities in the posterior limbs of the internal capsule suggesting possible microstructural changes in axon tracts that had not been appreciated before and could contribute to the sensorimotor deficits in these individuals.
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Affiliation(s)
- Kyle P. Flannery
- Department of Neuroscience & Cell Biology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901
| | - Sylvia Safwat
- Department of Neuroscience & Cell Biology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Eli Matsell
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| | - Namarata Battula
- Department of Neuroscience & Cell Biology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901
| | | | | | - Maha A. Elseed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Mahmoud Koko
- Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Rayan Abubaker
- Sudanese Neurogenetics Research group, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Fatima Abozar
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Liena E. O. Elsayed
- Department of Basic Sciences, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, P.O.Box 84428, Riyadh 11671, Saudi Arabia
| | - Vikram Bhise
- Department of Pediatrics and Neurology, Rutgers – Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Robert S. Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| | - Mustafa A. Salih
- Consultant Pediatric Neurologist, Health Sector, King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia
| | - Ashraf Yahia
- Department of Biochemistry, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research, Department of Women’s and Children’s Health, Karolinska Institutet and Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
- Astrid Lindgren Children’s Hospital, Karolinska University Hospital, Solna, Sweden
| | - M. Chiara Manzini
- Department of Neuroscience & Cell Biology, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901
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3
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Teov B, Janchevska A, Beqiri-Jasari A, Tasic V, Kungulovski G, Gucev Z. Compound Heterozygosity in Cerebellar Ataxia, Mental Retardation, and Disequilibrium Syndrome Type 4. Pril (Makedon Akad Nauk Umet Odd Med Nauki) 2023; 44:85-90. [PMID: 38109455 DOI: 10.2478/prilozi-2023-0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Cerebellar ataxia, mental retardation, and disequilibrium syndrome (CAMRQ) is a genetically and clinically heterogeneous disorder with four described subtypes. Autosomal recessive syndrome of cerebellar ataxia, mental retardation, and disequilibrium type 4 (CAMRQ4) is caused by mutations in the ATP8A2 gene. We report an 8-year-old boy with choreoathetosis, hypotonia, without the ability to keep his head up and profound mental retardation. There was quadrupedal locomotion, as well. MRI of the brain revealed a hypotrophy of the corpus callosum, diffuse white matter reduction, widespread delayed myelination and ventriculomegaly. Trio whole-exome sequencing revealed compound heterozygosity in the ATP8A2 gene consisting of a known variant c.1756C>T (p.Arg586*) inherited from the mother and a novel variant c.691_701delCTGATGAAGTT (p.Leu231fs) inherited from the father. CAMRQ type 4 has been found in about 50 patients. To the best of our knowledge, this is the first reported patient with CAMRQ4 with these gene variants. The clinical presentation is severe.
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Affiliation(s)
- Bojan Teov
- 1University Children's Hospital, Medical Faculty Skopje, North Macedonia
| | | | | | - Velibor Tasic
- 1University Children's Hospital, Medical Faculty Skopje, North Macedonia
| | | | - Zoran Gucev
- 1University Children's Hospital, Medical Faculty Skopje, North Macedonia
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4
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Tamura R, Sabu Y, Mizuno T, Mizuno S, Nakano S, Suzuki M, Abukawa D, Kaji S, Azuma Y, Inui A, Okamoto T, Shimizu S, Fukuda A, Sakamoto S, Kasahara M, Takahashi S, Kusuhara H, Zen Y, Ando T, Hayashi H. Intestinal Atp8b1 dysfunction causes hepatic choline deficiency and steatohepatitis. Nat Commun 2023; 14:6763. [PMID: 37990006 PMCID: PMC10663612 DOI: 10.1038/s41467-023-42424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 10/11/2023] [Indexed: 11/23/2023] Open
Abstract
Choline is an essential nutrient, and its deficiency causes steatohepatitis. Dietary phosphatidylcholine (PC) is digested into lysoPC (LPC), glycerophosphocholine, and choline in the intestinal lumen and is the primary source of systemic choline. However, the major PC metabolites absorbed in the intestinal tract remain unidentified. ATP8B1 is a P4-ATPase phospholipid flippase expressed in the apical membrane of the epithelium. Here, we use intestinal epithelial cell (IEC)-specific Atp8b1-knockout (Atp8b1IEC-KO) mice. These mice progress to steatohepatitis by 4 weeks. Metabolomic analysis and cell-based assays show that loss of Atp8b1 in IEC causes LPC malabsorption and thereby hepatic choline deficiency. Feeding choline-supplemented diets to lactating mice achieves complete recovery from steatohepatitis in Atp8b1IEC-KO mice. Analysis of samples from pediatric patients with ATP8B1 deficiency suggests its translational potential. This study indicates that Atp8b1 regulates hepatic choline levels through intestinal LPC absorption, encouraging the evaluation of choline supplementation therapy for steatohepatitis caused by ATP8B1 dysfunction.
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Affiliation(s)
- Ryutaro Tamura
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Science, The University of Tokyo, Tokyo, Japan
| | - Yusuke Sabu
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Science, The University of Tokyo, Tokyo, Japan
| | - Tadahaya Mizuno
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Science, The University of Tokyo, Tokyo, Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center and Trans-Border Medical Research Center, University of Tsukuba, Ibaraki, Japan
| | - Satoshi Nakano
- Department of Pediatrics, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Mitsuyoshi Suzuki
- Department of Pediatrics, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Daiki Abukawa
- Department of Gastroenterology and Hepatology, Miyagi Children's Hospital, Miyagi, Japan
| | - Shunsaku Kaji
- Department of Pediatrics, Tsuyama-Chuo Hospital, Okayama, Japan
| | - Yoshihiro Azuma
- Department of Pediatrics, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Ayano Inui
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama City Eastern Hospital, Kanagawa, Japan
| | - Tatsuya Okamoto
- Department of Pediatric Surgery, Kyoto University Hospital, Kyoto, Japan
| | - Seiichi Shimizu
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Akinari Fukuda
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Seisuke Sakamoto
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Mureo Kasahara
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Satoru Takahashi
- Laboratory Animal Resource Center and Trans-Border Medical Research Center, University of Tsukuba, Ibaraki, Japan
| | - Hiroyuki Kusuhara
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Science, The University of Tokyo, Tokyo, Japan
| | - Yoh Zen
- Institute of Liver Studies, King's College Hospital & King's College London, London, UK
| | - Tomohiro Ando
- Axcelead Drug Discovery Partners, Inc., Fujisawa, Kanagawa, Japan
| | - Hisamitsu Hayashi
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Science, The University of Tokyo, Tokyo, Japan.
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5
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Meng T, Chen X, He Z, Huang H, Lin S, Liu K, Bai G, Liu H, Xu M, Zhuang H, Zhang Y, Waqas A, Liu Q, Zhang C, Sun XD, Huang H, Umair M, Yan Y, Feng D. ATP9A deficiency causes ADHD and aberrant endosomal recycling via modulating RAB5 and RAB11 activity. Mol Psychiatry 2023; 28:1219-1231. [PMID: 36604604 PMCID: PMC9816018 DOI: 10.1038/s41380-022-01940-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 12/10/2022] [Accepted: 12/22/2022] [Indexed: 01/07/2023]
Abstract
ATP9A, a lipid flippase of the class II P4-ATPases, is involved in cellular vesicle trafficking. Its homozygous variants are linked to neurodevelopmental disorders in humans. However, its physiological function, the underlying mechanism as well as its pathophysiological relevance in humans and animals are still largely unknown. Here, we report two independent families in which the nonsense mutations c.433C>T/c.658C>T/c.983G>A (p. Arg145*/p. Arg220*/p. Trp328*) in ATP9A (NM_006045.3) cause autosomal recessive hypotonia, intellectual disability (ID) and attention deficit hyperactivity disorder (ADHD). Atp9a null mice show decreased muscle strength, memory deficits and hyperkinetic movement disorder, recapitulating the symptoms observed in patients. Abnormal neurite morphology and impaired synaptic transmission are found in the primary motor cortex and hippocampus of the Atp9a null mice. ATP9A is also required for maintaining neuronal neurite morphology and the viability of neural cells in vitro. It mainly localizes to endosomes and plays a pivotal role in endosomal recycling pathway by modulating small GTPase RAB5 and RAB11 activation. However, ATP9A pathogenic mutants have aberrant subcellular localization and cause abnormal endosomal recycling. These findings provide strong evidence that ATP9A deficiency leads to neurodevelopmental disorders and synaptic dysfunctions in both humans and mice, and establishes novel regulatory roles for ATP9A in RAB5 and RAB11 activity-dependent endosomal recycling pathway and neurological diseases.
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Affiliation(s)
- Tian Meng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China.,Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China.,State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Xiaoting Chen
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China
| | - Zhengjie He
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China.,Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
| | - Haofeng Huang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China
| | - Shiyin Lin
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China
| | - Kunru Liu
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China
| | - Guo Bai
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China
| | - Hao Liu
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China.,State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China.,Qingyuan People's Hospital, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, 511500, China
| | - Mindong Xu
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Haixia Zhuang
- Department of Anesthesiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, China
| | - Yunlong Zhang
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Ahmed Waqas
- Department of Zoology, Division of Science and Technology, University of Education, Lahore, 54000, Pakistan
| | - Qian Liu
- Department of Cerebrovascular Disease Center, Gansu Provincial Hospital, Lanzhou, 730000, China
| | - Chuan Zhang
- Medical Genetics Center, Gansu Provincial Maternity and Child-care Hospital; Gansu Provincial Clinical Research Center for Birth Defects and Rare Diseases, Lanzhou, 730050, China
| | - Xiang-Dong Sun
- Key Laboratory of Neuroscience, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Huansen Huang
- Department of Anesthesiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510260, China
| | - Muhammad Umair
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, 11481, Saudi Arabia. .,Department of Life Sciences, School of Science, University of Management and Technology (UMT), Lahore, 22209, Pakistan.
| | - Yousheng Yan
- Prenatal Diagnostic Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, 100026, China.
| | - Du Feng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 510095, China. .,Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China. .,State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China.
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6
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Liu C, Zhang S, Shi H, Zhou H, Zhuang J, Cao Y, Ward N, Wang J. Atp11b Deletion Affects the Gut Microbiota and Accelerates Brain Aging in Mice. Brain Sci 2022; 12:brainsci12060709. [PMID: 35741595 PMCID: PMC9221138 DOI: 10.3390/brainsci12060709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 11/25/2022] Open
Abstract
The microbiota-gut-brain axis has attracted significant attention with respect to studying the mechanisms of brain aging; however, the specific connection between gut microbiota and aging remains unclear. The abnormal expression and mutation of proteins belonging to the P4-ATPase family, including Atp11b, results in a variety of neurological diseases. The results of our analysis demonstrate that there was a shift in the abundance of certain gut microbiota in Atp11b-knockout (KO) mice. Specifically, there was an increase in pro-inflammatory bacteria that accelerate aging and a decrease in probiotics that delay aging. Consequently, an enhanced oxidative stress response was observed, which was characterized by a reduction in the superoxide dismutase (SOD) activity and an increase in malondialdehyde (MDA) and reactive oxygen species (ROS) levels. In addition, our data demonstrate that there was a decrease in the number of cells in the dentate gyrus (DG) region of the hippocampus, and aggravation of aging-related pathological features such as senescence β-galactosidase (SA-β-Gal), p-HistoneH2AX (Ser139), and p16INK4. Moreover, KO mice show typical aging-associated behavior, such as memory impairment and slow pain perception. Taken together, we demonstrate a possible mechanism of aging induced by gut microbiota in Atp11b-KO mice, which provides a novel perspective for the treatment of aging through the microbiota-gut-brain axis.
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Affiliation(s)
- Cuiping Liu
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
| | - Shibo Zhang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
| | - Hongwei Shi
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
| | - Haicong Zhou
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
| | - Junyi Zhuang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
| | - Yiyang Cao
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
| | - Natalie Ward
- Banner Ocotillo Medical Center, 1405 S Alma School Rd, Chandler, AZ 85286, USA;
| | - Jiao Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai 200444, China; (C.L.); (S.Z.); (H.S.); (H.Z.); (J.Z.); (Y.C.)
- Correspondence: ; Tel./Fax: +86-21-66-132-512
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7
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Pater JA, Penney C, O'Rielly DD, Griffin A, Kamal L, Brownstein Z, Vona B, Vinkler C, Shohat M, Barel O, French CR, Singh S, Werdyani S, Burt T, Abdelfatah N, Houston J, Doucette LP, Squires J, Glaser F, Roslin NM, Vincent D, Marquis P, Woodland G, Benoukraf T, Hawkey-Noble A, Avraham KB, Stanton SG, Young TL. Autosomal dominant non-syndromic hearing loss maps to DFNA33 (13q34) and co-segregates with splice and frameshift variants in ATP11A, a phospholipid flippase gene. Hum Genet 2022; 141:431-444. [PMID: 35278131 PMCID: PMC9035003 DOI: 10.1007/s00439-022-02444-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 02/22/2022] [Indexed: 11/20/2022]
Abstract
Sequencing exomes/genomes have been successful for identifying recessive genes; however, discovery of dominant genes including deafness genes (DFNA) remains challenging. We report a new DFNA gene, ATP11A, in a Newfoundland family with a variable form of bilateral sensorineural hearing loss (SNHL). Genome-wide SNP genotyping linked SNHL to DFNA33 (LOD = 4.77), a locus on 13q34 previously mapped in a German family with variable SNHL. Whole-genome sequencing identified 51 unremarkable positional variants on 13q34. Continuous clinical ascertainment identified several key recombination events and reduced the disease interval to 769 kb, excluding all but one variant. ATP11A (NC_000013.11: chr13:113534963G>A) is a novel variant predicted to be a cryptic donor splice site. RNA studies verified in silico predictions, revealing the retention of 153 bp of intron in the 3' UTR of several ATP11A isoforms. Two unresolved families from Israel were subsequently identified with a similar, variable form of SNHL and a novel duplication (NM_032189.3:c.3322_3327+2dupGTCCAGGT) in exon 28 of ATP11A extended exon 28 by 8 bp, leading to a frameshift and premature stop codon (p.Asn1110Valfs43Ter). ATP11A is a type of P4-ATPase that transports (flip) phospholipids from the outer to inner leaflet of cell membranes to maintain asymmetry. Haploinsufficiency of ATP11A, the phospholipid flippase that specially transports phosphatidylserine (PS) and phosphatidylethanolamine (PE), could leave cells with PS/PE at the extracellular side vulnerable to phagocytic degradation. Given that surface PS can be pharmaceutically targeted, hearing loss due to ATP11A could potentially be treated. It is also likely that ATP11A is the gene underlying DFNA33.
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Affiliation(s)
- Justin A Pater
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Cindy Penney
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
- Centre for Translational Genomics, Memorial University, 300 Prince Phillip Dr., St. John's, NL, Canada
| | - Darren D O'Rielly
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
- Centre for Translational Genomics, Memorial University, 300 Prince Phillip Dr., St. John's, NL, Canada
| | - Anne Griffin
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Lara Kamal
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Zippora Brownstein
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Barbara Vona
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Chana Vinkler
- Institute of Medical Genetics, Wolfson Medical Center, 58100, Holon, Israel
| | - Mordechai Shohat
- Bioinformatic Center, Cancer Research Institute, The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ortal Barel
- Bioinformatic Center, Cancer Research Institute, The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Curtis R French
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Sushma Singh
- Communication Sciences and Disorders, Elborn College, Western University, 1201 Western Road, London, ON, Canada
| | - Salem Werdyani
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Taylor Burt
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Nelly Abdelfatah
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Jim Houston
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Lance P Doucette
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Jessica Squires
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Fabian Glaser
- The Lorry I. Lokey Center for Life Sciences and Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Nicole M Roslin
- The Centre for Applied Genomics, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, 686 Bay Street, Toronto, ON, Canada
| | - Daniel Vincent
- Genome Quebec Innovation Centre, McGill University, 740 Dr. Penfield Avenue, Montreal, QC, Canada
| | - Pascale Marquis
- Canadian Centre for Computational Genomics, McGill University and Genome Quebec Innovation Center, 740 Dr. Penfield Avenue, Montreal, QC, Canada
| | - Geoffrey Woodland
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Touati Benoukraf
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Alexia Hawkey-Noble
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Susan G Stanton
- Communication Sciences and Disorders, Elborn College, Western University, 1201 Western Road, London, ON, Canada
| | - Terry-Lynn Young
- Faculty of Medicine, Memorial University, 300 Prince Phillip Drive, St. John's, NL, Canada.
- Centre for Translational Genomics, Memorial University, 300 Prince Phillip Dr., St. John's, NL, Canada.
- Communication Sciences and Disorders, Elborn College, Western University, 1201 Western Road, London, ON, Canada.
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8
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Narishige Y, Yaoita H, Shibuya M, Ikeda M, Kodama K, Kawahima A, Okubo Y, Endo W, Inui T, Togashi N, Tanaka S, Kobayashi Y, Onuma A, Takayama J, Tamiya G, Kikuchi A, Kure S, Haginoya K. Two Siblings with Cerebellar Ataxia, Mental Retardation, and Disequilibrium Syndrome 4 and a Novel Variant of ATP8A2. TOHOKU J EXP MED 2022; 256:321-326. [PMID: 35321980 DOI: 10.1620/tjem.2022.j010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Yuta Narishige
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Hisao Yaoita
- Department of Pediatrics, Tohoku University School of Medicine
| | - Moriei Shibuya
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Miki Ikeda
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Kaori Kodama
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | | | - Yukimune Okubo
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Wakaba Endo
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Takehiko Inui
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Noriko Togashi
- Department of Pediatric Neurology, Miyagi Children's Hospital
| | - Soichiro Tanaka
- Department of Pediatric Neurology, Miyagi Children's Hospital.,Department of Pediatric Neurology, Takuto Rehabilitation Center for Children
| | - Yasuko Kobayashi
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children
| | - Akira Onuma
- Department of Pediatric Neurology, Takuto Rehabilitation Center for Children
| | - Jun Takayama
- Tohoku University Graduate School of Medicine.,Tohoku Medical Megabank Organization, Tohoku University.,Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project
| | - Gen Tamiya
- Tohoku University Graduate School of Medicine.,Tohoku Medical Megabank Organization, Tohoku University.,Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project
| | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University School of Medicine
| | - Shigeo Kure
- Department of Pediatrics, Tohoku University School of Medicine
| | - Kazuhiro Haginoya
- Department of Pediatric Neurology, Miyagi Children's Hospital.,Department of Pediatric Neurology, Takuto Rehabilitation Center for Children
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9
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Biallelic truncation variants in ATP9A are associated with a novel autosomal recessive neurodevelopmental disorder. NPJ Genom Med 2021; 6:94. [PMID: 34764295 PMCID: PMC8586153 DOI: 10.1038/s41525-021-00255-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022] Open
Abstract
Intellectual disability (ID) is a highly heterogeneous disorder with hundreds of associated genes. Despite progress in the identification of the genetic causes of ID following the introduction of high-throughput sequencing, about half of affected individuals still remain without a molecular diagnosis. Consanguineous families with affected individuals provide a unique opportunity to identify novel recessive causative genes. In this report, we describe a novel autosomal recessive neurodevelopmental disorder. We identified two consanguineous families with homozygous variants predicted to alter the splicing of ATP9A which encodes a transmembrane lipid flippase of the class II P4-ATPases. The three individuals homozygous for these putatively truncating variants presented with severe ID, motor and speech impairment, and behavioral anomalies. Consistent with a causative role of ATP9A in these patients, a previously described Atp9a−/− mouse model showed behavioral changes.
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10
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Cioffi F, Adam RHI, Bansal R, Broersen K. A Review of Oxidative Stress Products and Related Genes in Early Alzheimer's Disease. J Alzheimers Dis 2021; 83:977-1001. [PMID: 34420962 PMCID: PMC8543250 DOI: 10.3233/jad-210497] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oxidative stress is associated with the progression of Alzheimer’s disease (AD). Reactive oxygen species can modify lipids, DNA, RNA, and proteins in the brain. The products of their peroxidation and oxidation are readily detectable at incipient stages of disease. Based on these oxidation products, various biomarker-based strategies have been developed to identify oxidative stress levels in AD. Known oxidative stress-related biomarkers include lipid peroxidation products F2-isoprostanes, as well as malondialdehyde and 4-hydroxynonenal which both conjugate to specific amino acids to modify proteins, and DNA or RNA oxidation products 8-hydroxy-2’-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG), respectively. The inducible enzyme heme oxygenase type 1 (HO-1) is found to be upregulated in response to oxidative stress-related events in the AD brain. While these global biomarkers for oxidative stress are associated with early-stage AD, they generally poorly differentiate from other neurodegenerative disorders that also coincide with oxidative stress. Redox proteomics approaches provided specificity of oxidative stress-associated biomarkers to AD pathology by the identification of oxidatively damaged pathology-specific proteins. In this review, we discuss the potential combined diagnostic value of these reported biomarkers in the context of AD and discuss eight oxidative stress-related mRNA biomarkers in AD that we newly identified using a transcriptomics approach. We review these genes in the context of their reported involvement in oxidative stress regulation and specificity for AD. Further research is warranted to establish the protein levels and their functionalities as well as the molecular mechanisms by which these potential biomarkers are involved in regulation of oxidative stress levels and their potential for determination of oxidative stress and disease status of AD patients.
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Affiliation(s)
- Federica Cioffi
- Department of Nanobiophysics, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Rayan Hassan Ibrahim Adam
- Department of Nanobiophysics, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Ruchi Bansal
- Department of Medical Cell Biophysics, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands.,Department of Pharmacokinetics, Toxicology, and Targeting, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, The Netherlands
| | - Kerensa Broersen
- Department of Applied Stem Cell Technologies, Technical Medical Centre, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
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11
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Damásio J, Santos D, Morais S, Brás J, Guerreiro R, Sardoeira A, Cavaco S, Carrilho I, Barbot C, Barros J, Sequeiros J. Congenital ataxia due to novel variant in ATP8A2. Clin Genet 2021; 100:79-83. [PMID: 33682124 DOI: 10.1111/cge.13954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 01/22/2023]
Abstract
Congenital ataxias are a heterogeneous group of disorders characterized by congenital or early-onset ataxia. Here, we describe two siblings with congenital ataxia, who acquired independent gait by age 4 years. After 16 years of follow-up they presented near normal cognition, cerebellar ataxia, mild pyramidal signs, and dystonia. On exome sequencing, a novel homozygous variant (c.1580-18C > G - intron 17) in ATP8A2 was identified. A new acceptor splice site was predicted by bioinformatics tools, and functionally characterized through a minigene assay. Minigene constructs were generated by PCR-amplification of genomic sequences surrounding the variant of interest and cloning into the pCMVdi vector. Altered splicing was evaluated by expressing these constructs in HEK293T cells. The construct with the c.1580-18C > G homozygous variant produced an aberrant transcript, leading to retention of 17 bp of intron 17, by the use of an alternative acceptor splice site, resulting in a premature stop codon by insertion of four amino acids. These results allowed us to establish this as a disease-causing variant and expand ATP8A2-related disorders to include less severe forms of congenital ataxia.
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Affiliation(s)
- Joana Damásio
- UnIGENe/CGPP - Instituto de Biologia Molecular e Celular, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Serviço Neurologia, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Diana Santos
- UnIGENe/CGPP - Instituto de Biologia Molecular e Celular, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Sara Morais
- UnIGENe/CGPP - Instituto de Biologia Molecular e Celular, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - José Brás
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, USA.,Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, Michigan, USA
| | - Rita Guerreiro
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, Michigan, USA.,Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, Michigan, USA
| | - Ana Sardoeira
- Serviço Neurologia, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Sara Cavaco
- Unidade Neuropsicologia, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Inês Carrilho
- Unidade Neurologia Pediátrica, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Clara Barbot
- UnIGENe/CGPP - Instituto de Biologia Molecular e Celular, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - José Barros
- Serviço Neurologia, Centro Hospitalar Universitário do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Jorge Sequeiros
- UnIGENe/CGPP - Instituto de Biologia Molecular e Celular, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
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12
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Heidari E, Harrison AN, Jafarinia E, Tavasoli AR, Almadani N, Molday RS, Garshasbi M. Novel variants in critical domains of ATP8A2 and expansion of clinical spectrum. Hum Mutat 2021; 42:491-497. [PMID: 33565221 DOI: 10.1002/humu.24180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 01/17/2021] [Accepted: 02/07/2021] [Indexed: 12/12/2022]
Abstract
ATP8A2 is a P4-ATPase that flips phosphatidylserine across membranes to generate and maintain transmembrane phospholipid asymmetry. Loss-of-function variants cause severe neurodegenerative and developmental disorders. We have identified three ATP8A2 variants in unrelated Iranian families that cause intellectual disability, dystonia, below-average head circumference, mild optic atrophy, and developmental delay. Additionally, all the affected individuals displayed tooth abnormalities associated with defects in teeth development. Two variants (p.Asp825His and p.Met438Val) reside in critical functional domains of ATP8A2. These variants express at very low levels and lack ATPase activity. Inhibitor studies indicate that these variants are misfolded and degraded by the cellular proteasome. We conclude that Asp825, which coordinates with the Mg2+ ion within the ATP binding site, and Met438 are essential for the proper folding of ATP8A2 into a functional flippase. We also provide evidence on the association of tooth abnormalities with defects in ATP8A2, thereby expanding the clinical spectrum of the associated disease.
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Affiliation(s)
- Erfan Heidari
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Alexander N Harrison
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ehsan Jafarinia
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Reza Tavasoli
- Division of Pediatric Neurology, Myelin Disorders Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Navid Almadani
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Robert S Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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13
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Goddard PC, Keys KL, Mak ACY, Lee EY, Liu AK, Samedy-Bates LA, Risse-Adams O, Contreras MG, Elhawary JR, Hu D, Huntsman S, Oh SS, Salazar S, Eng C, Himes BE, White MJ, Burchard EG. Integrative genomic analysis in African American children with asthma finds three novel loci associated with lung function. Genet Epidemiol 2021; 45:190-208. [PMID: 32989782 PMCID: PMC7902343 DOI: 10.1002/gepi.22365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/21/2020] [Accepted: 09/14/2020] [Indexed: 11/06/2022]
Abstract
Bronchodilator (BD) drugs are commonly prescribed for treatment and management of obstructive lung function present with diseases such as asthma. Administration of BD medication can partially or fully restore lung function as measured by pulmonary function tests. The genetics of baseline lung function measures taken before BD medication have been extensively studied, and the genetics of the BD response itself have received some attention. However, few studies have focused on the genetics of post-BD lung function. To address this gap, we analyzed lung function phenotypes in 1103 subjects from the Study of African Americans, Asthma, Genes, and Environment, a pediatric asthma case-control cohort, using an integrative genomic analysis approach that combined genotype, locus-specific genetic ancestry, and functional annotation information. We integrated genome-wide association study (GWAS) results with an admixture mapping scan of three pulmonary function tests (forced expiratory volume in 1 s [FEV1 ], forced vital capacity [FVC], and FEV1 /FVC) taken before and after albuterol BD administration on the same subjects, yielding six traits. We identified 18 GWAS loci, and five additional loci from admixture mapping, spanning several known and novel lung function candidate genes. Most loci identified via admixture mapping exhibited wide variation in minor allele frequency across genotyped global populations. Functional fine-mapping revealed an enrichment of epigenetic annotations from peripheral blood mononuclear cells, fetal lung tissue, and lung fibroblasts. Our results point to three novel potential genetic drivers of pre- and post-BD lung function: ADAMTS1, RAD54B, and EGLN3.
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Affiliation(s)
- Pagé C. Goddard
- Department of Genetics, Stanford University, Stanford, California, USA
- Department of Medicine, University of California, San Francisco, California, USA
| | - Kevin L. Keys
- Department of Medicine, University of California, San Francisco, California, USA
- Berkeley Institute for Data Science, University of California, Berkeley, California, USA
| | - Angel C. Y. Mak
- Department of Medicine, University of California, San Francisco, California, USA
| | - Eunice Y. Lee
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, USA
| | - Amy K. Liu
- Department of Neurology, University of California, San Francisco, California, USA
| | - Lesly-Anne Samedy-Bates
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, USA
| | - Oona Risse-Adams
- Department of Medicine, University of California, San Francisco, California, USA
- Department of Biology, University of California, Santa Cruz, California, USA
| | - María G. Contreras
- Department of Medicine, University of California, San Francisco, California, USA
- Department of Biology, San Francisco State University, San Francisco, California, USA
| | - Jennifer R. Elhawary
- Department of Medicine, University of California, San Francisco, California, USA
| | - Donglei Hu
- Department of Medicine, University of California, San Francisco, California, USA
| | - Scott Huntsman
- Department of Medicine, University of California, San Francisco, California, USA
| | - Sam S. Oh
- Department of Medicine, University of California, San Francisco, California, USA
| | - Sandra Salazar
- Department of Medicine, University of California, San Francisco, California, USA
| | - Celeste Eng
- Department of Medicine, University of California, San Francisco, California, USA
| | - Blanca E. Himes
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marquitta J. White
- Department of Medicine, University of California, San Francisco, California, USA
| | - Esteban G. Burchard
- Department of Medicine, University of California, San Francisco, California, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, USA
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14
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EpiMOGA: An Epistasis Detection Method Based on a Multi-Objective Genetic Algorithm. Genes (Basel) 2021; 12:genes12020191. [PMID: 33525573 PMCID: PMC7911965 DOI: 10.3390/genes12020191] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/12/2021] [Accepted: 01/25/2021] [Indexed: 12/28/2022] Open
Abstract
In genome-wide association studies, detecting high-order epistasis is important for analyzing the occurrence of complex human diseases and explaining missing heritability. However, there are various challenges in the actual high-order epistasis detection process due to the large amount of data, “small sample size problem”, diversity of disease models, etc. This paper proposes a multi-objective genetic algorithm (EpiMOGA) for single nucleotide polymorphism (SNP) epistasis detection. The K2 score based on the Bayesian network criterion and the Gini index of the diversity of the binary classification problem were used to guide the search process of the genetic algorithm. Experiments were performed on 26 simulated datasets of different models and a real Alzheimer’s disease dataset. The results indicated that EpiMOGA was obviously superior to other related and competitive methods in both detection efficiency and accuracy, especially for small-sample-size datasets, and the performance of EpiMOGA remained stable across datasets of different disease models. At the same time, a number of SNP loci and 2-order epistasis associated with Alzheimer’s disease were identified by the EpiMOGA method, indicating that this method is capable of identifying high-order epistasis from genome-wide data and can be applied in the study of complex diseases.
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15
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Mohamadian M, Ghandil P, Naseri M, Bahrami A, Momen AA. A novel homozygous variant in an Iranian pedigree with cerebellar ataxia, mental retardation, and dysequilibrium syndrome type 4. J Clin Lab Anal 2020; 34:e23484. [PMID: 33079427 PMCID: PMC7676196 DOI: 10.1002/jcla.23484] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/12/2020] [Accepted: 06/26/2020] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Cerebellar ataxia, mental retardation, and dysequilibrium (CAMRQ) syndrome is a rare and early-onset neurodevelopmental disorder. Four subtypes of this syndrome have been identified, which are clinically and genetically different. To date, altogether 32 patients have been described with ATP8A2 mutations and phenotypic features assigned to CAMRQ type 4. Herein, three additional patients in an Iranian consanguineous family with non-progressive cerebellar ataxia, severe hypotonia, intellectual disability, dysarthria, and cerebellar atrophy have been identified. METHODS Following the thorough clinical examination, consecutive detections including chromosome karyotyping, chromosomal microarray analysis, and whole exome sequencing (WES) were performed on the proband. The sequence variants derived from WES interpreted by a standard bioinformatics pipeline. Pathogenicity assessment of candidate variant was done by in silico analysis. The familial cosegregation of the WES finding was carried out by PCR-based Sanger sequencing. RESULTS A novel homozygous missense variant (c.1339G > A, p.Gly447Arg) in the ATP8A2 gene was identified and completely segregated with the phenotype in the family. In silico analysis and structural modeling revealed that the p.G477R substitution is deleterious and induced undesired effects on the protein stability and residue distribution in the ligand-binding pocket. The novel sequence variant occurred within an extremely conserved subregion of the ATP-binding domain. CONCLUSION Our findings expand the spectrum of ATP8A2 mutations and confirm the reported genotype-phenotype correlation. These results could improve genetic counseling and prenatal diagnosis in families with clinical presentations related to CAMRQ4 syndrome.
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Affiliation(s)
- Malihe Mohamadian
- Department of Molecular Medicine, Birjand University of Medical Sciences, Birjand, Iran
| | - Pegah Ghandil
- Diabetes Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Department of Medical Genetics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohsen Naseri
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Afsane Bahrami
- Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Ali Akbar Momen
- Department of Paediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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16
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Baizabal-Carvallo JF, Cardoso F. Chorea in children: etiology, diagnostic approach and management. J Neural Transm (Vienna) 2020; 127:1323-1342. [DOI: 10.1007/s00702-020-02238-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/01/2020] [Indexed: 01/07/2023]
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17
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Affiliation(s)
- Hye-Won Shin
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroyuki Takatsu
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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18
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Guissart C, Harrison AN, Benkirane M, Oncel I, Arslan EA, Chassevent AK., Baraῆano K, Larrieu L, Iascone M, Tenconi R, Claustres M, Eroglu-Ertugrul N, Calvas P, Topaloglu H, Molday RS, Koenig M. ATP8A2-related disorders as recessive cerebellar ataxia. J Neurol 2019; 267:203-213. [DOI: 10.1007/s00415-019-09579-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/06/2019] [Accepted: 10/10/2019] [Indexed: 02/03/2023]
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19
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Choi H, Andersen JP, Molday RS. Expression and functional characterization of missense mutations in ATP8A2 linked to severe neurological disorders. Hum Mutat 2019; 40:2353-2364. [PMID: 31397519 DOI: 10.1002/humu.23889] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/30/2019] [Accepted: 08/04/2019] [Indexed: 11/09/2022]
Abstract
ATP8A2 is a P4-ATPase (adenosine triphosphate) that actively flips phosphatidylserine and phosphatidylethanolamine from the exoplasmic to the cytoplasmic leaflet of cell membranes to generate and maintain phospholipid asymmetry. Mutations in the ATP8A2 gene have been reported to cause severe autosomal recessive neurological diseases in humans characterized by intellectual disability, hypotonia, chorea, and hyperkinetic movement disorders with or without optic and cerebellar atrophy. To determine the effect of disease-associated missense mutations on ATP8A2, we expressed six variants with the accessory subunit CDC50A in HEK293T cells. The level of expression, cellular localization, and functional activity were analyzed by western blot analysis, immunofluorescence microscopy, and ATPase activity assays. Two variants (p.Ile376Met and p.Lys429Met) expressed at normal ATP8A2 levels and preferentially localized to the Golgi-recycling endosomes, but were devoid of ATPase activity. Four variants (p.Lys429Asn, pAla544Pro, p.Arg625Trp, and p.Trp702Arg) expressed poorly, localized to the endoplasmic reticulum, and lacked ATPase activity. The expression of these variants was increased twofold by the addition of the proteasome inhibitor MG132. We conclude that the p.Ile376Met and p.Lys429Met variants fold in a native-like conformation, but lack key amino acid residues required for ATP-dependent lipid transport. In contrast, the p.Lys429Asn, pAla544Pro, p.Arg625Trp, and p.Trp702Arg variants are highly misfolded and undergo rapid proteosomal degradation.
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Affiliation(s)
- Hanbin Choi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jens P Andersen
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
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20
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Phosphatidylserine flipping by the P4-ATPase ATP8A2 is electrogenic. Proc Natl Acad Sci U S A 2019; 116:16332-16337. [PMID: 31371510 DOI: 10.1073/pnas.1910211116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phospholipid flippases (P4-ATPases) utilize ATP to translocate specific phospholipids from the exoplasmic leaflet to the cytoplasmic leaflet of biological membranes, thus generating and maintaining transmembrane lipid asymmetry essential for a variety of cellular processes. P4-ATPases belong to the P-type ATPase protein family, which also encompasses the ion transporting P2-ATPases: Ca2+-ATPase, Na+,K+-ATPase, and H+,K+-ATPase. In comparison with the P2-ATPases, understanding of P4-ATPases is still very limited. The electrogenicity of P4-ATPases has not been explored, and it is not known whether lipid transfer between membrane bilayer leaflets can lead to displacement of charge across the membrane. A related question is whether P4-ATPases countertransport ions or other substrates in the opposite direction, similar to the P2-ATPases. Using an electrophysiological method based on solid supported membranes, we observed the generation of a transient electrical current by the mammalian P4-ATPase ATP8A2 in the presence of ATP and the negatively charged lipid substrate phosphatidylserine, whereas only a diminutive current was generated with the lipid substrate phosphatidylethanolamine, which carries no or little charge under the conditions of the measurement. The current transient seen with phosphatidylserine was abolished by the mutation E198Q, which blocks dephosphorylation. Likewise, mutation I364M, which causes the neurological disorder cerebellar ataxia, mental retardation, and disequilibrium (CAMRQ) syndrome, strongly interfered with the electrogenic lipid translocation. It is concluded that the electrogenicity is associated with a step in the ATPase reaction cycle directly involved in translocation of the lipid. These measurements also showed that no charged substrate is being countertransported, thereby distinguishing the P4-ATPase from P2-ATPases.
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21
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Mutations in the Neuronal Vesicular SNARE VAMP2 Affect Synaptic Membrane Fusion and Impair Human Neurodevelopment. Am J Hum Genet 2019; 104:721-730. [PMID: 30929742 PMCID: PMC6451933 DOI: 10.1016/j.ajhg.2019.02.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/13/2019] [Indexed: 01/21/2023] Open
Abstract
VAMP2 encodes the vesicular SNARE protein VAMP2 (also called synaptobrevin-2). Together with its partners syntaxin-1A and synaptosomal-associated protein 25 (SNAP25), VAMP2 mediates fusion of synaptic vesicles to release neurotransmitters. VAMP2 is essential for vesicular exocytosis and activity-dependent neurotransmitter release. Here, we report five heterozygous de novo mutations in VAMP2 in unrelated individuals presenting with a neurodevelopmental disorder characterized by axial hypotonia (which had been present since birth), intellectual disability, and autistic features. In total, we identified two single-amino-acid deletions and three non-synonymous variants affecting conserved residues within the C terminus of the VAMP2 SNARE motif. Affected individuals carrying de novo non-synonymous variants involving the C-terminal region presented a more severe phenotype with additional neurological features, including central visual impairment, hyperkinetic movement disorder, and epilepsy or electroencephalography abnormalities. Reconstituted fusion involving a lipid-mixing assay indicated impairment in vesicle fusion as one of the possible associated disease mechanisms. The genetic synaptopathy caused by VAMP2 de novo mutations highlights the key roles of this gene in human brain development and function.
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22
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Zhang S, Liu W, Yang Y, Sun K, Li S, Xu H, Yang M, Zhang L, Zhu X. TMEM30A deficiency in endothelial cells impairs cell proliferation and angiogenesis. J Cell Sci 2019; 132:jcs.225052. [PMID: 30814335 DOI: 10.1242/jcs.225052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 02/19/2019] [Indexed: 12/23/2022] Open
Abstract
Phosphatidylserine (PS) asymmetry in the eukaryotic cell membrane is maintained by a group of proteins belonging to the P4-ATPase family, namely, PS flippases. The folding and transporting of P4-ATPases to their cellular destination requires a β-subunit member of the TMEM30 protein family. Loss of Tmem30a has been shown to cause multiple disease conditions. However, its roles in vascular development have not been elucidated. Here, we show that TMEM30A plays critical roles in retinal vascular angiogenesis, which is a fundamental process in vascular development. Our data indicate that knockdown of TMEM30A in primary human retinal endothelial cells led to reduced tube formation. In mice, endothelial cell (EC)-specific deletion of Tmem30a led to retarded retinal vascular development with a hyperpruned vascular network as well as blunted-end, aneurysm-like tip ECs with fewer filopodia at the vascular front and a reduced number of tip cells. Deletion of Tmem30a also impaired vessel barrier integrity. Mechanistically, deletion of TMEM30A caused reduced EC proliferation by inhibiting VEGF-induced signaling. Our findings reveal essential roles of TMEM30A in angiogenesis, providing a potential therapeutic target.
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Affiliation(s)
- Shanshan Zhang
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.,Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, Sichuan, China
| | - Wenjing Liu
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
| | - Yeming Yang
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
| | - Kuanxiang Sun
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.,Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, Sichuan, China
| | - Shujin Li
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
| | - Huijuan Xu
- Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, Sichuan, China
| | - Mu Yang
- Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, Sichuan, China
| | - Lin Zhang
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China .,Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, Sichuan, China
| | - Xianjun Zhu
- Institute of Laboratory Medicine, Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China .,Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, 610072, China; Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, Sichuan, China.,Department of Ophthalmology, Shangqiu First People's Hospital, Shangqiu, Henan, 476000, China.,Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610212, China
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23
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Mikkelsen SA, Mogensen LS, Vilsen B, Molday RS, Vestergaard AL, Andersen JP. Asparagine 905 of the mammalian phospholipid flippase ATP8A2 is essential for lipid substrate-induced activation of ATP8A2 dephosphorylation. J Biol Chem 2019; 294:5970-5979. [PMID: 30760526 DOI: 10.1074/jbc.ra118.007240] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/11/2019] [Indexed: 01/11/2023] Open
Abstract
The P-type ATPase protein family includes, in addition to ion pumps such as Ca2+-ATPase and Na+,K+-ATPase, also phospholipid flippases that transfer phospholipids between membrane leaflets. P-type ATPase ion pumps translocate their substrates occluded between helices in the center of the transmembrane part of the protein. The large size of the lipid substrate has stimulated speculation that flippases use a different transport mechanism. Information on the functional importance of the most centrally located helices M5 and M6 in the transmembrane domain of flippases has, however, been sparse. Using mutagenesis, we examined the entire M5-M6 region of the mammalian flippase ATP8A2 to elucidate its possible function in the lipid transport mechanism. This mutational screen yielded an informative map assigning important roles in the interaction with the lipid substrate to only a few M5-M6 residues. The M6 asparagine Asn-905 stood out as being essential for the lipid substrate-induced dephosphorylation. The mutants N905A/D/E/H/L/Q/R all displayed very low activities and a dramatic insensitivity to the lipid substrate. Strikingly, Asn-905 aligns with key ion-binding residues of P-type ATPase ion pumps, and N905D was recently identified as one of the mutations causing the neurological disorder cerebellar ataxia, mental retardation, and disequilibrium (CAMRQ) syndrome. Moreover, the effects of substitutions to the adjacent residue Val-906 (i.e. V906A/E/F/L/Q/S) suggest that the lipid substrate approaches Val-906 during the translocation. These results favor a flippase mechanism with strong resemblance to the ion pumps, despite a location of the translocation pathway in the periphery of the transmembrane part of the flippase protein.
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Affiliation(s)
- Stine A Mikkelsen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Louise S Mogensen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Bente Vilsen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia V5Z 3N9, Canada
| | - Anna L Vestergaard
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jens Peter Andersen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.
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24
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Yang Y, Liu W, Sun K, Jiang L, Zhu X. Tmem30a deficiency leads to retinal rod bipolar cell degeneration. J Neurochem 2019; 148:400-412. [PMID: 30548540 DOI: 10.1111/jnc.14643] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 11/09/2018] [Accepted: 12/02/2018] [Indexed: 12/13/2022]
Abstract
Phospholipids are asymmetrically distributed across the mammalian plasma membrane, with phosphatidylserine (PS) and phosphatidylethanolamine concentrated in the cytoplasmic leaflet of the membrane bilayer and phosphatidylcholine in the exoplasmic leaflet. This asymmetric distribution is dependent on a group of P4 ATPases called PS flippases. The proper transport and function of PS flippases require a β-subunit transmembrane protein 30A (TMEM30A). Disruption of PS flippases leads to several human diseases. Tmem30a is essential for photoreceptor survival. However, the roles of Tmem30a in the retinal rod bipolar cells (RBC) remain elusive. To investigate the role of Tmem30a in the RBCs, we generated a RBC-specific Tmem30a knockout (cKO) mouse model using PCP2-Cre line. The Tmem30a cKO mice exhibited defect in RBC function and progressive RBC death. PKCα staining of retinal cryosections from cKO mice revealed a remarkable dendritic sprouting of rod bipolar cells during the early degenerative process. Immunostaining analysis of PSD95 and mGluT6 expression demonstrated that rod bipolar cells in Tmem30a cKO retinas exhibited aberrant dendritic sprouting as a result of impaired synaptic efficacy, which implied a crucial role for Tmem30a in synaptic transmission in the retina. In addition, loss of Tmem30a led to reactive gliosis with increased expression of glial fibrillary acidic protein and CD68. TUNEL staining suggested that apoptotic cell death occurred in the retinal inner nuclear layer (INL). Our data show that loss of Tmem30a in RBCs results in dendritic sprouting of rod bipolar cells, increased astrogliosis and RBC death. Taken together, our studies demonstrate an essential role for Tmem30a in the retinal bipolar cells. Cover Image for this issue: doi: 10.1111/jnc.14492.
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Affiliation(s)
- Yeming Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Wenjing Liu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Kuanxiang Sun
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Li Jiang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, China
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Institute of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China.,Department of Ophthalmology, Shangqiu First Municipal People's Hospital, Shangqiu, Henan, China.,Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, China.,Chinese Academy of Sciences Sichuan Translational Medicine Hospital, Chengdu, China
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25
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García-Cazorla À, Saudubray JM. Cellular neurometabolism: a tentative to connect cell biology and metabolism in neurology. J Inherit Metab Dis 2018; 41:1043-1054. [PMID: 30014209 PMCID: PMC6326994 DOI: 10.1007/s10545-018-0226-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/12/2018] [Accepted: 06/26/2018] [Indexed: 12/19/2022]
Abstract
It has become increasingly evident that inborn errors of metabolism (IEMs) are particularly prevalent as diseases of the nervous system and that a broader, more inclusive definition of IEM is necessary. In fact, as long as biochemistry is involved, any kind of monogenic disease can become an IEM. This new, extended definition includes new categories and mechanisms, and as a general trend will go beyond a single biochemical pathway and/or organelle, and will appear as a connection of multiple crossroads in a system biology approach.From one side, a simplified and updated classification of IEM is presented that mixes elements from the diagnostic approach with pathophysiological considerations into three large categories based on the size of molecules ("small and simple" or "large and complex") and their implication in energy metabolism. But from another side, whatever their size, metabolites involved in IEM may behave in the brain as signalling molecules, structural components and fuels, and many metabolites have more than one role. Neurometabolism is becoming more relevant, not only in relation to these new categories of diseases but also as a necessary way to explain the mechanisms of brain damage in classically defined categories of IEM. Brain metabolism, which has been largely disregarded in the traditional approach to investigating and treating neurological diseases, is a major clue and probably the next imminent "revolution" in neurology and neuroscience. Biochemistry (metabolism) and cell neurobiology need to meet. Additionally, the brain should be studied as a system (connecting different levels of complexity).
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Affiliation(s)
- Àngels García-Cazorla
- Neurometabolic Unit and Synaptic Metabolism Lab (Department of Neurology), Institut Pediàtric de Recerca. Hospital Sant Joan de Déu and CIBERER (ISCIII), Barcelona, Spain
| | - Jean-Marie Saudubray
- Department of Neurology, Neurometabolic Unit, Hopital Pitié Salpétrière, 47-83 Boulevard de l’Hopital, 75651 Paris Cedex 13, France
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26
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Wang J, Molday LL, Hii T, Coleman JA, Wen T, Andersen JP, Molday RS. Proteomic Analysis and Functional Characterization of P4-ATPase Phospholipid Flippases from Murine Tissues. Sci Rep 2018; 8:10795. [PMID: 30018401 PMCID: PMC6050252 DOI: 10.1038/s41598-018-29108-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/05/2018] [Indexed: 01/31/2023] Open
Abstract
P4-ATPases are a subfamily of P-type ATPases that flip phospholipids across membranes to generate lipid asymmetry, a property vital to many cellular processes. Mutations in several P4-ATPases have been linked to severe neurodegenerative and metabolic disorders. Most P4-ATPases associate with one of three accessory subunit isoforms known as CDC50A (TMEM30A), CDC50B (TMEM30B), and CDC50C (TMEM30C). To identify P4-ATPases that associate with CDC50A, in vivo, and determine their tissue distribution, we isolated P4-ATPases-CDC50A complexes from retina, brain, liver, testes, and kidney on a CDC50A immunoaffinity column and identified and quantified P4-ATPases from their tryptic peptides by mass spectrometry. Of the 12 P4-ATPase that associate with CDC50 subunits, 10 P4-ATPases were detected. Four P4-ATPases (ATP8A1, ATP11A, ATP11B, ATP11C) were present in all five tissues. ATP10D was found in low amounts in liver, brain, testes, and kidney, and ATP8A2 was present in significant amounts in retina, brain, and testes. ATP8B1 was detected only in liver, ATP8B3 and ATP10A only in testes, and ATP8B2 primarily in brain. We also show that ATP11A, ATP11B and ATP11C, like ATP8A1 and ATP8A2, selectively flip phosphatidylserine and phosphatidylethanolamine across membranes. These studies provide new insight into the tissue distribution, relative abundance, subunit interactions and substrate specificity of P4-ATPase-CDC50A complexes.
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Affiliation(s)
- Jiao Wang
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- Laboratory of Molecular Neural Biology, Institute of Systems Biology, School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Theresa Hii
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Jonathan A Coleman
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Tieqiao Wen
- Laboratory of Molecular Neural Biology, Institute of Systems Biology, School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Jens P Andersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada.
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27
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McMillan HJ, Telegrafi A, Singleton A, Cho MT, Lelli D, Lynn FC, Griffin J, Asamoah A, Rinne T, Erasmus CE, Koolen DA, Haaxma CA, Keren B, Doummar D, Mignot C, Thompson I, Velsher L, Dehghani M, Vahidi Mehrjardi MY, Maroofian R, Tchan M, Simons C, Christodoulou J, Martín-Hernández E, Guillen Sacoto MJ, Henderson LB, McLaughlin H, Molday LL, Molday RS, Yoon G. Recessive mutations in ATP8A2 cause severe hypotonia, cognitive impairment, hyperkinetic movement disorders and progressive optic atrophy. Orphanet J Rare Dis 2018; 13:86. [PMID: 30012219 PMCID: PMC6048855 DOI: 10.1186/s13023-018-0825-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 05/15/2018] [Indexed: 12/30/2022] Open
Abstract
Background ATP8A2 mutations have recently been described in several patients with severe, early-onset hypotonia and cognitive impairment. The aim of our study was to characterize the clinical phenotype of patients with ATP8A2 mutations. Methods An observational study was conducted at multiple diagnostic centres. Clinical data is presented from 9 unreported and 2 previously reported patients with ATP8A2 mutations. We compare their features with 3 additional patients that have been previously reported in the medical literature. Results Eleven patients with biallelic ATP8A2 mutations were identified, with a mean age of 9.4 years (range 2.5–28 years). All patients with ATP8A2 mutations (100%) demonstrated developmental delay, severe hypotonia and movement disorders, specifically chorea or choreoathetosis (100%), dystonia (27%) and facial dyskinesia (18%). Optic atrophy was observed in 78% of patients for whom funduscopic examination was performed. Symptom onset in all (100%) was noted before 6 months of age, with 70% having symptoms noted at birth. Feeding difficulties were common (91%) although most patients were able to tolerate pureed or thickened feeds, and 3 patients required gastrostomy tube insertion. MRI of the brain was normal in 50% of the patients. A smaller proportion was noted to have mild cortical atrophy (30%), delayed myelination (20%) and/or hypoplastic optic nerves (20%). Functional studies were performed on differentiated induced pluripotent cells from one child, which confirmed a decrease in ATP8A2 expression compared to control cells. Conclusions ATP8A2 gene mutations have emerged as the cause of a novel neurological phenotype characterized by global developmental delays, severe hypotonia and hyperkinetic movement disorders, the latter being an important distinguishing feature. Optic atrophy is common and may only become apparent in the first few years of life, necessitating repeat ophthalmologic evaluation in older children. Early recognition of the cardinal features of this condition will facilitate diagnosis of this complex neurologic disorder. Electronic supplementary material The online version of this article (10.1186/s13023-018-0825-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hugh J McMillan
- Division of Neurology, Department of Pediatrics, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
| | | | | | | | - Daniel Lelli
- Division of Neurology, Department of Medicine, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada
| | - Francis C Lynn
- Diabetes Research Program, Child and Family Research Institute, Vancouver, BC, Canada.,Department of Surgery and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Julie Griffin
- Weisskopf Child Evaluation Center, Department of Pediatrics, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Alexander Asamoah
- Weisskopf Child Evaluation Center, Department of Pediatrics, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Tuula Rinne
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Corrie E Erasmus
- Department of Neurology, Donders Center of Neuroscience, Radboud University Medical Center, Nijmegen, The Netherlands
| | - David A Koolen
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Charlotte A Haaxma
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Boris Keren
- Assistance Publique Hôpitaux de Paris, Département de Génétique, Groupe Hospitalier, Pitié-Salpêtrière, Paris, France
| | - Diane Doummar
- Service de Neuropédiatrie, Hôpital Armand-Trousseau, Paris, France
| | - Cyril Mignot
- Assistance Publique Hôpitaux de Paris, Département de Génétique, Groupe Hospitalier, Pitié-Salpêtrière, Paris, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, GH Pitié Salpêtrière, Paris, France.,Groupe de Recherche Clinique UPMC Déficience Intellectuelle de Causes Rares et Autisme GH Pitié-Salpêtrière, Paris, France
| | - Islay Thompson
- Genetics Program, North York General Hospital, Toronto, ON, Canada
| | - Lea Velsher
- Genetics Program, North York General Hospital, Toronto, ON, Canada
| | - Mohammadreza Dehghani
- Medical Genetics Research Centre, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Reproductive Sciences Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Yahya Vahidi Mehrjardi
- Reproductive Sciences Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Diabetes Research Centre, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Reza Maroofian
- Human Genetics Research Centre, Molecular and Clinical Sciences Institute, St George's University of London, London, UK
| | - Michel Tchan
- Department of Genetic Medicine, Westmead Hospital, Westmead, NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Cas Simons
- Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia
| | - John Christodoulou
- Neurodevelopmental Genomics Research Group, Murdoch Childrens Research Institute and Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Elena Martín-Hernández
- Unidad de Enfermedades Mitocondriales-Metabólicas Hereditarias, Servicio de Pediatría Hospital Universitario 12 de Octubre, Universidad Complutense de Madrid, Madrid, Spain
| | | | | | | | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.,Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, BC, Canada
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.,Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, BC, Canada
| | - Grace Yoon
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, ON, M5G 1X8, Canada. .,Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
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28
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Li N, Yang Y, Liang C, Qiu Q, Pan C, Li M, Yang S, Chen L, Zhu X, Hu Y. Tmem30a Plays Critical Roles in Ensuring the Survival of Hematopoietic Cells and Leukemia Cells in Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:1457-1468. [PMID: 29574182 DOI: 10.1016/j.ajpath.2018.02.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/03/2018] [Accepted: 02/27/2018] [Indexed: 02/05/2023]
Abstract
The fundamental structure of eukaryotic cell plasma membrane is the phospholipid bilayer, which contains four major phospholipids. These phospholipids are asymmetrically distributed between the outer and inner leaflets. P4-ATPase flippase complexes play essential roles in ensuring this asymmetry. We found that conditional deletion of Tmem30a, the β subunit of P4-ATPase flippase complex, caused pancytopenia in mice. Tmem30a deficiency resulted in depletion of lineage-committed blood cells in the peripheral blood, spleen, and bone marrow. Ablation of Tmem30a also caused the depletion of hematopoietic stem cells (HSCs). HSC RNA sequencing results revealed that multiple biological processes and signal pathways were involved in the event, including mammalian target of rapamycin signaling, genes for HSC stemness, and genes responding to interferons. Our results also revealed that targeting Tmem30a signaling had therapeutic utility in BCR/ABL1-induced chronic myeloid leukemia.
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Affiliation(s)
- Ning Li
- Department of Thyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China; State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yeming Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Cailing Liang
- Department of Thyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China; State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Qiang Qiu
- Department of Thyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China; State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Cong Pan
- Department of Thyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China; State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Mengyuan Li
- Department of Thyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China; State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Shengyong Yang
- State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Lijuan Chen
- State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; Chengdu Institute of Biology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China.
| | - Yiguo Hu
- Department of Thyroid Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, China; State Key Laboratory of Biotherapy & Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
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29
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Alsahli S, Alrifai MT, Al Tala S, Mutairi FA, Alfadhel M. Further Delineation of the Clinical Phenotype of Cerebellar Ataxia, Mental Retardation, and Disequilibrium Syndrome Type 4. J Cent Nerv Syst Dis 2018. [PMID: 29531481 PMCID: PMC5843099 DOI: 10.1177/1179573518759682] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Cerebellar ataxia, mental retardation, and disequilibrium syndrome (CAMRQ) is a heterogeneous group of genetic disorders that have been grouped by shared clinical features; all of these features are transmitted via an autosomal recessive mechanism. Four variants of this syndrome have been identified so far, and each one differs in terms of both clinical and genotypical features. CAMRQ4 is a rare genetic disorder characterized by mental retardation, ataxia or an inability to walk, dysarthria and, in some patients, quadrupedal gait. Methods We investigated three Saudi families with CAMRQ4. Blood samples were collected from the affected patients, their parents, and healthy siblings. DNA was extracted from whole blood, and whole-exome sequencing was performed. Findings were confirmed by segregation analysis, which was performed on other family members. Results Thus far, 17 patients have been affected by CAMRQ4. Genetic analysis of all patients, including our current patients, showed a mutation in the aminophospholipid transporter, class I, type 8A, member 2 gene (ATP8A2). A series of common phenotypical features have been reported in these patients, with few exceptions. Ataxia, mental retardation, and hypotonia were present in all patients, consanguinity in 90% and abnormal movements in 50%. Moreover, 40% achieved ambulation at least once in their lifetime, 40% had microcephaly, whereas 30% were mute. Magnetic resonance imaging (MRI) of the brain was normal in 60% of patients. Conclusions We described the largest cohort of patients with CAMRQ4 syndrome and identified three novel mutations. CAMRQ4 syndrome should be suspected in patients presenting with ataxia, intellectual disability, hypotonia, microcephaly, choreoathetoid movements, ophthalmoplegia, and global developmental delay, even if brain MRI appears normal.
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Affiliation(s)
- Saud Alsahli
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Muhammad Talal Alrifai
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), Division of Neurology, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Saeed Al Tala
- Division of Genetics, Department of Pediatrics, Armed Forces Hospital, Khamis Mushayt, Saudi Arabia
| | - Fuad Al Mutairi
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | - Majid Alfadhel
- King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC), Division of Genetics, Department of Pediatrics, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs (MNGHA), Riyadh, Saudi Arabia
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30
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Gantzel RH, Mogensen LS, Mikkelsen SA, Vilsen B, Molday RS, Vestergaard AL, Andersen JP. Disease mutations reveal residues critical to the interaction of P4-ATPases with lipid substrates. Sci Rep 2017; 7:10418. [PMID: 28874751 PMCID: PMC5585164 DOI: 10.1038/s41598-017-10741-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/14/2017] [Indexed: 02/08/2023] Open
Abstract
Phospholipid flippases (P4-ATPases) translocate specific phospholipids from the exoplasmic to the cytoplasmic leaflet of membranes. While there is good evidence that the overall molecular structure of flippases is similar to that of P-type ATPase ion-pumps, the transport pathway for the “giant” lipid substrate has not been determined. ATP8A2 is a flippase with selectivity toward phosphatidylserine (PS), possessing a net negatively charged head group, whereas ATP8B1 exhibits selectivity toward the electrically neutral phosphatidylcholine (PC). Setting out to elucidate the functional consequences of flippase disease mutations, we have identified residues of ATP8A2 that are critical to the interaction with the lipid substrate during the translocation process. Among the residues pinpointed are I91 and L308, which are positioned near proposed translocation routes through the protein. In addition we pinpoint two juxtaposed oppositely charged residues, E897 and R898, in the exoplasmic loop between transmembrane helices 5 and 6. The glutamate is conserved between PS and PC flippases, whereas the arginine is replaced by a negatively charged aspartate in ATP8B1. Our mutational analysis suggests that the glutamate repels the PS head group, whereas the arginine minimizes this repulsion in ATP8A2, thereby contributing to control the entry of the phospholipid substrate into the translocation pathway.
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Affiliation(s)
- Rasmus H Gantzel
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark
| | - Louise S Mogensen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark
| | - Stine A Mikkelsen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark
| | - Bente Vilsen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada.,Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Anna L Vestergaard
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark.,Laboratory for Immuno-Endocrinology, Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen N, Denmark
| | - Jens P Andersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark.
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31
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Zhang L, Yang Y, Li S, Zhang S, Zhu X, Tai Z, Yang M, Liu Y, Guo X, Chen B, Jiang Z, Lu F, Zhu X. Loss of Tmem30a leads to photoreceptor degeneration. Sci Rep 2017; 7:9296. [PMID: 28839191 PMCID: PMC5571223 DOI: 10.1038/s41598-017-09506-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/26/2017] [Indexed: 12/16/2022] Open
Abstract
Phosphatidylserine (PS) is asymmetrically distributed between the outer and inner leaflets of the plasma membrane in eukaryotic cells. PS asymmetry on the plasma membrane depends on the activities of P4-ATPases, and disruption of PS distribution can lead to various disease conditions. Folding and transporting of P4-ATPases to their cellular destination requires the β subunit TMEM30A proteins. However, the in vivo functions of Tmem30a remain unknown. To this end, we generated retinal-specific Tmem30a-knockout mice to investigate its roles in vivo for the first time. Our data demonstrated that loss of Tmem30a in mouse cone cells leads to mislocalization of cone opsin, loss of photopic electroretinogram (ERG) responses and loss of cone cells. Mechanistically, Tmem30a-mutant mouse embryonic fibroblasts (MEFs) exhibited diminished PS flippase activity and increased exposure of PS on the cell surface. The broad loss of Tmem30a in adult mice led to a reduced scotopic photoresponse, mislocalization of ATP8A2 to the inner segment and cell body, and increased apoptosis in the retina. Our data demonstrated novel essential roles of Tmem30a in the retina.
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Affiliation(s)
- Lin Zhang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China
| | - Yeming Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China
| | - Shujin Li
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.,Chengdu Institute of Biology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Shanshan Zhang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China
| | - Xiong Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China
| | - Zhengfu Tai
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.,Chengdu Institute of Biology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Mu Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.,Chengdu Institute of Biology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Yuqing Liu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China
| | - Xinzheng Guo
- Department of Ophthalmology, Yale University School of Medicine, New Haven, CT, USA
| | - Bo Chen
- Department of Ophthalmology, Yale University School of Medicine, New Haven, CT, USA
| | - Zhilin Jiang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China
| | - Fang Lu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China. .,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China.
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study and School of Medicine, Hospital of the University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China. .,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, 610072, China. .,Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China. .,Chengdu Institute of Biology, Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China.
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