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Alkahtani S, Alkahtane AA, Stournaras C, Alarifi S. Chorein sensitive microtubule organization in tumor cells. PeerJ 2023; 11:e16074. [PMID: 37744224 PMCID: PMC10517657 DOI: 10.7717/peerj.16074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 08/20/2023] [Indexed: 09/26/2023] Open
Abstract
Background The purpose of this study is to analyzed the involvement of chorein in microtubules organization of three types of malignant; rhabdomyosarcoma tumor cells (ZF), rhabdomyosarcoma cells (RH30), and rhabdomyosarcoma cells (RD). ZF are expressing high chorein levels. Previous studies revealed that chorein protein silencing in ZF tumor cells persuaded apoptotic response followed by cell death. In addition, in numerous malignant and non-malignant cells this protein regulates actin cytoskeleton structure and cellular signaling. However, the function of chorein protein in microtubular organization is yet to be established. Methods In a current research study, we analyzed the involvement of chorein in microtubules organization by using three types of malignant rhabdomyosarcoma cells. We have applied confocal laser-scanning microscopy to analyze microtubules structure and RT-PCR to examine cytoskeletal gene transcription. Results We report here that in rhabdomyosarcoma cells (RH30), chorein silencing induced disarrangement of microtubular network. This was documented by laser scanning microscopy and further quantified by FACS analysis. Interestingly and in agreement with previous reports, tubulin gene transcription in RH cells was unchanged upon silencing of chorein protein. Equally, confocal analysis showed minor disordered microtubules organization with evidently weakened staining in rhabdomyosarcoma cells (RD and ZF) after silencing of chorein protein. Conclusion These results disclose that chorein silencing induces considerable structural disorganization of tubulin network in RH30 human rhabdomyosarcoma tumor cells. Additional studies are now needed to establish the role of chorein in regulating cytoskeleton architecture in tumor cells.
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Affiliation(s)
- Saad Alkahtani
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Abdullah A. Alkahtane
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Christos Stournaras
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Saud Alarifi
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
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2
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Chaudhari S, Ware AP, Jasti DB, Gorthi SP, Acharya LP, Bhat M, Mallya S, Satyamoorthy K. Exome sequencing of choreoacanthocytosis reveals novel mutations in VPS13A and co-mutation in modifier gene(s). Mol Genet Genomics 2023; 298:965-976. [PMID: 37209156 DOI: 10.1007/s00438-023-02032-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 05/04/2023] [Indexed: 05/22/2023]
Abstract
Choreoacanthocytosis, one of the forms of neuroacanthocytosis, is caused by mutations in vacuolar protein sorting-associated protein A (VPS13A), and is often misdiagnosed with other form of neuroacanthocytosis with discrete genetic defects. The phenotypic variations among the patients with VPS13A mutations significantly obfuscates the understanding of the disease and treatment strategies. In this study, two unrelated cases were identified, exhibiting the core phenotype of neuroacanthocytosis but with considerable clinical heterogeneity. Case 1 presented with an additional Parkinsonism phenotype, whereas seizures were evident in case 2. To decipher the genetic basis, whole exome sequencing followed by validation with Sanger sequencing was performed. A known homozygous pathogenic nonsense mutation (c.799C > T; p.R267X) in exon 11 of the VPS13A gene was identified in case 1 that resulted in a truncated protein. A novel missense mutation (c.9263T > G; p.M3088R) in exon 69 of VPS13A identified in case 2 was predicted as pathogenic. In silico analysis of the p.M3088R mutation at the C-terminus of VPS13A suggests a loss of interaction with TOMM40 and may disrupt mitochondrial localization. We also observed an increase in mitochondrial DNA copy numbers in case 2. Mutation analysis revealed benign heterozygous variants in interacting partners of VPS13A such as VAPA in case 1. Our study confirmed the cases as ChAc and identified the novel homozygous variant of VPS13A (c.9263T > G; p.M3088R) within the mutation spectrum of VPS13A-associated ChAc. Furthermore, mutations in VPS13A and co-mutations in its potential interacting partner(s) might contribute to the diverse clinical manifestations of ChAc, which requires further study.
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Affiliation(s)
- Sima Chaudhari
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Akshay Pramod Ware
- Department of Bioinformatics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Dushyanth Babu Jasti
- Department of Neurology, Kasturba Medical College, Manipal, Karnataka, 576104, India
| | - Sankar Prasad Gorthi
- Department of Neurology, Kasturba Medical College, Manipal, Karnataka, 576104, India
- Department of Neurology, Bharati Hospital and Research Center, Bharati Vidyapeeth (Deemed to be University) Medical College and Hospital, Dhankawadi, Pune, Maharashtra, 411043, India
| | - Lavanya Prakash Acharya
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Manoj Bhat
- Department of Bioinformatics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Sandeep Mallya
- Department of Bioinformatics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
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3
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Tariq K, Luikart BW. Striking a balance: PIP 2 and PIP 3 signaling in neuronal health and disease. EXPLORATION OF NEUROPROTECTIVE THERAPY 2022; 1:86-100. [PMID: 35098253 PMCID: PMC8797975 DOI: 10.37349/ent.2021.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phosphoinositides are membrane phospholipids involved in a variety of cellular processes like growth, development, metabolism, and transport. This review focuses on the maintenance of cellular homeostasis of phosphatidylinositol 4,5-bisphosphate (PIP2), and phosphatidylinositol 3,4,5-trisphosphate (PIP3). The critical balance of these PIPs is crucial for regulation of neuronal form and function. The activity of PIP2 and PIP3 can be regulated through kinases, phosphatases, phospholipases and cholesterol microdomains. PIP2 and PIP3 carry out their functions either indirectly through their effectors activating integral signaling pathways, or through direct regulation of membrane channels, transporters, and cytoskeletal proteins. Any perturbations to the balance between PIP2 and PIP3 signaling result in neurodevelopmental and neurodegenerative disorders. This review will discuss the upstream modulators and downstream effectors of the PIP2 and PIP3 signaling, in the context of neuronal health and disease.
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Affiliation(s)
- Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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4
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Eryptosis: Programmed Death of Nucleus-Free, Iron-Filled Blood Cells. Cells 2022; 11:cells11030503. [PMID: 35159312 PMCID: PMC8834305 DOI: 10.3390/cells11030503] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 12/27/2022] Open
Abstract
Human erythrocytes are organelle-free cells packaged with iron-containing hemoglobin, specializing in the transport of oxygen. With a total number of approximately 25 trillion cells per individual, the erythrocyte is the most abundant cell type not only in blood but in the whole organism. Despite their low complexity and their inability to transcriptionally upregulate antioxidant defense mechanisms, they display a relatively long life time, of 120 days. This ensures the maintenance of tissue homeostasis where the clearance of old or damaged erythrocytes is kept in balance with erythropoiesis. Whereas the regulatory mechanisms of erythropoiesis have been elucidated over decades of intensive research, the understanding of the mechanisms of erythrocyte clearance still requires some refinement. Here, we present the main pathways leading to eryptosis, the programmed death of erythrocytes, with special emphasis on Ca2+ influx, the generation of ceramide, oxidative stress, kinase activation, and iron metabolism. We also compare stress-induced erythrocyte death with erythrocyte ageing and clearance, and discuss the similarities between eryptosis and ferroptosis, the iron-dependent regulated death of nucleated blood cells. Finally, we focus on the pathologic consequences of deranged eryptosis, and discuss eryptosis in the context of different infectious diseases, e.g., viral or parasitic infections, and hematologic disorders.
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5
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Zhang XQ, Li L. Biological Function and Clinical Value of VPS13A in Pan-Cancer Based on Bioinformatics Analysis. Int J Gen Med 2021; 14:6825-6838. [PMID: 34690502 PMCID: PMC8530525 DOI: 10.2147/ijgm.s330256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022] Open
Abstract
Purpose Vacuolar protein sorting-associated protein 13A (VPS13A) has been shown to be associated with rhabdomyosarcoma, gastric cancer and ovarian cancer, but the pan cancer analysis of VPS13A is still lacking, and the bioinformatics function of VPS13A has not been studied yet. Methods We used TCGA and GEO databases to investigate the distribution, expression and prognosis of VPS13A in 33 tumors for the first time. We used TIMER2, ULCAN databases to obtain the expression differences of VPS13A in tumor tissues and corresponding normal tissues, and further obtain the gene expression in different pathological stages of tumors from the GEPIA database. Mutation types and survival analysis of VPS13A were obtained from cBioPortal database. The relationship between VPS13A and immune infiltration was explored using TIMER2. We used the String website to obtain VPS13A binding proteins and draw the protein–protein interaction network map. JVENN was used for cross analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) were used for gene enrichment analysis. Results VPS13A is highly expressed in most tumors, and gene expression is associated with prognosis in patients with tumors. The expression level of VPS13A was correlated with the infiltration depth of CD8+T cells in DLBC, LUAD, SKCM and TGCT, and was correlated with carcinoma-associated fibroblasts in BRCA, CESC, LIHC and THYM. Compared with normal tissue, VPS13A methylation levels were higher in some primary tumors. KEGG gene enrichment indicates that VPS13A is involved in RNA degradation, autophagy, cell senescence, cell cycle, apoptosis and other pathways. Conclusion VPS13A is closely related to the occurrence and progression of tumors and can be used as a biomarker for tumor screening and diagnosis. The level of VPS13A expression and the presence of mutations affect the prognosis of patients with certain cancers, which can be determined by early genetic testing.
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Affiliation(s)
- Xue Qin Zhang
- Department of Gynecology and Oncology, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, People's Republic of China.,Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, People's Republic of China
| | - Li Li
- Department of Gynecology and Oncology, Guangxi Medical University Cancer Hospital, Nanning, Guangxi, People's Republic of China.,Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor, Ministry of Education, Nanning, Guangxi, People's Republic of China
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6
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Abbas MM, Thenral SG, Ramprasad VL, Walker RH, Kukkle PL. Chorea-acanthocytosis: 3 New Families with Novel Genetic and Metabolic Findings. Ann Indian Acad Neurol 2021; 24:452-456. [PMID: 34447025 PMCID: PMC8370142 DOI: 10.4103/aian.aian_215_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/27/2020] [Accepted: 09/23/2020] [Indexed: 11/05/2022] Open
Affiliation(s)
| | - S G Thenral
- Medgenome Labs Pvt Ltd, Bangalore, Karnataka, India
| | | | - Ruth H Walker
- Department of Neurology, James J. Peters Veterans Affairs Medical Center, Bronx, New York, USA.,Department of Neurology, Mount Sinai School of Medicine, New York, USA
| | - Prashanth Lingappa Kukkle
- Parkinson and Ageing Research Foundation, Bangalore, Karnataka, India.,Center for Parkinson's Disease and Movement Disorders Clinic, Vikram Hospitals, Bangalore, Karnataka, India.,Parkinson's Disease and Movement Disorders Clinic, Bangalore, Karnataka, India
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7
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Targeting Lyn Kinase in Chorea-Acanthocytosis: A Translational Treatment Approach in a Rare Disease. J Pers Med 2021; 11:jpm11050392. [PMID: 34068769 PMCID: PMC8150322 DOI: 10.3390/jpm11050392] [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: 04/14/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022] Open
Abstract
Background: Chorea-acanthocytosis (ChAc) is a neurodegenerative disease caused by mutations in the VPS13A gene. It is characterized by several neurological symptoms and the appearance of acanthocytes. Elevated tyrosine kinase Lyn activity has been recently identified as one of the key pathophysiological mechanisms in this disease, and therefore represents a promising drug target. Methods: We evaluated an individual off-label treatment with the tyrosine kinase inhibitor dasatinib (100 mg/d, 25.8–50.4 weeks) of three ChAc patients. Alongside thorough safety monitoring, we assessed motor and non-motor scales (e.g., MDS-UPDRS, UHDRS, quality of life) as well as routine and experimental laboratory parameters (e.g., serum neurofilament, Lyn kinase activity, actin cytoskeleton in red blood cells). Results: Dasatinib appeared to be reasonably safe. The clinical parameters remained stable without significant improvement or deterioration. Regain of deep tendon reflexes was observed in one patient. Creatine kinase, serum neurofilament levels, and acanthocyte count did not reveal consistent effects. However, a reduction of initially elevated Lyn kinase activity and accumulated autophagy markers, as well as a partial restoration of the actin cytoskeleton, was found in red blood cells. Conclusions: We report on the first treatment approach with disease-modifying intention in ChAc. The experimental parameters indicate target engagement in red blood cells, while clinical effects on the central nervous system could not be proven within a rather short treatment time. Limited knowledge on the natural history of ChAc and the lack of appropriate biomarkers remain major barriers for “clinical trial readiness”. We suggest a panel of outcome parameters for future clinical trials in ChAc.
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8
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Hosseinzadeh Z, Hauser S, Singh Y, Pelzl L, Schuster S, Sharma Y, Höflinger P, Zacharopoulou N, Stournaras C, Rathbun DL, Zrenner E, Schöls L, Lang F. Decreased Na +/K + ATPase Expression and Depolarized Cell Membrane in Neurons Differentiated from Chorea-Acanthocytosis Patients. Sci Rep 2020; 10:8391. [PMID: 32439941 PMCID: PMC7242441 DOI: 10.1038/s41598-020-64845-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 04/17/2020] [Indexed: 02/03/2023] Open
Abstract
Loss of function mutations of the chorein-encoding gene VPS13A lead to chorea-acanthocytosis (ChAc), a neurodegenerative disorder with accelerated suicidal neuronal cell death, which could be reversed by lithium. Chorein upregulates the serum and glucocorticoid inducible kinase SGK1. Targets of SGK1 include the Na+/K+-ATPase, a pump required for cell survival. To explore whether chorein-deficiency affects Na+/K+ pump capacity, cortical neurons were differentiated from iPSCs generated from fibroblasts of ChAc patients and healthy volunteers. Na+/K+ pump capacity was estimated from K+-induced whole cell outward current (pump capacity). As a result, the pump capacity was completely abolished in the presence of Na+/K+ pump-inhibitor ouabain (100 µM), was significantly smaller in ChAc neurons than in control neurons, and was significantly increased in ChAc neurons by lithium treatment (24 hours 2 mM). The effect of lithium was reversed by SGK1-inhibitor GSK650394 (24 h 10 µM). Transmembrane potential (Vm) was significantly less negative in ChAc neurons than in control neurons, and was significantly increased in ChAc neurons by lithium treatment (2 mM, 24 hours). The effect of lithium on Vm was virtually abrogated by ouabain. Na+/K+ α1-subunit transcript levels and protein abundance were significantly lower in ChAc neurons than in control neurons, an effect reversed by lithium treatment (2 mM, 24 hours). In conclusion, consequences of chorein deficiency in ChAc include impaired Na+/K+ pump capacity.
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Affiliation(s)
- Zohreh Hosseinzadeh
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany.,Department of Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Stefan Hauser
- German Center for Neurodegenerative Diseases, Tübingen, Germany.,Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Yogesh Singh
- Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Lisann Pelzl
- Transfusion Medicine, Medical Faculty, Eberhard Karl University, Tübingen, Germany
| | - Stefanie Schuster
- German Center for Neurodegenerative Diseases, Tübingen, Germany.,Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Yamini Sharma
- Department of Internal Medicine III, University of Tübingen, Tübingen, Germany
| | - Philip Höflinger
- German Center for Neurodegenerative Diseases, Tübingen, Germany.,Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Nefeli Zacharopoulou
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece.,Department of Vegetative and Clinical Physiology, University of Tübingen, Tübingen, Germany
| | - Christos Stournaras
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Daniel L Rathbun
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany.,Department Ophthalmology, Bionics and Vision, Henry Ford Hospital, Henry Ford, United States
| | - Eberhart Zrenner
- Department of Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Ludger Schöls
- German Center for Neurodegenerative Diseases, Tübingen, Germany.,Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Florian Lang
- Department of Vegetative and Clinical Physiology, University of Tübingen, Tübingen, Germany.
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9
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Cheng X, Ferino E, Hull H, Jickling GC, Ander BP, Stamova B, Sharp FR. Smoking affects gene expression in blood of patients with ischemic stroke. Ann Clin Transl Neurol 2019; 6:1748-1756. [PMID: 31436916 PMCID: PMC6764500 DOI: 10.1002/acn3.50876] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/27/2019] [Accepted: 07/27/2019] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Though cigarette smoking (CS) is a well-known risk factor for ischemic stroke (IS), there is no data on how CS affects the blood transcriptome in IS patients. METHODS We recruited IS-current smokers (IS-SM), IS-never smokers (IS-NSM), control-smokers (C-SM), and control-never smokers (C-NSM). mRNA expression was assessed on HTA-2.0 microarrays and unique as well as commonly expressed genes identified for IS-SM versus IS-NSM and C-SM versus C-NSM. RESULTS One hundred and fifty-eight genes were differentially expressed in IS-SM versus IS-NSM; 100 genes were differentially expressed in C-SM versus C-NSM; and 10 genes were common to both IS-SM and C-SM (P < 0.01; |fold change| ≥ 1.2). Functional pathway analysis showed the 158 IS-SM-regulated genes were associated with T-cell receptor, cytokine-cytokine receptor, chemokine, adipocytokine, tight junction, Jak-STAT, ubiquitin-mediated proteolysis, and adherens junction signaling. IS-SM showed more altered genes and functional networks than C-SM. INTERPRETATION We propose some of the 10 genes that are elevated in both IS-SM and C-SM (GRP15, LRRN3, CLDND1, ICOS, GCNT4, VPS13A, DAP3, SNORA54, HIST1H1D, and SCARNA6) might contribute to increased risk of stroke in current smokers, and some genes expressed by blood leukocytes and platelets after stroke in smokers might contribute to worse stroke outcomes that occur in smokers.
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Affiliation(s)
- Xiyuan Cheng
- Department of Neurology, University of California at Davis, Sacramento, California.,Toxicology and Pharmacology Graduate Program, University of California at Davis, Davis, California
| | - Eva Ferino
- Department of Neurology, University of California at Davis, Sacramento, California
| | - Heather Hull
- Department of Neurology, University of California at Davis, Sacramento, California
| | - Glen C Jickling
- Department of Neurology, University of California at Davis, Sacramento, California.,Department of Neurology, University of Alberta, Edmonton, California
| | - Bradley P Ander
- Department of Neurology, University of California at Davis, Sacramento, California
| | - Boryana Stamova
- Department of Neurology, University of California at Davis, Sacramento, California
| | - Frank R Sharp
- Department of Neurology, University of California at Davis, Sacramento, California.,Toxicology and Pharmacology Graduate Program, University of California at Davis, Davis, California
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10
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Weber J, Frings L, Rijntjes M, Urbach H, Fischer J, Weiller C, Meyer PT, Klebe S. Chorea-Acanthocytosis Presenting as Autosomal Recessive Epilepsy in a Family With a Novel VPS13A Mutation. Front Neurol 2019; 9:1168. [PMID: 30687222 PMCID: PMC6334619 DOI: 10.3389/fneur.2018.01168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 12/17/2018] [Indexed: 12/17/2022] Open
Abstract
Chorea-acanthocytosis (ChAc) is a rare, adult-onset disease usually characterized by, hence the name, a movement disorder and acanthocytosis in the blood. It is caused by mutations of the VPS13A gene with an autosomal recessive transmission. We report a consanguineous Turkish family with a different and informative clinical and diagnostic course. Three siblings developed seizures and the index patient had been diagnosed with bilateral temporal lobe epilepsy. A key finding, however, was the basal ganglia involvement in neuroimaging although no movement disorder was present. [18F]FDG-PET showed a prominent decline in striatal glucose metabolism at 31 years of age and [123I]FP-CIT-SPECT revealed a moderate loss of striatal dopamine transporter availability. The family was referred for genetic testing and exome sequencing detected a homozygous novel truncating mutation c.4326 T>A (p.Tyr1442*) in VPS13A in all affected siblings. With this case, we present autosomal recessive epilepsy as the predominant phenotype of ChAc with a new homozygous VPS13A mutation and provide pathological structural and molecular neuroimaging findings.
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Affiliation(s)
- Juliane Weber
- Department of Neurology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Lars Frings
- Department of Nuclear Medicine, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Michel Rijntjes
- Department of Neurology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Horst Urbach
- Department of Neuroradiology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Judith Fischer
- Department of Human Genetics, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Cornelius Weiller
- Department of Neurology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Philipp T Meyer
- Department of Nuclear Medicine, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Stephan Klebe
- Department of Neurology, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany.,Department of Neurology, University Hospital of Essen, Essen, Germany
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11
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Lang F, Pelzl L, Hauser S, Hermann A, Stournaras C, Schöls L. To die or not to die SGK1-sensitive ORAI/STIM in cell survival. Cell Calcium 2018; 74:29-34. [PMID: 29807219 DOI: 10.1016/j.ceca.2018.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 12/31/2022]
Abstract
The pore forming Ca2+ release activated Ca2+ channel (CRAC) isoforms ORAI1-3 and their regulators STIM1,2 accomplish store operated Ca2+ entry (SOCE). Activation of SOCE may lead to cytosolic Ca2+ oscillations, which in turn support cell proliferation and cell survival. ORAI/STIM and thus SOCE are upregulated by the serum and glucocorticoid inducible kinase SGK1, a kinase under powerful genomic regulation and activated by phosphorylation via the phosphoinositol-3-phosphate pathway. SGK1 enhances ORAI1 abundance partially by phosphorylation of Nedd4-2, an ubiquitin ligase priming the channel protein for degradation. The SGK1-phosphorylated Nedd4-2 binds to the protein 14-3-3 and is thus unable to ubiquinate ORAI1. SGK1 further increases the ORAI1 and STIM1 protein abundance by activating nuclear factor kappa B (NF-κB), a transcription factor upregulating the expression of STIM1 and ORAI1. SGK1-sensitive upregulation of ORAI/STIM and thus SOCE is triggered by a wide variety of hormones and growth factors, as well as several cell stressors including ischemia, radiation, and cell shrinkage. SGK1 dependent upregulation of ORAI/STIM confers survival of tumor cells and thus impacts on growth and therapy resistance of cancer. On the other hand, SGK1-dependent upregulation of ORAI1 and STIM1 may support survival of neurons and impairment of SGK1-dependent ORAI/STIM activity may foster neurodegeneration. Clearly, further experimental effort is needed to define the mechanisms linking SGK1-dependent upregulation of ORAI1 and STIM1 to cell survival and to define the impact of SGK1-dependent upregulation of ORAI1 and STIM1 on malignancy and neurodegenerative disease.
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Affiliation(s)
- Florian Lang
- Department of Vegetative Physiology, Eberhad Karls University, Wilhelmstr. 56, D-72074 Tübingen, Germany.
| | - Lisann Pelzl
- Department of Vegetative Physiology, Eberhad Karls University, Wilhelmstr. 56, D-72074 Tübingen, Germany
| | - Stefan Hauser
- German Center for Neurodegenerative Diseases, Research Site Tübingen, Germany; Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Andreas Hermann
- Department of Neurology and Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Germany & DZNE, German Center for Neurodegenerative Diseases, Research Site Dresden, Germany
| | - Christos Stournaras
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Ludger Schöls
- German Center for Neurodegenerative Diseases, Research Site Tübingen, Germany; Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
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