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Dong W, Li Q, Lu X, Lan J, Qiu Z, Wang X, Wang J, Zheng X, Chen S, Zhang C, Jin J. Ceramide kinase-mediated C1P metabolism attenuates acute liver injury by inhibiting the interaction between KEAP1 and NRF2. Exp Mol Med 2024; 56:946-958. [PMID: 38556546 PMCID: PMC11059394 DOI: 10.1038/s12276-024-01203-4] [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: 10/05/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 04/02/2024] Open
Abstract
Acute liver injury is the basis of the pathogenesis of diverse liver diseases. However, the mechanism underlying liver injury is complex and not completely understood. In our study, we revealed that CERK, which phosphorylates ceramide to produce ceramide-1-phosphate (C1P), was the sphingolipid pathway-related protein that had the most significantly upregulated expression during acute liver injury. A functional study confirmed that CERK and C1P attenuate hepatic injury both in vitro and in vivo through antioxidant effects. Mechanistic studies have shown that CERK and C1P positively regulate the protein expression of NRF2, which is a crucial protein that helps maintain redox homeostasis. Furthermore, our results indicated that C1P disrupted the interaction between NRF2 and KEAP1 by competitively binding to KEAP1, which allowed for the nuclear translocation of NRF2. In addition, pull-down assays and molecular docking analyses revealed that C1P binds to the DGR domain of KEAP1, which allows it to maintain its interaction with NRF2. Importantly, these findings were verified in human primary hepatocytes and a mouse model of hepatic ischemia‒reperfusion injury. Taken together, our findings demonstrated that CERK-mediated C1P metabolism attenuates acute liver injury via the binding of C1P to the DGR domain of KEAP1 and subsequently the release and nuclear translocation of NRF2, which activates the transcription of cytoprotective and antioxidant genes. Our study suggested that the upregulation of CERK and C1P expression may serve as a potential antioxidant strategy to alleviate acute liver injury.
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Affiliation(s)
- Wei Dong
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Department of Hepatobiliary and Pancreatic Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
- Xiangya Hospital, Central South University, Changsha, Hunan, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
| | - Qing Li
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China
| | - Xing Lu
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China
| | - Jianfeng Lan
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China
| | - Zhidong Qiu
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Xiangya Hospital, Central South University, Changsha, Hunan, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China
| | - Xuehong Wang
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Xiangya Hospital, Central South University, Changsha, Hunan, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China
| | - Junnan Wang
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China
| | - Xiaojiao Zheng
- Center for Translational Medicine and Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sifan Chen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-Sen Memorial Hospital, Foshan, Guangdong, China
| | - Chong Zhang
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China.
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China.
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China.
| | - Junfei Jin
- Guangxi Key Laboratory of Molecular Medicine in Liver Injury and Repair, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China.
- Xiangya Hospital, Central South University, Changsha, Hunan, China.
- Guangxi Health Commission Key Laboratory of Basic Research in Sphingolipid Metabolism Related Diseases, the Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, China.
- China-USA Lipids in Health and Disease Research Center, Guilin Medical University, Guilin, Guangxi, China.
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Fu S, Fu J, Mobasher-Jannat A, Jadidi K, Li Y, Chen R, Imani S, Cheng J. Novel pathogenic CERKL variant in Iranian familial with inherited retinal dystrophies: genotype-phenotype correlation. 3 Biotech 2023; 13:166. [PMID: 37162806 PMCID: PMC10163994 DOI: 10.1007/s13205-023-03535-w] [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: 11/09/2022] [Accepted: 03/28/2023] [Indexed: 05/11/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) include a large chronic heterogeneity genetic disease. While many disease-causing pathogenic variants were involved in the progression of IRD, the Ceramide Kinase Like (CERKL) gene variant in Iranian patients is not well characterized. In this study, a consanguineous Iranian family with three generations was recruited whom presented with the clinical diagnosis of autosomal recessive IRD. By targeted next-generation sequencing (TGS) and Sanger sequencing, the proband was found to have a novel, pathological homozygous deletion variant c.560_568del (p.187_190del) of the CERKL gene (NM_001030311.2) that co-segregated with the disease in all affected family members. The Cerkl is highly expressed in the later four developmental retinal stages, playing a vital role in retina degeneration. Therefore, the identification of a novel, homozygous deletion CERKL variant c.560_568del (p.187_190del) in an IRD familial cohort descent provides insights into the molecular pathogenesis of IRD and facilitates genetic counseling and disease prediction.
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Affiliation(s)
- Shangyi Fu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA
- School of Medicine, Baylor College of Medicine, Houston, TX USA
| | - Jiewen Fu
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000 People’s Republic of China
| | | | - Khosrow Jadidi
- Department of Ophthalmology, Bina Eye Hospital Research Center, Tehran, Iran
| | - Yumei Li
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX USA
| | - Saber Imani
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000 People’s Republic of China
- Shulan International Medical College, Zhejiang Shuren University, Hangzhou, Zhejiang China
| | - Jingliang Cheng
- Key Laboratory of Epigenetics and Oncology, Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000 People’s Republic of China
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Huang S, Hong Z, Zhang L, Guo J, Li Y, Li K. CERKL alleviates ischemia reperfusion-induced nervous system injury through modulating the SIRT1/PINK1/Parkin pathway and mitophagy induction. Biol Chem 2022; 403:691-701. [PMID: 35238502 DOI: 10.1515/hsz-2021-0411] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/16/2022] [Indexed: 12/26/2022]
Abstract
Recent studies showed that Ceramide Kinase-Like Protein (CERKL)was expressed in the nerve cells and could regulate autophagy. Sirtuin-1 (SIRT1) is the regulator of the mitophagy, which can be stabilized by CERKL. Furthermore, the study also revealed that the SIRT1 induced mitophagy by activating PINK1/Parkin signaling. Therefore, we speculated that CERKL has potential to activate the SIRT1/PINK1/Parkin pathway to induce mitophagy. In this study, cerebral ischemia reperfusion mouse model was established. CERKL was overexpressed in those mice and human neuroblastoma cells. Tunel staining and flow cytometry were applied for the detection of cell apoptosis. The ratios of LC3Ⅱ to LC3Ⅰ and the expression of LC3Ⅱ in mitochondria were determined by gel electrophoresis. Overexpression of CERKL alleviated the cerebral ischemia reperfusion injury and damage to OGD/R human neuroblastoma cells. Overexpression of CERKL enhanced the expression of LC3 Ⅱ in mitochondria and induced occurrence of mitophagy. Overexpression of CERKL promoted the stability of SIRT1 and facilitated the expression of PINK1 and Parkin in those cells. Knockdown of PINK1 impeded the mitophagy and suppressed the expression of LC3 Ⅱ in mitochondria. It can be concluded that CERKL alleviated the ischemia reperfusion induced nervous system injury through inducing mitophagy in a SIRT1/PINK1/Parkin dependent pathway.
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Affiliation(s)
- Shaoyue Huang
- Department of Neurology Cangzhou Central Hospital, No. 16 Xinhua Western Road, Cangzhou 061000, Hebei, China
| | - Zhen Hong
- Department of Neurology Cangzhou Central Hospital, No. 16 Xinhua Western Road, Cangzhou 061000, Hebei, China
| | - Leguo Zhang
- Department of Neurology Cangzhou Central Hospital, No. 16 Xinhua Western Road, Cangzhou 061000, Hebei, China
| | - Jian Guo
- Department of Neurology Cangzhou Central Hospital, No. 16 Xinhua Western Road, Cangzhou 061000, Hebei, China
| | - Yanhua Li
- Department of Neurology Cangzhou Central Hospital, No. 16 Xinhua Western Road, Cangzhou 061000, Hebei, China
| | - Kuo Li
- Department of Neurology Cangzhou Central Hospital, No. 16 Xinhua Western Road, Cangzhou 061000, Hebei, China
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Mirra S, García-Arroyo R, B Domènech E, Gavaldà-Navarro A, Herrera-Úbeda C, Oliva C, Garcia-Fernàndez J, Artuch R, Villarroya F, Marfany G. CERKL, a retinal dystrophy gene, regulates mitochondrial function and dynamics in the mammalian retina. Neurobiol Dis 2021; 156:105405. [PMID: 34048907 DOI: 10.1016/j.nbd.2021.105405] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/06/2021] [Accepted: 05/21/2021] [Indexed: 11/30/2022] Open
Abstract
The retina is a highly active metabolic organ that displays a particular vulnerability to genetic and environmental factors causing stress and homeostatic imbalance. Mitochondria constitute a bioenergetic hub that coordinates stress response and cellular homeostasis, therefore structural and functional regulation of the mitochondrial dynamic network is essential for the mammalian retina. CERKL (ceramide kinase like) is a retinal degeneration gene whose mutations cause Retinitis Pigmentosa in humans, a visual disorder characterized by photoreceptors neurodegeneration and progressive vision loss. CERKL produces multiple isoforms with a dynamic subcellular localization. Here we show that a pool of CERKL isoforms localizes at mitochondria in mouse retinal ganglion cells. The depletion of CERKL levels in CerklKD/KO(knockdown/knockout) mouse retinas cause increase of autophagy, mitochondrial fragmentation, alteration of mitochondrial distribution, and dysfunction of mitochondrial-dependent bioenergetics and metabolism. Our results support CERKL as a regulator of autophagy and mitochondrial biology in the mammalian retina.
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Affiliation(s)
- Serena Mirra
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain.
| | - Rocío García-Arroyo
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Elena B Domènech
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Aleix Gavaldà-Navarro
- Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Barcelona, Spain; CIBEROBN, Instituto de Salud Carlos III, Spain
| | - Carlos Herrera-Úbeda
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Clara Oliva
- Clinical Biochemistry Department, Hospital Sant Joan de Déu, Spain
| | - Jordi Garcia-Fernàndez
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain; Clinical Biochemistry Department, Hospital Sant Joan de Déu, Spain
| | - Francesc Villarroya
- Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain; Department of Biochemistry and Molecular Biomedicine, Barcelona, Spain; CIBEROBN, Instituto de Salud Carlos III, Spain
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics and Institute of Biomedicine (IBUB), Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain; Institut de Biomedicina de la Universitat de Barcelona- Institut de Recerca Hospital Sant Joan de Déu, IBUB-IRSJD, Barcelona, Spain.
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5
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Unique Variant Spectrum in a Jordanian Cohort with Inherited Retinal Dystrophies. Genes (Basel) 2021; 12:genes12040593. [PMID: 33921607 PMCID: PMC8074154 DOI: 10.3390/genes12040593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/07/2021] [Accepted: 04/14/2021] [Indexed: 12/12/2022] Open
Abstract
Whole Exome Sequencing (WES) is a powerful approach for detecting sequence variations in the human genome. The aim of this study was to investigate the genetic defects in Jordanian patients with inherited retinal dystrophies (IRDs) using WES. WES was performed on proband patients' DNA samples from 55 Jordanian families. Sanger sequencing was used for validation and segregation analysis of the detected, potential disease-causing variants (DCVs). Thirty-five putatively causative variants (6 novel and 29 known) in 21 IRD-associated genes were identified in 71% of probands (39 of the 55 families). Three families showed phenotypes different from the typically reported clinical findings associated with the causative genes. To our knowledge, this is the largest genetic analysis of IRDs in the Jordanian population to date. Our study also confirms that WES is a powerful tool for the molecular diagnosis of IRDs in large patient cohorts.
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O'Shaughnessy RFL. Ceramide kinase-like protein, 'the kinase that isn't', finds a role in skin cancer stress relief. Br J Dermatol 2021; 185:14-15. [PMID: 33755200 DOI: 10.1111/bjd.19888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 01/29/2021] [Indexed: 11/30/2022]
Affiliation(s)
- R F L O'Shaughnessy
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Queen Mary University of London, London, UK
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Simon MV, Basu SK, Qaladize B, Grambergs R, Rotstein NP, Mandal N. Sphingolipids as critical players in retinal physiology and pathology. J Lipid Res 2021; 62:100037. [PMID: 32948663 PMCID: PMC7933806 DOI: 10.1194/jlr.tr120000972] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/04/2020] [Indexed: 12/24/2022] Open
Abstract
Sphingolipids have emerged as bioactive lipids involved in the regulation of many physiological and pathological processes. In the retina, they have been established to participate in numerous processes, such as neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Dysregulation of sphingolipids is therefore crucial in the onset and progression of retinal diseases. This review examines the involvement of sphingolipids in retinal physiology and diseases. Ceramide (Cer) has emerged as a common mediator of inflammation and death of neuronal and retinal pigment epithelium cells in animal models of retinopathies such as glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa. Sphingosine-1-phosphate (S1P) has opposite roles, preventing photoreceptor and ganglion cell degeneration but also promoting inflammation, fibrosis, and neovascularization in AMD, glaucoma, and pro-fibrotic disorders. Alterations in Cer, S1P, and ceramide 1-phosphate may also contribute to uveitis. Notably, use of inhibitors that either prevent Cer increase or modulate S1P signaling, such as Myriocin, desipramine, and Fingolimod (FTY720), preserves neuronal viability and retinal function. These findings underscore the relevance of alterations in the sphingolipid metabolic network in the etiology of multiple retinopathies and highlight the potential of modulating their metabolism for the design of novel therapeutic approaches.
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Affiliation(s)
- M Victoria Simon
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Sandip K Basu
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Bano Qaladize
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Richard Grambergs
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina.
| | - Nawajes Mandal
- Departments of Ophthalmology and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
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Meyer JM, Lee E, Celli A, Park K, Cho R, Lambert W, Pitchford M, Gordon M, Tsai K, Cleaver J, Arron ST, Mauro TM. CERKL is upregulated in cutaneous squamous cell carcinoma and maintains cellular sphingolipids and resistance to oxidative stress. Br J Dermatol 2021; 185:147-152. [PMID: 33393080 DOI: 10.1111/bjd.19753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND Ceramide kinase-like protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism. OBJECTIVES To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress. METHODS CERKL expression was determined by RNA-Seq, quantitative polymerase chain reaction and immunohistochemistry. CERKL was knocked down in cSCC cells using small interfering RNA. Sphingolipid content was analysed by liquid chromatography-mass spectrometry. Oxidative stress was induced by treatment with H2 O2 , and apoptosis was measured using flow cytometry to determine annexin V binding. RESULTS CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL is also expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress. CONCLUSIONS These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.
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Affiliation(s)
- J M Meyer
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - E Lee
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - A Celli
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - K Park
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - R Cho
- Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - W Lambert
- Pathology and Laboratory Medicine, Rutgers University, Newark, NJ, USA
| | - M Pitchford
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - M Gordon
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - K Tsai
- Moffitt Cancer Center, Tampa, FL, USA
| | - J Cleaver
- Department of Dermatology, UC San Francisco, San Francisco, CA, USA.,Department of Pharmaceutical Chemistry, UC San Francisco, San Francisco, CA, USA
| | - S T Arron
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
| | - T M Mauro
- Dermatology Service, VA Medical Center and Department of Dermatology, UC San Francisco, San Francisco, CA, USA
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Genetic and Clinical Findings in an Ethnically Diverse Cohort with Retinitis Pigmentosa Associated with Pathogenic Variants in CERKL. Genes (Basel) 2020; 11:genes11121497. [PMID: 33322828 PMCID: PMC7763961 DOI: 10.3390/genes11121497] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 01/06/2023] Open
Abstract
Autosomal recessive retinitis pigmentosa is caused by mutations in over 40 genes, one of which is the ceramide kinase-like gene (CERKL). We present a case series of six patients from six unrelated families diagnosed with inherited retinal dystrophies (IRD) and with two variants in CERKL recruited from a multi-ethnic British population. A retrospective review of clinical data in these patients was performed and included colour fundus photography, fundus autofluorescence (AF) imaging, spectral domain–optical coherence tomography (SD–OCT), visual fields and electroretinogram (ERG) assessment where available. Three female and three male patients were included. Age at onset ranged from 7 years old to 45 years, with three presenting in their 20s and two presenting in their 40s. All but one had central visual loss as one of their main presenting symptoms. Four patients had features of retinitis pigmentosa with significant variation in severity and extent of disease, and two patients had no pigment deposition with only macular involvement clinically. Seven variants in CERKL were identified, of which three are novel. The inherited retinopathies associated with the CERKL gene vary in age at presentation and in degree of severity, but generally are characterised by a central visual impairment early on.
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10
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Meyer JM, Lee E, Celli A, Park K, Cho R, Lambert W, Pitchford M, Gordon M, Tsai K, Cleaver J, Arron ST, Mauro TM. CERKL is Upregulated in Cutaneous Squamous Cell Carcinoma and Maintains Cellular Sphingolipids and Resistance to Oxidative Stress. Br J Dermatol 2020:10.1111/bjd.19707. [PMID: 33270220 PMCID: PMC8172666 DOI: 10.1111/bjd.19707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Ceramide Kinase-Like Protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease, retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism. OBJECTIVES To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress. METHODS CERKL expression was determined by RNA-Seq, qPCR and immunohistochemistry. CERKL was knocked down in cSCC cells using siRNA. Sphingolipid content was analyzed by liquid chromatography-mass spectrometry (LC-MS). Oxidative stress was induced by treatment with H2 O2 , and apoptosis was measured using flow cytometry to determine annexin v binding. RESULTS CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL also is expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress. CONCLUSIONS These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.
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Affiliation(s)
- J M Meyer
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - E Lee
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - A Celli
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - K Park
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - R Cho
- Department of Dermatology, UC San Francisco, CA, USA
| | - W Lambert
- Pathology and Laboratory Medicine, Rutgers University, Newark, NJ, USA
| | - M Pitchford
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - M Gordon
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - K Tsai
- Moffitt Cancer Center, Tampa, FL, USA
| | - J Cleaver
- Departments of Dermatology and Pharmaceutical Chemistry, UC San Francisco, CA, USA
| | - S T Arron
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
| | - T M Mauro
- Dermatology Service, VA Medical Center, Department of Dermatology, UC San Francisco, CA, USA
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Domènech EB, Andrés R, López-Iniesta MJ, Mirra S, García-Arroyo R, Milla S, Sava F, Andilla J, Loza-Álvarez P, de la Villa P, Gonzàlez-Duarte R, Marfany G. A New Cerkl Mouse Model Generated by CRISPR-Cas9 Shows Progressive Retinal Degeneration and Altered Morphological and Electrophysiological Phenotype. Invest Ophthalmol Vis Sci 2020; 61:14. [PMID: 32658961 PMCID: PMC7425692 DOI: 10.1167/iovs.61.8.14] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/14/2020] [Indexed: 12/14/2022] Open
Abstract
Purpose Close to 100 genes cause retinitis pigmentosa, a Mendelian rare disease that affects 1 out of 4000 people worldwide. Mutations in the ceramide kinase-like gene (CERKL) are a prevalent cause of autosomal recessive cause retinitis pigmentosa and cone-rod dystrophy, but the functional role of this gene in the retina has yet to be fully determined. We aimed to generate a mouse model that resembles the phenotypic traits of patients carrying CERKL mutations to undertake functional studies and assay therapeutic approaches. Methods The Cerkl locus has been deleted (around 97 kb of genomic DNA) by gene editing using the CRISPR-Cas9 D10A nickase. Because the deletion of the Cerkl locus is lethal in mice in homozygosis, a double heterozygote mouse model with less than 10% residual Cerkl expression has been generated. The phenotypic alterations of the retina of this new model have been characterized at the morphological and electrophysiological levels. Results This CerklKD/KO model shows retinal degeneration, with a decreased number of cones and progressive photoreceptor loss, poorly stacked photoreceptor outer segment membranes, defective retinal pigment epithelium phagocytosis, and altered electrophysiological recordings in aged retinas. Conclusions To our knowledge, this is the first Cerkl mouse model to mimic many of the phenotypic traits, including the slow but progressive retinal degeneration, shown by human patients carrying CERKL mutations. This useful model will provide unprecedented insights into the retinal molecular pathways altered in these patients and will contribute to the design of effective treatments.
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Affiliation(s)
- Elena B. Domènech
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- CIBERER/ISCIII, University of Barcelona, Barcelona, Spain
| | - Rosa Andrés
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- CIBERER/ISCIII, University of Barcelona, Barcelona, Spain
| | - M. José López-Iniesta
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Serena Mirra
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- CIBERER/ISCIII, University of Barcelona, Barcelona, Spain
| | - Rocío García-Arroyo
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Santiago Milla
- Department of Systems Biology, University of Alcalá, Madrid, Spain
| | - Florentina Sava
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Jordi Andilla
- ICFO–The Institute of Photonic Sciences, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Pablo Loza-Álvarez
- ICFO–The Institute of Photonic Sciences, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Pedro de la Villa
- Department of Systems Biology, University of Alcalá, Madrid, Spain
- Ramón y Cajal Institute for Health Research, Madrid, Spain
| | - Roser Gonzàlez-Duarte
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- CIBERER/ISCIII, University of Barcelona, Barcelona, Spain
- DBGen Ocular Genomics, Barcelona, Spain
| | - Gemma Marfany
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- CIBERER/ISCIII, University of Barcelona, Barcelona, Spain
- DBGen Ocular Genomics, Barcelona, Spain
- Institute of Biomedicine, University of Barcelona, Barcelona, Spain
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12
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Simón MV, Prado Spalm FH, Vera MS, Rotstein NP. Sphingolipids as Emerging Mediators in Retina Degeneration. Front Cell Neurosci 2019; 13:246. [PMID: 31244608 PMCID: PMC6581011 DOI: 10.3389/fncel.2019.00246] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/17/2019] [Indexed: 12/12/2022] Open
Abstract
The sphingolipids ceramide (Cer), sphingosine-1-phosphate (S1P), sphingosine (Sph), and ceramide-1-phosphate (C1P) are key signaling molecules that regulate major cellular functions. Their roles in the retina have gained increasing attention during the last decade since they emerge as mediators of proliferation, survival, migration, neovascularization, inflammation and death in retina cells. As exacerbation of these processes is central to retina degenerative diseases, they appear as crucial players in their progression. This review analyzes the functions of these sphingolipids in retina cell types and their possible pathological roles. Cer appears as a key arbitrator in diverse retinal pathologies; it promotes inflammation in endothelial and retina pigment epithelium (RPE) cells and its increase is a common feature in photoreceptor death in vitro and in animal models of retina degeneration; noteworthy, inhibiting Cer synthesis preserves photoreceptor viability and functionality. In turn, S1P acts as a double edge sword in the retina. It is essential for retina development, promoting the survival of photoreceptors and ganglion cells and regulating proliferation and differentiation of photoreceptor progenitors. However, S1P has also deleterious effects, stimulating migration of Müller glial cells, angiogenesis and fibrosis, contributing to the inflammatory scenario of proliferative retinopathies and age related macular degeneration (AMD). C1P, as S1P, promotes photoreceptor survival and differentiation. Collectively, the expanding role for these sphingolipids in the regulation of critical processes in retina cell types and in their dysregulation in retina degenerations makes them attractive targets for treating these diseases.
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Affiliation(s)
- M Victoria Simón
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Facundo H Prado Spalm
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Marcela S Vera
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
| | - Nora P Rotstein
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Departamento De Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Argentine National Research Council (CONICET), Bahía Blanca, Argentina
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13
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Hu X, Lu Z, Yu S, Reilly J, Liu F, Jia D, Qin Y, Han S, Liu X, Qu Z, Lv Y, Li J, Huang Y, Jiang T, Jia H, Wang Q, Liu J, Shu X, Tang Z, Liu M. CERKL regulates autophagy via the NAD-dependent deacetylase SIRT1. Autophagy 2019; 15:453-465. [PMID: 30205735 PMCID: PMC6351130 DOI: 10.1080/15548627.2018.1520548] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 08/18/2018] [Accepted: 08/22/2018] [Indexed: 01/07/2023] Open
Abstract
Macroautophagy/autophagy is an important intracellular mechanism for the maintenance of cellular homeostasis. Here we show that the CERKL (ceramide kinase like) gene, a retinal degeneration (RD) pathogenic gene, plays a critical role in regulating autophagy by stabilizing SIRT1. In vitro and in vivo, suppressing CERKL results in impaired autophagy. SIRT1 is one of the main regulators of acetylation/deacetylation in autophagy. In CERKL-depleted retinas and cells, SIRT1 is downregulated. ATG5 and ATG7, 2 essential components of autophagy, show a higher degree of acetylation in CERKL-depleted cells. Overexpression of SIRT1 rescues autophagy in CERKL-depleted cells, whereas CERKL loses its function of regulating autophagy in SIRT1-depleted cells, and overexpression of CERKL upregulates SIRT1. Finally, we show that CERKL directly interacts with SIRT1, and may regulate its phosphorylation at Ser27 to stabilize SIRT1. These results show that CERKL is an important regulator of autophagy and it plays this role by stabilizing the deacetylase SIRT1.
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Affiliation(s)
- Xuebin Hu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Zhaojing Lu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Shanshan Yu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - James Reilly
- Department of Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Fei Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Danna Jia
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Yayun Qin
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Shanshan Han
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
- Department of Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Xiliang Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Zhen Qu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Yuexia Lv
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Jingzhen Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Tao Jiang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Haibo Jia
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Qing Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Jingyu Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow, UK
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
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14
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Azab B, Barham R, Ali D, Dardas Z, Rashdan L, Bijawi M, Maswadi R, Awidi A, Jafar H, Abu-Ameerh M, Al-Bdour M, Amr S, Awidi A. Novel CERKL variant in consanguineous Jordanian pedigrees with inherited retinal dystrophies. Can J Ophthalmol 2019; 54:51-59. [DOI: 10.1016/j.jcjo.2018.02.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/24/2018] [Accepted: 02/27/2018] [Indexed: 01/02/2023]
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15
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Sengillo JD, Cho GY, Paavo M, Lee W, White E, Jauregui R, Sparrow JR, Allikmets R, Tsang SH. Hyperautofluorescent Dots are Characteristic in Ceramide Kinase Like-associated Retinal Degeneration. Sci Rep 2019; 9:876. [PMID: 30696906 PMCID: PMC6351646 DOI: 10.1038/s41598-018-37578-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/27/2018] [Indexed: 11/17/2022] Open
Abstract
There is a lack of studies which seek to discern disease expression in patients with mutations that alter retinal ceramide metabolism, specifically in the ceramide kinase like (CERKL) gene. This cross-sectional case series reports a novel phenotypic manifestation of CERKL-associated retinopathy. Four unrelated patients with homozygous CERKL mutations underwent a complete ocular exam, spectral-domain optical coherence tomography, short-wavelength fundus autofluorescence (SW-AF), quantitative autofluorescence (qAF), and full-field electroretinogram (ffERG). Decreased visual acuity and early-onset maculopathy were present in all patients. All four patients had extensive hyperautofluorescent foci surrounding an area of central atrophy on SW-AF imaging, which has not been previously characterized. An abnormal spatial distribution of qAF signal was seen in one patient, and abnormally elevated qAF8 signal in another patient. FfERG recordings showed markedly attenuated rod and cone response in all patients. We conclude that these patients exhibit several features that, collectively, may warrant screening of CERKL as a first candidate: early-onset maculopathy, severe generalized retinal dysfunction, peripheral lacunae, intraretinal pigment migration, and hyperautofluorescent foci on SW-AF.
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Affiliation(s)
- Jesse D Sengillo
- Department of Internal Medicine, Reading Hospital, West Reading, PA, USA
| | - Galaxy Y Cho
- Frank H. Netter MD School of Medicine, Quinnipiac University, North Haven, CT, USA
| | - Maarjaliis Paavo
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Winston Lee
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Eugenia White
- Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | | | - Janet R Sparrow
- Department of Ophthalmology, Columbia University, New York, NY, USA.,Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY, USA.,Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, New York, USA. .,Department of Ophthalmology, Columbia University, New York, NY, USA. .,Department of Pathology & Cell Biology, Columbia University, New York, NY, USA. .,Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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16
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Yu J, Kim HM, Kim KP, Son Y, Kim MS, Park KS. Ceramide kinase regulates the migration of bone marrow-derived mesenchymal stem cells. Biochem Biophys Res Commun 2018; 508:361-367. [PMID: 30502084 DOI: 10.1016/j.bbrc.2018.11.154] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 11/22/2018] [Indexed: 11/18/2022]
Abstract
Endogenous bone marrow-derived mesenchymal stem cells (BM-MSCs) are mobilized into peripheral blood and injured tissues by various growth factors and cytokines that are expressed in the injured tissues, such as substance P (SP), stromal cell derived factor-1 (SDF-1), and transforming growth factor-beta (TGF-β). Extracellular bioactive lipid metabolites such as ceramide-1-phosphate and sphingosine-1-phosphate also modulate BM-MSC migration as SP, SDF-1, and TGF-β. However, the roles of intrinsic lipid kinases of BM-MSCs in the stem cell migration are unclear. Here, we demonstrated that ceramide kinase mediates the chemotactic migration of BM-MSCs in response to SP, SDF-1, or TGF-β. Furthermore, a specific inhibitor of ceramide kinase inhibited TGF-β-induced migration of BM-MSCs and N-cadherin that is necessary for BM-MSCs migration in response to TGF-β. Therefore, these results suggest that the intracellular ceramide kinase is required for the BM-MSCs migration and the roles of the intrinsic ceramide kinase in the migration are associated with N-cadherin regulation.
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Affiliation(s)
- Jinyeong Yu
- Graduate School of Biotechnology, Kyung Hee University, Yongin, 17104, South Korea
| | - Hye Min Kim
- Department of Applied Chemistry, Kyung Hee University, Yongin, 17104, South Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, Kyung Hee University, Yongin, 17104, South Korea
| | - Youngsook Son
- Graduate School of Biotechnology, Kyung Hee University, Yongin, 17104, South Korea
| | - Min-Sik Kim
- Department of Applied Chemistry, Kyung Hee University, Yongin, 17104, South Korea; Department of Biomedical Science and Technology, Graduate School, Kyung Hee University, Seoul, 02447, South Korea; Department of New Biology, DGIST, Daegu, 42988, South Korea.
| | - Ki-Sook Park
- Department of Biomedical Science and Technology, Graduate School, Kyung Hee University, Seoul, 02447, South Korea; East-West Medical Research Institute, Kyung Hee University, Seoul, 02447, South Korea; Kyung Hee University Medical Center, Seoul, 02447, South Korea.
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17
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Takahashi H, Ashikawa H, Nakamura H, Murayama T. Phosphorylation and inhibition of ceramide kinase by protein kinase C-β: Their changes by serine residue mutations. Cell Signal 2018; 54:59-68. [PMID: 30448345 DOI: 10.1016/j.cellsig.2018.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/10/2018] [Accepted: 11/14/2018] [Indexed: 01/07/2023]
Abstract
Ceramide kinase (CerK) phosphorylates ceramide to ceramide-1-phosphate (C1P), and various roles for the CerK/C1P pathway in the regulation of cellular/biological functions have been demonstrated. CerK is constitutively phosphorylated at several serine (Ser, S) residues, however, the roles of Ser residues, including their phosphorylation, in CerK activity, have not yet been elucidated in detail. Therefore, we conducted the present study to investigate this issue. In A549 cells expressing wild-type CerK, a treatment with phorbol 12-myristate 13-acetate (PMA) decreased the formation of C1P in a protein kinase C (PKC)-βI/II-mediated manner. In the Phos-tag SDS-PAGE analysis, CerK existed in its phosphorylated form and was further phosphorylated by the PMA treatment in a PKC-βI/II-mediated manner. We examined the effects of the displacement of Ser residues (72/300/340/403/408/427) in CerK by alanine (Ala, A) on its activity and phosphorylation. Triple mutations (S340/408/427A), but not a single or double mutations (S340/408A), in CerK significantly decreased the formation of C1P. PMA-induced phosphorylation levels in S340/408A- and S340/408/427A-CerK were significantly and maximally reduced, respectively, but were similar in CerK with a single mutation and wild-type CerK. Ser residue mutations tested, including six mutations, did not affect PMA-induced decreases in C1P formation more than expected. Treatments with the protein phosphatase inhibitors, okadaic acid and cyclosporine A, decreased the formation of C1P. These results demonstrated that the activity of CerK was regulated in a phosphorylation-dependent manner in cells.
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Affiliation(s)
- Hiromasa Takahashi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
| | - Hitomi Ashikawa
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
| | - Hiroyuki Nakamura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan.
| | - Toshihiko Murayama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675, Japan
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18
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Avela K, Sankila EM, Seitsonen S, Kuuluvainen L, Barton S, Gillies S, Aittomäki K. A founder mutation in CERKL is a major cause of retinal dystrophy in Finland. Acta Ophthalmol 2018; 96:183-191. [PMID: 29068140 DOI: 10.1111/aos.13551] [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: 01/13/2017] [Accepted: 06/28/2017] [Indexed: 11/30/2022]
Abstract
PURPOSE To study the genetic aetiology of retinal dystrophies (RD) in Finnish patients. METHODS A targeted next-generation sequencing (NGS) panel of 105 retinal dystrophy genes was used in a cohort of 55 RD patients. RESULTS The overall diagnostic yield was 60% demonstrating the power of this approach. Interestingly, a missense mutation c.375C>G p.(Cys125Trp) in the CERKL gene was found in 18% of the patients in either a homozygous or compound heterozygous state. Data from Exome Aggregation Consortium (ExAC) Browser show that the CERKL c.375C>G p.(Cys125Trp) allele is enriched in the Finnish population and thus is a founder mutation. Furthermore, we report the clinical picture of 18 patients with mutations in the CERKL gene. CERKL mutations cause a macular-onset disease, in which symptoms first become apparent at the second decade. We also detected other novel founder mutations in the CERKL, EYS, RP1, ABCA4 and GUCY2D genes. CONCLUSION Our report indicates that the first diagnostic test for Finnish patients with sporadic or autosomal recessive RD should be a targeted test for founder mutations in the CERKL, EYS, RP1, ABCA4 and GUCY2D genes. These results confirm the utility of NGS-based gene panels as a powerful method for mutation identification in RD, thus enabling improved genetic counselling for these families.
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Affiliation(s)
- Kristiina Avela
- Department of Clinical Genetics; Helsinki University Hospital; Helsinki Finland
| | - Eeva-Marja Sankila
- Department of Ophthalmology; Helsinki University Hospital; Helsinki Finland
| | - Sanna Seitsonen
- Department of Ophthalmology; Helsinki University Hospital; Helsinki Finland
| | - Liina Kuuluvainen
- Department of Clinical Genetics; Helsinki University Hospital; Helsinki Finland
| | - Stephanie Barton
- St Mary's Hospital; Central Manchester University Hospitals and Manchester Centre for Genomic Medicine; Manchester UK
| | - Stuart Gillies
- St Mary's Hospital; Central Manchester University Hospitals and Manchester Centre for Genomic Medicine; Manchester UK
| | - Kristiina Aittomäki
- Department of Clinical Genetics; Helsinki University Hospital; Helsinki Finland
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19
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Yu S, Li C, Biswas L, Hu X, Liu F, Reilly J, Liu X, Liu Y, Huang Y, Lu Z, Han S, Wang L, Yu Liu J, Jiang T, Shu X, Wong F, Tang Z, Liu M. CERKL gene knockout disturbs photoreceptor outer segment phagocytosis and causes rod-cone dystrophy in zebrafish. Hum Mol Genet 2017; 26:2335-2345. [PMID: 28398482 DOI: 10.1093/hmg/ddx137] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 04/04/2017] [Indexed: 11/13/2022] Open
Abstract
In humans, CERKL mutations cause widespread retinal degeneration: early dysfunction and loss of rod and cone photoreceptors in the outer retina and, progressively, death of cells in the inner retina. Despite intensive efforts, the function of CERKL remains obscure and studies in animal models have failed to clarify the disease mechanism of CERKL mutations. To address this gap in knowledge, we have generated a stable CERKL knockout zebrafish model by TALEN technology and a 7bp deletion in CERKL cDNA that caused the premature termination of CERKL. These CERKL-/- animals showed progressive degeneration of photoreceptor outer segments (OSs) and increased apoptosis of retinal cells, including those in the outer and inner retinal layers. Additionally, we confirmed by immunofluorescence and western-blot that rod degeneration in CERKL-/- zebrafish occurred earlier and was more significant than that in cone cells. Accumulation of shed OSs in the interphotoreceptor matrix was observed by transmission election microscopy (TEM). This suggested that CERKL may regulate the phagocytosis of OSs by the retinal pigment epithelium (RPE). We further found that the phagocytosis-associated protein MERTK was significantly reduced in CERKL-/- zebrafish. Additionally, in ARPE-19 cell lines, knockdown of CERKL also decreased the mRNA and protein level of MERTK, as well as the ox-POS phagocytosis. We conclude that CERKL deficiency in zebrafish may cause rod-cone dystrophy, but not cone-rod dystrophy, while interfering with the phagocytosis function of RPE associated with down-regulation of the expression of MERTK.
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Affiliation(s)
- Shanshan Yu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Chang Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Lincoln Biswas
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Xuebin Hu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Fei Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - James Reilly
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Xiliang Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Ying Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Zhaojing Lu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Shanshan Han
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Lei Wang
- Department of Pathology & Lab Medicine, University of Cincinnati Medical Center, Cincinnati, OH 45267, USA
| | - Jing Yu Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Tao Jiang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4?0BA, UK
| | - Fulton Wong
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.R. China
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Li L, Chen Y, Jiao X, Jin C, Jiang D, Tanwar M, Ma Z, Huang L, Ma X, Sun W, Chen J, Ma Y, M'hamdi O, Govindarajan G, Cabrera PE, Li J, Gupta N, Naeem MA, Khan SN, Riazuddin S, Akram J, Ayyagari R, Sieving PA, Riazuddin SA, Hejtmancik JF. Homozygosity Mapping and Genetic Analysis of Autosomal Recessive Retinal Dystrophies in 144 Consanguineous Pakistani Families. Invest Ophthalmol Vis Sci 2017; 58:2218-2238. [PMID: 28418496 PMCID: PMC5397137 DOI: 10.1167/iovs.17-21424] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose The Pakistan Punjab population has been a rich source for identifying genes causing or contributing to autosomal recessive retinal degenerations (arRD). This study was carried out to delineate the genetic architecture of arRD in the Pakistani population. Methods The genetic origin of arRD in a total of 144 families selected only for having consanguineous marriages and multiple members affected with arRD was examined. Of these, causative mutations had been identified in 62 families while only the locus had been identified for an additional 15. The remaining 67 families were subjected to homozygosity exclusion mapping by screening of closely flanking microsatellite markers at 180 known candidate genes/loci followed by sequencing of the candidate gene for pathogenic changes. Results Of these 67 families subjected to homozygosity mapping, 38 showed homozygosity for at least one of the 180 regions, and sequencing of the corresponding genes showed homozygous cosegregating mutations in 27 families. Overall, mutations were detected in approximately 61.8 % (89/144) of arRD families tested, with another 10.4% (15/144) being mapped to a locus but without a gene identified. Conclusions These results suggest the involvement of unmapped novel genes in the remaining 27.8% (40/144) of families. In addition, this study demonstrates that homozygosity mapping remains a powerful tool for identifying the genetic defect underlying genetically heterogeneous arRD disorders in consanguineous marriages for both research and clinical applications.
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Affiliation(s)
- Lin Li
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China 2Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Yabin Chen
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Chongfei Jin
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 3Department of Medicine, Brookdale University Hospital and Medical Center, New York, New York, United States
| | - Dan Jiang
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Mukesh Tanwar
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 4Department of Genetics, Maharshi Dayanand University Rohtak, Haryana, India
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Li Huang
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiaoyin Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 6Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Wenmin Sun
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jianjun Chen
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 7Department of Ophthalmology, Shanghai Tenth People's Hospital, and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Yan Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Oussama M'hamdi
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Gowthaman Govindarajan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Patricia E Cabrera
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Jiali Li
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Nikhil Gupta
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Shaheen N Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan 9Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan 10National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan 10National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California-San Diego, La Jolla, California, United States
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States 14McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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Bao L, Zhang Y, Wang J, Wang H, Dong N, Su X, Xu M, Wang X. Variations of chromosome 2 gene expressions among patients with lung cancer or non-cancer. Cell Biol Toxicol 2016; 32:419-35. [DOI: 10.1007/s10565-016-9343-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/09/2016] [Indexed: 12/15/2022]
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Chen J, Liu F, Li H, Archacki S, Gao M, Liu Y, Liao S, Huang M, Wang J, Yu S, Li C, Tang Z, Liu M. pVHL interacts with Ceramide kinase like (CERKL) protein and ubiquitinates it for oxygen dependent proteasomal degradation. Cell Signal 2015; 27:2314-23. [DOI: 10.1016/j.cellsig.2015.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 08/01/2015] [Accepted: 08/15/2015] [Indexed: 12/30/2022]
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CERKL interacts with mitochondrial TRX2 and protects retinal cells from oxidative stress-induced apoptosis. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1121-9. [DOI: 10.1016/j.bbadis.2014.04.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 04/02/2014] [Accepted: 04/07/2014] [Indexed: 01/24/2023]
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CERKL, a retinal disease gene, encodes an mRNA-binding protein that localizes in compact and untranslated mRNPs associated with microtubules. PLoS One 2014; 9:e87898. [PMID: 24498393 PMCID: PMC3912138 DOI: 10.1371/journal.pone.0087898] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 12/30/2013] [Indexed: 11/25/2022] Open
Abstract
The function of CERKL (CERamide Kinase Like), a causative gene of retinitis pigmentosa and cone-rod dystrophy, still awaits characterization. To approach its cellular role we have investigated the subcellular localization and interaction partners of the full length CERKL isoform, CERKLa of 532 amino acids, in different cell lines, including a photoreceptor-derived cell line. We demonstrate that CERKLa is a main component of compact and untranslated mRNPs and that associates with other RNP complexes such as stress granules, P-bodies and polysomes. CERKLa is a protein that binds through its N-terminus to mRNAs and interacts with other mRNA-binding proteins like eIF3B, PABP, HSP70 and RPS3. Except for eIF3B, these interactions depend on the integrity of mRNAs but not of ribosomes. Interestingly, the C125W CERKLa pathological mutant does not interact with eIF3B and is absent from these complexes. Compact mRNPs containing CERKLa also associate with microtubules and are found in neurites of neural differentiated cells. These localizations had not been reported previously for any member of the retinal disorders gene family and should be considered when investigating the pathogenic mechanisms and therapeutical approaches in these diseases.
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Riera M, Burguera D, Garcia-Fernàndez J, Gonzàlez-Duarte R. CERKL knockdown causes retinal degeneration in zebrafish. PLoS One 2013; 8:e64048. [PMID: 23671706 PMCID: PMC3650063 DOI: 10.1371/journal.pone.0064048] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 04/08/2013] [Indexed: 12/21/2022] Open
Abstract
The human CERKL gene is responsible for common and severe forms of retinal dystrophies. Despite intense in vitro studies at the molecular and cellular level and in vivo analyses of the retina of murine knockout models, CERKL function remains unknown. In this study, we aimed to approach the developmental and functional features of cerkl in Danio rerio within an Evo-Devo framework. We show that gene expression increases from early developmental stages until the formation of the retina in the optic cup. Unlike the high mRNA-CERKL isoform multiplicity shown in mammals, the moderate transcriptional complexity in fish facilitates phenotypic studies derived from gene silencing. Moreover, of relevance to pathogenicity, teleost CERKL shares the two main human protein isoforms. Morpholino injection has been used to generate a cerkl knockdown zebrafish model. The morphant phenotype results in abnormal eye development with lamination defects, failure to develop photoreceptor outer segments, increased apoptosis of retinal cells and small eyes. Our data support that zebrafish Cerkl does not interfere with proliferation and neural differentiation during early developmental stages but is relevant for survival and protection of the retinal tissue. Overall, we propose that this zebrafish model is a powerful tool to unveil CERKL contribution to human retinal degeneration.
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Affiliation(s)
- Marina Riera
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBERER, Instituto de Salud Carlos III, Barcelona, Spain
| | - Demian Burguera
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Jordi Garcia-Fernàndez
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Roser Gonzàlez-Duarte
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- CIBERER, Instituto de Salud Carlos III, Barcelona, Spain
- * E-mail:
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Garanto A, Mandal NA, Egido-Gabás M, Marfany G, Fabriàs G, Anderson RE, Casas J, Gonzàlez-Duarte R. Specific sphingolipid content decrease in Cerkl knockdown mouse retinas. Exp Eye Res 2013; 110:96-106. [PMID: 23501591 DOI: 10.1016/j.exer.2013.03.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/19/2013] [Accepted: 03/04/2013] [Indexed: 01/12/2023]
Abstract
Sphingolipids (SPLs) are finely tuned structural compounds and bioactive molecules involved in membrane fluidity and cellular homeostasis. The core sphingolipid, ceramide (CER), and its derivatives, regulate several crucial processes in neuronal cells, among them cell differentiation, cell-cell interactions, membrane conductance, synaptic transmission, and apoptosis. Mutations in Ceramide Kinase-Like (CERKL) cause autosomal recessive Retinitis Pigmentosa and Cone Rod Dystrophy. The presence of a conserved lipid kinase domain and the overall similarity with CERK suggested that CERKL might play a role in the SPL metabolism as a CER kinase. Unfortunately, CERKL function and substrate(s), as well as its contribution to the retinal etiopathology, remain as yet unknown. In this work we aimed to characterize the mouse retinal sphingolipidome by UPLC-TOF to first, thoroughly investigate the SPL composition of the murine retina, compare it to our Cerkl -/- model, and finally assess new possible CERKL substrates by phosphorus quantification and protein-lipid overlay. Our results showed a consistent and notable decrease of the retinal SPL content (mainly ranging from 30% to 60%) in the Cerkl -/- compared to WT retinas, which was particularly evident in the glucosyl/galactosyl ceramide species (Glc/GalCer) whereas the phospholipids and neutral lipids remained unaltered. Moreover, evidence in favor of CERKL binding to GlcCer, GalCer and sphingomyelin has been gathered. Altogether, these results highlight the involvement of CERKL in the SPL metabolism, question its role as a kinase, and open new scenarios concerning its function.
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Affiliation(s)
- Alejandro Garanto
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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Mandal NA, Tran JTA, Saadi A, Rahman AK, Huynh TP, Klein WH, Cho JH. Expression and localization of CERKL in the mammalian retina, its response to light-stress, and relationship with NeuroD1 gene. Exp Eye Res 2012; 106:24-33. [PMID: 23142158 DOI: 10.1016/j.exer.2012.10.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 01/30/2023]
Abstract
Mutations in the Ceramide kinase like (CERKL) gene are associated with retinitis pigmentosa (RP26) and cone-rod dystrophy. CERKL is homologous to Ceramide kinase (CERK), and its function is still unknown. The purpose of this study was to test the expression and distribution of this gene and its protein in rat and in mouse tissues, in light-stressed rat retinas and in the retinas of NeuroD1 knock-out mice to understand the role of CERKL in the retina. Expression of Cerkl and Cerk mRNA was determined by quantitative RT-PCR. Expression of the protein was determined by Western blotting with anti-CERKL antibody. Localization of the protein was determined by using immunofluorescence microscopy. With qRT-PCR, we revealed that the relative mRNA expression of Cerkl was the highest in the retina among all the rat tissue tested; it was >10-fold higher than in the brain. On the other hand, Cerk has ubiquitous expression and its relative abundance is >2 fold of Cerkl in the retina. Cerkl was expressed minimally in the developing mouse eyes and reached a peak at retinal maturity at 2 months. Western blots of retinal tissues revealed two major CERKL protein bands: 59 kDa (C1) and 37 kDa (C2). However, only C2 CERKL was found in the rat retinal rod outer segment (ROS) at level of that was not changed in light vs. dark adaptation. In the light-stressed retina, expression of Cerkl mRNA increased significantly, which was reflected in only on C2 CERKL protein. The CERKL protein localized prominently to the ganglion cells, inner nuclear layers (INL), retinal pigment epithelial (RPE) cells, and photoreceptor inner segments in the retinal sections. Nuclear localization of CERKL was not affected in RPE, INL and the ganglion cell layers in the light-stressed retina; however, the perinuclear and outer segment locations appear to be altered. In the NeuroD1 knock-out mouse retina, the expression of Cerkl mRNA and protein decreased and that decrease also pertains to C2 CERKL. In conclusion, the retina had the highest level of Cerkl mRNA and protein expression, which reached its maximum in the adult retina; CERKL localized to ROS and RPE cells and the light-adaptation did not change the level of CERKL in ROS; light-stress induced Cerkl expression in the retina; and its expression decreased in NeuroD1 knock-out retina. Thus, CERKL may be important for the stress responses and protection of photoreceptor cells.
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Affiliation(s)
- Nawajes A Mandal
- Department of Ophthalmology, OUHSC, Dean A. McGee Eye Institute, Oklahoma City, OK 73104, United States.
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Nevet MJ, Vekslin S, Dizhoor AM, Olshevskaya EV, Tidhar R, Futerman AH, Ben-Yosef T. Ceramide kinase-like (CERKL) interacts with neuronal calcium sensor proteins in the retina in a cation-dependent manner. Invest Ophthalmol Vis Sci 2012; 53:4565-74. [PMID: 22678504 DOI: 10.1167/iovs.12-9770] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE CERKL encodes for a ceramide kinase (CERK)-like protein. CERKL mutations are associated with severe retinal degeneration. Several studies have been conducted to prove a biochemical similarity between CERK and CERKL enzymatic activities. However, so far there has been no evidence that CERKL phosphorylates ceramide or any other lipid substrate in vitro or in vivo. The purpose of this work was to characterize CERKL's function by identification of CERKL-interacting proteins in the mammalian retina. METHODS CERKL-interacting proteins were identified implementing the Ras-recruitment system (RRS) on a bovine retina cDNA library. Co-immunoprecipitation (co-IP) in transfected cells and in photoreceptor outer segments was used to verify the identified interactions. Serial deletion constructs were used to map the interacting sites. CERKL's kinase activity was tested by a CERK activity assay. RESULTS We identified an interaction between CERKL and several neuronal calcium sensor (NCS) proteins, including guanylate cyclase activating protein 1 (GCAP1), GCAP2, and recoverin. These interactions were confirmed by co-IP experiments in transfected mammalian cells. Moreover, the interaction between endogenous CERKL and GCAP2 was confirmed by co-IP in photoreceptor outer segments. We found that CERKL-GCAP interaction is cation dependent and is mediated by CERKL's N-terminal region and by GCAPs cation-binding domains (EF-hands 2-4). CONCLUSIONS This study, which is the first to describe the interactions of CERKL with other retinal proteins, links CERKL to proteins involved in the photoresponse and Ca(2+) signaling, providing important clues for future research required in this direction.
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Affiliation(s)
- Mariela J Nevet
- Department of Genetics and The Rappaport Family Institute for Research in the Medical Sciences, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Garanto A, Vicente-Tejedor J, Riera M, de la Villa P, Gonzàlez-Duarte R, Blanco R, Marfany G. Targeted knockdown of Cerkl, a retinal dystrophy gene, causes mild affectation of the retinal ganglion cell layer. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1258-69. [PMID: 22549043 DOI: 10.1016/j.bbadis.2012.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 04/10/2012] [Accepted: 04/11/2012] [Indexed: 11/28/2022]
Abstract
In order to approach the function of the retinal dystrophy CERKL gene we generated a novel knockout mouse model by cre-mediated targeted deletion of the Cerkl first exon and proximal promoter. The excised genomic region (2.3kb) encompassed the first Cerkl exon, upstream sequences including the proximal promoter and the initial segment of the first intron. The Cerkl-/- mice were viable and fertile. The targeted Cerkl deletion resulted in a knockdown more than a knockout model, given that alternative promoters (unreported at that time) directed basal expression of Cerkl (35%). In situ hybridizations and immunohistochemistry showed that this remnant expression was moderate in the photoreceptors and weak in the ganglion and inner cell layers. Morphological characterization of the Cerkl-/- retinas did not show any gross structural changes, even at 12 months of age. However, some clear and consistent signals of gliosis and retinal stress were detected by the statistically significant increase of i) the glial fibrillary antigen protein (GFAP) expression, and ii) apoptosis, as detected by TUNEL. Remarkably, consistent non-progressive perturbation (from birth up to 12 months of age) of ganglion cells was supported by the decrease of the Brn3a marker expression as well as the reduced oscillatory potentials in the electroretinographic recordings. In conclusion, the Cerkl-/- knockdown shows a mild retinal phenotype, with increased levels of cellular stress and apoptosis indicators, and clear signs of functional alteration at the ganglion cell layer, but no detectable morphological changes.
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Mechtcheriakova D, Sobanov Y, Holtappels G, Bajna E, Svoboda M, Jaritz M, Bachert C, Jensen-Jarolim E. Activation-induced cytidine deaminase (AID)-associated multigene signature to assess impact of AID in etiology of diseases with inflammatory component. PLoS One 2011; 6:e25611. [PMID: 21984922 PMCID: PMC3184987 DOI: 10.1371/journal.pone.0025611] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 09/07/2011] [Indexed: 01/23/2023] Open
Abstract
Activation-induced cytidine deaminase (AID) is expressed in B cells within germinal centers and is critically involved in class switch recombination and somatic hypermutation of immunoglobulin loci. Functionally active AID can additionally be detected within ectopic follicular structures developed at sites of chronic inflammation. Furthermore, AID may target non-Ig genes in B- and non-B-cell background. Therefore, AID-associated effects are of increasing interest in disease areas such as allergy, inflammation, autoimmunity, and cancer.Pathway- or disease-relevant multigene signatures have attracted substantial attention for therapeutic target proposal, diagnostic tools, and monitoring of therapy response. To delineate the impact of AID in etiology of multifactorial diseases, we designed the AID-associated 25-gene signature. Chronic rhinosinusitis with nasal polyps was used as an inflammation-driven airway disease model; high levels of IgE have been previously shown to be present within polyp tissue. Expression levels of 16 genes were found to be modulated in polyps including AID, IgG and IgE mature transcripts which reflect AID activity; clustering algorithm revealed an AID-specific gene signature for the disease state with nasal polyp. Complementary, AID-positive ectopic lymphoid structures were detected within polyp tissues by in situ immunostaining. Our data demonstrate the class switch recombination and somatic hypermutation events likely taking place locally in the airways and in addition to the previously highlighted markers and/or targets as IL5 and IgE suggest novel candidate genes to be considered for treatment of nasal polyposis including among others IL13 and CD23. Thus, the algorithm presented herein including the multigene signature approach, analysis of co-regularities and creation of AID-associated functional network gives an integrated view of biological processes and might be further applied to assess role of altered AID expression in etiology of other diseases, in particular, aberrant immunity and cancer.
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Affiliation(s)
- Diana Mechtcheriakova
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
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Zheng S, Qiu X, Chen B, Yu X, Lin K, Bian M, Liu Z, Huang H, Yu W. Toxicity evaluation of benzo[a]pyrene on the polychaete Perinereis nuntia using subtractive cDNA libraries. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 105:279-291. [PMID: 21774909 DOI: 10.1016/j.aquatox.2011.06.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/14/2011] [Accepted: 06/21/2011] [Indexed: 05/31/2023]
Abstract
To gain insight into the toxic effects of the carcinogenic PAH benzo[a]pyrene (BaP) on the typical marine benthic polychaete Perinereis nuntia, we amplified and sequenced genes by creating subtractive cDNA libraries between worms exposed to BaP and solvent control. We assigned functions to the identified sequences and further analyzed the transcriptional profile changes of a set of 50 selected potential marker genes using quantitative real time PCR. A total of 2422 new high quality ESTs (GenBank accession number GT629654-GT632075) were obtained in the P. nuntia subtracted cDNA libraries, and assembled into 1594 unique sequences. Blastx results showed 700 of the unique sequences shared high similarity with existing genes in the GenBank nr database. Functional annotation of these enriched gene segments suggested that P. nuntia shows a wide range of toxicological responses to BaP. Comparison of the transcriptional profiles of the 50 potential marker genes in worms exposed to BaP and the control suggested that BaP significantly changed the expression of genes involved in xenobiotics metabolism, reactive oxygen species (ROS) elimination, DNA repair, apoptosis, cell division cycle, neurodegeneration, neurotransmitter metabolism and carcinogenesis. It also shows that there are significant correlations between these potential marker genes. The results support the prediction that the polychaete P. nuntia also has a set of tumor-related genes, while other responses influenced by BaP involve detoxification, antioxidation, DNA repair and apoptosis.
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Affiliation(s)
- Senlin Zheng
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, 361005, China.
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Bornancin F. Ceramide kinase: the first decade. Cell Signal 2010; 23:999-1008. [PMID: 21111813 DOI: 10.1016/j.cellsig.2010.11.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 11/16/2010] [Accepted: 11/16/2010] [Indexed: 11/20/2022]
Abstract
It has been some 20 years since the initial discovery of ceramide 1-phosphate (C1P) and nearly a decade since ceramide kinase (CERK) was cloned. Many studies have shown that C1P is important for membrane biology and for the regulation of membrane-bound proteins, and the CERK enzyme has appeared to be tightly regulated in order to control both ceramide levels and production of C1P. Furthermore, C1P made by CERK has emerged as a genuine signalling entity. However, it represents only part of the C1P pool that is available in the cell, therefore suggesting that alternative unknown C1P-producing mechanisms may also play a role. Recent technological developments for measuring complex sphingolipids in biological samples, together with the availability of Cerk-deficient animals as well as potent CERK inhibitors, have now provided new grounds for investigating C1P biology further. Here, we will review the current understanding of CERK and C1P in terms of biochemistry and functional implications, with particular attention to C1P produced by CERK.
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Affiliation(s)
- Frédéric Bornancin
- Novartis Institutes for BioMedical Research, CH-4056 Basle, Switzerland.
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Rovina P, Jaritz M, Bornancin F. Transcriptional repression of ceramide kinase in LPS-challenged macrophages. Biochem Biophys Res Commun 2010; 401:164-7. [DOI: 10.1016/j.bbrc.2010.09.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Accepted: 09/09/2010] [Indexed: 11/25/2022]
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Gangoiti P, Camacho L, Arana L, Ouro A, Granado MH, Brizuela L, Casas J, Fabriás G, Abad JL, Delgado A, Gómez-Muñoz A. Control of metabolism and signaling of simple bioactive sphingolipids: Implications in disease. Prog Lipid Res 2010; 49:316-34. [PMID: 20193711 DOI: 10.1016/j.plipres.2010.02.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/18/2010] [Accepted: 02/22/2010] [Indexed: 01/05/2023]
Abstract
Simple bioactive sphingolipids include ceramide, sphingosine and their phosphorylated forms sphingosine 1-phosphate and ceramide 1-phosphate. These molecules are crucial regulators of cell functions. In particular, they play important roles in the regulation of angiogenesis, apoptosis, cell proliferation, differentiation, migration, and inflammation. Decoding the mechanisms by which these cellular functions are regulated requires detailed understanding of the signaling pathways that are implicated in these processes. Most importantly, the development of inhibitors of the enzymes involved in their metabolism may be crucial for establishing new therapeutic strategies for treatment of disease.
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Affiliation(s)
- Patricia Gangoiti
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Bilbao, Spain
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Arana L, Gangoiti P, Ouro A, Trueba M, Gómez-Muñoz A. Ceramide and ceramide 1-phosphate in health and disease. Lipids Health Dis 2010; 9:15. [PMID: 20137073 PMCID: PMC2828451 DOI: 10.1186/1476-511x-9-15] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 02/05/2010] [Indexed: 01/06/2023] Open
Abstract
Sphingolipids are essential components of cell membranes, and many of them regulate vital cell functions. In particular, ceramide plays crucial roles in cell signaling processes. Two major actions of ceramides are the promotion of cell cycle arrest and the induction of apoptosis. Phosphorylation of ceramide produces ceramide 1-phosphate (C1P), which has opposite effects to ceramide. C1P is mitogenic and has prosurvival properties. In addition, C1P is an important mediator of inflammatory responses, an action that takes place through stimulation of cytosolic phospholipase A2, and the subsequent release of arachidonic acid and prostaglandin formation. All of the former actions are thought to be mediated by intracellularly generated C1P. However, the recent observation that C1P stimulates macrophage chemotaxis implicates specific plasma membrane receptors that are coupled to Gi proteins. Hence, it can be concluded that C1P has dual actions in cells, as it can act as an intracellular second messenger to promote cell survival, or as an extracellular receptor agonist to stimulate cell migration.
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Affiliation(s)
- Lide Arana
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
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Gómez-Muñoz A, Gangoiti P, Granado MH, Arana L, Ouro A. Ceramide-1-Phosphate in Cell Survival and Inflammatory Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:118-30. [DOI: 10.1007/978-1-4419-6741-1_8] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Gault CR, Obeid LM, Hannun YA. An overview of sphingolipid metabolism: from synthesis to breakdown. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:1-23. [PMID: 20919643 DOI: 10.1007/978-1-4419-6741-1_1] [Citation(s) in RCA: 727] [Impact Index Per Article: 51.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sphingolipids constitute a class of lipids defined by their eighteen carbon amino-alcohol backbones which are synthesized in the ER from nonsphingolipid precursors. Modification of this basic structure is what gives rise to the vast family of sphingolipids that play significant roles in membrane biology and provide many bioactive metabolites that regulate cell function. Despite the diversity of structure and function of sphingolipids, their creation and destruction are governed by common synthetic and catabolic pathways. In this regard, sphingolipid metabolism can be imagined as an array of interconnected networks that diverge from a single common entry point and converge into a single common breakdown pathway. In their simplest forms, sphingosine, phytosphingosine and dihydrosphingosine serve as the backbones upon which further complexity is achieved. For example, phosphorylation of the C1 hydroxyl group yields the final breakdown products and/or the important signaling molecules sphingosine-1-phosphate, phytosphingosine-1-phosphate and dihydrosphingosine-1-phosphate, respectively. On the other hand, acylation of sphingosine, phytosphingosine, or dihydrosphingosine with one of several possible acyl CoA molecules through the action of distinct ceramide synthases produces the molecules defined as ceramide, phytoceramide, or dihydroceramide. Ceramide, due to the differing acyl CoAs that can be used to produce it, is technically a class of molecules rather than a single molecule and therefore may have different biological functions depending on the acyl chain it is composed of. At the apex of complexity is the group of lipids known as glycosphingolipids (GSL) which contain dozens of different sphingolipid species differing by both the order and type of sugar residues attached to their headgroups. Since these molecules are produced from ceramide precursors, they too may have differences in their acyl chain composition, revealing an additional layer of variation. The glycosphingolipids are divided broadly into two categories: glucosphingolipids and galactosphingolipids. The glucosphingolipids depend initially on the enzyme glucosylceramide synthase (GCS) which attaches glucose as the first residue to the C1 hydroxyl position. Galactosphingolipids, on the other hand, are generated from galactosylceramide synthase (GalCerS), an evolutionarily dissimilar enzyme from GCS. Glycosphingolipids are further divided based upon further modification by various glycosyltransferases which increases the potential variation in lipid species by several fold. Far more abundant are the sphingomyelin species which are produced in parallel with glycosphingolipids, however they are defined by a phosphocholine headgroup rather than the addition of sugar residues. Although sphingomyelin species all share a common headgroup, they too are produced from a variety of ceramide species and therefore can have differing acyl chains attached to their C-2 amino groups. Whether or not the differing acyl chain lengths in SMs dictate unique functions or important biophysical distinctions has not yet been established. Understanding the function of all the existing glycosphingolipids and sphingomyelin species will be a major undertaking in the future since the tools to study and measure these species are only beginning to be developed (see Fig 1 for an illustrated depiction of the various sphingolipid structures). The simple sphingolipids serve both as the precursors and the breakdown products of the more complex ones. Importantly, in recent decades, these simple sphingolipids have gained attention for having significant signaling and regulatory roles within cells. In addition, many tools have emerged to measure the levels of simple sphingolipids and therefore have become the focus of even more intense study in recent years. With this thought in mind, this chapter will pay tribute to the complex sphingolipids, but focus on the regulation of simple sphingolipid metabolism.
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Affiliation(s)
- Christopher R Gault
- Department of Biochemistry, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Chen WQ, Graf C, Zimmel D, Rovina P, Krapfenbauer K, Jaritz M, Parker PJ, Lubec G, Bornancin F. Ceramide Kinase Profiling by Mass Spectrometry Reveals a Conserved Phosphorylation Pattern Downstream of the Catalytic Site. J Proteome Res 2009; 9:420-9. [DOI: 10.1021/pr900763z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wei-Qiang Chen
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Christine Graf
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - David Zimmel
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Philipp Rovina
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Kurt Krapfenbauer
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Markus Jaritz
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Peter J. Parker
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Gert Lubec
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
| | - Frédéric Bornancin
- Department of Pediatrics, Medical University of Vienna, Waehringer Guertel 18, A-1090, Vienna, Austria, Novartis Institutes for BioMedical Research (NIBR), Vienna, Brunnerstrasse 59, A-1235 Vienna, Austria, Protein Phosphorylation Laboratory, London Research Institute, Cancer Research U.K., London, WC2A 3PX, United Kingdom, and the Division of Cancer Studies King’s College London, New Hunt’s House, Guy’s Hospital, St Thomas Street, London SE1 1UL, United Kingdom
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Whole genome association study identifies polymorphisms associated with QT prolongation during iloperidone treatment of schizophrenia. Mol Psychiatry 2009; 14:1024-31. [PMID: 18521091 DOI: 10.1038/mp.2008.52] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Administration of certain drugs (for example, antiarrhythmics, antihistamines, antibiotics, antipsychotics) may occasionally affect myocardial repolarization and cause prolongation of the QT interval. We performed a whole genome association study of drug-induced QT prolongation after 14 days of treatment in a phase 3 clinical trial evaluating the efficacy, safety and tolerability of a novel atypical antipsychotic, iloperidone, in patients with schizophrenia. We identified DNA polymorphisms associated with QT prolongation in six loci, including the CERKL and SLCO3A1 genes. Each single nucleotide polymorphism (SNP) defined two genotype groups associated with a low mean QT change (ranging from -0.69 to 5.67 ms depending on the SNP) or a higher mean QT prolongation (ranging from 14.16 to 17.81 ms). The CERKL protein is thought to be part of the ceramide pathway, which regulates currents conducted by various potassium channels, including the hERG channel. It is well established that inhibition of the hERG channel can prolong the QT interval. SLCO3A1 is thought to play a role in the translocation of prostaglandins, which have known cardioprotective properties, including the prevention of torsades de pointes. Our findings also point to genes involved in myocardial infarction (PALLD), cardiac structure and function (BRUNOL4) and cardiac development (NRG3). Results of this pharmacogenomic study provide new insight into the clinical response to iloperidone, developed with the goal of directing therapy to those patients with the optimal benefit/risk ratio.
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Rovina P, Schanzer A, Graf C, Mechtcheriakova D, Jaritz M, Bornancin F. Subcellular localization of ceramide kinase and ceramide kinase-like protein requires interplay of their Pleckstrin Homology domain-containing N-terminal regions together with C-terminal domains. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:1023-30. [PMID: 19501188 DOI: 10.1016/j.bbalip.2009.05.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/15/2009] [Accepted: 05/29/2009] [Indexed: 01/14/2023]
Abstract
Ceramide kinase (CERK) and the ceramide kinase-like protein (CERKL), two related members of the diacylglycerol kinase family, are ill-defined at the molecular level. In particular, what determines their distinctive subcellular localization is not well understood. Here we show that the Pleckstrin Homology (PH) domain of CERK, which is required for Golgi complex localization, can substitute for the N-terminal region of CERKL and allow for wild-type CERKL localization, which is typified by nucleolar accumulation. This demonstrates that determinants for localization of these two enzymes do not lie solely in their PH domain-containing N-terminal regions. Moreover, we present evidence for a previously unrecognized participation of CERK distal sequences in structural stability, localization and activity of the full-length protein. Progressive deletion of CERK and CERKL from the C-terminus revealed similar sequential organization in both proteins, with nuclear import signals in their N-terminal part, and nuclear export signals in their C-terminal part. Furthermore, mutagenesis of individual cysteine residues of a CERK-specific CXXXCXXC motif severely compromised both exportation of CERK from the nucleus and its association with the Golgi complex. Altogether, this work identifies conserved domains in CERK and CERKL as well as new determinants for their subcellular localization. It further suggests a nucleocytoplasmic shuttling mechanism for both proteins that may be defective in CERKL mutant proteins responsible for retinal degenerative diseases.
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Affiliation(s)
- Philipp Rovina
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
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41
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Rajan R, Mathew T, Buffa R, Bornancin F, Cavallari M, Nussbaumer P, De Libero G, Vasella A. Synthesis and Evaluation ofN-Acetyl-2-amino-2-deoxy-α-D-galactosyl 1-Thio-7-oxaceramide, a New Analogue ofα-D-Galactosyl Ceramide. Helv Chim Acta 2009. [DOI: 10.1002/hlca.200800454] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Graf C, Zemann B, Rovina P, Urtz N, Schanzer A, Reuschel R, Mechtcheriakova D, Müller M, Fischer E, Reichel C, Huber S, Dawson J, Meingassner JG, Billich A, Niwa S, Badegruber R, Van Veldhoven PP, Kinzel B, Baumruker T, Bornancin F. Neutropenia with impaired immune response to Streptococcus pneumoniae in ceramide kinase-deficient mice. THE JOURNAL OF IMMUNOLOGY 2008; 180:3457-66. [PMID: 18292572 DOI: 10.4049/jimmunol.180.5.3457] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In mammals, ceramide kinase (CerK)-mediated phosphorylation of ceramide is the only known pathway to ceramide-1-phosphate (C1P), a recently identified signaling sphingolipid metabolite. To help delineate the roles of CerK and C1P, we knocked out the gene of CerK in BALB/c mice by homologous recombination. All in vitro as well as cell-based assays indicated that CerK activity is completely abolished in Cerk-/- mice. Labeling with radioactive orthophosphate showed a profound reduction in the levels of de novo C1P formed in Cerk-/- macrophages. Consistently, mass spectrometry analysis revealed a major contribution of CerK to the formation of C16-C1P. However, the significant residual C1P levels in Cerk-/- animals indicate that alternative routes to C1P exist. Furthermore, serum levels of proapoptotic ceramide in these animals were significantly increased while levels of dihydroceramide as the biosynthetic precursor were reduced. Previous literature pointed to a role of CerK or C1P in innate immune cell function. Using a variety of mechanistic and disease models, as well as primary cells, we found that macrophage- and mast cell-dependent readouts are barely affected in the absence of CerK. However, the number of neutrophils was strikingly reduced in blood and spleen of Cerk-/- animals. When tested in a model of fulminant pneumonia, Cerk-/- animals developed a more severe disease, lending support to a defect in neutrophil homeostasis following CerK ablation. These results identify ceramide kinase as a key regulator of C1P, dihydroceramide and ceramide levels, with important implications for neutrophil homeostasis and innate immunity regulation.
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Affiliation(s)
- Christine Graf
- Novartis Institutes for BioMedical Research, Vienna, Austria
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Lidome E, Graf C, Jaritz M, Schanzer A, Rovina P, Nikolay R, Bornancin F. A conserved cysteine motif essential for ceramide kinase function. Biochimie 2008; 90:1560-5. [PMID: 18662741 DOI: 10.1016/j.biochi.2008.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 07/03/2008] [Indexed: 11/18/2022]
Abstract
Ceramide kinase (CerK) is a sphingolipid metabolizing enzyme very sensitive to oxidation; however, the determinants are unknown. We show here that the thiol-modifying agent N-ethyl-maleimide abrogates CerK activity in vitro and in a cell based assay, implying that important cysteine residues are accessible in purified as well as endogenous CerK. We replaced every 22 residues in human CerK, by an alanine, and measured activity in the resulting mutant proteins. This led to identification of a cluster of cysteines, C(347)XXXC(351)XXC(354), essential for CerK function. These findings are discussed based on homology modeling of the catalytic domain of CerK.
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Affiliation(s)
- Emilie Lidome
- Novartis Institutes for BioMedical Research, Vienna, Vienna, Austria
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Graf C, Niwa S, Müller M, Kinzel B, Bornancin F. Wild-type levels of ceramide and ceramide-1-phosphate in the retina of ceramide kinase-like-deficient mice. Biochem Biophys Res Commun 2008; 373:159-63. [PMID: 18555012 DOI: 10.1016/j.bbrc.2008.06.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 06/04/2008] [Indexed: 11/18/2022]
Abstract
Ceramide kinase-like (CerkL) is the most recently identified member of the sphingolipid metabolizing enzyme family. This protein is believed to have ceramide kinase (CerK) activity; however, this has not been clarified yet. We generated CerkL-deficient (CerkL(-/-)) mice, measured ceramide (Cer) and ceramide-1-phosphate (C1P) levels in isolated retina, and compared them to levels measured in Cerk(-/-) and WT retinas. We also labeled CerkL(-/-), Cerk(-/-), and WT retinas with (33)P orthophosphate to measure and compare de novo phosphorylation of Cer. Whereas Cerk(-/-) retinas displayed decreased C1P and enhanced Cer, and lacked the capacity to phosphorylate Cer, CerkL(-/-) retinas were indistinguishable from WT retinas with regard to Cer and C1P levels, and in their ability to phosphorylate Cer. Altogether, our results do not support the hypothesis that CerkL is a second CerK enzyme impacting on Cer levels in the retina. CerkL, if active enzymatically, might use a novel, not yet described, lipid substrate.
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Affiliation(s)
- Christine Graf
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
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Don AS, Rosen H. A fluorescent plate reader assay for ceramide kinase. Anal Biochem 2007; 375:265-71. [PMID: 18206978 DOI: 10.1016/j.ab.2007.12.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 12/20/2007] [Accepted: 12/20/2007] [Indexed: 01/27/2023]
Abstract
Ceramide kinase and its product ceramide 1-phosphate have been implicated in cellular proliferation and survival, activation of cytosolic phospholipase A(2), mast cell degranulation, and phagocytosis. Current assays for ceramide kinase activity employ [(32)P]ATP, with separation of labeled product from excess ATP by organic extraction and thin-layer chromatography. We have developed a fluorescent plate reader assay for ceramide kinase that uses commercially available C6-NBD ceramide (N-{6-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]hexanoyl}-D-erythro-sphingosine). Our assay is based on the differential partitioning of substrate and product following a single chloroform/methanol extraction. The product, which partitions into the aqueous phase at physiological pH, is quantitated directly in a plate reader. The substrate may be delivered using either fatty acid-free albumin or detergent/lipid mixed micelles, and we have found that the use of albumin rather than detergent micelles allows one to detect lipid interactions with the enzyme that might otherwise go unnoticed. Our method is useful for assaying ceramide kinase activity both in vitro and in cultured cells, and it offers several advantages over the conventional assay, including greater speed, the ability to run a larger number of assay replicates at one time, and the elimination of environmental and safety issues associated with the use of radioactive materials.
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Affiliation(s)
- Anthony S Don
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, USA
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46
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Boath A, Graf C, Lidome E, Ullrich T, Nussbaumer P, Bornancin F. Regulation and traffic of ceramide 1-phosphate produced by ceramide kinase: comparative analysis to glucosylceramide and sphingomyelin. J Biol Chem 2007; 283:8517-26. [PMID: 18086664 DOI: 10.1074/jbc.m707107200] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Ceramide 1-phosphate (C1P) has been characterized as a sphingolipid that participates in cell signaling. Although C1P synthesis is thought to occur via phosphorylation of ceramide by ceramide kinase (CerK), the processes that regulate C1P formation and fate remain largely unknown. In this study we analyzed bone marrow-derived macrophages (BMDM) from CerK-null mice (Cerk(-/-)) and found significant levels of C1P, suggesting that previously unrecognized pathways may also lead to C1P formation. After these experiments we used an overexpression system, BMDM from Cerk(-/-) mice, and short-chain fluorescent ceramides to trace CerK-dependent formation of C1P. Because the ceramide analogs can also be converted to glucosylceramide (GlcCer) and sphingomyelin (SM), they allowed us to directly compare all three metabolites. We found that C1P produced by CerK is turned over rapidly when serum is removed or upon calcium chelation, whereas GlcCer and SM are stable under these conditions. We further demonstrated that ceramide must be transported to the Golgi complex to be phosphorylated by CerK. Inhibition of the ceramide transfer protein slowed down SM formation without decreasing C1P, suggesting an alternate route of ceramide transport. Other experiments indicated that, like GlcCer and SM, C1P traffics along the secretory pathway to reach the plasma membrane. Furthermore, in BMDM C1P was secreted more readily than was GlcCer or SM. Altogether, our results indicate that CerK is essential to C1P formation via phosphorylation of Cer, providing the first insights into mechanisms underlying ceramide access to CerK and C1P trafficking as well as clarifying C1P as a signaling entity.
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Affiliation(s)
- Alistair Boath
- Novartis Institutes for BioMedical Research, Vienna, Brunnerstrasse 59, Wien, Austria
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47
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Graf C, Rovina P, Tauzin L, Schanzer A, Bornancin F. Enhanced ceramide-induced apoptosis in ceramide kinase overexpressing cells. Biochem Biophys Res Commun 2007; 354:309-14. [PMID: 17222802 DOI: 10.1016/j.bbrc.2006.12.208] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Accepted: 12/30/2006] [Indexed: 12/22/2022]
Abstract
We evaluated how increased levels of ceramide kinase (CerK) would impact the growth of COS-1 fibroblasts and RBL-2H3 basophils. The low CerK activity in these cells was strongly up-regulated upon recombinant expression of CerK. CerK-overexpressing COS-1 cells depended on higher concentrations of serum for their growth and displayed many filipodia. The two CerK-overexpressing cell lines were more sensitive to C2-ceramide-mediated apoptosis, and this correlated with the production of C2-ceramide-1-phosphate by CerK. This study indicates that ceramide kinase may participate in the control of cell growth, and establishes a novel assay that will be valuable for testing ceramide kinase inhibitors.
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Affiliation(s)
- Christine Graf
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
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48
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Munagala N, Nguyen S, Lam W, Lee J, Joly A, McMillan K, Zhang W. Identification of Small Molecule Ceramide Kinase Inhibitors Using A Homogeneous Chemiluminescence High Throughput Assay. Assay Drug Dev Technol 2007; 5:65-73. [PMID: 17355200 DOI: 10.1089/adt.2006.046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lipid kinases have emerged as potentially important therapeutic targets in oncology and inflammation. Ceramide kinase (CERK) is a lipid kinase that catalyzes the formation of ceramide-1-phosphate from ceramide, a sphingolipid that is a key mediator of cellular apoptosis. Ceramide-1-phosphate has been shown to enhance the production of pro-inflammatory eicosonoids, to promote cell proliferation, and potentially to reduce intracellular ceramide levels by inhibition of acidic sphingomyelinases. Here we describe a homogeneous chemiluminescence assay that directly measures the ceramide-dependent ATP depletion by recombinant full-length human CERK. As compared to reported CERK assays that have limitations on compound throughput, the chemiluminescence assay has been miniaturized to a 1,536-well microtiter plate format and utilized to screen an ultra-large compound library (>4 million compounds). Multiple chemical scaffolds have been identified as CERK kinase inhibitors and characterized mechanistically, which to our knowledge represent the first known small molecule CERK inhibitors with nanomolar activities. These compounds can serve as tools to further elucidate the CERK pathway and its role in ceramide metabolism and human diseases.
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Marcu AC, Chalfant CE. Ceramide-1-phosphate, a new bioactive sphingolipid in regulating cell signaling. ACTA ACUST UNITED AC 2007. [DOI: 10.2217/17460875.2.1.75] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rovina P, Jaritz M, Höfinger S, Graf C, Dévay P, Billich A, Baumruker T, Bornancin F. A critical beta6-beta7 loop in the pleckstrin homology domain of ceramide kinase. Biochem J 2006; 400:255-65. [PMID: 16872273 PMCID: PMC1652822 DOI: 10.1042/bj20060316] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
CerK (ceramide kinase) produces ceramide 1-phosphate, a sphingophospholipid with recognized signalling properties. It localizes to the Golgi complex and fractionates essentially between detergent-soluble and -insoluble fractions; however, the determinants are unknown. Here, we made a detailed mutagenesis study of the N-terminal PH domain (pleckstrin homology domain) of CerK, based on modelling, and identified key positively charged amino acid residues within an unusual motif in the loop interconnecting beta-strands 6 and 7. These residues are critical for CerK membrane association and polyphosphoinositide binding and activity. Their mutagenesis results in increased thermolability, sensitivity to proteolysis, reduced apparent molecular mass as well as propensity of the recombinant mutant protein to aggregate, indicating that this loop impacts the overall conformation of the CerK protein. This is in contrast with most PH domains whose function strongly relies on charges located in the beta1-beta2 loop.
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Affiliation(s)
- Philipp Rovina
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Markus Jaritz
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Siegfried Höfinger
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Christine Graf
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Piroska Dévay
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Andreas Billich
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Thomas Baumruker
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
| | - Frédéric Bornancin
- Novartis Institutes for BioMedical Research, Brunnerstrasse 59, A-1235 Vienna, Austria
- To whom correspondence should be addressed (email )
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