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Kim HJ, Lee PCW, Hong JH. Overview of cellular homeostasis-associated nuclear envelope lamins and associated input signals. Front Cell Dev Biol 2023; 11:1173514. [PMID: 37250905 PMCID: PMC10213260 DOI: 10.3389/fcell.2023.1173514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/03/2023] [Indexed: 05/31/2023] Open
Abstract
With the discovery of the role of the nuclear envelope protein lamin in human genetic diseases, further diverse roles of lamins have been elucidated. The roles of lamins have been addressed in cellular homeostasis including gene regulation, cell cycle, cellular senescence, adipogenesis, bone remodeling as well as modulation of cancer biology. Features of laminopathies line with oxidative stress-associated cellular senescence, differentiation, and longevity and share with downstream of aging-oxidative stress. Thus, in this review, we highlighted various roles of lamin as key molecule of nuclear maintenance, specially lamin-A/C, and mutated LMNA gene clearly reveal aging-related genetic phenotypes, such as enhanced differentiation, adipogenesis, and osteoporosis. The modulatory roles of lamin-A/C in stem cell differentiation, skin, cardiac regulation, and oncology have also been elucidated. In addition to recent advances in laminopathies, we highlighted for the first kinase-dependent nuclear lamin biology and recently developed modulatory mechanisms or effector signals of lamin regulation. Advanced knowledge of the lamin-A/C proteins as diverse signaling modulators might be biological key to unlocking the complex signaling of aging-related human diseases and homeostasis in cellular process.
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Affiliation(s)
- Hyeong Jae Kim
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Republic of Korea
| | - Peter C. W. Lee
- Lung Cancer Research Center, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea
| | - Jeong Hee Hong
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Republic of Korea
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2
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Liu T, Yu J, Ge C, Zhao F, Chen J, Miao C, Jin W, Zhou Q, Geng Q, Lin H, Tian H, Chen T, Xie H, Cui Y, Yao M, Xiao X, Li J, Li H. Sperm associated antigen 4 promotes SREBP1-mediated de novo lipogenesis via interaction with lamin A/C and contributes to tumor progression in hepatocellular carcinoma. Cancer Lett 2022; 536:215642. [PMID: 35307486 DOI: 10.1016/j.canlet.2022.215642] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/22/2022] [Accepted: 03/10/2022] [Indexed: 12/11/2022]
Abstract
Hepatocellular carcinoma (HCC) is a highly malignant tumor and its progression is associated with altered lipid metabolism in precancerous lesions, such as non-alcoholic fatty liver disease. Here, we identified sperm associated antigen 4 (SPAG4), and explored its oncogenic role in HCC progression. Database analysis and immunohistochemistry indicated increased level of SPAG4 in HCC tissues which was of prognostic value. Gain/loss-of-function experiments showed that SPAG4 exerted oncogenic roles in HCC growth both in vitro and in vivo. RNA sequencing revealed activation of a lipogenic state and SREBP1-mediated pathway following SPAG4 overexpression. Mechanistically, the N-terminal region of SPAG4 bound to lamin A/C, which increased SREBP1 expression, nuclear translocation, and transcriptional activity. Treatment with orlistat, a lipid synthesis inhibitor, reversed SPAG4-mediated oncogenic effects, and its efficacy varied with SPAG4 level. The effect of orlistat was further amplified when combined with sorafenib in tumor xenograft mouse models. Our study provides evidence that SPAG4 mediates HCC progression by affecting lipid metabolism. Administration of orlistat combined with sorafenib reverses SPAG4-mediated oncogenesis in HCC cells and ectopic xenograft tumors in mice, suggesting that this pathway represents a potential target for HCC treatment.
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Affiliation(s)
- Tengfei Liu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China; Department of Oncology, Ren ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Junming Yu
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Chao Ge
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Fangyu Zhao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Jing Chen
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Chunxiao Miao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Wenjiao Jin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Qingqing Zhou
- Department of Oncology, Rui jin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200020, China
| | - Qin Geng
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Hechun Lin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Hua Tian
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Taoyang Chen
- Qi Dong Liver Cancer Institute, Qi Dong, 226200, China
| | - Haiyang Xie
- Department of General Surgery, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
| | - Ying Cui
- Cancer Institute of Guangxi, Nanning, 530027, China
| | - Ming Yao
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Xiuying Xiao
- Department of Oncology, Ren ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Jinjun Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China
| | - Hong Li
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China.
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Rochford JJ. When Adipose Tissue Lets You Down: Understanding the Functions of Genes Disrupted in Lipodystrophy. Diabetes 2022; 71:589-598. [PMID: 35316838 DOI: 10.2337/dbi21-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022]
Abstract
Lipodystrophy syndromes are conditions in which the adipose tissue mass of an individual is altered inappropriately. The change in adipose mass can range from a relatively modest and subtle redistribution in some individuals with partial lipodystrophy to a near-complete absence of adipose tissue in the most severe forms of generalized lipodystrophy. The common feature is a disconnection between the need of the individual for a safe, healthy lipid storage capacity and the available adipose mass to perform this critical role. The inability to partition lipids for storage in appropriately functioning adipocytes leads to lipid accumulation in other tissues, which typically results in conditions such as diabetes, dyslipidemia, fatty liver, and cardiovascular disease. Several genes have been identified whose disruption leads to inherited forms of lipodystrophy. There is a link between some of these genes and adipose dysfunction, so the molecular basis of disease pathophysiology appears clear. However, for other lipodystrophy genes, it is not evident why their disruption should affect adipose development or function or, in the case of partial lipodystrophy, why only some adipose depots should be affected. Elucidating the molecular functions of these genes and their cellular and physiological effects has the capacity to uncover fundamental new insights regarding the development and functions of adipose tissue. This information is also likely to inform better management of lipodystrophy and improved treatments for patients. In addition, the findings will often be relevant to other conditions featuring adipose tissue dysfunction, including the more common metabolic disease associated with obesity.
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Echarri A. A Multisensory Network Drives Nuclear Mechanoadaptation. Biomolecules 2022; 12:biom12030404. [PMID: 35327596 PMCID: PMC8945967 DOI: 10.3390/biom12030404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/24/2022] [Accepted: 02/26/2022] [Indexed: 12/03/2022] Open
Abstract
Cells have adapted to mechanical forces early in evolution and have developed multiple mechanisms ensuring sensing of, and adaptation to, the diversity of forces operating outside and within organisms. The nucleus must necessarily adapt to all types of mechanical signals, as its functions are essential for virtually all cell processes, many of which are tuned by mechanical cues. To sense forces, the nucleus is physically connected with the cytoskeleton, which senses and transmits forces generated outside and inside the cell. The nuclear LINC complex bridges the cytoskeleton and the nuclear lamina to transmit mechanical information up to the chromatin. This system creates a force-sensing macromolecular complex that, however, is not sufficient to regulate all nuclear mechanoadaptation processes. Within the nucleus, additional mechanosensitive structures, including the nuclear envelope and the nuclear pore complex, function to regulate nuclear mechanoadaptation. Similarly, extra nuclear mechanosensitive systems based on plasma membrane dynamics, mechanotransduce information to the nucleus. Thus, the nucleus has the intrinsic structural components needed to receive and interpret mechanical inputs, but also rely on extra nuclear mechano-sensors that activate nuclear regulators in response to force. Thus, a network of mechanosensitive cell structures ensures that the nucleus has a tunable response to mechanical cues.
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Affiliation(s)
- Asier Echarri
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Mechanoadaptation and Caveolae Biology Laboratory, Areas of Cell & Developmental Biology, Calle Melchor Fernández Almagro, 3, 28029 Madrid, Spain
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Transcription of the Envelope Protein by 1-L Protein–RNA Recognition Code Leads to Genes/Proteins That Are Relevant to the SARS-CoV-2 Life Cycle and Pathogenesis. Curr Issues Mol Biol 2022; 44:791-816. [PMID: 35723340 PMCID: PMC8928949 DOI: 10.3390/cimb44020055] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/21/2022] [Accepted: 02/03/2022] [Indexed: 12/02/2022] Open
Abstract
The theoretical protein–RNA recognition code was used in this study to research the compatibility of the SARS-CoV-2 envelope protein (E) with mRNAs in the human transcriptome. According to a review of the literature, the spectrum of identified genes showed that the virus post-transcriptionally promotes or represses the genes involved in the SARS-CoV-2 life cycle. The identified genes/proteins are also involved in adaptive immunity, in the function of the cilia and wound healing (EMT and MET) in the pulmonary epithelial tissue, in Alzheimer’s and Parkinson’s disease and in type 2 diabetes. For example, the E-protein promotes BHLHE40, which switches off the IL-10 inflammatory “brake” and inhibits antiviral THαβ cells. In the viral cycle, E supports the COPII-SCAP-SREBP-HSP90α transport complex by the lowering of cholesterol in the ER and by the repression of insulin signaling, which explains the positive effect of HSP90 inhibitors in COVID-19 (geldanamycin), and E also supports importin α/β-mediated transport to the nucleus, which explains the positive effect of ivermectin, a blocker of importins α/β. In summary, transcription of the envelope protein by the 1-L protein–RNA recognition code leads to genes/proteins that are relevant to the SARS-CoV-2 life cycle and pathogenesis.
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Charar C, Metsuyanim-Cohen S, Bar DZ. Lamin regulates the dietary restriction response via the mTOR pathway in Caenorhabditis elegans. J Cell Sci 2021; 134:272061. [PMID: 34383046 PMCID: PMC8445603 DOI: 10.1242/jcs.258428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/30/2021] [Indexed: 11/30/2022] Open
Abstract
Animals subjected to dietary restriction (DR) have reduced body size, low fecundity, slower development, lower fat content and longer life span. We identified lamin as a regulator of multiple dietary restriction phenotypes. Downregulation of lmn-1, the single Caenorhabditis elegans lamin gene, increased animal size and fat content specifically in DR animals. The LMN-1 protein acts in the mTOR pathway, upstream of RAPTOR and S6 kinase β1 (S6K), a key component of and target of the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1), respectively. DR excludes the mTORC1 activator RAGC-1 from the nucleus. Downregulation of lmn-1 restores RAGC-1 to the nucleus, a necessary step for the activation of the mTOR pathway. These findings further link lamin to metabolic regulation. Summary: Downregulation of the single C. elegans lamin gene increases animal size and fat content specifically in dietary restricted animals. The lamin protein acts in the mTOR pathway to regulate these phenotypes.
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Affiliation(s)
- Chayki Charar
- The School of Dental Medicine, The Faculty of Medicine, Tel Aviv University, Israel.,The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | | | - Daniel Z Bar
- The School of Dental Medicine, The Faculty of Medicine, Tel Aviv University, Israel
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Varlet AA, Helfer E, Badens C. Molecular and Mechanobiological Pathways Related to the Physiopathology of FPLD2. Cells 2020; 9:cells9091947. [PMID: 32842478 PMCID: PMC7565540 DOI: 10.3390/cells9091947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 12/15/2022] Open
Abstract
Laminopathies are rare and heterogeneous diseases affecting one to almost all tissues, as in Progeria, and sharing certain features such as metabolic disorders and a predisposition to atherosclerotic cardiovascular diseases. These two features are the main characteristics of the adipose tissue-specific laminopathy called familial partial lipodystrophy type 2 (FPLD2). The only gene that is involved in FPLD2 physiopathology is the LMNA gene, with at least 20 mutations that are considered pathogenic. LMNA encodes the type V intermediate filament lamin A/C, which is incorporated into the lamina meshwork lining the inner membrane of the nuclear envelope. Lamin A/C is involved in the regulation of cellular mechanical properties through the control of nuclear rigidity and deformability, gene modulation and chromatin organization. While recent studies have described new potential signaling pathways dependent on lamin A/C and associated with FPLD2 physiopathology, the whole picture of how the syndrome develops remains unknown. In this review, we summarize the signaling pathways involving lamin A/C that are associated with the progression of FPLD2. We also explore the links between alterations of the cellular mechanical properties and FPLD2 physiopathology. Finally, we introduce potential tools based on the exploration of cellular mechanical properties that could be redirected for FPLD2 diagnosis.
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Affiliation(s)
- Alice-Anaïs Varlet
- Marseille Medical Genetics (MMG), INSERM, Aix Marseille University, 13005 Marseille, France;
| | - Emmanuèle Helfer
- Centre Interdisciplinaire de Nanoscience de Marseille (CINAM), CNRS, Aix Marseille University, 13009 Marseille, France
- Correspondence: (E.H.); (C.B.); Tel.: +33-6-60-30-28-91 (E.H.); +33-4-91-78-68-94 (C.B.)
| | - Catherine Badens
- Marseille Medical Genetics (MMG), INSERM, Aix Marseille University, 13005 Marseille, France;
- Correspondence: (E.H.); (C.B.); Tel.: +33-6-60-30-28-91 (E.H.); +33-4-91-78-68-94 (C.B.)
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Arumugam MK, Talawar S, Listenberger L, Donohue TM, Osna NA, Kharbanda KK. Role of Elevated Intracellular S-Adenosylhomocysteine in the Pathogenesis of Alcohol-Related Liver Disease. Cells 2020; 9:cells9061526. [PMID: 32585865 PMCID: PMC7349643 DOI: 10.3390/cells9061526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/19/2020] [Accepted: 06/21/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The earliest manifestation of alcohol-related liver disease (ALD) is steatosis, characterized by the accumulation of lipid droplets (LDs) in hepatocytes. Findings from our laboratory have indicated that many pathological changes, including steatosis, correlate with the alcohol-induced hepatocellular increases in S-adenosylhomocysteine (SAH). Based on these considerations, we hypothesized that an experimental increase in intracellular SAH alone will result in similar steatotic changes to those seen after alcohol exposure. METHODS Freshly isolated rat hepatocytes grown on collagen-coated plates were exposed to serum-free medium containing 50 µmol/L oleic acid and varying concentrations of 3-deazaadenosine (DZA) to experimentally elevate intracellular SAH levels. RESULTS Overnight exposure to DZA treatment dose-dependently increased hepatocellular triglyceride accumulation, which was also evident by morphological visualization of larger-sized LDs. The rise in triglycerides and LDs accompanied increases in mRNA and protein levels of several LD-associated proteins known to regulate LD number and size. Furthermore, DZA treatment caused a decline in the levels of lipases that prevent fat accumulation as well as increased the expression of factors involved in lipogenesis and fatty acid mobilization. Collectively, our results indicate that the elevation of intracellular SAH is sufficient to promote fat accumulation in hepatocytes, which is similar to that seen after alcohol exposure.
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Affiliation(s)
- Madan Kumar Arumugam
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sharanappa Talawar
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Laura Listenberger
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA;
| | - Terrence M. Donohue
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Natalia A. Osna
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kusum K. Kharbanda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Correspondence: ; Tel.: +1-402-995-3752; Fax: +1-402-995-4600
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Forsberg F, Brunet A, Ali TML, Collas P. Interplay of lamin A and lamin B LADs on the radial positioning of chromatin. Nucleus 2020; 10:7-20. [PMID: 30663495 PMCID: PMC6363278 DOI: 10.1080/19491034.2019.1570810] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Immunosuppressive drugs such as cyclosporin A (CsA) can elicit hepatotoxicity by affecting gene expression. Here, we address the link between CsA and large-scale chromatin organization in HepG2 hepatocarcinoma cells. We show the existence of lamina-associated domains (LADs) interacting with lamin A, lamin B, or both. These ‘A-B’, ‘A-only’ and ‘B-only’ LADs display distinct fates after CsA treatment: A-B LADs remain constitutive or lose A, A-only LADs mainly lose A or switch to B, and B-only LADs remain B-only or acquire A. LAD rearrangement is overall uncoupled from changes in gene expression. Three-dimensional (3D) genome modeling predicts changes in radial positioning of LADs as LADs switch identities, which are corroborated by fluorescence in situ hybridization. Our results reveal interplay between A- and B-type lamins on radial locus positioning, suggesting complementary contributions to large-scale genome architecture. The data also unveil a hitherto unsuspected impact of cytotoxic drugs on genome conformation.Abbreviations: ChIP-seq: chromatin immunoprecipitation sequencing; CsA: cyclosporin A; FISH; fluorescence in situ hybridization; ICMT: isoprenylcysteine methyltransferase; LAD: lamina-associated domain; TAD: topologically-associated domain
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Affiliation(s)
- Frida Forsberg
- a Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine , University of Oslo , Oslo , Norway
| | - Annaël Brunet
- a Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine , University of Oslo , Oslo , Norway
| | - Tharvesh M Liyakat Ali
- a Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine , University of Oslo , Oslo , Norway
| | - Philippe Collas
- a Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine , University of Oslo , Oslo , Norway.,b Norwegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine , Oslo University Hospital , Oslo , Norway
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Abstract
At the nuclear periphery, associations of chromatin with the nuclear lamina through lamina-associated domains (LADs) aid functional organization of the genome. We review the organization of LADs and provide evidence of LAD heterogeneity from cell ensemble and single-cell data. LADs are typically repressive environments in the genome; nonetheless, we discuss findings of lamin interactions with regulatory elements of active genes, and the role lamins may play in genome regulation. We address the relationship between LADs and other genome organizers, and the involvement of LADs in laminopathies. The current data lay the basis for future studies on the significance of lamin-chromatin interactions in health and disease.
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Affiliation(s)
- Nolwenn Briand
- Department of Molecular Medicine, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424, Oslo, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway.
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424, Oslo, Norway.
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Vigouroux C, Guénantin AC, Vatier C, Capel E, Le Dour C, Afonso P, Bidault G, Béréziat V, Lascols O, Capeau J, Briand N, Jéru I. Lipodystrophic syndromes due to LMNA mutations: recent developments on biomolecular aspects, pathophysiological hypotheses and therapeutic perspectives. Nucleus 2019; 9:235-248. [PMID: 29578370 PMCID: PMC5973242 DOI: 10.1080/19491034.2018.1456217] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mutations in LMNA, encoding A-type lamins, are responsible for laminopathies including muscular dystrophies, lipodystrophies, and premature ageing syndromes. LMNA mutations have been shown to alter nuclear structure and stiffness, binding to partners at the nuclear envelope or within the nucleoplasm, gene expression and/or prelamin A maturation. LMNA-associated lipodystrophic features, combining generalized or partial fat atrophy and metabolic alterations associated with insulin resistance, could result from altered adipocyte differentiation or from altered fat structure. Recent studies shed some light on how pathogenic A-type lamin variants could trigger lipodystrophy, metabolic complications, and precocious cardiovascular events. Alterations in adipose tissue extracellular matrix and TGF-beta signaling could initiate metabolic inflexibility. Premature senescence of vascular cells could contribute to cardiovascular complications. In affected families, metabolic alterations occur at an earlier age across generations, which could result from epigenetic deregulation induced by LMNA mutations. Novel cellular models recapitulating adipogenic developmental pathways provide scalable tools for disease modeling and therapeutic screening.
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Affiliation(s)
- Corinne Vigouroux
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,b Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires , Paris , France.,c Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Centre National de Référence des Pathologies Rares de l'Insulino-Sécrétion et de l'Insulino-Sensibilité (PRISIS), Service d'Endocrinologie, Diabétologie et Endocrinologie de la Reproduction , Paris , France
| | - Anne-Claire Guénantin
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,d Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus , Hinxton , UK
| | - Camille Vatier
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,c Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Centre National de Référence des Pathologies Rares de l'Insulino-Sécrétion et de l'Insulino-Sensibilité (PRISIS), Service d'Endocrinologie, Diabétologie et Endocrinologie de la Reproduction , Paris , France
| | - Emilie Capel
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Caroline Le Dour
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Pauline Afonso
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Guillaume Bidault
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,e University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital , Cambridge CB2 0QQ , UK
| | - Véronique Béréziat
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Olivier Lascols
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,b Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires , Paris , France
| | - Jacqueline Capeau
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France
| | - Nolwenn Briand
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,f Department of Molecular Medicine , Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo , Blindern , Oslo , Norway
| | - Isabelle Jéru
- a Sorbonne Université, Inserm UMR_S 938, Centre de Recherche Saint-Antoine, Institut Hospitalo-Universitaire de Cardio-métabolisme et Nutrition (ICAN) , Paris , France.,b Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Laboratoire Commun de Biologie et Génétique Moléculaires , Paris , France
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Kreienkamp R, Gonzalo S. Hutchinson-Gilford Progeria Syndrome: Challenges at Bench and Bedside. Subcell Biochem 2019; 91:435-451. [PMID: 30888661 DOI: 10.1007/978-981-13-3681-2_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The structural nuclear proteins known as "lamins" (A-type and B-type) provide a scaffold for the compartmentalization of genome function that is important to maintain genome stability. Mutations in the LMNA gene -encoding for A-type lamins- are associated with over a dozen of degenerative disorders termed laminopathies, which include muscular dystrophies, lipodystrophies, neuropathies, and premature ageing diseases such as Hutchinson Gilford Progeria Syndrome (HGPS). This devastating disease is caused by the expression of a truncated lamin A protein named "progerin". To date, there is no effective treatment for HGPS patients, who die in their teens from cardiovascular disease. At a cellular level, progerin expression impacts nuclear architecture, chromatin organization, response to mechanical stress, and DNA transactions such as transcription, replication and repair. However, the current view is that key mechanisms behind progerin toxicity still remain to be discovered. Here, we discuss new findings about pathological mechanisms in HGPS, especially the contribution of replication stress to cellular decline, and therapeutic strategies to ameliorate progerin toxicity. In particular, we present evidence for retinoids and calcitriol (hormonal vitamin D metabolite) being among the most potent compounds to ameliorate HGPS cellular phenotypes in vitro, providing the rationale for testing these compounds in preclinical models of the disease in the near term, and in patients in the future.
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Affiliation(s)
- Ray Kreienkamp
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Doisy Research Center, St Louis University School of Medicine, St. Louis, MO, USA
| | - Susana Gonzalo
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Doisy Research Center, St Louis University School of Medicine, St. Louis, MO, USA.
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13
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Ho R, Hegele RA. Complex effects of laminopathy mutations on nuclear structure and function. Clin Genet 2018; 95:199-209. [DOI: 10.1111/cge.13455] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Rosettia Ho
- Departments of Biochemistry and Medicine, and Robarts Research Institute; Schulich School of Medicine and Dentistry, Western University; London Ontario Canada
| | - Robert A. Hegele
- Departments of Biochemistry and Medicine, and Robarts Research Institute; Schulich School of Medicine and Dentistry, Western University; London Ontario Canada
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14
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Khanna R, Krishnamoorthy V, Parnaik VK. E3 ubiquitin ligase RNF123 targets lamin B1 and lamin-binding proteins. FEBS J 2018; 285:2243-2262. [PMID: 29676528 DOI: 10.1111/febs.14477] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 03/26/2018] [Accepted: 04/13/2018] [Indexed: 12/27/2022]
Abstract
Lamins are key nuclear proteins which are important for maintaining nuclear structure and function. Mutations in lamins cause a spectrum of genetic diseases termed as laminopathies. RING finger containing E3 ubiquitin ligase, RNF123, is transcriptionally upregulated in cells expressing rod domain lamin A mutations. However, the functional relevance of RNF123 in laminopathic cells is not clear. Using a mass spectrometry-based approach, we identified lamins and lamin-binding proteins retinoblastoma protein (pRb), lamina-associated polypeptide 2α (LAP2α), and emerin as RNF123-interacting proteins. We determined that RNF123 mediated the ubiquitination of these proteins and caused the proteasomal degradation of pRb, LAP2α, and lamin B1. Furthermore, these proteins were also targeted for proteasomal degradation in cells expressing lamin A rod domain mutants G232E, Q294P, and R386K. Overexpression of RNF123 resulted in delayed transit through the S-phase which was alleviated by coexpression of pRb or LAP2α. Our findings imply that RNF123-mediated ubiquitination of lamin-binding proteins may contribute to disease-causing mechanisms in laminopathies by depletion of key nuclear proteins and defects in cell cycle kinetics.
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Affiliation(s)
- Richa Khanna
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Veena K Parnaik
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
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15
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Davies SJ, Ryan J, O'Connor PBF, Kenny E, Morris D, Baranov PV, O'Connor R, McCarthy TV. Itm2a silencing rescues lamin A mediated inhibition of 3T3-L1 adipocyte differentiation. Adipocyte 2017; 6:259-276. [PMID: 28872940 DOI: 10.1080/21623945.2017.1362510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Dysregulation of adipose tissue metabolism is associated with multiple metabolic disorders. One such disease, known as Dunnigan-type familial partial lipodystrophy (FPLD2) is characterized by defective fat metabolism and storage. FPLD2 is caused by a specific subset of mutations in the LMNA gene. The mechanisms by which LMNA mutations lead to the adipose specific FPLD2 phenotype have yet to be determined in detail. We used RNA-Seq analysis to assess the effects of wild-type (WT) and mutant (R482W) lamin A on the expression profile of differentiating 3T3-L1 mouse preadipocytes and identified Itm2a as a gene that was upregulated at 36 h post differentiation induction in these cells. In this study we identify Itm2a as a novel modulator of adipogenesis and show that endogenous Itm2a expression is transiently downregulated during induction of 3T3-L1 differentiation. Itm2a overexpression was seen to moderately inhibit differentiation of 3T3-L1 preadipocytes while shRNA mediated knockdown of Itm2a significantly enhanced 3T3-L1 differentiation. Investigation of PPARγ levels indicate that this enhanced adipogenesis is mediated through the stabilization of the PPARγ protein at specific time points during differentiation. Finally, we demonstrate that Itm2a knockdown is sufficient to rescue the inhibitory effects of lamin A WT and R482W mutant overexpression on 3T3-L1 differentiation. This suggests that targeting of Itm2a or its related pathways, including autophagy, may have potential as a therapy for FPLD2.
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Affiliation(s)
- Stephanie J. Davies
- School of Biochemistry and Cell Biology, University College Cork, Co. Cork, Ireland
| | - James Ryan
- Mater Private Hospital, Citygate, Mahon, Cork, Ireland
| | | | - Elaine Kenny
- Neuropsychiatric Genetics Research Group, Department of Psychiatry and Institute of Molecular Medicine, Trinity College Dublin, Dublin, Ireland
| | - Derek Morris
- Department of Biochemistry, National University of Ireland Galway, Galway, Ireland
| | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, Co. Cork, Ireland
| | - Rosemary O'Connor
- School of Biochemistry and Cell Biology, University College Cork, Co. Cork, Ireland
| | - Tommie V. McCarthy
- School of Biochemistry and Cell Biology, University College Cork, Co. Cork, Ireland
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16
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Oldenburg A, Briand N, Sørensen AL, Cahyani I, Shah A, Moskaug JØ, Collas P. A lipodystrophy-causing lamin A mutant alters conformation and epigenetic regulation of the anti-adipogenic MIR335 locus. J Cell Biol 2017; 216:2731-2743. [PMID: 28751304 PMCID: PMC5584164 DOI: 10.1083/jcb.201701043] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/04/2017] [Accepted: 06/20/2017] [Indexed: 12/30/2022] Open
Abstract
Mutations in the Lamin A/C (LMNA) gene-encoding nuclear LMNA cause laminopathies, which include partial lipodystrophies associated with metabolic syndromes. The lipodystrophy-associated LMNA p.R482W mutation is known to impair adipogenic differentiation, but the mechanisms involved are unclear. We show in this study that the lamin A p.R482W hot spot mutation prevents adipogenic gene expression by epigenetically deregulating long-range enhancers of the anti-adipogenic MIR335 microRNA gene in human adipocyte progenitor cells. The R482W mutation results in a loss of function of differentiation-dependent lamin A binding to the MIR335 locus. This impairs H3K27 methylation and instead favors H3K27 acetylation on MIR335 enhancers. The lamin A mutation further promotes spatial clustering of MIR335 enhancer and promoter elements along with overexpression of the MIR355 gene after adipogenic induction. Our results link a laminopathy-causing lamin A mutation to an unsuspected deregulation of chromatin states and spatial conformation of an miRNA locus critical for adipose progenitor cell fate.
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Affiliation(s)
- Anja Oldenburg
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Nolwenn Briand
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anita L Sørensen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Inswasti Cahyani
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Akshay Shah
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Jan Øivind Moskaug
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway.,Norwegian Center for Stem Cell Research, Department of Immunology, Oslo University Hospital, Oslo, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway .,Norwegian Center for Stem Cell Research, Department of Immunology, Oslo University Hospital, Oslo, Norway
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17
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Paulsen J, Sekelja M, Oldenburg AR, Barateau A, Briand N, Delbarre E, Shah A, Sørensen AL, Vigouroux C, Buendia B, Collas P. Chrom3D: three-dimensional genome modeling from Hi-C and nuclear lamin-genome contacts. Genome Biol 2017; 18:21. [PMID: 28137286 PMCID: PMC5278575 DOI: 10.1186/s13059-016-1146-2] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 12/23/2016] [Indexed: 01/09/2023] Open
Abstract
Current three-dimensional (3D) genome modeling platforms are limited by their inability to account for radial placement of loci in the nucleus. We present Chrom3D, a user-friendly whole-genome 3D computational modeling framework that simulates positions of topologically-associated domains (TADs) relative to each other and to the nuclear periphery. Chrom3D integrates chromosome conformation capture (Hi-C) and lamin-associated domain (LAD) datasets to generate structure ensembles that recapitulate radial distributions of TADs detected in single cells. Chrom3D reveals unexpected spatial features of LAD regulation in cells from patients with a laminopathy-causing lamin mutation. Chrom3D is freely available on github.
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Affiliation(s)
- Jonas Paulsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Monika Sekelja
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anja R Oldenburg
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | | | - Nolwenn Briand
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Erwan Delbarre
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Akshay Shah
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anita L Sørensen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Corinne Vigouroux
- INSERM, UMR S938, Centre de Recherches Saint-Antoine, Paris, France.,UPMC Université Paris 6 UMR S938, Paris, France.,ICAN, Paris, France.,AP-HP Hôpital Tenon, Paris, France
| | | | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway. .,Norwegian Center for Stem Cell Research, Oslo University Hospital, Oslo, Norway.
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18
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A Novel Lamin A Mutant Responsible for Congenital Muscular Dystrophy Causes Distinct Abnormalities of the Cell Nucleus. PLoS One 2017; 12:e0169189. [PMID: 28125586 PMCID: PMC5268432 DOI: 10.1371/journal.pone.0169189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 12/13/2016] [Indexed: 11/26/2022] Open
Abstract
A-type lamins, the intermediate filament proteins participating in nuclear structure and function, are encoded by LMNA. LMNA mutations can lead to laminopathies such as lipodystrophies, premature aging syndromes (progeria) and muscular dystrophies. Here, we identified a novel heterozygous LMNA p.R388P de novo mutation in a patient with a non-previously described severe phenotype comprising congenital muscular dystrophy (L-CMD) and lipodystrophy. In culture, the patient’s skin fibroblasts entered prematurely into senescence, and some nuclei showed a lamina honeycomb pattern. C2C12 myoblasts were transfected with a construct carrying the patient’s mutation; R388P-lamin A (LA) predominantly accumulated within the nucleoplasm and was depleted at the nuclear periphery, altering the anchorage of the inner nuclear membrane protein emerin and the nucleoplasmic protein LAP2-alpha. The mutant LA triggered a frequent and severe nuclear dysmorphy that occurred independently of prelamin A processing, as well as increased histone H3K9 acetylation. Nuclear dysmorphy was not significantly improved when transfected cells were treated with drugs disrupting microtubules or actin filaments or modifying the global histone acetylation pattern. Therefore, releasing any force exerted at the nuclear envelope by the cytoskeleton or chromatin did not rescue nuclear shape, in contrast to what was previously shown in Hutchinson-Gilford progeria due to other LMNA mutations. Our results point to the specific cytotoxic effect of the R388P-lamin A mutant, which is clinically related to a rare and severe multisystemic laminopathy phenotype.
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19
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Gonzalo S, Kreienkamp R, Askjaer P. Hutchinson-Gilford Progeria Syndrome: A premature aging disease caused by LMNA gene mutations. Ageing Res Rev 2017; 33:18-29. [PMID: 27374873 DOI: 10.1016/j.arr.2016.06.007] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/25/2016] [Accepted: 06/28/2016] [Indexed: 01/08/2023]
Abstract
Products of the LMNA gene, primarily lamin A and C, are key components of the nuclear lamina, a proteinaceous meshwork that underlies the inner nuclear membrane and is essential for proper nuclear architecture. Alterations in lamin A and C that disrupt the integrity of the nuclear lamina affect a whole repertoire of nuclear functions, causing cellular decline. In humans, hundreds of mutations in the LMNA gene have been identified and correlated with over a dozen degenerative disorders, referred to as laminopathies. These diseases include neuropathies, muscular dystrophies, lipodystrophies, and premature aging diseases. This review focuses on one of the most severe laminopathies, Hutchinson-Gilford Progeria Syndrome (HGPS), which is caused by aberrant splicing of the LMNA gene and expression of a mutant product called progerin. Here, we discuss current views about the molecular mechanisms that contribute to the pathophysiology of this devastating disease, as well as the strategies being tested in vitro and in vivo to counteract progerin toxicity. In particular, progerin accumulation elicits nuclear morphological abnormalities, misregulated gene expression, defects in DNA repair, telomere shortening, and genomic instability, all of which limit cellular proliferative capacity. In patients harboring this mutation, a severe premature aging disease develops during childhood. Interestingly, progerin is also produced in senescent cells and cells from old individuals, suggesting that progerin accumulation might be a factor in physiological aging. Deciphering the molecular mechanisms whereby progerin expression leads to HGPS is an emergent area of research, which could bring us closer to understanding the pathology of aging.
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Affiliation(s)
- Susana Gonzalo
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA.
| | - Ray Kreienkamp
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/Junta de Andalucia/Universidad Pablo de Olavide, Carretera de Utrera, Km 1, 41013 Seville, Spain
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20
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Padiath QS. Lamin B1 mediated demyelination: Linking Lamins, Lipids and Leukodystrophies. Nucleus 2016; 7:547-553. [PMID: 27854160 PMCID: PMC5214339 DOI: 10.1080/19491034.2016.1260799] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/01/2016] [Accepted: 11/10/2016] [Indexed: 01/08/2023] Open
Abstract
Autosomal Dominant Leukodystrophy (ADLD), a fatal adult onset demyelinating disorder, is the only human disease that has been linked to mutations of the nuclear lamina protein, lamin B1, and is primarily caused by duplications of the LMNB1 gene. Why CNS myelin is specifically targeted and the mechanisms underlying ADLD are unclear. Recent work from our group has demonstrated that over expression of lamin B1 in oligodendrocytes, the myelin producing cells in the CNS, resulted in age dependent epigenetic modifications, transcriptional down-regulation of lipogenic gene expression and significant reductions of myelin-enriched lipids. Given the high lipid content of meylin, we hypothesize that lipid loss is one of the primary drivers of the demyelination phenotype. These results can, at least partially, explain the age dependence and cell type specificity in ADLD and are discussed in the context of the existing literature, in an attempt to delineate potential pathways underlying the disease phenotype.
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Affiliation(s)
- Quasar S. Padiath
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
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21
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Wu CY, Wu YY, Liu CD, Wang YX, Na W, Wang N, Li H. Comparative proteome analysis of abdominal adipose tissues between fat and lean broilers. Proteome Sci 2016; 14:9. [PMID: 27594807 PMCID: PMC5009711 DOI: 10.1186/s12953-016-0100-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 08/16/2016] [Indexed: 02/04/2023] Open
Abstract
Background The molecular mechanism underlying broiler fat deposition is still poorly understood. Method Currently, we used two-dimensional gel electrophoresis (2DE) to identify differentially expressed proteins in abdominal adipose tissues of birds at 4 week of age derived from Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF). Results Thirteen differentially expressed protein spots were screened out and identified by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The protein spots were matched to thirteen proteins by searching against the NCBInr database. These identified proteins were apolipoprotein A-I (Apo A-I), cytokeratin otokeratin, ATP synthase subunit alpha, peptidyl-prolyl cis-trans isomerase FKBP4 (PPIase FKBP4), aspartate aminotransferase, carbonic anhydrase II (CA-II), prostaglandin-H2 D-isomerase precursor, fibrinogen alpha chain, lamin-A (LMNA), superoxide dismutase [Mn] (MnSOD), heat shock protein beta-1 (HSPβ1) and two predicted proteins. These differentially expressed proteins are involved mainly in lipid metabolism, amino acid metabolism, signal transduction, energy conversion, antioxidant, and cytoskeleton. Differential expression of Apo A-I, PPIase FKBP4, and cytokeratin otokeratin proteins were further confirmed by Western blot analysis. Quantitative real-time RT-PCR analyses showed that, of these 13 differentially expressed proteins, only PPIase FKBP4 and cytokeratin otokeratin were differentially expressed at mRNA level between the two lines. Conclusions Our results have provided further information for understanding the basic genetics control of growth and development of broiler adipose tissue.
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Affiliation(s)
- Chun-Yan Wu
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China
| | - Yuan-Yuan Wu
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China.,Weifang Academy of Agricultural Sciences, Weifang, 261071 Shandong China
| | - Chun-Dong Liu
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China
| | - Yu-Xiang Wang
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China
| | - Wei Na
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China
| | - Ning Wang
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China
| | - Hui Li
- Key Laboratory of Chicken Genetics and Breeding of Agriculture Ministry, Key Laboratory of Animal Genetics, Breeding and Reproduction of Education Department of Heilongjiang Province, College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030 Heilongjiang China
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22
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Barateau A, Buendia B. In Situ Detection of Interactions Between Nuclear Envelope Proteins and Partners. Methods Mol Biol 2016; 1411:147-58. [PMID: 27147040 DOI: 10.1007/978-1-4939-3530-7_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Proximity ligation assay (PLA) appears as a quick and easy technique to visualize within fixed cells the occurrence and in situ distribution of protein complexes. PLA has been validated to detect protein-protein interactions within the nuclear compartment. Here, we describe a protocol which allows the detection of interactions between A-type nuclear lamins and either LEM-domain proteins (such as emerin, integrated within the inner nuclear membrane, and LAP2α which accumulates within the nucleoplasm) or gene regulatory factors (e.g., the transcription factor SREBP1). The distinct amounts and patterns of PLA signals obtained for various complexes highlight the pertinence of using PLA to reveal in situ where and to which extent nuclear envelope proteins bind specific partners.
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Affiliation(s)
- Alice Barateau
- Unit of Functional and Adaptive Biology (BFA) CNRS UMR 8251, Université Paris Diderot, Sorbonne Paris Cité, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13, 75205, France
| | - Brigitte Buendia
- Unit of Functional and Adaptive Biology (BFA) CNRS UMR 8251, Université Paris Diderot, Sorbonne Paris Cité, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13, 75205, France.
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23
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Herrada I, Samson C, Velours C, Renault L, Östlund C, Chervy P, Puchkov D, Worman HJ, Buendia B, Zinn-Justin S. Muscular Dystrophy Mutations Impair the Nuclear Envelope Emerin Self-assembly Properties. ACS Chem Biol 2015; 10:2733-42. [PMID: 26415001 DOI: 10.1021/acschembio.5b00648] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
More than 100 genetic mutations causing X-linked Emery-Dreifuss muscular dystrophy have been identified in the gene encoding the integral inner nuclear membrane protein emerin. Most mutations are nonsense or frameshift mutations that lead to the absence of emerin in cells. Only very few cases are due to missense or short in-frame deletions. Molecular mechanisms explaining the corresponding emerin variants' loss of function are particularly difficult to identify because of the mostly intrinsically disordered state of the emerin nucleoplasmic region. We now demonstrate that this EmN region can be produced as a disordered monomer, as revealed by nuclear magnetic resonance, but rapidly self-assembles in vitro. Increases in concentration and temperature favor the formation of long curvilinear filaments with diameters of approximately 10 nm, as observed by electron microscopy. Assembly of these filaments can be followed by fluorescence through Thioflavin-T binding and by Fourier-transform Infrared spectrometry through formation of β-structures. Analysis of the assembly properties of five EmN variants reveals that del95-99 and Q133H impact filament assembly capacities. In cells, these variants are located at the nuclear envelope, but the corresponding quantities of emerin-emerin and emerin-lamin proximities are decreased compared to wild-type protein. Furthermore, variant P183H favors EmN aggregation in vitro, and variant P183T provokes emerin accumulation in cytoplasmic foci in cells. Substitution of residue Pro183 might systematically favor oligomerization, leading to emerin aggregation and mislocalization in cells. Our results suggest that emerin self-assembly is necessary for its proper function and that a loss of either the protein itself or its ability to self-assemble causes muscular dystrophy.
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Affiliation(s)
- Isaline Herrada
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
| | - Camille Samson
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
| | - Christophe Velours
- Laboratoire
d’Enzymologie et Biochimie Structurales, Institute for Integrative Biology of the Cell (I2BC), CNRS Bât.34, 1 avenue de
la terrasse, 91190 Gif-sur-Yvette, France
| | - Louis Renault
- Laboratoire
d’Enzymologie et Biochimie Structurales, Institute for Integrative Biology of the Cell (I2BC), CNRS Bât.34, 1 avenue de
la terrasse, 91190 Gif-sur-Yvette, France
| | - Cecilia Östlund
- Department
of Medicine and Department of Pathology and Cell Biology, College
of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, United States
| | - Pierre Chervy
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
| | - Dmytro Puchkov
- Department
of Molecular Pharmacology and Cell Biology, Leibniz-Institut für Molecular Pharmakologie (FMP), 13125 Berlin, Germany
| | - Howard J Worman
- Department
of Medicine and Department of Pathology and Cell Biology, College
of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, United States
| | - Brigitte Buendia
- Laboratoire
de Physiologie du Muscle Strié, Université Paris Diderot-Paris 7, CNRS, UMR 8251, Institut de Biologie
Fonctionnelle et Adaptative, 4 rue
M.A. Lagroua Weill Halle, 75205 Paris Cedex 13, France
| | - Sophie Zinn-Justin
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
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24
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Lund EG, Duband-Goulet I, Oldenburg A, Buendia B, Collas P. Distinct features of lamin A-interacting chromatin domains mapped by ChIP-sequencing from sonicated or micrococcal nuclease-digested chromatin. Nucleus 2015; 6:30-9. [PMID: 25602132 DOI: 10.4161/19491034.2014.990855] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The nuclear lamina has been shown to interact with the genome through lamina-associated domains (LADs). LADs have been identified by DamID, a proximity labeling assay, and more recently by chromatin immunoprecipitation-sequencing (ChIP-seq) of A- and B-type lamins. LADs form megabase-size domains at the nuclear periphery, they are gene-poor and mostly heterochromatic. Here, we show that the mode of chromatin fragmentation for ChIP, namely bath sonication or digestion with micrococcal nuclease (MNase), leads to the discovery of common but also distinct sets of lamin-interacting domains, or LiDs. Using ChIP-seq, we show the existence of lamin A/C (LMNA) LiDs with distinct gene contents, histone composition enrichment and relationships to lamin B1-interacting domains. The extent of genome coverage of lamin A/C (LMNA) LiDs in sonicated or MNase-digested chromatin is similar (∼730 megabases); however over half of these domains are uniquely detected in sonicated or MNase-digested chromatin. Sonication-specific LMNA LiDs are gene-poor and devoid of a broad panel of histone modifications, while MNase-specific LMNA LiDs are of higher gene density and are enriched in H3K9me3, H3K27me3 and in histone variant H2A.Z. LMNB1 LiDs are gene-poor and show no or little enrichment in these marks. Comparison of published LMNB1 DamID LADs with LMNB1 and LMNA LiDs identified here by ChIP-seq further shows that LMNA can associate with 'open' chromatin domains displaying euchromatin characteristics, and which are not associated with LMNB1. The differential genomic and epigenetic properties of lamin-interacting domains reflect the existence of distinct LiD populations identifiable in different chromatin contexts, including nuclease-accessible regions presumably localized in the nuclear interior.
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Affiliation(s)
- Eivind G Lund
- a Department of Molecular Medicine, Institute of Basic Medical Sciences ; University of Oslo, and Norwegian Center for Stem Cell Research , Oslo , Norway
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Rolyan H, Tyurina YY, Hernandez M, Amoscato AA, Sparvero LJ, Nmezi BC, Lu Y, Estécio MRH, Lin K, Chen J, He RR, Gong P, Rigatti LH, Dupree J, Bayır H, Kagan VE, Casaccia P, Padiath QS. Defects of Lipid Synthesis Are Linked to the Age-Dependent Demyelination Caused by Lamin B1 Overexpression. J Neurosci 2015; 35:12002-17. [PMID: 26311780 PMCID: PMC4549407 DOI: 10.1523/jneurosci.1668-15.2015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 06/24/2015] [Accepted: 07/23/2015] [Indexed: 11/21/2022] Open
Abstract
Lamin B1 is a component of the nuclear lamina and plays a critical role in maintaining nuclear architecture, regulating gene expression and modulating chromatin positioning. We have previously shown that LMNB1 gene duplications cause autosomal dominant leukodystrophy (ADLD), a fatal adult onset demyelinating disease. The mechanisms by which increased LMNB1 levels cause ADLD are unclear. To address this, we used a transgenic mouse model where Lamin B1 overexpression is targeted to oligodendrocytes. These mice showed severe vacuolar degeneration of the spinal cord white matter together with marked astrogliosis, microglial infiltration, and secondary axonal damage. Oligodendrocytes in the transgenic mice revealed alterations in histone modifications favoring a transcriptionally repressed state. Chromatin changes were accompanied by reduced expression of genes involved in lipid synthesis pathways, many of which are known to play important roles in myelin regulation and are preferentially expressed in oligodendrocytes. Decreased lipogenic gene expression resulted in a significant reduction in multiple classes of lipids involved in myelin formation. Many of these gene expression changes and lipid alterations were observed even before the onset of the phenotype, suggesting a causal role. Our findings establish, for the first time, a link between LMNB1 and lipid synthesis in oligodendrocytes, and provide a mechanistic framework to explain the age dependence and white matter involvement of the disease phenotype. These results have implications for disease pathogenesis and may also shed light on the regulation of lipid synthesis pathways in myelin maintenance and turnover. SIGNIFICANCE STATEMENT Autosomal dominant leukodystrophy (ADLD) is fatal neurological disorder caused by increased levels of the nuclear protein, Lamin B1. The disease is characterized by an age-dependent loss of myelin, the fatty sheath that covers nerve fibers. We have studied a mouse model where Lamin B1 level are increased in oligodendrocytes, the cell type that produces myelin in the CNS. We demonstrate that destruction of myelin in the spinal cord is responsible for the degenerative phenotype in our mouse model. We show that this degeneration is mediated by reduced expression of lipid synthesis genes and the subsequent reduction in myelin enriched lipids. These findings provide a mechanistic framework to explain the age dependence and tissue specificity of the ADLD disease phenotype.
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Affiliation(s)
- Harshvardhan Rolyan
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15216
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Marylens Hernandez
- Friedman Brain Institute Center for Neural Repair, Department of Neuroscience, and Graduate School of Biological Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Andrew A Amoscato
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Louis J Sparvero
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Bruce C Nmezi
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15216
| | - Yue Lu
- Department of Epigenetics and Molecular Carcinogenesis, and Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Marcos R H Estécio
- Department of Epigenetics and Molecular Carcinogenesis, and Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Kevin Lin
- Department of Epigenetics and Molecular Carcinogenesis, and Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Junda Chen
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15216
| | - Rong-Rong He
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Pin Gong
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Lora H Rigatti
- Division of Laboratory Animal Resources, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Jeffrey Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23298, and
| | - Hülya Bayır
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, Safar Center for Resuscitation Research and Departments of Critical Care Medicine
| | - Valerian E Kagan
- Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, Pharmacology and Chemical Biology, Chemistry, and Radiation Oncology, University of Pittsburgh, Pittsburgh, Pennsylvania 15219
| | - Patrizia Casaccia
- Graduate School of Biological Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Quasar S Padiath
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15216,
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Gay S, Foiani M. Nuclear envelope and chromatin, lock and key of genome integrity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:267-330. [PMID: 26008788 DOI: 10.1016/bs.ircmb.2015.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
More than as an inert separation between the inside and outside of the nucleus, the nuclear envelope (NE) constitutes an active toll, which controls the import and export of molecules, and also a hub for a diversity of genomic processes, such as transcription, DNA repair, and chromatin dynamics. Proteins localized at the inner surface of the NE (such as lamins, nuclear pore proteins, lamin-associated proteins) interact with chromatin in a dynamic manner, contributing to the establishment of topological domains. In this review, we address the complex interplay between chromatin and NE. We discuss the divergence of this cross talk during evolution and comment both on the current established models and the most recent findings. In particular, we focus our attention on how the NE cooperates with chromatin in protecting the genome integrity.
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Affiliation(s)
- Sophie Gay
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Marco Foiani
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy; Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milan, Italy
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Gruenbaum Y, Foisner R. Lamins: nuclear intermediate filament proteins with fundamental functions in nuclear mechanics and genome regulation. Annu Rev Biochem 2015; 84:131-64. [PMID: 25747401 DOI: 10.1146/annurev-biochem-060614-034115] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lamins are intermediate filament proteins that form a scaffold, termed nuclear lamina, at the nuclear periphery. A small fraction of lamins also localize throughout the nucleoplasm. Lamins bind to a growing number of nuclear protein complexes and are implicated in both nuclear and cytoskeletal organization, mechanical stability, chromatin organization, gene regulation, genome stability, differentiation, and tissue-specific functions. The lamin-based complexes and their specific functions also provide insights into possible disease mechanisms for human laminopathies, ranging from muscular dystrophy to accelerated aging, as observed in Hutchinson-Gilford progeria and atypical Werner syndromes.
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Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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Gross DA, Silver DL. Cytosolic lipid droplets: from mechanisms of fat storage to disease. Crit Rev Biochem Mol Biol 2015; 49:304-26. [PMID: 25039762 DOI: 10.3109/10409238.2014.931337] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The lipid droplet (LD) is a phylogenetically conserved organelle. In eukaryotes, it is born from the endoplasmic reticulum, but unlike its parent organelle, LDs are the only known cytosolic organelles that are micellar in structure. LDs are implicated in numerous physiological and pathophysiological functions. Many aspects of the LD has captured the attention of diverse scientists alike and has recently led to an explosion in information on the LD biogenesis, expansion and fusion, identification of LD proteomes and diseases associated with LD biology. This review will provide a brief history of this fascinating organelle and provide some contemporary views of unanswered questions in LD biogenesis.
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Affiliation(s)
- David A Gross
- Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School Singapore , Singapore , and
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Vadrot N, Duband-Goulet I, Cabet E, Attanda W, Barateau A, Vicart P, Gerbal F, Briand N, Vigouroux C, Oldenburg AR, Lund EG, Collas P, Buendia B. The p.R482W substitution in A-type lamins deregulates SREBP1 activity in Dunnigan-type familial partial lipodystrophy. Hum Mol Genet 2014; 24:2096-109. [PMID: 25524705 DOI: 10.1093/hmg/ddu728] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Nuclear lamins are involved in many cellular functions due to their ability to bind numerous partners including chromatin and transcription factors, and affect their properties. Dunnigan type familial partial lipodystrophy (FPLD2; OMIM#151660) is caused in most cases by the A-type lamin R482W mutation. We report here that the R482W mutation affects the regulatory activity of sterol response element binding protein 1 (SREBP1), a transcription factor that regulates hundreds of genes involved in lipid metabolism and adipocyte differentiation. Using in situ proximity ligation assays (PLA), reporter assays and biochemical and transcriptomic approaches, we show that interactions of SREBP1 with lamin A and lamin C occur at the nuclear periphery and in the nucleoplasm. These interactions involve the Ig-fold of A-type lamins and are favored upon SREBP1 binding to its DNA target sequences. We show that SREBP1, LMNA and sterol response DNA elements form ternary complexes in vitro. In addition, overexpression of A-type lamins reduces transcriptional activity of SREBP1. In contrast, both overexpression of LMNA R482W in primary human preadipocytes and endogenous expression of A-type lamins R482W in FPLD2 patient fibroblasts, reduce A-type lamins-SREBP1 in situ interactions and upregulate a large number of SREBP1 target genes. As this LMNA mutant was previously shown to inhibit adipogenic differentiation, we propose that deregulation of SREBP1 by mutated A-type lamins constitutes one underlying mechanism of the physiopathology of FPLD2. Our data suggest that SREBP1 targeting molecules could be considered in a therapeutic context.
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Affiliation(s)
- Nathalie Vadrot
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Isabelle Duband-Goulet
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Eva Cabet
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Wikayatou Attanda
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Alice Barateau
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Patrick Vicart
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France
| | - Fabien Gerbal
- Université Paris Diderot, Matière et Systèmes Complexes, CNRS UMR 7057, 10 rue Alice Domon et Leonie Duquet, Paris Cedex 13 75205, France, Physics Department, Université Pierre et Marie Curie, Paris UFR925, France
| | - Nolwenn Briand
- Faculté de Médecine Pierre et Marie Curie, Inserm, UMR S938, Centre de Recherche Saint-Antoine, 27 rue Chaligny, Paris F-75012, France, Sorbonne Universités, UPMC Univ Paris 6, UMR S938, Paris F-75005, France, ICAN, Institute of Cardiometabolism and Nutrition, Paris F-75013, France
| | - Corinne Vigouroux
- Faculté de Médecine Pierre et Marie Curie, Inserm, UMR S938, Centre de Recherche Saint-Antoine, 27 rue Chaligny, Paris F-75012, France, Sorbonne Universités, UPMC Univ Paris 6, UMR S938, Paris F-75005, France, ICAN, Institute of Cardiometabolism and Nutrition, Paris F-75013, France, Laboratoire Commun de Biologie et Génétique Moléculaires, AP-HP, Hôpital Saint-Antoine, Paris F-75012, France and
| | - Anja R Oldenburg
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, Oslo 0317, Norway
| | - Eivind G Lund
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, Oslo 0317, Norway
| | - Philippe Collas
- Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, Oslo 0317, Norway
| | - Brigitte Buendia
- Unit of Functional and Adaptive Biology (BFA), Université Paris Diderot-Paris 7 Affiliated with CNRS, 4 rue Marie-Andrée Lagroua Weill-Halle, Paris Cedex 13 75205, France,
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Amendola M, van Steensel B. Mechanisms and dynamics of nuclear lamina–genome interactions. Curr Opin Cell Biol 2014; 28:61-8. [DOI: 10.1016/j.ceb.2014.03.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/06/2014] [Accepted: 03/08/2014] [Indexed: 12/21/2022]
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Nuclear envelope-related lipodystrophies. Semin Cell Dev Biol 2014; 29:148-57. [DOI: 10.1016/j.semcdb.2013.12.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/06/2013] [Accepted: 12/20/2013] [Indexed: 12/12/2022]
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Oldenburg AR, Delbarre E, Thiede B, Vigouroux C, Collas P. Deregulation of Fragile X-related protein 1 by the lipodystrophic lamin A p.R482W mutation elicits a myogenic gene expression program in preadipocytes. Hum Mol Genet 2013; 23:1151-62. [PMID: 24108105 DOI: 10.1093/hmg/ddt509] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The nuclear lamina is implicated in the regulation of various nuclear functions. Several laminopathy-causing mutations in the LMNA gene, notably the p.R482W substitution linked to familial partial lipodystrophy type 2 (FPLD2), are clustered in the immunoglobulin fold of lamin A. We report a functional association between lamin A and fragile X-related protein 1 (FXR1P), a protein of the fragile X-related family involved in fragile X syndrome. Searching for proteins differentially interacting with the immunoglobulin fold of wild-type and R482W mutant lamin A, we identify FXR1P as a novel component of the lamin A protein network. The p.R482W mutation abrogates interaction of FXR1P with lamin A. Fibroblasts from FPLD2 patients display elevated levels of FXR1P and delocalized FXR1P. In human adipocyte progenitors, deregulation of lamin A expression leads to FXR1P up-regulation, impairment of adipogenic differentiation and induction of myogenin expression. FXR1P overexpression also stimulates a myogenic gene expression program in these cells. Our results demonstrate a cross-talk between proteins hitherto implicated in two distinct mesodermal pathologies. We propose a model where the FPLD2 lamin A p.R482W mutation elicits, through up-regulation of FXR1P, a remodeling of an adipogenic differentiation program into a myogenic program.
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Affiliation(s)
- Anja R Oldenburg
- Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences and Norwegian Center for Stem Cell Research, Faculty of Medicine, University of Oslo, PO Box 1112, Blindern, Oslo 0317, Norway
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N-acetyl-L-cysteine prevents stress-induced desmin aggregation in cellular models of desminopathy. PLoS One 2013; 8:e76361. [PMID: 24098483 PMCID: PMC3788106 DOI: 10.1371/journal.pone.0076361] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 08/24/2013] [Indexed: 11/19/2022] Open
Abstract
Mutations within the human desmin gene are responsible for a subcategory of myofibrillar myopathies called desminopathies. However, a single inherited mutation can produce different phenotypes within a family, suggesting that environmental factors influence disease states. Although several mouse models have been used to investigate organ-specific desminopathies, a more general mechanistic perspective is required to advance our knowledge toward patient treatment. To improve our understanding of disease pathology, we have developed cellular models to observe desmin behaviour in early stages of disease pathology, e.g., upon formation of cytoplasmic desmin aggregates, within an isogenic background. We cloned the wildtype and three mutant desmin cDNAs using a Tet-On Advanced® expression system in C2C12 cells. Mutations were selected based on positioning within desmin and capacity to form aggregates in transient experiments, as follows: DesS46Y (head domain; low aggregation), DesD399Y (central rod domain; high aggregation), and DesS460I (tail domain; moderate aggregation). Introduction of these proteins into a C2C12 background permitted us to compare between desmin variants as well as to determine the role of external stress on aggregation. Three different types of stress, likely encountered during muscle activity, were introduced to the cell models-thermal (heat shock), redox-associated (H2O2 and cadmium chloride), and mechanical (stretching) stresses-after which aggregation was measured. Cells containing variant DesD399Y were more sensitive to stress, leading to marked cytoplasmic perinuclear aggregations. We then evaluated the capacity of biochemical compounds to prevent this aggregation, applying dexamethasone (an inducer of heat shock proteins), fisetin or N-acetyl-L-cysteine (antioxidants) before stress induction. Interestingly, N-acetyl-L-cysteine pre-treatment prevented DesD399Y aggregation during most stress. N-acetyl-L-cysteine has recently been described as a promising antioxidant in myopathies linked to selenoprotein N or ryanodin receptor defects. Our findings indicate that this drug warrants further study in animal models to speed its potential development as a therapy for DesD399Y-linked desminopathies.
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Prokocimer M, Barkan R, Gruenbaum Y. Hutchinson-Gilford progeria syndrome through the lens of transcription. Aging Cell 2013; 12:533-43. [PMID: 23496208 DOI: 10.1111/acel.12070] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2013] [Indexed: 12/14/2022] Open
Abstract
Lamins are nuclear intermediate filaments. In addition to their structural roles, they are implicated in basic nuclear functions such as chromatin organization, DNA replication, transcription, DNA repair, and cell-cycle progression. Mutations in human LMNA gene cause several diseases termed laminopathies. One of the laminopathic diseases is Hutchinson-Gilford progeria syndrome (HGPS), which is caused by a spontaneous mutation and characterized by premature aging. HGPS phenotypes share certain similarities with several apparently comparable medical conditions, such as aging and atherosclerosis, with the conspicuous absence of neuronal degeneration and cancer rarity during the short lifespan of the patients. Cell lines from HGPS patients are characterized by multiple nuclear defects, which include abnormal morphology, altered histone modification patterns, and increased DNA damage. These cell lines provide insight into the molecular pathways including senescence that require lamins A and B1. Here, we review recent data on HGPS phenotypes through the lens of transcriptional deregulation caused by lack of functional lamin A, progerin accumulation, and lamin B1 silencing.
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Affiliation(s)
- Miron Prokocimer
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
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Lund E, Oldenburg AR, Delbarre E, Freberg CT, Duband-Goulet I, Eskeland R, Buendia B, Collas P. Lamin A/C-promoter interactions specify chromatin state-dependent transcription outcomes. Genome Res 2013; 23:1580-9. [PMID: 23861385 PMCID: PMC3787256 DOI: 10.1101/gr.159400.113] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The nuclear lamina is implicated in the organization of the eukaryotic nucleus. Association of nuclear lamins with the genome occurs through large chromatin domains including mostly, but not exclusively, repressed genes. How lamin interactions with regulatory elements modulate gene expression in different cellular contexts is unknown. We show here that in human adipose tissue stem cells, lamin A/C interacts with distinct spatially restricted subpromoter regions, both within and outside peripheral and intra-nuclear lamin-rich domains. These localized interactions are associated with distinct transcriptional outcomes in a manner dependent on local chromatin modifications. Down-regulation of lamin A/C leads to dissociation of lamin A/C from promoters and remodels repressive and permissive histone modifications by enhancing transcriptional permissiveness, but is not sufficient to elicit gene activation. Adipogenic differentiation resets a large number of lamin-genome associations globally and at subpromoter levels and redefines associated transcription outputs. We propose that lamin A/C acts as a modulator of local gene expression outcome through interaction with adjustable sites on promoters, and that these position-dependent transcriptional readouts may be reset upon differentiation.
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Affiliation(s)
- Eivind Lund
- Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, and Norwegian Center for Stem Cell Research, Blindern, 0317 Oslo, Norway
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Donadille B, D'Anella P, Auclair M, Uhrhammer N, Sorel M, Grigorescu R, Ouzounian S, Cambonie G, Boulot P, Laforêt P, Carbonne B, Christin-Maitre S, Bignon YJ, Vigouroux C. Partial lipodystrophy with severe insulin resistance and adult progeria Werner syndrome. Orphanet J Rare Dis 2013; 8:106. [PMID: 23849162 PMCID: PMC3720184 DOI: 10.1186/1750-1172-8-106] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/03/2013] [Indexed: 11/17/2022] Open
Abstract
Background Laminopathies, due to mutations in LMNA, encoding A type-lamins, can lead to premature ageing and/or lipodystrophic syndromes, showing that these diseases could have close physiopathological relationships. We show here that lipodystrophy and extreme insulin resistance can also reveal the adult progeria Werner syndrome linked to mutations in WRN, encoding a RecQ DNA helicase. Methods We analysed the clinical and biological features of two women, aged 32 and 36, referred for partial lipodystrophic syndrome which led to the molecular diagnosis of Werner syndrome. Cultured skin fibroblasts from one patient were studied. Results Two normal-weighted women presented with a partial lipodystrophic syndrome with hypertriglyceridemia and liver steatosis. One of them had also diabetes. Both patients showed a peculiar, striking lipodystrophic phenotype with subcutaneous lipoatrophy of the four limbs contrasting with truncal and abdominal fat accumulation. Their oral glucose tolerance tests showed extremely high levels of insulinemia, revealing major insulin resistance. Low serum levels of sex-hormone binding globulin and adiponectin suggested a post-receptor insulin signalling defect. Other clinical features included bilateral cataracts, greying hair and distal skin atrophy. We observed biallelic WRN null mutations in both women (p.Q748X homozygous, and compound heterozygous p.Q1257X/p.M1329fs). Their fertility was decreased, with preserved menstrual cycles and normal follicle-stimulating hormone levels ruling out premature ovarian failure. However undetectable anti-müllerian hormone and inhibin B indicated diminished follicular ovarian reserve. Insulin-resistance linked ovarian hyperandrogenism could also contribute to decreased fertility, and the two patients became pregnant after initiation of insulin-sensitizers (metformin). Both pregnancies were complicated by severe cervical incompetence, leading to the preterm birth of a healthy newborn in one case, but to a second trimester-abortion in the other. WRN-mutated fibroblasts showed oxidative stress, increased lamin B1 expression, nuclear dysmorphies and premature senescence. Conclusions We show here for the first time that partial lipodystrophy with severe insulin resistance can reveal WRN-linked premature aging syndrome. Increased expression of lamin B1 with altered lamina architecture observed in WRN-mutated fibroblasts could contribute to premature cellular senescence. Primary alterations in DNA replication and/or repair should be considered as possible causes of lipodystrophic syndromes.
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Affiliation(s)
- Bruno Donadille
- Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital Saint-Antoine, Endocrinologie, Diabétologie et Endocrinologie de la Reproduction, F-75012, Paris, France
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Simon DN, Domaradzki T, Hofmann WA, Wilson KL. Lamin A tail modification by SUMO1 is disrupted by familial partial lipodystrophy-causing mutations. Mol Biol Cell 2012; 24:342-50. [PMID: 23243001 PMCID: PMC3564541 DOI: 10.1091/mbc.e12-07-0527] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lamin A tail domains are SUMO1 modified at K420 (nuclear localization signal) and K486 (Ig-fold). K486 modification requires Ig-fold surface residues E460 and D461 and is reduced by familial partial lipodystrophy–causing mutations G465D and K486N. These results suggest novel mechanisms of functional control over lamin A in cells. Lamin filaments are major components of the nucleoskeleton that bind LINC complexes and many nuclear membrane proteins. The tail domain of lamin A directly binds 21 known partners, including actin, emerin, and SREBP1, but how these interactions are regulated is unknown. We report small ubiquitin-like modifier 1 (SUMO1) as a major new posttranslational modification of the lamin A tail. Two SUMO1 modification sites were identified based on in vitro SUMOylation assays and studies of Cos-7 cells. One site (K420) matches the SUMO1 target consensus; the other (K486) does not. On the basis of the position of K486 on the lamin A Ig-fold, we hypothesize the SUMO1 E2 enzyme recognizes a folded structure–dependent motif that includes residues genetically linked to familial partial lipodystrophy (FPLD). Supporting this model, SUMO1-modification of the lamin A tail is reduced by two FPLD-causing mutations, G465D and K486N, and by single mutations in acidic residues E460 and D461. These results suggest a novel mode of functional control over lamin A in cells.
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Affiliation(s)
- Dan N Simon
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Vantyghem MC, Balavoine AS, Douillard C, Defrance F, Dieudonne L, Mouton F, Lemaire C, Bertrand-Escouflaire N, Bourdelle-Hego MF, Devemy F, Evrard A, Gheerbrand D, Girardot C, Gumuche S, Hober C, Topolinski H, Lamblin B, Mycinski B, Ryndak A, Karrouz W, Duvivier E, Merlen E, Cortet C, Weill J, Lacroix D, Wémeau JL. How to diagnose a lipodystrophy syndrome. ANNALES D'ENDOCRINOLOGIE 2012; 73:170-89. [PMID: 22748602 DOI: 10.1016/j.ando.2012.04.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 04/25/2012] [Indexed: 11/15/2022]
Abstract
The spectrum of adipose tissue diseases ranges from obesity to lipodystrophy, and is accompanied by insulin resistance syndrome, which promotes the occurrence of type 2 diabetes, dyslipidemia and cardiovascular complications. Lipodystrophy refers to a group of rare diseases characterized by the generalized or partial absence of adipose tissue, and occurs with or without hypertrophy of adipose tissue in other sites. They are classified as being familial or acquired, and generalized or partial. The genetically determined partial forms usually occur as Dunnigan syndrome, which is a type of laminopathy that can also manifest as muscle, cardiac, neuropathic or progeroid involvement. Gene mutations encoding for PPAR-gamma, Akt2, CIDEC, perilipin and the ZMPSTE 24 enzyme are much more rare. The genetically determined generalized forms are also very rare and are linked to mutations of seipin AGPAT2, FBN1, which is accompanied by Marfan syndrome, or of BANF1, which is characterized by a progeroid syndrome without insulin resistance and with early bone complications. Glycosylation disorders are sometimes involved. Some genetically determined forms have recently been found to be due to autoinflammatory syndromes linked to a proteasome anomaly (PSMB8). They result in a lipodystrophy syndrome that occurs secondarily with fever, dermatosis and panniculitis. Then there are forms that are considered to be acquired. They may be iatrogenic (protease inhibitors in HIV patients, glucocorticosteroids, insulin, graft-versus-host disease, etc.), related to an immune system disease (sequelae of dermatopolymyositis, autoimmune polyendocrine syndromes, particularly associated with type 1 diabetes, Barraquer-Simons and Lawrence syndromes), which are promoted by anomalies of the complement system. Finally, lipomatosis is currently classified as a painful form (adiposis dolorosa or Dercum's disease) or benign symmetric multiple form, also known as Launois-Bensaude syndrome or Madelung's disease, which are sometimes related to mitochondrial DNA mutations, but are usually promoted by alcohol. In addition to the medical management of metabolic syndrome and the sometimes surgical treatment of lipodystrophy, recombinant leptin provides hope for genetically determined lipodystrophy syndromes, whereas modifications in antiretroviral treatment and tesamorelin, a GHRH analog, is effective in the metabolic syndrome of HIV patients. Other therapeutic options will undoubtedly be developed, dependent on pathophysiological advances, which today tend to classify genetically determined lipodystrophy as being related to laminopathy or to lipid droplet disorders.
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Affiliation(s)
- Marie-Christine Vantyghem
- Inserm U859, service d'endocrinologie et maladies métaboliques, hôpital Huriez, CHRU de Lille, 1, rue Polonovski, 59000 Lille, France.
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Vidal C, Bermeo S, Fatkin D, Duque G. Role of the nuclear envelope in the pathogenesis of age-related bone loss and osteoporosis. BONEKEY REPORTS 2012; 1:62. [PMID: 23951459 DOI: 10.1038/bonekey.2012.62] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 03/09/2012] [Indexed: 02/06/2023]
Abstract
The nuclear envelope is the most important border in the eukaryotic cell. The role of the nuclear envelope in cell differentiation and function is determined by a constant interaction between the elements of the nuclear envelope and the transcriptional regulators involved in signal transcription pathways. Among those components of the nuclear envelope, there is a growing evidence that changes in the expression of A-type lamins, which are essential components of the nuclear lamina, are associated with age-related changes in bone affecting the capacity of differentiation of mesenchymal stem cells into osteoblasts, favoring adipogenesis and affecting the function and survival of the osteocytes. Overall, as A-type lamins are considered as the 'guardians of the soma', these proteins are also essential for the integrity and quality of the bone and pivotal for the longevity of the musculoskeletal system.
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Affiliation(s)
- Christopher Vidal
- Ageing Bone Research Program, Sydney Medical School Nepean, The University of Sydney , Nepean Hospital , Penrith, New South Wales, Australia
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