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Odell J, Lammerding J. N-terminal tags impair the ability of lamin A to provide structural support to the nucleus. J Cell Sci 2024; 137:jcs262207. [PMID: 39092499 PMCID: PMC11361635 DOI: 10.1242/jcs.262207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024] Open
Abstract
Lamins are intermediate filament proteins that contribute to numerous cellular functions, including nuclear morphology and mechanical stability. The N-terminal head domain of lamin is crucial for higher order filament assembly and function, yet the effects of commonly used N-terminal tags on lamin function remain largely unexplored. Here, we systematically studied the effect of two differently sized tags on lamin A (LaA) function in a mammalian cell model engineered to allow for precise control of expression of tagged lamin proteins. Untagged, FLAG-tagged and GFP-tagged LaA completely rescued nuclear shape defects when expressed at similar levels in lamin A/C-deficient (Lmna-/-) MEFs, and all LaA constructs prevented increased nuclear envelope ruptures in these cells. N-terminal tags, however, altered the nuclear localization of LaA and impaired the ability of LaA to restore nuclear deformability and to recruit emerin to the nuclear membrane in Lmna-/- MEFs. Our finding that tags impede some LaA functions but not others might explain the partial loss of function phenotypes when tagged lamins are expressed in model organisms and should caution researchers using tagged lamins to study the nucleus.
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Affiliation(s)
- Jacob Odell
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
- Graduate Field of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jan Lammerding
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
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2
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Wang Z, Zhao N, Zhang S, Wang D, Wang S, Liu N. YEATS domain-containing protein GAS41 regulates nuclear shape by working in concert with BRD2 and the mediator complex in colorectal cancer. Pharmacol Res 2024; 206:107283. [PMID: 38964523 DOI: 10.1016/j.phrs.2024.107283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 06/21/2024] [Accepted: 06/22/2024] [Indexed: 07/06/2024]
Abstract
The maintenance of nuclear shape is essential for cellular homeostasis and disruptions in this process have been linked to various pathological conditions, including cancer, laminopathies, and aging. Despite the significance of nuclear shape, the precise molecular mechanisms controlling it are not fully understood. In this study, we have identified the YEATS domain-containing protein 4 (GAS41) as a previously unidentified factor involved in regulating nuclear morphology. Genetic ablation of GAS41 in colorectal cancer cells resulted in significant abnormalities in nuclear shape and inhibited cancer cell proliferation both in vitro and in vivo. Restoration experiments revealed that wild-type GAS41, but not a YEATS domain mutant devoid of histone H3 lysine 27 acetylation or crotonylation (H3K27ac/cr) binding, rescued the aberrant nuclear phenotypes in GAS41-deficient cells, highlighting the importance of GAS41's binding to H3K27ac/cr in nuclear shape regulation. Further experiments showed that GAS41 interacts with H3K27ac/cr to regulate the expression of key nuclear shape regulators, including LMNB1, LMNB2, SYNE4, and LEMD2. Mechanistically, GAS41 recruited BRD2 and the Mediator complex to gene loci of these regulators, promoting their transcriptional activation. Disruption of GAS41-H3K27ac/cr binding caused BRD2, MED14 and MED23 to dissociate from gene loci, leading to nuclear shape abnormalities. Overall, our findings demonstrate that GAS41 collaborates with BRD2 and the Mediator complex to control the expression of crucial nuclear shape regulators.
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Affiliation(s)
- Zhengmin Wang
- Department of Infectious Diseases and Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun 130021, China
| | - Nan Zhao
- Bethune Institute of Epigenetic Medicine, The First Hospital of Jilin University, Changchun 130021, China
| | - Siwei Zhang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130000, China
| | - Deyu Wang
- Bethune Institute of Epigenetic Medicine, The First Hospital of Jilin University, Changchun 130021, China
| | - Shuai Wang
- Bethune Institute of Epigenetic Medicine, The First Hospital of Jilin University, Changchun 130021, China
| | - Nan Liu
- Department of Infectious Diseases and Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun 130021, China.
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3
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Odell J, Lammerding J. N-terminal tags impair the ability of Lamin A to provide structural support to the nucleus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.19.590311. [PMID: 39211210 PMCID: PMC11361184 DOI: 10.1101/2024.04.19.590311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Lamins are intermediate filament proteins that contribute to numerous cellular functions, including nuclear morphology and mechanical stability. The N-terminal head domain of lamin is critical for higher order filament assembly and function, yet the effects of commonly used N-terminal tags on lamin function remain largely unexplored. Here, we systematically studied the effect of two differently sized tags on Lamin A (LaA) function in a mammalian cell model engineered to allow for precise control of expression of tagged lamin proteins. Untagged, FLAG-tagged, and GFP-tagged LaA completely rescued nuclear shape defects when expressed at similar levels in lamin A/C-deficient ( Lmna -/- ) MEFs, and all LaA constructs prevented increased nuclear envelope (NE) ruptures in these cells. N-terminal tags, however, altered the nuclear localization of LaA and impaired the ability of LaA to restore nuclear deformability and to recruit Emerin to the nuclear membrane in Lmna -/- MEFs. Our finding that tags impede some LaA functions but not others may explain the partial loss of function phenotypes when tagged lamins are expressed in model organisms and should caution researchers using tagged lamins to study the nucleus.
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4
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Pho M, Berrada Y, Gunda A, Lavallee A, Chiu K, Padam A, Currey ML, Stephens AD. Actin contraction controls nuclear blebbing and rupture independent of actin confinement. Mol Biol Cell 2024; 35:ar19. [PMID: 38088876 PMCID: PMC10881147 DOI: 10.1091/mbc.e23-07-0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/03/2023] [Accepted: 11/27/2023] [Indexed: 01/14/2024] Open
Abstract
The nucleus is a mechanically stable compartment of the cell that contains the genome and performs many essential functions. Nuclear mechanical components chromatin and lamins maintain nuclear shape, compartmentalization, and function by resisting antagonistic actin contraction and confinement. Studies have yet to compare chromatin and lamins perturbations side-by-side as well as modulated actin contraction while holding confinement constant. To accomplish this, we used nuclear localization signal green fluorescent protein to measure nuclear shape and rupture in live cells with chromatin and lamin perturbations. We then modulated actin contraction while maintaining actin confinement measured by nuclear height. Wild type, chromatin decompaction, and lamin B1 null present bleb-based nuclear deformations and ruptures dependent on actin contraction and independent of actin confinement. Actin contraction inhibition by Y27632 decreased nuclear blebbing and ruptures while activation by CN03 increased rupture frequency. Lamin A/C null results in overall abnormal shape also reliant on actin contraction, but similar blebs and ruptures as wild type. Increased DNA damage is caused by nuclear blebbing or abnormal shape which can be relieved by inhibition of actin contraction which rescues nuclear shape and decreases DNA damage levels in all perturbations. Thus, actin contraction drives nuclear blebbing, bleb-based ruptures, and abnormal shape independent of changes in actin confinement.
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Affiliation(s)
- Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Aachal Gunda
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Anya Lavallee
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Arimita Padam
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Marilena L. Currey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003
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5
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Tan CY, Chan PS, Tan H, Tan SW, Lee CJM, Wang JW, Ye S, Werner H, Loh YJ, Lee YL, Ackers-Johnson M, Foo RSY, Jiang J. Systematic in vivo candidate evaluation uncovers therapeutic targets for LMNA dilated cardiomyopathy and risk of Lamin A toxicity. J Transl Med 2023; 21:690. [PMID: 37840136 PMCID: PMC10577912 DOI: 10.1186/s12967-023-04542-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 09/19/2023] [Indexed: 10/17/2023] Open
Abstract
BACKGROUND Dilated cardiomyopathy (DCM) is a severe, non-ischemic heart disease which ultimately results in heart failure (HF). Decades of research on DCM have revealed diverse aetiologies. Among them, familial DCM is the major form of DCM, with pathogenic variants in LMNA being the second most common form of autosomal dominant DCM. LMNA DCM is a multifactorial and complex disease with no specific treatment thus far. Many studies have demonstrated that perturbing candidates related to various dysregulated pathways ameliorate LMNA DCM. However, it is unknown whether these candidates could serve as potential therapeutic targets especially in long term efficacy. METHODS We evaluated 14 potential candidates including Lmna gene products (Lamin A and Lamin C), key signaling pathways (Tgfβ/Smad, mTor and Fgf/Mapk), calcium handling, proliferation regulators and modifiers of LINC complex function in a cardiac specific Lmna DCM model. Positive candidates for improved cardiac function were further assessed by survival analysis. Suppressive roles and mechanisms of these candidates in ameliorating Lmna DCM were dissected by comparing marker gene expression, Tgfβ signaling pathway activation, fibrosis, inflammation, proliferation and DNA damage. Furthermore, transcriptome profiling compared the differences between Lamin A and Lamin C treatment. RESULTS Cardiac function was restored by several positive candidates (Smad3, Yy1, Bmp7, Ctgf, aYAP1, Sun1, Lamin A, and Lamin C), which significantly correlated with suppression of HF/fibrosis marker expression and cardiac fibrosis in Lmna DCM. Lamin C or Sun1 shRNA administration achieved consistent, prolonged survival which highly correlated with reduced heart inflammation and DNA damage. Importantly, Lamin A treatment improved but could not reproduce long term survival, and Lamin A administration to healthy hearts itself induced DCM. Mechanistically, we identified this lapse as caused by a dose-dependent toxicity of Lamin A, which was independent from its maturation. CONCLUSIONS In vivo candidate evaluation revealed that supplementation of Lamin C or knockdown of Sun1 significantly suppressed Lmna DCM and achieve prolonged survival. Conversely, Lamin A supplementation did not rescue long term survival and may impart detrimental cardiotoxicity risk. This study highlights a potential of advancing Lamin C and Sun1 as therapeutic targets for the treatment of LMNA DCM.
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Affiliation(s)
- Chia Yee Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Pui Shi Chan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Hansen Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Sung Wei Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Chang Jie Mick Lee
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Jiong-Wei Wang
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore
- Centre for NanoMedicine, Nanomedicine Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117609, Singapore
- Department of Physiology, National University of Singapore, Singapore, 117593, Singapore
| | - Shu Ye
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Hendrikje Werner
- Nuevocor Pte Ltd, 1 Biopolis Drive, Amnios, #05-01, Singapore, 138622, Singapore
| | - Ying Jie Loh
- Nuevocor Pte Ltd, 1 Biopolis Drive, Amnios, #05-01, Singapore, 138622, Singapore
| | - Yin Loon Lee
- Nuevocor Pte Ltd, 1 Biopolis Drive, Amnios, #05-01, Singapore, 138622, Singapore
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, Immunos #06-06, Singapore, 138665, Singapore
| | - Matthew Ackers-Johnson
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Roger S Y Foo
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore
| | - Jianming Jiang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
- Centre for Translational Medicine, Cardiovascular Research Institute (CVRI), National University Health System, 14 Medical Drive, Singapore, 117599, Singapore.
- Cardiovascular Disease Translational Research Programme, NUS Yong Loo Lin School of Medicine, 14 Medical Drive, Level 8, Singapore, 117599, Singapore.
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6
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Kim BH, Chung YH, Woo TG, Kang SM, Park S, Park BJ. Progerin, an Aberrant Spliced Form of Lamin A, Is a Potential Therapeutic Target for HGPS. Cells 2023; 12:2299. [PMID: 37759521 PMCID: PMC10527460 DOI: 10.3390/cells12182299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare genetic disorder caused by the mutant protein progerin, which is expressed by the abnormal splicing of the LMNA gene. HGPS affects systemic levels, with the exception of cognition or brain development, in children, showing that cellular aging can occur in the short term. Studying progeria could be useful in unraveling the causes of human aging (as well as fatal age-related disorders). Elucidating the clear cause of HGPS or the development of a therapeutic medicine could improve the quality of life and extend the survival of patients. This review aimed to (i) briefly describe how progerin was discovered as the causative agent of HGPS, (ii) elucidate the puzzling observation of the absence of primary neurological disease in HGPS, (iii) present several studies showing the deleterious effects of progerin and the beneficial effects of its inhibition, and (iv) summarize research to develop a therapy for HGPS and introduce clinical trials for its treatment.
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Affiliation(s)
- Bae-Hoon Kim
- Rare Disease R&D Center, PRG S&T Co., Ltd., Busan 46274, Republic of Korea; (B.-H.K.); (Y.-H.C.); (T.-G.W.)
| | - Yeon-Ho Chung
- Rare Disease R&D Center, PRG S&T Co., Ltd., Busan 46274, Republic of Korea; (B.-H.K.); (Y.-H.C.); (T.-G.W.)
| | - Tae-Gyun Woo
- Rare Disease R&D Center, PRG S&T Co., Ltd., Busan 46274, Republic of Korea; (B.-H.K.); (Y.-H.C.); (T.-G.W.)
| | - So-Mi Kang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 46231, Republic of Korea; (S.-M.K.); (S.P.)
| | - Soyoung Park
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 46231, Republic of Korea; (S.-M.K.); (S.P.)
| | - Bum-Joon Park
- Rare Disease R&D Center, PRG S&T Co., Ltd., Busan 46274, Republic of Korea; (B.-H.K.); (Y.-H.C.); (T.-G.W.)
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 46231, Republic of Korea; (S.-M.K.); (S.P.)
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7
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Wang Y, Dobreva G. Epigenetics in LMNA-Related Cardiomyopathy. Cells 2023; 12:cells12050783. [PMID: 36899919 PMCID: PMC10001118 DOI: 10.3390/cells12050783] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/18/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023] Open
Abstract
Mutations in the gene for lamin A/C (LMNA) cause a diverse range of diseases known as laminopathies. LMNA-related cardiomyopathy is a common inherited heart disease and is highly penetrant with a poor prognosis. In the past years, numerous investigations using mouse models, stem cell technologies, and patient samples have characterized the phenotypic diversity caused by specific LMNA variants and contributed to understanding the molecular mechanisms underlying the pathogenesis of heart disease. As a component of the nuclear envelope, LMNA regulates nuclear mechanostability and function, chromatin organization, and gene transcription. This review will focus on the different cardiomyopathies caused by LMNA mutations, address the role of LMNA in chromatin organization and gene regulation, and discuss how these processes go awry in heart disease.
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Affiliation(s)
- Yinuo Wang
- Department of Cardiovascular Genomics and Epigenomics, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
- German Centre for Cardiovascular Research (DZHK), 68167 Mannheim, Germany
- Correspondence: (Y.W.); (G.D.)
| | - Gergana Dobreva
- Department of Cardiovascular Genomics and Epigenomics, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
- German Centre for Cardiovascular Research (DZHK), 68167 Mannheim, Germany
- Correspondence: (Y.W.); (G.D.)
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8
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Jiang Y, Ji JY. Progerin-Induced Impairment in Wound Healing and Proliferation in Vascular Endothelial Cells. FRONTIERS IN AGING 2022; 3:844885. [PMID: 35821855 PMCID: PMC9261432 DOI: 10.3389/fragi.2022.844885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 01/27/2022] [Indexed: 11/29/2022]
Abstract
Progerin as a mutated isoform of lamin A protein was first known to induce premature atherosclerosis progression in patients with Hutchinson-Gilford progeria syndrome (HGPS), and its role in provoking an inflammatory response in vascular cells and accelerating cell senescence has been investigated recently. However, how progerin triggers endothelial dysfunction that often occurs at the early stage of atherosclerosis in a mechanical environment has not been studied intensively. Here, we generated a stable endothelial cell line that expressed progerin and examined its effects on endothelial wound repair under laminar flow. We found decreased wound healing rate in progerin-expressing ECs under higher shear stress compared with those under low shear. Furthermore, the decreased wound recovery could be due to reduced number of cells at late mitosis, suggesting potential interference by progerin with endothelial proliferation. These findings provided insights into how progerin affects endothelial mechanotransduction and may contribute to the disruption of endothelial integrity in HGPS vasculature, as we continue to examine the mechanistic effect of progerin in shear-induced endothelial functions.
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9
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Wong X, Hoskins VE, Melendez-Perez AJ, Harr JC, Gordon M, Reddy KL. Lamin C is required to establish genome organization after mitosis. Genome Biol 2021; 22:305. [PMID: 34775987 PMCID: PMC8591896 DOI: 10.1186/s13059-021-02516-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/08/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The dynamic 3D organization of the genome is central to gene regulation and development. The nuclear lamina influences genome organization through the tethering of lamina-associated domains (LADs) to the nuclear periphery. Evidence suggests that lamins A and C are the predominant lamins involved in the peripheral association of LADs, potentially serving different roles. RESULTS Here, we examine chromosome architecture in mouse cells in which lamin A or lamin C are downregulated. We find that lamin C, and not lamin A, is required for the 3D organization of LADs and overall chromosome organization. Striking differences in localization are present as cells exit mitosis and persist through early G1 and are linked to differential phosphorylation. Whereas lamin A associates with the nascent nuclear envelope (NE) during telophase, lamin C remains in the interior, surrounding globular LAD aggregates enriched on euchromatic regions. Lamin C association with the NE is delayed until several hours into G1 and correlates temporally and spatially with the post-mitotic NE association of LADs. Post-mitotic LAD association with the NE, and global 3D genome organization, is perturbed only in cells depleted of lamin C, and not lamin A. CONCLUSIONS Lamin C regulates LAD dynamics during exit from mitosis and is a key regulator of genome organization in mammalian cells. This reveals an unexpectedly central role for lamin C in genome organization, including inter-chromosomal LAD-LAD segregation and LAD scaffolding at the NE, raising intriguing questions about the individual and overlapping roles of lamin A/C in cellular function and disease.
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Affiliation(s)
- Xianrong Wong
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Current Address: Laboratory of Developmental and Regenerative Biology, A*STAR Skin Research Labs, Agency for Science, Technology and Research (A*STAR), Immunos, Singapore, 138648, Singapore
| | - Victoria E Hoskins
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Jennifer C Harr
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Biological Sciences, St. Mary's University, San Antonio, TX, 78228, USA
| | - Molly Gordon
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Cell Biology, Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA. .,Sidney Kimmel Comprehensive Cancer Center, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
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10
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Chen NY, Kim PH, Fong LG, Young SG. Nuclear membrane ruptures, cell death, and tissue damage in the setting of nuclear lamin deficiencies. Nucleus 2020; 11:237-249. [PMID: 32910721 PMCID: PMC7529418 DOI: 10.1080/19491034.2020.1815410] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 12/26/2022] Open
Abstract
The nuclear membranes function as a barrier to separate the cell nucleus from the cytoplasm, but this barrier can be compromised by nuclear membrane ruptures, leading to intermixing of nuclear and cytoplasmic contents. Spontaneous nuclear membrane ruptures (i.e., ruptures occurring in the absence of mechanical stress) have been observed in cultured cells, but they are more frequent in the setting of defects or deficiencies in nuclear lamins and when cells are subjected to mechanical stress. Nuclear membrane ruptures in cultured cells have been linked to DNA damage, but the relevance of ruptures to developmental or physiologic processes in vivo has received little attention. Recently, we addressed that issue by examining neuronal migration in the cerebral cortex, a developmental process that subjects the cell nucleus to mechanical stress. In the setting of lamin B1 deficiency, we observed frequent nuclear membrane ruptures in migrating neurons in the developing cerebral cortex and showed that those ruptures are likely the cause of observed DNA damage, neuronal cell death, and profound neuropathology. In this review, we discuss the physiologic relevance of nuclear membrane ruptures, with a focus on migrating neurons in cell culture and in the cerebral cortex of genetically modified mice.
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Affiliation(s)
- Natalie Y. Chen
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - Paul H. Kim
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - Loren G. Fong
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - Stephen G. Young
- Department of Medicine, University of California, Los Angeles, CA, USA
- Department of Human Genetics, University of California, Los Angeles, CA, USA
- Department of Molecular Biology Institute, University of California, Los Angeles, CA, USA
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11
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de Toledo M, Lopez-Mejia IC, Cavelier P, Pratlong M, Barrachina C, Gromada X, Annicotte JS, Tazi J, Chavey C. Lamin C Counteracts Glucose Intolerance in Aging, Obesity, and Diabetes Through β-Cell Adaptation. Diabetes 2020; 69:647-660. [PMID: 32005707 DOI: 10.2337/db19-0377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 01/27/2020] [Indexed: 11/13/2022]
Abstract
Aging-dependent changes in tissue function are associated with the development of metabolic diseases. However, the molecular connections linking aging, obesity, and diabetes remain unclear. Lamin A, lamin C, and progerin, products of the Lmna gene, have antagonistic functions on energy metabolism and life span. Lamin C, albeit promoting obesity, increases life span, suggesting that this isoform is crucial for maintaining healthy conditions under metabolic stresses. Because β-cell loss during obesity or aging leads to diabetes, we investigated the contribution of lamin C to β-cell function in physiopathological conditions. We demonstrate that aged lamin C only-expressing mice (Lmna LCS/LCS ) become obese but remain glucose tolerant due to adaptive mechanisms including increased β-cell mass and insulin secretion. Triggering diabetes in young mice revealed that Lmna LCS/LCS animals normalize their fasting glycemia by both increasing insulin secretion and regenerating β-cells. Genome-wide analyses combined to functional analyses revealed an increase of mitochondrial biogenesis and global translational rate in Lmna LCS/LCS islets, two major processes involved in insulin secretion. Altogether, our results demonstrate for the first time that the sole expression of lamin C protects from glucose intolerance through a β-cell-adaptive transcriptional program during metabolic stresses, highlighting Lmna gene processing as a new therapeutic target for diabetes treatment.
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Affiliation(s)
- Marion de Toledo
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | | | - Patricia Cavelier
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Marine Pratlong
- Montpellier GenomiX, Biocampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Célia Barrachina
- Montpellier GenomiX, Biocampus Montpellier, CNRS, INSERM, University of Montpellier, Montpellier, France
| | - Xavier Gromada
- Université Lille, CNRS, CHU Lille, Institut Pasteur de Lille, UMR 8199, European Genomic Institute for Diabetes, Lille, France
| | - Jean-Sébastien Annicotte
- Université Lille, CNRS, CHU Lille, Institut Pasteur de Lille, UMR 8199, European Genomic Institute for Diabetes, Lille, France
| | - Jamal Tazi
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Carine Chavey
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
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12
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Saxena S, Kumar S. Pharmacotherapy to gene editing: potential therapeutic approaches for Hutchinson-Gilford progeria syndrome. GeroScience 2020; 42:467-494. [PMID: 32048129 PMCID: PMC7205988 DOI: 10.1007/s11357-020-00167-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/04/2020] [Indexed: 12/11/2022] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS), commonly called progeria, is an extremely rare disorder that affects only one child per four million births. It is characterized by accelerated aging in affected individuals leading to premature death at an average age of 14.5 years due to cardiovascular complications. The main cause of HGPS is a sporadic autosomal dominant point mutation in LMNA gene resulting in differently spliced lamin A protein known as progerin. Accumulation of progerin under nuclear lamina and activation of its downstream effectors cause perturbation in cellular morphology and physiology which leads to a systemic disorder that mainly impairs the cardiovascular system, bones, skin, and overall growth. Till now, no cure has been found for this catastrophic disorder; however, several therapeutic strategies are under development. The current review focuses on the overall progress in the field of therapeutic approaches for the management/cure of HGPS. We have also discussed the new disease models that have been developed for the study of this rare disorder. Moreover, we have highlighted the therapeutic application of extracellular vesicles derived from stem cells against aging and aging-related disorders and, therefore, suggest the same for the treatment of HGPS.
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Affiliation(s)
- Saurabh Saxena
- Department of Medical Laboratory Sciences, Lovely Professional University, Jalandhar - Delhi G.T. Road, Phagwara, Punjab, 144411, India.
| | - Sanjeev Kumar
- Faculty of Technology and Sciences, Lovely Professional University, Jalandhar - Delhi G.T. Road, Phagwara, Punjab, 144411, India
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13
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Heizer PJ, Yang Y, Tu Y, Kim PH, Chen NY, Hu Y, Yoshinaga Y, de Jong PJ, Vergnes L, Morales JE, Li RL, Jackson N, Reue K, Young SG, Fong LG. Deficiency in ZMPSTE24 and resulting farnesyl-prelamin A accumulation only modestly affect mouse adipose tissue stores. J Lipid Res 2020; 61:413-421. [PMID: 31941672 DOI: 10.1194/jlr.ra119000593] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/14/2020] [Indexed: 11/20/2022] Open
Abstract
Zinc metallopeptidase STE24 (ZMPSTE24) is essential for the conversion of farnesyl-prelamin A to mature lamin A, a key component of the nuclear lamina. In the absence of ZMPSTE24, farnesyl-prelamin A accumulates in the nucleus and exerts toxicity, causing a variety of disease phenotypes. By ∼4 months of age, both male and female Zmpste24 -/- mice manifest a near-complete loss of adipose tissue, but it has never been clear whether this phenotype is a direct consequence of farnesyl-prelamin A toxicity in adipocytes. To address this question, we generated a conditional knockout Zmpste24 allele and used it to create adipocyte-specific Zmpste24-knockout mice. To boost farnesyl-prelamin A levels, we bred in the "prelamin A-only" Lmna allele. Gene expression, immunoblotting, and immunohistochemistry experiments revealed that adipose tissue in these mice had decreased Zmpste24 expression along with strikingly increased accumulation of prelamin A. In male mice, Zmpste24 deficiency in adipocytes was accompanied by modest changes in adipose stores (an 11% decrease in body weight, a 23% decrease in body fat mass, and significantly smaller gonadal and inguinal white adipose depots). No changes in adipose stores were detected in female mice, likely because prelamin A expression in adipose tissue is lower in female mice. Zmpste24 deficiency in adipocytes did not alter the number of macrophages in adipose tissue, nor did it alter plasma levels of glucose, triglycerides, or fatty acids. We conclude that ZMPSTE24 deficiency in adipocytes, and the accompanying accumulation of farnesyl-prelamin A, reduces adipose tissue stores, but only modestly and only in male mice.
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Affiliation(s)
- Patrick J Heizer
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Ye Yang
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Paul H Kim
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Natalie Y Chen
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yan Hu
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yuko Yoshinaga
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Laurent Vergnes
- Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Jazmin E Morales
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Robert L Li
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Nicholas Jackson
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Karen Reue
- Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095 .,Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Loren G Fong
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
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14
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Qadir MI, Bukhat S, Rasul S, Manzoor H, Manzoor M. RNA therapeutics: Identification of novel targets leading to drug discovery. J Cell Biochem 2019; 121:898-929. [DOI: 10.1002/jcb.29364] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 08/20/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Muhammad Imran Qadir
- Institute of Molecular Biology and Biotechnology Bahauddin Zakariya University Multan Pakistan
| | - Sherien Bukhat
- Institute of Molecular Biology and Biotechnology Bahauddin Zakariya University Multan Pakistan
| | - Sumaira Rasul
- Institute of Molecular Biology and Biotechnology Bahauddin Zakariya University Multan Pakistan
| | - Hamid Manzoor
- Institute of Molecular Biology and Biotechnology Bahauddin Zakariya University Multan Pakistan
| | - Majid Manzoor
- College of Pharmaceutical Sciences Zhejiang University Hangzhou China
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15
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Cellular and Animal Models of Striated Muscle Laminopathies. Cells 2019; 8:cells8040291. [PMID: 30934932 PMCID: PMC6523539 DOI: 10.3390/cells8040291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/18/2019] [Accepted: 03/25/2019] [Indexed: 01/12/2023] Open
Abstract
The lamin A/C (LMNA) gene codes for nuclear intermediate filaments constitutive of the nuclear lamina. LMNA has 12 exons and alternative splicing of exon 10 results in two major isoforms—lamins A and C. Mutations found throughout the LMNA gene cause a group of diseases collectively known as laminopathies, of which the type, diversity, penetrance and severity of phenotypes can vary from one individual to the other, even between individuals carrying the same mutation. The majority of the laminopathies affect cardiac and/or skeletal muscles. The underlying molecular mechanisms contributing to such tissue-specific phenotypes caused by mutations in a ubiquitously expressed gene are not yet well elucidated. This review will explore the different phenotypes observed in established models of striated muscle laminopathies and their respective contributions to advancing our understanding of cardiac and skeletal muscle-related laminopathies. Potential future directions for developing effective treatments for patients with lamin A/C mutation-associated cardiac and/or skeletal muscle conditions will be discussed.
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16
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Abstract
Structural links from the nucleus to the cytoskeleton and to the extracellular environment play a role in direct mechanosensing by nuclear factors. Here, we highlight recent studies that illustrate nuclear mechanosensation processes ranging from DNA repair and nuclear protein phospho-modulation to chromatin reorganization, lipase activation by dilation, and reversible rupture with the release of nuclear factors. Recent progresses demonstrate that these mechanosensing processes lead to modulation of gene expression such as those involved in the regulation of cytoskeletal programs and introduce copy number variations. The nuclear lamina protein lamin A has a recurring role, and various biophysical analyses prove helpful in clarifying mechanisms. The various recent observations provide further motivation to understand the regulation of nuclear mechanosensing pathways in both physiological and pathological contexts.
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17
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Xia Y, Ivanovska IL, Zhu K, Smith L, Irianto J, Pfeifer CR, Alvey CM, Ji J, Liu D, Cho S, Bennett RR, Liu AJ, Greenberg RA, Discher DE. Nuclear rupture at sites of high curvature compromises retention of DNA repair factors. J Cell Biol 2018; 217:3796-3808. [PMID: 30171044 PMCID: PMC6219729 DOI: 10.1083/jcb.201711161] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 05/24/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023] Open
Abstract
The nucleus is physically linked to the cytoskeleton, adhesions, and extracellular matrix-all of which sustain forces, but their relationships to DNA damage are obscure. We show that nuclear rupture with cytoplasmic mislocalization of multiple DNA repair factors correlates with high nuclear curvature imposed by an external probe or by cell attachment to either aligned collagen fibers or stiff matrix. Mislocalization is greatly enhanced by lamin A depletion, requires hours for nuclear reentry, and correlates with an increase in pan-nucleoplasmic foci of the DNA damage marker γH2AX. Excess DNA damage is rescued in ruptured nuclei by cooverexpression of multiple DNA repair factors as well as by soft matrix or inhibition of actomyosin tension. Increased contractility has the opposite effect, and stiff tumors with low lamin A indeed exhibit increased nuclear curvature, more frequent nuclear rupture, and excess DNA damage. Additional stresses likely play a role, but the data suggest high curvature promotes nuclear rupture, which compromises retention of DNA repair factors and favors sustained damage.
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Affiliation(s)
- Yuntao Xia
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Irena L. Ivanovska
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Kuangzheng Zhu
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Lucas Smith
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Jerome Irianto
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Charlotte R. Pfeifer
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Cory M. Alvey
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA,Graduate Group, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA
| | - Jiazheng Ji
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Dazhen Liu
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Sangkyun Cho
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA
| | - Rachel R. Bennett
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Graduate Group, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA
| | - Andrea J. Liu
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Graduate Group, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA
| | - Roger A. Greenberg
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Cancer Biology, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Dennis E. Discher
- Physical Sciences Oncology Center at Penn, University of Pennsylvania, Philadelphia, PA ,Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA,Graduate Group, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA,Correspondence to Dennis E. Discher:
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18
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Brull A, Morales Rodriguez B, Bonne G, Muchir A, Bertrand AT. The Pathogenesis and Therapies of Striated Muscle Laminopathies. Front Physiol 2018; 9:1533. [PMID: 30425656 PMCID: PMC6218675 DOI: 10.3389/fphys.2018.01533] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/11/2018] [Indexed: 01/04/2023] Open
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a genetic condition characterized by early contractures, skeletal muscle weakness, and cardiomyopathy. During the last 20 years, various genetic approaches led to the identification of causal genes of EDMD and related disorders, all encoding nuclear envelope proteins. By their respective localization either at the inner nuclear membrane or the outer nuclear membrane, these proteins interact with each other and establish a connection between the nucleus and the cytoskeleton. Beside this physical link, these proteins are also involved in mechanotransduction, responding to environmental cues, such as increased tension of the cytoskeleton, by the activation or repression of specific sets of genes. This ability of cells to adapt to environmental conditions is altered in EDMD. Increased knowledge on the pathophysiology of EDMD has led to the development of drug or gene therapies that have been tested on mouse models. This review proposed an overview of the functions played by the different proteins involved in EDMD and related disorders and the current therapeutic approaches tested so far.
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Affiliation(s)
- Astrid Brull
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Blanca Morales Rodriguez
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France.,Sanofi R&D, Chilly Mazarin, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Anne T Bertrand
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
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19
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Kang SM, Yoon MH, Park BJ. Laminopathies; Mutations on single gene and various human genetic diseases. BMB Rep 2018; 51:327-337. [PMID: 29764566 PMCID: PMC6089866 DOI: 10.5483/bmbrep.2018.51.7.113] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Indexed: 01/13/2023] Open
Abstract
Lamin A and its alternative splicing product Lamin C are the key intermediate filaments (IFs) of the inner nuclear membrane intermediate filament. Lamin A/C forms the inner nuclear mesh with Lamin B and works as a frame with a nuclear shape. In addition to supporting the function of nucleus, nuclear lamins perform important roles such as holding the nuclear pore complex and chromatin. However, mutations on the Lamin A or Lamin B related proteins induce various types of human genetic disorders and diseases including premature aging syndromes, muscular dystrophy, lipodystrophy and neuropathy. In this review, we briefly overview the relevance of genetic mutations of Lamin A, human disorders and laminopathies. We also discuss a mouse model for genetic diseases. Finally, we describe the current treatment for laminopathies. [BMB Reports 2018; 51(7): 327-337].
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Affiliation(s)
- So-Mi Kang
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 46241, Korea
| | - Min-Ho Yoon
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 46241, Korea
| | - Bum-Joon Park
- Department of Molecular Biology, College of Natural Science, Pusan National University, Busan 46241, Korea
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20
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Direct Force Probe for Nuclear Mechanics. Methods Mol Biol 2018. [PMID: 30141040 DOI: 10.1007/978-1-4939-8691-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
We describe a recently reported method for directly applying a known, nanonewton-scale force to the nucleus in a living, intact cell. First, a suction seal is applied on the nuclear surface using a micropipette. Then, the micropipette is translated away from the nucleus. The nucleus deforms and translates with the moving micropipette and then eventually detaches from the micropipette and recovers (roughly) its original shape and position. At the point of detachment, the resisting force (from the deformed nucleus and connected cytoskeleton) balances the suction force. Because the suction force is precisely known and reproducibly applied, this method therefore allows comparisons of nuclear response across disruptions to the cytoskeleton, nucleus, or cell. This method is useful for quantifying nuclear elastic properties in its native, integrated environment.
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21
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Harhouri K, Navarro C, Depetris D, Mattei MG, Nissan X, Cau P, De Sandre-Giovannoli A, Lévy N. MG132-induced progerin clearance is mediated by autophagy activation and splicing regulation. EMBO Mol Med 2018; 9:1294-1313. [PMID: 28674081 PMCID: PMC5582415 DOI: 10.15252/emmm.201607315] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hutchinson–Gilford progeria syndrome (HGPS) is a lethal premature and accelerated aging disease caused by a de novo point mutation in LMNA encoding A‐type lamins. Progerin, a truncated and toxic prelamin A issued from aberrant splicing, accumulates in HGPS cells' nuclei and is a hallmark of the disease. Small amounts of progerin are also produced during normal aging. We show that progerin is sequestered into abnormally shaped promyelocytic nuclear bodies, identified as novel biomarkers in late passage HGPS cell lines. We found that the proteasome inhibitor MG132 induces progerin degradation through macroautophagy and strongly reduces progerin production through downregulation of SRSF‐1 and SRSF‐5 accumulation, controlling prelamin A mRNA aberrant splicing. MG132 treatment improves cellular HGPS phenotypes. MG132 injection in skeletal muscle of LmnaG609G/G609G mice locally reduces SRSF‐1 expression and progerin levels. Altogether, we demonstrate progerin reduction based on MG132 dual action and shed light on a promising class of molecules toward a potential therapy for children with HGPS.
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Affiliation(s)
- Karim Harhouri
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France
| | - Claire Navarro
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France
| | - Danielle Depetris
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France
| | - Marie-Geneviève Mattei
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France
| | - Xavier Nissan
- CECS, I-STEM, Institut des cellules Souches pour le Traitement et l'Etude des maladies Monogéniques, AFM, Evry, France
| | - Pierre Cau
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France.,AP-HM, Hôpital la Timone, Service de Biologie Cellulaire, Marseille, France
| | - Annachiara De Sandre-Giovannoli
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France.,AP-HM, Hôpital la Timone, Département de Génétique Médicale, Marseille, France
| | - Nicolas Lévy
- Aix Marseille Univ, INSERM, GMGF (Génétique Médicale et Génomique Fonctionnelle), Marseille, France .,AP-HM, Hôpital la Timone, Département de Génétique Médicale, Marseille, France
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22
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Simon DN, Wriston A, Fan Q, Shabanowitz J, Florwick A, Dharmaraj T, Peterson SB, Gruenbaum Y, Carlson CR, Grønning-Wang LM, Hunt DF, Wilson KL. OGT ( O-GlcNAc Transferase) Selectively Modifies Multiple Residues Unique to Lamin A. Cells 2018; 7:E44. [PMID: 29772801 PMCID: PMC5981268 DOI: 10.3390/cells7050044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 12/31/2022] Open
Abstract
The LMNA gene encodes lamins A and C with key roles in nuclear structure, signaling, gene regulation, and genome integrity. Mutations in LMNA cause over 12 diseases ('laminopathies'). Lamins A and C are identical for their first 566 residues. However, they form separate filaments in vivo, with apparently distinct roles. We report that lamin A is β-O-linked N-acetylglucosamine-(O-GlcNAc)-modified in human hepatoma (Huh7) cells and in mouse liver. In vitro assays with purified O-GlcNAc transferase (OGT) enzyme showed robust O-GlcNAcylation of recombinant mature lamin A tails (residues 385⁻646), with no detectable modification of lamin B1, lamin C, or 'progerin' (Δ50) tails. Using mass spectrometry, we identified 11 O-GlcNAc sites in a 'sweet spot' unique to lamin A, with up to seven sugars per peptide. Most sites were unpredicted by current algorithms. Double-mutant (S612A/T643A) lamin A tails were still robustly O-GlcNAc-modified at seven sites. By contrast, O-GlcNAcylation was undetectable on tails bearing deletion Δ50, which causes Hutchinson⁻Gilford progeria syndrome, and greatly reduced by deletion Δ35. We conclude that residues deleted in progeria are required for substrate recognition and/or modification by OGT in vitro. Interestingly, deletion Δ35, which does not remove the majority of identified O-GlcNAc sites, does remove potential OGT-association motifs (lamin A residues 622⁻625 and 639⁻645) homologous to that in mouse Tet1. These biochemical results are significant because they identify a novel molecular pathway that may profoundly influence lamin A function. The hypothesis that lamin A is selectively regulated by OGT warrants future testing in vivo, along with two predictions: genetic variants may contribute to disease by perturbing OGT-dependent regulation, and nutrient or other stresses might cause OGT to misregulate wildtype lamin A.
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Affiliation(s)
- Dan N Simon
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Amanda Wriston
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| | - Qiong Fan
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| | - Alyssa Florwick
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Tejas Dharmaraj
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Sherket B Peterson
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram Jerusalem 91904, Israel.
| | - Cathrine R Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway.
| | - Line M Grønning-Wang
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
| | - Donald F Hunt
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
- Department of Pathology, University of Virginia, Charlottesville, VA 22904, USA.
| | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
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23
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Brady GF, Kwan R, Cunha JB, Elenbaas JS, Omary MB. Lamins and Lamin-Associated Proteins in Gastrointestinal Health and Disease. Gastroenterology 2018; 154:1602-1619.e1. [PMID: 29549040 PMCID: PMC6038707 DOI: 10.1053/j.gastro.2018.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/04/2018] [Accepted: 03/06/2018] [Indexed: 02/07/2023]
Abstract
The nuclear lamina is a multi-protein lattice composed of A- and B-type lamins and their associated proteins. This protein lattice associates with heterochromatin and integral inner nuclear membrane proteins, providing links among the genome, nucleoskeleton, and cytoskeleton. In the 1990s, mutations in EMD and LMNA were linked to Emery-Dreifuss muscular dystrophy. Since then, the number of diseases attributed to nuclear lamina defects, including laminopathies and other disorders, has increased to include more than 20 distinct genetic syndromes. Studies of patients and mouse genetic models have pointed to important roles for lamins and their associated proteins in the function of gastrointestinal organs, including liver and pancreas. We review the interactions and functions of the lamina in relation to the nuclear envelope and genome, the ways in which its dysfunction is thought to contribute to human disease, and possible avenues for targeted therapies.
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,To whom correspondence should be addressed: University of Michigan Medical School, Division of Gastroenterology, Department of Internal Medicine, 1137 Catherine St., Ann Arbor, MI 48109-5622.
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Juliana Bragazzi Cunha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jared S. Elenbaas
- Medical Scientist Training Program, Washington University, St Louis, Missouri
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,Ǻbo Akademi University, Turku, Finland
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24
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Tu Y, Sánchez-Iglesias S, Araújo-Vilar D, Fong LG, Young SG. LMNA missense mutations causing familial partial lipodystrophy do not lead to an accumulation of prelamin A. Nucleus 2017; 7:512-521. [PMID: 27841971 DOI: 10.1080/19491034.2016.1242542] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A variety of missense mutations in LMNA (the gene for lamin C and prelamin A) cause familial partial lipodystrophy (FPLD), a disease associated with reduced adipose tissue, particularly in the limbs. Several studies have reported that fibroblasts from FPLD subjects have an accumulation of prelamin A. Those findings were intriguing but also perplexing because many of the LMNA missense mutations associated with lipodystrophy are located in sequences distant from the sequences required for the farnesylation of prelamin A and ZMPSTE24-mediated conversion of prelamin A to mature lamin A. Here, we revisited the issue of prelamin A accumulation in the setting of FPLD mutations. We used western blots with lamin A/C antibodies and prelamin A-specific monoclonal antibodies to assess prelamin A levels in wild-type fibroblasts and fibroblasts carrying LMNA mutations associated with lipodystrophy (R482W, I299V, C591F, T528M). None of the mutant fibroblasts exhibited an accumulation of prelamin A. Also, the amount of prelamin A accumulation in response to lopinavir (an inhibitor of ZMPSTE24) was similar in wild-type and mutant fibroblasts. Thus, the LMNA lipodystrophy mutations that we examined did not lead to prelamin A accumulation, nor did they render those cells more susceptible to prelamin A accumulation when ZMPSTE24 was inhibited by lopinavir.
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Affiliation(s)
- Yiping Tu
- a Department of Medicine , David Geffen School of Medicine, University of California , Los Angeles , CA , USA
| | - Sofía Sánchez-Iglesias
- c UETeM-Molecular Pathology Group , IDIS-CIMUS, University of Santiago de Compostela , Galicia , Spain
| | - David Araújo-Vilar
- c UETeM-Molecular Pathology Group , IDIS-CIMUS, University of Santiago de Compostela , Galicia , Spain
| | - Loren G Fong
- a Department of Medicine , David Geffen School of Medicine, University of California , Los Angeles , CA , USA
| | - Stephen G Young
- a Department of Medicine , David Geffen School of Medicine, University of California , Los Angeles , CA , USA.,b Human Genetics , David Geffen School of Medicine, University of California , Los Angeles , CA , USA
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Mehmood S, Marcoux J, Gault J, Quigley A, Michaelis S, Young SG, Carpenter EP, Robinson CV. Mass spectrometry captures off-target drug binding and provides mechanistic insights into the human metalloprotease ZMPSTE24. Nat Chem 2016; 8:1152-1158. [PMID: 27874871 PMCID: PMC5123592 DOI: 10.1038/nchem.2591] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 07/05/2016] [Indexed: 12/25/2022]
Abstract
Off-target binding of hydrophobic drugs can lead to unwanted side effects, either through specific or non-specific binding to unintended membrane protein targets. However, distinguishing the binding of drugs to membrane proteins from that of detergents, lipids and cofactors is challenging. Here, we use high-resolution mass spectrometry to study the effects of HIV protease inhibitors on the human zinc metalloprotease ZMPSTE24. This intramembrane protease plays a major role in converting prelamin A to mature lamin A. We monitored the proteolysis of farnesylated prelamin A peptide by ZMPSTE24 and unexpectedly found retention of the C-terminal peptide product with the enzyme. We also resolved binding of zinc, lipids and HIV protease inhibitors and showed that drug binding blocked prelamin A peptide cleavage and conferred stability to ZMPSTE24. Our results not only have relevance for the progeria-like side effects of certain HIV protease inhibitor drugs, but also highlight new approaches for documenting off-target drug binding.
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Affiliation(s)
- Shahid Mehmood
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Julien Marcoux
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Joseph Gault
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Andrew Quigley
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Susan Michaelis
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Stephen G Young
- Departments of Medicine and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Elisabeth P Carpenter
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Carol V Robinson
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
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26
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The effect of the lamin A and its mutants on nuclear structure, cell proliferation, protein stability, and mobility in embryonic cells. Chromosoma 2016; 126:501-517. [PMID: 27534416 PMCID: PMC5509783 DOI: 10.1007/s00412-016-0610-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 01/26/2023]
Abstract
LMNA gene encodes for nuclear intermediate filament proteins lamin A/C. Mutations in this gene lead to a spectrum of genetic disorders, collectively referred to as laminopathies. Lamin A/C are widely expressed in most differentiated somatic cells but not in early embryos and some undifferentiated cells. To investigate the role of lamin A/C in cell phenotype maintenance and differentiation, which could be a determinant of the pathogenesis of laminopathies, we examined the role played by exogenous lamin A and its mutants in differentiated cell lines (HeLa, NHDF) and less-differentiated HEK 293 cells. We introduced exogenous wild-type and mutated (H222P, L263P, E358K D446V, and ∆50) lamin A into different cell types and analyzed proteins’ impact on proliferation, protein mobility, and endogenous nuclear envelope protein distribution. The mutants give rise to a broad spectrum of nuclear phenotypes and relocate lamin C. The mutations ∆50 and D446V enhance proliferation in comparison to wild-type lamin A and control cells, but no changes in exogenous protein mobility measured by FRAP were observed. Interestingly, although transcripts for lamins A and C are at similar level in HEK 293 cells, only lamin C protein is detected in western blots. Also, exogenous lamin A and its mutants, when expressed in HEK 293 cells underwent posttranscriptional processing. Overall, our results provide new insight into the maintenance of lamin A in less-differentiated cells. Embryonic cells are very sensitive to lamin A imbalance, and its upregulation disturbs lamin C, which may influence gene expression and many regulatory pathways.
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Razafsky D, Ward C, Potter C, Zhu W, Xue Y, Kefalov VJ, Fong LG, Young SG, Hodzic D. Lamin B1 and lamin B2 are long-lived proteins with distinct functions in retinal development. Mol Biol Cell 2016; 27:1928-37. [PMID: 27075175 PMCID: PMC4907726 DOI: 10.1091/mbc.e16-03-0143] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/06/2016] [Accepted: 04/08/2016] [Indexed: 11/11/2022] Open
Abstract
Lamin B1 and lamin B2 are essential building blocks of the nuclear lamina, a filamentous meshwork lining the nucleoplasmic side of the inner nuclear membrane. Deficiencies in lamin B1 and lamin B2 impair neurodevelopment, but distinct functions for the two proteins in the development and homeostasis of the CNS have been elusive. Here we show that embryonic depletion of lamin B1 in retinal progenitors and postmitotic neurons affects nuclear integrity, leads to the collapse of the laminB2 meshwork, impairs neuronal survival, and markedly reduces the cellularity of adult retinas. In stark contrast, a deficiency of lamin B2 in the embryonic retina has no obvious effect on lamin B1 localization or nuclear integrity in embryonic retinas, suggesting that lamin B1, but not lamin B2, is strictly required for nucleokinesis during embryonic neurogenesis. However, the absence of lamin B2 prevents proper lamination of adult retinal neurons, impairs synaptogenesis, and reduces cone photoreceptor survival. We also show that lamin B1 and lamin B2 are extremely long-lived proteins in rod and cone photoreceptors. OF interest, a complete absence of both proteins during postnatal life has little or no effect on the survival and function of cone photoreceptors.
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Affiliation(s)
- David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Candace Ward
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Chloe Potter
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Wanqiu Zhu
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Yunlu Xue
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095 Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095 Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
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Lee JM, Nobumori C, Tu Y, Choi C, Yang SH, Jung HJ, Vickers TA, Rigo F, Bennett CF, Young SG, Fong LG. Modulation of LMNA splicing as a strategy to treat prelamin A diseases. J Clin Invest 2016; 126:1592-602. [PMID: 26999604 DOI: 10.1172/jci85908] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/14/2016] [Indexed: 01/08/2023] Open
Abstract
The alternatively spliced products of LMNA, lamin C and prelamin A (the precursor to lamin A), are produced in similar amounts in most tissues and have largely redundant functions. This redundancy suggests that diseases, such as Hutchinson-Gilford progeria syndrome (HGPS), that are caused by prelamin A-specific mutations could be treated by shifting the output of LMNA more toward lamin C. Here, we investigated mechanisms that regulate LMNA mRNA alternative splicing and assessed the feasibility of reducing prelamin A expression in vivo. We identified an exon 11 antisense oligonucleotide (ASO) that increased lamin C production at the expense of prelamin A when transfected into mouse and human fibroblasts. The same ASO also reduced the expression of progerin, the mutant prelamin A protein in HGPS, in fibroblasts derived from patients with HGPS. Mechanistic studies revealed that the exon 11 sequences contain binding sites for serine/arginine-rich splicing factor 2 (SRSF2), and SRSF2 knockdown lowered lamin A production in cells and in murine tissues. Moreover, administration of the exon 11 ASO reduced lamin A expression in wild-type mice and progerin expression in an HGPS mouse model. Together, these studies identify ASO-mediated reduction of prelamin A as a potential strategy to treat prelamin A-specific diseases.
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Truttmann MC, Wu Q, Stiegeler S, Duarte JN, Ingram J, Ploegh HL. HypE-specific nanobodies as tools to modulate HypE-mediated target AMPylation. J Biol Chem 2015; 290:9087-100. [PMID: 25678711 DOI: 10.1074/jbc.m114.634287] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Indexed: 11/06/2022] Open
Abstract
The covalent addition of mono-AMP to target proteins (AMPylation) by Fic domain-containing proteins is a poorly understood, yet highly conserved post-translational modification. Here, we describe the generation, evaluation, and application of four HypE-specific nanobodies: three that inhibit HypE-mediated target AMPylation in vitro and one that acts as an activator. All heavy chain-only antibody variable domains bind HypE when expressed as GFP fusions in intact cells. We observed localization of HypE at the nuclear envelope and further identified histones H2-H4, but not H1, as novel in vitro targets of the human Fic protein. Its role in histone modification provides a possible link between AMPylation and regulation of gene expression.
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Affiliation(s)
- Matthias C Truttmann
- From the Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142 and
| | - Qin Wu
- From the Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142 and
| | - Sarah Stiegeler
- From the Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142 and
| | - Joao N Duarte
- From the Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142 and
| | - Jessica Ingram
- From the Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142 and
| | - Hidde L Ploegh
- From the Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142 and the Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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30
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Davies BSJ, Coffinier C, Yang SH, Barnes RH, Jung HJ, Young SG, Fong LG. Investigating the purpose of prelamin A processing. Nucleus 2014. [DOI: 10.4161/nucl.13723] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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31
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An absence of nuclear lamins in keratinocytes leads to ichthyosis, defective epidermal barrier function, and intrusion of nuclear membranes and endoplasmic reticulum into the nuclear chromatin. Mol Cell Biol 2014; 34:4534-44. [PMID: 25312645 DOI: 10.1128/mcb.00997-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
B-type lamins (lamins B1 and B2) have been considered to be essential for many crucial functions in the cell nucleus (e.g., DNA replication and mitotic spindle formation). However, this view has been challenged by the observation that an absence of both B-type lamins in keratinocytes had no effect on cell proliferation or the development of skin and hair. The latter findings raised the possibility that the functions of B-type lamins are subserved by lamins A and C. To explore that idea, we created mice lacking all nuclear lamins in keratinocytes. Those mice developed ichthyosis and a skin barrier defect, which led to death from dehydration within a few days after birth. Microscopy of nuclear-lamin-deficient skin revealed hyperkeratosis and a disordered stratum corneum with an accumulation of neutral lipid droplets; however, BrdU incorporation into keratinocytes was normal. Skin grafting experiments confirmed the stratum corneum abnormalities and normal BrdU uptake. Interestingly, the absence of nuclear lamins in keratinocytes resulted in an interspersion of nuclear/endoplasmic reticulum membranes with the chromatin. Thus, a key function of the nuclear lamina is to serve as a "fence" and prevent the incursion of cytoplasmic organelles into the nuclear chromatin.
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32
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Do lamin A and lamin C have unique roles? Chromosoma 2014; 124:1-12. [PMID: 25283634 DOI: 10.1007/s00412-014-0484-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 08/12/2014] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
Abstract
The A-type lamins, lamin A and lamin C, generated from a single gene, LMNA, are major structural components of the nuclear lamina. The two alternative splice products have mostly been studied together because they have been considered to be interchangeable. However, several lines of evidence indicate that in spite of being generated from the same gene and having high similarities in their primary sequences, the two isoforms are not equivalent in different biological aspects in both health and disease. The key question is whether they have both overlapping and unique functions and whether they are distinctly regulated. Based on the so far available experimental evidence, lamin A appears to be the most regulated A-type isoform during development, aging, and disease which indicates that lamin A is implicated in many different biological aspects and may have a greater repertoire of specialized functions than lamin C. The aim of this review is to point out differences between the two major LMNA splice variants and the consequences of these differences on their functions. This may guide further research and be of prime importance for the understanding of the pathogenesis of LMNA mutations.
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Abstract
Much of the work on nuclear lamins during the past 15 years has focused on mutations in LMNA (the gene for prelamin A and lamin C) that cause particular muscular dystrophy, cardiomyopathy, partial lipodystrophy, and progeroid syndromes. These disorders, often called "laminopathies," mainly affect mesenchymal tissues (e.g., striated muscle, bone, and fibrous tissue). Recently, however, a series of papers have identified important roles for nuclear lamins in the central nervous system. Studies of knockout mice uncovered a key role for B-type lamins (lamins B1 and B2) in neuronal migration in the developing brain. Also, duplications of LMNB1 (the gene for lamin B1) have been shown to cause autosome-dominant leukodystrophy. Finally, recent studies have uncovered a peculiar pattern of nuclear lamin expression in the brain. Lamin C transcripts are present at high levels in the brain, but prelamin A expression levels are very low-due to regulation of prelamin A transcripts by microRNA 9. This form of prelamin A regulation likely explains why "prelamin A diseases" such as Hutchinson-Gilford progeria syndrome spare the central nervous system. In this review, we summarize recent progress in elucidating links between nuclear lamins and neurobiology.
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Abstract
In eukaryotic cells the nuclear genome is enclosed by the nuclear envelope (NE). In metazoans, the NE breaks down in mitosis and it has been assumed that the physical barrier separating nucleoplasm and cytoplasm remains intact during the rest of the cell cycle and cell differentiation. However, recent studies suggest that nonmitotic NE remodeling plays a critical role in development, virus infection, laminopathies, and cancer. Although the mechanisms underlying these NE restructuring events are currently being defined, one common theme is activation of protein kinase C family members in the interphase nucleus to disrupt the nuclear lamina, demonstrating the importance of the lamina in maintaining nuclear integrity.
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Affiliation(s)
- Emily Hatch
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037
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35
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Abstract
The LMNA gene gives rise to at least three isoforms (lamin A, C, lamin AΔ10) as a result of normal alternative splicing, regulated by cis- and trans-acting regulatory factors, as well as the 5' and 3' untranslated regions of the gene. The two main isoforms, lamin A and C, are constitutive components of the fibrous nuclear lamina and have diverse physiological roles, ranging from mechanical nuclear membrane maintenance to gene regulation. The clinical spectrum of diseases (called 'laminopathies') caused by LMNA mutations is broad, including at least eight well-characterised phenotypes, some of which are confined to the skeletal muscles or skin, while others are multisystemic. This review discusses the different alternatively spliced isoforms of LMNA and the regulation of LMNA splicing, as well as the subgroup of mutations that affect splicing of LMNA pre-mRNA, and also seeks to bridge the mis-splicing of LMNA at transcript level and the resulting clinical phenotypes. Finally, we discuss the manipulation of LMNA splicing by splice-switching antisense oligonucleotides and its therapeutic potential for the treatment of some laminopathies.
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Affiliation(s)
- Yue-Bei Luo
- Centre for Neuromuscular and Neurological Disorders, Australian Neuro-Muscular Research Institute, University of Western Australia, Perth, Australia
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36
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Young SG, Yang SH, Davies BSJ, Jung HJ, Fong LG. Targeting protein prenylation in progeria. Sci Transl Med 2014; 5:171ps3. [PMID: 23390246 DOI: 10.1126/scitranslmed.3005229] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A clinical trial of a protein farnesyltransferase inhibitor (lonafarnib) for the treatment of Hutchinson-Gilford progeria syndrome (HGPS) was recently completed. Here, we discuss the mutation that causes HGPS, the rationale for inhibiting protein farnesyltransferase, the potential limitations of this therapeutic approach, and new potential strategies for treating the disease.
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Affiliation(s)
- Stephen G Young
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA. sgyoung@mednet
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37
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Abstract
Lamins A and C, encoded by LMNA, are constituent of the nuclear lamina, a meshwork of proteins underneath the nuclear envelope first described as scaffolding proteins of the nucleus. Since the discovery of LMNA mutations in highly heterogeneous human disorders (including cardiac and muscular dystrophies, lipodystrophies and progeria), the number of functions described for lamin A/C has expanded. Lamin A/C is notably involved in the regulation of chromatin structure and gene transcription, and in the resistance of cells to mechanical stress. This review focuses on studies performed on knock-out and knock-in Lmna mouse models, which have led to decipher some of the lamin A/C functions in striated muscles and to the first preclinical trials of pharmaceutical therapies.
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Abstract
In eukaryotes, the function of the cell's nucleus has primarily been considered to be the repository for the organism's genome. However, this rather simplistic view is undergoing a major shift, as it is increasingly apparent that the nucleus has functions extending beyond being a mere genome container. Recent findings have revealed that the structural composition of the nucleus changes during development and that many of these components exhibit cell- and tissue-specific differences. Increasing evidence is pointing to the nucleus being integral to the function of the interphase cytoskeleton, with changes to nuclear structural proteins having ramifications affecting cytoskeletal organization and the cell's interactions with the extracellular environment. Many of these functions originate at the nuclear periphery, comprising the nuclear envelope (NE) and underlying lamina. Together, they may act as a "hub" in integrating cellular functions including chromatin organization, transcriptional regulation, mechanosignaling, cytoskeletal organization, and signaling pathways. Interest in such an integral role has been largely stimulated by the discovery that many diseases and anomalies are caused by defects in proteins of the NE/lamina, the nuclear envelopathies, many of which, though rare, are providing insights into their more common variants that are some of the major issues of the twenty-first century public health. Here, we review the contributions that mouse mutants have made to our current understanding of the NE/lamina, their respective roles in disease and the use of mice in developing potential therapies for treating the diseases.
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Jung HJ, Tu Y, Yang SH, Tatar A, Nobumori C, Wu D, Young SG, Fong LG. New Lmna knock-in mice provide a molecular mechanism for the 'segmental aging' in Hutchinson-Gilford progeria syndrome. Hum Mol Genet 2013; 23:1506-15. [PMID: 24203701 DOI: 10.1093/hmg/ddt537] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lamins A and C (products of the LMNA gene) are found in roughly equal amounts in peripheral tissues, but the brain produces mainly lamin C and little lamin A. In HeLa cells and fibroblasts, the expression of prelamin A (the precursor to lamin A) can be reduced by miR-9, but the relevance of those cell culture studies to lamin A regulation in the brain was unclear. To address this issue, we created two new Lmna knock-in alleles, one (Lmna(PLAO-5NT)) with a 5-bp mutation in a predicted miR-9 binding site in prelamin A's 3' UTR, and a second (Lmna(PLAO-UTR)) in which prelamin A's 3' UTR was replaced with lamin C's 3' UTR. Neither allele had significant effects on lamin A levels in peripheral tissues; however, both substantially increased prelamin A transcript levels and lamin A protein levels in the cerebral cortex and the cerebellum. The increase in lamin A expression in the brain was more pronounced with the Lmna(PLAO-UTR) allele than with the Lmna(PLAO-5NT) allele. With both alleles, the increased expression of prelamin A transcripts and lamin A protein was greater in the cerebral cortex than in the cerebellum. Our studies demonstrate the in vivo importance of prelamin A's 3' UTR and its miR-9 binding site in regulating lamin A expression in the brain. The reduced expression of prelamin A in the brain likely explains why children with Hutchinson-Gilford progeria syndrome (a progeroid syndrome caused by a mutant form of prelamin A) are spared from neurodegenerative disease.
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40
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Jung HJ, Nobumori C, Goulbourne CN, Tu Y, Lee JM, Tatar A, Wu D, Yoshinaga Y, de Jong PJ, Coffinier C, Fong LG, Young SG. Farnesylation of lamin B1 is important for retention of nuclear chromatin during neuronal migration. Proc Natl Acad Sci U S A 2013; 110:E1923-32. [PMID: 23650370 PMCID: PMC3666708 DOI: 10.1073/pnas.1303916110] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of protein farnesylation in lamin A biogenesis and the pathogenesis of progeria has been studied in considerable detail, but the importance of farnesylation for the B-type lamins, lamin B1 and lamin B2, has received little attention. Lamins B1 and B2 are expressed in nearly every cell type from the earliest stages of development, and they have been implicated in a variety of functions within the cell nucleus. To assess the importance of protein farnesylation for B-type lamins, we created knock-in mice expressing nonfarnesylated versions of lamin B1 and lamin B2. Mice expressing nonfarnesylated lamin B2 developed normally and were free of disease. In contrast, mice expressing nonfarnesylated lamin B1 died soon after birth, with severe neurodevelopmental defects and striking nuclear abnormalities in neurons. The nuclear lamina in migrating neurons was pulled away from the chromatin so that the chromatin was left "naked" (free from the nuclear lamina). Thus, farnesylation of lamin B1--but not lamin B2--is crucial for brain development and for retaining chromatin within the bounds of the nuclear lamina during neuronal migration.
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Affiliation(s)
| | | | | | | | | | | | | | - Yuko Yoshinaga
- Children’s Hospital Oakland Research Institute, Oakland, CA 94609
| | | | | | | | - Stephen G. Young
- Molecular Biology Institute
- Department of Medicine, and
- Department of Human Genetics, University of California, Los Angeles, CA 90095; and
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41
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Liu B, Yip RK, Zhou Z. Chromatin remodeling, DNA damage repair and aging. Curr Genomics 2013; 13:533-47. [PMID: 23633913 PMCID: PMC3468886 DOI: 10.2174/138920212803251373] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 06/19/2012] [Accepted: 07/25/2012] [Indexed: 01/26/2023] Open
Abstract
Cells are constantly exposed to a variety of environmental and endogenous conditions causing DNA damage, which is detected and repaired by conserved DNA repair pathways to maintain genomic integrity. Chromatin remodeling is critical in this process, as the organization of eukaryotic DNA into compact chromatin presents a natural barrier to all DNA-related events. Studies on human premature aging syndromes together with normal aging have suggested that accumulated damages might lead to exhaustion of resources that are required for physiological functions and thus accelerate aging. In this manuscript, combining the present understandings and latest findings, we focus mainly on discussing the role of chromatin remodeling in the repair of DNA double-strand breaks (DSBs) and regulation of aging.
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Affiliation(s)
- Baohua Liu
- Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China ; Department of Biochemistry, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong
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42
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Bertacchini J, Beretti F, Cenni V, Guida M, Gibellini F, Mediani L, Marin O, Maraldi NM, de Pol A, Lattanzi G, Cocco L, Marmiroli S. The protein kinase Akt/PKB regulates both prelamin A degradation and Lmna gene expression. FASEB J 2013; 27:2145-55. [PMID: 23430973 DOI: 10.1096/fj.12-218214] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The serine/threonine kinase Akt/PKB is a major signaling hub integrating metabolic, survival, growth, and cell cycle regulatory signals. The definition of the phospho-motif cipher driving phosphorylation by Akt led to the identification of hundreds of putative substrates, and it is therefore pivotal to identify those whose phosphorylation by Akt is of consequence to biological processes. The Lmna gene products lamin A/C and the lamin A precursor prelamin A are type V intermediate filament proteins forming a filamentous meshwork, the lamina, underneath the inner nuclear membrane, for nuclear envelope structures organization and interphase chromatin anchoring. In our previous work, we reported that A-type lamins are phosphorylated by Akt at S301 and S404 in physiological conditions and are therefore bona fide substrates of Akt. We report here that Akt phosphorylation at S404 targets the precursor prelamin A for degradation. We further demonstrate that Akt also regulates Lmna transcription. Our study unveils a previously unknown function of Akt in the control of prelamin A stability and expression. Moreover, given the large number of diseases related to prelamin A, our findings represent a further important step bridging basic A-type lamin physiology to therapeutic approaches for lamin A-linked disorders.
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Affiliation(s)
- Jessika Bertacchini
- Cellular Signaling Laboratory, Department of Surgery, Medicine, Dentistry, and Morphology, University of Modena and Reggio Emilia, Modena, Italy
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Zwerger M, Jaalouk DE, Lombardi ML, Isermann P, Mauermann M, Dialynas G, Herrmann H, Wallrath LL, Lammerding J. Myopathic lamin mutations impair nuclear stability in cells and tissue and disrupt nucleo-cytoskeletal coupling. Hum Mol Genet 2013; 22:2335-49. [PMID: 23427149 DOI: 10.1093/hmg/ddt079] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Lamins are intermediate filament proteins that assemble into a meshwork underneath the inner nuclear membrane, the nuclear lamina. Mutations in the LMNA gene, encoding lamins A and C, cause a variety of diseases collectively called laminopathies. The disease mechanism for these diverse conditions is not well understood. Since lamins A and C are fundamental determinants of nuclear structure and stability, we tested whether defects in nuclear mechanics could contribute to the disease development, especially in laminopathies affecting mechanically stressed tissue such as muscle. Using skin fibroblasts from laminopathy patients and lamin A/C-deficient mouse embryonic fibroblasts stably expressing a broad panel of laminopathic lamin A mutations, we found that several mutations associated with muscular dystrophy and dilated cardiomyopathy resulted in more deformable nuclei; in contrast, lamin mutants responsible for diseases without muscular phenotypes did not alter nuclear deformability. We confirmed our results in intact muscle tissue, demonstrating that nuclei of transgenic Drosophila melanogaster muscle expressing myopathic lamin mutations deformed more under applied strain than controls. In vivo and in vitro studies indicated that the loss of nuclear stiffness resulted from impaired assembly of mutant lamins into the nuclear lamina. Although only a subset of lamin mutations associated with muscular diseases caused increased nuclear deformability, almost all mutations tested had defects in force transmission between the nucleus and cytoskeleton. In conclusion, our results indicate that although defective nuclear stability may play a role in the development of muscle diseases, other factors, such as impaired nucleo-cytoskeletal coupling, likely contribute to the muscle phenotype.
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Affiliation(s)
- Monika Zwerger
- Department of Medicine, Brigham and Women's Hospital/Harvard Medical School, Boston, MA 02115, USA
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Zhang H, Kieckhaefer JE, Cao K. Mouse models of laminopathies. Aging Cell 2013; 12:2-10. [PMID: 23095062 DOI: 10.1111/acel.12021] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2012] [Indexed: 01/02/2023] Open
Abstract
The A- and B-type lamins are nuclear intermediate filament proteins in eukaryotic cells with a broad range of functions, including the organization of nuclear architecture and interaction with proteins in many cellular functions. Over 180 disease-causing mutations, termed 'laminopathies,' have been mapped throughout LMNA, the gene for A-type lamins in humans. Laminopathies can range from muscular dystrophies, cardiomyopathy, to Hutchinson-Gilford progeria syndrome. A number of mouse lines carrying some of the same mutations as those resulting in human diseases have been established. These LMNA-related mouse models have provided valuable insights into the functions of lamin A biogenesis and the roles of individual A-type lamins during tissue development. This review groups these LMNA-related mouse models into three categories: null mutants, point mutants, and progeroid mutants. We compare their phenotypes and discuss their potential implications in laminopathies and aging.
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Affiliation(s)
- Haoyue Zhang
- Department of Cell Biology and Molecular Genetics; University of Maryland; College Park; MD 20742; USA
| | - Julia E. Kieckhaefer
- Department of Cell Biology and Molecular Genetics; University of Maryland; College Park; MD 20742; USA
| | - Kan Cao
- Department of Cell Biology and Molecular Genetics; University of Maryland; College Park; MD 20742; USA
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Liu B, Wang Z, Zhang L, Ghosh S, Zheng H, Zhou Z. Depleting the methyltransferase Suv39h1 improves DNA repair and extends lifespan in a progeria mouse model. Nat Commun 2013; 4:1868. [PMID: 23695662 PMCID: PMC3674265 DOI: 10.1038/ncomms2885] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 04/17/2013] [Indexed: 12/26/2022] Open
Abstract
A de novo G608G mutation in LMNA gene leads to Hutchinson-Gilford progeria syndrome. Mice lacking the prelamin A-processing metalloprotease, Zmpste24, recapitulate many of the progeroid features of Hutchinson-Gilford progeria syndrome. Here we show that A-type lamins interact with SUV39H1, and prelamin A/progerin exhibits enhanced binding capacity to SUV39H1, protecting it from proteasomal degradation and, consequently, increasing H3K9me3 levels. Depletion of Suv39h1 reduces H3K9me3 levels, restores DNA repair capacity and delays senescence in progeroid cells. Remarkably, loss of Suv39h1 in Zmpste24(-/-) mice delays body weight loss, increases bone mineral density and extends lifespan by ∼60%. Thus, increased H3K9me3 levels, possibly mediated by enhanced Suv39h1 stability in the presence of prelamin A/progerin, compromise genome maintenance, which in turn contributes to accelerated senescence in laminopathy-based premature aging. Our study provides an explanation for epigenetic alterations in Hutchinson-Gilford progeria syndrome and a potential strategy for intervention by targeting SUV39H1-mediated heterochromatin remodelling.
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Affiliation(s)
- Baohua Liu
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong; Hong Kong
- Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China
| | - Zimei Wang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong; Hong Kong
| | - Le Zhang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong; Hong Kong
| | - Shrestha Ghosh
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong; Hong Kong
| | - Huiling Zheng
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong; Hong Kong
- Institute of Aging Research, Guangdong Medical College, Dong-guan 523808, China
| | - Zhongjun Zhou
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong; Hong Kong
- Shenzhen Institute of Research and Innovation, The University of Hong Kong, Shenzhen, China
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Jung HJ, Lee JM, Yang SH, Young SG, Fong LG. Nuclear lamins in the brain - new insights into function and regulation. Mol Neurobiol 2012; 47:290-301. [PMID: 23065386 DOI: 10.1007/s12035-012-8350-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 09/12/2012] [Indexed: 11/28/2022]
Abstract
The nuclear lamina is an intermediate filament meshwork composed largely of four nuclear lamins - lamins A and C (A-type lamins) and lamins B1 and B2 (B-type lamins). Located immediately adjacent to the inner nuclear membrane, the nuclear lamina provides a structural scaffolding for the cell nucleus. It also interacts with both nuclear membrane proteins and the chromatin and is thought to participate in many important functions within the cell nucleus. Defects in A-type lamins cause cardiomyopathy, muscular dystrophy, peripheral neuropathy, lipodystrophy, and progeroid disorders. In contrast, the only bona fide link between the B-type lamins and human disease is a rare demyelinating disease of the central nervous system - adult-onset autosomal-dominant leukoencephalopathy, caused by a duplication of the gene for lamin B1. However, this leukoencephalopathy is not the only association between the brain and B-type nuclear lamins. Studies of conventional and tissue-specific knockout mice have demonstrated that B-type lamins play essential roles in neuronal migration in the developing brain and in neuronal survival. The importance of A-type lamin expression in the brain is unclear, but it is intriguing that the adult brain preferentially expresses lamin C rather than lamin A, very likely due to microRNA-mediated removal of prelamin A transcripts. Here, we review recent studies on nuclear lamins, focusing on the function and regulation of the nuclear lamins in the central nervous system.
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Affiliation(s)
- Hea-Jin Jung
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
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Novelli G, D'Apice MR. Protein farnesylation and disease. J Inherit Metab Dis 2012; 35:917-26. [PMID: 22307208 DOI: 10.1007/s10545-011-9445-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 12/16/2011] [Accepted: 12/22/2011] [Indexed: 12/19/2022]
Abstract
Prenylation consists of the addition of an isoprenoid group to a cysteine residue located near the carboxyl terminal of a protein. This enzymatic posttranslational modification is important for the maturation and processing of proteins. Both processes are necessary to mediate protein-protein and membrane-protein associations, in addition to regulating the localisation and function of proteins. The severe phenotype of animals deficient in enzymes involved in both prenylation and maturation highlights the significance of these processes. Moreover, alterations in the genes coding for isoprenylated proteins or enzymes that are involved in both prenylation and maturation processes have been found to be the basis of severe human diseases, such as cancer, neurodegenerative disorders, retinitis pigmentosa, and premature ageing syndromes. Recent studies on isoprenylation and postprenylation processing in pathological conditions have unveiled surprising aspects of these modifications and their roles in different cellular pathways. The identification of these enzymes as therapeutic targets has led researchers to validate their effects in vitro and in vivo as antitumour or antiageing agents. This review attempts to summarise the basic aspects of protein isoprenylation and postprenylation, integrating our data with that observed in other studies to provide a comprehensive scenario of progeroid syndromes and the therapeutic avenues.
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Affiliation(s)
- Giuseppe Novelli
- Department of Biopathology and Diagnostic Imaging, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
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Butin-Israeli V, Adam SA, Goldman AE, Goldman RD. Nuclear lamin functions and disease. Trends Genet 2012; 28:464-71. [PMID: 22795640 DOI: 10.1016/j.tig.2012.06.001] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 05/25/2012] [Accepted: 06/13/2012] [Indexed: 12/26/2022]
Abstract
Recent studies have shown that premature cellular senescence and normal organ development and function depend on the type V intermediate filament proteins, the lamins, which are major structural proteins of the nucleus. This review presents an up-to-date summary of the literature describing new findings on lamin functions in various cellular processes and emphasizes the relationship between the lamins and devastating diseases ranging from premature aging to cancer. Recent insights into the structure and function of the A- and B- type lamins in normal cells and their dysfunctions in diseased cells are providing novel targets for the development of new diagnostic procedures and disease intervention. We summarize these recent findings, focusing on data from mice and humans, and highlight the expanding knowledge of these proteins in both healthy and diseased cells.
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Affiliation(s)
- Veronika Butin-Israeli
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA.
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Wang Y, Ostlund C, Worman HJ. Blocking protein farnesylation improves nuclear shape abnormalities in keratinocytes of mice expressing the prelamin A variant in Hutchinson-Gilford progeria syndrome. Nucleus 2012; 1:432-9. [PMID: 21326826 DOI: 10.4161/nucl.1.5.12972] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 07/09/2010] [Accepted: 07/13/2010] [Indexed: 01/01/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is an accelerated aging disorder caused by mutations in LMNA leading to expression of a truncated prelamin A variant termed progerin. Whereas a farnesylated polypeptide is normally removed from the carboxyl-terminus of prelamin A during endoproteolytic processing to lamin A, progerin lacks the cleavage site and remains farnesylated. Cultured cells from human subjects with HGPS and genetically modified mice expressing progerin have nuclear morphological abnormalities, which are reversed by inhibitors of protein farnesylation. In addition, treatment with protein farnesyltransferase inhibitors improves whole animal phenotypes in mouse models of HGPS. However, improvement in nuclear morphology in tissues after treatment of animals has not been demonstrated. We therefore treated transgenic mice that express progerin in epidermis with the protein farnesyltransferase inhibitor FTI-276 or a combination of pravastatin and zoledronate to determine if they reversed nuclear morphological abnormalities in tissue. Immunofluorescence microscopy and "blinded" electron microscopic analysis demonstrated that systemic administration of FTI-276 or pravastatin plus zoledronate significantly improved nuclear morphological abnormalities in keratinocytes of transgenic mice. These results show that pharmacological blockade of protein prenylation reverses nuclear morphological abnormalities that occur in HGPS in vivo. They further suggest that skin biopsy may be useful to determine if protein farnesylation inhibitors are exerting effects in subjects with HGPS in clinical trials.
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Affiliation(s)
- Yuexia Wang
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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