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Gu H, Pan Y, Xiao H, Zhao L, Tang Y, Ge W. Knockdown of LAP2α inhibits adipogenesis of human adipose-derived stem cells and ameliorates high-fat diet-induced obesity. FASEB J 2024; 38:e23664. [PMID: 38775797 DOI: 10.1096/fj.202302435rr] [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: 11/27/2023] [Revised: 04/17/2024] [Accepted: 04/29/2024] [Indexed: 05/30/2024]
Abstract
Adipogenesis, a pivotal cellular process involving the differentiation of mesenchymal stem cells (MSCs) to mature adipocytes, plays a significant role in various physiological functions. Dysregulation of adipogenesis is implicated in conditions such as obesity. However, the complete molecular understanding of adipogenesis remains elusive. This study aimed to uncover the novel role of lamina-associated polypeptide 2 alpha (LAP2α) in human adipose-derived stem cells (hASCs) adipogenesis and its impact on high-fat diet (HFD)-induced obesity and associated metabolic disturbances. LAP2α expression was assessed during the adipogenic differentiation of hASCs using RT-qPCR and western blotting. The functional role of LAP2α in adipogenesis was explored both in vitro and in vivo through loss- and gain-of-function studies. Moreover, mice with HFD-induced obesity received lentivirus injection to assess the effect of LAP2α knockdown on fat accumulation. Molecular mechanisms underlying LAP2α in adipogenic differentiation were investigated using RT-qPCR, Western blotting, immunofluorescence staining, and Oil Red O staining. LAP2α expression was upregulated during hASCs adipogenic differentiation. LAP2α knockdown hindered adipogenesis, while LAP2α overexpression promoted adipogenic differentiation. Notably, LAP2α deficiency resisted HFD-induced obesity, improved glucose intolerance, mitigated insulin resistance, and prevented fatty liver development. Mechanistically, LAP2α knockdown attenuated signal transducer and activator of transcription 3 (STAT3) activation by reducing the protein level of phosphorylated STAT3. A STAT3 activator (Colivelin) counteracted the negative impact of LAP2α deficiency on hASCs adipogenic differentiation. Taken together, our current study established LAP2α as a crucial regulator of hASCs adipogenic differentiation, unveiling a new therapeutic target for obesity prevention.
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Affiliation(s)
- Hang Gu
- Department of General Dentistry II, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, P.R. China
| | - Yuan Pan
- Department of General Dentistry II, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, P.R. China
| | - Han Xiao
- Department of General Dentistry II, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, P.R. China
| | - Lijun Zhao
- Department of General Dentistry II, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, P.R. China
| | - Yiman Tang
- Fourth Clinical Division, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, P.R. China
| | - Wenshu Ge
- Department of General Dentistry II, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, P.R. China
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Rose M, Burgess JT, Cheong CM, Adams MN, Shahrouzi P, O’Byrne KJ, Richard DJ, Bolderson E. The expression and role of the Lem-D proteins Ankle2, Emerin, Lemd2, and TMPO in triple-negative breast cancer cell growth. Front Oncol 2024; 14:1222698. [PMID: 38720803 PMCID: PMC11076778 DOI: 10.3389/fonc.2024.1222698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 02/28/2024] [Indexed: 05/12/2024] Open
Abstract
Background Triple-negative breast cancer (TNBC) is a sub-classification of breast carcinomas, which leads to poor survival outcomes for patients. TNBCs do not possess the hormone receptors that are frequently targeted as a therapeutic in other cancer subtypes and, therefore, chemotherapy remains the standard treatment for TNBC. Nuclear envelope proteins are frequently dysregulated in cancer cells, supporting their potential as novel cancer therapy targets. The Lem-domain (Lem-D) (LAP2, Emerin, MAN1 domain, and Lem-D) proteins are a family of inner nuclear membrane proteins, which share a ~45-residue Lem-D. The Lem-D proteins, including Ankle2, Lemd2, TMPO, and Emerin, have been shown to be associated with many of the hallmarks of cancer. This study aimed to define the association between the Lem-D proteins and TNBC and determine whether these proteins could be promising therapeutic targets. Methods GENT2, TCGA, and KM plotter were utilized to investigate the expression and prognostic implications of several Lem-D proteins: Ankle2, TMPO, Emerin, and Lemd2 in publicly available breast cancer patient data. Immunoblotting and immunofluorescent analysis of immortalized non-cancerous breast cells and a panel of TNBC cells were utilized to establish whether protein expression of the Lem-D proteins was significantly altered in TNBC. SiRNA was used to decrease individual Lem-D protein expression, and functional assays, including proliferation assays and apoptosis assays, were conducted. Results The Lem-D proteins were generally overexpressed in TNBC patient samples at the mRNA level and showed variable expression at the protein level in TNBC cell lysates. Similarly, protein levels were generally negatively correlated with patient survival outcomes. siRNA-mediated depletion of the individual Lem-D proteins in TNBC cells induced aberrant nuclear morphology, decreased proliferation, and induced cell death. However, minimal effects on nuclear morphology or cell viability were observed following Lem-D depletion in non-cancerous MCF10A cells. Conclusion There is evidence to suggest that Ankle2, TMPO, Emerin, and Lemd2 expressions are correlated with breast cancer patient outcomes, but larger patient sample numbers are required to confirm this. siRNA-mediated depletion of these proteins was shown to specifically impair TNBC cell growth, suggesting that the Lem-D proteins may be a specific anti-cancer target.
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Affiliation(s)
- Maddison Rose
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Joshua T. Burgess
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Chee Man Cheong
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Mark N. Adams
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Parastoo Shahrouzi
- Department of Medical Genetics, Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Kenneth J. O’Byrne
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Cancer Services, Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Derek J. Richard
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Emma Bolderson
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
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Escudeiro-Lopes S, Filimonenko VV, Jarolimová L, Hozák P. Lamin A/C and PI(4,5)P2-A Novel Complex in the Cell Nucleus. Cells 2024; 13:399. [PMID: 38474363 DOI: 10.3390/cells13050399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/06/2024] [Accepted: 02/10/2024] [Indexed: 03/14/2024] Open
Abstract
Lamins, the nuclear intermediate filaments, are important regulators of nuclear structural integrity as well as nuclear functional processes such as DNA transcription, replication and repair, and epigenetic regulations. A portion of phosphorylated lamin A/C localizes to the nuclear interior in interphase, forming a lamin A/C pool with specific properties and distinct functions. Nucleoplasmic lamin A/C molecular functions are mainly dependent on its binding partners; therefore, revealing new interactions could give us new clues on the lamin A/C mechanism of action. In the present study, we show that lamin A/C interacts with nuclear phosphoinositides (PIPs), and with nuclear myosin I (NM1). Both NM1 and nuclear PIPs have been previously reported as important regulators of gene expression and DNA damage/repair. Furthermore, phosphorylated lamin A/C forms a complex with NM1 in a phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2)-dependent manner in the nuclear interior. Taken together, our study reveals a previously unidentified interaction between phosphorylated lamin A/C, NM1, and PI(4,5)P2 and suggests new possible ways of nucleoplasmic lamin A/C regulation, function, and importance for the formation of functional nuclear microdomains.
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Affiliation(s)
- Sara Escudeiro-Lopes
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Vlada V Filimonenko
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
- Electron Microscopy Core Facility, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Lenka Jarolimová
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Pavel Hozák
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
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Keuper K, Bartek J, Maya-Mendoza A. The nexus of nuclear envelope dynamics, circular economy and cancer cell pathophysiology. Eur J Cell Biol 2024; 103:151394. [PMID: 38340500 DOI: 10.1016/j.ejcb.2024.151394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024] Open
Abstract
The nuclear envelope (NE) is a critical component in maintaining the function and structure of the eukaryotic nucleus. The NE and lamina are disassembled during each cell cycle to enable an open mitosis. Nuclear architecture construction and deconstruction is a prime example of a circular economy, as it fulfills a highly efficient recycling program bound to continuous assessment of the quality and functionality of the building blocks. Alterations in the nuclear dynamics and lamina structure have emerged as important contributors to both oncogenic transformation and cancer progression. However, the knowledge of the NE breakdown and reassembly is still limited to a fraction of participating proteins and complexes. As cancer cells contain highly diverse nuclei in terms of DNA content, but also in terms of nuclear number, size, and shape, it is of great interest to understand the intricate relationship between these nuclear features in cancer cell pathophysiology. In this review, we provide insights into how those NE dynamics are regulated, and how lamina destabilization processes may alter the NE circular economy. Moreover, we expand the knowledge of the lamina-associated domain region by using strategic algorithms, including Artificial Intelligence, to infer protein associations, assess their function and location, and predict cancer-type specificity with implications for the future of cancer diagnosis, prognosis and treatment. Using this approach we identified NUP98 and MECP2 as potential proteins that exhibit upregulation in Acute Myeloid Leukemia (LAML) patients with implications for early diagnosis.
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Affiliation(s)
- Kristina Keuper
- DNA Replication and Cancer Group, Danish Cancer Institute, Copenhagen, Denmark; Genome Integrity Group, Danish Cancer Institute, Copenhagen, Denmark
| | - Jiri Bartek
- Genome Integrity Group, Danish Cancer Institute, Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SciLifeLab, Stockholm, Sweden
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Buxboim A, Kronenberg-Tenga R, Salajkova S, Avidan N, Shahak H, Thurston A, Medalia O. Scaffold, mechanics and functions of nuclear lamins. FEBS Lett 2023; 597:2791-2805. [PMID: 37813648 DOI: 10.1002/1873-3468.14750] [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: 06/16/2023] [Revised: 09/05/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Nuclear lamins are type-V intermediate filaments that are involved in many nuclear processes. In mammals, A- and B-type lamins assemble into separate physical meshwork underneath the inner nuclear membrane, the nuclear lamina, with some residual fraction localized within the nucleoplasm. Lamins are the major part of the nucleoskeleton, providing mechanical strength and flexibility to protect the genome and allow nuclear deformability, while also contributing to gene regulation via interactions with chromatin. While lamins are the evolutionary ancestors of all intermediate filament family proteins, their ultimate filamentous assembly is markedly different from their cytoplasmic counterparts. Interestingly, hundreds of genetic mutations in the lamina proteins have been causally linked with a broad range of human pathologies, termed laminopathies. These include muscular, neurological and metabolic disorders, as well as premature aging diseases. Recent technological advances have contributed to resolving the filamentous structure of lamins and the corresponding lamina organization. In this review, we revisit the multiscale lamin organization and discuss its implications on nuclear mechanics and chromatin organization within lamina-associated domains.
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Affiliation(s)
- Amnon Buxboim
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | | | - Sarka Salajkova
- Department of Biochemistry, University of Zurich, Switzerland
| | - Nili Avidan
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Hen Shahak
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Alice Thurston
- Department of Biochemistry, University of Zurich, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Switzerland
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Buchwalter A. Intermediate, but not average: The unusual lives of the nuclear lamin proteins. Curr Opin Cell Biol 2023; 84:102220. [PMID: 37619289 DOI: 10.1016/j.ceb.2023.102220] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/26/2023]
Abstract
The nuclear lamins are polymeric intermediate filament proteins that scaffold the nucleus and organize the genome in nearly all eukaryotic cells. This review focuses on the dynamic regulation of lamin filaments through their biogenesis, assembly, disassembly, and degradation. The lamins are unusually long-lived proteins under homeostatic conditions, but their turnover can be induced in select contexts that are highlighted in this review. Finally, we discuss recent investigations into the influence of laminopathy-linked mutations on the assembly, folding, and stability of the nuclear lamins.
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Affiliation(s)
- Abigail Buchwalter
- Cardiovascular Research Institute and Department of Physiology, University of California, San Francisco, San Francisco, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA.
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Upadhyay KK, Choi EYK, Foisner R, Omary MB, Brady GF. Hepatocyte-specific loss of LAP2α protects against diet-induced hepatic steatosis, steatohepatitis, and fibrosis in male mice. Am J Physiol Gastrointest Liver Physiol 2023; 325:G184-G195. [PMID: 37366543 PMCID: PMC10396226 DOI: 10.1152/ajpgi.00214.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 05/24/2023] [Accepted: 06/18/2023] [Indexed: 06/28/2023]
Abstract
There is increasing evidence for the importance of the nuclear envelope in lipid metabolism, nonalcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH). Human mutations in LMNA, encoding A-type nuclear lamins, cause early-onset insulin resistance and NASH, while hepatocyte-specific deletion of Lmna predisposes to NASH with fibrosis in male mice. Given that variants in the gene encoding LAP2α, a nuclear protein that regulates lamin A/C, were previously identified in patients with NAFLD, we sought to determine the role of LAP2α in NAFLD using a mouse genetic model. Hepatocyte-specific Lap2α-knockout (Lap2α(ΔHep)) mice and littermate controls were fed normal chow or high-fat diet (HFD) for 8 wk or 6 mo. Unexpectedly, male Lap2α(ΔHep) mice showed no increase in hepatic steatosis or NASH compared with controls. Rather, Lap2α(ΔHep) mice demonstrated reduced hepatic steatosis, with decreased NASH and fibrosis after long-term HFD. Accordingly, pro-steatotic genes including Cidea, Mogat1, and Cd36 were downregulated in Lap2α(ΔHep) mice, along with concomitant decreases in expression of pro-inflammatory and pro-fibrotic genes. These data indicate that hepatocyte-specific Lap2α deletion protects against hepatic steatosis and NASH in mice and raise the possibility that LAP2α could become a potential therapeutic target in human NASH.NEW & NOTEWORTHY The nuclear envelope and lamina regulate lipid metabolism and susceptibility to nonalcoholic steatohepatitis (NASH), but the role of the nuclear lamin-binding protein LAP2α in NASH has not been explored. Our data demonstrate that hepatocyte-specific loss of LAP2α protects against diet-induced hepatic steatosis, NASH, and fibrosis in male mice, with downregulation of pro-steatotic, pro-inflammatory, and pro-fibrotic lamin-regulated genes. These findings suggest that targeting LAP2α could have future potential as a novel therapeutic avenue in NASH.
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Affiliation(s)
- Kapil K Upadhyay
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States
| | - Eun-Young K Choi
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States
| | - Roland Foisner
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter Campus, Vienna, Austria
| | - M Bishr Omary
- Robert Wood Johnson Medical School and the Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey, United States
| | - Graham F Brady
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States
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Zhang B, Powers JD, McCulloch AD, Chi NC. Nuclear mechanosignaling in striated muscle diseases. Front Physiol 2023; 14:1126111. [PMID: 36960155 PMCID: PMC10027932 DOI: 10.3389/fphys.2023.1126111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/22/2023] [Indexed: 03/09/2023] Open
Abstract
Mechanosignaling describes processes by which biomechanical stimuli are transduced into cellular responses. External biophysical forces can be transmitted via structural protein networks that span from the cellular membrane to the cytoskeleton and the nucleus, where they can regulate gene expression through a series of biomechanical and/or biochemical mechanosensitive mechanisms, including chromatin remodeling, translocation of transcriptional regulators, and epigenetic factors. Striated muscle cells, including cardiac and skeletal muscle myocytes, utilize these nuclear mechanosignaling mechanisms to respond to changes in their intracellular and extracellular mechanical environment and mediate gene expression and cell remodeling. In this brief review, we highlight and discuss recent experimental work focused on the pathway of biomechanical stimulus propagation at the nucleus-cytoskeleton interface of striated muscles, and the mechanisms by which these pathways regulate gene regulation, muscle structure, and function. Furthermore, we discuss nuclear protein mutations that affect mechanosignaling function in human and animal models of cardiomyopathy. Furthermore, current open questions and future challenges in investigating striated muscle nuclear mechanosignaling are further discussed.
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Affiliation(s)
- Bo Zhang
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
| | - Joseph D. Powers
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
| | - Andrew D. McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
- Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA, United States
| | - Neil C. Chi
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States
- Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA, United States
- Department of Medicine, Division of Cardiovascular Medicine, University of California San Diego, La Jolla, CA, United States
- Institute of Genomic Medicine, University of California San Diego, La Jolla, CA, United States
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Vadrot N, Ader F, Moulin M, Merlant M, Chapon F, Gandjbakhch E, Labombarda F, Maragnes P, Réant P, Rooryck C, Probst V, Donal E, Richard P, Ferreiro A, Buendia B. Abnormal Cellular Phenotypes Induced by Three TMPO/LAP2 Variants Identified in Men with Cardiomyopathies. Cells 2023; 12:337. [PMID: 36672271 PMCID: PMC9857342 DOI: 10.3390/cells12020337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
A single missense variant of the TMPO/LAP2α gene, encoding LAP2 proteins, has been associated with cardiomyopathy in two brothers. To further evaluate its role in cardiac muscle, we included TMPO in our cardiomyopathy diagnostic gene panel. A screening of ~5000 patients revealed three novel rare TMPO heterozygous variants in six males diagnosed with hypertrophic or dilated cardiomypathy. We identified in different cellular models that (1) the frameshift variant LAP2α p.(Gly395Glufs*11) induced haploinsufficiency, impeding cell proliferation and/or producing a truncated protein mislocalized in the cytoplasm; (2) the C-ter missense variant LAP2α p.(Ala240Thr) led to a reduced proximity events between LAP2α and the nucleosome binding protein HMGN5; and (3) the LEM-domain missense variant p.(Leu124Phe) decreased both associations of LAP2α/β with the chromatin-associated protein BAF and inhibition of the E2F1 transcription factor activity which is known to be dependent on Rb, partner of LAP2α. Additionally, the LAP2α expression was lower in the left ventricles of male mice compared to females. In conclusion, our study reveals distinct altered properties of LAP2 induced by these TMPO/LAP2 variants, leading to altered cell proliferation, chromatin structure or gene expression-regulation pathways, and suggests a potential sex-dependent role of LAP2 in myocardial function and disease.
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Affiliation(s)
- Nathalie Vadrot
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Flavie Ader
- APHP—Sorbonne Université, Unité Fonctionnelle de Cardiogénétique et Myogénétique Moléculaire, Service de Biochimie Métabolique, HU Pitié Salpêtrière—Charles Foix, F-75013 Paris, France
- INSERM, UMR_S 1166, Sorbonne Université, F-75005 Paris, France
- Faculté de Pharmacie Paris Descartes, Département 3, Université Paris Cité, F-75006 Paris, France
| | - Maryline Moulin
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Marie Merlant
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | | | - Estelle Gandjbakhch
- INSERM, UMR_S 1166, Sorbonne Université, F-75005 Paris, France
- Département de cardiologie, APHP—Sorbonne Université, HU Pitié Salpêtrière- Charles Foix, F-75610 Paris, France
| | - Fabien Labombarda
- Service de Cardiologie, CHU de Caen, Université de Caen Normandie, F-14000 Caen, France
| | - Pascale Maragnes
- Cardiologie pédiatrique, Service de pédiatrie, CHU de Caen, F-14000 Caen, France
| | - Patricia Réant
- Service de Cardiologie, Hôpital Haut Lévêque, CHU de Bordeaux, INSERM 1045, Université de Bordeaux, F-33000 Bordeaux, France
| | - Caroline Rooryck
- Service de Génétique Médicale, CHU Bordeaux, F-33000 Bordeaux, France
| | - Vincent Probst
- Centre de référence des maladies rythmiques cardiaques, CHU de Nantes, F-44000 Nantes, France
| | - Erwan Donal
- Centre Cardio-Pneumologique, CHU de Rennes Hôpital de Pontchaillou, F-35000 Rennes, France
| | - Pascale Richard
- APHP—Sorbonne Université, Unité Fonctionnelle de Cardiogénétique et Myogénétique Moléculaire, Service de Biochimie Métabolique, HU Pitié Salpêtrière—Charles Foix, F-75013 Paris, France
- INSERM, UMR_S 1166, Sorbonne Université, F-75005 Paris, France
| | - Ana Ferreiro
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
- APHP, Centre de référence des Maladies Neuromusculaires, Institut de Myologie, Neuromyology Department, CHU Pitié Salpêtrière—Charles Foix, F-75013 Paris, France
| | - Brigitte Buendia
- Basic and Translational Myology Laboratory, Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
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Stenvall CGA, Nyström JH, Butler-Hallissey C, Jansson T, Heikkilä TRH, Adam SA, Foisner R, Goldman RD, Ridge KM, Toivola DM. Cytoplasmic keratins couple with and maintain nuclear envelope integrity in colonic epithelial cells. Mol Biol Cell 2022; 33:ar121. [PMID: 36001365 PMCID: PMC9634972 DOI: 10.1091/mbc.e20-06-0387] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Keratin intermediate filaments convey mechanical stability and protection against stress to epithelial cells. Keratins are essential for colon health, as seen in keratin 8 knockout (K8-/-) mice exhibiting a colitis phenotype. We hypothesized that keratins support the nuclear envelope and lamina in colonocytes. K8-/- colonocytes in vivo exhibit significantly decreased levels of lamins A/C, B1, and B2 in a colon-specific and cell-intrinsic manner. CRISPR/Cas9- or siRNA-mediated K8 knockdown in Caco-2 cells similarly decreased lamin levels, which recovered after reexpression of K8 following siRNA treatment. Nuclear area was not decreased, and roundness was only marginally increased in cells without K8. Down-regulation of K8 in adult K8flox/flox;Villin-CreERt2 mice following tamoxifen administration significantly decreased lamin levels at day 4 when K8 levels had reduced to 40%. K8 loss also led to reduced levels of plectin, LINC complex, and lamin-associated proteins. While keratins were not seen in the nucleoplasm without or with leptomycin B treatment, keratins were found intimately located at the nuclear envelope and complexed with SUN2 and lamin A. Furthermore, K8 loss in Caco-2 cells compromised nuclear membrane integrity basally and after shear stress. In conclusion, colonocyte K8 helps maintain nuclear envelope and lamina composition and contributes to nuclear integrity.
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Affiliation(s)
| | - Joel H. Nyström
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | - Ciarán Butler-Hallissey
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University,Turku Bioscience Centre, University of Turku, and Åbo Akademi University, and,Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, 13005 Marseille, France
| | - Theresia Jansson
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | - Taina R. H. Heikkilä
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | | | - Roland Foisner
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter Campus, 1030 Vienna, Austria
| | | | - Karen M. Ridge
- Department of Cell and Developmental Biology and,Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Diana M. Toivola
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University,InFLAMES Research Flagship Center, Åbo Akademi University, 20500 Turku, Finland,Turku Center for Disease Modeling, University of Turku, 20520 Turku, Finland,*Address correspondence to: Diana M. Toivola ()
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11
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The inner nuclear membrane protein NEMP1 supports nuclear envelope openings and enucleation of erythroblasts. PLoS Biol 2022; 20:e3001811. [PMID: 36215313 PMCID: PMC9595564 DOI: 10.1371/journal.pbio.3001811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 10/25/2022] [Accepted: 08/30/2022] [Indexed: 11/14/2022] Open
Abstract
Nuclear envelope membrane proteins (NEMPs) are a conserved family of nuclear envelope (NE) proteins that reside within the inner nuclear membrane (INM). Even though Nemp1 knockout (KO) mice are overtly normal, they display a pronounced splenomegaly. This phenotype and recent reports describing a requirement for NE openings during erythroblasts terminal maturation led us to examine a potential role for Nemp1 in erythropoiesis. Here, we report that Nemp1 KO mice show peripheral blood defects, anemia in neonates, ineffective erythropoiesis, splenomegaly, and stress erythropoiesis. The erythroid lineage of Nemp1 KO mice is overrepresented until the pronounced apoptosis of polychromatophilic erythroblasts. We show that NEMP1 localizes to the NE of erythroblasts and their progenitors. Mechanistically, we discovered that NEMP1 accumulates into aggregates that localize near or at the edge of NE openings and Nemp1 deficiency leads to a marked decrease of both NE openings and ensuing enucleation. Together, our results for the first time demonstrate that NEMP1 is essential for NE openings and erythropoietic maturation in vivo and provide the first mouse model of defective erythropoiesis directly linked to the loss of an INM protein.
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12
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Maurizi E, Merra A, Schiroli D, Ghezzi B, Macaluso C, Pellegrini G. Fluctuations in Corneal Endothelial LAP2 Expression Levels Correlate with Passage Dependent Declines in Their Cell Proliferative Activity. Int J Mol Sci 2022; 23:ijms23105859. [PMID: 35628669 PMCID: PMC9146651 DOI: 10.3390/ijms23105859] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/19/2022] [Accepted: 05/22/2022] [Indexed: 01/27/2023] Open
Abstract
The corneal endothelium is the inner corneal mono-layered epithelium, fundamental for preserving corneal hydration and transparency. However, molecular mechanisms that regulate corneal endothelial cells (CEnCs), in particular regarding their proliferative capacity, have been only partially elucidated. CEnCs are quiescent in vivo and they easily undergo endothelial to mesenchymal transition (EnMT) in vitro. This study aims to analyze CEnCs behavior and expression in vitro, either in sub-confluent growing (S) or confluent (C) CEnCs cultures. Primary rabbit and human CEnCs were cultured and used for RT-PCR, immunofluorescence or western blot analysis. These methods allowed identifying a novel molecular marker, LAP2, that is upregulated in S while downregulated in C human or rabbit CEnCs. Those results were observed for several subsequent passages in culture and this, together with the correlation between ki67 and LAP2 expression, suggested LAP2 as a novel possible indicator for culture ageing. Finally, treatment with FGF and TGFβ in rCEnCs highlighted how LAP2 can vary as the cells regulate their proliferative state. In conclusion, we have identified a novel marker for CEnCs, LAP2, that regulates its expression depending on the cells sub/confluent state and that correlates with CEnCs proliferation.
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Affiliation(s)
- Eleonora Maurizi
- Centre for Regenerative Medicine, University of Modena and Reggio Emilia, 41125 Modena, Italy;
- Correspondence:
| | - Alessia Merra
- Holostem Terapie Avanzate S.r.l., 41125 Modena, Italy;
| | - Davide Schiroli
- Transfusion Medicine Unit, Azienda USL-IRCCS, 42123 Reggio Emilia, Italy;
| | - Benedetta Ghezzi
- Dentistry Centre Lab, University of Parma, 43126 Parma, Italy; (B.G.); (C.M.)
| | - Claudio Macaluso
- Dentistry Centre Lab, University of Parma, 43126 Parma, Italy; (B.G.); (C.M.)
| | - Graziella Pellegrini
- Centre for Regenerative Medicine, University of Modena and Reggio Emilia, 41125 Modena, Italy;
- Holostem Terapie Avanzate S.r.l., 41125 Modena, Italy;
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13
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Bao K, Zhang Q, Liu S, Song N, Guo Q, Liu L, Tian S, Hao J, Zhu Y, Zhang K, Ai D, Yang J, Yao Z, Foisner R, Shi L. LAP2α preserves genome integrity through assisting RPA deposition on damaged chromatin. Genome Biol 2022; 23:64. [PMID: 35227284 PMCID: PMC8883701 DOI: 10.1186/s13059-022-02638-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 02/17/2022] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Single-stranded DNA (ssDNA) coated with replication protein A (RPA) acts as a key platform for the recruitment and exchange of genome maintenance factors in DNA damage response. Yet, how the formation of the ssDNA-RPA intermediate is regulated remains elusive. RESULTS Here, we report that the lamin-associated protein LAP2α is physically associated with RPA, and LAP2α preferentially facilitates RPA deposition on damaged chromatin via physical contacts between LAP2α and RPA1. Importantly, LAP2α-promoted RPA binding to ssDNA plays a critical role in protection of replication forks, activation of ATR, and repair of damaged DNA. We further demonstrate that the preference of LAP2α-promoted RPA loading on damaged chromatin depends on poly ADP-ribose polymerase PARP1, but not poly(ADP-ribosyl)ation. CONCLUSIONS Our study provides mechanistic insight into RPA deposition in response to DNA damage and reveals a genome protection role of LAP2α.
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Affiliation(s)
- Kaiwen Bao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Qi Zhang
- Department of Clinical Laboratory, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China
| | - Shuai Liu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Nan Song
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Qiushi Guo
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Ling Liu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Shanshan Tian
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Jihui Hao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Yi Zhu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Kai Zhang
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Ding Ai
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Jie Yang
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Zhi Yao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China
| | - Roland Foisner
- Max Perutz Laboratories, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Lei Shi
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China.
- Department of Biochemistry and Molecular Biology, Tianjin Medical University, 22 Qixiangtai Road, Tianjin, 300070, China.
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14
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Sidorenko E, Sokolova M, Pennanen AP, Kyheröinen S, Posern G, Foisner R, Vartiainen MK. Lamina-associated polypeptide 2α is required for intranuclear MRTF-A activity. Sci Rep 2022; 12:2306. [PMID: 35145145 PMCID: PMC8831594 DOI: 10.1038/s41598-022-06135-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 01/18/2022] [Indexed: 12/16/2022] Open
Abstract
Myocardin-related transcription factor A (MRTF-A), a coactivator of serum response factor (SRF), regulates the expression of many cytoskeletal genes in response to cytoplasmic and nuclear actin dynamics. Here we describe a novel mechanism to regulate MRTF-A activity within the nucleus by showing that lamina-associated polypeptide 2α (Lap2α), the nucleoplasmic isoform of Lap2, is a direct binding partner of MRTF-A, and required for the efficient expression of MRTF-A/SRF target genes. Mechanistically, Lap2α is not required for MRTF-A nuclear localization, unlike most other MRTF-A regulators, but is required for efficient recruitment of MRTF-A to its target genes. This regulatory step takes place prior to MRTF-A chromatin binding, because Lap2α neither interacts with, nor specifically influences active histone marks on MRTF-A/SRF target genes. Phenotypically, Lap2α is required for serum-induced cell migration, and deregulated MRTF-A activity may also contribute to muscle and proliferation phenotypes associated with loss of Lap2α. Our studies therefore add another regulatory layer to the control of MRTF-A-SRF-mediated gene expression, and broaden the role of Lap2α in transcriptional regulation.
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Affiliation(s)
| | - Maria Sokolova
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Antti P Pennanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Salla Kyheröinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Guido Posern
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Roland Foisner
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC), Vienna, Austria
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15
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Park SH, Kim SJ, Myung K, Lee KY. Characterization of subcellular localization of eukaryotic clamp loader/unloader and its regulatory mechanism. Sci Rep 2021; 11:21817. [PMID: 34751190 PMCID: PMC8575788 DOI: 10.1038/s41598-021-01336-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/13/2021] [Indexed: 11/27/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) plays a critical role as a processivity clamp for eukaryotic DNA polymerases and a binding platform for many DNA replication and repair proteins. The enzymatic activities of PCNA loading and unloading have been studied extensively in vitro. However, the subcellular locations of PCNA loaders, replication complex C (RFC) and CTF18-RFC-like-complex (RLC), and PCNA unloader ATAD5-RLC remain elusive, and the role of their subunits RFC2-5 is unknown. Here we used protein fractionation to determine the subcellular localization of RFC and RLCs and affinity purification to find molecular requirements for the newly defined location. All RFC/RLC proteins were detected in the nuclease-resistant pellet fraction. RFC1 and ATAD5 were not detected in the non-ionic detergent-soluble and nuclease-susceptible chromatin fractions, independent of cell cycle or exogenous DNA damage. We found that small RFC proteins contribute to maintaining protein levels of the RFC/RLCs. RFC1, ATAD5, and RFC4 co-immunoprecipitated with lamina-associated polypeptide 2 (LAP2) α which regulates intranuclear lamin A/C. LAP2α knockout consistently reduced detection of RFC/RLCs in the pellet fraction, while marginally affecting total protein levels. Our findings strongly suggest that PCNA-mediated DNA transaction occurs through regulatory machinery associated with nuclear structures, such as the nuclear matrix.
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Affiliation(s)
- Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea
| | - Seong-Jung Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.,Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.
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16
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The Retinoblastoma Tumor Suppressor Is Required for the NUP98-HOXA9-Induced Aberrant Nuclear Envelope Phenotype. Cells 2021; 10:cells10112851. [PMID: 34831074 PMCID: PMC8616146 DOI: 10.3390/cells10112851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022] Open
Abstract
Chromosomal translocations involving the nucleoporin NUP98 gene are recurrently identified in leukemia; yet, the cellular defects accompanying NUP98 fusion proteins are poorly characterized. NUP98 fusions cause changes in nuclear and nuclear envelope (NE) organization, in particular, in the nuclear lamina and the lamina associated polypeptide 2α (LAP2α), a regulator of the tumor suppressor retinoblastoma protein (RB). We demonstrate that, for NUP98-HOXA9 (NHA9), the best-studied NUP98 fusion protein, its effect(s) on nuclear architecture largely depend(s) on RB. Morphological alterations caused by the expression of NHA9 are largely diminished in the absence of RB, both in human cells expressing the human papillomavirus 16 E7 protein and in mouse embryonic fibroblasts lacking RB. We further show that NHA9 expression associates with distinct histone modification. Moreover, the pattern of trimethylation of histone H3 lysine-27 is affected by NHA9, again in an RB-dependent manner. Our results pinpoint to an unexpected interplay between NUP98 fusion proteins and RB, which may contribute to leukemogenesis.
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17
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Nuclear Dynamics and Chromatin Structure: Implications for Pancreatic Cancer. Cells 2021; 10:cells10102624. [PMID: 34685604 PMCID: PMC8534098 DOI: 10.3390/cells10102624] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/14/2022] Open
Abstract
Changes in nuclear shape have been extensively associated with the dynamics and functionality of cancer cells. In most normal cells, nuclei have a regular ellipsoid shape and minimal variation in nuclear size; however, an irregular nuclear contour and abnormal nuclear size is often observed in cancer, including pancreatic cancer. Furthermore, alterations in nuclear morphology have become the 'gold standard' for tumor staging and grading. Beyond the utility of altered nuclear morphology as a diagnostic tool in cancer, the implications of altered nuclear structure for the biology and behavior of cancer cells are profound as changes in nuclear morphology could impact cellular responses to physical strain, adaptation during migration, chromatin organization, and gene expression. Here, we aim to highlight and discuss the factors that regulate nuclear dynamics and their implications for pancreatic cancer biology.
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18
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Pawar S, Kutay U. The Diverse Cellular Functions of Inner Nuclear Membrane Proteins. Cold Spring Harb Perspect Biol 2021; 13:a040477. [PMID: 33753404 PMCID: PMC8411953 DOI: 10.1101/cshperspect.a040477] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nuclear compartment is delimited by a specialized expanded sheet of the endoplasmic reticulum (ER) known as the nuclear envelope (NE). Compared to the outer nuclear membrane and the contiguous peripheral ER, the inner nuclear membrane (INM) houses a unique set of transmembrane proteins that serve a staggering range of functions. Many of these functions reflect the exceptional position of INM proteins at the membrane-chromatin interface. Recent research revealed that numerous INM proteins perform crucial roles in chromatin organization, regulation of gene expression, genome stability, and mediation of signaling pathways into the nucleus. Other INM proteins establish mechanical links between chromatin and the cytoskeleton, help NE remodeling, or contribute to the surveillance of NE integrity and homeostasis. As INM proteins continue to gain prominence, we review these advancements and give an overview on the functional versatility of the INM proteome.
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Affiliation(s)
- Sumit Pawar
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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19
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Stixová L, Komůrková D, Svobodová Kovaříková A, Fagherazzi P, Bártová E. Localization of METTL16 at the Nuclear Periphery and the Nucleolus Is Cell Cycle-Specific and METTL16 Interacts with Several Nucleolar Proteins. Life (Basel) 2021; 11:life11070669. [PMID: 34357041 PMCID: PMC8305168 DOI: 10.3390/life11070669] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 12/16/2022] Open
Abstract
METTL16 methyltransferase is responsible for the methylation of N6-adenosine (m6A) in several RNAs. In mouse cells, we showed that the nuclear distribution of METTL16 is cell cycle-specific. In the G1/S phases, METTL16 accumulates to the nucleolus, while in the G2 phase, the level of METTL16 increases in the nucleoplasm. In metaphase and anaphase, there is a very low pool of the METTL16 protein, but in telophase, residual METTL16 appears to be associated with the newly formed nuclear lamina. In A-type lamin-depleted cells, we observed a reduction of METTL16 when compared with the wild-type counterpart. However, METTL16 does not interact with A-type and B-type lamins, but interacts with Lamin B Receptor (LBR) and Lap2α. Additionally, Lap2α depletion caused METTL16 downregulation in the nuclear pool. Furthermore, METTL16 interacted with DDB2, a key protein of the nucleotide excision repair (NER), and also with nucleolar proteins, including TCOF, NOLC1, and UBF1/2, but not fibrillarin. From this view, the METTL16 protein may also regulate the transcription of ribosomal genes because we observed that the high level of m6A in 18S rRNA appeared in cells with upregulated METTL16.
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Affiliation(s)
- Lenka Stixová
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; (D.K.); (A.S.K.); (P.F.)
- Correspondence: (L.S.); (E.B.); Tel.: +420-5-41517141 (E.B.)
| | - Denisa Komůrková
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; (D.K.); (A.S.K.); (P.F.)
| | - Alena Svobodová Kovaříková
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; (D.K.); (A.S.K.); (P.F.)
| | - Paolo Fagherazzi
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; (D.K.); (A.S.K.); (P.F.)
- Faculty of Science, Masaryk University, Kamenice 753/5, 601 77 Brno, Czech Republic
| | - Eva Bártová
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; (D.K.); (A.S.K.); (P.F.)
- Correspondence: (L.S.); (E.B.); Tel.: +420-5-41517141 (E.B.)
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20
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Liu SY, Ikegami K. Nuclear lamin phosphorylation: an emerging role in gene regulation and pathogenesis of laminopathies. Nucleus 2021; 11:299-314. [PMID: 33030403 PMCID: PMC7588210 DOI: 10.1080/19491034.2020.1832734] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Decades of studies have established that nuclear lamin polymers form the nuclear lamina, a protein meshwork that supports the nuclear envelope structure and tethers heterochromatin to the nuclear periphery. Much less is known about unpolymerized nuclear lamins in the nuclear interior, some of which are now known to undergo specific phosphorylation. A recent finding that phosphorylated lamins bind gene enhancer regions offers a new hypothesis that lamin phosphorylation may influence transcriptional regulation in the nuclear interior. In this review, we discuss the regulation, localization, and functions of phosphorylated lamins. We summarize kinases that phosphorylate lamins in a variety of biological contexts. Our discussion extends to laminopathies, a spectrum of degenerative disorders caused by lamin gene mutations, such as cardiomyopathies and progeria. We compare the prevailing hypothesis for laminopathy pathogenesis based on lamins’ function at the nuclear lamina with an emerging hypothesis based on phosphorylated lamins’ function in the nuclear interior.
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Affiliation(s)
- Sunny Yang Liu
- Department of Pediatrics, The University of Chicago , Chicago, Illinois, USA
| | - Kohta Ikegami
- Department of Pediatrics, The University of Chicago , Chicago, Illinois, USA.,Division of Molecular and Cardiovascular Biology, Cincinnati Children's Hospital Medical Center , Cincinnati, Ohio, USA
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21
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Ricci A, Orazi S, Biancucci F, Magnani M, Menotta M. The nucleoplasmic interactions among Lamin A/C-pRB-LAP2α-E2F1 are modulated by dexamethasone. Sci Rep 2021; 11:10099. [PMID: 33980953 PMCID: PMC8115688 DOI: 10.1038/s41598-021-89608-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 04/26/2021] [Indexed: 11/09/2022] Open
Abstract
Ataxia telangiectasia (AT) is a rare genetic neurodegenerative disease. To date, there is no available cure for the illness, but the use of glucocorticoids has been shown to alleviate the neurological symptoms associated with AT. While studying the effects of dexamethasone (dex) in AT fibroblasts, by chance we observed that the nucleoplasmic Lamin A/C was affected by the drug. In addition to the structural roles of A-type lamins, Lamin A/C has been shown to play a role in the regulation of gene expression and cell cycle progression, and alterations in the LMNA gene is cause of human diseases called laminopathies. Dex was found to improve the nucleoplasmic accumulation of soluble Lamin A/C and was capable of managing the large chromatin Lamin A/C scaffolds contained complex, thus regulating epigenetics in treated cells. In addition, dex modified the interactions of Lamin A/C with its direct partners lamin associated polypeptide (LAP) 2a, Retinoblastoma 1 (pRB) and E2F Transcription Factor 1 (E2F1), regulating local gene expression dependent on E2F1. These effects were differentially observed in both AT and wild type (WT) cells. To our knowledge, this is the first reported evidence of the role of dex in Lamin A/C dynamics in AT cells, and may represent a new area of research regarding the effects of glucocorticoids on AT. Moreover, future investigations could also be extended to healthy subjects or to other pathologies such as laminopathies since glucocorticoids may have other important effects in these contexts as well.
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Affiliation(s)
- Anastasia Ricci
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Sara Orazi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Federica Biancucci
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Via A. Saffi 2, 61029, Urbino, Italy.
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22
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The Long Linker Region of Telomere-Binding Protein TRF2 Is Responsible for Interactions with Lamins. Int J Mol Sci 2021; 22:ijms22073293. [PMID: 33804854 PMCID: PMC8036907 DOI: 10.3390/ijms22073293] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/15/2022] Open
Abstract
Telomere-binding factor 2 (TRF2) is part of the shelterin protein complex found at chromosome ends. Lamin A/C interacts with TRF2 and influences telomere position. TRF2 has an intrinsically disordered region between the ordered dimerization and DNA-binding domains. This domain is referred to as the long linker region of TRF2, or udTRF2. We suggest that udTRF2 might be involved in the interaction between TRF2 and lamins. The recombinant protein corresponding to the udTRF2 region along with polyclonal antibodies against this region were used in co-immunoprecipitation with purified lamina and nuclear extracts. Co-immunoprecipitation followed by Western blots and mass spectrometry indicated that udTRF2 interacts with lamins, preferably lamins A/C. The interaction did not involve any lamin-associated proteins, was not dependent on the post-translation modification of lamins, nor did it require their higher-order assembly. Besides lamins, a number of other udTRF2-interacting proteins were identified by mass spectrometry, including several heterogeneous nuclear ribonucleoproteins (hnRNP A2/B1, hnRNPA1, hnRNP A3, hnRNP K, hnRNP L, hnRNP M), splicing factors (SFPQ, NONO, SRSF1, and others), helicases (DDX5, DHX9, and Eif4a3l1), topoisomerase I, and heat shock protein 71, amongst others. Some of the identified interactors are known to be involved in telomere biology; the roles of the others remain to be investigated. Thus, the long linker region of TRF2 (udTRF2) is a regulatory domain responsible for the association between TRF2 and lamins and is involved in interactions with other proteins.
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Ito S, Ueda T, Yokoyama A, Fujihara A, Hongo F, Ukimura O. PCA3 controls chromatin organization and p53 signal activation by regulating LAP2α-lamin A complexes. Cancer Gene Ther 2021; 29:358-368. [PMID: 33758375 DOI: 10.1038/s41417-021-00314-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/28/2021] [Accepted: 02/16/2021] [Indexed: 11/09/2022]
Abstract
Prostate cancer antigen 3 (PCA3) is a prostate cancer-specific long noncoding RNA (lncRNA). Here, we report that lncRNA PCA3 plays a role in prostate cancer progression that is mediated by nucleoplasmic lamins. PCA3 interacts with the C-terminal region of lamina-associated polypeptide (LAP) 2α. The C-terminal region of LAP2α includes tumor suppressor protein retinoblastoma (pRb)- and lamin-binding domains, and it is necessary for the regulation and stabilization of the nucleoplasmic pool of lamin A. PCA3 inhibits the interaction of LAP2α with lamin A through binding with the C-terminus of LAP2α. The level of nucleoplasmic lamin A/C is increased by knockdown of PCA3. Together, the level of LAP2α within the nucleus is increased by PCA3 knockdown. In PCA3 knockdown cells, the levels of HP1γ, trimethylation of Lys9 on histone H3 (H3K9me3), and trimethylation of Lys36 on histone H3 (H3K36me3) are upregulated. In contrast, trimethylation of Lys4 on histone H3 (H3K4me3) is downregulated. We further demonstrate that activation of the p53 signaling pathway and cell cycle arrest are promoted in the absence of PCA3. These findings support a unique mechanism in which prostate cancer-specific lncRNA controls chromatin organization via regulation of the nucleoplasmic pool of lamins. This proposed mechanism suggests that cancer progression may be mediated by nuclear lamins.
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Affiliation(s)
- Saya Ito
- Department of Urology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto-City, Kyoto, Japan.
| | - Takashi Ueda
- Department of Urology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto-City, Kyoto, Japan
| | - Atsushi Yokoyama
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai-City, Miyagi, Japan
| | - Atsuko Fujihara
- Department of Urology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto-City, Kyoto, Japan
| | - Fumiya Hongo
- Department of Urology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto-City, Kyoto, Japan
| | - Osamu Ukimura
- Department of Urology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto-City, Kyoto, Japan
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Naetar N, Georgiou K, Knapp C, Bronshtein I, Zier E, Fichtinger P, Dechat T, Garini Y, Foisner R. LAP2alpha maintains a mobile and low assembly state of A-type lamins in the nuclear interior. eLife 2021; 10:e63476. [PMID: 33605210 PMCID: PMC7939549 DOI: 10.7554/elife.63476] [Citation(s) in RCA: 7] [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: 09/28/2020] [Accepted: 02/18/2021] [Indexed: 01/08/2023] Open
Abstract
Lamins form stable filaments at the nuclear periphery in metazoans. Unlike B-type lamins, lamins A and C localize also in the nuclear interior, where they interact with lamin-associated polypeptide 2 alpha (LAP2α). Using antibody labeling, we previously observed a depletion of nucleoplasmic A-type lamins in mouse cells lacking LAP2α. Here, we show that loss of LAP2α actually causes formation of larger, biochemically stable lamin A/C structures in the nuclear interior that are inaccessible to lamin A/C antibodies. While nucleoplasmic lamin A forms from newly expressed pre-lamin A during processing and from soluble mitotic lamins in a LAP2α-independent manner, binding of LAP2α to lamin A/C during interphase inhibits formation of higher order structures, keeping nucleoplasmic lamin A/C in a mobile state independent of lamin A/C S22 phosphorylation. We propose that LAP2α is essential to maintain a mobile lamin A/C pool in the nuclear interior, which is required for proper nuclear functions.
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Affiliation(s)
- Nana Naetar
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
| | - Konstantina Georgiou
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
| | - Christian Knapp
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
| | - Irena Bronshtein
- Physics Department and Nanotechnology Institute, Bar Ilan UniversityRamat GanIsrael
| | - Elisabeth Zier
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
| | - Petra Fichtinger
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
| | - Thomas Dechat
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
| | - Yuval Garini
- Physics Department and Nanotechnology Institute, Bar Ilan UniversityRamat GanIsrael
| | - Roland Foisner
- Max Perutz Labs, Center for Medical Biochemistry, Medical University of Vienna, Vienna Biocenter Campus (VBC)ViennaAustria
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Karoutas A, Akhtar A. Functional mechanisms and abnormalities of the nuclear lamina. Nat Cell Biol 2021; 23:116-126. [PMID: 33558730 DOI: 10.1038/s41556-020-00630-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 12/22/2020] [Indexed: 01/30/2023]
Abstract
Alterations in nuclear shape are present in human diseases and ageing. A compromised nuclear lamina is molecularly interlinked to altered chromatin functions and genomic instability. Whether these alterations are a cause or a consequence of the pathological state are important questions in biology. Here, we summarize the roles of nuclear envelope components in chromatin organization, phase separation and transcriptional and epigenetic regulation. Examining these functions in healthy backgrounds will guide us towards a better understanding of pathological alterations.
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Affiliation(s)
- Adam Karoutas
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,Francis Crick Institute, London, UK
| | - Asifa Akhtar
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
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Zhang X, Shao X, Zhang R, Zhu R, Feng R. Integrated analysis reveals the alterations that LMNA interacts with euchromatin in LMNA mutation-associated dilated cardiomyopathy. Clin Epigenetics 2021; 13:3. [PMID: 33407844 PMCID: PMC7788725 DOI: 10.1186/s13148-020-00996-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/20/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Dilated cardiomyopathy (DCM) is a serious cardiac heterogeneous pathological disease, which may be caused by mutations in the LMNA gene. Lamins interact with not only lamina-associated domains (LADs) but also euchromatin by alone or associates with the lamina-associated polypeptide 2 alpha (LAP2α). Numerous studies have documented that LMNA regulates gene expression by interacting with LADs in heterochromatin. However, the role of LMNA in regulating euchromatin in DCM is poorly understood. Here, we determine the differential binding genes on euchromatin in DCM induced by LMNA mutation by performing an integrated analysis of bioinformatics and explore the possible molecular pathogenesis mechanism. RESULTS Six hundred twenty-three and 4484 differential binding genes were identified by ChIP-seq technology. The ChIP-seq analysis results and matched RNA-Seq transcriptome data were integrated to further validate the differential binding genes of ChIP-seq. Five and 60 candidate genes involved in a series of downstream analysis were identified. Finally, 4 key genes (CREBBP, PPP2R2B, BMP4, and BMP7) were harvested, and these genes may regulate LMNA mutation-induced DCM through WNT/β-catenin or TGFβ-BMP pathways. CONCLUSIONS We identified four key genes that may serve as potential biomarkers and novel therapeutic targets. Our study also illuminates the possible molecular pathogenesis mechanism that the abnormal binding between LMNA or LAP2α-lamin A/C complexes and euchromatin DNA in LMNA mutations, which may cause DCM through the changes of CREBBP, PPP2R2B, BMP4, BMP7 expressions, and the dysregulation of WNT/β-catenin or TGFβ-BMP pathways, providing valuable insights to improve the occurrence and development of DCM.
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Affiliation(s)
- Xiaolin Zhang
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Xiuli Shao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Ruijia Zhang
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Rongli Zhu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Rui Feng
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China.
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Mirza AN, Gonzalez F, Ha SK, Oro AE. The Sky's the LEMit: New insights into nuclear structure regulation of transcription factor activity. Curr Opin Cell Biol 2020; 68:173-180. [PMID: 33227657 DOI: 10.1016/j.ceb.2020.10.006] [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: 07/07/2020] [Revised: 09/24/2020] [Accepted: 10/08/2020] [Indexed: 12/31/2022]
Abstract
The nucleoskeleton has been associated with partitioning the genome into active and inactive compartments that dictate local transcription factor (TF) activity. However, recent data indicate that the nucleoskeleton and TFs reciprocally influence each other in dynamic TF trafficking pathways through the functions of LEM proteins. While the conserved peripheral recruitment of TFs by LEM proteins has been viewed as a mechanism of repressing transcription, a diversity of release mechanisms from the lamina suggest this compartment serves as a refuge for nuclear TF accumulation for rapid mobilization and signal stability. Detailed mechanisms suggest that TFs toggle between nuclear lamina refuge and nuclear matrix lamin-LEM protein complexes at sites of active transcription. In this review we will highlight emerging LEM functions acting at the interface of chromatin and nucleoskeleton to create TF trafficking networks.
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Affiliation(s)
- Amar N Mirza
- Program in Epithelial Biology, Stanford University School of Medicine Stanford, CA, 94305, USA
| | - Fernanda Gonzalez
- Program in Epithelial Biology, Stanford University School of Medicine Stanford, CA, 94305, USA
| | - Sierra K Ha
- Program in Epithelial Biology, Stanford University School of Medicine Stanford, CA, 94305, USA
| | - Anthony E Oro
- Program in Epithelial Biology, Stanford University School of Medicine Stanford, CA, 94305, USA.
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Ikegami K, Secchia S, Almakki O, Lieb JD, Moskowitz IP. Phosphorylated Lamin A/C in the Nuclear Interior Binds Active Enhancers Associated with Abnormal Transcription in Progeria. Dev Cell 2020; 52:699-713.e11. [PMID: 32208162 DOI: 10.1016/j.devcel.2020.02.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 12/13/2019] [Accepted: 02/13/2020] [Indexed: 02/06/2023]
Abstract
LMNA encodes nuclear Lamin A/C that tethers lamina-associated domains (LADs) to the nuclear periphery. Mutations in LMNA cause degenerative disorders including the premature aging disorder Hutchinson-Gilford progeria, but the mechanisms are unknown. We report that Ser22-phosphorylated (pS22) Lamin A/C was localized to the nuclear interior in human fibroblasts throughout the cell cycle. pS22-Lamin A/C interacted with a subset of putative active enhancers, not LADs, at locations co-bound by the transcriptional activator c-Jun. In progeria-patient fibroblasts, a subset of pS22-Lamin A/C-binding sites were lost, whereas new pS22-Lamin A/C-binding sites emerged in normally quiescent loci. New pS22-Lamin A/C binding was accompanied by increased histone acetylation, increased c-Jun binding, and upregulation of nearby genes implicated in progeria pathophysiology. These results suggest that Lamin A/C regulates gene expression by enhancer binding. Disruption of the gene regulatory rather than LAD tethering function of Lamin A/C may underlie the pathogenesis of disorders caused by LMNA mutations.
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Affiliation(s)
- Kohta Ikegami
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA; Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA.
| | - Stefano Secchia
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA; Department of Biology, Lunds University, Lund 22362, Sweden
| | - Omar Almakki
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA
| | - Jason D Lieb
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Ivan P Moskowitz
- Department of Pediatrics, The University of Chicago, Chicago, IL 60637, USA; Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA; Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
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Lunin S, Khrenov M, Glushkova O, Parfenyuk S, Novoselova T, Novoselova E. Precursors of thymic peptides as stress sensors. Expert Opin Biol Ther 2020; 20:1461-1475. [PMID: 32700610 DOI: 10.1080/14712598.2020.1800636] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION A large volume of data indicates that the known thymic hormones, thymulin, thymopoietin, thymosin-α, thymosin-β, and thymic humoral factor-y2, exhibit different spectra of activities. Although large in volume, available data are rather fragmented, resulting in a lack of understanding of the role played by thymic hormones in immune homeostasis. AREA COVERED Existing data compartmentalizes the effect of thymic peptides into 2 categories: influence on immune cells and interconnection with neuroendocrine systems. The current study draws attention to a third aspect of the thymic peptide effect that has not been clarified yet, wherein ubiquitous and highly abundant intranuclear precursors of so called 'thymic peptides' play a fundamental role in all somatic cells. EXPERT OPINION Our analysis indicated that, under certain stress-related conditions, these precursors are cleaved to form immunologically active peptides that rapidly leave the nucleus and intracellular spaces, to send 'distress signals' to the immune system, thereby acting as stress sensors. We propose that these peptides may form a link between somatic cells and immune as well as neuroendocrine systems. This model may provide a better understanding of the mechanisms underlying immune homeostasis, leading thereby to the development of new therapeutic regimes utilizing the characteristics of thymic peptides.
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Affiliation(s)
- Sergey Lunin
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Maxim Khrenov
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Olga Glushkova
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Svetlana Parfenyuk
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Tatyana Novoselova
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - E Novoselova
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
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Tang Y, Zhang X, Ge W, Zhou Y. Knockdown of LAP2α inhibits osteogenic differentiation of human adipose-derived stem cells by activating NF-κB. Stem Cell Res Ther 2020; 11:263. [PMID: 32611381 PMCID: PMC7329510 DOI: 10.1186/s13287-020-01774-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/01/2020] [Accepted: 06/16/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Lamina-associated polypeptide 2α (LAP2α) is a nucleoplasmic protein that has been involved in the regulation of the cell cycle, gene transcription, and adult stem cell function. LAP2α down-regulation is linked to age-related osteoporosis and bone deformities; however, the underlying mechanisms remain obscure. The present study aimed to elucidate the function of LAP2α in the osteogenic differentiation of human adipose-derived stem cells (hASCs), which are attractive sources for bone tissue engineering. METHODS The expression of LAP2α during the osteogenic differentiation of hASCs was detected firstly. A loss of function investigation was then carried out to characterize the function of LAP2α in osteogenic differentiation of hASCs both in vitro and in vivo. Moreover, RNA-sequences, western blotting, and confocal analyses were performed to clarify the molecular mechanism of LAP2α-regulated osteogenesis. RESULTS We found that LAP2α expression was upregulated upon osteogenic induction. Both in vitro and in vivo experiments indicated that LAP2α knockdown resulted in impaired osteogenic differentiation of hASCs. Mechanistically, we revealed that LAP2α deficiency activated nuclear factor kappa B (NF-κB) signaling by controlling the cytoplasmic-nuclear translocation of p65. CONCLUSIONS Collectively, our findings revealed that LAP2α functions as an essential regulator for osteogenesis of hASCs by modulating NF-κB signaling, thus providing novel insights for mesenchymal stem cell-mediated bone tissue engineering.
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Affiliation(s)
- Yiman Tang
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.,Fourth Clinical Division, Peking University School and Hospital of Stomatology, Beijing, China
| | - Xiao Zhang
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.,National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Beijing, China
| | - Wenshu Ge
- National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Beijing, China. .,Department of General Dentistry II, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing, China.
| | - Yongsheng Zhou
- Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, China.,National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Beijing, China
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Lamin A/C Mechanotransduction in Laminopathies. Cells 2020; 9:cells9051306. [PMID: 32456328 PMCID: PMC7291067 DOI: 10.3390/cells9051306] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/20/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022] Open
Abstract
Mechanotransduction translates forces into biological responses and regulates cell functionalities. It is implicated in several diseases, including laminopathies which are pathologies associated with mutations in lamins and lamin-associated proteins. These pathologies affect muscle, adipose, bone, nerve, and skin cells and range from muscular dystrophies to accelerated aging. Although the exact mechanisms governing laminopathies and gene expression are still not clear, a strong correlation has been found between cell functionality and nuclear behavior. New theories base on the direct effect of external force on the genome, which is indeed sensitive to the force transduced by the nuclear lamina. Nuclear lamina performs two essential functions in mechanotransduction pathway modulating the nuclear stiffness and governing the chromatin remodeling. Indeed, A-type lamin mutation and deregulation has been found to affect the nuclear response, altering several downstream cellular processes such as mitosis, chromatin organization, DNA replication-transcription, and nuclear structural integrity. In this review, we summarize the recent findings on the molecular composition and architecture of the nuclear lamina, its role in healthy cells and disease regulation. We focus on A-type lamins since this protein family is the most involved in mechanotransduction and laminopathies.
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Abstract
At the nuclear periphery, associations of chromatin with the nuclear lamina through lamina-associated domains (LADs) aid functional organization of the genome. We review the organization of LADs and provide evidence of LAD heterogeneity from cell ensemble and single-cell data. LADs are typically repressive environments in the genome; nonetheless, we discuss findings of lamin interactions with regulatory elements of active genes, and the role lamins may play in genome regulation. We address the relationship between LADs and other genome organizers, and the involvement of LADs in laminopathies. The current data lay the basis for future studies on the significance of lamin-chromatin interactions in health and disease.
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Affiliation(s)
- Nolwenn Briand
- Department of Molecular Medicine, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424, Oslo, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway.
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424, Oslo, Norway.
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Wintner O, Hirsch‐Attas N, Schlossberg M, Brofman F, Friedman R, Kupervaser M, Kitsberg D, Buxboim A. A Unified Linear Viscoelastic Model of the Cell Nucleus Defines the Mechanical Contributions of Lamins and Chromatin. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1901222. [PMID: 32328409 PMCID: PMC7175345 DOI: 10.1002/advs.201901222] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 01/22/2020] [Indexed: 05/26/2023]
Abstract
The cell nucleus is constantly subjected to externally applied forces. During metazoan evolution, the nucleus has been optimized to allow physical deformability while protecting the genome under load. Aberrant nucleus mechanics can alter cell migration across narrow spaces in cancer metastasis and immune response and disrupt nucleus mechanosensitivity. Uncovering the mechanical roles of lamins and chromatin is imperative for understanding the implications of physiological forces on cells and nuclei. Lamin-knockout and -rescue fibroblasts and probed nucleus response to physiologically relevant stresses are generated. A minimal viscoelastic model is presented that captures dynamic resistance across different cell types, lamin composition, phosphorylation states, and chromatin condensation. The model is conserved at low and high loading and is validated by micropipette aspiration and nanoindentation rheology. A time scale emerges that separates between dominantly elastic and dominantly viscous regimes. While lamin-A and lamin-B1 contribute to nucleus stiffness, viscosity is specified mostly by lamin-A. Elastic and viscous association of lamin-B1 and lamin-A is supported by transcriptional and proteomic profiling analyses. Chromatin decondensation quantified by electron microscopy softens the nucleus unless lamin-A is expressed. A mechanical framework is provided for assessing nucleus response to applied forces in health and disease.
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Affiliation(s)
- Oren Wintner
- Department of Cell and Developmental BiologyThe Alexander Silberman Institute of Life SciencesThe Hebrew University of JerusalemJerusalem9190401Israel
- Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringJerusalem9190416Israel
| | - Nivi Hirsch‐Attas
- Department of Cell and Developmental BiologyThe Alexander Silberman Institute of Life SciencesThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Miriam Schlossberg
- Department of Cell and Developmental BiologyThe Alexander Silberman Institute of Life SciencesThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Fani Brofman
- Department of Cell and Developmental BiologyThe Alexander Silberman Institute of Life SciencesThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Roy Friedman
- Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringJerusalem9190416Israel
| | - Meital Kupervaser
- The de Botton Institute for Protein ProfilingThe Nancy and Stephen Grand Israel National Center for Personalized MedicineWeizmann Institute of ScienceRehovot7610001Israel
| | - Danny Kitsberg
- Department of Cell and Developmental BiologyThe Alexander Silberman Institute of Life SciencesThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Amnon Buxboim
- Department of Cell and Developmental BiologyThe Alexander Silberman Institute of Life SciencesThe Hebrew University of JerusalemJerusalem9190401Israel
- Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringJerusalem9190416Israel
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Lamin A/C Assembly Defects in LMNA-Congenital Muscular Dystrophy Is Responsible for the Increased Severity of the Disease Compared with Emery-Dreifuss Muscular Dystrophy. Cells 2020; 9:cells9040844. [PMID: 32244403 PMCID: PMC7226786 DOI: 10.3390/cells9040844] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 01/13/2023] Open
Abstract
LMNA encodes for Lamin A/C, type V intermediate filaments that polymerize under the inner nuclear membrane to form the nuclear lamina. A small fraction of Lamin A/C, less polymerized, is also found in the nucleoplasm. Lamin A/C functions include roles in nuclear resistance to mechanical stress and gene regulation. LMNA mutations are responsible for a wide variety of pathologies, including Emery–Dreifuss (EDMD) and LMNA-related congenital muscular dystrophies (L-CMD) without clear genotype–phenotype correlations. Both diseases presented with striated muscle disorders although L-CMD symptoms appear much earlier and are more severe. Seeking for pathomechanical differences to explain the severity of L-CMD mutations, we performed an in silico analysis of the UMD-LMNA database and found that L-CMD mutations mainly affect residues involved in Lamin dimer and tetramer stability. In line with this, we found increased nucleoplasmic Lamin A/C in L-CMD patient fibroblasts and mouse myoblasts compared to the control and EDMD. L-CMD myoblasts show differentiation defects linked to their inability to upregulate muscle specific nuclear envelope (NE) proteins expression. NE proteins were mislocalized, leading to misshapen nuclei. We conclude that these defects are due to both the absence of Lamin A/C from the nuclear lamina and its maintenance in the nucleoplasm of myotubes.
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35
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Chojnowski A, Ong PF, Foo MXR, Liebl D, Hor L, Stewart CL, Dreesen O. Heterochromatin loss as a determinant of progerin-induced DNA damage in Hutchinson-Gilford Progeria. Aging Cell 2020; 19:e13108. [PMID: 32087607 PMCID: PMC7059134 DOI: 10.1111/acel.13108] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 12/15/2019] [Accepted: 01/02/2020] [Indexed: 12/13/2022] Open
Abstract
Hutchinson-Gilford progeria is a premature aging syndrome caused by a truncated form of lamin A called progerin. Progerin expression results in a variety of cellular defects including heterochromatin loss, DNA damage, impaired proliferation and premature senescence. It remains unclear how these different progerin-induced phenotypes are temporally and mechanistically linked. To address these questions, we use a doxycycline-inducible system to restrict progerin expression to different stages of the cell cycle. We find that progerin expression leads to rapid and widespread loss of heterochromatin in G1-arrested cells, without causing DNA damage. In contrast, progerin triggers DNA damage exclusively during late stages of DNA replication, when heterochromatin is normally replicated, and preferentially in cells that have lost heterochromatin. Importantly, removal of progerin from G1-arrested cells restores heterochromatin levels and results in no permanent proliferative impediment. Taken together, these results delineate the chain of events that starts with progerin expression and ultimately results in premature senescence. Moreover, they provide a proof of principle that removal of progerin from quiescent cells restores heterochromatin levels and their proliferative capacity to normal levels.
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Affiliation(s)
- Alexandre Chojnowski
- Developmental and Regenerative BiologyInstitute of Medical BiologySingaporeSingapore
| | - Peh Fern Ong
- Cell Ageing, Skin Research Institute SingaporeSingaporeSingapore
| | | | - David Liebl
- A*STAR Microscopy PlatformSingaporeSingapore
| | - Louis‐Peter Hor
- Cell Ageing, Skin Research Institute SingaporeSingaporeSingapore
| | - Colin L. Stewart
- Developmental and Regenerative BiologyInstitute of Medical BiologySingaporeSingapore
| | - Oliver Dreesen
- Cell Ageing, Skin Research Institute SingaporeSingaporeSingapore
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36
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Ishii H, Park WY, So J, Kuhn S, Koparde VN, Pang Y, Greten TF, Hollander MC, Yang L. Loss of myeloid-specific lamin A/C drives lung metastasis through Gfi-1 and C/EBPε-mediated granulocytic differentiation. Mol Carcinog 2020; 59:679-690. [PMID: 31912614 PMCID: PMC7282947 DOI: 10.1002/mc.23147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 12/20/2022]
Abstract
The immune-suppressive tumor microenvironment promotes metastatic spread and outgrowth. One of the major contributors is tumor-associated myeloid cells. However, the molecular mechanisms regulating their differentiation and function are not well understood. Here we report lamin A/C, a nuclear lamina protein associated with chromatin remodeling, was one of the critical regulators in cellular reprogramming of tumor-associated myeloid cells. Using myeloid-specific lamin A/C knockout mice and triple-negative breast cancer (TNBC) mouse models, we discovered that the loss of lamin A/C drives CD11b+ Ly6G+ granulocytic lineage differentiation, alters the production of inflammatory chemokines, decreases host antitumor immunity, and increases metastasis. The underlying mechanisms involve an increased H3K4me3 leading to the upregulation of transcription factors (TFs) Gfi-1 and C/EBPε. Decreased lamin A/C and increased Gfi-1 and C/EBPε were also found in the granulocytic subset in the peripheral blood of human cancer patients. Our data provide a mechanistic understanding of myeloid lineage differentiation and function in the immune-suppressive microenvironment in TNBC metastasis.
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Affiliation(s)
- Hiroki Ishii
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Woo-Yong Park
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Jaeyoung So
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Skyler Kuhn
- CCR Collaborative Bioinformatics Resource, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland.,Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research Sponsored by the National Cancer Institute, NIH, Frederick, Maryland
| | - Vishal N Koparde
- CCR Collaborative Bioinformatics Resource, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland.,Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research Sponsored by the National Cancer Institute, NIH, Frederick, Maryland
| | - Yanli Pang
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Tim F Greten
- Thoracic and Gastrointestinal Malignancies Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - M Christine Hollander
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Li Yang
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
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37
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Yeo JH, Lam YW, Fraser ST. Cellular dynamics of mammalian red blood cell production in the erythroblastic island niche. Biophys Rev 2019; 11:873-894. [PMID: 31418139 PMCID: PMC6874942 DOI: 10.1007/s12551-019-00579-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022] Open
Abstract
Red blood cells, or erythrocytes, make up approximately a quarter of all cells in the human body with over 2 billion new erythrocytes made each day in a healthy adult human. This massive cellular production system is coupled with a set of cell biological processes unique to mammals, in particular, the elimination of all organelles, and the expulsion and destruction of the condensed erythroid nucleus. Erythrocytes from birds, reptiles, amphibians and fish possess nuclei, mitochondria and other organelles: erythrocytes from mammals lack all of these intracellular components. This review will focus on the dynamic changes that take place in developing erythroid cells that are interacting with specialized macrophages in multicellular clusters termed erythroblastic islands. Proerythroblasts enter the erythroblastic niche as large cells with active nuclei, mitochondria producing heme and energy, and attach to the central macrophage via a range of adhesion molecules. Proerythroblasts then mature into erythroblasts and, following enucleation, in reticulocytes. When reticulocytes exit the erythroblastic island, they are smaller cells, without nuclei and with few mitochondria, possess some polyribosomes and have a profoundly different surface molecule phenotype. Here, we will review, step-by-step, the biophysical mechanisms that regulate the remarkable process of erythropoiesis with a particular focus on the events taking place in the erythroblastic island niche. This is presented from the biological perspective to offer insight into the elements of red blood cell development in the erythroblastic island niche which could be further explored with biophysical modelling systems.
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Affiliation(s)
- Jia Hao Yeo
- Discipline of Anatomy and Histology, School of Medical Sciences, University of Sydney, Sydney, Australia.
- School of Chemistry, University of Sydney, Sydney, Australia.
- Discipline of Physiology, School of Medical Sciences, University of Sydney, Sydney, Australia.
| | - Yun Wah Lam
- Department of Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Stuart T Fraser
- Discipline of Anatomy and Histology, School of Medical Sciences, University of Sydney, Sydney, Australia.
- Discipline of Physiology, School of Medical Sciences, University of Sydney, Sydney, Australia.
- Bosch Institute, School of Medical Sciences, University of Sydney, Sydney, Australia.
- University of Sydney Nano Institute, Sydney, Australia.
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38
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Briand N, Collas P. Laminopathy-causing lamin A mutations reconfigure lamina-associated domains and local spatial chromatin conformation. Nucleus 2019. [PMID: 29517398 PMCID: PMC5973257 DOI: 10.1080/19491034.2018.1449498] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The nuclear lamina contributes to the regulation of gene expression and to chromatin organization. Mutations in A-type nuclear lamins cause laminopathies, some of which are associated with a loss of heterochromatin at the nuclear periphery. Until recently however, little if any information has been provided on where and how lamin A interacts with the genome and on how disease-causing lamin A mutations may rearrange genome conformation. Here, we review aspects of nuclear lamin association with the genome. We highlight recent evidence of reorganization of lamin A-chromatin interactions in cellular models of laminopathies, and implications on the 3-dimensional rearrangement of chromatin in these models, including patient cells. We discuss how a hot-spot lipodystrophic lamin A mutation alters chromatin conformation and epigenetic patterns at an anti-adipogenic locus, and conclude with remarks on links between lamin A, Polycomb and the pathophysiology of laminopathies. The recent findings presented here collectively argue towards a deregulation of large-scale and local spatial genome organization by a subset of lamin A mutations causing laminopathies.
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Affiliation(s)
- Nolwenn Briand
- a Department of Molecular Medicine , Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo , Oslo , Norway
| | - Philippe Collas
- a Department of Molecular Medicine , Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo , Oslo , Norway.,b Norwegian Center for Stem Cell Research, Department of Immunology and Transfusion Medicine , Oslo University Hospital , Oslo , Norway
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39
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Bianchi A, Manti PG, Lucini F, Lanzuolo C. Mechanotransduction, nuclear architecture and epigenetics in Emery Dreifuss Muscular Dystrophy: tous pour un, un pour tous. Nucleus 2019; 9:276-290. [PMID: 29619865 PMCID: PMC5973142 DOI: 10.1080/19491034.2018.1460044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The alteration of the several roles that Lamin A/C plays in the mammalian cell leads to a broad spectrum of pathologies that – all together – are named laminopathies. Among those, the Emery Dreifuss Muscular Dystrophy (EDMD) is of particular interest as, despite the several known mutations of Lamin A/C, the genotype–phenotype correlation still remains poorly understood; this suggests that the epigenetic background of patients might play an important role during the time course of the disease. Historically, both a mechanical role of Lamin A/C and a regulative one have been suggested as the driving force of laminopathies; however, those two hypotheses are not mutually exclusive. Recent scientific evidence shows that Lamin A/C sustains the correct gene expression at the epigenetic level thanks to the Lamina Associated Domains (LADs) reorganization and the crosstalk with the Polycomb Group of Proteins (PcG). Furthermore, the PcG-dependent histone mark H3K27me3 increases under mechanical stress, finally pointing out the link between the mechano-properties of the nuclear lamina and epigenetics. Here, we summarize the emerging mechanisms that could explain the high variability seen in Emery Dreifuss muscular dystrophy.
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Affiliation(s)
- Andrea Bianchi
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | | | - Federica Lucini
- b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | - Chiara Lanzuolo
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy.,c Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy
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40
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Sun DP, Liew PL, Lin CC, Hung ST, Chen TC, Fang CL, Lin KY. Clinicopathologic and Prognostic Significance of Thymopoietin-α Overexpression in Gastric Cancer. J Cancer 2019; 10:5099-5107. [PMID: 31602262 PMCID: PMC6775605 DOI: 10.7150/jca.30738] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 07/22/2019] [Indexed: 12/18/2022] Open
Abstract
As one of the deadliest and most common malignancies in the world, gastric cancer (GC) represents a serious health threat. Despite recent advances in the field, the prognosis of patients with metastatic GC remains poor. In this study, we aimed to investigate the clinical impact of the alpha subunit of the nuclear structural protein thymopoietin (TMPO-α) in GC. The expression of TMPO-α in seven gastric cell lines was detected by immunoblotting. The expression level of TMPO-α levels in gastric tissues collected from 145 GC patients was examined by immunohistochemistry. The correlations between TMPO-α expression level and clinicopathologic parameters, as well as the association of TMPO-α expression with overall survival, were assessed. Immunohistochemistry showed that the expression of TMPO-α was significantly higher in GC tissues and cells in comparison with non-tumor tissues and cells. Furthermore, the overexpression of TMPO-α in gastric tissues (56%) was positively associated with Lauren classification (P = 0.0159), nodal status (P = 0.0265), distant metastasis (P < 0.0001), stage (P = 0.0367), and degree of differentiation (P = 0.0009). Patients with high TMPO-α levels had a significantly poorer overall survival than those with low levels (P = 0.001). Multivariate Cox regression analysis also indicated that TMPO-α was an independent prognostic marker for GC (P = 0.045). In addition, studies conducted in GC cells indicated that knockdown of TMPO-α suppressed cell proliferation and invasion. These findings indicate that TMPO-α overexpression can predict clinicopathologic features and the outcome of patients with GC.
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Affiliation(s)
- Ding-Ping Sun
- Department of Surgery, Chi Mei Medical Center, Tainan, Taiwan.,Department of Food Science and Technology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Phui-Ly Liew
- Department of Pathology, Shuang Ho Hospital, Taipei Medical University, New Taipei, Taiwan.,Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Chan Lin
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan
| | - Shih-Ting Hung
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan
| | - Tai-Chi Chen
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan
| | - Chia-Lang Fang
- Department of Pathology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Pathology, Wang Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Kai-Yuan Lin
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan.,Department of Biotechnology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
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41
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Buchwalter A, Kaneshiro JM, Hetzer MW. Coaching from the sidelines: the nuclear periphery in genome regulation. Nat Rev Genet 2019; 20:39-50. [PMID: 30356165 DOI: 10.1038/s41576-018-0063-5] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The genome is packaged and organized nonrandomly within the 3D space of the nucleus to promote efficient gene expression and to faithfully maintain silencing of heterochromatin. The genome is enclosed within the nucleus by the nuclear envelope membrane, which contains a set of proteins that actively participate in chromatin organization and gene regulation. Technological advances are providing views of genome organization at unprecedented resolution and are beginning to reveal the ways that cells co-opt the structures of the nuclear periphery for nuclear organization and gene regulation. These genome regulatory roles of proteins of the nuclear periphery have important influences on development, disease and ageing.
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Affiliation(s)
- Abigail Buchwalter
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, USA.,Department of Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Jeanae M Kaneshiro
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Martin W Hetzer
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.
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42
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Alvarado-Kristensson M, Rosselló CA. The Biology of the Nuclear Envelope and Its Implications in Cancer Biology. Int J Mol Sci 2019; 20:E2586. [PMID: 31137762 PMCID: PMC6566445 DOI: 10.3390/ijms20102586] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/07/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022] Open
Abstract
The formation of the nuclear envelope and the subsequent compartmentalization of the genome is a defining feature of eukaryotes. Traditionally, the nuclear envelope was purely viewed as a physical barrier to preserve genetic material in eukaryotic cells. However, in the last few decades, it has been revealed to be a critical cellular component in controlling gene expression and has been implicated in several human diseases. In cancer, the relevance of the cell nucleus was first reported in the mid-1800s when an altered nuclear morphology was observed in tumor cells. This review aims to give a current and comprehensive view of the role of the nuclear envelope on cancer first by recapitulating the changes of the nuclear envelope during cell division, second, by reviewing the role of the nuclear envelope in cell cycle regulation, signaling, and the regulation of the genome, and finally, by addressing the nuclear envelope link to cell migration and metastasis and its use in cancer prognosis.
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Affiliation(s)
- Maria Alvarado-Kristensson
- Molecular Pathology, Department of Translational Medicine, Lund University, Skåne University Hospital, 20502 Malmö, Sweden.
| | - Catalina Ana Rosselló
- Laboratory of Molecular Cell Biomedicine, University of the Balearic Islands, 07121 Palma de Mallorca, Spain.
- Lipopharma Therapeutics, Isaac Newton, 07121 Palma de Mallorca, Spain.
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43
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Briand N, Guénantin AC, Jeziorowska D, Shah A, Mantecon M, Capel E, Garcia M, Oldenburg A, Paulsen J, Hulot JS, Vigouroux C, Collas P. The lipodystrophic hotspot lamin A p.R482W mutation deregulates the mesodermal inducer T/Brachyury and early vascular differentiation gene networks. Hum Mol Genet 2019; 27:1447-1459. [PMID: 29438482 DOI: 10.1093/hmg/ddy055] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 02/08/2018] [Indexed: 12/21/2022] Open
Abstract
The p.R482W hotspot mutation in A-type nuclear lamins causes familial partial lipodystrophy of Dunnigan-type (FPLD2), a lipodystrophic syndrome complicated by early onset atherosclerosis. Molecular mechanisms underlying endothelial cell dysfunction conferred by the lamin A mutation remain elusive. However, lamin A regulates epigenetic developmental pathways and mutations could perturb these functions. Here, we demonstrate that lamin A R482W elicits endothelial differentiation defects in a developmental model of FPLD2. Genome modeling in fibroblasts from patients with FPLD2 caused by the lamin A R482W mutation reveals repositioning of the mesodermal regulator T/Brachyury locus towards the nuclear center relative to normal fibroblasts, suggesting enhanced activation propensity of the locus in a developmental model of FPLD2. Addressing this issue, we report phenotypic and transcriptional alterations in mesodermal and endothelial differentiation of induced pluripotent stem cells we generated from a patient with R482W-associated FPLD2. Correction of the LMNA mutation ameliorates R482W-associated phenotypes and gene expression. Transcriptomics links endothelial differentiation defects to decreased Polycomb-mediated repression of the T/Brachyury locus and over-activation of T target genes. Binding of the Polycomb repressor complex 2 to T/Brachyury is impaired by the mutated lamin A network, which is unable to properly associate with the locus. This leads to a deregulation of vascular gene expression over time. By connecting a lipodystrophic hotspot lamin A mutation to a disruption of early mesodermal gene expression and defective endothelial differentiation, we propose that the mutation rewires the fate of several lineages, resulting in multi-tissue pathogenic phenotypes.
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Affiliation(s)
- Nolwenn Briand
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway.,Sorbonne Université, Inserm UMR S938, Saint-Antoine Research Centre, Institute of Cardiometabolism and Nutrition, 75012 Paris, France
| | - Anne-Claire Guénantin
- Sorbonne Université, Inserm UMR S938, Saint-Antoine Research Centre, Institute of Cardiometabolism and Nutrition, 75012 Paris, France.,Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Dorota Jeziorowska
- Sorbonne Université, UPMC Université Paris 6, UMR-S1166 ICAN, 75013 Paris, France
| | - Akshay Shah
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway
| | - Matthieu Mantecon
- Sorbonne Université, Inserm UMR S938, Saint-Antoine Research Centre, Institute of Cardiometabolism and Nutrition, 75012 Paris, France
| | - Emilie Capel
- Sorbonne Université, Inserm UMR S938, Saint-Antoine Research Centre, Institute of Cardiometabolism and Nutrition, 75012 Paris, France
| | - Marie Garcia
- Sorbonne Université, Inserm UMR S938, Saint-Antoine Research Centre, Institute of Cardiometabolism and Nutrition, 75012 Paris, France
| | - Anja Oldenburg
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway
| | - Jonas Paulsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway
| | - Jean-Sebastien Hulot
- Sorbonne Université, UPMC Université Paris 6, UMR-S1166 ICAN, 75013 Paris, France
| | - Corinne Vigouroux
- Sorbonne Université, Inserm UMR S938, Saint-Antoine Research Centre, Institute of Cardiometabolism and Nutrition, 75012 Paris, France.,AP-HP Saint-Antoine Hospital, Molecular Biology and Genetics Laboratory, Endocrinology Department, National Reference Center for Insulin Secretion and Insulin Sensitivity Rare Diseases, 75012 Paris, France
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317 Oslo, Norway.,Department of Immunology and Transfusion Medicine, Norwegian Center for Stem Cell Research, Oslo University Hospital, 0424 Oslo, Norway
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44
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Mirza AN, McKellar SA, Urman NM, Brown AS, Hollmig T, Aasi SZ, Oro AE. LAP2 Proteins Chaperone GLI1 Movement between the Lamina and Chromatin to Regulate Transcription. Cell 2019; 176:198-212.e15. [PMID: 30503211 PMCID: PMC6379078 DOI: 10.1016/j.cell.2018.10.054] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/13/2018] [Accepted: 10/26/2018] [Indexed: 12/20/2022]
Abstract
Understanding transcription factor navigation through the nucleus remains critical for developing targeted therapeutics. The GLI1 transcription factor must maintain maximal Hedgehog pathway output in basal cell carcinomas (BCCs), and we have previously shown that resistant BCCs increase GLI1 deacetylation through atypical protein kinase Cι/λ (aPKC) and HDAC1. Here we identify a lamina-associated polypeptide 2 (LAP2) isoform-dependent nuclear chaperoning system that regulates GLI1 movement between the nuclear lamina and nucleoplasm to achieve maximal activation. LAP2β forms a two-site interaction with the GLI1 zinc-finger domain and acetylation site, stabilizing an acetylation-dependent reserve on the inner nuclear membrane (INM). By contrast, the nucleoplasmic LAP2α competes with LAP2β for GLI1 while scaffolding HDAC1 to deacetylate the secondary binding site. aPKC functions to promote GLI1 association with LAP2α, promoting egress off the INM. GLI1 intranuclear trafficking by LAP2 isoforms represents a powerful signal amplifier in BCCs with implications for zinc finger-based signal transduction and therapeutics.
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Affiliation(s)
- Amar N Mirza
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Siegen A McKellar
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nicole M Urman
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alexander S Brown
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tyler Hollmig
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sumaira Z Aasi
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anthony E Oro
- Program in Epithelial Biology and Department of Dermatology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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45
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2C-BioID: An Advanced Two Component BioID System for Precision Mapping of Protein Interactomes. iScience 2018; 10:40-52. [PMID: 30500481 PMCID: PMC6263017 DOI: 10.1016/j.isci.2018.11.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 09/26/2018] [Accepted: 11/12/2018] [Indexed: 12/31/2022] Open
Abstract
The modulation of protein-protein interactions (PPIs) is an essential regulatory activity defining diverse cell functions in development and disease. BioID is an unbiased proximity-dependent biotinylation method making use of a biotin-protein ligase fused to a protein of interest and has become an important tool for mapping of PPIs within cellular contexts. We devised an advanced method, 2C-BioID, in which the biotin-protein ligase is kept separate from the protein of interest, until the two are induced to associate by the addition of a dimerizing agent. As proof of principle, we compared the interactomes of lamina-associated polypeptide 2β (LAP2β) with those of lamins A and C, using 2C- and conventional BioID. 2C-BioID greatly enhanced data robustness by facilitating the in silico elimination of non-specific interactors as well as overcoming the problems associated with aberrant protein localization. 2C-BioID therefore significantly strengthens the specificity and reliability of BioID-based interactome analysis, by the more stringent exclusion of false-positives and more efficient intracellular targeting.
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46
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Bártová E, Legartová S, Krejčí J, Řezníčková P, Kovaříková AS, Suchánková J, Fedr R, Smirnov E, Hornáček M, Raška I. Depletion of A-type lamins and Lap2α reduces 53BP1 accumulation at UV-induced DNA lesions and Lap2α protein is responsible for compactness of irradiated chromatin. J Cell Biochem 2018; 119:8146-8162. [PMID: 29923310 DOI: 10.1002/jcb.26770] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 02/02/2018] [Indexed: 12/29/2022]
Abstract
We studied how deficiency in lamins A/C and lamina-associated polypeptide 2α (Lap2α) affects DNA repair after irradiation. A-type lamins and Lap2α were not recruited to local DNA lesions and did not accumulate to γ-irradiation-induced foci (IRIF), as it is generally observed for well-known marker of DNA lesions, 53BP1 protein. At micro-irradiated chromatin of lmna double knockout (dn) and Lap2α dn cells, 53BP1 protein levels were reduced, compared to locally irradiated wild-type counterpart. Decreased levels of 53BP1 we also observed in whole populations of lmna dn and Lap2α dn cells, irradiated by UV light. We also studied distribution pattern of 53BP1 protein in a genome outside micro-irradiated region. In Lap2α deficient cells, identical fluorescence of mCherry-tagged 53BP1 protein was found at both microirradiated region and surrounding chromatin. However, a well-known marker of double strand breaks, γH2AX, was highly abundant in the lesion-surrounding genome of Lap2α deficient cells. Described changes, induced by irradiation in Lap2α dn cells, were not accompanied by cell cycle changes. In Lap2α dn cells, we additionally performed analysis by FLIM (Fluorescence Lifetime Imaging Microscopy) that showed different dynamic behavior of mCherry-tagged 53BP1 protein pools when it was compared with wild-type (wt) fibroblasts. This analysis revealed three different fractions of mCherry-53BP1 protein. Two of them showed identical exponential decay times (τ1 and τ3), but the decay rate of τ2 and amplitudes of fluorescence decays (A1-A3) were statistically different in wt and Lap2α dn fibroblasts. Moreover, γ-irradiation weakened an interaction between A-type lamins and Lap2α. Together, our results demonstrate how depletion of Lap2α affects DNA damage response (DDR) and how chromatin compactness is changed in Lap2α deficient cells exposed to radiation.
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Affiliation(s)
- Eva Bártová
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Soňa Legartová
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jana Krejčí
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Petra Řezníčková
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | | | - Jana Suchánková
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Radek Fedr
- Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
| | - Evgeny Smirnov
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | - Matúš Hornáček
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | - Ivan Raška
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
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Linker of nucleoskeleton and cytoskeleton complex proteins in cardiomyopathy. Biophys Rev 2018; 10:1033-1051. [PMID: 29869195 PMCID: PMC6082319 DOI: 10.1007/s12551-018-0431-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 05/24/2018] [Indexed: 12/21/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex couples the nuclear lamina to the cytoskeleton. The LINC complex and its associated proteins play diverse roles in cells, ranging from genome organization, nuclear morphology, gene expression, to mechanical stability. The importance of a functional LINC complex is highlighted by the large number of mutations in genes encoding LINC complex proteins that lead to skeletal and cardiac myopathies. In this review, the structure, function, and interactions between components of the LINC complex will be described. Mutations that are known to cause cardiomyopathy in patients will be discussed alongside their respective mouse models. Furthermore, future challenges for the field and emerging technologies to investigate LINC complex function will be discussed.
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Khanna R, Krishnamoorthy V, Parnaik VK. E3 ubiquitin ligase RNF123 targets lamin B1 and lamin-binding proteins. FEBS J 2018; 285:2243-2262. [PMID: 29676528 DOI: 10.1111/febs.14477] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 03/26/2018] [Accepted: 04/13/2018] [Indexed: 12/27/2022]
Abstract
Lamins are key nuclear proteins which are important for maintaining nuclear structure and function. Mutations in lamins cause a spectrum of genetic diseases termed as laminopathies. RING finger containing E3 ubiquitin ligase, RNF123, is transcriptionally upregulated in cells expressing rod domain lamin A mutations. However, the functional relevance of RNF123 in laminopathic cells is not clear. Using a mass spectrometry-based approach, we identified lamins and lamin-binding proteins retinoblastoma protein (pRb), lamina-associated polypeptide 2α (LAP2α), and emerin as RNF123-interacting proteins. We determined that RNF123 mediated the ubiquitination of these proteins and caused the proteasomal degradation of pRb, LAP2α, and lamin B1. Furthermore, these proteins were also targeted for proteasomal degradation in cells expressing lamin A rod domain mutants G232E, Q294P, and R386K. Overexpression of RNF123 resulted in delayed transit through the S-phase which was alleviated by coexpression of pRb or LAP2α. Our findings imply that RNF123-mediated ubiquitination of lamin-binding proteins may contribute to disease-causing mechanisms in laminopathies by depletion of key nuclear proteins and defects in cell cycle kinetics.
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Affiliation(s)
- Richa Khanna
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Veena K Parnaik
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
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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: 23] [Impact Index Per Article: 3.8] [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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50
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Brady GF, Kwan R, Ulintz PJ, Nguyen P, Bassirian S, Basrur V, Nesvizhskii AI, Loomba R, Omary MB. Nuclear lamina genetic variants, including a truncated LAP2, in twins and siblings with nonalcoholic fatty liver disease. Hepatology 2018; 67:1710-1725. [PMID: 28902428 PMCID: PMC5849478 DOI: 10.1002/hep.29522] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 08/15/2017] [Accepted: 09/07/2017] [Indexed: 01/03/2023]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) is becoming the major chronic liver disease in many countries. Its pathogenesis is multifactorial, but twin and familial studies indicate significant heritability, which is not fully explained by currently known genetic susceptibility loci. Notably, mutations in genes encoding nuclear lamina proteins, including lamins, cause lipodystrophy syndromes that include NAFLD. We hypothesized that variants in lamina-associated proteins predispose to NAFLD and used a candidate gene-sequencing approach to test for variants in 10 nuclear lamina-related genes in a cohort of 37 twin and sibling pairs: 21 individuals with and 53 without NAFLD. Twelve heterozygous sequence variants were identified in four lamina-related genes (ZMPSTE24, TMPO, SREBF1, SREBF2). The majority of NAFLD patients (>90%) had at least one variant compared to <40% of controls (P < 0.0001). When only insertions/deletions and changes in conserved residues were considered, the difference between the groups was similarly striking (>80% versus <25%; P < 0.0001). Presence of a lamina variant segregated with NAFLD independently of the PNPLA3 I148M polymorphism. Several variants were found in TMPO, which encodes the lamina-associated polypeptide-2 (LAP2) that has not been associated with liver disease. One of these, a frameshift insertion that generates truncated LAP2, abrogated lamin-LAP2 binding, caused LAP2 mislocalization, altered endogenous lamin distribution, increased lipid droplet accumulation after oleic acid treatment in transfected cells, and led to cytoplasmic association with the ubiquitin-binding protein p62/SQSTM1. CONCLUSION Several variants in nuclear lamina-related genes were identified in a cohort of twins and siblings with NAFLD; one such variant, which results in a truncated LAP2 protein and a dramatic phenotype in cell culture, represents an association of TMPO/LAP2 variants with NAFLD and underscores the potential importance of the nuclear lamina in NAFLD. (Hepatology 2018;67:1710-1725).
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of 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 and Department of Internal Medicine, University of Michigan
| | - Peter J. Ulintz
- Department of Computational Medicine and Bioinformatics, University of Michigan
| | - Phirum Nguyen
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego
| | - Shirin Bassirian
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego
| | - Venkatesha Basrur
- Department of Computational Medicine and Bioinformatics, University of Michigan
| | - Alexey I. Nesvizhskii
- Department of Computational Medicine and Bioinformatics, University of Michigan,Department of Pathology, University of Michigan
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan
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