1
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Biggs LC, Miroshnikova YA. Nuclear mechanotransduction on skin stem cell fate regulation. Curr Opin Cell Biol 2024; 87:102328. [PMID: 38340567 DOI: 10.1016/j.ceb.2024.102328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 02/12/2024]
Abstract
Mammalian skin is a highly dynamic and regenerative organ that has long been recognized as a mechanically active composite of tissues withstanding daily compressive and tensile forces that arise from body movement. Importantly, cell- and tissue-scale mechanical signals are critical regulators of skin morphogenesis and homeostasis. These signals are sensed at the cellular periphery and transduced by mechanosensitive proteins within the plasma membrane to the cytoskeletal networks, and eventually into the nucleus to regulate chromatin organization and gene expression. The role of each of these nodes in producing a coherent mechanoresponse at both cell- and tissue-scales is emerging. Here we focus on the key cytoplasmic and nuclear mechanosensitive structures that are critical for the mammalian skin development and homeostatic maintenance. We propose that the mechanical state of the skin, in particular of its nuclear compartment, is a critical rheostat that fine-tunes developmental and homeostatic processes essential for the proper function of the organ.
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Affiliation(s)
- Leah C Biggs
- Department of Cell and Tissue Dynamics, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany.
| | - Yekaterina A Miroshnikova
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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2
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Li Y, Zhu J, Yu Z, Li H, Jin X. The role of Lamin B2 in human diseases. Gene 2023; 870:147423. [PMID: 37044185 DOI: 10.1016/j.gene.2023.147423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 04/02/2023] [Accepted: 04/05/2023] [Indexed: 04/14/2023]
Abstract
Lamin B2 (LMNB2), on the inner side of the nuclear envelope, constitutes the nuclear skeleton by connecting with other nuclear proteins. LMNB2 is involved in a wide range of nuclear functions, including DNA replication and stability, regulation of chromatin, and nuclear stiffness. Moreover, LMNB2 regulates several cellular processes, such as tissue development, cell cycle, cellular proliferation and apoptosis, chromatin localization and stability, and DNA methylation. Besides, the influence of abnormal expression and mutations of LMNB2 has been gradually discovered in cancers and laminopathies. Therefore, this review summarizes the recent advances of LMNB2-associated biological roles in physiological or pathological conditions, with a particular emphasis on cancers and laminopathies, as well as the potential mechanism of LMNB2 in related cancers.
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Affiliation(s)
- Yuxuan Li
- Department of Hepatobiliary and Pancreatic Surgery, Ningbo Medical Center of LiHuiLi Hospital, Ningbo University, Ningbo, Zhejiang 315040, P.R. China; Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Jie Zhu
- Department of Hepatobiliary and Pancreatic Surgery, Ningbo Medical Center of LiHuiLi Hospital, Ningbo University, Ningbo, Zhejiang 315040, P.R. China; Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Zongdong Yu
- Department of Hepatobiliary and Pancreatic Surgery, Ningbo Medical Center of LiHuiLi Hospital, Ningbo University, Ningbo, Zhejiang 315040, P.R. China; Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Hong Li
- Department of Hepatobiliary and Pancreatic Surgery, Ningbo Medical Center of LiHuiLi Hospital, Ningbo University, Ningbo, Zhejiang 315040, P.R. China; Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China.
| | - Xiaofeng Jin
- Department of Hepatobiliary and Pancreatic Surgery, Ningbo Medical Center of LiHuiLi Hospital, Ningbo University, Ningbo, Zhejiang 315040, P.R. China; Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China.
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3
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Evangelisti C, Rusciano I, Mongiorgi S, Ramazzotti G, Lattanzi G, Manzoli L, Cocco L, Ratti S. The wide and growing range of lamin B-related diseases: from laminopathies to cancer. Cell Mol Life Sci 2022; 79:126. [PMID: 35132494 PMCID: PMC8821503 DOI: 10.1007/s00018-021-04084-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 12/18/2022]
Abstract
B-type lamins are fundamental components of the nuclear lamina, a complex structure that acts as a scaffold for organization and function of the nucleus. Lamin B1 and B2, the most represented isoforms, are encoded by LMNB1 and LMNB2 gene, respectively. All B-type lamins are synthesized as precursors and undergo sequential post-translational modifications to generate the mature protein. B-type lamins are involved in a wide range of nuclear functions, including DNA replication and repair, regulation of chromatin and nuclear stiffness. Moreover, lamins B1 and B2 regulate several cellular processes, such as tissue development, cell cycle, cellular proliferation, senescence, and DNA damage response. During embryogenesis, B-type lamins are essential for organogenesis, in particular for brain development. As expected from the numerous and pivotal functions of B-type lamins, mutations in their genes or fluctuations in their expression levels are critical for the onset of several diseases. Indeed, a growing range of human disorders have been linked to lamin B1 or B2, increasing the complexity of the group of diseases collectively known as laminopathies. This review highlights the recent findings on the biological role of B-type lamins under physiological or pathological conditions, with a particular emphasis on brain disorders and cancer.
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Affiliation(s)
- Camilla Evangelisti
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Isabella Rusciano
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Sara Mongiorgi
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Giulia Ramazzotti
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Giovanna Lattanzi
- CNR Institute of Molecular Genetics "Luigi Luca Cavalli-Sforza", Unit of Bologna, Bologna, Italy
- IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Lucia Manzoli
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.
| | - Lucio Cocco
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.
| | - Stefano Ratti
- Cellular Signalling Laboratory, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
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4
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Abstract
Lamins interact with a host of nuclear membrane proteins, transcription factors, chromatin regulators, signaling molecules, splicing factors, and even chromatin itself to form a nuclear subcompartment, the nuclear lamina, that is involved in a variety of cellular processes such as the governance of nuclear integrity, nuclear positioning, mitosis, DNA repair, DNA replication, splicing, signaling, mechanotransduction and -sensation, transcriptional regulation, and genome organization. Lamins are the primary scaffold for this nuclear subcompartment, but interactions with lamin-associated peptides in the inner nuclear membrane are self-reinforcing and mutually required. Lamins also interact, directly and indirectly, with peripheral heterochromatin domains called lamina-associated domains (LADs) and help to regulate dynamic 3D genome organization and expression of developmentally regulated genes.
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Affiliation(s)
- Xianrong Wong
- Laboratory of Developmental and Regenerative Biology, Skin Research Institute of Singapore, Agency for Science, Technology and Research (A∗STAR), Singapore 138648
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA
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5
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Nuclear Lamins: Key Proteins for Embryonic Development. BIOLOGY 2022; 11:biology11020198. [PMID: 35205065 PMCID: PMC8869099 DOI: 10.3390/biology11020198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 11/28/2022]
Abstract
Simple Summary The biology of a multicellular organism is extremely complex, leaving behind a realm of compound yet systematic mechanisms still to be unraveled. The nucleus is a vital cellular organelle adapted to storing and regulating the hereditary genetic information. Dysregulation of the nucleus can have profound effects on the physiology and viability of cells. This becomes extremely significant in the context of development, where the whole organism arises from a single cell, the zygote. Therefore, even a mild aberration at this stage can have profound effects on the whole organism. However, studying the function of individual nuclear components at this point is exceptionally complicated because this phase is inherently under the control of maternal factors stored in the female germ cell, the egg. Here, we focus on the lamins, as essential nuclear components, and summarize the current knowledge of their role in development. Although scientists encounter challenges working with these miniscule yet key proteins, the demand to know more is increasing gradually due to the mutations caused in lamins leading to irreversible phenotypic conditions in humans. Abstract Lamins are essential components of the nuclear envelope and have been studied for decades due to their involvement in several devastating human diseases, the laminopathies. Despite intensive research, the molecular basis behind the disease state remains mostly unclear with a number of conflicting results regarding the different cellular functions of nuclear lamins being published. The field of developmental biology is no exception. Across model organisms, the types of lamins present in early mammalian development have been contradictory over the years. Due to the long half-life of the lamin proteins, which is a maternal factor that gets carried over to the zygote after fertilization, investigators are posed with challenges to dive into the functional aspects and significance of lamins in development. Due to these technical limitations, the role of lamins in early mammalian embryos is virtually unexplored. This review aims in converging results that were obtained so far in addition to the complex functions that ceases if lamins are mutated.
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6
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Farajzadeh Valilou S, Karimzad Hagh J, Salimi Asl M, Abdi Rad I, Edizadeh M, Pooladi A. A novel biallelic LMNB2 variant in a patient with progressive myoclonus epilepsy and ataxia: A case of laminopathy. Clin Case Rep 2021; 9:e04520. [PMID: 34466237 PMCID: PMC8381754 DOI: 10.1002/ccr3.4520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/20/2021] [Accepted: 05/30/2021] [Indexed: 12/26/2022] Open
Abstract
The report of LMNB2-related progressive myoclonus epilepsy and ataxia due to missense homozygous c.473G>T variant.
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Affiliation(s)
- Saeed Farajzadeh Valilou
- Department of Medical Genetics and Sarem Cell Research Center (SCRC)Sarem Womens' HospitalTehranIran
- Medical Genetics Network (MeGeNe)Universal Scientific Education and Research Network (USERN)TehranIran
| | - Javad Karimzad Hagh
- Department of Medical Genetics and Sarem Cell Research Center (SCRC)Sarem Womens' HospitalTehranIran
- IVF CenterCuypers & Cuypers Fertility Center Heinsberger HöfeHeinsbergGermany
| | - Mohammad Salimi Asl
- Department of Medical Genetics and Sarem Cell Research Center (SCRC)Sarem Womens' HospitalTehranIran
| | - Isa Abdi Rad
- Departament of Medical GeneticsSchool of MedicineUrmia University of Medical SciencesUrmiaIran
| | - Masoud Edizadeh
- Biotechnology DepartmentSchool of MedicineLorestan University of Medical SciencesKhorramabadLorestanIran
| | - Arash Pooladi
- Cancer and Immunology Research CenterResearch Institute for Health DevelopmentKurdistan University of Medical SciencesSanandajIran
- Department of Medical GeneticsFaculty of MedicineKurdistan University of Medical SciencesSanandajIran
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7
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Chen NY, Kim PH, Tu Y, Yang Y, Heizer PJ, Young SG, Fong LG. Increased expression of LAP2β eliminates nuclear membrane ruptures in nuclear lamin-deficient neurons and fibroblasts. Proc Natl Acad Sci U S A 2021; 118:e2107770118. [PMID: 34161290 PMCID: PMC8237679 DOI: 10.1073/pnas.2107770118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects or deficiencies in nuclear lamins cause pathology in many cell types, and recent studies have implicated nuclear membrane (NM) ruptures as a cause of cell toxicity. We previously observed NM ruptures and progressive cell death in the developing brain of lamin B1-deficient mouse embryos. We also observed frequent NM ruptures and DNA damage in nuclear lamin-deficient fibroblasts. Factors modulating susceptibility to NM ruptures remain unclear, but we noted low levels of LAP2β, a chromatin-binding inner NM protein, in fibroblasts with NM ruptures. Here, we explored the apparent link between LAP2β and NM ruptures in nuclear lamin-deficient neurons and fibroblasts, and we tested whether manipulating LAP2β expression levels would alter NM rupture frequency. In cortical plate neurons of lamin B1-deficient embryos, we observed a strong correlation between low LAP2β levels and NM ruptures. We also found low LAP2β levels and frequent NM ruptures in neurons of cultured Lmnb1-/- neurospheres. Reducing LAP2β expression in Lmnb1-/- neurons with an siRNA markedly increased the NM rupture frequency (without affecting NM rupture duration), whereas increased LAP2β expression eliminated NM ruptures and reduced DNA damage. Consistent findings were observed in nuclear lamin-deficient fibroblasts. Reduced LAP2β expression increased NM ruptures, whereas increased LAP2β expression virtually abolished NM ruptures. Increased LAP2β expression nearly abolished NM ruptures in cells subjected to mechanical stress (an intervention that increases NM ruptures). Our studies showed that increasing LAP2β expression bolsters NM integrity in nuclear lamin-deficient cells and markedly reduces NM rupture frequency.
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Affiliation(s)
- Natalie Y Chen
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Paul H Kim
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Yiping Tu
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Ye Yang
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Patrick J Heizer
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, CA 90095;
- Department of Human Genetics, University of California, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, CA 90095
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, CA 90095;
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8
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Ho CY, Dreesen O. Faces of cellular senescence in skin aging. Mech Ageing Dev 2021; 198:111525. [PMID: 34166688 DOI: 10.1016/j.mad.2021.111525] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/30/2021] [Accepted: 06/20/2021] [Indexed: 02/06/2023]
Abstract
The skin is comprised of different cell types with different proliferative capacities. Skin aging occurs with chronological age and upon exposure to extrinsic factors such as photodamage. During aging, senescent cells accumulate in different compartments of the human skin, leading to impaired skin physiology. Diverse skin cell types may respond differently to senescence-inducing stimuli and it is not clear how this results in aging-associated skin phenotypes and pathologies. This review aims to examine and provide an overview of current evidence of cellular senescence in the skin. We will focus on cellular characteristics and behaviour of different skin cell types undergoing senescence in the epidermis and dermis, with a particular focus on the complex interplay between mitochondrial dysfunction, autophagy and DNA damage pathways. We will also examine how the dermis and epidermis cope with the accumulation of DNA damage during aging.
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Affiliation(s)
- Chin Yee Ho
- Skin Research Institute of Singapore, 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore
| | - Oliver Dreesen
- Skin Research Institute of Singapore, 8A Biomedical Grove, #06-06 Immunos, 138648, Singapore.
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9
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Rogerson C, Wotherspoon DJ, Tommasi C, Button RW, O'Shaughnessy RFL. Akt1-associated actomyosin remodelling is required for nuclear lamina dispersal and nuclear shrinkage in epidermal terminal differentiation. Cell Death Differ 2021; 28:1849-1864. [PMID: 33462407 PMCID: PMC8184862 DOI: 10.1038/s41418-020-00712-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 01/30/2023] Open
Abstract
Keratinocyte cornification and epidermal barrier formation are tightly controlled processes, which require complete degradation of intracellular organelles, including removal of keratinocyte nuclei. Keratinocyte nuclear destruction requires Akt1-dependent phosphorylation and degradation of the nuclear lamina protein, Lamin A/C, essential for nuclear integrity. However, the molecular mechanisms that result in complete nuclear removal and their regulation are not well defined. Post-confluent cultures of rat epidermal keratinocytes (REKs) undergo spontaneous and complete differentiation, allowing visualisation and perturbation of the differentiation process in vitro. We demonstrate that there is dispersal of phosphorylated Lamin A/C to structures throughout the cytoplasm in differentiating keratinocytes. We show that the dispersal of phosphorylated Lamin A/C is Akt1-dependent and these structures are specific for the removal of Lamin A/C from the nuclear lamina; nuclear contents and Lamin B were not present in these structures. Immunoprecipitation identified a group of functionally related Akt1 target proteins involved in Lamin A/C dispersal, including actin, which forms cytoskeletal microfilaments, Arp3, required for actin filament nucleation, and Myh9, a component of myosin IIa, a molecular motor that can translocate along actin filaments. Disruption of actin filament polymerisation, nucleation or myosin IIa activity prevented formation and dispersal of cytoplasmic Lamin A/C structures. Live imaging of keratinocytes expressing fluorescently tagged nuclear proteins showed a nuclear volume reduction step taking less than 40 min precedes final nuclear destruction. Preventing Akt1-dependent Lamin A/C phosphorylation and disrupting cytoskeletal Akt1-associated proteins prevented nuclear volume reduction. We propose keratinocyte nuclear destruction and differentiation requires myosin II activity and the actin cytoskeleton for two intermediate processes: Lamin A/C dispersal and rapid nuclear volume reduction.
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Affiliation(s)
- Clare Rogerson
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Duncan J Wotherspoon
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Cristina Tommasi
- Immunobiology and Dermatology, UCL Great Ormond Street Institute of Child Health, London, UK
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, UK
| | - Robert W Button
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ryan F L O'Shaughnessy
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
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10
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Bedrosian TA, Houtman J, Eguiguren JS, Ghassemzadeh S, Rund N, Novaresi NM, Hu L, Parylak SL, Denli AM, Randolph‐Moore L, Namba T, Gage FH, Toda T. Lamin B1 decline underlies age-related loss of adult hippocampal neurogenesis. EMBO J 2021; 40:e105819. [PMID: 33300615 PMCID: PMC7849303 DOI: 10.15252/embj.2020105819] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 10/23/2020] [Accepted: 11/09/2020] [Indexed: 02/03/2023] Open
Abstract
Neurogenesis in the adult hippocampus declines with age, a process that has been implicated in cognitive and emotional impairments. However, the mechanisms underlying this decline have remained elusive. Here, we show that the age-dependent downregulation of lamin B1, one of the nuclear lamins in adult neural stem/progenitor cells (ANSPCs), underlies age-related alterations in adult hippocampal neurogenesis. Our results indicate that higher levels of lamin B1 in ANSPCs safeguard against premature differentiation and regulate the maintenance of ANSPCs. However, the level of lamin B1 in ANSPCs declines during aging. Precocious loss of lamin B1 in ANSPCs transiently promotes neurogenesis but eventually depletes it. Furthermore, the reduction of lamin B1 in ANSPCs recapitulates age-related anxiety-like behavior in mice. Our results indicate that the decline in lamin B1 underlies stem cell aging and impacts the homeostasis of adult neurogenesis and mood regulation.
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Affiliation(s)
- Tracy A Bedrosian
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
- Institute for Genomic MedicineNationwide Children's HospitalColumbusOHUSA
| | - Judith Houtman
- Nuclear Architecture in Neural Plasticity and Aging, German Center for Neurodegenerative Diseases (DZNE)DresdenGermany
| | - Juan Sebastian Eguiguren
- Nuclear Architecture in Neural Plasticity and Aging, German Center for Neurodegenerative Diseases (DZNE)DresdenGermany
| | - Saeed Ghassemzadeh
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
| | - Nicole Rund
- Nuclear Architecture in Neural Plasticity and Aging, German Center for Neurodegenerative Diseases (DZNE)DresdenGermany
| | - Nicole M Novaresi
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
| | - Lauren Hu
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
| | - Sarah L. Parylak
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
| | - Ahmet M Denli
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
| | | | - Takashi Namba
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Neuroscience Center, HiLIFE‐Helsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Fred H Gage
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
| | - Tomohisa Toda
- Laboratory of GeneticsThe Salk Institute for Biological StudiesLa JollaCAUSA
- Nuclear Architecture in Neural Plasticity and Aging, German Center for Neurodegenerative Diseases (DZNE)DresdenGermany
- Paul F. Glenn Center for Biology of Aging Research at the Salk InstituteLa JollaCAUSA
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11
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Chen NY, Kim PH, Fong LG, Young SG. Nuclear membrane ruptures, cell death, and tissue damage in the setting of nuclear lamin deficiencies. Nucleus 2020; 11:237-249. [PMID: 32910721 PMCID: PMC7529418 DOI: 10.1080/19491034.2020.1815410] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 12/26/2022] Open
Abstract
The nuclear membranes function as a barrier to separate the cell nucleus from the cytoplasm, but this barrier can be compromised by nuclear membrane ruptures, leading to intermixing of nuclear and cytoplasmic contents. Spontaneous nuclear membrane ruptures (i.e., ruptures occurring in the absence of mechanical stress) have been observed in cultured cells, but they are more frequent in the setting of defects or deficiencies in nuclear lamins and when cells are subjected to mechanical stress. Nuclear membrane ruptures in cultured cells have been linked to DNA damage, but the relevance of ruptures to developmental or physiologic processes in vivo has received little attention. Recently, we addressed that issue by examining neuronal migration in the cerebral cortex, a developmental process that subjects the cell nucleus to mechanical stress. In the setting of lamin B1 deficiency, we observed frequent nuclear membrane ruptures in migrating neurons in the developing cerebral cortex and showed that those ruptures are likely the cause of observed DNA damage, neuronal cell death, and profound neuropathology. In this review, we discuss the physiologic relevance of nuclear membrane ruptures, with a focus on migrating neurons in cell culture and in the cerebral cortex of genetically modified mice.
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Affiliation(s)
- Natalie Y. Chen
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - Paul H. Kim
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - Loren G. Fong
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - Stephen G. Young
- Department of Medicine, University of California, Los Angeles, CA, USA
- Department of Human Genetics, University of California, Los Angeles, CA, USA
- Department of Molecular Biology Institute, University of California, Los Angeles, CA, USA
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12
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Xue Y, Razafsky D, Hodzic D, Kefalov VJ. Mislocalization of cone nuclei impairs cone function in mice. FASEB J 2020; 34:10242-10249. [PMID: 32539195 DOI: 10.1096/fj.202000568r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/16/2020] [Accepted: 05/19/2020] [Indexed: 11/11/2022]
Abstract
The nuclei of cone photoreceptors are located on the apical side of the outer nuclear layer (ONL) in vertebrate retinas. However, the functional role of this evolutionarily conserved localization of cone nuclei is unknown. We previously showed that Linkers of the Nucleoskeleton to the Cytoskeleton (LINC complexes) are essential for the apical migration of cone nuclei during development. Here, we developed an efficient genetic strategy to disrupt cone LINC complexes in mice. Experiments with animals from both sexes revealed that disrupting cone LINC complexes resulted in mislocalization of cone nuclei to the basal side of ONL in mouse retina. This, in turn, disrupted cone pedicle morphology, and appeared to reduce the efficiency of synaptic transmission from cones to bipolar cells. Although we did not observe other developmental or phototransduction defects in cones with mislocalized nuclei, their dark adaptation was impaired, consistent with a deficiency in chromophore recycling. These findings demonstrate that the apical localization of cone nuclei in the ONL is required for the timely dark adaptation and efficient synaptic transmission in cone photoreceptors.
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Affiliation(s)
- Yunlu Xue
- Department of Genetics, Harvard Medical School, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - David Razafsky
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Didier Hodzic
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Vladimir J Kefalov
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
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13
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Wong X, Stewart CL. The Laminopathies and the Insights They Provide into the Structural and Functional Organization of the Nucleus. Annu Rev Genomics Hum Genet 2020; 21:263-288. [PMID: 32428417 DOI: 10.1146/annurev-genom-121219-083616] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In recent years, our perspective on the cell nucleus has evolved from the view that it is a passive but permeable storage organelle housing the cell's genetic material to an understanding that it is in fact a highly organized, integrative, and dynamic regulatory hub. In particular, the subcompartment at the nuclear periphery, comprising the nuclear envelope and the underlying lamina, is now known to be a critical nexus in the regulation of chromatin organization, transcriptional output, biochemical and mechanosignaling pathways, and, more recently, cytoskeletal organization. We review the various functional roles of the nuclear periphery and their deregulation in diseases of the nuclear envelope, specifically the laminopathies, which, despite their rarity, provide insights into contemporary health-care issues.
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Affiliation(s)
- Xianrong Wong
- Regenerative and Developmental Biology Group, Institute of Medical Biology, Singapore 138648; ,
| | - Colin L Stewart
- Regenerative and Developmental Biology Group, Institute of Medical Biology, Singapore 138648; ,
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14
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Abstract
Genome-wide mapping of lamin-B1-genome interactions has shown that gene-poor and transcriptionally inactive genomic regions are associated with the nuclear lamina. Numerous studies have suggested that lamins, the major structural components of the nuclear lamina, play a role in global chromatin organization and gene expression. How lamins could influence the 3D genome organization and transcription from the nuclear periphery has, however, remained unclear. Our recent studies showed that lamins differentially regulate distinct lamina-associated chromatin domains (LADs) at the nuclear periphery, which can in turn influence global 3D genome organization and gene expression. In this Extra View, we discuss how by using various genomics tools, it has become possible to reveal the functions of lamins in orchestrating 3D genome organization and gene expression. Abbreviations: 3D: three dimensional; LAD: lamina-associated chromatin domain; 3C: Chromosome Conformation Capture; TAD: topologically associated domain; HiLands: Histone and lamina landscape; NL: nuclear lamina; mESC: mouse embryonic stem cell; DamID: DNA adenine methyltransferase identification;
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Affiliation(s)
- Youngjo Kim
- a Soonchunhyang Institute of Medi-Bio Science (SIMS) , Soonchunhyang University , Cheonan-si , Chungcheongnam-do , Korea
| | - Xiaobin Zheng
- b Department of Embryology , Carnegie Institution for Science , Baltimore , Maryland , USA
| | - Yixian Zheng
- b Department of Embryology , Carnegie Institution for Science , Baltimore , Maryland , USA
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15
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Martins F, Sousa J, Pereira CD, Cruz e Silva OAB, Rebelo S. Nuclear envelope dysfunction and its contribution to the aging process. Aging Cell 2020; 19:e13143. [PMID: 32291910 PMCID: PMC7253059 DOI: 10.1111/acel.13143] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 12/25/2022] Open
Abstract
The nuclear envelope (NE) is the central organizing unit of the eukaryotic cell serving as a genome protective barrier and mechanotransduction interface between the cytoplasm and the nucleus. The NE is mainly composed of a nuclear lamina and a double membrane connected at specific points where the nuclear pore complexes (NPCs) form. Physiological aging might be generically defined as a functional decline across lifespan observed from the cellular to organismal level. Therefore, during aging and premature aging, several cellular alterations occur, including nuclear‐specific changes, particularly, altered nuclear transport, increased genomic instability induced by DNA damage, and telomere attrition. Here, we highlight and discuss proteins associated with nuclear transport dysfunction induced by aging, particularly nucleoporins, nuclear transport factors, and lamins. Moreover, changes in the structure of chromatin and consequent heterochromatin rearrangement upon aging are discussed. These alterations correlate with NE dysfunction, particularly lamins’ alterations. Finally, telomere attrition is addressed and correlated with altered levels of nuclear lamins and nuclear lamina‐associated proteins. Overall, the identification of molecular mechanisms underlying NE dysfunction, including upstream and downstream events, which have yet to be unraveled, will be determinant not only to our understanding of several pathologies, but as here discussed, in the aging process.
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Affiliation(s)
- Filipa Martins
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| | - Jéssica Sousa
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| | - Cátia D. Pereira
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| | - Odete A. B. Cruz e Silva
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
- The Discoveries CTR Aveiro Portugal
| | - Sandra Rebelo
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
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16
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Role of the Nuclear Lamina in Age-Associated Nuclear Reorganization and Inflammation. Cells 2020; 9:cells9030718. [PMID: 32183360 PMCID: PMC7140666 DOI: 10.3390/cells9030718] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
Aging is characterized by the gradual loss of tissue function and integrity. Activation of inflammatory responses accelerates the deterioration of cells and tissues. Many studies have shown that alteration of the components of the nuclear lamina is associated with inflammation, both in vivo and in vitro. However, the mechanism by which the nuclear lamina regulates inflammation is largely unknown. Recent studies have suggested that the nuclear lamina regulates both organization of the three-dimensional chromatin structure at the nuclear periphery and global gene expression, such as the expression of inflammatory response genes. Here, we discuss the current updates in the research on nuclear lamina alteration, activation of inflammation, and nuclear reorganization in models of cellular senescence and organismal aging.
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17
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Identification of the Differentially Expressed Genes of Muscle Growth and Intramuscular Fat Metabolism in the Development Stage of Yellow Broilers. Genes (Basel) 2020; 11:genes11030244. [PMID: 32110997 PMCID: PMC7140879 DOI: 10.3390/genes11030244] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/10/2020] [Accepted: 02/20/2020] [Indexed: 02/04/2023] Open
Abstract
High-quality chicken meat is an important source of animal protein for humans. Gene expression profiles in breast muscle tissue were determined, aiming to explore the common regulatory genes relevant to muscle and intramuscular fat (IMF) during the developmental stage in chickens. Results show that breast muscle weight (BMW), breast meat percentage (BMP, %), and IMF (%) continuously increased with development. A total of 256 common differentially expressed genes (DEGs) during the developmental stage were screened. Among them, some genes related to muscle fiber hypertrophy were upregulated (e.g., CSRP3, LMOD2, MUSTN1, MYBPC1), but others (e.g., ACTC1, MYL1, MYL4) were downregulated from Week 3 to Week 18. During this period, expression of some DEGs related to the cells cycle (e.g., CCNB3, CCNE2, CDC20, MCM2) changed in a way that genetically suggests possible inhibitory regulation on cells number. In addition, DEGs associated with energy metabolism (e.g., ACOT9, CETP, LPIN1, DGAT2, RBP7, FBP1, PHKA1) were found to regulate IMF deposition. Our data identified and provide new insights into the common regulatory genes related to muscle growth, cell proliferation, and energy metabolism at the developmental stage in chickens.
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18
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Kumar Y, Sengupta D, Bickmore WA. Recent advances in the spatial organization of the mammalian genome. J Biosci 2020. [DOI: 10.1007/s12038-019-9968-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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19
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Heizer PJ, Yang Y, Tu Y, Kim PH, Chen NY, Hu Y, Yoshinaga Y, de Jong PJ, Vergnes L, Morales JE, Li RL, Jackson N, Reue K, Young SG, Fong LG. Deficiency in ZMPSTE24 and resulting farnesyl-prelamin A accumulation only modestly affect mouse adipose tissue stores. J Lipid Res 2020; 61:413-421. [PMID: 31941672 DOI: 10.1194/jlr.ra119000593] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/14/2020] [Indexed: 11/20/2022] Open
Abstract
Zinc metallopeptidase STE24 (ZMPSTE24) is essential for the conversion of farnesyl-prelamin A to mature lamin A, a key component of the nuclear lamina. In the absence of ZMPSTE24, farnesyl-prelamin A accumulates in the nucleus and exerts toxicity, causing a variety of disease phenotypes. By ∼4 months of age, both male and female Zmpste24 -/- mice manifest a near-complete loss of adipose tissue, but it has never been clear whether this phenotype is a direct consequence of farnesyl-prelamin A toxicity in adipocytes. To address this question, we generated a conditional knockout Zmpste24 allele and used it to create adipocyte-specific Zmpste24-knockout mice. To boost farnesyl-prelamin A levels, we bred in the "prelamin A-only" Lmna allele. Gene expression, immunoblotting, and immunohistochemistry experiments revealed that adipose tissue in these mice had decreased Zmpste24 expression along with strikingly increased accumulation of prelamin A. In male mice, Zmpste24 deficiency in adipocytes was accompanied by modest changes in adipose stores (an 11% decrease in body weight, a 23% decrease in body fat mass, and significantly smaller gonadal and inguinal white adipose depots). No changes in adipose stores were detected in female mice, likely because prelamin A expression in adipose tissue is lower in female mice. Zmpste24 deficiency in adipocytes did not alter the number of macrophages in adipose tissue, nor did it alter plasma levels of glucose, triglycerides, or fatty acids. We conclude that ZMPSTE24 deficiency in adipocytes, and the accompanying accumulation of farnesyl-prelamin A, reduces adipose tissue stores, but only modestly and only in male mice.
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Affiliation(s)
- Patrick J Heizer
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Ye Yang
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Paul H Kim
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Natalie Y Chen
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yan Hu
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yuko Yoshinaga
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Laurent Vergnes
- Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Jazmin E Morales
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Robert L Li
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Nicholas Jackson
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Karen Reue
- Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095 .,Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Loren G Fong
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
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20
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Kumar Y, Sengupta D, Bickmore W. Recent advances in the spatial organization of the mammalian genome. J Biosci 2020; 45:18. [PMID: 31965996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The mammalian genome is complex and presents a dynamic structural organization that reflects function. Organization of the genome inside the mammalian nucleus impacts all nuclear processes including but not limited to transcription, replication and repair, and in many biological contexts such as early development, differentiation and physiological adaptations. However, there is limited understating of how 3D organization of the mammalian genome regulates different nuclear processes. Recent advances in microscopy and a myriad of genomics methods -- ropelled by next-generation sequencing -- have advanced our knowledge of genome organization to a great extent. In this review, we discuss nuclear compartments in general and recent advances in the understanding of how mammalian genome is organized in these compartments with an emphasis on dynamics at the nuclear periphery.
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Affiliation(s)
- Yatendra Kumar
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Crewe Road South, Edinburgh EH42XU, UK
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21
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Chen NY, Yang Y, Weston TA, Belling JN, Heizer P, Tu Y, Kim P, Edillo L, Jonas SJ, Weiss PS, Fong LG, Young SG. An absence of lamin B1 in migrating neurons causes nuclear membrane ruptures and cell death. Proc Natl Acad Sci U S A 2019; 116:25870-25879. [PMID: 31796586 PMCID: PMC6926041 DOI: 10.1073/pnas.1917225116] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deficiencies in either lamin B1 or lamin B2 cause both defective migration of cortical neurons in the developing brain and reduced neuronal survival. The neuronal migration abnormality is explained by a weakened nuclear lamina that interferes with nucleokinesis, a nuclear translocation process required for neuronal migration. In contrast, the explanation for impaired neuronal survival is poorly understood. We hypothesized that the forces imparted on the nucleus during neuronal migration result in nuclear membrane (NM) ruptures, causing interspersion of nuclear and cytoplasmic contents-and ultimately cell death. To test this hypothesis, we bred Lmnb1-deficient mice that express a nuclear-localized fluorescent Cre reporter. Migrating neurons within the cortical plate of E18.5 Lmnb1-deficient embryos exhibited NM ruptures, evident by the escape of the nuclear-localized reporter into the cytoplasm and NM discontinuities by electron microscopy. The NM ruptures were accompanied by DNA damage and cell death. The NM ruptures were not observed in nonmigrating cells within the ventricular zone. NM ruptures, DNA damage, and cell death were also observed in cultured Lmnb1-/- and Lmnb2-/- neurons as they migrated away from neurospheres. To test whether mechanical forces on the cell nucleus are relevant to NM ruptures in migrating neurons, we examined cultured Lmnb1-/- neurons when exposed to external constrictive forces (migration into a field of tightly spaced silicon pillars). As the cells entered the field of pillars, there were frequent NM ruptures, accompanied by DNA damage and cell death.
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Affiliation(s)
- Natalie Y Chen
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Ye Yang
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Thomas A Weston
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Jason N Belling
- California NanoSystems Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Patrick Heizer
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Yiping Tu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Paul Kim
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Lovelyn Edillo
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
| | - Steven J Jonas
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Children's Discovery and Innovation Institute, University of California, Los Angeles, CA 90095
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095
| | - Paul S Weiss
- California NanoSystems Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Department of Bioengineering, University of California, Los Angeles, CA 90095
- Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095
| | - Loren G Fong
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095;
| | - Stephen G Young
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095;
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
- Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095
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22
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Allan CM, Heizer PJ, Tu Y, Sandoval NP, Jung RS, Morales JE, Sajti E, Troutman TD, Saunders TL, Cusanovich DA, Beigneux AP, Romanoski CE, Fong LG, Young SG. An upstream enhancer regulates Gpihbp1 expression in a tissue-specific manner. J Lipid Res 2019; 60:869-879. [PMID: 30598475 PMCID: PMC6446700 DOI: 10.1194/jlr.m091322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/02/2018] [Indexed: 01/22/2023] Open
Abstract
Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1), the protein that shuttles LPL to the capillary lumen, is essential for plasma triglyceride metabolism. When GPIHBP1 is absent, LPL remains stranded within the interstitial spaces and plasma triglyceride hydrolysis is impaired, resulting in severe hypertriglyceridemia. While the functions of GPIHBP1 in intravascular lipolysis are reasonably well understood, no one has yet identified DNA sequences regulating GPIHBP1 expression. In the current studies, we identified an enhancer element located ∼3.6 kb upstream from exon 1 of mouse Gpihbp1. To examine the importance of the enhancer, we used CRISPR/Cas9 genome editing to create mice lacking the enhancer (Gpihbp1Enh/Enh). Removing the enhancer reduced Gpihbp1 expression by >90% in the liver and by ∼50% in heart and brown adipose tissue. The reduced expression of GPIHBP1 was insufficient to prevent LPL from reaching the capillary lumen, and it did not lead to hypertriglyceridemia-even when mice were fed a high-fat diet. Compound heterozygotes (Gpihbp1Enh/- mice) displayed further reductions in Gpihbp1 expression and exhibited partial mislocalization of LPL (increased amounts of LPL within the interstitial spaces of the heart), but the plasma triglyceride levels were not perturbed. The enhancer element that we identified represents the first insight into DNA sequences controlling Gpihbp1 expression.
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Affiliation(s)
- Christopher M Allan
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Patrick J Heizer
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Norma P Sandoval
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Rachel S Jung
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Jazmin E Morales
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Eniko Sajti
- Department of Pediatrics, Division of Neurology, Rady Children's Hospital, University of California, San Diego, San Diego, CA 92123
| | - Ty D Troutman
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Thomas L Saunders
- University of Michigan Transgenic Animal Model Core, Department of Medicine, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Darren A Cusanovich
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721
| | - Anne P Beigneux
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095
| | - Casey E Romanoski
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721.
| | - Loren G Fong
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095.
| | - Stephen G Young
- Departments of Medicine University of California, Los Angeles, Los Angeles, CA 90095; Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095.
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23
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Maurer M, Lammerding J. The Driving Force: Nuclear Mechanotransduction in Cellular Function, Fate, and Disease. Annu Rev Biomed Eng 2019; 21:443-468. [PMID: 30916994 DOI: 10.1146/annurev-bioeng-060418-052139] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular behavior is continuously affected by microenvironmental forces through the process of mechanotransduction, in which mechanical stimuli are rapidly converted to biochemical responses. Mounting evidence suggests that the nucleus itself is a mechanoresponsive element, reacting to cytoskeletal forces and mediating downstream biochemical responses. The nucleus responds through a host of mechanisms, including partial unfolding, conformational changes, and phosphorylation of nuclear envelope proteins; modulation of nuclear import/export; and altered chromatin organization, resulting in transcriptional changes. It is unclear which of these events present direct mechanotransduction processes and which are downstream of other mechanotransduction pathways. We critically review and discuss the current evidence for nuclear mechanotransduction, particularly in the context of stem cell fate, a largely unexplored topic, and in disease, where an improved understanding of nuclear mechanotransduction is beginning to open new treatment avenues. Finally, we discuss innovative technological developments that will allow outstanding questions in the rapidly growing field of nuclear mechanotransduction to be answered.
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Affiliation(s)
- Melanie Maurer
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
| | - Jan Lammerding
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
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24
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Shevelyov YY, Ulianov SV. The Nuclear Lamina as an Organizer of Chromosome Architecture. Cells 2019; 8:E136. [PMID: 30744037 PMCID: PMC6406483 DOI: 10.3390/cells8020136] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 01/20/2023] Open
Abstract
The nuclear lamina (NL) is a meshwork of lamins and lamin-associated proteins adjoining the inner side of the nuclear envelope. In early embryonic cells, the NL mainly suppresses background transcription, whereas, in differentiated cell types, its disruption affects gene expression more severely. Normally, the NL serves as a backbone for multiple chromatin anchoring sites, thus shaping the spatial organization of chromosomes in the interphase nucleus. However, upon cell senescence, aging, or in some types of terminally differentiated cells and lamin-associated diseases, the loss of NL-chromatin tethering causes drastic alterations in chromosome architecture. Here, we provide an overview of the recent advances in the field of NL-chromatin interactions, focusing on their impact on chromatin positioning, compaction, repression, and spatial organization.
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Affiliation(s)
- Yuri Y. Shevelyov
- Department of Molecular Genetics of Cell, Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia;
| | - Sergey V. Ulianov
- Division of the Regulation of Transcription and Chromatin Dynamics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia;
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25
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Mehsen H, Boudreau V, Garrido D, Bourouh M, Larouche M, Maddox PS, Swan A, Archambault V. PP2A-B55 promotes nuclear envelope reformation after mitosis in Drosophila. J Cell Biol 2018; 217:4106-4123. [PMID: 30309980 PMCID: PMC6279390 DOI: 10.1083/jcb.201804018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 08/17/2018] [Accepted: 09/05/2018] [Indexed: 12/15/2022] Open
Abstract
As a dividing cell exits mitosis and daughter cells enter interphase, many proteins must be dephosphorylated. The protein phosphatase 2A (PP2A) with its B55 regulatory subunit plays a crucial role in this transition, but the identity of its substrates and how their dephosphorylation promotes mitotic exit are largely unknown. We conducted a maternal-effect screen in Drosophila melanogaster to identify genes that function with PP2A-B55/Tws in the cell cycle. We found that eggs that receive reduced levels of Tws and of components of the nuclear envelope (NE) often fail development, concomitant with NE defects following meiosis and in syncytial mitoses. Our mechanistic studies using Drosophila cells indicate that PP2A-Tws promotes nuclear envelope reformation (NER) during mitotic exit by dephosphorylating BAF and suggests that PP2A-Tws targets additional NE components, including Lamin and Nup107. This work establishes Drosophila as a powerful model to further dissect the molecular mechanisms of NER and suggests additional roles of PP2A-Tws in the completion of meiosis and mitosis.
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Affiliation(s)
- Haytham Mehsen
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada
| | - Vincent Boudreau
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada.,Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec, Canada
| | - Damien Garrido
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada
| | - Mohammed Bourouh
- Department of Biology, University of Windsor, Windsor, Ontario, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada.,Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec, Canada
| | - Paul S Maddox
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada
| | - Andrew Swan
- Department of Biology, University of Windsor, Windsor, Ontario, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, Canada .,Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec, Canada
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26
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Arbach HE, Harland-Dunaway M, Chang JK, Wills AE. Extreme nuclear branching in healthy epidermal cells of the Xenopus tail fin. J Cell Sci 2018; 131:jcs.217513. [PMID: 30131443 DOI: 10.1242/jcs.217513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 08/10/2018] [Indexed: 01/09/2023] Open
Abstract
Changes in nuclear morphology contribute to the regulation of complex cell properties, including differentiation and tissue elasticity. Perturbations of nuclear morphology are associated with pathologies that include progeria, cancer and muscular dystrophy. The mechanisms governing nuclear shape changes in healthy cells remain poorly understood, partially because there are few models of nuclear shape variation in healthy cells. Here, we introduce nuclear branching in epidermal fin cells of Xenopus tropicalis as a model for extreme variation of nuclear morphology in a diverse population of healthy cells. We found that nuclear branching arises within these cells and becomes more elaborate during embryonic development. These cells contain broadly distributed marks of transcriptionally active chromatin and heterochromatin, and have active cell cycles. We found that nuclear branches are disrupted by loss of filamentous actin and depend on epidermal expression of the nuclear lamina protein Lamin B1. Inhibition of nuclear branching disrupts fin morphology, suggesting that nuclear branching may be involved in fin development. This study introduces the nuclei of the Xenopus fin as a powerful new model for extreme nuclear morphology in healthy cells to complement studies of nuclear shape variation in pathological contexts.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Hannah E Arbach
- Department of Biochemistry, University of Washington, Seattle, WA 98195-3750, USA
| | | | - Jessica K Chang
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Andrea E Wills
- Department of Biochemistry, University of Washington, Seattle, WA 98195-3750, USA
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27
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Fibroblasts lacking nuclear lamins do not have nuclear blebs or protrusions but nevertheless have frequent nuclear membrane ruptures. Proc Natl Acad Sci U S A 2018; 115:10100-10105. [PMID: 30224463 DOI: 10.1073/pnas.1812622115] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The nuclear lamina, an intermediate filament meshwork lining the inner nuclear membrane, is formed by the nuclear lamins (lamins A, C, B1, and B2). Defects or deficiencies in individual nuclear lamin proteins have been reported to elicit nuclear blebs (protrusions or outpouchings of the nuclear envelope) and increase susceptibility for nuclear membrane ruptures. It is unclear, however, how a complete absence of nuclear lamins would affect nuclear envelope morphology and nuclear membrane integrity (i.e., whether nuclear membrane blebs or protrusions would occur and, if not, whether cells would be susceptible to nuclear membrane ruptures). To address these issues, we generated mouse embryonic fibroblasts (MEFs) lacking all nuclear lamins. The nuclear lamin-deficient MEFs had irregular nuclear shapes but no nuclear blebs or protrusions. Despite a virtual absence of nuclear blebs, MEFs lacking nuclear lamins had frequent, prolonged, and occasionally nonhealing nuclear membrane ruptures. By transmission electron microscopy, the inner nuclear membrane in nuclear lamin-deficient MEFs have a "wavy" appearance, and there were discrete discontinuities in the inner and outer nuclear membranes. Nuclear membrane ruptures were accompanied by a large increase in DNA damage, as judged by γ-H2AX foci. Mechanical stress increased both nuclear membrane ruptures and DNA damage, whereas minimizing transmission of cytoskeletal forces to the nucleus had the opposite effects.
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Abdelghany AM, Rezk NS, Osman MM, Hamid AI, Al-Breedy AM, Abdelsattar HA. Using Lamin B1 mRNA for the early diagnosis of hepatocellular carcinoma: a cross-sectional diagnostic accuracy study. F1000Res 2018; 7:1339. [PMID: 30467522 PMCID: PMC6208568 DOI: 10.12688/f1000research.14795.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/26/2018] [Indexed: 01/30/2023] Open
Abstract
Background: Hepatocellular carcinoma (HCC) is vital medical issue in Egypt. It accounts for 70.48% of all liver tumors among Egyptians. The aim of this study was to determine the diagnostic role of plasma levels of mRNA of lamin B1 by RT-qPCR as an early marker of HCC. Methods: This study was conducted at the Clinical Pathology Department in collaboration with the Department of Tropical Medicine and Infectious Diseases at Ain Shams University Hospitals. It included 30 patients with primary HCC and viral cirrhosis (all were hepatitis C virus-positive) (Group I), in addition to 10 patients with chronic liver diseases (Group II) and 10 healthy age- and sex-matched subjects (Group III). Group I was further classified according to the Barcelona-Clinic Liver Cancer Staging System. Serum α-fetoprotein (AFP) chemiluminescent-immunoassays and RT-qPCR analysis of plasma lamin B1 mRNA levels were performed for all participants. Results: AFP and lamin B1 significantly elevated in patients with HCC compared to those in the other studied groups. AFP and lamin B1 status could discriminate group I from group II and III. A significant increase was found among the three Barcelona stages with regards to AFP and lamin B1 levels. A significant decrease was found between group II and stage 0, A and B with regards to AFP and lamin B1. Lamin B1 and AFP could both differentiate HCC patients with one tumor nodule (T1) from those with two or more tumor nodules (T2&Tm), as well as between those with tumor sizes >3 cm and ≤3 cm. Conclusion: Measurement of lamin B1 mRNA is recommended in patients with chronic liver disease with normal serum AFP, especially in known cirrhotic patients that deteriorate rapidly without any apparent etiology.
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Affiliation(s)
- Amani M. Abdelghany
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Nasser Sadek Rezk
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Mona Mostafa Osman
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Amira I. Hamid
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Ashraf Mohammad Al-Breedy
- Department of Tropical Medicine and Infectious Diseases, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Hoda A. Abdelsattar
- Department of Clinical Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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29
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Brady GF, Kwan R, Cunha JB, Elenbaas JS, Omary MB. Lamins and Lamin-Associated Proteins in Gastrointestinal Health and Disease. Gastroenterology 2018; 154:1602-1619.e1. [PMID: 29549040 PMCID: PMC6038707 DOI: 10.1053/j.gastro.2018.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/04/2018] [Accepted: 03/06/2018] [Indexed: 02/07/2023]
Abstract
The nuclear lamina is a multi-protein lattice composed of A- and B-type lamins and their associated proteins. This protein lattice associates with heterochromatin and integral inner nuclear membrane proteins, providing links among the genome, nucleoskeleton, and cytoskeleton. In the 1990s, mutations in EMD and LMNA were linked to Emery-Dreifuss muscular dystrophy. Since then, the number of diseases attributed to nuclear lamina defects, including laminopathies and other disorders, has increased to include more than 20 distinct genetic syndromes. Studies of patients and mouse genetic models have pointed to important roles for lamins and their associated proteins in the function of gastrointestinal organs, including liver and pancreas. We review the interactions and functions of the lamina in relation to the nuclear envelope and genome, the ways in which its dysfunction is thought to contribute to human disease, and possible avenues for targeted therapies.
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Affiliation(s)
- Graham F. Brady
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,To whom correspondence should be addressed: University of Michigan Medical School, Division of Gastroenterology, Department of Internal Medicine, 1137 Catherine St., Ann Arbor, MI 48109-5622.
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Juliana Bragazzi Cunha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jared S. Elenbaas
- Medical Scientist Training Program, Washington University, St Louis, Missouri
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan,Ǻbo Akademi University, Turku, Finland
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Lukášová E, Kovařík A, Kozubek S. Consequences of Lamin B1 and Lamin B Receptor Downregulation in Senescence. Cells 2018; 7:cells7020011. [PMID: 29415520 PMCID: PMC5850099 DOI: 10.3390/cells7020011] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 01/28/2023] Open
Abstract
Anchoring of heterochromatin to the nuclear envelope appears to be an important process ensuring the spatial organization of the chromatin structure and genome function in eukaryotic nuclei. Proteins of the inner nuclear membrane (INM) mediating these interactions are able to recognize lamina-associated heterochromatin domains (termed LAD) and simultaneously bind either lamin A/C or lamin B1. One of these proteins is the lamin B receptor (LBR) that binds lamin B1 and tethers heterochromatin to the INM in embryonic and undifferentiated cells. It is replaced by lamin A/C with specific lamin A/C binding proteins at the beginning of cell differentiation and in differentiated cells. Our functional experiments in cancer cell lines show that heterochromatin in cancer cells is tethered to the INM by LBR, which is downregulated together with lamin B1 at the onset of cell transition to senescence. The downregulation of these proteins in senescent cells leads to the detachment of centromeric repetitive sequences from INM, their relocation to the nucleoplasm, and distension. In cells, the expression of LBR and LB1 is highly coordinated as evidenced by the reduction of both proteins in LBR shRNA lines. The loss of the constitutive heterochromatin structure containing LADs results in changes in chromatin architecture and genome function and can be the reason for the permanent loss of cell proliferation in senescence.
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Affiliation(s)
- Emilie Lukášová
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
- Department of Molecular Epigenetics, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
| | - Aleš Kovařík
- Department of Molecular Epigenetics, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
| | - Stanislav Kozubek
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
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31
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Rogerson C, Bergamaschi D, O'Shaughnessy RFL. Uncovering mechanisms of nuclear degradation in keratinocytes: A paradigm for nuclear degradation in other tissues. Nucleus 2018; 9:56-64. [PMID: 29205081 PMCID: PMC5973266 DOI: 10.1080/19491034.2017.1412027] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic nuclei are essential organelles, storing the majority of the cellular DNA, comprising the site of most DNA and RNA synthesis, controlling gene expression and therefore regulating cellular function. The majority of mammalian cells retain their nucleus throughout their lifetime, however, in three mammalian tissues the nucleus is entirely removed and its removal is essential for cell function. Lens fibre cells, erythroblasts and epidermal keratinocytes all lose their nucleus in the terminal differentiation pathways of these cell types. However, relatively little is known about the pathways that lead to complete nuclear removal and about how these pathways are regulated. In this review, we aim to discuss the current understanding of nuclear removal mechanisms in these three cell types and expand upon how recent studies into nuclear degradation in keratinocytes, an easily accessible experimental model, could contribute to a wider understanding of these molecular mechanisms in both health and pathology.
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Affiliation(s)
- Clare Rogerson
- a Centre for Cell Biology and Cutaneous Research , Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London , London , UK
| | - Daniele Bergamaschi
- a Centre for Cell Biology and Cutaneous Research , Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London , London , UK
| | - Ryan F L O'Shaughnessy
- a Centre for Cell Biology and Cutaneous Research , Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London , London , UK
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Rapisarda V, Malashchuk I, Asamaowei IE, Poterlowicz K, Fessing MY, Sharov AA, Karakesisoglou I, Botchkarev VA, Mardaryev A. p63 Transcription Factor Regulates Nuclear Shape and Expression of Nuclear Envelope-Associated Genes in Epidermal Keratinocytes. J Invest Dermatol 2017; 137:2157-2167. [PMID: 28595999 PMCID: PMC5610935 DOI: 10.1016/j.jid.2017.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/20/2017] [Accepted: 05/01/2017] [Indexed: 01/07/2023]
Abstract
The maintenance of a proper nuclear architecture and three-dimensional organization of the genes, enhancer elements, and transcription machinery plays an essential role in tissue development and regeneration. Here we show that in the developing skin, epidermal progenitor cells of mice lacking p63 transcription factor display alterations in the nuclear shape accompanied by a marked decrease in expression of several nuclear envelope-associated components (Lamin B1, Lamin A/C, Sun1, Nesprin-3, Plectin) compared with controls. Furthermore, chromatin immunoprecipitation-quantitative PCR assay showed enrichment of p63 on Sun1, Syne3, and Plec promoters, suggesting them as p63 targets. Alterations in the nuclei shape and expression of nuclear envelope-associated proteins were accompanied by altered distribution patterns of the repressive histone marks trimethylation on lysine 27 of histone H3, trimethylation on lysine 9 of histone H3, and heterochromatin protein 1-alpha in p63-null keratinocytes. These changes were also accompanied by downregulation of the transcriptional activity and relocation of the keratinocyte-specific gene loci away from the sites of active transcription toward the heterochromatin-enriched repressive nuclear compartments in p63-null cells. These data demonstrate functional links between the nuclear envelope organization, chromatin architecture, and gene expression in keratinocytes and suggest nuclear envelope-associated genes as important targets mediating p63-regulated gene expression program in the epidermis.
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Key Words
- cc, chromocenter
- chip-qpcr, chromatin immunoprecipitation-quantitative pcr
- h3k9me3, trimethylation on lysine 9 of histone h3
- h3k27me3, trimethylation on lysine 27 of histone h3
- ktyi, keratin type i
- ktyii, keratin type ii
- pmk, primary mouse keratinocyte
- if, intermediate filament
- nm, nuclear membrane
- ne, nuclear envelope
- wt, wild-type
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Affiliation(s)
| | - Igor Malashchuk
- Centre for Skin Sciences, University of Bradford, Bradford, UK
| | | | | | | | - Andrey A Sharov
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA
| | | | - Vladimir A Botchkarev
- Centre for Skin Sciences, University of Bradford, Bradford, UK; Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA.
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Mahajani S, Giacomini C, Marinaro F, De Pietri Tonelli D, Contestabile A, Gasparini L. Lamin B1 levels modulate differentiation into neurons during embryonic corticogenesis. Sci Rep 2017; 7:4897. [PMID: 28687747 PMCID: PMC5501862 DOI: 10.1038/s41598-017-05078-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/24/2017] [Indexed: 01/10/2023] Open
Abstract
Lamin B1, a key component of the nuclear lamina, plays an important role in brain development. Ablation of endogenous Lamin B1 (Lmnb1) in the mouse strongly impairs embryonic brain development and corticogenesis. However, the mechanisms underlying these neurodevelopmental effects are unknown. Here, we report that Lamin B1 levels modulate the differentiation of murine neural stem cells (NSCs) into neurons and astroglial-like cells. In vitro, endogenous Lmnb1 depletion favors NSC differentiation into glial fibrillar acidic protein (GFAP)-immunoreactive cells over neurons, while overexpression of human Lamin B1 (LMNB1) increases the proportion of neurons. In Lmnb1-null embryos, neurogenesis is reduced, while in vivo Lmnb1 silencing in mouse embryonic brain by in utero electroporation of a specific Lmnb1 sh-RNA results in aberrant cortical positioning of neurons and increased expression of the astrocytic marker GFAP in the cortex of 7-day old pups. Together, these results indicate that finely tuned levels of Lamin B1 are required for NSC differentiation into neurons, proper expression of the astrocytic marker GFAP and corticogenesis.
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Affiliation(s)
- Sameehan Mahajani
- Dept. of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
- Universitaetsmedizin Goettingen, Waldweg 33, Goettingen, 37073, Germany
| | - Caterina Giacomini
- Dept. of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
- Division of Cancer Studies, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
| | - Federica Marinaro
- Dept. of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | | | - Andrea Contestabile
- Dept. of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Laura Gasparini
- Dept. of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy.
- Abbvie Deutschland GmbH & Co, Knollstr, Ludwigshafen, 67061, Germany.
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Makarova AM, Pasta S, Watson G, Shackleton C, Epstein EH. Attenuation of UVR-induced vitamin D 3 synthesis in a mouse model deleted for keratinocyte lathosterol 5-desaturase. J Steroid Biochem Mol Biol 2017; 171:187-194. [PMID: 28330720 DOI: 10.1016/j.jsbmb.2017.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 02/27/2017] [Accepted: 03/18/2017] [Indexed: 12/31/2022]
Abstract
The lower risk of some internal cancers at lower latitudes has been linked to greater sun exposure and consequent higher levels of ultraviolet radiation (UVR)-produced vitamin D3 (D3). To separate the experimental effects of sunlight and of all forms of D3, a mouse in which UVR does not produce D3 would be useful. To this end we have generated mice carrying a modified allele of sterol C5-desaturase (Sc5d), the gene encoding the enzyme that converts lathosterol to 7-dehydrocholesterol (7-DHC), such that Sc5d expression can be inactivated using the Cre/lox site-specific recombination system. By crossing to mice with tissue-specific expression of Cre or CreER2 (Cre/estrogen receptor), we generated two lines of transgenic mice. One line has constitutive keratinocyte-specific inactivation of Sc5d (Sc5dk14KO). The other line (Sc5dk14KOi) has tamoxifen-inducible keratinocyte-specific inactivation of Sc5d. Mice deleted for keratinocyte Sc5d lose the ability to increase circulating D3 following UVR exposure of the skin. Thus, unlike in control mice, acute UVR exposure did not affect circulating D3 level in inducible Sc5dk14KOi mice. Keratinocyte-specific inactivation of Sc5d was proven by sterol measurement in hair - in control animals lathosterol and cholesta-7,24-dien-3β-ol, the target molecules of SC5D in the sterol biosynthetic pathways, together constituted a mean of 10% of total sterols; in the conditional knockout mice these sterols constituted a mean of 56% of total sterols. The constitutive knockout mice had an even greater increase, with lathosterol and cholesta-7,24-dien-3β-ol accounting for 80% of total sterols. In conclusion, the dominant presence of the 7-DHC precursors in hair of conditional animals and the lack of increased circulating D3 following exposure to UVR reflect attenuated production of the D3 photochemical precursor 7-DHC and, consequently, of D3 itself. These animals provide a useful new tool for investigating the role of D3 in UVR-induced physiological effects and, more broadly, for investigations of the cholesterol synthetic pathway in the skin and other targeted tissues.
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Affiliation(s)
- Anastasia M Makarova
- UCSF Benioff Children's Hospital Oakland Research Institute (CHORI), Oakland, CA, USA
| | - Saloni Pasta
- UCSF Benioff Children's Hospital Oakland Research Institute (CHORI), Oakland, CA, USA
| | - Gordon Watson
- UCSF Benioff Children's Hospital Oakland Research Institute (CHORI), Oakland, CA, USA
| | - Cedric Shackleton
- UCSF Benioff Children's Hospital Oakland Research Institute (CHORI), Oakland, CA, USA; Institute of Metabolism and Systems Research (IMSR), College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Ervin H Epstein
- UCSF Benioff Children's Hospital Oakland Research Institute (CHORI), Oakland, CA, USA.
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35
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Allan CM, Jung CJ, Larsson M, Heizer PJ, Tu Y, Sandoval NP, Dang TLP, Jung RS, Beigneux AP, de Jong PJ, Fong LG, Young SG. Mutating a conserved cysteine in GPIHBP1 reduces amounts of GPIHBP1 in capillaries and abolishes LPL binding. J Lipid Res 2017; 58:1453-1461. [PMID: 28476858 DOI: 10.1194/jlr.m076943] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/04/2017] [Indexed: 12/22/2022] Open
Abstract
Mutation of conserved cysteines in proteins of the Ly6 family cause human disease-chylomicronemia in the case of glycosylphosphatidylinositol-anchored HDL binding protein 1 (GPIHBP1) and paroxysmal nocturnal hemoglobinuria in the case of CD59. A mutation in a conserved cysteine in CD59 prevented the protein from reaching the surface of blood cells. In contrast, mutation of conserved cysteines in human GPIHBP1 had little effect on GPIHBP1 trafficking to the surface of cultured CHO cells. The latter findings were somewhat surprising and raised questions about whether CHO cell studies accurately model the fate of mutant GPIHBP1 proteins in vivo. To explore this concern, we created mice harboring a GPIHBP1 cysteine mutation (p.C63Y). The p.C63Y mutation abolished the ability of mouse GPIHBP1 to bind LPL, resulting in severe chylomicronemia. The mutant GPIHBP1 was detectable by immunohistochemistry on the surface of endothelial cells, but the level of expression was ∼70% lower than in WT mice. The mutant GPIHBP1 protein in mouse tissues was predominantly monomeric. We conclude that mutation of a conserved cysteine in GPIHBP1 abolishes the ability of GPIHBP1 to bind LPL, resulting in mislocalization of LPL and severe chylomicronemia. The mutation reduced but did not eliminate GPIHBP1 on the surface of endothelial cells in vivo.
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Affiliation(s)
- Christopher M Allan
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Cris J Jung
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Mikael Larsson
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Patrick J Heizer
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Norma P Sandoval
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Tiffany Ly P Dang
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Rachel S Jung
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Anne P Beigneux
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095.
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Loren G Fong
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095.
| | - Stephen G Young
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095; Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095.
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Gigante CM, Dibattista M, Dong FN, Zheng X, Yue S, Young SG, Reisert J, Zheng Y, Zhao H. Lamin B1 is required for mature neuron-specific gene expression during olfactory sensory neuron differentiation. Nat Commun 2017; 8:15098. [PMID: 28425486 PMCID: PMC5411488 DOI: 10.1038/ncomms15098] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 02/28/2017] [Indexed: 01/29/2023] Open
Abstract
B-type lamins are major constituents of the nuclear lamina in all metazoan cells, yet have specific roles in the development of certain cell types. Although they are speculated to regulate gene expression in developmental contexts, a direct link between B-type lamins and developmental gene expression in an in vivo system is currently lacking. Here, we identify lamin B1 as a key regulator of gene expression required for the formation of functional olfactory sensory neurons. By using targeted knockout in olfactory epithelial stem cells in adult mice, we show that lamin B1 deficient neurons exhibit attenuated response to odour stimulation. This deficit can be explained by decreased expression of genes involved in mature neuron function, along with increased expression of genes atypical of the olfactory lineage. These results support that the broadly expressed lamin B1 regulates expression of a subset of genes involved in the differentiation of a specific cell type.
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Affiliation(s)
- Crystal M. Gigante
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
| | - Michele Dibattista
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104, USA
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari ‘A. Moro', Bari 70121, Italy
| | - Frederick N. Dong
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Xiaobin Zheng
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
| | - Sibiao Yue
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
| | - Stephen G. Young
- Department of Medicine, Molecular Biology Institute and Department of Human Genetics, University of California, Los Angeles, California 90095, USA
| | - Johannes Reisert
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104, USA
| | - Yixian Zheng
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
| | - Haiqing Zhao
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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Razafsky D, Ward C, Potter C, Zhu W, Xue Y, Kefalov VJ, Fong LG, Young SG, Hodzic D. Lamin B1 and lamin B2 are long-lived proteins with distinct functions in retinal development. Mol Biol Cell 2016; 27:1928-37. [PMID: 27075175 PMCID: PMC4907726 DOI: 10.1091/mbc.e16-03-0143] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/06/2016] [Accepted: 04/08/2016] [Indexed: 11/11/2022] Open
Abstract
Lamin B1 and lamin B2 are essential building blocks of the nuclear lamina, a filamentous meshwork lining the nucleoplasmic side of the inner nuclear membrane. Deficiencies in lamin B1 and lamin B2 impair neurodevelopment, but distinct functions for the two proteins in the development and homeostasis of the CNS have been elusive. Here we show that embryonic depletion of lamin B1 in retinal progenitors and postmitotic neurons affects nuclear integrity, leads to the collapse of the laminB2 meshwork, impairs neuronal survival, and markedly reduces the cellularity of adult retinas. In stark contrast, a deficiency of lamin B2 in the embryonic retina has no obvious effect on lamin B1 localization or nuclear integrity in embryonic retinas, suggesting that lamin B1, but not lamin B2, is strictly required for nucleokinesis during embryonic neurogenesis. However, the absence of lamin B2 prevents proper lamination of adult retinal neurons, impairs synaptogenesis, and reduces cone photoreceptor survival. We also show that lamin B1 and lamin B2 are extremely long-lived proteins in rod and cone photoreceptors. OF interest, a complete absence of both proteins during postnatal life has little or no effect on the survival and function of cone photoreceptors.
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Affiliation(s)
- David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Candace Ward
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Chloe Potter
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Wanqiu Zhu
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Yunlu Xue
- Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095 Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095 Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
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Allan CM, Procaccia S, Tran D, Tu Y, Barnes RH, Larsson M, Allan BB, Young LC, Hong C, Tontonoz P, Fong LG, Young SG, Beigneux AP. Palmoplantar Keratoderma in Slurp2-Deficient Mice. J Invest Dermatol 2015; 136:436-443. [PMID: 26967477 PMCID: PMC4789766 DOI: 10.1016/j.jid.2015.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/29/2015] [Accepted: 10/12/2015] [Indexed: 01/13/2023]
Abstract
SLURP1, a member of the Ly6 protein family, is secreted by suprabasal keratinocytes. Mutations in SLURP1 cause a palmoplantar keratoderma (PPK) known as mal de Meleda. Another secreted Ly6 protein, SLURP2, is encoded by a gene located ~20 kb downstream from SLURP1. SLURP2 is produced by suprabasal keratinocytes. To investigate the importance of SLURP2, we first examined Slurp2 knockout mice in which exon 2–3 sequences had been replaced with lacZ and neo cassettes. Slurp2−/− mice exhibited hyperkeratosis on the volar surface of the paws (i.e., PPK), increased keratinocyte proliferation, and an accumulation of lipid droplets in the stratum corneum. They also exhibited reduced body weight and hind limb clasping. These phenotypes are very similar to those of Slurp1−/− mice. To solidify a link between Slurp2 deficiency and PPK and to be confident that the disease phenotypes in Slurp2−/− mice were not secondary to the effects of the lacZ and neo cassettes on Slurp1 expression, we created a new line of Slurp2 knockout mice (Slurp2X−/−) in which Slurp2 was inactivated with a simple nonsense mutation. Slurp2X−/− mice exhibited the same disease phenotypes. Thus, Slurp2 deficiency and Slurp1 deficiencies cause the same disease phenotypes.
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Affiliation(s)
- Christopher M Allan
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Shiri Procaccia
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Deanna Tran
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Yiping Tu
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Richard H Barnes
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Mikael Larsson
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Bernard B Allan
- Department of Molecular Biology, Genentech, South San Francisco, California, USA
| | - Lorraine C Young
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Cynthia Hong
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA; Howard Hughes Medical Institute, University of California, Los Angeles, California, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA; Howard Hughes Medical Institute, University of California, Los Angeles, California, USA
| | - Loren G Fong
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
| | - Stephen G Young
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
| | - Anne P Beigneux
- Department of Medicine, Divisions of Cardiology and Dermatology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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Abstract
Recent studies show that nuclear lamins, the type V intermediate filament proteins, are required for proper building of at least some organs. As the major structural components of the nuclear lamina found underneath the inner nuclear membranes, lamins are ubiquitously expressed in all animal cells. How the broadly expressed lamins support the building of specific tissues is not understood. By studying Drosophila testis, we have uncovered a mechanism by which lamin-B functions in the cyst stem cell (CySC) and its differentiated cyst cell, the cell types known to form the niche/microenvironment for the germline stem cells (GSC) and the developing germ line, to ensure testis organogenesis (1). In this extra view, we discuss some remaining questions and the implications of our findings in the understanding of how the ubiquitous nuclear lamina regulates tissue building in a context-dependent manner.
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Affiliation(s)
- Haiyang Chen
- a Department of Embryology; Carnegie Institution for Science; Baltimore, MD USA
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Camozzi D, Capanni C, Cenni V, Mattioli E, Columbaro M, Squarzoni S, Lattanzi G. Diverse lamin-dependent mechanisms interact to control chromatin dynamics. Focus on laminopathies. Nucleus 2015; 5:427-40. [PMID: 25482195 PMCID: PMC4164485 DOI: 10.4161/nucl.36289] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Interconnected functional strategies govern chromatin dynamics in eukaryotic cells. In this context, A and B type lamins, the nuclear intermediate filaments, act on diverse platforms involved in tissue homeostasis. On the nuclear side, lamins elicit large scale or fine chromatin conformational changes, affect DNA damage response factors and transcription factor shuttling. On the cytoplasmic side, bridging-molecules, the LINC complex, associate with lamins to coordinate chromatin dynamics with cytoskeleton and extra-cellular signals.
Consistent with such a fine tuning, lamin mutations and/or defects in their expression or post-translational processing, as well as mutations in lamin partner genes, cause a heterogeneous group of diseases known as laminopathies. They include muscular dystrophies, cardiomyopathy, lipodystrophies, neuropathies, and progeroid syndromes. The study of chromatin dynamics under pathological conditions, which is summarized in this review, is shedding light on the complex and fascinating role of the nuclear lamina in chromatin regulation.
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Affiliation(s)
- Daria Camozzi
- a CNR Institute for Molecular Genetics; Unit of Bologna and SC Laboratory of Musculoskeletal Cell Biology; Rizzoli Orthopedic Institute; Bologna, Italy
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Sola Carvajal A, McKenna T, Wallén Arzt E, Eriksson M. Overexpression of Lamin B Receptor Results in Impaired Skin Differentiation. PLoS One 2015; 10:e0128917. [PMID: 26053873 PMCID: PMC4459694 DOI: 10.1371/journal.pone.0128917] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/01/2015] [Indexed: 01/11/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a rare segmental progeroid disorder commonly caused by a point mutation in the LMNA gene that results in the increased activation of an intra-exonic splice site and the production of a truncated lamin A protein, named progerin. In our previous work, induced murine epidermal expression of this specific HGPS LMNA mutation showed impaired keratinocyte differentiation and upregulated lamin B receptor (LBR) expression in suprabasal keratinocytes. Here, we have developed a novel transgenic animal model with induced overexpression of LBR in the interfollicular epidermis. LBR overexpression resulted in epidermal hypoplasia, along with the downregulation and mislocalization of keratin 10, suggesting impaired keratinocyte differentiation. Increased LBR expression in basal and suprabasal cells did not coincide with increased proliferation. Similar to our previous report of HGPS mice, analyses of γH2AX, a marker of DNA double-strand breaks, revealed an increased number of keratinocytes with multiple foci in LBR-overexpressing mice compared with wild-type mice. In addition, suprabasal LBR-positive cells showed densely condensed and peripherally localized chromatin. Our results show a moderate skin differentiation phenotype, which indicates that upregulation of LBR is not the sole contributor to the HGPS phenotype.
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Affiliation(s)
- Agustín Sola Carvajal
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Tomás McKenna
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Emelie Wallén Arzt
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
| | - Maria Eriksson
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, SE-141 83, Sweden
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Amendola M, van Steensel B. Nuclear lamins are not required for lamina-associated domain organization in mouse embryonic stem cells. EMBO Rep 2015; 16:610-7. [PMID: 25784758 DOI: 10.15252/embr.201439789] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/16/2015] [Indexed: 11/09/2022] Open
Abstract
In mammals, the nuclear lamina interacts with hundreds of large genomic regions, termed lamina-associated domains (LADs) that are generally in a transcriptionally repressed state. Lamins form the major structural component of the lamina and have been reported to bind DNA and chromatin. Here, we systematically evaluate whether lamins are necessary for the LAD organization in murine embryonic stem cells. Surprisingly, removal of essentially all lamins does not have any detectable effect on the genome-wide interaction pattern of chromatin with emerin, a marker of the inner nuclear membrane. This suggests that other components of the lamina mediate these interactions.
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Affiliation(s)
- Mario Amendola
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
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Butin-Israeli V, Adam SA, Jain N, Otte GL, Neems D, Wiesmüller L, Berger SL, Goldman RD. Role of lamin b1 in chromatin instability. Mol Cell Biol 2015; 35:884-98. [PMID: 25535332 PMCID: PMC4323489 DOI: 10.1128/mcb.01145-14] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/01/2014] [Accepted: 12/18/2014] [Indexed: 01/14/2023] Open
Abstract
Nuclear lamins play important roles in the organization and structure of the nucleus; however, the specific mechanisms linking lamin structure to nuclear functions are poorly defined. We demonstrate that reducing nuclear lamin B1 expression by short hairpin RNA-mediated silencing in cancer cell lines to approximately 50% of normal levels causes a delay in the cell cycle and accumulation of cells in early S phase. The S phase delay appears to be due to the stalling and collapse of replication forks. The double-strand DNA breaks resulting from replication fork collapse were inefficiently repaired, causing persistent DNA damage signaling and the assembly of extensive repair foci on chromatin. The expression of multiple factors involved in DNA replication and repair by both nonhomologous end joining and homologous repair is misregulated when lamin B1 levels are reduced. We further demonstrate that lamin B1 interacts directly with the promoters of some genes associated with DNA damage response and repair, including BRCA1 and RAD51. Taken together, the results suggest that the maintenance of lamin B1 levels is required for DNA replication and repair through regulation of the expression of key factors involved in these essential nuclear functions.
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Affiliation(s)
- Veronika Butin-Israeli
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Stephen A Adam
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Nikhil Jain
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gabriel L Otte
- Epigenetics Program, Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Daniel Neems
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany
| | - Shelly L Berger
- Epigenetics Program, Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Gruenbaum Y, Foisner R. Lamins: nuclear intermediate filament proteins with fundamental functions in nuclear mechanics and genome regulation. Annu Rev Biochem 2015; 84:131-64. [PMID: 25747401 DOI: 10.1146/annurev-biochem-060614-034115] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lamins are intermediate filament proteins that form a scaffold, termed nuclear lamina, at the nuclear periphery. A small fraction of lamins also localize throughout the nucleoplasm. Lamins bind to a growing number of nuclear protein complexes and are implicated in both nuclear and cytoskeletal organization, mechanical stability, chromatin organization, gene regulation, genome stability, differentiation, and tissue-specific functions. The lamin-based complexes and their specific functions also provide insights into possible disease mechanisms for human laminopathies, ranging from muscular dystrophy to accelerated aging, as observed in Hutchinson-Gilford progeria and atypical Werner syndromes.
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Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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45
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Camps J, Erdos MR, Ried T. The role of lamin B1 for the maintenance of nuclear structure and function. Nucleus 2015; 6:8-14. [PMID: 25602590 PMCID: PMC4615282 DOI: 10.1080/19491034.2014.1003510] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 12/22/2022] Open
Abstract
Lamins constitute an integral structural component of the nuclear lamina. However, their impact on the structure and stability of chromosome territories, and on the regulation of gene expression is explored to a lesser extent. By 3D-FISH, Camps and colleagues showed that lamin B1 (LMNB1) is required for proper chromosome condensation in interphase nuclei, and deficiency of LMNB1 triggers the relocation of the epigenetic mark of facultative heterochromatin, H3K27me3, toward the interior of the nucleus. Additionally, LMNB1 repression slowed cellular growth due to S-phase delays and increased genomic instability. Finally, silencing of LMNB1 resulted in enlarged nuclear speckles and in extensive changes in alternative splicing of multiple genes. Altogether, the data suggest a central role of LMNB1 for the condensation of chromosome territories, for the distribution of heterochromatin, and for the regulation of gene expression and splicing.
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Affiliation(s)
- Jordi Camps
- Laboratory of Gastrointestinal and Pancreatic Oncology; Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Hospital Clínic of Barcelona, CIBERehd; Barcelona, Spain
| | - Michael R Erdos
- Genome Technology Branch; National Human Genome Research Institute; National Institutes of Health; Bethesda, MD USA
| | - Thomas Ried
- Section of Cancer Genomics, Genetics Branch; National Cancer Institute; National Institutes of Health; Bethesda, MD USA
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46
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An absence of nuclear lamins in keratinocytes leads to ichthyosis, defective epidermal barrier function, and intrusion of nuclear membranes and endoplasmic reticulum into the nuclear chromatin. Mol Cell Biol 2014; 34:4534-44. [PMID: 25312645 DOI: 10.1128/mcb.00997-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
B-type lamins (lamins B1 and B2) have been considered to be essential for many crucial functions in the cell nucleus (e.g., DNA replication and mitotic spindle formation). However, this view has been challenged by the observation that an absence of both B-type lamins in keratinocytes had no effect on cell proliferation or the development of skin and hair. The latter findings raised the possibility that the functions of B-type lamins are subserved by lamins A and C. To explore that idea, we created mice lacking all nuclear lamins in keratinocytes. Those mice developed ichthyosis and a skin barrier defect, which led to death from dehydration within a few days after birth. Microscopy of nuclear-lamin-deficient skin revealed hyperkeratosis and a disordered stratum corneum with an accumulation of neutral lipid droplets; however, BrdU incorporation into keratinocytes was normal. Skin grafting experiments confirmed the stratum corneum abnormalities and normal BrdU uptake. Interestingly, the absence of nuclear lamins in keratinocytes resulted in an interspersion of nuclear/endoplasmic reticulum membranes with the chromatin. Thus, a key function of the nuclear lamina is to serve as a "fence" and prevent the incursion of cytoplasmic organelles into the nuclear chromatin.
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47
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Lee JM, Jung HJ, Fong LG, Young SG. Do lamin B1 and lamin B2 have redundant functions? Nucleus 2014; 5:287-92. [PMID: 25482116 PMCID: PMC4152341 DOI: 10.4161/nucl.29615] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/12/2014] [Accepted: 06/16/2014] [Indexed: 12/29/2022] Open
Abstract
Lamins B1 and B2 have a high degree of sequence similarity and are widely expressed from the earliest stages of development. Studies of Lmnb1 and Lmnb2 knockout mice revealed that both of the B-type lamins are crucial for neuronal migration in the developing brain. These observations naturally posed the question of whether the two B-type lamins might play redundant functions in the development of the brain. To explore that issue, Lee and coworkers generated "reciprocal knock-in mice" (knock-in mice that produce lamin B1 from the Lmnb2 locus and knock-in mice that produce lamin B2 from the Lmnb1 locus). Both lines of knock-in mice manifested neurodevelopmental abnormalities similar to those in conventional knockout mice, indicating that lamins B1 and B2 have unique functions and that increased production of one B-type lamin cannot compensate for the loss of the other.
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Affiliation(s)
- John M Lee
- Department of Medicine; David Geffen School of Medicine; University of California; Los Angeles, CA USA
| | - Hea-Jin Jung
- Molecular Biology Institute; University of California; Los Angeles, CA USA
| | - Loren G Fong
- Department of Medicine; David Geffen School of Medicine; University of California; Los Angeles, CA USA
| | - Stephen G Young
- Department of Medicine; David Geffen School of Medicine; University of California; Los Angeles, CA USA
- Molecular Biology Institute; University of California; Los Angeles, CA USA
- Department of Human Genetics; David Geffen School of Medicine; University of California; Los Angeles, CA USA
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48
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Abstract
Much of the work on nuclear lamins during the past 15 years has focused on mutations in LMNA (the gene for prelamin A and lamin C) that cause particular muscular dystrophy, cardiomyopathy, partial lipodystrophy, and progeroid syndromes. These disorders, often called "laminopathies," mainly affect mesenchymal tissues (e.g., striated muscle, bone, and fibrous tissue). Recently, however, a series of papers have identified important roles for nuclear lamins in the central nervous system. Studies of knockout mice uncovered a key role for B-type lamins (lamins B1 and B2) in neuronal migration in the developing brain. Also, duplications of LMNB1 (the gene for lamin B1) have been shown to cause autosome-dominant leukodystrophy. Finally, recent studies have uncovered a peculiar pattern of nuclear lamin expression in the brain. Lamin C transcripts are present at high levels in the brain, but prelamin A expression levels are very low-due to regulation of prelamin A transcripts by microRNA 9. This form of prelamin A regulation likely explains why "prelamin A diseases" such as Hutchinson-Gilford progeria syndrome spare the central nervous system. In this review, we summarize recent progress in elucidating links between nuclear lamins and neurobiology.
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49
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Abstract
For over two decades, B-type lamins were thought to have roles in fundamental processes including correct assembly of nuclear envelopes, DNA replication, transcription and cell survival. Recent studies have questioned these roles and have instead emphasised the role of these proteins in tissue building and tissue integrity, particularly in tissues devoid of A-type lamins. Other studies have suggested that the expression of B-type lamins in somatic cells influences the rate of entry into states of cellular senescence. In humans duplication of the LMNB1 gene (encoding lamin B1) causes an adult onset neurodegenerative disorder, termed autosomal dominant leukodystrophy, whilst very recently, LMNB1 has been implicated as a susceptibility gene in neural tube defects. This is consistent with studies in mice that reveal a critical role for B-type lamins in neuronal migration and brain development. In this review, I will consider how different model systems have contributed to our understanding of the functions of B-type lamins and which of those functions are critical for human health and disease.
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Affiliation(s)
- C J Hutchison
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom.
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50
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Lee JM, Tu Y, Tatar A, Wu D, Nobumori C, Jung HJ, Yoshinaga Y, Coffinier C, de Jong PJ, Fong LG, Young SG. Reciprocal knock-in mice to investigate the functional redundancy of lamin B1 and lamin B2. Mol Biol Cell 2014; 25:1666-75. [PMID: 24672053 PMCID: PMC4019497 DOI: 10.1091/mbc.e14-01-0683] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/14/2014] [Accepted: 03/14/2014] [Indexed: 11/17/2022] Open
Abstract
Lamins B1 and B2 (B-type lamins) have very similar sequences and are expressed ubiquitously. In addition, both Lmnb1- and Lmnb2-deficient mice die soon after birth with neuronal layering abnormalities in the cerebral cortex, a consequence of defective neuronal migration. The similarities in amino acid sequences, expression patterns, and knockout phenotypes raise the question of whether the two proteins have redundant functions. To investigate this topic, we generated "reciprocal knock-in mice"-mice that make lamin B2 from the Lmnb1 locus (Lmnb1(B2/B2)) and mice that make lamin B1 from the Lmnb2 locus (Lmnb2(B1/B1)). Lmnb1(B2/B2) mice produced increased amounts of lamin B2 but no lamin B1; they died soon after birth with neuronal layering abnormalities in the cerebral cortex. However, the defects in Lmnb1(B2/B2) mice were less severe than those in Lmnb1-knockout mice, indicating that increased amounts of lamin B2 partially ameliorate the abnormalities associated with lamin B1 deficiency. Similarly, increased amounts of lamin B1 in Lmnb2(B1/B1) mice did not prevent the neurodevelopmental defects elicited by lamin B2 deficiency. We conclude that lamins B1 and B2 have unique roles in the developing brain and that increased production of one B-type lamin does not fully complement loss of the other.
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Affiliation(s)
- John M Lee
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Angelica Tatar
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Daniel Wu
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Chika Nobumori
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Hea-Jin Jung
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
| | - Yuko Yoshinaga
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Catherine Coffinier
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90095Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095
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