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Freyter BM, Abd Al-razaq MA, Isermann A, Dietz A, Azimzadeh O, Hekking L, Gomolka M, Rübe CE. Nuclear Fragility in Radiation-Induced Senescence: Blebs and Tubes Visualized by 3D Electron Microscopy. Cells 2022; 11:cells11020273. [PMID: 35053389 PMCID: PMC8774169 DOI: 10.3390/cells11020273] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/19/2021] [Accepted: 01/12/2022] [Indexed: 12/10/2022] Open
Abstract
Irreparable DNA damage following ionizing radiation (IR) triggers prolonged DNA damage response and induces premature senescence. Cellular senescence is a permanent state of cell-cycle arrest characterized by chromatin restructuring, altered nuclear morphology and acquisition of secretory phenotype, which contributes to senescence-related inflammation. However, the mechanistic connections for radiation-induced DNA damage that trigger these senescence-associated hallmarks are poorly understood. In our in vitro model of radiation-induced senescence, mass spectrometry-based proteomics was combined with high-resolution imaging techniques to investigate the interrelations between altered chromatin compaction, nuclear envelope destabilization and nucleo-cytoplasmic chromatin blebbing. Our findings confirm the general pathophysiology of the senescence-response, with disruption of nuclear lamin organization leading to extensive chromatin restructuring and destabilization of the nuclear membrane with release of chromatin fragments into the cytosol, thereby activating cGAS-STING-dependent interferon signaling. By serial block-face scanning electron microscopy (SBF-SEM) whole-cell datasets were acquired to investigate the morphological organization of senescent fibroblasts. High-resolution 3-dimensional (3D) reconstruction of the complex nuclear shape allows us to precisely visualize the segregation of nuclear blebs from the main nucleus and their fusion with lysosomes. By multi-view 3D electron microscopy, we identified nanotubular channels formed in lamin-perturbed nuclei of senescent fibroblasts; the potential role of these nucleo-cytoplasmic nanotubes for expulsion of damaged chromatin has to be examined.
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Affiliation(s)
- Benjamin M. Freyter
- Department of Radiation Oncology, Saarland University Medical Center, Kirrbergerstrasse Building 6.5, 66421 Homburg, Germany; (B.M.F.); (M.A.A.A.-r.); (A.I.)
| | - Mutaz A. Abd Al-razaq
- Department of Radiation Oncology, Saarland University Medical Center, Kirrbergerstrasse Building 6.5, 66421 Homburg, Germany; (B.M.F.); (M.A.A.A.-r.); (A.I.)
| | - Anna Isermann
- Department of Radiation Oncology, Saarland University Medical Center, Kirrbergerstrasse Building 6.5, 66421 Homburg, Germany; (B.M.F.); (M.A.A.A.-r.); (A.I.)
| | - Anne Dietz
- Department of Effects and Risks of Ionising & Non-Ionising Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany; (A.D.); (O.A.); (M.G.)
| | - Omid Azimzadeh
- Department of Effects and Risks of Ionising & Non-Ionising Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany; (A.D.); (O.A.); (M.G.)
| | | | - Maria Gomolka
- Department of Effects and Risks of Ionising & Non-Ionising Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany; (A.D.); (O.A.); (M.G.)
| | - Claudia E. Rübe
- Department of Radiation Oncology, Saarland University Medical Center, Kirrbergerstrasse Building 6.5, 66421 Homburg, Germany; (B.M.F.); (M.A.A.A.-r.); (A.I.)
- Correspondence: ; Tel.: +49-6841-1634614; Fax: +49-6841-1624699
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Kim YS, Fan R, Kremer L, Kuempel-Rink N, Mildner K, Zeuschner D, Hekking L, Stehling M, Bedzhov I. Deciphering epiblast lumenogenesis reveals proamniotic cavity control of embryo growth and patterning. Sci Adv 2021; 7:7/11/eabe1640. [PMID: 33692105 PMCID: PMC7946377 DOI: 10.1126/sciadv.abe1640] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
During the peri-implantation stages, the mouse embryo radically changes its appearance, transforming from a hollow-shaped blastocyst to an egg cylinder. At the same time, the epiblast gets reorganized from a simple ball of cells to a cup-shaped epithelial monolayer enclosing the proamniotic cavity. However, the cavity's function and mechanism of formation have so far been obscure. Through investigating the cavity formation, we found that in the epiblast, the process of lumenogenesis is driven by reorganization of intercellular adhesion, vectoral fluid transport, and mitotic paracellular water influx from the blastocoel into the emerging proamniotic cavity. By experimentally blocking lumenogenesis, we found that the proamniotic cavity functions as a hub for communication between the early lineages, enabling proper growth and patterning of the postimplantation embryo.
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Affiliation(s)
- Yung Su Kim
- Embryonic Self-Organization Research Group, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Rui Fan
- Embryonic Self-Organization Research Group, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Ludmila Kremer
- Transgenic Facility, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Nannette Kuempel-Rink
- Transgenic Facility, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Karina Mildner
- Electron Microscopy Facility, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Dagmar Zeuschner
- Electron Microscopy Facility, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Liesbeth Hekking
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Martin Stehling
- Flow Cytometry Unit, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany
| | - Ivan Bedzhov
- Embryonic Self-Organization Research Group, Max Planck Institute for Molecular Biomedicine, Röntgenstraße 20, 48149 Münster, Germany.
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