1
|
Zhu C, Yuan T, Krishnan J. Targeting cardiomyocyte cell cycle regulation in heart failure. Basic Res Cardiol 2024; 119:349-369. [PMID: 38683371 PMCID: PMC11142990 DOI: 10.1007/s00395-024-01049-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 03/11/2024] [Accepted: 03/29/2024] [Indexed: 05/01/2024]
Abstract
Heart failure continues to be a significant global health concern, causing substantial morbidity and mortality. The limited ability of the adult heart to regenerate has posed challenges in finding effective treatments for cardiac pathologies. While various medications and surgical interventions have been used to improve cardiac function, they are not able to address the extensive loss of functioning cardiomyocytes that occurs during cardiac injury. As a result, there is growing interest in understanding how the cell cycle is regulated and exploring the potential for stimulating cardiomyocyte proliferation as a means of promoting heart regeneration. This review aims to provide an overview of current knowledge on cell cycle regulation and mechanisms underlying cardiomyocyte proliferation in cases of heart failure, while also highlighting established and novel therapeutic strategies targeting this area for treatment purposes.
Collapse
Affiliation(s)
- Chaonan Zhu
- Department of Medicine III, Cardiology/Angiology/Nephrology, Goethe University Hospital, 60590, Frankfurt am Main, Germany
- Institute for Cardiovascular Regeneration, Goethe University, 60590, Frankfurt am Main, Germany
| | - Ting Yuan
- Department of Medicine III, Cardiology/Angiology/Nephrology, Goethe University Hospital, 60590, Frankfurt am Main, Germany.
- Institute for Cardiovascular Regeneration, Goethe University, 60590, Frankfurt am Main, Germany.
- German Center for Cardiovascular Research, Partner Site Rhein-Main, 60590, Frankfurt am Main, Germany.
- Cardio-Pulmonary Institute, Goethe University Hospital, 60590, Frankfurt am Main, Germany.
| | - Jaya Krishnan
- Department of Medicine III, Cardiology/Angiology/Nephrology, Goethe University Hospital, 60590, Frankfurt am Main, Germany.
- Institute for Cardiovascular Regeneration, Goethe University, 60590, Frankfurt am Main, Germany.
- German Center for Cardiovascular Research, Partner Site Rhein-Main, 60590, Frankfurt am Main, Germany.
- Cardio-Pulmonary Institute, Goethe University Hospital, 60590, Frankfurt am Main, Germany.
| |
Collapse
|
2
|
Palmer N, Talib SZA, Kaldis P. Diverse roles for CDK-associated activity during spermatogenesis. FEBS Lett 2019; 593:2925-2949. [PMID: 31566717 PMCID: PMC6900092 DOI: 10.1002/1873-3468.13627] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/20/2019] [Accepted: 09/26/2019] [Indexed: 12/22/2022]
Abstract
The primary function of cyclin-dependent kinases (CDKs) in complex with their activating cyclin partners is to promote mitotic division in somatic cells. This canonical cell cycle-associated activity is also crucial for fertility as it allows the proliferation and differentiation of stem cells within the reproductive organs to generate meiotically competent cells. Intriguingly, several CDKs exhibit meiosis-specific functions and are essential for the completion of the two reductional meiotic divisions required to generate haploid gametes. These meiosis-specific functions are mediated by both known CDK/cyclin complexes and meiosis-specific CDK-regulators and are important for a variety of processes during meiotic prophase. The majority of meiotic defects observed upon deletion of these proteins occur during the extended prophase I of the first meiotic division. Importantly a lack of redundancy is seen within the meiotic arrest phenotypes described for many of these proteins, suggesting intricate layers of cell cycle control are required for normal meiotic progression. Using the process of male germ cell development (spermatogenesis) as a reference, this review seeks to highlight the diverse roles of selected CDKs their activators, and their regulators during gametogenesis.
Collapse
Affiliation(s)
- Nathan Palmer
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.,Department of Biochemistry, National University of Singapore (NUS), Singapore, Singapore
| | - S Zakiah A Talib
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
| | - Philipp Kaldis
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.,Department of Biochemistry, National University of Singapore (NUS), Singapore, Singapore.,Department of Clinical Sciences, Clinical Research Centre (CRC), Lund University, Malmö, Sweden
| |
Collapse
|
3
|
Soh YQS, Mikedis MM, Kojima M, Godfrey AK, de Rooij DG, Page DC. Meioc maintains an extended meiotic prophase I in mice. PLoS Genet 2017; 13:e1006704. [PMID: 28380054 PMCID: PMC5397071 DOI: 10.1371/journal.pgen.1006704] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/19/2017] [Accepted: 03/20/2017] [Indexed: 01/13/2023] Open
Abstract
The meiosis-specific chromosomal events of homolog pairing, synapsis, and recombination occur over an extended meiotic prophase I that is many times longer than prophase of mitosis. Here we show that, in mice, maintenance of an extended meiotic prophase I requires the gene Meioc, a germ-cell specific factor conserved in most metazoans. In mice, Meioc is expressed in male and female germ cells upon initiation of and throughout meiotic prophase I. Mouse germ cells lacking Meioc initiate meiosis: they undergo pre-meiotic DNA replication, they express proteins involved in synapsis and recombination, and a subset of cells progress as far as the zygotene stage of prophase I. However, cells in early meiotic prophase—as early as the preleptotene stage—proceed to condense their chromosomes and assemble a spindle, as if having progressed to metaphase. Meioc-deficient spermatocytes that have initiated synapsis mis-express CYCLIN A2, which is normally expressed in mitotic spermatogonia, suggesting a failure to properly transition to a meiotic cell cycle program. MEIOC interacts with YTHDC2, and the two proteins pull-down an overlapping set of mitosis-associated transcripts. We conclude that when the meiotic chromosomal program is initiated, Meioc is simultaneously induced so as to extend meiotic prophase. Specifically, MEIOC, together with YTHDC2, promotes a meiotic (as opposed to mitotic) cell cycle program via post-transcriptional control of their target transcripts. Meiosis is the specialized cell division that halves the genetic content of germ cells to produce haploid gametes. This reductive division is preceded by a preparative phase of the cell cycle, meiotic prophase I, during which several meiosis-specific chromosomal events occur. Across sexually reproducing organisms, prophase of meiosis I is dramatically longer than mitotic prophase. However, it was not known in mammals how and why meiotic prophase I is extended. We have identified a mouse mutant in which this extended prophase I is disrupted: germ cells lacking Meioc initiate meiosis, but prematurely proceed to metaphase. Mutant male meiotic germ cells mis-express a cell cycle regulator that is normally expressed in mitotic male germ cells, suggesting that Meioc is required for germ cells to properly transition to a meiotic cell cycle program. Biochemical analyses of proteins and transcripts that associate with MEIOC protein suggest that MEIOC may promote the transition from a mitotic to meiotic cell cycle program by post-transcriptionally regulating target transcripts. Our studies indicate that in mammals, as in other sexually reproducing organisms, meiotic prophase I must be extended to allow time for meiotic chromosomal events to reach completion.
Collapse
Affiliation(s)
- Y. Q. Shirleen Soh
- Whitehead Institute, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | | | - Mina Kojima
- Whitehead Institute, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | - Alexander K. Godfrey
- Whitehead Institute, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | | | - David C. Page
- Whitehead Institute, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- Howard Hughes Medical Institute, Whitehead Institute, Cambridge, MA, United States of America
- * E-mail:
| |
Collapse
|
4
|
Goloborodko A, Imakaev MV, Marko JF, Mirny L. Compaction and segregation of sister chromatids via active loop extrusion. eLife 2016; 5:e14864. [PMID: 27192037 PMCID: PMC4914367 DOI: 10.7554/elife.14864] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 05/18/2016] [Indexed: 12/17/2022] Open
Abstract
The mechanism by which chromatids and chromosomes are segregated during mitosis and meiosis is a major puzzle of biology and biophysics. Using polymer simulations of chromosome dynamics, we show that a single mechanism of loop extrusion by condensins can robustly compact, segregate and disentangle chromosomes, arriving at individualized chromatids with morphology observed in vivo. Our model resolves the paradox of topological simplification concomitant with chromosome 'condensation', and explains how enzymes a few nanometers in size are able to control chromosome geometry and topology at micron length scales. We suggest that loop extrusion is a universal mechanism of genome folding that mediates functional interactions during interphase and compacts chromosomes during mitosis.
Collapse
Affiliation(s)
- Anton Goloborodko
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Maxim V Imakaev
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
- Department of Physics and Astronomy, Northwestern University, Evanston, United States
| | - Leonid Mirny
- Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, United States
| |
Collapse
|
5
|
Effects of Creatine and Its Analog, β-Guanidinopropionic Acid, on the Differentiation of and Nucleoli in Myoblasts. Biosci Biotechnol Biochem 2014; 75:1085-9. [PMID: 21670531 DOI: 10.1271/bbb.100901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
6
|
McRae R, Lai B, Fahrni CJ. Subcellular redistribution and mitotic inheritance of transition metals in proliferating mouse fibroblast cells. Metallomics 2013; 5:52-61. [PMID: 23212029 PMCID: PMC3769613 DOI: 10.1039/c2mt20176c] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synchrotron X-ray fluorescence microscopy of non-synchronized NIH 3T3 fibroblasts revealed an intriguing redistribution dynamics that defines the inheritance of trace metals during mitosis. At metaphase, the highest density areas of Zn and Cu are localized in two distinct regions adjacent to the metaphase plate. As the sister chromatids are pulled towards the spindle poles during anaphase, Zn and Cu gradually move to the center and partition into the daughter cells to yield a pair of twin pools during cytokinesis. Colocalization analyses demonstrated high spatial correlations between Zn, Cu, and S throughout all mitotic stages, while Fe showed consistently different topographies characterized by high-density spots distributed across the entire cell. Whereas the total amount of Cu remained similar compared to interphase cells, mitotic Zn levels increased almost 3-fold, suggesting a prominent physiological role that lies beyond the requirement of Zn as a cofactor in metalloproteins or messenger in signaling pathways.
Collapse
Affiliation(s)
- Reagan McRae
- School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA 30332, U.S.A
| | - Barry Lai
- Advanced Photon Source, X-ray Science Division, Argonne National Laboratory, Argonne, IL 60439, U.S.A
| | - Christoph J. Fahrni
- School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA 30332, U.S.A
| |
Collapse
|
7
|
Ogawa T, Sei H, Konishi H, Shishioh-Ikejima N, Kiyama H. The absence of somatotroph proliferation during continuous stress is a result of the lack of extracellular signal-regulated kinase 1/2 activation. J Neuroendocrinol 2012; 24:1335-45. [PMID: 22612533 DOI: 10.1111/j.1365-2826.2012.02338.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The integrity of homeostasis can be affected by chronic stress, and hyposomatotropism is evident in chronic stress-associated illnesses. In the present study, we demonstrated that a continuous stress (CS) severely affected somatotrophs among hormone-secreting cells in the anterior lobe (AL) of the pituitary by using a rat CS model. Among AL cells, the proliferation of somatotrophs was almost entirely suppressed in rats that had 3-5 days of CS (5dCS), although other hormone-secreting cells continued to proliferate. The cell size of somatotrophs was reduced at 5dCS (P<0.01), the number of secretory granules was increased at 3dCS (P<0.01) and serum growth hormone (GH) was on declining trend during 1 to 5dCS, suggesting that GH release was inhibited. GH-releasing hormone (GHRH) mRNA level in the arcuate nucleus was transiently decreased, whereas its receptor expression in the AL was significantly increased in CS rats. When 5dCS rats were injected with GHRH, transient GH secretion was observed, whereas proliferation of somatotrophs did not occur. The GHRH administration failed to stimulate extracellular signal-regulated kinase (ERK) 1/2 phosphorylation and the nuclear translocation of ERK in somatotrophs. These results suggest that somatotrophs of 5dCS rats expressed sufficient GHRH receptor, which could transfer a signal for GH release. However, the GHRH-induced proliferation signal was blocked somewhere between the receptor and ERK1/2. Because significant increase of corticosterone in the initial stage (the 1-3dCS) was observed in this model, the corticosterone may affect the signalling. Although the mechanism underlying the blockage of the proliferation signal in somatotrophs under CS remains unclear, these somatotrophic disorder, suggesting that the present animal model may be useful for understanding the molecular mechanisms of chronic stress-associated illnesses.
Collapse
Affiliation(s)
- T Ogawa
- Department of Anatomy & Neurobiology, Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka, Japan
| | | | | | | | | |
Collapse
|
8
|
Abstract
Here we use a concept of cell state, which can be defined as the conjunction of expression levels of an arbitrary number of biomolecules or modifications thereof that oscillate, to classify mitotic cells. We describe detection of cell states with quantitative immunofluorescence measurements performed by laser scanning cytometry. This platform allows both measurement of the cell states, capture of cell images within those states, and subsequent analysis of each image to classify by traditional mitotic stages based on nuclear morphology.
Collapse
Affiliation(s)
- Tammy Stefan
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA
| | | |
Collapse
|
9
|
Wang Z, Xie Y, Zhang L, Zhang H, An X, Wang T, Meng A. Migratory Localization of Cyclin D2-Cdk4 Complex Suggests a Spatial Regulation of the G1-S Transition. Cell Struct Funct 2008; 33:171-83. [DOI: 10.1247/csf.08019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Zizhang Wang
- Research Center for Molecular and Developmental Biology, Institute of Botany, Chinese Academy of Sciences
- Department of Biological Sciences and Biotechnology, Tsinghua University
| | - Yongli Xie
- Department of Biological Sciences and Biotechnology, Tsinghua University
| | - Lixia Zhang
- Department of Biological Sciences and Biotechnology, Tsinghua University
| | - Haiwen Zhang
- Department of Biological Sciences and Biotechnology, Tsinghua University
| | - Xiaojing An
- Research Center for Molecular and Developmental Biology, Institute of Botany, Chinese Academy of Sciences
| | - Tai Wang
- Research Center for Molecular and Developmental Biology, Institute of Botany, Chinese Academy of Sciences
| | - Anming Meng
- Department of Biological Sciences and Biotechnology, Tsinghua University
| |
Collapse
|
10
|
Trencsenyi G, Ujvarosi K, Nagy G, Banfalvi G. Transition from Chromatin Bodies to Linear Chromosomes in Nuclei of Murine PreB Cells Synchronized in S Phase. DNA Cell Biol 2007; 26:549-56. [PMID: 17688406 DOI: 10.1089/dna.2007.0603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chromatin structures and individual interphase chromosomes escaping nuclei of reversibly permeabilized cells were analyzed in a cell cycle-dependent manner. Cells were synchronized by counterflow centrifugal elutriation. Individual interphase chromosomes became visible as distinct fibrous chromatin bodies from mid-S-phase, turning to elongated chromosomes by the end of S phase. Major interphase chromosomal forms include (1) mid-S-phase chromatin bodies at 3.0 C-value, (2) elongated chromatin bodies later in mid-S-phase (3.25 C-value), (3) chromatin bodies with head and leg portions later in S phase (3.5 C-value), (4) supercoiled ribbons later in S phase seen as twisted prechromosomes (3.7 C-value), and (5) end-S-phase elongated, bent prechromosomal structures (3.9 C-value). The first karyotype analysis of the earliest forms of chromosomes referred to as chromatin bodies was performed.
Collapse
Affiliation(s)
- Gyorgy Trencsenyi
- Department of Microbial Biotechnology and Cell Biology, University of Debrecen, Debrecen, Hungary
| | | | | | | |
Collapse
|
11
|
Escargueil A, Larsen A. Mitosis-specific MPM-2 phosphorylation of DNA topoisomerase IIalpha is regulated directly by protein phosphatase 2A. Biochem J 2007; 403:235-42. [PMID: 17212588 PMCID: PMC1874246 DOI: 10.1042/bj20061460] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent results suggest a role for topoIIalpha (topoisomerase IIalpha) in the fine-tuning of mitotic entry. Mitotic entry is accompanied by the formation of specific phosphoepitopes such as MPM-2 (mitotic protein monoclonal 2) that are believed to control mitotic processes. Surprisingly, the MPM-2 kinase of topoIIalpha was identified as protein kinase CK2, otherwise known as a constitutive interphase kinase. This suggested the existence of alternative pathways for the creation of mitotic phosphoepitopes, different from the classical pathway where the substrate is phosphorylated by a mitotic kinase. In the present paper, we report that topoIIalpha is co-localized with both CK2 and PP2A (protein phosphatase 2A) during interphase. Simultaneous incubation of purified topoIIalpha with CK2 and PP2A had minimal influence on the total phosphorylation levels of topoIIalpha, but resulted in complete disappearance of the MPM-2 phosphoepitope owing to opposite sequence preferences of CK2 and PP2A. Accordingly, short-term exposure of interphase cells to okadaic acid, a selective PP2A inhibitor, was accompanied by the specific appearance of the MPM-2 phosphoepitope on topoIIalpha. During early mitosis, PP2A was translocated from the nucleus, while CK2 remained in the nucleus until pro-metaphase thus permitting the formation of the MPM-2 phosphoepitope. These results underline the importance of protein phosphatases as an alternative way of creating cell-cycle-specific phosphoepitopes.
Collapse
Affiliation(s)
- Alexandre E. Escargueil
- Group of Cancer Biology and Therapeutics, Inserm U673, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, 75572 Paris Cedex 12, France, and Université Pierre et Marie Curie, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, 75572 Paris Cedex 12, France
| | - Annette K. Larsen
- Group of Cancer Biology and Therapeutics, Inserm U673, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, 75572 Paris Cedex 12, France, and Université Pierre et Marie Curie, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, 75572 Paris Cedex 12, France
- To whom correspondence should be addressed (email )
| |
Collapse
|
12
|
Skladanowski A, Côme MG, Sabisz M, Escargueil AE, Larsen AK. Down-Regulation of DNA Topoisomerase IIα Leads to Prolonged Cell Cycle Transit in G2and Early M Phases and Increased Survival to Microtubule-Interacting Agents. Mol Pharmacol 2005; 68:625-34. [PMID: 15942022 DOI: 10.1124/mol.105.013995] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Microtubule binders are cell cycle-specific agents with preferential cytotoxicity toward mitotic cells. We have characterized vincristine-selected human leukemia cells to establish whether development of vincristine resistance was accompanied by changes in cell cycle kinetics and distribution. Our results indicate that vincristine resistance is accompanied by delayed G2 transit and prolonged early mitosis in both the absence and the presence of the microtubule binder nocodazole. The altered G2/M regulation is accompanied by resistance to short-term (12 h) but not continuous nocodazole exposure in agreement with the transient nature of the observed cell cycle alterations. Western blot analysis indicates that vincristine-selection is accompanied by down-regulation of topoisomerase IIalpha without detectable alterations of the other mitotic regulators studied, including Cdk1, p21, 14-3-3sigma, and 14-3-3epsilon. This was associated with at least 7-fold less chromosome-associated topoisomerase IIalpha, decreased catalytic activity, and cross-resistance to topoisomerase II inhibitors. Characterization of isogenic cell lines expressing different levels of topoisomerase II proteins shows that cellular levels of topoisomerase IIalpha, but not the closely related topoisomerase IIbeta, directly influence the cell cycle kinetics in G2 and early mitosis as well as the resistance to nocodazole. These results underline the importance of topoisomerase IIalpha in late G2 and early M phases and provide evidence for an as-yet-unsuspected interaction between topoisomerase II and microtubule-directed agents.
Collapse
Affiliation(s)
- Andrzej Skladanowski
- Group of Molecular and Clinical Cancer Therapeutics, INSERM U673, Hôpital Saint-Antoine, 75571 Paris 12, France
| | | | | | | | | |
Collapse
|
13
|
Bieberich E, MacKinnon S, Silva J, Noggle S, Condie BG. Regulation of cell death in mitotic neural progenitor cells by asymmetric distribution of prostate apoptosis response 4 (PAR-4) and simultaneous elevation of endogenous ceramide. J Cell Biol 2003; 162:469-79. [PMID: 12885759 PMCID: PMC2172704 DOI: 10.1083/jcb.200212067] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cell death and survival of neural progenitor (NP) cells are determined by signals that are largely unknown. We have analyzed pro-apoptotic signaling in individual NP cells that have been derived from mouse embryonic stem cells. NP formation was concomitant with elevated apoptosis and increased expression of ceramide and prostate apoptosis response 4 (PAR-4). Morpholino oligonucleotide-mediated antisense knockdown of PAR-4 or inhibition of ceramide biosynthesis reduced stem cell apoptosis, whereas PAR-4 overexpression and treatment with ceramide analogs elevated apoptosis. Apoptotic cells also stained for proliferating cell nuclear antigen (a nuclear mitosis marker protein), but not for nestin (a marker for NP cells). In mitotic cells, asymmetric distribution of PAR-4 and nestin resulted in one nestin(-)/PAR-4(+) daughter cell, in which ceramide elevation induced apoptosis. The other cell was nestin(+), but PAR-4(-), and was not apoptotic. Asymmetric distribution of PAR-4 and simultaneous elevation of endogenous ceramide provides a possible mechanism underlying asymmetric differentiation and apoptosis of neuronal stem cells in the developing brain.
Collapse
Affiliation(s)
- Erhard Bieberich
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, 1120 15th Street, Room CB-2803, Augusta, GA 30912, USA.
| | | | | | | | | |
Collapse
|
14
|
|
15
|
Jaunin F, Visser AE, Cmarko D, Aten JA, Fakan S. Fine structural in situ analysis of nascent DNA movement following DNA replication. Exp Cell Res 2000; 260:313-23. [PMID: 11035926 DOI: 10.1006/excr.2000.4999] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nascent DNA (newly replicated DNA) was visualized in situ with regard to the position of the previously replicated DNA and to chromatin structure. Localization of nascent DNA at the replication sites can be achieved through pulse labeling of cells with labeled DNA precursors during very short periods of time. We were able to label V79 Chinese Hamster cells for as shortly as 2 min with BrdU; Br-DNA, detected by immunoelectron microscopy, occurs at the periphery of dense chromatin, at individual dispersed chromatin fibers, and within dispersed chromatin areas. In these regions DNA polymerase alpha was also visualized. After a 5-min BrdU pulse, condensed chromatin also became labeled. When the pulse was followed by a chase, a larger number of gold particles occurred on condensed chromatin. Double-labeling experiments, consisting in first incubating cells with IdU for 20 min, chased for 10 min and then labeled for 5 min with CldU, reveal CldU-labeled nascent DNA on the periphery of condensed chromatin, while previously replicated IdU-labeled DNA has been internalized into condensed chromatin. Altogether, these results show that the sites of DNA replication correspond essentially to perichromatin regions and that the newly replicated DNA moves rapidly from replication sites toward the interior of condensed chromatin areas.
Collapse
Affiliation(s)
- F Jaunin
- Centre of Electron Microscopy, University of Lausanne, 27 Bugnon, Lausanne, CH-1005, Switzerland
| | | | | | | | | |
Collapse
|