1
|
Zhang Z, Yang H, Fang L, Zhao G, Xiang J, Zheng JC, Qin Z. DOS-3 mediates cell-non-autonomous DAF-16/FOXO activity in antagonizing age-related loss of C. elegans germline stem/progenitor cells. Nat Commun 2024; 15:4904. [PMID: 38851828 PMCID: PMC11162419 DOI: 10.1038/s41467-024-49318-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 05/29/2024] [Indexed: 06/10/2024] Open
Abstract
Age-related depletion of stem cells causes tissue degeneration and failure to tissue regeneration, driving aging at the organismal level. Previously we reported a cell-non-autonomous DAF-16/FOXO activity in antagonizing the age-related loss of germline stem/progenitor cells (GSPCs) in C. elegans, indicating that regulation of stem cell aging occurs at the organ system level. Here we discover the molecular effector that links the cell-non-autonomous DAF-16/FOXO activity to GSPC maintenance over time by performing a tissue-specific DAF-16/FOXO transcriptome analysis. Our data show that dos-3, which encodes a non-canonical Notch ligand, is a direct transcriptional target of DAF-16/FOXO and mediates the effect of the cell-non-autonomous DAF-16/FOXO activity on GSPC maintenance through activating Notch signaling in the germ line. Importantly, expression of a human homologous protein can functionally substitute for DOS-3 in this scenario. As Notch signaling controls the specification of many tissue stem cells, similar mechanisms may exist in other aging stem cell systems.
Collapse
Affiliation(s)
- Zhifei Zhang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China
| | - Haiyan Yang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China
| | - Lei Fang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China
| | - Guangrong Zhao
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China
| | - Jun Xiang
- Department of Urology, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China.
| | - Jialin C Zheng
- Center for Translational Neurodegeneration and Regenerative Therapy, Tongji Hospital Affiliated to Tongji University, Shanghai, 200065, China.
- State Key Laboratory of Cardiology and Medical Innovation Center, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China.
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, 200080, China.
- Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital affiliated to Tongji University School of Medicine, Shanghai, 200080, China.
- Innovation Center of Medical Basic Research for Brain Aging and Associated Diseases, Ministry of Education, Tongji University, Shanghai, 200331, China.
- Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, 200331, China.
- Shanghai Frontiers Science Center of Nanocatalytic Medicine, Tongji University School of Medicine, Shanghai, 200331, China.
| | - Zhao Qin
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopedic Department of Tongji Hospital, School of Medicine, Tongji University, Shanghai, 200065, China.
- Innovation Center of Medical Basic Research for Brain Aging and Associated Diseases, Ministry of Education, Tongji University, Shanghai, 200331, China.
- Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, 200331, China.
| |
Collapse
|
2
|
Valet M, Narbonne P. Formation of benign tumors by stem cell deregulation. PLoS Genet 2022; 18:e1010434. [PMID: 36301803 PMCID: PMC9612571 DOI: 10.1371/journal.pgen.1010434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Within living organisms, stem cells respond to various cues, including to niche signals and growth factors. Niche signals originate from the stem cell's microenvironment and promote the undifferentiated state by preventing differentiation, allowing for stem cell self-renewal. On the other hand, growth factors promote stem cell growth and proliferation, while their sources comprise of a systemic input reflecting the animal's nutritional and metabolic status, and a localized, homeostatic feedback signal from the tissue that the stem cells serve. That homeostatic signal prevents unnecessary stem cell proliferation when the corresponding differentiated tissues already have optimal cell contents. Here, we recapitulate progresses made in our understanding of in vivo stem cell regulation, largely using simple models, and draw the conclusion that 2 types of stem cell deregulations can provoke the formation of benign tumors. Namely, constitutive niche signaling promotes the formation of undifferentiated "stem cell" tumors, while defective homeostatic signaling leads to the formation of differentiated tumors. Finally, we provide evidence that these general principles may be conserved in mammals and as such, may underlie benign tumor formation in humans, while benign tumors can evolve into cancer.
Collapse
Affiliation(s)
- Matthieu Valet
- Département de biologie médicale, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
| | - Patrick Narbonne
- Département de biologie médicale, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
- * E-mail:
| |
Collapse
|
3
|
Scharf A, Pohl F, Egan BM, Kocsisova Z, Kornfeld K. Reproductive Aging in Caenorhabditis elegans: From Molecules to Ecology. Front Cell Dev Biol 2021; 9:718522. [PMID: 34604218 PMCID: PMC8481778 DOI: 10.3389/fcell.2021.718522] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/04/2021] [Indexed: 11/13/2022] Open
Abstract
Aging animals display a broad range of progressive degenerative changes, and one of the most fascinating is the decline of female reproductive function. In the model organism Caenorhabditis elegans, hermaphrodites reach a peak of progeny production on day 2 of adulthood and then display a rapid decline; progeny production typically ends by day 8 of adulthood. Since animals typically survive until day 15 of adulthood, there is a substantial post reproductive lifespan. Here we review the molecular and cellular changes that occur during reproductive aging, including reductions in stem cell number and activity, slowing meiotic progression, diminished Notch signaling, and deterioration of germ line and oocyte morphology. Several interventions have been identified that delay reproductive aging, including mutations, drugs and environmental factors such as temperature. The detailed description of reproductive aging coupled with interventions that delay this process have made C. elegans a leading model system to understand the mechanisms that drive reproductive aging. While reproductive aging has dramatic consequences for individual fertility, it also has consequences for the ecology of the population. Population dynamics are driven by birth and death, and reproductive aging is one important factor that influences birth rate. A variety of theories have been advanced to explain why reproductive aging occurs and how it has been sculpted during evolution. Here we summarize these theories and discuss the utility of C. elegans for testing mechanistic and evolutionary models of reproductive aging.
Collapse
Affiliation(s)
- Andrea Scharf
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| | - Franziska Pohl
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States.,Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Brian M Egan
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| | - Zuzana Kocsisova
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, United States
| |
Collapse
|
4
|
Tolkin T, Hubbard EJA. Germline Stem and Progenitor Cell Aging in C. elegans. Front Cell Dev Biol 2021; 9:699671. [PMID: 34307379 PMCID: PMC8297657 DOI: 10.3389/fcell.2021.699671] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
Like many animals and humans, reproduction in the nematode C. elegans declines with age. This decline is the cumulative result of age-related changes in several steps of germline function, many of which are highly accessible for experimental investigation in this short-lived model organism. Here we review recent work showing that a very early and major contributing step to reproductive decline is the depletion of the germline stem and progenitor cell pool. Since many cellular and molecular aspects of stem cell biology and aging are conserved across animals, understanding mechanisms of age-related decline of germline stem and progenitor cells in C. elegans has broad implications for aging stem cells, germline stem cells, and reproductive aging.
Collapse
Affiliation(s)
- Theadora Tolkin
- Department of Cell Biology, Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York, NY, United States
| | - E Jane Albert Hubbard
- Department of Cell Biology, Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York, NY, United States
| |
Collapse
|
5
|
Knapp-Wilson A, Pereira GC, Buzzard E, Ford HC, Richardson A, Corey RA, Neal C, Verkade P, Halestrap AP, Gold VAM, Kuwabara PE, Collinson I. Maintenance of complex I and its supercomplexes by NDUF-11 is essential for mitochondrial structure, function and health. J Cell Sci 2021; 134:jcs258399. [PMID: 34106255 PMCID: PMC8277142 DOI: 10.1242/jcs.258399] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial supercomplexes form around a conserved core of monomeric complex I and dimeric complex III; wherein a subunit of the former, NDUFA11, is conspicuously situated at the interface. We identified nduf-11 (B0491.5) as encoding the Caenorhabditis elegans homologue of NDUFA11. Animals homozygous for a CRISPR-Cas9-generated knockout allele of nduf-11 arrested at the second larval (L2) development stage. Reducing (but not eliminating) expression using RNAi allowed development to adulthood, enabling characterisation of the consequences: destabilisation of complex I and its supercomplexes and perturbation of respiratory function. The loss of NADH dehydrogenase activity was compensated by enhanced complex II activity, with the potential for detrimental reactive oxygen species (ROS) production. Cryo-electron tomography highlighted aberrant morphology of cristae and widening of both cristae junctions and the intermembrane space. The requirement of NDUF-11 for balanced respiration, mitochondrial morphology and development presumably arises due to its involvement in complex I and supercomplex maintenance. This highlights the importance of respiratory complex integrity for health and the potential for its perturbation to cause mitochondrial disease. This article has an associated First Person interview with Amber Knapp-Wilson, joint first author of the paper.
Collapse
Affiliation(s)
| | | | - Emma Buzzard
- Living Systems Institute, Stocker Road, University of Exeter, Exeter EX4 4QD, UK
- College of Life and Environmental Sciences,Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Holly C. Ford
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | | | - Robin A. Corey
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Chris Neal
- Wolfson Bioimaging Facility, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | | | - Vicki A. M. Gold
- Living Systems Institute, Stocker Road, University of Exeter, Exeter EX4 4QD, UK
- College of Life and Environmental Sciences,Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | | | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| |
Collapse
|
6
|
Robinson-Thiewes S, Dufour B, Martel PO, Lechasseur X, Brou AAD, Roy V, Chen Y, Kimble J, Narbonne P. Non-autonomous regulation of germline stem cell proliferation by somatic MPK-1/MAPK activity in C. elegans. Cell Rep 2021; 35:109162. [PMID: 34038716 PMCID: PMC8182673 DOI: 10.1016/j.celrep.2021.109162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/17/2021] [Accepted: 04/30/2021] [Indexed: 11/03/2022] Open
Abstract
Extracellular-signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) is a major positive regulator of cell proliferation, which is often upregulated in cancer. However, few studies have addressed ERK/MAPK regulation of proliferation within a complete organism. The Caenorhabditis elegans ERK/MAPK ortholog MPK-1 is best known for its control of somatic organogenesis and germline differentiation, but it also stimulates germline stem cell proliferation. Here, we show that the germline-specific MPK-1B isoform promotes germline differentiation but has no apparent role in germline stem cell proliferation. By contrast, the soma-specific MPK-1A isoform promotes germline stem cell proliferation non-autonomously. Indeed, MPK-1A functions in the intestine or somatic gonad to promote germline proliferation independent of its other known roles. We propose that a non-autonomous role of ERK/MAPK in stem cell proliferation may be conserved across species and various tissue types, with major clinical implications for cancer and other diseases. The prevailing paradigm is that ERK/MAPK functions autonomously to promote cell proliferation upon mitogen stimulation. Robinson-Thiewes et al. now demonstrate that C. elegans ERK/MAPK acts within somatic tissues to non-autonomously promote the proliferation of germline stem cells. Germline ERK/MAPK is thus dispensable for germline stem cell proliferation.
Collapse
Affiliation(s)
| | - Benjamin Dufour
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Pier-Olivier Martel
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Xavier Lechasseur
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Amani Ange Danielle Brou
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Vincent Roy
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada; Département de Biologie Moléculaire, de Biochimie Médicale et de pathologie, Faculté de Médecine, Université Laval, QC G1R 3S3, Canada
| | - Yunqing Chen
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Judith Kimble
- Department of Genetics, University of Wisconsin-Madison, Madison, WI 53706-1580, USA
| | - Patrick Narbonne
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada; Département de Biologie Moléculaire, de Biochimie Médicale et de pathologie, Faculté de Médecine, Université Laval, QC G1R 3S3, Canada.
| |
Collapse
|
7
|
Molecular basis of reproductive senescence: insights from model organisms. J Assist Reprod Genet 2020; 38:17-32. [PMID: 33006069 DOI: 10.1007/s10815-020-01959-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 09/25/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Reproductive decline due to parental age has become a major barrier to fertility as couples have delayed having offspring into their thirties and forties. Advanced parental age is also associated with increased incidence of neurological and cardiovascular disease in offspring. Thus, elucidating the etiology of reproductive decline is of clinical importance. METHODS Deciphering the underlying processes that drive reproductive decline is particularly challenging in women in whom a discrete oocyte pool is established during embryogenesis and may remain dormant for tens of years. Instead, our understanding of the processes that drive reproductive senescence has emerged from studies in model organisms, both vertebrate and invertebrate, that are the focus of this literature review. CONCLUSIONS Studies of reproductive aging in model organisms not only have revealed the detrimental cellular changes that occur with age but also are helping identify major regulator proteins controlling them. Here, we discuss what we have learned from model organisms with respect to the molecular mechanisms that maintain both genome integrity and oocyte quality.
Collapse
|
8
|
Abstract
Sexual interactions negatively impact health and longevity in many species across the animal kingdom. C. elegans has been established as a good model to study how mating and intense sexual interactions influence longevity of the individuals. In this chapter, we review the most recent discoveries in this field. We first describe the phenotypes caused by intense mating, including shrinking, fat loss, and glycogen loss. We then describe three major mechanisms underlying mating-induced killing: germline activation, seminal fluid transfer, and male pheromone-mediated toxicity. Next, we summarize the current knowledge of genetic pathways involved in regulating mating-induced death, including DAF-9/DAF-12 steroid signaling, Insulin/IGF-1 signaling (IIS), and TOR signaling. Finally, we discuss the possible fitness benefits of mating-induced death. Throughout this review, we compare and contrast mating-induced death between the sexes and among different species in an effort to discuss this phenomenon and underlying mechanisms from the evolutionary perspective. Further investigation using mated C. elegans will improve our understanding of sexual antagonism, as well as the coordination between reproduction and somatic longevity in response to various external signals. Due to the evolutionary conservation in many aspects of mating-induced death, what we learn from a short-lived mated worm could provide new strategies to improve our own fitness and longevity.
Collapse
Affiliation(s)
- Cheng Shi
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Coleen T Murphy
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
| |
Collapse
|
9
|
Hubbard EJA, Schedl T. Biology of the Caenorhabditis elegans Germline Stem Cell System. Genetics 2019; 213:1145-1188. [PMID: 31796552 PMCID: PMC6893382 DOI: 10.1534/genetics.119.300238] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
Stem cell systems regulate tissue development and maintenance. The germline stem cell system is essential for animal reproduction, controlling both the timing and number of progeny through its influence on gamete production. In this review, we first draw general comparisons to stem cell systems in other organisms, and then present our current understanding of the germline stem cell system in Caenorhabditis elegans In contrast to stereotypic somatic development and cell number stasis of adult somatic cells in C. elegans, the germline stem cell system has a variable division pattern, and the system differs between larval development, early adult peak reproduction and age-related decline. We discuss the cell and developmental biology of the stem cell system and the Notch regulated genetic network that controls the key decision between the stem cell fate and meiotic development, as it occurs under optimal laboratory conditions in adult and larval stages. We then discuss alterations of the stem cell system in response to environmental perturbations and aging. A recurring distinction is between processes that control stem cell fate and those that control cell cycle regulation. C. elegans is a powerful model for understanding germline stem cells and stem cell biology.
Collapse
Affiliation(s)
- E Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine, Departments of Cell Biology and Pathology, New York University School of Medicine, New York 10016
| | - Tim Schedl
- and Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
| |
Collapse
|
10
|
Kocsisova Z, Kornfeld K, Schedl T. Rapid population-wide declines in stem cell number and activity during reproductive aging in C. elegans. Development 2019; 146:dev173195. [PMID: 30936182 PMCID: PMC6503983 DOI: 10.1242/dev.173195] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023]
Abstract
C. elegans hermaphrodites display dramatic age-related decline of reproduction early in life, while somatic functions are still robust. To understand reproductive aging, we analyzed the assembly line of oocyte production that generates fertilized eggs. Aging germlines displayed both sporadic and population-wide changes. A small fraction of aging animals displayed endomitotic oocytes in the germline and other defects. By contrast, all animals displayed age-related decreases in germline size and function. As early as day 3 of adulthood, animals displayed fewer stem cells and a slower cell cycle, which combine to substantially decrease progenitor zone output. The C. elegans germline is the only adult tissue that contains stem cells, allowing the analysis of stem cells in aging. To investigate the mechanism of the decrease in stem cell number, we analyzed the Notch signaling pathway. The Notch effectors LST-1 and SYGL-1 displayed age-related decreases in expression domains, suggesting a role for Notch signaling in germline aging. The results indicate that although sporadic defects account for the sterility of some animals, population-wide changes account for the overall pattern of reproductive aging.
Collapse
Affiliation(s)
- Zuzana Kocsisova
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
- Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Tim Schedl
- Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
| |
Collapse
|
11
|
Developmental Control of the Cell Cycle: Insights from Caenorhabditis elegans. Genetics 2019; 211:797-829. [PMID: 30846544 PMCID: PMC6404260 DOI: 10.1534/genetics.118.301643] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
During animal development, a single fertilized egg forms a complete organism with tens to trillions of cells that encompass a large variety of cell types. Cell cycle regulation is therefore at the center of development and needs to be carried out in close coordination with cell differentiation, migration, and death, as well as tissue formation, morphogenesis, and homeostasis. The timing and frequency of cell divisions are controlled by complex combinations of external and cell-intrinsic signals that vary throughout development. Insight into how such controls determine in vivo cell division patterns has come from studies in various genetic model systems. The nematode Caenorhabditis elegans has only about 1000 somatic cells and approximately twice as many germ cells in the adult hermaphrodite. Despite the relatively small number of cells, C. elegans has diverse tissues, including intestine, nerves, striated and smooth muscle, and skin. C. elegans is unique as a model organism for studies of the cell cycle because the somatic cell lineage is invariant. Somatic cells divide at set times during development to produce daughter cells that adopt reproducible developmental fates. Studies in C. elegans have allowed the identification of conserved cell cycle regulators and provided insights into how cell cycle regulation varies between tissues. In this review, we focus on the regulation of the cell cycle in the context of C. elegans development, with reference to other systems, with the goal of better understanding how cell cycle regulation is linked to animal development in general.
Collapse
|
12
|
Cherif-Feildel M, Heude Berthelin C, Adeline B, Rivière G, Favrel P, Kellner K. Molecular evolution and functional characterisation of insulin related peptides in molluscs: Contributions of Crassostrea gigas genomic and transcriptomic-wide screening. Gen Comp Endocrinol 2019; 271:15-29. [PMID: 30389328 DOI: 10.1016/j.ygcen.2018.10.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 12/18/2022]
Abstract
Insulin Related Peptides (IRPs) belong to the insulin superfamily and possess a typical structure with two chains, B and A, linked by disulphide bonds. As the sequence conservation is usually low between members, IRPs are classified according to the number and position of their disulphide bonds. In molluscan species, the first IRPs identified, named Molluscan Insulin-related Peptides (MIPs), exhibit four disulphide bonds. The genomic and transcriptomic data screening in the Pacific oyster Crassostrea gigas (Mollusc, Bivalvia) allowed us to identify six IRP sequences belonging to three structural groups. Cg-MIP1 to 4 have the typical structure of MIPs with four disulphide bonds. Cg-ILP has three disulphide bonds like vertebrate Insulin-Like Peptides (ILPs). The last one, Cg-MILP7 has a significant homology with Drosophila ILP7 (DILP7) associated with two additional cysteines allowing the formation of a fourth disulphide bond. The phylogenetic analysis points out that ILPs may be the most ancestral form. Moreover, it appears that ILP7 orthologs are probably anterior to lophotrochozoa and ecdysozoa segregation. In order to investigate the diversity of physiological functions of the oyster IRPs, we combine in silico expression data, qPCR measurements and in situ hybridization. The Cg-ilp transcript, mainly detected in the digestive gland and in the gonadal area, is potentially involved in the control of digestion and gametogenesis. The expression of Cg-mip4 is mainly associated with the larval development. The Cg-mip transcript shared by the Cg-MIP1, 2 and 3, is mainly expressed in visceral ganglia but its expression was also observed in the gonads of mature males. This pattern suggested the key roles of IRPs in the control of sexual reproduction in molluscan species.
Collapse
Affiliation(s)
- Maëva Cherif-Feildel
- Normandy University, Caen, France; University of Caen Normandie, Unity Biology of Organisms and Aquatic Ecosystems (BOREA), MNHN, Sorbonne University, UCN, CNRS, IRD, Esplanade de la Paix, 14032 Caen, France
| | - Clothilde Heude Berthelin
- Normandy University, Caen, France; University of Caen Normandie, Unity Biology of Organisms and Aquatic Ecosystems (BOREA), MNHN, Sorbonne University, UCN, CNRS, IRD, Esplanade de la Paix, 14032 Caen, France
| | - Beatrice Adeline
- Normandy University, Caen, France; University of Caen Normandie, Unity Biology of Organisms and Aquatic Ecosystems (BOREA), MNHN, Sorbonne University, UCN, CNRS, IRD, Esplanade de la Paix, 14032 Caen, France
| | - Guillaume Rivière
- Normandy University, Caen, France; University of Caen Normandie, Unity Biology of Organisms and Aquatic Ecosystems (BOREA), MNHN, Sorbonne University, UCN, CNRS, IRD, Esplanade de la Paix, 14032 Caen, France
| | - Pascal Favrel
- Normandy University, Caen, France; University of Caen Normandie, Unity Biology of Organisms and Aquatic Ecosystems (BOREA), MNHN, Sorbonne University, UCN, CNRS, IRD, Esplanade de la Paix, 14032 Caen, France
| | - Kristell Kellner
- Normandy University, Caen, France; University of Caen Normandie, Unity Biology of Organisms and Aquatic Ecosystems (BOREA), MNHN, Sorbonne University, UCN, CNRS, IRD, Esplanade de la Paix, 14032 Caen, France.
| |
Collapse
|
13
|
Moll L, Roitenberg N, Bejerano-Sagie M, Boocholez H, Carvalhal Marques F, Volovik Y, Elami T, Siddiqui AA, Grushko D, Biram A, Lampert B, Achache H, Ravid T, Tzur YB, Cohen E. The insulin/IGF signaling cascade modulates SUMOylation to regulate aging and proteostasis in Caenorhabditis elegans. eLife 2018; 7:38635. [PMID: 30403374 PMCID: PMC6277199 DOI: 10.7554/elife.38635] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 11/06/2018] [Indexed: 12/02/2022] Open
Abstract
Although aging-regulating pathways were discovered a few decades ago, it is not entirely clear how their activities are orchestrated, to govern lifespan and proteostasis at the organismal level. Here, we utilized the nematode Caenorhabditis elegans to examine whether the alteration of aging, by reducing the activity of the Insulin/IGF signaling (IIS) cascade, affects protein SUMOylation. We found that IIS activity promotes the SUMOylation of the germline protein, CAR-1, thereby shortening lifespan and impairing proteostasis. In contrast, the expression of mutated CAR-1, that cannot be SUMOylated at residue 185, extends lifespan and enhances proteostasis. A mechanistic analysis indicated that CAR-1 mediates its aging-altering functions, at least partially, through the notch-like receptor glp-1. Our findings unveil a novel regulatory axis in which SUMOylation is utilized to integrate the aging-controlling functions of the IIS and of the germline and provide new insights into the roles of SUMOylation in the regulation of organismal aging. Aging may seem inescapable, but there are many factors, from diet to genetic mutations, that can affect this process. In fact, scientists have started to uncover the mechanisms that control and influence this slow decline. For example, in the small worm Caenorhabditis elegans, removing the germs cells – which give rise to eggs – extends the lifespan. Similarly, interfering with the activity of the Insulin/IGF-1 signaling (IIS) pathway leads to a longer life for the animals. However, it is unclear whether these two mechanisms work together, or if they operate in parallel. To explore this, Moll, Roitenberg et al. first looked at how the IIS pathway regulates a type of protein modification known as SUMOylation in C. elegans. Reducing the activity of the IIS pathway slowed down aging in the worms. It also decreased the levels of SUMOylation of certain proteins, including CAR-1, which is found in the structures that produce germ cells. Further experiments showed that stopping the SUMOylation of CAR-1 extended the lifespan of the animals. In fact, replacing the protein with a mutated version of CAR-1 that cannot accept the SUMO element makes the worms live longer and resist a toxic protein that causes Alzheimer’s disease in humans. These results therefore show that, in C. elegans, the IIS pathway and a mechanism that involves CAR-1 in germ cells work together to determine the pace of aging. Further studies are now needed to dissect how the IIS pathway influences SUMOylation, and whether the findings hold true in mammals.
Collapse
Affiliation(s)
- Lorna Moll
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Noa Roitenberg
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Michal Bejerano-Sagie
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Hana Boocholez
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Filipa Carvalhal Marques
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Yuli Volovik
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Tayir Elami
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Atif Ahmed Siddiqui
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Danielle Grushko
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| | - Adi Biram
- Departments of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bar Lampert
- Departments of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hana Achache
- Departments of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tommer Ravid
- Departments of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yonatan B Tzur
- Departments of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ehud Cohen
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem, Israel
| |
Collapse
|
14
|
Kocsisova Z, Mohammad A, Kornfeld K, Schedl T. Cell Cycle Analysis in the C. elegans Germline with the Thymidine Analog EdU. J Vis Exp 2018. [PMID: 30394383 DOI: 10.3791/58339] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cell cycle analysis in eukaryotes frequently utilizes chromosome morphology, expression and/or localization of gene products required for various phases of the cell cycle, or the incorporation of nucleoside analogs. During S-phase, DNA polymerases incorporate thymidine analogs such as EdU or BrdU into chromosomal DNA, marking the cells for analysis. For C. elegans, the nucleoside analog EdU is fed to the worms during regular culture and is compatible with immunofluorescent techniques. The germline of C. elegans is a powerful model system for the studies of signaling pathways, stem cells, meiosis, and cell cycle because it is transparent, genetically facile, and meiotic prophase and cellular differentiation/gametogenesis occur in a linear assembly-like fashion. These features make EdU a great tool to study dynamic aspects of mitotically cycling cells and germline development. This protocol describes how to successfully prepare EdU bacteria, feed them to wild-type C. elegans hermaphrodites, dissect the hermaphrodite gonad, stain for EdU incorporation into DNA, stain with antibodies to detect various cell cycle and developmental markers, image the gonad and analyze the results. The protocol describes the variations in the method and analysis for the measurement of S-phase index, M-phase index, G2 duration, cell cycle duration, rate of meiotic entry, and rate of meiotic prophase progression. This method can be adapted to study the cell cycle or cell history in other tissues, stages, genetic backgrounds, and physiological conditions.
Collapse
Affiliation(s)
- Zuzana Kocsisova
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri; Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
| | - Ariz Mohammad
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri
| | - Tim Schedl
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri;
| |
Collapse
|
15
|
Abstract
During development, stem cells generate all of the differentiated cells that populate our
tissues and organs. Stem cells are also responsible for tissue turnover and repair in
adults, and as such, they hold tremendous promise for regenerative therapy. Aging,
however, impairs the function of stem cells and is thus a significant roadblock to using
stem cells for therapy. Paradoxically, the patients who would benefit the most from
regenerative therapies are usually advanced in age. The use of stem cells from young
donors or the rejuvenation of aged patient-derived stem cells may represent part of a
solution. Nonetheless, the transplantation success of young or rejuvenated stem cells in
aged patients is still problematic, since stem cell function is greatly influenced by
extrinsic factors that become unsupportive with age. This article briefly reviews how
aging impairs stem cell function, and how this has an impact on the use of stem cells for
therapy.
Collapse
Affiliation(s)
- Patrick Narbonne
- Département de Biologie Médicale, Université du Québec à Trois-Rivières, Canada.,Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Faculté de Médecine, Université Laval, Canada
| |
Collapse
|
16
|
Javadi A, Deevi RK, Evergren E, Blondel-Tepaz E, Baillie GS, Scott MGH, Campbell FC. PTEN controls glandular morphogenesis through a juxtamembrane β-Arrestin1/ARHGAP21 scaffolding complex. eLife 2017; 6:e24578. [PMID: 28749339 PMCID: PMC5576923 DOI: 10.7554/elife.24578] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 07/24/2017] [Indexed: 01/01/2023] Open
Abstract
PTEN controls three-dimensional (3D) glandular morphogenesis by coupling juxtamembrane signaling to mitotic spindle machinery. While molecular mechanisms remain unclear, PTEN interacts through its C2 membrane-binding domain with the scaffold protein β-Arrestin1. Because β-Arrestin1 binds and suppresses the Cdc42 GTPase-activating protein ARHGAP21, we hypothesize that PTEN controls Cdc42 -dependent morphogenic processes through a β-Arrestin1-ARHGAP21 complex. Here, we show that PTEN knockdown (KD) impairs β-Arrestin1 membrane localization, β-Arrestin1-ARHGAP21 interactions, Cdc42 activation, mitotic spindle orientation and 3D glandular morphogenesis. Effects of PTEN deficiency were phenocopied by β-Arrestin1 KD or inhibition of β-Arrestin1-ARHGAP21 interactions. Conversely, silencing of ARHGAP21 enhanced Cdc42 activation and rescued aberrant morphogenic processes of PTEN-deficient cultures. Expression of the PTEN C2 domain mimicked effects of full-length PTEN but a membrane-binding defective mutant of the C2 domain abrogated these properties. Our results show that PTEN controls multicellular assembly through a membrane-associated regulatory protein complex composed of β-Arrestin1, ARHGAP21 and Cdc42.
Collapse
Affiliation(s)
- Arman Javadi
- Centre for Cancer Research and Cell BiologyQueen’s University of BelfastBelfastUnited Kingdom
| | - Ravi K Deevi
- Centre for Cancer Research and Cell BiologyQueen’s University of BelfastBelfastUnited Kingdom
| | - Emma Evergren
- Centre for Cancer Research and Cell BiologyQueen’s University of BelfastBelfastUnited Kingdom
| | - Elodie Blondel-Tepaz
- Inserm, U1016, Institut CochinParisFrance
- CNRS, UMR8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - George S Baillie
- Institute of Cardiovascular and Medical Science, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowScotland
| | - Mark GH Scott
- Inserm, U1016, Institut CochinParisFrance
- CNRS, UMR8104ParisFrance
- Univ. Paris Descartes, Sorbonne Paris CitéParisFrance
| | - Frederick C Campbell
- Centre for Cancer Research and Cell BiologyQueen’s University of BelfastBelfastUnited Kingdom
| |
Collapse
|
17
|
Zhang C, Wu X, Zhang B, Chen Q, Liu M, Xin D, Qi Z, Li S, Ma Y, Wang L, Jin Y, Li W, Wu X, Su AY. Functional analysis of the GmESR1 gene associated with soybean regeneration. PLoS One 2017; 12:e0175656. [PMID: 28403182 PMCID: PMC5389854 DOI: 10.1371/journal.pone.0175656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 03/29/2017] [Indexed: 11/19/2022] Open
Abstract
Plant regeneration can occur via in vitro tissue culture through somatic embryogenesis or de novo shoot organogenesis. Transformation of soybean (Glycine max) is difficult, hence optimization of the transformation system for soybean regeneration is required. This study investigated ENHANCER OF SHOOT REGENERATION 1 (GmESR1), a soybean transcription factor that targets regeneration-associated genes. Sequence analysis showed that GmESR1 contained a conserved 57 amino acid APETALA 2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) DNA-binding domain. The relative expression level of GmESR1 was highest in young embryos, flowers and stems in the soybean cultivar 'Dongnong 50'. To examine the function of GmESR1, transgenic Arabidopsis (Arabidopsis thaliana) and soybean plants overexpressing GmESR1 were generated. In Arabidopsis, overexpression of GmESR1 resulted in accelerated seed germination, and seedling shoot and root elongation. In soybean overexpression of GmESR1 also led to faster seed germination, and shoot and root elongation. GmESR1 specifically bound to the GCC-box. The results provide a foundation for the establishment of an efficient and stable transformation system for soybean.
Collapse
Affiliation(s)
- Chao Zhang
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Xiaodong Wu
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Binbin Zhang
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Qingshan Chen
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Ming Liu
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Dawei Xin
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Zhaoming Qi
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Sinan Li
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Yanlong Ma
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Lingshuang Wang
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Yangmei Jin
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Wenbin Li
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - Xiaoxia Wu
- Soybean Research Institute, Key Laboratory of Soybean Biology of Chinese Education Ministry, Northeast Agricultural University, Harbin, Heilongjiang province, People’s Republic of China
| | - An-yu Su
- College of Resources and Environment, Northeast Agricultural University. Harbin, Heilongjiang province, People’s Republic of China
| |
Collapse
|
18
|
Narbonne P, Maddox PS, Labbé JC. DAF-18/PTEN signals through AAK-1/AMPK to inhibit MPK-1/MAPK in feedback control of germline stem cell proliferation. PLoS Genet 2017; 13:e1006738. [PMID: 28410423 PMCID: PMC5409174 DOI: 10.1371/journal.pgen.1006738] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 04/28/2017] [Accepted: 04/05/2017] [Indexed: 11/19/2022] Open
Abstract
Under replete growth conditions, abundant nutrient uptake leads to the systemic activation of insulin/IGF-1 signalling (IIS) and the promotion of stem cell growth/proliferation. Activated IIS can stimulate the ERK/MAPK pathway, the activation of which also supports optimal stem cell proliferation in various systems. Stem cell proliferation rates can further be locally refined to meet the resident tissue's need for differentiated progeny. We have recently shown that the accumulation of mature oocytes in the C. elegans germ line, through DAF-18/PTEN, inhibits adult germline stem cell (GSC) proliferation, despite high systemic IIS activation. We show here that this feedback occurs through a novel cryptic signalling pathway that requires PAR-4/LKB1, AAK-1/AMPK and PAR-5/14-3-3 to inhibit the activity of MPK-1/MAPK, antagonize IIS, and inhibit both GSC proliferation and the production of additional oocytes. Interestingly, our results imply that DAF-18/PTEN, through PAR-4/LKB1, can activate AAK-1/AMPK in the absence of apparent energy stress. As all components are conserved, similar signalling cascades may regulate stem cell activities in other organisms and be widely implicated in cancer.
Collapse
Affiliation(s)
- Patrick Narbonne
- Department of Pathology and Cell Biology, Institut de Recherche en Immunologie et en Cancérologie (IRIC), Université de Montréal, Montréal, Québec, Canada
| | - Paul S. Maddox
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, United States of America
| | - Jean-Claude Labbé
- Department of Pathology and Cell Biology, Institut de Recherche en Immunologie et en Cancérologie (IRIC), Université de Montréal, Montréal, Québec, Canada
| |
Collapse
|
19
|
Cinquin A, Chiang M, Paz A, Hallman S, Yuan O, Vysniauskaite I, Fowlkes CC, Cinquin O. Intermittent Stem Cell Cycling Balances Self-Renewal and Senescence of the C. elegans Germ Line. PLoS Genet 2016; 12:e1005985. [PMID: 27077385 PMCID: PMC4831802 DOI: 10.1371/journal.pgen.1005985] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/18/2016] [Indexed: 11/22/2022] Open
Abstract
Self-renewing organs often experience a decline in function in the course of aging. It is unclear whether chronological age or external factors control this decline, or whether it is driven by stem cell self-renewal—for example, because cycling cells exhaust their replicative capacity and become senescent. Here we assay the relationship between stem cell cycling and senescence in the Caenorhabditis elegans reproductive system, defining this senescence as the progressive decline in “reproductive capacity,” i.e. in the number of progeny that can be produced until cessation of reproduction. We show that stem cell cycling diminishes remaining reproductive capacity, at least in part through the DNA damage response. Paradoxically, gonads kept under conditions that preclude reproduction keep cycling and producing cells that undergo apoptosis or are laid as unfertilized gametes, thus squandering reproductive capacity. We show that continued activity is in fact beneficial inasmuch as gonads that are active when reproduction is initiated have more sustained early progeny production. Intriguingly, continued cycling is intermittent—gonads switch between active and dormant states—and in all likelihood stochastic. Other organs face tradeoffs whereby stem cell cycling has the beneficial effect of providing freshly-differentiated cells and the detrimental effect of increasing the likelihood of cancer or senescence; stochastic stem cell cycling may allow for a subset of cells to preserve proliferative potential in old age, which may implement a strategy to deal with uncertainty as to the total amount of proliferation to be undergone over an organism’s lifespan. Stem cell cycling is expected to be beneficial because it helps delay aging, by ensuring organ self-renewal. Yet stem cell cycling is best used sparingly: cycling likely causes mutation accumulation—increasing the likelihood of cancer—and may eventually cause stem cells to senesce and thus stop contributing to organ self renewal. It is unknown how self-renewing organs make tradeoffs between benefits and drawbacks of stem cell cycling. Here we use the C. elegans reproductive system as a model organ. We characterize benefits and drawbacks of stem cell cycling—which are keeping worms primed for reproduction, and reducing the number of future progeny worms may bear, respectively. We show that, under specific conditions of reproductive inactivity, stem cells switch back and forth between active and dormant states; the timing of these switches, whose genetic control we start delineating, appears random. This randomness may help explain why populations of aging, reproductively-inactive worms experience an increase in the variability of their reproductive capacity. Stochastic stem cell cycling may underlie tradeoffs between self-renewal and senescence in other organs.
Collapse
Affiliation(s)
- Amanda Cinquin
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
| | - Michael Chiang
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
| | - Adrian Paz
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
| | - Sam Hallman
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
- Department of Computer Science, University of California, Irvine, Irvine, California, United States of America
| | - Oliver Yuan
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
| | - Indre Vysniauskaite
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
| | - Charless C. Fowlkes
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
- Department of Computer Science, University of California, Irvine, Irvine, California, United States of America
| | - Olivier Cinquin
- Department of Developmental & Cell Biology, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
- * E-mail:
| |
Collapse
|