1
|
Özpolat BD. Annelids as models of germ cell and gonad regeneration. J Exp Zool B Mol Dev Evol 2024; 342:126-143. [PMID: 38078561 PMCID: PMC11060932 DOI: 10.1002/jez.b.23233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/20/2023]
Abstract
Germ cells (reproductive cells and their progenitors) give rise to the next generation in sexually reproducing organisms. The loss or removal of germ cells often leads to sterility in established research organisms such as the fruit fly, nematodes, frog, and mouse. The failure to regenerate germ cells in these organisms reinforced the dogma of germline-soma barrier in which germ cells are set-aside during embryogenesis and cannot be replaced by somatic cells. However, in stark contrast, many animals including segmented worms (annelids), hydrozoans, planaria, sea stars, sea urchins, and tunicates can regenerate germ cells. Here I review germ cell and gonad regeneration in annelids, a rich history of research that dates back to the early 20th century in this highly regenerative group. Examples include annelids from across the annelid phylogeny, across developmental stages, and reproductive strategies. Adult annelids regenerate germ cells as a part of regeneration, grafting, and asexual reproduction. Annelids can also recover germ cells after ablation of germ cell progenitors in the embryos. I present a framework to investigate cellular sources of germ cell regeneration in annelids, and discuss the literature that supports different possibilities within this framework, where germ-soma separation may or may not be preserved. With contemporary genetic-lineage tracing and bioinformatics tools, and several genetically enabled annelid models, we are at the brink of answering the big questions that puzzled many for over more than a century.
Collapse
Affiliation(s)
- B Duygu Özpolat
- Department of Biology, Washington University in St. Louis, St. Louis, United States, United States
| |
Collapse
|
2
|
Aubier TG, Galipaud M. Senescence evolution under the catastrophic accumulation of deleterious mutations. Evol Lett 2024; 8:212-221. [PMID: 38525026 PMCID: PMC10959475 DOI: 10.1093/evlett/qrad050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/25/2023] [Accepted: 09/19/2023] [Indexed: 03/26/2024] Open
Abstract
For aging to evolve, selection against mortality must decrease with age. This prevailing view in the evolutionary theory of senescence posits that mutations with deleterious effects happening late in life-when purging selection is weak-may become fixed via genetic drift in the germline, and produce a senescent phenotype. Theory, however, has focused primarily on growing populations and the fate of single deleterious mutations. In a mathematical model, we demonstrate that relaxing both of these simplifying assumptions leads to unrealistic outcomes. In density-regulated populations, previously fixed deleterious mutations should promote the fixation of other deleterious mutations that lead to senescence at ever younger ages, until death necessarily occurs at sexual maturity. This sequential fixation of deleterious mutations is not promoted by a decrease in population size, but is due to a change in the strength of selection. In an individual-based model, we also show that such evolutionary dynamics should lead to the extinction of most populations. Our models therefore make rather unrealistic predictions, underlining the need for a reappraisal of current theories. In this respect, we have further assumed in our models that the deleterious effects of mutations can only occur at certain ages, marked, for instance, by somatic or physiological changes. Under this condition, we show that the catastrophic accumulation of deleterious mutations in the germline can stop. This new finding emphasizes the importance of investigating somatic factors, as well as other mechanisms underlying the deleterious effects of mutations, to understand senescence evolution. More generally, our model therefore establishes that patterns of senescence in nature depend not only on the decrease in selection strength with age but also on any mechanism that stops the catastrophic accumulation of mutations.
Collapse
Affiliation(s)
- Thomas G Aubier
- Laboratoire Évolution and Diversification Biologique, Université Paul Sabatier Toulouse III, UMR 5174, CNRS/IRD, 31077 Toulouse, France
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Matthias Galipaud
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Swiss Data Science Center, ETH, Zurich, Switzerland
| |
Collapse
|
3
|
Kawai F. Somatic ion channels and action potentials in olfactory receptor cells and vomeronasal receptor cells. J Neurophysiol 2024; 131:455-471. [PMID: 38264787 DOI: 10.1152/jn.00137.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 01/10/2024] [Accepted: 01/17/2024] [Indexed: 01/25/2024] Open
Abstract
Olfactory receptor cells are primary sensory neurons that catch odor molecules in the olfactory system, and vomeronasal receptor cells catch pheromones in the vomeronasal system. When odor or pheromone molecules bind to receptor proteins expressed on the membrane of the olfactory cilia or vomeronasal microvilli, receptor potentials are generated in their receptor cells. This initial excitation is transmitted to the soma via dendrites, and action potentials are generated in the soma and/or axon and transmitted to the central nervous system. Thus, olfactory and vomeronasal receptor cells play an important role in converting chemical signals into electrical signals. In this review, the electrophysiological characteristics of ion channels in the somatic membrane of olfactory receptor cells and vomeronasal receptor cells in various species are described and the differences between the action potential dynamics of olfactory receptor cells and vomeronasal receptor cells are compared.
Collapse
Affiliation(s)
- Fusao Kawai
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan
| |
Collapse
|
4
|
Tyagi S, Higerd-Rusli GP, Ghovanloo MR, Dib-Hajj F, Zhao P, Liu S, Kim DH, Shim JS, Park KS, Waxman SG, Choi JS, Dib-Hajj SD. Compartment-specific regulation of Na V1.7 in sensory neurons after acute exposure to TNF-α. Cell Rep 2024; 43:113685. [PMID: 38261513 PMCID: PMC10947185 DOI: 10.1016/j.celrep.2024.113685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/09/2023] [Accepted: 01/02/2024] [Indexed: 01/25/2024] Open
Abstract
Tumor necrosis factor α (TNF-α) is a major pro-inflammatory cytokine, important in many diseases, that sensitizes nociceptors through its action on a variety of ion channels, including voltage-gated sodium (NaV) channels. We show here that TNF-α acutely upregulates sensory neuron excitability and current density of threshold channel NaV1.7. Using electrophysiological recordings and live imaging, we demonstrate that this effect on NaV1.7 is mediated by p38 MAPK and identify serine 110 in the channel's N terminus as the phospho-acceptor site, which triggers NaV1.7 channel insertion into the somatic membrane. We also show that the N terminus of NaV1.7 is sufficient to mediate this effect. Although acute TNF-α treatment increases NaV1.7-carrying vesicle accumulation at axonal endings, we did not observe increased channel insertion into the axonal membrane. These results identify molecular determinants of TNF-α-mediated regulation of NaV1.7 in sensory neurons and demonstrate compartment-specific effects of TNF-α on channel insertion in the neuronal plasma membrane.
Collapse
Affiliation(s)
- Sidharth Tyagi
- Medical Scientist Training Program, Yale School of Medicine, New Haven, CT 06511, USA; Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA.
| | - Grant P Higerd-Rusli
- Medical Scientist Training Program, Yale School of Medicine, New Haven, CT 06511, USA; Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Mohammad-Reza Ghovanloo
- Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Fadia Dib-Hajj
- Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Peng Zhao
- Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Shujun Liu
- Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Dong-Hyun Kim
- Integrated Research Institute of Pharmaceutical Science, College of Pharmacy, The Catholic University of Korea, Bucheon 14662, South Korea; New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu 41061, South Korea
| | - Ji Seon Shim
- Department of Physiology, Kyung Hee University School of Medicine, Seoul 02447, South Korea
| | - Kang-Sik Park
- Department of Physiology, Kyung Hee University School of Medicine, Seoul 02447, South Korea
| | - Stephen G Waxman
- Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA.
| | - Jin-Sung Choi
- Integrated Research Institute of Pharmaceutical Science, College of Pharmacy, The Catholic University of Korea, Bucheon 14662, South Korea.
| | - Sulayman D Dib-Hajj
- Center for Neuroscience and Regeneration Research, West Haven, CT 06516, USA; Department of Neurology, Yale School of Medicine, New Haven, CT 06516, USA; Center for Restoration of Nervous System Function, VA Connecticut Healthcare System, West Haven, CT 06516, USA.
| |
Collapse
|
5
|
Vollrath F. Uncoupling elephant TP53 and cancer. Trends Ecol Evol 2023:S0169-5347(23)00135-0. [PMID: 37385845 DOI: 10.1016/j.tree.2023.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 07/01/2023]
Abstract
Elephant testicles do not descend, with implications for sperm production being hot enough to compromise germline DNA replication/repair. Uniquely, elephants also possess 20 copies of a gene encoding for the p53 protein. Did elephants evolve multiplication of the TP53 gene complex to protect their germline rather than to fight cancer?
Collapse
Affiliation(s)
- Fritz Vollrath
- Department of Biology, University of Oxford, OX1 3PS, UK.
| |
Collapse
|
6
|
Ivimey-Cook ER, Murray DS, de Coriolis JC, Edden N, Immler S, Maklakov AA. Fasting increases investment in soma upon refeeding at the cost of gamete quality in zebrafish. Proc Biol Sci 2023; 290:20221556. [PMID: 37040805 PMCID: PMC10089719 DOI: 10.1098/rspb.2022.1556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023] Open
Abstract
Fasting increases lifespan in invertebrates, improves biomarkers of health in vertebrates and is increasingly proposed as a promising route to improve human health. Nevertheless, little is known about how fasted animals use resources upon refeeding, and how such decisions affect putative trade-offs between somatic growth and repair, reproduction and gamete quality. Such fasting-induced trade-offs are based on strong theoretical foundations and have been recently discovered in invertebrates, but the data on vertebrates are lacking. Here, we report that fasted female zebrafish, Danio rerio, increase investment in soma upon refeeding, but it comes at a cost of egg quality. Specifically, an increase in fin regrowth was accompanied by a reduction in 24 h post-fertilization offspring survival. Refed males showed a reduction in sperm velocity and impaired 24 h post-fertilization offspring survival. These findings underscore the necessity of considering the impact on reproduction when assessing evolutionary and biomedical implications of lifespan-extending treatments in females and males and call for careful evaluation of the effects of intermittent fasting on fertilization.
Collapse
Affiliation(s)
- Edward R Ivimey-Cook
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - David S Murray
- Collaborative Centre for Sustainable Use of the Seas (CCSUS), School of Environmental Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
- The Centre for Environment, Fisheries and Aquaculture Science (Cefas), Lowestoft, Suffolk NR33 0HT, UK
| | | | - Nathan Edden
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
| | - Simone Immler
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
| | - Alexei A Maklakov
- School of Biological Sciences, University of East Anglia, Norfolk NR4 7TJ, UK
| |
Collapse
|
7
|
Wessel GM, Morita S, Oulhen N. Somatic cell conversion to a germ cell lineage: A violation or a revelation? J Exp Zool B Mol Dev Evol 2021; 336:666-679. [PMID: 32445519 PMCID: PMC7680723 DOI: 10.1002/jez.b.22952] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/29/2022]
Abstract
The germline is unique and immortal (or at least its genome is). It is able to perform unique jobs (meiosis) and is selected for genetic changes. Part of being this special also means that entry into the germline club is restricted and cells of the soma are always left out. However, the recent evidence from multiple animals now suggests that somatic cells may join the club and become germline cells in an animal when the original germline is removed. This "violation" may have garnered acceptance by the observation that iPScells, originating experimentally from somatic cells of an adult, can form reproductively successful eggs and sperm, all in vitro. Each of the genes and their functions used to induce pluripotentiality are found normally in the cell and the in vitro conditions to direct germline commitment replicate conditions in vivo. Here, we discuss evidence from three different animals: an ascidian, a segmented worm, and a sea urchin; and that the cells of a somatic cell lineage can convert into the germline in vivo. We discuss the consequences of such transitions and provide thoughts as how this process may have equal precision to the original germline formation of an embryo.
Collapse
Affiliation(s)
- Gary M. Wessel
- Department of Molecular and Cellular Biology, Brown University, Providence RI 02912 USA
| | - Shumpei Morita
- Department of Molecular and Cellular Biology, Brown University, Providence RI 02912 USA
| | - Nathalie Oulhen
- Department of Molecular and Cellular Biology, Brown University, Providence RI 02912 USA
| |
Collapse
|
8
|
Abstract
Between the 1930s and 1960s, evolutionary geneticists worked out the basic principles of why organisms age. Despite much progress in the evolutionary biology of ageing since that time, however, many puzzles remain. The perhaps most fundamental of these is the question of which organisms should exhibit senescence and which should not (or which should age rapidly and which should not). The evolutionary origin of ageing from a non-senescent state has been conceptually framed, for example, in terms of the separation between germ-line and soma, the distinction between parents and their offspring, and-in unicellular organisms-the unequal distribution of cellular damage at cell division. These ideas seem to be closely related to the concept of 'division of labour' between reproduction and somatic maintenance. Here, we review these concepts and develop a toy model to explore the importance of such asymmetries for the evolution of senescence. We apply our model to the simplest case of a multicellular system: an organism consisting of two totipotent cells. Notably, we find that in organisms which reproduce symmetrically and partition damage equally, senescence is still able to evolve, contrary to previous claims. Our results might have some bearing on understanding the origin of the germ-line-soma separation and the evolution of senescence in multicellular organisms and in colonial species consisting of multiple types of individuals, such as, for example, eusocial insects with their different castes. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'
Collapse
Affiliation(s)
- Ido Pen
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| |
Collapse
|
9
|
Liu C, Liu J, Liu C, Zhou Q, Zhou Y, Zhang B, Saijilafu. The intrinsic axon regenerative properties of mature neurons after injury. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1-9. [PMID: 33258872 DOI: 10.1093/abbs/gmaa148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Indexed: 01/07/2023] Open
Abstract
Thousands of nerve injuries occur in the world each year. Axon regeneration is a very critical process for the restoration of the injured nervous system's function. However, the precise molecular mechanism or signaling cascades that control axon regeneration are not clearly understood, especially in mammals. Therefore, there is almost no ideal treatment method to repair the nervous system's injury until now. Mammalian axonal regeneration requires multiple signaling pathways to coordinately regulate gene expression in soma and assembly of the cytoskeleton protein in the growth cone. A better understanding of their molecular mechanisms, such as axon regeneration regulatory signaling cascades, will be helpful in developing new treatment strategies for promoting axon regeneration. In this review, we mainly focus on describing these regeneration-associated signaling cascades, which regulate axon regeneration.
Collapse
Affiliation(s)
- Chunfeng Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Jinlian Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Chaoqun Liu
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Qing Zhou
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Yaodong Zhou
- Department of Orthopedic Surgery, Suzhou Kowloon Hospital, Shanghai Jiaotong University Medical School, Suzhou 215000, China
| | - Boyin Zhang
- Orthopedics Surgery Department, China-Japan Union Hospital of Jilin University, Changchun 130033, China
| | - Saijilafu
- Department of Orthopaedics, The First Affiliated Hospital, Orthopaedic Institute, Soochow University, Suzhou 215007, China
| |
Collapse
|
10
|
Abstract
The Weismann barrier has long been regarded as a basic tenet of biology. However, upon close examination of its historical origins and August Weismann's own writings, questions arise as to whether such a status is warranted. As scientific research has advanced, the persistence of the concept of the barrier has left us with the same dichotomies Weismann contended with over 100 years ago: germ or soma, gene or environment, hard or soft inheritance. These dichotomies distract from the more important questions we need to address going forward. In this review, we will examine the theories that have shaped Weismann's thinking, how the concept of the Weismann barrier emerged, and the limitations that it carries. We will contrast the principles underlying the barrier with recent and less recent findings in developmental biology and transgenerational epigenetic inheritance that have profoundly eroded the oppositional view of germline vs. soma. Discarding the barrier allows us to examine the interactive processes and their response to environmental context that generate germ cells in the first place, determine the entirety of what is inherited through them, and set the trajectory for the health status of the progeny they bear.
Collapse
Affiliation(s)
- Abigail P. Bline
- Molecular Toxicology Interdepartmental Program, University of California Los Angeles, Los Angeles, CA 90095, USA;
| | - Anne Le Goff
- UCLA EpiCenter on Epigenetics, Reproduction & Society, University of California Los Angeles, Los Angeles, CA 90095, USA;
- Institute for Society & Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Patrick Allard
- Molecular Toxicology Interdepartmental Program, University of California Los Angeles, Los Angeles, CA 90095, USA;
- UCLA EpiCenter on Epigenetics, Reproduction & Society, University of California Los Angeles, Los Angeles, CA 90095, USA;
- Institute for Society & Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
11
|
Shami AN, Zheng X, Munyoki SK, Ma Q, Manske GL, Green CD, Sukhwani M, Orwig KE, Li JZ, Hammoud SS. Single-Cell RNA Sequencing of Human, Macaque, and Mouse Testes Uncovers Conserved and Divergent Features of Mammalian Spermatogenesis. Dev Cell 2020; 54:529-547.e12. [PMID: 32504559 DOI: 10.1016/j.devcel.2020.05.010] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 03/10/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022]
Abstract
Spermatogenesis is a highly regulated process that produces sperm to transmit genetic information to the next generation. Although extensively studied in mice, our current understanding of primate spermatogenesis is limited to populations defined by state-specific markers from rodent data. As between-species differences have been reported in the duration and differentiation hierarchy of this process, it remains unclear how molecular markers and cell states are conserved or have diverged from mice to man. To address this challenge, we employ single-cell RNA sequencing to identify transcriptional signatures of major germ and somatic cell types of the testes in human, macaque, and mice. This approach reveals similarities and differences in expression throughout spermatogenesis, including the stem/progenitor pool of spermatogonia, markers of differentiation, potential regulators of meiosis, RNA turnover during spermatid differentiation, and germ cell-soma communication. These datasets provide a rich foundation for future targeted mechanistic studies of primate germ cell development and in vitro gametogenesis.
Collapse
Affiliation(s)
| | - Xianing Zheng
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Sarah K Munyoki
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Integrative Systems Biology Graduate Program, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Qianyi Ma
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Gabriel L Manske
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA
| | | | - Meena Sukhwani
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Integrative Systems Biology Graduate Program, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kyle E Orwig
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Integrative Systems Biology Graduate Program, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Jun Z Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA.
| | - Saher Sue Hammoud
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA; Department of Urology, University of Michigan, Ann Arbor, MI, USA.
| |
Collapse
|
12
|
Hudish LI, Bubak A, Triolo TM, Niemeyer CS, Lorberbaum DS, Sussel L, Nagel M, Taliaferro JM, Russ HA. Modeling Hypoxia-Induced Neuropathies Using a Fast and Scalable Human Motor Neuron Differentiation System. Stem Cell Reports 2020; 14:1033-1043. [PMID: 32386561 PMCID: PMC7355142 DOI: 10.1016/j.stemcr.2020.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 12/13/2022] Open
Abstract
Human motor neuron (MN) diseases encompass a spectrum of disorders. A critical barrier to dissecting disease mechanisms is the lack of appropriate human MN models. Here, we describe a scalable, suspension-based differentiation system to generate functional human MN diseases in 3 weeks. Using this model, we translated recent findings that mRNA mis-localization plays a role in disease development to the human context by establishing a membrane-based system that allows efficient fractionation of MN cell soma and neurites. In response to hypoxia, used to mimic diabetic neuropathies, MNs upregulated mitochondrial transcripts in neurites; however, mitochondria were decreased. These data suggest that hypoxia may disrupt translation of mitochondrial mRNA, potentially leading to neurite damage and development of neuropathies. We report the development of a novel human MN model system to investigate mechanisms of disease affecting soma and/or neurites that facilitates the rapid generation and testing of patient-specific MN diseases.
Collapse
Affiliation(s)
- Laura I Hudish
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrew Bubak
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Taylor M Triolo
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Christy S Niemeyer
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - David S Lorberbaum
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Lori Sussel
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Maria Nagel
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - J Matthew Taliaferro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Holger A Russ
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| |
Collapse
|
13
|
Lynch WB, Tschumi CW, Sharpe AL, Branch SY, Chen C, Ge G, Li S, Beckstead MJ. Progressively disrupted somatodendritic morphology in dopamine neurons in a mouse Parkinson's model. Mov Disord 2018; 33:1928-1937. [PMID: 30440089 DOI: 10.1002/mds.27541] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/10/2018] [Accepted: 09/16/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Parkinson's disease is characterized by the progressive loss of dopamine neurons in the substantia nigra, leading to severe motor deficits. Although the disease likely begins to develop years before observable motor symptoms, the specific morphological and functional alterations involved are poorly understood. OBJECTIVES MitoPark mice lack the gene coding for mitochondrial transcription factor A specifically in dopamine neurons, which over time produces a progressive decline of neuronal function and related behavior that phenotypically mirrors human parkinsonism. Our previous work identified a progressive decrease in cell capacitance in dopamine neurons from MitoPark mice, possibly suggesting reduced membrane surface area. We therefore sought to identify and quantify somatodendritic parameters in this model across age. METHODS We used whole-cell patch clamp and fluorescent labeling to quantify somatodendritic morphology of single, neurobiotin-filled dopamine neurons in acutely isolated brain slices from MitoPark mice. RESULTS We found that MitoPark mice exhibit an adult-onset, age-dependent reduction of neuritic branching and soma size in dopamine neurons. This decline proceeds similarly in MitoPark mice of both sexes, but does not begin until after the age that early decrements in ion channel physiology and behavior have previously been observed. CONCLUSIONS A progressive and severe decline in somatodendritic morphology occurs prior to cell death, but is not responsible for the subtle decrements observable in the earliest stages of neurodegeneration. This work could help identify the ideal time window for specific treatments to halt disease progression and avert debilitating motor deficits in Parkinson's patients. © 2018 International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- William B Lynch
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Christopher W Tschumi
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.,Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas, USA
| | - Amanda L Sharpe
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.,Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, Oklahoma, USA
| | - Sarah Y Branch
- Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas, USA
| | - Cang Chen
- Department of Medicine, University of Texas Health, San Antonio, Texas, USA
| | - Guo Ge
- Department of Medicine, University of Texas Health, San Antonio, Texas, USA
| | - Senlin Li
- Department of Medicine, University of Texas Health, San Antonio, Texas, USA
| | - Michael J Beckstead
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.,Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, Texas, USA
| |
Collapse
|
14
|
Argyridou E, Parsch J. Regulation of the X Chromosome in the Germline and Soma of Drosophila melanogaster Males. Genes (Basel) 2018; 9:genes9050242. [PMID: 29734690 PMCID: PMC5977182 DOI: 10.3390/genes9050242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/22/2022] Open
Abstract
During the evolution of heteromorphic sex chromosomes, the sex-specific Y chromosome degenerates, while the X chromosome evolves new mechanisms of regulation. Using bioinformatic and experimental approaches, we investigate the expression of the X chromosome in Drosophila melanogaster. We observe nearly complete X chromosome dosage compensation in male somatic tissues, but not in testis. The X chromosome contains disproportionately fewer genes with high expression in testis than the autosomes, even after accounting for the lack of dosage compensation, which suggests that another mechanism suppresses their expression in the male germline. This is consistent with studies of reporter genes and transposed genes, which find that the same gene has higher expression when autosomal than when X-linked. Using a new reporter gene that is expressed in both testis and somatic tissues, we find that the suppression of X-linked gene expression is limited to genes with high expression in testis and that the extent of the suppression is positively correlated with expression level.
Collapse
Affiliation(s)
- Eliza Argyridou
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Grosshaderner Str. 2, 82152 Planegg-Martinsried, Germany.
| | - John Parsch
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Grosshaderner Str. 2, 82152 Planegg-Martinsried, Germany.
| |
Collapse
|
15
|
Abstract
Differentiation within multicellular organisms is controlled by epigenetic markers transmitted across cell division. The process of differentiation will modify these epigenetic markers so that information that one cell type possesses can be lost in the transition to another. Many of the systems that encode these markers also exist in unicellular organisms but do not control differentiation. Thus, during the evolution of multicellularity, epigenetic inheritance systems were probably exapted for their current use in differentiation. We show that the simultaneous use of an information carrier for differentiation and transmission across generations can lead to the evolution of cell types that do not directly contribute to the progeny of the organism and ergo a germ-soma distinction. This shows that an intrinsic instability during a transition from unicellularity to multicellularity may contribute to widespread evolution of a germline and its maintenance, a phenomenon also relevant to the evolution of eusociality. The difference in epigenetic information contents between different cell lines in a multicellular organism is also relevant for the full-success cloning of higher animals, as well as for the maintenance of single germlines over evolutionary timescales.This article is part of the themed issue 'The major synthetic evolutionary transitions'.
Collapse
Affiliation(s)
| | - Eric Libby
- Santa Fe Institute, Santa Fe, NM 87501, USA
| |
Collapse
|
16
|
Narayanan RT, Udvary D, Oberlaender M. Cell Type-Specific Structural Organization of the Six Layers in Rat Barrel Cortex. Front Neuroanat 2017; 11:91. [PMID: 29081739 PMCID: PMC5645532 DOI: 10.3389/fnana.2017.00091] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/28/2017] [Indexed: 01/18/2023] Open
Abstract
The cytoarchitectonic subdivision of the neocortex into six layers is often used to describe the organization of the cortical circuitry, sensory-evoked signal flow or cortical functions. However, each layer comprises neuronal cell types that have different genetic, functional and/or structural properties. Here, we reanalyze structural data from some of our recent work in the posterior-medial barrel-subfield of the vibrissal part of rat primary somatosensory cortex (vS1). We quantify the degree to which somata, dendrites and axons of the 10 major excitatory cell types of the cortex are distributed with respect to the cytoarchitectonic organization of vS1. We show that within each layer, somata of multiple cell types intermingle, but that each cell type displays dendrite and axon distributions that are aligned to specific cytoarchitectonic landmarks. The resultant quantification of the structural composition of each layer in terms of the cell type-specific number of somata, dendritic and axonal path lengths will aid future studies to bridge between layer- and cell type-specific analyses.
Collapse
Affiliation(s)
- Rajeevan T Narayanan
- Max Planck Group: In Silico Brain Sciences, Center of Advanced European Studies and Research, Bonn, Germany
| | - Daniel Udvary
- Max Planck Group: In Silico Brain Sciences, Center of Advanced European Studies and Research, Bonn, Germany
| | - Marcel Oberlaender
- Max Planck Group: In Silico Brain Sciences, Center of Advanced European Studies and Research, Bonn, Germany
| |
Collapse
|
17
|
Koufopanou V, Bell G. DEVELOPMENTAL MUTANTS OF VOLVOX: DOES MUTATION RECREATE THE PATTERNS OF PHYLOGENETIC DIVERSITY? Evolution 2017; 45:1806-1822. [PMID: 28563961 DOI: 10.1111/j.1558-5646.1991.tb02689.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/1990] [Accepted: 04/19/1991] [Indexed: 11/29/2022]
Abstract
The nature of the variation which is created by mutation can show how the direction of evolution is constrained by internal biases arising from development and pre-existing design. We have attempted to quantify these biases by measuring eight life history characters in developmental mutants of Volvox carteri. Most of the mutants in our sample were inferior to the wild type, but deviated by less than tenfold from the wild-type mean. Characters differed in mutability, suggesting different levels of canalisation. Most correlations between life history characters among strains were positive, but there was a significant negative correlation between the size and the number of reproductive cells, suggesting an upper limit to the total quantity of germ produced by individuals. The most extreme phenotypes in our sample were very vigorous, showing that not all mutations of large effect are unconditionally deleterious. We investigated the effect of developmental constraints on the course of evolution by comparing the variance and covariance patterns among mutant strains with those among species in the family Volvocaceae. A close correspondence between patterns at these two levels would suggest that pre-existing design has a strong influence on evolution, while little or no correspondence shows the action of selection. The variance generated by mutation was equal to that generated by speciation in the family Volvocaceae, the genus Volvox, or the section Merillosphaera, depending on the character considered. We found that mutation changes the volume of somatic tissue independently of the quantity of germ tissue, so that the interspecific correlation between soma and germ can be attributed to selection. The negative correlation between size and number of germ cells among mutants of V. carteri is also seen among the larger members of the family (Volvox spp.), but not among the smaller members, suggesting a powerful design constraint that may be responsible for the absence of larger forms in the entire group.
Collapse
Affiliation(s)
- Vassiliki Koufopanou
- Department of Biology, McGill University, 1205 Avenue Dr. Penfield, Montreal, Quebec, H3A 1B1, CANADA
| | - Graham Bell
- Department of Biology, McGill University, 1205 Avenue Dr. Penfield, Montreal, Quebec, H3A 1B1, CANADA
| |
Collapse
|
18
|
Jiang L, Ni H, Wang QY, Huang L, Zhao SD, Yu JD, Ge RJ. Dual face of axonal inhibitory inputs in the modulation of neuronal excitability in cortical pyramidal neurons. Neural Regen Res 2017; 12:1079-1085. [PMID: 28852389 PMCID: PMC5558486 DOI: 10.4103/1673-5374.211186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Limited by the tiny structure of axons, the effects of these axonal hyperpolarizing inputs on neuronal activity have not been directly elucidated. Here, we imitated these processes by simultaneously recording the activities of the somas and proximal axons of cortical pyramidal neurons. We found that spikes and subthreshold potentials propagate between somas and axons with high fidelity. Furthermore, inhibitory inputs on axons have opposite effects on neuronal activity according to their temporal integration with upstream signals. Concurrent with somatic depolarization, inhibitory inputs on axons decrease neuronal excitability and impede spike generation. In addition, following action potentials, inhibitory inputs on an axon increase neuronal spike capacity and improve spike precision. These results indicate that inhibitory inputs on proximal axons have dual regulatory functions in neuronal activity (suppression or facilitation) according to neuronal network patterns.
Collapse
Affiliation(s)
- Lei Jiang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China.,Department of General Surgery, The Second Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui Province, China
| | - Hong Ni
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Qi-Yi Wang
- Department of Physiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Li Huang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Shi-di Zhao
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Jian-Dong Yu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Joint International Research Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Rong-Jing Ge
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| |
Collapse
|
19
|
Abstract
Soma (Carisoprodol) is N-isopropyl-2 methyl-2-propyl-1,3-propanediol dicarbamate; a commonly prescribed, centrally acting skeletal muscle relaxant. Neuroleptic malignant syndrome (NMS) is a potentially life-threatening adverse effect of antipsychotic agents. Although diagnostic criteria for NMS have been established, it should be recognized that atypical presentations occur and more flexible diagnostic criteria than currently mandated, may be warranted. We wish to report a postoperative case of bilateral knee replacement who presented with carisoprodol (Soma) withdrawal resembling NMS that was a diagnostic dilemma. Subsequently, it was successfully treated with oral baclofen in absence of sodium dantrolene.
Collapse
Affiliation(s)
- Gunchan Paul
- Department of Critical Care Medicine, Dayanand Medical College, Ludhiana, Punjab, India
| | - Gautam L Parshotam
- Department of Critical Care Medicine, Dayanand Medical College, Ludhiana, Punjab, India
| | - Rajneesh Garg
- Department of Orthopedics, Dayanand Medical College, Ludhiana, Punjab, India
| |
Collapse
|
20
|
Abstract
UNLABELLED Autophagy is an essential degradative pathway that maintains neuronal homeostasis and prevents axon degeneration. Initial observations suggest that autophagy is spatially regulated in neurons, but how autophagy is regulated in distinct neuronal compartments is unclear. Using live-cell imaging in mouse hippocampal neurons, we establish the compartment-specific mechanisms of constitutive autophagy under basal conditions, as well as in response to stress induced by nutrient deprivation. We find that at steady state, the cell soma contains populations of autophagosomes derived from distinct neuronal compartments and defined by differences in maturation state and dynamics. Axonal autophagosomes enter the soma and remain confined within the somatodendritic domain. This compartmentalization likely facilitates cargo degradation by enabling fusion with proteolytically active lysosomes enriched in the soma. In contrast, autophagosomes generated within the soma are less mobile and tend to cluster. Surprisingly, starvation did not induce autophagy in either the axonal or somatodendritic compartment. While starvation robustly decreased mTORC1 signaling in neurons, this decrease was not sufficient to activate autophagy. Furthermore, pharmacological inhibition of mammalian target of rapamycin with Torin1 also was not sufficient to markedly upregulate neuronal autophagy. These observations suggest that the primary physiological function of autophagy in neurons may not be to mobilize amino acids and other biosynthetic building blocks in response to starvation, in contrast to findings in other cell types. Rather, constitutive autophagy in neurons may function to maintain cellular homeostasis by balancing synthesis and degradation, especially within distal axonal processes far removed from the soma. SIGNIFICANCE STATEMENT Autophagy is an essential homeostatic process in neurons, but neuron-specific mechanisms are poorly understood. Here, we compare autophagosome dynamics within neuronal compartments. Axonal autophagy is a vectorial process that delivers cargo from the distal axon to the soma. The soma, however, contains autophagosomes at different maturation states, including input received from the axon combined with locally generated autophagosomes. Once in the soma, autophagosomes are confined to the somatodendritic domain, facilitating cargo degradation and recycling of biosynthetic building blocks to primary sites of protein synthesis. Neuronal autophagy is not robustly upregulated in response to starvation or mammalian target of rapamycin inhibition, suggesting that constitutive autophagy in neurons maintains homeostasis by playing an integral role in regulating the quality of the neuronal proteome.
Collapse
Affiliation(s)
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104
| |
Collapse
|
21
|
Abstract
Consumption of one or other form of intoxicating substances has been present throughout the history of the world. This article traces such use in the Indian subcontinent, both in North and South India. References to the use of intoxicants are to be found in the Vedas, the Great Epics, and the ancient Tamil literature.
Collapse
Affiliation(s)
- Ottilingam Somasundaram
- Department of Psychiatry, Madras Medical College, Institute of Mental Health, Chennai, Tamil Nadu, India
| | - D Vijaya Raghavan
- Department of Psychiatry, Madras Medical College, Institute of Mental Health, Chennai, Tamil Nadu, India
| | - A G Tejus Murthy
- Department of Psychiatry, Madras Medical College, Institute of Mental Health, Chennai, Tamil Nadu, India
| |
Collapse
|
22
|
Lynn DA, Dalton HM, Sowa JN, Wang MC, Soukas AA, Curran SP. Omega-3 and -6 fatty acids allocate somatic and germline lipids to ensure fitness during nutrient and oxidative stress in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2015; 112:15378-83. [PMID: 26621724 PMCID: PMC4687584 DOI: 10.1073/pnas.1514012112] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Animals in nature are continually challenged by periods of feast and famine as resources inevitably fluctuate, and must allocate somatic reserves for reproduction to abate evolutionary pressures. We identify an age-dependent lipid homeostasis pathway in Caenorhabditis elegans that regulates the mobilization of lipids from the soma to the germline, which supports fecundity but at the cost of survival in nutrient-poor and oxidative stress environments. This trade-off is responsive to the levels of dietary carbohydrates and organismal oleic acid and is coupled to activation of the cytoprotective transcription factor SKN-1 in both laboratory-derived and natural isolates of C. elegans. The homeostatic balance of lipid stores between the somatic and germ cells is mediated by arachidonic acid (omega-6) and eicosapentaenoic acid (omega-3) precursors of eicosanoid signaling molecules. Our results describe a mechanism for resource reallocation within intact animals that influences reproductive fitness at the cost of somatic resilience.
Collapse
Affiliation(s)
- Dana A Lynn
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Hans M Dalton
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Jessica N Sowa
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Meng C Wang
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Alexander A Soukas
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Sean P Curran
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089;
| |
Collapse
|
23
|
Iwamoto M, Hiraoka Y, Haraguchi T. The nuclear pore complex acts as a master switch for nuclear and cell differentiation. Commun Integr Biol 2015; 8:e1056950. [PMID: 26479399 PMCID: PMC4594561 DOI: 10.1080/19420889.2015.1056950] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 05/20/2015] [Accepted: 05/20/2015] [Indexed: 01/13/2023] Open
Abstract
Cell differentiation is associated with the functional differentiation of the nucleus, in which alteration of the expression profiles of transcription factors occurs to destine cell fate. Nuclear transport machineries, such as importin-α, have also been reported as critical factors that induce cell differentiation. Using various fluorescence live cell imaging methods, including time-lapse imaging, FRAP analysis and live-cell imaging associated correlative light and electron microscopy (Live CLEM) of Tetrahymena, a unicellular ciliated protozoan, we have recently discovered that type switching of the NPC is the earliest detectable event of nuclear differentiation. Our studies suggest that this type switching of the NPC directs the fate of the nucleus to differentiate into either a macronucleus or a micronucleus. Our findings in this organism may provide new insights into the role of the NPC in controlling nuclear functions in general in eukaryotes, including controlling cell fate leading to cell differentiation in multicellular metazoa.
Collapse
Affiliation(s)
- Masaaki Iwamoto
- Advanced ICT Research Institute Kobe; National Institute of Information and Communications Technology (NICT) ; Kobe, Japan
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe; National Institute of Information and Communications Technology (NICT) ; Kobe, Japan ; Graduate School of Frontier Biosciences; Osaka University; Suita, Japan ; Graduate School of Science; Osaka University ; Toyonaka, Japan
| | - Tokuko Haraguchi
- Advanced ICT Research Institute Kobe; National Institute of Information and Communications Technology (NICT) ; Kobe, Japan ; Graduate School of Frontier Biosciences; Osaka University; Suita, Japan ; Graduate School of Science; Osaka University ; Toyonaka, Japan
| |
Collapse
|
24
|
Abstract
This article offers an entirely new way of addressing middle age or mid-life. It uses the neologism maturescence to denote this process's metapsychological feature, and it proposes a meta-psychology of maturescence in order to allow a 'direct understanding of maturescence' instead of the 'indirect understanding of maturescence', which psychoanalytic literature generally alludes to. The paper examines somatic processes specific to male and female climacterics and is focused on to the tension between the soma and the body. It examines the drive increase that Freud posed in climacterics and the somatic climacteric imbalance that begets specific drive activity demanding psychic work, with very different pathways depending on the individual's specific working-through activity. It discusses what happens to the individual when he/she is no longer able to procreate and begins to age; why this process is equivalent for individuals who had children and for others who could not or did not. This somatic event provides a universal constant from which it is possible to understand any individual variable.
Collapse
|