1
|
Zhang Y, Chen Y, Zhuang C, Qi J, Zhao RC, Wang J. Lipid droplets in the nervous system: involvement in cell metabolic homeostasis. Neural Regen Res 2025; 20:740-750. [PMID: 38886939 DOI: 10.4103/nrr.nrr-d-23-01401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 01/20/2024] [Indexed: 06/20/2024] Open
Abstract
Lipid droplets serve as primary storage organelles for neutral lipids in neurons, glial cells, and other cells in the nervous system. Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic reticulum. Previously, lipid droplets were recognized for their role in maintaining lipid metabolism and energy homeostasis; however, recent research has shown that lipid droplets are highly adaptive organelles with diverse functions in the nervous system. In addition to their role in regulating cell metabolism, lipid droplets play a protective role in various cellular stress responses. Furthermore, lipid droplets exhibit specific functions in neurons and glial cells. Dysregulation of lipid droplet formation leads to cellular dysfunction, metabolic abnormalities, and nervous system diseases. This review aims to provide an overview of the role of lipid droplets in the nervous system, covering topics such as biogenesis, cellular specificity, and functions. Additionally, it will explore the association between lipid droplets and neurodegenerative disorders. Understanding the involvement of lipid droplets in cell metabolic homeostasis related to the nervous system is crucial to determine the underlying causes and in exploring potential therapeutic approaches for these diseases.
Collapse
Affiliation(s)
- Yuchen Zhang
- School of Life Sciences, Shanghai University, Shanghai, China
- School of Medicine, Shanghai University, Shanghai, China
| | - Yiqing Chen
- School of Life Sciences, Shanghai University, Shanghai, China
| | - Cheng Zhuang
- School of Life Sciences, Shanghai University, Shanghai, China
| | - Jingxuan Qi
- School of Life Sciences, Shanghai University, Shanghai, China
| | - Robert Chunhua Zhao
- School of Life Sciences, Shanghai University, Shanghai, China
- Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China
- Center of Excellence in Tissue Engineering, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory of New Drug Development and Clinical Trial of Stem Cell Therapy, Beijing, China
| | - Jiao Wang
- School of Life Sciences, Shanghai University, Shanghai, China
| |
Collapse
|
2
|
Clayworth K, Gilbert M, Auld V. Cell Biology Techniques for Studying Drosophila Peripheral Glial Cells. Cold Spring Harb Protoc 2024; 2024:pdb.top108159. [PMID: 37399179 DOI: 10.1101/pdb.top108159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Glial cells are essential for the proper development and functioning of the peripheral nervous system (PNS). The ability to study the biology of glial cells is therefore critical for our ability to understand PNS biology and address PNS maladies. The genetic and proteomic pathways underlying vertebrate peripheral glial biology are understandably complex, with many layers of redundancy making it sometimes difficult to study certain facets of PNS biology. Fortunately, many aspects of vertebrate peripheral glial biology are conserved with those of the fruit fly, Drosophila melanogaster With simple and powerful genetic tools and fast generation times, Drosophila presents an accessible and versatile model for studying the biology of peripheral glia. We introduce here three techniques for studying the cell biology of peripheral glia of Drosophila third-instar larvae. With fine dissection tools and common laboratory reagents, third-instar larvae can be dissected, with extraneous tissues removed, revealing the central nervous system (CNS) and PNS to be processed using a standard immunolabeling protocol. To improve the resolution of peripheral nerves in the z-plane, we describe a cryosectioning method to achieve 10- to 20-µm thick coronal sections of whole larvae, which can then be immunolabeled using a modified version of standard immunolabeling techniques. Finally, we describe a proximity ligation assay (PLA) for detecting close proximity between two proteins-thus inferring protein interaction-in vivo in third-instar larvae. These methods, further described in our associated protocols, can be used to improve our understanding of Drosophila peripheral glia biology, and thus our understanding of PNS biology.
Collapse
Affiliation(s)
- Katherine Clayworth
- Department of Zoology, Cell and Developmental Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Mary Gilbert
- Department of Zoology, Cell and Developmental Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Vanessa Auld
- Department of Zoology, Cell and Developmental Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| |
Collapse
|
3
|
van der Weijden VA, Stötzel M, Iyer DP, Fauler B, Gralinska E, Shahraz M, Meierhofer D, Vingron M, Rulands S, Alexandrov T, Mielke T, Bulut-Karslioglu A. FOXO1-mediated lipid metabolism maintains mammalian embryos in dormancy. Nat Cell Biol 2024; 26:181-193. [PMID: 38177284 PMCID: PMC10866708 DOI: 10.1038/s41556-023-01325-3] [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: 06/23/2022] [Accepted: 11/29/2023] [Indexed: 01/06/2024]
Abstract
Mammalian developmental timing is adjustable in vivo by preserving pre-implantation embryos in a dormant state called diapause. Inhibition of the growth regulator mTOR (mTORi) pauses mouse development in vitro, yet how embryonic dormancy is maintained is not known. Here we show that mouse embryos in diapause are sustained by using lipids as primary energy source. In vitro, supplementation of embryos with the metabolite L-carnitine balances lipid consumption, puts the embryos in deeper dormancy and boosts embryo longevity. We identify FOXO1 as an essential regulator of the energy balance in dormant embryos and propose, through meta-analyses of dormant cell signatures, that it may be a common regulator of dormancy across adult tissues. Our results lift a constraint on in vitro embryo survival and suggest that lipid metabolism may be a critical metabolic transition relevant for longevity and stem cell function across tissues.
Collapse
Affiliation(s)
- Vera A van der Weijden
- Stem Cell Chromatin Group, Department of Genome Regulation, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Maximilian Stötzel
- Stem Cell Chromatin Group, Department of Genome Regulation, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Institute of Chemistry and Biochemistry, Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Dhanur P Iyer
- Stem Cell Chromatin Group, Department of Genome Regulation, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Institute of Chemistry and Biochemistry, Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Beatrix Fauler
- Microscopy and Cryo-Electron Microscopy Facility, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Elzbieta Gralinska
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Roche Innovation Center Zurich, Schlieren, Switzerland
| | - Mohammed Shahraz
- Structural and Computational Biology, European Molecular Biology Laboratory, Heidelberg, Germany
| | - David Meierhofer
- Mass Spectrometry Facility, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Martin Vingron
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Steffen Rulands
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Theodore Alexandrov
- Structural and Computational Biology, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Thorsten Mielke
- Microscopy and Cryo-Electron Microscopy Facility, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Aydan Bulut-Karslioglu
- Stem Cell Chromatin Group, Department of Genome Regulation, Max Planck Institute for Molecular Genetics, Berlin, Germany.
| |
Collapse
|
4
|
Zhang H, Rui M, Ma Z, Gong S, Zhang S, Zhou Q, Gan C, Gong W, Wang S. Golgi-to-ER retrograde transport prevents premature differentiation of Drosophila type II neuroblasts via Notch-signal-sending daughter cells. iScience 2024; 27:108545. [PMID: 38213621 PMCID: PMC10783626 DOI: 10.1016/j.isci.2023.108545] [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: 06/26/2023] [Revised: 09/18/2023] [Accepted: 11/20/2023] [Indexed: 01/13/2024] Open
Abstract
Stem cells are heterogeneous to generate diverse differentiated cell types required for organogenesis; however, the underlying mechanisms that differently maintain these heterogeneous stem cells are not well understood. In this study, we identify that Golgi-to-endoplasmic reticulum (ER) retrograde transport specifically maintains type II neuroblasts (NBs) through the Notch signaling. We reveal that intermediate neural progenitors (INPs), immediate daughter cells of type II NBs, provide Delta and function as the NB niche. The Delta used by INPs is mainly produced by NBs and asymmetrically distributed to INPs. Blocking retrograde transport leads to a decrease in INP number, which reduces Notch activity and results in the premature differentiation of type II NBs. Furthermore, the reduction of Delta could suppress tumor formation caused by type II NBs. Our results highlight the crosstalk between Golgi-to-ER retrograde transport, Notch signaling, stem cell niche, and fusion as an essential step in maintaining the self-renewal of type II NB lineage.
Collapse
Affiliation(s)
- Huanhuan Zhang
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Menglong Rui
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Zhixin Ma
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Sifan Gong
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Shuliu Zhang
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Qingxia Zhou
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Congfeng Gan
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Wenting Gong
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Su Wang
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226019, China
| |
Collapse
|
5
|
Yadav V, Mishra R, Das P, Arya R. Cut homeodomain transcription factor is a novel regulator of growth and morphogenesis of cortex glia niche around neural cells. Genetics 2024; 226:iyad173. [PMID: 37751321 DOI: 10.1093/genetics/iyad173] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/28/2023] Open
Abstract
Cortex glia in Drosophila central nervous system form a niche around neural cells for necessary signals to establish cross talk with their surroundings. These cells grow and expand their thin processes around neural cell bodies. Although essential for the development and function of the nervous system, how these cells make extensive and intricate connected networks remains largely unknown. In this study, we show that Cut, a homeodomain transcription factor, directly regulates the fate of the cortex glia, impacting neural stem cell (NSC) homeostasis. Focusing on the thoracic ventral nerve cord, we found that Cut is required for the normal growth and development of cortex glia and timely increase in DNA content through endocycle to later divide via acytokinetic mitosis. Knockdown of Cut in cortex glia significantly reduces the growth of cellular processes, the network around NSCs, and their progeny's cell bodies. Conversely, overexpression of Cut induces overall growth of the main processes at the expense of side ones. Whereas the Cut knockdown slows down the timely increase of DNA, the Cut overexpression results in a significant increase in nuclear size and volume and a 3-fold increase in DNA content of cortex glia. Further, we note that constitutively high Cut also interfered with nuclei separation during acytokinetic mitosis. Since the cortex glia form syncytial networks around neural cells, the finding identifies Cut as a novel regulator of glial growth and variant cell cycles to support a functional nervous system.
Collapse
Affiliation(s)
- Vaishali Yadav
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Ramkrishna Mishra
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Papri Das
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Richa Arya
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| |
Collapse
|
6
|
Kefi M, Konstantinos P, Balabanidou V, Sarafoglou C, Tsakireli D, Douris V, Monastirioti M, Maréchal JD, Feyereisen R, Vontas J. Insights into unique features of Drosophila CYP4G enzymes. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 164:104041. [PMID: 38008364 DOI: 10.1016/j.ibmb.2023.104041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 11/12/2023] [Accepted: 11/19/2023] [Indexed: 11/28/2023]
Abstract
The cytochrome P450 enzymes of the CYP4G subfamily are some of the most intriguing insect P450s in terms of structure and function. In Drosophila, CYP4G1 is highly expressed in the oenocytes and is the last enzyme in the biosynthesis of cuticular hydrocarbons, while CYP4G15 is expressed in the brain and is of unknown function. Both proteins have a CYP4G-specific and characteristic amino acid sequence insertion corresponding to a loop between the G and H helices whose function is unclear. Here we address these enigmatic structural and functional features of Drosophila CYP4Gs. First, we used reverse genetics to generate D. melanogaster strains in which all or part of the CYP4G-specific loop was removed from CYP4G1. We showed that the full loop was not needed for proper folding of the P450, but it is essential for function, and that just a short stretch of six amino acids is required for the enzyme's ability to make hydrocarbons. Second, we confirmed by immunocytochemistry that CYP4G15 is expressed in the brain and showed that it is specifically associated with the cortex glia cell subtype. We then expressed CYP4G15 ectopically in oenocytes, revealing that it can produce of a blend of hydrocarbons, albeit to quantitatively lower levels resulting in only a partial rescue of CYP4G1 knockdown flies. The CYP4G1 structural variants studied here should facilitate the biochemical characterization of CYP4G enzymes. Our results also raise the question of the putative role of hydrocarbons and their synthesis by cortex glial cells.
Collapse
Affiliation(s)
- Mary Kefi
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Parasyris Konstantinos
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Vasileia Balabanidou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Chara Sarafoglou
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Dimitra Tsakireli
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece; Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Greece
| | - Vassilis Douris
- Department of Biological Applications and Technology, University of Ioannina, 45110, Ioannina, Greece; Biomedical Research Institute (BRI), Foundation for Research and Technology (FORTH), University Campus, 451 10, Ioannina, Greece
| | - Maria Monastirioti
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Jean-Didier Maréchal
- Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., Cerdanyola del Vallès, 08193, Barcelona, Spain
| | - René Feyereisen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Belgium.
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece; Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Greece.
| |
Collapse
|
7
|
Valamparamban GF, Spéder P. Homemade: building the structure of the neurogenic niche. Front Cell Dev Biol 2023; 11:1275963. [PMID: 38107074 PMCID: PMC10722289 DOI: 10.3389/fcell.2023.1275963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/16/2023] [Indexed: 12/19/2023] Open
Abstract
Neural stem/progenitor cells live in an intricate cellular environment, the neurogenic niche, which supports their function and enables neurogenesis. The niche is made of a diversity of cell types, including neurons, glia and the vasculature, which are able to signal to and are structurally organised around neural stem/progenitor cells. While the focus has been on how individual cell types signal to and influence the behaviour of neural stem/progenitor cells, very little is actually known on how the niche is assembled during development from multiple cellular origins, and on the role of the resulting topology on these cells. This review proposes to draw a state-of-the art picture of this emerging field of research, with the aim to expose our knowledge on niche architecture and formation from different animal models (mouse, zebrafish and fruit fly). We will span its multiple aspects, from the existence and importance of local, adhesive interactions to the potential emergence of larger-scale topological properties through the careful assembly of diverse cellular and acellular components.
Collapse
Affiliation(s)
| | - Pauline Spéder
- Institut Pasteur, Université Paris Cité, CNRS UMR3738, Structure and Signals in the Neurogenic Niche, Paris, France
| |
Collapse
|
8
|
Nunes RD, Drummond-Barbosa D. A high-sugar diet, but not obesity, reduces female fertility in Drosophila melanogaster. Development 2023; 150:dev201769. [PMID: 37795747 PMCID: PMC10617608 DOI: 10.1242/dev.201769] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023]
Abstract
Obesity is linked to reduced fertility in various species, from Drosophila to humans. Considering that obesity is often induced by changes in diet or eating behavior, it remains unclear whether obesity, diet, or both reduce fertility. Here, we show that Drosophila females on a high-sugar diet become rapidly obese and less fertile as a result of increased death of early germline cysts and vitellogenic egg chambers (or follicles). They also have high glycogen, glucose and trehalose levels and develop insulin resistance in their fat bodies (but not ovaries). By contrast, females with adipocyte-specific knockdown of the anti-obesity genes brummer or adipose are obese but have normal fertility. Remarkably, females on a high-sugar diet supplemented with a separate source of water have mostly normal fertility and glucose levels, despite persistent obesity, high glycogen and trehalose levels, and fat body insulin resistance. These findings demonstrate that a high-sugar diet affects specific processes in oogenesis independently of insulin resistance, that high glucose levels correlate with reduced fertility on a high-sugar diet, and that obesity alone does not impair fertility.
Collapse
Affiliation(s)
- Rodrigo Dutra Nunes
- Department of Genetics, University of Wisconsin – Madison, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53706, USA
| | - Daniela Drummond-Barbosa
- Department of Genetics, University of Wisconsin – Madison, Madison, WI 53706, USA
- Morgridge Institute for Research, Madison, WI 53706, USA
| |
Collapse
|
9
|
Song C, Broadie K. Fragile X mental retardation protein coordinates neuron-to-glia communication for clearance of developmentally transient brain neurons. Proc Natl Acad Sci U S A 2023; 120:e2216887120. [PMID: 36920921 PMCID: PMC10041173 DOI: 10.1073/pnas.2216887120] [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: 10/05/2022] [Accepted: 02/07/2023] [Indexed: 03/16/2023] Open
Abstract
In the developmental remodeling of brain circuits, neurons are removed by glial phagocytosis to optimize adult behavior. Fragile X mental retardation protein (FMRP) regulates neuron-to-glia signaling to drive glial phagocytosis for targeted neuron pruning. We find that FMRP acts in a mothers against decapentaplegic (Mad)-insulin receptor (InR)-protein kinase B (Akt) pathway to regulate pretaporter (Prtp) and amyloid precursor protein-like (APPL) signals directing this glial clearance. Neuronal RNAi of Drosophila fragile X mental retardation 1 (dfmr1) elevates mad transcript levels and increases pMad signaling. Neuronal dfmr1 and mad RNAi both elevate phospho-protein kinase B (pAkt) and delay neuron removal but cause opposite effects on InR expression. Genetically correcting pAkt levels in the mad RNAi background restores normal remodeling. Consistently, neuronal dfmr1 and mad RNAi both decrease Prtp levels, whereas neuronal InR and akt RNAi increase Prtp levels, indicating FMRP works with pMad and insulin signaling to tightly regulate Prtp signaling and thus control glial phagocytosis for correct circuit remodeling. Neuronal dfmr1 and mad and akt RNAi all decrease APPL levels, with the pathway signaling higher glial endolysosome activity for phagocytosis. These findings reveal a FMRP-dependent control pathway for neuron-to-glia communication in neuronal pruning, identifying potential molecular mechanisms for devising fragile X syndrome treatments.
Collapse
Affiliation(s)
- Chunzhu Song
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN37235
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN37235
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN37235
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN37235
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN37235
| |
Collapse
|
10
|
Aging and memory are altered by genetically manipulating lactate dehydrogenase in the neurons or glia of flies. Aging (Albany NY) 2023; 15:947-981. [PMID: 36849157 PMCID: PMC10008500 DOI: 10.18632/aging.204565] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/20/2023] [Indexed: 03/01/2023]
Abstract
The astrocyte-neuron lactate shuttle hypothesis posits that glial-generated lactate is transported to neurons to fuel metabolic processes required for long-term memory. Although studies in vertebrates have revealed that lactate shuttling is important for cognitive function, it is uncertain if this form of metabolic coupling is conserved in invertebrates or is influenced by age. Lactate dehydrogenase (Ldh) is a rate limiting enzyme that interconverts lactate and pyruvate. Here we genetically manipulated expression of Drosophila melanogaster lactate dehydrogenase (dLdh) in neurons or glia to assess the impact of altered lactate metabolism on invertebrate aging and long-term courtship memory at different ages. We also assessed survival, negative geotaxis, brain neutral lipids (the core component of lipid droplets) and brain metabolites. Both upregulation and downregulation of dLdh in neurons resulted in decreased survival and memory impairment with age. Glial downregulation of dLdh expression caused age-related memory impairment without altering survival, while upregulated glial dLdh expression lowered survival without disrupting memory. Both neuronal and glial dLdh upregulation increased neutral lipid accumulation. We provide evidence that altered lactate metabolism with age affects the tricarboxylic acid (TCA) cycle, 2-hydroxyglutarate (2HG), and neutral lipid accumulation. Collectively, our findings indicate that the direct alteration of lactate metabolism in either glia or neurons affects memory and survival but only in an age-dependent manner.
Collapse
|
11
|
Chen K, Yu Y, Zhang Z, Hu B, Liu X, Tan A. The morphogen Hedgehog is essential for proper adult morphogenesis in Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 153:103906. [PMID: 36587810 DOI: 10.1016/j.ibmb.2022.103906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
The well-known morphogen Hedgehog (Hh) is indispensable for embryo patterning and organ development from invertebrates to vertebrates. The role of Hh signaling pathway has been extensively investigated in the model organism Drosophila melanogaster, whereas its biological functions are still poorly understood in non-drosophilid insects. In the current study, we describe comprehensive investigation of Hh biological roles in the model lepidopteran insect Bombyx mori by using both CRISPR/Cas9-mediated gene ablation and Gal4/UAS-mediated ectopic expression. Direct injection of Cas9 protein and Hh-specific sgRNAs into preblastoderm embryos induced complete lethality. In contrast, Hh mutants obtained by the binary transgenic CRISPR/Cas9 system showed no deleterious phenotypes during embryonic and larval stages. However, mutants showed abnormalities from the pupal stage and most of adult body appendages exhibited severe developmental defects. Molecular analysis focused on wing development reveal that Hh signaling, Imd signaling and Wnt signaling pathways were distorted in Hh mutant wings. Ectopic expression by using the binary Gal4/UAS system induce early larval lethality. On contrary, moderate overexpression of Hh by using a unitary transgenic system resulted in severe defects in adult leg and antenna development. Our data directly provide genetic evidence that Hh plays vital roles in imaginal discs development and proper adult morphogenesis in B. mori.
Collapse
Affiliation(s)
- Kai Chen
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China
| | - Ye Yu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China
| | - Zhongjie Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China
| | - Bo Hu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China
| | - Xiaojing Liu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China
| | - Anjiang Tan
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212100, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, The Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, 212100, China.
| |
Collapse
|
12
|
Petridi S, Dubal D, Rikhy R, van den Ameele J. Mitochondrial respiration and dynamics of in vivo neural stem cells. Development 2022; 149:285126. [PMID: 36445292 PMCID: PMC10112913 DOI: 10.1242/dev.200870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Neural stem cells (NSCs) in the developing and adult brain undergo many different transitions, tightly regulated by extrinsic and intrinsic factors. While the role of signalling pathways and transcription factors is well established, recent evidence has also highlighted mitochondria as central players in NSC behaviour and fate decisions. Many aspects of cellular metabolism and mitochondrial biology change during NSC transitions, interact with signalling pathways and affect the activity of chromatin-modifying enzymes. In this Spotlight, we explore recent in vivo findings, primarily from Drosophila and mammalian model systems, about the role that mitochondrial respiration and morphology play in NSC development and function.
Collapse
Affiliation(s)
- Stavroula Petridi
- Department of Clinical Neurosciences and MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Dnyanesh Dubal
- Department of Clinical Neurosciences and MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.,Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune 411008, India
| | - Richa Rikhy
- Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune 411008, India
| | - Jelle van den Ameele
- Department of Clinical Neurosciences and MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| |
Collapse
|
13
|
Rujano MA, Briand D, Ðelić B, Marc J, Spéder P. An interplay between cellular growth and atypical fusion defines morphogenesis of a modular glial niche in Drosophila. Nat Commun 2022; 13:4999. [PMID: 36008397 PMCID: PMC9411534 DOI: 10.1038/s41467-022-32685-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 08/10/2022] [Indexed: 11/16/2022] Open
Abstract
Neural stem cells (NSCs) live in an intricate cellular microenvironment supporting their activity, the niche. Whilst shape and function are inseparable, the morphogenetic aspects of niche development are poorly understood. Here, we use the formation of a glial niche to investigate acquisition of architectural complexity. Cortex glia (CG) in Drosophila regulate neurogenesis and build a reticular structure around NSCs. We first show that individual CG cells grow tremendously to ensheath several NSC lineages, employing elaborate proliferative mechanisms which convert these cells into syncytia rich in cytoplasmic bridges. CG syncytia further undergo homotypic cell-cell fusion, using defined cell surface receptors and actin regulators. Cellular exchange is however dynamic in space and time. This atypical cell fusion remodels cellular borders, restructuring the CG syncytia. Ultimately, combined growth and fusion builds the multi-level architecture of the niche, and creates a modular, spatial partition of the NSC population. Our findings provide insights into how a niche forms and organises while developing intimate contacts with a stem cell population.
Collapse
Affiliation(s)
| | | | - Bojana Ðelić
- Institut Pasteur, CNRS UMR3738, Paris, France
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Cell Division and Neurogenesis, Ecole Normale Supérieure, CNRS, Inserm, PSL Université Paris, Paris, France
| | - Julie Marc
- Institut Pasteur, CNRS UMR3738, Paris, France
| | | |
Collapse
|
14
|
Nguyen PK, Cheng LY. Non-autonomous regulation of neurogenesis by extrinsic cues: a Drosophila perspective. OXFORD OPEN NEUROSCIENCE 2022; 1:kvac004. [PMID: 38596708 PMCID: PMC10913833 DOI: 10.1093/oons/kvac004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 04/11/2024]
Abstract
The formation of a functional circuitry in the central nervous system (CNS) requires the correct number and subtypes of neural cells. In the developing brain, neural stem cells (NSCs) self-renew while giving rise to progenitors that in turn generate differentiated progeny. As such, the size and the diversity of cells that make up the functional CNS depend on the proliferative properties of NSCs. In the fruit fly Drosophila, where the process of neurogenesis has been extensively investigated, extrinsic factors such as the microenvironment of NSCs, nutrients, oxygen levels and systemic signals have been identified as regulators of NSC proliferation. Here, we review decades of work that explores how extrinsic signals non-autonomously regulate key NSC characteristics such as quiescence, proliferation and termination in the fly.
Collapse
Affiliation(s)
- Phuong-Khanh Nguyen
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Victoria 3010, Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria 3010, Australia
- Department of Anatomy and Physiology, The University of Melbourne, Victoria 3010, Australia
| |
Collapse
|
15
|
Islimye E, Girard V, Gould AP. Functions of Stress-Induced Lipid Droplets in the Nervous System. Front Cell Dev Biol 2022; 10:863907. [PMID: 35493070 PMCID: PMC9047859 DOI: 10.3389/fcell.2022.863907] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/22/2022] [Indexed: 12/12/2022] Open
Abstract
Lipid droplets are highly dynamic intracellular organelles that store neutral lipids such as cholesteryl esters and triacylglycerols. They have recently emerged as key stress response components in many different cell types. Lipid droplets in the nervous system are mostly observed in vivo in glia, ependymal cells and microglia. They tend to become more numerous in these cell types and can also form in neurons as a consequence of ageing or stresses involving redox imbalance and lipotoxicity. Abundant lipid droplets are also a characteristic feature of several neurodegenerative diseases. In this minireview, we take a cell-type perspective on recent advances in our understanding of lipid droplet metabolism in glia, neurons and neural stem cells during health and disease. We highlight that a given lipid droplet subfunction, such as triacylglycerol lipolysis, can be physiologically beneficial or harmful to the functions of the nervous system depending upon cellular context. The mechanistic understanding of context-dependent lipid droplet functions in the nervous system is progressing apace, aided by new technologies for probing the lipid droplet proteome and lipidome with single-cell type precision.
Collapse
|
16
|
Dong Q, Zavortink M, Froldi F, Golenkina S, Lam T, Cheng LY. Glial Hedgehog signalling and lipid metabolism regulate neural stem cell proliferation in Drosophila. EMBO Rep 2021; 22:e52130. [PMID: 33751817 DOI: 10.15252/embr.202052130] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 01/07/2023] Open
Abstract
The final size and function of the adult central nervous system (CNS) are determined by neuronal lineages generated by neural stem cells (NSCs) in the developing brain. In Drosophila, NSCs called neuroblasts (NBs) reside within a specialised microenvironment called the glial niche. Here, we explore non-autonomous glial regulation of NB proliferation. We show that lipid droplets (LDs) which reside within the glial niche are closely associated with the signalling molecule Hedgehog (Hh). Under physiological conditions, cortex glial Hh is autonomously required to sustain niche chamber formation. Upon FGF-mediated cortex glial overgrowth, glial Hh non-autonomously activates Hh signalling in the NBs, which in turn disrupts NB cell cycle progression and its ability to produce neurons. Glial Hh's ability to signal to NB is further modulated by lipid storage regulator lipid storage droplet-2 (Lsd-2) and de novo lipogenesis gene fatty acid synthase 1 (Fasn1). Together, our data suggest that glial-derived Hh modified by lipid metabolism mechanisms can affect the neighbouring NB's ability to proliferate and produce neurons.
Collapse
Affiliation(s)
- Qian Dong
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Michael Zavortink
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Francesca Froldi
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Sofya Golenkina
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Tammy Lam
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia
| | - Louise Y Cheng
- Peter MacCallum Cancer Centre, Parkville, Vic., Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Vic., Australia.,The Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Vic., Australia
| |
Collapse
|