1
|
Chen W, Wu J, Yang C, Li S, Liu Z, An Y, Wang X, Cao J, Xu J, Duan Y, Yuan X, Zhang X, Zhou Y, Ip JPK, Fu AKY, Ip NY, Yao Z, Liu K. Lipin1 depletion coordinates neuronal signaling pathways to promote motor and sensory axon regeneration after spinal cord injury. Proc Natl Acad Sci U S A 2024; 121:e2404395121. [PMID: 39292743 DOI: 10.1073/pnas.2404395121] [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: 03/05/2024] [Accepted: 08/05/2024] [Indexed: 09/20/2024] Open
Abstract
Adult central nervous system (CNS) neurons down-regulate growth programs after injury, leading to persistent regeneration failure. Coordinated lipids metabolism is required to synthesize membrane components during axon regeneration. However, lipids also function as cell signaling molecules. Whether lipid signaling contributes to axon regeneration remains unclear. In this study, we showed that lipin1 orchestrates mechanistic target of rapamycin (mTOR) and STAT3 signaling pathways to determine axon regeneration. We established an mTOR-lipin1-phosphatidic acid/lysophosphatidic acid-mTOR loop that acts as a positive feedback inhibitory signaling, contributing to the persistent suppression of CNS axon regeneration following injury. In addition, lipin1 knockdown (KD) enhances corticospinal tract (CST) sprouting after unilateral pyramidotomy and promotes CST regeneration following complete spinal cord injury (SCI). Furthermore, lipin1 KD enhances sensory axon regeneration after SCI. Overall, our research reveals that lipin1 functions as a central regulator to coordinate mTOR and STAT3 signaling pathways in the CNS neurons and highlights the potential of lipin1 as a promising therapeutic target for promoting the regeneration of motor and sensory axons after SCI.
Collapse
Affiliation(s)
- Weitao Chen
- Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China
| | - Junqiang Wu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Chao Yang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China
| | - Suying Li
- State Key Laboratory of Chemical Biology and Drug Discovery, Research Institute for Future Food, Research Centre for Chinese Medicine Innovation, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region, China
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region, China
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation), Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
- Shenzhen Key Laboratory of Food Biological Safety Control, Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
| | - Zhewei Liu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yongyan An
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Xuejie Wang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Jiaming Cao
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jiahui Xu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China
| | - Yangyang Duan
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China
| | - Xue Yuan
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Xin Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yiren Zhou
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jacque Pak Kan Ip
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Amy K Y Fu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China
| | - Nancy Y Ip
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China
| | - Zhongping Yao
- State Key Laboratory of Chemical Biology and Drug Discovery, Research Institute for Future Food, Research Centre for Chinese Medicine Innovation, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region, China
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region, China
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation), Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
- Shenzhen Key Laboratory of Food Biological Safety Control, Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
| | - Kai Liu
- Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, Guangdong 518057, China
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| |
Collapse
|
2
|
Ma X, Xu S, Zhou Y, Zhang Q, Yang H, Wan B, Yang Y, Miao Z, Xu X. Targeting Nr2e3 to Modulate Tet2 Expression: Therapeutic Potential for Depression Treatment. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400726. [PMID: 38881534 PMCID: PMC11336902 DOI: 10.1002/advs.202400726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 06/01/2024] [Indexed: 06/18/2024]
Abstract
Epigenetic mechanisms such as DNA methylation and hydroxymethylation play a significant role in depression. This research has shown that Ten-eleven translocation 2 (Tet2) deficiency prompts depression-like behaviors, but Tet2's transcriptional regulation remains unclear. In the study, bioinformatics is used to identify nuclear receptor subfamily 2 group E member 3 (Nr2e3) as a potential Tet2 regulator. Nr2e3 is found to enhance Tet2's transcriptional activity by binding to its promoter region. Nr2e3 knockdown in mouse hippocampus leads to reduced Tet2 expression, depression-like behaviors, decreased hydroxymethylation of synaptic genes, and downregulation of synaptic proteins like postsynaptic density 95 KDa (PSD95) and N-methy-d-aspartate receptor 1 (NMDAR1). Fewer dendritic spines are also observed. Nr2e3 thus appears to play an antidepressant role under stress. In search of potential treatments, small molecule compounds to increase Nr2e3 expression are screened. Azacyclonal (AZA) is found to enhance the Nr2e3/Tet2 pathway and exhibited antidepressant effects in stressed mice, increasing PSD95 and NMDAR1 expression and dendritic spine density. This study illuminates Tet2's upstream regulatory mechanism, providing a new target for identifying early depression biomarkers and developing treatments.
Collapse
Affiliation(s)
- Xiaohua Ma
- Department of Neurologythe First Affiliated Hospital of Soochow UniversitySuzhou215000China
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
| | - Shiyao Xu
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
| | - Yaohui Zhou
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
| | - Qian Zhang
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
| | - Hao Yang
- Department of Fetologythe First Affiliated Hospital of Soochow UniversitySuzhou215006China
| | - Bo Wan
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
| | - Yong Yang
- Department of Psychiatrythe Affiliated Guangji Hospital of Soochow UniversitySuzhouJiangsu215000China
| | - Zhigang Miao
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
| | - Xingshun Xu
- Department of Neurologythe First Affiliated Hospital of Soochow UniversitySuzhou215000China
- Institute of NeuroscienceSoochow UniversitySuzhou215123China
- Jiangsu Key Laboratory of Neuropsychiatric DiseasesSoochow UniversitySuzhouJiangsu215123China
| |
Collapse
|
3
|
Rahman M, Nguyen TM, Lee GJ, Kim B, Park MK, Lee CH. Unraveling the Role of Ras Homolog Enriched in Brain (Rheb1 and Rheb2): Bridging Neuronal Dynamics and Cancer Pathogenesis through Mechanistic Target of Rapamycin Signaling. Int J Mol Sci 2024; 25:1489. [PMID: 38338768 PMCID: PMC10855792 DOI: 10.3390/ijms25031489] [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: 12/15/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 02/12/2024] Open
Abstract
Ras homolog enriched in brain (Rheb1 and Rheb2), small GTPases, play a crucial role in regulating neuronal activity and have gained attention for their implications in cancer development, particularly in breast cancer. This study delves into the intricate connection between the multifaceted functions of Rheb1 in neurons and cancer, with a specific focus on the mTOR pathway. It aims to elucidate Rheb1's involvement in pivotal cellular processes such as proliferation, apoptosis resistance, migration, invasion, metastasis, and inflammatory responses while acknowledging that Rheb2 has not been extensively studied. Despite the recognized associations, a comprehensive understanding of the intricate interplay between Rheb1 and Rheb2 and their roles in both nerve and cancer remains elusive. This review consolidates current knowledge regarding the impact of Rheb1 on cancer hallmarks and explores the potential of Rheb1 as a therapeutic target in cancer treatment. It emphasizes the necessity for a deeper comprehension of the molecular mechanisms underlying Rheb1-mediated oncogenic processes, underscoring the existing gaps in our understanding. Additionally, the review highlights the exploration of Rheb1 inhibitors as a promising avenue for cancer therapy. By shedding light on the complicated roles between Rheb1/Rheb2 and cancer, this study provides valuable insights to the scientific community. These insights are instrumental in guiding the identification of novel targets and advancing the development of effective therapeutic strategies for treating cancer.
Collapse
Affiliation(s)
- Mostafizur Rahman
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Tuan Minh Nguyen
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Gi Jeong Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Boram Kim
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| | - Mi Kyung Park
- Department of BioHealthcare, Hwasung Medi-Science University, Hwaseong-si 18274, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Republic of Korea; (M.R.); (G.J.L.)
| |
Collapse
|
4
|
Jeong S. Function and regulation of nitric oxide signaling in Drosophila. Mol Cells 2024; 47:100006. [PMID: 38218653 PMCID: PMC10880079 DOI: 10.1016/j.mocell.2023.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 01/15/2024] Open
Abstract
Nitric oxide (NO) serves as an evolutionarily conserved signaling molecule that plays an important role in a wide variety of cellular processes. Extensive studies in Drosophila melanogaster have revealed that NO signaling is required for development, physiology, and stress responses in many different types of cells. In neuronal cells, multiple NO signaling pathways appear to operate in different combinations to regulate learning and memory formation, synaptic transmission, selective synaptic connections, axon degeneration, and axon regrowth. During organ development, elevated NO signaling suppresses cell cycle progression, whereas downregulated NO leads to an increase in larval body size via modulation of hormone signaling. The most striking feature of the Drosophila NO synthase is that various stressors, such as neuropeptides, aberrant proteins, hypoxia, bacterial infection, and mechanical injury, can activate Drosophila NO synthase, initially regulating cellular physiology to enable cells to survive. However, under severe stress or pathophysiological conditions, high levels of NO promote regulated cell death and the development of neurodegenerative diseases. In this review, I highlight and discuss the current understanding of molecular mechanisms by which NO signaling regulates distinct cellular functions and behaviors.
Collapse
Affiliation(s)
- Sangyun Jeong
- Department of Molecular Biology, Department of Bioactive Material Sciences, and Research Center of Bioactive Materials, Jeonbuk National University, Jeonju, Jeollabukdo 54896, Republic of Korea.
| |
Collapse
|
5
|
Jiang J, Zhang L, Zou J, Liu J, Yang J, Jiang Q, Duan P, Jiang B. Phosphorylated S6K1 and 4E-BP1 play different roles in constitutively active Rheb-mediated retinal ganglion cell survival and axon regeneration after optic nerve injury. Neural Regen Res 2023; 18:2526-2534. [PMID: 37282486 PMCID: PMC10360084 DOI: 10.4103/1673-5374.371372] [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: 06/08/2023] Open
Abstract
Ras homolog enriched in brain (Rheb) is a small GTPase that activates mammalian target of rapamycin complex 1 (mTORC1). Previous studies have shown that constitutively active Rheb can enhance the regeneration of sensory axons after spinal cord injury by activating downstream effectors of mTOR. S6K1 and 4E-BP1 are important downstream effectors of mTORC1. In this study, we investigated the role of Rheb/mTOR and its downstream effectors S6K1 and 4E-BP1 in the protection of retinal ganglion cells. We transfected an optic nerve crush mouse model with adeno-associated viral 2-mediated constitutively active Rheb and observed the effects on retinal ganglion cell survival and axon regeneration. We found that overexpression of constitutively active Rheb promoted survival of retinal ganglion cells in the acute (14 days) and chronic (21 and 42 days) stages of injury. We also found that either co-expression of the dominant-negative S6K1 mutant or the constitutively active 4E-BP1 mutant together with constitutively active Rheb markedly inhibited axon regeneration of retinal ganglion cells. This suggests that mTORC1-mediated S6K1 activation and 4E-BP1 inhibition were necessary components for constitutively active Rheb-induced axon regeneration. However, only S6K1 activation, but not 4E-BP1 knockdown, induced axon regeneration when applied alone. Furthermore, S6K1 activation promoted the survival of retinal ganglion cells at 14 days post-injury, whereas 4E-BP1 knockdown unexpectedly slightly decreased the survival of retinal ganglion cells at 14 days post-injury. Overexpression of constitutively active 4E-BP1 increased the survival of retinal ganglion cells at 14 days post-injury. Likewise, co-expressing constitutively active Rheb and constitutively active 4E-BP1 markedly increased the survival of retinal ganglion cells compared with overexpression of constitutively active Rheb alone at 14 days post-injury. These findings indicate that functional 4E-BP1 and S6K1 are neuroprotective and that 4E-BP1 may exert protective effects through a pathway at least partially independent of Rheb/mTOR. Together, our results show that constitutively active Rheb promotes the survival of retinal ganglion cells and axon regeneration through modulating S6K1 and 4E-BP1 activity. Phosphorylated S6K1 and 4E-BP1 promote axon regeneration but play an antagonistic role in the survival of retinal ganglion cells.
Collapse
Affiliation(s)
- Jikuan Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Lusi Zhang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jingling Zou
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jingyuan Liu
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Jia Yang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Qian Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Peiyun Duan
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| | - Bing Jiang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan Province, China
| |
Collapse
|
6
|
Ju L, Glastad KM, Sheng L, Gospocic J, Kingwell CJ, Davidson SM, Kocher SD, Bonasio R, Berger SL. Hormonal gatekeeping via the blood-brain barrier governs caste-specific behavior in ants. Cell 2023; 186:4289-4309.e23. [PMID: 37683635 PMCID: PMC10807403 DOI: 10.1016/j.cell.2023.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 05/10/2023] [Accepted: 08/01/2023] [Indexed: 09/10/2023]
Abstract
Here, we reveal an unanticipated role of the blood-brain barrier (BBB) in regulating complex social behavior in ants. Using scRNA-seq, we find localization in the BBB of a key hormone-degrading enzyme called juvenile hormone esterase (Jhe), and we show that this localization governs the level of juvenile hormone (JH3) entering the brain. Manipulation of the Jhe level reprograms the brain transcriptome between ant castes. Although ant Jhe is retained and functions intracellularly within the BBB, we show that Drosophila Jhe is naturally extracellular. Heterologous expression of ant Jhe into the Drosophila BBB alters behavior in fly to mimic what is seen in ants. Most strikingly, manipulation of Jhe levels in ants reprograms complex behavior between worker castes. Our study thus uncovers a remarkable, potentially conserved role of the BBB serving as a molecular gatekeeper for a neurohormonal pathway that regulates social behavior.
Collapse
Affiliation(s)
- Linyang Ju
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Karl M Glastad
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - Lihong Sheng
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Janko Gospocic
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Urology and Institute of Neuropathology, Medical Center-University of Freiburg, Freiburg, Germany
| | - Callum J Kingwell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Shawn M Davidson
- Lewis-Sigler Institute for Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Sarah D Kocher
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Roberto Bonasio
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Shelley L Berger
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| |
Collapse
|
7
|
Sanal N, Keding L, Gigengack U, Michalke E, Rumpf S. TORC1 regulation of dendrite regrowth after pruning is linked to actin and exocytosis. PLoS Genet 2023; 19:e1010526. [PMID: 37167328 DOI: 10.1371/journal.pgen.1010526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 05/23/2023] [Accepted: 04/14/2023] [Indexed: 05/13/2023] Open
Abstract
Neurite pruning and regrowth are important mechanisms to adapt neural circuits to distinct developmental stages. Neurite regrowth after pruning often depends on differential regulation of growth signaling pathways, but their precise mechanisms of action during regrowth are unclear. Here, we show that the PI3K/TORC1 pathway is required for dendrite regrowth after pruning in Drosophila peripheral neurons during metamorphosis. TORC1 impinges on translation initiation, and our analysis of 5' untranslated regions (UTRs) of remodeling factor mRNAs linked to actin suggests that TOR selectively stimulates the translation of regrowth over pruning factors. Furthermore, we find that dendrite regrowth also requires the GTPase RalA and the exocyst complex as regulators of polarized secretion, and we provide evidence that this pathway is also regulated by TOR. We propose that TORC1 coordinates dendrite regrowth after pruning by coordinately stimulating the translation of regrowth factors involved in cytoskeletal regulation and secretion.
Collapse
Affiliation(s)
- Neeraja Sanal
- Multiscale Imaging Center, University of Münster, Münster, Germany
| | - Lorena Keding
- Multiscale Imaging Center, University of Münster, Münster, Germany
| | - Ulrike Gigengack
- Multiscale Imaging Center, University of Münster, Münster, Germany
| | - Esther Michalke
- Multiscale Imaging Center, University of Münster, Münster, Germany
| | - Sebastian Rumpf
- Multiscale Imaging Center, University of Münster, Münster, Germany
| |
Collapse
|
8
|
Truman JW, Riddiford LM. Drosophila postembryonic nervous system development: a model for the endocrine control of development. Genetics 2023; 223:iyac184. [PMID: 36645270 PMCID: PMC9991519 DOI: 10.1093/genetics/iyac184] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/13/2022] [Indexed: 01/17/2023] Open
Abstract
During postembryonic life, hormones, including ecdysteroids, juvenile hormones, insulin-like peptides, and activin/TGFβ ligands act to transform the larval nervous system into an adult version, which is a fine-grained mosaic of recycled larval neurons and adult-specific neurons. Hormones provide both instructional signals that make cells competent to undergo developmental change and timing cues to evoke these changes across the nervous system. While touching on all the above hormones, our emphasis is on the ecdysteroids, ecdysone and 20-hydroxyecdysone (20E). These are the prime movers of insect molting and metamorphosis and are involved in all phases of nervous system development, including neurogenesis, pruning, arbor outgrowth, and cell death. Ecdysteroids appear as a series of steroid peaks that coordinate the larval molts and the different phases of metamorphosis. Each peak directs a stereotyped cascade of transcription factor expression. The cascade components then direct temporal programs of effector gene expression, but the latter vary markedly according to tissue and life stage. The neurons read the ecdysteroid titer through various isoforms of the ecdysone receptor, a nuclear hormone receptor. For example, at metamorphosis the pruning of larval neurons is mediated through the B isoforms, which have strong activation functions, whereas subsequent outgrowth is mediated through the A isoform through which ecdysteroids play a permissive role to allow local tissue interactions to direct outgrowth. The major circulating ecdysteroid can also change through development. During adult development ecdysone promotes early adult patterning and differentiation while its metabolite, 20E, later evokes terminal adult differentiation.
Collapse
Affiliation(s)
- James W Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| | - Lynn M Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| |
Collapse
|
9
|
Truman JW, Price J, Miyares RL, Lee T. Metamorphosis of memory circuits in Drosophila reveals a strategy for evolving a larval brain. eLife 2023; 12:80594. [PMID: 36695420 PMCID: PMC9984194 DOI: 10.7554/elife.80594] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 01/24/2023] [Indexed: 01/26/2023] Open
Abstract
Mushroom bodies (MB) of adult Drosophila have a core of thousands of Kenyon neurons; axons of the early-born g class form a medial lobe and those from later-born α'β' and αβ classes form both medial and vertical lobes. The larva, however, hatches with only γ neurons and forms a vertical lobe 'facsimile' using larval-specific axon branches from its γ neurons. MB input (MBINs) and output (MBONs) neurons divide the Kenyon neuron lobes into discrete computational compartments. The larva has 10 such compartments while the adult has 16. We determined the fates of 28 of the 32 MBONs and MBINs that define the 10 larval compartments. Seven compartments are subsequently incorporated into the adult MB; four of their MBINs die, while 12 MBINs/MBONs remodel to function in adult compartments. The remaining three compartments are larval specific. At metamorphosis their MBIN/MBONs trans-differentiate, leaving the MB for other adult brain circuits. The adult vertical lobes are made de novo using MBONs/MBINs recruited from pools of adult-specific neurons. The combination of cell death, compartment shifting, trans-differentiation, and recruitment of new neurons result in no larval MBIN-MBON connections being maintained through metamorphosis. At this simple level, then, we find no anatomical substrate for a memory trace persisting from larva to adult. The adult phenotype of the trans-differentiating neurons represents their evolutionarily ancestral phenotype while their larval phenotype is a derived adaptation for the larval stage. These cells arise primarily within lineages that also produce permanent MBINs and MBONs, suggesting that larval specifying factors may allow information related to birth-order or sibling identity to be interpreted in a modified manner in the larva to allow these neurons to acquire larval phenotypic modifications. The loss of such factors at metamorphosis then allows these neurons to revert to their ancestral functions in the adult.
Collapse
Affiliation(s)
- James W Truman
- Janelia Research CampusAshburnUnited States
- Department of Biology, Friday Harbor Laboratories, University of WashingtonFriday HarborUnited States
| | | | | | - Tzumin Lee
- Janelia Research CampusAshburnUnited States
- Life Sciences Institute, University of MichiganAnn ArborUnited States
| |
Collapse
|
10
|
Lin S. The making of the Drosophila mushroom body. Front Physiol 2023; 14:1091248. [PMID: 36711013 PMCID: PMC9880076 DOI: 10.3389/fphys.2023.1091248] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/02/2023] [Indexed: 01/14/2023] Open
Abstract
The mushroom body (MB) is a computational center in the Drosophila brain. The intricate neural circuits of the mushroom body enable it to store associative memories and process sensory and internal state information. The mushroom body is composed of diverse types of neurons that are precisely assembled during development. Tremendous efforts have been made to unravel the molecular and cellular mechanisms that build the mushroom body. However, we are still at the beginning of this challenging quest, with many key aspects of mushroom body assembly remaining unexplored. In this review, I provide an in-depth overview of our current understanding of mushroom body development and pertinent knowledge gaps.
Collapse
|
11
|
Bornstein B, Meltzer H, Adler R, Alyagor I, Berkun V, Cummings G, Reh F, Keren‐Shaul H, David E, Riemensperger T, Schuldiner O. Transneuronal Dpr12/DIP-δ interactions facilitate compartmentalized dopaminergic innervation of Drosophila mushroom body axons. EMBO J 2021; 40:e105763. [PMID: 33847376 PMCID: PMC8204868 DOI: 10.15252/embj.2020105763] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 02/11/2021] [Accepted: 02/19/2021] [Indexed: 12/31/2022] Open
Abstract
The mechanisms controlling wiring of neuronal networks are not completely understood. The stereotypic architecture of the Drosophila mushroom body (MB) offers a unique system to study circuit assembly. The adult medial MB γ-lobe is comprised of a long bundle of axons that wire with specific modulatory and output neurons in a tiled manner, defining five distinct zones. We found that the immunoglobulin superfamily protein Dpr12 is cell-autonomously required in γ-neurons for their developmental regrowth into the distal γ4/5 zones, where both Dpr12 and its interacting protein, DIP-δ, are enriched. DIP-δ functions in a subset of dopaminergic neurons that wire with γ-neurons within the γ4/5 zone. During metamorphosis, these dopaminergic projections arrive to the γ4/5 zone prior to γ-axons, suggesting that γ-axons extend through a prepatterned region. Thus, Dpr12/DIP-δ transneuronal interaction is required for γ4/5 zone formation. Our study sheds light onto molecular and cellular mechanisms underlying circuit formation within subcellular resolution.
Collapse
Affiliation(s)
- Bavat Bornstein
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Hagar Meltzer
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Ruth Adler
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Idan Alyagor
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Victoria Berkun
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Gideon Cummings
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Fabienne Reh
- Institute of ZoologyUniversity of CologneKölnGermany
| | - Hadas Keren‐Shaul
- Department of ImmunologyWeizmann Institute of ScienceRehovotIsrael
- Life Science Core FacilityWeizmann Institute of ScienceRehovotIsrael
| | - Eyal David
- Department of ImmunologyWeizmann Institute of ScienceRehovotIsrael
| | | | - Oren Schuldiner
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| |
Collapse
|
12
|
Yaniv SP, Meltzer H, Alyagor I, Schuldiner O. Developmental axon regrowth and primary neuron sprouting utilize distinct actin elongation factors. J Cell Biol 2021; 219:151569. [PMID: 32191286 PMCID: PMC7199854 DOI: 10.1083/jcb.201903181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 11/06/2019] [Accepted: 02/14/2020] [Indexed: 01/23/2023] Open
Abstract
Intrinsic neurite growth potential is a key determinant of neuronal regeneration efficiency following injury. The stereotypical remodeling of Drosophila γ-neurons includes developmental regrowth of pruned axons to form adult specific connections, thereby offering a unique system to uncover growth potential regulators. Motivated by the dynamic expression in remodeling γ-neurons, we focus here on the role of actin elongation factors as potential regulators of developmental axon regrowth. We found that regrowth in vivo requires the actin elongation factors Ena and profilin, but not the formins that are expressed in γ-neurons. In contrast, primary γ-neuron sprouting in vitro requires profilin and the formin DAAM, but not Ena. Furthermore, we demonstrate that DAAM can compensate for the loss of Ena in vivo. Similarly, DAAM mutants express invariably high levels of Ena in vitro. Thus, we show that different linear actin elongation factors function in distinct contexts even within the same cell type and that they can partially compensate for each other.
Collapse
Affiliation(s)
- Shiri P Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| |
Collapse
|
13
|
Enriched conditioning expands the regenerative ability of sensory neurons after spinal cord injury via neuronal intrinsic redox signaling. Nat Commun 2020; 11:6425. [PMID: 33349630 PMCID: PMC7752916 DOI: 10.1038/s41467-020-20179-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022] Open
Abstract
Overcoming the restricted axonal regenerative ability that limits functional repair following a central nervous system injury remains a challenge. Here we report a regenerative paradigm that we call enriched conditioning, which combines environmental enrichment (EE) followed by a conditioning sciatic nerve axotomy that precedes a spinal cord injury (SCI). Enriched conditioning significantly increases the regenerative ability of dorsal root ganglia (DRG) sensory neurons compared to EE or a conditioning injury alone, propelling axon growth well beyond the spinal injury site. Mechanistically, we established that enriched conditioning relies on the unique neuronal intrinsic signaling axis PKC-STAT3-NADPH oxidase 2 (NOX2), enhancing redox signaling as shown by redox proteomics in DRG. Finally, NOX2 conditional deletion or overexpression respectively blocked or phenocopied enriched conditioning-dependent axon regeneration after SCI leading to improved functional recovery. These studies provide a paradigm that drives the regenerative ability of sensory neurons offering a potential redox-dependent regenerative model for mechanistic and therapeutic discoveries. Pre conditioning injury or environmental enrichment have been shown to promote axon regeneration. Here the authors show that environmental enrichment, combined with preconditioning injury promotes regeneration via a redox signalling dependent mechanism.
Collapse
|
14
|
Sudarsanam S, Yaniv S, Meltzer H, Schuldiner O. Cofilin regulates axon growth and branching of Drosophila γ-neurons. J Cell Sci 2020; 133:jcs232595. [PMID: 32152181 PMCID: PMC7197873 DOI: 10.1242/jcs.232595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 02/18/2020] [Indexed: 12/29/2022] Open
Abstract
The mechanisms that control intrinsic axon growth potential, and thus axon regeneration following injury, are not well understood. Developmental axon regrowth of Drosophila mushroom body γ-neurons during neuronal remodeling offers a unique opportunity to study the molecular mechanisms controlling intrinsic growth potential. Motivated by the recently uncovered developmental expression atlas of γ-neurons, we here focus on the role of the actin-severing protein cofilin during axon regrowth. We show that Twinstar (Tsr), the fly cofilin, is a crucial regulator of both axon growth and branching during developmental remodeling of γ-neurons. tsr mutant axons demonstrate growth defects both in vivo and in vitro, and also exhibit actin-rich filopodial-like structures at failed branch points in vivo Our data is inconsistent with Tsr being important for increasing G-actin availability. Furthermore, analysis of microtubule localization suggests that Tsr is required for microtubule infiltration into the axon tips and branch points. Taken together, we show that Tsr promotes axon growth and branching, likely by clearing F-actin to facilitate protrusion of microtubules.
Collapse
Affiliation(s)
- Sriram Sudarsanam
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Shiri Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| |
Collapse
|
15
|
Bolus H, Crocker K, Boekhoff-Falk G, Chtarbanova S. Modeling Neurodegenerative Disorders in Drosophila melanogaster. Int J Mol Sci 2020; 21:E3055. [PMID: 32357532 PMCID: PMC7246467 DOI: 10.3390/ijms21093055] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Drosophila melanogaster provides a powerful genetic model system in which to investigate the molecular mechanisms underlying neurodegenerative diseases. In this review, we discuss recent progress in Drosophila modeling Alzheimer's Disease, Parkinson's Disease, Amyotrophic Lateral Sclerosis (ALS), Huntington's Disease, Ataxia Telangiectasia, and neurodegeneration related to mitochondrial dysfunction or traumatic brain injury. We close by discussing recent progress using Drosophila models of neural regeneration and how these are likely to provide critical insights into future treatments for neurodegenerative disorders.
Collapse
Affiliation(s)
- Harris Bolus
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA;
| | - Kassi Crocker
- Genetics Graduate Training Program, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI 53705, USA;
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI 53705, USA
| | - Grace Boekhoff-Falk
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin–Madison, Madison, WI 53705, USA
| | | |
Collapse
|
16
|
Lund-Ricard Y, Cormier P, Morales J, Boutet A. mTOR Signaling at the Crossroad between Metazoan Regeneration and Human Diseases. Int J Mol Sci 2020; 21:E2718. [PMID: 32295297 PMCID: PMC7216262 DOI: 10.3390/ijms21082718] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 02/06/2023] Open
Abstract
A major challenge in medical research resides in controlling the molecular processes of tissue regeneration, as organ and structure damage are central to several human diseases. A survey of the literature reveals that mTOR (mechanistic/mammalian target of rapamycin) is involved in a wide range of regeneration mechanisms in the animal kingdom. More particularly, cellular processes such as growth, proliferation, and differentiation are controlled by mTOR. In addition, autophagy, stem cell maintenance or the newly described intermediate quiescence state, Galert, imply upstream monitoring by the mTOR pathway. In this review, we report the role of mTOR signaling in reparative regenerations in different tissues and body parts (e.g., axon, skeletal muscle, liver, epithelia, appendages, kidney, and whole-body), and highlight how the mTOR kinase can be viewed as a therapeutic target to boost organ repair. Studies in this area have focused on modulating the mTOR pathway in various animal models to elucidate its contribution to regeneration. The diversity of metazoan species used to identify the implication of this pathway might then serve applied medicine (in better understanding what is required for efficient treatments in human diseases) but also evolutionary biology. Indeed, species-specific differences in mTOR modulation can contain the keys to appreciate why certain regeneration processes have been lost or conserved in the animal kingdom.
Collapse
Affiliation(s)
| | | | | | - Agnès Boutet
- Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, Integrative Biology of Marine Models (LBI2M), UMR 8227, Station Biologique de Roscoff (SBR), 29680 Roscoff, France; (Y.L.-R.); (P.C.); (J.M.)
| |
Collapse
|
17
|
Bielopolski N, Amin H, Apostolopoulou AA, Rozenfeld E, Lerner H, Huetteroth W, Lin AC, Parnas M. Inhibitory muscarinic acetylcholine receptors enhance aversive olfactory learning in adult Drosophila. eLife 2019; 8:48264. [PMID: 31215865 PMCID: PMC6641838 DOI: 10.7554/elife.48264] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 06/18/2019] [Indexed: 11/13/2022] Open
Abstract
Olfactory associative learning in Drosophila is mediated by synaptic plasticity between the Kenyon cells of the mushroom body and their output neurons. Both Kenyon cells and their inputs from projection neurons are cholinergic, yet little is known about the physiological function of muscarinic acetylcholine receptors in learning in adult flies. Here, we show that aversive olfactory learning in adult flies requires type A muscarinic acetylcholine receptors (mAChR-A), particularly in the gamma subtype of Kenyon cells. mAChR-A inhibits odor responses and is localized in Kenyon cell dendrites. Moreover, mAChR-A knockdown impairs the learning-associated depression of odor responses in a mushroom body output neuron. Our results suggest that mAChR-A function in Kenyon cell dendrites is required for synaptic plasticity between Kenyon cells and their output neurons.
Collapse
Affiliation(s)
- Noa Bielopolski
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hoger Amin
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | | | - Eyal Rozenfeld
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hadas Lerner
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Wolf Huetteroth
- Institute for Biology, University of Leipzig, Leipzig, Germany
| | - Andrew C Lin
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Moshe Parnas
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
18
|
Ma J, Xu R, Qi S, Wang F, Ma Y, Zhang H, Xu J, Qin X, Zhang H, Liu C, Li B, Chen J, Yang H, Saijilafu. Regulation of adult mammalian intrinsic axonal regeneration by NF‐κB/STAT3 signaling cascade. J Cell Physiol 2019; 234:22517-22528. [PMID: 31102288 DOI: 10.1002/jcp.28815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/07/2019] [Accepted: 04/11/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Jin‐Jin Ma
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Ren‐Jie Xu
- Department of Orthopaedic Surgery, The First Affiliated Hospital Soochow University Suzhou China
- Department of Orthopaedics Suzhou Municipal Hospital/The Affiliated Hospital of Nanjing Medical University Suzhou Jiangsu China
| | - Shi‐Bin Qi
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Feng Wang
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Yan‐Xia Ma
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Hong‐Cheng Zhang
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Jin‐Hui Xu
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Xu‐Zhen Qin
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Hao‐Nan Zhang
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
| | - Chang‐Mei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology Institute of Zoology, Chinese Academy of Science Beijing China
- Savaid Medical School University of Chinese Academy of Sciences Beijing China
| | - Bin Li
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
- Department of Orthopaedic Surgery, The First Affiliated Hospital Soochow University Suzhou China
| | - Jian‐Quan Chen
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
- Department of Orthopaedic Surgery, The First Affiliated Hospital Soochow University Suzhou China
| | - Hui‐Lin Yang
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
- Department of Orthopaedic Surgery, The First Affiliated Hospital Soochow University Suzhou China
| | - Saijilafu
- Orthopaedic Institute, Medical College Soochow University Suzhou Jiangsu China
- Department of Orthopaedic Surgery, The First Affiliated Hospital Soochow University Suzhou China
| |
Collapse
|
19
|
Meltzer H, Marom E, Alyagor I, Mayseless O, Berkun V, Segal-Gilboa N, Unger T, Luginbuhl D, Schuldiner O. Tissue-specific (ts)CRISPR as an efficient strategy for in vivo screening in Drosophila. Nat Commun 2019; 10:2113. [PMID: 31068592 PMCID: PMC6506539 DOI: 10.1038/s41467-019-10140-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/17/2019] [Indexed: 12/22/2022] Open
Abstract
Gene editing by CRISPR/Cas9 is commonly used to generate germline mutations or perform in vitro screens, but applicability for in vivo screening has so far been limited. Recently, it was shown that in Drosophila, Cas9 expression could be limited to a desired group of cells, allowing tissue-specific mutagenesis. Here, we thoroughly characterize tissue-specific (ts)CRISPR within the complex neuronal system of the Drosophila mushroom body. We report the generation of a library of gRNA-expressing plasmids and fly lines using optimized tools, which provides a valuable resource to the fly community. We demonstrate the application of our library in a large-scale in vivo screen, which reveals insights into developmental neuronal remodeling.
Collapse
Affiliation(s)
- Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Efrat Marom
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oded Mayseless
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Victoria Berkun
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Netta Segal-Gilboa
- Structural Proteomics Unit, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Unger
- Structural Proteomics Unit, Weizmann Institute of Science, Rehovot, Israel
| | - David Luginbuhl
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, USA
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
20
|
Alyagor I, Berkun V, Keren-Shaul H, Marmor-Kollet N, David E, Mayseless O, Issman-Zecharya N, Amit I, Schuldiner O. Combining Developmental and Perturbation-Seq Uncovers Transcriptional Modules Orchestrating Neuronal Remodeling. Dev Cell 2019; 47:38-52.e6. [PMID: 30300589 PMCID: PMC6179959 DOI: 10.1016/j.devcel.2018.09.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 06/26/2018] [Accepted: 09/10/2018] [Indexed: 02/06/2023]
Abstract
Developmental neuronal remodeling is an evolutionarily conserved mechanism required for precise wiring of nervous systems. Despite its fundamental role in neurodevelopment and proposed contribution to various neuropsychiatric disorders, the underlying mechanisms are largely unknown. Here, we uncover the fine temporal transcriptional landscape of Drosophila mushroom body γ neurons undergoing stereotypical remodeling. Our data reveal rapid and dramatic changes in the transcriptional landscape during development. Focusing on DNA binding proteins, we identify eleven that are required for remodeling. Furthermore, we sequence developing γ neurons perturbed for three key transcription factors required for pruning. We describe a hierarchical network featuring positive and negative feedback loops. Superimposing the perturbation-seq on the developmental expression atlas highlights a framework of transcriptional modules that together drive remodeling. Overall, this study provides a broad and detailed molecular insight into the complex regulatory dynamics of developmental remodeling and thus offers a pipeline to dissect developmental processes via RNA profiling.
Collapse
Affiliation(s)
- Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Victoria Berkun
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Hadas Keren-Shaul
- Department of Immunology, Weizmann Institute of Sciences, Rehovot, Israel; Life Science Core Facility, Weizmann Institute of Sciences, Rehovot, Israel
| | - Neta Marmor-Kollet
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Eyal David
- Department of Immunology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Oded Mayseless
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Noa Issman-Zecharya
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Ido Amit
- Department of Immunology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel.
| |
Collapse
|
21
|
Ryu JR, Kim JH, Cho HM, Jo Y, Lee B, Joo S, Chae U, Nam Y, Cho IJ, Sun W. A monitoring system for axonal growth dynamics using micropatterns of permissive and Semaphorin 3F chemorepulsive signals. LAB ON A CHIP 2019; 19:291-305. [PMID: 30539180 DOI: 10.1039/c8lc00845k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neurons reach their correct targets by directional outgrowth of axons, which is mediated by attractive or repulsive cues. Growing axons occasionally cross a field of repulsive cues and stop at intermediate targets on the journey to their final destination. However, it is not well-understood how individual growth cones make decisions, and pass through repulsive territory to reach their permissive target regions. We developed a microcontact printing culture system that could trap individual axonal tips in a permissive dot area surrounded by the repulsive signal, semaphorin 3F (Sema3F). Axons of rat hippocampal neurons on the Sema3F/PLL dot array extended in the checkboard pattern with a significantly slow growth rate. The detailed analysis of the behaviors of axonal growth cones revealed the saccadic dynamics in the dot array system. The trapped axonal tips in the permissive area underwent growth cone enlargement with remarkably spiky filopodia, promoting their escape from the Sema3F constraints with straight extension of axons. This structured axonal growth on the dot pattern was disrupted by increased inter-dot distance, or perturbing intracellular signaling machineries. These data indicate that axons grow against repulsive signals by jumping over the repulsive cues, depending on contact signals and intracellular milieu. Our study suggests that our dot array culture system can be used as a screening system to easily and efficiently evaluate ECM or small molecule inhibitors interfering growth cone dynamics leading to controlling axonal growth.
Collapse
Affiliation(s)
- Jae Ryun Ryu
- Department of Anatomy, Brain Korea 21, Korea University College of Medicine, Anam-Dong, Sungbuk-Gu, Seoul, 136-705, Republic of Korea.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Zhang ZY, Yang J, Fan ZH, Wang DL, Wang YY, Zhang T, Yu LM, Yu CY. Fresh human amniotic membrane effectively promotes the repair of injured common peroneal nerve. Neural Regen Res 2019; 14:2199-2208. [PMID: 31397360 PMCID: PMC6788240 DOI: 10.4103/1673-5374.262596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Suture and autologous nerve transplantation are the primary therapeutic measures for completely severed nerves. However, imbalances in the microenvironment and adhesion of surrounding tissues can affect the quality of nerve regeneration and repair. Previous studies have shown that human amniotic membrane can promote the healing of a variety of tissues. In this study, the right common peroneal nerve underwent a 5-mm transection in rats. Epineural nerve repair was performed using 10/0 non-absorbable surgical suture. The repair site was wrapped with a two-layer amniotic membrane with α-cyanoacrylate rapid medical adhesive after suture. Hindlimb motor function was assessed using footprint analysis. Conduction velocity of the common peroneal nerve was calculated by neural electrical stimulation. The retrograde axoplasmic transport of the common peroneal nerve was observed using fast blue BB salt retrograde fluorescent staining. Hematoxylin-eosin staining was used to detect the pathological changes of the common peroneal nerve sputum. The mRNA expression of axon regeneration-related neurotrophic factors and inhibitors was measured using real-time polymerase chain reaction. The results showed that the amniotic membrane significantly improved the function of the injured nerve; the toe spread function rapidly recovered, the nerve conduction velocity was restored, and the number of fast blue BB salt particles were increased in the spinal cord. The amniotic membrane also increased the recovery rate of the tibialis anterior muscle and improved the tissue structure of the muscle. Meanwhile, mRNA expression of nerve growth factor, growth associated protein-43, collapsin response mediator protein-2, and brain-derived neurotrophic factor recovered to near-normal levels, while Lingo-1 mRNA expression decreased significantly in spinal cord tissues. mRNA expression of glial-derived neurotrophic factor did not change significantly. Changes in mRNA levels were more significant in amniotic-membrane-wrapping-treated rats compared with model and nerve sutured rats. These results demonstrate that fresh amniotic membrane wrapping can promote the functional recovery of sutured common peroneal nerve via regulation of expression levels of neurotrophic factors and inhibitors associated with axonal regeneration. The study was approved by the Committee on Animal Research and Ethics at the Affiliate Hospital of Zunyi Medical University, China (approval No. 112) on December 1, 2017.
Collapse
Affiliation(s)
- Zhong-Yuan Zhang
- Key Laboratory of Cell Engineering in Guizhou Province, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou Province, China
| | - Jin Yang
- Key Laboratory of Cell Engineering in Guizhou Province, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou Province; Department of Thyroid and Breast Surgery, Fifth People's Hospital of Chengdu, Chengdu, Sichuan Province, China
| | - Zhen-Hai Fan
- Key Laboratory of Cell Engineering in Guizhou Province, The Affiliated Hospital of Zunyi Medical University; The Team of Scientific and Technological Innovation Talents on The Basic and Clinical Research of Amniotic Membrane and Bone Marrow Stem Cells in Guizhou Province, Zunyi, Guizhou Province, China
| | - Da-Li Wang
- Department of Burn and Plastic Surgery, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou Province, China
| | - Yu-Ying Wang
- Key Laboratory of Cell Engineering in Guizhou Province, The Affiliated Hospital of Zunyi Medical University; The Team of Scientific and Technological Innovation Talents on The Basic and Clinical Research of Amniotic Membrane and Bone Marrow Stem Cells in Guizhou Province, Zunyi, Guizhou Province, China
| | - Tao Zhang
- Key Laboratory of Cell Engineering in Guizhou Province, The Affiliated Hospital of Zunyi Medical University; The Team of Scientific and Technological Innovation Talents on The Basic and Clinical Research of Amniotic Membrane and Bone Marrow Stem Cells in Guizhou Province, Zunyi, Guizhou Province, China
| | - Li-Mei Yu
- Key Laboratory of Cell Engineering in Guizhou Province, The Affiliated Hospital of Zunyi Medical University; The Team of Scientific and Technological Innovation Talents on The Basic and Clinical Research of Amniotic Membrane and Bone Marrow Stem Cells in Guizhou Province, Zunyi, Guizhou Province, China
| | - Chang-Yin Yu
- Department of Neurology, The Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou Province, China
| |
Collapse
|
23
|
Developmental Coordination during Olfactory Circuit Remodeling in Drosophila. Neuron 2018; 99:1204-1215.e5. [PMID: 30146303 DOI: 10.1016/j.neuron.2018.07.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 06/03/2018] [Accepted: 07/27/2018] [Indexed: 02/03/2023]
Abstract
Developmental neuronal remodeling is crucial for proper wiring of the adult nervous system. While remodeling of individual neuronal populations has been studied, how neuronal circuits remodel-and whether remodeling of synaptic partners is coordinated-is unknown. We found that the Drosophila anterior paired lateral (APL) neuron undergoes stereotypic remodeling during metamorphosis in a similar time frame as the mushroom body (MB) ɣ-neurons, with whom it forms a functional circuit. By simultaneously manipulating both neuronal populations, we found that cell-autonomous inhibition of ɣ-neuron pruning resulted in the inhibition of APL pruning in a process that is mediated, at least in part, by Ca2+-Calmodulin and neuronal activity dependent interaction. Finally, ectopic unpruned MB ɣ axons display ectopic connections with the APL, as well as with other neurons, at the adult, suggesting that inhibiting remodeling of one neuronal type can affect the functional wiring of the entire micro-circuit.
Collapse
|
24
|
Differential Requirement for Translation Initiation Factor Pathways during Ecdysone-Dependent Neuronal Remodeling in Drosophila. Cell Rep 2018; 24:2287-2299.e4. [DOI: 10.1016/j.celrep.2018.07.074] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 06/22/2018] [Accepted: 07/23/2018] [Indexed: 11/23/2022] Open
|
25
|
Koch M, Nicolas M, Zschaetzsch M, de Geest N, Claeys A, Yan J, Morgan MJ, Erfurth ML, Holt M, Schmucker D, Hassan BA. A Fat-Facets-Dscam1-JNK Pathway Enhances Axonal Growth in Development and after Injury. Front Cell Neurosci 2018; 11:416. [PMID: 29472843 PMCID: PMC5809495 DOI: 10.3389/fncel.2017.00416] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/12/2017] [Indexed: 11/13/2022] Open
Abstract
Injury to the adult central nervous systems (CNS) can result in severe long-term disability because damaged CNS connections fail to regenerate after trauma. Identification of regulators that enhance the intrinsic growth capacity of severed axons is a first step to restore function. Here, we conducted a gain-of-function genetic screen in Drosophila to identify strong inducers of axonal growth after injury. We focus on a novel axis the Down Syndrome Cell Adhesion Molecule (Dscam1), the de-ubiquitinating enzyme Fat Facets (Faf)/Usp9x and the Jun N-Terminal Kinase (JNK) pathway transcription factor Kayak (Kay)/Fos. Genetic and biochemical analyses link these genes in a common signaling pathway whereby Faf stabilizes Dscam1 protein levels, by acting on the 3'-UTR of its mRNA, and Dscam1 acts upstream of the growth-promoting JNK signal. The mammalian homolog of Faf, Usp9x/FAM, shares both the regenerative and Dscam1 stabilizing activities, suggesting a conserved mechanism.
Collapse
Affiliation(s)
- Marta Koch
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Maya Nicolas
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Marlen Zschaetzsch
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Natalie de Geest
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Annelies Claeys
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Jiekun Yan
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Matthew J Morgan
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Maria-Luise Erfurth
- Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Neuronal Wiring Lab, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Matthew Holt
- Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Laboratory of Glia Biology, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Dietmar Schmucker
- Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Neuronal Wiring Lab, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Bassem A Hassan
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institut du Cerveau et de la Moelle Epinière, Hôpital Pitié-Salpêtrière, UPMC, Sorbonne Universités, Paris, France
| |
Collapse
|
26
|
Chen D, Dale RK, Lei EP. Shep regulates Drosophila neuronal remodeling by controlling transcription of its chromatin targets. Development 2018; 145:dev.154047. [PMID: 29158441 DOI: 10.1242/dev.154047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 11/07/2017] [Indexed: 11/20/2022]
Abstract
Neuronal remodeling is crucial for formation of the mature nervous system and disruption of this process can lead to neuropsychiatric diseases. Global gene expression changes in neurons during remodeling as well as the factors that regulate these changes remain poorly defined. To elucidate this process, we performed RNA-seq on isolated Drosophila larval and pupal neurons and found upregulated synaptic signaling and downregulated gene expression regulators as a result of normal neuronal metamorphosis. We further tested the role of alan shepard (shep), which encodes an evolutionarily conserved RNA-binding protein required for proper neuronal remodeling. Depletion of shep in neurons prevents the execution of metamorphic gene expression patterns, and shep-regulated genes correspond to Shep chromatin and/or RNA-binding targets. Reduced expression of a Shep-inhibited target gene that we identified, brat, is sufficient to rescue neuronal remodeling defects of shep knockdown flies. Our results reveal direct regulation of transcriptional programs by Shep to regulate neuronal remodeling during metamorphosis.
Collapse
Affiliation(s)
- Dahong Chen
- Nuclear Organization and Gene Expression Section, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ryan K Dale
- Nuclear Organization and Gene Expression Section, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elissa P Lei
- Nuclear Organization and Gene Expression Section, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
27
|
Marchetti G, Tavosanis G. Steroid Hormone Ecdysone Signaling Specifies Mushroom Body Neuron Sequential Fate via Chinmo. Curr Biol 2017; 27:3017-3024.e4. [DOI: 10.1016/j.cub.2017.08.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/20/2017] [Accepted: 08/15/2017] [Indexed: 12/12/2022]
|
28
|
Potheraveedu VN, Schöpel M, Stoll R, Heumann R. Rheb in neuronal degeneration, regeneration, and connectivity. Biol Chem 2017; 398:589-606. [PMID: 28212107 DOI: 10.1515/hsz-2016-0312] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 02/02/2017] [Indexed: 01/31/2023]
Abstract
The small GTPase Rheb was originally detected as an immediate early response protein whose expression was induced by NMDA-dependent synaptic activity in the brain. Rheb's activity is highly regulated by its GTPase activating protein (GAP), the tuberous sclerosis complex protein, which stimulates the conversion from the active, GTP-loaded into the inactive, GDP-loaded conformation. Rheb has been established as an evolutionarily conserved molecular switch protein regulating cellular growth, cell volume, cell cycle, autophagy, and amino acid uptake. The subcellular localization of Rheb and its interacting proteins critically regulate its activity and function. In stem cells, constitutive activation of Rheb enhances differentiation at the expense of self-renewal partially explaining the adverse effects of deregulated Rheb in the mammalian brain. In the context of various cellular stress conditions such as oxidative stress, ER-stress, death factor signaling, and cellular aging, Rheb activation surprisingly enhances rather than prevents cellular degeneration. This review addresses cell type- and cell state-specific function(s) of Rheb and mainly focuses on neurons and their surrounding glial cells. Mechanisms will be discussed in the context of therapy that interferes with Rheb's activity using the antibiotic rapamycin or low molecular weight compounds.
Collapse
Affiliation(s)
- Veena Nambiar Potheraveedu
- Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätstr. 150, D-44780 Bochum
| | - Miriam Schöpel
- Biomolecular NMR, Ruhr University of Bochum, D-44780 Bochum
| | - Raphael Stoll
- Biomolecular NMR, Ruhr University of Bochum, D-44780 Bochum
| | - Rolf Heumann
- Molecular Neurobiochemistry, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Universitätstr. 150, D-44780 Bochum
| |
Collapse
|
29
|
Regulatory Mechanisms of Metamorphic Neuronal Remodeling Revealed Through a Genome-Wide Modifier Screen in Drosophila melanogaster. Genetics 2017; 206:1429-1443. [PMID: 28476867 PMCID: PMC5500141 DOI: 10.1534/genetics.117.200378] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/28/2017] [Indexed: 02/01/2023] Open
Abstract
During development, neuronal remodeling shapes neuronal connections to establish fully mature and functional nervous systems. Our previous studies have shown that the RNA-binding factor alan shepard (shep) is an important regulator of neuronal remodeling during metamorphosis in Drosophila melanogaster, and loss of shep leads to smaller soma size and fewer neurites in a stage-dependent manner. To shed light on the mechanisms by which shep regulates neuronal remodeling, we conducted a genetic modifier screen for suppressors of shep-dependent wing expansion defects and cellular morphological defects in a set of peptidergic neurons, the bursicon neurons, that promote posteclosion wing expansion. Out of 702 screened deficiencies that covered 86% of euchromatic genes, we isolated 24 deficiencies as candidate suppressors, and 12 of them at least partially suppressed morphological defects in shep mutant bursicon neurons. With RNA interference and mutant alleles of individual genes, we identified Daughters against dpp (Dad) and Olig family (Oli) as shep suppressor genes, and both of them restored the adult cellular morphology of shep-depleted bursicon neurons. Dad encodes an inhibitory Smad protein that inhibits bone morphogenetic protein (BMP) signaling, raising the possibility that shep interacted with BMP signaling through antagonism of Dad. By manipulating expression of the BMP receptor tkv, we found that activated BMP signaling was sufficient to rescue loss-of-shep phenotypes. These findings reveal mechanisms of shep regulation during neuronal development, and they highlight a novel genetic shep interaction with the BMP signaling pathway that controls morphogenesis in mature, terminally differentiated neurons during metamorphosis.
Collapse
|
30
|
Oren-Suissa M, Gattegno T, Kravtsov V, Podbilewicz B. Extrinsic Repair of Injured Dendrites as a Paradigm for Regeneration by Fusion in Caenorhabditis elegans. Genetics 2017; 206:215-230. [PMID: 28283540 PMCID: PMC5419471 DOI: 10.1534/genetics.116.196386] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 03/07/2017] [Indexed: 11/18/2022] Open
Abstract
Injury triggers regeneration of axons and dendrites. Research has identified factors required for axonal regeneration outside the CNS, but little is known about regeneration triggered by dendrotomy. Here, we study neuronal plasticity triggered by dendrotomy and determine the fate of complex PVD arbors following laser surgery of dendrites. We find that severed primary dendrites grow toward each other and reconnect via branch fusion. Simultaneously, terminal branches lose self-avoidance and grow toward each other, meeting and fusing at the tips via an AFF-1-mediated process. Ectopic branch growth is identified as a step in the regeneration process required for bypassing the lesion site. Failure of reconnection to the severed dendrites results in degeneration of the distal end of the neuron. We discover pruning of excess branches via EFF-1 that acts to recover the original wild-type arborization pattern in a late stage of the process. In contrast, AFF-1 activity during dendritic auto-fusion is derived from the lateral seam cells and not autonomously from the PVD neuron. We propose a model in which AFF-1-vesicles derived from the epidermal seam cells fuse neuronal dendrites. Thus, EFF-1 and AFF-1 fusion proteins emerge as new players in neuronal arborization and maintenance of arbor connectivity following injury in Caenorhabditis elegans Our results demonstrate that there is a genetically determined multi-step pathway to repair broken dendrites in which EFF-1 and AFF-1 act on different steps of the pathway. EFF-1 is essential for dendritic pruning after injury and extrinsic AFF-1 mediates dendrite fusion to bypass injuries.
Collapse
Affiliation(s)
- Meital Oren-Suissa
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Tamar Gattegno
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Veronika Kravtsov
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| |
Collapse
|
31
|
Bodofsky S, Koitz F, Wightman B. CONSERVED AND EXAPTED FUNCTIONS OF NUCLEAR RECEPTORS IN ANIMAL DEVELOPMENT. NUCLEAR RECEPTOR RESEARCH 2017; 4:101305. [PMID: 29333434 PMCID: PMC5761748 DOI: 10.11131/2017/101305] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The nuclear receptor gene family includes 18 members that are broadly conserved among multiple disparate animal phyla, indicating that they trace their evolutionary origins to the time at which animal life arose. Typical nuclear receptors contain two major domains: a DNA-binding domain and a C-terminal domain that may bind a lipophilic hormone. Many of these nuclear receptors play varied roles in animal development, including coordination of life cycle events and cellular differentiation. The well-studied genetic model systems of Drosophila, C. elegans, and mouse permit an evaluation of the extent to which nuclear receptor function in development is conserved or exapted (repurposed) over animal evolution. While there are some specific examples of conserved functions and pathways, there are many clear examples of exaptation. Overall, the evolutionary theme of exaptation appears to be favored over strict functional conservation. Despite strong conservation of DNA-binding domain sequences and activity, the nuclear receptors prove to be highly-flexible regulators of animal development.
Collapse
Affiliation(s)
- Shari Bodofsky
- Biology Department, Muhlenberg College, 2400 Chew St., Allentown, PA 18104
| | - Francine Koitz
- Biology Department, Muhlenberg College, 2400 Chew St., Allentown, PA 18104
| | - Bruce Wightman
- Biology Department, Muhlenberg College, 2400 Chew St., Allentown, PA 18104
| |
Collapse
|
32
|
Kravtsov V, Oren-Suissa M, Podbilewicz B. AFF-1 fusogen can rejuvenate the regenerative potential of adult dendritic trees via self-fusion. Development 2017; 144:2364-2374. [DOI: 10.1242/dev.150037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/27/2017] [Indexed: 12/20/2022]
Abstract
The aging brain undergoes structural changes, affecting brain homeostasis, neuronal function and consequently cognition. The complex architecture of dendritic arbors poses a challenge to understanding age-dependent morphological alterations, behavioral plasticity and remodeling following brain injury. Here, we use the PVD polymodal neurons of C. elegans as a model to study how aging affects neuronal plasticity. Using confocal live imaging of C. elegans PVD neurons, we demonstrate age-related progressive morphological alterations of intricate dendritic arbors. We show that insulin/IGF-1 receptor mutations (daf-2) fail to inhibit the progressive morphological aging of dendrites and do not prevent the minor decline in response to harsh touch during aging. We uncovered that PVD aging is characterized by a major decline in regenerative potential of dendrites following experimental laser dendrotomy. Furthermore, the remodeling of transected dendritic trees via AFF-1-mediated self-fusion can be restored in old animals by DAF-2 insulin/IGF-1 receptor mutations, and can be differentially reestablished by ectopic expression of AFF-1 fusion protein (fusogen). Thus, AFF-1 fusogen ectopically expressed in the PVD and mutations in DAF-2/IGF-1R, differentially rejuvenate some aspects of dendritic regeneration following injury.
Collapse
Affiliation(s)
- Veronika Kravtsov
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - Meital Oren-Suissa
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| |
Collapse
|
33
|
Brace EJ, DiAntonio A. Models of axon regeneration in Drosophila. Exp Neurol 2017; 287:310-317. [PMID: 26996133 PMCID: PMC5026866 DOI: 10.1016/j.expneurol.2016.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 12/14/2022]
Abstract
Maintaining neuronal connectivity in the face of injury and disease is a major challenge for the nervous system. The great length of axons makes them particularly vulnerable to insult with dire consequences for neuronal function. In the peripheral nervous system there is a program of axonal regeneration that can reestablish connectivity. In the mammalian central nervous system, however, injured axons have little or no capacity to regenerate. The molecular mechanisms that promote axon regeneration have begun to be identified and many of the implicated pathways are evolutionarily conserved. Here we discuss Drosophila models of axonal regrowth, describe insights derived from these studies, and highlight future directions in the use of the fly for dissecting the mechanisms of axonal regeneration.
Collapse
Affiliation(s)
- E J Brace
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA, 63110
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA, 63110.
| |
Collapse
|
34
|
Chisholm AD, Hutter H, Jin Y, Wadsworth WG. The Genetics of Axon Guidance and Axon Regeneration in Caenorhabditis elegans. Genetics 2016; 204:849-882. [PMID: 28114100 PMCID: PMC5105865 DOI: 10.1534/genetics.115.186262] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
The correct wiring of neuronal circuits depends on outgrowth and guidance of neuronal processes during development. In the past two decades, great progress has been made in understanding the molecular basis of axon outgrowth and guidance. Genetic analysis in Caenorhabditis elegans has played a key role in elucidating conserved pathways regulating axon guidance, including Netrin signaling, the slit Slit/Robo pathway, Wnt signaling, and others. Axon guidance factors were first identified by screens for mutations affecting animal behavior, and by direct visual screens for axon guidance defects. Genetic analysis of these pathways has revealed the complex and combinatorial nature of guidance cues, and has delineated how cues guide growth cones via receptor activity and cytoskeletal rearrangement. Several axon guidance pathways also affect directed migrations of non-neuronal cells in C. elegans, with implications for normal and pathological cell migrations in situations such as tumor metastasis. The small number of neurons and highly stereotyped axonal architecture of the C. elegans nervous system allow analysis of axon guidance at the level of single identified axons, and permit in vivo tests of prevailing models of axon guidance. C. elegans axons also have a robust capacity to undergo regenerative regrowth after precise laser injury (axotomy). Although such axon regrowth shares some similarities with developmental axon outgrowth, screens for regrowth mutants have revealed regeneration-specific pathways and factors that were not identified in developmental screens. Several areas remain poorly understood, including how major axon tracts are formed in the embryo, and the function of axon regeneration in the natural environment.
Collapse
Affiliation(s)
| | - Harald Hutter
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, and
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
- Department of Pathology and Laboratory Medicine, Howard Hughes Medical Institute, Chevy Chase, Maryland, and
| | - William G Wadsworth
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| |
Collapse
|
35
|
Yaniv SP, Schuldiner O. A fly's view of neuronal remodeling. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:618-35. [PMID: 27351747 PMCID: PMC5086085 DOI: 10.1002/wdev.241] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/10/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
Abstract
Developmental neuronal remodeling is a crucial step in sculpting the final and mature brain connectivity in both vertebrates and invertebrates. Remodeling includes degenerative events, such as neurite pruning, that may be followed by regeneration to form novel connections during normal development. Drosophila provides an excellent model to study both steps of remodeling since its nervous system undergoes massive and stereotypic remodeling during metamorphosis. Although pruning has been widely studied, our knowledge of the molecular and cellular mechanisms is far from complete. Our understanding of the processes underlying regrowth is even more fragmentary. In this review, we discuss recent progress by focusing on three groups of neurons that undergo stereotypic pruning and regrowth during metamorphosis, the mushroom body γ neurons, the dendritic arborization neurons and the crustacean cardioactive peptide peptidergic neurons. By comparing and contrasting the mechanisms involved in remodeling of these three neuronal types, we highlight the common themes and differences as well as raise key questions for future investigation in the field. WIREs Dev Biol 2016, 5:618–635. doi: 10.1002/wdev.241 For further resources related to this article, please visit the WIREs website
Collapse
Affiliation(s)
- Shiri P Yaniv
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oren Schuldiner
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
36
|
Rabinovich D, Yaniv SP, Alyagor I, Schuldiner O. Nitric Oxide as a Switching Mechanism between Axon Degeneration and Regrowth during Developmental Remodeling. Cell 2016; 164:170-182. [PMID: 26771490 DOI: 10.1016/j.cell.2015.11.047] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/02/2015] [Accepted: 11/13/2015] [Indexed: 12/31/2022]
Abstract
During development, neurons switch among growth states, such as initial axon outgrowth, axon pruning, and regrowth. By studying the stereotypic remodeling of the Drosophila mushroom body (MB), we found that the heme-binding nuclear receptor E75 is dispensable for initial axon outgrowth of MB γ neurons but is required for their developmental regrowth. Genetic experiments and pharmacological manipulations on ex-vivo-cultured brains indicate that neuronally generated nitric oxide (NO) promotes pruning but inhibits regrowth. We found that high NO levels inhibit the physical interaction between the E75 and UNF nuclear receptors, likely accounting for its repression of regrowth. Additionally, NO synthase (NOS) activity is downregulated at the onset of regrowth, at least partially, by short inhibitory NOS isoforms encoded within the NOS locus, indicating how NO production could be developmentally regulated. Taken together, these results suggest that NO signaling provides a switching mechanism between the degenerative and regenerative states of neuronal remodeling.
Collapse
Affiliation(s)
- Dana Rabinovich
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Shiri P Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel.
| |
Collapse
|
37
|
|
38
|
Nichols ALA, Meelkop E, Linton C, Giordano-Santini R, Sullivan RK, Donato A, Nolan C, Hall DH, Xue D, Neumann B, Hilliard MA. The Apoptotic Engulfment Machinery Regulates Axonal Degeneration in C. elegans Neurons. Cell Rep 2016; 14:1673-1683. [PMID: 26876181 PMCID: PMC4821572 DOI: 10.1016/j.celrep.2016.01.050] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 12/23/2015] [Accepted: 01/13/2016] [Indexed: 01/31/2023] Open
Abstract
Axonal degeneration is a characteristic feature of neurodegenerative disease and nerve injury. Here, we characterize axonal degeneration in Caenorhabditis elegans neurons following laser-induced axotomy. We show that this process proceeds independently of the WLD(S) and Nmnat pathway and requires the axonal clearance machinery that includes the conserved transmembrane receptor CED-1/Draper, the adaptor protein CED-6, the guanine nucleotide exchange factor complex Crk/Mbc/dCed-12 (CED-2/CED-5/CED-12), and the small GTPase Rac1 (CED-10). We demonstrate that CED-1 and CED-6 function non-cell autonomously in the surrounding hypodermis, which we show acts as the engulfing tissue for the severed axon. Moreover, we establish a function in this process for CED-7, an ATP-binding cassette (ABC) transporter, and NRF-5, a lipid-binding protein, both associated with release of lipid-vesicles during apoptotic cell clearance. Thus, our results reveal the existence of a WLD(S)/Nmnat-independent axonal degeneration pathway, conservation of the axonal clearance machinery, and a function for CED-7 and NRF-5 in this process.
Collapse
Affiliation(s)
- Annika L A Nichols
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ellen Meelkop
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Casey Linton
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rosina Giordano-Santini
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert K Sullivan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Alessandra Donato
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Cara Nolan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David H Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ding Xue
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Brent Neumann
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Massimo A Hilliard
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
| |
Collapse
|
39
|
Bornstein B, Zahavi EE, Gelley S, Zoosman M, Yaniv SP, Fuchs O, Porat Z, Perlson E, Schuldiner O. Developmental Axon Pruning Requires Destabilization of Cell Adhesion by JNK Signaling. Neuron 2015; 88:926-940. [PMID: 26586184 DOI: 10.1016/j.neuron.2015.10.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 09/19/2015] [Accepted: 10/13/2015] [Indexed: 11/25/2022]
Abstract
Developmental axon pruning is essential for normal brain wiring in vertebrates and invertebrates. How axon pruning occurs in vivo is not well understood. In a mosaic loss-of-function screen, we found that Bsk, the Drosophila JNK, is required for axon pruning of mushroom body γ neurons, but not their dendrites. By combining in vivo genetics, biochemistry, and high-resolution microscopy, we demonstrate that the mechanism by which Bsk is required for pruning is through reducing the membrane levels of the adhesion molecule Fasciclin II (FasII), the NCAM ortholog. Conversely, overexpression of FasII is sufficient to inhibit axon pruning. Finally, we show that overexpressing other cell adhesion molecules, together with weak attenuation of JNK signaling, strongly inhibits pruning. Taken together, we have uncovered a novel and unexpected interaction between the JNK pathway and cell adhesion and found that destabilization of cell adhesion is necessary for efficient pruning.
Collapse
Affiliation(s)
- Bavat Bornstein
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Eitan Erez Zahavi
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Sivan Gelley
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Maayan Zoosman
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Shiri Penina Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Ora Fuchs
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Ziv Porat
- Flow Cytometry Unit, Biological Services Department, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel.
| |
Collapse
|
40
|
Rabinovich D, Mayseless O, Schuldiner O. Long term ex vivo culturing of Drosophila brain as a method to live image pupal brains: insights into the cellular mechanisms of neuronal remodeling. Front Cell Neurosci 2015; 9:327. [PMID: 26379498 PMCID: PMC4547045 DOI: 10.3389/fncel.2015.00327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/07/2015] [Indexed: 01/01/2023] Open
Abstract
Holometabolous insects, including Drosophila melanogaster, undergo complete metamorphosis that includes a pupal stage. During metamorphosis, the Drosophila nervous system undergoes massive remodeling and growth, that include cell death and large-scale axon and synapse elimination as well as neurogenesis, developmental axon regrowth, and formation of new connections. Neuronal remodeling is an essential step in the development of vertebrate and invertebrate nervous systems. Research on the stereotypic remodeling of Drosophila mushroom body (MB) γ neurons has contributed to our knowledge of the molecular mechanisms of remodeling but our knowledge of the cellular mechanisms remain poorly understood. A major hurdle in understanding various dynamic processes that occur during metamorphosis is the lack of time-lapse resolution. The pupal case and opaque fat bodies that enwrap the central nervous system (CNS) make live-imaging of the central brain in-vivo impossible. We have established an ex vivo long-term brain culture system that supports the development and neuronal remodeling of pupal brains. By optimizing culture conditions and dissection protocols, we have observed development in culture at kinetics similar to what occurs in vivo. Using this new method, we have obtained the first time-lapse sequence of MB γ neurons undergoing remodeling in up to a single cell resolution. We found that axon pruning is initiated by blebbing, followed by one-two nicks that seem to initiate a more widely spread axon fragmentation. As such, we have set up some of the tools and methodologies needed for further exploration of the cellular mechanisms of neuronal remodeling, not limited to the MB. The long-term ex vivo brain culture system that we report here could be used to study dynamic aspects of neurodevelopment of any Drosophila neuron.
Collapse
Affiliation(s)
- Dana Rabinovich
- Department of Molecular Cell Biology, Weizmann Institute of Sciences Rehovot, Israel
| | - Oded Mayseless
- Department of Molecular Cell Biology, Weizmann Institute of Sciences Rehovot, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences Rehovot, Israel
| |
Collapse
|
41
|
Abstract
The morphology and the connectivity of neuronal structures formed during early development must be actively maintained as the brain matures. Although impaired axon stability is associated with the progression of various neurological diseases, relatively little is known about the factors controlling this process. We identified Brain tumor (Brat), a conserved member of the TRIM-NHL family of proteins, as a new regulator of axon maintenance in Drosophila CNS. Brat function is dispensable for the initial growth of Mushroom Body axons, but is required for the stabilization of axon bundles. We found that Brat represses the translation of src64B, an upstream regulator of a conserved Rho-dependent pathway previously shown to promote axon retraction. Furthermore, brat phenotypes are phenocopied by src64B overexpression, and partially suppressed by reducing the levels of src64B or components of the Rho pathway, suggesting that brat promotes axon maintenance by downregulating the levels of Src64B. Finally, Brat regulates brain connectivity via its NHL domain, but independently of its previously described partners Nanos, Pumilio, and d4EHP. Thus, our results uncover a novel post-transcriptional regulatory mechanism that controls the maintenance of neuronal architecture by tuning the levels of a conserved rho-dependent signaling pathway.
Collapse
|
42
|
Marmor-Kollet N, Schuldiner O. Contrasting developmental axon regrowth and neurite sprouting of Drosophila mushroom body neurons reveals shared and unique molecular mechanisms. Dev Neurobiol 2015; 76:262-76. [PMID: 26037037 DOI: 10.1002/dneu.22312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/14/2015] [Accepted: 05/28/2015] [Indexed: 11/06/2022]
Abstract
The molecular mechanisms regulating intrinsic axon growth potential during development or following injury remain largely unknown despite their vast importance. Here, we have established a neurite sprouting assay of primary cultured mushroom body (MB) neurons. We used the MARCM technique to both mark and manipulate MB neurons, enabling us to quantify the sprouting abilities of single WT and mutant neurons originating from flies at different developmental stages. Sprouting of dissociated MB neurons was dependent on wnd, the DLK ortholog, a conserved gene that is required for axon regeneration. Next, and as expected, we found that the sprouting ability of adult MB neurons was significantly decreased. In contrast, and to our surprise, we found that pupal-derived neurons exhibit increased sprouting compared with neurons derived from larvae, suggesting the existence of an elevated growth potential state. We then contrasted the molecular requirements of neurite sprouting to developmental axon regrowth of MB ɣ neurons, a process that we have previously shown requires the nuclear receptor UNF acting via the target of rapamycin (TOR) pathway. Strikingly, we found that while TOR was required for neurite sprouting, UNF was not. In contrast, we found that PTEN inhibits sprouting in adult neurons, suggesting that TOR is regulated by the PI3K/PTEN pathway during sprouting and by UNF during developmental regrowth. Interestingly, the PI3K pathway as well as Wnd were not required for developmental regrowth nor for initial axon outgrowth suggesting that axon growth during circuit formation, remodeling, and regeneration share some molecular components but differ in others.
Collapse
Affiliation(s)
- Neta Marmor-Kollet
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, 76100, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, 76100, Israel
| |
Collapse
|
43
|
Issman-Zecharya N, Schuldiner O. The PI3K Class III Complex Promotes Axon Pruning by Downregulating a Ptc-Derived Signal via Endosome-Lysosomal Degradation. Dev Cell 2014; 31:461-73. [DOI: 10.1016/j.devcel.2014.10.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 09/08/2014] [Accepted: 10/22/2014] [Indexed: 01/20/2023]
|
44
|
Schuldiner O, Yaron A. Mechanisms of developmental neurite pruning. Cell Mol Life Sci 2014; 72:101-19. [PMID: 25213356 DOI: 10.1007/s00018-014-1729-6] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 12/19/2022]
Abstract
The precise wiring of the nervous system is a combined outcome of progressive and regressive events during development. Axon guidance and synapse formation intertwined with cell death and neurite pruning sculpt the mature circuitry. It is now well recognized that pruning of dendrites and axons as means to refine neuronal networks, is a wide spread phenomena required for the normal development of vertebrate and invertebrate nervous systems. Here we will review the arising principles of cellular and molecular mechanisms of neurite pruning. We will discuss these principles in light of studies in multiple neuronal systems, and speculate on potential explanations for the emergence of neurite pruning as a mechanism to sculpt the nervous system.
Collapse
Affiliation(s)
- Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, 7610001, Rehovot, Israel,
| | | |
Collapse
|
45
|
Bates KE, Molnar J, Robinow S. The unfulfilled gene and nervous system development in Drosophila. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:217-23. [PMID: 24953188 DOI: 10.1016/j.bbagrm.2014.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/07/2014] [Accepted: 06/10/2014] [Indexed: 11/29/2022]
Abstract
The unfulfilled gene of Drosophila encodes a member of the NR2E subfamily of nuclear receptors. Like related members of the NR2E subfamily, UNFULFILLED is anticipated to function as a dimer, binding to DNA response elements and regulating the expression of target genes. The UNFULFILLED protein may be regulated by ligand-binding and may also be post-transcriptionally modified by sumoylation and phosphorylation. unfulfilled mutants display a range of aberrant phenotypes, problems with eclosion and post-eclosion behaviors, compromised fertility, arrhythmicity, and a lack of all adult mushroom body lobes. The locus of the fertility problem has not been determined. The behavioral arrhythmicity is due to the unfulfilled-dependent disruption of gene expression in a set of pacemaker neurons. The eclosion and the mushroom body lobe phenotypes of unfulfilled mutants are the result of developmental problems associated with failures in axon pathfinding or re-extension. Interest in genes that act downstream of unfulfilled has resulted in the identification of a growing number of unfulfilled interacting loci, providing the first glimpse into the composition of unfulfilled-dependent gene networks. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
Collapse
Affiliation(s)
- Karen E Bates
- Department of Biology, University of Hawaii, Honolulu, HI 96822, USA
| | - Janos Molnar
- Department of Biology, University of Hawaii, Honolulu, HI 96822, USA
| | - Steven Robinow
- Department of Biology, University of Hawaii, Honolulu, HI 96822, USA.
| |
Collapse
|
46
|
Boulanger A, Dura JM. Nuclear receptors and Drosophila neuronal remodeling. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:187-95. [PMID: 24882358 DOI: 10.1016/j.bbagrm.2014.05.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/25/2014] [Accepted: 05/26/2014] [Indexed: 11/30/2022]
Abstract
During the development of both vertebrates and invertebrates, neurons undergo a crucial remodeling process that is necessary for their new function. Neuronal remodeling is composed of two stages: first, axons and dendrites are pruned without the loss of the cell body; later, this process is most commonly followed by a regrowth step. Holometabolous insects like the fruitfly Drosophila exhibit striking differences between their larval and adult stages. These neuronal remodeling processes occur during metamorphosis, the period of transformation from a larva to an adult. All axon and dendrite pruning events ultimately depend on the EcR nuclear receptor. Its ligand, the steroid molting hormone ecdysone, binds to heteromeric receptors comprising the nuclear receptor ECR and USP, and this complex regulates target genes involved in neuronal remodeling. Here we review the nuclear receptor-mediated genetic control of the main neuronal remodeling events described so far in Drosophila. These events consist of neurite degeneration in the mushroom bodies (MBs: the brain memory center) and in the dendritic arborizing sensory neurons, of neurite retraction or small scale elimination in the thoracic ventral neurosecretory cells, in the olfactory circuits and in the neuromuscular junction. MB axon regrowth after pruning and the role of MB neuron remodeling in memory formation are also reviewed. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
Collapse
Affiliation(s)
- Ana Boulanger
- Institute of Human Genetics, UPR 1142, CNRS, 141, rue de la Cardonille, 34396 Montpellier, France.
| | - Jean-Maurice Dura
- Institute of Human Genetics, UPR 1142, CNRS, 141, rue de la Cardonille, 34396 Montpellier, France.
| |
Collapse
|
47
|
Yu F, Schuldiner O. Axon and dendrite pruning in Drosophila. Curr Opin Neurobiol 2014; 27:192-8. [PMID: 24793180 DOI: 10.1016/j.conb.2014.04.005] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 01/05/2023]
Abstract
Pruning, a process by which neurons selectively remove exuberant or unnecessary processes without causing cell death, is crucial for the establishment of mature neural circuits during animal development. Yet relatively little is known about molecular and cellular mechanisms that govern neuronal pruning. Holometabolous insects, such as Drosophila, undergo complete metamorphosis and their larval nervous systems are replaced with adult-specific ones, thus providing attractive models for studying neuronal pruning. Drosophila mushroom body and dendritic arborization neurons have been utilized as two appealing systems to elucidate the underlying mechanisms of axon and dendrite pruning, respectively. In this review we highlight recent developments and discuss some similarities and differences in the mechanisms that regulate these two distinct modes of neuronal pruning in Drosophila.
Collapse
Affiliation(s)
- Fengwei Yu
- Temasek Life Sciences Laboratory and Department of Biological Sciences, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot 7610001, Israel.
| |
Collapse
|
48
|
unfulfilled interacting genes display branch-specific roles in the development of mushroom body axons in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2014; 4:693-706. [PMID: 24558265 PMCID: PMC4577660 DOI: 10.1534/g3.113.009829] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The mushroom body (MB) of Drosophila melanogaster is an organized collection of interneurons that is required for learning and memory. Each of the three subtypes of MB neurons, γ, α´/β´, and α/β, branch at some point during their development, providing an excellent model in which to study the genetic regulation of axon branching. Given the sequential birth order and the unique patterning of MB neurons, it is likely that specific gene cascades are required for the different guidance events that form the characteristic lobes of the MB. The nuclear receptor UNFULFILLED (UNF), a transcription factor, is required for the differentiation of all MB neurons. We have developed and used a classical genetic suppressor screen that takes advantage of the fact that ectopic expression of unf causes lethality to identify candidate genes that act downstream of UNF. We hypothesized that reducing the copy number of unf-interacting genes will suppress the unf-induced lethality. We have identified 19 candidate genes that when mutated suppress the unf-induced lethality. To test whether candidate genes impact MB development, we performed a secondary phenotypic screen in which the morphologies of the MBs in animals heterozygous for unf and a specific candidate gene were analyzed. Medial MB lobes were thin, missing, or misguided dorsally in five double heterozygote combinations (;unf/+;axin/+, unf/+;Fps85D/+, ;unf/+;Tsc1/+, ;unf/+;Rheb/+, ;unf/+;msn/+). Dorsal MB lobes were missing in ;unf/+;DopR2/+ or misprojecting beyond the termination point in ;unf/+;Sytβ double heterozygotes. These data suggest that unf and unf-interacting genes play specific roles in axon development in a branch-specific manner.
Collapse
|
49
|
Abstract
Although neurons execute a cell intrinsic program of axonal growth during development, following the establishment of connections, the developmental growth capacity declines. Besides environmental challenges, this switch largely accounts for the failure of adult central nervous system (CNS) axons to regenerate. Here, we discuss the cell intrinsic control of axon regeneration, including not only the regulation of transcriptional and epigenetic mechanisms, but also the modulation of local protein translation, retrograde and anterograde axonal transport, and microtubule dynamics. We further explore the causes underlying the failure of CNS neurons to mount a vigorous regenerative response, and the paradigms demonstrating the activation of cell intrinsic axon growth programs. Finally, we present potential mechanisms to support axon regeneration, as these may represent future therapeutic approaches to promote recovery following CNS injury and disease.
Collapse
Affiliation(s)
- Fernando M Mar
- Nerve Regeneration Group Instituto de Biologia Molecular e Celular - IBMC University of Porto, Porto, Portugal
| | | | | |
Collapse
|
50
|
Gu T, Zhao T, Hewes RS. Insulin signaling regulates neurite growth during metamorphic neuronal remodeling. Biol Open 2014; 3:81-93. [PMID: 24357229 PMCID: PMC3892163 DOI: 10.1242/bio.20136437] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Although the growth capacity of mature neurons is often limited, some neurons can shift through largely unknown mechanisms from stable maintenance growth to dynamic, organizational growth (e.g. to repair injury, or during development transitions). During insect metamorphosis, many terminally differentiated larval neurons undergo extensive remodeling, involving elimination of larval neurites and outgrowth and elaboration of adult-specific projections. Here, we show in the fruit fly, Drosophila melanogaster (Meigen), that a metamorphosis-specific increase in insulin signaling promotes neuronal growth and axon branching after prolonged stability during the larval stages. FOXO, a negative effector in the insulin signaling pathway, blocked metamorphic growth of peptidergic neurons that secrete the neuropeptides CCAP and bursicon. RNA interference and CCAP/bursicon cell-targeted expression of dominant-negative constructs for other components of the insulin signaling pathway (InR, Pi3K92E, Akt1, S6K) also partially suppressed the growth of the CCAP/bursicon neuron somata and neurite arbor. In contrast, expression of wild-type or constitutively active forms of InR, Pi3K92E, Akt1, Rheb, and TOR, as well as RNA interference for negative regulators of insulin signaling (PTEN, FOXO), stimulated overgrowth. Interestingly, InR displayed little effect on larval CCAP/bursicon neuron growth, in contrast to its strong effects during metamorphosis. Manipulations of insulin signaling in many other peptidergic neurons revealed generalized growth stimulation during metamorphosis, but not during larval development. These findings reveal a fundamental shift in growth control mechanisms when mature, differentiated neurons enter a new phase of organizational growth. Moreover, they highlight strong evolutionarily conservation of insulin signaling in neuronal growth regulation.
Collapse
Affiliation(s)
- Tingting Gu
- Department of Biology, University of Oklahoma, Norman, OK 73019, USA
| | | | | |
Collapse
|