1
|
Hubert A, Farkouh G, Harms F, Veilly C, Imperato S, Mercier M, Loriette V, Rouyer F, Fragola A. Enhanced neuroimaging with a calcium sensor in ex-vivo Drosophila melanogaster brains using closed-loop adaptive optics light-sheet fluorescence microscopy. J Biomed Opt 2023; 28:066501. [PMID: 37334209 PMCID: PMC10275380 DOI: 10.1117/1.jbo.28.6.066501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/20/2023]
Abstract
Significance Adaptive optics (AO) has been implemented on several microscopy setups and has proven its ability to increase both signal and resolution. However, reported configurations are not suited for fast imaging of live samples or are based on an invasive or complex implementation method. Aim Provide a fast aberration correction method with an easy to implement AO module compatible with light-sheet fluorescence microscopy (LSFM) for enhanced imaging of live samples. Approach Development of an AO add-on module for LSFM based on direct wavefront sensing without requiring a guide star using an extended-scene Shack-Hartmann wavefront sensor. The enhanced setup uses a two-color sample labeling strategy to optimize the photon budget. Results Fast AO correction of in-depth aberrations in an ex-vivo adult Drosophila brain enables doubling the contrast when imaging with either cell reporters or calcium sensors for functional imaging. We quantify the gain in terms of image quality on different functional domains of sleep neurons in the Drosophila brain at various depths and discuss the optimization of key parameters driving AO. Conclusion We developed a compact AO module that can be integrated into most of the reported light-sheet microscopy setups, provides significant improvement of image quality and is compatible with fast imaging requirements such as calcium imaging.
Collapse
Affiliation(s)
- Antoine Hubert
- Sorbonne Université, PSL Research University, CNRS, Laboratoire Physique et Etudes des Matériaux, ESPCI Paris, Paris, France
- Imagine Optic, Orsay, France
| | - Georges Farkouh
- Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | | | | | - Sophia Imperato
- Sorbonne Université, PSL Research University, CNRS, Laboratoire Physique et Etudes des Matériaux, ESPCI Paris, Paris, France
| | - Mathias Mercier
- Sorbonne Université, PSL Research University, CNRS, Laboratoire Physique et Etudes des Matériaux, ESPCI Paris, Paris, France
| | - Vincent Loriette
- Sorbonne Université, PSL Research University, CNRS, Laboratoire Physique et Etudes des Matériaux, ESPCI Paris, Paris, France
| | - François Rouyer
- Université Paris Saclay, Institut des Neurosciences Paris-Saclay, CNRS, Saclay, France
| | - Alexandra Fragola
- Université Paris-Saclay, Institut des Sciences Moléculaires d’Orsay, CNRS, Orsay, France
| |
Collapse
|
2
|
Hildebrandt K, Klöppel C, Gogel J, Hartenstein V, Walldorf U. Orthopedia expression during Drosophila melanogaster nervous system development and its regulation by microRNA-252. Dev Biol 2022; 492:87-100. [PMID: 36179878 DOI: 10.1016/j.ydbio.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/05/2022] [Accepted: 09/19/2022] [Indexed: 11/03/2022]
Abstract
During brain development of Drosophila melanogaster many transcription factors are involved in regulating neural fate and morphogenesis. In our study we show that the transcription factor Orthopedia (Otp), a member of the 57B homeobox gene cluster, plays an important role in this process. Otp is expressed in a stable pattern in defined lineages from mid-embryonic stages into the adult brain and therefore a very stable marker for these lineages. We determined the abundance of the two different otp transcripts in the brain and hindgut during development using qPCR. CRISPR/Cas9 generated otp mutants of the longer protein form significantly affect the expression of Otp in specific areas. We generated an otp enhancer trap strain by gene targeting and reintegration of Gal4, which mimics the complete expression of otp during development except the embryonic hindgut expression. Since in the embryo, the expression of Otp is posttranscriptionally regulated, we looked for putative miRNAs interacting with the otp 3'UTR, and identified microRNA-252 as a candidate. Further analyses with mutated and deleted forms of the microRNA-252 interacting sequence in the otp 3'UTR demonstrate an in vivo interaction of microRNA-252 with the otp 3'UTR. An effect of this interaction is seen in the adult brain, where Otp expression is partially abolished in a knockout strain of microRNA-252. Our results show that Otp is another important factor for brain development in Drosophila melanogaster.
Collapse
Affiliation(s)
- Kirsten Hildebrandt
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany
| | - Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany
| | - Jasmin Gogel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA, 90095, USA
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany.
| |
Collapse
|
3
|
Dvořáček J, Kodrík D. Drug effect and addiction research with insects - From Drosophila to collective reward in honeybees. Neurosci Biobehav Rev 2022; 140:104816. [PMID: 35940307 DOI: 10.1016/j.neubiorev.2022.104816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 10/16/2022]
Abstract
Animals and humans share similar reactions to the effects of addictive substances, including those of their brain networks to drugs. Our review focuses on simple invertebrate models, particularly the honeybee (Apis mellifera), and on the effects of drugs on bee behaviour and brain functions. The drug effects in bees are very similar to those described in humans. Furthermore, the honeybee community is a superorganism in which many collective functions outperform the simple sum of individual functions. The distribution of reward functions in this superorganism is unique - although sublimated at the individual level, community reward functions are of higher quality. This phenomenon of collective reward may be extrapolated to other animal species living in close and strictly organised societies, i.e. humans. The relationship between sociality and reward, based on use of similar parts of the neural network (social decision-making network in mammals, mushroom body in bees), suggests a functional continuum of reward and sociality in animals.
Collapse
Affiliation(s)
- Jiří Dvořáček
- Institute of Entomology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05, České Budĕjovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budĕjovice, Czech Republic.
| | - Dalibor Kodrík
- Institute of Entomology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05, České Budĕjovice, Czech Republic; Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budĕjovice, Czech Republic
| |
Collapse
|
4
|
Frey F, Sandakly J, Ghannam M, Doueiry C, Hugosson F, Berlandi J, Ismail JN, Gayden T, Hasselblatt M, Jabado N, Shirinian M. Drosophila Tet Is Required for Maintaining Glial Homeostasis in Developing and Adult Fly Brains. eNeuro 2022; 9:ENEURO. [PMID: 35396259 DOI: 10.1523/ENEURO.0418-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 11/21/2022] Open
Abstract
Ten-eleven translocation (TET) proteins are crucial epigenetic regulators highly conserved in multicellular organisms. TETs’ enzymatic function in demethylating 5-methyl cytosine in DNA is required for proper development and TETs are frequently mutated in cancer. Recently, Drosophila melanogaster Tet (dTet) was shown to be highly expressed in developing fly brains and discovered to play an important role in brain and muscle development as well as fly behavior. Furthermore, dTet was shown to have different substrate specificity compared with mammals. However, the exact role dTet plays in glial cells and how ectopic TET expression in glial cells contributes to tumorigenesis and glioma is still not clear. Here, we report a novel role for dTet specifically in glial cell organization and number. We show that loss of dTet affects the organization of a specific glia population in the optic lobe, the “optic chiasm” glia. Additionally, we find irregularities in axon patterns in the ventral nerve cord (VNC) both, in the midline and longitudinal axons. These morphologic glia and axonal defects were accompanied by locomotor defects in developing larvae escalating to immobility in adult flies. Furthermore, glia homeostasis was disturbed in dTet-deficient brains manifesting in gain of glial cell numbers and increased proliferation. Finally, we establish a Drosophila model to understand the impact of human TET3 in glia and find that ectopic expression of hTET3 in dTet-expressing cells causes glia expansion in larval brains and affects sleep/rest behavior and the circadian clock in adult flies.
Collapse
|
5
|
Li Y, Walker LA, Zhao Y, Edwards EM, Michki NS, Cheng HPJ, Ghazzi M, Chen TY, Chen M, Roossien DH, Cai D. Bitbow Enables Highly Efficient Neuronal Lineage Tracing and Morphology Reconstruction in Single Drosophila Brains. Front Neural Circuits 2021; 15:732183. [PMID: 34744636 PMCID: PMC8564373 DOI: 10.3389/fncir.2021.732183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/14/2021] [Indexed: 12/15/2022] Open
Abstract
Identifying the cellular origins and mapping the dendritic and axonal arbors of neurons have been century old quests to understand the heterogeneity among these brain cells. Current Brainbow based transgenic animals take the advantage of multispectral labeling to differentiate neighboring cells or lineages, however, their applications are limited by the color capacity. To improve the analysis throughput, we designed Bitbow, a digital format of Brainbow which exponentially expands the color palette to provide tens of thousands of spectrally resolved unique labels. We generated transgenic Bitbow Drosophila lines, established statistical tools, and streamlined sample preparation, image processing, and data analysis pipelines to conveniently mapping neural lineages, studying neuronal morphology and revealing neural network patterns with unprecedented speed, scale, and resolution.
Collapse
Affiliation(s)
- Ye Li
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Logan A Walker
- Biophysics LS&A, University of Michigan, Ann Arbor, MI, United States
| | - Yimeng Zhao
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Erica M Edwards
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Nigel S Michki
- Biophysics LS&A, University of Michigan, Ann Arbor, MI, United States
| | - Hon Pong Jimmy Cheng
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Marya Ghazzi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Tiffany Y Chen
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Maggie Chen
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Douglas H Roossien
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Dawen Cai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Biophysics LS&A, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| |
Collapse
|
6
|
Jang HJ, Le MUT, Park JH, Chung CG, Shon JG, Lee GS, Moon JH, Lee SB, Choi JS, Lee TG, Yoon S. Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging of Phospholipid Changes in a Drosophila Model of Early Amyotrophic Lateral Sclerosis. J Am Soc Mass Spectrom 2021; 32:2536-2545. [PMID: 34448582 DOI: 10.1021/jasms.1c00167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a degenerative disease caused by motor neuron damage in the central nervous system, and it is difficult to diagnose early. Drosophila melanogaster is widely used to investigate disease mechanisms and discover biomarkers because it is easy to induce disease in Drosophila through genetic engineering. We performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to investigate changes in phospholipid distribution in the brain tissue of an ALS-induced Drosophila model. Fly brain tissues of several hundred micrometers or less were sampled using a fly collar to obtain reproducible tissue sections of similar sizes. MSI of brain tissues of Drosophila cultured for 1 or 10 days showed that the distribution of phospholipids, including phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA), phosphatidylserine (PS), and phosphatidylinositol (PI), was significantly different between the control group and the ALS group. In addition, the lipid profile according to phospholipids differed as the culture time increased from 1 to 10 days. These results suggest that disease indicators based on lipid metabolites can be discovered by performing MALDI-MSI on very small brain tissue samples from the Drosophila disease model to ultimately assess the phospholipid changes that occur in early-stage ALS.
Collapse
Affiliation(s)
- Hyun Jun Jang
- Bio-imaging Team, Safety Measurement Institute, Korea Research Institute of Standard and Science (KRISS), Daejeon 34113, Republic of Korea
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Minh Uyen Thi Le
- Bio-imaging Team, Safety Measurement Institute, Korea Research Institute of Standard and Science (KRISS), Daejeon 34113, Republic of Korea
- Department of Nano Science, University of Science and Technology (UST), Daejeon 34113, South Korea
| | - Jeong Hyang Park
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Chang Geon Chung
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Jin Gyeong Shon
- Bio-imaging Team, Safety Measurement Institute, Korea Research Institute of Standard and Science (KRISS), Daejeon 34113, Republic of Korea
| | - Ga Seul Lee
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Jeong Hee Moon
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Joon Sig Choi
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Tae Geol Lee
- Bio-imaging Team, Safety Measurement Institute, Korea Research Institute of Standard and Science (KRISS), Daejeon 34113, Republic of Korea
| | - Sohee Yoon
- Bio-imaging Team, Safety Measurement Institute, Korea Research Institute of Standard and Science (KRISS), Daejeon 34113, Republic of Korea
| |
Collapse
|
7
|
Kolb D, Kaspar P, Klöppel C, Walldorf U. The Drosophila homeodomain transcription factor Homeobrain is involved in the formation of the embryonic protocerebrum and the supraesophageal brain commissure. Cells Dev 2021; 165:203657. [PMID: 33993980 DOI: 10.1016/j.cdev.2021.203657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/06/2020] [Accepted: 12/09/2020] [Indexed: 11/28/2022]
Abstract
During the embryonic development of Drosophila melanogaster many transcriptional activators are involved in the formation of the embryonic brain. In our study we show that the transcription factor Homeobrain (Hbn), a member of the 57B homeobox gene cluster, is an additional factor involved in the formation of the embryonic Drosophila brain. Using a Hbn antibody and specific cell type markers a detailed expression analysis during embryonic brain development was conducted. We show that Hbn is expressed in several regions in the protocerebrum, including fibre tract founder cells closely associated with the supraesophageal brain commissure and also in the mushroom bodies. During the formation of the supraesophageal commissure, Hbn and FasII-positive founder cells build an interhemispheric bridge priming the commissure and thereby linking both brain hemispheres. The Hbn expression is restricted to neural but not glial cells in the embryonic brain. In a mutagenesis screen we generated two mutant hbn alleles that both show embryonic lethality. The phenotype of the hbn mutant alleles is characterized by a reduction of the protocerebrum, a loss of the supraesophageal commissure and mushroom body progenitors and also by a dislocation of the optic lobes. Extensive apoptosis correlates with the impaired formation of the embryonic protocerebrum and the supraesophageal commissure. Our results show that Hbn is another important factor for embryonic brain development in Drosophila melanogaster.
Collapse
Affiliation(s)
- Dieter Kolb
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Petra Kaspar
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany.
| |
Collapse
|
8
|
Wolff T, Rubin GM. Neuroarchitecture of the Drosophila central complex: A catalog of nodulus and asymmetrical body neurons and a revision of the protocerebral bridge catalog. J Comp Neurol 2018; 526:2585-2611. [PMID: 30084503 PMCID: PMC6283239 DOI: 10.1002/cne.24512] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 12/17/2022]
Abstract
The central complex, a set of neuropils in the center of the insect brain, plays a crucial role in spatial aspects of sensory integration and motor control. Stereotyped neurons interconnect these neuropils with one another and with accessory structures. We screened over 5,000 Drosophila melanogaster GAL4 lines for expression in two neuropils, the noduli (NO) of the central complex and the asymmetrical body (AB), and used multicolor stochastic labeling to analyze the morphology, polarity, and organization of individual cells in a subset of the GAL4 lines that showed expression in these neuropils. We identified nine NO and three AB cell types and describe them here. The morphology of the NO neurons suggests that they receive input primarily in the lateral accessory lobe and send output to each of the six paired noduli. We demonstrate that the AB is a bilateral structure which exhibits asymmetry in size between the left and right bodies. We show that the AB neurons directly connect the AB to the central complex and accessory neuropils, that they target both the left and right ABs, and that one cell type preferentially innervates the right AB. We propose that the AB be considered a central complex neuropil in Drosophila. Finally, we present highly restricted GAL4 lines for most identified protocerebral bridge, NO, and AB cell types. These lines, generated using the split-GAL4 method, will facilitate anatomical studies, behavioral assays, and physiological experiments.
Collapse
Affiliation(s)
- Tanya Wolff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| |
Collapse
|
9
|
Croset V, Treiber CD, Waddell S. Cellular diversity in the Drosophila midbrain revealed by single-cell transcriptomics. eLife 2018; 7:34550. [PMID: 29671739 PMCID: PMC5927767 DOI: 10.7554/elife.34550] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/18/2018] [Indexed: 12/12/2022] Open
Abstract
To understand the brain, molecular details need to be overlaid onto neural wiring diagrams so that synaptic mode, neuromodulation and critical signaling operations can be considered. Single-cell transcriptomics provide a unique opportunity to collect this information. Here we present an initial analysis of thousands of individual cells from Drosophila midbrain, that were acquired using Drop-Seq. A number of approaches permitted the assignment of transcriptional profiles to several major brain regions and cell-types. Expression of biosynthetic enzymes and reuptake mechanisms allows all the neurons to be typed according to the neurotransmitter or neuromodulator that they produce and presumably release. Some neuropeptides are preferentially co-expressed in neurons using a particular fast-acting transmitter, or monoamine. Neuromodulatory and neurotransmitter receptor subunit expression illustrates the potential of these molecules in generating complexity in neural circuit function. This cell atlas dataset provides an important resource to link molecular operations to brain regions and complex neural processes.
Collapse
Affiliation(s)
- Vincent Croset
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
| | - Christoph D Treiber
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, The University of Oxford, Oxford, United Kingdom
| |
Collapse
|
10
|
Cabirol-Pol MJ, Khalil B, Rival T, Faivre-Sarrailh C, Besson MT. Glial lipid droplets and neurodegeneration in a Drosophila model of complex I deficiency. Glia 2017; 66:874-888. [PMID: 29285794 DOI: 10.1002/glia.23290] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 01/09/2023]
Abstract
Mitochondrial defects associated with respiratory chain complex I deficiency lead to heterogeneous fatal syndromes. While the role of NDUFS8, an essential subunit of the core assembly of the complex I, is established in mitochondrial diseases, the mechanisms underlying neuropathology are poorly understood. We developed a Drosophila model of NDUFS8 deficiency by knocking down the expression of its fly homologue in neurons or in glial cells. Downregulating ND23 in neurons resulted in shortened lifespan, and decreased locomotion. Although total brain ATP levels were decreased, histological analysis did not reveal any signs of neurodegeneration except for photoreceptors of the retina. Interestingly, ND23 deficiency-associated phenotypes were rescued by overexpressing the glucose transporter hGluT3 demonstrating that boosting glucose metabolism in neurons was sufficient to bypass altered mitochondrial functions and to confer neuroprotection. We then analyzed the consequences of ND23 knockdown in glial cells. In contrast to neuronal knockdown, loss of ND23 in glia did not lead to significant behavioral defects nor to reduced lifespan, but induced brain degeneration, as visualized by numerous vacuoles found all over the nervous tissue. This phenotype was accompanied by the massive accumulation of lipid droplets at the cortex-neuropile boundaries, suggesting an alteration of lipid metabolism in glia. These results demonstrate that complex I deficiency triggers metabolic alterations both in neurons and glial cells which may contribute to the neuropathology.
Collapse
Affiliation(s)
| | - Bilal Khalil
- Aix Marseille Université, CNRS, CRN2M-UMR7286, 13344 Marseille cedex 15, Marseille, France.,Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida
| | - Thomas Rival
- Aix Marseille Université, CNRS, IBDM UMR 7288, Marseille, France
| | | | - Marie Thérèse Besson
- Aix Marseille Université, CNRS, CRN2M-UMR7286, 13344 Marseille cedex 15, Marseille, France
| |
Collapse
|
11
|
Janssens DH, Hamm DC, Anhezini L, Xiao Q, Siller KH, Siegrist SE, Harrison MM, Lee CY. An Hdac1/Rpd3-Poised Circuit Balances Continual Self-Renewal and Rapid Restriction of Developmental Potential during Asymmetric Stem Cell Division. Dev Cell 2017; 40:367-380.e7. [PMID: 28245922 DOI: 10.1016/j.devcel.2017.01.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 12/16/2016] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
Abstract
How the developmental potential of differentiating stem cell progeny becomes rapidly and stably restricted following asymmetric stem cell division is unclear. In the fly larval brain, earmuff (erm) uniquely functions to restrict the developmental potential of intermediate neural progenitors (INPs) generated by asymmetrically dividing neural stem cells (neuroblasts). Here we demonstrate that the histone deacetylase Hdac1/Rpd3 functions together with self-renewal transcriptional repressors to maintain the erm immature INP enhancer in an inactive but poised state in neuroblasts. Within 2 hr of immature INP birth, downregulation of repressor activities alleviates Rpd3-mediated repression on the erm enhancer, enabling acetylation of multiple histone proteins and activating Erm expression. Erm restricts the developmental potential in immature INPs by repressing genes encoding neuroblast transcriptional activators. We propose that poising the fast-activating enhancers of master regulators of differentiation through continual histone deacetylation in stem cells enables self-renewal and rapid restriction of developmental potential following asymmetric division.
Collapse
Affiliation(s)
- Derek H Janssens
- Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Danielle C Hamm
- Department of Biomolecular Chemistry, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Lucas Anhezini
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Qi Xiao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Karsten H Siller
- Advanced Research Computing Services, University of Virginia, Charlottesville, VA 22904, USA
| | - Sarah E Siegrist
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Cheng-Yu Lee
- Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| |
Collapse
|
12
|
Urbach R, Jussen D, Technau GM. Gene expression profiles uncover individual identities of gnathal neuroblasts and serial homologies in the embryonic CNS of Drosophila. Development 2016; 143:1290-301. [PMID: 27095493 PMCID: PMC4852520 DOI: 10.1242/dev.133546] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/22/2016] [Indexed: 01/25/2023]
Abstract
The numbers and types of progeny cells generated by neural stem cells in the developing CNS are adapted to its region-specific functional requirements. In Drosophila, segmental units of the CNS develop from well-defined patterns of neuroblasts. Here we constructed comprehensive neuroblast maps for the three gnathal head segments. Based on the spatiotemporal pattern of neuroblast formation and the expression profiles of 46 marker genes (41 transcription factors), each neuroblast can be uniquely identified. Compared with the thoracic ground state, neuroblast numbers are progressively reduced in labial, maxillary and mandibular segments due to smaller sizes of neuroectodermal anlagen and, partially, to suppression of neuroblast formation and induction of programmed cell death by the Hox gene Deformed. Neuroblast patterns are further influenced by segmental modifications in dorsoventral and proneural gene expression. With the previously published neuroblast maps and those presented here for the gnathal region, all neuroectodermal neuroblasts building the CNS of the fly (ventral nerve cord and brain, except optic lobes) are now individually identified (in total 2×567 neuroblasts). This allows, for the first time, a comparison of the characteristics of segmental populations of stem cells and to screen for serially homologous neuroblasts throughout the CNS. We show that approximately half of the deutocerebral and all of the tritocerebral (posterior brain) and gnathal neuroblasts, but none of the protocerebral (anterior brain) neuroblasts, display serial homology to neuroblasts in thoracic/abdominal neuromeres. Modifications in the molecular signature of serially homologous neuroblasts are likely to determine the segment-specific characteristics of their lineages. Highlighted article: Characterisation of the neural stem cells in the gnathal head region completes the mapping of all individual neuroblasts that generate the Drosophila CNS.
Collapse
Affiliation(s)
- Rolf Urbach
- Institute of Genetics, University of Mainz, Mainz D-55099, Germany
| | - David Jussen
- Institute of Genetics, University of Mainz, Mainz D-55099, Germany
| | | |
Collapse
|
13
|
Kraft KF, Massey EM, Kolb D, Walldorf U, Urbach R. Retinal homeobox promotes cell growth, proliferation and survival of mushroom body neuroblasts in the Drosophila brain. Mech Dev 2016; 142:50-61. [PMID: 27455861 DOI: 10.1016/j.mod.2016.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/14/2016] [Accepted: 07/18/2016] [Indexed: 12/29/2022]
Abstract
The Drosophila mushroom bodies, centers of olfactory learning and memory in the fly 'forebrain', develop from a set of neural stem cells (neuroblasts) that generate a large number of Kenyon cells (KCs) during sustained cell divisions from embryonic to late pupal stage. We show that retinal homeobox (rx), encoding for an evolutionarily conserved transcription factor, is required for proper development of the mushroom bodies. Throughout development rx is expressed in mushroom body neuroblasts (MBNBs), their ganglion mother cells (MB-GMCs) and young KCs. In the absence of rx function, MBNBs form correctly but exhibit a reduction in cell size and mitotic activity, whereas overexpression of rx increases growth of MBNBs. These data suggest that Rx is involved in the control of MBNB growth and proliferation. Rx also promotes cell cycling of MB-GMCs. Moreover, we show that Rx is important for the survival of MBNBs and Kenyon cells which undergo premature cell death in the absence of rx function. Simultaneous blocking of cell death restores the normal set of MBNBs and part of the KCs, demonstrating that both, impaired proliferation and premature cell death (of MBNBs and KCs) account for the observed defects in mushroom body development. We then show that Rx controls proliferation within the MBNB clones independently of Tailless (Tll) and Prospero (Pros), and does not regulate the expression of other key regulators of MB development, Eyeless (Ey) and Dachshund (Dac). Our data support that the role of Rx in forebrain development is conserved between vertebrates and fly.
Collapse
Affiliation(s)
- Karoline F Kraft
- Institute of Genetics, University of Mainz, D-55099 Mainz, Germany
| | - Eva M Massey
- Institute of Genetics, University of Mainz, D-55099 Mainz, Germany
| | - Dieter Kolb
- Institute of Developmental Biology, Saarland University, D-66421 Homburg/Saar, Germany
| | - Uwe Walldorf
- Institute of Developmental Biology, Saarland University, D-66421 Homburg/Saar, Germany
| | - Rolf Urbach
- Institute of Genetics, University of Mainz, D-55099 Mainz, Germany.
| |
Collapse
|
14
|
Wolff T, Iyer NA, Rubin GM. Neuroarchitecture and neuroanatomy of the Drosophila central complex: A GAL4-based dissection of protocerebral bridge neurons and circuits. J Comp Neurol 2014; 523:997-1037. [PMID: 25380328 PMCID: PMC4407839 DOI: 10.1002/cne.23705] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 10/27/2014] [Accepted: 10/30/2014] [Indexed: 12/11/2022]
Abstract
Insects exhibit an elaborate repertoire of behaviors in response to environmental stimuli. The central complex plays a key role in combining various modalities of sensory information with an insect's internal state and past experience to select appropriate responses. Progress has been made in understanding the broad spectrum of outputs from the central complex neuropils and circuits involved in numerous behaviors. Many resident neurons have also been identified. However, the specific roles of these intricate structures and the functional connections between them remain largely obscure. Significant gains rely on obtaining a comprehensive catalog of the neurons and associated GAL4 lines that arborize within these brain regions, and on mapping neuronal pathways connecting these structures. To this end, small populations of neurons in the Drosophila melanogaster central complex were stochastically labeled using the multicolor flip-out technique and a catalog was created of the neurons, their morphologies, trajectories, relative arrangements, and corresponding GAL4 lines. This report focuses on one structure of the central complex, the protocerebral bridge, and identifies just 17 morphologically distinct cell types that arborize in this structure. This work also provides new insights into the anatomical structure of the four components of the central complex and its accessory neuropils. Most strikingly, we found that the protocerebral bridge contains 18 glomeruli, not 16, as previously believed. Revised wiring diagrams that take into account this updated architectural design are presented. This updated map of the Drosophila central complex will facilitate a deeper behavioral and physiological dissection of this sophisticated set of structures. J. Comp. Neurol. 523:997–1037, 2015. © 2014 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Tanya Wolff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, 20147
| | | | | |
Collapse
|
15
|
Iniguez J, Schutte SS, O'Dowd DK. Cav3-type α1T calcium channels mediate transient calcium currents that regulate repetitive firing in Drosophila antennal lobe PNs. J Neurophysiol 2013; 110:1490-6. [PMID: 23864373 DOI: 10.1152/jn.00368.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Projection neurons (PNs), located in the antennal lobe region of the insect brain, play a key role in processing olfactory information. To explore how activity is regulated at the level of single PNs within this central circuit we have recorded from these neurons in adult Drosophila melanogaster brains. Our previous study demonstrated that PNs express voltage-gated calcium currents with a transient and sustained component. We found that the sustained component is mediated by cac gene-encoded Cav2-type channels involved in regulating action potential-independent release of neurotransmitter at excitatory cholinergic synapses. The function of the transient calcium current and the gene encoding the underlying channels, however, were unknown. Here we report that the transient current blocked by prepulse inactivation is sensitive to amiloride, a vertebrate Cav3-type channel blocker. In addition PN-specific RNAi knockdown of α1T, the Drosophila Cav3-type gene, caused a dramatic reduction in the transient current without altering the sustained component. These data demonstrate that the α1T gene encodes voltage-gated calcium channels underlying the amiloride-sensitive transient current. Alterations in evoked firing and spontaneous burst firing in the α1T knockdowns demonstrate that the Cav3-type calcium channels are important in regulating excitability in adult PNs.
Collapse
Affiliation(s)
- Jorge Iniguez
- Department of Developmental and Cell Biology and Department of Anatomy and Neurobiology, University of California, Irvine, California
| | | | | |
Collapse
|