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Sun Y, Zhao Y, Johnson TK, Xie W. Immunohistochemical Analysis of the Drosophila Larval Neuromuscular Junction. Methods Mol Biol 2024; 2746:201-211. [PMID: 38070091 DOI: 10.1007/978-1-0716-3585-8_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Synapses are specialized junctions between cells that mediate neurotransmission to modify brain activity and body function. Studies on synapse structure and function play an important role in understanding how neurons communicate and the consequences of their dysfunction in neurological disorders. The Drosophila larval neuromuscular junction is an excellent model for dissecting the cellular and molecular mechanisms of the synapse, with its large size, accessibility, and well-characterized genetics. This protocol describes the steps required for morphological and immunohistochemical analysis of the Drosophila larval neuromuscular junction including its dissection and multiplex labeling of synaptic proteins. This technique can be used to assess the impact of genetic manipulations on synaptic development, integrity, and plasticity, thus providing a valuable tool for probing complex neurological processes in a whole animal system.
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Affiliation(s)
- Yichen Sun
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China.
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.
| | - Yu Zhao
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Travis K Johnson
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Biochemistry and Chemistry, and La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
| | - Wei Xie
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
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Jacot-Descombes S, Keshav NU, Dickstein DL, Wicinski B, Janssen WGM, Hiester LL, Sarfo EK, Warda T, Fam MM, Harony-Nicolas H, Buxbaum JD, Hof PR, Varghese M. Altered synaptic ultrastructure in the prefrontal cortex of Shank3-deficient rats. Mol Autism 2020; 11:89. [PMID: 33203459 PMCID: PMC7671669 DOI: 10.1186/s13229-020-00393-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/21/2020] [Indexed: 01/06/2023] Open
Abstract
Background Deletion or mutations of SHANK3 lead to Phelan–McDermid syndrome and monogenic forms of autism spectrum disorder (ASD). SHANK3 encodes its eponymous scaffolding protein at excitatory glutamatergic synapses. Altered morphology of dendrites and spines in the hippocampus, cerebellum, and striatum have been associated with behavioral impairments in Shank3-deficient animal models. Given the attentional deficit in these animals, our study explored whether deficiency of Shank3 in a rat model alters neuron morphology and synaptic ultrastructure in the medial prefrontal cortex (mPFC). Methods We assessed dendrite and spine morphology and spine density in mPFC layer III neurons in Shank3-homozygous knockout (Shank3-KO), heterozygous (Shank3-Het), and wild-type (WT) rats. We used electron microscopy to determine the density of asymmetric synapses in mPFC layer III excitatory neurons in these rats. We measured postsynaptic density (PSD) length, PSD area, and head diameter (HD) of spines at these synapses. Results Basal dendritic morphology was similar among the three genotypes. Spine density and morphology were comparable, but more thin and mushroom spines had larger head volumes in Shank3-Het compared to WT and Shank3-KO. All three groups had comparable synapse density and PSD length. Spine HD of total and non-perforated synapses in Shank3-Het rats, but not Shank3-KO rats, was significantly larger than in WT rats. The total and non-perforated PSD area was significantly larger in Shank3-Het rats compared to Shank3-KO rats. These findings represent preliminary evidence for synaptic ultrastructural alterations in the mPFC of rats that lack one copy of Shank3 and mimic the heterozygous loss of SHANK3 in Phelan–McDermid syndrome. Limitations The Shank3 deletion in the rat model we used does not affect all isoforms of the protein and would only model the effect of mutations resulting in loss of the N-terminus of the protein. Given the higher prevalence of ASD in males, the ultrastructural study focused only on synaptic structure in male Shank3-deficient rats. Conclusions We observed increased HD and PSD area in Shank3-Het rats. These observations suggest the occurrence of altered synaptic ultrastructure in this animal model, further pointing to a key role of defective expression of the Shank3 protein in ASD and Phelan–McDermid syndrome.
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Affiliation(s)
- Sarah Jacot-Descombes
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Unit of Psychiatry, Department of Children and Teenagers, University Hospital and School of Medicine, Geneva, Switzerland.,Department of Legal Medicine, University Hospital and School of Medicine, Geneva, Switzerland
| | - Neha U Keshav
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Dara L Dickstein
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Department of Pathology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences (USU), Bethesda, MD, USA
| | - Bridget Wicinski
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - William G M Janssen
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Liam L Hiester
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Edward K Sarfo
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tahia Warda
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Psychology Department, Rutgers University Brain Imaging Center (RUBIC), Rutgers University, Newark, NJ, 07102, USA
| | - Matthew M Fam
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hala Harony-Nicolas
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Joseph D Buxbaum
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Patrick R Hof
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA. .,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Merina Varghese
- Nash Family Department of Neuroscience, Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY, 10029, USA. .,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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