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Rac1 Modulates Excitatory Synaptic Transmission in Mouse Retinal Ganglion Cells. Neurosci Bull 2019; 35:673-687. [PMID: 30888607 DOI: 10.1007/s12264-019-00353-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/21/2018] [Indexed: 10/26/2022] Open
Abstract
Ras-related C3 botulinum toxin substrate 1 (Rac1), a member of the Rho GTPase family which plays important roles in dendritic spine morphology and plasticity, is a key regulator of cytoskeletal reorganization in dendrites and spines. Here, we investigated whether and how Rac1 modulates synaptic transmission in mouse retinal ganglion cells (RGCs) using selective conditional knockout of Rac1 (Rac1-cKO). Rac1-cKO significantly reduced the frequency of AMPA receptor-mediated miniature excitatory postsynaptic currents, while glycine/GABAA receptor-mediated miniature inhibitory postsynaptic currents were not affected. Although the total GluA1 protein level was increased in Rac1-cKO mice, its expression in the membrane component was unchanged. Rac1-cKO did not affect spine-like branch density in single dendrites, but significantly reduced the dendritic complexity, which resulted in a decrease in the total number of dendritic spine-like branches. These results suggest that Rac1 selectively affects excitatory synaptic transmission in RGCs by modulating dendritic complexity.
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Palfi A, Hokamp K, Hauck SM, Vencken S, Millington-Ward S, Chadderton N, Carrigan M, Kortvely E, Greene CM, Kenna PF, Farrar GJ. microRNA regulatory circuits in a mouse model of inherited retinal degeneration. Sci Rep 2016; 6:31431. [PMID: 27527066 PMCID: PMC4985623 DOI: 10.1038/srep31431] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/18/2016] [Indexed: 12/14/2022] Open
Abstract
miRNA dysregulation is a hallmark of many neurodegenerative disorders, including those involving the retina. Up-regulation of miR-1/133 and miR-142, and down-regulation of miR-183/96/182 has been described in the RHO-P347S mouse retina, a model for a common form of inherited blindness. High-throughput LC-MS/MS was employed to analyse the protein expression of predicted targets for these miRNAs in RHO-P347S mouse retinas; 133 potential target genes were identified. Pathway over-representation analysis suggests G-protein signaling/visual transduction, and synaptic transmission for miR-1, and transmembrane transport, cell-adhesion, signal transduction and apoptosis for miR-183/96/182 as regulated functions in retina. Validation of miRNA-target mRNA interactions for miR-1, miR-96/182 and miR-96 targeting Ctbp2, Rac1 and Slc6a9, respectively, was demonstrated in vitro. In vivo interaction of miR-183/96/182 and Rac1 mRNA in retina was confirmed using miR-CATCH. Additional miRNAs (including miR-103-3p, miR-9-5p) were both predicted to target Rac1 mRNA and enriched by Rac1-miR-CATCH. Other Rac1-miR-CATCH-enriched miRNAs (including miR-125a/b-5p, miR-378a-3p) were not predicted to target Rac1. Furthermore, levels of ~25% of the retinal Rac1 interactors were determined by LC-MS/MS; expression of Rap1gds1 and Cav1 was elevated. Our data suggest significant utilisation of miRNA-based regulation in retina. Possibly more than 30 miRNAs interact with Rac1 in retina, targeting both UTRs and coding regions.
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Affiliation(s)
- Arpad Palfi
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Karsten Hokamp
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Stefanie M. Hauck
- Research Unit Protein Science, Helmholtz Zentrum Munchen - German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Sebastian Vencken
- Respiratory Research Division, Dept. Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | | | - Naomi Chadderton
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Mathew Carrigan
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Elod Kortvely
- Institute of Ophthalmic Research, Center for Ophthalmology, University of Tubingen, Tubingen, Germany
| | - Catherine M. Greene
- Respiratory Research Division, Dept. Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - Paul F. Kenna
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - G. Jane Farrar
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
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