title: Long-term seizure suppression and optogenetic analyses of synaptic connectivity in epileptic mice with hippocampal grafts of GABAergic interneurons.
abstract: Studies in rodent epilepsy models suggest that GABAergic interneuron progenitor grafts can reduce hyperexcitability and seizures in temporal lobe epilepsy (TLE). Although integration of the transplanted cells has been proposed as the underlying mechanism for these disease-modifying effects, prior studies have not explicitly examined cell types and synaptic mechanisms for long-term seizure suppression. To address this gap, we transplanted medial ganglionic eminence (MGE) cells from embryonic day 13.5 VGAT-Venus or VGAT-ChR2-EYFP transgenic embryos into the dentate gyrus (DG) of adult mice 2 weeks after induction of TLE with pilocarpine. Beginning 3-4 weeks after status epilepticus, we conducted continuous video-electroencephalographic recording until 90-100 d. TLE mice with bilateral MGE cell grafts in the DG had significantly fewer and milder electrographic seizures, compared with TLE controls. Immunohistochemical studies showed that the transplants contained multiple neuropeptide or calcium-binding protein-expressing interneuron types and these cells established dense terminal arborizations onto the somas, apical dendrites, and axon initial segments of dentate granule cells (GCs). A majority of the synaptic terminals formed by the transplanted cells were apposed to large postsynaptic clusters of gephyrin, indicative of mature inhibitory synaptic complexes. Functionality of these new inhibitory synapses was demonstrated by optogenetically activating VGAT-ChR2-EYFP-expressing transplanted neurons, which generated robust hyperpolarizations in GCs. These findings suggest that fetal GABAergic interneuron grafts may suppress pharmacoresistant seizures by enhancing synaptic inhibition in DG neural circuits.
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Katharine W
authors.initials: KW
authors.lastname: Henderson
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Gupta
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Tagliatela
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170, Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115-5701.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Litvina
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: XiaoTing
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Meghan A
authors.initials: MA
authors.lastname: Van Zandt
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Woods
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Ethan
authors.initials: E
authors.lastname: Grund
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Diana
authors.initials: D
authors.lastname: Lin
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170, Medical Scholars Program, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, Illinois 61801-6210, and.
authors.forename: Sara
authors.initials: S
authors.lastname: Royston
authors.affiliation: Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Japan and Japan Science and Technology Agency, CREST, Tokyo 102-0075, Japan.
authors.forename: Yuchio
authors.initials: Y
authors.lastname: Yanagawa
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170.
authors.forename: Gloster B
authors.initials: GB
authors.lastname: Aaron
authors.affiliation: Department of Biology, Program in Neuroscience and Behavior, Hall-Atwater Laboratory, Wesleyan University, Middletown, Connecticut 06459-0170, jnaegele@wesleyan.edu.
authors.forename: Janice R
authors.identifier: http://orcid.org/0000-0001-5151-0543
authors.initials: JR
authors.lastname: Naegele
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D000075402:Channelrhodopsins; D004195:Disease Models, Animal; D004622:Embryo, Mammalian; D004827:Epilepsy / Q000601:surgery*; D059330:GABAergic Neurons / Q000502:physiology*; D005829:Geniculate Bodies / Q000166:cytology / Q000637:transplantation; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000378:metabolism / Q000502:physiology / Q000637:transplantation; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D055366:Synaptic Potentials / Q000502:physiology; D050495:Vesicular Inhibitory Amino Acid Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D000075402:Channelrhodopsins; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D050495:Vesicular Inhibitory Amino Acid Transport Proteins; C492244:Viaat protein, mouse; C054562:yellow fluorescent protein, Bacteria
keywords: EEG; GABA; epilepsy; seizures; transplantation