1
|
Santhakumar V, Subramanian D, Eisenberg C, Huang A, Baek J, Naveed H, Komatireddy S, Shiflett M, Tran T. Dysregulation of Neuropilin-2 Expression in Inhibitory Neurons Impairs Hippocampal Circuit Development Leading to Autism-Epilepsy Phenotype. RESEARCH SQUARE 2024:rs.3.rs-3922129. [PMID: 38405865 PMCID: PMC10889061 DOI: 10.21203/rs.3.rs-3922129/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Dysregulation of development, migration, and function of interneurons, collectively termed interneuronopathies, have been proposed as a shared mechanism for autism spectrum disorders (ASDs) and childhood epilepsy. Neuropilin-2 (Nrp2), a candidate ASD gene, is a critical regulator of interneuron migration from the median ganglionic eminence (MGE) to the pallium, including the hippocampus. While clinical studies have identified Nrp2 polymorphisms in patients with ASD, whether dysregulation of Nrp2-dependent interneuron migration contributes to pathogenesis of ASD and epilepsy has not been tested. We tested the hypothesis that the lack of Nrp2 in MGE-derived interneuron precursors disrupts the excitation/inhibition balance in hippocampal circuits, thus predisposing the network to seizures and behavioral patterns associated with ASD. Embryonic deletion of Nrp2 during the developmental period for migration of MGE derived interneuron precursors (iCKO) significantly reduced parvalbumin, neuropeptide Y, and somatostatin positive neurons in the hippocampal CA1. Consequently, when compared to controls, the frequency of inhibitory synaptic currents in CA1 pyramidal cells was reduced while frequency of excitatory synaptic currents was increased in iCKO mice. Although passive and active membrane properties of CA1 pyramidal cells were unchanged, iCKO mice showed enhanced susceptibility to chemically evoked seizures. Moreover, iCKO mice exhibited selective behavioral deficits in both preference for social novelty and goal-directed learning, which are consistent with ASD-like phenotype. Together, our findings show that disruption of developmental Nrp2 regulation of interneuron circuit establishment, produces ASD-like behaviors and enhanced risk for epilepsy. These results support the developmental interneuronopathy hypothesis of ASD epilepsy comorbidity.
Collapse
|
2
|
Subramanian D, Eisenberg C, Huang A, Baek J, Naveed H, Komatireddy S, Shiflett MW, Tran TS, Santhakumar V. Dysregulation of Neuropilin-2 Expression in Inhibitory Neurons Impairs Hippocampal Circuit Development Leading to Autism-Epilepsy Phenotype. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.05.578976. [PMID: 38370800 PMCID: PMC10871171 DOI: 10.1101/2024.02.05.578976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Dysregulation of development, migration, and function of interneurons, collectively termed interneuronopathies, have been proposed as a shared mechanism for autism spectrum disorders (ASDs) and childhood epilepsy. Neuropilin-2 (Nrp2), a candidate ASD gene, is a critical regulator of interneuron migration from the median ganglionic eminence (MGE) to the pallium, including the hippocampus. While clinical studies have identified Nrp2 polymorphisms in patients with ASD, whether dysregulation of Nrp2-dependent interneuron migration contributes to pathogenesis of ASD and epilepsy has not been tested. We tested the hypothesis that the lack of Nrp2 in MGE-derived interneuron precursors disrupts the excitation/inhibition balance in hippocampal circuits, thus predisposing the network to seizures and behavioral patterns associated with ASD. Embryonic deletion of Nrp2 during the developmental period for migration of MGE derived interneuron precursors (iCKO) significantly reduced parvalbumin, neuropeptide Y, and somatostatin positive neurons in the hippocampal CA1. Consequently, when compared to controls, the frequency of inhibitory synaptic currents in CA1 pyramidal cells was reduced while frequency of excitatory synaptic currents was increased in iCKO mice. Although passive and active membrane properties of CA1 pyramidal cells were unchanged, iCKO mice showed enhanced susceptibility to chemically evoked seizures. Moreover, iCKO mice exhibited selective behavioral deficits in both preference for social novelty and goal-directed learning, which are consistent with ASD-like phenotype. Together, our findings show that disruption of developmental Nrp2 regulation of interneuron circuit establishment, produces ASD-like behaviors and enhanced risk for epilepsy. These results support the developmental interneuronopathy hypothesis of ASD epilepsy comorbidity.
Collapse
Affiliation(s)
- Deepak Subramanian
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA
| | - Carol Eisenberg
- Department of Biological Sciences, Rutgers University, Newark, NJ
| | - Andrew Huang
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA
- Division of Biomedical Sciences, University of California Riverside, Riverside, CA
| | - Jiyeon Baek
- Department of Biological Sciences, Rutgers University, Newark, NJ
| | - Haniya Naveed
- Department of Biological Sciences, Rutgers University, Newark, NJ
| | - Samiksha Komatireddy
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA
| | | | - Tracy S. Tran
- Department of Biological Sciences, Rutgers University, Newark, NJ
| | - Vijayalakshmi Santhakumar
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA
- Division of Biomedical Sciences, University of California Riverside, Riverside, CA
| |
Collapse
|
3
|
Jahncke JN, Miller DS, Krush M, Schnell E, Wright KM. Inhibitory CCK+ basket synapse defects in mouse models of dystroglycanopathy. eLife 2024; 12:RP87965. [PMID: 38179984 PMCID: PMC10942650 DOI: 10.7554/elife.87965] [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] [Indexed: 01/06/2024] Open
Abstract
Dystroglycan (Dag1) is a transmembrane glycoprotein that links the extracellular matrix to the actin cytoskeleton. Mutations in Dag1 or the genes required for its glycosylation result in dystroglycanopathy, a type of congenital muscular dystrophy characterized by a wide range of phenotypes including muscle weakness, brain defects, and cognitive impairment. We investigated interneuron (IN) development, synaptic function, and associated seizure susceptibility in multiple mouse models that reflect the wide phenotypic range of dystroglycanopathy neuropathology. Mice that model severe dystroglycanopathy due to forebrain deletion of Dag1 or Pomt2, which is required for Dystroglycan glycosylation, show significant impairment of CCK+/CB1R+ IN development. CCK+/CB1R+ IN axons failed to properly target the somatodendritic compartment of pyramidal neurons in the hippocampus, resulting in synaptic defects and increased seizure susceptibility. Mice lacking the intracellular domain of Dystroglycan have milder defects in CCK+/CB1R+ IN axon targeting, but exhibit dramatic changes in inhibitory synaptic function, indicating a critical postsynaptic role of this domain. In contrast, CCK+/CB1R+ IN synaptic function and seizure susceptibility was normal in mice that model mild dystroglycanopathy due to partially reduced Dystroglycan glycosylation. Collectively, these data show that inhibitory synaptic defects and elevated seizure susceptibility are hallmarks of severe dystroglycanopathy, and show that Dystroglycan plays an important role in organizing functional inhibitory synapse assembly.
Collapse
Affiliation(s)
- Jennifer N Jahncke
- Neuroscience Graduate Program, Oregon Health & Science UniversityPortlandUnited States
| | - Daniel S Miller
- Neuroscience Graduate Program, Oregon Health & Science UniversityPortlandUnited States
| | - Milana Krush
- Neuroscience Graduate Program, Oregon Health & Science UniversityPortlandUnited States
| | - Eric Schnell
- Operative Care Division, Portland VA Health Care SystemPortlandUnited States
- Anesthesiology and Perioperative Medicine, Oregon Health & Science UniversityPortlandUnited States
| | - Kevin M Wright
- Vollum Institute, Oregon Health & Science UniversityPortlandUnited States
| |
Collapse
|