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Pun RY, Rolle IJ, LaSarge CL, Hosford BE, Rosen JM, Uhl JD, Schmeltzer SN, Faulkner C, Bronson SL, Murphy BL, Richards DA, Holland KD, Danzer SC. Excessive activation of mTOR in postnatally generated granule cells is sufficient to cause epilepsy. Neuron 2012; 75:1022-34. [PMID: 22998871 PMCID: PMC3474536 DOI: 10.1016/j.neuron.2012.08.002] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2012] [Indexed: 12/30/2022]
Abstract
The dentate gyrus is hypothesized to function as a "gate," limiting the flow of excitation through the hippocampus. During epileptogenesis, adult-generated granule cells (DGCs) form aberrant neuronal connections with neighboring DGCs, disrupting the dentate gate. Hyperactivation of the mTOR signaling pathway is implicated in driving this aberrant circuit formation. While the presence of abnormal DGCs in epilepsy has been known for decades, direct evidence linking abnormal DGCs to seizures has been lacking. Here, we isolate the effects of abnormal DGCs using a transgenic mouse model to selectively delete PTEN from postnatally generated DGCs. PTEN deletion led to hyperactivation of the mTOR pathway, producing abnormal DGCs morphologically similar to those in epilepsy. Strikingly, animals in which PTEN was deleted from ≥ 9% of the DGC population developed spontaneous seizures in about 4 weeks, confirming that abnormal DGCs, which are present in both animals and humans with epilepsy, are capable of causing the disease.
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Affiliation(s)
- Raymund Y.K. Pun
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
| | - Isaiah J. Rolle
- Program in Neuroscience, University of Cincinnati, Cincinnati, OH, 45267
| | - Candi L. LaSarge
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
| | - Bethany E. Hosford
- Program in Neuroscience, University of Cincinnati, Cincinnati, OH, 45267
| | - Jules M. Rosen
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
| | - Juli D. Uhl
- Division of Molecular and Developmental Biology, Cincinnati Children’s Hospital Medical Centre Research Foundation, Cincinnati, OH, 45229
| | | | - Christian Faulkner
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
| | | | - Brian L. Murphy
- Program in Neuroscience, University of Cincinnati, Cincinnati, OH, 45267
| | - David A. Richards
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
- Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, OH, 45267
- Program in Neuroscience, University of Cincinnati, Cincinnati, OH, 45267
| | - Katherine D. Holland
- Department of Neurology, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
| | - Steve C. Danzer
- Department of Anesthesia, Cincinnati Children’s Hospital Medical Centre, Cincinnati, OH, 45229
- Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, OH, 45267
- Program in Neuroscience, University of Cincinnati, Cincinnati, OH, 45267
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