TY - JOUR
T1 - The role of astrocytes in seizure generation
T2 - Insights from a novel in vitro seizure model based on mitochondrial dysfunction
AU - Chan, Felix
AU - Lax, Nichola Z.
AU - Voss, Caroline Marie
AU - Aldana, Blanca Irene
AU - Whyte, Shuna
AU - Jenkins, Alistair
AU - Nicholson, Claire
AU - Nichols, Sophie
AU - Tilley, Elizabeth
AU - Powell, Zoe
AU - Waagepetersen, Helle S.
AU - Davies, Ceri H.
AU - Turnbull, Doug M.
AU - Cunningham, Mark O.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Approximately one-quarter of patients with mitochondrial disease experience epilepsy. Their epilepsy is often severe and resistant towards conventional antiepileptic drugs. Despite the severity of this epilepsy, there are currently no animal models available to provide a mechanistic understanding of mitochondrial epilepsy. We conducted neuropathological studies on patients with mitochondrial epilepsy and found the involvement of the astrocytic compartment. As a proof of concept, we developed a novel brain slice model of mitochondrial epilepsy by the application of an astrocytic-specific aconitase inhibitor, fluorocitrate, concomitant with mitochondrial respiratory inhibitors, rotenone and potassium cyanide. The model was robust and exhibited both face and predictive validity. We then used the model to assess the role that astrocytes play in seizure generation and demonstrated the involvement of the GABA-glutamate-glutamine cycle. Notably, glutamine appears to be an important intermediary molecule between the neuronal and astrocytic compartment in the regulation of GABAergic inhibitory tone. Finally, we found that a deficiency in glutamine synthetase is an important pathogenic process for seizure generation in both the brain slice model and the human neuropathological study. Our study describes the first model for mitochondrial epilepsy and provides a mechanistic insight into how astrocytes drive seizure generation in mitochondrial epilepsy.
AB - Approximately one-quarter of patients with mitochondrial disease experience epilepsy. Their epilepsy is often severe and resistant towards conventional antiepileptic drugs. Despite the severity of this epilepsy, there are currently no animal models available to provide a mechanistic understanding of mitochondrial epilepsy. We conducted neuropathological studies on patients with mitochondrial epilepsy and found the involvement of the astrocytic compartment. As a proof of concept, we developed a novel brain slice model of mitochondrial epilepsy by the application of an astrocytic-specific aconitase inhibitor, fluorocitrate, concomitant with mitochondrial respiratory inhibitors, rotenone and potassium cyanide. The model was robust and exhibited both face and predictive validity. We then used the model to assess the role that astrocytes play in seizure generation and demonstrated the involvement of the GABA-glutamate-glutamine cycle. Notably, glutamine appears to be an important intermediary molecule between the neuronal and astrocytic compartment in the regulation of GABAergic inhibitory tone. Finally, we found that a deficiency in glutamine synthetase is an important pathogenic process for seizure generation in both the brain slice model and the human neuropathological study. Our study describes the first model for mitochondrial epilepsy and provides a mechanistic insight into how astrocytes drive seizure generation in mitochondrial epilepsy.
KW - astrocytes
KW - GABA-glutamate-glutamine cycle
KW - glutamine synthetase
KW - mitochondrial epilepsy
U2 - 10.1093/brain/awy320
DO - 10.1093/brain/awy320
M3 - Journal article
C2 - 30689758
AN - SCOPUS:85060806232
SN - 0006-8950
VL - 142
SP - 391
EP - 411
JO - Brain
JF - Brain
IS - 2
ER -