ePoster

DREADD-based manipulation of hippocampal astrocyte Gq signalling in a chronic mouse model of medial temporal lobe epilepsy

Dimitri De Bundel, Yana Van Den Herrewegen, Surajit Sahu, Marcus Dyer, Liam Nestor, Ann Van Eeckaut, Ilse Smolders
FENS Forum 2024(2024)
Messe Wien Exhibition & Congress Center, Vienna, Austria

Conference

FENS Forum 2024

Messe Wien Exhibition & Congress Center, Vienna, Austria

Resources

Authors & Affiliations

Dimitri De Bundel, Yana Van Den Herrewegen, Surajit Sahu, Marcus Dyer, Liam Nestor, Ann Van Eeckaut, Ilse Smolders

Abstract

Medial temporal lobe epilepsy (MTLE) is a common cause of treatment-resistant seizures where excessive and hyper-synchronized neuronal activity is associated with reactive astrogliosis. Emerging evidence has indicated a role for neuron-astrocyte interactions in seizure activity. Previous studies have found increased astrocyte Ca2+ signals in mouse models for MTLE, but it has been difficult to disentangle how these drive or mitigate seizure activity in chronic epilepsy. We used an AAV8-GFAP-hM3Dq-mCherry vector to manipulate reactive astrocytes in the chronic phase of the mouse intrahippocampal kainic acid (IHKA) model. This vector drives the expression of a Gq coupled designer receptor exclusively activated by designer drugs (DREADDs) that increases Ca2+ transients in astrocytes. We controlled for non-specific effects using mice expressing the AAV8-GFAP-mCherry vector. We ascertained specific targeting of hippocampal astrocytes by immunohistochemistry and observed increased c-Fos expression specifically in hM3Dq transfected astrocytes of IHKA mice injected with the DREADD agonist CNO. Intriguingly, administration of CNO led to a slow decrease in seizure frequency that lasted up to one day in hM3Dq transfected IHKA mice but not in controls. This effect of astrocyte Gq DREADD activation was associated with a normalization of some measures of hippocampal energy metabolism and synaptic activity in IHKA mice. However, repeated daily injections of CNO led to a rebound in seizure frequency and a progressive increase in seizure duration in hM3Dq transfected IHKA mice. Consequentially, long-term activation of astrocyte Gq signalling did not improve anhedonia nor spatial memory function in the IHKA mouse model for epilepsy.

Unique ID: fens-24/dreadd-based-manipulation-hippocampal-1b7c70bf