Spatial, temporal, and cell-type-specific expression of NADPH Oxidase isoforms following seizure models in rats
Aseel Saadi1, Sereen Sandouka1, Etty Grad1
1The Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel.
Abstract:
The NADPH Oxidase (NOX) enzymes are key producers of reactive oxygen species (ROS) and consist of seven different isoforms, distributed across the tissues and cell types. The increasing level of ROS induces oxidative stress playing a crucial role in neuronal death and the development of epilepsy. Recently, NOX2 was reported as a primary source of ROS production, activated by NMDA receptor, a crucial marker of epilepsy development. Here, we demonstrate spatial, temporal, and cellular expression of NOX2 and NOX4 complexes in in-vitro and in-vivo seizure models. We showed that the expression of NOX2 and NOX4 was increased in the initial 24 h following a brief seizure induced by pentylenetetrazol. Interestingly, while this elevated level returns to baseline 48 h following seizure in the cortex, in the hippocampus these levels remain elevated up to one week following the seizure. Moreover, we showed that 1- and 2- weeks following status epilepticus (SE), expression of NOX2 and NOX4 remains significantly elevated both in the cortex and the hippocampus. Furthermore, in in-vitro seizure model, NOX2 and NOX4 isoforms were overexpressed in neurons and astrocytes following seizures. These results suggest that NOX2 and NOX4 in the brain have a transient response to seizures, and these responses temporally vary depending on, seizure duration, brain region (cortex or hippocampus), and cell types.
Insights
NADPH Oxidase (NOX) enzymes, specifically NOX2 and NOX4, show altered expression following seizures. Their levels increase transiently in the brain, varying by seizure duration, region, and cell type.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- NADPH Oxidase (NOX) enzymes generate reactive oxygen species (ROS), contributing to oxidative stress implicated in neuronal death and epilepsy.
- NOX2, activated by NMDA receptors, is a key ROS producer and linked to epilepsy development.
Purpose of the Study:
- To investigate the spatial, temporal, and cellular expression patterns of NOX2 and NOX4 in in-vitro and in-vivo seizure models.
- To understand the dynamic response of NOX2 and NOX4 to seizures in different brain regions and cell types.
Main Methods:
- Utilized in-vitro and in-vivo seizure models.
- Analyzed the expression of NOX2 and NOX4 complexes following induced seizures (pentylenetetrazol) and status epilepticus (SE).
- Examined expression in cortical and hippocampal tissues, as well as in neurons and astrocytes.
Main Results:
- NOX2 and NOX4 expression increased within 24 hours after a brief seizure, returning to baseline in the cortex within 48 hours but remaining elevated in the hippocampus for up to a week.
- Following status epilepticus, NOX2 and NOX4 levels remained significantly elevated in both cortex and hippocampus for 1-2 weeks.
- In vitro, NOX2 and NOX4 were overexpressed in neurons and astrocytes post-seizure.
Conclusions:
- Brain NOX2 and NOX4 exhibit a transient, seizure-dependent expression response.
- The temporal dynamics of NOX2 and NOX4 expression vary based on seizure duration, brain region (cortex vs. hippocampus), and specific cell types (neurons vs. astrocytes).
