Mechanisms of disease-modifying effect of saracatinib (AZD0530), a Src/Fyn tyrosine kinase inhibitor, in the rat kainate model of temporal lobe epilepsy

• Published in: Neurobiology of disease Vol. 156; p. 105410
• Main Authors: Sharma, Shaunik, Carlson, Steven, Gregory-Flores, Adriana, Hinojo-Perez, Andy, Olson, Ashley, Thippeswamy, Thimmasettappa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2021; Elsevier
• Subjects: Animals; Benzodioxoles - pharmacology; Benzodioxoles - therapeutic use; Disease Models, Animal; Electroencephalography - methods; Enzyme Inhibitors - pharmacology; Enzyme Inhibitors - therapeutic use; Epilepsy, Temporal Lobe - chemically induced; Epilepsy, Temporal Lobe - drug therapy; Epilepsy, Temporal Lobe - metabolism; Epileptogenesis; Fyn/Src tyrosine kinase; Inflammation Mediators - antagonists & inhibitors; Inflammation Mediators - metabolism; Kainic Acid - toxicity; Male; NADPH oxidase 2; Neuroinflammation; Nitroxidative stress; Proinflammatory cytokines; Protein kinase C delta; Proto-Oncogene Proteins c-fyn - antagonists & inhibitors; Proto-Oncogene Proteins c-fyn - metabolism; Quinazolines - pharmacology; Quinazolines - therapeutic use; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species - antagonists & inhibitors; Reactive Oxygen Species - metabolism; Spontaneous seizures; Telemetry - methods; Protein kinase C delta; Epileptogenesis; Nitroxidative stress; Neuroinflammation; Spontaneous seizures; Proinflammatory cytokines; Fyn/Src tyrosine kinase; NADPH oxidase 2
• ISSN: 0969-9961; 1095-953X
• DOI: 10.1016/j.nbd.2021.105410

We have recently demonstrated the role of the Fyn-PKCδ signaling pathway in status epilepticus (SE)-induced neuroinflammation and epileptogenesis in experimental models of temporal lobe epilepsy (TLE). In this study, we show a significant disease-modifying effect and the mechanisms of a Fyn/Src tyrosine kinase inhibitor, saracatinib (SAR, also known as AZD0530), in the rat kainate (KA) model of TLE. SAR treatment for a week, starting the first dose (25 mg/kg, oral) 4 h after the onset of SE, significantly reduced spontaneously recurring seizures and epileptiform spikes during the four months of continuous video-EEG monitoring. Immunohistochemistry of brain sections and Western blot analyses of hippocampal lysates at 8-day (8d) and 4-month post-SE revealed a significant reduction of SE-induced astrogliosis, microgliosis, neurodegeneration, phosphorylated Fyn/Src-419 and PKCδ-tyr311, in SAR-treated group when compared with the vehicle control. We also found the suppression of nitroxidative stress markers such as iNOS, 3-NT, 4-HNE, and gp91phox in the hippocampus, and nitrite and ROS levels in the serum of the SAR-treated group at 8d post-SE. The qRT-PCR (hippocampus) and ELISA (serum) revealed a significant reduction of key proinflammatory cytokines TNFα and IL-1β mRNA in the hippocampus and their protein levels in serum, in addition to IL-6 and IL-12, in the SAR-treated group at 8d in contrast to the vehicle-treated group. These findings suggest that SAR targets some of the key biomarkers of epileptogenesis and modulates neuroinflammatory and nitroxidative pathways that mediate the development of epilepsy. Therefore, SAR can be developed as a potential disease-modifying agent to prevent the development and progression of TLE. [Display omitted] •SAR treatment for a week reduced spike rate and SRS in a 4-month video-EEG study.•SAR mitigated SE-induced pSrc-416 and pPKCδ-Ty311, and reactive gliosis.•SAR suppressed nitroxidative stress mediators- iNOS, 3-NT, 4-HNE, and gp91PHOX.•SAR reduced SE-induced IL1β and TNFα in both hippocampus and serum at 8d post-SE.•SAR prevented SE-induced neuroinflammation and neurodegeneration.