Saracatinib, a Src Tyrosine Kinase Inhibitor, as a Disease Modifier in the Rat DFP Model: Sex Differences, Neurobehavior, Gliosis, Neurodegeneration, and Nitro-Oxidative Stress

Gage, Meghan; Putra, Marson; Wachter, Logan; Dishman, Kylie; Gard, Megan; Gomez-Estrada, Crystal; Thippeswamy, Thimmasettappa

doi:10.3390/antiox11010061

Cited by 18 publications

(34 citation statements)

References 161 publications

(203 reference statements)

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“…It is well established that epilepsy is associated with abnormal regulation and excessive proliferation of glial cells ( Vezzani et al, 2015 ). Our previous studies and others’ studies have demonstrated that DFP-induced epilepsy is also characterized by neuroinflammation and neurodegeneration ( Gage et al, 2021a ; Gage et al, 2021b ; Guignet et al, 2019 ; Putra et al, 2020a ). Reactive astrogliosis exists on a spectrum ranging from hypertrophy of astrocytes and progressing into the formation of a glial scar ( Sofroniew, 2005 ; Pekny and Pekna, 2016 ).…”

Section: Discussionmentioning

confidence: 90%

“…Prior to MDZ, animals were scored on each minute for seizure stage based on a modified Racine scale ( Racine, 1972 ) as described in our previous publications ( Putra et al, 2020b ; Gage et al, 2021b ; Sharma et al, 2021 ). Stage one was characterized by salivation, lacrimation, urination, defecation, and mastication, while stage two was characterized by head nodding and tremors.…”

Section: Methodsmentioning

confidence: 99%

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Characterization of Cortical Glial Scars in the Diisopropylfluorophosphate (DFP) Rat Model of Epilepsy

Gage

Gard

Thippeswamy

2022

Front. Cell Dev. Biol.

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Glial scars have been observed following stab lesions in the spinal cord and brain but not observed and characterized in chemoconvulsant-induced epilepsy models. Epilepsy is a disorder characterized by spontaneous recurrent seizures and can be modeled in rodents. Diisopropylfluorophosphate (DFP) exposure, like other real-world organophosphate nerve agents (OPNAs) used in chemical warfare scenarios, can lead to the development of status epilepticus (SE). We have previously demonstrated that DFP-induced SE promotes epileptogenesis which is characterized by the development of spontaneous recurrent seizures (SRS), gliosis, and neurodegeneration. In this study, we report classical glial scars developed in the piriform cortex, but not in the hippocampus, by 8 days post-exposure. We challenged both male and female rats with 4–5 mg/kg DFP (s.c.) followed immediately by 2 mg/kg atropine sulfate (i.m.) and 25 mg/kg pralidoxime (i.m.) and one hour later by midazolam (i.m). Glial scars were present in the piriform cortex/amygdala region in 73% of the DFP treated animals. No scars were found in controls. Scars were characterized by a massive clustering of reactive microglia surrounded by hypertrophic reactive astrocytes. The core of the scars was filled with a significant increase of IBA1 and CD68 positive cells and a significant reduction in NeuN positive cells compared to the periphery of the scars. There was a significantly higher density of reactive GFAP, complement 3 (C3), and inducible nitric oxide synthase (iNOS) positive cells at the periphery of the scar compared to similar areas in controls. We found a significant increase in chondroitin sulfate proteoglycans (CS-56) in the periphery of the scars compared to a similar region in control brains. However, there was no change in TGF-β1 or TGF-β2 positive cells in or around the scars in DFP-exposed animals compared to controls. In contrast to stab-induced scars, we did not find fibroblasts (Thy1.1) in the scar core or periphery. There were sex differences with respect to the density of iNOS, CD68, NeuN, GFAP, C3 and CS-56 positive cells. This is the first report of cortical glial scars in rodents with systemic chemoconvulsant-induced SE. Further investigation could help to elucidate the mechanisms of scar development and mitigation strategies.

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Section: Discussionmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Characterization of Cortical Glial Scars in the Diisopropylfluorophosphate (DFP) Rat Model of Epilepsy

Gage

Gard

Thippeswamy

2022

Front. Cell Dev. Biol.

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“…The source of the DFP was from the same company (Sigma Aldrich, United States ) for all our experiments, but the batches were different. In our previous studies, female rats always received higher doses than males to achieve a similar SE severity ( Gage et al, 2020 ; 2021a ; 2021b ; 2022a ). In this study, we also used the DFP from different batches but the same vendor as our previous studies.…”

Section: Discussionmentioning

confidence: 87%

DFP-Induced Status Epilepticus Severity in Mixed-Sex Cohorts of Adult Rats Housed in the Same Room: Behavioral and EEG Comparisons

Gage

Thippeswamy

2022

Front. Cell Dev. Biol.

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Sex is a biological variable in experimental models. In our previous diisopropylfluorophosphate (DFP) studies, female rats required a higher dose of DFP to achieve a somewhat similar severity of status epilepticus (SE) as males. In those studies, male and female rats were bought separately from the same vendor, housed in different rooms, and the DFP used was from different batches. We had also shown that surgery for epidural electrodes implantation reduces the threshold for SE. Our recent study in the soman (GD) model using a mixed-sex cohort of rats housed individually but in the same room showed that females achieved significantly higher SE severity than males for the same dose of GD. In this study, we demonstrate that housing the mixed-sex cohorts in the same room and treating them with DFP (4 mg/kg, s.c.) from the same pool, though from different batches, yielded reproducible SE severity in both sexes and both telemetry (surgery) and non-telemetry (non-surgery) groups. We conducted experiments in four mixed-sex cohorts of adult Sprague-Dawley rats. In females, the surgery for implanting the telemetry devices reduced the latency to convulsive seizure (CS) and increased SE severity compared to non-telemetry females. However, there were no sex differences in latency or SE severity within telemetry or non-telemetry groups. Once animals reached CS stage ≥3, they remained in CS stage in both sexes until midazolam was administered. Midazolam (3 mg/kg, i.m.) treatment 1-one-hour post-DFP significantly reduced epileptiform spikes in both sexes. The mortality was only 2% in 24 h. Irrespective of sex or stage of estrous cycle or surgery, the animals had continuous convulsive SE for ∼40 min. In telemetry rats, electrographic changes correlated with behavioral seizures. However, there was a significant difference in SE severity and the latency between directly-observed behavioral CS and EEG-based CS quantification in both sexes. Overall, these results suggest that housing both sexes in the same room and treating with DFP in a mixed-sex cohort from the same pool of reagents will minimize variability in SE severity. Such rigorous experiments will yield better outcomes while testing disease-modifying agents in epilepsy models.

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“…Saracatinib is an Src inhibitor that also inhibits Fyn, c-Yes, Lyn, BLK, FGR, and Lck and has been shown to reduce glial hyperplasia, neurodegeneration, and nitro-oxidative stress [ 96 ]. On123300 is a multi-target kinase inhibitor that inhibits CDK4, ark5/nuak1, PDGFR, FGFR1, RET (c-RET), and Fyn.…”

Section: The Potential Of Fyn As a Therapeutic Target For Strokementioning

confidence: 99%

“…Preclinical studies in rodents with Fyn inhibitors suggest that targeting this kinase family may be beneficial in humans to prevent ischemic brain injury (Table 1 [95]. Saracatinib is an Src inhibitor that also Fyn, c-Yes, Lyn, BLK, FGR, and Lck and has been shown to reduce glial hyperplasia, neurodegeneration, and nitro-oxidative stress [96]. On123300 is a multi-target kinase inhibitor that inhibits CDK4, ark5/nuak1, PDGFR, FGFR1, RET (c-RET), and Fyn.…”

Section: The Potential Of Fyn As a Therapeuticmentioning

confidence: 99%

Fyn Signaling in Ischemia-Reperfusion Injury: Potential and Therapeutic Implications

Tang

et al. 2022

Mediators of Inflammation

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Ischemic stroke caused by arterial occlusion is the most common type of stroke and is one of the leading causes of disability and death, with the incidence increasing each year. Fyn is a nonreceptor tyrosine kinase belonging to the Src family of kinases (SFKs), which is related to many normal and pathological processes of the nervous system, including neurodevelopment and disease progression. In recent years, more and more evidence suggests that Fyn may be closely related to cerebral ischemia-reperfusion, including energy metabolism disorders, excitatory neurotoxicity, intracellular calcium homeostasis, free radical production, and the activation of apoptotic genes. This paper reviews the role of Fyn in the pathological process of cerebral ischemia-reperfusion, including neuroexcitotoxicity and neuroinflammation, to explore how Fyn affects specific signal cascades and leads to cerebral ischemia-reperfusion injury. In addition, Fyn also promotes the production of superoxide and endogenous NO, so as to quickly react to produce peroxynitrite, which may also mediate cerebral ischemia-reperfusion injury, which is discussed in this paper. Finally, we revealed the treatment methods related to Fyn inhibitors and discussed its potential as a clinical treatment for ischemic stroke.

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Saracatinib, a Src Tyrosine Kinase Inhibitor, as a Disease Modifier in the Rat DFP Model: Sex Differences, Neurobehavior, Gliosis, Neurodegeneration, and Nitro-Oxidative Stress

Cited by 18 publications

References 161 publications

Characterization of Cortical Glial Scars in the Diisopropylfluorophosphate (DFP) Rat Model of Epilepsy

Characterization of Cortical Glial Scars in the Diisopropylfluorophosphate (DFP) Rat Model of Epilepsy

DFP-Induced Status Epilepticus Severity in Mixed-Sex Cohorts of Adult Rats Housed in the Same Room: Behavioral and EEG Comparisons

Fyn Signaling in Ischemia-Reperfusion Injury: Potential and Therapeutic Implications

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