1400 W, a selective inducible nitric oxide synthase inhibitor, mitigates early neuroinflammation and nitrooxidative stress in diisopropylfluorophosphate-induced short-term neurotoxicity rat model

Abstract

Organophosphate nerve agent (OPNA) exposure induces acute and long-term neurological deficits. OPNA exposure at sub-lethal concentrations induces irreversible inhibition of acetylcholinesterase and cholinergic toxidrome and develops status epilepticus (SE). Persistent seizures have been associated with increased production of ROS/RNS, neuroinflammation, and neurodegeneration. A total of 1400W is a novel small molecule, which irreversibly inhibits inducible nitric oxide synthase (iNOS) and has been shown to effectively reduce ROS/RNS generation. In this study, we investigated the effects of 1400W treatment for a week or two weeks at 10 mg/kg or 15 mg/kg per day in the rat diisopropylfluorophosphate (DFP) model. 1400W significantly reduced the number of microglia, astroglia, and NeuN+FJB positive cells compared to the vehicle in different regions of the brain. 1400W also significantly reduced nitrooxidative stress markers and proinflammatory cytokines in the serum. However, neither of the two concentrations of 1400W for two weeks of treatment had any significant effect on epileptiform spike rate and spontaneous seizures during the treatment period in mixed sex cohorts, males, or females. No significant sex differences were found in response to DFP exposure or 1400W treatment. In conclusion, 1400W treatment at 15 mg/kg per day for two weeks was more effective in significantly reducing DFP-induced nitrooxidative stress, neuroinflammatory and neurodegenerative changes.

Disease-modifying effects of a glial-targeted inducible nitric oxide synthase inhibitor (1400W) in mixed-sex cohorts of a rat soman (GD) model of epilepsy

“…Our previous study demonstrated a significant increase in the inducible nitric oxide synthase (iNOS) in the brains of OPNA exposed adult rats, which persisted for long-term in glial cells [ 14 ]. Treatment with a highly selective iNOS inhibitor, 1400W hydrochloride, suppressed serum nitrite production and also reduced iNOS levels in the brain [ 14 , 15 ]. In addition, we found a significant increase in neuronal nitric oxide synthase (nNOS) post-SE, but unlike iNOS, it was only transiently upregulated [ 16 , 17 ].…”

Inhibition of superoxide and iNOS augment cutaneous nitric oxide‐dependent vasodilation in non‐Hispanic black young adults

“…Both the 1400 W site and the tempol + 1400 W site were found to be greater than the tempol site for both the plateau and NO-dependent vasodilation. This was supported not only statistically but also based on the range of effect sizes of d = 1.03-1.22, indicating significant physiological differences in the effects of tempol compared to 1400 W. Mechanistically, it's possible 1400 W reduces oxidative stress, nitrosative stress, and/or proinflammatory cytokines while also directly suppressing the activity of iNOS (Massey et al, 2023;Méndez-Valdés et al, 2023;Putra et al, 2020;Tsai & Lein, 2021). Conversely, tempol may only be exerting an antioxidant effect with no direct action on iNOS.…”

“…Data from our lab, and others, have shown reduced cutaneous vascular responses to local heating in non-Hispanic Black young adults (Akins et al, 2022;Hurr et al, 2018;Kim et al, 2018;Kim & Brothers, 2020;Miller et al, 2021;Patik et al, 2018;Turner et al, 2020;Turner, Hayat, et al, 2023;Wolf et al, 2020;Wong et al, 2020). We recently demonstrated this reduction is due, in part, to activity of inducible NO synthase (iNOS), which is upregulated under stress conditions, such as increased levels of superoxide, and has been shown to contribute to reduced cutaneous NO-dependent vasodilation in hypertensive humans (Massey et al, 2023;Miller et al, 2021;Putra et al, 2020;Smith et al, 2011;Tsai & Lein, 2021). Previous data also indicates inhibition of superoxide and oxidative stress can improve NO-dependent vasodilation in non-Hispanic Black young adults (Hurr et al, 2018;Kim & Brothers, 2020;Patik et al, 2018;Turner, Hayat, et al, 2023;Wolf et al, 2020).…”

“…Previous data also indicates inhibition of superoxide and oxidative stress can improve NO-dependent vasodilation in non-Hispanic Black young adults (Hurr et al, 2018;Kim & Brothers, 2020;Patik et al, 2018;Turner, Hayat, et al, 2023;Wolf et al, 2020). Data in animal models suggests the iNOS inhibitor 1400 W may also attenuate oxidative stress, nitrosative stress, and proinflammatory cytokines in addition to its direct effects on iNOS (Massey et al, 2023;Putra et al, 2020). Although there is a close relationship between superoxide and iNOS activity, superoxide represents only one specific form of oxidative stress and other reactive oxygen species could also increase activity of iNOS.…”

Disease-Modifying Effects of a Glial-targeted Inducible Nitric Oxide Synthase Inhibitor (1400W) in Mixed-sex Cohorts of a Rat Soman (GD) Model of Epilepsy

“…Our previous study demonstrated a signi cant increase in the inducible nitric oxide synthase (iNOS) in the brains of OPNA exposed adult rats, which persisted for long-term in glial cells [14]. Treatment with a highly selective iNOS inhibitor, 1400W hydrochloride, suppressed serum nitrite production and also reduced iNOS levels in the brain [14,15]. In addition, we found a signi cant increase in neuronal nitric oxide synthase (nNOS) post-SE, but unlike iNOS, it was only transiently upregulated [16,17].…”