Inhibition of NADPH oxidase activation reduces EAE-induced white matter damage in mice

Abstract

BackgroundTo evaluate the role of NADPH oxidase-mediated reactive oxygen species (ROS) production in multiple sclerosis pathogenesis, we examined the effects of apocynin, an NADPH oxidase assembly inhibitor, on experimental autoimmune encephalomyelitis (EAE).MethodsEAE was induced by immunization with myelin oligodendrocyte glycoprotein (MOG (35-55)) in C57BL/6 female mice. Three weeks after initial immunization, the mice were analyzed for demyelination, immune cell infiltration, and ROS production. Apocynin (30 mg/kg) was given orally once daily for the entire experimental course or after the typical onset of clinical symptom (15 days after first MOG injection).ResultsClinical signs of EAE first appeared on day 11 and reached a peak level on day 19 after the initial immunization. The daily clinical symptoms of EAE mice were profoundly reduced by apocynin. The apocynin-mediated inhibition of the clinical course of EAE was accompanied by suppression of demyelination, reduced infiltration by encephalitogenic immune cells including CD4, CD8, CD20, and F4/80-positive cells. Apocynin reduced MOG-induced pro-inflammatory cytokines in cultured microglia. Apocynin also remarkably inhibited EAE-associated ROS production and blood–brain barrier (BBB) disruption. Furthermore, the present study found that post-treatment with apocynin also reduced the clinical course of EAE and spinal cord demyelination.ConclusionsThese results demonstrate that apocynin inhibits the clinical features and neuropathological changes associated with EAE. Therefore, the present study suggests that inhibition of NADPH oxidase activation by apocynin may have a high therapeutic potential for treatment of multiple sclerosis pathogenesis.

Nimodipine fosters remyelination in a mouse model of multiple sclerosis and induces microglia-specific apoptosis

“…Most recently Nox4 and Cpt1a expression was linked to the activation of the inflammasome in macrophages (38). Furthermore, inhibition of NADPH oxidase activation in EAE mice was associated with reduced histopathology, partially via reducing NADPH oxidasemediated ROS production (28). Indeed, nimodipine treatment decreased the levels of NO, iNOS, and ROS in the CNS.…”

“…The spinal cord was transversally cut with a Leica cryostat into 10-μm-thick sections for fluorescence microscopic analyses and into 30-μm-thick sections for confocal analyses and were counterstained with DAPI (1:2,000 in PBS). The protocol was adapted from Choi et al (28).…”

“…Because iNOS expression levels were low in EAE lesions, it was impossible to show lesion-specific effects in quantitative RT-PCR (RT-qPCR) analyses of the spinal cord. Instead we chose to investigate ROS, which are strongly produced in EAE lesions, using the dihydroethidium (dHet) detection method (28). The data demonstrate significantly reduced levels of ROS in both funiculi of the spinal cord after treatment with nimodipine ( Fig.…”

White matter damage after traumatic brain injury: A role for damage associated molecular patterns

“…Oligodendrocytes are extremely susceptible to oxidative damage due to a high metabolic rate [183, 184]. Although a functional association between microglial NADPH oxidase activity and white matter loss remains undetermined after TBI, NADPH oxidase is expressed in microglia and infiltrating macrophages in active multiple sclerosis lesions and NADPH oxidase activity is associated with demyelination, white matter damage, and tissue loss after EAE in mice [185, 186]. Importantly, activation of microglial TLR4 induced pre-oligodendrocyte injury via a NADPH oxidase mediated mechanism in a neonatal rat model of periventricular leukomalacia, which is characterized by white matter loss around the cerebral ventricles [187].…”

Febuxostat ameliorates secondary progressive experimental autoimmune encephalomyelitis by restoring mitochondrial energy production in a GOT2-dependent manner

“…We and others have reported the utility of ROS inhibitors in animal models of neurodegenerative disease, including in EAE [11,30,31]. Although the mechanism by which febuxostat promotes GOT2 expression and improves mitochondrial function remains unknown, previous report showed nuclear genes encoding mitochondrial protein including GOT2 is downregulated under hypoxic state [32].…”