Contributions
Abstract: P429
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 13 Experimental models
Background: Oxidative stress and mitochondrial dysfunction are important determinants of axonal degeneration in secondary progressive multiple sclerosis (SPMS). We previously showed that febuxostat, a xanthine oxidase inhibitor, ameliorated both relapsing-remitting and secondary progressive experimental autoimmune encephalomyelitis (EAE) by preventing axonal loss in mice. In this study, we investigated how febuxostat preserves axons in secondary progressive EAE.
Methods and Results: A DNA microarray analysis revealed that febuxostat treatment increased the CNS expression of several mitochondria-related genes in EAE mice, most notably including GOT2, which encodes glutamate oxaloacetate transaminase 2 (GOT2). GOT2 is a mitochondrial enzyme that oxidizes glutamate to produce α-ketoglutarate for the Krebs cycle, eventually leading to the production of adenosine triphosphate (ATP). Whereas GOT2 expression was decreased in the spinal cord during the chronic progressive phase of EAE, febuxostat-treated EAE mice showed increased GOT2 expression. A detailed morphological assessment of GOT2 distribution suggested that GOT2 was predominantly expressed in neuronal somata within gray matter of the spinal cord. Double immunofluorescence staining of GOT2 with neuronal marker Microtuble Associated Proteins 2 (MAP2) and mitochondrial marker TOM20 demonstrated that GOT2 was predominantly expressed in neuronal mitochondria. Reflecting the ability of febuxostat to rescue mitochondrial dysfunction in neurons, febuxostat treatment of Neuro2a cells in vitro ameliorated ATP exhaustion induced by rotenone application. By contrast, febuxostat alone did not affect steady-state ATP levels. The ability of febuxostat to preserve ATP production in the presence of rotenone was significantly reduced by GOT2 siRNA.
Conclusions: GOT2-mediated ATP synthesis may be a pivotal mechanism underlying the protective effect of febuxostat against axonal damage in EAE. Accordingly, febuxostat may also have clinical utility as a disease-modifying drug in SPMS.
Disclosure: Makoto Kinoshita:nothing to disclose, Josephe A. Honorat:nothing to disclose, Tatsusada Okuno:nothing to disclose, Yuji Nakatsuji:nothing to disclose, Mikito Shimizu:nothing to disclose, Akiko Namba:nothing to disclose, Kazuya Yamashita:nothing to disclose, Takashi Shirakura:nothing to disclose, Hideki Mochizuki:nothing to disclose
Abstract: P429
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 13 Experimental models
Background: Oxidative stress and mitochondrial dysfunction are important determinants of axonal degeneration in secondary progressive multiple sclerosis (SPMS). We previously showed that febuxostat, a xanthine oxidase inhibitor, ameliorated both relapsing-remitting and secondary progressive experimental autoimmune encephalomyelitis (EAE) by preventing axonal loss in mice. In this study, we investigated how febuxostat preserves axons in secondary progressive EAE.
Methods and Results: A DNA microarray analysis revealed that febuxostat treatment increased the CNS expression of several mitochondria-related genes in EAE mice, most notably including GOT2, which encodes glutamate oxaloacetate transaminase 2 (GOT2). GOT2 is a mitochondrial enzyme that oxidizes glutamate to produce α-ketoglutarate for the Krebs cycle, eventually leading to the production of adenosine triphosphate (ATP). Whereas GOT2 expression was decreased in the spinal cord during the chronic progressive phase of EAE, febuxostat-treated EAE mice showed increased GOT2 expression. A detailed morphological assessment of GOT2 distribution suggested that GOT2 was predominantly expressed in neuronal somata within gray matter of the spinal cord. Double immunofluorescence staining of GOT2 with neuronal marker Microtuble Associated Proteins 2 (MAP2) and mitochondrial marker TOM20 demonstrated that GOT2 was predominantly expressed in neuronal mitochondria. Reflecting the ability of febuxostat to rescue mitochondrial dysfunction in neurons, febuxostat treatment of Neuro2a cells in vitro ameliorated ATP exhaustion induced by rotenone application. By contrast, febuxostat alone did not affect steady-state ATP levels. The ability of febuxostat to preserve ATP production in the presence of rotenone was significantly reduced by GOT2 siRNA.
Conclusions: GOT2-mediated ATP synthesis may be a pivotal mechanism underlying the protective effect of febuxostat against axonal damage in EAE. Accordingly, febuxostat may also have clinical utility as a disease-modifying drug in SPMS.
Disclosure: Makoto Kinoshita:nothing to disclose, Josephe A. Honorat:nothing to disclose, Tatsusada Okuno:nothing to disclose, Yuji Nakatsuji:nothing to disclose, Mikito Shimizu:nothing to disclose, Akiko Namba:nothing to disclose, Kazuya Yamashita:nothing to disclose, Takashi Shirakura:nothing to disclose, Hideki Mochizuki:nothing to disclose