Axonal and Cell Body Protection By Nicotinamide Adenine Dinucleotide in Tumor Necrosis Factor-Induced Optic Neuropathy

• Published in: Journal of neuropathology and experimental neurology 2009-08, Vol.68 (8), p.915-927
• Main Authors: Kitaoka, Yasushi, Hayashi, Yasuhiro, Kumai, Toshio, Takeda, Hiroyuki, Munemasa, Yasunari, Fujino, Hiromi, Kitaoka, Yuka, Ueno, Satoki, Sadun, Alfredo A, Lam, Tim T
• Format: Article
• Language: English
• Subjects: Animals; Axons - drug effects; Axons - pathology; Axons - ultrastructure; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; Cranial nerves. Spinal roots. Peripheral nerves. Autonomic nervous system. Gustation. Olfaction; Disease Models, Animal; Gene Expression Regulation, Enzymologic - drug effects; Male; Medical sciences; Microscopy, Electron, Transmission - methods; NAD - genetics; NAD - pharmacology; Nerve Tissue Proteins - metabolism; Nervous system (semeiology, syndromes); Neurology; Nicotinamide-Nucleotide Adenylyltransferase - genetics; Nicotinamide-Nucleotide Adenylyltransferase - metabolism; Optic Nerve Diseases - chemically induced; Optic Nerve Diseases - pathology; Rats; Rats, Wistar; Retinal Ganglion Cells - drug effects; Retinal Ganglion Cells - pathology; RNA, Messenger - metabolism; Statistics, Nonparametric; Stilbamidines; Time Factors; Tumor Necrosis Factor-alpha
• ISSN: 0022-3069; 1554-6578
• DOI: 10.1097/NEN.0b013e3181afecfa

Axonal degeneration often leads to the death of neuronal cell bodies. Previous studies have demonstrated the crucial role of nicotinamide adenine dinucleotide (NAD) biosynthesis in axonal protection of motor neurons, but the role of nicotinamide mononucleotide adenylyltransferase 1 and NAD in optic nerve degeneration is unclear. Intravitreal injection of tumor necrosis factor (TNF) induces optic nerve degeneration and subsequent loss of retinal ganglion cells. We found that the levels of nicotinamide mononucleotide adenylyltransferase 1 mRNA and protein and of NAD were significantly decreased in the optic nerve after intravitreal injection of TNF in rats. The concomitant disorganization of microtubules with vacuoles and neurofilament accumulations in the axons were blocked by exogenous NAD treatment. Nicotinamide adenine dinucleotide also prevented TNF-induced axonal loss and delayed retinal ganglion cell loss 2 months after TNF injection. Microglia identified by immunohistochemistry were increased in the optic nerves after TNF injection; this increase was inhibited by NAD treatment. These results suggest that axonal nicotinamide mononucleotide adenylyltransferase 1 and NAD declines are associated with TNF-induced optic nerve axonal degeneration and that axonal protection of NAD may be related to its inhibitory effect on microglial activation.