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Abstract #47823 Published in IGR 13-4
Development of spontaneous neuropathy in NF-(kappa)Bp50-deficient mice by calcineurin-signal involving impaired NF-(kappa)B activation
Nakamura-Yanagidaira T; Takahashi Y; Sano K; Murata T; Hayashi TMolecular Vision 2011; 17: 2157-2170
Purpose: The transcriptional regulator, nuclear factor-kappa B (NF-(kappa)B)/Rel family are involved in neuronal cell death and survival. Previously, we reported that NF-(kappa)Bp50-deficient (p50-deficient) mice exhibit many features resembling human normal tension glaucoma (NTG). The developmental mechanism of human NTG is not clearly understood, and a radical curative treatment has yet to be established. Our aim is to elucidate the signal cascade which mediates the spontaneous optic neuropathy in p50-deficient mice as a model of NTG. Methods: To demonstrate the expression and activation of pro-apoptotic factors, which mediate the death of retinal ganglion cells (RGCs) in p50-deficient mice, western blot (WB) and luciferase reporter assays with retinas from p50- deficient and wild type mice, and cultured RGC-5 cells were performed. Furthermore, we tested the neuroprotective effects of chemical reagents (memantine, lomerizine, and tacrolimus) against N-methyl-D-aspartate (NMDA)-susceptible RGC damage according to in vitro experiments with RGC-5 cells. To elucidate the NF-(kappa)B-mediated death signaling, the effects of chemical reagents on spontaneous optic neuropathy were examined by histopathological studies. Results: WB experiments and luciferase reporter assays showed that NF-(kappa)B-inducible BCL2-associated X protein (Bax) and a pro-apoptotic factor, activated caspase 3 were expressed in the retina of p50-deficient mice as well as NMDA-treated RGC-5 cells. Further, the constitutivelyactivecleaved forms of calcineurin (CaN), which havebeen reported to lead to apoptosis, were detected in the retina of p50-deficient mice as well as NMDA-treated RGC-5 cells. Pre-treatment with tacrolimus markedlyprotected RGC-5 cells from NMDA-induced neurotoxicity, and then both spontaneous RGC death and degenerative changes to the optic nerve in p50-deficient mice were significantlyreduced by the chronic administration of tacrolimus. The experiments with cultured RGC-5 cells supported the results of histological examinations with p50- deficient mice, suggesting that CaN activation leads to NF-(kappa)B-induced Bax activation and caspase 3 activation, and mediates spontaneous optic neuropathy in p50-deficient mice. Conclusions: Research findings show that the chronic administration of tacrolimus significantly reduces spontaneous optic neuropathy in p50-deficient mice. We demonstrated a potential CaN signal cascade, which spontaneously induces age-dependent RGC death and degenerative optic nerve changes in p50-deficient mice. (copyright) 2011 Molecular Vision.
T. Hayashi. Department of Immunology and Infectious Disease, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan. Email: takumah@shinshu-u.ac.jp
Classification:
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
11.8 Neuroprotection (Part of: 11 Medical treatment)
