Interleukin-1 attenuates normal tension glaucoma-like retinal degeneration in EAAC1-deficient mice.
Glaucoma, one of the leading causes of irreversible blindness, is characterized by progressive degeneration of retinal ganglion cells (RGCs) and optic nerves. Although glaucoma is often associated with elevated intraocular pressure, recent studies have shown a relatively high prevalence of normal tension glaucoma (NTG) in glaucoma patient populations. In the mammalian retina, glutamate/aspartate transporter (GLAST) is localized to Müller glial cells, whereas excitatory amino acid carrier 1 (EAAC1) is expressed in neural cells, including RGCs. Since the loss of GLAST or EAAC1 leads to retinal degeneration similar to that seen in NTG, we examined the effects of interleukin-1 (IL-1) on RGC death in GLAST- and EAAC1-deficient mice. IL-1 promoted increased glutamate uptake in Müller cells by suppressing intracellular Na(+) accumulation, which is necessary to counteract Na(+)-glutamate cotransport. The observed trends for the glutamate uptake increase in the wild-type (WT), GLAST- and EAAC1-deficient mice were similar; however, the baseline glutamate uptake and intracellular Na(+) concentration in the GLAST-deficient mice were significantly lower than those in the wild-type mice. Consistently, pretreatment with IL-1 exhibited no beneficial effects on glutamate-induced RGC degeneration in the GLAST-deficient mice. In contrast, IL-1 significantly increased glutamate uptake by Müller cells and the number of surviving RGCs in the wild-type and EAAC1-deficient mice. Our findings suggest that the use of IL-1 for enhancing the function of glutamate transporters may be useful for neuroprotection in retinal degenerative disorders including NTG.
Namekata
Kazuhiko
K
Department of Molecular Neurobiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526, Japan.
Harada
Chikako
C
Guo
Xiaoli
X
Kikushima
Kenji
K
Kimura
Atsuko
A
Fuse
Nobuo
N
Mitamura
Yoshinori
Y
Kohyama
Kuniko
K
Matsumoto
Yoh
Y
Tanaka
Kohichi
K
Harada
Takayuki
T
D000818:Animals; D016923:Cell Death / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D027341:Excitatory Amino Acid Transporter 1 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D050580:Excitatory Amino Acid Transporter 3 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D005901:Glaucoma / Q000503:physiopathology; D018698:Glutamic Acid / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism*; D042541:Intracellular Space / Q000378:metabolism; D007429:Intraocular Pressure; D051379:Mice; D018345:Mice, Knockout; D009457:Neuroglia / Q000502:physiology; D012160:Retina / Q000503:physiopathology*; D012162:Retinal Degeneration / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000502:physiology*; D012964:Sodium / Q000378:metabolism
D027341:Excitatory Amino Acid Transporter 1; D050580:Excitatory Amino Acid Transporter 3; D007375:Interleukin-1; C493399:Slc1a1 protein, mouse; C493393:Slc1a3 protein, mouse; D018698:Glutamic Acid; D012964:Sodium