Thioredoxins 1 and 2 are neuroprotective in retinal ganglion cells after optic nerve transection and oxidative stress
Yasunari Munemasa 1,
Seok Hwan Kim 1,
Jae Hong Ahn 2,
Jacky M.K. Kwong 3,
Joseph Caprioli 1,
and
Natik Piri 2*
1 Jules Stein Eye Institute, UCLA, Los Angeles, California, United States
2 Ophthalmology, UCLA, Los Angeles, California, United States
3 Dept. of Ophthalmology, Jules Stein Eye Institute, Los Angeles, California, United States
* To whom correspondence should be addressed. E-mail: piri{at}jsei.ucla.edu.
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Abstract |
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Purpose. Oxidative stress has been implicated in retinal ganglion cell (RGCs) death pathways after optic nerve transection (ONT) and during glaucomatous neuropathy. In this study, we investigated the expression and cell protective roles of thioredoxins (cytosolic Trx1 and mitochondrial Trx2), important regulators of the cellular redox state, on RGCs after ONT and pharmacological oxidative stress induction.
Methods. ONT was performed on adult Wistar rats. Trx1 and Trx2 quantitative and spatial expression were examined with western blot and immunohistochemisty, respectively. Electroporation and calcium phosphate-mediated procedure were used to deliver Trx1 and Trx2 expression constructs to RGCs in vivo and to cultured RGC-5 cells, respectively. Cell protective effect of Trx1 and Trx2 overexpression on RGCs after ONT and on RGC-5 cells treated with glutamate/buthionine sulfoximine (BSO) was determined by RGCs density analysis and cell viability assay, respectively.
Results. Upregulation of both Trx1 and Trx2 was observed in RGCs at different times after ONT and in RGC-5 cells after glutamate/BSO treatment. Trx1 and Trx2 overexpression in RGC-5 cells increased their survival rate by approximately two and three fold 24 and 48 hours after glutamate/BSO treatment, respectively. A neuroprotective effect of Trx1 and Trx2 overexpression on RGCs was also observed in vivo; the survival rate of RGCs was increased by 35% and 135% one and two weeks after ONT, respectively.
Conclusion. These findings provide evidence for in vitro and in vivo cell protective effects of Trx1 and Trx2 on RGCs against oxidative stress induced neurodegeneration.
Key Words:
ganglion cell, gene transfer, gene expression, optic nerve, oxidative damage
