Delay of photoreceptor degeneration in tubby mouse by sulforaphane.
In this study, the homozygous tubby (tub/tub) mutant mouse, with an early progressive hearing loss and photoreceptor degeneration, was used as a model system to examine the effects of systemic administration of a naturally occurring isothiocyanate, sulforaphane (SF), on photoreceptor degeneration. Several novel observations have been made: (i) the mRNA and protein expression of thioredoxin (Trx), thioredoxin reductase (TrxR) and NF-E2-related factor-2 (Nrf2) were significantly reduced even prior to photoreceptor cell degeneration in the retinas of tub/tub mice, suggesting that retinal expression of the Trx system is impaired and that Trx regulation is involved in the pathogenesis of retinal degeneration in this model, (ii) intraperitoneal injection with SF significantly up-regulated retinal levels of Trx, TrxR, and Nrf2, and effectively protected photoreceptor cells in tub/tub mice as evaluated functionally by electroretinography and morphologically by quantitative histology, and (iii) treatment with PD98059, an inhibitor of extracellular signal-regulated kinases (ERKs), blocked SF-mediated ERKs activation and up-regulation of Trx/TrxR/Nrf2 in the retinas of tub/tub mice. This suggests that ERKs and Nrf2 are involved in the mechanism of SF-mediated up-regulation of the Trx system to protect photoreceptor cells in this model. These novel findings are significant and could provide important information for the development of a unique strategy to prevent sensorineural deafness/retinal dystrophic syndromes and also other forms of inherited neurological disorders.
Kong
Li
L
Department of Ophthalmology and Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Tanito
Masaki
M
Huang
Zhong
Z
Li
Feng
F
Zhou
Xiaohong
X
Zaharia
Alexander
A
Yodoi
Junkie
J
McGinnis
James F
JF
Cao
Wei
W
D048868:Adaptor Proteins, Signal Transducing; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D004195:Disease Models, Animal; D004596:Electroretinography; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D017879:Isothiocyanates; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008954:Models, Biological; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D010786:Photoreceptor Cells / Q000187:drug effects*; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D012162:Retinal Degeneration / Q000235:genetics / Q000473:pathology* / Q000517:prevention & control*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013454:Sulfoxides; D013861:Thiocyanates / Q000008:administration & dosage*; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D004791:Enzyme Inhibitors; D005419:Flavonoids; D017879:Isothiocyanates; D051267:NF-E2-Related Factor 2; D011506:Proteins; D012333:RNA, Messenger; D013454:Sulfoxides; D013861:Thiocyanates; C098988:Tub protein, mouse; D013879:Thioredoxins; D013880:Thioredoxin-Disulfide Reductase; D048049:Extracellular Signal-Regulated MAP Kinases; C016766:sulforaphane; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one