Effect of Geranylgeranylacetone on Ultraviolet Radiation Type B-Induced Cataract in Heat-Shock Transcription Factor 1 Heterozygous Mouse.
PURPOSE
We investigated whether heat-shock transcription factor 1 (HSF1) was involved in ultraviolet radiation type B (UVR-B)-induced lens opacity (cataract) using HSF1 heterozygous mice. We also examined the effects of geranylgeranylacetone (GGA), an inducer of heat-shock proteins via activation of HSF, on the UVR-B-induced cataract.


MATERIAL AND METHODS
Male HSF1+/- and WT mice were unilaterally exposed to UVR-B (total: 1200mJ) at 16 weeks of age. At 48 h after the last UVR-B irradiation, the lens was isolated and the induction of the cataract was quantified as the cataract area ratio (opacity area/anterior capsule). GGA was orally administered at a dosage of 500 mg/kg once a day for two days before the first UVR-B exposure until the end of the experiment (21days in total).


RESULTS
The HSF1 expression was more greatly decreased in the lens from HSF1+/- mice than in that from WT mice (p < 0.01). UVR-B exposure could mainly induce cataracts in the anterior capsule in both HSF1+/- and WT mice, while the opacity of the lens was markedly enhanced in HSF1+/- mice compared to that in WT mice(p (0.01). GGA treatment could prevent the induction of lens opacity by UVR-B exposure in both WT and HSF1+/- mice as compared with the non-administration group (p < 0.01). No obvious alteration by the UVR-B radiation was seen in lens protein levels of αA-crystallin, αB-crystallin, or γ-crystallin with or without GGA administration among all groups of mice. In contrast to the crystallins, the lens protein level of HSP25 was decreased by UVR-B exposure in both HSF1+/- and WT mice, and was significantly recovered in WT mice by the GGA treatment (p < 0.01). The induction of HSP25 was suppressed in HSF1+/- mice compared with that in WT mice.


CONCLUSIONS
These data suggest that HSF1 plays an important role in the occurrence of UVR-B-induced cataracts, possibly via regulation of HSPs such as HSP25.
['Ogasawara|Satoshi|S|', 'Hashizume|Kouhei|K|', 'Okuno|Takashi|T|', 'Imaizumi|Toshiyasu|T|', 'Inomata|Yui|Y|', 'Tezuka|Yu|Y|', 'Sanbe|Atushi|A|', 'Kurosaka|Daijiro|D|']
D000818:Animals D015153:Blotting, Western D002386:Cataract D004252:DNA Mutational Analysis D004224:Diterpenes D004307:Dose-Response Relationship, Radiation D005260:Female D005786:Gene Expression Regulation D000076249:Heat Shock Transcription Factors D006579:Heterozygote D007908:Lens, Crystalline D008297:Male D051379:Mice D008810:Mice, Inbred C57BL D008822:Mice, Transgenic D012313:RNA D011833:Radiation Injuries, Experimental D060888:Real-Time Polymerase Chain Reaction D014157:Transcription Factors D014466:Ultraviolet Rays
geranylgeranylacetone Cataract ultraviolet radiation type B heat-shock proteins heat-shock protein transcription factor 1