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Olga Krzysztynska-Kuleta, Mariusz Duda, Magdalena Olchawa, Tadeusz Jan Sarna; The effect of blue or violet light on the activation of melanopsin in transfected HEK-293T cells. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3094.
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Melanopsin, G-protein-coupled receptor is activated by short-wavelength visible light. Although in ipRGCs, melanopsin exhibits remarkable chemical and photochemical stability. The pigment can be photobleached with near-ultraviolet light. It is unknown that violet light could photobleached melanopsin and whereas products of the photobleaching exhibit significant any photoreactivity and phototoxicity. Here we examined the effect of blue or violet light irradiation on the activation of melanopsin in transfected HEK-293T cell line.
HEK-293T cells were transfected with plasmid pcDNA 3.1 coding hOPN4 using the calcium phosphate method. After transfection, cells were incubated with 11-cis retinal for 12 hours. Control cells and cells with added retinal were irradiated with 405nm or 485 nm light at sub-threshold doses for 0,5h, 1h and 1,5h. To expression of FOS or melanopsin, protein level were determined by Western blot assay. Additionally, Real Time PCR measurements were carried out to quantify of FOS and melanopsin mRNA the levels.
The expression of FOS and melanopsin protein increased in the transfected cells with irradiation time as observed in Western Blot assay. On the other hand, the effects of irradiation of melanopsin-expressing cells on FOS and melanopsin mRNA levels was different. In transfected cells irradiated with 485 nm light the level of mRNA FOS increased, whereas after exposure of this cells to 405light nm the level of FOS mRNA levels decreased. The amount of melanopsin mRNA in cells irradiated with 485 nm slightly higher whereas in cells irradiated with 405 nm the level of melanopsin mRNA was only significantly increased.
Our results confirmed that irradiation of transfected HEK-293T cells with 485 nm light activated melanopsin. It can be speculated that irradiation of melanopsin-expressing cells with 405 nm light may result in inactivation of melanopsin, leading subsequently to overproduction of melanopsin mRNA as a compensatory mechanism.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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