Characterization of the antioxidant systems in different complementation groups of Dyskeratosis Congenita.

Abstract

The telomerase complex and Telosome regulate, maintenance and repair telomeres. The telomerase complex is formed by complex of protein (TERT, Dyskerin, GAR, NHP2, NOP10) and nucleic acid (TERC) that together work as a reverse transcriptase. The Telosoma comprises a network of protein (TRF2, TRF1, TIN2, RAP1, TPP1 and POT1). Furthermore, dyskeratosis congenita (DC) (ORPHA1775) is a rare disease with similar characteristics to premature aging. DC is a genetically heterogeneous disease caused by mutations in the genes that encoding for different subunits of the telomerase complex and Telosome. It is known that the telomeric DNA is susceptible to oxidative stress, and telomerase activity dependent cellular redox environment. Recently a correlation between telomerase activity and catalase activity was established, and it has suggested a role of antioxidant extranuclear telomerase. However, it is not yet clear whether there is any relationship or connection between molecular telomerase activity and cellular antioxidant defense. In this paper, by using the technology of RNA interference (siRNA) silencing DKC1, NOP10 genes of telomerase complex and TINF2 of Telosoma in HeLa cells, on cellular antioxidant capacity will be presented. It was intended to see if there is a cellular effect related to the production of oxidative stress or alteration of antioxidant systems after silencing these components involved in telomere maintenance. In this paper we have evaluated the levels of DKC1, NOP10, TINF2 levels of antioxidant enzymes (CuZnSOD, MnSOD, Catalase, Gpx1, Grx1 and Trx1) by RT- qPCR and Western blotting. We analyzed the production of reactive oxygen species by fluorimetry and also assessed the activity of the telomerase complex by Sybr Green RT- QTrap.