Long non-coding RNAs transcribed from telomeres, known as TERRA (telomeric repeat-containing RNA), are associated with telomere and genome stability. TERRA abundance responds to different cell stresses; however, no studies have focused on oxidative stress, condition that damages biomolecules and is involved in aging and disease. Since telomeres are prone to oxidative damage leading to their dysfunction, our objective was to characterize TERRAs and the mechanisms that control their expression. TERRA increased in cells exposed to H2O2 and reverted by antioxidant treatment. TERRAs are also induced in brown adipose tissue of mice exposed to cold, which raises mitochondrial ROS. In cells exposed to H2O2, ChIP showed that chromatin landscape was modified favoring telomere transcription. TERRAs interacted with HP1α/γ, proteins that were found recruited to subtelomeres. Since HP1γ interacts with the transcriptional machinery, TERRAs may stimulate their own expression by recruiting HP1γ to subtelomeres. TERRA induction reverted within 2 h after removal of H2O2 from culture medium, suggesting they have protective functions. This was supported by rapid TERRA induction following a second H2O2 challenge. PKA inhibitors H89 and PKI blocked TERRA increase by H2O2 or IBMX+Forskolin treatment, suggesting PKA signaling regulates TERRA induction. Treatment of cells with drugs that disturb cytoskeleton integrity or growing cells on surfaces of different stiffness known to generate differential cytoskeleton tension also modified TERRA levels and sensitized cells to lower H2O2 concentrations. In summary, we show that TERRAs are induced in response to oxidative stress and are regulated by PKA as well as by changes in cytoskeleton dynamics.
Keywords: Cytoskeleton dynamics; Oxidative stress; PKA; TERRA; Telomere dysfunction; Transcriptional memory.
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