The wonderful new world of telomerase in the brain and its possible implications for neurodegenerative diseases

While telomerase is best known as the enzyme that maintains telomeres in dividing cells a number of TERT (Telomerase Reverse Transcriptase)-related non-canonical functions have been described. These functions are implicated in tumour development and stress response and recently have also been demonstrated in the brain. In contrast to other cells and tissues, in the brain the telomerase RNA component TERC is downregulated early during development resulting in the loss of telomerase activity in most cells except for neural stem cells. In contrast, the presence of the telomerase protein TERT persists during lifetime in neurons of the human brain. Although we are far from understanding the role of telomerase in the brain, the review aims to summarise our current knowledge. In addition to physiological functions in healthy neurons, there might be implications for neurodegenerative diseases.