Telomere elongation in the gut extends systemic healthspan of zebrafish

Telomere shortening is a hallmark of aging and is counteracted by telomerase. zebrafish gut is one of the organs with the fastest rate of telomere decline. However, whether telomere-dependent aging of an individual organ, the gut, causes systemic aging remains unknown. Here, we show that preventing telomere shortening in the gut through tissue-specific telomerase expression rescues premature aging of tert-/-. Conclusively, we show that gut-specific telomerase expression extends lifespan of tert-/- by 40 %, while ameliorating natural aging. Our work demonstrates that delaying telomere shortening in the gut is sufficient to systemically counteract aging in zebrafish.