The RNA world of human ageing.

Ageing is one of the most complex processes in nature; how could we prevent the associated biological changes and chronic diseases that string along with this process, is a challenge in healthcare around the world. Recent advances in next-generation sequencing have reached a stage where it is possible to know from a specific tissue the most abundant transcripts, alternative splicing process and, non-coding RNA molecules (microRNA's, long non-coding RNA's, and circular RNAs). Moreover, our knowledge of several biological processes related to ageing such as senescence and autophagy have dramatically increased in the last years. In the present review, we attempt to summarise the latest scientific advances from the most critical studies performed in human clinical samples, specific to the RNA studies about ageing. Overall, human transcriptomics research indicates that although there are common alterations of the regular expression patterns of the energetic and oxidative metabolism, extracellular matrix regulation and inflammation pathways, ageing seems to be gender and tissue-specific in general. Additionally, there is an age-related implication in several numbers of impaired events on the normal alternative splicing process. On the other hand, there is a direct relation of several non-coding RNA molecules with age-related changes which indicates its possible use as biomarkers for diagnostics and therapeutically purposes. Together, these findings highlight the importance to continue focusing research on RNA studies to improve our knowledge in the pathophysiology of age-related diseases.