GSE167665
Bulk RNA-seq of mice covering the whole lifespan (2 days to 904 days) from four tissues
Gene expression changes during ageing were shown to oppose developmental trajectories; a reversal pattern previously linked to cellular identity loss. Generating cortex, lung, liver and muscle tissue transcriptomes of 16 mice of different ages, covering development and ageing periods, we found that expression reversals were widespread but tissue-specific. Consistent with this result, we observed an inter-tissue divergence during development and convergence during ageing (DiCo), further confirmed in independent mouse and human datasets. The genes displaying DiCo pattern were enriched among tissue-specific genes that tended to lose developmental expression levels during ageing. Finally, analysing publicly available single-cell transcriptome data, we studied the contribution of cellular composition and cell-autonomous changes to the convergence in ageing. Our results, for the first time, suggest inter-tissue convergence during ageing is widespread and associated with the loss of specialisation at the tissue and possibly also at the cellular level. Overall design: Age-series mRNA expression profiles from 4 tissues (cerebral cortex, lung, liver, skeletal muscle) of 16 mice, covering postnatal development (2 days - 61 days) and ageing (93 days – 904 days) periods.