Project description:MicroRNAs (miRNAs) are endogenous small RNA molecules that regulate gene expression post-transcriptionally. Work in Caenorhabditis elegans has shown that specific miRNAs function in lifespan regulation and in a variety of age-associated pathways, but the roles of miRNAs in the aging of vertebrates are not well understood. We examined the expression of small RNAs in whole brains of young and old mice by deep sequencing and report here on the expression of 233 known miRNAs and identification of 41 novel miRNAs. Of these miRNAs, 75 known and 18 novel miRNAs exhibit greater than 2.0-fold expression changes. The majority of expressed miRNAs in our study decline in relative abundance in the aged brain, in agreement with trends observed in other miRNA studies in aging tissues and organisms. Target prediction analysis suggests that many of our novel aging-associated miRNAs target genes in the insulin signaling pathway, a central node of aging-associated genetic networks. These novel miRNAs may thereby regulate aging-related functions in the brain. Since mouse miRNAs are conserved in humans, the aging-affected brain miRNAs we report here may represent novel regulatory genes that function during aging in the human brain. 2 samples examined: Mouse brain from two young (5 months) and two old animals (24-25 months).
Project description:Aging is one of the main risk factors associated with the development of cancer. These two processes have been extensively investigated from the epigenetic perspective and consequently analogous epigenetic alterations have been identified for both, providing explanations on the possible molecular links between them. However, there is a need to study aging- and cancer-associated epigenetic patterns in a systematic manner to facilitate an integrated comparison between the two processes. In addition, it is essential to also confirm whether aging- and cancer-associated epigenetic alterations are equivalent in human and mouse models, as the latter are the main experimental proxy of human biology.In this study we sought to perform a systematic, integrated and intercomparable analysis of the DNA methylation dynamics associated to cancer and aging in both human and mouse. To this end, we profiled the brain methylomes of young and old, normal and tumoral brain samples from human and mouse by reduced-representation bisulfite sequencing (RRBS), which provided a robust and interspecies-comparable platform for these type of analyses. This data set only contains files involving human specimens. Accompanying mouse data can be downloaded from the ENA database under the accession number PRJEB41460.
Project description:An in-depth understanding of the molecular processes composing aging is crucial to develop therapeutic approaches that decrease aging as a key risk factor for cognitive decline. Herein, we present a spatio-temporal brain atlas (15 different regions) of microRNA expression across the mouse lifespan (7 time points) and two aging interventions. MicroRNAs are promising therapeutic targets, as they silence genes by complementary base-pair binding of messenger RNAs and mediate aging speed. We first established sex- and brain-region-specific microRNA expression patterns in young adult samples. Then we focused on sex-dependent and independent brain-region-specific microRNA expression changes during aging. We identified three sex-independent brain aging microRNAs (miR-146a-5p, miR-155-5p and miR-5100). For miR-155-5p, we showed that these expression changes are driven by aging microglia and target mTOR signaling pathway components and other cellular communication pathways. In this work, we identify strong sex-brain-region-specific aging microRNAs and microglial miR-155-5p as a promising therapeutic target.
Project description:An in-depth understanding of the molecular processes composing aging is crucial to develop therapeutic approaches that decrease aging as a key risk factor for cognitive decline. Herein, we present a spatio-temporal brain atlas (15 different regions) of microRNA expression across the mouse lifespan (7 time points) and two aging interventions. MicroRNAs are promising therapeutic targets, as they silence genes by complementary base-pair binding of messenger RNAs and mediate aging speed. We first established sex- and brain-region-specific microRNA expression patterns in young adult samples. Then we focused on sex-dependent and independent brain-region-specific microRNA expression changes during aging. We identified three sex-independent brain aging microRNAs (miR-146a-5p, miR-155-5p and miR-5100). For miR-155-5p, we showed that these expression changes are driven by aging microglia and target mTOR signaling pathway components and other cellular communication pathways. In this work, we identify strong sex-brain-region-specific aging microRNAs and microglial miR-155-5p as a promising therapeutic target.