Quantitative identification of senescent cells in aging and disease

Senescent cells are present in premalignant lesions and sites of tissue damage and accumulate in tissues with age. In vivo identification, quantification and characterization of senescent cells are challenging tasks that limit our understanding of the role of senescent cells in diseases and aging. Here, we present a new way to precisely quantify and identify senescent cells in tissues on a single‐cell basis. The method combines a senescence‐associated beta‐galactosidase assay with staining of molecular markers for cellular senescence and of cellular identity. By utilizing technology that combines flow cytometry with high‐content image analysis, we were able to quantify senescent cells in tumors, fibrotic tissues, and tissues of aged mice. Our approach also yielded the finding that senescent cells in tissues of aged mice are larger than nonsenescent cells. Thus, this method provides a basis for quantitative assessment of senescent cells and it offers proof of principle for combination of different markers of senescence. It paves the way for screening of senescent cells for identification of new senescence biomarkers, genes that bypass senescence or senolytic compounds that eliminate senescent cells, thus enabling a deeper understanding of the senescent state in vivo.     

Co-regulation of polar mRNA transport and lifespan in budding yeast Saccharomyces cerevisiae

Recent studies have uncovered the links between aging, rejuvenation and polar protein transport in the budding yeast Saccharomyces cerevisiae. Here, we examined a still unexplored possibility for co-regulation of polar mRNA transport and lifespan. To monitor the amount and distribution of mRNA-containing granules in mother and daughter cells, we used a fluorescent mRNA-labeling system, with MFA2 as a reporter gene. The results obtained showed that deletion of the selected longevity regulators in budding yeast had a significant impact on the polar mRNA transport. This included changes in the amount of mRNA-containing granules in cytoplasm, their aggregation and distribution between the mother and daughter cells. A significant negative correlation was found between strain-specific longevity, amount of granules and total fluorescent intensity both in mother and daughter cells. As indicated by the coefficient of determination, approximately 50–75% of variation in yeast lifespan could be attributed to the differences in polar mRNA transport.     

Co-regulation of polar mRNA transport and lifespan in budding yeast Saccharomyces cerevisiae

Recent studies have uncovered the links between aging, rejuvenation and polar protein transport in the budding yeast Saccharomyces cerevisiae. Here, we examined a still unexplored possibility for co-regulation of polar mRNA transport and lifespan. To monitor the amount and distribution of mRNA-containing granules in mother and daughter cells, we used a fluorescent mRNA-labeling system, with MFA2 as a reporter gene. The results obtained showed that deletion of the selected longevity regulators in budding yeast had a significant impact on the polar mRNA transport. This included changes in the amount of mRNA-containing granules in cytoplasm, their aggregation and distribution between the mother and daughter cells. A significant negative correlation was found between strain-specific longevity, amount of granules and total fluorescent intensity both in mother and daughter cells. As indicated by the coefficient of determination, approximately 50–75% of variation in yeast lifespan could be attributed to the differences in polar mRNA transport.