Raman microscopy and isolation of aged yeast cells to investigate cellular lipid changes in aging

Abstract

Life expectancy increased to about 80 years, but advanced age is still a risk to human beings. To deal with this risk, many studies worked on the mechanisms behind aging and senescence and relevant diseases. Aging refers to organism-wide functional decline, senescence occurs at the level of individual cells entering permanent cell-cycle arrest.

Accumulations of senescent cells are linked to metabolic imbalances, neurodegenerative diseases, and other age-associated disorders, with the dysregulation of lipid metabolism playing a particularly important role. Lipids serve structural functions in cellular membranes and act as key mediators in signaling, transport, and metabolic pathways. During aging, these lipids can accumulate oxidative damage and peroxidation by-products, contributing to chronic inflammation and organ dysfunction. Understanding lipids behavior might contribute to the knowledge of aging progress.

This dissertation focuses on two main objectives. First, utilize Raman Microscopy to mapping and monitor intracellular lipids as it is examined as a powerful, non-invasive tool to characterize molecules.

Second, budding yeast (Saccharomyces cerevisiae) is employed as a tractable model to investigate mechanisms of cellular aging, particularly the isolation of older cells that display key senescence markers. By combining Raman spectrometric analysis with refined yeast isolation strategies, this work aims to deepen our understanding of how lipid disruptions intersect with aging. The hypotheses guiding these studies are that (1) Raman-based mapping can reveal dynamic lipid changes within individual cells over time, and (2) it is feasible to isolate old yeast cells of different replicative ages to investigate the lipidome’s role in senescence. However, the results show that there is a limit for lipid real-time mapping, and the yield of isolated old budding yeast cells by magnetic sorting is low, and some optimization might increase the yield. Ultimately, the results and discussion offer new perspectives in optimizing lipid mapping by Ramam Microscopy and the isolation of aged budding yeast cells.