Aging is the primary cause of chronic human morbidity and mortality. Interventions targeting key proteins that extend healthy lifespan at the cellular and organismal level are therefore desirable. Genetic changes that extend lifespan in model organisms often delay the onset of age-related morbidity and exhibit evolutionary conservation in higher organisms. Cells typically use gene networks to coordinate their response to stimuli, and thus the dynamics of cellular aging is also likely governed at the gene network level. However, little is known about the composition of such an aging network both in terms of the genes involved and their relationship within the network. By performing high-throughput measurements of yeast replicative lifespan in a microfluidic device, this proposal aims to identify and functionally compartmentalize the genetic components of novel aging modules based on the strength of epistatic interactions. Furthermore, it aims to elucidate the impact of these network modules on noise reduction during aging, an emergent property of single-cell aging. Key components of the aging modules as well as genes from a chromatin-remodeling network will be deleted from the yeast genome and the resulting changes in genetic noise dynamics will be measured using the activity of the canonical GAL1 promoter as a model in single yeast cells. Finally, expression strength changes of the key genes composing the aging modules will be followed experimentally during cellular aging with the goal of exploring how aging alters the plasticity of network nodes. Successful completion of this project will provide novel links between replicative lifespan and the collective phenotype of gene expression noise in the context of newly identified network modules governing how single yeast cells age in real time.
Applying a quantitative network construction algorithm on replicative lifespan data collected from live yeast cells in microfluidic environments, this proposal aims to construct aging modules governing the aging and noise dynamics of single cells. Due to the conserved nature of many genetic and cell biological processes between yeast and higher eukaryotes, we expect our results will shed light on the composition of the aging network in human cells.!
| Song, Ruijie; Sarnoski, Ethan A; Acar, Murat (2018) The Systems Biology of Single-Cell Aging. iScience 7:154-169 |
