A budding yeast's perspective on aging: the shape I'm in

Role of Prohibitins in Aging and Therapeutic Potential Against Age-Related Diseases

A decline in mitochondrial function has long been associated with age-related health decline. Several lines of evidence suggest that interventions that stimulate mitochondrial autophagy (mitophagy) can slow aging and prolong healthy lifespan. Prohibitins (PHB1 and PHB2) assemble at the mitochondrial inner membrane and are critical for mitochondrial homeostasis. In addition, prohibitins (PHBs) have diverse roles in cell and organismal biology. Here, we will discuss the role of PHBs in mitophagy, oxidative phosphorylation, cellular senescence, and apoptosis. We will also discuss the role of PHBs in modulating lifespan. In addition, we will review the links between PHBs and diseases of aging. Finally, we will discuss the emerging concept that PHBs may represent an attractive therapeutic target to counteract aging and age-onset disease.

Asymmetric cell division and replicative aging: a new perspective from the spindle poles

Although cell division is usually portrayed as an equitable process by which a progenitor cell originates two identical daughter cells, there are multiple examples of asymmetric divisions that generate two cells that differ in their content, morphology and/or proliferative potential. The capacity of the cells to generate asymmetry during their division is of paramount biological relevance, playing essential roles during embryonic development, cellular regeneration and tissue morphogenesis. Problems with the proper establishment of asymmetry and polarity during cell division can give rise to cancer and neurodevelopmental disorders, as well as to also accelerate cellular aging. Interestingly, the microtubule organizing centers that orchestrate the formation of the mitotic spindle have been described among the cellular structures that can be differentially allocated during asymmetric cell divisions. This mini-review focuses on recent research from our group and others uncovering a role for the non-random distribution of the spindle-associated microtubule organizing centers in the differential distribution of aging factors during asymmetric mitoses and therefore in the maintenance of the replicative lifespan of the cells.

Mechanisms through which lithocholic acid delays yeast chronological aging under caloric restriction conditions

All presently known geroprotective chemical compounds of plant and microbial origin are caloric restriction mimetics because they can mimic the beneficial lifespan- and healthspan-extending effects of caloric restriction diets without the need to limit calorie supply. We have discovered a geroprotective chemical compound of mammalian origin, a bile acid called lithocholic acid, which can delay chronological aging of the budding yeast Saccharomyces cerevisiae under caloric restriction conditions. Here, we investigated mechanisms through which lithocholic acid can delay chronological aging of yeast limited in calorie supply. We provide evidence that lithocholic acid causes a stepwise development and maintenance of an aging-delaying cellular pattern throughout the entire chronological lifespan of yeast cultured under caloric restriction conditions. We show that lithocholic acid stimulates the aging-delaying cellular pattern and preserves such pattern because it specifically modulates the spatiotemporal dynamics of a complex cellular network. We demonstrate that this cellular network integrates certain pathways of lipid and carbohydrate metabolism, some intercompartmental communications, mitochondrial morphology and functionality, and liponecrotic and apoptotic modes of aging-associated cell death. Our findings indicate that lithocholic acid prolongs longevity of chronologically aging yeast because it decreases the risk of aging-associated cell death, thus increasing the chance of elderly cells to survive.

Saccharomyces cerevisiae displays an increased growth rate and an extended replicative lifespan when grown under respiratory conditions in the presence of bacteria

Individual cells of the budding yeast Saccharomyces cerevisiae have a limited replicative potential, referred to as the replicative lifespan. We have found that both the growth rate and average replicative lifespan of S. cerevisiae cells are greatly increased in the presence of a variety of bacteria. The growth and lifespan effects are not observable when yeast are allowed to ferment glucose but are only notable on solid media when yeast are forced to respire due to the lack of a fermentable carbon source. Growth near strains of Escherichia coli containing deletions of genes needed for the production of compounds used for quorum sensing or for the production of the siderophore enterobactin also still induced the lifespan extension in yeast. Furthermore, the bacterially induced increases in growth rate and lifespan occur even across gaps in the growth medium, indicating that the bacteria are influencing the yeast through the action of a volatile compound.