Plasma Membrane Damage Limits Replicative Lifespan in Yeast and Induces Premature Senescence in Human Fibroblasts

Geriatrics Life Sciences Immunology Medicine Cell Biology Biochemistry
plasma membrane damage replicative lifespan premature senescence yeast fibroblasts

Scientific Research Report: Plasma Membrane Damage Limits Yeast Replicative Lifespan and Induces Premature Senescence in Human Fibroblasts

Background and Research Motivation

Plasma Membrane Damage (PMD) is a phenomenon experienced by all cell types in response to environmental disturbances and spontaneous cellular activities. Previous studies have shown that PMD can lead to two outcomes: membrane repair or cell death. However, the long-term consequences of these damages, especially their impact on replicative lifespan and cellular aging, remain poorly understood. Therefore, this study aims to explore the specific effects of PMD in yeast and normal human fibroblasts, further revealing its role in the cellular aging process.

Sources and Authors

This study was collaboratively conducted by researchers from various Japanese scientific research institutions, including Kojiro Suda, Yohsuke Moriyama, Nurhanani Razali, and others, who are affiliated with the Okinawa Institute of Science and Technology Graduate University, Nagoya City University, Nagoya University, and the University of Tokyo, among others. The research findings were published in the March 2024 edition of Nature Aging, article number “https://doi.org/10.1038/s43587-024-00575-6”.

Research Methods and Procedures

Overview of Research Procedures

The study is divided into two main parts: research on yeast cells and research on human fibroblasts.

Yeast Cell Part

Procedures and Methods

  1. Development of Plasma Membrane Damage Induction Method:

    • Utilizing 0.02% sodium dodecyl sulfate (SDS) as the plasma membrane damage inducer.
    • Inducing membrane rupture and subsequent repair through calcium-dependent mechanisms.

  2. Gene Screening and Identification:

    • Conducting genome-wide screening to identify key genes associated with PMD response.
    • Using a mutant yeast gene library to screen for mutants that cannot survive in SDS-containing media.

  3. Replicative Lifespan Analysis:

    • Testing the replicative lifespan of various yeast cells, including wild-type and some mutants, under SDS-present and SDS-absent conditions.
    • Finding that overexpression of the ESCRT (Endosomal Sorting Complex Required for Transport) III activator AAA-ATPase (Vps4) and ESCRT-III (Snf7) significantly extends yeast replicative lifespan.

Human Fibroblast Part

Procedures and Methods

  1. Induction and Confirmation of Plasma Membrane Damage:

    • Using SDS, silicon, and laser damage methods to induce plasma membrane damage.
    • Confirming membrane rupture through experiments involving non-membrane penetrating fluorescent dyes.

  2. Cellular Senescence Analysis:

    • Assessing the impact of long-term culture and PMD on the proliferation and aging of human fibroblasts.
    • Utilizing SAS-β-galactosidase staining and Edu incorporation experiments to determine if cells have entered a senescent state.

  3. Gene Expression Analysis:

    • Analyzing the gene expression profile of PMD-induced senescent cells through mRNA sequencing and qPCR.
    • Noting increases in the expression of p53 and its downstream target gene p21 while observing that PMD-induced senescence does not involve the typical DNA damage response pathway.

Main Research Results

Yeast Cell Research

  1. Gene Screening:

    • Identified several genes related to PMD response in large-scale gene screenings.
    • Core discoveries include eight ESCRT-related genes essential for membrane repair.

  2. Replicative Lifespan Extension:

    • Experimental verification showed that overexpression of ESCRT activator Vps4 and ESCRT-III Snf7 significantly extends yeast replicative lifespan, while PMD reduces it.

Human Fibroblast Research

  1. Senescence Induction:

    • SDS and other PMD inducers (such as silicon, SLO (Streptolysin O)) effectively induce premature senescence in normal human fibroblasts.

  2. Gene Expression Changes:

    • PMD-induced cellular senescence is mediated through Ca2+ and the p53 pathway rather than the typical DNA damage response pathway. This is distinct from senescence caused by DNA damage or telomere shortening.

  3. Inhibition of Senescence by CHMP4B:

    • Found that overexpression of the ESCRT-III component CHMP4B can partially inhibit PMD-induced cellular senescence, suggesting that membrane repair plays a significant role in inhibiting senescence.

Conclusion and Significance

This study reveals the long-term consequences of PMD, particularly its critical role in the aging process. It enhances our understanding of PMD response mechanisms and their impacts, and offers new insights for addressing diseases associated with membrane damage, such as muscular dystrophy and Scott syndrome. Additionally, the findings suggest that accelerating membrane repair could be an effective anti-aging strategy.

Research Highlights

  1. Novel PMD Induction and Detection Methods:

    • Developed a simple and general method for PMD induction, suitable for yeast and human cell studies.

  2. Identification of Functional Genes:

    • Identified several key genes related to PMD response through genome-wide screening, providing important information for further research on membrane repair in yeast and human cells.

  3. Link Between Membrane Repair and Aging:

    • Discovered the critical role of membrane repair in regulating yeast replicative lifespan and preventing premature aging in human fibroblasts, particularly highlighting the role of the ESCRT system.

Supplementary Information

The research team also found through gene expression analysis that PMD-dependent senescent cells (PMD-Sen cells) exhibit gene expression characteristics associated with wound healing. This suggests that PMD-dependent senescent cells may accumulate at wound sites and accelerate wound healing through the secretion of the senescence-associated secretory phenotype (SASP).

Research Value

This study provides new insights into the role of PMD in cellular lifespan and aging, uncovering potential mechanisms through which PMD induces cellular senescence. These findings are significant for basic biological research and offer new theoretical foundations and directions for clinical applications.