Polyamines Control eIF5A Hypusination, TFEB Translation, and Autophagy to Reverse B Cell Senescence

Area of Science:

• Immunology
• Cellular Biology
• Aging Research

Background:

• Adaptive immune responses decline with age, leading to reduced vaccination efficacy and increased infection risk in the elderly.
• Impaired B cell function is a key characteristic of immune senescence, affecting antibody production and memory cell responses.

Purpose of the Study:

• To investigate the role of autophagy in immune senescence and its impact on B cell function.
• To explore spermidine as a potential therapeutic agent to reverse age-related immune decline.

Main Methods:

• Assessed autophagy levels in lymphocytes from young and old individuals.
• Investigated the effect of spermidine supplementation on autophagy and B cell function in vitro and in vivo.
• Examined the molecular mechanism involving spermidine, eIF5A, and TFEB in regulating autophagy.

Main Results:

• Autophagy is significantly reduced in mature lymphocytes of aged individuals, correlating with compromised memory B cell responses.
• Spermidine administration in vivo restored autophagy levels and rejuvenated memory B cell function in old individuals.
• Spermidine enhances TFEB (transcription factor EB) synthesis by post-translationally modifying eIF5A (eukaryotic translation initiation factor 5A), a key step in autophagy regulation.

Conclusions:

• Reduced autophagy, mediated by spermidine depletion and impaired eIF5A-TFEB pathway, is a central mechanism of immune senescence.
• Spermidine supplementation represents a promising strategy to reverse immune senescence and improve adaptive immunity in the elderly.
• The findings reveal a novel translational control mechanism of autophagy that can be therapeutically targeted to combat age-related immune dysfunction.