eIF4E phosphorylation modulates pain and neuroinflammation in the aged

Area of Science:

• Neuroscience
• Immunology
• Gerontology

Background:

• Aging increases susceptibility to chronic pain due to low-grade inflammation.
• Cap-dependent translation is implicated in pain in young adults but unstudied in aged populations.
• Altered inflammatory responses with age necessitate understanding new therapeutic pathways.

Purpose of the Study:

• To investigate the role of cap-dependent translation, specifically eukaryotic translation initiation factor 4E (eIF4E), in age-associated inflammatory pain.
• To compare the effects of an inflammatory stimulus (CFA) on pain and inflammation in young versus aged mice with and without functional eIF4E.

Main Methods:

• Utilized young and aged wild-type (WT) mice alongside age-matched transgenic mice lacking functional eIF4E.
• Administered Complete Freund's Adjuvant (CFA) to induce acute inflammation and pain.
• Assessed spontaneous and evoked pain, paw temperature, inflammation, and cytokine levels (IL-1β, TNF-α) in dorsal root ganglia.

Main Results:

• eIF4E phosphorylation modulated CFA-induced pain and inflammation in aged, but not young, mice.
• Aged transgenic mice exhibited reduced paw temperature, inflammation, and hypersensitivity onset/resolution.
• Elevated IL-1β and TNF-α were observed in aged WT and eIF4E transgenic groups, despite faster resolution in the latter.

Conclusions:

• eIF4E phosphorylation is a key factor in age-dependent inflammatory pain modulation.
• Targeting eIF4E phosphorylation offers a potential therapeutic strategy for inflammatory pain in the elderly.
• Cytokines like IL-1β and TNF-α play roles in both young and aged inflammatory pain responses.