Can low-grade inflammatory signaling induce cellular senescence and amplify inflammation through SASP?

Chronic, low-grade systemic inflammation—a hallmark of biological aging—actively initiates and propagates a pathological feedback loop with cellular senescence.

Mechanisms of inflammatory-induced senescence

• Signaling activation: Low-grade inflammatory stimuli engage surface receptors, activating stress-responsive kinases such as p38 MAPK via the ASK1 signalosome.
• Genotoxic stress: This signaling cascade elevates intracellular reactive oxygen species (ROS), causing persistent telomeric and genomic DNA damage.
• Cell-cycle arrest: Cytosolic DNA fragments activate the cyclic GMP-AMP synthase (cGAS)-STING pathway. Together with the DNA damage response, this upregulates the p53/p21 and p16 pathways to lock cells into permanent senescence.

SASP and inflammatory amplification

• Secretory phenotype: Once senescent, cells employ the transcription factors NF-κB and C/EBPβ to synthesize and release the senescence-associated secretory phenotype (SASP), a potent cocktail of pro-inflammatory cytokines, chemokines, and matrix metalloproteinases.
• Paracrine propagation: SASP factors act on adjacent healthy tissue, triggering secondary "bystander" senescence in neighboring cells.
• Feedback loop: The resulting localized and systemic inflammation elevates ROS and genotoxic stress, feeding back to drive further cellular senescence.

Bottom line

• Chronic low-grade inflammation and cellular senescence form a self-amplifying, bidirectional feedback loop driven by p38 MAPK, cGAS-STING, and NF-κB-mediated SASP secretion. For an aging individual, disrupting this loop using senotherapeutic or anti-inflammatory strategies represents a critical avenue for preserving tissue function and reducing systemic inflammatory burden.