A distinct mechanism of senescence activation in amnion epithelial cells by infection, inflammation, and oxidative stress

Problem: We investigated p38MAPK activation-induced fetal membrane cell senescence in response to inflammation (tumour necrosis factor-alpha [TNF-alpha]) and infection (lipopolysaccharide [LPS1), factors associated with spontaneous preterm birth. Method of study: Primary amnion epithelial cells (AECs) were exposed to TNF-alpha, 50 ng/mL and LPS, 100 ng/mL. Cigarette smoke extract (CSE), a known OS inducer, was used as positive control. AECs were cotreated with the antioxidant N-acetyl cysteine (NAC) and p38MAPK inhibitor SB203580 to determine the effect of OS and p38MAPK. Western blot analysis was performed for active (Phospho-p38MAPK) and total p38MAPK. Senescence was determined by flow cytometry, and culture supernatants were tested for IL-6 using ELISA. Results: TNF-alpha, but not LPS, increased p38MAPK activation compared to untreated cells (P = .01). The number of senescent cells and senescence-associated IL-6 was higher in both TNF-alpha and LPS-treated cells compared to control (P = .001, P = .01, respectively). Antioxidant NA[ inhibited p38MAPK activation by TNF-alpha. p38MAPK inhibitor SB203580 reduced the development of senescence and IL-6 by INF-alpha and LPS. CSE treatment validated our current data. Conclusion: TNF-alpha caused OS-mediated p38MAPK induction, senescence, and IL-6 increase from AECs. LPS also induced senescence and IL-6 increase. Inflammatory and infectious factors may cause premature fetal cell senescence contributing to preterm birth pathophysiology.