Fig. 1
From: Immunomodulation by Tetracyclines in the Critically Ill: An Emerging Treatment Option?
The immunomodulatory effects of tetracyclines in ARDS. ①By sensing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), Toll-like receptors (TLRs) become activated, thereby triggering the activation of the NLRP3 inflammasome. Tetracyclines inhibit the activation of nuclear factor-kappa B (NF-κB) and the NLRP3 inflammasome and subsequent ② release of pro-inflammatory cytokines and chemokines causes impaired ③ chemotaxis of immune cells including neutrophils. Tetracyclines further block ④ neutrophil degranulation and ⑤ extracellular matrix breakdown. ⊥ inhibition, AEC I type I alveolar epithelial cell, AEC II type II alveolar epithelial cell, BEC bronchial epithelial cell