{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T13:30:56Z","timestamp":1777901456951,"version":"3.51.4"},"reference-count":56,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,4,3]],"date-time":"2025-04-03T00:00:00Z","timestamp":1743638400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p><jats:italic>Klebsiella pneumoniae<\/jats:italic> is the causative agent of a wide range of antibiotic-resistant infections, including nosocomial pneumonia and neonatal sepsis. We investigate here the mechanisms underlying innate immune recognition of this pathogen by focusing on the role of endosomal Toll-like receptors (TLRs), which sense prokaryotic nucleic acids, in comparison with TLR4, which recognizes the cell-wall lipopolysaccharide component. Lack of functional endosomal TLRs made mice more susceptible to pulmonary infection by <jats:italic>K. pneumoniae<\/jats:italic>, in association with reduced production of proinflammatory and chemotactic cytokines and reduced neutrophil recruitment to the lung. This phenotype was as severe as that of TLR4-deficient mice and only moderately milder than that of mice lacking the TLR adaptor MyD88. Notably, macrophages lacking at the same time TLR7, 9 and 13 were more defective than those lacking only TLR9 in their ability to produce proinflammatory cytokines, suggesting a role for the RNA sensing TLR7 and 13 receptors in <jats:italic>K. pneumoniae<\/jats:italic> recognition. Collectively, our results unveil the presence of an integrated system of DNA and RNA sensing TLRs that cooperates with TLR4 in immune detection and clearance of <jats:italic>K. pneumoniae<\/jats:italic>. These data may be useful to devise alternative therapeutic approaches aimed at stimulating responses against antibiotic-resistant <jats:italic>K. pneumoniae<\/jats:italic> strains.<\/jats:p>","DOI":"10.3389\/fimmu.2025.1538425","type":"journal-article","created":{"date-parts":[[2025,4,3]],"date-time":"2025-04-03T05:53:10Z","timestamp":1743659590000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["Role of endosomal toll-like receptors in immune sensing of Klebsiella pneumoniae"],"prefix":"10.3389","volume":"16","author":[{"given":"Giuseppe Valerio","family":"De 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