Lipopolysaccharide (LPS) is the principal proinflammatory component of the Gram-negative bacterial envelope and is recognized by the Toll-like receptor 4 (TLR4)–MD-2 receptor complex. Bacteria can alter the acylation state of their LPS in response to environmental changes. One opportunistic bacterium, Pseudomonas aeruginosa, synthesizes more highly acylated (hexa-acylated) LPS structures during adaptation to the cystic fibrosis airway. Here we show that human, but not murine, TLR4–MD-2 recognizes this adaptation and transmits robust proinflammatory signals in response to hexa-acylated but not penta-acylated LPS from P. aeruginosa. Whereas responses to lipidIVA and taxol are dependent on murine MD-2, discrimination of P. aeruginosa LPS structures is mediated by an 82-amino-acid region of human TLR4 that is hypervariable across species. Thus, in contrast to mice, humans use TLR4 to recognize a molecular signature of bacterial-host adaptation to modulate the innate immune response.
Subscribe to Journal
Get full journal access for 1 year
only $18.75 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Raetz, C. R. H. Bacterial lipopolysaccharides: a remarkable family of bioactive macroamphiphiles, in Escherichia coli and Salmonella (ed. Neidhardt, F. C.) 1035–1063 (ASM, Washington DC, 1996).
Beutler, B. Tlr4: central component of the sole mammalian LPS sensor. Curr. Opin. Immunol. 12, 20–26 (2000).
Poltorak, A., Ricciardi-Castagnoli, P., Citterio, S. & Beutler, B. Physical contact between lipopolysaccharide and toll-like receptor 4 revealed by genetic complementation. Proc. Natl Acad. Sci. USA 97, 2163–2167 (2000).
Lien, E. et al. Toll-like receptor 4 imparts ligand-specific recognition of bacterial lipopolysaccharide. J. Clin. Invest. 105, 497–504 (2000).
Poltorak, A. et al. Defective LPS signaling in C3H/HeJ and C57BL/10ScCr mice: mutations in Tlr4 gene. Science 282, 2085–2088 (1998).
Qureshi, S. T. et al. Endotoxin-tolerant mice have mutations in Toll-like receptor 4 (Tlr4). J. Exp. Med. 189, 615–625 (1999).
Takeuchi, O. et al. Differential roles of TLR2 and TLR4 in recognition of Gram-negative and Gram-positive bacterial cell wall components. Immunity 11, 443–451 (1999).
Hoshino, K. et al. Cutting edge: Toll-like receptor 4 (TLR4)-deficient mice are hyporesponsive to lipopolysaccharide: evidence for TLR4 as the Lps gene product. J. Immunol. 162, 3749–3752 (1999).
da Silva Correia, J., Soldau, K., Christen, U., Tobias, P. S. & Ulevitch, R. J. Lipopolysaccharide is in close proximity to each of the proteins in its membrane receptor complex: Transfer from CD14 to TLR4 and MD-2. J. Biol. Chem. 276, 21129–21135 (2001).
Shimazu, R. et al. MD-2, a molecule that confers lipopolysaccharide responsiveness on Toll- like receptor 4. J. Exp. Med. 189, 1777–1782 (1999).
Akashi, S. et al. Cutting edge: cell surface expression and lipopolysaccharide signaling via the toll-like receptor 4–MD-2 complex on mouse peritoneal macrophages. J. Immunol. 164, 3471–3475 (2000).
Visintin, A., Mazzoni, A., Spitzer, J. A. & Segal, D. M. Secreted MD-2 is a large polymeric protein that efficiently confers lipopolysaccharide sensitivity to Toll-like receptor 4. Proc. Natl Acad. Sci. USA 98, 12156–12161 (2001).
Ulevitch, R. J. & Tobias, P. S. Receptor-dependent mechanisms of cell stimulation by bacterial endotoxin. Annu. Rev. Immunol. 13, 437–457 (1995).
Guo, L. et al. Regulation of lipid A modifications by Salmonella typhimurium virulence genes phoP-phoQ. Science 276, 250–253 (1997).
Ernst, R. K. et al. Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa. Science 286, 1561–1565 (1999).
Guo, L. et al. Lipid A acylation and bacterial resistance against vertebrate antimicrobial peptides. Cell 95, 189–198 (1998).
Gunn, J. S. et al. PmrA-PmrB-regulated genes necessary for 4-aminoarabinose lipid A modification and polymyxin resistance. Mol. Microbiol. 27, 1171–1182 (1998).
Gunn, J. S., Ryan, S. S., Van Velkinburgh, J. C., Ernst, R. K. & Miller, S. I. Genetic and functional analysis of a PmrA-PmrB–regulated locus necessary for lipopolysaccharide modification, antimicrobial peptide resistance, and oral virulence of Salmonella enterica serovar typhimurium. Infect. Immun. 68, 6139–6146 (2000).
Burns, J. L. et al. Longitudinal assessment of Pseudomonas aeruginosa in young children with cystic fibrosis. J. Infect. Dis. 183, 444–452 (2001).
Davis, P. B., Drumm, M. & Konstan, M. W. Cystic fibrosis. Am. J. Respir. Crit. Care Med. 154, 1229–1256 (1996).
Pilewski, J. M. & Frizzell, R. A. Role of CFTR in airway disease. Physiol. Rev. 79, S215–S255 (1999).
Somerville, J. E. Jr, Cassiano, L., Bainbridge, B., Cunningham, M. D. & Darveau, R. P. A novel Escherichia coli lipid A mutant that produces an antiinflammatory lipopolysaccharide. J. Clin. Invest. 97, 359–365 (1996).
Walker, K. & Croteau, R. Taxol biosynthesis: molecular cloning of a benzoyl-CoA:taxane 2α-O-benzoyltransferase cDNA from taxus and functional expression in Escherichia coli. Proc. Natl Acad. Sci. USA 97, 13591–13596 (2000).
Kawasaki, K. et al. Mouse toll-like receptor 4–MD-2 complex mediates lipopolysaccharide-mimetic signal transduction by Taxol. J. Biol. Chem. 275, 2251–4. (2000).
Akashi, S. et al. Human MD-2 confers on mouse Toll-like receptor 4 species-specific lipopolysaccharide recognition. Int. Immunol. 13, 1595–1599 (2001).
Hirschfeld, M., Ma, Y., Weis, J. H., Vogel, S. N. & Weis, J. J. Cutting edge: Repurification of lipopolysaccharide eliminates signaling through both human and murine Toll-like receptor 2. J. Immunol. 165, 618–622 (2000).
Arbour, N. C. et al. TLR4 mutations are associated with endotoxin hyporesponsiveness in humans. Nat. Genet. 25, 187–191 (2000).
Bateman, A. et al. The Pfam protein families database. Nucleic Acids Res. 28, 263–266 (2000).
Bals, R., Weiner, D. J. & Wilson, J. M. The innate immune system in cystic fibrosis lung disease. J. Clin. Invest. 103, 303–307 (1999).
Guggino, W. B. Cystic fibrosis and the salt controversy. Cell 96, 607–610 (1999).
Guggino, W. B. Cystic fibrosis salt/fluid controversy: in the thick of it. Nat. Med. 7, 888–889 (2001).
Grubb, B. R. & Boucher, R. C. Pathophysiology of gene-targeted mouse models for cystic fibrosis. Physiol. Rev. 79, S193–S214 (1999).
O'Brien, A. D. et al. Genetic control of susceptibility to Salmonella typhimurium in mice: role of the LPS gene. J. Immunol. 124, 20–24 (1980).
Supajatura, V. et al. Protective roles of mast cells against enterobacterial infection are mediated by toll-like receptor 4. J. Immunol. 167, 2250–2256 (2001).
Hajjar, A. M. et al. Cutting edge: functional interactions between toll-like receptor (TLR) 2 and TLR1 or TLR6 in response to phenol-soluble modulin. J. Immunol. 166, 15–19 (2001).
Rozas, J. & Rozas, R. DnaSP version 3: an integrated program for molecular population genetics and molecular evolution analysis. BioInformatics 15, 174–175 (1999).
We thank D. T. Golenbock for lipidIVA and RS lipid A; R. Medzhitov for the hTLR4 construct; K. Miyake for the MD-2 constructs; A. Perchellet for help with preparing the hCD14 construct; and E. Sokurenko for suggestions. Supported by grants from the CF Foundation (R565-Wilson) and from the NIH (HL69503-Hajjar, HL65898-Wilson and AI47938-Miller).
The authors declare no competing financial interests.
About this article
Cite this article
Hajjar, A., Ernst, R., Tsai, J. et al. Human Toll-like receptor 4 recognizes host-specific LPS modifications. Nat Immunol 3, 354–359 (2002). https://doi.org/10.1038/ni777
Frontiers in Immunology (2020)
Journal of Cellular Physiology (2020)
Sex-Specific Regulation of Gene Expression Networks by Surfactant Protein A (SP-A) Variants in Alveolar Macrophages in Response to Klebsiella pneumoniae
Frontiers in Immunology (2020)
Isolation of Anti-Inflammatory and Epithelium Reinforcing Bacteroides and Parabacteroides Spp. from A Healthy Fecal Donor
Human microbiota-transplanted C57BL/6 mice and offspring display reduced establishment of key bacteria and reduced immune stimulation compared to mouse microbiota-transplantation
Scientific Reports (2020)