Pegylated bisacycloxypropylcysteine, a diacylated lipopeptide ligand of TLR6, plays a host-protective role against experimental Leishmania major infection.

Abstract

TLRs recognize pathogen-expressed Ags and elicit host-protective immune response. Although TLR2 forms heterodimers with TLR1 or TLR6, recognizing different ligands, differences in the functions of these heterodimers remain unknown. In this study, we report that in Leishmania major-infected macrophages, the expression of TLR1 and TLR2, but not TLR6, increased; TLR2-TLR2 association increased, but TLR2-TLR6 association diminished. Lentivirus-expressed TLR1-short hairpin RNA (shRNA) or TLR2-shRNA administration reduced, but TLR6-shRNA increased L. major infection in BALB/c mice. Corroboratively, Pam3CSK4 (TLR1-TLR2 ligand) and peptidoglycan (TLR2 ligand) increased L. major infection but reduced TLR9 expression, whereas pegylated bisacycloxypropylcysteine (BPPcysMPEG; TLR2-TLR6 ligand) reduced L. major number in L. major-infected macrophages, accompanied by increased TLR9 expression, higher IL-12 production, and inducible NO synthase expression. Whereas MyD88, Toll/IL-1R adaptor protein, and TNFR-α-associated factor 6 recruitments to TLR2 were not different in Pam3CSK4-, peptidoglycan-, or BPPcysMPEG-treated macrophages, only BPPcysMPEG enhanced p38MAPK and activating transcription factor 2 activation. BPPcysMPEG conferred antileishmanial functions to L. major-infected BALB/c-derived T cells in a macrophage-T cell coculture and in BALB/c mice; the protection was TLR6 dependent and IL-12 dependent, and it was accompanied by reduced regulatory T cell number. BPPcysMPEG administration during the priming with fixed L. major protected BALB/c mice against challenge L. major infection; the protection was accompanied by low IL-4 and IL-10, but high IFN-γ productions and reduced regulatory T cells. Thus, BPPcysMPEG, a novel diacylated lipopeptide ligand for TLR2-TLR6 heterodimer, induces IL-12-dependent, inducible NO synthase-dependent, T-reg-sensitive antileishmanial protection. The data reveal a novel dimerization partner-dependent duality in TLR2 function.

• Authors: Surya Prakash Pandey, Himanshu Singh Chandel, Sunit Srivastava, Sathishkumar Selvaraj, Mukesh Kumar Jha, Divanshu Shukla, Thomas Ebensen, Carlos A Guzman, Bhaskar Saha
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 193 Issue 7 Pg. 3632-43 (Oct 01 2014) ISSN: 1550-6606 [Electronic] United States
• PMID: 25194056 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 by The American Association of Immunologists, Inc.

Chemical References

• Cytokines
• Hnf1b protein, mouse
• Ligands
• Lipopeptides
• Pam(3)CSK(4) peptide
• S-(2,3-bispalmitoyloxypropyl)-cysteinyl-amido-monomethoxyl polyethylene glycol
• Tlr2 protein, mouse
• Tlr6 protein, mouse
• Tlr9 protein, mouse
• Toll-Like Receptor 1
• Toll-Like Receptor 2
• Toll-Like Receptor 6
• Toll-Like Receptor 9
• Hepatocyte Nuclear Factor 1-beta
• Polyethylene Glycols
• Nitric Oxide Synthase Type II
• Nos2 protein, mouse
• p38 Mitogen-Activated Protein Kinases

Topics

• Animals
• Cytokines (genetics, immunology)
• Gene Expression Regulation (drug effects, genetics, immunology)
• Hepatocyte Nuclear Factor 1-beta (genetics, immunology)
• Leishmania major (immunology)
• Leishmaniasis, Cutaneous (genetics, immunology, pathology)
• Ligands
• Lipopeptides (pharmacology)
• Macrophages, Peritoneal (immunology, parasitology, pathology)
• Mice
• Mice, Inbred BALB C
• Mice, Knockout
• Nitric Oxide Synthase Type II (genetics, immunology)
• Polyethylene Glycols (pharmacology)
• T-Lymphocytes, Regulatory (immunology, pathology)
• Toll-Like Receptor 1 (genetics, immunology)
• Toll-Like Receptor 2 (immunology)
• Toll-Like Receptor 6 (agonists, genetics, immunology)
• Toll-Like Receptor 9 (genetics, immunology)
• p38 Mitogen-Activated Protein Kinases (genetics, immunology)