title: Leptospira surface adhesin (Lsa21) induces Toll like receptor 2 and 4 mediated inflammatory responses in macrophages.
abstract: Leptospirosis is zoonotic and emerging infectious disease of global importance. Little is understood about Leptospira pathogenesis and host immune response. In the present work we have investigated how Leptospira modulates the host innate immune response mediated by Toll-like receptors (TLRs) via surface exposed proteins. We screened Leptospira outer membrane/surface proteins for their ability to activate/inhibit TLR2/4 signaling in HEK293 cell lines. Of these the 21 kDa Leptospira surface adhesin, Lsa21 had strong TLR2 and TLR4 activity leading to production of proinflammatory cytokines and expression of costimulatory molecules in mouse macrophages. This activity of Lsa21 on innate response was dependent on activation of mitogen activated protein kinases (MAPKs) via stimulating the rapid phosphorylation of p38, JNK and activation of transcription factor NF-κB. Additionally, neutralizing antibodies against TLR2 and TLR4 significantly inhibited cytokine secretion and attenuated Lsa21 induced phosphorylation of p38 and JNK. Furthermore, Lsa21 induced cytokine levels were significantly lower in TLR2-/-and TLR4-/-than in wild type mouse macrophage cell lines. Confocal microscopy and molecular docking confirmed that Lsa21 interacted with both TLR2 and TLR4. These results indicate that Lsa21 is a potent TLR2 and TLR4 agonist that induces strong innate response and may play important role in Leptospira pathogenesis.
authors.affiliation: National Institute of Animal Biotechnology, Hyderabad, India.
authors.forename: Syed M
authors.initials: SM
authors.lastname: Faisal
authors.affiliation: National Institute of Animal Biotechnology, Hyderabad, India.
authors.forename: Vivek P
authors.initials: VP
authors.lastname: Varma
authors.affiliation: National Institute of Animal Biotechnology, Hyderabad, India.
authors.forename: M
authors.initials: M
authors.lastname: Subathra
authors.affiliation: National Institute of Animal Biotechnology, Hyderabad, India.
authors.forename: Sarwar
authors.initials: S
authors.lastname: Azam
authors.affiliation: National Institute of Animal Biotechnology, Hyderabad, India.
authors.forename: Anil K
authors.initials: AK
authors.lastname: Sunkara
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India.
authors.forename: Mohd
authors.initials: M
authors.lastname: Akif
authors.affiliation: Centre for Biosciences and Biomedical Engineering, Indian Institute of Technology, Indore, MP, India.
authors.forename: Mirza S
authors.initials: MS
authors.lastname: Baig
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Yung-Fu
authors.initials: YF
authors.lastname: Chang
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology*; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D002460:Cell Line; D016207:Cytokines / Q000276:immunology; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007113:Immunity, Innate; D007249:Inflammation; D007919:Leptospira; D007922:Leptospirosis / Q000276:immunology*; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D053594:Myeloid Differentiation Factor 88 / Q000276:immunology; D010766:Phosphorylation; D025941:Protein Interaction Mapping; D000067996:RAW 264.7 Cells; D011994:Recombinant Proteins / Q000276:immunology; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000276:immunology*; D051197:Toll-Like Receptor 4 / Q000276:immunology*
chemical_list: D018829:Adhesins, Bacterial; D057134:Antibodies, Neutralizing; D016207:Cytokines; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D011994:Recombinant Proteins; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4