title: FAD-I, a Fusobacterium nucleatum Cell Wall-Associated Diacylated Lipoprotein That Mediates Human Beta Defensin 2 Induction through Toll-Like Receptor-1/2 (TLR-1/2) and TLR-2/6.
abstract: We previously identified a cell wall-associated protein from Fusobacterium nucleatum, a Gram-negative bacterium of the oral cavity, that induces human beta defensin 2 (hBD-2) in primary human oral epithelial cells (HOECs) and designated it FAD-I (Fusobacterium-associated defensin inducer). Here, we report differential induction of hBD-2 by different strains of F. nucleatum; ATCC 25586 and ATCC 23726 induce significantly more hBD-2 mRNA than ATCC 10953. Heterologous expression of plasmid-borne fadI from the highly hBD-2-inducing strains in a ΔfadI mutant of ATCC 10953 resulted in hBD-2 induction to levels comparable to those of the highly inducing strains, indicating that FAD-I is the principal F. nucleatum agent for hBD-2 induction in HOECs. Moreover, anti-FAD-I antibodies blocked F. nucleatum induction of hBD-2 by more than 80%. Recombinant FAD-I (rFAD-I) expressed in Escherichia coli triggered levels of hBD-2 transcription and peptide release in HOECs similar to those of native FAD-I (nFAD-I) isolated from F. nucleatum ATCC 25586. Tandem mass spectrometry revealed a diacylglycerol modification at the cysteine residue in position 16 for both nFAD-I and rFAD-I. Cysteine-to-alanine substitution abrogated FAD-I's ability to induce hBD-2. Finally, FAD-I activation of hBD-2 expression was mediated via both Toll-like receptor-1/2 (TLR-1/2) and TLR-2/6 heterodimerization. Microbial molecules like FAD-I may be utilized in novel therapeutic ways to bolster the host innate immune response at mucosal surfaces.
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA.
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Bhattacharyya
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA.
authors.forename: Santosh K
authors.identifier: http://orcid.org/0000-0001-5669-7853
authors.initials: SK
authors.lastname: Ghosh
authors.affiliation: School of Dentistry, University of California-Los Angeles, Los Angeles, California, USA.
authors.forename: Bhumika
authors.initials: B
authors.lastname: Shokeen
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA.
authors.forename: Betty
authors.initials: B
authors.lastname: Eapan
authors.affiliation: School of Dentistry, University of California-Los Angeles, Los Angeles, California, USA.
authors.forename: Renate
authors.initials: R
authors.lastname: Lux
authors.affiliation: Center for Proteomics, Case School of Medicine, Cleveland, Ohio, USA.
authors.forename: Janna
authors.initials: J
authors.lastname: Kiselar
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Nithianantham
authors.affiliation: Department of Dermatology, Case School of Medicine, Cleveland, Ohio, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Young
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA.
authors.forename: Pushpa
authors.initials: P
authors.lastname: Pandiyan
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA.|Department of Dermatology, Case School of Medicine, Cleveland, Ohio, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: McCormick
authors.affiliation: Department of Biological Science, Case School of Dental Medicine, Cleveland, Ohio, USA aaron.weinberg@case.edu.
authors.forename: Aaron
authors.initials: A
authors.lastname: Weinberg
mesh_terms: D019943:Amino Acid Substitution; D000890:Anti-Infective Agents / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D004847:Epithelial Cells / Q000276:immunology / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D016967:Fusobacterium nucleatum / Q000276:immunology*; D006801:Humans; D014176:Protein Biosynthesis; D055503:Protein Multimerization; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D051194:Toll-Like Receptor 1 / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051216:Toll-Like Receptor 6 / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D023083:beta-Defensins / Q000096:biosynthesis*
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; C106641:DEFB4A protein, human; D004075:Diglycerides; C556141:FAD-I protein, Fusobacterium nucleatum; D012333:RNA, Messenger; D011994:Recombinant Proteins; C495342:TLR2 protein, human; C495368:TLR6 protein, human; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051216:Toll-Like Receptor 6; D023083:beta-Defensins; D003545:Cysteine