title: Filifactor alocis collagenase can modulate apoptosis of normal oral keratinocytes.
abstract: To successfully colonize host cells, pathogenic bacteria must circumvent the host's structural barrier such as the collagen-rich extracellular matrix (ECM), as a preliminary step to invasion and colonization of the periodontal tissue. Filifactor alocis possesses a putative Peptidase U32 family protein (HMPREF0389_00504) with collagenase activity that may play a significant role in colonization of host tissue during periodontitis by breaking down collagen into peptides and disruption of the host cell. Domain architecture of the HMPREF0389_00504 protein predicted the presence of a characteristic PrtC-like collagenase domain, and a peptidase domain. Our study demonstrated that the recombinant F. alocis peptidase U32 protein (designated PrtFAC) can interact with, and degrade, type I collagen, heat-denatured collagen and gelatin in a calcium-dependent manner. PrtFAC decreased viability and induced apoptosis of normal oral keratinocytes (NOKs) in a time and dose-dependent manner. Transcriptome analysis of NOK cells treated with PrtFAC showed an upregulation of the genes encoding human pro-apoptotic proteins: Apoptotic peptidase activating factor 1 (Apaf1) cytochrome C, as well as caspase 3 and caspase 9, suggesting the involvement of the mitochondrial apoptotic pathway. There was a significant increase in caspase 3/7 activity in NOK cells treated with PrtFAC. Taken together, these findings suggest that F. alocis PrtFAC protein may play a role in the virulence and pathogenesis of F. alocis.
authors.affiliation: Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
authors.forename: O
authors.initials: O
authors.lastname: Chioma
authors.affiliation: Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
authors.forename: A W
authors.initials: AW
authors.lastname: Aruni
authors.affiliation: Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
authors.forename: T-A
authors.initials: TA
authors.lastname: Milford
authors.affiliation: Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.|Institute of Oral Biology, Kyung Hee University, Seoul, Korea.
authors.forename: H M
authors.initials: HM
authors.lastname: Fletcher
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001483:Base Sequence; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism*; D017364:Collagenases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects; D005780:Gelatin / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects*; D008958:Models, Molecular; D010462:Peptostreptococcus / Q000201:enzymology* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D024042:Collagen Type I; D005780:Gelatin; D017364:Collagenases
keywords: apoptosis; collagen; collagenase; normal oral keratinocytes; periodontal disease; proteases; virulence