Filifactor alocis collagenase can modulate apoptosis of normal oral keratinocytes

• Published in: Molecular oral microbiology 2017-04, Vol.32 (2), p.166-177
• Main Authors: Chioma, O., Aruni, A.W., Milford, T.‐A., Fletcher, H.M.
• Format: Article
• Language: English
• Subjects: apoptosis; Apoptosis - drug effects; Base Sequence; Cells, Cultured; collagen; Collagen Type I - metabolism; collagenase; Collagenases - chemistry; Collagenases - isolation & purification; Collagenases - metabolism; Collagenases - pharmacology; Dentistry; Epithelial Cells - drug effects; Gelatin - metabolism; Gene Expression Profiling; Humans; Keratinocytes - cytology; Keratinocytes - drug effects; Models, Molecular; normal oral keratinocytes; Peptostreptococcus - enzymology; Peptostreptococcus - metabolism; periodontal disease; proteases; Up-Regulation; virulence
• ISSN: 2041-1006; 2041-1014
• DOI: 10.1111/omi.12163

Summary 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.