Porphyromonas gulae Has Virulence and Immunological Characteristics Similar to Those of the Human Periodontal Pathogen Porphyromonas gingivalis

Abstract

Periodontitis is a significant problem in companion animals, and yet little is known about the disease-associated microbiota. A major virulence factor for the human periodontal pathogen Porphyromonas gingivalis is the lysyl-and arginylspecific proteolytic activity of the gingipains. We screened several Porphyromonas species isolated from companion animals-P. asaccharolytica, P. circumdentaria, P. endodontalis, P. levii, P. gulae, P. macacae, P. catoniae, and P. salivosa-for Lys-and Arg-specific proteolytic activity and compared the epithelial and macrophage responses and induction of alveolar bone resorption of the protease active species to that of Porphyromonas gingivalis. Only P. gulae exhibited Lys-and Arg-specific proteolytic activity. The genes encoding the gingipains (RgpA/B and Kgp) were identified in the P. gulae strain ATCC 51700 and all publicly available 12 draft genomes of P. gulae strains. P. gulae ATCC 51700 induced levels of alveolar bone resorption in an animal model of periodontitis similar to those in P. gingivalis W50 and exhibited a higher capacity for autoaggregation and binding to oral epithelial cells with induction of apoptosis. Macrophages (RAW 264.7) were found to phagocytose P. gulae ATCC 51700 and the fimbriated P. gingivalis ATCC 33277 at similar levels. In response to P. gulae ATCC 51700, macrophages secreted higher levels of cytokines than those induced by P. gingivalis ATCC 33277 but lower than those induced by P. gingivalis W50, except for the interleukin-6 response. Our results indicate that P. gulae exhibits virulence characteristics similar to those of the human periodontal pathogen P. gingivalis and therefore may play a key role in the development of periodontitis in companion animals. P eriodontitis is well known to occur in companion animals, particularly in dogs (1). The prevalence and severity of the disease increase with age (1). Chronic periodontitis, as diagnosed by increased periodontal pocket depth and/or gingival recession (1), has been shown to be present in 82% of dogs aged 6 to 8 years and in 96% of dogs aged 12 to 14 years (2). Black-pigmented anaerobic bacteria are commonly isolated from the periodontal pockets of dogs (3-5), with many of the isolates being identified as Porphyromonas species: P. asaccharolytica, P. circumdentaria, P. endodontalis, P. levii, P. gulae, P. macacae, P. catoniae, and P. salivosa. Of these species, Porphyromonas gulae has been found to be the predominant species (6). In humans, chronic periodontitis is an inflammatory disease of the supporting tissues of the teeth, which results in the destruction of the alveolar bone and the supporting tissue (7). It has been estimated to affect up to 25% of the dentate population, with severe forms affecting 5 to 6% and prevalence increasing with age (8, 9). Although the etiology of chronic periodontitis is multifactorial, evidence suggests that the levels of specific Gram-negative, anaerobic, black-pigmented bacteria in the subgingival plaque biofilm play a major role in the pathogenesis of hum...

Treatment of Porphyromonas gulae infection and downstream pathology in the aged dog by lysine‐gingipain inhibitor COR388

“…Kgp from P. gulae and P. gingivalis have similar amino acid sequences and specific activity, suggesting similar functionality on substrates . Using in vitro substrate cleavage assays, we characterized the specific activity of Kgp from two species of P. gingivalis as well as P. gulae .…”

“…Kgp from P. gulae and P. gingivalis have similar amino acid sequences and specific activity, suggesting similar functionality on substrates. 22 Using in vitro substrate cleavage assays, we characterized the specific activity of Kgp from two species of P. gingivalis as well as P. gulae. Proteolytic activity using the Z-His-Glu-Lys-MCA peptide substrate was assayed from bacterial cultures to assess activity of bacterial surface-associated Kgp as well as bacterial lysates in a buffer which preserves protease activity.…”

“…It was originally thought that P. gulae was the animal biotype of P. gingivalis , but recent research indicates that P. gulae is also found in humans with periodontal disease, and is able to adhere to and invade human gingival epithelial cells . Importantly, P. gingivalis and P. gulae are the only bacterial species known to produce gingipains, which include the arginine‐gingipains RgpA/B in addition to Kgp . Oral biofluid sampling in dogs enabled us to analyze COR388 Kgp target engagement and pharmacologic effects on P. gulae bacterial load at multiple time points and doses.…”

“…21 Importantly, P. gingivalis and P. gulae are the only bacterial species known to produce gingipains, which include the arginine-gingipains RgpA/B in addition to Kgp. 22 Oral biofluid sampling in dogs enabled us to analyze COR388 Kgp target engagement and pharmacologic effects on P. gulae bacterial load at multiple time points and doses. These data were used to understand the pharmacology of COR388 in naturally infected tissues and biofluids of the oral cavity.…”

Periodontal disease in free‐ranging koalas (Phascolarctos cinereus) from the Mount Lofty Ranges, South Australia, and its association with koala retrovirus infection

“…One concept proposed was the keystone pathogen hypothesis, where relatively low‐abundance specific bacterial species have a disproportional effect on the whole bacterial community . Recent advances in the pathogenesis of periodontitis suggest that specific keystone periopathogens, Porphyromonas gingivalis in human periodontitis, Porphyromonas gulae in animals and possibly Porphyromonas loveana in marsupials, cause disease progression by changing a synergistic healthy microbial community to a dysbiotic, disease‐inducing community . In addition, P. gingivalis , even as a low‐abundance oral microbial pathogen, can elevate the virulence of the entire microbial community by interactive communication with accessory pathogens that are part of the mixed bacterial community.…”