Proteomic identification of secreted proteins of Propionibacterium acnes

Abstract

BackgroundThe anaerobic Gram-positive bacterium Propionibacterium acnes is a human skin commensal that resides preferentially within sebaceous follicles; however, it also exhibits many traits of an opportunistic pathogen, playing roles in a variety of inflammatory diseases such as acne vulgaris. To date, the underlying disease-causing mechanisms remain ill-defined and knowledge of P. acnes virulence factors remains scarce. Here, we identified proteins secreted during anaerobic cultivation of a range of skin and clinical P. acnes isolates, spanning the four known phylogenetic groups.ResultsCulture supernatant proteins of P. acnes were separated by two-dimensional electrophoresis (2-DE) and all Coomassie-stained spots were subsequently identified by MALDI mass spectrometry (MALDI-MS). A set of 20 proteins was secreted in the mid-exponential growth phase by the majority of strains tested. Functional annotation revealed that many of these common proteins possess degrading activities, including glycoside hydrolases with similarities to endoglycoceramidase, β-N-acetylglucosaminidase and muramidase; esterases such as lysophospholipase and triacylglycerol lipase; and several proteases. Other secreted factors included Christie-Atkins-Munch-Petersen (CAMP) factors, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and several hypothetical proteins, a few of which are unique to P. acnes. Strain-specific differences were apparent, mostly in the secretion of putative adhesins, whose genes exhibit variable phase variation-like sequence signatures.ConclusionsOur proteomic investigations have revealed that the P. acnes secretome harbors several proteins likely to play a role in host-tissue degradation and inflammation. Despite a large overlap between the secretomes of all four P. acnes phylotypes, distinct differences between predicted host-tissue interacting proteins were identified, providing potential insight into the differential virulence properties of P. acnes isolates. Thus, our data presents a rich resource for guiding much-needed investigations on P. acnes virulence factors and host interacting properties.

A novel multilocus sequence typing scheme for the opportunistic pathogen Propionibacterium acnes and characterization of type I cell surface-associated antigens

“…Furthermore, free glycerol released from sebum by lipase may act as an important carbon source and, along with the potential nutritional role also played by neuraminidase, promote growth (McGinley et al, 1980;Corfield, 1992). The demonstration of differences in the expression of dermatan-sulphate-binding proteins in this study and others (Lodes et al, 2006;Holland et al, 2010), and the observation of probable phase variation within type IA strains are likely to prove to be important observations in the context of acne pathogenesis, particularly as dermatan sulphate is the predominant glycosaminoglycan in skin and a biological response modifier involved in processes such as cytokine activity and wound repair.…”

“…Expression of neuraminidase and lipase (GehA) appears to be especially associated with type IA isolates, and the production of lipase in particular is believed to play an important role in the pathophysiology of acne (Lomholt & Kilian, 2010;Holland et al, 2010). This is due to the release of glycerol and free fatty acids from sebum triglycerides which may be inflammatory and chemotactic, and promote ductal hypercornification and adhesion between P. acnes and the hair follicle (Gribbon et al, 1993).…”

Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children

“…or proteases that may inactivate or inhibit complement (54)(55)(56)(57). It is also possible that sMAC levels in this cohort are depressed, in part, due to complement depletion, as reported in S. epidermidis infections in ventriculoatrial shunt patients (23); however, this seems less likely, as sMAC is stable relative to other complement activation products (58).…”

Multiplex Touchdown PCR for Rapid Typing of the Opportunistic Pathogen Propionibacterium acnes

“…The bacterium has an overall clonal structure, and its isolates can be classified into a number of statistically significant clades or phylogroups designated types IA 1 , IA 2 , IB, IC, II, and III; these types appear to display differences in their associations with specific types of infections (20,21) and vary in their production of putative virulence determinants (19,20,(29)(30)(31)(32), inflammatory potential (33)(34)(35)(36), antibiotic resistances (21,37), aggregative properties (16), and morphological characteristics (19). In particular, a number of independent epidemiological studies have shown a strong association between clonal complexes from the type IA 1 phylogroup and moderate-to-severe acne, while the lineages from all other phylogroups appear more frequently to be isolated from medical device and soft tissue infections or be associated with health as true commensals (20,21,31,38).…”