The serine protease Pic as a virulence factor of atypical enteropathogenicEscherichia coli

Abstract

Autotransporter proteins (AT) are associated with bacterial virulence attributes. Originally identified in enteroaggregative Escherichia coli (EAEC), Shigella flexneri 2a and uropathogenic E. coli, the serine protease Pic is one of these AT. We have previously detected one atypical enteropathogenic E. coli strain (BA589) carrying the pic gene. In the present study, we characterized the biological activities of Pic produced by BA589 both in vitro and in vivo. Contrarily to other Pic-producers bacteria, pic in BA589 is located on a high molecular weight plasmid. PicBA589 was able to agglutinate rabbit erythrocytes, cleave mucin and degrade complement system molecules. BA589 was able to colonize mice intestines, and an intense mucus production was observed. The BA589Δpic mutant lost the capacity to colonize as well as the above-mentioned in vitro activities. Thus, Pic represents an additional virulence factor in aEPEC strain BA589, associated with adherence, colonization and evasion from the innate immune system.

Indoleacrylic Acid Produced by Commensal Peptostreptococcus Species Suppresses Inflammation

“…Furthermore, we found increased abundance of transporters for N -acetylgalactosamine, N -acetylglucosamine, and galactose as well as increased abundance of peptidase E, a serine peptidase (Figures S5C and S5D). Together these observations suggest an increased availability of smaller mucin oligosaccharides (Larsson et al, 2011) and increased depolymerization of MUC2 through the action of serine peptidases in this cohort of IBD patients (Abreu et al, 2016; McGuckin et al, 2011). …”

Diarrheagenic Escherichia coli

“…Abreu and collegues 109 have shown that the AT protein encoded by the ehaC gene, which is involved in biofilm formation in EHEC strains, was the most frequent, with a significantly higher prevalence than in tEPEC. Although the prevalence of the AT protein Pic (protein involved in intestinal colonization), formerly identified in EAEC, is not a common finding in aEPEC strains, it also appears to mediate colonization of mouse intestines, hemagglutination, mucin cleavage, and complement components degradation 110 . More recently, some aEPEC strains were shown to cause cell damage by secreting the AT protein Pet (plasmid encoded toxin) to the extracellular environment 111 …”

Serine Protease Autotransporters of the Enterobacteriaceae (SPATEs): Out and About and Chopping It Up

“…Protein involved in colonization (Pic) is a 109.8 kDa extracellular protein secreted by both EAEC (GenBank Accession No. ALT57188, AF097644.1), and Shigella flexneri 2a [39] and also atypical EPEC [96]. Pic catalyzed mucin degradation and has also been shown to confer serum resistance and hemagglutination [39].…”