Fate and Biological Activity of the Antimicrobial Lasso Peptide Microcin J25 Under Gastrointestinal Tract Conditions

Abstract

The bacteriocin microcin J25 (MccJ25) inhibits the growth of Gram-negative pathogens including Salmonella and Shigella species, and Escherichia coli. This 21-amino acid peptide has remarkable stability to heat and extreme pH values and resistance to many proteases, thanks to a characteristic lasso structure. In this study, we used the dynamic simulator TIM-1 as gastro-intestinal tract model to evaluate the stability and antibacterial activity of MccJ25 during passage through the proximal portion of the human gastrointestinal tract. MccJ25 concentration was measured in the different simulator sections by HPLC, and inhibition of Salmonella enterica serotype Enteritidis was evaluated using qualitative and quantitative assays. LC-MS/MS analysis and subsequent molecular networking analysis on the Global Natural Product Social Molecular Networking platform (GNPS) and analysis of the peptide degradation in the presence of proteolytic enzymes mimicking the gastro-intestinal conditions permitted to delineate the fate of MccJ25 through identification of the main degradation products. MccJ25 was relatively stable under gastric conditions, but degraded rapidly in the compartment mimicking the duodenum, notably in the presence of pancreatin. Among pancreatin components, elastase I appeared primarily responsible for MccJ25 breakdown, while α-chymotrypsin was less efficient.

Microcin J25 Exhibits Inhibitory Activity Against Salmonella Newport in Continuous Fermentation Model Mimicking Swine Colonic Conditions

“…Previously, our group described the degradome of MccJ25 in conditions mimicking the upper portion of the human gastrointestinal tract (i.e., stomach, duodenum, and ileon), which can be obtained using a dynamic simulator model (TIM-1). This study showed high stability of MccJ25 in the stomach and partial degradation by the enzymes encountered in the duodenum (Naimi et al, 2018). However, nothing is known about the stability and activity of MccJ25 in the colon and particularly in the proximal colon, a major site of salmonellosis in pigs.…”

The manifold roles of microbial ribosomal peptide–based natural products in physiology and ecology

“…In that way, the ability of microcin J25 to compete the pathogen Salmonella in the human or animal gut conditions, as well as its stability in the different GI tract compartments, were examined using gut simulators. The degradome of microcin J25 was examined in both dynamic (TIM1 dynamic simulator) and static models of digestion, using antibacterial assays, LC-MS/MS, and molecular networking analysis (116). The stability and activity are quite good in the stomach acidic conditions, but the lassoed microcin partly degrades in the compartment mimicking the duodenum conditions, in particular upon the action of elastase, one of the main enzymes in this GI compartment, showing that protection of the microcin will be required for further applications.…”

In Silico Identification of Antimicrobial Peptides in the Proteomes of Goat and Sheep Milk and Feta Cheese

“…The former was derived from the AMPA antimicrobial peptide predictor [10,11], while the latter was quantified with respect to the peptides' affinity to endogenous proteases. Yet, the amount of cleavage recognition patterns in a given peptide sequence is only one factor in a more complex scheme that determines its actual decay rate reflecting the differential stability of peptides with different amino acid composition and different biological behaviours [37][38][39]. In order to approximate a more accurate estimation, we also incorporated HLP [19] in our ranking, a peptide half-life prediction model trained on peptide decay data from crude intestine extracts.…”