Rapid Remodeling of the Host Epithelial Cell Proteome by the Listeriolysin O (LLO) Pore-forming Toxin

Abstract

Bacterial pathogens use various strategies to interfere with host cell functions. Among these strategies, bacteria modulate host gene transcription, thereby modifying the set of proteins synthetized by the infected cell. Bacteria can also target pre-existing host proteins and modulate their post-translational modifications or trigger their degradation. Analysis of protein levels variations in host cells during infection allows to integrate both transcriptional and post-transcriptional regulations induced by pathogens. Here, we focused on host proteome alterations induced by the toxin Listeriolysin O (LLO), secreted by the bacterial pathogen Listeria monocytogenes. We showed that a short-term treatment with LLO remodels the host cell proteome by specifically decreasing the abundance of 149 proteins. The same decrease in host protein levels was observed in different epithelial cell lines but not in macrophages. We show in particular that this proteome remodeling affects several ubiquitin and ubiquitin-like ligases and that LLO leads to major changes in the host ubiquitylome. Strikingly, this toxin-induced proteome remodeling involves only post-transcriptional regulations, as no modification in the transcription levels of the corresponding genes was observed. In addition, we could show that Perfringolysin O, another bacterial pore-forming toxin similar to LLO, also induces host proteome changes. Taken together, our data reveal that different bacterial pore-forming toxins induce important host proteome remodeling, that may impair epithelial cell functions.

Three decades of listeriology through the prism of technological advances

“…MS‐based proteomics combined with Stable Isotope Labeling of Amino acids in Cell culture (SILAC) provided a comprehensive view on protein‐level alterations in HeLa cells treated with LLO. 151 proteins were consistently decreased by LLO, including various E2 ubiquitin conjugating enzymes whose decrease was associated with reduced overall levels of K48‐ and K63‐linked polyubiquitin chains (Malet et al, ). Similarly, alterations of the cell surface proteome or surfaceome of HeLa cells were mapped upon LLO treatment by capturing N‐linked glycoproteins followed by MS analysis.…”

From the beginning to the present state of molecular microbial pathogenesis—A tribute to Pascale Cossart

“…Furthermore she could show that the host proteome alterations induced by listeriolysin involved only posttranscriptional regulations but did not lead to changes in the transcription of the corresponding genes (Malet et al, 2018).…”

Coordination of transcriptional and translational regulations in human epithelial cells infected by Listeria monocytogenes

“…One level of regulation that was not addressed in our work was protein stability, which also should consistently contribute to the timing and effectiveness of the regulations we observed. Drastic alterations in the cell proteome and protein turnover in response to Lm infection or to treatment with LLO have previously 15 been described (Malet et al, 2018;Ribet et al, 2010), and it would be interesting to integrate host proteomic data over an infection time course to assess how translation and proteome degradation contribute to reshaping the cell equipment. By western blot, we have verified that the total amounts of PABPC1 and several ribosomal proteins were not affected during the course of our experiment, probably due to their long half-lives (data not shown).…”