SaaS sRNA promotes Salmonella intestinal invasion via modulating MAPK inflammatory pathway

Abstract

Salmonella Enteritidis is a foodborne enteric pathogen that infects humans and animals, utilizing complex survival strategies. Bacterial small RNA (sRNA) plays an important role in these strategies. However, the virulence regulatory network of S . Enteritidis remains largely incomplete and knowledge of gut virulence mechanisms of sRNAs is limited. Here, we characterized the function of a previously identified S almonella a dhesive- a ssociated s RNA (SaaS) in the intestinal pathogenesis of S . Enteritidis. We found that SaaS promoted bacterial colonization in both cecum and colon of a BALB/c mouse model; it was preferentially expressed in colon. Moreover, our results showed that SaaS enhanced damage to mucosal barrier by affecting expressions of antimicrobial products, decreasing the number of goblet cells, suppressing mucin gene expression, and eventually reducing thickness of mucus layer; it further breached below physical barrier by strengthening invasion into epithelial cells in Caco-2 cell model as well as decreasing tight junction expressions. High throughput 16S rRNA gene sequencing revealed that SaaS also altered gut homeostasis by depleting beneficial gut microbiota while increasing harmful ones. Furthermore, by employing ELISA and western blot analysis, we demonstrated that SaaS regulated intestinal inflammation through sequential activation P38-JNK-ERK MAPK signaling pathway, which enabled immune escape at primary infection stage but strengthened pathogenesis at later stage, respectively. These findings suggest that SaaS plays an essential role in the virulence of S . Enteritidis and reveals its biological role in intestinal pathogenesis.

Multi‐omics approaches reveal inflammatory response and intestinal damage mediated by sRNA SaaS during Salmonella invasion in mice

“…Previous studies demonstrated that SaaS, a newly discovered sRNA, regulated the expression of virulence genes and contribute to the invasion of Salmonella into intestine Cai, Xie, Shao, et al, 2023). However, the impact of SaaS on the development of inflammation was found to be contradictory, with suppression observed during the middle stage but promotion on the fifth day (Cai, Xie, Shao, et al, 2023). The suppressed inflammation in 72-h time point was contrary to our prediction and the normal observation in prevalent Salmonella invasion.…”

“…Total RNA was extracted from colon samples as mentioned in Section 2.5. The reverse transcription and real-time reactions were performed as previously described (Cai, Xie, Shao, et al, 2023). Simply, 800 ng of RNA was used to reverse transcript into cDNA using a HiScript III RT SuperMix for qPCR (+gDNA wiper) (Vazyme).…”

“…Previous study has evaluated the bacterial burden, inflammatory response, and barrier function in the colon of mice that infected by Salmonella (Cai, Xie, Shao, et al, 2023). To construct the relationships between critical DEGs-DEPs (peptidoglycan recognition protein short…”

“…[PGLYRP1], transferrin receptor protein 1 [TfR1], and corticosteroid 11-beta-dehydrogenase isozyme 2 [HSD11B2]) and the above known differential phenotypes, as well as the IFN-γ levels and hemogram picture in this study, Spearman's correlation coefficients were evaluated according to previously described method (Cai, Xie, Shao, et al, 2023). Only significantly different indicators between groups were selected here.…”

Battling Salmonella enteritidis infections: integrating proteomics and in vivo assessment of Galla Chinensis tannic acid

“…Disruption of the intestinal epithelial structure facilitates the spread of S. Enteritidis to the liver and spleen [ 51 ]. GCTA treatment resulted in a significant reduction in bacterial loads within the liver and spleen, which exhibited a positive correlation with the enhanced integrity of the intestinal epithelium.…”