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bioRxiv · 10.1101/2023.12.12.571267

Clustered Regularly Interspaced Short Palindromic Repeats-Cas system regulates Salmonella virulence

Marathe, S. A.·Sharma, N.·Das, A.·Sethi, P.·Nair, A. V.·Chakravortty, D.·Negi, V. D.
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Abstract

ObjectivesInvestigating the type 1-E CRISPR-Cas-mediated regulation of Salmonella pathogenesis. MethodsWe assessed the pathogenicity of the wild-type and CRISPR-Cas knockout strains using infection models. The mechanisms were elucidated using antimicrobial assays and expression analysis. ResultsCRISPR-Cas knockout strains were defective in invasion and proliferation in intestinal epithelial cells and macrophages. However, proliferation defects were not observed in the Gp91phox-/- macrophages, suggesting the systems role in antioxidant defence. The knockout strains show hampered colonization in in-vivo infection models, possibly due to increased sensitivity against innate immune barriers like antimicrobial peptides, complement proteins and oxidative stress. The expression studies of various virulence regulators: pmr genes, anti-oxidant genes, SPI-1 and SPI-2 encoded master regulators, and effectors showed repressed expression in the knockout strains. Some of these genes could be directly regulated by the CRISPR-spacers owing to partial complementarity between the sequences. ConclusionOverall, our study shows that the CRISPR-Cas system positively regulates Salmonella pathogenesis by regulating the expression of different virulence factors.

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Marathe, S. A., Sharma, N., Das, A., Sethi, P., Nair, A. V., Chakravortty, D., Negi, V. D.. 2023-12-14. Clustered Regularly Interspaced Short Palindromic Repeats-Cas system regulates Salmonella virulence. https://doi.org/10.1101/2023.12.12.571267

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