
Evaluation of Putative Type II Toxin-Antitoxin Systems and Lon Protease Expression in Shigella flexneri Following Infection of Caco-2 Cells
Author(s) -
Erfan Kheradmand,
Shabnam Razavi,
Malihe Talebi,
M Jamshidian
Publication year - 2020
Publication title -
archives of clinical infectious diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.22
H-Index - 14
ISSN - 2345-2641
DOI - 10.5812/archcid.98625
Subject(s) - shigella flexneri , microbiology and biotechnology , biology , antitoxin , gene , protease , shigella , gene expression , antimicrobial , toxin , enzyme , escherichia coli , genetics , biochemistry
: Shigella flexneri causes bacillary dysentery in developing countries. Due to recent reports regarding antimicrobial resistance in human S. flexneri, finding alternative therapeutics is of vital importance. Toxin-antitoxin (TA) systems have recently been introduced as antimicrobial targets owing to their involvement in bacterial survival in stress conditions and “persister” cell formation. In this study, the presence of four TA loci were studied in S. flexneri ATCC 12022. The presence of genes coding for the identified TA loci and Lon protease were confirmed by the PCR method using specific primers. Caco-2 cell lines were then infected with this standard strain, and 8 and 24 h post-infection, expression levels of genes coding for the studied TA loci, and Lon protease were evaluated using a real-time PCR method. Expression of mazF, GNAT (Gcn5-related N-acetyltransferase), yeeU, pfam13975, and Lon genes showed 5.4, 9.8, 2.3, 2.7, and 13.8-fold increase, respectively, 8 h after bacterial invasion of the Caco-2 cell line. In addition, the expression of the aforementioned genes showed 4.8, 10.8, 2.3, 3.7, and 16.8-fold increase after 24 h. The GNAT and lon genes showed significantly higher expression levels compared to the control (P value < 0.05). However, the increase in the expression level of yeeU was the same at 8 h and 24 h post-infection. In addition, mazF expression level showed a slight decrease at 24 h compared to 8h post-infection. Genes coding for GNAT and Lon protease showed a significantly higher expression after invading the Caco-2 cell line. Therefore, targeting GNAT or Lon protease can be taken into consideration for finding novel antimicrobial drug strategies. The exact functions and mechanisms of TA systems in S. flexneri isolates are suggested to be experimentally determined.