Deletion of FaeG alleviated Enterotoxigenic Escherichia coli F4ac-induced apoptosis in the intestine

Abstract

Enterotoxigenic Escherichia coli (ETEC) F4ac is a major constraint to the development of the pig industry, which is causing newborn and post-weaning piglets diarrhea. Previous studies proved that FaeG is the major fimbrial subunit of F4ac E. coli and efficient for bacterial adherence and receptor recognition. Here we show that the faeG deletion attenuates both the clinical symptoms of F4ac infection and the F4ac-induced intestinal mucosal damage in piglets. Antibody microarray analysis and the detection of mRNA expression using porcine neonatal jejunal IPEC-J2 cells also determined that the absence of FaeG subunit alleviated the F4ac promoted apoptosis in the intestinal epithelial cells. Thus, targeted depletion of FaeG is still beneficial for the prevention or treatment of F4ac infection.

Keywords: Apoptosis; Enterotoxigenic Escherichia coli (ETEC) F4ac; FaeG subunit.

Fig. 1

Effect of FaeG deletion on intestinal mucosa morphology and barrier function in piglets. a Representative H&E staining image of the small intestine (duodenum, jejunum and ileum). b Methylene blue staining results. c Serum levels of d-LA (left) and DAO (right) to evalutae the intestinal permeability, *p < 0.05, **p < 0.01

Fig. 2

The change of protein expression with different treatments in IPEC-J2 cells. Data are presented as mean ± standard deviations of three independent experiments and normalized to gapdh expression. The asterisk indicates a statistically significant differences, *p < 0.05, **p < 0.01

Fig. 3

The secretion and enzymatic activities changes of different effector caspases in IPEC-J2 cells with or without bacterial infections. a Protein expression of caspase-3 in the serum of piglets. b Protein expression of caspase-3 in the bacterial infected IPEC-J2 cells. C. Enzymatic activities of active caspase-3, -8 and -9. The control group without ETEC infection was normalized to 100%. All experiments were repeated three times and data are expressed as mean ± standard deviations (*p < 0.05, **p < 0.01)