Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli (EHEC) cause gastrointestinal
infection and, in severe cases,
hemolytic uremic syndrome which may lead to death. There is, to-date, no
therapy for this
infection. Stx induces
ATP release from host cells and
ATP signaling mediates its cytotoxic effects.
Apyrase cleaves and neutralizes
ATP and its effect on Stx and EHEC
infection was therefore investigated.
Apyrase decreased bacterial RecA and dose-dependently decreased toxin release from E. coli O157:H7 in vitro, demonstrated by reduced phage
DNA and
protein levels. The effect was investigated in a mouse model of E. coli O157:H7
infection. BALB/c mice infected with Stx2-producing E. coli O157:H7 were treated with
apyrase intraperitoneally, on days 0 and 2 post-
infection, and monitored for 11 days.
Apyrase-treated mice developed disease two days later than untreated mice. Untreated infected mice lost significantly more weight than those treated with
apyrase.
Apyrase-treated mice exhibited less colonic goblet cell depletion and apoptotic cells, as well as lower fecal
ATP and Stx2, compared to untreated mice.
Apyrase also decreased platelet aggregation induced by co-incubation of human platelet-rich-plasma with Stx2 and E. coli O157
lipopolysaccharide in the presence of
collagen. Thus,
apyrase had multiple protective effects, reducing RecA levels, stx2 and toxin release from EHEC, reducing fecal Stx2 and protecting mouse intestinal cells, as well as decreasing platelet activation, and could thereby delay the development of disease.