Effects of Escherichia coli subtilase cytotoxin and Shiga toxin 2 on primary cultures of human renal tubular epithelial cells.
Shiga toxin (Stx)-producing Escherichia coli (STEC) cause post-diarrhea Hemolytic Uremic Syndrome (HUS), which is the most common cause of acute renal failure in children in many parts of the world. Several non-O157 STEC strains also produce Subtilase cytotoxin (SubAB) that may contribute to HUS pathogenesis. The aim of the present work was to examine the cytotoxic effects of SubAB on primary cultures of human cortical renal tubular epithelial cells (HRTEC) and compare its effects with those produced by Shiga toxin type 2 (Stx2), in order to evaluate their contribution to renal injury in HUS. For this purpose, cell viability, proliferation rate, and apoptosis were assayed on HRTEC incubated with SubAB and/or Stx2 toxins. SubAB significantly reduced cell viability and cell proliferation rate, as well as stimulating cell apoptosis in HRTEC cultures in a time dependent manner. However, HRTEC cultures were significantly more sensitive to the cytotoxic effects of Stx2 than those produced by SubAB. No synergism was observed when HRTEC were co-incubated with both SubAB and Stx2. When HRTEC were incubated with the inactive SubAA272B toxin, results were similar to those in untreated control cells. Similar stimulation of apoptosis was observed in Vero cells incubated with SubAB or/and Stx2, compared to HRTEC. In conclusion, primary cultures of HRTEC are significantly sensitive to the cytotoxic effects of SubAB, although, in a lesser extent compared to Stx2.
Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina.
Laura B
LB
Márquez
Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina.
Natalia
N
Velázquez
Departamento de Pediatría, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Horacio A
HA
Repetto
Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, S.A., Australia.
Adrienne W
AW
Paton
Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, S.A., Australia.
James C
JC
Paton
Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
Cristina
C
Ibarra
Laboratorio de Investigaciones Biomédicas, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina.
Claudia
C
Silberstein
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects* / Q000382:microbiology*; D004926:Escherichia coli / Q000378:metabolism; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000009:adverse effects*; D006801:Humans; D007684:Kidney Tubules / Q000187:drug effects* / Q000382:microbiology*; D022641:Shiga Toxin 2 / Q000009:adverse effects*; D013381:Subtilisins / Q000009:adverse effects*; D014709:Vero Cells / Q000187:drug effects / Q000382:microbiology
D029968:Escherichia coli Proteins; D022641:Shiga Toxin 2; D013381:Subtilisins; C527234:subtilase cytotoxin, E coli