Rescue from lethal Shiga toxin 2-induced renal failure with a cell-permeable peptide

Abstract

Background Intestinal infection with Shiga toxin (Stx)-producing E.coli is a leading cause of hemolytic uremic syndrome and acute renal injury in otherwise healthy children in the US. Antibiotics are contraindicated and a therapeutic priority is agents that act intracellularly against the bacterial toxins which drive kidney injury. Our aim was to evaluate whether intravenous administration of a cell-permeable peptide (TVP) that binds to Stx2 will reduce disease severity and rescue juvenile baboons from a lethal Stx2 dose (50ng/kg). Methods TVP (5mg/kg) was delivered i.v. simultaneously with toxin (prevention protocol) or at 6 or 24 hours after toxin with daily 1mg/kg supplements up to Day 4 (rescue protocols). Biomarkers were monitored in blood and urine up to 28 days. Results and Conclusions TVP therapy resulted in either absence of clinical signs of acute kidney injury and normal urine output (prevention), or delayed and reduced BUN and creatinine levels (rescue) with concomitant survival. Delayed peptide administration significantly reduced thrombocytopenia, but surprisingly did not alter anemia even when monitored for 28 days in rescued survivors. This is the first successful cell-permeable therapeutic that counteracts Stx2 lethality in an animal model which recapitulates many of the human responses to enteric infection.

Oral Intoxication of Mice with Shiga Toxin Type 2a (Stx2a) and Protection by Anti-Stx2a Monoclonal Antibody 11E10

“…However, the rescue time frame may be increased if a larger MAb dose is provided or if additional doses are delivered. In support of the latter hypothesis, another group was able to rescue baboons 24 h after intravenous intoxication with Stx2a by providing a therapeutic dose of TVP, an acetylated tetravalent peptide, daily until day 4 (45). We believe that passive Ab transfer is a viable therapeutic option for STEC infections.…”

Recent Advances in Understanding Enteric Pathogenic Escherichia coli

“…Alternatively, short peptides may block Stx2 transport through epithelial cells (385). These cell-permeative peptides were also protective in a baboon model following Stx2 injection, as renal injury was abated (386). Cytotoxicity of both Stx1 and Stx2 could be neutralized with globotriose conjugated to the polysaccharide chitosan, by binding the toxin (387).…”

Affinity-Based Screening of Tetravalent Peptides Identifies Subtype-Selective Neutralizers of Shiga Toxin 2d, a Highly Virulent Subtype, by Targeting a Unique Amino Acid Involved in Its Receptor Recognition

“…Stx2a (10,11) and Stx2d, which is activated by elastase derived from the intestinal mucosa (12)(13)(14), are highly virulent and have been linked with HUS, the most serious sequela of EHEC infection. The pathophysiologic importance of these subtypes was also confirmed by the finding that Stx2a and Stx2d are highly toxic when injected into mice (15,16) or primates (17)(18)(19). Therefore, Stx neutralizers, particularly those customized to specifically neutralize Stx2a and Stx2d, would be highly valuable therapeutic agents for treating infections caused by various EHEC strains.…”

“…By targeting Stx2a receptor-binding site 3 or Stx1a site 1, we identified various tetravalent peptides demonstrating remarkable therapeutic potency in both a mouse model of EHEC infection (34,36) and a nonhuman primate model (19). Recently, we established a novel technique to determine a wide range of binding motifs for the B subunit by directly screening hundreds of divalent peptides synthesized on a cellulose membrane.…”