Involvement of Sialic Acid in Transport of Serotype C1 Botulinum Toxins through Rat Intestinal Epithelial Cells

Abstract

ABSTRACT. Clostridium botulinum produces a large toxin complex (L-TC) composed of neurotoxin (BoNT) and non-toxic proteins. In animal botulism, BoNT or L-TC is absorbed via the intestinal epithelium. To establish the cellular mechanisms of botulinum toxin absorption, we used cultured rat intestinal epithelial cells to test the binding and transport of serotype C1 BoNT and L-TC through the cell layers. BoNT and L-TC bound to and passed through the cell layers, with L-TC exhibiting larger binding and transport. Binding and transport of these toxins were inhibited by N-acetyl neuraminic acid or neuraminidase treatment of the cells. These results suggest that binding of serotype C1 BoNT and L-TC to sialic acid on the cells promoted their transport through intestinal epithelial cell layers.KEY WORDS: botulinum neurotoxin, Clostridium botulinum, IEC-6, toxin absorption, toxin complex.

Crystal Structure of Clostridium botulinum Whole Hemagglutinin Reveals a Huge Triskelion-shaped Molecular Complex

“…These data provide evidence that HA1 plays an important role in the first step of HA action and that the HA2-HA3 complex is necessary and sufficient for the second step. Our results are consistent with the observation that the carbohydrate-binding activity of HA1 in the 16 S toxin plays an important role in the binding and transport of the toxin complex across intestinal epithelial monolayers (9,10,(13)(14)(15)(16)(17)(18). In the structure of whole HA, the orientation of the BoNT-NTNH binding side was easily inferred from studies of negative-stain electron microscopy of 16 S toxins (37,38).…”

“…Using this system, we obtained the first x-ray crystallographic structure of whole HA. The results of our structure-function studies suggest that HA1 proteins, which play a critical role in cell binding (9,10,(13)(14)(15)(16)(17)(18), are located in the most distal part of the complex, whereas the E-cadherinbinding site is in the inner part of the complex, the HA2-HA3 connecting region.…”

Is downer cow syndrome related to chronic botulism?

“…The measured IgG antibodies in blood serum of animals are assumed to be antibodies resulting from the interaction with BoNTs, BoNTs complexes and progenitor toxins (PT) (Nakamura et al 2007, Fujinaga 2010 hence C. botulinum serotypes C and D possess five genes involved in the progenitor constituents and produce two types of PT, M-PT (a complex of BoNT and NTNHA) and L-PT (a complex of M-PT and HAs). The L-TP containing HA-33 component transport across the intestinal epithelial cell monolayer is more effective than pure BoNTs (Fujinaga et al 1997, Inui et al 2010, Sagane et al 2012. Antagonistic bacteria (enterococci) are very important in preventing germination and proliferation of C. botulinum in the gastrointestinal tract inhibits 5-enolpyruvyl shikimate 3-phosphate synthase (EPSPS), an enzyme of the shikimate pathway in plants, bacteria, fungi, algae and protozoa (Barry and Padgette 1992).…”

Botulinum Toxin Complex: A Delivery Vehicle of Botulinum Neurotoxin Traveling Digestive Tract

“…Of the nontoxic components of the botulinum TC, HA-33 component exposed outermost of the complex, and possesses an ability to recognize sugar chains on intestinal microvilli. Additionally a series of the investigations indicated that the L-TC containing HA-33 components transports across the intestinal epithelial cell monolayer more effectively than pure BoNT [14,37,38]. Therefore the HA-33 component appears to play a role in the transport of the TC across the intestinal epithelium.…”