Role of pannexin 1 in Clostridium perfringens beta-toxin-caused cell death.

Abstract

BACKGROUND:

Beta-toxin produced by Clostridium perfringens is a key virulence factor of fatal hemorrhagic enterocolitis and enterotoxemia. This toxin belongs to a family of β-pore-forming toxins (PFTs). We reported recently that the ATP-gated P2X7 receptor interacts with beta-toxin. The ATP-release channel pannexin 1 (Panx1) is an important contributor to P2X7 receptor signaling. Hence, we investigated the involvement of Panx1 in beta-toxin-caused cell death.

METHODS:

We examined the effect of Panx1 in beta-toxin-induced cell death utilizing selective antagonists, knockdown of Panx1, and binding using dot-blot analysis. Localization of Panx1 and the P2X7 receptor after toxin treatment was determined by immunofluorescence staining.

RESULTS:

Selective Panx1 antagonists (carbenoxolone [CBX], probenecid, and Panx1 inhibitory peptide) prevented beta-toxin-caused cell death in THP-1 cells. CBX did not block the binding of the toxin to cells. Small interfering knockdown of Panx1 blocked beta-toxin-mediated cell death through inhibiting the oligomer formation of the toxin. Beta-toxin triggered a transient ATP release from THP-1 cells, but this early ATP release was blocked by CBX. ATP scavengers (apyrase and hexokinase) inhibited beta-toxin-induced cytotoxicity. Furthermore, co-administration of ATP with beta-toxin enhanced the binding and cytotoxicity of the toxin.

CONCLUSIONS:

Based on our results, Panx1 activation is achieved through the interaction of beta-toxin with the P2X7 receptor. Then, ATP released by the Panx1 channel opening promotes oligomer formation of the toxin, leading to cell death.

GENERAL SIGNIFICANCE:

Pannexin 1 is a novel candidate therapeutic target for beta-toxin-mediated disease.

• Authors: Soshi Seike, Masaya Takehara, Keiko Kobayashi, Masahiro Nagahama
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1858 Issue 12 Pg. 3150-3156 (12 2016) ISSN: 0006-3002 [Print] Netherlands
• PMID: 27720686 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical References

• Bacterial Toxins
• CPB protein, Clostridium perfringens
• Connexins
• Nerve Tissue Proteins
• P2RX7 protein, human
• PANX1 protein, human
• Receptors, Purinergic P2X7
• Adenosine Triphosphate
• Hexokinase
• Apyrase
• Carbenoxolone

Topics

• Adenosine Triphosphate (metabolism)
• Apyrase (pharmacology)
• Bacterial Toxins (toxicity)
• Carbenoxolone (pharmacology)
• Cell Death (drug effects)
• Cells, Cultured
• Connexins (physiology)
• Hexokinase (pharmacology)
• Humans
• Nerve Tissue Proteins (physiology)
• Receptors, Purinergic P2X7 (physiology)