PAR2, Keratinocytes, and Cathepsin S Mediate the Sensory Effects of Ciguatoxins Responsible for Ciguatera Poisoning.

Abstract

Ciguatera fish poisoning is caused by the consumption of fish contaminated with ciguatoxins (CTXs). The most distressing symptoms are cutaneous sensory disturbances, including cold dysesthesia and itch. CTXs are neurotoxins known to activate voltage-gated sodium channels, but no specific treatment exists. Peptidergic neurons have been critically involved in ciguatera fish poisoning sensory disturbances. Protease-activated receptor-2 (PAR2) is an itch- and pain-related G protein‒coupled receptor whose activation leads to a calcium-dependent neuropeptide release. In this study, we studied the role of voltage-gated sodium channels, PAR2, and the PAR2 agonist cathepsin S in the cytosolic calcium increase and subsequent release of the neuropeptide substance P elicited by Pacific CTX-2 (P-CTX-2) in rat sensory neurons and human epidermal keratinocytes. In sensory neurons, the P-CTX-2‒evoked calcium response was driven by voltage-gated sodium channels and PAR2-dependent mechanisms. In keratinocytes, P-CTX-2 also induced voltage-gated sodium channels and PAR2-dependent marked calcium response. In the cocultured cells, P-CTX-2 significantly increased cathepsin S activity, and cathepsin S and PAR2 antagonists almost abolished P-CTX-2‒elicited substance P release. Keratinocytes synergistically favored the induced substance P release. Our results demonstrate that the sensory effects of CTXs involve the cathepsin S-PAR2 pathway and are potentiated by their direct action on nonexcitable keratinocytes through the same pathway.

• Authors: Killian L'Herondelle, Ophelie Pierre, Sophie Fouyet, Raphael Leschiera, Christelle Le Gall-Ianotto, Reginald Philippe, Paul Buscaglia, Olivier Mignen, Matthieu Talagas, Richard J Lewis, Laurence Michel, Laurent Misery, Raphaele Le Garrec
• Journal: The Journal of investigative dermatology (J Invest Dermatol) Vol. 141 Issue 3 Pg. 648-658.e3 (03 2021) ISSN: 1523-1747 [Electronic] United States
• PMID: 32800876 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.

Chemical References

• Receptor, PAR-2
• Ciguatoxins
• Substance P
• Cathepsins
• cathepsin S
• Calcium

Topics

• Animals
• Calcium (metabolism)
• Cathepsins (metabolism)
• Ciguatera Poisoning (complications, pathology)
• Ciguatoxins (toxicity)
• Coculture Techniques
• Cytosol (metabolism)
• Disease Models, Animal
• Epidermis (innervation, pathology)
• Humans
• Intravital Microscopy
• Keratinocytes (drug effects, metabolism, pathology)
• Paresthesia (etiology, pathology)
• Primary Cell Culture
• Pruritus (etiology, pathology)
• Rats
• Receptor, PAR-2 (agonists, metabolism)
• Sensory Receptor Cells (drug effects, metabolism)
• Single-Cell Analysis
• Substance P (metabolism)