Toxic stress-specific cytoprotective responses regulate learned behavioral decisions in C. elegans

Area of Science:

• Neuroscience
• Molecular Biology
• Behavioral Biology

Background:

• Survival hinges on effective stress recognition and "fight-or-flight" responses.
• Previous research indicates pathogen/toxin exposure in C. elegans triggers stress, detoxification, and avoidance behaviors.
• The coordinated regulation between cytoprotective stress responses and behavioral defenses remains poorly understood.

Purpose of the Study:

• To investigate the coordinated regulation between cytoprotective stress responses and behavioral defenses in C. elegans.
• To explore how preconditioning with specific odors affects physiological and behavioral responses to subsequent stress.
• To identify molecular mediators of inter-tissue communication between cellular and behavioral defenses.

Main Methods:

• Exposure of Caenorhabditis elegans to food-derived odors (benzaldehyde, diacetyl) to induce toxicity and avoidance.
• Analysis of systemic cytoprotective stress responses involving DAF-16/FOXO, SKN-1/Nrf2, and Hsp90.
• Investigation of behavioral cross-tolerance and memory formation using spaced training and olfactory cue retrieval.
• Identification of mediating pathways including JNK-like stress-activated protein kinases and NPR-1.

Main Results:

• Benzaldehyde preconditioning induced physiological and behavioral tolerance to benzaldehyde and cross-tolerance to methyl-salicylate, but not diacetyl.
• Diacetyl preconditioning paradoxically augmented avoidance and weakened tolerance, without inducing molecular defenses.
• Inter-tissue communication between cellular and behavioral defenses involves JNK-like kinases and NPR-1.
• Spaced training led to stable, stress-specific memories influencing future behavioral decisions.
• Memory retrieval mediated context-dependent avoidance of contaminated food and selective avoidance of benzaldehyde.

Conclusions:

• A regulatory link exists between conserved cytoprotective stress responses and behavioral avoidance, crucial for self-protection.
• These findings illuminate the biological basis of "fight-or-flight" responses.
• The efficiency of past physiological stress protection can shape current behavioral decision-making.