Eszter Gecse, Beatrix Gilányi, Márton Csaba, Csaba Sőti
Semmelweis University, Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Budapest, Hungary
Introduction: Early life memories are particularly stable and form enduring behavioral patterns. Imprinting is characterized by a sensory cue at the critical perinatal period that evokes a life-long response critical for survival. Adult preference for odors associated perinatally with food have widely been documented both in vertebrates and nematodes, but little is known about responses to cues representing danger.
Aims: We study early and persistent molecular and behavioral responses of C. elegans evoked by odors associated with early-life toxic insults.
Method: Toxic exposure to antimycin (AM) or paraquat (PQ) was employed in E. coli OP50 food source for 24 hours from hatching. Molecular cytoprotective responses were monitored by, visualizing the hsp-6::GFP mitochondrial stress marker and gst-4::GFP detoxification enzyme reporters expression. Behavioral responses were assayed by chemotaxis tests.
Results: Both AM and PQ in early life resulted in food-source aversion, developmental retardation and hsp-6::GFP and gst-4::GFP reporter induction, respectively. Intriguingly, worms that remained on food lawn exhibited higher expression of both cytoprotective molecular markers. AM and PQ treated L2 larvae exhibited an aversive associative memory to OP50 sensory cues and an increased preference for previously not encountered B.subtilis bacteria. However, persistence of AM and PQ induced behaviors in adulthood remained elusive. Nonetheless, in response to early-life toxin-exposure a re-encounter of adults with OP50 sensory cues alone increased the expression of hsp-6::GFP or gst-4::GFP reporters.
Conclusion: Perinatal toxic insults associated sensory cues trigger a complementary pattern of cytoprotective and early learned aversive responses as well as a re-activation of toxin-induced molecular defenses in adulthood. To our knowledge, this is the first demonstration of an imprinted „cellular memory” as well as an imprinted response to perceived danger.
Doctoral School: Molecular Medicine
Supervisor: Dr. Csaba Sőti