Caenorhabditis elegansprocesses sensory information to choose between freeloading and self-defense strategies

Abstract

<jats:title>Abstract</jats:title><jats:p>Hydrogen peroxide is the preeminent chemical weapon that organisms use for combat. Individual cells rely on conserved defenses to prevent and repair peroxide-induced damage, but whether similar defenses might be coordinated across cells in animals remains poorly understood. Here, we identify a neuronal circuit in the nematode <jats:italic>Caenorhabditis elegans</jats:italic> that processes information perceived by two sensory neurons to control the induction of hydrogen-peroxide defenses in the organism. We found that catalases produced by <jats:italic>Escherichia coli</jats:italic>, the nematode’s food source, can deplete hydrogen peroxide from the local environment and thereby protect the nematodes. In the presence of <jats:italic>E. coli</jats:italic>, the nematode’s neurons signal via TGFβ-insulin/IGF1 relay to target tissues to repress expression of catalases and other hydrogen-peroxide defenses. This adaptive strategy is the first example of a multicellular organism modulating its defenses when it expects to freeload from the protection provided by molecularly orthologous defenses from another species.</jats:p>

The heat shock transcription factor HSF-1 protects Caenorhabditis elegans from peroxide stress

“…During adulthood, nematodes were cultured and then assayed for survival on plates with 10 μg/ml 5-fluoro-2-deoxyuridine (Sigma), to avoid vulval rupture [27] and eliminate live progeny. Survival to 6mM or 10 mM tert-butyl hydroperoxide (Sigma) was determined on day 2 adults using a C. elegans lifespan machine scanner cluster [28] as described [29]. Survival curves were calculated using the Kaplan-Meier method.…”