A sleep-active neuron can promote survival while sleep behavior is disturbed.

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Sleep neurons are crucial for physiological restoration and survival.
• The specific mechanisms by which sleep neurons link sleep behavior to survival remain unclear.
• The Caenorhabditis elegans RIS neuron is a sleep-active neuron essential for survival during starvation and wounding.

Purpose of the Study:

• To investigate whether the sleep-active RIS neuron promotes survival primarily through sleep behavior or via an independent mechanism.
• To differentiate the roles of RIS neuron activity in controlling sleep behavior versus survival during starvation.

Main Methods:

• Utilized genetic manipulation in Caenorhabditis elegans to alter RIS neuron activity using constitutively active potassium and sodium channel mutant alleles.
• Employed calcium imaging to monitor RIS neuron activity.
• Used optogenetics and blue-light stimulation to manipulate sleep and RIS activity.
• Investigated the role of FLP-11 neuropeptides in RIS function.

Main Results:

• Altering RIS neuron activity with unc-58gf led to a loss of sleep behavior but increased survival.
• Constant high-level RIS activation, induced by genetic manipulation or optogenetics, enhanced survival independent of sleep.
• Blue-light stimulation, which disrupts sleep, also overactivated RIS and increased survival.
• FLP-11 neuropeptides were found to be important for both sleep induction and starvation survival.

Conclusions:

• The promotion of sleep behavior and survival are separable functions of the RIS neuron.
• These functions, while often coupled, can be uncoupled under conditions of strong RIS activation or impaired sleep.
• The RIS neuron can confer survival benefits even when behavioral sleep is compromised, suggesting a general role for sleep neurons in promoting survival during stress.