TY - JOUR
T1 - GAP junctions and NCA cation channels are critical for developmentally timed sleep and arousal in caenorhabditis elegans
AU - Huang, Huiyan
AU - Hayden, Dustin J.
AU - Zhu, Chen Tseh
AU - Bennett, Heather L.
AU - Venkatachalam, Vivek
AU - Skuja, Lukas L.
AU - Hart, Anne C.
N1 - Funding Information:
We thank Mei Zhen (Lunenfeld–Tanenbaum Research Institute) and Dong Yan (Duke University) for numerous constructs and strains, Gary Silverman and Stephen Pak (Washington University in St. Louis) and Barry Connors (Brown University) for manuscript discussion, and Aravinthan Samuel (Harvard University) for critical advice and support. Some strains were provided by the Caenorhabditis Genetics Center, funded by National Institutes of Health Office of Research Infrastructure Programs (grant P40 OK010440). We acknowledge support from the Brown Institute for Brain Science/Norman Prince Neurosciences Institute (BIBS/NPNI) Postdoctoral Fellowship in Translational Neuroscience (to H.H.), Karen T. Romer Undergraduate Teaching and Research Awards (to D.J.H. and L.L.S.), Burroughs Wellcome Fund Career Award (to V.V.) and National Institute of Neurological Disorders and Stroke (NINDS) grant NS055813 (to A.C.H.).
Funding Information:
We thank Mei Zhen (Lunenfeld–Tanenbaum Research Insti-tute) and Dong Yan (Duke University) for numerous constructs and strains, Gary Silverman and Stephen Pak (Washington University in St. Louis) and Barry Connors (Brown University) for manuscript discussion, and Aravinthan Samuel (Harvard University) for critical advice and support. Some strains were provided by the Caenorhabditis Genetics Center, funded by National Institutes of Health Office of Research Infrastructure Programs (grant P40 OK010440). We acknowledge support from the Brown Institute for Brain Science/Norman Prince Neurosciences Institute (BIBS/NPNI) Postdoctoral Fellowship in Translational Neuroscience (to H.H.), Karen T. Romer Undergraduate Teaching and Research Awards (to D.J.H. and L.L.S.), Burroughs Wellcome Fund Career Award (to V.V.) and National Institute of Neurological Disorders and Stroke (NINDS) grant NS055813 (to A.C.H.).
Publisher Copyright:
© 2018 by the Genetics Society of America.
PY - 2018/12
Y1 - 2018/12
N2 - An essential characteristic of sleep is heightened arousal threshold, with decreased behavioral response to external stimuli. The molecular and cellular mechanisms underlying arousal threshold changes during sleep are not fully understood. We report that loss of UNC-7 or UNC-9 innexin function dramatically reduced sleep and decreased arousal threshold during developmentally timed sleep in Caenorhabditis elegans. UNC-7 function was required in premotor interneurons and UNC-9 function was required in motor neurons in this paradigm. Simultaneous transient overexpression of UNC-7 and UNC-9 was sufficient to induce anachronistic sleep in adult animals. Moreover, loss of UNC-7 or UNC-9 suppressed the increased sleep of EGL-4 gain-of-function animals, which have increased cyclic-GMP–dependent protein kinase activity. These results suggest C. elegans gap junctions may act downstream of previously identified sleep regulators. In other paradigms, the NCA cation channels act upstream of gap junctions. Consistent with this, diminished NCA channel activity in C. elegans robustly increased arousal thresholds during sleep bouts in L4-to-adult developmentally timed sleep. Total time in sleep bouts was only modestly increased in animals lacking NCA channel auxiliary subunit UNC-79, whereas increased channel activity dramatically decreased sleep. Loss of EGL-4 or innexin proteins suppressed UNC-79 loss-of-function sleep and arousal defects. In Drosophila, the ion channel narrow abdomen, an ortholog of the C. elegans NCA channels, drive the pigment dispersing factor (PDF) neuropeptide release, regulating circadian behavior. However, in C. elegans, we found that loss of the PDF receptor PDFR-1 did not suppress gain-of-function sleep defects, suggesting an alternative downstream pathway. This study emphasizes the conservation and importance of neuronal activity modulation during sleep, and unequivocally demonstrates that gap junction function is critical for normal sleep.
AB - An essential characteristic of sleep is heightened arousal threshold, with decreased behavioral response to external stimuli. The molecular and cellular mechanisms underlying arousal threshold changes during sleep are not fully understood. We report that loss of UNC-7 or UNC-9 innexin function dramatically reduced sleep and decreased arousal threshold during developmentally timed sleep in Caenorhabditis elegans. UNC-7 function was required in premotor interneurons and UNC-9 function was required in motor neurons in this paradigm. Simultaneous transient overexpression of UNC-7 and UNC-9 was sufficient to induce anachronistic sleep in adult animals. Moreover, loss of UNC-7 or UNC-9 suppressed the increased sleep of EGL-4 gain-of-function animals, which have increased cyclic-GMP–dependent protein kinase activity. These results suggest C. elegans gap junctions may act downstream of previously identified sleep regulators. In other paradigms, the NCA cation channels act upstream of gap junctions. Consistent with this, diminished NCA channel activity in C. elegans robustly increased arousal thresholds during sleep bouts in L4-to-adult developmentally timed sleep. Total time in sleep bouts was only modestly increased in animals lacking NCA channel auxiliary subunit UNC-79, whereas increased channel activity dramatically decreased sleep. Loss of EGL-4 or innexin proteins suppressed UNC-79 loss-of-function sleep and arousal defects. In Drosophila, the ion channel narrow abdomen, an ortholog of the C. elegans NCA channels, drive the pigment dispersing factor (PDF) neuropeptide release, regulating circadian behavior. However, in C. elegans, we found that loss of the PDF receptor PDFR-1 did not suppress gain-of-function sleep defects, suggesting an alternative downstream pathway. This study emphasizes the conservation and importance of neuronal activity modulation during sleep, and unequivocally demonstrates that gap junction function is critical for normal sleep.
KW - CGMP-dependent kinase
KW - Caenorhabditis elegans sleep
KW - Gap junction
KW - NCA channel
UR - http://www.scopus.com/inward/record.url?scp=85058398073&partnerID=8YFLogxK
U2 - 10.1534/genetics.118.301551
DO - 10.1534/genetics.118.301551
M3 - Article
C2 - 30323068
AN - SCOPUS:85058398073
SN - 0016-6731
VL - 210
SP - 1369
EP - 1381
JO - Genetics
JF - Genetics
IS - 4
ER -