The mechanoreceptor DEG‐1 regulates cold tolerance in Caenorhabditis elegans

Abstract

Caenorhabditis elegans mechanoreceptors located in ASG sensory neurons have been found to sense ambient temperature, which is a key trait for animal survival. Here, we show that experimental loss of xanthine dehydrogenase (XDH‐1) function in AIN and AVJ interneurons results in reduced cold tolerance and atypical neuronal response to changes in temperature. These interneurons connect with upstream neurons such as the mechanoreceptor‐expressing ASG. Ca2+ imaging revealed that ASG neurons respond to warm temperature via the mechanoreceptor DEG‐1, a degenerin/epithelial Na+ channel (DEG/ENaC), which in turn affects downstream AIN and AVJ circuits. Ectopic expression of DEG‐1 in the ASE gustatory neuron results in the acquisition of warm sensitivity, while electrophysiological analysis revealed that DEG‐1 and human MDEG1 were involved in warm sensation. Taken together, these results suggest that cold tolerance is regulated by mechanoreceptor‐mediated circuit calculation.

OSM-9 and OCR-2 TRPV channels are accessorial warm receptors in Caenorhabditis elegans temperature acclimatisation

“…To investigate whether TRPVs are capable of conferring thermal sensitivity to warm stimuli, we expressed OSM-9 and OCR-2 TRPVs in the right ASE (ASER) gustatory neuron. ASER was used because it is a non-warmth-sensing neuron that has previously been used in reconstitution analysis to measure temperature sensitivities of novel temperature receptors, such as rGCs and a degenerin/epithelial Na + channel-type mechanoreceptor involved in thermotaxis and cold tolerance, respectively 7 , 13 . ASER acts as a cool-sensing neuron in which GLR-3, a kainate-type glutamate receptor, functions as a cool-sensing receptor 8 .…”

“…5 a, OSM-9 OCR-2). A previous report showed that OSM-9, OCR-1, and OCR-2 cooperatively control thermosensory activity in C. elegans , with OCR-1 acting as a negative regulator of TRPV channels 13 , 16 , although it remains unclear whether OCR-1 forms a heterochannel complex with OSM-9 and OCR-2. A warm stimulus (~ 36 °C) evoked detectable inward currents in Xenopus oocytes simultaneously injected with osm-9 , ocr-2, and ocr-1 cRNA (Fig.…”

“…osm-9 and ocr-2 single mutants, the osm-9 ocr-2 double mutant, and osm-9 ocr-2; ocr-1 triple mutant expressing YC3.60 in ADL were constructed as previously described 15 . A C. elegans codon-optimised G-CaMP8 driven by the flp-6 promoter was used as a genetically encoded Ca 2+ indicator for Ca 2+ imaging of ASER neuron 13 . pMIU34 flp-6p::CeG-CaMP8 and pKOB006 gcy-5p::tagRFP was expressed in a glr-3 mutant lacking the cold-sensitive kainate-type glutamate receptor in ASER .…”

“…Previously, YC3.60 was used for Ca 2+ imaging of thermosensory neurons regulating cold tolerance, such as ADL 5 , 12 , 15 . GCaMP8.0 was used for ectopic expression analysis of ASER in Takagaki et al 13 because the Ca 2+ sensitivity of GCaMP8.0 is higher than YC3.60. When we carried out the analyses for Fig.…”

Temperature sensation in cold acclimation of nematode <i>Caenorhabditis elegans</i> is affected by environmental oxygen concentration

“…。 著者らは，行動に依存しない神経回路情報処理の実験系 として線虫の「低温耐性現象」を指標に解析を行ってきた。 低温耐性とは，25 ℃で飼育した線虫を２℃に移すと死滅す るのに対し，15 ℃で飼育した線虫を２℃に移しても生存で きる現象である。さらに，25 ℃で飼育した個体を，わずか ３-５時間15 ℃に置くことで2 ℃でも生存できるようにな る低温馴化現象も見つかってきた 18,19,28) (図１) 。 低温耐性における温度応答メカニズムの分子・組織機構 は少しずつ明らかになってきている 11,17,18,22,24,27,29)…”