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O2-Dependent Protein Internalization Underlies Astrocytic Sensing of Acute Hypoxia by Restricting Multimodal TRPA1 Channel Responses

Authors :
Alexander J. Stokes
Akito Nakao
Isato Fukushi
Ha Nam Tran
Yasumasa Okada
Yasuo Mori
Reiko Sakaguchi
Tomohiro Numata
Kotaro Takeda
Nobuaki Takahashi
Seishiro Sawamura
Tatsuki Kurokawa
Makoto Uchiyama
Maximilian C. C. J. C. Ebert
Yuki Kurita
Source :
Current Biology. 30:3378-3396.e7
Publication Year :
2020
Publisher :
Elsevier BV, 2020.

Abstract

Summary Hypoxia sensors are essential for regulating local oxygen (O2) homeostasis within the body. This is especially pertinent within the CNS, which is particularly vulnerable to O2 deprivation due to high energetic demand. Here, we reveal hypoxia-monitoring function exerted by astrocytes through an O2-regulated protein trafficking mechanism within the CNS. Strikingly, cultured mouse astrocytes isolated from the parafacial respiratory group (pFRG) and retrotrapezoid nucleus (RTN) region are capable of rapidly responding to moderate hypoxia via the sensor cation channel transient receptor potential (TRP) A1 but, unlike multimodal sensory neurons, are inert to hyperoxia and other TRPA1 activators (carbon dioxide, electrophiles, and oxidants) in normoxia. Mechanistically, O2 suppresses TRPA1 channel activity by protein internalization via O2-dependent proline hydroxylation and subsequent ubiquitination by an E3 ubiquitin ligase, NEDD4-1 (neural precursor cell-expressed developmentally down-regulated protein 4). Hypoxia inhibits this process and instantly accumulates TRPA1 proteins at the plasma membrane, inducing TRPA1-mediated Ca2+ influx that triggers ATP release from pFRG/RTN astrocytes, potentiating respiratory center activity. Furthermore, astrocyte-specific Trpa1 disruption in a mouse brainstem-spinal cord preparation impedes the amplitude augmentation of the central autonomic respiratory output during hypoxia. Thus, reversible coupling of the TRPA1 channels with O2-dependent protein translocation allows astrocytes to act as acute hypoxia sensors in the medullary respiratory center.

Details

ISSN :
09609822
Volume :
30
Database :
OpenAIRE
Journal :
Current Biology
Accession number :
edsair.doi...........bec9ebdeaff53cb7586a61d83e1bbbf7