期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：42
页码：E5753-E5761
DOI：10.1073/pnas.1514862112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceDiscovering new light-sensing mechanisms and cell types are of considerable interest to researchers across disciplines. Understanding how cells sense light is one of the most fundamental problems in biology. In addition, optogenetics has become a critical research tool and discovery of new light-sensing mechanisms may expand the existing toolbox. In this work, we described our discovery of a dTRPA1-dependent photochemical pathway that is sufficient to confer UV sensitivity to light-insensitive cells. We also discovered a group of neuroendocrine cells that express these isoforms endogenously and can sense UV. These findings demonstrate a new cell type that can sense strong UV and the potential of exploiting dTRPA1 channel as an optogenetic tool. The transient receptor potential A1 (TRPA1) channel is an evolutionarily conserved detector of temperature and irritant chemicals. Here, we show that two specific isoforms of TRPA1 in Drosophila are H2O2 sensitive and that they can detect strong UV light via sensing light-induced production of H2O2. We found that ectopic expression of these H2O2-sensitive Drosophila TRPA1 (dTRPA1) isoforms conferred UV sensitivity to light-insensitive HEK293 cells and Drosophila neurons, whereas expressing the H2O2-insensitive isoform did not. Curiously, when expressed in one specific group of motor neurons in adult flies, the H2O2-sensitive dTRPA1 isoforms were as competent as the blue light-gated channelrhodopsin-2 in triggering motor output in response to light. We found that the corpus cardiacum (CC) cells, a group of neuroendocrine cells that produce the adipokinetic hormone (AKH) in the larval ring gland endogenously express these H2O2-sensitive dTRPA1 isoforms and that they are UV sensitive. Sensitivity of CC cells required dTRPA1 and H2O2 production but not conventional phototransduction molecules. Our results suggest that specific isoforms of dTRPA1 can sense UV light via photochemical production of H2O2. We speculate that UV sensitivity conferred by these isoforms in CC cells may allow young larvae to activate stress response--a function of CC cells--when they encounter strong UV, an aversive stimulus for young larvae.
