Dutta Soumi, Hering Lars, Grollmann Milena M, Metzendorf Niklas, Gross Vladimir, Arakawa Kazuharu, Neupert Susanne, Stengl Monika, Herberg Friedrich W, Mayer Georg
Department of Zoology, University of Kassel, Kassel, Germany.
Graduate School "Multiscale Clocks", University of Kassel, Kassel, Germany.
Open Biol. 2025 Mar;15(3):240242. doi: 10.1098/rsob.240242. Epub 2025 Mar 5.
Pigment-dispersing factors (PDFs) are neuropeptides that play key roles in controlling the circadian rhythms in various insects, whereas their function remains elusive in other protostomes including tardigrades (water bears). Here we show that the three PDFs of the tardigrade are co-localized in two pairs of inner lobe cells in the brain, whereas only one PDF occurs in four additional cerebral and two extracerebral cells. The axons of the inner lobe cells pass through the contralateral brain hemisphere, descend to the ventral nerve cord and terminate in two pairs of potential release sites in the posteriormost trunk ganglion. Using assays, we demonstrate that all three PDFs and their deorphanized receptor (PDFR) are functional. Widespread localization of PDFR suggests that tardigrade PDFs may act as multifunctional hormones and neuromodulators that control major functions including light detection, neural processing, locomotion, feeding, digestion, osmoregulation, growth, embryonic development and oogenesis/reproduction.
色素分散因子（PDFs）是一类神经肽，在控制各种昆虫的昼夜节律中起关键作用，而在包括缓步动物（水熊虫）在内的其他原口动物中，其功能仍然不明。在此我们表明，缓步动物的三种PDFs共定位于大脑中的两对内叶细胞中，而在另外四个脑内细胞和两个脑外细胞中仅出现一种PDF。内叶细胞的轴突穿过对侧脑半球，向下延伸至腹神经索，并终止于最末端躯干神经节中的两对潜在释放位点。通过实验分析，我们证明所有三种PDFs及其去孤儿化受体（PDFR）均具有功能。PDFR的广泛定位表明，缓步动物的PDFs可能作为多功能激素和神经调节剂，控制包括光检测、神经处理、运动、摄食、消化、渗透调节、生长、胚胎发育以及卵子发生/繁殖等主要功能。
