Cannell Elizabeth, Dornan Anthony J, Halberg Kenneth A, Terhzaz Selim, Dow Julian A T, Davies Shireen-A
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK; Section of Cell- and Neurobiology, Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark.
Peptides. 2016 Jun;80:96-107. doi: 10.1016/j.peptides.2016.02.004. Epub 2016 Feb 17.
Malpighian tubules are critical organs for epithelial fluid transport and stress tolerance in insects, and are under neuroendocrine control by multiple neuropeptides secreted by identified neurons. Here, we demonstrate roles for CRF-like diuretic hormone 44 (DH44) and Drosophila melanogaster kinin (Drome-kinin, DK) in desiccation and starvation tolerance. Gene expression and labelled DH44 ligand binding data, as well as highly selective knockdowns and/or neuronal ablations of DH44 in neurons of the pars intercerebralis and DH44 receptor (DH44-R2) in Malpighian tubule principal cells, indicate that suppression of DH44 signalling improves desiccation tolerance of the intact fly. Drome-kinin receptor, encoded by the leucokinin receptor gene, LKR, is expressed in DH44 neurons as well as in stellate cells of the Malpighian tubules. LKR knockdown in DH44-expressing neurons reduces Malpighian tubule-specific LKR, suggesting interactions between DH44 and LK signalling pathways. Finally, although a role for DK in desiccation tolerance was not defined, we demonstrate a novel role for Malpighian tubule cell-specific LKR in starvation tolerance. Starvation increases gene expression of epithelial LKR. Also, Malpighian tubule stellate cell-specific knockdown of LKR significantly reduced starvation tolerance, demonstrating a role for neuropeptide signalling during starvation stress.
马尔皮基氏小管是昆虫上皮液体运输和应激耐受性的关键器官，受特定神经元分泌的多种神经肽的神经内分泌控制。在此，我们证明了类促肾上腺皮质激素利尿激素44（DH44）和果蝇激肽（Drome-激肽，DK）在耐干燥和耐饥饿方面的作用。基因表达和标记的DH44配体结合数据，以及在脑间部神经元中对DH44进行高度选择性敲低和/或神经元消融，以及在马尔皮基氏小管主细胞中对DH44受体（DH44-R2）进行敲低，表明抑制DH44信号传导可提高完整果蝇的耐干燥能力。由亮氨酸激肽受体基因LKR编码的激肽受体在DH44神经元以及马尔皮基氏小管的星状细胞中表达。在表达DH44的神经元中敲低LKR会降低马尔皮基氏小管特异性LKR，这表明DH44和亮氨酸激肽信号通路之间存在相互作用。最后，虽然未明确DK在耐干燥能力中的作用，但我们证明了马尔皮基氏小管细胞特异性LKR在耐饥饿方面的新作用。饥饿会增加上皮LKR的基因表达。此外，在马尔皮基氏小管星状细胞中特异性敲低LKR会显著降低耐饥饿能力，这表明神经肽信号在饥饿应激期间发挥作用。
