Characterization of a set of abdominal neuroendocrine cells that regulate stress physiology using colocalized diuretic peptides in Drosophila

Abstract

Multiple neuropeptides are known to regulate water and ion balance in Drosophila melanogaster. Several of these peptides also have other functions in physiology and behavior. Examples are corticotropin-releasing factor-like diuretic hormone (diuretic hormone 44; DH44) and leucokinin (LK), both of which induce fluid secretion by Malpighian tubules (MTs), but also regulate stress responses, feeding, circadian activity and other behaviors. Here, we investigated the functional relations between the LK and DH44 signaling systems. DH44 and LK peptides are only colocalized in a set of abdominal neurosecretory cells (ABLKs). Targeted knockdown of each of these peptides in ABLKs leads to increased resistance to desiccation, starvation and ionic stress. Food ingestion is diminished by knockdown of DH44, but not LK, and water retention is increased by LK knockdown only. Thus, the two colocalized peptides display similar systemic actions, but differ with respect to regulation of feeding and body water retention. We also demonstrated that DH44 and LK have additive effects on fluid secretion by MTs. It is likely that the colocalized peptides are coreleased from ABLKs into the circulation and act on the tubules where they target different cell types and signaling systems to regulate diuresis and stress tolerance. Additional targets seem to be specific for each of the two peptides and subserve regulation of feeding and water retention. Our data suggest that the ABLKs and hormonal actions are sufficient for many of the known DH44 and LK functions, and that the remaining neurons in the CNS play other functional roles.Electronic supplementary materialThe online version of this article (doi:10.1007/s00018-017-2682-y) contains supplementary material, which is available to authorized users.

A neuroendocrine pathway modulating osmotic stress inDrosophila

“…Previously, we showed that systemic Crz signaling modulates feeding and nutritional stress through direct actions on the fat body as well as via interactions with AKH and insulinsignaling [9]. Since CrzR is highly expressed in the CNS (Figure S1), we hypothesized that 12 Crz may interact with other peptidergic signaling to maintain physiological homeostasis associated with stress. To test this assumption, we mapped the distribution of CrzR expression in adult CNS by using different CrzR-GAL4 lines to drive GFP expression.…”

“…Immunohistochemistry for D. melanogaster adult CNS and gut was performed as described earlier [12]. Briefly, tissues were dissected in phosphate buffered saline (PBS), fixed in 5% ice-cold paraformaldehyde (3.5 -4 hours), washed in PBS and incubated in primary antibodies ( Table 2) diluted in PBS with 0.5% Triton X (PBST) for 48 hours at 4°C.…”

“…These flies were then processed for immunohistochemistry as described above. Cell fluorescence was quantified as described previously [12]. Note that the anti-PVK-2 antibody used to quantify CAPA peptide levels cross-reacts with other PRXamide-related peptides.…”

“…In the vinegar fly Drosophila melanogaster, several peptide hormones and neuropeptides have been shown to influence responses to nutrient and osmotic stress via actions on peripheral tissues such as the liver-like fat body and Malpighian (renal) tubules that are analogous to the mammalian kidneys. These hormones include Drosophila insulin-like peptides (DILPs), adipokinetic hormone (AKH), corazonin (Crz), leucokinin, diuretic hormone 44 (DH44) and capability gene-derived CAPA peptides [1][2][3][4][5][6][7][8][9][10][11][12]. In mammals, the hypothalamic-pituitary-adrenal (HPA) axis coordinates stress responses via the sequential secretion of corticotropinreleasing factor (CRF), adrenocorticotropic hormone (ACTH) and cortisol [13][14][15].…”

Assessment of neuropeptide binding sites and the impact of biostable kinin and CAP2b analogue treatment on aphid (Myzus persicae and Macrosiphum rosae) stress tolerance

“…Insect kinins are multifunctional neuropeptides which share a conserved C-terminal pentapeptide motif Phe-X 1 -X 2 -Trp-Gly-NH2, where X 1 can be His, Asn, Ser or Tyr, and X 2 can be Ser, Pro or Ala. 6 The insect kinins have been identified in most insects, with the exception of Coleoptera, 7 and have diverse roles in the stimulation of muscle, 8 fluid secretion in renal tubules, 9,10 digestive enzyme release, 11 inhibition of larval weight gain 12 and the desiccation and starvation stress response. 13,14 The second family, the CAPA peptides, were first identified from the moth Manduca sexta (CAP2b) 15 and have since been identified in many insect families. 16 Although function varies depending on insect species, life stage, and lifestyle, CAPA peptides play a key role in myomodulation and osmoregulation 16 and have more recently been linked to desiccation and cold tolerance in Drosophila species.…”