Role in Diuresis of a Calcitonin Receptor (GPRCAL1) Expressed in a Distal-Proximal Gradient in Renal Organs of the Mosquito Aedes aegypti (L.) (original) (raw)
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Insect Biochemistry and Molecular Biology, 2013
Evolution of anthropophilic hematophagy in insects resulted in the coordination of various physiological processes for survival. In female mosquitoes, a large blood meal provides proteins for egg production and as a trade-off, rapid elimination of the excess water and solutes (Na + , Cl 2 ) is critical for maintaining homeostasis and removing excess weight to resume flight and avoid predation. This post-prandial excretion is achieved by the concerted action of multiple hormones. Diuresis and natriuresis elicited by the calcitonin-like diuretic hormone 31 (DH 31 ) are believed to be mediated by a yet uncharacterized calcitonin receptor (GPRCAL) in the mosquito Malpighian tubules (MTs), the renal organs. To contribute knowledge on endocrinology of mosquito diuresis we cloned GPRCAL1 from MT cDNA. This receptor is the ortholog of the DH 31 receptor from Drosophila melanogaster that is expressed in principal cells of the fruit fly MT. Immunofluorescence similarly showed AaegGPRCAL1 is present in MT principal cells in A. aegypti, however, exhibiting an overall gradient-like pattern along the tubule novel for a GPCR in insects. Variegated, cell-specific receptor expression revealed a subpopulation of otherwise phenotypically similar principal cells. To investigate the receptor contribution to fluid elimination, RNAi was followed by urine measurement assays. In vitro, MTs from females that underwent AaegGPRcal1 knock-down exhibited up to 57% decrease in the rate of fluid secretion in response to DH 31 . Live females treated with AaegGPRcal1 dsRNA exhibited 30% reduction in fluid excreted after a blood meal. The RNAi-induced phenotype demonstrates the critical contribution of this single secretin-like family B GPCR to fluid excretion in invertebrates and highlights its relevance for the blood feeding adaptation. Our results with the mosquito AaegGPRCAL1 imply that the regulatory function of calcitonin-like receptors for ion and fluid transport in renal organs arose early in evolution.
Insect Molecular Biology, 2008
In the mosquito Aedes aegypti (L.), the molecular endocrine mechanisms underlying rapid water elimination upon eclosion and blood feeding are not fully understood. The genome contains a single predicted diuretic hormone 44 (DH 44 ) gene, but two DH 44 receptor genes. The identity of the DH 44 receptor(s) in the Malpighian tubule is unknown in any mosquito species. We show that VectorBase gene ID AAEL008292 encodes the DH 44 receptor (GPRDIH1) most highly expressed in Malpighian tubules. Sequence analysis and transcript localization indicate that AaegGPRDIH1 is the coorthologue of the Drosophila melanogaster DH 44 receptor (CG12370-PA). Time-course quantitative PCR analysis of Malpighian tubule cDNA revealed AaegGPRDIH1 expression changes paralleling periods of excretion. This suggests that target tissue receptor biology is linked to the known periods of release of diuretic hormones from the nervous system pointing to a common up-stream regulatory mechanism. Figure 2. (A) Open reading frame (ORF) alignment of dipteran DH 44 receptors: Aedes aegypti GPRDIH1 (EU273351) and GPRDIH2 (EU273352); Culex quinquefasciatus GPRDIH1 (BK006347) and GPRDIH2 (BK006348); Anopheles gambiae GPRDIH1 (AGAP005464-PA) and GPRDIH2 (AGAP005465-PA); Drosophila melanogaster CG12370-PA and CG8422-PA. Sequence identifiers are to the left (longer taxon abbreviations are for clarity) and ORF residue positions are to the right of the alignment. Regions of amino acid identity among the sequences are shaded in black. BLAST analysis shows Ae. aegypti GPRDIH1 is 70.2% identical to C. quinquefasciatus GPRDIH1, 69.1% identical to An. gambiae GPRDIH1, 54.8% identical to the D. melanogaster CG12370 receptor and 63.2% identical to the CG8422 receptor. Culex and Anopheles GPRDIH2 sequence predictions are missing ~26 amino acid residues corresponding to portions of transmembrane region IV and extracellular loop III, indicated by 'X' residues in the Culex GPRDIH2 sequence at positions 237 and 238. (B) Alignment of C-terminal sequences from predicted and cloned Diptera DH 44 receptors. Three motifs are indicated (I, II, III). These motifs suggest Ae. aegypti GPRDIH1 and the Drosophila DH 44 receptor (CG12370-PA) are co-orthologues.
2019
Insect CAPA neuropeptides, which are homologs of mammalian neuromedin U, have been described in various insect species and are known to influence ion and water balance by regulating the activity of the Malpighian 'renal' tubules (MTs). A number of diuretic hormones have been shown to increase primary fluid and ion secretion by the insect MTs and, in the adult female mosquito, a calcitonin-related peptide (DH 31) also known as mosquito natriuretic peptide, increases sodium secretion at the expense of potassium to remove the excess salt load acquired upon blood-feeding. An endogenous mosquito antidiuretic hormone was recently described, having inhibitory activity against select diuretic factors and being particularly potent against DH 31-stimulated diuresis. In the present study, we have functionally deorphanized, both in vitro and in vivo, a mosquito anti-diuretic hormone receptor (AedaeADHr). Expression analysis by quantitative PCR indicates the receptor is highly enriched in the MTs, and fluorescent in situ hybridization confirms expression within principal cells. Characterization using a 1 FITC-conjugated sheep anti-rabbit immunoglobulin G (Jackson ImmunoResearch Laboratories, West 1 Grove, PA) or Alexa Fluor 488-conjugated cross-adsorbed goat anti-rabbit immunoglobulin G (Life 1
Frontiers in physiology, 2017
Introduction: The life history of Aedes aegypti presents diverse challenges to its diuretic system. During the larval and pupal life stages mosquitoes are aquatic. With the emergence of the adult they become terrestrial. This shifts the organism within minutes from an aquatic environment to a terrestrial environment where dehydration has to be avoided. In addition, female mosquitoes take large blood meals, which present an entirely new set of challenges to salt and water homeostasis. Methods: To determine differences in gene expression associated with these different life stages, we performed an RNA-seq analysis of the main diuretic tissue in A. aegypti, the Malpighian tubules. We compared transcript abundance in 4th instar larvae to that of adult females and analyzed the data with a focus on transcripts that encode proteins potentially involved in diuresis, like water and solute channels as well as ion transporters. We compared our results against the model of potassium- and sodium...
FEBS Letters, 2011
The evolution of the blood feeding adaptation in mosquitoes required hormonal coordination of multiple physiological processes (behavior, digestion, diuresis, oogenesis). The Aedes kinins (leucokinin-like neuropeptides) are involved in post blood feeding physiological processes, having diuretic and myotropic functions. To understand the in vivo contribution of the kinin receptor to overall female post-prandial fluid excretion, RNAi knockdown was followed by fluid secretion assays which proved its fundamental role in rapid diuresis. The Aedes kinin receptor was also localized in several tissues not previously reported in mosquitoes. Results highlight the integrative role of the Aedes kinins in the success of the blood feeding adaptation.
A dynamic paracellular pathway serves diuresis in mosquito Malpighian tubules
Annals of the New York Academy of Sciences, 2012
Female mosquitoes gorge on vertebrate blood, a rich nutrient source for developing eggs. But gorging meals increase the risk of predation. Mosquitoes are quick to reduce the flight payload with a potent diuresis. Diuretic peptides of the insect kinin family induce a tenfold-reduction in the paracellular resistance of Malpighian tubules and increase the paracellular permeation of Cl − , the counterion of the transepithelial secretion of Na + and K +. As a result, the transepithelial secretion of NaCl and KCl and water increases. Insect kinins signal to the opening of the paracellular pathway via G protein-coupled receptors and the elevation of intracellular [Ca 2+ ], which leads to the reorganization of the cytoskeleton associated with the septate junction. The reorganization may affect the septate junctional proteins that control the barrier and permselectivity properties of the paracellular pathway. The proteins involved in the embryonic formation of the septate junction and in epithelial polarization are largely known for ectodermal epithelia, but the proteins that form and mediate the dynamic functions of the septate junction in Malpighian tubules remain to be determined.
Proceedings of the National Academy of Sciences, 2010
Diuresis following blood-gorging in Rhodnius prolixus is the major process leading to the transmission of Chagas' disease. We have cloned the cDNA of the first receptor known to be involved in an antidiuretic strategy in insects, a strategy that prevents diuresis. This receptor belongs to the insect CAPA receptor family known in other insects to be activated by peptides encoded within the capability gene. We characterize the expression profile in fifthinstars and find expression is localized to the alimentary canal. Highest transcript levels are found in Malpighian tubules and the anterior midgut, which are known targets of the antidiuretic hormone, RhoprCAPA-α2. Two transcripts were identified, capa-r1 and capa-r2; however, the latter encodes an atypical G proteincoupled receptor lacking a region ranging between the first and second transmembrane domain. Our heterologous expression assay revealed the expressed capa-r1 receptor is activated by Rhopr-CAPA-α2 (EC 50 = 385nM) but not by RhoprCAPA-α1. Structural analogs of the inactive RhoprCAPA-α1 were capable of activating the expressed capa-r1 receptor, confirming the importance of the C-terminal consensus sequence common to CAPA-related peptides. In addition, this receptor has some sensitivity to the pyrokininrelated peptide, RhoprCAPA-αPK1, but with an efficacy ≈40-fold less than RhoprCAPA-α2. Other peptides belonging to the PRXamide superfamily were inactive on the capa-r1 receptor. Taken together, the neuroendocrinological relevance of this receptor in facilitating the antidiuretic strategy in R. prolixus may make this receptor a useful target for development of agonists or antagonists that could help influence the transmission of Chagas' disease that occurs during diuresis in this medically important insectdisease vector.
FEBS Letters, 2011
The evolution of the blood feeding adaptation in mosquitoes required hormonal coordination of multiple physiological processes (behavior, digestion, diuresis, oogenesis). The Aedes kinins (leucokinin-like neuropeptides) are involved in post blood feeding physiological processes, having diuretic and myotropic functions. To understand the in vivo contribution of the kinin receptor to overall female post-prandial fluid excretion, RNAi knockdown was followed by fluid secretion assays which proved its fundamental role in rapid diuresis. The Aedes kinin receptor was also localized in several tissues not previously reported in mosquitoes. Results highlight the integrative role of the Aedes kinins in the success of the blood feeding adaptation.
Transport mechanisms of diuresis in Malpighian tubules of insects
Journal of Experimental Biology, 2003
SUMMARYWe have studied Malpighian tubules of Aedes aegypti using a variety of methods: Ramsay fluid secretion assay, electron probe analysis of secreted fluid, in vitro microperfusion and two-electrode voltage clamp. Collectively, these methods have allowed us to elucidate transepithelial transport mechanisms under control conditions and in the presence of diuretic peptides. Mosquito natriuretic peptide (MNP), a corticotropin-releasing factor (CRF)-like diuretic peptide, selectively increases transepithelial secretion of NaCl and water, meeting the NaCl loads of the blood meal. The intracellular messenger of MNP is cAMP, which increases the Na+ conductance and activates the Na+/K+/2Cl--cotransporter in the basolateral membrane of principal cells. Leucokinin non-selectively increases transepithelial NaCl and KCl secretion, which may deal with hemolymph volume expansions or reduce the flight pay load upon eclosion from the aquatic habitat. The non-selective NaCl and KCl diuresis stems...
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2010
Piermarini PM, Grogan LF, Lau K, Wang L, Beyenbach KW. A SLC4-like anion exchanger from renal tubules of the mosquito (Aedes aegypti): evidence for a novel role of stellate cells in diuretic fluid secretion. epithelial fluid secretion across the renal (Malpighian) tubule epithelium of the mosquito (Aedes aegypti) is energized by the vacuolartype (V-type) H ϩ -ATPase and not the Na ϩ -K ϩ -ATPase. Located at the apical membrane of principal cells, the V-type H ϩ -ATPase translocates protons from the cytoplasm to the tubule lumen. Secreted protons are likely to derive from metabolic H 2CO3, which raises questions about the handling of HCO 3