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Li Y, Piermarini PM. Dietary calcium (Ca 2+) impacts Ca 2+ content and molecular expression of Ca 2+-transporters in Malpighian tubules of the yellow fever mosquito, Aedes aegypti. J Insect Physiol 2023; 149:104551. [PMID: 37544474 DOI: 10.1016/j.jinsphys.2023.104551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/08/2023]
Abstract
The renal (Malpighian) tubules of insects play important roles in hemolymph Ca2+ regulation. Here we investigated how dietary Ca2+ loads from sucrose or blood meals affect the Ca2+ content and mRNA expression of Ca2+ transporters in Malpighian tubules of adult female mosquitoes. Using the yellow fever mosquito Aedes aegypti we found that feeding females 10% sucrose with elevated Ca2+ concentration ad libitum for 6 days led to increased Ca2+ content in Malpighian tubules. The increases of Ca2+ content correlated with up-regulations of mRNAs encoding intracellular Ca2+-ATPases (SERCA and SPCA), a plasma membrane Ca2+-ATPase (PMCA), and a K+-dependent Na+/Ca2+ exchanger (NCKX1). We also found that when adult females were fed blood, tubule Ca2+ content changed dynamically over the next 72 h in a manner consistent with redistribution of tubule Ca2+ stores to other tissues (e.g., ovaries). The changes in tubule Ca2+ were correlated with dynamic changes in mRNA abundances of SERCA, SPCA, PMCA, and NCKX1. Our results are the first to demonstrate that Malpighian tubules of adult female mosquitoes have a remarkable capacity to handle high dietary Ca2+ loads, most likely through the combination of storing excess Ca2+ within intracellular compartments and secreting it into the tubule lumen for excretion. Our results also suggest that the Malpighian tubules play key roles in supplying Ca2+ to other tissues during the processing of blood meals.
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Affiliation(s)
- Yuan Li
- Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, United States
| | - Peter M Piermarini
- Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, United States.
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2
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Yamamoto Y, Fujiwara Y. Calcium storage in Malpighian tubules and the putative use for pupal chamber formation in a wood-feeding insect. J Insect Physiol 2023:104534. [PMID: 37364813 DOI: 10.1016/j.jinsphys.2023.104534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 06/13/2023] [Accepted: 06/21/2023] [Indexed: 06/28/2023]
Abstract
Cerambycid beetles form a chamber to spend their pupal stages in various forms according to the species. The red-necked longhorn beetle Aromia bungii (Coleoptera: Cerambycidae), which is an invasive pest that severely damages Rosaceae trees, makes a pupal chamber at the end of a tunnel deep in the xylem. Beetle larvae and the closely related species form a calcareous lid at the entrance of a pupal chamber. Previous studies on the closely related species conducted more than century ago suggested that Malpighian tubules (MTs) play a vital role in calcium carbonate accumulation. However, the association between this Ca2+ accumulation and pupal chamber lid formation utilizing the possible calcium compounds stored in MTs have not yet been demonstrated. First, we artificially reared A. bungii larvae from eggs in host branches for 100 days and identified the larval developmental status and pupal chamber formation, using X-ray computed tomography. Second, we collected larvae from the branches and observed the internal organs by direct dissection under a microscope. Finally, we analyzed the elemental distribution, particularly calcium, in the larval gut with MTs, using energy dispersive X-ray fluorescence. The results suggest that immature larvae of A. bungii could accumulate Ca2+ in the MTs through wood tunneling and feeding activities. Ca2+ was stored at the proximal regions in two of the six MTs located posteriorly in the body. Additionally, larvae that formed a calcareous lid at the entrance of pupal chambers in the branches did not store Ca2+ in the MTs, suggesting that the larvae of A. bungii used the stored Ca2+ in their MTs for lid formation.
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Affiliation(s)
- Yuichi Yamamoto
- Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture, 442, Shakudo, Habikino, Osaka 583-0862, Japan.
| | - Yuko Fujiwara
- Laboratory of Wood Processing Division of Forestry and Biomaterials Science Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 Japan
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3
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Reynolds CJ, Turin DR, Romero MF. Transporters and tubule crystals in the insect Malpighian tubule. Curr Opin Insect Sci 2021; 47:82-89. [PMID: 34044181 PMCID: PMC8487917 DOI: 10.1016/j.cois.2021.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 05/18/2021] [Indexed: 05/16/2023]
Abstract
The insect renal (Malpighian) tubules are functionally homologous to the mammalian kidney. Accumulating evidence indicates that renal tubule crystals form in a manner similar to mammalian kidney stones. In Drosophila melanogaster, crystals can be induced by diet, toxic substances, or genetic mutations that reflect circumstances influencing or eliciting kidney stones in mammals. Incredibly, many mammalian proteins have distinct homologs in Drosophila, and the function of most homologs have been demonstrated to recapitulate their mammalian and human counterparts. Here, we discuss the present literature establishing Drosophila as a nephrolithiasis model. This insect model may be used to investigate and understand the etiology of kidney stone diseases, especially with regard to calcium oxalate, calcium phosphate and xanthine or urate crystallization.
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Affiliation(s)
- Carmen J Reynolds
- Physiology and Biomedical Engineering, Mayo Clinic College of Medicine & Science, 200 First Street SW, Rochester, MN 55905, USA
| | - Daniel R Turin
- Physiology and Biomedical Engineering, Mayo Clinic College of Medicine & Science, 200 First Street SW, Rochester, MN 55905, USA; University of Minnesota-Rochester, 111 South Broadway, Suite 300, Rochester, MN 55904, USA
| | - Michael F Romero
- Physiology and Biomedical Engineering, Mayo Clinic College of Medicine & Science, 200 First Street SW, Rochester, MN 55905, USA; Nephrology and Hypertension, Mayo Clinic College of Medicine and Science, 200 First Street SW, Rochester, MN 55905, USA.
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4
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Martín-Vega D, Clark B, Ferrer LM, López-Tamayo S, Panadero R, Cepeda-Palacios R, Colwell DD, Hall MJR. Major differences in the larval anatomy of the digestive and excretory systems of three Oestridae species revealed by micro-CT. Med Vet Entomol 2021; 35:106-120. [PMID: 32896916 DOI: 10.1111/mve.12476] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/21/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Oestrid flies (Diptera: Oestridae) do not feed during the adult stage, so they depend on an efficient assimilation and storage of nutrients during their parasitic larval stage. We describe the general morphology and provide volumetric data for the digestive and excretory organs of the three larval instars of the nasal bot fly Oestrus ovis L., using micro-computed tomography. The size of the digestive and excretory organs greatly increased across larval instars. In all instars, the two salivary glands were remarkably large and formed a 'glandular band' by coming together, but without lumina uniting, at their posterior ends. The distal region of the anterior Malpighian tubules was greatly enlarged and full of highly radio-opaque concretions. Moreover, the anatomy of O. ovis third-instar larva was compared to that of two species of, respectively, similar and different feeding habits: Cephenemyia stimulator (Clark) and Hypoderma actaeon Brauer. Whereas the general morphology and arrangement of the digestive and excretory systems of C. stimulator was similar to that of O. ovis, some differences were observed in H. actaeon: a swollen anterior region of the midgut, salivary glands shorter and not forming a 'band' and anterior Malpighian tubules narrowly uniform throughout their entire length.
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Affiliation(s)
- D Martín-Vega
- Department of Life Sciences, University of Alcalá, Alcalá de Henares, Spain
- Department of Life Sciences, Natural History Museum, London, U.K
| | - B Clark
- Imaging and Analysis Centre, Natural History Museum, London, U.K
| | - L M Ferrer
- Department of Animal Pathology, University of Zaragoza, Zaragoza, Spain
| | - S López-Tamayo
- Department of Animal Pathology, University of Zaragoza, Zaragoza, Spain
| | - R Panadero
- Department of Animal Pathology, University of Santiago de Compostela, Lugo, Spain
| | - R Cepeda-Palacios
- Department of Animal Science and Environment Preservation, Autonomous University of Baja California Sur, La Paz, Mexico
| | - D D Colwell
- Agriculture and Agri-Food Canada, Lethbridge, Canada
| | - M J R Hall
- Department of Life Sciences, Natural History Museum, London, U.K
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5
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Orchard I, Leyria J, Al-Dailami A, Lange AB. Fluid Secretion by Malpighian Tubules of Rhodnius prolixus: Neuroendocrine Control With New Insights From a Transcriptome Analysis. Front Endocrinol (Lausanne) 2021; 12:722487. [PMID: 34512553 PMCID: PMC8426621 DOI: 10.3389/fendo.2021.722487] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/03/2021] [Indexed: 01/25/2023] Open
Abstract
Rhodnius prolixus (the kissing bug and a major vector of Chagas disease) is an obligate blood feeder that in the case of the fifth instar consumes up to 10 times its unfed body weight in a single 20-minute feed. A post-prandial diuresis is initiated, within minutes of the start of gorging, in order to lower the mass and concentrate the nutrients of the meal. Thus, R. prolixus rapidly excretes a fluid that is high in NaCl content and hypo-osmotic to the hemolymph, thereby eliminating 50% of the volume of the blood meal within 3 hours of gorging. In R. prolixus, as with other insects, the Malpighian tubules play a critical role in diuresis. Malpighian tubules are not innervated, and their fine control comes under the influence of the neuroendocrine system that releases amines and neuropeptides as diuretic or antidiuretic hormones. These hormones act upon the Malpighian tubules via a variety of G protein-coupled receptors linked to second messenger systems that influence ion transporters and aquaporins; thereby regulating fluid secretion. Much has been discovered about the control of diuresis in R. prolixus, and other model insects, using classical endocrinological studies. The post-genomic era, however, has brought new insights, identifying novel diuretic and antidiuretic hormone-signaling pathways whilst also validating many of the classical discoveries. This paper will focus on recent discoveries into the neuroendocrine control of the rapid post-prandial diuresis in R. prolixus, in order to emphasize new insights from a transcriptome analysis of Malpighian tubules taken from unfed and fed bugs.
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6
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Abstract
PURPOSE OF REVIEW Studies of the genetic model organism, Drosophila melanogaster, have unraveled molecular pathways relevant to human physiology and disease. The Malpighian tubule, the Drosophila renal epithelium, is described here, including tools available to study transport; conserved transporters, channels, and the signaling pathways regulating them; and fly models of kidney stone disease. RECENT FINDINGS Tools to measure Malpighian tubule transport continue to advance, including use of a transgenic sensor to quantify intracellular pH and proton fluxes. A recent study generated an RNA-sequencing-based atlas of tissue-specific gene expression, with resulting insights into Malpighian tubule gene expression of transporters and channels. Advances have been made in understanding the molecular physiology of the With No Lysine kinase-Ste20-related proline/alanine rich kinase/oxidative stress response kinase cascade that regulates epithelial ion transport in flies and mammals. New studies in Drosophila kidney stone models have characterized zinc transporters and used Malpighian tubules to study the efficacy of a plant metabolite in decreasing stone burden. SUMMARY Study of the Drosophila Malpighian tubule affords opportunities to better characterize the molecular physiology of epithelial transport mechanisms relevant to mammalian renal physiology.
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7
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Murphy DT, Allen CM, Ghidan O, Dickson A, Hu W, Briggs E, Holder PW, Armstrong KF. Analysing Sr isotopes in low-Sr samples such as single insects with inductively coupled plasma tandem mass spectrometry using N 2 O as a reaction gas for in-line Rb separation. Rapid Commun Mass Spectrom 2020; 34:e8604. [PMID: 31756774 PMCID: PMC7050539 DOI: 10.1002/rcm.8604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 05/28/2023]
Abstract
RATIONALE Strontium isotopes are valuable markers of provenance in a range of disciplines. Limited amounts of Sr in low-mass samples such as insects mean that conventional Sr isotope analysis precludes their use for geographic origins in many ecological studies or in applications such as biosecurity. Here we test the viability of using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) with N2 O as a reaction gas for accurately determining Sr isotopes in insects with Sr < 100 ng. METHODS Strontium isotopes were determined in solution mode using ICP-MS/MS with 0.14 L/min N2 O as a reaction gas to convert Sr+ into SrO+ for in-line separation of 87 Sr from 87 Rb. The Sr isotope reference standards NIST SRM 987, NIST SRM 1570a and NIST SRM 1547 were used to assess accuracy and reproducibility. Ten insect species collected from the wild as a proof-of-principle application were analysed for Sr concentration and Sr isotopes. RESULTS Using ICP-MS/MS we show for the first time that internal mass bias correction of 87 Sr16 O/86 Sr16 O based on 88 Sr16 O/86 Sr16 O works to give for NIST SRM 987 a 87 Sr/86 Sr ratio of 0.7101 ± 0.012 (RSD = 0.17%) and for NIST SRM 1570a a 87 Sr/86 Sr ratio of 0.7100 ± 0.009 (RSD = 0.12%), which are within error of the accepted values. The first 87 Sr/86 Sr ratio of NIST SRM 1547 is 0.7596 ± 0.0014. Strontium analyses were run on 0.8 mL of 0.25-0.5 ppb Sr, which equates to 2-4 ng of Sr. Strontium isotope analysis with a precision of >99.8% can be achieved with in-line separation of 87 Sr from 87 Rb at least up to solutions with 25 ppb Rb. CONCLUSIONS A minimum of 5 mg of insect tissue is required for Sr isotope analysis. This new ICP-MS/MS method enables Sr isotope analysis in single insects, allowing population-scale studies to be feasible and making possible applications with time-critical uses such as biosecurity.
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Affiliation(s)
- David Thomas Murphy
- School of Earth, Environmental and Biological SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Charlotte M. Allen
- School of Earth, Environmental and Biological SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
- Institute for Future EnvironmentsQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Osama Ghidan
- Institute for Future EnvironmentsQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Andrew Dickson
- School of Earth, Environmental and Biological SciencesQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Wan‐Ping Hu
- Institute for Future EnvironmentsQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Ethan Briggs
- School of Biological SciencesUniversity of QueenslandBrisbaneQueenslandAustralia
| | - Peter W. Holder
- Bio‐Protection Research CentreLincoln UniversityLincolnNew Zealand
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8
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Cohen E, Sawyer JK, Peterson NG, Dow JAT, Fox DT. Physiology, Development, and Disease Modeling in the Drosophila Excretory System. Genetics 2020; 214:235-264. [PMID: 32029579 PMCID: PMC7017010 DOI: 10.1534/genetics.119.302289] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/04/2019] [Indexed: 02/06/2023] Open
Abstract
The insect excretory system contains two organ systems acting in concert: the Malpighian tubules and the hindgut perform essential roles in excretion and ionic and osmotic homeostasis. For over 350 years, these two organs have fascinated biologists as a model of organ structure and function. As part of a recent surge in interest, research on the Malpighian tubules and hindgut of Drosophila have uncovered important paradigms of organ physiology and development. Further, many human disease processes can be modeled in these organs. Here, focusing on discoveries in the past 10 years, we provide an overview of the anatomy and physiology of the Drosophila excretory system. We describe the major developmental events that build these organs during embryogenesis, remodel them during metamorphosis, and repair them following injury. Finally, we highlight the use of the Malpighian tubules and hindgut as accessible models of human disease biology. The Malpighian tubule is a particularly excellent model to study rapid fluid transport, neuroendocrine control of renal function, and modeling of numerous human renal conditions such as kidney stones, while the hindgut provides an outstanding model for processes such as the role of cell chirality in development, nonstem cell-based injury repair, cancer-promoting processes, and communication between the intestine and nervous system.
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Affiliation(s)
| | - Jessica K Sawyer
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, and
| | | | - Julian A T Dow
- Institute of Molecular, Cell, and Systems Biology, University of Glasgow, G12 8QQ, United Kingdom
| | - Donald T Fox
- Department of Cell Biology and
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, and
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9
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Jonusaite S, Beyenbach KW, Meyer H, Paululat A, Izumi Y, Furuse M, Rodan AR. The septate junction protein Mesh is required for epithelial morphogenesis, ion transport, and paracellular permeability in the Drosophila Malpighian tubule. Am J Physiol Cell Physiol 2020; 318:C675-C694. [PMID: 31913700 DOI: 10.1152/ajpcell.00492.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Septate junctions (SJs) are occluding cell-cell junctions that have roles in paracellular permeability and barrier function in the epithelia of invertebrates. Arthropods have two types of SJs, pleated SJs and smooth SJs (sSJs). In Drosophila melanogaster, sSJs are found in the midgut and Malpighian tubules, but the functions of sSJs and their protein components in the tubule epithelium are unknown. Here we examined the role of the previously identified integral sSJ component, Mesh, in the Malpighian tubule. We genetically manipulated mesh specifically in the principal cells of the tubule at different life stages. Tubules of flies with developmental mesh knockdown revealed defects in epithelial architecture, sSJ molecular and structural organization, and lack of urine production in basal and kinin-stimulated conditions, resulting in edema and early adult lethality. Knockdown of mesh during adulthood did not disrupt tubule epithelial and sSJ integrity but decreased the transepithelial potential, diminished transepithelial fluid and ion transport, and decreased paracellular permeability to 4-kDa dextran. Drosophila kinin decreased transepithelial potential and increased chloride permeability, and it stimulated fluid secretion in both control and adult mesh knockdown tubules but had no effect on 4-kDa dextran flux. Together, these data indicate roles for Mesh in the developmental maturation of the Drosophila Malpighian tubule and in ion and macromolecular transport in the adult tubule.
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Affiliation(s)
- Sima Jonusaite
- Division of Nephrology and Hypertension, Department of Internal Medicine, and Molecular Medicine Program, University of Utah, Salt Lake City, Utah
| | - Klaus W Beyenbach
- Division of Animal Physiology, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Heiko Meyer
- Division of Zoology and Developmental Biology, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Achim Paululat
- Division of Zoology and Developmental Biology, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany
| | - Yasushi Izumi
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI, Okazaki, Japan
| | - Mikio Furuse
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI, Okazaki, Japan
| | - Aylin R Rodan
- Division of Nephrology and Hypertension, Department of Internal Medicine, and Molecular Medicine Program, University of Utah, Salt Lake City, Utah.,Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah
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10
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Ghimire S, Terhzaz S, Cabrero P, Romero MF, Davies SA, Dow JAT. Targeted renal knockdown of Na +/H + exchanger regulatory factor Sip1 produces uric acid nephrolithiasis in Drosophila. Am J Physiol Renal Physiol 2019; 317:F930-F940. [PMID: 31364377 DOI: 10.1152/ajprenal.00551.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nephrolithiasis is one of the most common kidney diseases, with poorly understood pathophysiology, but experimental study has been hindered by lack of experimentally tractable models. Drosophila melanogaster is a useful model organism for renal diseases because of genetic and functional similarities of Malpighian (renal) tubules with the human kidney. Here, we demonstrated function of the sex-determining region Y protein-interacting protein-1 (Sip1) gene, an ortholog of human Na+/H+ exchanger regulatory factor (NHERF1), in Drosophila Malpighian tubules and its impact on nephrolithiasis. Abundant birefringent calculi were observed in Sip1 mutant flies, and the phenotype was also observed in renal stellate cell-specific RNA interference Sip1 knockdown in otherwise normal flies, confirming a renal etiology. This phenotype was abolished in rosy mutant flies (which model human xanthinuria) and by the xanthine oxidase inhibitor allopurinol, suggesting that the calculi were of uric acid. This was confirmed by direct biochemical assay for urate. Stones rapidly dissolved when the tubule was bathed in alkaline media, suggesting that Sip1 knockdown was acidifying the tubule. SIP1 was shown to collocate with Na+/H+ exchanger isoform 2 (NHE2) and with moesin in stellate cells. Knockdown of NHE2 specifically to the stellate cells also increased renal uric acid stone formation, and so a model was developed in which SIP1 normally regulates NHE2 activity and luminal pH, ultimately leading to uric acid stone formation. Drosophila renal tubules may thus offer a useful model for urate nephrolithiasis.
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Affiliation(s)
- Saurav Ghimire
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Selim Terhzaz
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Pablo Cabrero
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Shireen A Davies
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Julian A T Dow
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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11
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Davies SA, Cabrero P, Marley R, Corrales GM, Ghimire S, Dornan AJ, Dow JAT. Epithelial Function in the Drosophila Malpighian Tubule: An In Vivo Renal Model. Methods Mol Biol 2019; 1926:203-221. [PMID: 30742274 DOI: 10.1007/978-1-4939-9021-4_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The insect renal (Malpighian) tubule has long been a model system for the study of fluid secretion and its neurohormonal control, as well as studies on ion transport mechanisms. To extend these studies beyond the boundaries of classical physiology, a molecular genetic approach together with the 'omics technologies is required. To achieve this in any vertebrate transporting epithelium remains a daunting task, as the genetic tools available are still relatively unsophisticated. Drosophila melanogaster, however, is an outstanding model organism for molecular genetics. Here we describe a technique for fluid secretion assays in the D. melanogaster equivalent of the kidney nephron. The development of this first physiological assay for a Drosophila epithelium, allowing combined approaches of integrative physiology and functional genomics, has now provided biologists with an entirely new model system, the Drosophila Malpighian tubule, which is utilized in multiple fields as diverse as kidney disease research and development of new modes of pest insect control.
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Affiliation(s)
- Shireen-A Davies
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
| | - Pablo Cabrero
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Richard Marley
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Guillermo Martinez Corrales
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Saurav Ghimire
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Anthony J Dornan
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Julian A T Dow
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
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12
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Browne A, O'Donnell MJ. Mechanisms of calcium sequestration by isolated Malpighian tubules of the house cricket Acheta domesticus. Arch Insect Biochem Physiol 2018; 97:e21431. [PMID: 29159836 DOI: 10.1002/arch.21431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hemolymph calcium homeostasis in insects is achieved by the Malpighian tubules, primarily by sequestering excess Ca2+ within internal calcium stores (Ca-rich granules) most often located within type I (principal) tubule cells. Using both the scanning ion-selective electrode technique and the Ramsay secretion assay this study provides the first measurements of basolateral and transepithelial Ca2+ fluxes across the Malpighian tubules of an Orthopteran insect, the house cricket Acheta domesticus. Ca2+ transport was specific to midtubule segments, where 97% of the Ca2+ entering the tubule is sequestered within intracellular calcium stores and the remaining 3% is secreted into the lumen. Antagonists of voltage-gated (L-type) calcium channels decreased Ca2+ influx ≥fivefold in adenosine 3',5'-cyclic monophosphate (cAMP)-stimulated tubules, suggesting basolateral Ca2+ influx is facilitated by voltage-gated Ca2+ channels. Increasing fluid secretion through manipulation of intracellular levels of cAMP or Ca2+ had opposite effects on tubule Ca2+ transport. The adenylyl cyclase-cAMP-PKA pathway promotes Ca2+ sequestration whereas both 5-hydroxytryptamine and thapsigargin inhibited sequestration. Our results suggest that the midtubules of Acheta domesticus are dynamic calcium stores, which maintain hemolymph calcium concentration by manipulating rates of Ca2+ sequestration through stimulatory (cAMP) and inhibitory (Ca2+ ) regulatory pathways.
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Affiliation(s)
- Austin Browne
- Department of Biology, McMaster University, Hamilton, ON, Canada
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13
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Abstract
The Malpighian tubules of insects are structurally simple but functionally important organs, and their integrity is important for the normal excretory process. They are functional analogs of human kidneys which are important physiological organs as they maintain water and electrolyte balance in the blood and simultaneously help the body to get rid of waste and toxic products after various metabolic activities. In addition, it receives early indications of insults to the body such as immune challenge and other toxic components and is essential for sustaining life. According to National Vital Statistics Reports 2016, renal dysfunction has been ranked as the ninth most abundant cause of death in the USA. This chapter provides detailed descriptions of Drosophila Malpighian tubule development, physiology, immune function and also presents evidences that Malpighian tubules can be used as a model organ system to address the fundamental questions in developmental and functional disorders of the kidney.
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Affiliation(s)
- Naveen Kumar Gautam
- Embryotoxicology Laboratory, Environmental Toxicology Division, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow, 226001, Uttar Pradesh, India
| | - Puja Verma
- Department of Zoology, Cytogenetics Laboratory, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Madhu G Tapadia
- Department of Zoology, Cytogenetics Laboratory, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
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Abstract
Zinc is an essential micronutrient for all organisms. For multicellular organisms, zinc uptake, storage, distribution and export are tightly regulated at both cellular and organismal levels, to cope with the multiple requirements versus the toxicity of the metal ion. During the past decade, the fruit fly Drosophila melanogaster has become an important model organism for the elucidation of metazoan zinc homeostasis. This review describes our current knowledge of various zinc transporters in Drosophila, with an emphasis on the process of dietary zinc uptake in the fly. We also discuss how Drosophila was used as a model to facilitate our understanding of the role of zinc in neurodegenerative diseases.
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Affiliation(s)
- Guiran Xiao
- College of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, China; State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Zhou
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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15
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Browne A, O'Donnell MJ. Segment-specific Ca(2+) transport by isolated Malpighian tubules of Drosophila melanogaster: A comparison of larval and adult stages. J Insect Physiol 2016; 87:1-11. [PMID: 26802560 DOI: 10.1016/j.jinsphys.2016.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 01/08/2016] [Accepted: 01/19/2016] [Indexed: 06/05/2023]
Abstract
Haemolymph calcium homeostasis in insects is achieved through the regulation of calcium excretion by Malpighian tubules in two ways: (1) sequestration of calcium within biomineralized granules and (2) secretion of calcium in soluble form within the primary urine. Using the scanning ion-selective electrode technique (SIET), basolateral Ca(2+) transport was measured at the distal, transitional, main and proximal tubular segments of anterior tubules isolated from both 3rd instar larvae and adults of the fruit fly Drosophila melanogaster. Basolateral Ca(2+) transport exceeded transepithelial secretion by 800-fold and 11-fold in anterior tubules of larvae and adults, respectively. The magnitude of Ca(2+) fluxes across the distal tubule of larvae and adults were larger than fluxes across the downstream segments by 10 and 40 times, respectively, indicating a dominant role for the distal segment in whole animal Ca(2+) regulation. Basolateral Ca(2+) transport across distal tubules of Drosophila varied throughout the life cycle; Ca(2+) was released by distal tubules of larvae, taken up by distal tubules of young adults and was released once again by tubules of adults ⩾ 168 h post-eclosion. In adults and larvae, SIET measurements revealed sites of both Ca(2+) uptake and Ca(2+) release across the basolateral surface of the distal segment of the same tubule, indicating that Ca(2+) transport is bidirectional. Ca(2+) uptake across the distal segment of tubules of young adults and Ca(2+) release across the distal segment of tubules of older adults was also suggestive of reversible Ca(2+) storage. Our results suggest that the distal tubules of D. melanogaster are dynamic calcium stores which allow efficient haemolymph calcium regulation through active Ca(2+) sequestration during periods of high dietary calcium intake and passive Ca(2+) release during periods of calcium deficiency.
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Affiliation(s)
- Austin Browne
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
| | - Michael J O'Donnell
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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16
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Schellinger JN, Rodan AR. Use of the Ramsay Assay to Measure Fluid Secretion and Ion Flux Rates in the Drosophila melanogaster Malpighian Tubule. J Vis Exp 2015. [PMID: 26650886 DOI: 10.3791/53144] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Modulation of renal epithelial ion transport allows organisms to maintain ionic and osmotic homeostasis in the face of varying external conditions. The Drosophila melanogaster Malpighian (renal) tubule offers an unparalleled opportunity to study the molecular mechanisms of epithelial ion transport, due to the powerful genetics of this organism and the accessibility of its renal tubules to physiological study. Here, we describe the use of the Ramsay assay to measure fluid secretion rates from isolated fly renal tubules, with the use of ion-specific electrodes to measure sodium and potassium concentrations in the secreted fluid. This assay allows study of transepithelial fluid and ion fluxes of ~20 tubules at a time, without the need to transfer the secreted fluid to a separate apparatus to measure ion concentrations. Genetically distinct tubules can be analyzed to assess the role of specific genes in transport processes. Additionally, the bathing saline can be modified to examine the effects of its chemical characteristics, or drugs or hormones added. In summary, this technique allows the molecular characterization of basic mechanisms of epithelial ion transport in the Drosophila tubule, as well as regulation of these transport mechanisms.
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Affiliation(s)
| | - Aylin R Rodan
- Department of Internal Medicine, University of Texas Southwestern Medical Center;
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18
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Abstract
The Malpighian tubule is the main organ for excretion and osmoregulation in most insects. During a short period of embryonic development the tubules of Drosophila are shaped, undergo differentiation and become precisely positioned in the body cavity, so they become fully functional at the time of larval hatching a few hours later. In this review I explore three developmental events on the path to physiological maturation. First, I examine the molecular and cellular mechanisms that generate organ shape, focusing on the process of cell intercalation that drives tubule elongation, the roles of the cytoskeleton, the extracellular matrix and how intercalation is coordinated at the tissue level. Second, I look at the genetic networks that control the physiological differentiation of tubule cells and consider how distinctive physiological domains in the tubule are patterned. Finally, I explore how the organ is positioned within the body cavity and consider the relationship between organ position and function.
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Affiliation(s)
- Barry Denholm
- Department of Zoology, University of Cambridge, Cambridge, UK.
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19
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Hirata T, Cabrero P, Berkholz DS, Bondeson DP, Ritman EL, Thompson JR, Dow JAT, Romero MF. In vivo Drosophilia genetic model for calcium oxalate nephrolithiasis. Am J Physiol Renal Physiol 2012; 303:F1555-62. [PMID: 22993075 DOI: 10.1152/ajprenal.00074.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nephrolithiasis is a major public health problem with a complex and varied etiology. Most stones are composed of calcium oxalate (CaOx), with dietary excess a risk factor. Because of complexity of mammalian system, the details of stone formation remain to be understood. Here we have developed a nephrolithiasis model using the genetic model Drosophila melanogaster, which has a simple, transparent kidney tubule. Drosophilia reliably develops CaOx stones upon dietary oxalate supplementation, and the nucleation and growth of microliths can be viewed in real time. The Slc26 anion transporter dPrestin (Slc26a5/6) is strongly expressed in Drosophilia kidney, and biophysical analysis shows that it is a potent oxalate transporter. When dPrestin is knocked down by RNAi in fly kidney, formation of microliths is reduced, identifying dPrestin as a key player in oxalate excretion. CaOx stone formation is an ancient conserved process across >400 My of divergent evolution (fly and human), and from this study we can conclude that the fly is a good genetic model of nephrolithiasis.
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Affiliation(s)
- Taku Hirata
- Dept. Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Chintapalli VR, Terhzaz S, Wang J, Al Bratty M, Watson DG, Herzyk P, Davies SA, Dow JAT. Functional correlates of positional and gender-specific renal asymmetry in Drosophila. PLoS One 2012; 7:e32577. [PMID: 22496733 PMCID: PMC3319558 DOI: 10.1371/journal.pone.0032577] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 01/27/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In humans and other animals, the internal organs are positioned asymmetrically in the body cavity, and disruption of this body plan can be fatal in humans. The mechanisms by which internal asymmetry are established are presently the subject of intense study; however, the functional significance of internal asymmetry (outside the brain) is largely unexplored. Is internal asymmetry functionally significant, or merely an expedient way of packing organs into a cavity? METHODOLOGY/PRINCIPAL FINDINGS Like humans, Drosophila shows internal asymmetry, with the gut thrown into stereotyped folds. There is also renal asymmetry, with the rightmost pair of renal (Malpighian) tubules always ramifying anteriorly, and the leftmost pair always sitting posteriorly in the body cavity. Accordingly, transcriptomes of anterior-directed (right-side) and posterior-directed (left-side) Malpighian (renal) tubules were compared in both adult male and female Drosophila. Although genes encoding the basic functions of the tubules (transport, signalling) were uniformly expressed, some functions (like innate immunity) showed positional or gender differences in emphasis; others, like calcium handling or the generation of potentially toxic ammonia, were reserved for just the right-side or left-side tubules, respectively. These findings correlated with the distinct locations of each tubule pair within the body cavity. Well known developmental genes (like dorsocross, dachshund and doublesex) showed continuing, patterned expression in adult tubules, implying that somatic tissues maintain both left-right and gender identities throughout life. Gender asymmetry was also noted, both in defence and in male-specific expression of receptors for neuropeptide F and sex-peptide: NPF elevated calcium only in male tubules. CONCLUSIONS/SIGNIFICANCE Accordingly, the physical asymmetry of the tubules in the body cavity is directly adaptive. Now that the detailed machinery underlying internal asymmetry is starting to be delineated, our work invites the investigation, not just of tissues in isolation, but in the context of their unique physical locations and milieux.
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Affiliation(s)
- Venkateswara R. Chintapalli
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Selim Terhzaz
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jing Wang
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mohammed Al Bratty
- Strathclyde Institute for Pharmacy and Biomedical Sciences, Glasgow, United Kingdom
| | - David G. Watson
- Strathclyde Institute for Pharmacy and Biomedical Sciences, Glasgow, United Kingdom
| | - Pawel Herzyk
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Shireen A. Davies
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Julian A. T. Dow
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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21
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Chen YH, Liu HP, Chen HY, Tsai FJ, Chang CH, Lee YJ, Lin WY, Chen WC. Ethylene glycol induces calcium oxalate crystal deposition in Malpighian tubules: a Drosophila model for nephrolithiasis/urolithiasis. Kidney Int 2011; 80:369-77. [PMID: 21451462 DOI: 10.1038/ki.2011.80] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Several animal species are used to study calcium oxalate urolithiasis; however, an ideal model has yet to be identified. We used Drosophila as a model organism and fed the flies lithogenic agents such as ethylene glycol, hydroxyl-L-proline, and sodium oxalate. At different times, the Malpighian tubules, the kidney equivalent of insects, were dissected and a polarized light microscope used to highlight the birefringent crystals. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed that the crystal composition was predominately calcium oxalate. Furthermore, administration of potassium citrate successfully reduced the quantity of and modulated the integrity of the ethylene glycol-induced crystals. Thus, the Drosophila model of bio-mineralization produces crystals in the urinary system through many lithogenic agents, permits observation of crystal formation, and is amenable to genetic manipulation. This model may mimic the etiology and clinical manifestations of calcium oxalate stone formation and aid in identification of the genetic basis of this disease.
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22
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Chahine S, O'Donnell MJ. Physiological and molecular characterization of methotrexate transport by Malpighian tubules of adult Drosophila melanogaster. J Insect Physiol 2009; 55:927-935. [PMID: 19545574 DOI: 10.1016/j.jinsphys.2009.06.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/04/2009] [Accepted: 06/11/2009] [Indexed: 05/28/2023]
Abstract
A radioisotope tracer technique and quantitative PCR were used to study the mechanisms and regulation of transepithelial transport of the type II organic anion methotrexate (MTX) by the Malpighian tubules of Drosophila melanogaster. Transport of MTX was saturable and Na(+)-independent; the kinetic parameters J(max) and K(t) were 437fmolmin(-1) and 23.5microM, respectively. The transport of MTX was competitively inhibited by phenol red and probenecid; non-competitively inhibited by salicylate, verapamil and MK-571; and uncompetitively inhibited by Texas Red. Dietary exposure to 0.1mM MTX led to dramatic increases in gene expression for several members of the ABC family of transporters in both the Malpighian tubules and the gut. Our results suggest that multiple transporters are upregulated in response to dietary exposure to MTX. Increased levels of the protein products which may result from expression of these genes may enhance elimination of toxic compounds such as MTX or its metabolites.
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Affiliation(s)
- Sarah Chahine
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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23
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Abstract
SUMMARY
Calcium signalling and calcium homeostasis are essential for life. Studies of calcium signalling thus constitute a major proportion of research in the life sciences, although the majority of these studies are based in cell lines or isolated cells. Epithelial cells and tissues are essential in the regulation of critical physiological processes, including fluid transport; and so the modulation of such processes in vivo by cell-specific calcium signalling is thus of interest. In this review, we describe the approaches to measuring intracellular calcium in the genetically tractable fluid-transporting tissue, the Drosophila Malpighian tubule by targeting cell-specific protein-based calcium reporters to defined regions,cells and intracellular compartments of the intact Malpighian tubule. We also discuss recent findings on the roles of plasma membrane and intracellular calcium channels; and on organellar stores – including mitochondria,Golgi and peroxisomes – in Malpighian tubule function.
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Affiliation(s)
- Shireen A. Davies
- Integrative and Systems Biology Group, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
| | - Selim Terhzaz
- Integrative and Systems Biology Group, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
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24
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Southall TD, Terhzaz S, Cabrero P, Chintapalli VR, Evans JM, Dow JAT, Davies SA. Novel subcellular locations and functions for secretory pathway Ca2+/Mn2+-ATPases. Physiol Genomics 2006; 26:35-45. [PMID: 16609144 DOI: 10.1152/physiolgenomics.00038.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Secretory pathway Ca2+/Mn2+-ATPases (SPCAs) are important for maintenance of cellular Ca2+and Mn2+homeostasis, and, to date, all SPCAs have been found to localize to the Golgi apparatus. The single Drosophila SPCA gene ( SPoCk) was identified by an in silico screen for novel Ca2+-ATPases. It encoded three SPoCk isoforms with novel, distinct subcellular specificities in the endoplasmic reticulum (ER) and peroxisomes in addition to the Golgi. Furthermore, expression of the peroxisome-associated SPoCk isoform was sexually dimorphic. Overexpression of organelle-specific SPoCk isoforms impacted on cytosolic Ca2+handling in both cultured Drosophila cells and a transporting epithelium, the Drosophila Malpighian (renal) tubule. Specifically, the ER isoform impacted on inositol ( 1 , 4 , 5 )-trisphosphate-mediated Ca2+signaling and the Golgi isoform impacted on diuresis, whereas the peroxisome isoform colocalized with Ca2+“spherites” and impacted on calcium storage and transport. Interfering RNA directed against the common exons of the three SPoCk isoforms resulted in aberrant Ca2+signaling and abolished neuropeptide-stimulated diuresis by the tubule. SPoCk thus contributed to both of the contrasting requirements for Ca2+in transporting epithelia: to transport or store Ca2+in bulk without compromising its use as a signal.
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Affiliation(s)
- Tony D Southall
- Division of Molecular Genetics, Anderson College Complex, University of Glasgow, Glasgow, United Kingdom
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25
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Evans JM, Allan AK, Davies SA, Dow JAT. Sulphonylurea sensitivity and enriched expression implicate inward rectifier K+ channels in Drosophila melanogaster renal function. ACTA ACUST UNITED AC 2006; 208:3771-83. [PMID: 16169954 DOI: 10.1242/jeb.01829] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Insect Malpighian (renal) tubules are capable of transporting fluid at remarkable rates. Secondary active transport of potassium at the apical surface of the principal cell must be matched by a high-capacity basolateral potassium entry route. A recent microarray analysis of Drosophila tubule identified three extremely abundant and enriched K(+) channel genes encoding the three inward rectifier channels of Drosophila: ir, irk2 and irk3. Enriched expression of inward rectifier channels in tubule was verified by quantitative RT-PCR, and all three IRKs localised to principal cells of the main segment (and ir and irk3 to the lower tubule) by in situ hybridisation, suggesting roles both in primary secretion and reabsorption. A new splice form of irk2 was also identified. The role of inward rectifiers in fluid secretion was assessed with a panel of selective inhibitors of inward rectifier channels, the antidiabetic sulphonylureas. All completely inhibited fluid secretion, with IC(50)s of 0.78 mmol l(-1) for glibenclamide and approximately 5 mmol l(-1) for tolbutamide, 0.01 mmol l(-1) for minoxidil and 0.1 mmol l(-1) for diazoxide. This pharmacology is consistent with a lower-affinity class of inward rectifier channel that does not form an obligate multimer with the sulphonylurea receptor (SUR), although effects on non-IRK targets cannot be excluded. Glibenclamide inhibited fluid secretion similarly to basolateral K(+)-free saline. Radiolabelled glibenclamide is both potently transported and metabolised by tubule. Furthermore, glibenclamide is capable of blocking transport of the organic dye amaranth (azorubin S), at concentrations of glibenclamide much lower than required to impact on fluid secretion. Glibenclamide thus interacts with tubule in three separate ways; as a potent inhibitor of fluid secretion, as an inhibitor (possibly competitive) of an organic solute transporter and as a substrate for excretion and metabolism.
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Affiliation(s)
- Jennifer M Evans
- Division of Molecular Genetics, Faculty of Biomedical and Life Sciences, University of Glasgow, UK
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26
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MacPherson MR, Pollock VP, Kean L, Southall TD, Giannakou ME, Broderick KE, Dow JAT, Hardie RC, Davies SA. Transient receptor potential-like channels are essential for calcium signaling and fluid transport in a Drosophila epithelium. Genetics 2005; 169:1541-52. [PMID: 15695363 PMCID: PMC1449567 DOI: 10.1534/genetics.104.035139] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Accepted: 12/09/2004] [Indexed: 11/18/2022] Open
Abstract
Calcium signaling is an important mediator of neuropeptide-stimulated fluid transport by Drosophila Malpighian (renal) tubules. We demonstrate the first epithelial role, in vivo, for members of the TRP family of calcium channels. RT-PCR revealed expression of trp, trpl, and trpgamma in tubules. Use of antipeptide polyclonal antibodies for TRP, TRPL, and TRPgamma showed expression of all three channels in type 1 (principal) cells in the tubule main segment. Neuropeptide (CAP(2b))-stimulated fluid transport rates were significantly reduced in tubules from the trpl(302) mutant and the trpl;trp double mutant, trpl(302);trp(343). However, a trp null, trp(343), had no impact on stimulated fluid transport. Measurement of cytosolic calcium concentrations ([Ca(2+)](i)) in tubule principal cells using an aequorin transgene in trp and trpl mutants showed a reduction in calcium responses in trpl(302). Western blotting of tubule preparations from trp and trpl mutants revealed a correlation between TRPL levels and CAP(2b)-stimulated fluid transport and calcium signaling. Rescue of trpl(302) with a trpl transgene under heat-shock control resulted in a stimulated fluid transport phenotype that was indistinguishable from wild-type tubules. Furthermore, restoration of normal stimulated rates of fluid transport by rescue of trpl(302) was not compromised by introduction of the trp null, trp(343). Thus, in an epithelial context, TRPL is sufficient for wild-type responses. Finally, a scaffolding component of the TRPL/TRP-signaling complex, INAD, is not expressed in tubules, suggesting that inaD is not essential for TRPL/TRP function in Drosophila tubules.
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O'Donnell MJ, Rheault MR. Ion-selective microelectrode analysis of salicylate transport by the Malpighian tubules and gut ofDrosophila melanogaster. J Exp Biol 2005; 208:93-104. [PMID: 15601881 DOI: 10.1242/jeb.01374] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYTransport of the organic anion salicylate by the Malpighian tubules and gut of larval and adult fruit flies was studied using two salicylate-selective microelectrode methods. The first method combined the high selectivity of tridodecylmethylammonium-based electrodes for salicylate with the self-referencing ion-selective microelectrode technique for non-invasive spatial and temporal analysis of salicylate flux. Measurements with this technique revealed secretion of salicylate across the main and distal segments of the Malpighian tubule as well as the midgut, ileum and rectum. The second method used a salicylate-selective microelectrode to measure the concentration of salicylate in fluid droplets secreted by isolated DrosophilaMalpighian tubules set up in a Ramsay secretion assay. Transepithelial salicylate flux was calculated as the product of fluid secretion rate and secreted fluid salicylate concentration. Measurements with this method revealed that salicylate transport was active and saturable; the kinetic parameters Jmax and Kt were 2.72 pmol min-1 tubule-1 and 0.046 mmol l-1,respectively. Measurements of transepithelial salicylate flux determined by both microelectrode methods were in good agreement. Transepithelial flux measurements measured by microelectrodes were also validated by comparing them with measurements of radiolabelled salicylate levels in secreted droplets. Salicylate concentrations in haemolymph samples were measured with salicylate-selective microelectrodes after injection of salicylate into the haemocoel or after insects were fed salicylate-rich diets. The rate of salicylate secretion by Malpighian tubules in vitro was sufficient to account for the measured rate of decline of salicylate concentration in the haemolymph in vivo.
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Affiliation(s)
- Michael J O'Donnell
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
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28
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Wang J, Kean L, Yang J, Allan AK, Davies SA, Herzyk P, Dow JAT. Function-informed transcriptome analysis of Drosophila renal tubule. Genome Biol 2004; 5:R69. [PMID: 15345053 PMCID: PMC522876 DOI: 10.1186/gb-2004-5-9-r69] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Revised: 06/25/2004] [Accepted: 07/23/2004] [Indexed: 11/25/2022] Open
Abstract
Analysis of the transcriptome of the Drosophila melanogaster Malpighian (renal) tubule gives a radically new view of the function of the tubule, emphasising solute transport rather than fluid secretion. Background Comprehensive, tissue-specific, microarray analysis is a potent tool for the identification of tightly defined expression patterns that might be missed in whole-organism scans. We applied such an analysis to Drosophila melanogaster Malpighian (renal) tubule, a defined differentiated tissue. Results The transcriptome of the D. melanogaster Malpighian tubule is highly reproducible and significantly different from that obtained from whole-organism arrays. More than 200 genes are more than 10-fold enriched and over 1,000 are significantly enriched. Of the top 200 genes, only 18 have previously been named, and only 45% have even estimates of function. In addition, 30 transcription factors, not previously implicated in tubule development, are shown to be enriched in adult tubule, and their expression patterns respect precisely the domains and cell types previously identified by enhancer trapping. Of Drosophila genes with close human disease homologs, 50 are enriched threefold or more, and eight enriched 10-fold or more, in tubule. Intriguingly, several of these diseases have human renal phenotypes, implying close conservation of renal function across 400 million years of divergent evolution. Conclusions From those genes that are identifiable, a radically new view of the function of the tubule, emphasizing solute transport rather than fluid secretion, can be obtained. The results illustrate the phenotype gap: historically, the effort expended on a model organism has tended to concentrate on a relatively small set of processes, rather than on the spread of genes in the genome.
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Affiliation(s)
- Jing Wang
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
| | - Laura Kean
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
| | - Jingli Yang
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
| | - Adrian K Allan
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
| | - Shireen A Davies
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
| | - Pawel Herzyk
- Sir Henry Wellcome Functional Genomics Facility, University of Glasgow, Glasgow G12 8QQ, UK
| | - Julian AT Dow
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK
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29
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Rheault MR, O'Donnell MJ. Organic cation transport by Malpighian tubules ofDrosophila melanogaster: application of two novel electrophysiological methods. J Exp Biol 2004; 207:2173-84. [PMID: 15143149 DOI: 10.1242/jeb.01003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYTransport of the prototypical organic cation tetraethylammonium (TEA) by the Malpighian tubules, ureters and gut of Drosophila melanogasterwas studied using two novel electrophysiological techniques. Both techniques exploited the high selectivity of the cation exchanger potassium tetra-p-chlorophenylborate for tetraalkylammonium compounds relative to inorganic cations such as K+. In the first technique, TEA fluxes were measured using a non-invasive self-referencing TEA-selective microelectrode positioned in the unstirred layer near the surface of each tissue. TEA fluxes from bath to lumen as large as 6 pmol cm–2s–1 were measured across the lower (reabsorptive) segment of the Malpighian tubule and the ureter bathed in saline containing 0.1 mmol l–1 TEA. Corresponding bath-to-lumen fluxes across the secretory main segment of the Malpighian tubule and the posterior midgut were∼1 pmol cm–2 s–1. TEA transport by the lower Malpighian tubule was enhanced by hyperpolarization of the basolateral membrane potential and was inhibited by cimetidine, quinidine, vinblastine and verapamil. In the second technique, TEA concentration was measured using a TEA-selective microelectrode positioned in droplets of fluid secreted by Malpighian tubules set up in saline droplets under oil in a Ramsay assay. Results from the Ramsay assay confirmed the dominant role of the lower Malpighian tubule in net transepithelial secretion of TEA and inhibition of TEA transport by cimetidine. Kinetic parameters (Jmax and Kt) were determined using both approaches.
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Affiliation(s)
- Mark R Rheault
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Canada L8S 4K1.
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Abstract
Classically, biologists try to understand their complex systems by simplifying them to a level where the problem is tractable, typically moving from whole animal and organ-level biology to the immensely powerful "cellular" and "molecular" approaches. However, the limitations of this reductionist approach are becoming apparent, leading to calls for a new, "integrative" physiology. Rather than use the term as a rallying cry for classical organismal physiology, we have defined it as the study of how gene products integrate into the function of whole tissues and intact organisms. From this viewpoint, the convergence between integrative physiology and functional genomics becomes clear; both seek to understand gene function in an organismal context, and both draw heavily on transgenics and genetics in genetic models to achieve their goal. This convergence between historically divergent fields provides powerful leverage to those physiologists who can phrase their research questions in a particular way. In particular, the use of appropriate genetic model organisms provides a wealth of technologies (of which microarrays and knock-outs are but two) that allow a new precision in physiological analysis. We illustrate this approach with an epithelial model system, the Malpighian (renal) tubule of Drosophila melanogaster. With the use of the beautiful genetic tools and extensive genomic resources characteristic of this genetic model, it has been possible to gain unique insights into the structure, function, and control of epithelia.
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Affiliation(s)
- Julian T Dow
- Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK.
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Rheault MR, O'Donnell MJ. Analysis of epithelial K+ transport in Malpighian tubules ofDrosophila melanogaster: evidence for spatial and temporal heterogeneity. J Exp Biol 2001; 204:2289-99. [PMID: 11507112 DOI: 10.1242/jeb.204.13.2289] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYTransport of K+ by the lower, main and distal segments of the Malpighian tubules of Drosophila melanogaster was analyzed using self-referencing K+-selective microelectrodes. Transport properties of the Malpighian tubules of Drosophila melanogaster change along their length. Self-referencing ion-selective (SeRIS) microelectrode measurements (relative to the bath concentration of 20 mmoll−1) showed a 1% reduction (P<0.05) of [K+] in the unstirred layer adjacent to the main segment of the Malpighian tubules, confirming secretion of K+ from the bath to the tubule lumen. Conversely, SeRIS measurements showed a 0.7% increase (P<0.05) in [K+] in the unstirred layer adjacent to the lower segment of Malpighian tubules, confirming reabsorption of K+ from the luminal fluid to the bath. Measurements using SeRIS also showed that the distal segment neither secreted nor reabsorbed K+. There was pronounced spatial heterogeneity in K+ transport by the lower segment and the main segment; not all morphologically similar cells participated equally in K+ transport, nor did all main segment cells respond equally to stimulation of K+ transport by cyclic AMP. Pronounced temporal heterogeneity in K+ reabsorption by the lower Malpighian tubules was also observed. We suggest that this reflects periodic reduction in K+ reabsorption due to retention of fluid within the lower segment when the ureter contracts.
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Affiliation(s)
- M R Rheault
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
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MacPherson MR, Pollock VP, Broderick KE, Kean L, O'Connell FC, Dow JA, Davies SA. Model organisms: new insights into ion channel and transporter function. L-type calcium channels regulate epithelial fluid transport in Drosophila melanogaster. Am J Physiol Cell Physiol 2001; 280:C394-407. [PMID: 11208535 DOI: 10.1152/ajpcell.2001.280.2.c394] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neuropeptide CAP2b stimulates fluid transport obligatorily via calcium entry, nitric oxide, and cGMP in Drosophila melanogaster Malpighian (renal) tubules. We have shown by RT-PCR that the Drosophila L-type calcium channel alpha1-subunit genes Dmca1D and Dmca1A (nbA) are both expressed in tubules. CAP2b-stimulated fluid transport and cytosolic calcium concentration ([Ca2+]i) increases are inhibited by the L-type calcium channel blockers verapamil and nifedipine. cGMP-stimulated fluid transport is verapamil and nifedipine sensitive. Furthermore, cGMP induces a slow [Ca2+]i increase in tubule principal cells via verapamil- and nifedipine-sensitive calcium entry; RT-PCR shows that tubules express Drosophila cyclic nucleotide-gated channel (cng). Additionally, thapsigargin-induced [Ca2+]i increase is verapamil sensitive. Phenylalkylamines bind with differing affinities to the basolateral and apical surfaces of principal cells in the main segment; however, dihydropyridine binds apically in the tubule initial segment. Immunocytochemical evidence suggests localization of alpha1-subunits to both basolateral and apical surfaces of principal cells in the tubule main segment. We suggest roles for L-type calcium channels and cGMP-mediated calcium influx in both calcium signaling and fluid transport mechanisms in Drosophila.
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Affiliation(s)
- M R MacPherson
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, United Kingdom
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