RESUMEN
The Hippo signaling pathway functions through Yorkie to control tissue growth and homeostasis. How this pathway regulates non-developmental processes remains largely unexplored. Here, we report an essential role for Hippo signaling in innate immunity whereby Yorkie directly regulates the transcription of the Drosophila IκB homolog, Cactus, in Toll receptor-mediated antimicrobial response. Loss of Hippo pathway tumor suppressors or activation of Yorkie in fat bodies, the Drosophila immune organ, leads to elevated cactus mRNA levels, decreased expression of antimicrobial peptides, and vulnerability to infection by Gram-positive bacteria. Furthermore, Gram-positive bacteria acutely activate Hippo-Yorkie signaling in fat bodies via the Toll-Myd88-Pelle cascade through Pelle-mediated phosphorylation and degradation of the Cka subunit of the Hippo-inhibitory STRIPAK PP2A complex. Our studies elucidate a Toll-mediated Hippo signaling pathway in antimicrobial response, highlight the importance of regulating IκB/Cactus transcription in innate immunity, and identify Gram-positive bacteria as extracellular stimuli of Hippo signaling under physiological settings.
Asunto(s)
Drosophila melanogaster/inmunología , Inmunidad Innata , Transducción de Señal , Animales , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Drosophila melanogaster/microbiología , Escherichia coli/fisiología , Cuerpo Adiposo/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Larva/metabolismo , Masculino , Pectobacterium carotovorum/fisiología , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Staphylococcus aureus/fisiología , Receptores Toll-Like/metabolismoRESUMEN
Aging of immune organs, termed as immunosenescence, is suspected to promote systemic inflammation and age-associated disease. The cause of immunosenescence and how it promotes disease, however, has remained unclear. We report that the Drosophila fat body, a major immune organ, undergoes immunosenescence and mounts strong systemic inflammation that leads to deregulation of immune deficiency (IMD) signaling in the midgut of old animals. Inflamed old fat bodies secrete circulating peptidoglycan recognition proteins that repress IMD activity in the midgut, thereby promoting gut hyperplasia. Further, fat body immunosenecence is caused by age-associated lamin-B reduction specifically in fat body cells, which then contributes to heterochromatin loss and derepression of genes involved in immune responses. As lamin-associated heterochromatin domains are enriched for genes involved in immune response in both Drosophila and mammalian cells, our findings may provide insights into the cause and consequence of immunosenescence during mammalian aging. PAPERFLICK:
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Cuerpo Adiposo/inmunología , Lamina Tipo B/metabolismo , Envejecimiento , Animales , Proliferación Celular , Drosophila melanogaster/química , Drosophila melanogaster/inmunología , Cuerpo Adiposo/crecimiento & desarrollo , Cuerpo Adiposo/metabolismo , Tracto Gastrointestinal/crecimiento & desarrollo , Tracto Gastrointestinal/inmunología , Tracto Gastrointestinal/metabolismo , Heterocromatina , Inflamación/inmunología , Mamíferos/inmunología , Modelos Animales , Transducción de SeñalRESUMEN
Infections disturb metabolic homeostasis in many contexts, but the underlying connections are not completely understood. To address this, we use paired genetic and computational screens in Drosophila to identify transcriptional regulators of immunity and pathology and their associated target genes and physiologies. We show that Mef2 is required in the fat body for anabolic function and the immune response. Using genetic and biochemical approaches, we find that MEF2 is phosphorylated at a conserved site in healthy flies and promotes expression of lipogenic and glycogenic enzymes. Upon infection, this phosphorylation is lost, and the activity of MEF2 changes--MEF2 now associates with the TATA binding protein to bind a distinct TATA box sequence and promote antimicrobial peptide expression. The loss of phosphorylated MEF2 contributes to loss of anabolic enzyme expression in Gram-negative bacterial infection. MEF2 is thus a critical transcriptional switch in the adult fat body between metabolism and immunity.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/inmunología , Drosophila melanogaster/metabolismo , Factores Reguladores Miogénicos/metabolismo , Secuencia de Aminoácidos , Animales , Candida albicans , Proteínas de Drosophila/inmunología , Drosophila melanogaster/microbiología , Enterobacter cloacae , Cuerpo Adiposo/metabolismo , Regulación de la Expresión Génica , Glucógeno/metabolismo , Metabolismo , Mycobacterium marinum , Factores Reguladores Miogénicos/inmunología , Fosforilación , Proteína de Unión a TATA-Box/metabolismoRESUMEN
Lipid distribution in an organism is mediated by the interplay between lipoprotein particles, lipoprotein receptors and class B scavenger receptors of the CD36 family. CD36 is a multifunctional protein mediating lipid uptake, mobilization and signaling at the plasma membrane and inside of the cell. The CD36 protein family has 14 members in Drosophila melanogaster, which allows for the differentiated analysis of their functions. Here, we unravel a role for the so far uncharacterized scavenger receptor Bez in lipid export from Drosophila adipocytes. Bez shares the lipid binding residue with CD36 and is expressed at the plasma membrane of the embryonic, larval and adult fat body. Bez loss of function lowers the organismal availability of storage lipids and blocks the maturation of egg chambers in ovaries. We demonstrate that Bez interacts with the APOB homolog Lipophorin at the plasma membrane of adipocytes and trace the Bez-dependent transfer of an alkyne-labeled fatty acid from adipocytes to Lipophorin. Our study demonstrates how lipids are distributed by scavenger receptor-lipoprotein interplay and contribute to the metabolic control of development.
Asunto(s)
Antígenos CD36 , Proteínas de Drosophila , Drosophila melanogaster , Cuerpo Adiposo , Metabolismo de los Lípidos , Animales , Femenino , Adipocitos/metabolismo , Antígenos CD36/metabolismo , Antígenos CD36/genética , Membrana Celular/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Cuerpo Adiposo/metabolismo , Lipoproteínas/metabolismo , Ovario/metabolismo , Receptores Depuradores/metabolismo , Receptores Depuradores/genéticaRESUMEN
In Drosophila, the fat body (FB), a functional analog of the vertebrate adipose tissue, is the nutrient sensor that conveys the nutrient status to the insulin-producing cells (IPCs) in the fly brain to release Drosophila insulin-like peptides (Dilps). Dilp secretion in turn regulates energy balance and promotes systemic growth. We identify Unpaired 2 (Upd2), a protein with similarities to type I cytokines, as a secreted factor produced by the FB in the fed state. When upd2 function is perturbed specifically in the FB, it results in a systemic reduction in growth and alters energy metabolism. Upd2 activates JAK/STAT signaling in a population of GABAergic neurons that project onto the IPCs. This activation relieves the inhibitory tone of the GABAergic neurons on the IPCs, resulting in the secretion of Dilps. Strikingly, we find that human Leptin can rescue the upd2 mutant phenotypes, suggesting that Upd2 is the functional homolog of Leptin.
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Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Metabolismo Energético , Insulina/metabolismo , Neuropéptidos/metabolismo , Animales , Metabolismo de los Hidratos de Carbono , Cuerpo Adiposo/metabolismo , Grasas/metabolismo , Femenino , Humanos , Secreción de Insulina , Quinasas Janus/metabolismo , Leptina/metabolismo , MasculinoRESUMEN
Knowledge of adipogenetic mechanisms is essential to understand and treat conditions affecting organismal metabolism and adipose tissue health. In Drosophila, mature adipose tissue (fat body) exists in larvae and adults. In contrast to the well-known development of the larval fat body from the embryonic mesoderm, adult adipogenesis has remained mysterious. Furthermore, conclusive proof of its physiological significance is lacking. Here, we show that the adult fat body originates from a pool of undifferentiated mesodermal precursors that migrate from the thorax into the abdomen during metamorphosis. Through in vivo imaging, we found that these precursors spread from the ventral midline and cover the inner surface of the abdomen in a process strikingly reminiscent of embryonic mesoderm migration, requiring fibroblast growth factor (FGF) signaling as well. FGF signaling guides migration dorsally and regulates adhesion to the substrate. After spreading is complete, precursor differentiation involves fat accumulation and cell fusion that produces mature binucleate and tetranucleate adipocytes. Finally, we show that flies where adult adipogenesis is impaired by knock down of FGF receptor Heartless or transcription factor Serpent display ectopic fat accumulation in oenocytes and decreased resistance to starvation. Our results reveal that adult adipogenesis occurs de novo during metamorphosis and demonstrate its crucial physiological role.
Asunto(s)
Adipogénesis , Drosophila , Animales , Drosophila/metabolismo , Cuerpo Adiposo/metabolismo , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Tejido Adiposo/metabolismoRESUMEN
In Lepidoptera and Diptera, the fat body dissociates into single cells in nondiapause pupae, but it does not dissociate in diapause pupae until diapause termination. Using the cotton bollworm, Helicoverpa armigera, as a model of pupal diapause insects, we illustrated the catalytic mechanism and physiological importance of fat body cell dissociation in regulating pupal development and diapause. In nondiapause pupae, cathepsin L (CatL) activates matrix metalloproteinases (Mmps) that degrade extracellular matrix proteins and cause fat body cell dissociation. Mmp-induced fat body cell dissociation activates lipid metabolism through transcriptional regulation, and the resulting energetic supplies increase brain metabolic activity (i.e., mitochondria respiration and insulin signaling) and thus promote pupal development. In diapause pupae, low activities of CatL and Mmps prevent fat body cell dissociation and lipid metabolism from occurring, maintaining pupal diapause. Importantly, as demonstrated by chemical inhibitor treatments and CRISPR-mediated gene knockouts, Mmp inhibition delayed pupal development and moderately increased the incidence of pupal diapause, while Mmp stimulation promoted pupal development and moderately averted pupal diapause. This study advances our recent understanding of fat body biology and insect diapause regulation.
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Diapausa de Insecto , Mariposas Nocturnas , Animales , Pupa/metabolismo , Cuerpo Adiposo/metabolismo , Metabolismo de los Lípidos , Mariposas Nocturnas/genética , Metaloproteinasas de la Matriz/metabolismoRESUMEN
The interphase nuclear envelope (NE) is extensively remodeled during nuclear pore complex (NPC) insertion. How this remodeling occurs and why it requires Torsin ATPases, which also regulate lipid metabolism, remains poorly understood. Here, we show that Drosophila Torsin (dTorsin) affects lipid metabolism via the NEP1R1-CTDNEP1 phosphatase and the Lipin phosphatidic acid (PA) phosphatase. This includes that Torsins remove NEP1R1-CTDNEP1 from the NE in fly and mouse cells, leading to subsequent Lipin exclusion from the nucleus. NEP1R1-CTDNEP1 downregulation also restores nuclear pore membrane fusion in post-mitotic dTorsinKO fat body cells. However, dTorsin-associated nuclear pore defects do not correlate with lipidomic abnormalities and are not resolved by silencing of Lipin. Further testing confirmed that membrane fusion continues in cells with hyperactivated Lipin. It also led to the surprising finding that excessive PA metabolism inhibits recruitment of the inner ring complex Nup35 subunit, resulting in elongated channel-like structures in place of mature nuclear pores. We conclude that the NEP1R1-CTDNEP1 phosphatase affects interphase NPC biogenesis by lipid-dependent and lipid-independent mechanisms, explaining some of the pleiotropic effects of Torsins.
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Proteínas de Drosophila/metabolismo , Poro Nuclear/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Animales , Proteínas de Drosophila/genética , Drosophila melanogaster , Cuerpo Adiposo/citología , Cuerpo Adiposo/metabolismo , Metabolismo de los Lípidos , Fusión de Membrana , Fosfoproteínas Fosfatasas/genéticaRESUMEN
For in vivo functional analysis of a protein of interest (POI), multiple transgenic strains with a POI that harbors different tags are needed but generation of these strains is still labor-intensive work. To overcome this, we have developed a versatile Drosophila toolkit with a genetically encoded single-chain variable fragment for the HA epitope tag: 'HA Frankenbody'. This system allows various analyses of HA-tagged POI in live tissues by simply crossing an HA Frankenbody fly with an HA-tagged POI fly. Strikingly, the GFP-mCherry tandem fluorescent-tagged HA Frankenbody revealed a block in autophagic flux and an accumulation of enlarged autolysosomes in the last instar larval and prepupal fat body. Mechanistically, lysosomal activity was downregulated at this stage, and endocytosis, but not autophagy, was indispensable for the swelling of lysosomes. Furthermore, forced activation of lysosomes by fat body-targeted overexpression of Mitf, the single MiTF/TFE family gene in Drosophila, suppressed the lysosomal swelling and resulted in pupal lethality. Collectively, we propose that downregulated lysosomal function in the fat body plays a role in the metamorphosis of Drosophila.
Asunto(s)
Proteínas de Drosophila , Drosophila , Animales , Autofagia/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Cuerpo Adiposo/metabolismo , Larva/metabolismo , Lisosomas/metabolismoRESUMEN
In this study, we found that in the adipose tissue of wildtype animals, insulin and TGF-ß signalling converge via a BMP antagonist short gastrulation (sog) to regulate ECM remodelling. In tumour bearing animals, Sog also modulates TGF-ß signalling to regulate ECM accumulation in the fat body. TGF-ß signalling causes ECM retention in the fat body and subsequently depletes muscles of fat body-derived ECM proteins. Activation of insulin signalling, inhibition of TGF-ß signalling, or modulation of ECM levels via SPARC, Rab10 or Collagen IV in the fat body, is able to rescue tissue wasting in the presence of tumour. Together, our study highlights the importance of adipose ECM remodelling in the context of cancer cachexia.
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Caquexia , Neoplasias , Animales , Caquexia/etiología , Caquexia/metabolismo , Drosophila , Insulina , Cuerpo Adiposo/metabolismo , Tejido Adiposo/metabolismo , Factor de Crecimiento Transformador beta , Neoplasias/complicacionesRESUMEN
The fat body plays a central role in the regulation of the life cycle of insects and acts as the major site for detoxification, nutrient storage, energy metabolism, and innate immunity. However, the diversity of cell types in the fat body, as well as how these cell subsets respond to virus infection, remains largely unknown. We used single-nucleus RNA sequencing to identify 23 distinct clusters representing adipocyte, hemocyte, epithelial cell, muscle cell, and glial cell types in the fat body of silkworm larvae. Further, by analysis of viral transcriptomes in each cell subset, we reveal that all fat body cells could be infected by Bombyx mori nucleopolyhedrovirus (BmNPV) at 72 h postinfection, and that the majority of infected cells carried at least a medium viral load, whereas most cells infected by BmNPV at 24 h postinfection had only low levels of infection. Finally, we characterize the responses occurring in the fat body cell clusters on BmNPV infection, which, on one hand, mainly reduce their metabolic functions, involving energy, carbohydrates, lipids, and amino acids, but, on the other hand, initiate a strong antiviral response. Our single-nucleus RNA sequencing analysis reveals the diversity of insect fat body cells and provides a resource of gene expression profiles for a systems-level understanding of their response to virus infection.
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Bombyx , Cuerpo Adiposo , Animales , Cuerpo Adiposo/metabolismo , Bombyx/genética , Bombyx/metabolismo , Larva , InmunidadRESUMEN
The systemic regulation of stem cells ensures that they meet the needs of the organism during growth and in response to injury. A key point of regulation is the decision between quiescence and proliferation. During development, Drosophila neural stem cells (neuroblasts) transit through a period of quiescence separating distinct embryonic and postembryonic phases of proliferation. It is known that neuroblasts exit quiescence via a hitherto unknown pathway in response to a nutrition-dependent signal from the fat body. We have identified a population of glial cells that produce insulin/IGF-like peptides in response to nutrition, and we show that the insulin/IGF receptor pathway is necessary for neuroblasts to exit quiescence. The forced expression of insulin/IGF-like peptides in glia, or activation of PI3K/Akt signaling in neuroblasts, can drive neuroblast growth and proliferation in the absence of dietary protein and thus uncouple neuroblasts from systemic control.
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Drosophila/citología , Drosophila/metabolismo , Células-Madre Neurales/citología , Animales , Dieta , Drosophila/embriología , Cuerpo Adiposo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Neuroglía/citología , Somatomedinas/metabolismoRESUMEN
Zinc deficiency is commonly attributed to inadequate absorption of the metal. Instead, we show that body zinc stores in Drosophila melanogaster depend on tryptophan consumption. Hence, a dietary amino acid regulates zinc status of the whole insecta finding consistent with the widespread requirement of zinc as a protein cofactor. Specifically, the tryptophan metabolite kynurenine is released from insect fat bodies and induces the formation of zinc storage granules in Malpighian tubules, where 3-hydroxykynurenine and xanthurenic acid act as endogenous zinc chelators. Kynurenine functions as a peripheral zinc-regulating hormone and is converted into a 3-hydroxykynureninezincchloride complex, precipitating within the storage granules. Thus, zinc and the kynurenine pathwaywell-known modulators of immunity, blood pressure, aging, and neurodegenerationare physiologically connected.
Asunto(s)
Drosophila melanogaster , Quinurenina , Triptófano , Zinc , Animales , Drosophila melanogaster/metabolismo , Cuerpo Adiposo/metabolismo , Quinurenina/metabolismo , Túbulos de Malpighi/metabolismo , Triptófano/metabolismo , Zinc/metabolismoRESUMEN
Transcription is controlled by interactions of cis-acting DNA elements with diffusible trans-acting factors. Changes in cis or trans factors can drive expression divergence within and between species, and their relative prevalence can reveal the evolutionary history and pressures that drive expression variation. Previous work delineating the mode of expression divergence in animals has largely used whole-body expression measurements in one condition. Because cis-acting elements often drive expression in a subset of cell types or conditions, these measurements may not capture the complete contribution of cis-acting changes. Here, we quantify the mode of expression divergence in the Drosophila fat body, the primary immune organ, in several conditions, using two geographically distinct lines of D. melanogaster and their F1 hybrids. We measured expression in the absence of infection and in infections with Gram-negative S. marcescens or Gram-positive E. faecalis bacteria, which trigger the two primary signaling pathways in the Drosophila innate immune response. The mode of expression divergence strongly depends on the condition, with trans-acting effects dominating in response to Gram-negative infection and cis-acting effects dominating in Gram-positive and preinfection conditions. Expression divergence in several receptor proteins may underlie the infection-specific trans effects. Before infection, when the fat body has a metabolic role, there are many compensatory effects, changes in cis and trans that counteract each other to maintain expression levels. This work shows that within a single tissue, the mode of expression divergence varies between conditions and suggests that these differences reflect the diverse evolutionary histories of host-pathogen interactions.
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Proteínas de Drosophila , Drosophila , Cuerpo Adiposo , Expresión Génica , Animales , Infecciones Bacterianas/genética , Evolución Biológica , Drosophila/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Cuerpo Adiposo/inmunología , Cuerpo Adiposo/metabolismo , Secuencias Reguladoras de Ácidos NucleicosRESUMEN
Studies in mammals and Drosophila have demonstrated the existence and significance of secreted factors involved in communication between distal organs. In this review, primarily focusing on Drosophila, we examine the known interorgan communication factors and their functions, physiological inducers, and integration in regulating physiology. Moreover, we describe how organ-sensing screens in Drosophila can systematically identify novel conserved interorgan communication factors. Finally, we discuss how interorgan communication enabled and evolved as a result of specialization of organs. Together, we anticipate that future studies will establish a model for metazoan interorgan communication network (ICN) and how it is deregulated in disease.
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Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Adipoquinas/metabolismo , Animales , Evolución Biológica , Drosophila/genética , Proteínas de Drosophila/genética , Cuerpo Adiposo/metabolismo , Mamíferos/metabolismo , Neuropéptidos/metabolismo , Transducción de SeñalRESUMEN
Toll/Toll-like receptors (TLRs) are key regulators of the innate immune system in both invertebrates and vertebrates. However, while mammalian TLRs directly recognize pathogen-associated molecular patterns, the insect Toll pathway is thought to be primarily activated by binding Spätzle cytokines that are processed from inactive precursors in response to microbial infection. Phylogenetic and structural data generated in this study supported earlier results showing that Toll9 members differ from other insect Tolls by clustering with the mammalian TLR4 group, which recognizes lipopolysaccharide (LPS) through interaction with myeloid differentiation-2 (MD-2)-like proteins. Functional experiments showed that BmToll9 from the silkmoth Bombyx mori also recognized LPS through interaction with two MD-2-like proteins, previously named BmEsr16 and BmPP, that we refer to in this study as BmMD-2A and BmMD-2B, respectively. A chimeric BmToll9-TLR4 receptor consisting of the BmToll9 ectodomain and mouse TLR4 transmembrane and Toll/interleukin-1 (TIR) domains also activated LPS-induced release of inflammatory factors in murine cells but only in the presence of BmMD-2A or BmMD-2B. Overall, our results indicate that BmToll9 is a pattern recognition receptor for LPS that shares conserved features with the mammalian TLR4-MD-2-LPS pathway.
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Bombyx/metabolismo , Proteínas de Insectos/metabolismo , Mamíferos/metabolismo , Receptores de Reconocimiento de Patrones/metabolismo , Receptor Toll-Like 4/metabolismo , Receptor Toll-Like 9/metabolismo , Animales , Péptidos Antimicrobianos/genética , Bombyx/citología , Bombyx/genética , Línea Celular , Cuerpo Adiposo/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Hemocitos/metabolismo , Humanos , Proteínas de Insectos/genética , Lipopolisacáridos/farmacología , Mamíferos/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Unión Proteica , Células RAW 264.7 , Receptores de Reconocimiento de Patrones/genética , Receptor Toll-Like 4/genética , Receptor Toll-Like 9/genéticaRESUMEN
Dysregulation of collagen production and secretion contributes to aging and tissue fibrosis of major organs. How procollagen proteins in the endoplasmic reticulum (ER) route as specialized cargos for secretion remains to be fully elucidated. Here, we report that TMEM39, an ER-localized transmembrane protein, regulates production and secretory cargo trafficking of procollagen. We identify the C. elegans ortholog TMEM-39 from an unbiased RNAi screen and show that deficiency of tmem-39 leads to striking defects in cuticle collagen production and constitutively high ER stress response. RNAi knockdown of the tmem-39 ortholog in Drosophila causes similar defects in collagen secretion from fat body cells. The cytosolic domain of human TMEM39A binds to Sec23A, a vesicle coat protein that drives collagen secretion and vesicular trafficking. TMEM-39 regulation of collagen secretion is independent of ER stress response and autophagy. We propose that the roles of TMEM-39 in collagen secretion and ER homeostasis are likely evolutionarily conserved.
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Vesículas Cubiertas por Proteínas de Revestimiento/metabolismo , Caenorhabditis elegans/metabolismo , Colágeno/metabolismo , Drosophila/metabolismo , Estrés del Retículo Endoplásmico/genética , Proteínas de la Membrana/metabolismo , Animales , Autofagia/genética , Vesículas Cubiertas por Proteínas de Revestimiento/genética , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Drosophila/genética , Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Cuerpo Adiposo/metabolismo , Técnicas de Silenciamiento del Gen , Aparato de Golgi/metabolismo , Células HeLa , Humanos , Unión Proteica , Transporte de Proteínas/genética , Interferencia de ARN , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismoRESUMEN
Female mosquitoes transmit numerous devastating human diseases because they require vertebrate blood meal for egg development. MicroRNAs (miRNAs) play critical roles across multiple reproductive processes in female Aedes aegypti mosquitoes. However, how miRNAs are controlled to coordinate their activity with the demands of mosquito reproduction remains largely unknown. We report that the ecdysone receptor (EcR)-mediated 20-hydroxyecdysone (20E) signaling regulates miRNA expression in female mosquitoes. EcR RNA-interference silencing linked to small RNA-sequencing analysis reveals that EcR not only activates but also represses miRNA expression in the female mosquito fat body, a functional analog of the vertebrate liver. EcR directly represses the expression of clustered miR-275 and miR-305 before blood feeding when the 20E titer is low, whereas it activates their expression in response to the increased 20E titer after a blood meal. Furthermore, we find that SMRTER, an insect analog of the vertebrate nuclear receptor corepressors SMRT and N-CoR, interacts with EcR in a 20E-sensitive manner and is required for EcR-mediated repression of miRNA expression in Ae. aegypti mosquitoes. In addition, we demonstrate that miR-275 and miR-305 directly target glutamate semialdehyde dehydrogenase and AAEL009899, respectively, to facilitate egg development. This study reveals a mechanism for how miRNAs are controlled by the 20E signaling pathway to coordinate their activity with the demands of mosquito reproduction.
Asunto(s)
Aedes/genética , Dengue/parasitología , Ecdisterona/farmacología , MicroARNs/genética , Mosquitos Vectores/genética , Receptores de Esteroides/metabolismo , Aedes/efectos de los fármacos , Animales , Proteínas Co-Represoras/genética , Proteínas Co-Represoras/metabolismo , Cuerpo Adiposo/efectos de los fármacos , Cuerpo Adiposo/metabolismo , Conducta Alimentaria/efectos de los fármacos , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Histona Desacetilasas/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , MicroARNs/metabolismo , Mosquitos Vectores/efectos de los fármacos , Sistemas de Lectura Abierta/genética , Óvulo/crecimiento & desarrollo , Regiones Promotoras Genéticas/genética , Sitio de Iniciación de la Transcripción , Transcripción Genética/efectos de los fármacos , Transcriptoma/genéticaRESUMEN
Until recently, chemical pesticides were one of the most effective means of controlling agricultural pests; therefore, the search for insecticide targets for agricultural pests has been an ongoing problem. Estrogen-related receptors (ERRs) are transcription factors that regulate cellular metabolism and energy homeostasis in animals. Silkworms are highly sensitive to chemical pesticides, making them ideal models for pesticide screening and evaluation. In this study, we detected ERR expression in key organs involved in pesticide metabolism in silkworms (Bombyx mori), including the fat body and midgut. Using ChIP-seq technology, many estrogen- related response elements were identified in the 2000-bp promoter region upstream of metabolism-related genes, almost all of which were potential ERR target genes. The ERR inhibitor, XCT-790, and the endocrine disruptor, bisphenol A, significantly inhibited expression of the ERR target genes, BmTreh-1, BmTret-1, BmPK, BmPFK, and BmHK, in the fat bodies of silkworms, resulting in pupation difficulties in silkworm larvae that ultimately lead to death. In addition, based on the clarification that the ERR can bind to XCT-790, as observed through biofilm interferometry, its three-dimensional spatial structure was predicted, and using molecular docking techniques, small-molecule compounds with a stronger affinity for the ERR were identified. In summary, utilizing the powerful metabolic regulatory function of ERR in Lepidoptera pests, the developed small molecule inhibitors of ERR can be used for future control of Lepidoptera pests.
Asunto(s)
Bombyx , Simulación del Acoplamiento Molecular , Fenoles , Receptores de Estrógenos , Animales , Receptores de Estrógenos/metabolismo , Receptores de Estrógenos/genética , Bombyx/metabolismo , Bombyx/genética , Bombyx/efectos de los fármacos , Fenoles/farmacología , Compuestos de Bencidrilo/farmacología , Larva/metabolismo , Larva/efectos de los fármacos , Larva/genética , Insecticidas/farmacología , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Cuerpo Adiposo/metabolismo , Cuerpo Adiposo/efectos de los fármacos , Disruptores Endocrinos/farmacología , Disruptores Endocrinos/metabolismo , Nitrilos , TiazolesRESUMEN
BACKGROUND: Endoreplication is involved in the development and function of many organs, the pathologic process of several diseases. However, the metabolic underpinnings and regulation of endoreplication have yet to be well clarified. RESULTS: Here, we showed that a zinc transporter fear-of-intimacy (foi) is necessary for Drosophila fat body endoreplication. foi knockdown in the fat body led to fat body cell nuclei failure to attain standard size, decreased fat body size and pupal lethality. These phenotypes could be modulated by either altered expression of genes involved in zinc metabolism or intervention of dietary zinc levels. Further studies indicated that the intracellular depletion of zinc caused by foi knockdown results in oxidative stress, which activates the ROS-JNK signaling pathway, and then inhibits the expression of Myc, which is required for tissue endoreplication and larval growth in Drosophila. CONCLUSIONS: Our results indicated that FOI is critical in coordinating fat body endoreplication and larval growth in Drosophila. Our study provides a novel insight into the relationship between zinc and endoreplication in insects and may provide a reference for relevant mammalian studies.