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Leyria J, Fruttero LL, Canavoso LE. Lipids in Insect Reproduction: Where, How, and Why. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024. [PMID: 38874891 DOI: 10.1007/5584_2024_809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Modern insects have inhabited the earth for hundreds of millions of years, and part of their successful adaptation lies in their many reproductive strategies. Insect reproduction is linked to a high metabolic rate that provides viable eggs in a relatively short time. In this context, an accurate interplay between the endocrine system and the nutrients synthetized and metabolized is essential to produce healthy offspring. Lipids guarantee the metabolic energy needed for egg formation and represent the main energy source consumed during embryogenesis. Lipids availability is tightly regulated by a complex network of endocrine signals primarily controlled by the central nervous system (CNS) and associated endocrine glands, the corpora allata (CA) and corpora cardiaca (CC). This endocrine axis provides hormones and neuropeptides that significatively affect tissues closely involved in successful reproduction: the fat body, which is the metabolic center supplying the lipid resources and energy demanded in egg formation, and the ovaries, where the developing oocytes recruit lipids that will be used for optimal embryogenesis. The post-genomic era and the availability of modern experimental approaches have advanced our understanding of many processes involved in lipid homeostasis; therefore, it is crucial to integrate the findings of recent years into the knowledge already acquired in the last decades. The present chapter is devoted to reviewing major recent contributions made in elucidating the impact of the CNS/CA/CC-fat body-ovary axis on lipid metabolism in the context of insect reproduction, highlighting areas of fruitful research.
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Affiliation(s)
- Jimena Leyria
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Leonardo L Fruttero
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Lilián E Canavoso
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina.
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
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Zhao Y, Liu W, Zhao X, Yu Z, Guo H, Yang Y, Moussian B, Zhu KY, Zhang J. Lipophorin receptor is required for the accumulations of cuticular hydrocarbons and ovarian neutral lipids in Locusta migratoria. Int J Biol Macromol 2023; 236:123746. [PMID: 36806776 DOI: 10.1016/j.ijbiomac.2023.123746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023]
Abstract
Lipophorin is the most abundant lipoprotein particle in insect hemolymph. Lipophorin receptor (LPR) is a glycoprotein that binds to the lipophorin and mediates cellular uptake and metabolism of lipids by endocytosis. However, the roles of LPR in uptake of lipids in the integument and ovary remain unknown in the migratory locust (Locusta migratoria). In present study, we characterized the molecular properties and biological roles of LmLPR in L. migratoria. The LmLPR transcript level was high in the first 2 days of the adults after eclosion, then gradually declined. LmLPR was predominately expressed in fat body, ovary and integument. Using immuno-detection methods, we revealed that LmLPR was mainly localized in the membrane of oenocytes, epidermal cells, fat body cells and follicular cells. RNAi-mediated silencing of LmLPR led to a slight decrease of the cuticle hydrocarbon contents but with little effect on the cuticular permeability. However, the neutral lipid content was significantly decreased in the ovary after RNAi against LmLPR, which led to a retarded ovarian development. Taken together, our results indicated that LmLPR is involved in the uptake and accumulation of lipids in the ovary and plays a crucial role in ovarian development in L. migratoria. Therefore, LmLPR could be a promising RNAi target for insect pest management by disrupting insect ovarian development.
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Affiliation(s)
- Yiyan Zhao
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China; College of Life Science, Shanxi University, Taiyuan, China
| | - Weimin Liu
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China.
| | - Xiaoming Zhao
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Zhitao Yu
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Hongfang Guo
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China; College of Life Science, Shanxi University, Taiyuan, China
| | - Yang Yang
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China; College of Life Science, Shanxi University, Taiyuan, China
| | - Bernard Moussian
- Interfaculty Institute of Cell Biology, University of Tübingen, 72076 Tübingen, Germany; Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech, 06903 Sophia Antipolis CEDEX, France
| | - Kun Yan Zhu
- Department of Entomology, 123 Waters Hall, Kansas State University, Manhattan, KS 66506, USA
| | - Jianzhen Zhang
- Research Institute of Applied Biology, Shanxi Key Laboratory of Nucleic Acid Biopesticides, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, China.
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Dong X, Chen J, Xu R, Li X, Wang Y, Pan X, Zhang C, Li Y, Wang F, Li C. Molecular identification and lipid mobilization role of adipokinetic hormone receptor in Spodoptera litura (F.). BULLETIN OF ENTOMOLOGICAL RESEARCH 2022; 112:758-765. [PMID: 35431022 DOI: 10.1017/s0007485322000141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Energy homeostasis is essential for organisms to maintain fluctuation in energy accumulation, mobilization. Lipids as the main energy reserve in insects, their metabolism is under the control of many physiological program. This study aimed to determine whether the adipokinetic hormone receptor (AKHR) was involved in the lipid mobilization in the Spodoptera litura. A full-length cDNA encoding AKHR was isolated from S. litura. The SlAKHR protein has a conserved seven-transmembrane domain which is the character of a putative G protein receptor. Expression profile investigation revealed that SlAKHR mRNA was highly expressed in immatural stage and abundant in fat body in newly emerged female adults. Knockdown of SlAKHR expression was achieved through RNAi by injecting double-stranded RNA (dsRNA) into the 6th instar larvae. The content of triacylgycerol (TAG) in the fat body increased significantly after the SlAKHR gene was knockdown. And decrease of TAG releasing to hemolymph with increase of free fatty acid (FFA) in hemolymph were observed when the SlAKHR gene was knowned-down. In addition, lipid droplets increased in fat body was also found. These results suggested that SlAKHR is critical for insects to regulate lipids metabolism.
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Affiliation(s)
- Xiaolin Dong
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
- Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
| | - Junyuan Chen
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
| | - Rubing Xu
- Tobacco Research Institute of Hubei Province, Wuhan 430002, Hubei, China
| | - Xihong Li
- Tobacco Research Institute of Hubei Province, Wuhan 430002, Hubei, China
| | - Yang Wang
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
| | - Xue Pan
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
| | - Cuici Zhang
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
| | - Yanyan Li
- Tobacco Research Institute of Hubei Province, Wuhan 430002, Hubei, China
| | - Fulian Wang
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
| | - Chuanren Li
- Hubei Engineering Research Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou 434025, Hubei, China
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Ramos FO, Nouzova M, Fruttero LL, Leyria J, Ligabue-Braun R, Noriega FG, Canavoso LE. Role of Methoprene-tolerant in the regulation of oogenesis in Dipetalogaster maxima. Sci Rep 2022; 12:14195. [PMID: 35988007 PMCID: PMC9392760 DOI: 10.1038/s41598-022-18384-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/10/2022] [Indexed: 11/12/2022] Open
Abstract
Juvenile hormone (JH) signalling, via its receptor Methoprene-tolerant (Met), controls metamorphosis and reproduction in insects. Met belongs to a superfamily of transcription factors containing the basic Helix Loop Helix (bHLH) and Per Arnt Sim (PAS) domains. Since its discovery in 1986, Met has been characterized in several insect species. However, in spite of the importance as vectors of Chagas disease, our knowledge on the role of Met in JH signalling in Triatominae is limited. In this study, we cloned and sequenced the Dipetalogaster maxima Met transcript (DmaxMet). Molecular modelling was used to build the structure of Met and identify the JH binding site. To further understand the role of the JH receptor during oogenesis, transcript levels were evaluated in two main target organs of JH, fat body and ovary. Functional studies using Met RNAi revealed significant decreases of transcripts for vitellogenin (Vg) and lipophorin (Lp), as well as their receptors. Lp and Vg protein amounts in fat body, as well as Vg in hemolymph were also decreased, and ovarian development was impaired. Overall, these studies provide additional molecular insights on the roles of JH signalling in oogenesis in Triatominae; and therefore are relevant for the epidemiology of Chagas´ disease.
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Affiliation(s)
- Fabian O Ramos
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Marcela Nouzova
- Department of Biological Sciences and Biomolecular Science Institute, Florida International University, Miami, FL, USA
- Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech Republic
| | - Leonardo L Fruttero
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Jimena Leyria
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Rodrigo Ligabue-Braun
- Department of Pharmacosciences and Graduate Program in Biosciences (PPGBio), Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil
| | - Fernando G Noriega
- Department of Biological Sciences and Biomolecular Science Institute, Florida International University, Miami, FL, USA.
- Department of Parasitology, University of South Bohemia, Ceske Budejovice, Czech Republic.
| | - Lilian E Canavoso
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
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Kaczmarek A, Boguś M. The metabolism and role of free fatty acids in key physiological processes in insects of medical, veterinary and forensic importance. PeerJ 2021; 9:e12563. [PMID: 35036124 PMCID: PMC8710053 DOI: 10.7717/peerj.12563] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 11/07/2021] [Indexed: 12/16/2022] Open
Abstract
Insects are the most widespread group of organisms and more than one million species have been described. These animals have significant ecological functions, for example they are pollinators of many types of plants. However, they also have direct influence on human life in different manners. They have high medical and veterinary significance, stemming from their role as vectors of disease and infection of wounds and necrotic tissue; they are also plant pests, parasitoids and predators whose activities can influence agriculture. In addition, their use in medical treatments, such as maggot therapy of gangrene and wounds, has grown considerably. They also have many uses in forensic science to determine the minimum post-mortem interval and provide valuable information about the movement of the body, cause of the death, drug use, or poisoning. It has also been proposed that they may be used as model organisms to replace mammal systems in research. The present review describes the role of free fatty acids (FFAs) in key physiological processes in insects. By focusing on insects of medical, veterinary significance, we have limited our description of the physiological processes to those most important from the point of view of insect control; the study examines their effects on insect reproduction and resistance to the adverse effects of abiotic (low temperature) and biotic (pathogens) factors.
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Affiliation(s)
- Agata Kaczmarek
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
| | - Mieczysława Boguś
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Warsaw, Poland
- Biomibo, Warsaw, Poland
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6
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Qiao JW, Fan YL, Bai TT, Wu BJ, Pei XJ, Wang D, Liu TX. Lipophorin receptor regulates the cuticular hydrocarbon accumulation and adult fecundity of the pea aphid Acyrthosiphon pisum. INSECT SCIENCE 2021; 28:1018-1032. [PMID: 32558147 DOI: 10.1111/1744-7917.12828] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/16/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Cuticular hydrocarbons form a barrier that protects terrestrial insects from water loss via the epicuticle. Lipophorin loads and transports lipids, including hydrocarbons, from one tissue to another. In some insects, the lipophorin receptor (LpR), which binds to lipophorin and accepts its lipid cargo, is essential for female fecundity because it mediates the incorporation of lipophorin by developing oocytes. However, it is unclear whether LpR is involved in the accumulation of cuticular hydrocarbons and its precise role in aphid reproduction remains unknown. We herein present the results of our molecular characterization, phylogenetic analysis, and functional annotation of the pea aphid (Acyrthosiphon pisum) LpR gene (ApLpR). This gene was transcribed throughout the A. pisum life cycle, but especially during the embryonic stage and in the abdominal cuticle. Furthermore, we optimized the RHA interference (RNAi) parameters by determining the ideal dose and duration for gene silencing in the pea aphid. We observed that the RNAi-based ApLpR suppression significantly decreased the internal and cuticular hydrocarbon contents as well as adult fecundity. Additionally, a deficiency in cuticular hydrocarbons increased the susceptibility of aphids to desiccation stress, with decreased survival rates under simulated drought conditions. Moreover, ApLpR expression levels significantly increased in response to the desiccation treatment. These results confirm that ApLpR is involved in transporting hydrocarbons and protecting aphids from desiccation stress. Furthermore, this gene is vital for aphid reproduction. Therefore, the ApLpR gene of A. pisum may be a novel RNAi target relevant for insect pest management.
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Affiliation(s)
- Jian-Wen Qiao
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
| | - Yong-Liang Fan
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
| | - Tian-Tian Bai
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
| | - Bing-Jin Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiao-Jin Pei
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
| | - Dun Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
| | - Tong-Xian Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China
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Ramos FO, Leyria J, Nouzova M, Fruttero LL, Noriega FG, Canavoso LE. Juvenile hormone mediates lipid storage in the oocytes of Dipetalogaster maxima. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 133:103499. [PMID: 33212190 DOI: 10.1016/j.ibmb.2020.103499] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/20/2020] [Accepted: 11/06/2020] [Indexed: 06/11/2023]
Abstract
Triatomines are vectors of Chagas disease and important model organisms in insect physiology. "Kissing bugs" are obligatory hematophagous insects. A blood meal is required to successfully complete oogenesis, a process primarily controlled by juvenile hormone (JH). We used Dipetalogaster maxima as an experimental model to further understand the roles of JH in the regulation of vitellogenesis and oogenesis. A particular focus was set on the role of JH controlling lipid and protein recruitment by the oocytes. The hemolymph titer of JH III skipped bisepoxide increased after a blood meal. Following a blood meal there were increased levels of mRNAs in the fat body for the yolk protein precursors, vitellogenin (Vg) and lipophorin (Lp), as well as of their protein products in the hemolymph; mRNAs of the Vg and Lp receptors (VgR and LpR) were concomitantly up-regulated in the ovaries. Topical administration of JH induced the expression of Lp/LpR and Vg/VgR genes, and prompted the uptake of Lp and Vg in pre-vitellogenic females. Knockdown of the expression of LpR by RNA interference in fed females did not impair the Lp-mediated lipid transfer to oocytes, suggesting that the bulk of lipid acquisition by oocytes occurred by other pathways rather than by the endocytic Lp/LpR pathway. In conclusion, our results strongly suggest that JH signaling is critical for lipid storage in oocytes, by regulating Vg and Lp gene expression in the fat body as well as by modulating the expression of LpR and VgR genes in ovaries.
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Affiliation(s)
- Fabian O Ramos
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina; Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
| | - Jimena Leyria
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina; Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
| | - Marcela Nouzova
- Department of Biological Sciences and Biomolecular Science Institute, Florida International University, Miami, FL, USA; Institute of Parasitology, Biology Centre CAS, Ceske Budejovice, Czech Republic.
| | - Leonardo L Fruttero
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina; Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
| | - Fernando G Noriega
- Department of Biological Sciences and Biomolecular Science Institute, Florida International University, Miami, FL, USA.
| | - Lilian E Canavoso
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina; Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
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8
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McFarlane M, Laureti M, Levée T, Terry S, Kohl A, Pondeville E. Improved transient silencing of gene expression in the mosquito female Aedes aegypti. INSECT MOLECULAR BIOLOGY 2021; 30:355-365. [PMID: 33715239 DOI: 10.1111/imb.12700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/30/2020] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
Gene silencing using RNA interference (RNAi) has become a widely used genetic technique to study gene function in many organisms. In insects, this technique is often applied through the delivery of dsRNA. In the adult female Aedes aegypti, a main vector of human-infecting arboviruses, efficiency of gene silencing following dsRNA injection varies greatly according to targeted genes. Difficult knockdowns using dsRNA can thus hamper gene function analysis. Here, by analysing silencing of three different genes in female Ae. aegypti (p400, ago2 and E75), we show that gene silencing can indeed be dsRNA sequence dependent but different efficiencies do not correlate with dsRNA length. Our findings suggest that silencing is likely also gene dependent, probably due to gene-specific tissue expression and/or feedback mechanisms. We demonstrate that use of high doses of dsRNA can improve knockdown efficiency, and injection of a transfection reagent along with dsRNA reduces the variability in efficiency between replicates. Finally, we show that gene silencing cannot be achieved using siRNA injection in Ae. aegypti adult females. Overall, this work should help future gene function analyses using RNAi in adult females Ae. aegypti, leading toward a better understanding of physiological and infectious processes.
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Affiliation(s)
- M McFarlane
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - M Laureti
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - T Levée
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - S Terry
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - A Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - E Pondeville
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
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9
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Ventós-Alfonso A, Ylla G, Montañes JC, Belles X. DNMT1 Promotes Genome Methylation and Early Embryo Development in Cockroaches. iScience 2020; 23:101778. [PMID: 33294787 PMCID: PMC7691181 DOI: 10.1016/j.isci.2020.101778] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/08/2020] [Accepted: 11/03/2020] [Indexed: 01/02/2023] Open
Abstract
The influence of DNA methylation on gene behavior and its consequent phenotypic effects appear to be very important, but the details are not well understood. Insects offer a diversity of DNA methylation modes, making them an excellent lineage for comparative analyses. However, functional studies have tended to focus on quite specialized holometabolan species, such as wasps, bees, beetles, and flies. Here, we have studied DNA methylation in the hemimetabolan insect Blattella germanica. In this cockroach, a gene involved in DNA methylation, DNA methyltransferase 1 (DNMT1), is expressed in early embryogenesis. In our experiments, RNAi of DNMT1 reduces DNA methylation and impairs blastoderm formation. Using reduced representation bisulfite sequencing and transcriptome analyses, we observed that methylated genes are associated with metabolism and are highly expressed, whereas unmethylated genes are related to signaling and show low expression. Moreover, methylated genes show greater expression change and less expression variability than unmethylated genes.
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Affiliation(s)
- Alba Ventós-Alfonso
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003, Barcelona, Spain
| | - Guillem Ylla
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003, Barcelona, Spain
| | - Jose-Carlos Montañes
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003, Barcelona, Spain
| | - Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003, Barcelona, Spain
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Toprak U, Hegedus D, Doğan C, Güney G. A journey into the world of insect lipid metabolism. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2020; 104:e21682. [PMID: 32335968 DOI: 10.1002/arch.21682] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Lipid metabolism is fundamental to life. In insects, it is critical, during reproduction, flight, starvation, and diapause. The coordination center for insect lipid metabolism is the fat body, which is analogous to the vertebrate adipose tissue and liver. Fat body contains various different cell types; however, adipocytes and oenocytes are the primary cells related to lipid metabolism. Lipid metabolism starts with the hydrolysis of dietary lipids, absorption of lipid monomers, followed by lipid transport from midgut to the fat body, lipogenesis or lipolysis in the fat body, and lipid transport from fat body to other sites demanding energy. Lipid metabolism is under the control of hormones, transcription factors, secondary messengers and posttranscriptional modifications. Primarily, lipogenesis is under the control of insulin-like peptides that activate lipogenic transcription factors, such as sterol regulatory element-binding proteins, whereas lipolysis is coordinated by the adipokinetic hormone that activates lipolytic transcription factors, such as forkhead box class O and cAMP-response element-binding protein. Calcium is the primary-secondary messenger affecting lipid metabolism and has different outcomes depending on the site of lipogenesis or lipolysis. Phosphorylation is central to lipid metabolism and multiple phosphorylases are involved in lipid accumulation or hydrolysis. Although most of the knowledge of insect lipid metabolism comes from the studies on the model Drosophila; other insects, in particular those with obligatory or facultative diapause, also have great potential to study lipid metabolism. The use of these models would significantly improve our knowledge of insect lipid metabolism.
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Affiliation(s)
- Umut Toprak
- Molecular Entomology Laboratory, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
| | - Dwayne Hegedus
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Cansu Doğan
- Molecular Entomology Laboratory, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
| | - Gözde Güney
- Molecular Entomology Laboratory, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
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Lu K, Zhou J, Chen X, Li W, Li Y, Cheng Y, Yan J, You K, Yuan Z, Zhou Q. Deficiency of Brummer Impaires Lipid Mobilization and JH-Mediated Vitellogenesis in the Brown Planthopper, Nilaparvata lugens. Front Physiol 2018; 9:1535. [PMID: 30425657 PMCID: PMC6218678 DOI: 10.3389/fphys.2018.01535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 10/11/2018] [Indexed: 01/23/2023] Open
Abstract
Provisioning of sufficient lipids and vitellogenin to the oocytes is an indispensable process for fecundity of oviparous insects. Acute mobilization of lipid reserves in insects is controlled by the Brummer (Bmm), an orthologous of human adipose triglyceride lipase (ATGL). To investigate the functional roles of brummer-mediated lipolysis in the fecundity of the brown planthopper, Nilaparvata lugens, RNA interference (RNAi) analyses were performed with double-stranded RNA (dsRNA) against NlBmm in adult females. Knockdown of NlBmm expression resulted in obesity and blocked lipid mobilization in the fat body. In addition, NlBmm silencing led to retarded ovarian development with immature eggs and less ovarioles, decreased number of laid eggs, prolonged preoviposition period and egg duration. Furthermore, severe reductions of vitellogenin and its receptor abundance were observed upon NlBmm knockdown. The transcript levels of NlJHE (juvenile hormone esterase) which degrades JH were up-regulated, whereas the expression levels of JH receptors NlMet (Methoprene-tolerant) and NlTai (Taiman) and their downstream transcription factors NlKr-h1 (Krüppel-homolog 1) and NlBr (Broad-Complex) were down-regulated after suppression of NlBmm. JH-deficient females exhibited impaired vitellogenin expression, whereas JH exposure stimulated vitellogenin biosynthesis. Moreover, JH topical application partially rescued the decrease in vitellogenin expression in the NlBmm-deficient females. These results demonstrate that brummer-mediated lipolytic system is essential for lipid mobilization and energy homeostasis during reproduction in N. lugens. In addition to the classical view of brummer as a direct lipase with lipolysis activity, we propose here that brummer-mediated lipolysis works through JH signaling pathway to activate vitellogenesis and oocyte maturation that in turn regulates female fecundity.
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Affiliation(s)
- Kai Lu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jinming Zhou
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xia Chen
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenru Li
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yue Li
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yibei Cheng
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jing Yan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Keke You
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhineng Yuan
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qiang Zhou
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Gondim KC, Atella GC, Pontes EG, Majerowicz D. Lipid metabolism in insect disease vectors. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 101:108-123. [PMID: 30171905 DOI: 10.1016/j.ibmb.2018.08.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/17/2018] [Accepted: 08/26/2018] [Indexed: 06/08/2023]
Abstract
More than a third of the world population is at constant risk of contracting some insect-transmitted disease, such as Dengue fever, Zika virus disease, malaria, Chagas' disease, African trypanosomiasis, and others. Independent of the life cycle of the pathogen causing the disease, the insect vector hematophagous habit is a common and crucial trait for the transmission of all these diseases. This lifestyle is unique, as hematophagous insects feed on blood, a diet that is rich in protein but relatively poor in lipids and carbohydrates, in huge amounts and low frequency. Another unique feature of these insects is that blood meal triggers essential metabolic processes, as molting and oogenesis and, in this way, regulates the expression of various genes that are involved in these events. In this paper, we review current knowledge of the physiology and biochemistry of lipid metabolism in insect disease vectors, comparing with classical models whenever possible. We address lipid digestion and absorption, hemolymphatic transport, and lipid storage by the fat body and ovary. In this context, both de novo fatty acid and triacylglycerol synthesis are discussed, including the related fatty acid activation process and the intracellular lipid binding proteins. As lipids are stored in order to be mobilized later on, e.g. for flight activity or survivorship, lipolysis and β-oxidation are also considered. All these events need to be finely regulated, and the role of hormones in this control is summarized. Finally, we also review information about infection, when vector insect physiology is affected, and there is a crosstalk between its immune system and lipid metabolism. There is not abundant information about lipid metabolism in vector insects, and significant current gaps in the field are indicated, as well as questions to be answered in the future.
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Affiliation(s)
- Katia C Gondim
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Georgia C Atella
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Emerson G Pontes
- Departamento de Bioquímica, Instituto de Química, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil
| | - David Majerowicz
- Departamento de Biotecnologia Farmacêutica, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Lu K, Chen X, Li Y, Li W, Zhou Q. Lipophorin receptor regulates Nilaparvata lugens fecundity by promoting lipid accumulation and vitellogenin biosynthesis. Comp Biochem Physiol A Mol Integr Physiol 2018; 219-220:28-37. [DOI: 10.1016/j.cbpa.2018.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/25/2018] [Accepted: 02/14/2018] [Indexed: 10/18/2022]
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Khan MT, Dalvin S, Waheed Q, Nilsen F, Male R. Molecular characterization of the lipophorin receptor in the crustacean ectoparasite Lepeophtheirus salmonis. PLoS One 2018; 13:e0195783. [PMID: 29649335 PMCID: PMC5897026 DOI: 10.1371/journal.pone.0195783] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 03/29/2018] [Indexed: 12/11/2022] Open
Abstract
The Salmon louse (Lepeophtheirus salmonis) is a marine ectoparasite of salmonid fish in the Northern Hemisphere and considered as a major challenge in aquaculture and a threat to wild populations of salmonids. Adult female lice produce a large number of lipid-rich eggs, however, the mechanism of maternal lipid transport into developing eggs during salmon louse reproduction has not been described. In the present study, a full-length L. salmonis lipophorin receptor (LsLpR) consisting of 16 exons was obtained by RACE and RT-PCR. The predicted ORF was 952 amino acids and structural analysis showed five functional domains that are similar to LpR of insects and decapods. Phylogenetic analysis placed the LsLpR together with LpRs from decapods and insects. Expression analysis revealed that the relative abundance of LsLpR transcripts was highest in the larvae and adult female lice. In adult females, the LsLpR transcripts and protein were found in the ovary and vitellogenic oocytes whereas, in larvae, the LsLpR transcripts were found in the neuronal somata of the brain and the intestine. Oil Red O stain results revealed that storage of neutral lipids was found in vitellogenic oocytes and ovaries of adult females, and in the yolk of larvae. Moreover, RNA interference (RNAi) was conducted to demonstrate the function of LsLpR in reproduction and lipid metabolism in L. salmonis. In larvae, the transcription of LsLpR was decreased by 44–54% while in an experiment LsLpR knockdown female lice produced 72% less offspring than control lice.
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Affiliation(s)
- Muhammad Tanveer Khan
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Sussie Dalvin
- Sea Lice Research Centre, Institute of Marine Research, Bergen, Norway
| | - Qaiser Waheed
- Computational Biology Unit, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Frank Nilsen
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Rune Male
- Computational Biology Unit, Department of Biological Sciences, University of Bergen, Bergen, Norway
- * E-mail:
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Cao M, Gatehouse JA, Fitches EC. A Systematic Study of RNAi Effects and dsRNA Stability in Tribolium castaneum and Acyrthosiphon pisum, Following Injection and Ingestion of Analogous dsRNAs. Int J Mol Sci 2018; 19:E1079. [PMID: 29617308 PMCID: PMC5979293 DOI: 10.3390/ijms19041079] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 03/28/2018] [Accepted: 03/30/2018] [Indexed: 01/29/2023] Open
Abstract
RNA interference (RNAi) effects in insects are highly variable and may be largely dependent upon the stability of introduced double-stranded RNAs to digestion by nucleases. Here, we report a systematic comparison of RNAi effects in susceptible red flour beetle (Tribolium castaneum) and recalcitrant pea aphid (Acyrthosiphon pisum) following delivery of dsRNAs of identical length targeting expression of V-type ATPase subunit E (VTE) and inhibitor of apoptosis (IAP) genes. Injection and ingestion of VTE and IAP dsRNAs resulted in up to 100% mortality of T. castaneum larvae and sustained suppression (>80%) of transcript levels. In A. pisum, injection of VTE but not IAP dsRNA resulted in up to 65% mortality and transient suppression (ca. 40%) of VTE transcript levels. Feeding aphids on VTE dsRNA reduced growth and fecundity although no evidence for gene suppression was obtained. Rapid degradation of dsRNAs by aphid salivary, haemolymph and gut nucleases contrasted with stability in T. castaneum larvae where it appears that exo-nuclease activity is responsible for relatively slow digestion of dsRNAs. This is the first study to directly compare RNAi effects and dsRNA stability in receptive and refractory insect species and provides further evidence that dsRNA susceptibility to nucleases is a key factor in determining RNAi efficiency.
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Affiliation(s)
- Min Cao
- Department of Biosciences, Durham University, Durham DH1 3LE, UK.
| | - John A Gatehouse
- Department of Biosciences, Durham University, Durham DH1 3LE, UK.
| | - Elaine C Fitches
- Department of Biosciences, Durham University, Durham DH1 3LE, UK.
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16
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Fruttero LL, Leyria J, Ramos FO, Stariolo R, Settembrini BP, Canavoso LE. The process of lipid storage in insect oocytes: The involvement of β-chain of ATP synthase in lipophorin-mediated lipid transfer in the chagas' disease vector Panstrongylus megistus (Hemiptera: Reduviidae). JOURNAL OF INSECT PHYSIOLOGY 2017; 96:82-92. [PMID: 27983943 DOI: 10.1016/j.jinsphys.2016.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/18/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
Lipophorin is the main lipoprotein in the hemolymph of insects. During vitellogenesis, lipophorin delivers its hydrophobic cargo to developing oocytes by its binding to non-endocytic receptors at the plasma membrane of the cells. In some species however, lipophorin may also be internalized to some extent, thus maximizing the storage of lipid resources in growing oocytes. The ectopic β chain of ATP synthase (β-ATPase) was recently described as a putative non-endocytic lipophorin receptor in the anterior midgut of the hematophagous insect Panstrongylus megistus. In the present work, females of this species at the vitellogenic stage of the reproductive cycle were employed to investigate the role of β-ATPase in the transfer of lipids to the ovarian tissue. Subcellular fractionation and western blot revealed the presence of β-ATPase in the microsomal membranes of the ovarian tissue, suggesting its localization in the plasma membrane. Immunofluorescence assays showed partial co-localization of β-ATPase and lipophorin in the membrane of oocytes as well as in the basal domain of the follicular epithelial cells. Ligand blotting and co-immunoprecipitation approaches confirmed the interaction between lipophorin and β-ATPase. In vivo experiments with an anti-β-ATPase antibody injected to block such an interaction demonstrated that the antibody significantly impaired the transfer of fatty acids from lipophorin to the oocyte. However, the endocytic pathway of lipophorin was not affected. On the other hand, partial inhibition of ATP synthase activity did not modify the transfer of lipids from lipophorin to oocytes. When the assays were performed at 4°C to diminish endocytosis, the results showed that the antibody interfered with lipophorin binding to the oocyte plasma membrane as well as with the transfer of fatty acids from the lipoprotein to the oocyte. The findings strongly support that β-ATPase plays a role as a docking lipophorin receptor at the ovary of P. megistus, similarly to its function in the midgut of such a vector. In addition, the role of β-ATPase as a docking receptor seems to be independent of the enzymatic ATP synthase activity.
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Affiliation(s)
- Leonardo L Fruttero
- Dpto. Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Jimena Leyria
- Dpto. Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Fabián O Ramos
- Dpto. Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Raúl Stariolo
- Coordinación Nacional de Control de Vectores, Servicio Nacional de Chagas. Santa María de Punilla, Córdoba, Argentina
| | - Beatriz P Settembrini
- Facultad de Ciencias Biomédicas, Universidad Austral, Pilar, Provincia de Buenos Aires, Argentina; Museo Argentino de Ciencias Naturales, Ciudad Autónoma de Buenos Aires, Argentina
| | - Lilián E Canavoso
- Dpto. Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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17
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Fruttero LL, Leyria J, Canavoso LE. Lipids in Insect Oocytes: From the Storage Pathways to Their Multiple Functions. Results Probl Cell Differ 2017; 63:403-434. [PMID: 28779328 DOI: 10.1007/978-3-319-60855-6_18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In insect physiology, the mechanisms involved in the buildup and regulation of yolk proteins in developing oocytes have been thoroughly researched during the last three decades. Comparatively, the study of lipid metabolism in oocytes had received less attention. The importance of this issue lies in the fact that lipids make up to 40% of the dry weight of an insect egg, being the most important supply of energy for the developing embryo. Since the oocyte has a very limited capacity to synthesize lipids de novo, most of the lipids in the mature eggs arise from the circulation. The main lipid carriers in the insect circulatory system are the lipoproteins lipophorin and vitellogenin. In some species, the endocytosis of lipophorin and vitellogenin may account for about 10% of the lipids present in mature eggs. Thus, most of the lipids are transferred by a lipophorin-mediated pathway, in which the lipoprotein unloads its lipid cargo at the surface of oocytes without internalization. This chapter recapitulates the current status on lipid storage and its utilization in insect oocytes and discusses the participation of key factors including lipoproteins, transfer proteins, lipolytic enzymes, and dynamic organelles such as lipid droplets. The new findings in the field of lipophorin receptors are presented in the context of lipid accumulation during egg maturation, and the roles of lipids beyond energy source are summarized from the perspective of oogenesis and embryogenesis. Finally, prospective and fruitful areas of future research are suggested.
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Affiliation(s)
- Leonardo L Fruttero
- Instituto do Cerebro (InsCer). Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Jimena Leyria
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina
| | - Lilián E Canavoso
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina.
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Coelho RR, de Souza Júnior JDA, Firmino AAP, de Macedo LLP, Fonseca FCA, Terra WR, Engler G, de Almeida Engler J, da Silva MCM, Grossi-de-Sa MF. Vitellogenin knockdown strongly affects cotton boll weevil egg viability but not the number of eggs laid by females. Meta Gene 2016; 9:173-80. [PMID: 27419079 PMCID: PMC4936639 DOI: 10.1016/j.mgene.2016.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/23/2016] [Indexed: 12/18/2022] Open
Abstract
Vitellogenin (Vg), a yolk protein precursor, is the primary egg nutrient source involved in insect reproduction and embryo development. The Cotton Boll weevil (CBW) Anthonomus grandis Boheman, the most important cotton pest in Americas, accumulates large amounts of Vg during reproduction. However, the precise role of this protein during embryo development in this insect remains unknown. Herein, we investigated the effects of vitellogenin (AgraVg) knockdown on the egg-laying and egg viability in A. grandis females, and also characterized morphologically the unviable eggs. AgraVg transcripts were found during all developmental stages of A. grandis, with highest abundance in females. Silencing of AgraVg culminated in a significant reduction in transcript amount, around 90%. Despite this transcriptional reduction, egg-laying was not affected in dsRNA-treated females but almost 100% of the eggs lost their viability. Eggs from dsRNA-treated females showed aberrant embryos phenotype suggesting interference at different stages of embryonic development. Unlike for other insects, the AgraVg knockdown did not affect the egg-laying ability of A. grandis, but hampered A. grandis reproduction by perturbing embryo development. We concluded that the Vg protein is essential for A. grandis reproduction and a good candidate to bio-engineer the resistance against this devastating cotton pest.
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Affiliation(s)
- Roberta R Coelho
- University of Brasília, Brasília, DF, Brazil; Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil
| | | | - Alexandre A P Firmino
- Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil; Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Leonardo L P de Macedo
- Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil; Catholic University of Brasília, Brasília, DF, Brazil
| | - Fernando C A Fonseca
- University of Brasília, Brasília, DF, Brazil; Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil
| | | | - Gilbert Engler
- Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil; Institut National de la Recherche Agronomique, Sophia-Antipolis, France
| | - Janice de Almeida Engler
- Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil; Institut National de la Recherche Agronomique, Sophia-Antipolis, France
| | | | - Maria Fatima Grossi-de-Sa
- Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil; Catholic University of Brasília, Brasília, DF, Brazil
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Molecular Characterization and Function Analysis of the Vitellogenin Receptor from the Cotton Bollworm, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae). PLoS One 2016; 11:e0155785. [PMID: 27192057 PMCID: PMC4871585 DOI: 10.1371/journal.pone.0155785] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/04/2016] [Indexed: 11/19/2022] Open
Abstract
Developing oocytes accumulate plentiful yolk protein during oogenesis through receptor-mediated endocytosis. The vitellogenin receptor (VgR), belonging to the low-density lipoprotein receptor (LDLR) family, regulates the absorption of yolk protein. In this work, the full-length vitellogenin receptor (HaVgR) in the cotton bollworm Helicoverpa armigera was identified, encoding a 1817 residue protein. Sequence alignment revealed that the sequence of HaVgR contained all of the conservative structural motifs of LDLR family members, and phylogenetic analysis indicated that HaVgR had a high identity among Lepidoptera and was distinct from that of other insects. Consistent with other insects, HaVgR was specifically expressed in ovarian tissue. The developmental expression pattern showed that HaVgR was first transcribed in the newly metamorphosed female adults, reached a peak in 2-day-old adults and then declined. Western blot analysis also revealed an ovarian-specific and developing expression pattern, which was consistent with the HaVgR mRNA transcription. Moreover, RNAi-mediated HaVgR knockdown strongly reduced the VgR expression in both the mRNA and protein levels, which inhibited the yolk protein deposition in the ovaries, led to the dramatic accumulation of vitellogenin and the up-regulation of HaVg expression in hemolymph, and eventually resulted in a declined fecundity. Together, all of these findings demonstrate that HaVgR is a specific receptor in uptake and transportation of yolk protein for the maturation of oocytes and that it plays a critical role in female reproduction.
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Van der Horst DJ, Rodenburg KW. Lipoprotein assembly and function in an evolutionary perspective. Biomol Concepts 2015; 1:165-83. [PMID: 25961995 DOI: 10.1515/bmc.2010.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Circulatory fat transport in animals relies on members of the large lipid transfer protein (LLTP) superfamily, including mammalian apolipoprotein B (apoB) and insect apolipophorin II/I (apoLp-II/I). ApoB and apoLp-II/I, constituting the structural (non-exchangeable) basis for the assembly of various lipoproteins, acquire lipids through microsomal triglyceride-transfer protein, another LLTP family member, and bind them by means of amphipathic α-helical and β-sheet structural motifs. Comparative research reveals that LLTPs evolved from the earliest animals and highlights the structural adaptations in these lipid-binding proteins. Thus, in contrast to apoB, apoLp-II/I is cleaved post-translationally by a furin, resulting in the appearance of two non-exchangeable apolipoproteins in the single circulatory lipoprotein in insects, high-density lipophorin (HDLp). The remarkable structural similarities between mammalian and insect lipoproteins notwithstanding important functional differences relate to the mechanism of lipid delivery. Whereas in mammals, partial delipidation of apoB-containing lipoproteins eventually results in endocytic uptake of their remnants, mediated by members of the low-density lipoprotein receptor (LDLR) family, and degradation in lysosomes, insect HDLp functions as a reusable lipid shuttle capable of alternate unloading and reloading of lipid. Also, during muscular efforts (flight activity), an HDLp-based lipoprotein shuttle provides for the transport of lipid for energy generation. Although a lipophorin receptor - a homolog of LDLR - was identified that mediates endocytic uptake of HDLp during specific developmental periods, the endocytosed lipoprotein appears to be recycled in a transferrin-like manner. These data highlight that the functional adaptations in the lipoprotein lipid carriers in mammals and insects also emerge with regard to the functioning of their cognate receptors.
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Irles P, Piulachs MD. Unlike in Drosophila Meroistic Ovaries, hippo represses notch in Blattella germanica Panoistic ovaries, triggering the mitosis-endocycle switch in the follicular cells. PLoS One 2014; 9:e113850. [PMID: 25426635 PMCID: PMC4245235 DOI: 10.1371/journal.pone.0113850] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 11/02/2014] [Indexed: 11/29/2022] Open
Abstract
During insect oogenesis, the follicular epithelium undergoes both cell proliferation and apoptosis, thus modulating ovarian follicle growth. The Hippo pathway is key in these processes, and has been thoroughly studied in the meroistic ovaries of Drosophila melanogaster. However, nothing is known about the role of the Hippo pathway in primitive panoistic ovaries. This work examines the mRNA expression levels of the main components of the Hippo pathway in the panoistic ovary of the basal insect species Blattella germanica, and demonstrates the function of Hippo through RNAi. In Hippo-depleted specimens, the follicular cells of the basal ovarian follicles proliferate without arresting cytokinesis; the epithelium therefore becomes bilayered, impairing ovarian follicle growth. This phenotype is accompanied by long stalks between the ovarian follicles. In D. melanogaster loss of function of Notch determines that the stalk is not developed. With this in mind, we tested whether Hippo and Notch pathways are related in B. germanica. In Notch (only)-depleted females, no stalks were formed between the ovarian follicles. Simultaneous depletion of Hippo and Notch rescued partially the stalk to wild-type. Unlike in the meroistic ovaries of D. melanogaster, in panoistic ovaries the Hippo pathway appears to regulate follicular cell proliferation by acting as a repressor of Notch, triggering the switch from mitosis to the endocycle in the follicular cells. The phylogenetically basal position of B. germanica suggests that this might be the ancestral function of Hippo in insect ovaries.
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Affiliation(s)
- Paula Irles
- Institut de Biologia Evolutiva (CSIC - Universitat Pompeu Fabra), Barcelona, Spain
| | - Maria-Dolors Piulachs
- Institut de Biologia Evolutiva (CSIC - Universitat Pompeu Fabra), Barcelona, Spain
- * E-mail:
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Wynant N, Santos D, Vanden Broeck J. Biological mechanisms determining the success of RNA interference in insects. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 312:139-67. [PMID: 25262241 DOI: 10.1016/b978-0-12-800178-3.00005-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Insects constitute the largest group of animals on this planet, having a huge impact on our environment, as well as on our quality of life. RNA interference (RNAi) is a posttranscriptional gene silencing mechanism triggered by double-stranded (ds)RNA fragments. This process not only forms the basis of a widely used reverse genetics research method in many different eukaryotes but also holds great promise to contribute to the species-specific control of agricultural pests and to combat viral infections in beneficial and disease vectoring insects. However, in many economically important insect species, such as flies, mosquitoes, and caterpillars, systemic delivery of naked dsRNA does not trigger effective gene silencing. Although many components of the RNAi pathway have initially been deciphered in the fruit fly, Drosophila melanogaster, it will be of major importance to investigate this process in a wider variety of species, including dsRNA-sensitive insects such as locusts and beetles, to elucidate the factors responsible for the remarkable variability in RNAi efficiency, as observed in different insects. In this chapter, we review the current knowledge on the RNAi pathway, as well as the most recent insights into the mechanisms that might determine successful RNAi in insects.
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Affiliation(s)
- Niels Wynant
- Department of Animal Physiology and Neurobiology, KU Leuven, Naamsestraat, Leuven, Belgium.
| | - Dulce Santos
- Department of Animal Physiology and Neurobiology, KU Leuven, Naamsestraat, Leuven, Belgium
| | - Jozef Vanden Broeck
- Department of Animal Physiology and Neurobiology, KU Leuven, Naamsestraat, Leuven, Belgium
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Lee JH, Kim BK, Seo YI, Choi JH, Kang SW, Kang CK, Park WG, Kim HW. Four cDNAs encoding lipoprotein receptors from shrimp (Pandalopsis japonica): structural characterization and expression analysis during maturation. Comp Biochem Physiol B Biochem Mol Biol 2013; 169:51-62. [PMID: 24389120 DOI: 10.1016/j.cbpb.2013.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
As in all other oviparous animals, lipoprotein receptors play a critical role in lipid metabolism and reproduction in decapod crustaceans. Four full-length cDNAs encoding lipoprotein receptors (Paj-VgR, Paj-LpR1, Paj-LpR2A, and Paj-LpR2B) were identified from Pandalopsis japonica through a combination of EST screening and PCR-based cloning. Paj-LpR1 appears to be the first crustacean ortholog of insect lipophorin receptors, and its two paralogs, Paj-LpR2A and Paj-LpR2B, exhibited similar structural characteristics. Several transcriptional isoforms were also identified for all three Paj-LpRs. Each expression pattern was unique, suggesting different physiological roles for these proteins. Paj-VgR is an ortholog of vitellogenin (Vg) receptors from other decapod crustaceans. A phylogenetic analysis of lipoproteins and their receptors suggested that the nomenclature of Vgs from decapod crustaceans may need to be changed. A PCR-based transcriptional analysis showed that Paj-VgR and Paj-LpR2B are expressed almost exclusively in the ovary, whereas Paj-LpR1 and Paj-LpR2A are expressed in multiple tissues. The various transcriptional isoforms of the three Paj-LpRs exhibited unique tissue distribution profiles. A transcriptional analysis of each receptor using tissues with different GSI values showed that the change in transcription of Paj-VgRs, Paj-LpR2A and Paj-LpR1 was not as significant as that of Vgs during maturation. However, the transcriptional levels of Paj-LpR2B decreased in ovary at maturation, suggesting that their transcriptional regulation is involved in reproduction.
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Affiliation(s)
- Ji-Hyun Lee
- Interdisciplinary program of Biomedical Engineering, Pukyong National University, Busan, 608-737, South Korea
| | - Bo Kwang Kim
- Interdisciplinary program of Biomedical Engineering, Pukyong National University, Busan, 608-737, South Korea
| | - Young-Il Seo
- Fisheries Resources Research Division, National Fisheries Research and Development Institute, Busan, 619-902, South Korea
| | - Jung Hwa Choi
- Fisheries Resources Research Division, National Fisheries Research and Development Institute, Busan, 619-902, South Korea
| | - Seung-Wan Kang
- Gyeongsangnam-do Fisheries Resources Research Institute, South Korea
| | - Chang-Keun Kang
- POSTECH Ocean Science and Technology Institute, Pohang University of Science and Technology (POSTECH), Pohang 790-784, South Korea
| | - Won-gyu Park
- Department of Marine Biology, Pukyong National University, Busan 608-737, South Korea
| | - Hyun-Woo Kim
- Department of Marine Biology, Pukyong National University, Busan 608-737, South Korea; Interdisciplinary program of Biomedical Engineering, Pukyong National University, Busan, 608-737, South Korea.
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Swevers L, Vanden Broeck J, Smagghe G. The possible impact of persistent virus infection on the function of the RNAi machinery in insects: a hypothesis. Front Physiol 2013; 4:319. [PMID: 24204347 PMCID: PMC3817476 DOI: 10.3389/fphys.2013.00319] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 10/15/2013] [Indexed: 11/13/2022] Open
Abstract
RNAi experiments in insects are characterized by great variability in efficiency; for instance beetles and locusts are very amenable to dsRNA-mediated gene silencing, while other insect groups, most notably lepidopterans, are more refractory to RNAi. Several factors can be forwarded that could affect the efficiency of RNAi, such as the composition and function of the intracellular RNAi machinery, the mechanism of dsRNA uptake, the presence of dsRNA- and siRNA-degrading enzymes and non-specific activation of the innate immune response. In this essay, we investigate the evidence whether persistent infection with RNA viruses could be a major factor that affects the response to exogenous dsRNA in insects. The occurrence of RNA viruses in different insect groups will be discussed, as well as several mechanisms by which viruses could interfere with the process of RNAi. Finally, the impact of RNA virus infection on the design of dsRNA-based insect control strategies will be considered.
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Affiliation(s)
- Luc Swevers
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos," Athens, Greece
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25
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Entringer PF, Grillo LAM, Pontes EG, Machado EA, Gondim KC. Interaction of lipophorin with Rhodnius prolixus oocytes: biochemical properties and the importance of blood feeding. Mem Inst Oswaldo Cruz 2013; 108:836-44. [PMID: 24037104 PMCID: PMC3970653 DOI: 10.1590/0074-0276130129] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 11/11/2023] Open
Abstract
Lipophorin (Lp) is the main haemolymphatic lipoprotein in insects and transports lipids between different organs. In adult females, lipophorin delivers lipids to growing oocytes. In this study, the interaction of this lipoprotein with the ovaries of Rhodnius prolixus was characterised using an oocyte membrane preparation and purified radiolabelled Lp (125I-Lp). Lp-specific binding to the oocyte membrane reached equilibrium after 40-60 min and when 125I-Lp was incubated with increasing amounts of membrane protein, corresponding increases in Lp binding were observed. The specific binding of Lp to the membrane preparation was a saturable process, with a K(d) of 7.1 ± 0.9 x 10-8M and a maximal binding capacity of 430 ± 40 ng 125I-Lp/µg of membrane protein. The binding was calcium independent and pH sensitive, reaching its maximum at pH 5.2-5.7. Suramin inhibited the binding interaction between Lp and the oocyte membranes, which was completely abolished at 0.5 mM suramin. The oocyte membrane preparation from R. prolixus also showed binding to Lp from Manduca sexta. When Lp was fluorescently labelled and injected into vitellogenic females, the level of Lp-oocyte binding was much higher in females that were fed whole blood than in those fed blood plasma.
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Affiliation(s)
- Petter Franco Entringer
- Instituto de Bioquímica Médica
- Laboratório de Imunoparasitologia, Centro de Pesquisas Gonçalo Moniz-Fiocruz, Salvador, BA, Brasil
| | | | - Emerson Guedes Pontes
- Instituto de Bioquímica Médica
- Departamento de Química, Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular
| | - Ednildo Alcântara Machado
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular
| | - Katia Calp Gondim
- Instituto de Bioquímica Médica
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular
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Garbutt JS, Bellés X, Richards EH, Reynolds SE. Persistence of double-stranded RNA in insect hemolymph as a potential determiner of RNA interference success: evidence from Manduca sexta and Blattella germanica. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:171-8. [PMID: 22664137 DOI: 10.1016/j.jinsphys.2012.05.013] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/17/2012] [Accepted: 05/22/2012] [Indexed: 05/03/2023]
Abstract
RNA interference (RNAi) is a specific gene silencing mechanism mediated by double-stranded RNA (dsRNA), which has been harnessed as a useful reverse genetics tool in insects. Unfortunately, however, this technology has been limited by the variable sensitivity of insect species to RNAi. We propose that rapid degradation of dsRNA in insect hemolymph could impede gene silencing by RNAi and experimentally investigate the dynamics of dsRNA persistence in two insects, the tobacco hornworm, Manduca sexta, a species in which experimental difficulty has been experienced with RNAi protocols and the German cockroach, Blattella germanica, which is known to be highly susceptible to experimental RNAi. An ex vivo assay revealed that dsRNA was rapidly degraded by an enzyme in M. sexta hemolymph plasma, whilst dsRNA persisted much longer in B. germanica plasma. A quantitative reverse transcription PCR-based assay revealed that dsRNA, accordingly, disappeared rapidly from M. sexta hemolymph in vivo. The M. sexta dsRNAse is inactivated by exposure to high temperature and is inhibited by EDTA. These findings lead us to propose that the rate of persistence of dsRNA in insect hemolymph (mediated by the action of one or more nucleases) could be an important factor in determining the susceptibility of insect species to RNAi.
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Affiliation(s)
- Jennie S Garbutt
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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Roth Z, Khalaila I. Identification and characterization of the vitellogenin receptor in Macrobrachium rosenbergii and its expression during vitellogenesis. Mol Reprod Dev 2013; 79:478-87. [PMID: 22674884 DOI: 10.1002/mrd.22055] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In oviparous organisms, oocyte maturation depends on massive production of the egg yolk-precursor protein, vitellogenin (Vg). Vg is taken up by the developing oocytes through receptor-mediated endocytosis (RME), a process essential to successful reproduction. The aims of this study were to identify and characterize the yet-unknown vitellogenin receptor (VgR) from the pleocyamate crustacean Macrobrachium rosenbergii, and to investigate its expression levels during vitellogenesis and its interaction with Vg. The VgR gene was cloned, and its translated protein was specifically located at the oocyte membrane. Moreover, for the first time, a VgR protein was identified and sequenced by mass spectrometry. The putative MrVgR displayed high sequence similarity to VgRs from crustaceans, insects, and vertebrates, and its structure includes typical elements, such as an extracellular, lipoprotein-binding domain (LBD), EGF-like, and O-glycosylation domains, a transmembrane domain, and a short, C-terminal, cytosolic tail. In this article, we identify the first crustacean VgR protein, and present data demonstrating its high affinity for a Vg column followed by elution with suramin and EDTA. Additionally we demonstrate that VgR expression in the oocyte is elevated during vitellogenesis. Our results contribute to the fundamental understanding of oocyte maturation in crustaceans, and particularly elucidate Vg uptake through RME via the VgR.
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Affiliation(s)
- Ziv Roth
- Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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28
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Tanaka ED, Piulachs MD. Dicer-1 is a key enzyme in the regulation of oogenesis in panoistic ovaries. Biol Cell 2012; 104:452-61. [PMID: 22462497 DOI: 10.1111/boc.201100044] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 03/26/2012] [Indexed: 11/26/2022]
Abstract
BACKGROUND INFORMATION In insects, the action of microRNAs (miRNAs) on oogenesis has been explored only in dipterans, which possess meroistic ovaries, a highly modified ovarian type. Here we study miRNA function in the most primitive, panoistic type of ovaries using the phylogenetically basal insect Blattella germanica (Dictyoptera, Blattellidae) as model. RESULTS Dicer-1 (Dcr1), a key enzyme in miRNA biogenesis, was depleted using RNAi. Females treated with double-stranded RNA targeting Dicer-1, exhibited deep alterations in oocyte development; among them, the follicular epithelia of the basal oocytes did not develop, thus resulting in sterile females. CONCLUSIONS These effects derived from the absence of Dicer-1 suggest that miRNAs are crucial for the regulation of oogenesis in panoistic ovaries, the most primitive insect ovarian type.
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Affiliation(s)
- Erica Donato Tanaka
- Institut de Biologia Evolutiva (Universitat Pompeu Fabra-Consejo Superior de Investigaciones Cientificas), 08003 Barcelona, Spain
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29
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Soulages JL, Firdaus SJ, Hartson S, Chen X, Howard AD, Arrese EL. Developmental changes in the protein composition of Manduca sexta lipid droplets. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:305-320. [PMID: 22245367 PMCID: PMC3299933 DOI: 10.1016/j.ibmb.2012.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 12/22/2011] [Accepted: 01/02/2012] [Indexed: 05/31/2023]
Abstract
The lipid droplets (LDs) are intracellular organelles mainly dedicated to the storage and provision of fatty acids. To accomplish these functions the LDs interact with other organelles and cytosolic proteins. In order to explore possible correlations between the physiological states of cells and the protein composition of LDs we have determined and compared the proteomic profiles of lipid droplets isolated from the fat bodies of 5th-instar larvae and adult Manduca sexta insects and from ovaries. These LD-rich tissues represent three clearly distinct metabolic states in regard to lipid metabolism: 1) Larval fat body synthesizes fatty acids (FA) and accumulates large amounts as triglyceride (TG); 2) Fat body from adult insects provides FA to support reproduction and flight; 3) Ovaries do not synthesize FA, but accumulate considerable amounts of TG in LDs. Major qualitative and semi-quantitative variations in the protein compositions of the LDs isolated from these three tissues were observed by MS/MS and partially validated by immuno-blotting. The differences observed included changes in the abundance of lipid droplet specific proteins, cytosolic proteins, mitochondrial proteins and also proteins associated with the machinery of protein synthesis. These results suggest that changes in the interaction of LDs with other organelles and cytosolic proteins are tightly related to the physiological state of cells. Herein, we summarize and compare the protein compositions of three subtypes of LDs and also describe for the first time the proteomic profile of LDs from an insect ovary. The compositions and compositional differences found among the LDs are discussed to provide a platform for future studies on the role of LDs, and their associated proteins, in cellular metabolism.
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Affiliation(s)
- Jose L Soulages
- Department of Biochemistry & Molecular Biology, Oklahoma State University, Stillwater, OK 74074, USA
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Benoit JB, Yang G, Krause TB, Patrick KR, Aksoy S, Attardo GM. Lipophorin acts as a shuttle of lipids to the milk gland during tsetse fly pregnancy. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:1553-61. [PMID: 21875592 PMCID: PMC3209505 DOI: 10.1016/j.jinsphys.2011.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 08/05/2011] [Accepted: 08/08/2011] [Indexed: 05/09/2023]
Abstract
During pregnancy in the viviparous tsetse fly, lipid mobilization is essential for the production of milk to feed the developing intrauterine larva. Lipophorin (Lp) functions as the major lipid transport protein in insects and closely-related arthropods. In this study, we assessed the role of Lp and the lipophorin receptor (LpR) in the lipid mobilization process during tsetse reproduction. We identified single gene sequences for GmmLp and GmmLpR from the genome of Glossinamorsitansmorsitans, and measured spatial and temporal expression of gmmlp and gmmlpr during the female reproductive cycle. Our results show that expression of gmmlp is specific to the adult fat body and larvae. In the adult female, gmmlp expression is constitutive. However transcript levels increase in the larva as it matures within the mother's uterus, reaching peak expression just prior to parturition. GmmLp was detected in the hemolymph of pregnant females and larvae, but not in the uterine fluid or larval gut contents ruling out the possibility of direct transfer of GmmLp from mother to offspring. Transcripts for gmmlpr were detected in the head, ovaries, midgut, milk gland/fat body, ovaries and developing larva. Levels of gmmlpr remain stable throughout the first and second gonotrophic cycles with a slight dip observed during the first gonotrophic cycle. GmmLpR was detected in multiple tissues, including the midgut, fat body, milk gland, spermatheca and head. Knockdown of gmmlp by RNA interference resulted in reduced hemolymph lipid levels, delayed oocyte development and extended larval gestation. Similar suppresion of gmmlpr did not significantly reduce hemolymph lipid levels or oogenesis duration, but did extend the duration of larval development. Thus, GmmLp function as the primary shuttle for lipids originating from the midgut and fat body to the ovaries and milk gland to supply resources for developing oocytes and larval nourishment, respectively. Once in the milk gland however, lipids are apparently transferred into the developing larva not by lipophorin but by another carrier lipoprotein.
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Affiliation(s)
- Joshua B. Benoit
- Division of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT 06511
| | - Guangxiao Yang
- Division of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT 06511
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520
| | - Tyler B. Krause
- Division of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT 06511
| | - Kevin R. Patrick
- Division of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT 06511
| | - Serap Aksoy
- Corresponding author Serap Aksoy, 60 College Street, Division of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT 06511,
| | - Geoffrey M. Attardo
- Division of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT 06511
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Fruttero LL, Frede S, Rubiolo ER, Canavoso LE. The storage of nutritional resources during vitellogenesis of Panstrongylus megistus (Hemiptera: Reduviidae): the pathways of lipophorin in lipid delivery to developing oocytes. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:475-486. [PMID: 21277855 DOI: 10.1016/j.jinsphys.2011.01.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 01/18/2011] [Accepted: 01/19/2011] [Indexed: 05/30/2023]
Abstract
In this work, we have analyzed the pathways by which lipophorin (Lp) delivers its lipid cargo to developing oocytes of Panstrongylus megistus, a hematophagous vector of Chagas' disease. Lp, vitellin, total lipids and proteins were measured in ovarian tissues at different stages of the reproductive cycle. Localization of Lp in developing oocytes, mainly at their cortical area, was demonstrated by immunofluorescence assays using an anti-Lp antibody labeled with FITC. In vivo approaches injecting fluorescently labeled Lp to follow the course of the entire particle (Lp-DiI or Lp-Oregon Green) or its lipid cargo (Lp-Bodipy-FA) were monitored by laser scanning confocal microscopy. Significant increases in the amounts of lipids, proteins and vitellin were observed in ovarian tissue with the progress of vitellogenesis. Unexpectedly, an increase in the amount of Lp was also observed. The experiments in vivo demonstrated that the uptake of fluorescent Lp labeled on its protein or lipid moiety by developing oocytes occurred very fast, being impaired at low temperatures. The co-injection of fluorescent Lp and vitellogenin (Vg) showed that both particles co-localized inside yolk bodies, confirming the endocytic pathway for Lp. When the fate of lipids transferred to oocytes was evaluated in vitellogenic females by co-injecting Lp-Bodipy-FA and Lp-DiI, the signal for Bodipy-FA was found in both lipid droplets and yolk bodies. In contrast, in injected females kept at 4°C the fluorescence was reduced, being observed exclusively in lipid droplets, implying that lipid transfer to the oocyte was diminished but not abolished. Taken together, the results demonstrate that in the hematophagous P. megistus, the storage of lipid resources by developing oocytes occurs by the convergence of different pathways by which Lp maximizes the delivery of its lipid cargo. In addition, it was also shown that, to some extent, lipids stored in the oocyte lipid droplets can also originate from endocytosed Vg. The relevance of these events in the context of the physiology of reproduction in P. megistus is discussed.
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Affiliation(s)
- Leonardo L Fruttero
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología, Facultad de Ciencias Químicas-Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina
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32
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Parra-Peralbo E, Culi J. Drosophila lipophorin receptors mediate the uptake of neutral lipids in oocytes and imaginal disc cells by an endocytosis-independent mechanism. PLoS Genet 2011; 7:e1001297. [PMID: 21347279 PMCID: PMC3037410 DOI: 10.1371/journal.pgen.1001297] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 01/07/2011] [Indexed: 11/18/2022] Open
Abstract
Lipids are constantly shuttled through the body to redistribute energy and metabolites between sites of absorption, storage, and catabolism in a complex homeostatic equilibrium. In Drosophila, lipids are transported through the hemolymph in the form of lipoprotein particles, known as lipophorins. The mechanisms by which cells interact with circulating lipophorins and acquire their lipidic cargo are poorly understood. We have found that lipophorin receptor 1 and 2 (lpr1 and lpr2), two partially redundant genes belonging to the Low Density Lipoprotein Receptor (LDLR) family, are essential for the efficient uptake and accumulation of neutral lipids by oocytes and cells of the imaginal discs. Females lacking the lpr2 gene lay eggs with low lipid content and have reduced fertility, revealing a central role for lpr2 in mediating Drosophila vitellogenesis. lpr1 and lpr2 are transcribed into multiple isoforms. Interestingly, only a subset of these isoforms containing a particular LDLR type A module mediate neutral lipid uptake. Expression of these isoforms induces the extracellular stabilization of lipophorins. Furthermore, our data indicate that endocytosis of the lipophorin receptors is not required to mediate the uptake of neutral lipids. These findings suggest a model where lipophorin receptors promote the extracellular lipolysis of lipophorins. This model is reminiscent of the lipolytic processing of triglyceride-rich lipoproteins that occurs at the mammalian capillary endothelium, suggesting an ancient role for LDLR–like proteins in this process. Understanding the complex mechanisms that regulate the storage of caloric surpluses in the form of fat is critical in view of the public health problems caused by the continuous rise of obesity and diabetes. Important advances in the field have been obtained from studies using simple animal models like worms or flies. Here we focus on the molecular mechanisms involved in how cells capture neutral lipids from the extracellular milieu, using the fruit fly Drosophila melanogaster as a model organism. Lipids are transported through the blood or the insect hemolymph as small particles known as lipoproteins. We show that two Drosophila proteins related to the mammalian Low Density Lipoprotein Receptor, Lipophorin Receptor 1 and 2, are essential for the cellular acquisition of neutral lipids from extracellular lipoproteins. We have found that the endocytic uptake of the lipoprotein particles was not required for this process. Instead, we propose that lipophorin receptors favor the extracellular hydrolysis of lipids contained in lipoproteins, followed by uptake of the released free fatty acids. This process is similar to the extracellular processing of lipoproteins that takes place in the capillaries of mammals, suggesting an ancient role for LDLR–related proteins in the extracellular processing of lipoproteins.
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Affiliation(s)
- Esmeralda Parra-Peralbo
- Centro Andaluz de Biología del Desarrollo (CSIC-UPO), Universidad Pablo de Olavide, Sevilla, Spain
| | - Joaquim Culi
- Centro Andaluz de Biología del Desarrollo (CSIC-UPO), Universidad Pablo de Olavide, Sevilla, Spain
- * E-mail:
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33
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Colonello-Frattini NA, Guidugli-Lazzarini KR, Simões ZLP, Hartfelder K. Mars is close to venus--female reproductive proteins are expressed in the fat body and reproductive tract of honey bee (Apis mellifera L.) drones. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1638-1644. [PMID: 20600084 DOI: 10.1016/j.jinsphys.2010.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 06/16/2010] [Accepted: 06/16/2010] [Indexed: 05/29/2023]
Abstract
Vitellogenin (Vg) and lipophorin (Lp) are lipoproteins which play important roles in female reproductive physiology of insects. Both are actively taken up by growing oocytes and especially Vg and its receptor are considered as female-specifically expressed. The finding that the fat body of in honey bee (Apis mellifera) drones synthesizes Vg and is present in hemolymph has long been viewed as a curiosity. The recent paradigm change concerning the role played by Vg in honey bee life history, especially social division of labor, has now led us to investigate whether a physiological constellation similar to that seen in female reproduction may also be represented in the male sex. By means of Western blot analysis we could show that both Vg and Lp are present in the reproductive tract of adult drones, including the accessory (mucus) glands, but apparently are not secreted. Furthermore, we analyzed the transcript levels of the genes encoding these proteins (vg and lp), as well as their putative receptors (Amvgr and Amlpr) in fat body and accessory glands. Whereas lp, vg and Amlpr transcript levels decreased with age in both tissues, Amvgr mRNA levels increased with age in fat body. To our knowledge this is the first report that vitellogenin and its receptor are co-expressed in the reproductive system of a male insect. We interpret these findings as a cross-sexual transfer of a social physiological trait, associated with the rewiring of the juvenile hormone/vitellogenin circuitry that occurred in the female sex of honey bees.
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Affiliation(s)
- Nínive Aguiar Colonello-Frattini
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
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Abstract
The increasing availability of insect genomes has revealed a large number of genes with unknown functions and the resulting problem of how to discover these functions. The RNA interference (RNAi) technique, which generates loss-of-function phenotypes by depletion of a chosen transcript, can help to overcome this challenge. RNAi can unveil the functions of new genes, lead to the discovery of new functions for old genes, and find the genes for old functions. Moreover, the possibility of studying the functions of homologous genes in different species can allow comparisons of the genetic networks regulating a given function in different insect groups, thereby facilitating an evolutionary insight into developmental processes. RNAi also has drawbacks and obscure points, however, such as those related to differences in species sensitivity. Disentangling these differences is one of the main challenges in the RNAi field.
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Affiliation(s)
- Xavier Bellés
- Institut de Biologia Evolutiva (CSIC-UPF), Barcelona, Spain.
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Abstract
The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects.
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Abstract
How does a juvenile insect transform into an adult? This question, which sums up the wonder of insect metamorphosis, has fascinated mankind since ancient times. Modern physiology has established the endocrine basis regulating these transformations, which mainly depend on two hormone types: ecdysteroids, which promote molts, and juvenile hormones, which repress the transformation into the adult stage. The interplay of these two hormones regulates the genes involved in juvenile and adult programs and the shift from one to the other. microRNAs (miRNAs) are small noncoding RNAs, which participate in many biological processes, and we wondered whether they might be also involved in insect metamorphosis. In insects, Dicer-1 ribonuclease transforms miRNA precursors into mature miRNAs. Thus, using systemic RNA interference (RNAi) to silence the expression of Dicer-1 in the hemimetabolan insect Blattella germanica, we depleted miRNA contents in the last instar nymph. This practically inhibited metamorphosis after the next molt, as the resulting specimens showed nymphoid features and were able to molt again. The experiments show that miRNAs play a key role in hemimetabolan metamorphosis, perhaps regulating genes that are juvenile hormone targets.
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Tufail M, Elmogy M, Ali Fouda MM, Elgendy AM, Bembenek J, Trang LTD, Shao QM, Takeda M. Molecular cloning, characterization, expression pattern and cellular distribution of an ovarian lipophorin receptor in the cockroach, Leucophaea maderae. INSECT MOLECULAR BIOLOGY 2009; 18:281-294. [PMID: 19523061 DOI: 10.1111/j.1365-2583.2009.00865.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A cDNA that encodes a lipophorin receptor (LpR) with a predicted structure similar to that of the low density lipoprotein receptor (LDLR) gene superfamily was cloned from ovaries of the cockroach, Leucophaea maderae (Lem) and characterized. This is the first LpR sequenced from the order Dictyoptera. The cDNA has a length of 3362 bp coding for an 888-residue mature protein with a predicted molecular mass of ~99.14 kDa and a pI value of 4.68. The deduced amino acid sequence showed that the LemLpR harbours eight ligand-binding repeats (LBRs) at the N-terminus similar to the other insect LpRs, and thus resembles vertebrate VLDLRs. In addition to eight tandemly arranged LBRs, the five-domain receptor contains an O-linked sugar region and the classic LDLR internalization signal, FDNPVY. Northern blot analysis revealed the presence of ~4.0 kb ovarian mRNA that was transcribed throughout oogenesis with its peak especially during late previtellogenic and vitellogenic periods (from days 3 to 11). LpR transcript(s) or homologues of LDLRs were also detected in the head, midgut, Malpighian tubules, muscles and in the fat body. RNA in situ hybridization and immunocytochemistry localized the LpR mRNA and protein to germ line-derived cells, the oocytes, and revealed that LpR gene transcription and translation starts very early during oocyte differentiation in the germarium. LpR protein was evenly distributed throughout the cytoplasm during previtellogenic periods of oogenesis. However, during vitellogenic stages, the receptor was accumulated mainly in the cortex of the oocyte. Immunoblot analysis probed an ovarian LpR protein of ~115 and 97 kDa under reducing and nonreducing conditions, respectively. The protein signal appeared on day 2, increased every day and was high during vitellogenic periods from day 4 to day 7. Southern blot analysis suggested the presence of a single copy of the LpR gene in the genome of Le. maderae.
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Fruttero LL, Rubiolo ER, Canavoso LE. Biochemical and cellular characterization of lipophorin-midgut interaction in the hematophagous Panstrongylus megistus (Hemiptera: Reduviidae). INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2009; 39:322-331. [PMID: 19507302 DOI: 10.1016/j.ibmb.2009.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In order to better understand the metabolism of dietary lipids in hematophagous insects, we have performed a biochemical and cellular characterization of lipophorin (Lp)-midgut interaction in Panstrongylus megistus, a vector of Chagas' disease. The study was accomplished by solid-phase binding assays or with iodinated Lp ((125)I-Lp), using midgut membranes from fifth instar nymphs after ecdysis and after insects received a blood meal. Results obtained from both physiological conditions indicated that Lp interacted specifically with the midgut, implying the participation of receptors. Binding capacity of lipophorin to membranes was dependent on the amount of membranes added in the system, reaching saturation at 0.1 microg/ml. However, membranes obtained after a blood meal exhibited higher binding activity. Saturation kinetics results using (125)I-Lp suggested a single binding site with high affinity for Lp in the midgut membranes (K(d) = 5.1 +/- 3.6 x 10(-8) M). The unrelated lipoprotein, human LDL, did not compete with Lp for its binding site in the midgut. The binding was dependent on pH and the treatment of membranes with trypsin or heat causes a significant inhibition of the binding. Midgut-Lp interaction was affected by changes in ionic strength and by suramin, but showed no requirement of calcium. Ligand blotting assays revealed two membrane proteins that specifically bound Lp (61 and 45 kDa). At cellular level, Lp binding sites were located mainly at the basal plasma membrane of isolated enterocytes. Labeled Lp with fluorescent probes directed to its proteins or its phospholipids fraction co-localized mainly at the basement membrane of the midgut. In addition, no intracellular Lp was observed at any condition. The lack of an endocytic pathway for Lp in the midgut of P. megistus is analyzed in the context of insect physiology.
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Affiliation(s)
- Leonardo L Fruttero
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología, Universidad Nacional de Córdoba, Argentina
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Irles P, Bellés X, Piulachs MD. Identifying genes related to choriogenesis in insect panoistic ovaries by Suppression Subtractive Hybridization. BMC Genomics 2009; 10:206. [PMID: 19405973 PMCID: PMC2683872 DOI: 10.1186/1471-2164-10-206] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Accepted: 04/30/2009] [Indexed: 12/13/2022] Open
Abstract
Background Insect ovarioles are classified into two categories: panoistic and meroistic, the later having apparently evolved from an ancestral panoistic type. Molecular data on oogenesis is practically restricted to meroistic ovaries. If we aim at studying the evolutionary transition from panoistic to meroistic, data on panoistic ovaries should be gathered. To this end, we planned the construction of a Suppression Subtractive Hybridization (SSH) library to identify genes involved in panoistic choriogenesis, using the cockroach Blattella germanica as model. Results We constructed a post-vitellogenic ovary library by SSH to isolate genes involved in choriogenesis in B. germanica. The tester library was prepared with an ovary pool from 6- to 7-day-old females, whereas the driver library was prepared with an ovary pool from 3- to 4-day-old females. From the SSH library, we obtained 258 high quality sequences which clustered into 34 unique sequences grouped in 19 contigs and 15 singlets. The sequences were compared against non-redundant NCBI databases using BLAST. We found that 44% of the unique sequences had homologous sequences in known genes of other organisms, whereas 56% had no significant similarity to any of the databases entries. A Gene Ontology analysis was carried out, classifying the 34 sequences into different functional categories. Seven of these gene sequences, representative of different categories and processes, were chosen to perform expression studies during the first gonadotrophic cycle by real-time PCR. Results showed that they were mainly expressed during post-vitellogenesis, which validates the SSH technique. In two of them corresponding to novel genes, we demonstrated that they are specifically expressed in the cytoplasm of follicular cells in basal oocytes at the time of choriogenesis. Conclusion The SSH approach has proven to be useful in identifying ovarian genes expressed after vitellogenesis in B. germanica. For most of the genes, functions related to choriogenesis are postulated. The relatively high percentage of novel genes obtained and the practical absence of chorion genes typical of meroistic ovaries suggest that mechanisms regulating chorion formation in panoistic ovaries are significantly different from those of meroistic ones.
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Affiliation(s)
- Paula Irles
- Institut de Biologia Evolutiva (UPF-CSIC), Passeig Marítim de la Barceloneta, Barcelona, Spain.
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40
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Roosendaal SD, Van Doorn JM, Valentijn KM, Van der Horst DJ, Rodenburg KW. Delipidation of insect lipoprotein, lipophorin, affects its binding to the lipophorin receptor, LpR: implications for the role of LpR-mediated endocytosis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2009; 39:135-144. [PMID: 19049873 DOI: 10.1016/j.ibmb.2008.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 10/22/2008] [Accepted: 10/24/2008] [Indexed: 05/27/2023]
Abstract
The insect lipophorin receptor (LpR), an LDL receptor (LDLR) homologue that is expressed during restricted periods of insect development, binds and endocytoses high-density lipophorin (HDLp). However, in contrast to LDL, HDLp is not lysosomally degraded, but recycled in a transferrin-like manner, leaving a function of receptor-mediated uptake of HDLp to be uncovered. Since a hallmark of circulatory HDLp is its ability to function as a reusable shuttle that selectively loads and unloads lipids at target tissues without being endocytosed or degraded, circulatory HDLp can exist in several forms with respect to lipid loading. To investigate whether lipid content of the lipoprotein affects binding and subsequent endocytosis by LpR, HDLp was partially delipidated in vitro by incubation with alpha-cyclodextrin, yielding a particle of buoyant density 1.17g/mL (HDLp-1.17). Binding experiments demonstrated that LpR bound HDLp-1.17 with a substantially higher affinity than HDLp both in LpR-transfected Chinese hamster ovary (CHO) cells and isolated insect fat body tissue endogenously expressing LpR. Similar to HDLp, HDLp-1.17 was targeted to the endocytic recycling compartment after endocytosis in CHO(LpR) cells. The complex of HDLp-1.17 and LpR appeared to be resistant to endosomal pH, as was recently demonstrated for the LpR-HDLp complex, corroborating that HDLp-1.17 is recycled similar to HDLp. This conclusion was further supported by the observation of a significant decrease with time of HDLp-1.17-containing vesicles after endocytosis of HDLp-1.17 in LpR-expressing insect fat body tissue. Collectively, our results indicate that LpR favors the binding and subsequent endocytosis of HDLp-1.17 over HDLp, suggesting a physiological role for LpR in selective endocytosis of relatively lipid-unloaded HDLp particles, while lipid reloading during their intracellular itinerary might result in decreased affinity for LpR and thus allows recycling.
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Affiliation(s)
- Sigrid D Roosendaal
- Division of Endocrinology and Metabolism, Department of Biology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Tufail M, Takeda M. Insect vitellogenin/lipophorin receptors: molecular structures, role in oogenesis, and regulatory mechanisms. JOURNAL OF INSECT PHYSIOLOGY 2009; 55:87-103. [PMID: 19071131 DOI: 10.1016/j.jinsphys.2008.11.007] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 11/10/2008] [Accepted: 11/13/2008] [Indexed: 05/27/2023]
Abstract
Insect vitellogenin and lipophorin receptors (VgRs/LpRs) belong to the low-density lipoprotein receptor (LDLR) gene superfamily and play a critical role in oocyte development by mediating endocytosis of the major yolk protein precursors Vg and Lp, respectively. Precursor Vg and Lp are synthesized, in the majority of insects, extraovarially in the fat body and are internalized by competent oocytes through membrane-bound receptors (i.e., VgRs and LpRs, respectively). Structural analysis reveals that insect VgRs/LpRs and all other LDLR family receptors share a group of five structural domains: clusters of cysteine-rich repeats constituting the ligand-binding domain (LBD), epidermal growth factor (EGF)-precursor homology domain that mediates the acid-dependent dissociation of ligands, an O-linked sugar domain of unknown function, a transmembrane domain anchoring the receptor in the plasma membrane, and a cytoplasmic domain that mediates the clustering of the receptor into the coated pits. The sequence analysis indicates that insect VgRs harbor two LBDs with five repeats in the first and eight repeats in the second domain as compared to LpRs which have a single 8-repeat LBD. Moreover, the cytoplasmic domain of all insect VgRs contains a LI internalization signal instead of the NPXY motif found in LpRs and in the majority of other LDLR family receptors. The exception is that of Solenopsis invicta VgR, which also contains an NPXY motif in addition to LI signal. Cockroach VgRs still harbor another motif, NPTF, which is also believed to be a functional internalization signal. The expression studies clearly demonstrate that insect VgRs are ovary-bound receptors of the LDLR family as compared to LpRs, which are transcribed in a wide range of tissues including ovary, fat body, midgut, brain, testis, Malpighian tubules, and muscles. VgR/LpR mRNA and the protein were detected in the germarium, suggesting that the genes involved in receptor-endocytotic machinery are specifically expressed long before they are functionally required.
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Affiliation(s)
- Muhammad Tufail
- Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan.
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Van der Horst DJ, Roosendaal SD, Rodenburg KW. Circulatory lipid transport: lipoprotein assembly and function from an evolutionary perspective. Mol Cell Biochem 2009; 326:105-19. [PMID: 19130182 DOI: 10.1007/s11010-008-0011-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 06/05/2008] [Indexed: 02/07/2023]
Abstract
Circulatory transport of neutral lipids (fat) in animals relies on members of the large lipid transfer protein (LLTP) superfamily, including mammalian apolipoprotein B (apoB) and insect apolipophorin II/I (apoLp-II/I). Latter proteins, which constitute the structural basis for the assembly of various lipoproteins, acquire lipids through microsomal triglyceride transfer protein (MTP)--another LLTP family member--and bind them by means of amphipathic structures. Comparative research reveals that LLTPs have evolved from the earliest animals and additionally highlights the structural and functional adaptations in these lipid carriers. For instance, in contrast to mammalian apoB, the insect apoB homologue, apoLp-II/I, is post-translationally cleaved by a furin, resulting in their appearance of two non-exchangeable apolipoproteins in the insect low-density lipoprotein (LDL) homologue, high-density lipophorin (HDLp). An important difference between mammalian and insect lipoproteins relates to the mechanism of lipid delivery. Whereas in mammals, endocytic uptake of lipoprotein particles, mediated via members of the LDL receptor (LDLR) family, results in their degradation in lysosomes, the insect HDLp was shown to act as a reusable lipid shuttle which is capable of reloading lipid. Although the recent identification of a lipophorin receptor (LpR), a homologue of LDLR, reveals that endocytic uptake of HDLp may constitute an additional mechanism of lipid delivery, the endocytosed lipoprotein appears to be recycled in a transferrin-like manner. Binding studies indicate that the HDLp-LpR complex, in contrast to the LDL-LDLR complex, is resistant to dissociation at endosomal pH as well as by treatment with EDTA mimicking the drop in Ca(2+) concentration in the endosome. This remarkable stability of the ligand-receptor complex may provide a crucial key to the recycling mechanism. Based on the binding and dissociation capacities of mutant and hybrid receptors, the specific binding interaction of the ligand-binding domain of the receptor with HDLp was characterized. These structural similarities and functional adaptations of the lipid transport systems operative in mammals and insects are discussed from an evolutionary perspective.
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Affiliation(s)
- Dick J Van der Horst
- Division of Endocrinology and Metabolism, Department of Biology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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Guidugli-Lazzarini KR, do Nascimento AM, Tanaka ED, Piulachs MD, Hartfelder K, Bitondi MG, Simões ZLP. Expression analysis of putative vitellogenin and lipophorin receptors in honey bee (Apis mellifera L.) queens and workers. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:1138-1147. [PMID: 18606165 DOI: 10.1016/j.jinsphys.2008.04.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 04/18/2008] [Accepted: 04/21/2008] [Indexed: 05/26/2023]
Abstract
Two members of the low density lipoprotein receptor (LDLR) family were identified as putative orthologs for a vitellogenin receptor (Amvgr) and a lipophorin receptor (Amlpr) in the Apis mellifera genome. Both receptor sequences have the structural motifs characteristic of LDLR family members and show a high degree of similarity with sequences of other insects. RT-PCR analysis of Amvgr and Amlpr expression detected the presence of both transcripts in different tissues of adult female (ovary, fat body, midgut, head and specifically hypopharyngeal gland), as well as in embryos. In the head RNA samples we found two variant forms of AmLpR: a full length one and a shorter one lacking 29 amino acids in the O-linked sugar domain. In ovaries the expression levels of the two honey bee LDLR members showed opposing trends: whereas Amvgr expression was upregulated as the ovaries became activated, Amlpr transcript levels gradually declined. In situ hybridization analysis performed on ovaries detected Amvgr mRNA exclusively in germ line cells and corroborated the qPCR results showing an increase in Amvgr gene expression concomitant with follicle growth.
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Affiliation(s)
- Karina Rosa Guidugli-Lazzarini
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, SP, Brazil.
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Mekuchi M, Ohira T, Kawazoe I, Jasmani S, Suitoh K, Kim YK, Jayasankar V, Nagasawa H, Wilder MN. Characterization and Expression of the Putative Ovarian Lipoprotein Receptor in the Kuruma Prawn, Marsupenaeus japonicus. Zoolog Sci 2008; 25:428-37. [DOI: 10.2108/zsj.25.428] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 01/22/2008] [Indexed: 11/17/2022]
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45
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Roosendaal SD, Kerver J, Schipper M, Rodenburg KW, Van der Horst DJ. The complex of the insect LDL receptor homolog, lipophorin receptor, LpR, and its lipoprotein ligand does not dissociate under endosomal conditions. FEBS J 2008; 275:1751-66. [DOI: 10.1111/j.1742-4658.2008.06334.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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